Geology and Paleontology of the Lee Creek Mine, North Carolina, II CLAYTON E. RAY EDITOR SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY • NUMBER 51 SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTION Emphasis upon publication as a means of "diffusing knowledge" was expressed by the first Secretary of the Smithsonian. In his formal plan for the institution, Joseph Henry outlined a program that included the following statement: "It is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes made from year to year in all branches of knowledge." This theme of basic research has been adhered to through the years by thousands of titles Issued in series publications under the Smithsonian impnnt, commencing with Smittisonian Contributions to Knowledge in 1848 and continuing with the following active series: Smittisonian Contributions to Anttiropology Smithsonian Contributions to Astropfiysics Smitt)sonian Contributions to Botany Smittisonian Contributions to the Earth Sciences Smithsonian Contributions to the Marine Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Folklife Studies Smithsonian Studies in Air and Space Smithsonian Studies in History and Technology In these series, the Institution publishes small papers and full-scale monographs that report the research and collections of its various museums and bureaux or of professional colleagues in the world of science and scholarship. The publications are distributed by mailing lists to libranes, universities, and similar institutions throughout the world. Papers or monographs submitted for series publication are received by the Smithsonian Institution Press, subject to its own review for format and style, only through departments of the vanous Smithsonian museums or bureaux, where the manuscnpts are given substantive review. Press requirements for manuscnpt and art preparation are outlined on the inside back cover. Robert McC. Adams Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY • NUMBER 61 Geology and Paleontology ofthe Lee Creek Mine, North Carolina, II Clayton E. Ray EDITOR SMITHSONIAN INSTITUTION PRESS Washington, D.C. 1987 JUN 15 1987 ABSTRACT Ray, Clayton E., editor. Geology and Paleontology ofthe Lee Creek Mine, North Carolina, II. Smithsonian Contributions to Paleobiology, number 61, 283 pages, 80 plates, 49 figures, 21 tables, 1987.—Volume I of this projected series of three volumes included the prologue to the series, a biography of Remington Kellogg, and 13 papers on geology and paleontology other than Mollusca and Vertebrata (except otoliths). It was published in 1983 as Smithsonian Contributions to Paleobiology number 53. The present volume consists of a foreword and five chapters devoted to molluscan paleontology. The foreword recounts the earliest scientific publication of New World fossils, all mollusks, and reproduces Martin Lister's illustrations of them. William M. Furnish and Brian F. Glenister record the nautilid genus Aturia from the Pungo River Formation and discuss its occurrence elsewhere. Druid Wilson describes a new pycnodont oyster from the Pungo River Formation and lists the Cenozoic pycnodonts from the Atlantic and Gulf Coastal Plain; he also summarizes the stratigraphic and geographic occurrences of the subgenera of Ecphora, Ecphora and Stenomphalus, naming a new species of each from the Pungo River Formation, and a new species of the former from the St. Marys Formation of Maryland. Thomas G. Gibson clarifies the relationships and stratigraphic utility of 17 taxa (including one new species from the Pungo River Formation) of pectinid bivalves on the basis of biometric study of large samples from lower Miocene to lower Pleistocene beds in and near the mine. Lauck W. Ward and Blake W. Blackwelder describe a molluscan fauna of 194 species, including 30 new species and 3 new subspecies, from the Chowan River (upper Pliocene) and James City (lower Pleistocene) formations, and conclude that the fauna reflects a subtropical thermal regime and that it was deposited under open marine conditions at depths not exceeding 25 meters. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Tiie trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Geology and paleontology of the Lee Creek Mine, North Carolina. (Smithsonian contributions to paleobiology ; no. 53) Includes bibliographies. Supt of Docs, no.: SI 1.30 : 61 1. Geology, Stratigraphic—Tertiary. 2. Geology, Stratigraphic—Pleistocene. 3. Geology—North Car- olina—Lee Creek Mine Region. 4. Paleontology—North Carolina—Lee Creek Mine Region. I. Ray, Clayton Edward. II. Series: Smithsonian contributions to paleobiology ; no. 53, etc. QE701.S56 no. 53, etc. [QE691] 560 s. 82-600265 [551.7'8'09756] Contents Page FOREWORD, by Clayton E. Ray 1 MIOCENE CEPHALOPODS FROM NORTH CAROLINA, by William M. Furnish and Brian F. Glenister 9 A NEW PYCNODONT OYSTER FROM THE PUNGO RIVER FORMATION, AND AN ANNOTATED LIST OF THE CENOZOIC PYCNODONTS OF THE ATLANTIC AND GULF COASTAL PLAIN, by Druid Wilson 13 SPECIES OF ECPHORA, INCLUDING THE SUBGENUS STENOMPHALUS, IN THE PUNGO RIVER FORMATION, by Druid Wilson 21 MIOCENE AND PLIOCENE PECTINIDAE (BIVALVIA) FROM THE LEE CREEK MINE AND ADJACENT AREAS, by Thomas G. Gibson 31 LATE PLIOCENE AND EARLY PLEISTOCENE MOLLUSCA FROM THE JAMES CITY AND CHOWAN RIVER FORMATIONS AT THE LEE CREEK MINE, by Lauck W. Ward and Blake W. Blackwelder 113 Dedicated to Remington Kellogg 1892-1969 Geology and Paleontology ofthe Lee Creek Mine, North Carolina, II Foreword Clayton E. Ray Foreword . . . front matter likely to be of interest but not necessarily essential for the understanding of the text of a book and commonly written by someone other than the author[s] of the text. WEBSTER'S THIRD NEW INTERNATIONAL DICTIONARY, 1964. The first of three proposed volumes on the "Geology and Paleontology of the Lee Creek Mine, North Carolina," has now been published (Ray, 1983). This, the second, volume is devoted exclusively to the Mollusca. Truly comprehensive coverage of this most conspicuous component of the Lee Creek macrofauna justifiably could have occupied at least twice the space. Faunal studies ofthe mollusks ofthe Pungo River and Yorktown formations comparable in scope to those of the James City and Chowan River formations (Ward and Blackwelder, this volume) remain as prime de- siderata. A mollusk-rich, late Pleistocene bed of regional significance became well exposed by mining too late for inclusion in this volume. Detailed studies as dictated by abundance and state of knowledge of given taxonomic groups, exemplified by the chapters on Aturia (Furnish and Glenister, this volume), pycnodonts and ecphoras (Wilson, this volume), and pectens (Gibson, this volume), would be equally well warranted for numerous additional taxa. The rich shell beds of the middle Atlantic Coastal Plain were of practical interest from the early days of British settlement, as a source of lime for mortar (Ray, 1983:4). Later, in the nineteenth century, these "shell marls" were used extensively to improve the argicultural lands of the coastal plain (see, for example, Olmsted, 1827; Groom, Clayton E. Ray, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. 1835; Emmons, 1858; Mitchell, 1981; Allmendinger, 1985). Mollusks from the Yorktown Formation of Virginia were the first fossils of any kind from the Western Hemisphere to receive scientific attention and to be illustrated in publi- cation, both nearly 300 years ago. The centerpiece of this story is the classical monument of malacology, Martin List- er's Historiae Conchyliorum, parts of which were published for the first time at least from 1685 to 1692, if not to 1697, and probably posthumously, as late as 1770. Some aspects ofthe paleontological part ofthe story have been presented by sub.sequent authors, but as yet not both completely and correctly. The problems stem primarily from Lister's con- fusing practices in the printing, distributing, and publishing of his great work, a subject of research in itself beyond our scope here, to which a good introduction may be gained from Wilkins(1957), Sawyer (1962), and Keynes (1981). It is unlikely that any two copies of the work as prepared during Lister's lifetime are identical; plates were repeatedly modified as successive "proofs" were printed and variously distributed; some plate numbers were omitted and others duplicated; in no case is it correct to cite 1685 as date of publication in connection with North American fossils. That Lister's 1000-plus plates include representation of some North American fossil shells was recognized nearly 200 years ago by Lightfoot (1786:162), who listed as num- ber 3516 in his catalogue for auction of the Portland SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Museum "a very curious and rare species of Buccinum in a fossil state, having four high sharp ridges, from Maryland, very rare—Lister, 1059.2." However, his observation seems to have had no impact on contemporary or later authors. Other early authors apparently did not recognize as a fossil the specimen represented by Lister (e.g., Schroter, 1783:361; Dillwyn, 1823:48), and Dillwyn referred it to the living species Buccinum scala, regarded as a junior synonym of the Indo-Pacific Thais (Trochia) cingulata by Dodge (1956:235-237), and earlier by Tryon (1880:170), who also noted that "the normal development of ribs strikingly re- sembles the fossil Rapana (Ecphora) quadricostata. Say, of the United States." For practical purposes recognition of the significance of Lister s plates for North American paleontology came when Say (1824:134) ascribed a shell illustrated by Lister to his own new species, Pecten jeffersonius, based on material then thought to have come from Maryland, but later recognized as coming from Virginia (Gardner, 1943:38, 1948:201; Ward and Blackwelder, 1975:3-4; Wilson, this volume, p. 21). Harris (1937:443) apparently was the first to consider without question that three North American fossils were so represented, as reflected in the following statement: "We have often wondered by what home-returning sailor, spec- imens of Ecphora quadricostata, Pecten jeffersonius, and Venus tridacnoides were brought from our colonial shores . and published in . . Listers Historiae Conchyliorum." Lister's figure of the snail, Ecphora, has been widely regarded as the first published (supposedly in 1685) of a North American fossil, but the year and priority are cer- tainly wrong and the specific identification as E. quadricos- tata is questionable. Lister's figure is reproduced here (Fig- ure IF) along with photographs of specimens of E. quadri- costata from the Lee Creek Mine (Figure 1A-E). Say (1824:128) had speculated upon the similarity between his new species, Fusus 4-costatus, and that figured by Lister, but rejected their identity because Lister's specimen seemed to lack an umbilicus. Conrad (1864:211) however, regarded Lister's figure as representing a rare variety of the species, as he had himself found one specimen without umbilicus. Recent efforts to locate Conrad's specimen in the collections of the Academy of Natural Sciences of Philadelphia have not as yet been successful (Carol Jones, pers. comm.). The specific identification might be resolved if the original spec- imen could be found. Shattuck (1904:xxxiv) simply asserted that "in 1685, Martin Lister published a figure of Ecphora quadricostata. This was the first American fossil to be fig- ured, and the original came from the Miocene of Mary- land." Martin (1904:207, pl. 52: fig. 3) cited Lister in his synonymy of E. quadricostata and reproduced Lister's fig- ure. Vokes (1957:30, pl. 25: fig. 1) followed these authors and reproduced the figure again. Ward and Blackwelder (1975:3) were the first to point out that none of Lister's illustrations of the three North American mollusks was published as early as 1685, and that both Chesapecten jeffer- sonius and Mercenaria tridacnoides preceded Ecphora. How- ever, their assertion that the figure of Ecphora was published in 1692 seems not to be demonstrable. Available evidence indicates that it was first published in the Huddesford (1770) edition of Lister (Wilkins, 1957:204; Wilson, this volume; Robert Cross, British Museum (Natural History), pers. comm.). Conrad (1840:46; in Dall, 1893:68) agreed with Say's (1824) identification of Lister's scallop as Pecten jeffersonius, but regarded the peculiarities of the shell margin as result- ing from attachment of barnacles, rather than from abnor- mality in growth as implied by Say. Ward and Blackwelder (1975, pl. 1) and Blackwelder and Ward (1976, frontispiece) reproduced Lister's figure of Chesapecten jeffersonius, which they regarded, correctly it seems, as indeed the first illus- trated (and described, though not formally) North Ameri- can fossil. C. jeffersonius is unique among the three in that it has descriptive text both on the original plate (Figure 2 here) and in annotations written by Lister and published by Huddesford (1770), all reproduced in full (and that on the plate translated) by Ward and Blackwelder (1975:15). Conrad (1838:10; in Dall, 1893:28) apparently was the first to recognize among Lister's plates the third example of a North American fossil, the clam Venus tridacnoides, an identification accepted also by Gardner (1943:132). Wilson (1983:485) has traced the nomenclatural history of this taxon, which should now be known diS Mercenaria corrugata. Lister's figures are reproduced here as Figure 3. These North American fossils probably came into Lister's hands through much more purposive acts than a sailor's curio-collecting. Ewan and Ewan (1970:312) made a strong circumstantial case for their having been received from John Banister, who certainly sent specimens to Lister and others, and who lived and collected on the Virginia coastal plain from 1678 to 1692. Banister's untimely death fore- closed any possibility of completing his planned natural history of Virginia, which undoubtedly would have pro- vided a more nearly adequate record of his extensive con- tributions, including those in paleontology. The two bi- valves illustrated by Lister, now assigned to species of the Yorktown Formation, in all probability were collected by Banister. The Ecphora seems less certain in that its specific identity is questionable; it appeared only in one of the last supplemental plates, at least some years after Banister's death, and it is labeled in the figure as "a Marilandia." According to Druid Wilson (pers. comm.) extreme variants o{ Ecphora are to be expected in the pre-Yorktown Miocene and in Maryland, but not in the Yorktown Formation and not in Virginia. The illustrated specimen well might have been obtained by Hugh Jones who served in the ministry in Maryland from 1696 through 1701, during most of that lime in Christ Church Parish, Calvert County (Ewan and Ewan, 1970:111; Frick et al., in press; Reveal, 1984). He NUMBER 61 a. jM.arx,landxa. . J? FIGURE 1.—Ecphoras from the Atlantic Coastal Plain: A-E, Ecphora quadricostata, Yorktown Formation, Lee Creek Mine, North Carolina, approximately Xl (A, USNM 371353, and B, USNM 371352, collected by Druid Wilson from spoil heaps; c, USNM 371354, and D, USNM 371355, collected by Jack H. McLellan from spoil heaps. E, USNM 371351, collected by Peter J. Harmatuk in place in basal bed of Yorktown Formation). F, Ecphora sp., collector and formation unknown; from Maryland according to original figure caption (first published in, and reproduced at approximately original size from. Lister, Huddesford edition, 1770, pl. 1059: fig. 2). was described in 1699 by the British naturalist James Petiver as "a very curious Person in all parts of Natural History; particularly in Fossils; some of which he hath sent me from Maryland . " (Dandy, 1958:142). These may in part have been among the fossils sent in 1697 to England by Jones, apparently intended for Edward Lhwyd, but diverted to other hands, probably including those of Petiver and John Woodward (Frick et al., in press). Woodward "evidently" lent fossils to Lister for illustration (Keynes, 1981:31). Pe- tiver's friend, Dr. David Krieg, would seem to have been yet another possible source of the Ecphora, as he collected in Maryland in 1698, at least informally under the aegis of the Temple Coffee House Botany Club, which included Sloane and Lister, and later apparently prepared some of Lister's plates for engraving (Frick et al., in press). It seems not at all improbable that some or all of these historic fossils may yet be rediscovered, although thus far none of Lister s specimens has been identified positively in the Ashmolean Museum at Oxford (MacGregor, 1983; con- firmed by H.P. Powell, Oxford University, pers. comm.). Lister of course used other collections extensively, including those of the Dutchess of Portland and Sir Hans Sloane, including ultimately that of Petiver. Wilkins (1953) did not record the American fossils among Listerian shells recog- nized in the Sloane Collection, but it is not clear that he searched the paleontological holdings. However, a recent SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY o- u^q.^n^. Occ . FIGURE 2.—Chesapecten jeffersonius (Say, 1824), right valve (thought to have been collected by John Banister from the Yorktown Formation of Virginia; first published in Lister, 1687, pl. 167; reproduced at approximately original size from Huddesford edition, 1770). ■6^ NUMBER 61 4-99 FIGURE 3.—Mercenaria corrugata (Lamarck, 1818), left valve in external (above) and internal (below) aspects (thought to have been collected by John Banister from the Yorktown Formation of Virginia; first published in Lister, 1688, pl. 499; reproduced at approximately 0.8 original size from Huddesford edition, 1770). SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY search of both the modern and fossil collections of the British Museum (Natural History) did not yield Lister's Ecphora (John Cooper, British Museum (Natural History), pers. comm.) Interestingly Wilkins (1953:14) did note that "the last five plates [1055-1059] seem to have been drawn by different artists [the identity of Lister's artists and en- gravers is a special problem, discussed at length by Keynes, 1981:25-35], most ofthe specimens being from collections other than those connected with the present account." The appearance of Ecphora in one of those plates suggests a history for it later than and separate from that for Chesa- pecten and Mercenaria. Could it be the very specimen listed by Lightfoot? The specimens scarcely can be recovered through further speculation from this side of the Atlantic, but might be pursued fruitfully in England and possibly on the Continent. Meanwhile, because Lister's figures are the starting point in the study of mollusks of the Chesapeake series, and because the figures are available together in no single, recent, widely distributed publication, it seems that the present volume is a suitable place for their reproduction. Accordingly, they are presented here in Figures 1-3, with data as presently understood in the respective captions. All of the figures and their plate numbers are taken from the Huddesford edition (1770), specifically from the copy in the library of the Division of Mollusks, National Museum of Natural History, Smithsonian Institution. Of course Lister's work was pre-Linnaean, and however interesting antiquarially, had only limited relevance to North American paleontology, except as a harbinger of things to come. The superabundance of well-preserved mollusks in the deposits ofthe Atlantic Coastal Plain inevi- tably resulted in intensive and extensive research as the sciences of malacology and paleontology developed. Follow- ing close upon the pioneering work by Say (1819-1824; see Summers, 1982), Conrad began his sustained and volumi- nous flow of publications extending at least from 1830 to 1877 (see Dall, 1893, especially pages v-xiv, for proof that Conrad was a worthy successor to Lister in the arena of idiosyncratic publication). The modern era of basic descrip- tive and increasingly synthetic taxonomic work spans ap- proximately a century, and this long and strong tradition continues vigorously, as evidenced in the chapters by con- tributors to this volume, where citations to many of the writings of their predecessors may be found. The existence and progressive improvement and expansion of a broad and deep database of this kind are the indispensable prerequi- sites to addressing questions of a more theoretical or ab- stract nature, as exemplified by Blackwelder (1981), Stanley and Campbell (1981), Miyazaki and Mickevich (1982), and Kelley(1983). General acknowledgments relating to the Lee Creek proj- ect may be found in Ray (1983:9-11). With regard to this foreword, 1 wish to thank Joseph Ewan for reading and improving the manuscript; James L. Reveal for information on Hugh Jones; Carol Jones for trying to find specimens at the Academy of Natural Sciences of Philadelphia alluded to by Timothy Conrad; Stephen Keynes for responding to my letter to his father, the late Sir Geoffrey Keynes; John Cooper and H.P. Powell for information about collections at the British Museum (Natural History) and Oxford, re- spectively; Robert Cross and associates at the British Mu- seum (Natural History) for looking into publication dates of Lister; the late Joseph Rosewater for access to Historiae Conchyliorum and other rare molluscan literature; Victor E. Krantz for photographs; Lawrence B. Isham, for preparing the figures as a "rush" job on the last afternoon of his last day before retirement, after more than 30 years at the Smithsonian Institution; and Mary Parrish for modification of Figures 1 and 3. Finally, it should go without saying, but must not, that 1 have no credentials in malacology; even these historical notes are derivative. Any slight augmentation of my mini- mal layman's knowledge of the subject is to be attributed primarily to the authors of the chapters in this volume, to whom 1 am deeply indebted, both for specific assistance to me and for fortitude and patience in seeing this volume to completion. The preceding unquestionably fulfills every criterion of a foreword, with one debatable exception. If indeed it is "likely to be of interest," that results in significant part from Druid Wilson's influence. Literature Cited Allmendinger, David P., Jr. 1985. The Early Career of Edmund Ruffin, 1810-1840. The Virginia Magazine, 93(2):! 27-1.54. Blackweldei, Blake W. 1981. Late Ono/oic Marine Deposition in the United States Atlantic (loastal Plain Related to Tectonism and Global Climate., Palaeo- geography, Palaeoclimatology, Palaeoecology, 34:87-1 14. Blackwelder, Blake W., and Lauck W. Ward ] 976. Stratigraphy of the Chesapeake Croup of Maryland and Virginia. (Guidebook 7b: Northeast-Southeast Sections Joint Meeting 1976). 55 pages, frontispiece, 3 plates, 15 figures. Arlington, Virginia: Geological Society of America. Conrad, Timolhy A. 1838. Fossils of the Medial Tertiary ofthe United States, No. 1, pages xvi + 32, plates 1-17. Philadelphia: Judah Dobson. [Reprinted in Dall, 1893:1-52, plates 1-17.] 1 840. Fossils of the Medial Tertiary of the United States. No. 2, pages 33- 56, plates 18-29. Philadelphia: Judah Dobson. [Reprinted in NUMBER 61 Dall, 1893:53-80, plates 18-29.] 1864. Notes on Shells, with Descriptions of New Fossil Genera and Species. Proceedings ofthe Academy of Natural Sciences of Philadel- phia, 16:211-214. Croom, H.B. 1835. Some Account ofthe Organic Remains Found in the Marl Pits of Lucas Benners, Esq. in Craven County, N.C. American Journal of Science and Arts, 27:168-171. Dall, William Healey, editor 1893. Republication of Conrad's Fossils ofthe Medial Tertiary ofthe United States, with an Introduction by William Healey Dall. xviii + 136 pages, 49 plates. Philadelphia: Wagner Free Institute of Science Special Publication. [Also footnotes, references to plates, and index by Dall.] Dandy, J.E. 1958. The Sloane Herbarium: An Annotated List ofthe Horti Sicci Com- posing ft; with Biographical Accounts of the Principal Contributors, Based on Records Compiled by the Late James Britten, with an Introduction by Spencer Savage. 246 pages, frontispiece, 2 plates. London: British Museum (Natural History). [Page 246 followed by 96 facsimiles of handwriting of contributors to herbarium, on 32 unnumbered pages.] Dillwyn, L.W. 1823. An Index to the Historia Conchyliorum of Lister, with the Name of the Species to Which Each Figure Belongs, and Occasional Remarks. 48 pages. Oxford: Clarendon Press. Dodge, Henry 1956. A Historical Review ofthe Mollusks of Linnaeus, Part 4: The Genera Buccinum and Strombus ofthe Class Gastropoda. Bulletin of the American Museum of Natural History, 111(3): 153-312. Emmons, Ebenezer 1858. Agriculture ofthe Eastern Counties; Together with Descriptions of the Fossils of the Marl Beds. In Report of the North-Carolina Geological Survey, xvi -1-314 pages, more than 256 figures. Ra- leigh: H.D. Turner. [Reprinted in part, 1969, Bulletins of Amer- ican Paleontology, 56(249):57-230, with new index.] Ewan, Joseph, and Nesta Ewan 1970. John Banister and His Natural History of Virginia, 1678-1692. xxx -(- 486 -I- [2] pages, 9 "charts and exhibits," 70 figures. Urbana, Chicago, London: University of Illinois Press. Frick, George F., James L. Reveal, C. Rose Broome, and Melvin L. Brown In press. Botanical Explorations and Discoveries in Colonial Maryland, 1688 to 1755. Huntia, 7. Gardner, Julia 1943. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina, Part 1: Pelecypoda. United States Department of the Interior, Geological Survey, Professional Paper, 199-A:iv -1-178 pages, plates 1-23, 4 figures, 2 tables. [Published January 1944.] 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina, Part 2; Scaphopoda and Gastropoda. United States Department of the Interior, Geological Survey, Professional Paper, 199-B:iv -I- 179-310 pages, plates 24-38. Harris, Gilbert D. 1937. First Century of Progress in Cenozoic Marine Invertebrate Pa- leontology. Bulletin of the Geological Society of America, 48:443- 462. Huddesford, William 1 770. Martini Lister, M. D. Historiae sive Synopsis Methodicae Conchy- liorum .... 1059 + 22 numbered plates. Oxford, [see Keynes, 1981:43, for bibliographic details.] Kelley, Patricia H. 1983. Evolutionary Patterns of Eight Chesapeake Group Molluscs: Evi- dence for the Model of Punctuated Equilibria, yowrna/ of Paleon- tology, 57:581-598, 5 figures. Keynes, Geoffrey 1981. Dr. Martin Lister: A Bibliography. Godalming, St. Paul's Bibliog- raphies, 3: xii -f 52 pages, 18 plates. [Lightfoot, John] 1 786. A Catalogue of the Portland Museum, Lately the Property of the Duchess Dowager of Portland, Deceased: Which Will Be Sold at Auction, by Mr. Skinner and Co viii -(- 194 pages. London. [See S.P. Dance, 1962, The Authorship of the Portland Catalogue (1786). Journal ofthe Society for the Bibliography of Natural History, 4:30-34, regarding attribution to Lightfoot.] Lister, Martin 1685-1692. Historiae sive Synopsis Methodicae Conchyliorum .... 1057 + 22 numbered plates. London, [see Keynes, 1981:41, for biblio- graphic details.] MacGregor, Arthur, editor 1983. Tradescant's Rarities: Essays on the Foundation of the Ashmolean Museum, 1683, with a Catalogue ofthe Early Collections, xiv -I- 382 pages. Oxford: Clarendon Press. Martin, George C. 1904. Systematic Paleontology, Miocene, Mollusca, Gastropoda. Mary- land Geological Survey, Systematic Geology and Paleontology Report, 2:131-270, plates 39-63. [Plates with legends (pages 31-55) bound separately.] Mitchell, Betty L. 1981. Edmund Ruffin, a Biography, xii + 306 pages. Bloomington: Indiana University Press. Miyazaki, Joan M., and M. F. Mickevich 1982. Evolution of (Chesapecten (Mollusca: Bivalvia, Miocene-Pliocene) and the Biogenetic Law. In Max K. Hecht, Bruce Wallace, and Ghillean T. Prance, editors. Evolutionary Biology, 15:369-409, 6 plates, 18 figures, 6 tables. [New York and London: Plenum Press.] Olmsted, Denison 1827. Report on the Geology of North-Carolina, Conducted under the Direc- tion of the Board of Agriculture, Part II. pages 85-155. Raleigh: North Carolina Board of Agriculture. Ray, Clayton E., editor 1983. Geology and Paleontology ofthe Lee Creek Mine, North Caro- lina, 1. Smithsonian Contributions to Paleobiology, 53: 529 pages, frontispiece, 95 figures, 101 plates. Reveal, James L. 1984. Hugh Jones (1671-1702)—Calvert County Naturalist. The Cal- vert Historian, 1(2): 1-11. Sawyer, F. C. 1962. A Copy of De Cochleis and Two Copies of the Historia Conchy- liorum of Martin Lister (1638-1712). yowrna/ ofthe Society for the Bibliography of Natural History, 4:28-29. Say, Thomas 1824. An Account of Some of the Fossil Shells of Maryland, yowrna/ of the Academy of Natural Sciences of Philadelphia, 4:124-155, plates 7-13. [Reprinted, 1896, Bulletins of American Paleontology, l(5):300-346, plates 26-32.] Schroter, Johann Samuel 1783. Einleitung in die Conchylienkenntniss nach Linne, Erster Band, von den Schnecken. xxxii -I- 860 pages, 3 plates. Halle: Johann Jacob Gebauer. Shattuck, George Burbank 1904. Geological and Paleontological Relations, with a Review of Ear- lier Investigations. In William Bullock Clark, George Burbank Shattuck, and William Healey Dall, The Miocene Deposits of Maryland. Maryland Geological Survey, Systematic Geology and Pa- leontology Report, 2:xxxiii-cxxxvii. Stanley, Steven M., and Lyle D. Campbell 1981. Neogene Mass Extinction of Western Atlantic Molluscs. Nature, 293:457-459, 2 figures. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Summers, Gerald 1982. A Bibliography of the Scientific Writings of Thomas Say (1787- 1834). Archives of Natural History, 11:69-81. Tryon, George W., Jr. 1880. Manual of Conchology; Structural and Systematic, with Illustra- tions ofthe Species, Vol. 11: Muricinae, Purpurinae. 289 pages, 70 plates. Philadelphia: published by the author. Vokes, Harold E. 1957. Miocene Fossils of Maryland. Maryland Board of Natural Re- sources, Department of Geology, Mines and Water Resources Bulletin, 20:viii -(- 85 pages, 31 plates. Ward, Lauck W., and Blake W. Blackwelder 1975. Chesapecten, a New Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. United States Department of the Interior, Geological Survey, Professional Paper, 861:24 pages, 7 plates, 2 figures, 3 tables. Wilkins, Guy L. 1953. A Catalogue and Historical Account of the Sloane Shell Collec- tion. Bulletin of the British Museum (Natural History), Historical Series, l(l):l-48, plates 1-12. 1957. Notes on the Historia Conchyliorum of Martin Lister (1638-1712). Journal ofthe Society for the Bibliography of Natural History, 3:196- 205, 1 figure. Wilson, Druid 1983. The Lee Creek Enigma, Mclellania aenigma, a New Taxon in Fossil Cirrhipedia. In Clayton E. Ray, editor. Geology and Pa- leontology ofthe Lee Creek Mine, North Carolina, I.Smithsonian Contributions to Paleobiology, 53:483-498, 3 plates. Miocene Cephalopods from North Carolina William M. Furnish and Brian F. Glenister ABSTRACT Specimens representing the nautilid genus Aturia have been recovered during phosphate mining operations in North Carolina. This material consists of a few fragmentary internal molds too incomplete for specific determination. Such fossils are rare elsewhere, but comparable occurrences have been recorded throughout the world. Introduction Predecessors of living externally shelled cephalopods, represented by Nautilus, are not known from Neogene strata. Aturia is a bizarre related form in a nautilid lineage that originated about 50 million years ago in the Paleocene and became extinct during the Miocene. In a comprehen- sive survey, Stenzel (1940:734) was able to find only two references involving Miocene specimens from the entire Atlantic and Gulf Coasts. Miller (1947:110) was able to add but one occurrence, from Florida. These records included a total of only three specimens, one never studied in detail. In such a light, new discoveries from North Carolina seem worth recording. Congeneric specimens of Miocene age have been found in the Caribbean region and the Pacific Coast of the United States, and Aturia is known to have a world-wide distribution in contemporaneous strata. Never- theless, Neogene occurrences are so rare that many records are based upon single specimens found in association with an abundance of other shells. Still, there is no indication of any geographic restriction, such as that now in effect for Nautilus, which is limited essentially to Melanesia and nearby areas ofthe southwest Pacific. Although more nearly characteristic of low latitudes, Aturia has been found at 60 degrees north and 55 degrees south. Similarly, there are no clear cases of endemism in fossil species and sexual dimorph- ism has not been demonstrated. ACKNOWLEDGMENTS.—The Aturia from the Lee Creek William M. Furnish and Brian F. Glenister, Department of Geology, The University of Iowa, Iowa City, Iowa 52242. Mine were secured and made available for study by Jack H. McLellan and William D. Bennett of Texasgulf Inc. One of the specimens, found by P.J. Harmatuk, was forwarded by Clayton E. Ray, Smithsonian Institution. Their assistance is appreciated. Superfamily NAUTILACEAE De Blainville, 1825 There are fairly distinct lineages of nautilids in the late Mesozoic and Tertiary (Kummel, 1964; Shimanskii, 1962, 1975; Wiedmann, 1960). Representatives of the Hercoglos- sidae Spath, 1927, most common in the Paleogene, are relatively unspecialized; there are no fundamental differ- ences between them and some Paleozoic forms. By contrast, those in the Aturiidae differ markedly as far as suture and siphuncle are concerned. Complex sutures are known in unrelated Mesozoic forms; for example, Pseudonautilus Meek, 1876, [=?Permoceras Miller and Collinson, 1953]. The aturiid dorsal siphuncle, more nearly unique for coiled shells, is developed comparably only in a couple of Paleozoic ammonoid superfamilies. Family ATURHDAE Chapman, 1857 The well-known aturiid phylogeny may be almost as simple as it appears. Ancestral Aturoidea Vredenburg (1925:9) has been found widely distributed in strata of Paleogene age, characteristically Paleocene and lower Eocene. An even simpler relative occurring in early Paleo- cene type Danian of Faxe, Denmark, should be included in the family. Danaturoidea Rosenkranz, 1960, has been pro- posed with Nautilus fricator Beck, 1836, as type-species. This taxon is a rare associate of Hercoglossa danica (Schloth- eim, 1820), and was well illustrated by Ravn (1902, pl. 5: figs. 1,2,4). A prominent narrowly rounded ventrolateral lobe and dorsal lobe anticipate these developments in Atu- roidea. The dorsad position ofthe siphuncle is also indicative of relationship. A modern concept of typical Aturia is based upon Mio- cene material from southwestern France (Jung, 1966) and Italy (Sturani, 1958, 1959). Well preserved larger shells can be distinguished taxonomically; but most named species are based upon vagaries of preservation, size, or geography. 10 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Some apparently reached a size of a half-meter in diameter, without appreciable mature modifications. As a rule, Eocene forms have symmetry in the ventrolateral lobe re- versed from that in the Miocene. The apex of the lobe is directed away from the periphery in younger representa- tives. All differences are marginally apparent and grada- tional, so there is little practical basis for the several subge- nera that have been proposed. No aturiid can be regarded as an index fossil, except in a general sense. Genus Aturia Bronn, 1838 TYPE-SPECIES.—Nautilus aturi Basterot, 1825; subse- quent designation. Discoidal and thinly discoidal shells are included in the genus Aturia. Surface of test nearly smooth, with fine growth lines forming a rounded hyponomic sinus. Umbili- cus closed by callous within the first volution ofthe conch. Camerae normally short, with base of the angular ventro- lateral lobe in contact with preceding suture. Siphuncle is relatively large and invaginated within the narrow dorsal lobe. Aturia sp. Four specimens representing a species of Aturia have been recovered from the Pungo River Formation at Texasgulfs Lee Creek Mine, near Aurora in the Pamlico area of coastal North Carolina. All specimens are deposited in the collec- tions of the National Museum of Natural History, Smith- sonian Institution. These fossils are probably not a measure of abundance, in comparison to other known localities, but rather an evidence of diligent search in an extensive expo- sure. Cephalopod shells are relatively large and distinctive in appearance. All of these have a restored diameter of some 100 to 150 mm, normal for the genus. Only one was secured in a larger portion of matrix, and this specimen is a mere fragment of five camerae, suggesting that the shells suffered deterioration in a zone of moderately high energy. The other specimens consist of shorter segments frag- mented during excavation and picked up as free specimens (Figure 1). One has a sedimentary interface, representing a chamber only partially filled with fine silt. In all cases, the original aragonitic test has been dissolved away subsequent FIGURE I.—Aturia sp. from units 4-5 in the Pungo River Formation (Miocene) at the Texasgulf Inc Lee Creek Mine, near Aurora, Beaufort Clounty, North Carolina: A, septal view; B, lateral view; C, apertural view. This specimen is the best and largest of the cephalopods found at the locality; the complete whorl would have been slightly greater than 150 mm in diameter and about 65 mm in width. A body chamber would add an additional 100 mm of diameter. There were probably about four volutions of the complete cgique du Bassin Tertiaire du .Sud-ouest de la France, premiere partie, comprenant les observations generales sur les mollu.sques fo.ssiles, et la description particuliere de ceux qu'on rencontre dans ce bassin. Societe d'Histoire Naturelle de Paris, Memoire, 2(1); 100 pages, 7 plates. Beck, H.H. 1836, Notes on the Geology of Denmark. (Jeotogical Society of London Proceedings, 2(43):21 7-220. Brotm. H.C;. 1838. Lethaea Geognostica, oder Abhildungen und Beschreibungen der fur die Gebirgs-Formalionen bezeichnendsten Versteinerungen: Zweiter NUMBER 61 II Band, das Kreide- und Molassen-Gebirge enthaltend; pages 545- 1346. Stuttgart: E. Schweizerbart's. Jung, Peter 1966. Zwei miocaene Arten von Aturia (Nautilaceae). Eclogae Geologicae Helvetiae, 59(l):485-492, 2 plates, 1 figure. Kummel, Bernhard 1964. Nautiloidea-Nautilida. In Curt Teichert et al., Part K, Mollusca 3, Cephalopoda—General Features, Endoceratoidea-Actinocer- atoidea-Nautiloidea-Bactritoidea. In Raymond C. Moore, editor, Treatise on Invertebrate Paleontology, pages K383-K457, figures 280-337. Lawrence, Kansas: Geological Society of America and University of Kansas Press. Meek, F.B. 1876. A Report on the Invertebrate Cretaceous and Tertiary Fossils of the Upper Missouri Country. In Report ofthe United States Geolog- ical Survey of the Territories, F. V. Hayden, United States Geologist- in-charge, 9:lxiv -\- 629 pages, 45 plates, 85 figures. Miller, A.K. 1947. Tertiary Nautiloids of the Americas. Geological Society of America Memoir, 23:viii -I- 234 pages, 100 plates, 30 figures, 1 table. Miller, A.K., and C. Collinson 1953. An Aberrant Nautiloid ofthe Timor Permian, yourna/ of Paleon- tology, 27(2):293-295, 1 figure. Ravn, J.P.J. 1902. Molluskerne i Danmarks Kridtaflejringer, 11: Scaphopoder, Gas- tropoder og Cephalopoder. Det Kongelige Danske Videnskabernes Selskabs Skrifter. sjette Raekke. Naturvidenskabelig og Mathematisk Afdeling, 11(4):205-270, 5 plates, 2 figures. Rosenkrantz, Alfred 1960. Danian Mollusca from Denmark. In A. Rosenkrantz and F. Brotzen, editors. The Cretaceous-Tertiary Boundary. In Theo- dor Sorgenfrie, editor. Report of the Twenty-First Session, Norden, International Geological Congress, Copenhagen, 5(5): 193-198. Schlotheim, E.F. Baron von 1820. Die Petrefactenkunde auf ihrem jetzigen Standpunkte durch die Bes- chreibung seiner Sammlung versteinerter und fossiler Uberrete des Thier- und Pfianzenreichs der Vorwelt erlautert von E. F. Baron von Schlotheim . . . mit XV Kuptertafeln. 437 pages, plates 15-29 [in atlas]. Gotha: Becker. [Plates 1-14 were issued in 1804 with Schlotheim's Beschreibung merkwiirdiger Krduterabdrucke und Pflanzen-Versteinerungen. | Shimanskii, V.N. 1962 [1974]. Order Nautilida. In V. E. Ruzhentsev, editor, Mollusca- Cephalopoda, I: Nautiloidea, Endoceratoidea, Actinoceratoidea, Bactritoidea, Ammonoidea (Agoniatitida, Goniatitida, Clymeni- ida). In Yu. A. Orlov, editor. Fundamentals of Paleontology (Os- novy paleontologii), 5:159-226 (original pages 115-151) figures 70-142. [Translated from Russian, Israel Program for Scientific Translations, Jerusalem.] 1975. Melovye Nautiloidei. Akademiia nauk SSSR, Paleontologicheskii Institut, Trudy, 150: 208 pages, 34 plates, 26 figures, 47 tables. Stenzel, H.B. 1 940. Tertiary Nautiloids from the Gulf Coastal Plain. In Contributions to Geology, 1939, Part 2. University of Texas Publication, 3945:731-794, plates 35-42, figures 114-127, 3 tables. Sturani, Carolo 1958. 1; Nautiloidi del genere Aturia nei Bacino Terziario Ligure- Piemontese. Atti della Societa Italiana di Scienze Naturali e del Museo Civico di Storia Naturale in Milano, 97(4):362-390, plates 18-20, 9 figures. 1959. Strutture della conchiglia, del sifone e della Parte Embrionale in Aturia aturi (Bast.). Rivista Italiana di Paleontologia e Stratigrafia, Milano, 65(3): 175-202, plates 6-7, 12 figures. Vredenburg, E.W. 1925. Descriptions of Mollusca from the Post-Eocene Tertiary Forma- tion of North-western India: Cephalopoda, Opisthobranchiata, Siphonostomata. Geological Survey of India Memoir, 50(l);xii -(- 350 -I- xvi pages, 13 plates. Wiedmann, Jost 1960. Zur Systematik jungmesozoischer Nautiliden, unter besonderer BeriJcksichtigung der iberischen Nautilinae d'Orb. Palaeontogra- phica, series A, 115(1-6): 144-206, plates 17-27, 26 figures. A New Pycnodont Oyster from the Pungo River Formation, and an Annotated List of the Cenozoic Pycnodonts of the Atlantic and Gulf Coastal Plain Druid Wilson ABSTRACT Pycnodonte (Gigantostrea) leeana, new species, is described, and the Coastal Plain pycnodont oysters are listed with geologic and geographic ranges. Introduction The oysters with vesicular shell structure now commonly referred to as pycnodonts (Pycnodonteinae) have been dis- tinguished lately from other suprageneric taxa in the Ostreacea. The need for discrimination has been well dem- onstrated by the work of Ranson (1939-1941) and of Sten- zel, culminating in Stenzel (1971). Although its systematic significance may have been over- looked, vesicularity in American fossil oysters had been noted by Whitfield (1894:29) in the Miocene Ostrea per- crassa Conrad and earlier Lamarck's Gryphaea vesicularis was commonly used as a name for Cretaceous and Paleocene pycnodonts, particularly in New Jersey. The vermiculate character of the chomata (denticles) is equal in importance and usually more easily observed. Gardner (1916:572) used Pycnodonte Fischer de Waldheim as a subgenus of Gryphaea for the species vesicularis Lamarck, which she regarded as the prior name for radiata Fischer de Waldheim, the type- species of Pycnodonte. No notice was taken of the vesicular shell structure but the vermiculate form of the denticles was described. According to Stenzel (1971:1105) prismatic shell layers are absent except in the genus Neopycnodonte. Fossil pycnodonts are presently unknown in the Coastal Plain after Yorktown time, but they can be expected. Ostrea thomasi McLean (1941:7, pis. 3, 4) described from the western Atlantic is obviously a pycnodont. Its vesicular shell structure is well illustrated. It is a homonym of O. thomasii Druid Wilson, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. "Conrad" Glenn (1904:380), and according to Abbott (1954:374) it is a synonym ofthe pycnodont Ostrea hyotis L. (as recognized by Ranson (1949:451)), which is a common Recent Indo-Pacific species. Ranson reported O. hyotis from numerous Atlantic localities. The species has not been re- ported in any of the standard works on Atlantic or Carib- bean faunas except by Abbott (1954, 1974). Recently, Harry (1985:130) has renamed O. thomasi McLean as Par- ahyotissa mcgintyi and made it the type of his new genus Parahyotissa. Harry (1985:132-133) also reported Neopyc- nodonte cochlear (Poli) in the western Atlantic and Gulf of Mexico. The purpose here is to describe new species of Pycnodonte (Gigantostrea) from the middle Miocene Pungo River For- mation. Palmer and Brann (1965:149) introduced the use of Gigantostrea Sacco for some Coastal Plain pycnodonts. The figure of the type of the type-species of Pycnodonte Fischer de Waldheim, 1835 (P. radiata Fischer de Wal- dheim) is so different from that of Gigantostrea Sacco (G. gigantica (Solander) as figured by Stenzel (1971, fig. J81, 1, 2) that 1 am unable to follow Stenzel (1971:1107) in syn- onymizing Gigantostrea under Pycnodonte (Pycnodonte). ACKNOWLEDGMENTS.—Thanks are extended to Robert H. McKinney and Haruo E. Mochizuki ofthe U.S. Geolog- ical Survey for photography and prints; and to Barbara A. Bedette of the U.S. Geological Survey for preparation of the plates. Pycnodonte (Gigantostrea) leeana, new species FIGURES 1-5 DESCRIPTION.—Shell large, subcircular, not excessively thickened for the size. More or less equivalved, left valve of holotype slightly larger. Convexity irregular, more pro- nounced anteriorly; left valve of the holotype the more convex; left valve, the larger figured paratype, irregularly flattened. Exterior concentric sculpture of irregular lamel- lae and occasional concentric welts; radial sculpture of faint interrupted lines and undulations. Resilifer small and high. 13 14 SMirH.SONIAN CONTRIBUl IONS TO PALEOBIOLOGY t[(.rKKS I-).—Pyniiiddiilr (< .igiirilinlrra) Ifr/inti. new species, lioldUpe, ISNM (il7()H(). luiglil Hi null, length i 01' I rill I. llili kliess !'> I I iiilii: I L', I l^hl \.iKe; '.'>- i. lell \.il\e. NUMBER 61 15 FIGURE 5.—Pycnodonte (Gigantostrea) leeana, new species, left valve, paratype, USNM 647681, height 155 mm, length 140 mm. Adductor scar ovate and above midpoint. Chomata ver- miculate and prominent. HOLOTYPE.—USNM 647680 (both valves), height 87 mm, length 102 mm, thickness 34.4 mm (Figures 1-4); paratype: USNM 647681 (left valve), height 155 mm, length 140 nnn (Figure 5). All specimens are float with matrix like sediments ofthe Pungo River Formation. Woodring (1982:607) considered an unnamed species from the Gatun Formation (middle Miocene) of Panama to be similar to or the same as P. leeana. Specimens from a float locality in Charlotte County in southern Florida collected by Muriel Hunter are very close to P. (G.) leeana. They may be from Hunter's (1968:443) Bayshore Clay member of the Tamiami Formation said to have been named from an underwater exposure. Float specimens of species of mollusks collected in the same general area have been identified by Hunter as species now known to belong to faunal assemblages of the Eastover Formation of Virginia. The Eastover fauna is older than Yorktown but not as old as Pungo River. At any rate the Charlotte County occurrence is the last known Gigantostrea in the C>oastal Plain. Annotated List of Pycnodonts of the Atlantic and Gulf Coastal Plain There are 12 named, valid species and four unnamed species of pycnodont oysters in the Cenozoic of the Coastal Plain. Other names are synonyms, and still others are ex- pedient uses of non-Coastal Plain species names. Palmer and Brann (1965) has been an indispensable source of 16 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY information, and the same Paleocene and Eocene species have been well figured by Toulmin (1977). Ranson (1941 [ 1939-1941 ]:63-64) apparently was first to recognize several of the Coastal Plain species as pycnodonts. It is not known why Ranson (1941[1939-1941]:64) considered O. vomer Morton and O. thirsae Gabb to be pycnodonts. These species are currently allocated respectively to the genera Gryphaeostrea and Odontogryphaea, neither of which is clas- sified as pycnodont by Stenzel (1971). Original descriptions, synonymies, and diagnoses of generic-group names are pre- sented in detail in Stenzel (1971:1105-1114) and need not be repeated here. The Coastal Plain species are subsumed under the generic-group names listed below. GENERIC-GROUP NAMES Pycnodonte (Phygraea) Vyalov (1936:19) Type: Pycnodonte (Phygraea) pseudovesicularis (Giimbel, 1861). According to Stenzel (1971:1107), this is the prior name for the originally designated type, Phygraea fraus- cheri Vyalov (= Ostrea escheri Frauscher, 1886, non Mayer- Eymar, 1876). Cretaceous-Miocene according to Stenzel (1971:1107). Pycnodonte (Gigantostrea) Sacco (1897:14) Type: Gigantostrea gigantica (Solander), by original des- ignation. Lower Eocene-Miocene in the Coastal Plain. Neopycnodonte (Neopycnodonte) Stenzel (1971:1109) Type: Neopycnodonte cochlear (Poli), by original designa- tion. Eocene-Recent. Neopycnodonte (Costellata) Garcia and Levy (1983:283, pl. 1: figs. 1-5) No type designated, but proposed to receive specimens from the late Tertiary of Argentina identified as Ostrea alvarezii d'Orbigny, 1832. The taxon may be represented by an unnamed species in the Yorktown Formation of Virginia. Hyotissa Stenzel (1971:1107) Type: Hyotissa hyotis (L.), by original designation. Upper Cretaceous-Recent, according to Stenzel. SPECIFIC-GROUP NAMES Specific names that have been applied to pycnodonts of the Coastal Plain are here listed alphabetically, with com- mentary. Those believed to represent valid Cenozoic species are preceded by an asterisk (*). alabamiensis (Lea), Pycnodonte Lea. 1833:91. Ward et al. (1979:29, 31) have used Lea's name for an Eocene species from South Carolina. I have not seen Lea's holotype (monotype), but the original figure (Lea, 1833, pl. 3: fig. 71) exhibiting nonvermicu- late chomata, and Harris' description (1919:8) ofthe type as "thin and pearlaceous," and Palmer and Brann's syn- onymy (1965:111) seem to preclude use ofthe name and classification as a pycnodont. Stenzel, et al. (1957:97) have used the name as a Crassostrea. Presumably the South Carolina specimens are pycnodonts. antiguensis Brown, Ostrea Brown, 1913:603, 614, pl. 19: fig. 7, pl. 20: figs. 1, 5, 6. See new species, Hyotissa (Subgenus?) * bryani (Gabb), Pycnodonte (Phygraea) Gabb, 1877:321. Paleocene (Vincentown Fm)-middle Eocene (Manasquan Fm and Shark River Fm), New Jer- sey. According to Palmer and Brann (\96b:2?>0)precedens and glandiformis, both of Whitfield (1885), are synonyms. P. bryani and P. glandiformis were recognized as pycno- donts by Ranson (1941 [1939-1941]:63). * dissimilaris (Weller), Pycnodonte (Phygraea) Weller, 1907:453, pl. 46: figs. 2, 3. Paleocene, New Jersey (Hornerstown Fm) and North Carolina (Beaufort Fm) (Wilson et al., 1972:129). Earlier writers on the New Jersey fauna used vesicularis Lamarck as a name for this species and Clark and Martin's figures (1901, pl. 50: figs. 6, 6a) of vesicularis from Maryland are the same. glandiformis Whitfield, Ostrea Whitfield, 1885:205, pl. 27: figs. 1-5. See bryani (Gabb). * haitensis (Sowerby), Hyotissa Sowerby, 1850:53. Early Miocene (Chipola Fm, Florida)- late Miocene or Pliocene (Yorktown). Woodring (1982:607-610) detailed the occurrences in Tropical America and Florida. Specimens from Black Rock, Cape Fear River, North Carolina, occur with a Yorktown as- semblage. According to Olsson and Petit (1964:531) both tamia- miensis and monroensis of Mansfield (1932) are synonyms. They have also placed Ostrea meridionalis Heilprin in the synonymy of haitensis. O. meridionalis was described from the Caloosahatchee River as a part of the Caloosahatchee (Pliocene) fauna (Heilprin, 1886-1887:31, 100, 103). Dall (1898:686) placed meridionalis in the synonymy of O. sculpturata Conrad, a moderately large plicate nonpyc- nodont oyster. I have examined the better preserved specimen of Heilprin's two figured syntypes of Ostrea meridionalis; it exhibits the vesicular shell structure of pycnodonts in one small worn area of the exterior. This left valve (Heilprin, 1886 [1886-1887], pl. 14, fig. 35a) called holotype by Olsson and Harbison (1953:51, pl. 4, figs. 3, 3a) is here designated lectotype. This is in accord with Recommendation 74A of the 1985 International Code of Zoological Nomenclature (third edition). Rich- ards (1968:65) has cited the well-preserved syntype as "type." Heilprin's specimen undoubtedly came from a facies of the Tamiami Fm, which underlies the Caloosa- hatchee Fm along the Caloosahatchee River. The fauna of this facies includes Ecphora quadricostata (Say), Ostrea compressirostra Say (O. disparilis Conrad of authors), and Discinisca lugubris (Conrad), all species characteristic of beds of Yorktown age. NUMBER 61 17 Although Hyotissa haitensis has the greatest range in time of any Coastal Plain pycnodont, it is stratigraphically useful. It is not known to occur in strata of an age later than Yorktown time, i.e., the Pinecrest Fm of southern Florida and the Jackson Bluff Fm of western Florida. In an involved use of the names Ostrea tamiamiensis Mansfield and O. tamiamiensis monroensis Mansfield, Ep- pert (1966:58-59) has overlooked the fact that beds of both Tamiami and Chipola ages are present in the Sara- sota area. This is reflected in his faunal lists, which are biostratigaphic faunal mixtures, treated as faunal assem- blages. Hyotissa haitensis occurs in beds of both ages. * leeana, Pycnodonte (Gigantostrea), new species See page 13. * ludoviciana (Harris), Hyotissa (Subgenus?) Harris, 1919:14, pl. 10: figs. 1-10. The range may be middle Eocene (Claiborne) of Louisiana only: Palmer and Brann (1965:26) have queried the Jackson Eocene occur- rence given by Harris (1946, pl. 2: fig. 7). Discrimination of the vicksburgensis-mortoni-ludoviciana species complex is so difficult that ranges cannot be accepted as final until the complex has been studied carefully. Ward et al. (1979:29) have listed ludoviciana (as Pycnodonte) from the middle Eocene Santee Limestone of South Carolina. Pre- vious workers (Gabb, 1861; Harbison, 1944) have re- ported mortoni from the Santee (see mortoni Gabb). meridionalis Heilprin, Ostrea Heilprin, 1886[ 1886-1887]: 100, pl. 14: fig. 35. See hai- tensis (Sowerby). monroensis Mansfield, Ostrea tamiamiensis Mansfield, 1932:46, pl. 14: fig. 2, pl. 15: figs. 1-4. See haitensis (Sowerby). * mortoni (Gabb), Hyotissa (Subgenus?) Gabb, 1861:329. This name was proposed by Gabb for specimens from the Eocene of South Carolina and from Alabama; he also referred to a specimen figured by Morton (1834, pl. 19: fig. 10) as Ostrea, "var. from Alab." This specimen was regarded as "Gabb's type" by Harris (1946, pl. 1: fig. 15) and Palmer and Brann (1965:27), but Richards (1968:67) has considered the "types" to be from South Carolina. The Alabama occurrence is listed as "Eocene probably upper" by Palmer and Brann. If the species occurs in South Carolina, it is probably in the middle Eocene Santee Limestone. In the absence of spec- imens or figures of specimens from South Carolina, it is not possible to make decisions. Harbison's figured frag- ment (1944, pl. 3: fig. 5) is too poor to be definitive. The species was recognized as a pycnodont by Ranson (1941[1939-1941]:64). panda Morton, Ostrea Morton, 1834:51, pl. 3: fig. 6, pl. 19: fig. 10. According to Palmer and Brann (1965:26) this name has been used for specimens of Hyotissa (Subgenus?) mortoni (Gabb). It is a valid Cretaceous species. pandaeformis Gabb, Ostrea Gabb, 1861:328. See trigonalis (Conrad). * paroxis (Dockery), Hyotissa? Dockery, 1982:53, pl. 17: fig. 13, pl. 59: fig. 10, pl. 60: figs. 1-3. Oligocene Vicksburg group of Mississippi. Dockery has documented the source of the name as Leseur's unpublished manuscript. The description and type material are Dockery's. The pycnodont characters have been described by Harry and Dockery (1983:9). A species of pycnodont common in the Oligocene of the Superior Stone Co. quarry. New Bern, North Carolina, probably belongs to this species. * percrassa (Conrad), Hyotissa Conrad, 1840:50, pl. 25: fig. 1. Middle Miocene, Mary- land (Calvert Fm) and New Jersey (Kirkwood Fm). Palmer and Brann (1965:149) have noted Dall's misuse (1898:683) ofthe name for Eocene oysters. The vesicular structure of the species was noted as early as 1894 by Whitfield (1894:29). Ranson (1941[1939-1941:64) rec- ognized it as a pycnodont. * podagrina (Dall), Hyotissa Dall, 1896:22; 1898, pl. 30: figs. 5, 6. Upper Eocene ("Ocala Fm"), Florida. Palmer and Brann (1965:236) have documented the Eocene as determined by Forami- nifera associated with the type-specimen; and that the "Oligocene" of Dall (1898, pl. 30: figs. 5, 6) and the Miocene ("Chipola Formation") of Gardner (1926:42, pl. 10: figs. 5, 6) are erroneously applied to the type-speci- men. Recognziedas a pycnodont by Ranson (1941[1939- 1941]:64). See new species, Hyotissa (Subgenus?), for rec- ords of erroneous usages. precedens Whitfield, Gryphaea bryani, var. Whitfield, 1885:194, pl. 26: figs. 7, 8. See bryani (Gabb). queteleti Nyst, Ostrea See new species, Pycnodonte (Phygraea). I have had no success in finding the original reference of ''Ostrea quete- leti Nyst 1853" of authors, a European species. *sylvaerupis (Harris), Pycnodonte (Gigantostrea) Harris, 1897:230, pis. 4, 5, pl. 6: figs. 3, 3a, 4. Lower Eocene (Sabine), Alabama and Louisiana, according to Palmer and Brann (1965:149). tamiamiensis Mansfield, Ostrea Mansfield, 1932:46, pl. 14: figs. 1, 3. See haitensis (Sow- erby). *trigonalis (Conrad), Pycnodonte (Gigantostrea) Conrad, 1854:289, pl. 14: fig. 10 (reprinted 1939:359, pl. 23: fig. 10). Upper Eocene (Jackson), Mississippi and Alabama. Jackson age established by Harris (1946:21- 24). Perhaps no pycnodont species name has been so widely used and misused. Glenn (1904:381, pl. 101, figs, la, lb) used the name for a form of percrassa. Lately Harry and Dockery (1983:9) have extended the range downward into "the Gosport Sand ofthe upper Claiborne Group," by reidentifying forms earlier figured by Dock- ery (1977:118, pl. 22: figs. 6a, 6b, 7) as a "variation" of P. trigonalis. Kellum (1926:17) and Cooke and MacNeil 18 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY (1952:25) u.sed the name for a nonpycnodont species from a bed at Pollocksville, North Carolina, now known to be Oligocene in age. According to Palmer and Brann (1965:149) pandaeformis (Gabb, 1861) and tuomeyi (Con- rad, 1865) are synonyms of trigonalis. Cooke's trigonalis (1926, pl. 96: fig. 3) apparently is P. podagrina (Dall). Palmer and Brann (1965:150) have documented the mis- use ofthe name for Miocene species by various authors. P. trigonalis was recognized as a pycnodont by Ranson (1941[1939-1941]:64). tuomeyi Conrad, Ostrea C>onrad, 1865:184. See trigonalis (Conrad). vesicularis Lamarck, Gryphaea Lamarck, 1806:160. See dissimilaris (WeWer). '-^'-vicksburgensis (Conrad), Hyotissa (Subgenus?) Conrad, 1847:296. Palmer and Brann (1965:27) have characterized as "vicksburgensis variations' published Eocene occurrences of this species, thus effectively limit- ing the name to Oligocene occurrences. The species has been reported in the Oligocene of Alabama, Arkansas, Georgia, and Louisiana, as well as its type occurrence at Vicksburg, Mississippi; also Oligocene of Mexico (Gard- ner, 1945:83). The species was recognized as a pycnodont by Ranson (1941[1939-1941]:64). UNNAMED SPECIES new species, Hyotissa (Subgenus?) Lower Miocene (Edisto Fm), Edisto River, South Caro- lina. Sloan's (1908:470-472) "Edisto Phase' [not "Marl"] has been resurrected by Ward et al. (1979:26) as the Edisto Formation. Sloan (1908:471) noted this species as ''Ostrea haitiensis"; Cooke (1936:86) and later Cooke and MacNeil (1952:26) called it podagrina. MacNeil (in Malde, 1959:26, 27) referred to it as Ostrea sp. aff.? O. antigueyisis Brown, saying that it belonged to the panda- podagrina-vicksburgensis group. This is not the same as the small or poorly preserved specimens identified by Mansfield (1937:204) as Ostrea aff. 0. antiguensis from the Oligocene of Florida nor as Ostrea sp. cf. O. antiguensis from the Oligocene of Mississippi (Mansfield 1940:187). new species, Neopycnodonte Lower Eocene (Tuscahoma Formation), Marengo County, Alabama (USGS 15194 and 15478). Identified by Harold Harry. new species, Neopycnodonte (Costellata) An undescribed species in the Yorktown Formation of Virginia and at Lee Creek, North Carolina, apparently belongs to Costellata Garcia and Levy, described from the late Tertiary of Argentina. This new species may or may not be the same as the Pycnodonte sp. figured by Ward and Blackwelder (1980, pl. 4: figs. 3, 4) and Blackwelder (1981, pl. I: fig. 8). new species, Pycnodonte (Phygraea) Oligocene (Cooper Marl), South Carolina. Identified as "O. n. sp. aff. O. queteleti Nyst" by MacNeil (in Malde, 1959:15, 20) a pycnodont widespread in the Oligocene of Europe. This is the last occurrence in the Coastal Plain ofthe lineage of species with incised radiate lines on the right valve. Literature Cited Abbott, R.T. 1954. American Seashells. First edition, 541 pages, 39 plates, 100 figures. New York: D. van Nostrand Co. 1974. American Seashells. .Second edition, 663 pages, 24 plates, 6405 figures. New York: van Nostrand Reinhold Co. Blackwelder, B.W. 1981. Late Cenozoic Stages and Molluscan Zones ofthe U.S. Middle Atlantic Coastal Plain. Paleontological Society Memoir, 12: 34 pages, 10 plates, 9 figures, I table. Brown, A.P. 1913. Notes on the Geology of the Island of Antigua. Proceedings ofthe Academy of Natural Sciences of Philadelphia, 65:584-616, plates 18-20. Clark, W.B.,andC;.C. Martin 1901. Systematic Paleontology, Eocene, Mollusca. Maryland Geological Survey, Systematic Geology and Paleontology Report, 1:122-203, 269-309, plates 17-57. Conrad. T.A. 1840. Fossils ofthe Medial Tertiary ofthe United Slates, No. 2, pages 33- 56, plates 18-29. Philadelphia: Judah Dobson. 1 84 7. Observations on the Eocene Formation, and Descriptions of One Hundred and Five New Fossils of That Period, from the Vicinity of Vicksburg, Mississippi; with an Appendix. Proceedings of the Academy of Natural Sciences of Philadelphia, 3(11):280-299 [Re- printed 1848, with plates, in Journal of the Academy of Natural Sciences of Philadelphia, second series, 1(2):1 1 1-134, plates 11- 14.1 1854. Fossil Testacea of the Tertiary Greensand Marl-bed of Jackson, Mi.ss. In B.L.C. Wailes, Report on the Agriculture and Geology of Mis.sissippi, 289, plates 14-17. [Reprinted 1939, in Bulletins of American Paleontology, 24(86):352-359, plates 23-26 (also num- bered plates 1-4).) 1 865. Observations on American Fossils, with Descriptions of Two New Species. Proceedings ofthe Academy of Natural Sciences of Philadel- phia, 17(4): 184. Cooke, C.W. 1926. I'lie Ceno/.oic Formations. Alabama Geological Survey Special Re- port, 14:251-297, plates 93-97. 1936. (k'ology of the Coastal Plain of South Carolina. United States Geological Survey Bulletin, 867: 196 pages, 18 plates, 2 figures. Cooke, C.W.. and F.S. MacNeil 1952. Tertiary Stratigraphy of South Carolina. United States Geological Survey Professional Paper, 243-B: 19-29, 1 figure. Dall, W.H. 1896. Diagno.ses of New Tertiary Fossils from the Southern United NUMBER 61 19 States. Proceedings of the United Slates National Museum, 18(1035):2l-46. 1898. Contributions to the Tertiary Fauna of Florida with E.special Reference to the Silex Beds of Tampa and the Pliocene Beds of the Caloosahatachie River Including in Many Cases a Complete Revision ofthe Generic Groups Treated of and Their American Tertiary Species. Transactions ofthe Wagner Free Institute of Science of Philadelphia, 3(4):571-948, plates 23-35. Dockery, D.T., 111 1977. Mollusca ofthe Moodys Branch Formation, Mississippi. Missis- sippi Geological, Economic and Topographical Survey Bulletin, 120: 212 pages, 28 plates. 1982. Lower Oligocene Bivalvia ofthe Vicksburg Group in Mississippi. Mississippi Department of Natural Resources, Bureau of Geology Bulletin, 123: 261 pages, 62 plates [-1-15 unnumbered plates], 48 figures, 1 table. Eppert, H.C, Jr. 1966. Stratigraphy ofthe Upper Miocene Deposits in Sarasota County, Florida. Tulane Studies in Geology, 4(2):49-61, figures 1-2. Fischer de Waldheim, Gotthelf 1835. LettreaM. le Baron de Ferussac sur quelques genres de coquilles du Museum Demidoff et en particulier sur quelques fossiles de la Crimee. Bulletin de la Societe Imperiale des Naturalistes de Moscou, 8:101-124, plates 1-5. Gabb, W.M. 1861. De.scription of New Species of Cretaceous Fossils from New Jersey, Alabama and Mississippi. Proceedings of the Academy of Natural Sciences of Philadelphia, 13:318-330. 1877. Notes on American Cretaceous Fossils, with Descriptions of Some New Species. Proceedings of the Academy of Natural Sciences of Philadelphia. 28:276-324, plate 17. Garcia, Elsa R.De, and Regina Levy 1983. El genero Neopycnodonte Stenzel (Mollusca, Ostreina) en Repu- blica Argentina. Asociacion Geologica Argentina Revista, 38(2):283-285, plate 1. Gardner, J.A. 1916. Systematic Paleontology, Upper Cretaceous, Mollusca. Maryland Geological Survey, Systematic Geology and Paleontology Report, 6:371-733, 908-941, plates 12-45. [Text through page 578 bound separately.] 1926. The Molluscan Fauna ofthe Alum Bluff Group of Florida, Part I: Prionodesmacea and Anomalodesmacea. United States Geologi- cal Survey Professional Paper, 142-A: 79 pages, 15 plates. 1945. Mollusca of the Tertiary Formations of Northeastern Mexico. Geological Society of America Memoir, 11: 332 pages, 28 plates, 1 figure, 6 tables. Glenn, L.C. 1904. Systematic Paleontology, Miocene, Mollusca, Pelecypoda. Mary- land Geological Survey, Systematic Geology and Paleontology Report, 2:274-401, plates 65-108. [Plates with legends (pages 57-100) bound separately.] Harbison, Anne 1944. Mollusks from the Eocene Santee Limestone, South Carolina. Academy of Natural Sciences of Philadelphia, Notulae Naturae, 143: 12 pages, 4 plates. Harris, G.D. 1897. The Lignitic Stage, Part I: Stratigraphy and Pelecypoda. Bulletins of American Paleontology, 2(9):193-294, plates 1-14. [Plates also numbered 7-20.] 1919. Pelcypoda of the St. Maurice and Claiborne Stages. Bulletins of American Paleontology, 6: 268 pages, 59 plates. 1946. Part 1: Bivalves. In G.D. Harris and K.V.W. Palmer, The Mol- lusca of the Jackson Eocene ofthe Mississippi Embayment (Sabine River to the Alabama River). Bulletins of American Paleontology, 30(117): 14-206, plates 1-25. Harry, H.W. 1985. Synopsis of the Supra.specific Classification of Living Oysters (Bivalvia: Gryphaeidae and Ostreidae). The Veliger, 28(2): 121- 158, 30 figures, 3 tables. Harry, H.W., and D.T. Dockery, 111. 1983. Notes on the Lower Oligocene Oysters of Mississippi. Mississippi Geology, 4(2):7-14, 6 figures. Heilprin, Angelo 1886-1887. Explorations on the West Coast of Florida and in the Okeechobee Wilderness. Transactions ofthe Wagner Free Institute of Science of Philadelphia, 1: 134 pages, 21 plates. [Pages 65-127 i.ssued in advance with title page dated 1886; two unnumbered plates follow pages 34 and 64.] Hunter, M.E. 1968. Molluscan Guide Fossils in Late Miocene Sediments of Southern Florida. Gulf Coast Association of Geological Societies, Transactions, 18:439-450, figures 1-5. Kellum, L.B. 1926. Paleontology and Stratigraphy of the Castle Hayne and Trent Marls in North Carolina. United States Geological Survey Profes- sional Paper, 143: 56 pages, 1 1 plates, 1 figure. Lamarck, J.B.P.A. de Monet de 1806. Memoires sur les fossiles des environs de Paris, comprenant la determination des especes qui appartiennent aux animaux marins sans vertebres, et dont la plupart sont figures dans la collection des velins du Museum. Annales du Museum National d'Histoire Naturelle, 8:77-79, 156-166, 347-355, 383-388, 461-469, plates 8-14. [Reprinted 1978 by Paleontological Research Insti- tution, Ithaca, New York.] Lea, Isaac 1833. Contributions to Geology. 227 pages, 6 plates. Philadelphia. Malde, H.E. 1959. Geology of the Charleston Phosphate Area, South Carolina. United States Geological Survey Bulletin, 1079: 105 pages, 10 plates, 1 3 figures, 5 tables. Mansfield, W.C. 1932. Pliocene Fossils from Limestone in Southern Florida. United States Geological Survey Professional Paper, 170-D:43-56, plates 14-18. 1937. Mollusks of the Tampa and Suwannee Limestones of Florida. Florida Department of Conservation, Geological Bulletin, 15: 334 pages, 21 plates. 1940. Mollusks of the Chickasawhay Marl. Journal of Paleontology, 14(3):171-226, plates 25-27. McLean. R.A. 1941. The Oysters of the Western Atlantic. Academy of Natural Sciences of Philadelphia, Notulae Naturae, 67: 14 pages, 4 plates. Morton, S.G. 1834. Synopsis ofthe Organic Remains ofthe Cretaceous Group ofthe United States, i-vi -I- 7-88 + 8 -I- [8] pages, 19 plates. Philadelphia: Key & Biddle. OLsson, A.A., and A. Harbison 1953. Pliocene Mollusca of Southern Florida, with Special Reference to Those from North Saint Petersburg. Academy of Natural Sci- ences of Philadelphia Monograph, 8: 457 pages, 65 plates, 2 figures. Ols-son, A.A., and R.E. Petit 1964. Soine Neogene Mollusca from Florida and the Carolinas. Bulletins of American Paleontology, 47(217):505-574, plates 77-83. Palmer, K.V.W., and D.C. Brann 1965. Catalogue of the Paleocene and Eocene Mollusca of the Southern and Eastern United States, Part I: Pelecypoda, Amphineura, Pteropoda, Scaphopoda, and Cephalopoda. Bulletins of American Paleontology, 48(218): 1-466, plates 1-3. 20 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Ranson, Gilbert 1939-1941. Les Huitres et le calcaire; 1: Formation et structure des "chambres crayeuses," Introduction a la revision du genre Pyc- nodonta F. de W. Bulletin du Museum National d'Histoire Naturelle (Paris), second series, 11(5)[1939]:467-472; 12(7)(1940]:426- 432. figures 1-2; 13(l)[1941]:49-66, figure 1, plate 1. 1949. Note sur la repartition geographique des Ostreides du genre Pycnodonta F. de W. Bulletin du Museum National d'Histoire Na- turelle (Paris), second series, 21(4):447-452. Richards, H.C. 1968. Catalogue of Invertebrate Fossil Types at the Academy of Nat- ural Sciences of Philadelphia. Academy of Natural Sciences of Philadelphia Special Publication, 8: 122 pages. Sacco, Federico 1897. / molluschi dei terreni Terziarii del Piemonte e della Liguria, Part 23, Pelecypoda (Ostreidae, Anomiidae e Dimyidae). 66 pages, 11 plates. Torino: Carlo Clausen. Sloan, Earle 1908. Catalogue of the Mineral Localities of South Carolina. South Carolina Geological Survey Bulletin, series 4, 2: 505 pages. [Re- printed 1963 by South Carolina Division of Geology.] Sowerby, G.B. 1850. Descriptions of New Species of Fossil Shells Found by J.S. Heni- ker, Esq. Geological Society of London (Quarterly Journal, 6:44-53, plates 9-10. Stenzel, H.B. 1971. Oysters. Treatise on Invertebrate Paleontology, Part N: Mollusca 6, Bivalvia, 3:953-1224, 153 figures. Stenzel, H.B., E.K. Krause, and J.T. Twining 1957. Pelecypoda from the Type Locality of the Stone City Bedi (Middle Eocene) of Texas. University of Texas Publication, 5704: 237 pages, 22 plates. Toulmin, L.D. 1977. Stratigraphic Distribution of Paleocene and Eocene Fossils in the Eastern Gulf Coast Region. Alabama Geological Survey Monograph, 13(1): 602 pages, 72 plate.s, figures 1-29, tables 5-10; 13(2): figures 30-37, tables 1-4. Vyalov, O.S. [often as O.S. Vialov] 1936. Sur la cla.ssification des huitres. Comptes Rendus (Doklady) de I'Academie des Sciences de I'URSS, new series, 4(13), 1 (105): 17- 20. Ward, L.W., and B.W. Blackwelder 1980. Stratigraj^hic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group, Middle Atlantic Coastal Plain. United States Geological Survey Bulletin, 1482-D: 61 pages, 5 plates, 25 figures. Ward, L.W., B.W. Blackwelder, G.S. Gohn, and R.Z. Poore 1979. Stratigraphic Revision of Eocene, Oligocene, and Lower Miocene P'ormations of South Carolina. South Carolina Geological Survey Geologic Notes, 23(l):2-32, figures 1-10. Weller, Stuart 1907. A Report on the Cretaceous Paleontology of New Jersey Based upon the Stratigraphic Studies of George N. Knapp. New Jersey Geological Survey Paleontology Series, 4: 1 107 pages, 1 1 1 plates. Whitfield, R.P. 1885. Brachiopoda and Lamellibranchiata of the Raritan Clays and (ireensand Marls of New Jersey. United States Geological Survey Monograph, 9: 338 pages, 35 plates. [Also printed 1886 as New Jersey Geological Sumey Paleontology, 1.] 1894. Mollusca and (>rustacea of the Miocene Formations of New Jersey. United States Geological Survey Monograph, 24: 195 pages, 24 plates. Wilson, Druid, W.C. Blow, (and R.H. Bailey] 1972. Paleocene in Outcrop in North Carolina. In Geological Survey Re.search 1972. United States Geological Survey Professional Paper, 800-A:l29. [Bailee's name omitted by editorial oversight.] Woodring, W.P. 1982. (ieology and Paleontology of Canal Zone and Adjoining Parts of Panama: Description of Tertiary Mollusks (Pelecypods: Propea- mussiidae to C^uspidariidae; Additions to Families Covered in P306-E; Additions to Gastropods; Cephalopods.) United States Geological Survey Professional Paper, 306-F:541-759, plates 83- 124. Species of Ecphora, Including the Subgenus Stenomphalus, in the Pungo River Formation Druid Wilson ABSTRACT Published references to the genus Ecphora and the subgenus Stenomphalus and their species are summarized, including American and European stratigraphic and geo- graphic occurrences. Ecphora "quadricostata" ofthe Mary- land St. Marys Miocene is here named Ecphora (Ecphora) gardnerae and two other new species, Ecphora (Ecphora) pamlico and Ecphora (Stenomphalus) aurora are described from the Middle Miocene Pungo River Formation. E. (S.) aurora is noted in both America and Europe. Introduction Specimens of the species of the gastropod genus Ecphora have long engaged the interest of naturalists and collectors alike. In areas where they are available ecphoras are second only to shark teeth as fossils of interest to the public. Perhaps no American fossil has been so widely illustrated, particu- larly copies of Ecphora ''quadricostata" figured by Martin in the Maryland Geological Survey Miocene volume in 1904. It has been claimed that Ecphora quadricostata was the first American fossil to be illustrated (Shattuck, 1904:xxxiv; Vokes, 1957:30; Raup, 1961:606). As pointed out by Harris (1937:443) and also noted by Ward and Blackwelder (1975:3), three extinct Tertiary species, Chesapecten jeffer- sonius, Mercenaria "tridacnoides," and the Ecphora are all illustrated in Lister's Historiae Conchyliorum. The various parts of Lister's two editions of his work were published between 1685 and 1697 and the Huddesford edition in 1770. According to the findings of Engelmann (1846:461) and Wilkins (1957:203-204), no claim to priority can be made for Lister's figure of Ecphora; the plate on which it appears was not published until 1770 in the Huddesford edition. One hesitates, but the figure representing Chesa- pecten jeffersonius, published in the first edition of Lister in Druid Wilson, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. liber III in 1687 (pl. 167), apparently is first; a close second is Mercenaria "tridacnoides" in the appendix to liber III (Lister, 1688, pl. 499). Discovery in North America of specimens of new species of Ecphora (Ecphora), and of Ecphora ( Stenomphalus) (until now known only in the Miocene of Europe), are of great interest, and their probable relationships with European species are also possibly of great significance. Three species of Ecphora occur in the Pungo River For- mation: Ecphora (Ecphora) tricostata Martin, and the two new species, Ecphora (Ecphora) pamlico and Ecphora (Sten- omphalus) aurora. Only Ecphora tricostata has been collected in place, as reported by Gibson (1967:639, fig. 4). Never- theless, the matrix associated with the specimens indicates that each species occurs in a separate bed. According to Gibson, E. tricostata occurs in unit 7 at the top ofthe Pungo River Formation. Gibson (pers. com.) considers that the matrix of limestone with considerable phosphate grains associated with a float specimen of E. tricostata may indicate that it came from as low as unit 5. He believes that the small pebble-sized phosphate in the matrix associated with speci- mens of Ecphora pamlico is characteristic of beds lower than unit 5, but not as low in the section as the thoroughly phosphatized matrix of the specimens of Ecphora (Stenom- phalus) aurora. E. (S.) aurora may also occur in the Burdi- galian and Helvetian Miocene in France. I believe that Cossmann and Peyrot (1924:534-536, pl. 14: fig. 47, pl. 15: fig. 19) have misidentified this species as Ecphora mou- linsii (Brochon, 1849:117-128, figs. 1, 2), a strikingly dif- ferent species named from type Burdigalian at Leognan, France. It is interesting that Ecphora (Ecphora) jauberti (Grateloup, 1840, pl. 1: figs. 3, 4), a very rare European species related to E. (E.) pamlico, occurs in the Tortonian Miocene of Saubrigues, France, according to Cossmann and Peyrot (1924:534). If this is so, then E. (E.) jauberti occurs later than E. (S.) aurora in France, just as the closely related E. (E.) pamlico apparently does at Lee Creek. No particular significance can be placed on these possible temporal-stra- tigraphic relationships until pamlico and aurora are collected in place in America and the rare jauberti is recollected in France. Cossmann and Peyrot (1924:534-535) reported 21 22 SMITHSONIAN CONTRIBU IIONS TO PALEOBIOLOGY that the type specimen of E. jauberti (Grateloup) is lost and no other specimens have been collected. ACKNOWLEDGMENTS.—My appreciation is tendered to Jack H. McLellan and Royal Mapes without whose collecting this paper would never have been written, to Robert H. McKinney and Haruo Mochizuki of the U.S. Geological Survey for the excellent photographs and prints, and to Barbara Bedette for ever ready and timely aid. I am espe- cially grateful to Dr. Elizabeth Kuster-Wendenburg of the Naturkundemuseum, Kassel, Germany, for her early re- sponse to my request for information about the type-species of the subgenus Stenomphalus. I thank Dr. Karl Kleemann of Naturhistorisches Museum Wien, Austria, for a xerox of a part of a very rare publication. Genus Ecphora Conrad, 1843 Ecphora Conc'dd, 1843:310. TYPE-SPECIES.—Fusus 4-costatus S2iy (\^2A:\21 ,'p\. 7: fig. 5); by monotypy. Say's protograph is of the species found in the Yorktown Formation of Virginia. Sohl (1964:173) characterized the genus Ecphora as small to moderately large subfusiform shells and a moderately low spire. Whorls strongly shouldered, with strong spiral carinations over periphery; ba.sal constriction strong. Whorls may be loosely attached. Aperture ovate, produced to a narrow, generally elongate and curving siphonal canal terminating in a moderately strong notch; outer lip crenulate; inner lip moderately thick, free or partly attached over parietal surface. Umbilicus broad, open, deep, and margined by a serrate strong carina. Shells of Ecphora consist of two layers; a thick outer translucent brown layer and a thinner light-colored inner layer, which is sometimes leached away. Zalman Altschuler (pers. com.) ofthe U.S. Geological Survey has determined by x-ray identification that the outer layer of specimens of E. quadricostata and E. gardnerae is almost entirely calcite and the inner layer entirely aragonite. Aragonite, being less stable, is often leached away, as in the numerous specimens of Ecphora quadricostata from the Yorktown Formation at Lee Creek. Ecphora tricostata Martin (1904:209, pl. 52: figs. 5, 6) occurs in the Miocene Calvert Formation (rarely in the Choptank) in Maryland and in the Pungo River Formation in North Carolina. Some species not originally referred to the genus Ecphora are here included in it and some initially called Ecphora are here excluded from it. Rapana tampaensis Dall (1890 [ 1890-1903]: 1 53; 1915:78, pl. 13: fig. 8), first referred to Ecphora by Coss- mann (1903:65), is from the Tampa Formation of Florida. The species also occurs in the "Silverdale" beds (USGS 23108) of North Carolina. These beds are approximately of the .same age. Current research in micro- and macro- paleontology of the Silverdale fauna indicates that it may be late Oligocene in age rather than early Miocene. The fragmentary specimen from these beds identified by Rich- ards (1943:524, pl. 85: fig. 16) as E. quadricostata, is appar- ently the same as an undescribed species from Silverdale in the U.S. National Museum collection (USGS 21943). The specimen (USNM 112520) from Church Hill, Mary- land (Calvert Formation) figured by Dall (1892 [1890- 1903] pl. 20: fig. 14) as Rapana tampaensis Dall, var.? and referred to as Ecphora tampaensis by Martin (1904:211, pl. 52: fig. 9) followed by Grabau and Shimer (1909:787, fig. 1152a) was later named Rapana ecclesiastica by Dall (1915:78). Martin had noted that "Fasciolaria (Lyrosoma) sulcosa" of Whitfield (1894, pl. 17: figs. 9, 10; not Conrad (1830:220, pl. 9: fig. 8) was related; subsequently Richards and Harbison (1942:211) synonymized Whitfield's species with ecclesiastica. I am indebted to the late W.P. Woodring for pointing out (pers. com.) that ecclesiastica should be referred to the genus Tritonopsis Conrad (1865:20) found in the late Eocene of Panama (Woodring, 1973:477, pl. 70: figs. 26, 27) and the Oligocene of Mississippi. Sohl (1964:173) has outlined the problem of considering Ecphora proquadricostata Wade, a Cretaceous species, as the earliest known Ecphora. Zalman Altschuler (pers. com.) has determined that the entire shell of E. proquadricostata is aragonitic. This fact strengthens my opinion that there is no direct genetic connection with the known later species, though as pointed out by Sohl, the Cretaceous species is morphologically like Ecphora. I believe that the earliest undoubted ecphoras are in the Oligocene both in Europe and in North America. Ecphora koeneni Gorges (1952:6, pl. 2: fig. 1 la, b) judging from the figure, is an Ecphora, sensu stricto. It is from the Oligocene of North Germany. The poorly preserved impression identified by Dall (1894:301) as "Ecphora quadricostata" from the "land phosphate" rock of South Carolina, is undoubtedly ofthe genus Ecphora. An examination of the associated specimens and Dall's list of species indicates that they come from the Oligocene Cooper Marl. Ecphora (Ecphora) gardnerae, new sp»ecies FlGURF IA,B Ecphora quadricostata. — Martin 1904:207, pl. 52: fig. 1. It is now known that most if not all of the fossils described by Say in 1824 came from Virginia rather than Maryland, contrary to Say's title "An Account of Some of the Fossil Shells of Maryland." According to Gardner (1948:201), "Mansfield believed from internal evidence that they came not from Maryland but from Virginia'' and Dall (1892 [1890-1903]:351) had earlier doubted the provenience of a Say species. Ward and Blackwelder (1975:9, 16) have shown that the common pecten ofthe Maryland Miocene is not Pecten madisonius Say as formerly universally used, but that the name in fact belongs to a Yorktown species of NUMBER 61 23 FIGURE 1.—Ecphora (Ecphora) gardnerae, new species, holotype, USNM 647519, height about 120 mm; A, apertural view; B, dorsal view. Virginia. This confusion of locality undoubtedly initiated the chain of coincidence that resulted in the common Ec- phora ofthe St. Marys Miocene of Maryland masquerading under the name "Ecphora quadricostata,' which properly belongs to the Yorktown species of Virginia. This St. Marys Miocene species is here named Ecphora (Ecphora) gardnerae, new species. In Ecphora gardnerae the four prominent spiral j-ibs become stronger with maturity, in contrast to the ribs in E. quadricostata, which become weaker with age. The holotype of Ecphora gardnerae (USNM 647519) is the spec- imen figured by Martin. Probably because the name Ecphora quadricostata had been preempted for the Maryland St. Marys species, the name Ecphora umbilicata (Wagner) has had some usage as the name for the Yorktown species. "Fusus umbilicata Wag- ner" Dall (1898 [1897]:9, pl. 2: fig. 2) is a synonym of Ecphora quadricostata Say, as very early recognized by Coss- mann (1898:110), as well as a homonym of Fusus umbilicata Smith (1839:98, pl. 1: fig. 2). It has also been used by Marfin (1904:209, pl. 52: fig. 4) for a Choptank Miocene species of Maryland, which apparently needs a name. Mans- field (1930:71) recognized that the Choptank species was not the same as F. umbilicata Wagner (i.e., E. quadricostata). Dall (1898:8) related the circumstances concerning "Wag- ner's plates" and reference to them in Bronn's Index (1848:517, 1849:455). Brochon's repeated reference (1849:119, 124, 127) to "Fusus quadricostatus Wagner" (with no mention of Say) establishes their circulation, but their subsequent treatment by Martin (1904:209) and by Mansfield (1930:70) as validly published is not justified. In any case, a date earlier than 1839 would have to be proved because of the prior use of the name by Smith. These bits of information indicate probable correspondence between Brochon and Wagner and perhaps realization by Wagner that his figure represented Say s species quadricostatus. Bro- chon (1849:128) does establish that "le Fusus de Wagner provient des couches pliocenes de Virginie," a fact appar- ently not known to Dall. Another nominal species, Ecphora parvicostata Pilsbry (1911:438, fig. 1), with only "Maryland" for locality, is apparently nothing more than an extreme variation of E. quadricostata and must have come from Virginia. A large well-preserved specimen (USNM 106919) of Ecphora in the National Museum of Natural History sup- posedly from Florida was identified by Dall as Ecphora quadricostata. Because it was repeatedly mentioned by Dall and undoubtedly had an early influence on his thinking concerning the age of the beds from which it was supposed to have come, it seems desirable to document and dispose ofthe specimen. It had come to the National Museum from R.E.C. Stearns, who was on an expedition to Florida in 1869. Dall (1885:82) first reported the specimen as found at Tampa "on the long rocky point"; later he (1887:166) identified the locality as Ballast Point, and later still (1890:8, 125) as "Long Key . . containing no solid rock of any sort.'' At this time Dall seems to have had some reservations probably due to the discrepancies. Although he still consid- ered the specimen as possibly from the silex bed, he recog- nized that the specimen was not silicified. Dall and Harris (1892:125) referred it to a "later horizon" and Dall's final notice (1903 [1890-1903]: 1596) in his "List of Species of the Floridian Miocene" repeated this pronouncement. A critical examination of the specimen and comparison with specimens from the St. Marys River leads to the conclusion that it is a specimen of Ecphora gardnerae from the St. Marys Miocene of Maryland. Stearns (1869:466-467) did not 24 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY mention the find in his account of his stay on Long Key or any other locality. His wide interests and knowledge of mollusks is so well demonstrated that it seems unlikely that a find so unusual would have gone unrecorded. There seems to be no satisfactory accounting for this confusion. Eppert's reference (1966:49, 58) to "Ecphora quadricostata umbilicata" is a lapsus and undoubtedly concerns Stearns' specimen. Ecphora (Ecphora) pamlico, new species PLATE 1: FIGURES 1, 2 Shells moderately large with angle-sided whorls; three prominent spiral thin flange-like costae at the whorl angles. Secondary sculpture of many spiral bands between costae; bands becoming obsolete or nearly so on the flattened shoulder; posterior interspace between the costae wider than anterior interspace. Aperture ovate; anteriorly pro- duced into a very narrow, broadly curved canal. Umbilicus large, rounded and bordered by a regularly and weakly stepped (or serrated) carina. Most specimens are both distorted and defective; neither spires nor canals are complete in any specimen. The holo- type is the only undistorted large specimen (Plate 1: figure 2). MEASUREMENTS.—Holotype, height about 65 mm, width about 65 mm; aperture of holotype not exposed; figured paratype, height about 58 mm, width about 44 mm. Ecphora (E.) pamlico is represented by 25 specimens; all are caught up in a phosphatized matrix with dark phosphate pebbles throughout. A small slab collected by Royal Mapes contains nine specimens. No specimen has been collected in place, but the associated matrix is considered by Gibson (pers. com.) to indicate beds lower than unit 5 ofthe Pungo River Formation. REMARKS.—Ecphora (E.) pamlico is related to a large undescribed species of Ecphora in the National Museum of Natural History from zone 10 ofthe Calvert Formation of Maryland, collected by the late Sydney F. and Doris Blake. It is also related to E. (E.) jauberti (Grateloup) (Plate 1: figures 3, 4) found in the Tortonian of Saubrigues, France. TYPES.—Holotype USNM 647668; figured paratype USNM 647671, unfigured paratypes USNM 647669- 647670, 647672-647679. OCCURRENCE.—Known only from the Pungo River For- mation at Lee Creek, North Carolina. Subgenus Stenomphalus Sandberger, 1861 Subgenus Stenomphalus Sandberger, 1861:222. The type-species by subsequent designation (Dall, 1890: 124) is Fusus cancellatus Thoma (= Ecphora (Stenomphalus) caerulea ornata Bucher). The nomenclatorial imperatives and the interspecific relationship are derived from the work of Zilch (1983:93-101, pl. 10), who has recently published the results of his studies of the species group to which the type-species belongs. Fusus cancellatus Thoma (1845:162, pl. 4: fig. 8) is four times preoccupied; first by Sowerby (1826:45). Braun's later, undescribed substitute name (1851:1131), listed thus "Fusus brevis A. Braun (F. cancel- latus Thomae a.o.a. O.S. 162)," valid only by the included reference to Thoma's species, is preoccupied by Fusus brevis Brown (1827, pl. 48: fig. 34). The earliest described species name in the group is Buccinum caeruleum Romer-Biichner (1827:18, pl. 1: figs. 1-3) published in a work so rare that it was not recorded in the famed Index Animalium of Sherborn. A copy of Romer-Biichner's work could not be located in the United States, and I have seen only a xerox ofthe pertinent part. A species named by Bucher (1913:93, 96, pl. 1: figs. 8-10) Stenomphalus cancellatus ornatus is from the type-locality of F. cancellatus. Since Wenz's (1932) res- urrection of Romer-Biichner's species name and revision of the nomenclature, S. caeruleus ornatus Bucher has been maintained as the valid name for the type-species of Sten- omphalus Sandberger. Presumably the species is quite vari- able; Thoma's type figures (1845, pl. 4: figs. 8a, 8b) show obvious differences from the somewhat larger specimens figured by Sandberger (1860, pl. 17: figs. 7, 7a, 7b). Sand- berger's figures have been considered as representing the typical form by Boettger (1883:218). Both Thoma and Sandberger reported the species as abundant at Hochheim, the type-locality. Thirteen specimens in the U.S. National Museum collections from three localities (Hochheim, Florsheim, and "Flonheim u. Alzey," including seven from the type-locality (Hochheim), are more nearly like Thoma's figures in size and outline, but some of them exhibit the broader spiral bands of Sandberger's figures. According to Zilch (1983) the type-locality is in the early Miocene "Ceri- thien-Schichten" ofthe Mainz Basin, Germany. The shells of the species of the subgenus Stenomphalus are characterized by a reduction in the strength ofthe spiral sculpture and a much less prominent umbilicus. The species are generally smaller than species of the typical subgenus. Ecphora (Stenomphalus) aurora, new species PLATE 2: FIGURES 1-5 fRapana (Ecphora) Moulinsii (Brochon).—Cossmann and Peyrot, 1924:534, pl. 14: fig. 47; pl. 15: fig. 19?. Shell moderately large for the subgenus, pyriform with rounded whorls bearing three primary low but prominent spiral bands, which in turn bear secondary bifid spiral bands; the anterior primary band hardly set off from the anterior secondary bifid spiral bands of the anterior of the body whorl; shoulder flattened and sunken below edge of poste- rior primary band. Broadly ovate aperture anteriorly pro- NUMBER 61 25 duced into a slightly curved siphonal canal. Umbilicus an- teriorly produced and bordered by a rudely stepped carina. All large well-preserved specimens of E. (S.) aurora are somewhat distorted; the strong step-like feature ofthe outer lip just below the shoulder on the figure of the holotype (Plate 2: figure 1) is a result of distortion. The umbilical region ofthe paratype (Plate 2: figure 5) is the least distorted of any specimen. MEASUREMENTS.—Holotype, height 80 mm, width 55 mm; illustrated paratype, height 44.5 mm, width 30.5 mm. SPECIMENS EXAMINED.—Ecphora (S.) aurora is repre- sented by 95 specimens including many fairly well-preserved specimens and some steinkerns. They all have a completely phosphatized matrix that Gibson (pers. com.) regards as occurring lower in the Pungo River Formation than the matrix associated with E. (E.) pamlico, new species. TYPES.—Holotype, USNM 647654 (Plate 2: figures 1- 3); illustrated paratype, USNM 647656 (Plate 2: figures 4, 5); other paratypes, USNM 647655, 647657-647667. OCCURRENCE.—Pungo River Formation, Lee Creek, North Carolina, and Saucats (Peloua), France. REMARKS.—Ecphora (S.) aurora is not related to any American species, but it seems to be the same as the species figured by Cossmann and Peyrot (1924) from France as Rapana (Ecphora) moulinsii (Brochon); particularly their figured specimen from the Burdigalian at Saucats (Peloua) (Plate 2: figure 7). Brochon's species (1849:117-128, figs. 1, 2) was described from the type Burdigalian at Leognan (Coquillat) and the original figures copied here (Plate 1: figures 5, 6) are strikingly different from the figures of Cossmann and Peyrot. Cossmann and Peyrot (1924:536) suggested that the specimen from the Helvetian at Salles figured by them may be reworked; if this is true, both species are confined to the Burdigalian. Stratigraphic Order of the American Species of Ecphora E. quadricostata (Say): Yorktown Formation and equiva- lents. Virginia to Florida; traditional late Miocene ofthe Coastal Plain; currently regarded as Pliocene by many micropaleontologists. E. gardnerae, new species: St. Marys Miocene of Maryland and Eastover Formation, late Miocene, of Virginia. (See Ward and Blackwelder, 1980:19, 28; pl. 1: fig. 2). "umbilicata'' of Martin: Choptank Miocene of Maryland. tricostata Martin: Choptank and Calvert Miocene of Maryland and upper part of Pungo River Formation (unit 7) in North Carolina. My report (see Espenshade and Spencer, 1963, table 10) of Ecphora cf. E. tricostata in a drill hole sample from central north Florida, said to be of middle(?) Miocene age, is based on fragmentary mate- rial. However, both the "cf." ofthe species and the query ofthe age should be removed. pamlico, new species: Pungo River Formation of North Carolina, but apparently below the occurrence of E. tricostata. aurora, new species: Lower part of the Pungo River Formation of North Carolina. tampaensis (Dall): Tampa Limestone of Florida, "Silver- dale beds' of North Carolina (USGS 23108); early Mio- cene or late Oligocene. "quadricostata'" of Dall: Cooper Formation Oligocene of South Carolina. Literature Cited Boettger, O. 1883. Palaeontologische Mittheilungen: Die Arten der Gattungen Sten- omphalus Sbg. und Cypraea L. im Mainzer Becken. Offenbacher Vereins fur Naturkunde Bericht, 22/23:217-224, plate 1. Braun,A. 1851. Die fossile Fauna des Mainzer Beckens: Wirbellose Thiere. In F.A. Walchner, Handbuch der Geognosie . . ., second edition, pages 1112-1141. Brochon, E.H. 1849. Note sur une pyrule nouvelle de Leognan (P. de Des Moulins.— P. Moulinsii, Nob.).—Quelques mots sur le genre.—Descriptions et figure de I'espece. Actes de la Societe Linneenne de Bordeaux, 16:117-128, 2 figures. Bronn, H.G. 1848. Index Palaeontologicus, oder Uebersicht der bis jetzt bekannten fossilen Organismen .... Volume 1/2, 1382 pages. 1849. Index Palaeontologicus, oder Uebersicht der bis jetzt bekannten fossilen Organismen .... Volume 3, 1106 pages. Stuttgart. Brown, Thomas 1827. [Illustrations ofthe Conchology of Great Britain and Ireland.] pages i-v, 52 plates [with extensive explanations]. London. Bucher, W. 1913. Beitrag zur geologischen und palaontologischen Kenntnis des jijngen Tertiars der Rheinpfalz. Geognostiche Jahresheft 26: 1- 103, plates 1-2. Conrad, T.A. 1830. On the Geology and Organic Remains of a part ofthe Peninsula of Maryland; with appendix. Journal of the Academy of Natural Sciences of Philadelphia, 6:205-230, plates 9, 10. 1843. Descriptions of a New Genus, and of Twenty-nine New Miocene, and One Eocene Fossil Shells ofthe United States. Proceedings of the Academy of Natural Sciences of Philadelphia, 1:305-311. 1865. Catalogue ofthe Eocene and Oligocene Testacea ofthe United States. American Journal of Conchology, l(l):l-35. Cossmann, A.E.M. 1898. [Review of] Notes on the Paleontological Publications of Profes- sor William Wagner, by W. H. Dall. Revue Critique de Paleozool- ogie,2e Ann.—1898, 3:110-111. 1903. Essais de Paleoconchologie Comparee. Volume 5, 215 pages, 9 plates. Paris: private publication. 1925. Essais de Paleoconchologie Comparee. Volume 13, 345 pages, 11 plates. Paris: private publication. 26 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Cossmann, A.E.M. and A. Peyrot 1924. Conchologie Neogenique de VAquitaine. 4(2):323-621, plates 8-18. Dall, W.H. 1885. Miocene Deposits in Florida. Science, 6:82. 1887. Notes on the Geology of Florida. American Journal of Science, (3)34(201):161-170. 1890-1903. Contributions to the Tertiary Fauna of Florida with Es- pecial Reference to the Miocene Silex-beds of Tampa and the Pliocene Beds of the Caloosahatchie River. Transactions of the Wagner Free Institute of Science of Philadelphia, 3, part 1 (1890):1- 200, plates 1-12; part 2 (1892):201-474, plates 13-22; part 3 (1895):475-570; part 4 (1898):571-948, plates 23-35; part 5 (1900):949-1218, plates 36-47; part 6 (1903):1219-1654, plates 48-57. 1894. Notes on the Miocene and Pliocene of Gay Head, Martha's Vineyard, Mass., and on the "Land Phosphate" of the Ashley River District, South Carolina. American Journal of Science, (3)48(286):296-301. 1898. Notes on the Paleontological Publications of Professor William Wagner. Transactions of the Wagner Free Institute of Science of Philadelphia, 5 [15 Oct. 1897]:7-11, 3 plates. 1915. A Monograph of the Molluscan Fauna of the Orlhaulax pugnax zone of the Oligocene of Tampa, Florida. United States National Museum Bulletin, 90:1-173, plates 1-26. Dall, W.H., and G.D. Harris 1892. Correlation Papers, Neocene. United States Geological Survey Bul- letin, 84:1-349, figures 1-43, plates 1-3. Engelmann, Wilhelm 1846. Bibliotheca Historico-Naturalis: Verzeichniss der Biicher Uber Natur- geschichte welche ... in den Jahren 1700-1846 .... Volume I, 786 pages. Leipzig. Eppert, H.C, Jr. 1966. Stratigraphy ofthe Upper Miocene Deposits in Sarasota County, Florida. Tulane Studies in Geology, 4(2):49-61, figures 1, 2. Espenshade, G.H., and C.W. Spencer 1963. Geology of Phosphate Deposits of Northern Peninsular Florida. United States Geological Survey Bulletin, 1 1 18:1-1 15, plates 1-12, tables 1-25. Ciardner, J.A. 1948. Mollusca from the Miocene and Lower Pliocene of Virginia and North Carolina, Part 2: Scaphopoda and Gastropoda. United States Geological Suriiey Professional Paper, 199-B: 179-310, plates 24-38. Gibson, T.G. 1967. Stratigraphy and Paleoenvironment ofthe Phosphatic Miocene Strata of North Carolina. Geological Society of America Bulletin, 78(5):631-650, 4 figures. 2 plates. Gorges, J. 1952. Neue Invertebrata aus dem Norddeutschen Oberoligozan. Pa- ldontologische Zeitschrift, 26(1/2): 1-9, plates 1-2. Grabau, A.W.A., and H.W. Shimer 1909. North American Index Fossils: Invertebrates. Volume 1, viii 4- 853 pages, illustrated. New York. Grateloup, J.P.S. de 1840. Conchyliologie fossile des terrains tertiaires du bassin de L'Adour Atlas, XX -H 12 pages, 48 plates. Bordeaux. Harris, G.D. 1937. First C;entury of Progress in Cenozoic Marine Invertebrate Pa- leontology. Geological Society of America Bulletin, 48(4):443-462. Huddesford, William, editor 1770. M. Lister, Historiae sive Synopsis methodicae Conchyliorum .... Altered edition in 6 parts: iv -I- 6 (notes) -1- 7 (plate explanations) 4- [ii| -t- 12 -(- 77 (index) pages, 1059 plates. Oxonii. Lister, M. 1685-1697. M. Lister, Historiae sive Synopsis methodicae Conchyliorum First edition (1685-1692), 1057 plates; second edition (1692-1697), 1059 plates. Londini. Mansfield, W.C. 1930. Miocene Gastropods and Scaphopods of the Choctawhatchee Formation of Florida. Florida Geological Survey Bulletin, 3:1-190, plates 1-21. Martin, G.C. 1904. Systematic Paleontology: Gastropoda. Maryland Geological Sur- vey, Miocene, pages 131-270, plates 39(part)-63. Pilsbry, H.A. 1911. A New Ecphora of the Chesapeake Miocene. Proceedings of the Academy of Natural Sciences of Philadelphia, 63:438-439, figure 1. Raup, DM. 1961. The Geometry of Coiling in Gastropods: Proceedings of the Na- tional Academy of Sciences, 47(4):602-609, 4 figures. Richards, H.G. 1943. Additions to the Trent Marl of North Carolina, yourna/ of Pa- leontology, 17(5):5I8-526, plates 84-86. Richards, H.G., and A. Harbison 1942. Miocene Invertebrate Fauna of New Jersey. Proceedings ofthe Academy of Natural Sciences of Philadelphia, 94:167-250, figures 1-9. plates 7-22. Romer-Biichner, B.J. 1827. Verzeichniss der Steine und Thiere, welche in dem Gebiete der freien Stadt Frankfurt und deren ndchsten Umgebung gefunden werden. Frankfurt am Main. [Not seen.] Sandberger, C.L.F. von 1858-1863. Die Conchylien des Mainzer Tertiarbeckens. 1-72, plates 1- 10, 1858; 73-112, plates 11-15, 1859; 113-152, plates 16-20, 1860; 153-232, plates 21-30, 1861; 233-272, plates 31-35, 1862; 273-358 + 8 unnumbered index pages, 1863. Wiesbaden. [Bibliographic details from p. 150 of F. Schondorf, 1907. Ver- zeichnis der im Naturhistorischen Museum zu Wiesbaden Auf- bewahrten Originale. Abteilung fiir Geologie und Palaontologie. 1. Originale zu Frid. .Sandberger, Die Konchylien des Mainzer Tertiarbeckens. Jahrbuch Nassauischen Vereins Naturkunde, 60:148-169.] Say, T. 1824. An Account of Some of the Fossil Shells of Maryland.yourna/ of the Academy of Natural Sciences of Philadelphia, 4:124-155, 410, plates 7-13. (Reprinted 1896 in G.D. Harris, A Reprint ofthe Paleontological Writings of Thomas Say, Bulletins of American Paleontology, I (5):300-346.] Shattuck, G.B. 1904. (ieological and Paleontological Relations, with a Review of Ear- lier Investigations. Maryland Geological Survey, Miocene, pages xxxiii-cxxxvii. Smith, j. 1 839. On the Last Changes in the Relative Levels of the Land and Sea in the British Islands. Wernerian Natural History Society Memoir, 8:49-1 13, plates 1-2. .Sohl, N.F. 1964. Neogastropoda, Opisthobranchia and Basommatophora from the Ripley, Owl Creek, and Prairie Bluff Formations. United States Geological Survey Profe.i.sional Paper, 331-B: 1-344, plates 1-52. .Sowerby, j. 1812-1846. The Mineral Conchology of Great Britain .... 7 volumes. London. (For bibliographic details and dates see p. 323 of R.B. Newton, 1 891. Systematic List ofthe Frederick E. Edwards Collection of British Oligocene and Eocene Mollusca in the British Museum NUMBER 61 27 (Natural History) xxviii -»- 365 pages, 1 table. London: British Museum (Natural History).] Steams, R.E.C. 1869. Rambles in Florida. American Naturalist, 3(6):281-288; (7)349- 356; (8):397-405; (9):455-470. Thoma, C. 1845. Fossile Conchylien aus den Tertiarschichten bei Hochheim und Wiesbaden Gesammelt, und in Naturhistorischen Museum zu Wiesbaden AufgesteUt. Jahrbuch Nassauischen Verein fiir Natur- kunde, 2:125-166, 4 pUtcs. Vokes, H.E. 1957. Miocene Fossils of Maryland. Maryland Geological Survey Bulletin, 20:1-85, plates 1-31. Ward, L.W., and B.W. Blackwelder 1975. ChesapecUn, a New Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. United States Geological Survey Professional Paper, 861:1-24, figures 1- 2, plates 1-7. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene Beds of the Chesapeake Group, Middle Atlantic Coastal Plain. UniUd States Geological Survey Bulletin, 1482-D: 61 pages, 25 figures, 5 plates. Wenz, W. 1932. Wirbellose Metazoa des Neozoikums. In W. Salomon-Calvi, Oberrheinischer Fossilkatalog, 7:1-95. Whitfield, R.P. 1894. Mollusca and Crustacea of the Miocene Formations of New Jersey. United States Geological Survey Monograph, 24:1-193, plates 1-24. Wilkins, G.L. 1957. Notes on the Historia Conchyliorum oi MdiVtm Lister (1638-1712). fournal of the Society for the Bibliography of Natural History, 3(4): 196-205. Woodring, W.P. 1973. Geology and Paleontology of Canal Zone and Adjoining Parts of Panama: Description of Tertiary Mollusks (Additions to Gastro- pods, Scaphopods, Pelecypods: Nuculidae to Malleidae). United States Geological Survey Professional Paper, 306-E:453-540, plates 67-82. Zilch, Adolf 1983. Die Typen und Typoide des Natur-Museums Senckenberg, 69: Mollusca: Muricidae: Rapaninae: Stenomphalus. Archiv fur Mol- luskenkunde, I I3(I/6):93-101, plate 10. 28 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PI A I I I I, 2 Ftfihiira (F(phiira) firimlno. new spci ics: I, |).ii .il \ |)c, I SNM (>47()71, .ipci tin .il \ lew , luiglil .iboiil .^>H mill. L', liol(.l\|.<-, ( ,S\\1 (.17(p(.K, (I..IS.1I \i< u. Iici^lil .ilx.iil 65 mm. '.'<. \. F.tpliora {/■(phiira) jtiiihirli ((.i.il(l<)U|)), ,S.inl)iij.;u(s. Ii.iii(<-, I oi lorn.111 Mi(i( mm: I, .i|){iimal view: 2, dors.il \ii\\; !^. apu.il \ie\\; 4, apertural view; .">, dorsal view. 6, 7. fRapana (Ecphora) moulinsu st-nsii Cossmann .iiid PcMot: (i, .S.illes, Kiaiui-, 1 k-l\ \ SOUTH /5^ V CAROHNA [/ \ GEORGIA FLORIDA 150 miles Scale: FIGURE 1.—Location of major localities and formational units discussed in text: 1 = Kirkwood Formation in vicinity of Salem and Jericho, New Jersey; 2 = Calvert, Choptank, and St. Marys formations at Calvert Cliffs, Mary- land; 3 = Yorktown Formation along Chowan River, North Carolina, 4 = Lee Creek Mine, North Carolina; 5 = Waccamaw Formation in southern North Carolina and northern South Carolina; 6 = Torreya, Chipola, Oak Grove, and Jackson Bluff formations in northwestern Florida; 7 = Caloos- ahatchee Formation in southern Florida. River Formation has phosphatic sands composed of primary grains of phos[3hate (oval in shape, light to medium brown in color generally) in the lower and middle parts, with some dolomitic and diatomaceous layers; upwards the phosphatic sands begin to interbed with limy layers, causing the result- ing limestones to contain abundant phosphate grains; the uppermost beds consist of limestones having abundant molds of mollusks and few phosphatic grains giving way upward to loosely consolidated bioclastic debris, which does not contain any appreciable amount of phosphatic material. 34 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY LiJ Z UJ o o b- w UJ OH : 3.35 Buff to yellow cross-bedded medium sand mMm ^^S^*^*^^'^'^> 1.64 3.65 1.22 0.91 Blue silty and clayey sand, abundant shells (Unit 9) Blue to greenish blue slightly silty medium to coarse sand, abundant shells and corals (Unit 3) Blue sand with 0.5m boulders of well-indurated quartz sandstone, abundant shells (Unit 7) Blue silty sand, abundant shells (Unit 6) o 1—) 7.01 Blue silty and clayey fine sand, scattered calcitic shells and barnacles, lenses of rotten Turritella (Unit 5) O fa O O < a: o Li. a: UJ > 5 o o z Z! 3 O 0 0_Q_0 O Oc - J Q e. o^r» I o^ o © o«^-.o O O Q. Q 0 O G '.V. ^^o!i LG o o oVo o o a a_D o o o c> o o 0 ^0 o Ji^o o^,A.o ■^-1 o oTj o e p o ^ o Q_0 o (aero « o g^r^o o_Q o © o ooo© o o^^ 3 Q_0 O O 0 O ~ €F0 0 O O^l > Q O^g^O 0 ^O 0 Q'Q 0 o BO g e 0 O Tj o o ©o Q_a_o Wl O 0 0 O O O O 0 e Q" Q o WT^cnif 'eV'o%%°oV'e' 1.83 0.61 3.05 0 30 1 07 0 76 0 .91 0 .91 1 52 0 .91 7.14 Blue silty and clayey fine sand, abundant rotten Turritella, common pectens (Unit 4) Blue silty fine sand, common pectens (Unit 3) Blue silty and clayey fine sand, abundant echinoid spines, scattered shells and barnacles, phosphate and quartz pebbles in lower 1 m (Unit 2) Blue silty sand, large phosphate pebbles ar d bone, shells (Unit 1) Yellow-green silty and clayey sand, abundant bryozoan fragments (Unit 7) Yellow-green sand, hydrozoan fragments interbedded with dark phosphatic lenses Gray phosphatic sandy limestone, molluscan molds and casts (Unit 5) lUnit b) Interbedded gray phosphatic limestone and dark brown phosphatic sands (Unit 4) Dark greenish brown silty medium grained phosphatic sands (Unit 3) Greenish gray indurated diatomaceous clay (Unit 2) Dark greenish brown medium to fine phosphatic sand (Unit 1) FIGURE 2.—Section of Miocene and younger strata exposed in the northwest wall of the test pit, Lee Creek Mine. The lower units of the Yorktown Formation are bluish clays and .sands containing large amounts of secondary phosphatic material (irregularly shaped, black in color), which rapidly decreases in size above the base; overlying this is a sequence with abundant echinoid spines in a fine quartz sandy matrix, the abundance of spines sometimes giving a fibrous appearance; the next sequence upward has large numbers of Turritella, which generally have been diagenelically altered to a chalky and partially dissolved appearance, and near the top the beds are partially indu- rated because of the local redeposition of the carbonate from the shells. With the beginning of mining operations several years later, va.st amounts of the Pungo River and Yorktown formations were exposed in the spoil piles derived from the dry stripping operations. Becau.se of the large size of the NUMBER 61 35 drag-line bucket (72 cubic yards; 55 cubic meters) and the careful stripping of the layers, material from the same stratigraphic intervals tends to be localized on the spoil piles. The localized material can be placed within the strat- igraphic sequence by comparison of the lithologies and faunas with the known distribution in the outcrop sequence in the walls ofthe test pit, and thus into the distinctive unit sequence of Gibson (1967). Although some ofthe measured and illustrated specimens were collected in place from the walls ofthe test pit or large mining pit, most specimens are from the spoil piles; the great amount of areal exposure of the units uncovered many well-preserved specimens from a relatively narrow and known stratigraphic interval. CORRELATION Most of the species identified to date from exposures of the Pungo River Formation in the Lee Creek Mine also are found in the Calvert Formation of Maryland and Virginia. Three species, Chesapecten coccymelus, Ostrea percrassa, and Ecphora tricostata are restricted elsewhere to the Calvert Formation in Maryland and Virginia and the coeval Kirk- wood Formation in New Jersey. Chesapecten nefrens from the uppermost part of the Pungo River Formation in the mine is restricted to the upper part ofthe Calvert Formation and the Choptak^ Formation in Maryland and northern Virginia. The other species of mollusks reported to date from the Pungo River Formation include Pecten mclellani, new species, and two new species of Ecphora: E. pamlico (p. 24) and E. aurora (p. 24), which in North America are restricted to the Lee Creek exposure of the Pungo River Formation. The three species restricted to the Calvert Formation and the one species that ranges from the Calvert into the Choptank Formation permit correlation ofthe Pungo River Formation in North Carolina with the Calvert Formation in Maryland. The similarity ofthe span of time represented in the two formations is unknown at present, but evidence to date from the pectens suggests that they have a similar time span. The Calvert Formation in Maryland consists of 16 beds (zones 1-16 of Shattuck, 1904). Pecten humphreysii is known from beds 1-10, the lower and middle part ofthe Calvert. Chesapecten nefrens occurs in bed 14 and ranges upward into the Choptank Formation. The specimens from the Lee Creek Mine are from the uppermost beds of the Pungo River Formation. Thus the superposition ofthe two species in the Pungo River Formation at the Lee Creek Mine is the same as in the Calvert, with an indicator of bed 10 or older strata (Pecten hymphreysii) being overlain by an indicator of bed 14 or younger (Chesapecten nefrens). The considerable thickness of strata below the occurrences of Pecten humphreysii in the upper middle part of the Pungo River Formation may correspond to the time represented by the strata below bed 10 of the Calvert Formation in Maryland. The types of lithologies are different, phosphatic sands in the Pungo River Formation and clayey sands and diatomaceous clays in the Calvert Formation, but a similar time span for the two formations rather than just a slight overlap of part of one formation with a part of the other is indicated. Gibson (1983a:38, 63; 1983b:359) has found younger parts of the Pungo River Formation to the north and east of the section in the mine, and these strata appear to be younger in age than any part ofthe Calvert Formation so far dated. The age significance of the planktonic Foraminifera of the Pungo River Formation was discussed by Gibson (1967; 1983b). The assemblages from the Pungo River Formation on which ages were obtained occur in the upper part ofthe formation. These assemblages are referable to zones N8 or possibly early N9 in the Neogene planktonic scale (Blow, 1969:229, 230), which is presently accepted as approximat- ing the early to middle Miocene transition (Blow, 1969:203, 265ff; Berggren and Van Couvering, 1974:202, 27Iff). The foraminiferal assemblages in the lower and middle parts of the formation are too poorly preserved to be identifiable. A similar assemblage referable to zone N8 or N9 also is found in bed 10 of the Calvert Formation in Maryland (see Gibson 1983b:360), and thus these two parts ofthe two formations have a similar age, approximating the early to middle Miocene boundary. The time ranges of Chesapecten coccymelus and C. nefrens thus seem to be similar in the different geographic areas. Pecten humphreysii also appears to have a similar range in North Carolina, Virginia, Maryland, and New Jersey, oc- curring in what are considered to be generally time-equiv- alent strata (Gibson, 1967:636; 1983a:38). Banks and Hunter (1973) reported this species from the Torreya For- mation in Florida, and some of their specimens are illus- trated in the present paper (Plate 4: figures 4-6). (The Torreya Formation of Banks and Hunter (1973) is herein adopted for U.S. Geological Survey usage.) The strata in which they occur, however, are tentatively assigned by them to the planktonic foraminiferal zones N5 and N6, consid- erably older than the present ages known for the strata bearing P. humphreysii in the Lee Creek Mine and north- ward (N8 and N9). The age ofthe Torreya Formation may be refined upward, but if not, it will mark a significantly older occurrence of P. humphreysii in Florida than presently known in the North Carolina-Maryland area. Another pos- sibility is that the lower part ofthe Calvert and Pungo River formations, which are not dated by planktonic Foraminifera because of lack of specimens and/or poor preservation, could be of an age older than N8, thus similar to the Torreya. The upper part of the Yorktown Formation in Virginia and North Carolina has been correlated with the Duplin Formation of the southern part of North Carolina and adjacent Georgia (Mansfield, 1944, table 1). The Ecphora 36 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY and Cancellaria zones of the Choctawhatchee Formation in Florida were correlated with the Yorktown Formation by Mansfield (1944, table 1). The Choctawhatchee Formation has been reinstated, redefined, and stratigraphically re- stricted to include only the lower part of former usage by the U.S. Geological Survey; its upper part, the Ecphora and Cancellaria zones, is now placed in the Jackson Bluff For- mation of Puri and Vernon (1964). A number of pectens restricted to the Yorktown Formation in Virginia and North Carolina are also found in the Jackson Bluff Formation. They include Chesapecten jeffersonius, Argopecten eboreus loat- sonensis, and A. comparilis. These species support the cor- relation of these formations. Mansfield (1936, 1944) divided the Yorktown Formation in Virginia and North Carolina into two zones. Zone 1 or the Pecten clintonius zone is overlain by zone 2 or the Turritella alticostata zone, which is composed of three sets of beds. Units 1 and probably all of 2 of the Yorktown Formation in the Lee Creek Mine of Gibson (1967; see also Figure 2) belong to Mansfield's zone 1, and the overlying units 3 to 5 belong to zone 2. Planktonic Foraminifera from zone 1 ofthe Yorktown in the northern part of North Carolina and in the Lee Creek Mine are of an early Pliocene age, planktonic zone N19/ N20 (Gibson, 1983b:363). Mansfield's zone 2 belongs to younger parts of zone N19/N20 and probably extends into zone N21 (late Pliocene). The upper part ofthe fossiiiferous strata in the Lee Creek Mine, termed the upper shell bed (units 8 and 9 of Gibson, 1967) was included in the Yorktown Formation by Gibson (1967) because it appeared to be the youngest part of the depositional cycle of later Cenozoic strata in eastern North Carolina. Other strata of a similar age are found at Mt. Gould Landing along the Chowan River in northeastern North Carolina (Figure 1), and these were also placed in the upper part of the Yorktown Formation by Mansfield (1944) (although given a younger age than the classic York- town by Hazel, 1971). The upper shell bed (units 8 and 9) and the underlying boulder bed and fossiiiferous bed (units 6 and 7 of Gibson, see Figure 2) appear to be part of a sequence that is .separated from the rest of the Yorktown by an unconformity. The age of these strata is younger than that ofthe typical Yorktown beds in most of North Carolina. These units are probably time-equivalents of the Croatan Formation, the type area of which is slightly south of the Lee Creek Mine, and the Waccamaw Formation, which is exposed in southern North Carolina and northern South Carolina (Figure I). As the lithology is similar to that ofthe Croatan Formation, which is probably in the same deposi- tional basin (Gibson, 1983a:74; 1983b:364), the upper part ofthe fo.ssiliferous strata in the mine, units 6-9, is assigned to the Croatan Formation. The James City Formation of DuBar and Solliday (1963) is considered to be synonymous with the Croatan Formafion (Hazel, 1983:84-85). The upper part of the Croatan Formation is correlated with the Waccamaw Formation, and both formations are considered time-equivalents of the Caloosahatchee Forma- tion in Florida. There are seven species of pectens in com- mon between the Waccamaw and Caloosahatchee forma- tions: Pecten brouweri, P. raveneli, Argopecten eboreus, A. vicenarius, Stralopecten ernestsmithi, Leptopecten leonensis, and Amusium mortoni. Two of these species are restricted to the Waccamaw and Caloosahatchee formations, Stralopecten er- nestsmithi and Pecten brouweri, and support the correlation of the two units. The planktonic Foraminifera support a correlation with the early Pleistocene zone N22 for part, at least, of the Waccamaw and Croatan formations, with a probable late Pliocene age or zone N21 for the remainder (see Gibson, 1983b:364). BIOSTRATIGRAPHY OF THE PECTINIDAE The pectens, as already noted, are ideal guide fossils to the upper Cenozoic deposits of the Atlantic Coastal Plain. Species range zones often coincide with formational bound- aries, which is not surprising as the formations characteris- tically used in the Atlantic Coastal Plain are in most in- stances biostratigraphic rather than lithostratigraphic units. Thus, the pectens are one of the most prominent markers of the biostratigraphic "formations.' In addition, changes in the assemblage, either at the specific or subspecific level, sometimes allow further biostratigraphic subdivision within a formation. The following sequence of pectens may be used to sub- divide the strata of the Chesapeake group, starting from the ba.sal unit, the Calvert Formation (Figure 3). Pecten humphreysii and Chesapecten coccymelus are re- stricted to the lower and middle part of the Calvert For- mation in Maryland, occurring from bed 1 to bed 10, and to the Pungo River Formation in North Carolina. The upper part of the Calvert Formation and the overlying (Choptank Formation are characterized by the occurrence of Chesapecten nefrens, which also occtirs in the uppermost part ofthe Pungo River Formation in North Carolina. The Si. Marys Formation in Maryland is characterized by Ches- apecten santamaria, with a change in the species morphology upward through the beds. Strata ofthe Maryland St. Marys and Choptank formations are not known south of northern Virginia (Gibson, 1970). The St. Marys Formation in Vir- ginia (considered the basal part ofthe Yorktown Formation, Gibson, 1971) is marked by the occurrence of Chesapecten middlesexensis throughout the formation, although with a series of morphologic variations, and in its upper part by Argopecten eboreus urbannaensis and Placopecten clintonius rappahannockensis. Both Chesapecten santamaria and C. mid- dlesexensis show considerable variation throughout their NUMBER 61 37 FIGURE 3.—Range chart of the common late Cenozoic pecten species occurring in the formations of the central Atlantic Coastal Plain. chronologic range, and further subdivision of the strata may be possible. The lower beds of the Yorktown belonging to zone 1 of Mansfield, are characterized by the occurrence of Placopec- ten clintonius clintonius along with the first appearance of Chesapecten jeffersonius jeffersonius. In the middle part ofthe Yorktown Formation, the lower part of Mansfield's zone 2, the Chesapecten stock changes to C. jeffersonius septenarius and C. madisonius. Other subspe- cies of Argopecten eboreus become diagnostic, such as A. eboreus watsonensis in the lower middle part, giving rise to A. eboreus eboreus in the middle part. Chlamys decemnaria is also an important index to this part ofthe section. The upper part of the Yorktown Formation is character- ized by some of the more advanced forms of Argopecten eboreus eboreus, A. eboreus bertiensis in a few localities along with A. eboreus aff. A. eboreus solarioides, advanced forms of Chesapecten madisonius, along with a very few advanced specimens of C. jeffersonius septenarius. The younger Croatan and Waccamaw formations contain new groups such as Pecten brouweri, Stralopecten ernestsmithi, Argopecten vicenarius, along with the abundant specimens of the various subdivisions of A. eboreus solarioides. Other species of pectens are found in the strata of the 38 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY s c I c <-> O ^ O I 6 J Q- I ^ ..Wnit.?. I UMZ Unit 6 ri FIGURE 4.—Distribution of species of pectens in the test pit strata ofthe Lee Creek Mine. Chesapeake group; however, they are either rare or their range is uncertain at the present time. Distribution of species in the Lee Creek Mine is given in Figure 4. PHYLOGENY OF THE PECTENS Although Dall (1898) and subsequent workers mentioned relationships among the various groups of pectens, Mans- field (1936) developed the first extensive phylogenies ofthe late Tertiary pectens ofthe Atlantic and Gulf Coastal plains. Modifications have been made in some ofthe lineages, but in large part Mansfield's phylogenies still are generally accepted. Wallers (1969) detailed phylogeny of the Argo- pecten gibbus stock, however, involved changes from that of Mansfield. In the present paper, the .species stocks and their inferred phylogenies are given, when possible, in the discussion of the individual species and also summarized in Figure 5. Phylogenies have been proposed, either in Mansfield (1936) or herein, for the (Chesapecten group, the Argopecten eboreus stock, the Placopecten group, and the probable Pecten mclel- lani lineage. Phylogenies have not been developed for (Chla- mys decemnaria and Amusium, the other two groups found in the Lee Creek Mine. Although phylogenies have been developed for late Ter- tiary pectens, little has been determined concerning the origin of the groups. The absence of information is due both to the lack of strata of immediately preceding age (upper Eocene, Oligocene, and lower Miocene strata are poorly represented in the central and northern Atlantic Coastal Plain) and also to the lack of knowledge of the faunas existing in older strata. The pectens found in strata of late Eocene and Oligocene age are quite different from those found in the lowermost Miocene deposits of the Calvert and Pungo River formations. The earliest recognized representatives ofthe Chesapecten stock appear in the Calvert Formation in Maryland and Virginia. If the ancestral forms were confined to the central and northern parts of the Atlantic Coastal Plain because of environmental restrictions, determining them will be diffi- cult because strata of Oligocene and early Miocene age crop out in only one place in this area. In North Carolina, Oligocene and possibly lower Miocene strata are present, but forms ancestral to the Miocene pectens have not been reported. It may be necessary to look to other areas, possibly Florida, to find the ancestral forms that later moved north- ward into this area. Therefore, at the present time, while phylogenies have been proposed for most groups, early Tertiary ancestral groups remain unrecognized. BIOGEOGRAPHY AND PALEOCLIMATE For many years, probably since Dall (1904), the environ- ment during deposition of the lower Miocene deposits of Florida (of Dall, now in part Pliocene) was considered to be very warm, followed by progressive cooling. After the early Miocene, cooling presumably would lead to the southward migration of the faunas found in the Chesapeake area, possibly resulting in a mixing ofthe more northern species with the indigenous Florida assemblages. A result of this faunal migration would be strong provincialism in the northern earlier Miocene faunas, such as those of the Cal- vert compared to those of the Chipola or Oak Grove for- mations of Florida in contrast to the more widespread distribution of the faunas in the later deposits considered Pliocene in this volume. The faunal provincialism between the Chipola (lower Miocene) and/or Oak Grove (middle Miocene) formations of Florida and the more northern Calvert Formation is well marked by the distribution ofthe mollusks in the two areas. The exact correlation of these units is uncertain at this time, becau.se some authors regard the Chipola as being slightly older than the (Calvert, and the Oak Grove Formation as l^eing more or le.ss equivalent to the Calvert (Mansfield, 1944). C^orrelations place the Hawthorn Formation in Flor- NUMBER 61 39 N •^ S icus CROATAN -<^ WACCAMAW sexensis 1 1 c 0 "o S n eboreus eborei CD 2 .E O — -Q a <" ■ -D c ■ "• i? B- i 8- ■ 0) o> ,A intonius ^^H off. P. magella "VIRGINIA ST. MARYS" lefre / sjef n [ef Che naen 3orei 0) t3 (U c < '^ o ^ us cl a. cten r rsoniu pecte urban ten el Argop >rgope □nnoc intoni anicus ST. MARYS esape Chesa oreus gopec <: appahi o c 0) agellc -C c ^ "o E U 9) (U < a> melus / aped (Cten toniu: lacop ecten >^ / c a- Q. o occ '' JC U 8- cli aco ■^ u < c a. CHOPTANK en humphrey Pecten mcle Chesapecten Placopecti ^^^.——" u .^ 0) a. 1 7 / 1 CALVERT -^^ PUNGO RIVER 1 1 ,^^ 1 V I ^ 1 FIGURE 5.—Phylogeny of some pecten species occurring in Miocene through lower Pleistocene strata in the Atlantic Coastal Plain. The placement of the boundary between zone 1 and zone 2 of the Yorktown Formation is uncertain, as is the relationship between Pecten humphreysii and P. mclellani. ida and southern Georgia as at least in part equivalent in age to the Calvert (Gibson, 1967), a correlation given some additional support by the newly noted occurrence in both formations of (Chlamys nematopleura Gardner (Druid Wilson, pers. comm., 1976). The Hawthorn appears to be at least in part ofthe same age as the Chipola (Gibson, 1967). A search ofthe literature and the USNM collections was made to determine correlation of the pecten assemblages between the various Neogene formations in Florida, North Carolina, and Maryland. The following six species of pectens have been reported from the Chipola Formation (Dall, 1898:720, 729, 733, 740, 755; Gardner, 1926:44, 46, 47, 50; Tucker-Rowland, 1936a:478, 1936b: 1007, 1938:11, 58): Pecten burnsii Dall, 1898, (Chlamys acanikos Gardner, 1926, C. alumensis (Dall, 1898), ""Chlamys" chipolana (Dall, 1898), Nodipecten condy- lomatus (Dall, 1898), and Amusium precursor Dall, 1898. Four species of pectens are reported from the Oak Grove Formation, including one species that also occurs in the Chipola Formation (Dall, 1898:775, 729; Gardner, 1926:45, 46, 49, 50; Tucker-Rowland, 1938:12, 13, 70): (Chesapecten sayanus (Dall, 1898), Nodipecten condylomatus (Dall, 1898), Pseudamusium diktuotum Gardner, 1926, and Pseudamusium sp. of Gardner, 1926. Five species of pectens are found in the Calvert Formation (Dall, 1898:720, 741, 753; Glenn, 1904:372, 373, 374; Schoonover, 1941:188, 201; Tucker-Rowland, 1936a:478, 1936b: 1007, 1938:68; Ward and Blackwelder, 1975:8, 9): Pecten humphreysii Conrad, 1842, Chlamys nematopleura (Gardner, 1936, (Chesapecten coccymelus (Dall, 1898), C. nef- rens Ward and Blackwelder, 1975, and Pseudamusium ceri- 71US (Conrad, 1869). The Pungo River Formation, from the only known out- crop in the Lee Creek Mine, also contains five species of pectens (Gibson, 1967:636, and this paper): Pecten mclellani, new .species, P. humphreysii Conrad, 1842, Chesapecten coc- 40 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY cymelus (Dall, 1898), (C. nefrens Ward and Blackwelder, 1975, and Amusium sp. There are no species in common between the Chipola or Oak Grove formations in Florida and the Pungo River Formation in North Carolina or the Calvert Formation in Virginia and Maryland. The complete difference in assem- blages supports the inference of a high degree of provin- cialism in Calvert-Chipola-Oak Grove time. The Chipola Formation is considered to be of very warm water origin with a number of tropical elements in the molluscan fauna. The Calvert Formation is of a cooler environment; just how much cooler is a matter of some controversy. Gibson (1962) considered the foraminiferal fauna of the Calvert Forma- tion to be of a temperate nature, probably similar to the conditions presently existing off the Maryland coast today. The basis for this conclusion was that, of the 41 species of Foraminifera found in the formation, 7 are living species characteristic of temperate waters, while none ofthe living species are of exclusively warm water distribution (restricted to areas south of Cape Hatteras). However, F.C. Whitmore (pers. com., 1974) considers the Calvert Formation to rep- resent a warm to possibly subtropical environment based upon the vertebrates, including crocodiles and otoliths. Whatever the climatic conditions may have been, there were considerable differences between Florida and the Chesapeake Bay area, which resulted in the provincialism of the pectens and other molluscan and foraminiferal groups. The difference between the pectens of the Calvert and Pungo River formations and those of the Chipola and Oak Grove formations in Florida indicates that the main provincial barrier was south of central North Carolina. This supports the similar conclusion of Gibson (1967), based upon the benthic and planktonic Foraminifera, that the main provincial boundary was to the south ofthe Lee Creek Mine. Later, in the Miocene and Pliocene (i.e., Yorktown), according to Dall (1904), a southward migration of the species from the Chesapeake area took place, leading to the presence of cooler water species in the Florida area. This hydroclimatic change would lead to a lesser amount of provincialism, and this change is refiected in the pecten a.ssem blages. Nine species of pectens from the Yorktown Formation have been reported in the literature or are in the USNM collections of the National Mu.seum of Natural History (Dall, 1898:722, 725, 730, 741, 749, 750, 757; Gardner, 1944:30, 31, 32, 34, 36, 37, 39; Man.sfield, 1936:178-180; Tucker-Rowland, 1936a:480, 1936b: 1008, 1009; 1938:15, 19, 33, 38, 40, 52, 59; Waller, 1969:52, 59; Ward and Blackwelder, 1975:13): Pecten smithi Olsson, 1914, (Chlamys decemnaria (Conrad, 1834), C rogersii (Conrad, 1834, Ar- gopecten eboreus (Conrad, 1833), A. comparilis (Tuomey and Holmes, lHb7), Placopecten clintonius (S'd'y, \H24), (Chesapec- ten jeffersonius (Say, 1824), Leptopecten sp., and Amusium worton? (Ravenel, 1844). The following seven species of pectens have been re- ported in the Ecphora and Cancellaria facies of the Jackson Bluff Formation of Florida; only these two facies are consid- ered coeval with the Yorktown Formation (Gardner, 1944:34, 36, 37, 39; Mansfield, 1932:56-65; Tucker-Row- land, 1936a:480, 481, 482, 1938:33, 40, 59; Waller, 1969:52, 59): Pecten ochlockoneensis Mansfield, 1932, Fla- bellipecten macdonaldi (Olsson, 1922), Argopecten eboreus (Conrad, 1833), A. comparilis (Tuomey and Holmes, 1857), (Chesapecten jeffersonius (Say, 1824), Leptopecten leonensis (Mansfield, 1932), and Amusium mortoni (Ravenel, 1844). Foin- of these species are found in both the Yorktown andJack.son Bluff formations. They 'dre Argopecten eboreus, A. comparilis, (Chesapecten jeffersonius, dnd Amusium mortoni. This is in marked contrast to the Calvert and Chipola formations of early and middle Miocene ages, during which time there were no species in connnon between the two areas. It is important to determine whether this overlap is the result of a southward migration of the Chesapeake area pectens into Florida, as postulated by Dall (1904), and thus a cooling trend, or a northward migration of species from Florida, indicating a warming trend through the Coastal Plain as postulated by Gibson (1967) and Hazel (1971). The geologic record is reasonably good between the Calvert to Yorktown ages in the Chesapeake area and the Chipola to Jackson Bluff ages in Florida. An examination ofthe origins of the four connnon species suggests that there was move- ment both ways. The earliest recognized members ofthe (Chesapecten stock are (C. coccymelus in the Calvert and Pungo River formations of late early to early middle Miocene age and C. sayanus in the Oak Grove F"ormation of early middle Miocene age (Huddlestun, 1976). Correlations would suggest that the northern occurrences are slightly older. Although C. jeffer- sonius is found both in the Chesapeake area and Florida, the development of C middlesexensis from which it came is mainly or solely in the Chesapeake area and would seem to indicate a southward migration of this species group into Florida. Although the early members of the Argopecten gibbus stock are characteristic of the Florida area, it appears that the earliest recognized member of the A. eboreus lineage within that stock, A. eboreus urbannaensis, is found in the (Chesapeake area (Waller, 1969). The later development of A. eboreus would indicate a southward movement of the stock and diversification into a number of forms. If A. eboreus urbannaensis belongs to a separate lineage from the other forms placed in A. eboreus, then the earliest member ofthe A. eboreus stock would be A. eboreus watsonensis, which appeared at approximately the same time both in Virginia and Florida from southern ancestry. Argopecten comparilis is a phyletic descendant of A. choc- tawhatcheensis (Mansfield) according to Waller (1969:27). The latter species is found only in Florida, and thus the NUMBER 61 41 immediately following A. comparilis, which is found at ap- proximately the same time in both Florida and Virginia- North Carolina, would have southern ancestry. Amusium mortoni presents a complex problem in terms of occurrences. Although specimens of A. mortoni have been reported from pre-Yorktown beds in the Chesapeake area (Dall, 1898:757; Gardner, 1944:39), Mansfield (1932:65) restricts the species to Yorktown-Jackson Bluff and younger strata, correctly crediting the older reported occurrences of misreading of localities (see discussion under Amusium sp.). Mansfield (1936:180) lists A. mortoni as occurring only in the younger part of the Yorktown, while occurring in the slightly older Ecphora zone of the Jackson Bluff For- mation. If this correlation is valid, A. mortoni first appeared in Florida and moved into the Chesapeake area later in Yorktown time. Huddlestun (1976), however, reported the Jackson Bluff to be of late Zanclian age; if so, this age would place it very close to the age of the Yorktown strata in which it occurs, indicating a similar time of origin in the two areas. Therefore, ofthe four groups, one, Chesapecten jefferson- ius, is a southward migrant; one, Argopecten eboreus, a prob- able southward migrant; one, A. comparilis, a probable northward migrant; and one, Amusium mortoni, a possible northward migrant. Thus, in the pectens, the similarity in the fauna is due to a two way movement between Florida and the Chesapeake area. The movement may have been facilitated by the change in the paleoclimate during York- town time. The Chesapeake area during early Yorktown time is postulated as being cool with a warming trend upward through Yorktown time (Gibson, 1967; Hazel, 1971), which could have been a cause of decrease in provin- cialism during this time interval. The Waccamaw Formation in North and South Carolina and the Caloosahatchee Formation in Florida are here considered coeval units. All reports of occurrences of pec- tens from the literature and from the USNM collections were noted in order to compare the degree of similarity between the two areas. The Waccamaw Formation, including Croatan Forma- tion at the Lee Creek Mine, contains 11 species of pectens (Ward and Blackwelder, this volume; Dall, 1898:721, 751; Gardner, 1944:31, 34, 36, 39; Mansfield, 1936:181-183; Tucker-Rowland, 1936a:484, 1938:24, 27, 50, 59; Waller, 1969:49, 51, 59): Pecten brouweri Tucker, 1934, P. hemicy- clicus Ravenel, 1834, ""Pecten" holmesii Dall, 1898, Euvola raveneli (Dall, 1898). Argopecten anteamplicostatus (Mans- field, 1936), A. eboreus (Conrad, 1833), A. vicenarius (Con- rad, 1843), Stralopecten ernestsmithi (Tucker, 1931), Lepto- pecten leonensis (Mansfield, 1932), Leptopecten auroraensis Ward and Blackwelder, this volume, and Amusium mortoni (Ravenel, 1844). The Caloosahatchee Formation contains 13 reported spe- cies of pectens (Dall, 1898:721, 728, 731, 742, 757; DuBar, 1958:158-161; Gardner, 1944:30, 31, 36, 39; Mansfield, 1936:181-183; Olsson and Harbison, 1953:53-56; Tucker- Rowland, 1936a:483, 1936b:1010, 1938:25, 27, 28, 34, 39, 59; Waller, 1969:50, 51, 59): Pecten brouweri Tucker, 1934, P. exasperatus (Sowerby, 1843), Euvola raveneli (Dall, 1898), Argopecten anteamplicostatus (Mansfield, 1936), A. eboreus (Conrad, 1833), A. vicenarius (Conrad, 1843), Chla- mys harrisii (Dall, 1898), Stralopecten ernestsmithi (Tucker, 1931), 5. caloosaensis (Dall, 1898), Leptopecten leonensis (Mansfield, 1932), L. wendelli (Tucker, 1934), Nodipecten nodosus (Linnaeus, 1758), and Amusium mortoni (Ravenel, 1844). Of the 11 species of pectens reported from the Wacca- maw Formation and its equivalent in North Carolina, the Croatan Formation, three species are restricted in their known distribution to the Waccamaw. They are Pecten hemicyclicus, "Pecten" holmesii, and Leptopecten auroraensis. All of the remaining eight species are found also in the Caloosahatchee Formation, making a remarkable similarity between the two areas, and indicating very little provin- cialism in the pectinids at this time along the Atlantic Coast between Florida and North Carolina. Thus from the middle Miocene to the early Pleistocene there is an increasing number of species in common between the North Carolina-Maryland and Florida areas. What this means with regard to temperature relationships is somewhat conjectural, but it would appear that the strong provincial- ism between the Chipola and Oak Grove formations with a generally subtropical nature and the Calvert would mark the Calvert as cooler; whether this would be warm temper- ate or cool temperate for the Calvert is unsettled at present. The decreasing provincialism higher in the column, with the Waccamaw fauna having most of its pecten species in common with the Caloosahatchee while the latter still re- tains a subtropical character, suggests a considerable warm- ing of the North Carolina area. DIVERSIFICATION OF THE PECTINIDS The faunal list of pectens from each of the formations gives information on the diversity of one group of mollusks between the more southerly and more northerly parts of the Coastal Plain strata. The surprising observation is that although the Chipola Formation is considered to have been deposited in consid- erably warmer environmental conditions, the number of species of pectens is just one greater than is found in the Pungo River or Calvert formations 500 miles (805 km) to the north. The Oak Grove Formation, which is also consid- ered coeval with the Pungo River-Calvert strata, has one less species than the formations found farther north. Many complex factors are involved in a list of species from a formation, such as the geographic area covered, the availa- bility of outcrops, the variety of facies, and the amount of collecting, study, and publication. With the present infor- mation, however, the common biological phenomenon of 42 increasing numbers of species with decreasing latitude is not observed in the pectens of the Chipola-Oak Grove, Calvert-Pungo River interval. A similar paradoxical situation exists in the Yorktown- Jackson Bluff time interval. The Yorktown Formation in the more northerly area contains nine species of pectens, whereas the equivalent Ecphora and Cancellaria facies ofthe Jackson Bluff Formation in Florida contain only seven spe- cies. However, during deposition ofthe uppermost Pliocene and lower Pleistocene strata the general biologic pattern of more species in the more southerly areas is marginally present, as 1 3 species of pectens are found in the Caloosa- hatchee Formation in Florida, whereas only 1 1 species are found in the Waccamaw-Croatan formations in North and South Carolina. An interesting point is the increasing diversity of the species of pectens with time. Considering the known out- crops of the formations, it is probable that similar numbers of facies are represented at the different time intervals and have been more or less equally studied. Yet, the oldest Miocene assemblages consist of four to six species, increas- ing from seven to nine during Yorktown-Jackson Bluff time, and from 1 1 to 1 3 during Waccamaw-Caloosahatchee time. It is doubtful that these increases are a result of the temperature-diversity relationship, as the Chipola is thought to be as warm as any of the later formations. Increase in diversity upward through the section appears to reflect an increasing diversification ofthe pectens as a group. MORPHOMETRY The morphometry ofthe species of pectens found in the Lee Creek Mine was studied by the use of all suitable valves. In some species the population .sample amounts to 10 or fewer specimens, but in others as many as 90 specimens are available. Approximately 20 morphological characters were measured on each valve, although the number is variable among species because some lack certain characters, such as plicae. The measuring devices and methods employed in this study are similar to those used by Waller (1969). The measurements of the exterior of the valve, except for con- vexity, were determined by placing the specimen on graph paper. The convexity ofthe valves was measured on a glass |)late with the u.se of a large vernier caliper. The widths of the plicae and of the areas between the plicae were taken by vernier calipers, either internally or externally in various species. The number of plicae was counted on the basis that the outermost plica nmst be reflected on the interior ofthe valve and be botinded externally on the disk-flank side by a distinct groove, fhe measurements of the resilial insertion and resilifer were taken through the ocular micrometer of the microscope. MEASLREMENTS AND ABBREVIATIONS.—A selection of SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY HL Q I Q < FIGURE 6.—Diagram of measurements for pectens. (See below for expla- nation of symbols.) Specimens of graduated size is presented at the end of the di.scussion of each species. The arbitrary selection of speci- mens was made on the basis ofthe most nearly complete set of measurements possible on three or four different sized specimens. These data are presented for the Lee Creek specimens, as well as for comparative material of the same or related taxa from the USNM collections. Complete data on the population samples are available from the Depart- ment of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. The var- iates measured and their appropriate abbreviations are as follows (.see also Figure 6): ADHD Anterior dorsal half-diameter of disk AHL Anterior half-diameter of disk BN Depth of byssal notch (;ON Convexity DBN Distance from origin of growth to inner part of byssal notch H Height of disk (linear) HAA Height of anterior auricle HL Total length of hinge line HP Height of plicae HPA Height of posterior auricle MR Height of resilifer HRI Height of resilial insertion I. Length of disk LA A Length of anterior auricle LPA Length of posterior auricle LR Length of resilifer LRI Length of resilial insertion NP Number of plicae NRIB Number of ribs PDHD Posterior dorsal half-diameter of disk PHL Posterior half-diameter of disk NUMBER 61 43 V Valve, left (S) or right (D) Wl Width of interspaces between plicae WP Width of plicae IMPORTANT CHARACTERS.—A small number of charac- ters were found important in characterizing and discrimi- nating various species of pectens from the Miocene and Pliocene strata in the Lee Creek Mine and environs. Al- though internal characteristics were found to be important by Waller (1969), the musculature was not used in the present study because of the difficulty in obtaining a large enough population sample having these characters pre- served. In some species, the interior, and to a lesser extent the exterior, is covered with an indurated matrix, which requires considerable time for each specimen to be cleaned by air abrasive methods. Also the air abrasion process erodes enough of the weakly preserved muscle scars to make ac- curate measurement of them difficult. In other groups that do not have the indurated matrix, the state of preservation on the interior is not sufficient to allow careful study ofthe muscle scar locations. The general morphological charac- teristics of the valve do yield important characterizations and distinctions in all cases. In the Placopecten stock, attach- ment scars in the form of the resilial insertion are used as an important differentiating characteristic. The valve shape among most pectens is similar, and in only two groups in this study could species be differentiated on the basis of valve shape. One is the Placopecten group, where the sample of P. clintonius clintonius from the Lee Creek Mine has an oblique valve outline compared to the Holocene sample of P magellanicus. The other is in the Chesapecten group where C. nefrens differs, from C. coccymelus by having a longer valve in relation to the height. The convexity of the valves varies greatly from genus to genus, but also varies within a species group as shown in the Pecten humphreysii group (Figure 10) and the Argopecten eboreus stock (Figure 14). The byssal notch is important as it may closely reflect anatomical changes. The byssal notch varies phylogeneti- cally within the Chesapecten stock; the early members, such as C. coccymelus and C. nefrens, have deep byssal notches; the next number, C. santamaria, has a notch of moderate depth; the following species, C. middlesexensis, has a slightly shallower notch; and the youngest members, C. jeffersonius and (C. madisonius, have very shallow notches. This character also varies within other species groups or genera as shown in Pecten humphreysii and allies (Figure 9) and the Argopecten eboreus stock (Figure 13). The height and length of the auricles is a variable char- acter within a species group, as shown in Placopecten clinton- ius (Figure 20). The plicae are among the most striking features in many pecten groups, particularly in the Chesapecten group, where they are strongly developed. The number of plicae is a valid and useful characteristic. This chapter is especially useful in the (Chesapecten lineage (Figure 23) and to a somewhat lesser degree in the Argopecten eboreus stock, with its many subspe- cies (Figure 11). Other aspects of ornamentation are also important in the pectens studied herein. These include significant differ- ences in the number of costae on the plicae in the Chesapec- ten group. The number of costae varies from 1 to 4 in C. coccymelus to as many as 20 in C. jeffersonius and C. madison- ius. There also is a significant difference in the number of costae on the auricles with the number varying from as few as 6 in (C. coccymelus to as many as 25 to 30 in C. jeffersonius and (C. madisonius. The arrangement of the internal lirae, which are char- acteristic of Amusium, appears to be diagnostic of several species. This character should be useful in specific identifi- cation as most of the specimens of Amusium are fragmentary. In Amusium the lirae vary from closely spaced pairs with wider areas between pairs to essentially widely and uni- formly spaced lirae. ACKNOWLEDGMENTS The author is indebted to Jack McLellan and Druid Wilson for help in the collection of specimens from the Lee Creek Mine. Linda Larkie and Jeff Lund assisted in the measurement of specimens. The photographs of the speci- mens were taken by Robert McKinney. Jeff Lund prepared the illustrations and assisted in numerous other activities. Warren Addicott, Thomas Waller, and Druid Wilson pro- vided much appreciated critical reviews ofthe manuscript. Muriel Hunter kindly donated specimens from Florida to the USNM collections. Family PECTINIDAE Rafinesque, 1815 Genus Pecten Muller, 1776 Pecten mclellani, new species PLATES 1, 2, 13: FIGURE 2 DESCRIPTION.—Shell Outline: Shell medium to large in size, with specimens having heights of 80 to 100 mm com- mon in the population sample, and reaching a maximum height of 130 mm; slightly longer than high, with a maxi- mum length of slightly greater than 120 mm; right valve low to moderately convex with a maximum convexity of 17 mm; left valve flat to slightly convex with a maximum convexity of 9 nnn; outline of disk equilateral, with almost identical anterior and posterior half-diameters. Auricles and Outer Ligament: Right anterior auricle with a slightly convex surface; dorsal margin slightly dorsal to groove of outer ligament and folded; byssal notch very shallow with broad apex; byssal fasciole poorly developed; ctenolium observable on right valves. Left anterior auricle r ,» .p/ 0 p. Humphreys A P- mclellani J L 10 12 14 lb le WIDTH OF INTERNAL PLICA J L 20 22 24 • • K- • P. hurr,i,hrcys A P 111. Ulhini 10 2U J L J L 30 40 SO WJ 70 SO W 100 110 iiO TiO LINEAR HLIOHT NUMBER 61 45 FIGURE 7 (top left).—Bivariate scatter diagram showing the difference in the width of the internal plica and groove between samples of Pecten humphreysii (Calvert Formation, Maryland) and P. mclellani (Pungo River Formation, North Carolina). FIGURE 8 (bottom left).—Bivariate scatter diagram showing the difference in the width of the internal groove compared to the height of the valve among samples of Pecten humphreysii (Calvert Formation, Maryland) and P. mclellani (Pungo River Formation, North Carolina). FIGURE 9 (right).—Bivariate scatter diagram showing the deeper byssal notch in relation to the length of the anterior outer ligament in a sample of Pecten humphreysii (Calvert Formation, Maryland) compared to P. mclel- lani (Pungo River Formation, North Carolina). FIGURE 10 (below).—Bivariate scatter diagram showing the greater convex- ity of the right valves compared to the height of the valve in a sample of Pecten humphreysii (Calvert Formation, Maryland) compared to P. mclellani (Pungo River Formation, North Carolina). 10 15 20 25 LENGTH OF ANTERIOR OUTER LIGAMENT • P. humphreys A P . mclelUni LINEAR HEIGHT 46 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY with surface nearly planar to slightly convex; dorsal margin slightly folded and nearly coincident with trace of outer ligament; free margin slightly rounded with shallow byssal sinus having a rounded apex. Posterior auricles similar in size to anterior; dorsal margin slightly dorsal to groove of outer ligament and folded; free margin slightly convex, especially near dorsal margin. Posterior and anterior outer ligaments generally about equal in length. Exterior Shell Surface: Both valves with about 12 plicae; in early growth stages plicae defined from interspaces by low, moderately rounded sides until shell heights of approx- imately 50 mm are reached, thereafter plicae becoming less strongly defined from interspaces with very broad, low sides, until becoming obscure at margins of large valves; no secondary radial ornamentation on plicae or interspaces; concentric lamellae well developed on left valves, less so on right valves being primarily preserved on the disk flanks. Anterior and posterior auricles have approximately 8 radial costae, moderately developed on the initial 10 mm of the auricle, becoming obsolete beyond this point; concentric lamellae well developed on auricles. Disk flanks of right valves have 4 moderately developed radial costae on initial 15 nmi along with moderately developed concentric lamel- lae; left valves have smooth disk flanks except for well- developed concentric lamellae. Interior Features: Resilial insertions slightly less than 1 V2 times as high as long, orientation ranging from perpendic- ular to hinge line to slightly sloping either anteriorly or posteriorly; single, strongly developed auricular denticle both anteriorly and posteriorly; additional one or two costae found within the interior plicae. DISCUSSION.—The only closely related species in the Mio- cene strata ofthe Atlantic Coastal Plain is Pecten humphreysii Conrad, which is found in slightly lower beds ofthe Pungo River Formation in the Lee Creek Mine and in the Calvert Formation in northernmost Virginia, Maryland, and New Jersey. Pecten mclellani is distinguished from this species by the ornamentation, position ofthe byssal notch relative to the end of anterior outer ligament, and convexity of the right valve. The number of plicae in P. mclellani is greater, ranging from 10 to 13 in number, while P. humphreysii has from 8 to 10 (7 or 8 broad and prominent ones and two lateral ones quite reduced in size, which arc more prominent on the interior ofthe valve). Pecten humphreysii has much wider plicae on the right valve, with relatively narrower inter- spaces and, correspondingly on the left valve, has relatively narrow plicae with wide interspaces. The plicae on both valves are quite pronounced with vertical sides in some specimens. P. mclellani has considerably narrower plicae on the right valve with the interspaces more nearly approach- ing equal width with the plicae; on the left valve correspond- ingly are wider plicae than in P. humphreysii with narrower interspaces. The plicae are very slightly raised in compari- son with P. humphreysii and do not have the vertical sides common in the latter. Figures 7 and 8 show the significantly greater width of the plicae on the right valves of P. hum- phreysii. (The measurements are taken internally as the sharpness of the plicae is increased on the interior, giving more accurate measurements.) Although the byssal notch is shallow in both species, the position of the notch in relation to the anterior end of the outer ligament is different between the two species (Figure 9). In P. humphreysii the posterior end ofthe byssal notch is 1 to 3 mm posterior to the anteriormost point of the outer ligament. In P. mclellani the posterior end of the byssal notch is from 0.5 mm posterior to almost 1 mm anterior to the anteriormost end of the outer ligament. The right valves of P. humphreysii have considerably greater convexity compared to those of P. mclellani as shown in Figure 10. As P. humphreysii is found in beds of the Pungo River Formation, below those in which P. mclellani occurs, and as the two species have similar morphology, it is considered likely that P humphreysii is ancestral to P. mclellani. One important phylogenetic change between the two species is a decrease in the strength and width of the plicae in the descendant species. Mature specimens of P. humphreysii do show a decrease in the strength of the plicae in the later stages of the valve to a height and sharpness similar to that found in the early stages of P. mclellani. There is a general similarity in the shell shape, ornamen- tation, both internal and external, and byssal characters between P. mclellani and the later occurring Pecten holmesii Dall from the Waccamaw Formation in South Carolina. No related species of an intermediate age is known, and the similarity may not reflect any relationship. An increase in convexity ofthe right valve of P. mclellani, however, along with a further reduction in the largely obscure plicae would give a form similar to that of P. holmesii. Pecten ochlockoneensis Mansfield from the Choctaw- hatchee Formation in Florida and P. smithi Olsson from the Yorktown Formation in Virginia differ from P. mclellani in having many more plicae on both valves and in being much smaller in size. In addition, P ochlockoneensis has a more convex right valve. These two species are most similar to P. mclellani, but are doubtfully congeneric. NAME.—The species is named in honor of Mr. Jack McLellan of Texasgulf Inc., who collected and donated many specimens of pectens and other invertebrates from the Lee Creek Mine. TYPES.—Holotype: right valve, USNM 218830. Figured paratypes: right valve, USNM 218828; right valve, USNM 218829; Icfl valve, USNM 218831; left valve, USNM 218865; unfigured paratypes, USNM 218933, 362976, 362977, 362978, and 362979. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—The only known occurrence of this .species is in the upper part ofthe Pungo River Formation of early middle Miocene age in the Lee Creek Mine in North Carolina. Well-preserved speci- NUMBER 61 47 TABLE 1.—Measurements (in mm) of a representative sample of Pecten mclellani, new species. USNM USNM USNM Character 218828 218830 362976 (D) 52.0 (D) (D) H 110.0 87.0 AHL 28.5 64.0 _ PHL 27.5 63.0 49.0 L 56 127 _ ADHD 27 50 _ PDHD 28 55 42 CON 7.5 17.0 HAA 9.0 18.5 15.0 HPA 11.0 18.0 14.0 LAA 14 30 23 LPA 12.0 26.0 19.0 HL 26.0 56 41 DBN 13.5 29.5 23.5 BN 0.5 0.5 -0.5 WP 2.8 7.2 7.7 Wl 3.3 6.4 4.6 NRIB 12 13 13 mens are found in the upper 6-12 feet (1.8-3.7 m) (units 4-7 of Gibson, 1967) ofthe Pungo River Formation, some being found just an inch (2.5 cm) below the contact with the overlying Yorktown. This mine contains the only known outcrop of this formation in North Carolina, the formation being limited to the subsurface except for this artificial exposure. Strata of this age containing calcareous fossils do not naturally crop out south of north central Virginia. MEASURED MATERIAL.—Total specimens measured in- clude: 3 right valves and 1 left valve from USGS 25743 and 3 right valves and 1 left valve from USGS 25757. A popu- lation sample from the Pungo River Formation at Lee Creek Mine, USGS 25743 and 25757, consisfing of 8 specimens, 6 right valves and 2 left valves, was measured. Measure- ments of a representative sample of 3 specimens are given in Table 1 (USNM 218830, holotype, and USNM 218828, both from USGS 25743; USNM 362976 from USGS 25757). Pecten humphreysii humphreysii Conrad PLATE 3: FIGURES 2-7; PLATES 4, 5: FIGURES 1, 2, 4; PLATE 6: FIGURES 5, 7 Pecten humphreysii Conrad, 1842:194, pl. 2: fig. 2.—Mongin, 1959:297- 299, pl. 25: figs. la-b. Vola humphreysi (Conrad).—Whitfield, 1894:32-34, pl. 4: figs. 6-9. Pecten {Pecten) humphreysii Conrad.—Glenn, 1904:372, pl. 98: figs. 10-12— Schoonover, 1941:188-190, pl. 20: figs. 1-2. Pecten (Pecten) humphreysi Conrad.—Tucker, 1936a:478-479, pl. 3: fig. 3; pl. 4: fig. 10. DESCRIPTION.—Shell Outline: Shell medium to large in size, reaching a maximum height of 115 mm; slightly longer than high, with a maximum length of 127 mm; length to width ratio increases slightly with ontogeny; right valve moderately convex with maximum convexity of 26 mm; left valve planar to slightly convex in a few specimens; outline of disk equilateral with almost identical anterior and poste- rior half-diameters. Moderately developed disk gape both anteriorly and posteriorly, amounting to approximately a 4 to 5 nnn gape in shells slightly greater than 100 mm in height. Auricles and Outer Ligament: Right anterior auricle with strongly convex surface, being raised as much as 6 mm above the plane of commissure in large valves; dorsal margin slightly dorsal to groove of outer ligament and slightly to moderately folded, increasing in degree toward anterior part; byssal notch very shallow with broad, rounded apex; byssal fasciole poorly developed; ctenolium of 3 teeth oc- casionally observed in very young stages. Left anterior auricle with strongly concave surface; dorsal margin slightly folded and nearly coincident with trace of outer ligament; free margin rounded with shallow byssal sinus having a rounded apex. Posterior auricles similar in size to anterior; surface planar to slightly convex; dorsal margin slightly dorsal to groove of outer ligament and slightly to moder- ately folded; free margin straight to slightly convex. Poste- rior and anterior outer ligaments generally about equal in length. Auricular gape relatively large both anteriorly and posteriorly, reaching 4 mm in the largest specimens. Exterior Shell Surface: Both valves with about 8 to 9 plicae. Right valves have broad plicae with relatively narrow- interspaces, with ratio of width of plicae to width of inter- spaces of 20-30 to 1; in early growth plicae sharply defined from interspaces with sides of plicae at angle of about 60 degrees lo surface of valve; in later stages plicae of large valves greater than 88 mm height, sides of plicae make low angles of about 20 degrees to valve surface, giving low and poorly defined plicae at the valve margins. Left valves have narrow plicae with wide interspaces; plicae are sharply de- fined from interspaces in early stages, becoming less sharply defined at shell heights of about 80 mm. Secondary radial ornamentation of 4 to 10 costae of varying strengths and widths on plicae of right valves; plicae on left valves rarely have 2 radial costae; no radial ornamentation in interspaces of either valve. Concentric lamellae moderately developed on right valves, both in interspaces and on plicae; lamellae more strongly developed on interspaces and plicae of left valves. Anterior and posterior auricles of right valves have 8 to 14 radial costae, which vary in strength and spacing and become obsolete about 25 mm from origin of growth; both auricles of left valves have fewer costae, about 6 to 8, which have a more regular development but also become obsolete about 25 mm from the origin of growth; concentric lamellae well developed on all auricles. Disk flanks of right valves have 5 to 8 moderately developed radial costae, which become obscure towards ventral margins, and well-devel- oped concentric lamellae; disk flanks of left valves have 3 to 5 weakly developed radial costae, which become obscure 48 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY towards ventral margins, and well-developed concentric lamellae. Interior Features: Resilial insertion elongated perpendic- ular to hinge line, being about twice as high as long; single auricular denticle strongly developed both anteriorly and posteriorly; single weakly developed costae within the inte- rior plicae. DISCUSSION.—As mentioned under P mclellani, P. hum- phreysii differs from the former by having fewer plicae on the right valve, which are wider and much more pro- nounced, fewer, much narrower, and more pronounced plicae on the left valve, a deeper byssal notch, and a consid- erably greater convexity of the right valve as shown in Figure 10. The surface of the right anterior auricle in P. humphreysii is also more strongly convex. In addition, sec- ondary radial ornamentation of costae on the plicae and auricles of the right valve is better developed in P. hum- phreysii, both in coarseness and extent (Plate 3:figures 1, 2, 4). The costae on the valves of P humphreysii are variable in development; but the absence of costae on the plicae of right valves in many larger specimens is probably a result of wear. Typical specimens of P humphreysii with approximately 8 or 9 broad, pronounced plicae are confined to the phos- phatic and dolomitic layers in the lower and middle part of the Pungo River section and to the lowermost part of the overlying interbedded phosphatic sand and limestone se- quence. On the other hand, P. mclellani is found only in the upper sequence. Only one specimen of P. humphreysii was obtained from possibly the upper part of the Pungo River section, that being a young individual found as float (Plate 3: Figure 5). The vertical change suggests that either there is (1) an evolutionary development during this interval from P. humphreysii to P. mclellani or (2) the environmental changes between the beds are reflected in the occurrences of the two species. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—This sub- species is doubtfully present in the uppermost 3-6 feet (0.9- 1.8 m) (units 6 and 7 of Gibson, 1967) ofthe Pungo River Formation in the Lee Creek Mine, being represented by a single well-preserved individual not collected in place, but possibly from unit 6 or 7 because of color and preservation. In the lower part of the interbedded limestone and phos- phatic sand horizon (unit 4), however, specimens become more common and are quite common as molds and casts in the pho.sphatic intervals below this (units 1-3). Many ofthe phosphatic molds and casts are found in ore piles derived from the more phosphatic beds that are void of original calcareous material. This subspecies is found also in the lower and middle parts of the Calvert Formation in Maryland, being moder- ately common in bed 10 and lower beds. The typical form and an additional subspecies, P. humphreysii woolmani Heil- prin, have been described from outcrops of the Kirkwood Formation and subsurface Miocene in New Jersey (Richards and Harbison, 1942:186). An examination ofthe material in the USNM collections ofthe National Museum of Natural History would place all specimens from New Jersey into P. humphreysii woolmani. Banks and Hunter (1973:359) report P. humphreysii from the Torreya Formation of early Miocene age from the northwestern part of Florida. Hunter kindly sent specimens for examination, and three are illustrated in Plate 4: figures 4-6. The fragments of the left valves agree closely with TABLE 2.—Measurements (in mm) of a representative .sample of Pecten humphreysii humphreysii. Character USNM 218838 USNM 362980 (D) USNM 362981 (D) USNM 362982 (D) USNM 362983 (S) USNM 362984 (S) USNM 362985 (D) (S) (S) H 115.0 112.5 69.0 51.0 29.0 49.0 66.0 33.0 AHL 66 62 36 29 15 25 35 16 PHL 61.0 61.0 40.0 27.0 15.5 27.0 34.0 17.0 L 127.0 123.0 76.0 56.0 30.5 52.0 69.0 33.0 ADHD 55 54 37 28 17 24 17 PDHD 60 55 36 28 16 24 - 16 CON 25.6 - - 12.4 7.5 - - HAA 21.0 21.0 16.0 11.0 6.5 13.0 16.0 8.0 HPA 24 22 16 13 7 12 15 8 LAA 35.U 32.5 - 18.0 10.0 15.0 8.0 LPA 31.0 32.5 21.0 16.0 - 15.0 10.0 HL 66 65 - 34 - 30 18 DBN 32.0 - 22.5 15.5 8.0 - - BN 3.0 - - 2.5 2.0 - - WP 9.1 22.5 0.9 4.4 3.5 3.0 3.1 1.5 Wl 22.7 8.8 4.9 3.6 2.3 7.5 7.9 8.6 NRIB 10 9 10 10 8 9 10 7NUMBER 61 49 specimens of P. humphreysii humphreysii from Maryland as does the largest right valve (Plate 4: figure 4). The other two right valves are of immature individuals and have more sharply raised plicae with essentially vertical sides. A pro- nounced development of the plicae in the early stages with a general rounding of the edges of the plicae during ontog- eny is commonly found in larger specimens of P. humphreysii humphreysii from Maryland, and the Florida specimens are placed in this subspecies. The occurrence in Florida of P. humphreysii is by far the farthest southern limit for this species. According to Banks and Hunter (1973) the Torreya Formation is found in the Gulf trough opening through the southeast Georgia embay- ment into the Atlantic Ocean. This opening would give a fairly direct migration route between the area of the Tor- reya Formation in Florida and areas farther north along the Atlantic Coast, such as the Lee Creek Mine in North Carolina and Maryland. The Torreya Formation is placed in the N5 or N6 plank- tonic zones of early Miocene age by Banks and Hunter (1973). Bed 10 of the Calvert Formation at Plum Point, Maryland, and the upper part of the Pungo River Forma- tion in the Lee Creek Mine are placed in planktonic zones N8 or N9 by Gibson (1967; 1983b:360), making the Florida specimens the oldest known of this species along the Atlantic and Gulf Coast. Grant and Gale (1931:222) and Fleming (1957:16) sug- gested that the Pecten humphreysii group migrated, probably during the Miocene or Pliocene from Maryland via Califor- nia to Japan where it persists as Pecten albicans Schroter. MEASURED MATERIAL.—A population sample from the Calvert Formation at the Basford Farm, USGS localities 23565 and 25744, and Howard Post Office, USGS locality 10278, consisting of 66 specimens, 24 right valves and 42 left valves, was measured. Measurements (in mm) of a representative sample of 8 specimens are given in Table 2 (USNM 218838 is from USGS locality 23565, USNM 362980 through 362985 are from USGS locality 25744). Pecten humphreysii woolmani Heilprin PLATE 3: FIGURE 1, PLATE 5: FIGURE 3, PLATE 6: FIGURES 1-4, 6, PLATE 17: FIGURE 2 Pecten Humphreysii var. Woolmani Heilprin, 1888:405. Pecten (Pecten) humphreysi woolmani Heilprin.—Tucker, 1936a:479-480, pl. 4: fig. 11. Pecten humphreysii woolmani Heilprin.—Richards and Harbison, 1942:186, pl. 8: figs. 12-13, pl. 9: fig. 2. DESCRIPTION.—Except for a few almost complete valves of immature individuals, the samples are composed of frag- mented specimens and a complete description and biometric studies are not possible. Shell Outline: Shell medium to large in size, with frag- ments suggesting valve heights of greater than 100 mm; right valves moderately to strongly convex; left valve planar; outline of disk equilateral. Auricles and Outer Ligament: Right anterior auricle with essentially planar surface; dorsal margin slightly dorsal to groove of outer ligament and folded; byssal notch shallow with broad, subrounded to angular apex; byssal fasciole poorly developed. Left anterior auricle with slight to mod- erately concave surface; dorsal margin nearly coincident with trace of outer ligament and slightly folded; free margin slightly rounded with shallow byssal sinus having a sub- rounded apex. Posterior auricles similar in size to anterior; surfaces planar; dorsal margins nearly coincident with trace of outer ligament and folded; free margins planar and slightly rounded. Posterior and anterior outer ligaments generally about equal in length. Exterior Shell Surface: Both valves with 7 or 8 plicae. Right valves have broad plicae with relatively narrow inter- spaces, with ratio of width of plicae to width of interspaces of 2.5-3 to 1; in early growth stages plicae sharply defined with vertical to overhanging sides; in later stages plicae still have almost vertical sides. Left valves have narrow plicae with wide interspaces; plicae have sharply defined sides throughout growth, although becoming less so in later stages. Secondary radial ornamentation of 10 to 15 costae of relatively uniform development on plicae of right valves; plicae on left valves lack costae; occasional radial costae on interspaces of right valve (Plate 6: figure 1). Concentric lamellae moderately developed on right valves, both in interspaces and on plicae; lamellae more strongly developed on interspaces and plicae of left valves. Anterior and pos- terior auricles of right valves have about 12 to 18 weak radial costae, which become obsolete about 30 mm from origin of growth; auricles of left valves have fewer costae, about 8 to 10, weakly developed, which quickly become obsolete; concentric lamellae well developed on all auricles. Disk flanks of right valves have numerous fine radial costae, which become weaker anteriorly, but persist; as many as 25 costae on the posterior flank and about 10 slightly coarser costae on the anterior flank; both flanks have moderately developed concentric lamellae; left valves have about 5 fine costae on each flank and well-developed concentric lamel- lae. Interior Features: Resilial insertion elongated perpendic- ular to hinge line, being about twice as high as long; single auricular denticle, moderately developed both anteriorly and posteriorly. DISCUSSION.—Specimens of P. humphreysii occurring in New Jersey were separated by Heilprin (1888:405) as "a variety or subspecies" on the basis of having greater height of the auricles, having a more distinct quadrangulation of the plicae on the convex valve, and having more prominent striations on the plicae. Whitfield (1894:33) did not believe 50 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY the auricular characters differed between the two forms, but he did not have a complete valve from New Jersey to examine. Whitfield mentioned a considerably larger size for the New Jersey specimens, up to approximately 5 inches (12.7 cm) (based upon projections from incomplete valves), but specimens of such size from Maryland are in the USNM collections at the National Museum of Natural History. Tucker (1936a, pl. 4: fig. 11) figured a specimen she took as the neoholotype of P. humphreysii woolmani. It is a partial left valve and, along with relatively pronounced plicae, has a slight sulcus developed on the summit of the plicae. This sulcus was not observed on plicae on left valves of the numerous specimens in the USNM collections. An examination ofthe specimens of P. humphreysii wool- mani in the USNM collections, which number more than 50 fragmented valves, shows the prominent quadrangula- tion ofthe plicae mentioned by Heilprin (1888:405) to be a consistent feature of the right valves. Compared with the great majority of specimens from Maryland, the plicae on the right valves ofthe specimens from New Jersey are much more sharply delineated from the interspaces, having essen- tially vertical to overhanging sides on the plicae compared to sloping sides in the majority of the specimens from Maryland (Plate 3: figure 1). The specimens from New Jersey also have more sharply defined and higher plicae on the left valves. Other differences between the two subspecies include the following: Pecten humphreysii woolmani has a more convex right valve as deduced from the fragments of larger valves; is lacking the convexity of the right anterior auricle; generally has one or two fewer plicae, which are slightly broader; has weaker auricular denticles; and has more numerous radial costae developed on the plicae, au- ricles, and disk flanks in addition to the presence of an occasional costae in the interspaces. Within a single population sample of P humphreysii hum- phreysii from Maryland, a few valves fall within the range of ornamentation found in the specimens from New Jersey. They show a tendency toward quadrangulation ofthe plicae and development of more costae, but do not reach the development ofthe typical specimens. The geographic sep- aration ofthe areas ofthe two morphotypes, with probably 90 percent of the population sample in each area being compo.sed of one form, suggests that they are valid geo- graphic subspecies with some mixing in the area of overlap. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—This sub- species has been recorded only from the Kirkwood Forma- tion of New Jersey, which is considered equivalent to the Calvert Formation in Maryland. MEASURED MATERIAL.—Total specimens measured in- clude 2 left valves (USNM 218847 and USNM 362986) from USGS locality 2106, Kirkwood Formation, marl beds near Jericho, Cumberland Company, New Jersey. Their measurements are given in Table 3. TABLE 3.—Measurements (in mm) of a representative sample of Pecten humphreysii woolmani. Character USNM 218847 (S) USNM 362986 (S) H 33 26 AHL 16 13 PHL 16 12 L 32 25 HAA 9.5 7.0 HPA 9.0 7.0 LAA 8 LPA 7 HL 15 DBN - BN - ADHD - PDHD - - CON - - WP 4.8 3.8 Wl 1.3 1.0 NRIB 7 8 Genus Argopecten Monterosato, 1889 Argopecten eboreus (Conrad) Pecten eboreus Conrad, 1833:341. Pecten (Plagioctenium) eboreus Conrad.—Dall, 1898:749 [in part]. Chlamys (Plagioctenium) eboreus (Conrad).—Tucker-Rowland, 1938:40-41, pl. 3. fig. 12. Chlamys (Aequipecten) eborea (Conrad)—Gardner, 1944:36-37, pl. 7: figs. 1, 5. 6. a [in part]). Argopecten eboreus (Conrad).—Waller, 1969:59-61, pl. 5: fig. 14. DISCUSSION.—This species is very common in the later Cenozoic strata of the Atlantic Coastal Plain. Its oldest occurrence is in the basal Yorktown Formation (= "Virginia St. Marys" beds of Mansfield) of late Miocene age in Vir- ginia, and it ranges into strata of Pleistocene age in Florida (Waller, 1969:60). Many morphologic variations are pres- ent, and these have been made into a number of subspecific taxa. Some of the subspecific characters are found only in a single group, but generally there is a complex mixture of the mor])hologic characters with some of the diagnostic subspecific characters being found in varying combinations. The morphologic variation in this complex of subspecies led Gardner (1944:36) and Waller (1969:60) to place all the forms into a single species group without trying to apply the subspecific names. The earliest subs]5ecies, A. eboreus urbannaensis (Mans- field), from the lowermost part ofthe Yorktown Formation in Virginia, is readily .separable on morphologic criteria; but in the middle and upper parts of the Yorktown For- mation a group of names is available. These include A. eboreus eboreus (Conrad, 1833), originally described from the Yorktown Formation at Suffolk, Virginia, A. eboreus NUMBER 61 51 darlingtonensis (Dall, 1898), described from the Duplin Marl near Darlington, South Carolina, A. eboreus watsonensis (Mansfield, 1936), described from the Ecphora zone ofthe Jackson Bluff Formation in Florida, A. eboreus solarioides (Heilprin, 1887), from the Caloosahatchee Marl of Florida, A. eboreus bertiensis (Mansfield, 1937), from the upper York- town beds at Mt. Gould Landing in North Carolina, and A. eboreus senescens (Dall, 1898), described from the Wacca- maw Formation in South Carolina. Argopecten e. darlingtonensis (Dall) was characterized by radial threads towards the margin ofthe disk (plate 9: figure 1), along with 21 to 24 well-marked, angular plicae. How- ever, in comparing the suite of type material of A. e. dar- lingtonensis with population samples from Suffolk, Virginia, the type area for A. e. eboreus, the specimens from the Suffolk area also have marginal threads on many specimens along with a similar number and character ofthe plicae. On these characteristics and a general overall morphologic sim- ilarity, it would seem that these two subspecies, at least from their type areas, are synonymous. A variety of forms are labeled A. e. darlingtonensis in the USNM collections, and some of these undoubtedly belong to other members ofthe A. eboreus complex. Mansfield (1936:184) placed A. e. dar- lingtonensis in the phylogenetic development of A. eboreus as a time equivalent subspecies to A. eboreus eboreus, and leading to A. e. solarioides, but it is uncertain what specimens he was considering. The specimen illustrated by Mansfield (1932, pl. 12: fig. \)ds A. e. darlingtonensis fror\Mhe^V\ocene of Florida appears to be related to A. e. solarioides. It would be difficult, however, to place this specimen within the variation found in the type suite and other samples from South Carolina. A. eboreus watsonensis (Mansfield) was distinguished by having 18, nearly flat, nearly smooth plicae. Specimens belonging to this general morphologic type were reported by Mansfield (1936) to occur in strata of Pliocene age in Florida and also in Mansfield's zone 1 of the Yorktown Formation in Virginia and North Carolina, and this mor- phologic group could be identified in the present study. A. eboreus bertiensis (Mansfield) differs in having a very convex left valve, and having an incised groove on the plicae of both valves. In an examination of the type suite and topotype material, the high convexity ofthe left valve is a constant characteristic, but the incised groove, although found on many, is not present on all the specimens. This subspecies has been found up to now only at the type locality and at Colerain Landing, a short distance farther north on the Chowan River. A. eboreus solarioides (Heilprin) was characterized as hav- ing right valves with approximately 20 broad, squarish plicae with narrow interspaces bearing radial striae. The number of striae vary in number from one to two in samples from different localities. Although striae occur in the inter- spaces on the right valve, they are most commonly found on the left valve. The squareness of the plicae varies from very square to moderately rounded in samples from south- ern Florida, although the form with squared plicae is the dominant one. This subspecies is found in the Caloosa- hatchee Formation in Florida, and also probably occurs in the Waccamaw Formation in North and South Carolina. A. eboreus senescens (Dall) was distinguished on the basis on having about 23 plicae, which become obscure in the later ontogenetic stages. This subspecies has been reported from the Waccamaw Formation in North and South Caro- lina. Pecten yorkensis was described by Conrad (1867) from the Yorktown Formation at Yorktown, Virginia. A single left valve (ANSP 38007) labeled Pecten yorkensis is in the collec- tions at the Academy of Natural Sciences at Philadelphia and is chosen as the lectotype (Plate 9: figure 5). This specimen closely matches the dimensions and number of plicae given in the original description. Although some workers (e.g., Mansfield, 1936:179, Tucker-Rowland, 1938:38) have considered P. yorkensis to be a valid subspe- cies of Argopecten eboreus, this specimen appears to fall within the range of variation of i4. e. eboreus. There is considerable variation within the population samples of A. eboreus. Some populations include diagnostic characteristics of several subspecies within a single sample. The complex morphologic intergradation in the A. eboreus group needs a similar treatment to that given the A. gibbus stock by Waller (1969). However, a stratigraphic succession among some subspecies can be recognized. The earliest subspecies, A. e. urbannaensis, is easily differentiated (there is some question whether this is the basal stock or even a member of A. eboreus). This subspecies occurs in the basal part of the Yorktown Formation in Virginia (includes the upper part of the "Virginia St. Marys" beds of Mansfield). Occurring above this stratigraphically in the beds of zone 1 ofthe Yorktown of Mansfield (1944) are the forms referred to here as A. eboreus aff. A. e. watsonensis. In the overlying zone 2 of the Yorktown Formation is typical A. e. eboreus, which also would include at present A. e. darlingtonensis and A. e. yorkensis. Stratigraphically above, at least in the upper beds of the Yorktown Formation along the Chowan River in North Carolina, is A. e. bertiensis. This subspecies occurs in the lowest beds exposed at Mt. Gould Landing; but the strata 10 feet (3 m) higher in the section, which would be the upjDermost part ofthe Yorktown Formation, have forms closely approaching A. e. solarioides, along with an occasional A. e. bertiensis. The highest group in the sequence is A. e. solarioides, which occurs in the Waccamaw Formation in North and South Carolina and the Caloosahatchee Forma- tion in Florida, containing in a few places a component of A. e. senescens as a part ofthe population structure. General characteristics noted during study and measure- 52 SMITHSONIAN CONTRIBU I IONS TO PALEOBIOLOGY D D A. eboreus aff. A. eboreus watsonens Lee Creek Mme A. eboreus aff. A. ebor Lee Creek Mine Watson's Lariding, Fla. \. eboreus bertiensis Mt. Gould Landing, N. C. n fJUMBEH OF PLICAE l-K.t Kt 1 I. — Double-sidod h.ii graph ol ihe MUMIIHI ol plu.K- in five suhgioupnigs ol .Argopecten thoreus r A A. eboreus aff. A. eboreus i vat sone nsis Lee Creek Mine A. eboreus aff. A. eb..reus sol ano des Lee Creek M.ne o - m A. eboreus watsonensis Watson's Landing, Fla. A ^0 . o o ° o o A. eboreus bertiensis o A Ml. Gould Landing, N. C. ', A. eboreus urbannaensis Urb.inna, Va. ■■ O O 0 ■■Q "-^ " , * ,-,0 o S ■ ■ o O ■ ■|- ■ 0 o ■ O A r. ■ ■ o - 1 8 o«i, A ' m ■ ■ 1 1 ■ ■ ■ 1 A ■ ■ ■ ■ I iB ■ ■ ■ ■ ■ 1 1 1 1 VICJIH Cf 111 I t MfJM PI |( Fu.t'KK I L'. — Biv.ii i.ile Sf.illcf (li.igi.Mii showing ihc gciu r.il siniiLit ii\ ol llic uuith o( IIR- iiuci ri.il pli( ,i .uui gloo\»- III \,illous Mihgi oiipmgs oi .\rgiipi'fh'n lixiri'iis. NUMBER 61 53 ment of the A. eboreus complex include the following: All forms have a slightly longer posterior half diameter than anterior. The convexity of the left valve is more variable within the species complex than that ofthe right valve, but the left valve is always more convex than the right. The number of plicae varies from about 16 to 25 (Figure 11), but the width of the internal plicae is always greater than the width of the adjacent groove. Moreover, regardless of the number of plicae and grooves, the ratio ofthe width of the internal plicae to the width of the internal groove is e.s.sentially constant between forms (Figure 12), indicating a preferred ratio, which may reflect the strongest way of constructing the shell. The depth of the byssal notch be- comes shallower through the stratigraphic sequence de- scribed above of A. e. urbannaensis to A. e. solarioides (Figure 13), except for the reversal in the sample of A. e. aff. A. e. solarioides from the Lee Creek Mine. LECTOTYPES.—In addition to the lectotype designated for Argopecten eboreus yorkensis, ANSP 38007, left valve, Yorktown Formation, Yorktown, Virginia, lectotypes also are selected for 3 additional taxa. A lectotype is selected for A. eboreus darlingtonensis: right mm 11 r- 10 A. eboreus aff. A. eboreus watsonensis Lee Creek Mine A. eboreus aff. A. eboreus solarioides Lee Creek Mine A . eboreus watsonensis Watson's Landing, Fla. A. eboreus bertiensis Mt. Gould Landing, N.C. A. eboreus urbannae Urbanna, Va. O ▲ ▲ ▲ o O S O O O ■OB O O 60 LENGTH OF VALVE FIGURE 13.—Bivariate scatter diagram showing the differences in the depth ofthe byssal notch in relation to the length ofthe valve in various subgroupings of Argopecten eboreus. 54 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY valve, USNM 145432, from the Duplin Formation at USGS 2025 (Plate 9: figure 1). This is part ofthe type material, and is one of the cotypes selected by Tucker-Rowland (1938:42). The other cotype, a left valve, becomes a lecto- paratype, USNM 218934. An additional lectoparatype is illustrated (Plate 9: figure 4). A lectotype is selected for A. eboreus urbannaensis: right valve, USNM 370829, from the basal Yorktown ("Virginia St. Marys" bed) at USGS 3915 (Plate 11: figures 1, 3). This valve is one of the cotypes. The other cotype, a left valve, USNM 218862 (Plate 11: figure 4), becomes a lectopara- type. A lectotype is selected for yi. eboreus bertiensis: right valve, USNM 496224, from the Yorktown Formation at USGS 1 1999. This valve is one of the cotypes (Mansfield, 1937, fig. 1). The other cotype, a left valve, USNM 218935, becomes a lectoparatype. Argopecten eboreus aff. A. eboreus watsonensis (Mansfield), new combination PLATES 7, 8, PLATE 10: FIGURE 4 Pecten (Chlamys) eboreus watsonensis Mansfield, 1936:188. DESCRIPTION.—Shell Outline: Shell of medium size, at- taining height of 80 mm; left valve of low to moderate convexity and only slightly more convex than right valve. Outline of disk equilateral; disk flanks very low. Disk gapes narrow. Auricles and Outer Ligament: Right anterior auricle with almost planar to slightly convex surface; dorsal margin slightly dorsal to groove of outer ligament, sharply folded and thickened; folding of dorsal margin increases in amount away from origin of growth; byssal notch moderately shal- low, with angular to rounded apex; byssal fasciole moder- ately broad and slightly arched adjacent to suture and planar away from suture; ctenolium of 3 teeth in specimens up to 60 mm height, occasionally 1 tooth visible in specimens up to 80 mm height. Left anterior auricle with moderately concave surface; dorsal margin flat and nearly coincident with trace of outer ligament; free margin slightly rounded with shallow byssal sinus having a rounded apex. Posterior auricles similar in size to anterior; right posterior has planar to slightly convex surface with dorsal margin dorsal to groove of outer ligament and folded more strongly away from origin of growth; left posterior auricle has concave surface with dorsal margin nearly coincident with trace of outer ligament. Posterior and anterior ligaments generally about equal in length. Exterior Shell Surface: Number of plicae on valves varies from 16 to 19, with 18 being most common; plicae are low in early growth stages but sides are relatively steep, with plicae remaining low in later stages but sides becoming rounded; plicae wider than interspaces. Occasionally 3 or 4 costae on the plicae and 1 or 2 in the interspaces, but most specimens smooth. Concentric lamellae weakly developed on interspaces and plicae of both valves. Right anterior auricle has about 5 costae of moderate strength, left anterior about 8; both posterior auricles have about 10 weakly developed costae; concentric lamellae moderately devel- oped on auricles. Disk flanks have moderately developed concentric lamellae and occasionally 2 or 3 weak costae. Interior Features: Resilial insertion about as long as high, orientation ranging from perpendicular to slightly posterior slant; single, weakly developed auricular denticle both an- teriorly and posteriorly. DISCUSSION.—Mansfield (1936:188) characterized/i. ebo- reus watsonensis as having "18 nearly flat, nearly smooth, moderately narrow ribs separated by spaces about as wide as ribs' and differing from A. e. eboreus "in having 5 to 8 fewer, more widely spaced ribs." The specimens from Lee Creek resemble the specimens of A. e. watsonensis from Florida in having the same number of plicae, a similar development of the plicae into more squared profile in the higher, float specimens, and in having the same width of the internal plicae and grooves. They differ in having a less convex right valve and a slightly deeper byssal notch. Thus, for now, they will be treated as having affinities to the Florida subspecies as they are gen- erally similar in morphologic characteristics and occur in a similar stratigraphic interval. The specimens collected at Lee Cheek support Mansfield's statement (1936:184) that there is an additional form of A. eboreus between A. e. urbannaensis from the lowermost part of the Yorktown Formation ("Virginia St. Marys' beds of Mansfield) and the typical A. e. eboreus of the younger Yorktown around Suf- folk, Virginia. The specimens from the Lee Creek Mine have 16 to 19 |)licae, with most having 18 (Figure 11). Development of the plicae ranges from relatively low and rounded, partic- ularly in the specimens collected in place in unit 3 of the Yorktown (Plate 7: figures I, 4), to moderately high and squared, most common in the float specimens, which come from higher units, probably units 4 and 5 (Plate 7: figure 2). Ihe left valve has an approximately median convexity for the A. eboreus group, being more convex than .4. e. urbannaensis and most convex in A. e. solarioides, but less convex than A. e. bertiensis (Figure 14). The right valve is moderately convex, being approximately the same as A. e. urbannaensis and A. e. solarioides and more convex than A. e. bertiensis. The result for the two valves is that the left valve is only slightly more convex than the right, the closest to equal convexity of any sample of A. eboreus herein stud- ied. The type specimen of A. e. watsonensis and other spec- imens from Florida differ from the North Carolina speci- mens in having a considerably more convex right valve. A A. eboreus aff. A. eboreus wats Lee Creek Mine onensi. O rt. eboreus ttff. A. eboreus sola Lee Creek Mine ioides B A eboreus watsonensis Watson's Landing, Fla. D A eboreus bertiensis Mt. Gould Landing, N.C. 0 H eboreus urbannaensis Urbanna, Va. °§ •♦ (open symbols denote right valves, closed symbols denote left valves) nDLJ D a. □ D 7, D ''A A. ♦o ♦ ♦ • n o A CONVEXITY FIGURE 14.—Bivariate scatter diagram showing the differences in convexity of the left and right valves among the various subgroupings of Argopecten eboreus. A • A. A. eboreus aff. A- eboreus watsonensis Lee Creek Mine eboreus aff. A. eboreus solarioides a A A. Lee Creek Mme eboreus watsonensis Watson's Landing, Fla. Mt. Gould Landing, N.C. * « Urbanna, Va. - A A A • • • •• • • • • • A • • A A • A D * D • V • DO • 4 D D • ♦ • ♦ ♦ D - A • A/. :' °v A u a • A a° a a 1 1 1 1 □♦ a 1 ♦ D 1 1 1 1 1 10 20 30 40 50 60 70 80 90 100 uo 120 FIGURE 15.—Bivariate scatter diagram showing the differences in the width of the internal groove in relation to the height ofthe valve in various subgroupings of Argopecten eboreus. 56 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY In the Lee Creek specimens the width of the internal plicae is greater than the width of the internal groove (Figure 12). The width ofthe internal groove compared to the height of the valve is markedly different between the Lee Creek specimens and those from Florida (Figure 15). The Lee Creek specimens have approximately the same length ofthe anterior and posterior auricles, but the height ofthe posterior auricles is greater than that ofthe anterior auricles. The specimens from the Lee Creek Mine can be differ- entiated from the stratigraphically lower A. e. urbannaensis by a shallower byssal notch (Figure 1 3), fewer but better developed plicae (Figure 5), wider internal grooves (Figure 15), a relatively shorter anterior auricle and lower posterior auricle, and a greater convexity of the right valve (Figure 14). STRATIGRAPHIC AND GEOGRAPHIC RANGE.—Specimens of A. eboreus aff. A. eboreus watsonensis were collected in place in unit 3 ofthe Yorktown Formation in the Lee Creek Mine, and in spoil material having an indurated matrix, which places the specimens as coming from units 4 and 5 of the Yorktown Formation. Units 3-5 ofthe Yorktown For- mation in the Lee Creek Mine belong to the lowest part of Mansfield's zone 2 ofthe Yorktown. A. eboreus watsonensis was described by Mansfield (1936:188) from the Ecphora zone of the Jackson Bluff Formation in Florida, and was also listed from several localities in zone 1 ofthe Yorktown Formation in Virginia. MacNeil (in Bergendahl, 1956:76) listed specimens from the Tamiami Formation in central Florida as having affini- ties to A. eboreus watsonensis, and additional closely related specimens exist in the USNM collections. These specimens are not typical A. eboreus watsonensis, but are clo.ser to this subspecies than to any other in the A. eboreus stock. The age relationship of A. eboreus watsonensis and those speci- mens having affinities with it is relatively clo.se according to our current understanding of regional stratigraphy. They occur in the Ecphora zone, upper lower and lower middle parts of the Yorktown, and Tamiami formations. Fxcept for A. eboreus urbannaensis, this group is the earliest member of y4. eboreus and looks like an ancestral form for the later subspecies. MEASURED MATERIAL.—Total specimens measured ol Argopecten eboreus aff. A. eboreus watsonensis include 6 right valves and 3 left valves from USGS 25746 and 7 right valves and 9 left valves from USGS 25338. A population sample from the Lee Creek Mine, North Carolina, Yorktown For- mation, USGS 25746 (in situ), and US(iS 25338 (spoil bank), consisting of 13 right valves and 12 left valves, was measured. Measurements of a representative sample of 7 valves are given in Table 4. The measurements for the holotype of Argopecten eboreus watsonensis, USNM 371 139, fiom USGS 10962, Choctawatchee Marl, Watsons Landing, Liberty County, Florida, are given in Table 5. Total specimens measured of Argopecten eboreus urban- naensis include 1 right valve and 5 left valves (USNM 218862, 370829, 362991) from USGS 3915 and 11 right valves and 1 left valve (USNM 362990) from USGS 23468. The specimens from USGS 3915 are from the lowermost part of the Yorktown Formation (= "Virginia St. Marys'" beds of Mansfield) on the river front at Urbanna, Middlesex County, Virginia. Those from USGS 23468 are float from the beach ofthe Rappahannock River from Urbanna to the fish cannery. Measurements from a representative sample of 4 valves are given in Table 6. Total specimens measured of Argopecten eboreus bertiensis include 3 right valves and 4 left valves (USNM 218933, 496224, 362992) from USGS 11999 and 20 right valves and 9 left valves (USNM 362993-362995) from USGS 25758. Tho.se from USGS 11999 are from the Yorktown Formation on the right bank of the Chowan River 0.75 mile (1.2 km) below Mt. Gould Landing, North Carolina. Those from USCiS 25758 are from the Yorktown Forma- tion in a bluff on the west side of the Chowan River approximately 0.5 mile (0.8 km) below Mt. Gould Landing. Measurements from a representative sample of 6 valves are given in Table 7. Argopecten eboreus aff. A. eboreus solarioides (Heilprin), new combination PLATE 9: FIGURES 2, 3; PLATE 10: FIGURES 1-3; PLATE 11: FIGURES 2, 5; PLATE 17: FIGURES 4, 5 Pecten solarioides Heilprin, 1887:99. DESCRIPTION.—Shell Outline: Shell of medium to large size, reaching maximum height of 118 nmi; valves slightly longer than high with a maximum length of I 25 mm. Right valve of low to moderate convexity, with a maximum con- vexity of 22 mm; left valve only slightly more convex than right. Outline of disk approximately equilateral, but slightly extended posteriorly in most specimens; disk flanks very low. Disk gapes moderately broad, reaching 3 mm in larger specimens. Auricles and Outer Ligament: Right anterior auricle with ])lanar to slightly concave surface; dorsal margin slightly dorsal to groove of outer ligament, sharply folded and thickened; folding and thickening of dorsal margin increase away from origin of growth; byssal notch moderately shal- low, with roimdcd to subangular apex; byssal fasciole mod- erately broad and slightly convex; ctenolium of 1 or 2 teeth common in smaller specimens, occasionally 1 tooth visible in specimens uj) to 80 mm in height. Left anterior auricle with moderately concave surface; dorsal margin flat and neatly coincident with trace of outer ligament; free margin slightly rounded with shallow byssal sinus having a rounded apex. Posterior auricles similar in size to anterior; po.sterior slightly higher than anterior; right posterior has planar to slightly convex surface with dorsal margin dorsal to groove of outer ligament and folded more strongly away from NUMBER 61 57 TABLE 4.—Measurements (in mm) of a representative sample of Argopecten eboreus aff. A. eboreus watsonensis. Character USNM 218853 USNM 218854 (D) USNM 218856 (S) USNM 362987 (D) USNM 362988 (D) 22.5 USNM 362989 (S) (D) (S) H 55.0 55.0 77.0 79.0 41.0 27.0 AHL 29.0 28.0 42.0 40.0 20.0 11.5 13.0 PHL 29 30 44 42 21 12 14 L 58.0 58.0 86.0 82.0 41.0 23.5 27.0 ADHD 29 27 37 42 22 12 14 PDHD 31 30 44 42 24 12 14 CON - - 14.5 15.8 - 5.0 5.6 HAA lO.O 11.0 14.0 14.0 8.0 4.5 5.5 HPA 12.0 12.0 17.0 16.0 9.5 6.0 6.5 LAA 18.5 18.0 - 23.0 12.0 7.0 8.0 LPA 18 18 25 24 11 7 8 HL 36.5 36.0 - 47.0 23.0 14.0 16.0 DBN 15 - - - 10 6 _ BN 3.5 - - - 2.0 1.0 _ WP 2.8 3.2 4.6 4.7 1.9 - 1.4 Wl 2.3 1.9 4.0 3.8 1.8 - 0.8 NRIB 18 18 17 17 16 18 18TABLE 5.—Measurements (in mm) ofthe holotype of A. eboreus watsonensis. TABLE 7.—Measurements (in mm) of a representative sample of Argopecten eboreus bertiensis. USNM USNM Character 371139 Character 371139 (D) (D) H 74 HPA 16 AHL 40 LAA 25.5 PHL 42 LPA 25.5 L 82 HL 51 ADHD 33 DBN 22 PDHD 39 BN 3.5 CON 15.3 WP 4.2 HAA 12 Wl 4 NRIB 18 TABLE 6.—Measurements (in mm) of a representative sample of Argopecten eboreus urbannaensis. USNM 362990 (D) USNM 362991 (S) USNM 370829 (D) USNM Character 218862 97 49 57 106 49 50 17.1 18 23 39 34 73 28 II 3.4 2.2 25 66 32 38 70 35 36 13.1 15 13 18 14 32 3.3 1.4 22 (S) H 100 64 AHL 51 30 PHL 53 34 L 104 64 ADHD 50 - PDHD 53 - CON 20.3 9.3 HAA 22 12 HPA 23 15 LAA 35 23 LPA 33 19 HL 68 42 DBN - 16 BN - 7 WP 3.6 2.6 Wl 2.5 1.5 NRIB 21 21USNM USNM USNM USNM USNM USNM Character 218933 362992 362993 362994 362995 496224 (S) (S) (D) (D) (S) (D) H 89 60 57 34 39 81 AHL 46 29 29 16 19 42 PHL 52 35 32 18 20 45 L 98 64 61 34 39 87 ADHD 41 32 27 16 20 38 PDHD 45 30 28 18 20 45 CON 22.3 14.5 16.8 4.3 8.7 11.6 HAA 18.0 12.5 9.0 6.0 8.0 14.0 HPA 16 10 10 8 8 16 LAA 25.0 14.0 13.0 8.5 9.0 24.0 LPA 24 13 12 8 8 21 HL 49.0 27.0 25.0 16.5 17.0 45.0 DBN - - 13.5 7.5 - 22.5 BN - - -0.5 - - 1.5 WR 4.8 2.5 2.5 l.I 1.7 3.3 WG 2.4 1.1 1.7 0.6 0.8 2.3 NRIB 23 23 22 24 24 24 origin of growth; left posterior auricle has slightly concave surface with dorsal margin coincident with trace of outer ligament. Posterior and anterior ligaments about equal in length. Moderate auricular gape both anteriorly and pos- teriorly. Exterior Shell Surface: Number of plicae on valves varies from 19 to 23, with 21 being most common; plicae are relatively sharply defined by steep sides in early growth stages and either remain so throughout or become broadly rounded and lower in later stages; width of plicae on right valves varies from about twice as wide as interspaces to approximately equal width. Right valves of forms with wider, squared plicae occasionally have 1 or 2 weak costae 58 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY on the plicae, but have moderately developed costae in the interspaces, consisting of 1 in the interspaces of the central part of the valve and 1 (or sometimes 2) in the interspaces toward the anterior and posterior margins; the anterior auricles have about 10 moderate to weak costae, and the posterior, 10 to 12; concentric lamellae fair to poorly de- veloped, mostly confined to interspaces. Left valve of forms with squared plicae does not have costae on the plicae, but usually have 1 well-developed median costa in the inter- spaces throughout the valve; the anterior auricles have 7 costae and the posterior 8 or 9; concentric lamellae well developed on interspaces and auricles. Right valves of forms with narrower, rounded plicae have 2 to 4 weakly developed costae on the plicae and none in the interspaces; the anterior auricles have 4 to 6 weak costae and the posterior about 9; concentric lamellae well developed in interspaces and auri- cles and also commonly on plicae. Left valves of forms with rounded plicae occasionally have 1 or 2 weak costae on the plicae and connnonly have 1 and rarely 2 weak costae in the interspaces; anterior and posterior auricles have about 9 costae; concentric lamellae well developed on plicae, interspaces, and auricles. Disk flanks of all valves have well- developed concentric lamellae and 2 to 4 weak costae. Interior Features: Resilial insertion about as long as high, oriented perpendicular to hinge line except for slight pos- terior slant in some left valves; single, weak to moderate auricular denticle both anteriorly and posteriorly. DISCUSSION.—The population sample from the Lee Creek Mine differs from samples of A. eboreus solarioides from the Caloosahatchee Formation of Florida by having a much greater percentage of specimens with rounded rather than squared plicae, and by having a median costa in the interareas on both the right and left valves instead of just the left valve. There is a complex of forms in A. e. solarioides, and this form certainly belongs to the lineage. The specimens from the upper shell bed (units 8 and 9) in the Yorktown Formation in the Lee Creek Mine differ considerably from the specimens of A. eboreus aff. A. eboreus watsonensis, which occur in the lower and middle part of the formation. The specimens from the upper bed are larger in size, ranging to a height of 1 1 8 mm compared to 79 nnn for the largest specimen in the lower beds; the number of plicae is greater, ranging from 19 to 23 with a mean of 21 compared to 16 to 19 for the lower specimens (Figure 1 1), the byssal notch is shallower (Figure 13), and the width of the internal groove is narrower (Figure 15). The shape of the plicae in the sample from the upper bed varies from individuals with broad and raised plicae with a square outline (Plate 11: figure 5), characteristic of A. e. solarioides to those with relatively low and rounded plicae, which become poorly developed in the later portions ofthe valve (Plate 9: figures 2, 3), similar to A. e. senescens, which was described from the Waccamaw Formation in South Carolina. The majority of specimens from the Croatan Formation at Lee Creek were collected in place over the thickness of this unit in the pit. They are grouped as a single population sample with a few float specimens undoubtedly from the same interval. The variation in characteristics ofthe plicae into several groupings could indicate a mixing of assem- blages of slightly different ages or environmental tolerances within the Croatan Formation. However, there does not seem to be any significant amount of time represented in the upper shell bed in the area of collection and there is only a slight change upward in the environment of deposi- tion. The preservation ofthe two extreme kinds is similar, and it is thought that they represent one variable popula- tion. Supporting this interpretation is the fact that samples of A. e. solarioides from the Caloosahatchee Formation in Florida are dominated by specimens with squarish plicae, but there is considerable variation toward rounded plicae in some specimens. It appears that the populations of A. eboreus at the time of deposition of the Caloosahatchee Formation and the upper bed at Lee Creek had a consid- erable range of ornamentation. The two end groups seem to be present in both areas, with a considerable proportion of forms with obsolete plicae in the Lee Creek beds of the (]roatan Formation and the Waccamaw Formation in South (Carolina and fewer in Florida. A careful study of samples from both areas is needed to determine whether there is sufficient difference in population structure to warrant rec- ognition of two subspecies, but samples of this type are not available at the present time. Overall, the Croatan sample from Lee Creek is similar to A. e. solarioides in most char- acteristics, and it is considered to have closest affinities to this group. The Lee Creek specimens have radial costae in the inter- s|>aces, a characteristic of A. e. solarioides. The interspace ornamentation dominantly consists of a single costa, devel- oped over most or all of the disk, and is found on both the left and right valves. In .some specimens the costae are only developed in the lateral interspaces, and in a few specimens the left valve has two costae in the lateral interspaces, a characteristic ofthe specimens found in the Caloosahatchee Formation in Florida. The convexity ofthe left valve in the Lee (^reek specimens is moderate among the A. eboreus group as a whole, with the right valve having a moderately high convexity (Figure 14). The left valve is more convex than the right, but this sample has the second closest simi- larity in convexity between the two valves. The byssal notch is moderately shallow, being less than in A. e. watsonensis and A. e. urbannaensis, but slightly deeper than A. e. bertiensis (Figure 13). SlRATIGRAPHIC AND GEOGRAPHIC RANGE. This grOUp is found in the Croatan Formation in the Lee Creek Mine, and also in the uppermost part of the "Yorktown" at Mt. Gould Landing along the Chowan River, North Carolina. MEASURED MATERIAL.—Total specimens measured of NUMBER 61 59 TABLE 8.—Measurements (in mm) of a representative sample of Argopecten eboreus aff. A. eboreus solarioides. Character USNM 362996 USNM 362997 USNM 362998 (S) (D) (S) (D) (S) (D) H 99.0 100.0 73.0 73.5 40.0 40.0 AHL 51.0 53.0 38.0 39.0 19.5 20.0 PHL 58.0 58.0 41.0 41.5 21.0 20.5 L 109.0 111.0 79.0 80.5 40.5 40.5 ADHD 49 48 39 37 20 21 PDHD 53 52 39 39 21 - CON 20.2 17.1 16.7 13.1 7.2 5.9 HAA 21.0 18.0 15.0 14.5 8.5 7.5 HPA 20.0 22.0 16.0 16.0 9.0 9.5 LAA - - 23.0 24.0 11.0 11.5 LPA 34.0 35.0 23.0 24.0 11.0 11.5 HL - - 46.0 48.0 22.0 22.5 DBN - - 21 - 10 BN - - - 3.0 1.5 WP 4.7 3.9 3.9 3.0 2.8 1.7 Wl 3.4 4.2 2.4 2.5 1.0 1.1 NRIB 21 21 21 21 21 21 Argopecten eboreus aff. A. e. solarioides include 4 right valves and 3 left valves from USGS 25339 and 19 right valves and 7 left valves (USNM 362996-362998) from USGS 25364. Those from USGS 25339 are from spoil piles and those from USGS 25364 from the upper shell bed, both at the Lee Creek Mine. Measurements from a representative sam- ple of 6 valves are given in Table 8. Genus Placopecten Verrill, 1897 Placopecten clintonius clintonius (Say), new combination PLATE 12: FIGURES 2, 4, PLATE 14: FIGURES 1, 2, 5-7; PLATE 15: FIGURES 1, 4 Pecten clintonius Say, 1824:135, pl. 9: Tig. 2. Pecten (Placopecten) clintonius Say.—Dall, 1898:725. Chlamys (Placopecten) clintonius (Say).—Tucker-Rowland, 1938:52-53, pl. l:fig. 11. Chlamys (Placopecten) clintonia (Say).—Gardner, 1944:37, pl. 6; figs. 1, 4.— Mongin, 1959:299, pl. 25: figs. 2a-d. DESCRIPTION.—Shell Outline: Shell large in size, with specimens having heights greater than 100 mm common, and reaching a maximum height of at least 130 mm; length of shell similar to height; left valve more convex than right; left valve moderately convex, reaching 25 mm in larger specimens; right valve low to moderately convex, reaching 14 mm; outline of disk moderately oblique posteriorly; moderate disk gape anteriorly and posteriorly, reaching 3 mm. Auricles and Outer Ligament: Right anterior auricle with a planar to slightly concave surface; dorsal margin nearly coincident with trace of outer ligament and slightly folded; byssal notch very shallow with broad, rounded apex; byssal fasciole poorly developed; no ctenolium observed. Left an- terior auricle with a planar to slightly concave surface; dorsal margin flat and nearly coincident with trace of outer ligament; free margin slightly rounded to straight with very shallow byssal sinus having a rounded apex. Posterior auri- cles similar in size to anterior; surfaces planar to slightly concave; dorsal margins nearly coincident with groove of outer ligament. Posterior and anterior outer ligaments gen- erally about equal in length. Exterior Shell Surface: Both valves with numerous radial costae, numbering about 9 to 10 per centimeter at heights of 100 mm; costae with steeply curved sides and rounded summits; costae narrower than interspaces; interspaces broadly U-shaped; on left valves additional costae during ontogeny added by intercalation; on right valves additional costae added both by intercalation and bifurcation; concen- tric lamellae poorly developed and usually worn; surface of well-preserved valves covered by small elongated pustules, which in .some specimens become suggestive of camptonectes microsculpture. Auricles have 10 to 12 costae with addi- tional ones added by intercalation; concentric lamellae weakly developed. Interior Features: Resilial in.sertion slightly less than 1 V2 times higher than long; orientation ranging from essentially perpendicular to hinge line in most right valves to a gener- allv slightly posterior slope in most left valves; single, mod- erately developed auricular denticle, both anteriorly and posteriorly. DISCUSSION.—Placopecten clintonius, a Miocene species, was considered to be the ancestor of the living scallop, P. magellanicus, by Dall (1898:726) and Gardner (1944:37) because ofthe close morphologic similarity. The absence of any intermediate forms between these two species is prob- ably due to the absence of fossiiiferous cool water deposits of latest Miocene and Pliocene age in the Atlantic Coastal Plain. Beds of this age in the Lee Creek Mine and surround- ing areas of North Carolina and southeastern Virginia are of a considerably warmer character (Gibson, 1967; Hazel, 1971), which would seem to exclude the P. clintonius stock on environmental grounds. P. clintonius is not found south of central North Carolina (the Lee Creek Mine) in the Miocene, and specimens ofthe presumed living descendant, p. magellanicus, have their southern boundary in the Atlan- tic Ocean approximately at Cape Hatteras, North Carolina. Fossiiiferous cool-water deposits of latest Miocene and Pli- ocene age are not found on land in the more northern Atlantic Coastal Plain, but undoubtedly occur on the north- ern continental shelf and there should contain the inter- mediate forms. Dall (1898:726) mentioned the difficulties in separating 60 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY the two species, and used the following criteria: The latter [P. magellanicus] can, however, be at once discriminated from the fossil by the shorter hinge-line, higher auricles, much narrower resiliary pit, and usually, the smaller and less central adductor scar of the recent shell. . . As a rule the radiating threads in the fossils are markedly coarser than those ofthe living species. The ornamentation, as represented by the radial costae, is generally considerably coarser in P clintonius, as men- tioned by Dall (1898:726). Specimens of P. magellanicus have finer costae ranging from 10 to 16 per centimeter at 100 mm height. However, the more southern forms of P. magellanicus have sufficiently coarse costae to overlap with some ofthe more finely costate P. clintonius. It appears that some P. clintonius have coarser ornamentation than any P magellanicus, and many P. magellanicus have finer ornamen- tation than any P. clintonius, but there is overlap in the middle ofthe sculptural range. A population study of the two species was made by comparing P clintonius clintonius from the Lee Creek Mine (from spoil bank material derived from the lower two feet (61 cm) ofthe Yorktown Formation) with living P. magel- lanicus taken on the Atlantic shelf east southeast of Long Island at 67 fathoms (USFC Sta. 2244). The comparison involved those characters used by Dall and subsequent authors as diagnostic between the two species, and some additional ones. As mentioned by Dall (1898:726), Tucker-Rowland (1938:53), and Mongin (1959:299), the resilifer is consid- erably broader in P. clintonius than in P. magellanicus. The gently sloping sides ofthe resilifer in many specimens make it difficult to obtain an accurate measurement. Because of the possibility that the size and shape ofthe resilium is not always closely correlated with the resilifer, measurements were made on both for comparative purposes. The ratio of length to height ofthe resilial insertion differs between the two species, with P. clintonius having a considerably broader resilial insertion (Figure 16), supporting the views of Dall, Tucker-Rowland, and Mongin. The resilifer also varies between the two species, with P. clintonius again having a broader one. While the correlation between height and length of the resilifer is lower than that of the resilial insertion, probably reflecting in large part the difficulty of accurately measuring the resilifer because of the gently sloping sides, this character could be u.sed in species where the resilial insertion is not readily preservable. Valves of P clintonius clintonius from the Lee Creek beds are posteriorly oblique in shape, whereas valves of P. magel- lanicus are very slightly, if at all, oblique. This difference is noted by comparing the anterior and posterior half-lengths ofthe valves ofthe two species. As indicated in Figure 17, P clintonius clintonius has a considerably larger posterior half-length, whereas P. magellanicus has nearly equal pos- terior and anterior half-lengths. Other specimens of P. clintonius clintonius from various localities in Virginia do not exhibit as marked an obliquity of the valves. Several of the other characters mentioned by Dall and others as distinguishing the two species were also studied. Dall (1898:726) and Tucker-Rowland (1938:53) mention that a distinguishing character of P. magellanicus is the shorter hinge line as compared to P. clintonius clintonius. In the populations studied, no difference in length of the hinge line can be seen between the two species (Figure 18). If anything, the larger specimens of P. magellanicus have a generally longer hinge line rather than shorter. Another differentiating character mentioned by Dall (1898:726) is that the auricles are higher in P. magellanicus. No significant difference was noted in this study (Figure 19). Nevertheless the general trend is toward a slightly higher posterior auricle in P. clintonius clintonius rather than otherwise. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—This spe- cies occurs in abundance in the lower 2 to 3 feet (0.6 to 0.9 m) of the Yorktown Formation in the Lee Creek Mine. Mansfield (1929b:l) used this species to name his lowest zone ofthe Yorktown Formation in Virginia, calling it zone 1 or Pecten clintonius zone. P. clintonius clintonius is re- stricted to this zone, and is an excellent guide fossil in North Carolina and Virginia. Another subspecies, P. clintonius rappahannockensis (Mansfield) is found in the beds immedi- ately underlying Mansfield's zone 1 of the "Yorktown" in North Carolina, and a slight distance below in several local- ities in V^irginia. These beds were placed in the "Virginia St. Marys" beds by Mansfield (1944) but were included in the Yorktown Formation by Gibson (1971). MEASURED MATERIAL.—Total specimens measured of Placopecten clintonius clintonius include 35 right valves and 27 left valves from USGS 25338, (USNM 362999-36300), and 4 right valves and 7 left valves from USGS 25339 (USNM 363001-363003). Both collections are from spoil banks ofthe Yorktown Formation, Lee Creek Mine, North Carolina, and include a total population sample of 39 right valves and 34 left valves. Measurements of a representative sample of 8 valves are given in Table 9. Placopecten clintonius rappahannockensis (Mansfield), new combination PLATE 18 Pecten (Chlamys) clintonius rappahannockensis Mansfield, 1936:186-187, pl. 22: figs. 1-3. Chlamys (Placopecten) clintonius rappahannockensis (Mansfield).—Tucker- Rowland, 1938:53-54, pl. 3: fig. 6, pl. 4: fig. 1. DESCRIPTION.—Shell Outline: Shell large in size, reach- ing heights of 1 30 mm; length of shell is similar to or slightly greater than the height; left valve more convex than right; left valve moderately convex, reaching 19 mm in larger specimens; right valve of low convexity, reaching 13 mm in NUMBER 61 61 9r— z 6 o A A A U. 4 O A P. clintonius clintonius o P. clintonius rappahannockensis • P. magellanicus 4 5 6 HEIGHT OF RESILIAL INSERTION FIGURE 16.—Bivariate scatter diagram showing the differences in the size ofthe resilial insertion among samples of subspecies of Placopecten clintonius (Yorktown Formation, North Carolina) and P. magellanicus (Holocene, New England shelf). = oo° - or>.^ \ «A AA - 0# • AA A O* o«« - o ''''.\ A P. clintonius rappahannockensis O P. magellanicus P. afl. P. magellanicus t 1 1 1 1 1 1 1 1 POSTERIOR HALF LENGTH FIGURE 17.—Bivariate scatter diagram showing the difference in the shape ofthe valve among various subgroupings of Placopecten. TABLE 9.—Measurements (in mm) of a representative sample of Placopecten clintonius clintonius. Character USNM 362999 USNM 363000 USNM 363001 (S) (D) USNM 363002 (S) USNM 363003 (S) (D) (S) (D) (D) H 68.0 70.0 112.0 109.0 90.0 89.0 46.5 48.0 AHL 33 33 51 52 41 38 21 22 PHL 39 38 65 60 49 47 25 26 L 72.0 71.0 116.0 112.0 87.5 85.0 46.0 48.5 ADHD 32 33 51 44 39 37 20 22 PDHD 37 39 53 55 43 45 22 24 CON 10.2 7.0 21.0 14.2 12.8 9.1 6.0 5.1 HAA 11.5 11.0 17.0 16.0 15.0 14.5 9.5 8.0 HPA 10.0 12.0 14.0 17.0 15.0 16.0 8.5 9.5 LAA 13.0 13.2 22.0 23.5 16.0 - 10.0 9.0 LPA 14.0 13.5 21.3 19.0 15.0 15.5 9.5 10.0 HL 26.0 26.5 42.0 42.0 30.0 33.0 18.0 19.5 DBN 14.7 - 24.4 - 19.0 - 10.2 BN -1.5 - -0.9 - - -1.2 HR 5.01 5.62 9.17 9.94 6.68 7.02 2.60 - LR 4.43 4.94 8.10 8.50 6.71 6.89 2.85 - HRI 4.47 4.45 8.39 8.34 6.36 6.35 2.42 2.46 LRI 3.20 3.30 6.74 6.47 4.29 4.32 1.89 2.0162 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY larger specimens; outline of disk equilateral with essentially identical anterior and posterior half-diameters; disk gape moderately broad anteriorly and posteriorly. Auricles and Outer Ligament: Right anterior auricle with a planar to slightly concave surface; dorsal margin nearly coincident with trace of outer ligament and slightly folded; byssal notch very shallow with broadly rounded apex; byssal fasciole poorly developed; no ctenolium observed. Left an- terior auricle with a planar to slightly convex surface; dorsal margin nearly coincident with trace of outer ligament and slightly folded; free margin slightly rounded to straight with a very shallow byssal sinus having a rounded apex. Posterior auricles similar in height to anterior and have essentially planar surfaces. Anterior outer ligament longer than pos- terior. Moderate auricular gape. Exterior Shell Surface: Both valves with numerous radial costae, numbering about 11 to 15 per centimeter at height of 100 nnn; costae low, with steep sides and ftat, broad summits; costae equal in width to slightly narrower than interspace; interspaces broadly U-shaped; on left valves additional costae during ontogeny added by intercalation and bifurcation; on right valves additional costae added largely by bifurcation; concentric lamellae poorly developed and usually worn. Auricles have 5 to 10 weakly developed costae; concentric lamellae poorly developed. Interior Features: Resilial insertion slightly higher than long; orientation generally with a slight posterior slant in both valves; single, moderately developed auricular denticle both anteriorly and posteriorly. DISCUSSION.—This subspecies differs from P. clintonius clintonius in characteristics ofthe radial ornamentation. The costae in P. clintonius rappahannockensis are more numer- ous, numbering from 11 to 15 per centimeter, are lower and wider with broadly rounded to flattened summits, and the interspaces are relatively narrow and shallow. In com- parison, the costae on P clintonius clintonius range from approximately 5 to 10 per centimeter, are higher and narrower with subangular to rounded summits, and the interspaces are relatively deep and broad. As mentioned by Mansfield (1936:187), the hinge line of P clintonius rappahannockensis is longer, although this is mostly characteristic of immature specimens (Figure 18). The height of the auricles in the two subspecies is similar (Figure 19), but P. clintonius rappahannockensis has a longer anterior auricle in relation to shell length (Figure 20) and a longer anterior auricle than posterior. P. clintonius clintonius has auricles approximately equal in length. The valves of P. clintonius rappahannockensis are es.sen- tially equilateral, and differ from the Lee Creek .sample of P clintonius clintonius in which the valves are sharply not equilateral (Figure 17). Other population samples of P. clintonius clintonius from Virginia, however, more closely approach being equilateral. The resilial insertion has a relatively great length in both subspecies of P. clintonius compared to P. magellanicus (Figure 16). Emmons (1858:280) named Pecten princepoides from the Miocene strata along the Meherrin River near Murfrees- boro, North Carolina. From the type figure and subsequent collecting in the type area, it is clear that this taxon belongs to Placopecten clintonius as Dall (1898:726) noted. Of which subspecies it is a synonym is a more difficult problem as both subspecies are found in this area, in places within a foot of each other sttatigraphically. The type figure (Em- mons, 1858, fig. 198) seems to be of a finely striate form like P. clintonius rappahannockensis, but the description (Em- mons, 1858:280) mentions that the radiating striae are "coarse," which would seem better to fit P clintonius clin- tonius. The description also mentions that the ears are unequal, which would be indicative of P. clintonius rappa- hannockensis, as would be the size which has a length of 5'/i inches (13.3 cm). A final determination will have to be made from whatever type material can be found. STRATIGRAPHIC AND GEOGRAPHICAL RANGE.—This subspecies occurs in the upper part of the "Virginia St. Marys" beds of Mansfield (1944:6), also called zone 2 or (Crassatellites meridionalis zone. These strata were reassigned by Gibson (1971) to the lowermost part of the Yorktown Formation as the initial part of the Yorktown depositional cycle in the Virginia-northern North Carolina area. The subspecies is found in beds of this age along the Rappahan- nock and James rivers in Virginia and the Meherrin River in northernmost North Carolina, and occurs immediately or closely below the strata of Mansfield's zone 1 of the "Yorktown," the P. clintonius clintonius zone. MEASURED MATERIAL.—Total specimens measured of Placopecten clintonius rappahannockensis include 5 right valves and 4 left valves (USNM 218878, 218879, 363004) from USGS 3924, one right valve from USGS 8179, and 5 right valves and 4 left valves (USNM 363005-363007) from USCiS 25747. All are from the lowermost part of the Yorktown Formation: USGS 3924 from bluff at "Jones Point" on the Rappahannock River about 21 km north of Urbana, V^irginia; USGS 8179 from the beach about 0.8 km downstream from "Jones Point"; USGS 25747 from bluff on Meherrin River 4.8 km above Highway 158 bridge. Meastnements from a representative sample of 9 valves are given in Table 10. Placopecten sp. aff. P. magellanicus (Gmelin), new combination PLAIT. 16: FIGURE 1, PLATE 17: FIGURE 3 Ostrea magellanica Gmelin, 1791:3317. DESCRipnoN.—Shell Outline: Shell medium in size, height of 88 mm; length slightly longer than height; right valve with low convexity of 9 mm; outline of disk essentially equilateral with a slightly longer posterior half-length. 60 T»m o o 50 • • A • O • _A A •^ A AAA A A ^ 40 n •. A A ^ • A A A A AA AAA AA A A A UJ ° A AA A I o • ^A Ays u. -^o o A " •• • I o 0 0 • AA •t • ^- o •£•• A P. clintoniu s clintonius z ^ O P. clintoniu s rappahann Dckensis _1 20 \ • •• ..« A -> tfi • • •• • P. D P. magella aff. P. magellanicus 10 • 1 1 1 1 1 1 1 1 1 1 1 1 0 30 40 SO 60 70 80 90 100 llO 120 130 140 FIGURE 18.—Bivariate scatter diagram showing the similarity in the length of the hinge line among various subgroupings of Placopecten. A A y^AAAAA A AA A A ••£# A • I. • • • A • O AO go ••& • • • •• ^ P. clintonius clintonius o p. clintonius rappahannockensis • P. magellanicus D P. aff. P. magellanicus 20 30^ 40 50 bO 70 80 LINEAR HEIGHT "90 Too no IM FIGURE 19.—Bivariate scatter diagram showing variation in the height of the posterior auricle in various subgroupings of Placopecten. A ▲ ▲ AAA y 15 A P. clintonius clintonius Q P. clintonius rappahannocken J L 50 60 J L 80 90 100 110 130 140 FIGURE 20.—Bivariate scatter diagram showing the greater length of the anterior auricle in a sample of Placopecten clintonius rappahannockensis (basal Yorktown Formation, Virginia and North Carolina) compared to a sample of P. clintonius clintonius (Yorktown Formation, North Carolina). 64 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TABLE 10.—Measurements (in mm) of a representative sample of Placopecten clintonius rappahannockensis. Character USNM 218878 USNM 218879 USNM 363004 (D) USNM 363005 (D) USNM 363006 (S) USNM 363007 (S) (D) (S) (D) (S) (D) H 66 67 112 107 76 55 42 130 127 AHL 34 33 58 57 37 27 21 67 69 PHL 33 33 59 58 37 29 20 69 69 L 67 66 117 115 74 56 41 136 138 ADHD 30 32 - 54 36 - 21 55 50 PDHD 32 32 53 52 35 28 21 58 54 CON 8.5 7.1 17.9 12.1 8.5 6.0 5.1 17.4 11.5 HAA 12.0 12.0 17.0 17.5 13.0 11.0 9.5 18.0 16.5 HPA 11.0 12.0 15.0 18.5 12.0 10.0 7.5 16.0 17.0 LAA - - 25.0 27.0 19.0 14.5 - 32.0 32.0 LPA - 13.0 23.5 21.0 13.5 11.5 9.0 27.0 HL - 48.5 48.0 32.5 26.0 - 59.0 DBN - 18 - 28 20 14 - - 34 BN - - -1.0 -1.0 0.5 - - -2.0 HR 4.1 5.0 7.2 8.6 6.5 4.0 2.5 - - LR 5.7 4.3 10.3 9.0 6.8 3.6 3.2 - - HRI - 5.0 7.2 - 5.9 3.0 1.8 9.7 10.4 LRI - 3.7 8.3 - 5.9 2.6 1.8 8.5 9.0 Auricles and Outer Ligament: Right anterior auricle with a planar surface; dorsal margin nearly coincident with trace of outer ligament and slightly folded; byssal notch very shallow with broadly rounded apex; byssal fasciole poorly developed; no ctenolium observed. Right posterior auricle with planar surface; dorsal margin nearly coincident with trace of outer ligament and folded; free margin slightly curved. Posterior auricle similar in height to anterior. An- terior outer ligament longer than posterior. Exterior Shell Surface: Right valve with numerous radial costae, about 16 to 18 per centimeter; costae are low and broad, with gently sloping sides; costae wider than inter- spaces; interspaces shallow and narrow; concentric lamellae poorly developed. Auricles with about 10 weakly developed costae; concentric lamellae moderately developed. Interior Features: Resilial in.sertion about as long as high, oriented perpendicular to hinge line; single, moderately developed auricular denticle both anteriorly and poste- riorly. DLSCUSSION.—Placopecten clintonius from the Yorktown Formation ofthe Atlantic (>oastal Plain has been considered the ancestral form ofthe living/*. magellanicus ofthe North Atlantic Ocean (Dall, 1898:726). However, no forms tran- sitional in morphology or age between the two species have been found in the younger (Cenozoic strata of the Atlantic (loastal Plain. A single right valve found in the Lee Oeek Mine appears to be an intermediate form between the two species in that lineage. The specimen was collected by Jack McLellan from spoil banks in the Lee Creek Mine. It was determined to be from the Yorktown P^ormation on the basis ofthe type of .sediment adhering to small cracks in the shell; but the crucial information as to the exact strati- graphic occurrence in the Yorktown Formation is lacking. The cementation of part of an echinoid test onto the shell is a strong indication that the specimen came from unit 2 of Gibson (1967). From a phylogenetic viewpoint, the spec- imen should come from .somewhere above the basal beds of the Yorktown, which contain the supposed ancestor, typical P. clintonius, and if it is from unit 2 this would be true. Because there is only the one specimen, and particularly because the precise stratigraphic position is uncertain, the specimen will not be placed more definitely taxonomically until additional valves with stratigraphic information are found. "Fhe specimen has closer proximity to P. magellanicus morphologically, although it is presumably very close to P. clintonius stratigraphically. The shape ofthe single right valve of Placopecten sp. aff. P. magellanicus is similar to that ofthe modern P. magellan- icus in being equilateral with a fairly equal anterior and posterior half-length (Figure 17). This contrasts with the moderately oblique shape of the disk in a population of P. clintonius clintonius from the Lee Creek Mine. The ornamentation on the disk of Placopecten sp. aff. P. magellanicus consists of very fine radial costae. The strength of the costae is considerably less than that found in P. clintonius, especially in the population from the mine, which has moderate to coarse radial ornamentation. The single specimen from the mine has costae that fall about midway in the range of variability of P. magellanicus, not being as sharply defined as in the coarser forms, but not being so flat as to be essentially smooth as in the more finely orna- mented examples. NUMBER 61 65 The auricles of Placopecten sp. aff P. magellanicus are different from those of both P clintonius and P. magellani- cus, although they are more similar to the latter. In com- paiison to P. clintonius clintonius, the auricles in the single specimen of Placopecten sp. aff. P. magellanicus have consid- erably finer costae. The posterior auricle has an essentially straight free margin perpendicular to hinge line, whereas in P. clintonius this margin has a strong posterior slant away from the hinge line. In the specimen of Placopecten sp. aff. P. magellanicus the anterior end of the anterior outer liga- ment is about the same distance from the origin of growth as is the innermost part ofthe byssal notch. In P. clintonius the bysall notch is more anterior than the anteriormost end of the ligament. The hinge line of Placopecten sp. aff. P. magellanicus is longer than most specimens of P. clintonius clintonius (Figure 18). Although there are close similarities in most characteristics of the auricles between the popula- tion of P. magellanicus and the specimen of Placopecten sp. aff. p. magellanicus (Figure 19), the latter has longer auricles than most specimens of P. magellanicus. (See Plate 16: figures 1 and 2 where the similar-sized valve of P. magellan- icus has considerably shorter auricles.) The resilial insertion of Placopecten sp. aff. P. magellanicus is relatively long in relation to its height, being similar to the shape of P. clintonius but significantly wider than that of P. magellanicus. No absolute measurements are given for the resilial insertion, as it is fractured and separated. Placopecten sp. aff. P. magellanicus is close to P magellan- icus in many characteristics, and appears to be well along in the phylogenetic sequence from P. clintonius clintonius to that species. Unfortunately, without knowing how far above the basal Yorktown beds (containing P. clintonius clintonius) the specimen occurred, the rapidity of this transition cannot be determined. As mentioned, the nature of the small amount of sediment in crevices on the specimen and the echinoid fragment cemented to the shell suggest that the specimen came from the upper lower part ofthe Yorktown or lower middle part ofthe Yorktown (upper part of unit 2 to lower part of unit 5, most probably unit 2), indicating a rapid phylogenetic change. The possibility that the single specimen is an extreme variant within the population of P. TABLE 11.—Measurements (in mm) of the specimen of Placopecten sp. aff. P. magellanicus. USNM USNM Character 218873 Character 218873 (D) (D) H 88 HPA 12.0 AHL 47 LAA 21.0 PHL 46.5 LPA 18.5 L 93.5 HL 39.5 ADHD 36 DBN 21.0 PDHD 41 BN 0 CON 9.1 WP - HAA 12.5 Wl -clintonius clintonius cannot be dismissed entirely, but as little variation toward this form is observed in the hundreds of valves examined from the Lee Creek Mine and other sec- tions in the Atlantic Coastal Plain, it seems unlikely. MEASURED MATERIAL.—The measurements ofthe spec- imen of Placopecten sp. aff. P magellanicus, USNM 218873, from USGS 25743; spoil piles, Lee Creek Mine, North Carolina, are given in Table 11. Genus Chlamys Roding, 1798 Chlamys decemnaria (Conrad) PLATE 15: FIGURES 2, 3, 5-7, PLATE 16: FIGURES 3-5; PLATES 19, 20 Pecten decemnarius Conrad, 1834:151; 1840:49, pl. 24: fig. 2. Pecten virginianus Conrad, 1840:46, pl. 21: fig. 10. Pecten dispalatus Conrad, 1845:74, pl. 42: fig. 3. Pecten (Placopecten) virginianus Conrad.—Dall, 1898:727. Pecten ((Chlamys) decemnarius Conrad.—Dall, 1898:741. Chlamys (Placopecten) virginianum (Conrad).—Tucker, 1934:617. (Chlamys (Chlamys) decemnarius (Conrad).—Rowland, 1936b:1009, pl. 8: figs. 5-6. Chlamys (Placopecten) virginianus (Conrad).—Tucker-Rowland, 1938:55-56, pl. 4: fig. 22, pl. 5: fig. 14. Chlamys decemnaria (Conrad).—Gardner, 1944:31-32, pl. 5: figs. 1-2, 6.7. Chlamys (Placopecten) virginiana (Conrad).—Gardner, 1944:38-39, pl. 4: fig. 3. DESCRIPTION.—Shell Outline: Shell of medium size, at- taining height of 78 mm; both valves of low to moderate convexity, with left valve of equal to slightly greater con- vexity than right. Outline of disk equilateral; height of valve similar to length; disk fianks low. Narrow disk gape anter- iorly, none posteriorly. Auricles and Outer Ligament: Right anterior auricle with planar surface; dorsal margin slightly dorsal to groove of outer ligament and strongly folded; byssal notch moderately deep with broadly to moderately rounded apex; byssal fasciole moderately broad and planar; ctenolium with 3 to 4 teeth well developed throughout. Left anterior auricle with planar surface; dorsal margin fiat and coincident with trace of outer ligament; free margin straight and essentially 90 degrees to hinge line. Posterior auricles much smaller than anterior; surfaces planar; free margin straight, slanted posteriorly. Anterior outer ligament almost twice as long as posterior. Exterior Shell Surface: Radial ornamentation on right valve less strongly developed than on left valve; radial ornamentation varies greatly in development; disk orna- mentation ranges from very low, broad costae separated by narrow grooves, numbering about 16 to 18 costae per centimeter, to strongly developed plicae, numbering 10 to 12 per disk; costae increase in number by bifurcation, may be unequal strength. Right valves have plicae broader than interspaces; plicae vary in development from low with broadly rounded sides to low with almost vertical sides; 66 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY interspaces contain 3 costae. Left valves have narrow plicae with interspaces 3 to 4 times as wide; plicae vary in shape from very low and rounded to moderately high and sharply defined; costae not present on the plicae; as many as 12 costae in the interspaces. Concentric lamellae developed only on strongly plicate right valves, but strongly developed on all plicate left valves. Right anterior auricles have 6 to 8 costae, low, rounded, and broad with narrow grooves; right posterior have 6 to 20 low and narrow costae, more weakly developed than on anterior; auricles on left valve have 10 to 20 costae, with generally more on the anterior than posterior; there is no increase in strength of the costae on the auricles with increasing strength ofthe costae and plicae on the disk. Concentric lamellae poorly to moderately de- veloped on auricles of right valves, more strongly developed on auricles of left valves. Interior Features: Resilial insertion about 11/2 times as high as long, oriented perpendicular to hinge line; single, weakly developed auricular denticle both anteriorly and posteriorly. DISCUSSION.—Samples of more than 300 specimens of Pecten decemnarius and Pecten virginianus from the Lee C>reek Mine show the complete intergradation of these previously separated species. These two forms are only moderately common in most localities and, although people have noted the co-occurrence and similarities between them, heretofore they have not been considered as belong- ing to a single variable .species. For example, Mansfield (1936:178) noted that ""Pecten decemnarius Conrad and Pec- ten virginianus Conrad are closely related and usually occur together." In the same paper, Mansfield considered both species questionably to have evolved from Placopecten clin- tonius. A population sample was composed of specimens occurring together on the spoil piles in a similar matrix, coming from the indurated silty sand in the lower part of unit 5. (Chlamys decemnaria and rotten specimens of Turri- tella are about the only fossils present. The presence of articulated specimens in the Lee Creek material shows the variation in the strength of the orna- mentation on the two valves of an individual specimen. Regardless of whether the general development of the ornamentation is strong or weak, the right valve has consid- erably weaker development than the left (Plate 15: figures 2, 3, 6, 7; Plate 16: figures 4, 5). Within the large sample, it is possible to demonstrate an intergrading sequence of ornamentation from fine radial costae to coarse plications with coarse concentric lamellae (Plates 1 9, 20). On the right valves (Plate 19) the ornamentation exhibits wide variation, ranging from fine costae (figure 1) to moderate costae on a slightly undulating surface marked by more conspicuous grooves (figure 2), to moderately coarse costae with the undulations and grooves developing into plicae (figures 3- 5), and then to increasingly better developed plicae with coarser costae (figures 6-13). Coarse concentric lamellae occur commonly in the coarser stages of the plicae (figures 10, 13). A similar increase in the development ofthe plicae and other ornamentation is observable on the left valves (Plate 20). Because the costae and/or plicae are coarser on the left valve than on the right, specimens with a finely costate right valve usually have moderately strongly sculp- tured left valves. Therefore, finely sculptured left valves are not common, but do occur (figure 2). The costae in- crease in coarseness (figure 3), and then valves occur with rai.sed areas or plicae composed of two or three costae formed by bifurcation of an earlier raised single one (figure 5). The plicae become stronger, and along with them the intervening costae (figures 6, 7), with the development commonly of coarse concentric lamellae as on the right valve (figure 8). The extreme stage consists of three to five strong plicae along with a number of weaker plicae in varying stages of development, reflecting the coarsening of the costae between the plicae, commonly those formed by bifurcation from the original strong one (figure 9). In this variation, i.e., Pecten dispalatus Conrad, both the stronger and weaker plicae have coarse concentric lamellae. Although the ornamentation is intergradational between the two nominal species, a check of other possibly significant morphological characters was made to see if they also showed overlap. Specimens were divided into three groups on the basis of the strength of the ornamentation. These groups included the following three forms: (1) those with fine to moderate costae, without plicae, i.e., typical Pecten virginianus; (2) those with moderately developed costae and the incipient to moderate appearance of plicae, i.e., Pecten decemnarius; and (3) those forms with well-developed plicae and moderate to coarse costae along with concentric lamel- lae, i.e., typical Pecten decemnarius. A comparison among the three morphologic groups was made on the basis of external shell morphology, including features ofthe disk, auricles, and byssal notch. None ofthe comparisons indicates any difference among the three groups. Whether the characters used have a very high correlation (Figure 21) or only a moderate correlation (Figure 22), the three groups show no significant differ- ences. Characteristics of the byssal notch, which have proven important in other species and genera, show that although the relatively deep byssal notch is a variable char- acter within each group, it is similar among the three groups (Figure 22). The considerably greater length of the anterior auricle in comparison to the posterior auricle also is consist- ent among the three groups (Figure 21). Because of the indurated matrix on the specimens, only external characters were u.sed. 1 he absence of significant differences in any ofthe stud- ied characters among the three groups reinforces the con- clusion that the range in ornamentation is just a variable characteristic of a single species. This wide range of orna- mentation is greater than in most species of pectens. As NUMBER 61 67 I6l— O OO ^ ^ "o cr o o^ ■■ A O O ■ ■ QB ■ C . decemnaria O smooth forms ■ intermediate for A coarse forms 12 14 16 LENGTH OF ANTERIOR AURICLE FIGURE 21.—Bivariate scatter diagram showing similarity in length of the auricles in different forms of Chlamys decemnaria from a sample in the Yorktown Formation in the Lee Creek Mine. C. decemnaria O smooth forms ■ intermediate forms A coarse forms ^ ■ o AOS 40 50 LENGTH OF DISK FIGURE 22.—Bivariate scatter diagram showing similarity in depth ofthe byssal notch in different forms of Chlamys decemnaria from a sample in the Yorktown Formation in the Lee Creek Mine. 68 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY both the finer and more coarsely ornamented forms are generally found in most localities, it appears that the wide range of ornamentation is a common genetic characteristic throughout the time range of the species. It also appears that as far as can be determined no phylogenetic or geo- graphic trends towaid finer or coarser plicae are present in the North Carolina-Virginia area. A wide variety of species have been placed in Chlamys, including the more recent placements of ""Pecten" decemnar- ius. Although the ornament pattern in ""Pecten' decemnarius is within the range of the type-species of (Chlamys and other closely related species, it differs in not having the elongated shape of the disk characteristic of Chlamys islandicus, the type-species. Until a thorough reclassification ofthe Pectin- idae is available, ""Pecten' decemnarius is placed in the genus (Chlamys. ""Pecten" virginianus generally has been placed in the then subgenus Placopecten (Dall, 1898:727; Tucker- Rowland, 1934:617; 1938:55; Gardner, 1944:38), although these workers noted that ""Pecten' virginianus and Placopec- ten clintonius differ by the former having a much deeper byssal notch and a strongly developed ctenolium. These two species were placed in the then subgenus Placopecten because of a general similarity in the shape and convexity ofthe two valves and their fine radial ornamentation. Dif- ferences in the byssal notch, however, and the intergrada- tion with coarser radial ornamentation including plicae in the "P." virginianus and "P. " decemnarius suite, make this placement questionable. The transition between "P." virgi- nianus (usually placed in the subgenus Placopecten) and "P." decemnarius (usually placed in the subgenus Chlamys) does indicate that there may be a close relationship between the two groups, here regarded as genera. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—This spe- cies occurs in units 3 to 5 of Gibson (1967) in the Yorktown Formation at the Lee Creek Mine and is fairly common in this interval. The species previously has been reported in the Yorktown Formation from the Pamunkey River in Virginia southward to Greenville, North Carolina (Gardner, 1944:32). Dall (1898:741) also reported it from the Ashley River phosphate rock in South Carolina, but the specimen is only a small fragment of an external mold and cannot be placed with certainty. This species usually occurs strati- graphically closely above the range of Placopecten clintonius, which is the common guide species to the lower part of zone 1 of Mansfield (1944). (Chlamys decemnaria is recorded by Mansfield (1936:178) in the lower part of his zone 2, but he considered its occurrence doubtful in zone 1. It is possi- ble that some of the occurrences of this species, such as the lower part ofthe range in the Lee Creek Mine, should be placed in the upper part of zone 1 ofthe Yorktown, but the sparsity of the as.sociated fauna limits this determination. As of this time, therefore, the known range of the .species is the lower part of Mansfield's zone 2 of the Yorktown Formation. MEASURED MATERIAL.—Total specimens measured of TABLE 12.—Measurements (in mm) of a representative sample of smooth forms of Chlamys decemnaria. USNM USNM USNM USNM Character 363008 363009 363010 363011 (D) (D) (D) (D) H 23.5 73.0 38.0 58.5 AHL 12 39 18 31 PHL 10.0 38.5 17.5 28.5 L 22.0 77.5 35.5 59.5 ADHD 12 35 20 30 PDHD 12 34 20 32 CON 3.6 10.6 4.6 9.2 HAA 4.5 11.0 6.5 10.0 HPA 5.5 11.5 7.0 11.0 LAA 8 20 10 17 LPA 3.5 13.0 5.5 11.0 HL 11.5 33.0 15.5 28.0 DBN 5.0 15.0 7.0 12.5 BN 3.0 5.0 3.0 4.5 TABLE 13.—Measurements (in mm) of a representative sample of intermediate forms of Chlamys decemnaria. USNM USNM USNM Character 363012 363013 363014 (D) (D) (D) H 50 38 23 AHL 26 18 11 PHL 26.0 17.5 11.0 L 52.0 35.5 22.0 ADHD 24 20 11 PDHD 26 20 12 CON 5.9 5.3 3.3 HAA 8.5 7.0 3.8 HPA 8 8 5 LAA 14.0 9.0 6.5 LPA 9.0 5.0 3.5 HL 23 14 10 DBN 11.0 7.0 4.4 BN 3.0 2.0 2.1 TABLE 14.—Measurements (in mm) of a representative sample of coarse forms of ( Ihlamys decemnaria. USNM USNM USNM Character 218890 363015 363016 (I)) (D) (D) H 58.0 41.5 28.0 AHL 28 22 14 PHL 27.5 19.0 12.5 L 55.5 41.0 26.5 ADHD 28 20 15 PDHD 28 20 15 CON 8.3 7.0 4.6 HAA 10.5 7.5 5.5 HPA 11.5 9.0 6.0 LAA 15 13 10 LPA 10.0 7.5 5.5 HL 25.0 20.5 15.5 DBN 11 9 6 BN 4 4 4NUMBER 61 69 Chlamys decemnaria include 88 right valves (USNM 218890, 363008-363016) from USGS 25338, spoil banks of the Yorktown Formation, Lee Creek Mine, North Carolina. Measurements from representative samples showing radial ornamentation relatively smooth (4 valves), intermediate (3 valves), and coarse (3 valves) are given in Tables 12-14. Genus Chesapecten Ward and Blackwelder, 1975 Chesapecten jeffersonius jeffersonius (Say) PLATE 21: FIGURES 1-6, PLATE 22: FIGURES 4-6, PLATE 23: FIGURES 4, 5 Pecten Jeffersonius Say, 1824:133, pl. 9: fig. 1. Pecten (Chlamys) jeffersonius Say.—Mansfield, 1936:174-175, 178-179, 184-185. (Chlamys (Lyropecten) jeffersonius (Say).—Tucker-Rowland, 1938:19-20, pl. 1: figs. 3-4, pl. 5: figs. 19-20. Chlamys (Lyropecten) jeffersonia (Say).—Gardner, 1944:32-34, pl. 4: fig. 2. Chlamys jeffersonia (Say).—Mongin, 1959:307-308, pl. 27: fig. 3. Chesapecten jeffersonius (Say).—Ward and Blackwelder, 1975:13-15, pl. 1, pl. 2: figs. 1-3, pl. 5: figs. 3-7, pl. 7: figs. 3, 10. DESCRIPTION.—Shell Outline: Shell large, attaining height of 152 mm; both valves of moderate convexity, with left valve more convex than right; convexity reaching 37 mm in left valves and 32 mm in right. Outline of disk almost equilateral with slight posterior obliqueness; shells slightly longer than high, more pronounced in larger specimens. Moderate disk gape anteriorly and posteriorly, reaching 5 mm in larger specimens. Auricles and Outer Ligament: Right anterior auricle with planar surface; dorsal margin slightly dorsal to groove of outer ligament and slightly folded; byssal notch shallow with broad, subangular apex; byssal fasciole poorly developed; ctenolium with 3 or 4 teeth well developed in specimens up to 80 mm height, absent in larger individuals. Left anterior auricle with concave surface; dorsal margin flat and coinci- dent with trace of outer ligament; free margin slightly curved with a broad, shallow byssal sinus. Posterior auricles similar in size to anterior, except posterior are slightly higher; surfaces planar to slightly concave; free margins nearly straight and perpendicular to hinge line. Anterior and posterior outer ligaments about equal in length. Exterior Shell Surface: Valves with 8 to 12 large plicae; in early stages of growth plicae have vertical sides and are sharply defined from interspaces; in later stages plicae be- come more rounded and sides have about a 45 degree slope; plicae slightly wider than interspaces. Radial costae strongly developed on shell with a scabrous appearance where crossed by concentric lamellae; costae number as many as 20 on the plicae, with up to 5 on the sides ofthe plicae, and as many as 18 in the interspaces; costae of varying strengths but generally uniform. Concentric lamellae well developed over the valves. Auricles have about 25 costae of about equal strength with well-developed concentric lamellae giv- ing a scabrous appearance. Disk flanks steep and covered with numerous costae. Inferior Features: Resilial insertion about twice as high as long; oriented with a slight to moderate posterior slope; single auricular denticle of weak to moderate development both anteriorly and posteriorly. DISCUSSION.—This species is one of the most abundant mollusks in the lower part of the Yorktown Formation in the Lee Creek Mine. The Chesapecten group exhibits a great amount of morphologic change during its phylogeny, mak- ing it valuable for biostratigraphy, and C. jeffersonius has several forms that are distinctive for the lower and middle parts ofthe Yorktown Formation. The morphologic trends within the (C. jeffersonius lineage are being studied by the author from carefully sampled sections of the Yorktown Formation in Virginia, particularly along the James River, and in North Carolina, where population samples collected in 1 foot (0.3 m) vertical intervals are available. Because of the phylogenetic changes in this lineage and the lack of detailed stratigraphic sampling information for the Lee Creek specimens, the three common taxa ofthe C. jefferson- ius species group are compared only in general subspecific or specific terms. Detailed subspecific phylogenetic trends between populations will be discernible in the precisely collected sections. Although both valves are convex, the left valve is more convex than the right with a ratio of convexity of 0.77 to 0.83 between the valves in mature specimens and an even greater left convexity in younger individuals with ratios as low as 0.63. The strong developed plicae are broadly rounded in the stratigraphically earlier forms of this sub- species, but become more squared with flattened tops and nearly vertical sides in the higher parts of zone 1 where C. jeffersonius septenarius develops from it. In the population sample of (C. jeffersonius jeffersonius from the pit, the number of plicae varies from 8 to 12 (Figure 23) with a mean of 10.1 for a sample of 139 valves. Some individuals in populations of C. jeffersonius jefferson- ius from the upper part of Mansfield's zone 1 exhibit characteristics transitional to those found in C. jeffersonius septenarius, which is the prevalent form in the lower part of zone 2 of Mansfield. Samples of C. jeffersonius jeffersonius are characterized by a greater number of plicae, with a mean of 10.1 versus 6.9 for C. jeffersonius septenarius in the Lee Creek samples, but there is some overlap between the two subspecies (Figure 23). Typical members of C. jefferson- ius jeffersonius have plicae rounded in cross-section, lacking the flattened tops and square sides characteristic of C. jeffersonius septenarius (Plate 22: figures 3, 4), although there is gradation between the two forms in the youngest members of C. jeffersonius jeffersonius. The plicae in C. jeffersonius jeffersonius are actually broader than those of C. jeffersonius septenarius, probably due to the vertical sides in the latter form. In C. jeffersonius jeffersonius the plicae are lower in relation to the width (Figure 24). The height of 70 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY n C. jeffersonius septenarius C. jeffersonius jeffersonius C. madisonius NUMBER OF PLICAE FIGURE 23.—Histogram ofthe number of plicae in various subgroupings of C/!«a/)?c<«'n from the Yorktown Formation in the Lee Creek Mine. the plicae in relation to width becomes proportionally less in the larger, older individuals. The .scabrous nature ofthe costae is less developed in (C. jeffersonius jeffersonius. The convexity of the valve is slightly less in both the right and left valves of (C. jeffersonius jeffersonius, but this appears to be primarily a result of greater height of the plicae in (C. jeffersonius septenarius rather than to a basically more con- vex shape of the valve. In other shell characters, such as length of hinge line, size of auricles, and shape of disk, no differences could be noted between the two subspecies. (C. jeffersonius septenarius tends to have a deeper bys.sal notch with increasing size, but larger populations of both subspecies with an intact bys.sal notch will be necessary to confirm this. Becau.se ofthe general similarity of morphology between the two subspecies, except for characteristics of the plicae, and because even in the plicae there is transition between the two groups in the upper part of zone 1 of Mansfield, the two groups are considered chronologic subspecies rather than separate species. STRAIIGRAPHIC AND GEOGRAPHIC RANGE.—In the Lee Creek Mine, specimens occur commonly in units 1 to 3 of the Yorktown Formation of Gibson (1967); specimens in unit 3 are transitional to (C. jeffersonius septenarius. This subspec ies has been reported from Mansfield's zones 1 and 2 of the Yorktown Formation in Virginia and North Caro- lina. It is likely that most or all of the occurrences in zone 2 should be referred to (C. jeffersonius septenarius and that (C. jeffersonius jeffersonius IS chsLVdclensUc of /.one 1 only. In addition, the subspecies is found in roughly time-equivalent Pliocene strata southward through South Carolina and Georgia into Florida. MEASURED MATERIAL.—Total specimens measured of (Chesapecten jeffersonius jeffersonius include 27 right valves and 19 left valves (USNM 363017, 363019-363021) from US(;S 25338 and 1 right valve and 1 left valve (USNM NUMBER 61 71 C. jeffersonius jeffersonius • right valve O left valve C. jeffersonius septenarius ▲ right valve A left valve A AA O^O o^ OAOOA WIDTH OF PLICA FIGURE 24.—Bivariate scatter diagram showing the greater height of the plica in relation to the width in Chesapecten jeffersonius septenarius than in C. jeffersonius jeffersonius from the Yorktown Formation in the Lee Creek Mine. TABLE 15 —Measu rements [in mm) of a representative sample of Chesapecten jeffersonius jeffersonius. Character USNM 363017 USNM 363018 USNM 363019 USNM 363020 USNM 363021 (D) (S) (D) (S) (S) (D) H 86 123 123 75 27 29 AHL 46.0 63.0 64.0 38.0 12.0 14.5 PHL 50.0 67.0 67.0 40.0 13.0 14.5 L 96 130 131 78 25 29 ADHD 39 60 60 35 16 16 PDHD 40 65 62 37 16 18 CON 16.4 27.4 21.6 16.7 8.1 5.6 HAA 15.0 23.0 20.0 15.0 7.5 5.5 HPA 16.0 29.0 28.0 15.0 7.0 7.5 LAA 25 31 33 20 8 9 LPA 25 32 31 19 8 8 HL 50 63 64 39 16 17 DBN 22.0 - 32.0 - - 6.5 BN 3.0 - 1.0 - - 2.5 WP 10.6 12.2 14.4 6.9 3.2 3.4 Wl 5.8 10.5 9.5 5.6 3.0 1.8 HR 5.4 6.4 6.0 4.7 3.2 2.8 NRIB 10 9 9 11 8 10363018) from USGS 25339. Both USGS collections are from spoil banks of Yorktown Formation in the Lee Creek Mine, North Carolina. Measurements (in mm) from a rep- resentative sample of 6 valves are given in Table 15. Chesapecten jeffersonius septenarius (Say) PLATE 21: FIGURES 7, 8; PLATE 22: FIGURES 2, 3; PLATE 23: FIGURES 1-3, 6, 7; PLATE 24: FIGURES 1, 2; PLATE 25: FIGURE 5; PLATE 26: FIGURE 2 Pecten septenarius Say, 1824:136, pl. 9: fig. 3. Pecten Jeffersonius var. septenarius Say.—Dall, 1898:722. Pecten (Chlamys) jeffersonius septenarius Say.—Mansfield, 1936:174-175, 179,184-185. Chlamys (Lyropecten) jeffersonius septenarius (Say).—Tucker-Rowland, 1938:20-21, pl. 3: fig. 15. Chesapecten septenarius (Say).—Ward and Blackwelder, 1975:15-16, pl. 6:figs. 5-7, pl. 7: figs. 2, 9. DESCRIPTION.—Shell Outline: Shell large, attaining height of 132 mm; both valves convex, with left valve moderately convex and right valve of low convexity. Outline of disk almost equilateral with slight posterior obliqueness; 72 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY shells slightly longer than high, more pronounced in larger specimens. No disk gape. Auricles and Outer Ligament: Right anterior auricle with planar surface; dorsal margin nearly coincident with groove of outer ligament and slightly folded; byssal notch of mod- erate depth with subangular apex; byssal fasciole poorly developed; ctenolium with 3 or 4 teeth well developed in specimens up to 75 mm height, absent in larger individuals. Left anterior auricle with concave surface; dorsal margin flat and coincident with trace of outer ligament; free margin curved with a moderately broad and shallow byssal sinus. Posterior auricles similar in size to anterior; surfaces planar to slightly concave; free margins curves. Anterior and pos- terior outer ligaments about equal in length. Moderate auricular gape anteriorly and posteriorly. Exterior Shell Surface: Valves with 6 to 8 large plicae; in early growth stages plicae have vertical sides and a flat summit with an overhanging edge; in later stages plicae lose the overhanging edge and may retain vertical sides or become slightly sloping; plicae slightly wider than inter- spaces. Radial costae are strongly developed on shell and have a scabrous appearance where crossed by the concentric lamellae; costae number as many as 20 on the summit of the plicae, up to 9 on the sides of the plicae, and as many as 15 in the interspaces; costae are of varying strengths and additional ones come in by intercalation. Concentric lamel- lae well developed over the valves. Auricles have about 25 costae of about equal strength; well-developed concentric lamellae give a scabrous appearance. Disk flanks steep and covered with fine costae. Interior Features: Resilial insertion about I '/2 to 2 times as high as long; oriented with a slight posterior slope; single weakly developed auricular denticle both anteriorly and posteriorly. DISCUSSION.—A gradational change in the characteristics of (C. jeffersonius occurs vertically through the Yorktown Formation. In the uppermost part of Mansfield's zone 1, the population samples contain some individuals with fewer plicae that have square sides and are moderately high in the early ontogenetic stages. In the lower part of zone 2 these characteristics are well developed throughout the ontogeny of most individuals and dominate the populations. The populations in zone 2 are considered a chronologic subspe- cies, (C. jeffersonius septenarius, in which the gradational change from its predecessor, (C. jeffersonius jeffersonius, takes place during the upper part of zone I. Chesapecten jefferson- ius septenarius is very similar to its ancestral form in most characteristics, but it is decidedly different in the characters of the plicae. The younger subspecies has fewer plicae, ranging from 6 to 8 with a mean of 6.9 (Figure 23) for the Lee Creek sample compared to a range of 8 to 12 with a mean of 10.1 for the .sample of C. jeffersonius jeffersonius from the Lee Creek Mine. In addition, the plicae in (C. jeffersonius septenarius are higher in relation to the width (Figure 24), and have a squared cross-sectional profile with flattened sunnnits and vertical sides. In the early and middle stages of ontogeny the plicae exhibit an overhang at the edge (Plate 22: figure 3), although the plicae become more rounded in later growth stages. Other morphologic differ- ences are the presence in (C. jeffersonius septenarius of a more strongly developed scabrous ornamentation, a deeper byssal notch and sinus, and the thickening ofthe early part ofthe interior of the shell by additional shell layers. The shell thickening is similar to that found in C. madisonius, but it does not reach the thickness found in later forms of C. madisonius. An additional subspecies from the Yorktown Formation, (C. jeffersonius palmyrensis, was described by Mansfield (1936) from Palmyra Bluff on the Roanoke River in North Carolina, a locality he placed in the lower part of his zone 2. The holotype is the only known complete specimen in the USNM collections. It was characterized by Mansfield as having four high, very broad plicae with fiattened summits. The plicae have overhanging edges in the umbonal area. Although Mansfield mentioned only four plicae, there is a small plica on each margin of the holotype, which is re- flected on the interior of the shell, giving a count of six plicae by the writer's method. Fragments of valves having similarly large plicae have been found at several localities in the Yorktown Formation in North Carolina. Because of the absence of adequate samples, it is uncertain whether the holotype is an extreme variant of C. jeffersonius septenarius TABLE 16.—Measurements (in mm) of a representative sample of Chesapecten jeffersonius septenarius. Character USNM 218910 USNM 218915 USNM 363022 USNM 363023 USNM 363024 (S) (D) (D) (S) (D) (S) H 73 73 104 132 35 31 AHL 38.0 37.0 53.0 60.0 15.5 14.0 PHL 40.0 41.0 61.0 78.0 18.0 15.5 L 78.0 48.0 114.0 138.0 33.5 29.5 ADHD 36 40 52 60 18 19 PDHD 40 44 56 72 22 18 CON 21.6 15.5 28.3 38.1 7.2 7.9 HAA 18.0 15.5 20.5 30.0 7.0 9.0 HPA 18 18 21 27 7 8 LAA 24.0 25.0 - 33.0 10.5 9.0 LPA 23 23 33 38 10 9 HL 47.0 48.0 - 71.0 20.5 18.0 DBN - 17 29 - 7 - BN - 8.0 - - 3.5 - WP 10.1 13.1 16.1 15.1 5.2 3.8 Wl 12.0 8.8 14.5 14.2 3.9 3.9 HR 10.4 8.8 9.9 11.5 4.4 4.3 NRIB 6 7 7 7 7 7NUMBER 61 73 or subspecifically distinct. For the present it is retained as a separate taxon. STRATIGRAPHIC AND GEOGRAPHIC RANGE—In the Lee Creek Mine, specimens occur fairly commonly in units 3 to 5 ofthe Yorktown Formation of Gibson (1967). Specimens of this subspecies are connnon in the lower part of Mans- field's zone 2 of the Yorktown Formation but become rare in the upper part of the zone. The subspecies is found in the Yorktown Formation from the York River in Virginia southward to the Lee Creek Mine in North Carolina. MEASURED MATERIAL—Total specimens measured of (Chesapecten jeffersonius septenarius include 20 right valves and 15 left valves (USNM 218910, 218915, 363022- 363024) from USGS 25338, collected from spoil banks of the Yorktown Formation in the Lee Creek Mine, North Carolina. Measurements (in mm) from a representative sample of 6 valves are given in Table 16. Chesapecten madisonius (Say) PLATE 22: FIGURE 1; PLATE 24: FIGURES 3-5; PLATE 25: FIGURES 1-4, 6; PLATE 26: FIGURES 1, 3-5 Pecten Madisonius Say, 1824:134 [not Pecten madisonius of authors subse- quent to Say]. Pecten Edgecombensis Conrad, 1862:291. Pecten jeffersonius edgecombensis Conrad.—Mansfield, 1936:174-175, 179, 184-185. Chlamys (Lyropecten) jeffersonius edgecombensis (Conrad).—Tucker-Rowland, 1938:15-16, pl. 2: fig. 5, pl. 4: fig. 6. Chesapecten madisonius (Say).—Ward and Blackwelder, 1975:16-18, pl. 6: figs. 1-4; pl. 7: figs. 1, 7, 8. DESCRIPTION—Shell Outline: Shell of large size, attain- ing height of 133 mm; both valves of low to moderate convexity, with left valve more convex than right; convexity reaches 27 mm in left valves and 23 in right. Outline of disk equilateral; shells slightly longer than high, more pro- nounced in larger specimens. No disk gape. Auricles and Outer Ligament: Right anterior auricle with planar surface; dorsal margin nearly coincident with groove of outer ligament and slightly folded; byssal notch of mod- erate depth with subangular apex; byssal fasciole poorly developed; ctenolium with 3 or 4 teeth well developed in specimens up to height of 65 mm, absent in larger individ- uals. Left anterior auricle with concave surface; dorsal margin flat and coincident with trace of outer ligament; free margin curved with a broad and moderately shallow byssal sinus. Posterior auricles similar in size to anterior; surfaces planar to slightly concave; free margins straight and perpendicular to hinge line. Anterior and posterior outer ligaments about equal in length. Moderate auricular gape anteriorly and posteriorly. Exterior Shell Surface: Valves with 10 to 17 plicae; in early growth plicae have vertical sides with a flat summit; in later growth stages plicae have rounded summits and sloping sides; plicae wider than interspaces. Radial costae well developed on shell and have a scabrous appearance where crossed by the concentric lamellae; costae number as many as 10 on the summit ofthe plicae, up to 4 on the sides of the plicae, and as many as 7 in the interareas; costae are of varying strengths and additional ones come in by inter- calation. Concentric lamellae well developed over the valves. Auricles have as many as 30 costae of about equal strength; well-developed concentric lamellae give a scabrous appearance. Disk flanks steep on left valves, moderately sloping on right, covered with costae. Interior Features: Resilial insertion about l!/2 times as high as long; oriented with a slight posterior slope; single weakly developed auricular denticle, both anteriorly and posteriorly. DISCUSSION.—Ward and Blackwelder (1975) reinstated the name C. madisonius Say on the basis of this name having been applied to a different species than what they deter- mined to be the type lot in the Academy of Natural Sciences of Philadelphia. As Mansfield (1936:184) indicated, C. madisonius (= C. edgecombensis of authors subsequent to Say) is part ofthe C. jeffersonius lineage and appears at approximately the same time as (C. jeffersonius septenarius. The appearance of the two taxa indicates a splitting of the C. jeffersonius stock according to Mansfield's (1936) phylogeny. Although pop- ulations of C. jeffersonius septenarius are characterized by fewer plicae compared to the present C. jeffersonius jeffer- sonius stock, populations of C. madisonius have a greater number of plicae. C. madisonius from the Lee Creek Mine have from 10 to 17 plicae with a mean of 14.8 compared to 10.1 for C. jeffersonius jeffersonius (Figure 23). Strati- graphically younger populations of C madisonius from other localities have a higher mean number. The plicae in C. madisonius are considerably lower than in subspecies of C. jeffersonius, and they are rounded in cross-section (Plate 22: figures 1-4) in contrast to the squared plicae in the time- equivalent populations of C jeffersonius. The anterior and posterior auricles of Chesapecten madi- sonius are essentially equal in height on each value in con- trast to the right valve of both subspecies of C. jeffersonius in which the posterior auricle is higher than the anterior one. The depth of the byssal notch is comparable to C. jeffersonius, but it is most similar to the population of C. jeffersonius septenarius, which has a slightly deeper notch. C. madisonius is also similar to C. jeffersonius septenarius in the thickening ofthe shell by the addition of calcite to the inside ofthe valve. In (C. madisonius the thickness becomes greater in the later forms and is considerably thicker than found in the other forms of the lineage. Although the convexity of the valves is similar between C. madisonius and C. jeffersonius jeffersonius, it is consistently less in the former than in the 74 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY time equivalent populations of C. jeffersonius septenarius. The right valve of C madisonius is comparatively less convex than the left in relation to C. jeffersonius. The scabrous ornamentation is not as strongly developed in this species as it is in C. jeffersonius. The early and middle ontogenetic stages of (C. madisonius have only three costae on the summits of the plicae (Plate 24: figure 5), and are probably the source of reports of C. madisonius (= C. nefrens of Ward and Blackwelder) from the Yorktown Formation. The increased number of costae on the plicae during on- togeny arise by intercalation. The lesser number of costae in (C. madisonius mainly is a reflection ofthe greater number of plicae, and thus narrower width of each plica. In most characteristics the population of (C. madisonius from the Lee Creek Mine is of an early to middle stage of development, not the latest, ofthe C. madisonius lineage. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—In the Lee Creek Mine, this species is found in units 3 to 5 of the Yorktown Formation of Gibson (1967), where it is moder- ately common. The species occurs in Mansfield's zone 2 of the Yorktown Formation from the York River in Virginia southward to the Lee Creek Mine in North Carolina. It is a useful guide fossil to zone 2. MEASURED MATERIAL.—Total specimens measured of (Chesapecten madisonius include 7 right valves and 7 left valves (USNM, 218908, 218916, 218919, 363025) from USGS 25338, collected from spoil banks of Yorktown For- mation in the Lee Creek Mine, North Carolina. Measure- ments from a representative sample of 6 valves are given in Table 17. TABLE 17.—Measurements (in mm) of a repi-esentative sample of Chesapecten madisonius. Character USNM 218908 (D) USNM 218916 USNM 218919 USNM 363025 (S) (D) (D) (S) (S) H 130 66 64 82 83 133 AHL 66 32 31 45 41 68 PHL 74 35 35 42 44 70 L 140 67 66 87 85 138 ADHD 62 33 31 44 38 62 PDHD 74 36 33 43 46 68 CON 22.8 13.0 8.4 - 26.3 HAA 23 16 13 16 17 27 HPA 27 15 14 17 18 32 LAA 40 21 21 28 24 37 LPA 38 18 18 23 24 55 HL 78 39 39 51 48 72 DBN 34 - 15 20 BN 6 6 8 WP 8.9 3.9 3.8 - 8.6 Wl 6.2 2.4 3.2 - 5.3 HR 4.6 2.9 2.7 3.1 4.4 NRIB 15 16 16 16 15 16Chesapecten coccymelus (Dall) PLATES 27-30 Pecten (Chlamys) coccymelus Dall, 1898:741-742, pl. 34: fig. 1.—Glenn, 1904:374-375, pl. 99: fig. 3. Chlamys (Chlamys) coccymelus (Dall).—Rowland, 1936b: 1007-1008, pl. 8: figs. 3-4. Chlamys (Lyropecten) madisonius bassleri Tucker-Rowland, 1938:13-14, pl. .5:fig. 1. Chesapecten coccymelus (Dall).—Ward and Blackwelder, 1975:8-9, pl. 3: figs 1,2, pl. 7: figs. 14, 15. DESCRIPTION.—Shell Outline: Shell of medium size, at- taining height of 58 mm; both valves of moderate convexity, with left valve more convex than right. Outline of disk equilateral; smaller valves slightly higher than long, larger valves of equal height and length; slight disk gape anteriorly and posteriorly. Auricles and Outer Ligament: Right anterior auricle with planar surface; donsal margin slightly dorsal to groove of outer ligament and strongly folded; byssal notch deep with an anuglar apex with a 60 to 90 degree angle; byssal fasciole broad, arched near disk, concave away; ctenolium with 4 or 5 teeth well developed throughout all growth stages. Left anterior auricle with concave surface; dorsal margin flat and coincident with trace of outer ligament; free margin slightly curved with a shallow byssal sinus. Posterior auricles much smaller than anterior; surfaces planar to slightly con- cave; free margins nearly straight, with posterior slope. Anterior outer ligament about 1 '/2 to 2 times as long as posterior. Exterior Shell Surface: Valves with 17 to 19 prominent plicae; plicae have vertical to steeply sloping sides through- out the valve; plicae slightly wider than interspaces. Radial costae strongly developed on shell, with coarsely scabrous appearance where crossed by the concentric lamellae; costae vary in number from 1 to 4 on the summits of the plicae with 3 being the most common; early ontogenetic stages may have only 1 costa on each plica, with the 2 lateral ones being added later; the median costae on the plicae are stronger in develo|)ment than the lateral ones; the sides of the plicae have 1 to 3 finely scabrous plicae; the interspaces commonly have 3 scabrous plicae with the central one being considerably stronger; all costae have stiongly projecting spines, which may be recurved toward the umbo. Right anterior auricle has 6 coarse costae and may have 1 or 2 weakly developed ones intercalated between the more ven- tral strong ones; well developed but weakly spinose lamellae; other auricles with 8 to 15 fine costae, strongly spinose. Disk flanks on right valves have moderate slope, and have several fine costae; left valves have steep disk flanks with 5 or 6 scabrous costae. Interior Features: Resilial insertion somewhat higher than long; oriented with a slight to moderate posterior slope; single auricular denticle weakly developed both an- teriorly and posteriorly. NUMBER 61 75 DISCUSSION.—A number of workers, including Tucker- Rowland (1938), Schoonover (1941), and Mongin (1959) have separated the populations of Pecten madisonius (= C. coccymelus) that occur in the Calvert and Choptank forma- tions in Maryland into two groups, primarily on the basis of shell size and ornamentation. These consist of a group of small, thin-valved specimens with rows of distally concave spines found in the middle part of the Calvert Formation (bed 10 at Plum Point), and a second group of considerably larger, thicker-valved specimens with considerably less scaly ornamentation, which occur in the upper part ofthe Calvert and the overlying Choptank Formation. Schoonover (1941) and Mongin (1959) did not propose new names for these groups, although they noted the differences between them. Tucker-Rowland (1938:11) did use Chlamys (Lyropecten) madisonius acanikos (Gardner), a form originally described from the Miocene deposits in Florida, for part ofthe group found in the Calvert Formation at Plum Point. She (Tucker- Rowland, 1938:13) also named a new subspecies, Chlamys (Lyropecten) madisonius bassleri, for part of the complex group found in the Calvert Formation. Chlamys coccymelus was considered to be a rare, but close relative of the other forms found in bed 10. Ward and Blackwelder (1975) proposed that the speci- mens within the populations from bed 10 of the Calvert Formation had a continuous range from forms carrying three rows of distally concave spines to the forms of Chesa- pecten coccymelus, which is an end member carrying only one row. This would include most of the bed 10 forms in the senior name, C. coccymelus. My examination of population samples taken from bed 10 at two localities near Plum Point supports this treatment. The type specimen of C. coccymelus (Plate 29: figure 5) is a relatively small left valve, 30 mm high, which has only one row of spines on the plicae. It has a row of moderate spines in the interspaces and one or more rows of smaller spines. The more common forms of small Chesapecten found in bed 10 have three rows of spines on the plicae, although the three rows usually are not equal, the central row being larger than the two lateral ones. The two lateral rows of spines are added at some distance from the origin of growth and become progressively stronger in development (Plate 30: figures 2-4). The place of insertion of the two lateral rows may be within a few millimeters of the origin of growth or as much as 20 mm below the point. In smaller individuals single rows of spines on the plicae are common. The development of a single row of spine is predominantly confined to the left valves. The type speci- men of C. coccymelus is a left valve, which would contribute to the extreme form of ornamentation. Most right valves have three rows of spines but a few have four rows (Plate 28: figure 3). Another variation in the ornamentation is the common appearance on a single individual at a similar growth stage of plicae bearing three rows of spines and plicae having just a single row (Plate 30: figure 3). Chlamys (Lyropecten) madisonius bassleri Tucker-Rowland, 1938, is one of the ornamental variations of Cheaspecten coccymelus found in bed 10 at Plum Point. The holotype of C. m. bassleri (Plate 29: figures 1-3) has a median row of large spines surrounded by two lateral rows of smaller spines on the more ventral part of the valve, but the early part of the valve up to a distance of approximately 17 mm from the origin of growth has the single row of spines character- istic of C. coccymelus. This specimen also illustrates the variation found in the rows of spines in the interspaces; some interspaces have one dominant row of spines, while other interspaces have two or three essentially equally de- veloped rows of spines. The specimens found in the upper part of the Pungo River Formation in the Lee Creek Mine include three complete right valves and fragments of other specimens. These specimens from the Pungo River Formation compare well with the population samples from bed 10 ofthe Calvert Formation at Plum Point, Maryland. A population study was made involving 17 morphologic characters, and the Lee Creek specimens fall well within the range of variation of the population sample from the Calvert Formation in all characters. The depth ofthe byssal notch is one ofthe more important characteristics distinguishing C. coccymelus from the stratigraphically younger species of Chesapecten. Com- parison of the specimens from the Pungo River Formation in North Carolina and the Calvert Formation in Maryland indicates no difference in this character (Figure 25). Other characteristics exhibit a similar pattern. The specimens from the Pungo River Formation in North Carolina have a consistency in the ornamentation, with three well-developed rows of spines on the plicae ofthe right valve (with a fourth being found on the largest valves) and a dominant row of spines in the middle of the interspaces. The samples from the Pungo River Formation does not contain all of the variation in ornamentation found in the samples from the Calvert, such as single rows of spines on the plicae, but this could be due to the relatively small number of specimens recovered. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—This species is found in the upper 6 to 12 feet (1.8 to 3.7 m) of the Pungo River Formation in the Lee Creek Mine. It is fairly common in the bryozoan shell hash zone that comprises the uppermost 2 to 3 feet (0.6 to 0.9 m) in the test pit (unit 7 of Gibson, 1967), and also in the limey and indurated intervals in the underlying interbedded limestone and phos- phatic sand units (units 4 to 6). This species previously has been reported from the middle and lower parts of the Calvert Formation, occurring in bed 10 (Ward and Black- welder, 1975:9) and possibly as far down in the Calvert as bed 2 (Schoonover, 1941:196, reported as Chlamys madison- ius). It is a reliable index to the Calvert Formation and serves a similar function in the Pungo River Formation in North Carolina. MEASURED MATERIAL—Total specimens measured of Chesapecten coccymelus include 3 right valves (USNM 76 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY mm 12|— J \ L J \ L 8 10 12 14 LENGTH OF ANTERIOR OUTER LIGAMENT • C. coccymelus (Calvert) ^ C. coccymelus (Lee Creek) I I I I I 18 16 22 FIGURE 25.—Bivariate scatter diagram showing similarity of depth ofthe byssal notch between samples of Chesapecten coccymelus from the Calvert Formation, Maryland, and from the Pungo River Formation in the Lee Creek Mine. TABLE 18.—Measurements (in mm) of a representative sample of Chesapecten coccymelus. USNM USNM USNM USNM USNM USNM USNM Character 218922 218924 218925 363026 363027 363028 363029 (D) (D) (D) (D) (D) (D) (D) H 54.0 52.3 58.0 34.5 46.0 31.0 18.0 AHL 27.5 - 27.0 16.0 22.0 15.0 8.0 PHL 29 - 30 18 24 15 8 L 56.5 53.6 57.0 34.0 46.0 30.0 16.0 ADHD 29 - 31 18 23 22 10 PDHD 29 - 29 17 26 22 11 CON 11.5 8.0 9.4 5.2 8.3 5.3 3.2 HAA 9.0 9.2 10.0 5.5 8.5 6.0 3.5 HPA 13.5 14.0 12.0 8.0 10.5 7.0 5.0 LAA 19.0 19.0 20.5 11.5 16.5 11.5 6.5 LPA - 9.0 10.0 7.0 3.5 HL - 20.5 26.5 18.5 lO.O DBN 10.0 10.0 10.5 5.2 8.5 6.0 3.5 BN 9.0 9.0 10.0 6.3 8.0 5.5 3.0 WP 2.8 2.6 1.2 2.3 1.1 - Wl 3.3 - 3.6 1.8 3.1 1.7 NRIB 19 19 17 18 17 19 18 218922, 218924, 363026) from USGS 25338, 13 right valves from USGS 25344, and 19 right valves (USNM 218925, 363027-363029) from USGS 25345. Those from USGS 25338 are from .spoil banks of the Pungo River Formation at the Lee Creek Mine, North Carolina; those from USGS 25344 are from the Calvert Formation, 1.5 miles south of Plum Point, Maryland; tho,se from USGS 25345 are from the Calvert Formation at Camp Roosevelt, Maryland. Measurements from a representative sample of 7 valves are given in Table 18. Chesapecten nefrens Ward and Blackwelder PLATE 31: FIGURE 7 Pecten Madisonius.—Conrad, 1840:48, pl. 24: fig. 1 [not Pecten madisonius Say, 1824]. Pecten (Chlamys) madisonius.—Glenn, 1904:377, pl. 100: fig. 1.—Mansfield, 1936:174-177, 184. Chlamys (Lyropecten) madisonia.—Tucker-Rowland, 1938:9-11, pl. 1: figs. 1-2.—Gardner, 1944:32, pl. 4: fig. 5, pl. 9: fig. 7. Chlamys (Lyropecten) madisonius.—Schoonover, 1941:192-201, pl. 21: figs. 1-3, pl. 22: fig. 4, pl. 23: fig. 3. Chlamys madisonia.—Mongin, 1959:309-314, pl. 26: figs. la-b. Chesapacten nefrens Ward and Blackwelder, 1975:9-10, pl. 2: figs. 4-6, pl. 3: figs. 4-7, pl. 4: figs. 1-2, pl. 7: figs. 6, 13. DESCRIPTION.—Shell Outline: Shell large, with height of 95 mm; right valve of moderate convexity. Outline of disk equilateral; valve longer than high. Auricles and Outer Ligament: Right anterior auricle with planar surface; dorsal margin slightly dorsal to groove of outer ligament and strongly folded; byssal notch deep with angular apex with an 80 degree angle; byssal fasciole broad, arched near disk, planar away; ctenolium with 4 teeth well developed in adult form. Right posterior auricle with planar surface; dorsal margin slightly dorsal to groove of outer ligament; free margin straight, sloping posteriorly. Anterior outer ligament about I'/2 times as long as posterior. Exterior Shell Surface: Valve with 19 plicae; plicae of moderate height with steep sides; plicae wider than inter- NUMBER 61 77 spaces. Radial costae strongly developed on shell and have a coarsely scabrous appearance where crossed by the con- centric lamellae; 3 costae on the summits of the plicae, the 2 lateral ones being weaker in the early stages and of equal strength in the later; interspaces have 3 costae, with the central one being considerably coarser than the lateral ones; costae have moderately projecting spines or scabrous ap- pearance. Right anterior auricle has 7 moderately coarse costae with low scabrous ornamentation; right posterior auricle has 12 fine costae with scabrous nature. Disk flanks of moderate slope and having several costae. Interior Features: Resilial insertion somewhat higher than long, oriented approximately perpendicular to the hinge line; single auricular denticle weakly developed both anteriorly and posteriorly. DISCUSSION.—The single specimen found in the Lee Creek Mine is probably typical of the stratigraphically ear- lier members of C. nefrens. C. nefrens differs from C. coccy- melus in being larger in size, having a greater length in relation to height of the disk, in having a longer posterior auricle in relation to the anterior, in having low scabrous costae on the plicae rather than rows of highly recurved spines, and in having a lower and less pronounced plicae. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—One speci- men was collected from the uppermost bed of the Pungo River Formation in the Lee Creek Mine (unit 7 of Gibson, 1967). Schoonover (1941) and Ward and Blackwelder (1975) give the stratigraphic occurrence of this species as from bed 14 of the Calvert Formation to bed 19 of the Choptank Formation in Maryland. In the Calvert Cliffs section in Maryland, C. coccymelus occurs in bed 10 (Ward and Blackwelder, 1975:9) and probably below bed 10 (Schoonover, 1941:196, reported as Chlamys madisonius). However, both species are found within the upper bed in the Lee Creek Mine, although only C. coccymelus has been found below the upper bed. MEASURED MATERIAL.—Measurements of a single speci- men of Chesapecten nefrens (USNM 218932) from USGS 25749, Pungo River Formation at the Lee Creek Mine, North Carolina, are given in Table 19. TABLE 19.—Measurements (in mm) of a specimen of Chesapecten nefrens. USNM USNM Character 218932 Character 218932 (D) (D) H 95 HPA 17 AHL 54 LAA 29 PHL 53 LPA L 107 HL CON 17.6 DBN 16 HAA 13 BN 13 NRIB 19Genus Amusium Roding, 1798 Amusium sp. PLATE 31: FIGURES 3, 4 DISCUSSION.—The material from the upper part of the Pungo River Formation in the Lee Creek Mine consists of three fragments, each several inches in length. The Lee Creek fragments differ in several characteristics from Amu- sium mortoni (Ravenel), the common species of Amusium occurring in the Pliocene and Pleistocene deposits from Virginia to Mexico (Gardner, 1944:39). Although the spec- imens from the Pungo River Formation have approximately the same moderate convexity of the valve and slight con- centric corrugation on the exterior of the valve without radial ornamentation, they are considerably thicker in shell cross-section and have widely separated paired lirae inter- nally (Plate 31: figure 3). This is in contrast to the thin shell and the closely spaced double lirae found in A. mortoni (Plate 31: figure 1). The fragments do not allow comparison of other morphologic features. As A. mortoni has consist- ently thin valves and equidistant spacing of interior lirae over its wide geographic and stratigraphic range, it appears that the Lee Creek specimens belong to a different and probably new species. Glenn's (1904:373) report of speci- mens of A. mortoni from the St. Marys Formation in Mary- land is in error, apparently as a result of misreading the labels (USGS 2831 and 2835 were read as 2331 and 2325); the specimens in question actually come from the upper part of the Yorktown Formation near Suffolk, Virginia, in line with other reports of the age of the species. Thus, the Lee Creek material is considerably older in age than the reported range of A. mortoni. Amusium precursor (Dall, 1898) occurs in the Miocene Chipola Formation in Florida, a unit close in age to the Pungo River Formation (Gibson, 1967:643; Akers, 1972:9). Thus, A. precursor is of a generally comparable age to the specimens found in the Lee Creek Mine, but differs in having uniformly closely spaced internal lirae and finely impressed radial lines on the exterior. As Dall (1898) did not select a holotype or illustrate any specimens of A. precursor, a lectotype is here selected and a lectoparatype illustrated (Plate 31: figures 5, 6). The lecto- type is an articulated specimen, USNM 647532, from USGS 2213 in the Chipola Formation, one mile (1.6 km) below Bailey's Ferry, Chipola River, Florida. A number of prob- lems are encountered in the selection of the lectotype. Among localities mentioned by Dall (1898:755) in his de- scription of the species are Alum Bluff, from which no material could be found in the museum collections, and others along the Chipola River. Gardner (1926:50) and other writers have taken USGS 2212 (Chipola Formation at Ten Mile Creek) as the type locality, possibly because the 78 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY label in the museum collections says "type locality" com- pared with "cotype locality" for USGS 2213; however, this entry of unknown origin has no standing. In the USNM catalogue for the lots from these localities, the number of specimens listed is fewer than are now in the type lots, indicating that specimens were added to the type lots, whether before or after Dall described this species is not known. The only specimen that can be identified unequiv- ocally with Dall's original material is the largest specimen from USGS 2213, which agrees with measurements given in the original description. Therefore this specimen is picked as the lectotype. All the material in the lots from USGS 2212, 2213, and 2564 will be considered lectopara- types as there is no feasible way to determine if, or which, specimens may have been added to the type lots, and all the material appears to be conspecific. A lectoparatype is illus- trated (Plate 31: figures 5, 6) to show the interior lirae, as the lectotype is an indurated double valve, the interior of which cannot be observed. Most recovered fossil specimens of Amusium are fragmen- tary and do not show many ofthe shell characteristics, such as byssal notch and auricles. From the present observations it appears that the internal lirae are distinct specific char- acters. The three species examined here illustrate differ- ences in internal lirae (Plate 31: figures 1, 3, 6). The paired lirae in specimens from the Lee Creek Mine are separated by wide interspaces, varying from 9 to 10 mm between pairs and also have a wide distance of 7 to 8 mm between lirae of a pair. The lirae in A. precursor do not appear in pairs, but as closely spaced independent ones, varying in spacing from 1 to slightly over 2 mm within a single speci- men. The lirae in A. mortoni occur in pairs, with a very close spacing of 0.2 to 0.5 mm between the lirae within a pair, and with a relatively wide spacing of 3.5 to 5.0 mm between the pairs in the illustrated specimen (Plate 31: figures 1, 2) with a height of 73 mm. Thus it appears that the character- istics ofthe internal lirae are of considerable help in defining the species, particularly because of the fragmentary nature of most specimens. STRATIGRAPHIC AND GEOGRAPHIC RANGE.—The only known specimens of this possibly new Amusium sp. occur in the limy interbedded layers (units 4-6 of Gibson, 1967) in the upper part of the Pungo River Formation in the Lee Creek Mine. List of Localities USGS LOCALITIES 2025 Darlington County, South Carolina: Shell Branch, I mile (1.6 km) east of Darlington Court House. 2106 Frank Burns, collector, 1886. Duplin Formation. Cumberland County, New Jersey: marl beds near Jericho. Frank Burns, collector, 1887. Kirkwood Formation. 2212 Calhoun County, Florida: Ten Mile Creek, 1 mile (1.6 km) west of Bailey's Ferry on the Chipola River. Frank Burns, collector, 1889. Chipola Formation. 2213 Calhoun County, Florida: Chipola River, 1 mile 2564 3915 (1.6 km) below Bailey's Ferry. Frank Burns, col- lector, 1889. Chipola Formation. 2447c Calvert County, Maryland: Blakes Cliffs, about 3 miles (4.8 km) north of Plum Point wharf Burns and Harris, collectors, May 1892. Calvert Formation. 2452 James City County, Virginia: "Grove Wharf" on James River, 9 miles (14.5 km) west of Yorktown and 9 miles (14.5 km) south of Williamsburg. Frank Burns, collector, 1892. Yorktown For- mation. Calhoun County, Florida: McClelland Farm, 1 mile (1.6 km) below Bailey's Ferry, Chipola River. Frank Burns, collector, 1889. Chipola Forma- tion. Middlesex County, Virginia: river front at Ur- banna, between mouth of creek and wharf of Weems Line of steamers on Rappahannock River. Frank Burns, collector, 1903. Lowermost part of Yorktown Formation (= "Virginia St. Marys" beds of Mansfield). 3924 Essex County, Virginia: right bank of Rappahan- nock River at a very high bluff locally known as "Jones Point," I mile (1.6 km) north or up the river from "Bay Port" wharf, about 13 miles (21 km) north of Urbanna. Frank Burns, collector, 1903. Lowermost part of Yorktown Formation (= "Virginia St. Marys" beds of Mansfield). 8179 Essex County, Virginia: right bank of Rappahan- nock River about 0.5 mile (0.8 km) downstream from Jones Pt. or 0.5 mile (0.8 km) northeast- ward from Butylo. W.J. Lee, collector, 1918. Most of this material was picked up from beach, not obtained in place in bank. Lowermost part of Yorktown Formation (= "Virginia St. Marys" beds of Mansfield). 10278 Anne Arundel County, Maryland: Howard Post Office. John Shepherd, collector, 1922. Calvert Formation. 10962 Liberty County, Florida: cut in road leading to Watsons Landing. W.C. Mansfield and E.C. Bracewell, collectors, 1925. Choctawhatchee Marl. 11999 Bertie County, North Carolina: right bank of Cho- wan River, 0.75 mile (1.2 km) below Mt. Gould Landing, from bed exposed from beach to 10 feet (3 m) above river beach. W.C. Mansfield, collector, 1929. Yorktown Formation. 23468 Middlesex County, Virginia: collected along beach of Rappahannock River from Urbanna to fish NUMBER 61 79 cannery. T.G. Gibson, D. Wilson, and R. Brody, collectors, 1963. Float material mixed with Hol- ocene material, but most is Miocene, which has 25746 weathered from bluffs. 23565 Anne Arundel County, Maryland: Paul Basford Farm, on north side of Maiyland Highway 424, about 1.2 miles (1.9 km) SE of Davidsonville. D. Wilson and H. Vokes, collectors, ca. 1958. Cal- vert Formation. 25338 Beaufort County, North Carolina: Lee Creek 25747 Mine, near Aurora. Spoil banks, west of access road to central part of pit. T. Gibson, collector, August 1972. Pungo River and Yorktown for- mations. 25339 Beaufort County, North Carolina: Lee Creek Mine, near Aurora. Float from spoil piles. D. Wilson and others, collectors, 1969-1973. 25748 Pungo River and Yorktown formations. 25344 Calvert County, Maryland: 1.5 miles (2.4 km) south of Plum Point. Charles Buddenhagen, collector, 1965. Calvert Formation, bed 10. 25749 25345 Calvert County, Maryland: 0.5 miles (0.8 km) be- low Camp Roosevelt. Thor Hansen, collector, 1969. Calvert Formation, bed 10. 25743 25744 25364 Beaufort County, North Carolina: Lee Creek 25757 Mine, on the right bank of the Pamlico River, 5.5 miles (8.8 km) north of Aurora; section on northwest wall of main pit, in 5 foot (1.5 m) thick bed of gray sand, 16 feet (4.9 m) below the 25758 top ofthe pit. L.W. Ward and others, collectors, February 1972. Yorktown Formation, upper shell bed. Beaufort County, North Carolina: Lee Creek Mine. Jack McLellan, collector, 1970s. Spoil piles. Pungo River and Yorktown formations. Anne Arundel County, Maryland: Paul Basford Farm, on north side of Maryland Highway 424, about 1.2 miles (1.9 km) SE of Davidsonville; in small stream gully NW of tobacco barn. T. Gib- 2244 son and others, collectors, July, 1968. Calvert Formation. 25745 Wakulla County, Florida: Taff Pit, south of Craw- fordville. Muriel Hunter, collector, ca. 1970. Torreya Formation. Beaufort County, North Carolina: Lee Creek Mine, near Aurora, from northwest wall of test pit, 2 foot (0.6 m) bed of blue sand, 11 feet (3.4 m) above base of Yorktown Formation, under- lain by channeled surface. T. Gibson, collector, January 1964. Yorktown Formation (unit 3 of Gibson, 1967). Northampton County, North Carolina: bluff on right bank of Meherrin River about 3 miles (4.8 km) above the Highway 258 Bridge; sample taken in interval of blue clayey sand, 1 to 5 feet (0.3 to 1.5 m) above water level. T. Gibson and D. Wilson, collectors. May 1963. Lowermost part of Yorktown Formation. Beaufort County, North Carolina: shell fragments from limey layers, spoil piles, Lee Creek Mine, near Aurora. Jack McLellan, collector, April 1974. Pungo River Formation. Beaufort County, North Carolina: Lee Creek Mine, near Aurora. Jack McLellan, collector, April 1974. Uppermost part of Pungo River Formation. Beaufort County, North Carolina: Lee Creek Mine, near Aurora, Lot 211. Jack McLellan, collector, 1970s. Upper calcareous layers of Pungo River Formation. Bertie County, North Carolina: bluff on west side of Chowan River, about 0.5 mile (0.8 km) below Mt. Gould Landing, at W.H. Fowler place (old Steele place), 3-5 feet (0.19-1.5 m) above beach. T. Gibson and D. Wilson, collectors, 1963. York- town Formation. USFC STATION Western North Atlantic Ocean, SE of Long Island, U.S.A., 40°05'15" N, 70°23'00" W, 67 fathoms (121 m), green mud and sand, bottom temperature, 52.9° Literature Cited Akers, W.H. 1972. Planktonic Foraminifera and Biostratigraphy of Some Neogene Formations, Northern Florida and Atlantic Coastal Plain. Tulane Studies in Geology and Paleontology, 9(1-4): 1-139, plates 1-60. Banks, J.E., and M.E. Hunter 1973. 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Harbison 1953. Pliocene Mollusca of Southern Florida with Special Reference to Those from North Saint Petersburg. Academy of Natural Sciences of Philadelphia Monograph, 8: 457 pages, 65 plates. Puri, H.S., and R.O. Vernon 1964. Summary of the Geology of Florida and a Guidebook to the Classic Exposures. Florida Geological Survey Special Publication, 5 (revised): 312 pages, 11 plates. Richards, H.G. 1950. Geology ofthe Coastal Plain of North Carolina. American Philo- sophical Society Transactions, new series, 40: 83 pages. 1968. Catalogue of Invertebrate Fossil Types at the Academy of Nat- ural Sciences of Philadelphia. Academy of Natural Sciences of Philadelphia Special Publication, 8: 222 pages. Richards, H.G., and A. Harbison 1942. Miocene Invertebrate Fauna of New Jersey. Proceedings of Acad- emy of Natural Sciences of Philadelphia, 94:167-250, plates 7-22, 9 figures, 1 table. Roding, P.F. 1798. Museum Boltenianum sive Catalogus cimeliorum e tribus regnis na- turae quae olim colleger at J oa. Fried. Bolten, M.D.p.d., Pars Secunda, Conchylia. viii -1-119 pages. Hamburg: Typisjohan Christi Trapii. Rowland, H.L See Tucker-Rowland, H.L Say, T. 1824. An Account of Some of the Fossil Shells of Maryland. Academy of Natural Sciences of Philadelphia Journal, 4:124-155, plates 7-13. Schoonover, L.M. 1941. A Stratigraphic Study of the Mollusks of the Calvert and Chop- tank Formations of Southern Maryland. Bulletins of American Paleontology, 25(94B): 165-298, plates 19-30. Shattuck, G.B. 1904. Geological and Paleontological Relations, with a Review of Ear- lier Investigations. Maryland Geological Survey, Miocene, pages xxxiii-cxxxvii. Tucker, H.I. See Tucker-Rowland, H.L Tucker-Rowland, H.I. 1934. Some Atlantic Coast Tertiary Pectiniade. American Midland Nat- uralist, 15:612-621. [As H.l. Tucker.] 1936a. The Atlantic and Gulf Coast Tertiary Pectiniade ofthe United States. American Midland Naturalist, I7(2):47l-490, plates 1-4. [As H.l. Tucker.] 1936b. The Atlantic and Gulf Coast Tertiary Pectinidae ofthe United States -II. American Midland Naturalist, 17(6):985-1017, plates 5-10. [As H.I. Rowland.] 1938. The Atlantic and Gulf Coast Tertiary Pectinidae of the United States. Memoires du Musee Royal D'Histoire Naturelle de Belgique, 10th series, 13:1-76, plates 1-6. Tuomey, M., and F. S. Holmes 1855. Pteiocene Fossils of South Carolina. . . .Part 1, 30 pages. Charleston, South Carolina: Russell and Jones. Waller, T.R. 1969. The Evolution of the Argopecten gibbus Slock (Mollusca: Bivalvia), with Emphasis on the Tertiary and Quaternary Species of Eastern North America, yourna/ of Paleontology, Memoir, 3: 125 pages, 8 plates. Ward, L.W., and B.W. Blackwelder 1975. Chesapecten, a New Genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of Eastern North America. U.S. Geo- logical Survey Professional Paper, 861: 24 pages, 7 plates, 2 figures, 2 tables. Whitfield, R.P. 1894. Mollusca and Crustacea of the Miocene Formations of New Jersey. U.S. Geological Survey, Monographs, 24:13-193, plates 1- 24. 82 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY vy - ■ ■ \ f. *■■ r- * "i •I. f / ^^ ^/. "■'' J -'.^ PLATE 1 Pecten mclellani, new species, Pungo River Formation, Lee Creek Mine, USGS 25743 1. Paratype, USNM 218828, external view of right valve, X 1.5. 2. Paratype, USNM 218829, external view of right valve, X 1. 3. Holotype, USNM 218830, external view of right valve, X 1. 1. NUMBER 61 83 ^ y V, y PLATE 2 Pecten mclellani, new species, Pungo River Formation, Lee Creek Mine, USGS 25743 1, 2. Paratype, USNM 218831, external and internal views of left valve, X 1. 3. Holotype, USNM 218830, internal view of right valve, X 1. IM.AI K ■.\ I. Pecten humphreysii woolmani lleil|)riri, Kirkwood loi IIMIIDII. JCIKIIO, New |crsc\, ILSNM 2188S2 IISGS 2106, exiernal view ol p.irii.il liglil v.ilvc. X I. .', 1, 7 I'ldcn humphreysii humphreysii (iom.id, C.ilvtii Forin.iiioii, l),i\ idsoin illc, Maiyl.uid: 2 U.SNM L'lHHlVS, llS(;S23r>6.''), fxtcni.il \ icw of ri^lil v.ilvc, X 1;4. USNM 'JIKHH5, U.S(;S 2.^)744, c-xtenial \uw ol |).IMMI ii|;lii v.iUc. X I; 7. USNM 2IKK:iK, L:S(;,S 2:V'>(ir), rxiirii.il view ol nj^lii v.iKc, X I. 3. .'), (). Pi'i liH hij>nphri'\Mi humphreysii (iom.id, I'migo Ri\ci lot IT i.i I ion. I.ci' ( jtik Mine: 3, ll.SNM 2 1 HH34 I .S(,,S 2,'):VV,), cxUMi.il view ol paili.il riglil v.ilvc, X 1; '>, llSNM L'lHKI^fi, t).S(;S 2.'>743, external \i( w ol ii^iii v.ilvc, X 2; 6. USNM 218837, liS(;S 2,''>H3'.I, cxicm.il view ot partial right valve, X I. PLAIK 4 -3. 7. Pecten humphreysii humphreysii (Conrad, Pungo Rivci Forniation. Lcc Creek Mine, cxlcni.il view of partial lefi valve: 1, USNM 2I8H39. U.S(;S 25339, X I; 2, USNM 218840, US(;S 253:^9, X 1; 3. USNM 218841, U.SC;S 25339. X 1; 7, USNM 218845, U.SGS 25339. X 1. 4-6. Pecten humphreysii humphreysii Conrad, Torreya Formation, Oawfordville. Florida, USG.S 25745: 4. USNM 218842. external view of partial right valve. X 1; 5, USNM 218843, external view of partial right valve, X 1.5; 6, USNM 218844, external view ot parii.il lefi valve, X 1. (From Banks and Hunter. 1973.) 8. Pecten humphreysii humphreysii Coiir.id, C.iKert Formation, Da\ idsoiiviJk-. M.irviaiul, USNM 218838, US(;S 2356.'), internal view of right valve, X 1. 86 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 5 1, 2, 4. Pecten humphreysii humphreysii Conrad, Calvert Formation, Davidsonville, Maryland, left valve: 1, USNM 218846, USGS 25744, external view, X 1.5; 2, USNM 218846, USGS 25744, internal view, X 1.5; 4, USNM 218838, USGS 23565, external view, X 1. 3. Pecten humphreysii woolmani Heilprin, Kirkwood Formation, Jericho, New Jersey, USNM 218847, USGS 2106, external view of left valve, X 2 (see also, Whitfield, 1894, pl. 4: fig. 7). PLATE 6 1-4. 6. Pecten humphreysii woolmani Heilprin. Kirkwood Foriii.ition. Jeric lio. New Jersev. L'StiS 2106: 1, USNM 218848, external view of right valve. X 1; 2. 3. USXM 218849. external and internal views of lefi valve. X 1 (.see also Whitfield. 1894. pl. 4: figs. 8.9); 4. USNM 218850, external view of partial right valve, X 1; 6, USNM 218848, resilial inseition of right valve, X 3. 5. Pecten humphreysii humphreysii Conrad. Pungo River Formation, Lee Oeek Mine, t .SNM 21M,S,'i|, L SGS 23339, external view of partial right valve, X I. 7. Pecten humphreysii humphreysii Conrad. (Calvert Formation, Davidsonville, Mai \ land, LSNM 218H38, t S(;S 23."i6.'i, internal view of lefi valve, X 1. SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY 5 ^i.i4 Pl.AI K 7 Argopecten eboreus .ill. A. clwrcus watsonensis (M.insficid), ^'oiktowii Formation, l.cc (^nck Mine 1. tISNM 218852. U.StiS 25746, external view ol right valve, X 1. 2. tlSNM 218853, U.SCiS 25338, external view of right valve, X 1, 3-.'). USNM 21KH54, LISGS 2,')7 Hi, right valve: 3, rcsili.il insertion, X 3; 4, external view, X 1; 5, internal view, X I. 6. USNM 2IKH5.'i, tISGS 2.'')74(), right valve, icsiii.il insertion, X 3. NUMBER 61 89 IHg^yL^^ju^^MpHlIF',' jHL^||MM|^^ygyttiijj|A|iHp^^. PLATE 8 Argopecten eboreus aff. A. eboreus watsonensis (Mansfield). Yorktown Formation. Lee Oeek Mine. tISCiS 2."i746 1. 3. USNM 218856, lefi valve: 1. external view X 1; 3, internal view. X 1. 2. 4, 6. tISNM 218857, lefi valve: 2, resilial insertion. X 3; 4, external view. X 1; 6. internal view, X 1. 5. tlSNM 218858, external view of right valve, X 1. 90 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 9 1, 4. Argopecten eboreus darlingtonensis (Dall), Duplin Formation, Darlington, South Carolina, USGS 2025: 1, lectotype, USNM 145432, external view of anterior portion of right valve, X 2; 4, lectoparatype, USNM 218859, external view of lefi valve, X 1. 2, 3. Argopecten eboreus aff. A. eboreus solarioides (Heilprin), Yorktown Formation, Lee Creek Mine, USNM 218860, USGS 25339: 2, external view of right valve, X 1; 3, external view of left valve, X 1. 5. Argopecten eboreus yorkensis (Conrad), Yorktown Formation, Yorktown, Virginia, lectotype, ANSP 38007, external view of left valve, X 1. NUMBER 61 91 PLATE 10 1-3. Argopecten eboreus aff. A. eboreus solarioides (Heilprin). \'orktowii Formation. Lee Creek Mine. I S\M 218860, US(;S 25339, right valve: 1, resilial insertion, X 3; 2, internal view, X 1; 3, external view of anteiior ventral part, X 4. 4. Argopecten eboreus aff. A. eboreus watsonensis (Mansfield), ^■orktowll Forin.ition. Lee Creek Mine, t SNM 21 8861. L:S(;S 2.I33H. dorsal view of articulated speciiiien, X 1. 92 SMITHSONIAN CON IRIBU IIONS TO PALEOBIOLOGY ////mm IMA I F I I 1. 3, I. Ar^djiedin ehuiiiis inlnnniuensis (M.iiislicld), An gnu.i Si M.iiss" beds, I i b.iiiii.i, X'ligiiii.i, I S( ;S :VH 'y I , l((ioi\|)( . I SWI 37()H29, exteiiial view ol tight \.il\c, X I ; 3. lc(totvi)c, tiSNM 37().S29, icsiii.il inscitioii, X ;'.; t, le( t<>|),ii at y|)e, IISNM 21HH()2, icsili.ii iiisci I ion of kfi v.ilvc, X 3. 2, ."). Aigope/len elnneus .iff. ,1. eboreus solanni/les (Heilprin), N'oiktown l-Oi iii.il ion, l.cc Creek Mine: 2. I SWI L'IKMdl). I S(.S 2.'>3;'i'l. (lois.ii view of articulated specimen, X I; 5, tiSNM 203904, US(;S 2,')3(> 1, (Atci ii.il Mcu of I iglii v.iKc, X I NUMBER 61 93 PLATE 12 1. 3. 5. Placopecten magellanicus (Gmelin). Recent, south of Long Island. 67 fathoms. L'.SFC^ 2244: 1. USNM 703766-161., lesilium, X 3; 3, USNM 703766-21 R, external view of right valve. X 1; ,'), LSNM 7(»37(i6-l6R, external view of right valve, X 1. 2, 4. Placopecten clintonius clintonius (.Sav), \'orktowii Formation, Lcc (Ircck Mine, L .S(iS 2,"533X. external view of light valve: 2, L S\M 21S8(i3, X 1; 4, I SWI 2I.SS64, X 1. 94 SMIIHSONIAN CONIRIBUnONS IO PALEOBIOLOGY IMA IF 13 ],'.'>. I'liKiiperleii 11 in Inn i us t linlnnnis (S.n ) (= /' i tin Ian i us tl una hi I ( I ii< kcl -Row l.iiul)), ^■()l klow ii Idi iii.il ion, (.io\( Uh.iil, \ II gun.I. li..loi\|.( ol /' f. donaldi. I SWI 1 14996, tlSt.S 2 1.")2: I, exteni.il om.iincii- 1,11 ion on .iiiK I loi \( nli.il p.iil ol \.iKc, X :'.; :'., cxtelli.il view of left v.iKc, X I . 2 I'eilen wilelltnii. IK u s|)C( ics, Pungo Kl\ci Fol lli.nioii, Lee ('.Ici-k Mlli<-, |).il .it \ ])c. I SWI 2IHH().'), t S(.S '..''iT t;'>. , (lois.il MCU of .iilKul.itcd spcdiiicii, X I. 3. (. Fxtciii.il vicu ol lell v.iKc, X I: 3, ISWI 2IH!)01;(i, I SNM 21H903. C.hesaperlen jeffersonius septenarius (.Say), Yorktown FOrmation, Lee (^reek Mine, U.Sti.S 25338 7, H. Kxtcrnal view of left valve, X I: 7, USNM 218906; 8, USNM 218907. PLA IK 22 1. Chesapecten madisonius (S. Intel 11,11 MCU , X I ; I, cxtei ii.il \ lew, X I . 3, () .\inusiiim preiursiir (l).ill), (Jiipol.i lot iii.ition, B.iileys Fcii\, Floiid.i, I SWI 2IK93I, USti.S 2''l'' li.igiiiciil ol \.il\c: 3,cxlcin.il view, X I; (i, intern.il view, X I. 7 (lliesapecleii nefrens VV'.ii d .ind lil.u kwcldci, Pungo River FOnii.ition. Lcc- (aeck Mine, LI .SNM 2 I K^)32 US(,S 237 10, extern.il view ol right valve, X 1. Late Pliocene and Early Pleistocene Mollusca from the James City and Chowan River Formations at the Lee Creek Mine Lauck W. Ward and Blake W. Blackwelder ABSTRACT A molluscan fauna consisting of 194 species is described from the Chowan River (upper Pliocene) and James City (lower Pleistocene) formations at the Lee Creek Mine, Au- rora, North Carolina. These two formations are as much as 7 ni thick in the mine and unconformably overlie strata that correlate with the Yorktown Formation in its type area. The Chowan River and James City formations are separated by an unconformity. The mollusks of the Chowan River Formation are assigned to the Glycymeris hummi—Turritella perexilis assemblage-zone and the mollusks in the overlying James City Formation are assigned to the Marvacrassatella hauffmani-Astarte berryi assemblage-zone. Although mol- lusks in these zones lived in a subtropical thermal regime, they include some warm-temperate species not found in contemporaneous deposits farther south. The units repre- sented by these assemblage zones were deposited mostly under open marine conditions at a maximum depth of about 25 m. The Marvacrassatella kauffmani-Astarte berryi assem- blage at Lee Creek lived in association with an offshore bar system, which has some large unidirectional current-bedded shelly sands. Although more than 65 percent of the species in the assemblages are now extinct, the composition and diversity ofthe mollusks in the different beds is very similar to that ofthe Argopecten gibbus community presently living off the North Carolina coast. Introduction Open-pit mining for phosphate by Texasgulf Inc. at Lee Creek, near Aurora, Beaufort County, North Carolina (Fig- ure 1), has provided excellent exposures ofthe Pungo River Formation (lower and middle Miocene), the Yorktown For- mation (lower Pliocene), the Chowan River Formation (up- per Pliocene), and the James City Formation (lower Pleis- tocene). The James City Formation at the mine is very Lauck W. Ward, United States Geological Survey, 970 National Center, Reston, Virginia 22092. Blake W. Blackwelder, Tenneco Building, J-2114B, Box 2511, Houston, Texas 77001. macTofossiliferous and represents about the northernmost known locality for such richly fossiiiferous lower Pleistocene beds. Because of the paleogeographic importance of this locality, the molluscan fauna ofthe Chowan River and James City formations is documented in formal systematics in this paper, and the stratigraphy, biostratigraphy, and paleoecol- ogy of the beds is discussed. Collections at the pit were made on 14 and 15 February 1972 with Druid Wilson, Thor Hansen, and Gordon Law- rence. Additional collecting was done on 25 and 26 April 1972, 14 June 1972, and on 4 May 1973. Other localities of similar age have also been studied and collections made between the Neuse River and the Chowan River, North Carolina. This paper was submitted to the volume editor on 3 March 1975. Some updating ofthe paper has been done since that time but not all recent references have been included. ACKNOWLEDGMENTS.—Texasgulf Inc. generously pro- vided access to the phosphate pit. Collection of mollusks was aided by Jack McLellan, then of Texasgulf, now Austin, Texas, by G.B. Lawrence, Richmond, Virginia, and by Thor Hansen, University of Texas at Austin. Lyle Camp- bell, University of South Carolina at Spartanburg, and Druid Wilson, National Museum of Natural History, pro- vided assistance in various parts of this project. Joseph E. Hazel, then U.S. Geological Survey, Reston, and Norman F. Sohl, U.S. Geological Survey, Washington, made sub- stantial contributions to the content of this paper. Walter R. Brown and Mary J. Mann, National Museum of Natural History, took the SEM photographs. Several other photo- graphs were taken by Robert H. McKinney and Haruo E. Mochizuki, U.S. Geological Survey, Washington. Jules R. DuBar, then Morehead State University, and Thomas R. Waller and F.A. Ruhoff, National Museum of Natural His- tory, provided advice and assistance during the study. Stratigraphic Setting GENERAL.—Approximately 21 m of beds thought to be of Pliocene and early Pleistocene age (Hazel, 197la: 10; 113 114 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY KILOMETERS FIGURE 1.—Location ofthe Lee Creek Mine on the Pamlico River, North Carolina. The corner inset .shows the study area on a regional map. Akers, 1972:134) unconformably overlie the Pungo River Formation (lower and iniddle Miocene) at the mine (Gibson, 1967:634). The lower 14 m belong to the Yorktown For- mation and consist of sparsely macrofossiliferous (except for certain beds in the lower 3 m) sandy clays and clayey sands. These beds are unconformably overlain by 7 m of richly macrofossiliferous upper Pliocene and lower Pleisto- cene sands and clayey sands. These 7 m of section are the basis of this study. On the basis of mollusks, ostracodes, and foraminifers, the beds assigned to the Yorktown Formation at the mine can be correlated with the Yorktown Formation in its type area. The Chowan River Formation is separated from the Yorktown by a regionally significant unconformity and represents a separate important geologic event. CHOWAN RIVER FORMATION.—Deposits along the Cho- wan River, northeastern North Carolina, have long been assigned to the uppermost part of the Yorktown Formation (Clark et al., 1912; Mansfield, 1944). More recently, Hazel (1971a; 1977) recognized that the Chowan River beds are younger than most Yorktown beds in the type area at Yorktown, Virginia. Ward and Blackwelder (1980) rede- fined the Yorktown Formation and recognized that the "Chowan River beds" unconformably overlie the Yorktown Formation. Blackwelder (1981) named the Chowan River Formation for the "Chowan River beds' and correlated the formation with the Bear Bluff Formation in South Carolina. Bailey (1977) discussed molluscan biofacies in these depos- its. In Virginia, Oaks et al. (1974) discussed a barrier and lagoonal deposit, informally termed the "Moorings unit," which formed when sea level was at 36-37 m (120-125 ft). They indicated that substantial erosion followed the depo- sition of the "Moorings unit." Oaks and DuBar (1974) correlated the Bear Bluff Formation of South Carolina with the "Moorings unit." "Moorings" apparently represents the shoreline deposits of the Chowan River Formation. JAMES CITY FORMATION.—To the south of the Chowan River area, Mansfield (1943) considered the "Croatan Sand" on the lower Neuse River stratigraphically higher than the "Chowan River beds." DuBar and Solliday (1963:214) pro- posed that the name "Croatan Formation" be abandoned because it had been used for two very different and unre- lated lithic units. They named these units the James City Formation (now known to be of early Pleistocene age) and Flanner Beach Fonnation (of late Pleistocene age). Prior to the DuBar and Solliday (1963) paper, Mansfield (1936:668) suggested that the Croatan be restricted to the older of the two deposits. These attempts to restrict the use of the term "Croatan" to the older beds have not been based on lithic criteria. Mansfield suggested that the beds at James City might be considered the type section. However, this locality below James City was not even mentioned by Dall, whose type sections were rather remote from James City and adjacent New Bern. Dall (1892:209) had proposed the name "Croatan beds" for units along the Neuse River at Slocum's Creek and at Mallison's. The Slocum's Creek locality was stated to be "fifteen miles [24.1 3 km] below New Bern" and the Mallison's locality "thirteen miles [20.91 km] below New Bern." At these localities, late Pleistocene age material is prominent and early Pleistocene age beds are poorly ex- posed. For these reasons Blackwelder (1981) recommended that the term Croatan be abandoned. The Windsor Formation in Virginia was named by Coch (1968) for beach, nearshore, and lagoonal coarse sands, pebble gravel, and silty clay and sands that formed when sea level stood at 24.4-30.2 m (80-100 ft). Coch's Windsor is correlated with the Waccamaw Formation by Oaks and DuBar (1974:73) and is found to the east ofthe Surry Scarp in Virginia. The Windsor represents marginal marine de- posits correlative with the James City Formation. Black- NUMBER 61 115 welder (1981) discussed the distribution of the James City Formation and its relationship to the Chowan River For- mation. The James City Formation has also been correlated with the Waccamaw Formation in North and South Carolina and with the upper part of the Caloosahatchee Formation in Florida on the basis of the fossils (DuBar, Solliday, and Howard, 1974). Five He/U dates on corals from the Ca- loosahatchee Formation in the type area range from 1.78 to 1.98 million years (m.y.) with an average of 1.84 m.y. (Bender, 1973). A sample from beds, which have been assigned to the Caloosahatchee Formation at St. Petersburg, Florida, was dated by Bender at 2.53 m.y. The Pliocene- Pleistocene boundary is placed at about 1.8 m.y. (Berggren and Van Couvering, 1974). The Chowan River Formation (unit B at Lee Creek, see below) may be approximately equivalent to the lower part of the Caloosahatchee at St. Petersburg (upper Pliocene) and the James City Formation at Lee Creek may be the equivalent of the type Caloosa- hatchee (lower Pleistocene). STRATIGRAPHY OF THE CHOWAN RIVER AND JAMES CITY FORMATIONS AT THE LEE CREEK MINE.—Figure 1 shows the location of the mine on the Pamlico River. The mine area is large, and the walls of the pit as they existed in April of 1972 are shown in Figure 2. The original shoreline of the Pamlico River at Lee Creek has been changed. In Figure 2, the original location of Lee Creek and the old Pamlico River shoreline are represented by a thin dashed line, and a solid line represents the new shoreline. The location of the walls of the phosphate pit is shown by a heavy dashed line. The locations of six measured sections made in the pit are indicated by numbered circles. The section studied by Gibson (1967) was from a test pit between our first and second sections and in the area of the old Lee Creek channel. A fence diagram of the measured sections indicated in Figure 2 is shown in Figure 3. Sea level is approximately 4.5 m below the land surface. Unit A (Yorktown Formation) is an olive-gray clayey fine sand containing abundant micro- fossils, a lithology that typifies much ofthe Yorktown from this unit down to the top of the Pungo River Formation at the pit (~14 m). This 14 m section contains beds that belong to the Pterygocythereis inexpectata and Orionina vaughani assemblage-zones of Hazel (1971a). Unit A is separated from unit B (Chowan River Formation) by an unconformity. Unit B is an olive-gray coarse sand, bedded, burrowed, Garrison Point ADVANCE J-, locationf /PIT OPEN Approx. of long wall I April 1972 >| . <2X„\:^ ^Miie 1 Kilometer ~^\ <}>-'' FIGURE 2.—Original location of Lee Creek and ofthe old Pamlico River shoreline in relation to the walls ofthe Lee Creek Mine. Location ofthe measured sections in the walls ofthe mine is indicated by numbered circles. 116 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY G '^/^f---. F ^^- E -%^'- r> fl o I C cf^e- A»i UNIT meters feet 3.65-rl2 2.43-- 1.21-4 o-'-o Tan to orange fine sand Cross bedded =-\ Dark olive gray (5Y3/1) fine sandy clay, burrowed, with wood stumps at top surface Light gray (N7) clayey medium fine sand with fine shell hash Light gray (N7) coarse to fine sand Very large molluscs abundant High angle current bedded alternating sand-shell layers Greenish gray (5GY6/1) iron stained clay fine sand. Large molluscs abvindant Olive gray (5Y4/1) coarse sand, bedded, Burrowed, mottled, partly indurated with differential leaching. Fine shell in unleached portion. Olive gray (5Y4/1) clayey fine sand. Microfossils. covered YORKTOWN FORMATION FIGURE 3.—Fence diagram of measured sections. Locations of measured sections are shown in Figure 2. U.S. Geological Survey numbers are given for the particular units from which samples of mollusks were taken. mottled, and partly leached. Many small-shelled mollusk species arc found in the unleached parts. Unit B is overlain by units C-E, assigned to the James City Formation. In the northern part of the pit a greenish gray iron-stained clayey fine sand containing abundant large mollusks (unit C) fills an extensive cut in the top of unit B. Over these units, a light gray sand was deposited (unit D), which varies from fine to coarse and contains extremely abundant mollusks. On the north wall of the pit, this unit was deposited as unidirectional high-angle current-bedded, very shellly sand containing occasional pockets of almost pure shell and olher pockets of pure sand. Elsewhere in the pit, this unit is horizontally bedded. Unit D is succeeded by a light gray, horizontally bedded, clayey, medium fine sand containing abundant small shells (unit E). On the south wall, unit E has been extensively NUMBER 61 1 1 FititRKS 4-7.— I he south wall of the pit showing unit .A. succeeded b\ the ledg\ indurated sandstone (unit B). follcjwed l)\ \er\ shelh units D and E. T he channels cut into shell beds, and the fillings b\ unit F are visible. The light siinds at the top of the section are unit G. Figure 4 shows a channel cutting into sht-ll beds D and E. and the sharp contact between beds V and G. Figure 5 is a \iew of this south wall looking to the west and showing continuous indurated ledges in unit B. Figure 6 is a closer view of this wall showing the uiuonformable c§iuu a. Northeastern North Carolina South Carolina South Florida Mollusk Zone Ostracode Assemblage-zone 0- uncJividid ~ "undivided" ~ undlv"i3eci~~ 1 1 BRUNHES N22 PLEISTOCENE EARLY 1 LATE 1 FLANNER BEACH TinimjTininim SOCASTEE mmmmmmirT FT, THOMPSON m m m mm mi n undivided CANEPATCH BERMONT CAI nnRAHATCHFF 1 < < > 1- < JAMES CITY WACCAMAW upper Marvacrassatella kauffmani- Astarte berryi Assemblage-zone Puriana mesacostalis z o z z "CO z PLIOCENE EARLY 1 LATE iiiiiiiniiiiiiiiiii lllllllllllllllllllll iiiiiiiiiniiii lllllllllllllllllllllll 1 CHOWAN RIVER BEAR BLUFF lower Glycymeris hummi- Turritella perexilis Assem blaae-2one 1 I GAUSS ' 4- 5- YORKTOWN upper 'IT^ RAYSOR YORKTOWN^- TAMIAMI Chesapecten madisonius Range-zone Orionina vaughani GILBERT II lower iliilllll Chesapecten Jefferson- ius Assemblaqe-zone Pterygocythereis inexpectata III lllllllllllllll MUMLIl^m, iiiiiiiiiiiiiiiniiiiiii Illlllllllllll FIGURE 12.—Biostratigraphic correlation ofthe Yorktown, Chowan River, anci James City formations at Lee Creek. Stratigraphic positions of other associated deposits in South Carolina and Florida are indicated. The stratigraphic range of some iinportant taxa is also shown. crassatella kauffmani succeeds Marvacrassatella undulata, which is found in zone 2 of the Yorktown. For this reason, M. kauffmani is a guide to the upper Pliocene in this part of the Coastal Plain. Marvacrassatella kauffmani and Astarte berryi both occur in the Glycymeris hummi and Turritella perexilis assemblage-zone, but G. hummi does not range into this younger assemblage. Both of these assemblage-zones may be impcjrtant in recognizing subsurface units in this part of North (Carolina. Paleoenvironmental Reconstruction FAUNAL COMPARI.SON OF UNITS B THROUGH E.—The stratigraphic occurrence cjf different species cjf mcjilusks is documented in Table 1. Occurrences are shown by an "X" and the sections and units refer t^o those on the fence diagram (Figure ,S). To facilitate quick reference between Table 1 and the systematic section, the list is alphabetized by genus and seccjndarily by species. Table I shows that many species range through the whole section in different parts of the pit. I his distribution of the species refiects the fact that these shell beds were deposited under essentially similar hydrographic conditions cm the shallow shelf at a water depth of at least 15 m, most of the beds probably being at a depth of 20 m or slightly greater (see "Argopecten gibbus Community," p. 124). The most important species having a limited range (because of evolution or extinction) within these beds is Glycymeris hummi (p. 138). Table 1 has some bias, in that the mollusks contained in the units of section 5 were studied in more detail than were those of other sections. Other sections were examined for composition and relative abundance of species, but samples were never entirely picked or sorted. For this reason, data from section 5 are more nearly complete than those from the other sections. Because ofthe small number of samples involved and because of this bias in examination, multivar- iate methods were not used to analyze the data. The ar- rangement by stratigraphic unit of samples in Table 1 permits an easy visual analysis of the stratigraphic occur- rence of species. Abundances of species are probably more diagnostic of the dirferenl stratigraphic units, but abun- dances change in the same unit in different sections of the pit f)ecause topographic and hydrographic conditions were not everywhere the same during deposition. The spatial arrangement of certain species abundances is given in Fig- ure 13 and in a later section on the chronology of events. Individual species abundances are mentioned in the system- atic section. Becau.se ofthe close similarity in species com- TABLE 1.—Species occurrences in measured sections of the Chowan River (unit B) and James City (units C, D, E) formations al Lee Creek Mine (sections designated by number, units by letter, x = present, dash = not found, =^ = collected as float from LISGS 25339) Species 1 2 Class PELECYPODA Abra aequalis (Say) Aligena striata Lea Anadara aequicostata (Conrad) Anisodonta Carolina Dall Anomia simplex d'Orbigny Argopecten vicenarius vicenarius (Conrad) Astarte berryi Gardner Astarte concentrica Conrad Bellucina waccamawensis (Dall) Bornia triangula Dall Brachidontes sp. Callucina kenae (Chavan) Carditamera arata (Conrad) Carolinapecten eboreus (Conrad) Caryocorbula auroraensis, new name Caryocorbula contractu (Say) Cavilinga trisulcata (Conrad) Chama gardnerae Olsson and Harbison Chione cribraria (Conrad)* Chione grus (Holmes) Cochlodesma emmonsii, new species Conradostrea lawrencei, new species Corbicula densata (Conrad) Crassinella dupliniana (Dall) Crassinella johnsoni, new species Crassinella lunulata (Conrad) Grassostea virginica auroraensis new subspecies Crenella decussata (Montagu) Cumingia tellionoides (Conrad) Cyclocardia sp. cf. C. granulata (Say) Crylopleura sp. Dinocardium robustum hazeli new subspecies Diplodonta acclinis (Conrad) Diplodonta berryi McGavock Divalinga sp. Donax fossor Say Dosinia sp. Ensis directus (Conrad) Fnsitellops elongata Olsson and Harbison Erycinella ovalis Conrad Gastrochaena hians (Gmelin) Gemma magna majorina Gardner Glycymeris americana (Defrance) Glycymeris arata (Conrad) Glycymeris hummi, new species Glycymeris sloani, new species Gouldia metastriatum (Conrad) Laevicardium sublineatum (Conrad) Leptopecten} auroraensis, new species Lithophaga yorkensis Olsson Macoma holmsii Dall Macrocallista greeni, new species Marvacrassatella kauffmani, new species Mercenaria mercenaria (Linnaeus) Mercenaria permagna (Conrad) Modiolus sp. cf. M. modiolus (Linnaeus) Mulinia lateralis (Say) Musculus lateralis (Say) Mya arenaria Linnaeus Mysella baufortensis, new species Mytilus sp. Noetia limula (Conrad) Nucula pilkeyi, new species Nucula proxima Say Nucula taphria Dall X - X X - - X X X - X X - X X - - - - - X - - - - X X X X X X X X X - X X X X X X - X X - - - - - - - - - X X - X X X X X - - - - - - - X - X - - - - X - X X X X X X X X - X - X X X X X X X X X X X X X X X - - - X - - X X - X X - X X X - - X - - - - X X - X X X - X X X X X X X - X - - X X X X X X X X X X X X X X X X X X X X X X X X X - - X X - - - X - - - X - X X X - - X X X - X - - - X ~ ~ - X X X X 1 X X X X X X X X X - X X - X X X - - - - - - X X - - - X X X X X X - - X X - - X X - - X X - - X - - - X - - X X X X X X X X X X - X X - - X - X X X - - - - X X X - - X - X - X - - - X X - - X - X X - X X X X X X X X X X X X X X X X X X X X X X X - X X X X - - X - - - - X - X - - X - X - X X X X X - X X X - - - - - - - - X X X X _ - X X X X _ X X - X X X - - - - X - - - - - - - X - - - X X X - - X X X X X X - X - X X X - - X X X - - X X X X - - X X X - - X X X X X X X _ X X _ _ _ X X X X X X X X X X X X X X X X - X - X - - - X - X - - - X - X X X X - - - X X - - X X - X X X X X - X - - X - X - - X X X X X X X X - - X X X _ X X X X X X X _ X X X X - X - X - X X X X - X X X - - X X - - X X X - - X - - - - - X X - - X - - - X X - X X X X X X X X - X ~ X X X X X X X X _ X X X X - - X X - - X - - - X -TABLE 1.—Continued. Species Nuculana acuta (Conrad) Pandora tuomeyi Gardner and Aldrich Panopea floridana Heilprin Paramya subovata (Conrad) Parvilucina multilineata (Tuomey and Holmes) Petricola pectorosa (Conrad) Petricola pholadiformis Lamarck* Phlyctiderma heroni, new species Pilar chioneformis (Gardner) Pleuromeris auroraensis, new species Pleuromeris decemcostata Conrad Plicatula marginata Say Pododesmus fragosus (Conrad) Pteromeris perplana (Conrad) Quadrilatera adamsi (Dall) Raeta plicateklla (Lamarck) Rangia clathrodonta (Conrad) Semele bellastriata (Conrad) Sphenia dubia (Lea) Spisula similis (Say) Spisula solidissima (Dillwyn) Sportella waccamawensis Gardner Stewartia anodonta floridana (Conrad) Tagelus plebeius caroilnensis (Conrad) Tellina agilis Stimpon Thracia brioni, new species Transennella stimpsoni Dall Verticordia emmonsii Conrad Verticordia lockei, new species Class SCAPHOPODA Cadulus quadridentatus (Dall) Class GASTROPODA Acetocina candei (d'Orbigny) Aesopus gardnerae, new species Aesopus ithitoma (Dall) Aesopus stearnsii (Tryon) Anachis milleri Gardner Arene pergemma (Gardner) Balcis beufortensis, new species Balcis biconica (Gardner) Balcis eborea (Conrad) Balcis} sp. Bittium podagrinum Dall Brachycythara reidenbachi, new species Busycon adversarius Cx)nrad see 1329 Busycon carica (Gmelin) Busycon concinnum Conrad Busycon spiralus pyruloides (.Say) Caecum beaufortensis, new species Caecum flemingi Gardner and Aldrich Caecum imbricatum Carpenter Caecum pulchellum .Stimpson Calliostoma philanlhropum pontoni Mansfield Calyptraea centralis (Conrad) Chrysallida auroraensis, new species Chrysallida beaufortensis, new species Conus adversarius Conrad (Crepidula aculeata (Gmelin) Crepidula fornicata (Linnaeu.s) (jrepidula plana Say (Crucibulum lawrencei, new species (jyclostremiscus obliquestriatus (I^ea) Cymatosyrinx lunata (Lea) Dentimargo polyspiraf (Ohson and Harbison) X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X - X _ X X X X X X X - X - X X X- X - X X X - X X X X X X X - X - - - X X X _ X _ - - X - X X - X X X X - - X - X X X X - - - X X X X X X - X _ XX X - X - X X X X X X X- X - X X - X X X X X X X - - X - - X - X X X X X X X X - X - - X X X - X X X X - X X - - X X - - X - - - X X X Xxxx - - X X X X X X - X X X X _ X X X TABLE L—Continued. 5 6 2 3 4 5 X X X - - X X - X - - X - X - - X - - 1 2 Species Didianema carolinae (Gardner) Diodora auroraensis, new sjjecies -- _ _XX- --X Diodora nucula (XiaW) XXX X- _X-X X-X Diodora pamlicoensis new species -- - _X-- --X Epitonium carolinae Gardner --X - - -X - ___ Epitonium fractum Dall -- X-- ___ ___ Epitonium leai, new species --X - - -- - --X Epitonium rupicolum (Kurtz) -- - _ _X ----X Epitonium sohli, new species __X - - -- ____ Epitonium sp. cf. E. foliaceicostum (d'Orhxgny) ___ __ _ _ ___X Eulimajuncea (Gardner) -__X-- - -- — Eupleura caudata (Say) ___ X- - -X -- X Fasciolaria beaufortensis, new species -- -- -XX --XX- Fasciolaria cronlyensis Gardner ___ __ __x - -- Glabrocythara sp. -- X----X-- -- Granulina ovuliformis (d'Orbigny) --X X- -XXX --X-X Heilprinia caloosaensis malcolmi, new subspecies* -- -- ____ __ __ Lillorina carolinensis Conrad ___ __ ___x — - -- Lunatia heros (Say) X- -- -XX- --X-- Macromphalina hanseni, new species ___ X- ____ __ __ Macromphalina pierrot Gardner ___ __ ____ X---- Mitrella gardnerae (Olsson and Harbison) ___ __ ___x ----X Mitrella gardnerae ecarinata (Olsson and Harbison) ___ __ ___x _____ Mitrella waccamawensis Gardner ___ X- --X ----X Murexiella macgintyi (M. Smith) ___ __ _X-- --X- — X X X X X X - 1 1 1 X 1 1 1 X X X - - - 1 1 1 1 1 1 1 1 X X - X X X X X X X X - - X - X X _ X X X X _ X X _ _ X X X X X X X - X X X - - X - - - - - X - - - - - - X - - - - - - - - - Nassarius chowanensis (Gardner) Nassarius cornelliana (Olsson) Nassarius granifera (Conrad) Nassarius scalaspira} (Conrad)* Nassarius schizopyga? (Dall) Odostomia simplex (Lea) Odostomia turbinatus (Lea) Oliva carolinensis (Conrad) Olivella mutica (Say) > Orinella beaufortensis, new species Polinices duplicata (Say) Prunum limatulum (Conrad) Pterorhytis conradi (Dall) Pyrigiscus daedaleum (Lea) Pyrgiscus sp. Ringicula semistriata d'Orbigny Rissoa geraea Dall _ _ - - - - - X X X X X X - X X X X X - - X X X - X - - - - - - - - - - - X X - X X - X - - - _ - - - - X X - - - _ X - - - - - - - - X - - - X - - - X X _ X - - - - X X X - - X - X X X X - - - X X X X - X X X _ X X - X - X _ _ - - X - - _ - - - X - X X - - X X X _ X X - - - - _ _ - _ - X Sedilia sp. aff. 5. sedilia (Dall) Seila adamsi (Lea) XX XX X-XX -X--X Serpulorbis granifera (Say) -XX X- -XXX - XXX Strioterebrum sp. Strioterebrum sp. cf. S. petiti Olsson ___ _ -- - - --X Tectonatica pusilla (Say) --X X — X - — --X Teinostoma beaufortensis, new species Teinostoma goniogyrus Pilsbry and McGinty ? Teinostoma smirkon Gardner Teinostoma tectispira Pilsbry Trigonostoma sp. Triphora dupliniana (Olsson) Trivia floridana Olsson and Harbison Turbonilla abrupta Bush XXX X- -X-X ---X Turritella beaufortensis, new species Turritella perexilis Conrad XXX XX -XXX --X-X Urosalpinx sp. cf. U. perrugata (Conrad) Urosalpinx stimpsoni Gardner Urosalpinx suffolkensis Gardner Vermicularia spirata (Philippi) Vexillum wandoense (Holmes) Vitricythara micromeris (Dall) Voltutifusus typus Conrad Volvarina avena (Kiener) 124 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY positions of different units, the assemblages are considered together in some of the comparisons to follow. It should be remembered that the number of species in units B and E is slightly less than that of other units, but that most of these species are also shared by other units and that the units all represent similar or related shelf environments. DEPOSITIONAL PHASES.—The upper shell beds at Lee Creek are interpreted as representing three distinct depo- sitional phases (Figure 13). The first phase (bottom) consists of a transgression and the deposition of unit B (Chowan River Formation, a shallow-shelf coarse-bedded sand de- posit) over the fine clayey sands of unit A. Unit B, which contains the Glycymeris hummi-Turritella perexilis assem- blage-zone, has subsequently been differentially leached during subaerial exposure. The second phase resulted in deposition of the James City Formation as an offshore bar system, which formed at Lee Creek following a new transgression. Unit C represents a shallower part of this depositional system, possibly depos- ited in .scoured-out parts of unit B. Unit C is followed by deposition of higher energy fine-to-coarse shelly sands (unit D) which, in the north wall of the pit, are unidirectionally current bedded (Figure 13 and Figures 9-11). In the last phase of deposition (Figure 13), finer grained sediments containing abundant small shells (unit E) were deposited in a lower energy, slightly shallower environment. Possibly an offshore barrier had built up and prevented scouring, except in certain places, such as topographic highs on the old bar deposits. COMPARISON OF FAUNA OF BEDS B THROUGH E WITH ARGOPECTEN GIBBUS COMMUNITY.—The composi- tion and diversity ofthe Chowan River and James City Lee Creek molluscan assemblages are (with the exception ofthe highest shell bed, unit E) quite similar to those of the subtropical Argopecten gibbus community reported by Porter and Wolfe (1971) living today off the North Carolina coast south of Hatteras in about 20 to 40 meters of water. This Argopecten ccjmmunity has about 82 species of pelecypods (compared with 95 for Lee Creek), 2 scaphopods (I at Lee Creek), and 94 gastropods (98 at Lee Creek). Shallower water assemblages usually have fewer species. For example, the number of species listed by Bird (1970) for shallow- marine and estuarine benthic molluscan communities from Beaufort, North Carolina, is small (57 pelecypods and 48 gastropods). Parker (1959) listed only 68 pelecypods and 53 gastropods from the bays and lagoons of the Rockport, Texas, region and the Laguna Madre. Not only do these shallow-water comnmnities have fewer species, but the ap- portionment cjf species among the different molluscan fam- ilies is quite different from that of the Lee Creek assem- blages. Table 2 is a comparison ofthe number of species in each family from Lee Creek assemblages and the number of species in the .same families represented in the Holocene Argopecten gibbus community. The number of species be- longing to each of the families is quite similar for each of the two groups (some of the small gastropods, such as the Vitrinellidae and Caecidae, are missing from the lists of Porter and Wolfe (1971:93) because of sampling tech- niques). The similarity of the composition of these two assemblages is very close, considering that almost 65 percent of the species at Lee Creek are extinct. Comparison of the families shows that the general faunal composition has re- mained the same (proportions of predators, scavengers, and different types of filter feeders). Despite the high percentage of extinct species at Lee Creek, many generic and specific faunal similarities can be seen between the Argopecten community and the Lee Creek beds. Porter and Wolfe (1971) note the common presence of (Crepidula aculeata, Crepidula fornicata, Fasciolaria, Oliva, Prunum, Conus, Anadara, Pecten, Eucrassatella, Laevicar- dium, Chione, and Macrocallista in the Argopecten commu- nity. Also, one part of the Argopecten community is sur- rounded by large heads of lobe star coral Solenastrea hyades (Dana). In parts of our beds, Argopecten is common, al- though not abundant. Many of our species are found in close association with Solenastrea at Lee Creek. Considering the number of extinct species and the species replacement in the communities since the late Pliocene, there is a close relationship between the Lee Creek upper Pliocene-lower Pleistocene assemblages and the Holocene Argopecten com- munity. The beds associated with the bar assemblage are thought to be the result of particularly rapid deposition. Circulation and nutrient supply to the area apparently provided ideal conditions for high productivity, resulting in the great di- versity of species and individuals. Similar areas of high productivity have been ob.served by the authors on the present-day continental shelf on shallow bars several miles offshore from Myrtle Beach, South Carolina. CORBICULA-RANGIA PROBLEM.—When the James City as.semblages are examined in detail, several important fea- tures are seen. Two genera, Corbicula and Rangia, are present; these are not normally a.ssociated with Holocene marine deposits. The species at Lee Creek are the bivalves Rangia clathrodonta (Conrad) and Corbicula densata (Con- rad). In other Pliocene and lower Pleistocene deposits in the (Coastal Plain, both of these species are commonly found in shallow marine deposits. They are definitely more abun- dant in shallower water marine fossil deposits than in more offshore deposits. At Lee Creek, specimens of Corbicula range from a few millimeters to more than 50 mm in length. Many specimens are paired and unworn. Specimens that reach adulthood in the freshwater environment often have umbos corroded by fresh water, a feature not observed on Lee Creek specimens. Individuals from low salinity environ- ments may have been transported as larvae and may have established themselves on the offshore bar system and grown to adulthood in the marine environment. Holocene NUMBER 61 125 Winnowing on hiqPis' — — (Regression and erosion followed by a new transgression) 1 Kilometer approximately Mol usca o Cyclocardia <^ Plicatula Q Ostrea ^ Ensis ^ Astarte c^ Marvacrassatella o Mulinia <© Anadara © Anomia ~JK> Crassostrea -j Clayey-fine sand B [::.V-/-j Coarse sand, bedded,burrowed, mottled A I I Clayey-fine sand FIGURE 13.—Depositional phases of the Chowan River and James City Formations at Lee Creek shown by schematic block diagrams. Major macrofaunal elements are shown on each of the block diagrams, and different sediment types for each of the units are indicated. These units correspond with those shown in Figure 3. Bottom: deposition of unit B (Chowan River Formation) over an unconformable surface of the Yorktown Formation. Middle: A brief regression and erosion preceded deposition of the lower bed of the James City Formation (C). A bar complex formed in the area after the deposition of unit C. This bar complex supported a diverse molluscan assemblage. Top: A slight shallowing caused a change in the nature of deposition in the area, and a less diverse assemblage lived in the finer sediments deposited at this time (unit E). representatives of Corbicula and Rangia have not retained the euryhaline range of the Pliocene and early Pleistocene forms, and consequently, only on the very rarest occasion are these ever seen in a shallow marine environment and only then by transport from another environment. Both Rangia and Corbicula, we feel, indicate proximity of land, and their presence in the beds at Lee Creek marks the approximate limit of their range into such marine units. 126 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY TABLE 2.—Comparison of the numbers of species/subspecies p>er family in the Chowan River and James City molluscan assemblages at Lee Creek Mine with those of the Argopecten gibbus community reported by Porter and Wolfe, 1971 (families listed in phylogenetic order; see Checklist, p. 129) Lee Creek Mine Family A. gibbus community Class PELECYPODA Nuculidae 3 1 Nuculanidae 1 0 Arcidae 2 5 Noetiidae 1 1 Glycymerididae 4 2 Mytilidae 6 8 Pectinidae 3 4 Plicatulidae 1 1 Anomiidae 2 3 Ostreidae 2 3 Lucinidae 6 2 Ungulinidae 3 2 Chamidae 1 4 Lasaeidae 2 0 Leptonidae 1 0 Sportellidae 3 0 Carditidae 5 0 Condylocardiidae 1 0 Astartidae 2 0 Crassatellidae 4 1 Cardiidae 2 6 Mactridae 5 2 Cultellidae 1 0 Tellinidae 2 6 Donacidae I 0 Semelidae 3 3 Solecurtidae 1 2 Corbiculidae 1 0 Veneridae 10 7 Perticolidae 2 I Myidae 3 1 Corbulidae 2 3 Gastrochaenidae 1 2 Hiatellidae 1 2 Pholadidae 1 1 Pandoridae 1 1 Periplomatidae 1 0 Thraciidae 1 1 Verticordiidae 2 0 Family Lee Creek A. gibbus Mine community Class SCAPHOPODA Siphonodentaliidae 1 I Class GASTROPODA Fissurellidae 3 1 Trochidae 1 3 Liothiidae 1 0 Littorinidae 1 0 Rissoidae 1 0 Vitrinellidae 6 0 Tornidae 2 0 Caecidae 4 0 Turritellidae 2 1 Vermicularidae 1 I Vermetidae 1 0 Cerithiidae 2 0 Triphoridae 1 0 Epitoniidae 6 2 Melanellidae 5 2 Crepidulidae 5 5 Eratoidae 1 0 Naticidae 3 7 Muricidae 6 6 Columbellidae 7 6 Nas.sariidae 5 2 Melongenidae 4 4 Fa.sciolariidae 3 3 Olividae 2 3 Mitridae 1 0 Volutidae 1 1 Cancellariidae 1 1 Marginellidae 4 5 Conidae 1 2 Terebridae 2 2 Turridae 5 4 Pyraniidellidae 8 2 Ringiculidae 1 0 Acteocinidae 1 2 Crassostrea, generally associated with bays and lagoonal deposits in the Holocene, is abundant in certain units at Lee Creek. Studies of the Holocene range of this species have shown that it can survive in the marine environment (Wells and Gray, 1960), and Stenzel (1971:1039) noted that larvae and young adults tolerate 10-40 parts per thousand and may grow in hyperhaline conditions. Specimens of Crass- ostrea at Lee Creek have a peculiar lamellate growth struc- ture rarely approached by Holocene representatives living in bays and estuaries. Such a growth structure may repre- sent an open-shelf growth habit. The Lee Creek specimens of Crassostrea were adapted to conditions on the inner part of a very broad shelf platform. During late Pliocene and early Pleistocene deposition at Lee Creek, the shelf was at least twice as wide as it is now in the Raleigh Bay area. On such a broad shallow platform, inner-shelf conditions may have been much more influenced by periodic coastal runoff and dilutions. These conditions would explain the associa- tion of Crassostrea with other species at Lee Creek, which are of an open-marine nature (see herein). Many of the NUMBER 61 127 typical very shallow (less than 10 m) marine mollusks (e.g., Donax, Terebra, Ervilia) are either rare or lacking at Lee Creek. THERMAL REGIME.—The thermal regime represented by the upper shell beds at Lee Creek is different from that existing off the coast at the same latitude today. The sublit- toral faunal provinces and equivalent climatic zones in this region off the southeastern United States are: Virginian- mild temperate, Carolinian-subtropical, Caribbean-tropical. At present there is no warm-temperate faunal province in this region and the boundary ofthe Virginian and Carolin- ian provinces is located at Cape Hatteras (latitude 35° 15'N) (Valentine, 1971:17). This sharp boundary exists because of the convergence of isotherms here. The latitude of the Lee Creek locality is approximately 35°20'N, and the as- semblages may have lived south of such a sharp thermal boundary. Almost without exception, living species found in the Lee Creek beds have a subtropical range on the Atlantic continental shelf today. Cape Hatteras today oc- cupies a unique position in that the shelf is extremely narrow at this particular latitude, and hence the barrier has much more influence upon current patterns than any ofthe other capes along the coast. When the Cape Hatteras area was submerged, currents could flow more directly northward, as is shown in Figure 14. The present-day Gulf Stream trends in the same general direction north of Hatteras, but here the trend ofthe continental margin changes to a more westerly direction away from the Gulf Stream axis, as shown by the 200-m depth contour. This change in the continental margin makes Virginia more remote from the Gulf Stream influence. The removal of Cape Hatteras as a barrier to coastal currents would permit the Gulf Stream to influence the marine environments much farther north than at pres- ent (Figure 14), as suggested by the arrows of generalized shelf currents (bottom drift) during Pliocene and early Pleistocene time. Current directions are modified from positions of present shelf currents shown by Bumpus and Lauzier (1965) and Bumpus (1973) and are only meant to suggest (in this paper) generalized directions of bottom drift. A .second factor influencing the composition of the Lee Creek molluscan assemblages is the postulated presence of a warm-temperate province to the north in late Pliocene time, whereas today a mild-temperate climatic zone is found off Virginia. Prior to the deposition of these assemblages at Lee Creek, the Yorktown Sea occupied a large basin in Virginia (Figure 14). Mollusks common to these Yorktown beds, especially to the upper part ofthe Yorktown, include a large number of taxa that are not found in mild-temperate waters but which are warmer water forms including species of Conus (sinistral), Amusium, Glycymeris americana, two spe- cies of Fasciolaria, Sconsia, Chione sp. cf. C. intapupurea, Chama congregata, Cancellaria, Trigonostoma, and Anadara lienosa. Also, a large number of subtropical taxa in the contemporaneous Yorktown Formation to the south are not commonly found in the Virginia Yorktown, including the taxa: Cypraea, Murex, 5 species of Fasciolaria, Trachycar- dium, sinistral Busycon, Turbo, Mitra, Echinochama, Eucras- satella}, and Codakia. For these reasons we believe that the Yorktown Formation, especially the upper part, is repre- sentati\e of a warm-temperate climatic zone. Although this Yorktown basin apparently closed (nondepositional area) when the Yorktown Sea retreated, warm-temperate marine conditions apparently continued to prevail at these latitudes during the deposition of the assemblages at Lee Creek. As many species are not restricted to a single thermal province, a few representatives of such a warm-temperate environ- ment (Astarte berryi and Marvacrassatella kauffmani) are present at Lee Creek. The presence of these warm-temper- ate .species suggests that the Lee Creek deposits may be near to the northernmost part ofthe subtropical thermal regime. Paleotemperatures for these assemblages at Lee Creek are difficult to calculate because of lack of knowledge con- cerning the details of distribution of present-day mollusks on the continental shelf. Temperatures at Lee Creek may have a seasonal range similar to that found on the North Carolina shelf in Onslow Bay at depths of about 20 m. Solenastrea, a coral common at Lee Creek, was reported by Macintyre and Pilkey (1969) in Onslow Bay at this depth in bottom temperatures ranging from 10.6° to about 27° C. More normal temperature ranges for this area may be from 15° to 27° C(Walfordand Wicklund, 1968). Similar paleo- climatic observations for these units were made by Hazel (1971b) on the basis ofthe ostracodes, although he indicated that the winter temperature may have been somewhat warmer than 15° C. Chronology of Late Pliocene and Early Pleistocene Events at the Lee Creek Mine CHOWAN RIVER FORMATION.—A transgressive shallow- water coarse marine sand containing abundant small mol- lusks (unit B) was deposited over finer grained sediments of the Yorktown Formation (unit A) which, here, lack abun- dant well-preserved macrofossils. This coarse marine sand contains a diverse assemblage (in terms of number of spe- cies), which is typical ofthe modern east coast shallow shelf (about 20 m or slightly greater). The most conspicuous members of this assemblage are Cyclocardia and Plicatula (Figure 13). Unit B has been differentially leached and indurated by groundwater flow and the resultant reprecip- itation of carbonate. Apparently leaching took place during a brief period of emergence before deposition of succeeding units. JAMES CITY FORMATION.—In the northern area of the pit, a coarse shelly sand (unit C) was deposited where part of unit B had been eroded. The most conspicuous species here is Mercenaria permagna, which is found in living posi- 128 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Suggested paleocurrents on the late Pliocene and early Pleistocene shelf area ^\ Area In Virginia covered by Yorkf-own Sea which did not receive extensive marine sediments during early Pliocene time. lOOMiles J 1 100 Kilometers — 35' —30' 80' 75' FIGURE 14.—Paleocurrent map for Lee Creek area in late Pliocene and early Plei.stocene time, showing present-day mean axis ofthe Gulf Stream (Arx, Bumpus, and Richard.son, 1955), 200 ni bathymetry, and approximate 100 foot (30.5 ni) elevation contour. NUMBER 61 129 tion. In addition, this assemblage contains many specimens of Ensis, Conradostrea, Cyclocardia and a fairly high number of small molluscan species, the abundance being fairly evenly distributed among taxa. This assemblage is inter- preted as being a shallow-shelf assemblage (about 15 to 20 m in depth). It is succeeded by sediments deposited as part of an offshore bar system (unit D). The main part ofthe bar could not be seen in the present exposures and must be east of our measured sections in the north wall. The north wall deposits at our sections consist of unidirectional steeply dipping current-bedded coarse sands that resulted from bar migration, especially storm- caused bar migration to the southwest. The height of these current-bedded sands is about 6 feet (1.8 m), and the angle of dip is approximately 34°. The current-bedded sands contain abundant large mollusks, large coral pieces {Solen- astrea), regular and irregular echinoid remains, and knobs of cyclostomatous bryozoans. The diversity ofthe mollusks is high in terms of numbers of species. In these current- bedded sands are occasional lenses of almost pure shell hash, whereas elsewhere there are pockets of almost pure sand. The coral pieces found in these beds are very large (more than 0.3 m in height) and have a palmate growth pattern. The construction and influence of another seaward bar- rier, probably in response to a slight lowering of the sea level, resulted in the deposition of unit E, a shallow-shelf clayey sand. Rapid deposition of well-preserved shells took place in topographically lower areas (section 1 of Figure 2) whereas in the higher areas (top of old bar deposits), such as the beds in section 5, winnowing and reworking resulted in the deposition of worn and encrusted shell, much of which is blackened and possibly recycled. At section I, where well-preserved material accumulated, Mercenaria per- magna is abundant, as are Chione grus, Plicatula marginata, and Anomia simplex. At section 5, there is worn and re- worked shell material; Mulinia lateralis and Anadara sequi- costata are the most common species. Systematic Checklist The following hierarchic classification is used in this report: Phylum MOLLUSCA Class PELECYPODA Subclass PALAEOTAXODONTA Order NUCULOIDA Superfamily NUCULACEA Family NUCULIDAE Genus A^Mcw/a Lamarck, 1799 Nucula proxima Say Nucula taphria Dall Nucula pilkeyi, new species Superfamily NUCULANACEA Family NUCULANIDAE Genus Nuculana Link, 1807 Nuculana acuta (Conrad) Subclass PTERIOMORPHA Order ARCOIDA Superfamily ARCACEA Family ARCIDAE Genus Anadara Gray, 1847 Anadara aequicostata (Conrad), new combination Genus Quadrilatera Deshayes, 1860 Quadrilatera adamsi (Dall), new combination Family NOETIIDAE Genus Noetia Gray, 1857 Noetia limula (Conrad) Superfamily LIMOPSACEA Family GLYCYMERIDIDAE Genus Glycymeris da Costa, 1 778 Glycymeris americana (Defrance) Glycymeris arata (Conrad) Glycymeris hummi, new species Glycymeris sloani, new species Glycymeris sp. Order MYTILOIDA Superfamily MYTILACEA Family MYTILIDAE Genus Brachidontes Swainson, 1840 Brachidontes sp. Genus Alytilus Linnaeus, 1758 Mytilus sp. aff. M. edulis Linnaeus C>enus Crenella Brown, 1827 Crenella decussata (Montagu) Genus Musculus Roding, 1798 Musculus lateralis (Say) Genus Moc^io/wi Lamarck, 1799 Modiolus sp. cf. M. modiolus (Linnaeus) Genus Lithophaga Roding, 1798 Lithophaga yorkensis Olsson Order PTERIOIDA Suborder PTERIINA Superfamily PECTINACEA Family PECTINIDAE Genus Leptopecten Verrill, 1897 Leptopecten? auroraensis, new species Genus Carolinapecten, new genus Carolinapecten eboreus (Conrad), new combination Genus Argopecten Monterosato, 1889 Argopecten vicenarius vicenarius (Conrad) Family PLICATULIDAE Genus Plicatula Lamarck, 1801 Plicatula marginata Say Superfamily ANOMIACEA Family ANOMIIDAE Genus/InoOTJd Linnaeus, 1758 Anomia simplex d'Orbigny Genus Pododesmus Philippi, 1837 Pododesmus fragosus (Conrad), new combination Suborder OSTREINA Superfamily OSTREACEA Family OSTREIDAE Genus Crassostrea Sacco, 1897 Crassostrea virginica auroraensis, new subspecies Genus Conradostrea, new genus Conradostrea lawrencei, new species Subclass HETERODONTA Order VENEROIDA Superfamily LUCINACEA Family LUCINIDAE Genus Stewartia Olsson and Harbison, 1953 Stewartia anodonta floridana (Conrad), new combination 130 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Genus Parvilucina Dall, 1901 Parvilucina multilineata (Tuomey and Holmes) Genus Bellucina Dall, 1901 Bellucina waccamawensis (Dall), new combination Genus Cavilinga Chavan, 1937 Cavilinga trisulcata (Conrad), new combination Genus Ca//ucma Dall, 1901 Callucina keenae (Chavan) Genus Divalinga Chavan, 1951 Divalinga sp. Family UNGULINIDAE Genus Diplodonta Bronn, 1831 Diplodonta acclinis (Conrad) Diplodonta berryi McGavock Genus Phlyctiderma Dall, 1899 Phlyctiderma heroni, new species Superfamily CHAMACEA Family CHAMIDAE Genus CAflwja Linnaeus, 1758 Chama gardnerae Olsson and Harbison Family LASAEIDAE Genus Aligena Lea, 1843 Aligena striata Lea Genus Bornia Philippi, 1836 Bornia triangula Dall Family LEPTONIDAE Genus Mysella Angas, 1877 Mysella beaufortensis, new species Superfamily CYAMIACEA Family SPORTELLIDAE Genus Anisodonta Deshayes, 1858 Anisodonta Carolina Dall Genus Sportella Deshayes, 1858 Sportella waccamawensis Gardner Genus Fnsitellops 01s.son and Harbison, 1953 Ensitellops elongata Olsson and Harbison Superfamily CARDITACEA Family CARDITIDAE Genus Carditamera Conrad, 1838 Carditamera arata (Conrad) Genus Pleuromeris Gonvdid, 1867 Pleuromeris auroraensis, new species Pleuromeris decemcostata Conrad Genus Pteromeris Conrad, 1862 Pteromeris perplana (Conrad) Genus Cyclocardia Conrad, 1867 Cyclocardia sp. cf. C. granulata (Say) Family CONDYLOCARDIIDAE Genus Erycinella Conrad, 1845 Erycinella ovalis Conrad Superfamily CRASSATELLACEA Family ASTARTIDAE €>enus Astarte]. Sowerby, 1816 Astarte berryi Gardner Astarte concentrica Conrad Family CRASSATELLIDAE Genus Marvacrassatella, new genus Marvacrassatella kauffmani, new species Genus Crassinella Guppy, 1 874 Cras.sinella dupliniana (Dall) Crassinella lunulata (Conrad) (Jrassinella johnsoni, new species Superfamily CARDIACEA Family CARDIIDAK Cjenus Laevicardium .Swainson, 1840 Laevicardium sublineatum (Conrad) Genus Dinocardium Dall, 1900 Dinocardium robustum hazeli, new subspecies Superfamily MACTRACEA Family MACTRIDAE Genus Mulinia Gray, 1837 Mulinia lateralis (Say) Genus Rangia Desmoulins, 1832 Rangia clathrodonta (Conrad) G>enus Spisula Gray, 1837 Spisula similis (Say) Spisula solidissima (Dillwyn) Genus Raeta Gray, 1853 Raeta plicatella (Lamarck) Superfamily SOLENACEA Family CULTELLIDAE Genus Ensis Schumacher, 1817 Ensis directus (Conrad) Superfamily TELLINACEA Family TELLINIDAE Genus Tellina Linnaeus, 1758 Tellina agilis Stimpson Genus Macoma Leach, 1819 Macoma holmesii Dall Family DONACIDAE Genus Donax Linnaeus, 1758 Donax fossor Say Family SEMELIDAE Genus S^mW^" Schumacher, 1817 Semele bellastriata (Conrad) Genus/liira Lamarck, 1818 Abra aequalis (Say) Genus Cumingia Sowerby, 1833 Cumingia tellinoides (Conrad) Family SOLECURTIDAE Genus Tagelus Gray, 1847 Tagelus plebeius carolinensis (Conrad) Superfamily CORBICULACEA Family CORBICULIDAE Genus Corbicula Mergele von Miihlfeld, 1811 Corbicula densata (Conrad) Superfamily VENERACEA Family VENERIDAE Genus Gouldia C. B. Adams, 1847 Gouldia metastriatum (Conrad) Genus Transennella Dall, 1883 Transennella stimpsoni Dall Genus Pi/ar Romer, 1857 Pilar chioneformis (Gardner), new combination Cjenus Macrocallista Meek, 1876 Macrocallista greeni, new species Genus/^ojfnia Scopoli, 1777 Dosinia sp. Cjenus Gemma Deshayes, 1853 Gemma magna majorina Gardner Cjenus Chione Megerle von Miihlfeld, 1811 Chione grus (Holmes) Chione cribraria (Conrad) Genus Mercenaria Schumacher, 1817 Mercenaria permagna (Conrad), new combination Mercenaria mercenaria (Linnaeus) Family PETRICOLIDAE Genus Petricola Lamarck, 1801 Petricola pectorosa (Conrad) Petricola pholadiformis Lamarck Order MYOIDA Suborder MYINA NUMBER 61 131 Superfamily MYACEA Family MYIDAE Genus Mya Linnaeus, 1758 Mya arenaria Linnaeus Genus Param^Jfl Conrad, 1861 Paramya subovata (Conrad) Genus 5/)/j?nJa Turton, 1822 Sphenia dubia (Lea) Family CORBULIDAE Genus Caryocorbula Gardner, 1926 Caryocorbula auroraensis, new name Caryocorbula contractu (Say), new combination Superfamily GASTROCHAENACEA Family GASTROCHAENIDAE Genus Gai/roc/ia^na Spengler, 1783 Gastrochaena hians (Gmelin) Superfamily HIATELLACEA Family HIATELLIDAE Genus Pcno/)ra Menard, 1807 Panopea floridana Heilprin Suborder PHOLADINA Superfamily PHOLADACEA Family PHOLADIDAE Genus Cyrtopleura Tryon, 1862 Cyrtopleura sp. Subclass ANOMALODESMATA Order PHOLADOMYOIDA Superfamily PANDORACEA Family PANDORIDAE Genus Pandora Bruguiere, 1797 Pandora tuomeyi Gardner and Aldrich Family PERIPLOMATIDAE Genus Coc/i/orfwma Couthouy, 1839 Cochlodesma emmonsii, new species Family THRACIIDAE Genus Thracia Sowerby, 1823 Thracia brioni, new species Order SEPTIBRANCHOIDEA Superfamily POROMYACEA Family VERTICORDIIDAE Genus Verticordia Sowerby, 1844 Verticordia emmonsii Conrad Verticordia lockei, new species Class SCAPHOPODA Family SIPHONODENTALIIDAE Genus C^adulus Philippi, 1844 Cadulus quadridentatus (Dall) Class GASTROPODA Subclass PROSOBRANCHIA Order ARCHAEOGASTROPODA Superfamily FISSURELLACEA Family FISSURELLIDAE Genus Z)zorfora Gray, 1821 Diodora nucula (Dall) Diodora auroraensis, new species Diodora pamlicoensis, new species Superfamily TROCHACEA Family TROCHIDAE Genus Ca//toitoTOC Swainson, 1840 Calliostoma philanlhropum pontoni Mansfield Family LIOTIIDAE Genus Arene H. and A. Adams, 1854 Arene pergemma (Gardner), new combination Superfamily LITTORINACEA Family LITTORINIDAE Genus Littorina Ferussac, 1822 Litlorina carolinensis Conrad Superfamily R1S.SOACEA Family RIS.SOIDAE Genus Rissoa Freminville, 1814 Rissoa geraea Dall Family VITRINELLIDAE Genus Teinostoma A. Adams, 1851 Teinostoma goniogyrus Pilsbry and McGinty Teinostoma smirkon Gardner Teinostoma beaufortensis, new species Teinostoma tectispira Pilsbry Genus Cyclostremiscus Pilsbry and Olsson, 1945 Cyclostremiscus obliquestriatus (Lea) Genus Dirfian^Tna Woodring, 1928 Didianema carolinae Gardner Superfamily ToRNACEA Family TORNIDAE Genus Macromphalina Cossmann, 1888 Macromphalina pierrot Gardner Macromphalina hanseni, new species Family CAECIDAE Genus Caecum Fleming, 1813 Caecum beaufortensis, new species Caecum pulchellum Stimpson Caecum imbricatum Carpenter Caecum flemingi Gardner and Aldrich Superfamily CERITHIACEA Family TURRITELLIDAE Genus Turritella Lamarck, 1799 Turritella beaufortensis, new species Turritella perexilis Conrad Family VERMICULARIDAE Genus Vermicularia Lamarck, 1799 Vermicularia spirata (Philippi) Family VERMETIDAE Genus Serpulorbis Sdss\, 1827 Serpulorbis granifera (Say), new combination Family CERITHIIDAE Genus Bi//ium Gray, 1847 Bittium podagrinum Dall Genus Seila A. Adams, 1861 Seila adamsii (Lea) Family TRIPHORIDAE Genus Triphora Blainville, 1828 Triphora dupliniana (Olsson) Order PTENOGLOSSA Superfamily EPITONIACEA Family EPITONIIDAE Genus Epitonium Roding, 1798 Epitonium leai, new species Epitonium sohli, new species Epitonium sp. cf. E. foliaceicostum (d'Orbigny) Epitonium carolinae Gardner Epitonium rupicolum (Kurtz) Epitonium fractum Dall Suborder GYMNOGLOSSA Family MELANELLIDAE Genus £c/d5 Gray, 1847 Balcis? sp. Balcis beaufortensis, new species Balcis biconica (Gardner), new combination Balcis eborea (Conrad), new combination Genus Eulima Risso, 1826 Eulima juncea (Gardner), new combination Superfamily CREPIDULACEA Family CREPIDULIDAE 132 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Genus Crucibulum Schumacher, 1817 Crucibulum lawrencei, new species Cjenus Calyptraea Lamarck, 1799 Calyptraea centralis (Conrad) Genus Crepidula Lamarck, 1799 Crepidula aculeata (Gmelin) Crepidula fornicata (Linnaeus) Crepidula plana Say Superfamily CYPRAEACEA Family ERATOIDAE Genus Trivia Broderip, 1837 Trivia floridana Olsson and Harbison Superfamily NATICACEA Family NATICIDAE Genus Polinices Montfort, 1810 Polinices duplicata (Say) Genus Lunatia Gray, 1847 Lunatia heros (Say) Genus Tectonatica Sacco, 1890 Tectonatica pusilla (Say) Superfamily MURICACEA Family MURICIDAE Genus Murexiella Clench and Perez Farfante, 1945 Murexiella macgintyi (M. Smith), new combination Genus Urosalpinx Stimpson, 1865 Urosalpinx sp. cf. U. perrugata (Conrad) Urosalpinx stimpsoni Gardner Urosalpinx suffolkensis Gardner Genus Pterorhytis Gonrzd, 1862 Pterorhytis conradi (Dall), new combination Genus Eupleura H. and A. Adams, 1853 Eupleura caudata (Say) Superfamily BUCCINACEA Family COLUMBELLIDAE GENVS Mitrella Risso, 1826 Mitrella gardnerae ecarinata (Olsson and Harbison), new combi- nation Mitrella gardnerae gardnerae (Olsson and Harbison), new com- bination Mitrella waccamawensis Gardner Genus Anachis H. and A. Adams, 1853 Anachis milleri Gardner Genus/t«o/»w5 Gould, 1860 Aesopus gardnerae, new species Aesopus ithitoma (Dall) Aesopus stearnsii (Tryon) Family NAS.SARIIDAE Genus A^a55anM5 Dumeril, 1806 Nassarius chowanensis (Gardner), new combination Nassarius cornelliana (Olsson) Nassarius granifera (Conrad), new combination Nassarius schizopyga? (Dall), new combination Nassarius scalaspira? (Conrad), new combination Family MELONGENIDAE Genus Busycon Roding, 1798 Bu.'iycon spiratus pyruloides (Say) Busycon adversarius Conrad Busycon carica (Gmelin) Busycon concinnum Conrad P'amily FASCIOLARIIDAE Genus Fasciolaria Lamarck, 1799 Fasciolaria cronlyensis Gardner Fasciolaria beaufortensis, new .species Cjenus LIeilprinia Gnhzu, 1904 Heilprinia caloosaensis malcolmi, new subspecies Superfamily VOLUTAGEA Family OLIVIDAE Genus 0/iva Bruguiere, 1789 Oliva carolinensis (Conrad) Genus 0/iw//a Swainson, 1831 Olivella mutica (Say) Family MITRIDAE Genus Vm//Mm Roding, 1798 Vexillum wandoense (Holmes) Family VOLUTIDAE Genus VO/M«J/M5U5 Conrad, 1863 Voiutifusus typus Conrad Family CANCELLARIIDAE Genus Trigonostoma Blainville, 1827 Trigonostoma sp. Family MARGINELLIDAE Genus Granw/i'na Jousseaume, 1888 Granulina ovuliformis (d'Orbigny) Genus Prunum Hermannsen, 1852 Prunum limatulum (Conrad), new combination Genus D^niimar^o Cossmann, 1899 Dentimargo polyspira? (Olsson and Harbison), new combination Genus Volvarina Hinds, 1844 Volvarina avena (Kiener), new combination Family CONIDAE Genus Conus Linnaeus, 1758 Conus adversarius Conrad Family TEREBRIDAE Genus Strioterebrum Sacco, 1891 Strioterebrum sp. cf. 5. petiti Olsson Strioterebrum .sp. Family TuRRiDAE Genus Cymatosyrinx DnW, 1889 Cymatosyrinx lunata (Lea) Genus Sedilia Fargo, 1953 Sedilia sp. aff 5. sedilia (Dall) Cjenus Vitricythara Fargo, 1953 Vitricythara micromeris (Dall) Genus G/a6roQiarolina and Virginia. Specimens from Lee Creek are ques- tionably referred to this species. FIGURED SPECIMEN.— USNM 204088 from USGS 25339. OCCURRENCE.—Collected as spoil material. TYPE LOCALITY.—Virginia. Genus ^u^ycon Roding, 1798 Busycon spiratus pyruloides (Say) PLATE 41: FIGURES 5, 6; PLATE 42: FIGURE 3 Fulgur pyruloides Say, 1822:237. Busycotypus (Pyrofulgur) spiratus pyruloides (Say).—Hollister, 1958:100- NUMBER 61 177 102, pl. 15: figs. 10, 11: pl. 16: figs. 10, 14: pl. 17: fig. 8 [neotype designated]. Busycon spiratum pyruloides (Say).—Abbott, 1974:223, fig. 2451, pl. 6. DISCUSSION.—Our figured specimen (Plate 41: figure 6). shows a pattern of small holes bored by Bryozoa. Such borings are common in many shells at Lee Creek. Plate 42: figure 3 shows a specimen in which the canal is less elevated, and we tentatively refer this specimen to this species. This species was not recorded by Gardner (1948) or by Olsson and Harbison (1953). Hollister (1958:100) stated that this species is Busycon pyrum of authors (not of Dillwyn, 1817). FIGURED SPECIMENS.—USNM 204089 from USGS 25371 (Plate 41: figures 5, 6) and USNM 204092 from USGS 25364 (Plate 42: figure 3). OCCURRENCE.—This species is recorded from sections 2 (D), 4 (D), and 6 (C). TYPE LOCALITY.—Neotype of Hollister was collected on Siesta Key, Sarasota, Manatee County, Florida (Holocene). Busycon adversarius Conrad PLATE 41: FIGURE 7 Busycon adversarium Conrad, 1863a:560. DISCUSSION.—Conrad introduced the name "Busycon ad- versarium C." in a list and indicated that this name takes the place of "5. perversum Tuomey and Holmes, (not Lam.,) Plioc. Foss, S. C. 145, 29, 3." Actually B. perversum is a species described by Linnaeus and not Lamarck, contrary to Conrad's reference. Also Gardner (1948:239 in text) gave an incorrect reference to B. adversarius when she stated that the species referred to was in Tuomey and Holmes, 1856, plate 29: figure 2, whereas the correct reference is plate 29: figure 3. This species was not recorded by Olsson and Harbison (1953). Gardner (1948:239, pl. 35: figs. 1, 3) described a subspecies Busycon perversum robesonense, which is very dif- ferent from "B. perversum' in that it has stronger spiral sculpture, the axials are more numerous and nodose rather than spiney. FIGURED SPECIMEN.—USNM 204090 from USGS 25364. OCCURRENCE.—This species is recorded from sections 2 (D), 3 (D, E), 4 (D), and 5 (B, C, D). TYPE LOCALITY.—Pee Dee River, South Carolina. Busycon carica (Gmelin) PLATE 42: FIGURES 1, 2 Murex carica Gmelin, 1791:3545, no. 67. Busycon (Busycon) aruanum.—Hollister, 1958:70-78, pl. 8: figs. 1-3, 5-11; pl. 18: figs. 3, 5. Busycon carica (Gmelin).—Abbott, 1974:222, fig. 2440. Not Murex aruanus Linnaeus, 1758:753, no. 484. DISCUSSION.—There is some controversy as to whether this species is Murex aruanus of Linnaeus or is Murex carica Gmelin. Linnaeus apparently had two species belonging to different genera when he was describing aruanus. The locality cited by Linnaeus (New Guinea) and the first figure cited are a species later called Fusus probosidiferus by La- marck (Dodge, 1957:160-162). Gmelin (1791:3545), the first reviser of this composite species of Linnaeus, listed aruanus and carica separately as valid species, and in general the diagnoses are mutally exclusive (Dodge, 1957:160- 162). This species is not recorded by Olsson and Harbison (1953) or by Gardner (1948). FIGURED SPECIMEN.—USNM 204091 from USGS 25364. OCCURRENCE.—This species is recorded from sections 3 (D, E) and 4 (D). TYPE LOCALITY.—None given. Busycon concinnum Conrad PLATE 42: FIGURES 4, 5 Busycon (Sycotypus) concinnum Conrad, 1873:23.—Gardner, 1948:242-243, pl. 33: figs. 1, 3. DISCUSSION.—This species was not recorded by Olsson and Harbison (1953). Gardner (1948) listed it from several Waccamaw Formation localities in North Carolina. The specimens from Lee Creek are very close morphologically to specimens in the Waccamaw Formation of southern North Carolina. FIGURED SPECIMEN.—USNM 204093 from USGS 25370. OCCURRENCE.—This species is recorded from sections 4 (D) and 6 (C). TYPE LOCALITY.—Mr. King's marl pit, Sampson County, North Carolina. Genus Fasciolaria Lamarck, 1799 Fasciolaria cronlyensis Gardner PLATE 43: FIGURES 1,2 Fasciolaria cronylensis Gardner, 1948:254, pl. 36: figs. 1, 2, 3, 6. DISCUSSION.—The figured specimen is the only specimen found at Lee Creek and is the only reported occurrence outside ofthe type locality. FIGURED SPECIMEN.—USNM 204094 from USGS 25364. OCCURRENCE.—This species is recorded from section 4 (D). TYPE LOCALITY.—Neills Eddy Landing, Columbus County, North Carolina (Waccamaw Formation). 178 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Fasciolaria beaufortensis, new species PLATE 43: FIGURES 3-5 DIAGNOSIS.—Shell medium sized, fusiform, whorls con- vex, smooth except for faint, irregular growth lines, exte- rior spiral color bands in some specimens show about 4 thin bands on each whorl, nucleus slightly swollen, smaller than the succeeding whorls, smooth, subglobular, followed by a nearly smooth half-whorl, next half whorl with closely spaced annular folds with the interspaces and folds of about equal size, next whorl continues to have annular folds and these are crossed by 3 spiral bands, slightly incised, flat bottomed, and with the spacing between the anteriormost band and the middle band greater than that between the middle and posterior one; remaining whorls smooth with only a few faint spiral lines on the base, aperture subellipt- ical, prolonged forward into a moderately long anterior canal, not recurved at the end, with a small posterior canal in the upper lip junction, outer lip not thickened, lirate within, parietal wall with a thin glaze of callus, the columella somewhat thickened below and with two long oblique plaits. A spiral ridge emerges from the aperture below the suture and extends across the parietal wall to the margin of the callus. DISCUSSION.—This species differs from the Holocene Fasciolaria hunteri G. Perry, 1811, and F. tulipa Linnaeus, 1758, in being less slender and in having ornamented early whorls. FIGURED SPECIMENS.—USNM 204095 from USGS 25364 (Plate 43: figure 3) and USNM 204096 from USGS 25362, holotype, 82.0 mm (Plate 43: figures 4, 5). OCCURRENCE.—This species is recorded from sections 3 (D, E) and 4 (D, E). TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25362, section 3, unit D. Genus Heilprinia Grabau, 1904 Heilprinia caloosaensis malcolmi, new subspecies PLATE 43: FIGURES 6-8 DIAGNOSIS.—Shell fusiform, with a rounded body-whorl. Sculpture of axial ribs and slightly elevated spiral cords, the ribs tending to become reduced on later whorls. Sutures distinct, the adjacent area on the posterior part of each whorl wide, sloping, and appressed. Two nuclear whorls present with closely spaced axial ribs followed by about 6 postnuclear whorls which have about 4 to 5 spiral cords on the spire whorls (about 10 to 11 on the body whorl, cords also extending the length of the siphon) along with the rounded axial ribs. Whole surface of shell roughened by axial growth lines. Aperture ovate, siphonal canal nearly straight, very small posterior sinus present. Anterior end of aperture extremely narrowed and prolonged along the an- terior canal. Inner lip with a shelf of callus, free-edged externally. Both inner and outer lip on the inner side. DISCUSSION.—This subspecies differs from Heilprinia ca- loosaensis (Heilprin, 1887:68, pl. 1: fig. I) in having much more rounded body whorls, less prominent spiral cords, and less prominent axial ribs. Heilprinia caloosaensis florida (Olsson and Harbison, 1953:219) differs in having a much more shouldered appearance with stronger axial ribs and a longer siphonal canal in proportion to the rest of the shell. Our subspecies differs from Heilprinia caloosaensis carolinen- sis (Dall, 1892:234) in having a smoother and more ex- tended posterior area on each whorl. FIGURED SPECIMENS.—USNM 204097 from USGS 25648, holotyjDe, height 76.5 mm (Plate 43: figures 6, 8), USNM 204098 from USGS 25371 (Plate 43: figure 7). OCCURRENCE.—This species is recorded as float. TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25638. Genus Oliva Bruguiere, 1789 Oliva carolinensis (Conrad) PLATE 44: FIGURES 5, 6 Dactylus Carolinensis Gonrad, 1863a:563; 1863b:584. Oliva carolinensis (Conrad).—Olsson and Harbison, 1953:184. DISCUSSION.—Oliva sayana is a morphologically variable species that is strongly influenced by the environment. Examination of some Holocene collections suggests that more highly spired forms may be associated with certain nearshore conditions and more lowly spired ones with deeper water. We believe the specimens at Lee Creek to represent the low-spired form of this species. The more highly .spired form is figured by Olsson and Harbison (1953:184, pl. 29: figures 4, 4a). Richards (1968:112) sug- gested that the specimen figured by Olsson and Harbison (their \'>\. 29: fig 4) may be one of Conrad's type specimens (ANSP 14654). Conrad did not figure his specimen. This species was not recorded by Gardner (1948). FIGURED SPECIMEN.—USNM 204099 from USGS 25371. OCCURRENCE.—This species is recorded from section 5 (B). l^PE LOCALITY.—"Dauphin County, North Carolina, Professor Mitchell" (Conrad, 1863a) (actually Duplin (>ounty; probably Yorktown Formation). Genus Olivella Swainson, 1831 Olivella mutica (Say) PLATE 44: FIGURE 7 Oliva mutica Say, 1 822:228. Olivella (Dactylidia) mutica (Say).—Olsson and Harbison, 1953:186, pl. 39: fig. 7. NUMBER 61 179 DISCUSSION.—Specimens at Lee Creek are referred to this species. There is great morphologic variation in this group, and resolution of this variation needs to be done on the Holocene species. Olsson and Harbison (1953, pl. 39: fig. 7) recorded this species from St. Petersburg and from Fort Thonijjson, Florida. Their figured specimen is some- what stouter than our specimens. Such differences may be only local differences. Say's type specimen is apparently lost. Gardner (1948) did not rcord this species. FIGURED SPECIMEN.—USNM 204100 from USGS 25366. OCCURRENCE.—This species is found at sections 2 (B, D), 3 (D, E), 4 (B, D), and 5 (B, C, D, E). TYPE LOCALITY.—"Inhabits the southern shores. . . ," East Florida. glazed on the exterior ofthe shell, so much so as to obscure the early whorls. ALso the columella is .strongly curved, but the specimen is similar to the Lee Creek species in not being shouldered. This species was not recorded by Gardner (1948) or by Olsson and Harbison (195.3). The type species of Voiutifusus is V. mutabilis (Conrad, 1834) from the St. Marys Formation, St. Marys River, Maryland. FIGURED SPECIMENS.—USNM 204102 from USGS 25364 (Plate 44: figure 1) and USNM 204103 from USGS 25364 (Plate 44: figures 2, 3). OCCURRENCE.—This species is found at sections 3 (D, E), 4 (D), and 6 (C). TYPE LOCALITY.—North Carolina. Genus Vexillum Roding, 1798 Vexillum wandoense (Holmes) PLATE 45: FIGURE 8 Volutomitra wandoensis Holmes, 1859:77, pl. 12: figs. 10, 10a. Vexillum (Costellaria) wandoense (Holmes).—Abbott, 1974:240. DISCUSSION.—This species was not recorded by Gardner (1948) or by Olsson and Harbison (1953). The larger num- ber of axial ribs and spiral cords distinguish this species from Vexillum holmesii (Dall, 1890). FIGURED SPECIMEN.—USNM 204101 from USGS 25366. OCCURRENCE.—This species is recorded from section 5 (B, C). TYPE LOCALITY.—"Post-Pliocene marl of Wando River,' South Carolina (Holmes, 1859:77). Genus Voiutifusus Conrad, 1863 Voiutifusus typus Conrad PLATE 44: FIGURES 1-3 Voiutifusus typus Conrad, 1866:67, pl. 3: fig. 2. DISCUSSION.—Conrad (1866) stated that this species has a columella with 2 distinct little prominent folds. The spec- imens at Lee Creek agree quite well with Conrad's figure and on the surface of all specimens, especially younger specimens, fine spiral threads may be seen (Plate 44: figure 1). Martin (1904:175) incorrectly referred the specimens in zone 17 ofthe Choptank Formation to this species. In the Eastover Formation, the specimens of this genus are more shouldered in the early whorls and have a more enameled exterior with no spiral lines showing. Also the columella is not as straight in these Miocene specimens. In the upper part of the Yorktown Formation (fragmentary shell beds) at 0.5 mile (0.8 km) above Morgarts Beach, Isle of Wight County, Virginia, a specimen was found which is heavily Genus Trigonostoma Blainville, 1827 Trigonostoma sp. PLATE 45: FIGURE 7 DISCUSSION.—Only one fragment of a specimen belong- ing to this genus was found. FIGURED SPECIMEN.—USNM 204109 from USGS 25362. OCCURRENCE.—This species is recorded form section 3 (D). Genus Granulina Jousseaume, 1888 Granulina ovuliformis (d'Orbigny) PLATE 44: FIGURE 4; PLATE 45: FIGURE 1 Marginella ovuliformis d'Orbigny, 1842(2): 101., pl 20: figs. 33-35. Granulina ovuliformis (d'Orbigny).—Abbott, 1974:254, fig. 2774. Marginella (Gibberula) lachrimula Gould, 1862:238. Cypraeolina lachrimula (Gould).—Gardner, 1948:263-264, pl. 38: figs 20, 21.—Olsson and Harbison, 1953:200. DISCUSSION.—Olsson and Harbison (1953) recorded this species as abundant from St. Petersburg, Florida. Gardner (1948) recorded it from Suffolk, Virginia, from Hamilton Bluff on the Roanoke River, North Carolina, and from Wilson, Colerain Landing, and Natural Well, all in North Carolina. FIGURED SPECIMENS.—USNM 204107 from USGS 25368 (Plate 44: figure 4) and USNM 204129 from USGS 25368 (Plate 45: figure 1). The specimen in figure 4 lacks part ofthe thin outer shell layer. OCCURRENCE.—This species is common in section 5, units B and C, abundant in unit D, and rare in unit E. This S]3ecies is also recorded from sections 3 (D, E) and 4 (D). ORIGINAL LOCALITIES.—Martinique, Saint-Thomas, Guadeloupe (Holocene). 180 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY Genus Prunum Herrmannsen, 1852 Prunum limatulum (Conrad), new combination PLATE 44: FIGURES 11-14 Marginella limatula Conrad, 1834:140. DISCUSSION.—Plate 44: figure 11 shows some of the original color pattern ofthe shell, especially where some of the outer layer is missing. This species differs from Prunum pardalis (Dall, 1890) in being stouter and in having a lower spire. Prunum eulima (Dall, 1892) differs in being more slender than Prunum limatulum. This species was not re- corded by Gardner (1948) or by Olsson and Harbison (1953). FIGURED SPECIMENS.—USNM 204105 from USGS 25366 (Plate 44: figure 1 l)and USNM 204106 from USGS 25366 (Plate 44: figures 12-14). OCCURRENCE.—This species is abundant in section 5, units B, C, and D, and is common in unit E. It is also recorded from sections 1 (E), 3 (D, E), 4 (B, D, E), and 6 (C). TYPE LOCALITY.—Suffolk, Virginia. Genus Dentimargo Cossmann, 1899 Dentimargo polyspira? (Olsson and Harbison), new combination PLATE 44: FIGURES 8, 9 Marginella (Eburnospira) polyspira Olsson and Harbison, 1953:202, pl. 31: figs. 3, 3a, 3b. DISCUSSION.—Specimens from Lee Creek are tentatively referred to this species. They differ from that figured by Olsson and Harbison (1953) in being smaller and in having a less widely flaring lip with a narrower outline. Dentimargo aureocincta (Stearns, 1872) is less elongate and the sutures are more impressed. FIGURED SPECIMEN.—USNM 204104 from USGS 25367. OCCURRENCE.—This sf^ecies is common in section 5, units B, C, and D, and rare in unit E. It is also recorded from sections 2 (D), 3 (D, E), and 4 (B, D). TYPE LOCALITY.—St. Petersburg, Florida (Caloosa- hatchee Formation). Genus Volvarina Hinds, 1844 Volvarina Hinds fide Keen, 1971:635. Volvarina avena (Kiener), new combination PLATE 44: FIGURE 10 Marginella avena Kiener, 1834:17-18. DISCUSSION.—The figured specimen is the only one found in the Lee Creek samples. This species was not recorded by Olsson and Harbison (1953) or by Gardner (1948). Our specimen is similar to that figured by Warmke and Abbott (1961:129, pl. 23H). Our specimen is a little less slender than that shown in their figure. FIGURED SPECIMEN.—USNM 204108 from USGS 25366. OCCURRENCE.—This species is rare at section 5, unit B. TYPE LOCALITY.—"Habite les mers des Indes Occiden- tales' (Kiener, 1834:18) (West Indies). Genus Conus Linnaeus, 1758 Conus adversarius Conrad PLATE 45: FIGURES 2, 3 Conus adversarius Conrad, 1840b:388. DISCUSSION.—This species was not recorded by Gardner (1948). Olsson and Harbison (1953:171, pl. 27: figs. 1, la) recorded Conus adversarius tryoni (Heilprin, 1886) from St. Petersburg, LaBelle, and Ortona Locks, Florida. The nom- inate subspecies is larger with strongly descending sutures. FIGURED SPECIMEN.—USNM 204110 from USGS 25364. OCCURRENCE.—This species is recorded from sections 3 (D, E) and 4 (D). TYPE LOCALITY.—Duplin County, North Carolina (Yorktown Formation). Genus Strioterebrum Sacco, 1891 Strioterebrum sp. cf. S. petiti Olsson PLATE 45: FIGURE 12 DISCUSSION.—Although only a fragment, this specimen resembles Strioterebrum petiti Olsson, 1967. His specimen is from the Waccamaw Formation, Crescent Beach Airport, South Carolina. FIGURED SPECIMEN.—USNM 204119 from USGS 25369. OCCURRENCE.—This species is recorded from section 5 (E). Strioterebrum sp. PLATE 45: FIGURE 11 DISCUSSION.—Although somewhat similar to the speci- men from Lee Creek figured as Strioterebrum sp. cf. 5. petiti Olsson (Plate 45: figure 12), this specimen differs in that it has fewer s]3iral cords that are bounded by more deeply impres.sed lines. Also, axial cords on this specimen are fewer. This is [probably an undescribed species. NUMBER 61 181 FIGURED SPECIMEN.—USNM 204118 from USGS 25366. OCCURRENCE.—This species is recorded from section 5 (B). Genus Cymatosyrinx Dall, 1889 Cymatosyrinx lunata (Lea) PLATE 45: FIGURES 4-6 Pleurotoma lunatum Lea, 1843a: 11; 1846:269-270, pl. 37: 93. DISCUSSION.—Collections of this species from a single horizon from various localities in the Coastal Plain show this to be a highly variable species. Variation in the expres- sion of exterior sculpture (number of axial ribs and their strength) and variation in the ratio of height to length is common. This species was not recorded by Gardner (1948). Fargo (1953:369) recorded this species from St. Petersburg, Florida. FIGURED SPECIMENS.—USNM 204111 from USGS 25367 (Plate 45: figures 4, 6) and USNM 204112 from USGS 25368 (Plate 45: figure 5). OCCURRENCE.—This species is recorded from section 5 (B, C, D). TYPE LOCALITY.—Petersburg, Virginia (Yorktown For- mation.) Genus Sedilia Fargo, 1953 Sedilia sp, aff. S. sedilia (Dall) PLATE 45: FIGURES 9, 10 Sediliasp., near Drillia sedilia Dall.—Fargo, 1953:370, pl. 17: fig. 1. DISCUSSION.—The type locality of Sedilia sedilia (Dall) is "Caloosahatchie beds, rare." Specimens from Lee Creek correspond quite well to that figured by Fargo (1953, pl. 17) as Sedilia sp., near Drillia sedilia Dall. These specimens differ from Sedilia sedilia (Dall, 1890, pl. 2: fig. 1) in having much fewer axial ribs and weaker spiral cords. FIGURED SPECIMEN.—USNM 204113 from USGS 25368. OCCURRENCE.—This species is recorded from 5 (D). Genus Vitricythara Fargo, 1953 Vitricythara micromeris (Dall) PLATE 46: FIGURE 4 Cythara micromeris Dall, 1903, pl. 60: fig. 16 [no text]. DISCUSSION.—Our sole specimen of this species from Lee Creek is small. We refer this specimen to V. micromeris (Dall) although there are some differences in sculpture and our specimen is not as shouldered. This species was not recorded by Gardner (1948). Fargo (1953:396, pl. 21: fig. 2) re- corded this species from St. Petersburg, Florida. FIGURED SPECIMEN.—USNM 204117 from USGS 25368 (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (D). TYPE LOCALITY.—Pliocene marl of Shell Creek, Florida. Genus Glabrocythara Fargo, 1953 Glabrocythara sp, PLATE 46: FIGURES 3, 5 DISCUSSION.—Two worn specimens from Lee Creek are referred to this rare genus. FIGURED SPECIMENS.—USNM 204115 from USGS 25368 (Plate 46: figure 3, SEM photograph) and USNM 204116 from USGS 25367 (questionably referred to this species) (Plate 46: figure 4). OCCURRENCE.—This species is recorded from section 5 (C, D). Genus Brachycythara Woodring, 1928 Brachycythara reidenbachi, new species PLATE 46: FIGURES 1, 2 DIAGNOSIS.—Shell small, slender, apex blunt, whorls an- gular at the periphery, constricted to the impressed sutures. Shoulders steeply sloping, about half the height of the whorls, the protoconch of 2 to 2'/2 volutions, blunt at apex, its tip minute, immersed, rapidly enlarging, the first volu- tion smooth, the following with fairly strong and subequal spiral and axial threads. The conch is dominated by low, narrow, rounded, fairly widely spaced axial ribs, higher at the periphery, narrowing posteriorly, and more widely spaced on later whorls. The entire surface of the conch is covered with very fine and very closely spaced spiral cords, which are crossed by very fine, closely spaced axial cords of about the same size so that a fine-textured appearance is given to the entire surface. Aperture long and fairly narrow, almost half the total length ofthe shell, its width about one- third of its length, canal hardly differentiated, base slightly broken. DISCUSSION.—This species differs from Brachycythara galae dimonia (Fargo, 1953) in having a much finer beaded surface sculpture, in having a shorter posterior slope on the whorls, and in having a slightly shorter aperture. Olsson's figure (1916:5, pl. 2: fig. 12) of Mangilia smithfieldensis Olsson, 1916, appears similar to this species, but his descrip- tion is not complete enough to be definitive, his figured 182 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY specimen does not show any of the fine sculpture (largely because of the quality of the figure), and his specimen is almost twice as large as our specimens. This species is named in honor of F.W. Reidenbach, a paleontologist who has given much encouragement and guidance to the junior author. FIGURED SPECIMEN.—USNM 204114 from USGS 25369, holotype, height 3.6 mm (SEM photograph). OCCURRENCE.—This species is recorded from sections 4 (D) and 5 (D, E). TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25369, section 5, unit E. Genus Odostomia Fleming, 1813 Odostomia simplex (Lea), new combination PLATE 46: FIGURE 6 Acteon simplex Lea. 1843a:8; 1846:258. pl. 36: fig. 62. DISCUSSION.—This species was not recorded by Gardner (1948) or by Olsson and Harbison (1953). Odostomia laevi- gata d'Orbigny, 1842, as illustrated by Warmke and Abbott (1961:147, pl. 26k), has more rounded whorls and more whorls in proportion to its size. Odostomia canaliculata C.B. Adams, 1850, as illustrated by Warmke and Abbott (1961:148, pl. 261) has a more square aperture. We have compared our specimen with that ofthe type. FIGURED SPECIMEN.—USNM 204118 from USGS 25369 (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (CD). TYPE LOCALITY.—Petersburg, Virginia (Yorktown For- mation). Odostomia turbinatus (Lea), new combination PLATE 46: FIGURE 7 Acteon turbinatus Lea, 1843a:7; 1846:256, pl. 36: fig. 56. DISCUSSION.—This species was not recorded by Gardner (1948) or by Olsson and Harbison (1953). Odostomia turbi- natus has much more rapidly expanding whorls than any species illustrated by Warmke and Abbott (1961). We have compared our specimen with the type specimen. FIGURED SPECIMEN.—USNM 204119 from USGS 25368 (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (D). TYPE LOCALITY.—Petersburg, Virginia (Yorktown For- mation). Genus Chrysallida Carpenter, 1856 Chrysallida beaufortensis, new species PLATE 47: FIGURE 4 DIAGNOSIS.—Shell large, stout, early whorls decollated in all material, postnuclear whorls very slightly rounded and strongly squarely shouldered, spiral sculpture consists of four strong low cords. The first cord is at the summit. Cords separated by impressed lines. Juncture of axial ribs and spiral cords form small tubercules on all cords. Spaces enclosed by the axial ribs and spiral cords are deep round pits; suture constricted and rendered very conspicuous by the shouldered summit of the whorls. Aperture elongate oval, columella stout, vertical. Parietal wall glazed by thin callus. Outer lip gently curved and rendered wavy by the external spiral cords. DISCUSSION.—This species differs from Chrysallida semi- nuda (C.B. Adams, 1839) in having a more elongate aper- ture and stronger axial sculpture. This species has a more rounded aperture, less strong spiral cords, and is less elon- gate than Chrysallida stimpsoni Bartsch, 1955. FIGURED SPECIMEN.—USNM 204121 from USGS 25369, holotype, height 2.9 mm (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (E). TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25369, section 5, unit E. Chrysallida auroraensis, new species PLATE 47: FIGURE 8 DIAGNOSIS.—Shell elongate ovate, moderately large, ax- ial ribs not stronger than spiral cords, particularly in later whorls, 4 spiral cords between the sutures of later whorls, suture deeply channeled, base umbilicated, basal spiral cords strong. Axial ribs only slightly expressed after the fourth whorl, aperture oval and somewhat angulated pos- teriorly, columella is slightly curved with the edges reflected and with a strong fold at its insertion. Outer lip is gently curved and rendered wavy by the external spiral cords. DISCUSSION.—This species differs from Chrysallida gran- ulata (H.C. Lea, 1843) in being less elongate and in having a heavier shell. Warmke and Abbott (1961:148, pl. 26f) recorded Odostomia {Chrysallida) gemmulosa (C.B. Adams, 1850) from the Holocene of the West Indies. It is much more elongate and more strongly sculptured than C. auro- raensis. Recorded from the Holocene of the Atlantic Coast of the United States to the West Indies (Warmke and Abbott, 1961:148, pl. 26e) is Odostomia {Chrysallida) semi- nuda (C.B. Adams, 1839), which differs from C. auroraensis in having much more deeply channeled spiral lines and a less rounded base on the lower part of the body whorl. NUMBER 61 183 FIGURED SPECIMEN.—USNM 204122 from USGS 25361, holotype, height 3.5 mm (SEM photograph). OccuRRENCE.^This species is recorded from section 2 (E). TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25361, section 2, unit E. Genus Orinella Dall and Bartsch, 1904 Orinella beaufortensis, new species PLATE 46: FIGURE 8 DIAGNOSIS.—Shell elongate-conic, suture slightly im- pressed, whorls slightly rounded and periphery base rounded, narrowly umbilicated. Aperture broadly oval, col- umella with a single strong fold, which gives it a twisted appearance. Outer lip flaring. DISCUSSION.—This species is shorter, broader, with a stronger fold on the columella and having a more flaring outer lip than Orinella pliocena Bartsch, 1955. FIGURED SPECIMEN.—USNM 204120 from USGS 25368, holotype, height 2.7 mm (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (0). TYPE LOCALITY.—Lee Creek Mine, Beaufort County, North Carolina, USGS 25368, section 5, unit D. Genus Pyrgiscus Philippi, 1841 Pyrgiscus daedaleum (Lea) PLATE 47: FIGURE 6 Cerithium daedaleum Lea, 1843a: 11; 1846:269, pl. 37: fig. 91. DISCUSSION.—This species was not recorded by Gardner (1948) or by Bartsch (1955). FIGURED SPECIMEN.—USNM 204124 from USGS 25366 (SEM photograph). OCCURRENCE.—This species is recorded from section 5 (B). TYPE LOCALITY.—Petersburg, Virginia (Yorktown For- mation). Pyrgiscus sp. PLATE 47: FIGURE 7 DISCUSSION.—This Pyrgiscus specimen is similar to speci- mens of Pyrgiscus daedaleum (H. C. Lea) but differs in having a much more squarely shaped aperture. The figured speci- men is somewhat worn. FIGURED SPECIMEN.—USNM 204125 from USGS 25368. OCCURRENCE. (B). -This species is recorded from .section 5 Genus Turbonilla Risso, 1826 Turbonilla abrupta Bush PLATE 47: FIGURE 5 Turbonilla abrupta Bush, 1899:168, pl. 8: fig. 4. DISCUSSION.—This species was not recorded by Gardner (1948). It is listed by Warmke and Abbott (1961:149, pl. 26c) from the West Indies (Holocene). FIGURED SPECIMEN.—USNM 204123 from USGS 25367 (SEM photograph). OCCURRENCE.—This species is recorded from sections 2 (B), 3 (D), 4 (B), and 5 (B, C, D, E). TYPE LOCALITY.—St. Thomas, West Indies (Holocene). Genus Ringicula Deshayes, 1838 Ringicula semistriata d'Orbigny PLATE 47: FIGURES 1, 2 Ringicula semistriata d'Orbigny, 1853, pl. 21: figs. 17, 19. DISCUSSION.—The original figures of this species by d'Or- bigny show a specimen with much more pronounced spiral lines on the interior canal. Warmke and Abbott (1961:141, pl. 29k) reported this species from the southeastern United States Holocene and from the West Indies. Their figure shows stronger tooth processes and a heavier outer lip, with a pronounced fold in the outer lip. Our figured specimen is somewhat worn, which may account for some differences in the finer details of sculpture. This genus was not recorded by Gardner (1948). Olsson and Harbison (1953:166) recorded Ringicula {Ringiculella) floridana (Dall, 1889) from St Petersburg, Florida. This sjDecies differs from R. semistriata in having strong spiral grooving over the whole shell. FIGURED SPECIMEN.—USNM 204126 from USGS 25369 (SEM photograph). OCCURRENCE.—This species is found at section 5 (E). TYPE LOCALITY.—"La hemos hallado en la arena traida de La Jamaica por M. de Cande" (d'Orbigny, 1842) (Ja- maica). Genus Acteocina Gray, 1847 Acteocina candei (d'Orbigny) PLATE 47: FIGURE 3 Bulla cflTirfei d'Orbigny, 1841(1):128, pl. 4bis: figs. 1, 4. Acteocina candei (d'Orbigny).—Olsson and Harbison, 1953:160, pl. 25; figs. 7, 7a, 7b. 184 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY DISCUSSION.—This species shows considerable variation with regard to the height of the whorls and the flaring of the lip. Gardner (1948:278-279, pl. 38: figs. 5, 6) reported a subspecies Acteocina canaliculata vaughani Gardner, 1948, from Neills Eddy Landing, Waccamaw Formation, North Carolina. Olsson and Harbison (1953:159, 160) recorded A. canaliculata (Say, 1827) from Fort Thompson and A. candei (d'Orbigny, 1841) from St. Petersburg, Florida. FIGURED SPECIMEN.—USNM 204127 from USGS 25367 (SEM photograph). OCCURRENCE.—This species is found at sections 1 (E), 2 (D), 4 (D, E), and 5 (B, C, D, E). ORIGINAL LOCALITIES. "NOUS avons trouve cette espece dans le sable de Cuba rapporte par M. de la Sagra, et dans celui de la Guadeloupe, de Saint Thomas et de la Jamaique, recueilli par M. Ferdinand de Cande" (d'Orbigny, 1842:129) (Cuba, Guadeloupe, Saint Thomas, and Ja- maica). Literature Cited Abbou, R.T. 1954. American Seashells. xiv -I- 541 pages, 100 figures, 40 plates. Princeton, New Jersey: D. Van Nostrand Company, Inc. 1974. American Seashells. Second edition, 663 pages, 6405 figures, 24 plates. New York: Yan Nostrand Reinhold Company. Akers, W.H. 1972. Planktonic Foraminifera and Biostratigraphy of Some Neogene Fomations, Northern Florida and Atlantic Coastal Plain. Tulane Studies Geology and Paleontology, 9: 139 pages. Anonymous 1855a. Fossils of South Carolina; by M. Tuomey and F.S. Holmes, No. 1, 8 pp., 4to, with 2 4to lithographic plates [Review]. American Journal of Science and Arts, series 2, 19:452. 1855b. Fossils of South Carolina; by M. Tuomey and F.S. Holmes. Charleston, S.C, 1855. John Russell [Review of numbers 2-6]. American Journal of Science and Arts, series 2, 20:301-302. 1856. Fossils of South Carolina; by M. Tuomey and F.S. Holmes, 4to, Charleston, S.C. 1856 [Review of numbers 7 and 8]. American Journal of Science and Arts, series 2, 22:453. Arx, W.S., von, D.F. Bumpus, and W.S. Richardson 1955. On the Fine-structure of the Gulf Stream Front. Deep-Sea Re- search, 3:46-65. Bailey. R.H. 1977. 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Descriptions of Marine Shells, Recently Discovered on the Coast ofthe United Stales, fournal of the Academy of Natural Sciences of Philadelphia, first series, 5(2):207-221. [Published in February 1826 according to Nolan, 1913.] 1830. American (Conchology or Descriptions of the Shells of North America Illustrated by Coloured Figures from Original Drawings Executed from Nature, parts 1-7: unnumbered pages, 68 plates. Indiana: New-Harmony. Schumacher, CF. 1817. Essai d'un nouveau syst'eme des habitations des vers lestaces. 287 pages, 22 plates. Copenhagen. Smith, Maxwell 1938. Further Notes upon Tertiary and Recent Mollusks from Florida, with Description of New .Species. TheNautilus, 51(3):88-91, plate 6. Sowerby, G.B. 1833. Characters of New Species of Mollusca and Conchifera, Collected by Mr. Cuming. Proceedings of the Zoological Society of London, 1833:16-22. 1835. On New Species of Pecten and Xylophaga. Proceedings of the Zoological Society, 1835:109-1 10. Stenzel, H.B. 1971. Oysters. In R.C. Moore et al.. Treatise on Invertebrate Paleontology, N(3), 6(Mollusca):953-l 197. Stimpson, W. 1851. Shells of New England: A Revision ofthe Synonomy ofthe Testaceous Mollusks of New England. 56 pages, 2 plates. Boston: Phillips, Sampson and Co. 1858. [Review of] Naturhistoriske Bidrag til en Belkrivelle af Gronland; af J. Reinhardt, J. C Schiodte, O. A. L. Morch, C F. Lutken,J. Lange, H. Rink, 8 vo, pamph., pp. 172, with map. Copenhagen, 1857. American Journal of Science, second series, 25:124-126. Tryon, G.W. 1883. Marine Univalves. Manual of Conchology, series 1, 5:179, plate 58. 1886. Marine Univalves. Manual of Conchology, series 1, 8:129, plate 39. Tucker, H.L See Tucker-Rowland, H.l. Tucker-Rowland, H.L 1934. Some Atlantic Coast Tertiary Pectinidae. The American Midland Naturalist, 15(5):612-621. 1936. The Atlantic and Gulf Coast Tertiary Pectinidae of the United States. The American Midland Naturalist, 17(2):471-490. 1938. The Atlantic and Gulf Coast Tertiary Pectinidae of the United States, Section 111: Systematic Descriptions. Memoires du Musee Royal D'Histoire Naturelle de Belgique, series 10, fasc. 13:76 pages, 6 plates. Tuomey, M., and F.S. Holmes 1855. Pleiocene Fossils of South-Carolina. Pages 1-30, plates 1-12. Charleston, S.C: Russell and Jones. 1856. Pleiocene Fossils of South-Carolina. Pages 31-152, plates 13-30. Charleston, S.C: Russell and Jones. Valentine, P.C. 1971. Climatic Implication of a Late Pleistocene Ostracode Assemblage from Southeastern Virginia. United States Geological Survey Profes- sional Paper, 638-D: 28 pages. Walford, L.A., and R.L Wicklund 1968. Monthly Sea Temperature Structure from the Florida Keys to Cape Cod. American Geographical Society Serial Atlas ofthe Marine Environment, folio 15. Waller, T.R. 1969. The Evolution ofthe Argopecten gibbus Stock (Mollusca: Bivalvia), with Emphasis on the Tertiary and Quaternary Species of Eastern North America, yowrna/ of Paleontology, The Paleontological Society Memoir, 3: 125 pages, 8 plates. Ward, L.W., and B.W. Blackwelder 1975. Chesapecten a New Genus of Pectinidae (Mollusca:Bivalvia) from the Miocene and Pliocene of Eastern North America. United States Geological Survey Professional Paper, 861: 24 pages, 7 plates, 2 figures, 3 tables. 1980. Stratigraphic Revision of Upper Miocene and Lower Pliocene beds of the Chesapeake Group—Middle Atlantic Coastal Plain. United States Geological Survey Bulletin, 1482-0: 61 pages. Warmke, G.L., and R.T. Abbott 1961. (Caribbean Seashells: A Guide to the Marine Mollusks of Puerto Rico and Other West Indian Islands, Bermuda and the Lower Florida Keys. X -(- 348 pages, 44 plates. Narberth, Pennsylvania: Living- ston Publishing Company. Wells, H.W., and I.E. Gray 1960. Some Oceanic Sub-tidal Oyster Populations. Nautilus, 73(4): 139- 146. Woodring, W.P. 1928. Miocene Mollusks from Bowden, Jamaica, Part II: Gastropods and Discussion of Results. Carnegie Institution of Washington [Pub- lication] 385: 564 pages, 3 figures, 40 plates. Plates 190 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 1 1, 2. Nucula taphria Dall, USNM 203878 from USGS 25366, right valve, length 2.3 mm: 1, interior view; 2, exterior view. 3, 4. Nuculana acuta (Conrad), USNM 203880 from USGS 25368, right valve, length 6.0 mm: 3, exterior view; 4, interior view. 5, 6. Nuculana acuta (Conrad), USNM 203881 from USGS 25368, left valve, length 8.2 mm: 5, exterior view; 6, interior view. 7, 8. Nucula proxima Say, USNM 203877 from USGS 25366, right valve, length 9.0 mm: 7, exterior view; 8, interior view. 9, 10. Nucula pilkeyi, new species, holotype, USNM 203879 from USGS 25368, right valve, length 5.7 mm: 9, interior view, 10, exterior view. 11, 12. Anadara aequicostata (Conrad), USNM 203882 from USGS 25364, right valve, length 50.4 mm: 11, interior view; 12, exterior view. NUMBER 61 ■ry 'tt(Kt^'^' x.^ 1^^ 11 192 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 2 1, 2. Anadara aequicostata (Conrad), USNM 203883 from USGS 25364, right valve, length 37.5 mm: 1, exterior view; 2, interior view. 3, 4. Noetia limula (Conrad), USNM 203884 from USGS 25364, right valve, length 63.9 mm: 3, exterior view; 4, interior view. 5, 6. Quadrilatera adamsi (Dall), USNM 203885 from USGS 25368, right valve, length 13.2 mm: 5, exterior view; 6, interior view. 7, 8. Glycymeris americana (Defrance), USNM 203886 from USGS 25364, left valve, length 102.6 mm: 7, exterior view; 8, interior view. NUMBER 61 193 1' !' t 'Ik ■'ill # ' fe » 5#l^-' mmB ^ i i t i!ii'?J*^' 194 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 3 1, 2. Glycymeris sp., USNM 203890 from USGS 25366, left valve, length 18.8 mm: 1, interior view; 2, exterior view. 3. Glycymeris arata (Conrad), USNM 203887 from USGS 25367, interior view of right valve, length 21.2 mm. 4, 5. Glycymeris arata (Conrad), USNM 203888 from USGS 25366, right valve, length 11.2 mm: 4, exterior view; 5, interior view. 6, 7. Glycymeris sloani, new species, holotype, USNM 203889 from USGS 25367, left valve, length 6.6 mm: 6, interior view; 7, exterior view. NUMBER 61 95 196 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 4 1, 2. Mytilus sp. aff. M. edulis Linnaeus, USNM 203891 from USGS 25366, left valve, length 9.7 mm: 1, exterior view; 2, interior view. 3, 4. Crenella decussata (Montagu), USNM 203893 from USGS 25367, right valve, length 3.1 mm: 3, exterior view; 4, interior view. 5, 6. (Crenella decussata (Montagu), USNM 203894 from USGS 25366, right valve, length 3.1 mm: 5, exterior view; 6, interior view. 7, 8. Musculus lateralis (Say), USNM 203895 from USGS 25367, right valve, length 3.0 mm: 7, exterior view; 8, interior view. 9. Brachidontes sp., USNM 203892 from USGS 25367, exterior view of left valve, length 5.4 mm. 10, 11. Modiolus sp. cf. M. modiolus (Linnaeus), USNM 203896 from USGS 25364, right valve, length 52.2 mm: 10, interior view; 11, exterior view. 12, 13. Glycymeris hummi, new species, holotype, USNM 204136 from USGS 26123, left valve, length 65.1 mm: 12, interior view; 13, exterior view. NUMBER 61 197 198 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 5 1-3. Lithophaga yorkensis Olsson, USNM 203897 frotn USGS 25369, length 9.6 mm: 1. articulated specimen in Mercenaria valve; 2, interior view of right valve; 3, exterior view of right valve. 4. Leptopecten? auroraensis, new species, holotype, USNM 203898 from USGS 25357, exterior view of left valve, length 11.7 mm. 5, 6. Leptopecten? auroraensis, new species, USNM 203899 from USGS 25357, right valve, length 13.4 mm: 5, interior view; 6, exterior view. 7-9. Argopecten vicenarius vicenarius (Conrad), USNM 203900 from USGS 25364, right valve, length 45.6 mm: 7, interior view; 8, exterior view; 9, anteroventral view. NUMBER 61 199 t -^--m'^ '^<:''-^ -j^ 200 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 6 Carolinapecten eboreus (Conrad) 1. USNM 203901 from USGS 25364, exterior sculpture and ribbing on ventral margin of left valve, length of figured portion 40.6 mm. 2, 3. USNM 203902 from USGS 25362, interior hinge area and exterior dorsal margin of left hinge, length 67.2 mm. 4-6. USNM 203903 from USGS 25360, length of specimen 109.6 mm: 4, dorsal view of articulated specimen; 5, exterior view of right valve; 6, exterior view of left valve. 7. USNM 203904 from USGS 25364, exterior sculpture and ribbing on ventral margin of right valve, length of figured portion 44.0 mm. 8, 9. USNM 203905 from USGS 25364, right valve: 8, exterior dorsal margin; 9, interior hinge area, hinge length 65.7 mm. NUMBER 61 201 202 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 7 1, 2. Pododesmus fragosus (Conrad), USNM 203909 from USGS 25362, right valve, length 47.6 mm: 1, interior view; 2, exterior view. 3, 4. Plicatula marginata Say, USNM 203906 from USGS 25368, left valve, length 19.0 mm: 3, interior view; 4, exterior view. 5. Plicatula marginata Say, USNM 203907 from USGS 25368, interior view of left valve, length 17.1 mm. 6-8. Anomia simplex (d'Orbigny), USNM 203908 from USGS 25362, left valve, length 37.8 mm: 6, interior oblique-ventral view; 7, exterior view; 8, interior view. 9-11. (Carolinapecten eboreus (Conrad), neoholotype, USNM 204134 from USGS 25724A, length of specimen 56.2 mm (right valve convexity 7.8 mm, left valve convexity 9.4 mm): 9, exterior view of right valve; 10, exterior view of left valve; 11, dorsal view of articulated valves. NUMBER 61 203 10 204 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 8 1. Crassostrea virginica auroraensis, new subspecies, UoNM 203910 from USGS 25364, interior view of right valve, height 179.0 mm. 2. Crassostrea virginica auroraensis, new subspecies, USNM 203912 from USGS 25364, interior view of right valve, height 123.7 mm. 3, 4. Crassostrea virginica auroraensis, new subspecies, holotype, USNM 203911 from USGS 25364, left valve, height 117.6 mm: 3, anterior profile; 4, interior view. 5, 6. Conradostrea lawrencei, new species, holotype, USNM 203913 from USGS 25364, left valve, height 69.3 mm: 5, exterior view; 6, interior view. NUMBER 61 205 206 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 9 1, 2. (Conradostrea lawrencei, new species, USNM 204127 from USGS 25364, right valve, height 90.0 mm: 1, interior view; 2, exterior view. 3, 4. Parvilucina multilineata (Tuomey and Holmes), USNM 203915 from USGS 25368, left valve, length 4.1 mm: 3, interior view; 4, exterior view. 5, 6. Parvilucina multilineata (Tuomey and Holmes), USNM 203916 from USGS 25368, right valve, length 4.4 mm: 5, exterior view; 6, interior view. 7, 8. Stewartia anodonta floridana (Conrad), USNM 203914 from USGS 25364, left valve, length 32.8 mm: 7, interior view; 8, exterior view. NUMBER 61 207 208 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 10 1, 2. Bellucina waccamawensis (Dall), USNM 203917 from USGS 25360, right valve, length 8.3 mm: 1, exterior view; 2, interior view. 3, 4. Bellucina waccamawensis (Dall), USNM 203918 from USGS 25369, right valve, length 6.3 mm: 3, exterior view; 4, interior view. 5, 6. Callucina keenae (Chavan), USNM 203919 from USGS 25364, left valve, length 14.1 mm: 5, exterior view; 6, interior view. 7, 8. Cavilinga trisulcata (Conrad), USNM 203920 from USGS 25368, right valve, length 5.2 mm: 7, exterior view; 8, interior view. 9, 12. Phlyctiderma heroni, new .species, holotype, USNM 203921 from USGS 25367, right valve, length 12.1 mm: 9, interior view; 12, hinge view (length of hinge 11.4 mm). 10. Phlyctiderma heroni, new species, USNM 203922 from USGS 25367, exterior view of right valve, length 7.3 mm. 11. Phlyctiderma heroni, new species, USNM 203923 from USGS 25367, hinge view (length 10.0 mm) of left valve. 10. NUMBER 61 209 210 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 1 1 1-3. Diplodonta acclinis (Conrad), USNM 203924 from USGS 25366, length of articulated valves, length 17.3 mm: 1, interior view of left valve; 2, exterior view of left valve; 3, interior view of right valve. 4, 6. Phlyctiderma heroni, new species, USNM 203923 from USGS 25367, left valve, length 10.0 mm: 4, exterior view; 6, interior view. 5. Phlyctiderma heroni, new species, USNM 203922 from USGS 25367, profile of left valve from articulated specimen, height 7.1 mm. 7-10. Diplodonta berryi McGavock, USNM 203925 from USGS 25370. articulated specimen, length 17.9 mm: 7, interior view of left valve; 8, exterior view of left valve; 9, interior view of right valve; 10, exterior view of right valve. NUMBER 61 211 212 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 12 1, 3. Chama gardnerae Olsson and Harbison, USNM 203926 from USGS 25367, left valve, length 17.1 mm: 1, exterior view; 2, interior view. 2. Chama gardnerae Olsson and Harbison, USNM 203927 from USGS 25367, interior view of right valve, length 12.2 mm. 4, 6. Bornia triangula Dall, USNM 203931 from USGS 25366, right valve, length 8.5 mm: 4, interior view; 6, exterior view. 5. Bornia triangula Dall, USNM 203932 from USGS 25366, interior view of left valve, length 9.0 mm. 7, 8. Mysella beaufortensis, new species, holotype, USNM 203930 from USGS 25367, right valve: 7, exterior view; 8, interior view. 9, 10. Aligena striata Lea, USNM 203929 from USGS 25367, right valve, length 12.4 mm: 9, interior view; 10, exterior view. 11, 12. Sportella waccamawensis Gardner, USNM 203928 from USGS 25367, right valve, length 16.1 mm: 11, exterior view; 12, interior view. NUMBER 61 213 214 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 13 1, 2. Anisodonta Carolina Dall, USNM 203933 from USGS 25366, right valve, length 6.3 mm: 1, interior view; 2, exterior view. 3, 4. Anisodonta Carolina Dall, USNM 203934 from USGS 25366, left valve, length 6.0 mm: 3, interior view; 4, exterior view. 5, 6. Ensitellops elongata Olsson and Harbison, USNM 203935 from USGS 25367, left valve, length 9.0 mm: 5, exterior view; 6, interior view. 7, 8. Pleuromeris auroraensis, new species, USNM 203941 from USGS 25367, left valve, length 4.5 mm: 7, interior view; 8, exterior view. 9, 10. Pleuromeris auroraensis, new species, holotype, USNM 203942 from USGS 25367, right valve, length 4.6 mm: 9, interior view; 10, exterior view. 11, 12. Pleuromeris decemcostata Conrad, USNM 203940 from USGS 25368, left valve, length 5.8 mm: 11, exterior view; 12, interior view. NUMBER 61 215 216 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 14 1, 2. Carditamera arata (Conrad), USNM 203936 from USGS 25364, right valve, length 43.1 mm: 1, exterior view; 2, interior view. 3. Carditamera arata (Conrad), USNM 203937 from USGS 25364, exterior of right valve, length 35.9 mm. 4, 5. (Cyclocardia sp. cf C. granulata (Say), USNM 203938 from USGS 25364, right valve, length 32.8 mm: 4, interior view; 5, exterior view. 6, 7. Cyclocardia sp. cf C. granulata (Say), USNM 203939 from USGS 25364, right valve, length 26.4 mm: 6, exterior view; 7, interior view. i, 10. Pteromeris perplana (Conrad), USNM 203943 from USGS 25368, right valve, length 4.2 mm: 8, exterior view; 10, interior view. 9. Pteromeris perplana (Conrad), USNM 203944 from USGS 25368, interior of left valve, length 4.5 mm. 11. Pteromeris perplana (Conrad), USNM 203945 from USGS 25368, exterior view of left valve, length 6.7 mm. NUMBER 61 217 %:t' ^ 10 218 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 15 1-4. Marvacrassatella kauffmani, new species, holotype, USNM 203950 from USGS 25362, length 89.1 mm: 1, dorsal view of articulated specimen; 2, interior view of left valve; 3, interior view of right valve; 4, exterior view of left valve. 5, 6. Erycinella ovalis Conrad, USNM 203946 from USGS 25366, right valve, length 1.4 mm: 5, exterior view; 6, interior view. NUMBER 61 219 220 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 16 1, 2. Astarte berryi Gardner, USNM 203947 from USGS 25364, left valve, length 27.8 mm: 1, exterior view; 2, interior view. 3, 4. Astarte concentrica Conrad, USNM 203948 from USGS 25364, left valve, length 28.4 mm: 3, interior view; 4, exterior view. 5. Astarte concentrica Conrad, USNM 203949 from USGS 25364, interior view of right valve, length 26.2 mm. 6, 7. (Crassinella lunulata (Conrad), USNM 203953 from USGS 25367, left valve, length 6.4 mm: 6, exterior view; 7, interior view. 8. Crassinella lunulata (Conrad), USNM 2041 33 from USGS 25367, exterior view of right valve, length 6.0 mm. 9. (Crassinella dupliniana (Dall), USNM 203951 from USGS 25366, interior view of left valve, length 2.0 mm. 10. Crassinella dupliniana (Dall), USNM 203952 from USGS 25366, exterior view of right valve, length 2.3 mm. NUMBER 61 221 222 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 17 1. (Crassinella johnsoni, new species, U.SNM 203956 from USGS 25362, interior view of left valve, length 2.2 mm. 2. (Crassinella johnsoni, new species, USNM 203955 from USGS 25367, exterior view of right valve, length 2.2 mm. 3, 4. Laevicardium sublineatum (Conrad), USNM 203957 from USGS 25364, right valve, length 25.6 mm: 3, interior view; 4, exterior view. .5, 6. Dinocardium robustum hazeli, new subspecies, holotype, USNM 203958 from USGS 25364, right valve, length 128.6 nmi: 5, interior view; 6, exterior view. 7. Mulinia lateralis (.Say), USNM 203959 from USGS 25368, hinge view of right valve, length (of illustrated portion) 9.0 mm. 8, 9. Mulinia lateralis (Say), USNM 203960 from USGS 25368, left valve, length 11.9 mm: 8, interior view; 9, exterior view. NUMBER 61 223 224 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 18 1, 2. Sptsula solidissima (Dillwyn), USNM 203965 from USGS 25364, left valve, length 105.7 mm: 1, interior view; 2, hinge view. 3, 4. Spisula similis (Say), young specimen, USNM 203962 from USGS 25368, right valve, length 18.3 mm: 3, interior view; 4, exterior view. 5, 6. Spisula similis (Say), young specimen, USNM 203963 from USGS 25364, left valve, length 43.2 mm: 5, interior view; 6, exterior view. 7, 8. Spisula similis (Say), adult specimen, USNM 203964 from USGS 25364, left valve, length 64.3 mm: 7, interior view; 8, hinge view. NUMBER 61 225 226 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 19 1-3. Raeta plicatella (Lamarck), USNM 203966 from USGS 25363, length 46.6 mm: 1, exterior view of right valve; 2, interior view of left valve; 3, interior view of right valve. 4, 5. Rangia clathrodonta (Conrad), USNM 203961 from USGS 25364, left valve, length 49.0 mm: 4, exterior view; 5, interior view. 6, 7. Ensis directus (Conrad), USNM 203967 from USGS 25364, right valve, length 72.3 mm: 6, interior view; 7, exterior view. 8. Tellina agilis Stimpson, USNM 203968 from USGS 25367, exterior view of right valve, length 10.5 mm. 9. Tellina agilis Stimpson. USNM 203969 from USGS 25367, interior view of right valve, length 8.6 mm. 10. Tellina agilis Stimpson, USNM 203970 from USGS 25367, interior view of left valve, length 10.8 mm. NUMBER 61 227 228 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 20 1, 2. Macoma holmesii Dall, USNM 203971 from USGS 25648, left valve, length 40.7 mm: 1, exterior view; 2, interior view. 3, 4. Macoma holmesii Dall, kUSNM 203972 from USGS 25648, right valve, length 28.7 mm: 3, interior view; 4, exterior view. 5, 6. Semele bellastriata (Conrad), USNM 203974 from USGS 25360, right valve, length 16.4 mm: 5, interior view; 6, exterior view. 7, 8. Donax fossor .Say, USNM 203973 from USGS 25369, left valve, length 8.7 mm: 7, interior view; 8, exterior view. 9. Abra aequalis (.Say), USNM 203975 from USGS 25369, interior view of left valve, length 10.5 mm. 10, 11. Abra aequalis (Say), USNM 203976 from USGS 25369, right valve, length 12.0 mm: 10, interior view; I 1, exterior view. NUMBER 61 229 230 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 21 1, 3, 5. Cumingia tellinoides (Conrad), USNM 203977 from USGS 25369, left valve, length 13.2 mm: 1, exterior view; 3, interior view; 5, detail of hinge area. 2, 4, 6. (Cumingia tellinoides (Conrad), USNM 203978 from USGS 25369, right valve, length 14.4 mm: 2. exterior view; 4, detail of hinge area; 6, interior view. 7-9. (Corbicula densata (Conrad), USNM 203980 from USGS 25364, length of articulated valves 53.3 mm: 7, interior view of right valve; 8, exterior view of left valve; 9, interior view of left valve. 10, 11. Tagelus plebeius carolinensis (Conrad), USNM 203979 from USGS 25360, right valve, length 92.7 mm: 10, interior view; 1 1, exterior view. NUMBER 61 23: 232 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 22 1, 2. Transennella stimpsoni Dall, USNM 203982 from USGS 25367, right valve, length 9.6 mm: 1, exterior view; 2, interior view. 3. Transennella stimpsoni Dall, USNM 203983 from USGS 25367, interior view of left valve, length 7.3 nmi. 4, 5. Gouldia metastriatum (Conrad), USNM 203981 from USGS 25368, right valve, length 10.0 mm: 4, interior view; 5, exterior view. 6. Pitar chioneformis (Gardner), USNM 203984 from USGS 25370, interior view of left valve, length 29.1 mm. 7, 8. Pitar chioneformis (Gardner), USNM 203985 from USGS 25370, right valve, length 28.5 mm: 7, exterior view; 8, interior view. 9, 10. Gemma magna majorina Gardner, USNM 203987 from USGS 25368, right valve, length 4.8 mm: 9, exterior view; 10, interior view. NUMBER 61 233 234 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 23 1, 2. Macrocallista greeni, new species, holotype, USNM 203986 from USGS 25362, left valve, length 78.6 mm: 1, exterior view; 2, interior view. 3, 4. Chione grus (Holmes), USNM 203988 from USGS 25357, left valve, length 11.6 mm: 3, interior view; 4, exterior view. 5. (Chione grus (Holmes), USNM 203989 from USGS 25357. interior view of right valve, length 10.7 mm. 6. Mercenaria mercenaria (Linnaeus), USNM 203992 from USGS 25364, interior view of right valve, length 58.0 mm. 7, 8. Chione cribraria (Conrad), USNM 204130 from USGS 25648, left valve, length 26.7 mm: 7, exterior view; 8, interior view. NUMBER 61 235 ' '""^^^iiat. .i.^^^'^'e 236 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 24 1. Mercenaria mercenaria (Linnaeus), USNM 203992 from USGS 25364, exterior view of right valve, length 58.0 mm. 2, 3, 5. Mercenaria permagna (Conrad), USNM 203990 from USGS 25367, articulated specimen, length 122.0 mm, height 90.3 mm: 2, dorsal view; 3, exterior view of right valve; 5, posterior view. 4. Mercenaria permagna (Conrad), USNM 203991 from USGS 25367, interior view of right valve, length 1 18.9 mm. 6. 7. Petricola pholadiformis Lamarck, USNM 204131 from USGS 25648, left valve, length 41.6 mm: 6, interior view; 7, exterior view. NUMBER 61 237 238 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 25 1, 3. Petricola pectorosa (Conrad), USNM 203993 from USGS 25367, right valve, length 18.0 mm: 1, exterior view; 3, interior view. 2. Petricola pectorosa (Conrad), USNM 203994 from USGS 25367, interior view of left valve, length 17.9 mm. 4, 5. Mya arenaria Linnaeus, USNM 203995 from USGS 25364, right valve, length 56.1 mm: 4, interior view; 5, exterior view. 6, 7. Paramya subovata (Conrad), USNM 203996 from USGS 25367, left valve, length 9.9 mm: 6, interior view; 7, exterior view. 8. Paramya subovata (Conrad), USNM 203997 from USGS 25367, interior of right valve, length 10.0 mm. NUMBER 61 239 240 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 26 1, 2. Sphenia dubia (Lea), USNM 203998 from USGS 25369, left valve, length 7.8 mm: 1, exterior view; 2, interior view. 3, 6. Caryocorbula contracta (Say), USNM 203999 from USGS 25366, right valve, length 8.7 mm: 3, exterior view; 6, interior view. 4, 5. (Caryocorbula contracta (Say), USNM 204000 from USGS 25366, left valve, length 9.2 mm: 4, exterior view; 5, interior view. 7, 8. (Caryocorbula auroraensis, new name, USNM 204001 from USGS 25368, right valve, length 13.5 mm: 7, exterior view; 8, interior view. NUMBER 61 241 242 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 27 1, 2. Caryocorbula auroraensis, new name, USNM 204002 from USGS 25368, left valve, length 7.4 mm: 1, exterior view; 2, interior view. 3. (Caryocorbula auroraensis, new name, USNM 204003 from USGS 25368, exterior view of right valve, length 8.2 mm. 4-6. Gastrochaena hians (Gmelin), USNM 204004 from USGS 25369, length of specimen 4.6 mm: 4, specimen in valve of Mercenaria carolinensis; 5, interior view of right valve; 6, exterior view of right valve. 7, 8. Pandora tuomeyi Gardner and Aldrich, USNM 204007 from USGS 25367, right valve, length 14.3 mm: 7, exterior view; 8, interior view. 9. (Cyrtopleura sp., USNM 204006 from USGS 25339, exterior view of right valve, length (broken) 71.0 mm. NUMBER 61 243 '^i-^f.- ■''^ -': 8 244 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 28 1. 2. Panopea floridana (Heilprin), USNM 204005 from USGS 25362, left valve, length 166.4 mm: 1, exterior view; 2, interior view. 3, 4. Cochlodesma emmonsii, new species, USNM 204008 from USGS 25363, right valve, length 27.4 mm: 3, exterior view; 4, interior view. 5, 6. (Cochlodesma emmonsii, new species, USNM 204009 from USGS 25363, left valve, length 27.0 mm: 5, exterior view; 6, interior view. NUMBER 61 245 i "^^: ■;>' -'.., \ 246 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 29 1, 2. Verticordia emmonsii Conrad, USNM 204014 from USGS 25366, right valve, length 4.5 mm: 1, exterior view; 2, interior view. 3, 4. Verticordia lockei, new species. USNM 204012 from USGS 25368, right valve, length 6.7 mm: 3, exterior view; 4, interior view. 5, 6. Verticordia lockei, new species, holotype, USNM 204013 from USGS 25367, right valve, length 6.8 mm: 5, exterior view; 6, interior view. 7,8. Thracia brioni, new species, USNM 204010 from USGS 25367, right valve, length 9.1 mm: 7, interior view; 8, exterior view. 9, 10. Thracia brioni, new species, holotype, USNM 204011 from USGS 25366, right valve, length 6.1 mm: 9, exterior view; 10, interior view. 11. Cadulus quadridentatus (DaW), USNM 204015 from USGS 25366, oblique view of apex of specimen, apical diameter 0.7 mm. 12. (Cadulus quadridentatus (Dall), USNM 204016 from USGS 25366, lateral view of specimen, height 8.8 mm. 11. NUMBER 61 247 248 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 30 1, 2. Diodora nucula (Dall), USNM 204017 from USGS 25368, length 4.3 mm: 1, dorsal view; 2, ventral view. 3. Diodora nucula (Dall), USNM 204018 from USGS 25368, lateral view, height 2.3 mm. 4, 5. Diodora auroraensis, new species, holotype, USNM 204019 from USGS 25362, length 25.3 mm: 4, ventral view; 5, dorsal view. 6, 7. Diodora pamlicoensis, new species, holotype, USNM 204020 from USGS 25362, length 30.2: 6, ventral view; 7, dorsal view. 8, 9. Calliostoma philanthropum pontoni Mansfield, USNM 204021 from USGS 25370, height 22.1 mm, maximum diameter 19.6 mm: 8, apertural view; 9, umbilical view. NUMBER 61 249 250 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 31 1-3. Arene pergemma (Gardner), USNM 204022 from USGS 25366, height 3.9 mm, maximum diameter 5.1 mm: 1, apertural view; 2, umbilical view; 3, apical view. 4. Arene pergemma (Gardner), USNM 204023 from USGS 25366, apical view showing color pattern, maximum diameter 4.0 mm. 5. Rissoa geraea Dall, USNM 204025 from USGS 25367, apertural view, height 3.1 mm. 6. Littorina carolinensis Conrad, USNM 204024 from USGS 25368, apertural view, height 2.3 mm. 7-9. Teinostoma goniogyrus Pilsbry and McGinty, USNM 204026 from USGS 25359, maximum diameter 2.2 mm: 7, apical view; 8, apertural view; 9, umbilical view. NUMBER 61 251 252 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 32 1-3. Teinostoma beaufortensis, new species, holotype, USNM 204027 from USGS 25367, maximum diam- eter 1.6 nmi: 1, apertural view; 2, apical view; 3, umbilical view. 4-6. Teinostoma smirkon Gardner, USNM 204028 from USGS 25367, maximum diameter 1.5 mm: 4, apertural view; 5. apical view; 6, umbilical view. 7-9. Teinostoma tectispira Pilsbry, USNM 204029 from U.SGS 25367, maximum diameter 1.7 mm: 7, apertural view; 8, apical view; 9, umbilical view. NUMBER 61 253 254 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 33 1-3. (Cyclostremiscus obliquestriatus (Lea), USNM 204030 from USCiS 25367, maximum diameter 2.6 mm: 1, apertural view; 2, apical view; 3, umbilical view. 4-6. Didianema carolinae (Gardner), USNM 204031 from USGS 25366, maximum diameter 1.4 mm: 4, apertural view; 5, umbilical view; 6, apical view. NUMBER 61 255 256 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 34 1-3. Macromphalina hanseni, new species, holotype, USNM 204032 from USGS 25367, maximum diameter 1.4 mm: 1, apical view; 2, umbilical view; 3, apertural view. 4-6. Macromphalina pierrot Gardner, USNM 204033 from USGS 25357, maximum diameter 2.2 mm: 4, apical view; 5, umbilical view; 6, apertural view. NUMBER 61 257 / ' ,1. I ■ ' "*■).'. ■;■•' (ft-. ,:. V' ■' N^^'brl" ■ ^'?5.'v:--^ W.K''. ^ > ^ 'v> *>* • v-^ 258 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 35 1. Turritella beaufortensis, new species, holotype, USNM 204038 from USGS 25370, apertural view, height 29.0 mm. 2. Turritella beaufortensis, new species, USNM 204039 from USGS 25366, exterior sculpture, height 14.0 mm. 3. Turritella perexilis Conrad, USNM 204040 from USGS 25366, apertural view, height 25.3 mm. 4. Turritella perexilis Conrad, USNM 204041 from USGS 25366, apertural view, height 19.6 mm. 5. Serpulorbis granifera (Say), USNM 204043 from USGS 25364, length of specimen 34.0 mm. 6. Vermicularia spirata (Philippi), USNM 204128 from USGS 25366, apertural view, height 9.2 mm. ', 8. Vermicularia spirata (Philippi), USNM 204042 from USGS 25370, lateral views, height (of figure 7) 10.7 mm. 9. (Caecum beaufortensis, new species, holotype, USNM 204034 from USGS 25367, height 3.3 mm. 10. Caecum pulchellum Stimpson, USNM 204035 from USGS 25367, height 2.6 mm. 11. Caecum imbricatum Carpenter, USNM 204036 from USGS 25367, height 4.3 mm. 12. Caecum flemingi Gardner and Aldrich, USNM 204037 from USGS 25367, height 4.7 mm. 10. NUMBER 61 259 260 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 36 1. Epitonium leai, new species, holotype, USNM 204049 from USGS 25366, apertural view, height 8.1 mm. 2. Seila adamsii (Lea), USNM 204045 from USGS 25368, apertural view, height 9.8 mm. 3. Sella adamsii (Lea), USNM 204046 from USGS 25368, apertural view, height 7.8 mm. 4. Balcis? sp., USNM 204055 from USGS 25367, apertural view, height 3.7 mm. 5. Triphora dupliniana (Olsson), USNM 204047 from USGS 25368, apertural view, height 2.4 mm. 6. Triphora dupliniana (Ols.son), USNM 204048 from USGS 25368, apertural view, height 3.3 mm. 7. Bittium podagrinum Dall, USNM 204044 from USGS 25368, apertural view, height 3.2 mm. 8. Epitonium carolinae Gardner, USNM 204050 from USGS 25368, apertural view, height 5.1 mm. 9. Epitonium carolinae Gardner, USNM 204051 from USGS 25366, apertural view, height 5.5 mm. 10. Epitonium sohli, new species, holotype, USNM 204052 from USGS 25366, apertural view, height 5.3 mm. 1 1. Epitonium sp. cf E. foliaceicostum (d'Orbigny), USNM 204053 from USGS 25369, apertural view, height 6.4 mm. 12, 13. Epitonium rupicolum (Kurtz), USNM 204054 from USGS 25368, height 7.3 mm: 12, abapertural view; 13, apertural view. 14. Epitonium fractum Dall, USNM 204132 from USGS 25339, apertural view, height 14.6 mm. NUMBER 61 261 262 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 37 1. Balcis beaufortensis, new species, holotype, USNM 204056 from USGS 25367, apertural view, height 4.5 mm. 2. Balcis biconica (Gardner), new combination, USNM 204057 from USGS 25367, apertural view, height 5.0 mm. 3. Balcis eborea (Conrad), new combination, USNM 204058 from USGS 25367, apertural view, height 5.2 nmi. 4. Eulima juncea (Gardner), new combination, USNM 204059 from USGS 25367, apertural view, height 4.7 mm. 5, 6. (Calyptraea centralis (Conrad), USNM 204060 from USGS 25368, maximum diameter 4.4 mm: 5, ventral view; 6, dorsal view. 7, 8. Crepidula aculeata (Gmelin), USNM 204062 from USGS 25362, length 27.8 mm: 7, ventral view; 8, dorsal view. 9-11. (Crucibulum lawrencei, new species, holotype, USNM 204061 from USGS 25364, maximum diameter 52.8 mm: 9, dorsal view; 10, ventral view; 1 1, lateral view. NUMBER 61 263 264 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 38 1, 2. (Crepidulafornicata (Linnaeus), USNM 204063 from USGS 25364, length 29.1 mm: 1, ventral view; 2, dorsal view. 3,4. Trivia floridana Olsson and Harbison, USNM 204065 from USGS 25339, length 15.5 mm: 3, apertural view; 4, abapertural view. 5, 6. (Crepidula plana Say, USNM 204064 from USGS 25362, length 31.3 mm: 5, dorsal view; 6, ventral view. 7, 8. Tectonatica pusilla (Say), USNM 204066 from USGS 25367, height 6.7 mm: 7, abapertural view; 8, apertural view. 9-11. Polinices duplicata (Say), USNM 204067 from USGS 25364, height 27.7 mm: 9, apical view; 10, umbilical view; 11, apertural view. 12. Lunatia heros (Say), USNM 204068 from USGS 25362, apertural view, height 22.8 mm. NUMBER 61 265 266 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 39 1, 2. Urosalpinx sp. cf. U. perrugata (Conrad), USNM 204072 from USGS 25366, height 13.0 mm: 1, abapertural view; 2, apertural view. 3, 4. Murexiella macgintyi (M. Smith), USNM 204069 from USGS 25362, height 14.8 mm: 3, abapertural view; 4, apertural view. 5, 6. Urosalpinx suffolkensis Gardner, USNM 204073 from USGS 25364, height 28.5 mm: 5, apertural view; 6, abapertural view. 7, 8. Pterorhytis conradi (Dall), USNM 204070 from USGS 25360, height 35.8 mm: 7, abapertural view; 8, apertural view. 9. Eupleura caudata (Say), USNM 204071 from USGS 25367, abapertural view, height (of broken specimen) 13.8 mm. 10, 11. Urosalpinx stimpsoni Gardner, USNM 204074 from USGS 25364, height 29.7 mm: 10, abapertural view; 1 1 apertural view. NUMBER 61 267 268 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 40 1-3. Anachis milleri Gardner, USNM 204075 from USGS 25368, height 11.9 mm: 1, profile view; 3, apertural view. 2. Anachis milleri Gardner, USNM 204076 from USGS 25366, apertural view, height 14.7 mm. 4, 5. Mitrella gardnerae ecarinata (Olsson and Harbison), USNM 204077 from USGS 25368, height 2.5 mm: 4, apertural view; 5, abapertural view. 6, 7. Mitrella gardnerae (Olsson and Harbison), USNM 204078 from USGS 25366, height 12.9 mm: 6, apertural view; 7, abapertural view. 8, 9. Nassarius chowanensis (Gardner), USNM 204083 from USGS 25362, height 9.8 mm: 8, abapertural view; 9, apertural view. 10, 11. Mitrella waccamawensis Gardner, USNM 204079 from USGS 25368, height 3.4 mm: 10, apertural view; 11, abapertural view. 12. Aesopus stearnsii (Tryon), USNM 204080 from USGS 25368, apertural view, height 4.0 mm. 13. Aesopus ithitoma (Dall), USNM 204081 from USGS 25368, apertural view, height 3.7 mm. 14. Aesopus gardnerae, new species, holotype, USNM 204082 from USGS 25367, apertural view, height 3.8 mm. 15. Nassarius granifera (Clonrad), USNM 204084 from USGS 25364, apertural view, 17.2 mm. 16, 17. Nassarius cornelliana (Olsson), USNM 204085 from USGS 25366, height 4.6 mm: 16, apertural view; 17, abapertural view. NUMBER 61 269 270 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 41 1, 2. Nassarius schizopyga? (Dall), USNM 204086 from USGS 25367, height 26.0 mm: 1, apertural view; 2, abapertural view. 3, 4. Nassarius schizopyga? (Dall), USNM 204087 from USGS 25339, height 20.5 mm: 3, apertural view; 4, abapertural view. 5. 6. Busycon spiratus pyruloides (Say), USNM 204089 from USGS 25371, height 20.5 mm: 5, abapertural view; 6, apertural view. 7. Busycon adversarius Conrad, USNM 204090 from USGS 25364, apertural view, height 187.3 mm. 8. Nassarius scalaspira? (Conrad), USNM 204088 from USGS 25339, apertural view of broken specimen, height 21.2 mm. 7. NUMBER 61 271 272 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 42 1, 2. Busycon carica (Gmelin), USNM 204091 from USGS 25364, height 193.1 mm: 1, apertural view; 2, abapertural view. 3. Busycon spiratus pyruloides (Say), USNM 204092 from USGS 25364, abapertural view of broken specimen, height 96.3 mm. 4, 5. Busycon concinnum Conrad, USNM 204093 from USGS 25370, height 69.2 mm: 4, apertural view; 5, abapertural view. NUMBER 61 273 \^\v55s?«s5aa^ 274 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 43 1, 2. Fasciolaria cronlyensis Gardner, USNM 204094 from USGS 25364, height 60.2 mm: 1, abapertural view; 2, apertural view. 3. Fasciolaria beaufortensis, new species, USNM 204095 from USGS 25364, apertural view, height 98.8 mm. 4, 5. Fasciolaria beaufortensis, new species, holotype, USNM 204096 from USGS 25362, height 82.0 mm: 4, apertural view; 5, abapertural view. 6, 8. Heilprinia caloosaensis malcolmi, new subspecies, holotype, USNM 204097 from USGS 25648, height 76.5 mm: 6, apertural view; 8, abapertural view. 7. Heilprinia caloosaensis malcolmi, new subspecies, USNM 204098 from USGS 25371, apertural view, height 48.6 mm. NUMBER 61 275 276 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 44 1. Voiutifusus typus Conrad, USNM 204102 from USGS 25364, apertural view, height 91.5 mm. 2, 3. Voiutifusus typus Conrad, USNM 204103 from USGS 25364, height 153.0 mm: 2, abapertural view; 3, apertural view. 4. Granulina ovuliformis (d'Orbigny) USNM 204107 from USGS 25368, abapertural view, height 4.4 mm. 5, 6. Oliva carolinensis (Conrad), USNM 204099 from USGS 25371, height 41.7 mm: 5, abapertural view; 6, apertural view. 7. Olivella mutica (Say), USNM 204100 from USGS 25366, apertural view, height 15.1 mm. 8, 9. Dentimargo polyspira? (Olsson and Harbison), USNM 204104 from USGS 25367, height 4.3 mm: 8, apertural view; 9, abapertural view. 10. Volvarina avena (Kiener), USNM 204108 from USGS 25366, apertural view, height 7.3 mm. 1 1. Prunum limatulum (Conrad), USNM 204105 from USGS 25366, abapertural view showing color pattern beneath exterior shell layer, height 1 1.0 mm. 12-14. Prunum limatulum (Conrad), USNM 204106 from USGS 25366, height 10.5 mm: 12, abapertural view; 13, profile of aperture; 14, apertural view. NUMBER 61 277 278 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 45 1. Granulina ovuliformis (d'Orbigny), USNM 204129 from USGS 25368, apertural view, height 4.0 mm. 2, 3. Conus adversarius Conrad, USNM 204110 from USGS 25364, height 64.7 mm: 2, abapertural view; 3, apertural view. 4, 6. Cymatosyrinx lunata (Lea), USNM 204111 from USGS 25367, height 12.6 mm: 4, apertural view (lacks part of the thin outer shell layer); 6, abapertural view. 5. (Cymatosyrinx lunata (Lea), USNM 204112 from USGS 25368, apertural view, height 7.6 mm. 7. Trigonostoma sp., USNM 204109 from USGS 25362, abapertural view, height of broken specimen 18.1 mm. 8. Vexillum wandoense (Holmes), USNM 204101 from USGS 25366, apertural view, height 6.8 mm. 9. 10. Sedilia sp. aff. 5. sedilia (Dall), USNM 204113 from USGS 25368, height 9.4 mm: 9, apertural view; 10, abapertural view. 11. Strioterebrum sp., USNM 204118 from USGS 25366, apertural view, height 14.7 mm. 12. Strioterebrum sp. cf. S. petiti Olsson, USNM 204119 from USGS 25369, view of broken specimen, height 12.6 mm. 11. NUMBER 61 279 280 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 46 2. Brachycythara reidenbachi, new species, holotype, USNM 204114 from USGS 25369, height 3.6 mm: 1, apertural view; 2, profile of aperture. 3. Glabrocythara sp., USNM 204115 from USGS 25368, apertural view, height 5.5 mm. 4. Vitricythara micromeris (Dall), USNM 204117 from USGS 25368, apertural view, height 2.3 mm. 5. Glabrocythara sp., USNM 204116 from USGS 25367, apertural view, height 5.9 mm. 6. Odostomia simplex (Lea), USNM 204118 from USGS 25369, apertural view, height 1.5 mm. 7. Odostomia turbinatus (Lea), USNM 2041 19 from USGS 25368, apertural view, height 1.6 mm. 8. Orinella beaufortensis, new species, holotype, USNM 204120 from USGS 25368, apertural view, height 2.7 mm. 5. NUMBER 61 281 ^■1, /■' / & JstA-^ -'L.': ,( 282 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY PLATE 47 1,2. Ringicula semistriata d'Orbigny, USNM 204126 from USGS 25369, height 2.0 mm: 1, apertural view; 2, profile of aperture. 3. Acteocina candei (d'Orbigny), USNM 204127 from USGS 25367, apertural view, height 4.0 mm. 4. Chrysallida beaufortensis, new species, USNM 204121 from USGS 25369, apertural view, height 2.9 mm. 5. Turbonilla abrupta Bush, USNM 204123 from USGS 25367, apertural view, height 4.9 mm. 6. Pyrgiscus daedaleum (Lea), USNM 204124 from USGS 25366, apertural view, height 3.4 mm. 7. Pyrgiscus sp., USNM 204125 from USGS 25368, apertural view, height 3.8 mm. 8. Chrysallida auroraensis, new species, holotype, USNM 204122 from USGS 25361, apertural view, height 3.5 mm. 4. NUMBER 61 283 REQUIREMENTS FOR SMITHSONIAN SERIES PUBLICATION Manuscripts intended for series publication receive substantive revievy (conducted by their originating Smithsonian museums or offices) and are submitted to the Smithsonian Institution Press with Form SI-36, which must show the approval of the appropriate authority designated by the sponsonng organizational unit. 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