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UNITED STATES DEPARTMENT OF T&E INTERIOR

MOLLUSCA FROM THE MIOCENE AND

LOWER PLIOCENE OF VIRGINIA

AND NORTH CAROLINA

i

PART 1. PELECYPODA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 199-A

UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Professional Paper 199-A

MOLLUSCA FROM THE

MIOCENE AND LOWER PLIOCENE OF

VIRGINIA AND NORTH CAROLINA

PART 1. PELECYPODA

BY

JULIA GARDNER

WITH A SUMMARY OF THE STRATIGRAPHY 

By W. G. MANSFIELD

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1943

For sale by the Superintendent of Documents, Washington, D. C. ------- Price 55 cents

CONTENTS

Abstract-._ ______-___________i______---_-__-_-_-___

Introduction _______________________________________

Stratigraphy of the Miocene of Virginia and the Miocene

and Pliocene of North Carolina, by W. C. Mansfield __

Summary- _____________________________________

Maryland________________________________

Miocene (Chesapeake group)_____________

Pliocene _______________________________

Virginia.__________________________________

Miocene (Chesapeake group)_____________

Pliocene-______________________________

North Carolina-____________________________

Miocene _______________________________

Pliocene._ __-___----_____-___-_______-_

Other States of the Atlantic coast-____________

Miocene strata of Virginia.______________________

Nomenclature. _____________________________

Calvert- formation _ _________________________

Choptank formation ________________________

St. Marys formation._______________________

Stratum A_____________________________

Zone 1, or Bulliopsis quadrata zone________

Zone 2, or Crassatellites meridionalis zone_ _ 

Stratigraphic sections.__________________

Yorkto wn formation ________________________

Zone 1, or Pecten clintonius zone__________

Zone 2, or Turritella alticostata zone. ______

Bed at Biggs farm._____________________

Sections in the Yorktown formation_______

Miocene strata of North Carolina...______________

Yorktown formation._______________________

Groups A and B________________________

Group C_______________________________

Group D______________________________

Group E_____________________________

Group F, bed at Mount Gould Landing. _ _ 

Duplin marL_______________________________

Pliocene strata of North Carolina.__-______---____

Geologic ranges of certain species _________________

Localities in Virginia and North Carolina..________

Systematic descriptions, by Julia Gardner-____-_-____

Order Prionodesmacea_________________________

Superfamily Nuculacea______________________

Family Nuculidae_______________________

Family Nuculanidae_ ___________________

Superfamily Arcacea________________________

Family Arcidae.________________________

Family Glycymeridae___________________

Superfamily Mytilacea______________________

Family Mytilidae_______________________

Superfamily Pectinacea______________________

Family Pectinidae______________________

Family Spondylidae-_-___-____________--

Superfamily Anomiacea____________ ________

Family Anomiidae______________________

Pag« 

1 

1

Page.

Systematic descriptions, by Julia Gardner—Continued. 

Order Prionodesmacea—Continued.

Superfamily Ostracea__________-___-_-_-_-___ 41

Family Ostreidae_______________________ 41

Order Anomalodesmacea_______________-_-___-___ 41

Superfamily Anatinacea____..___________-____ 42

Family Periplomatidae__________________ 42

Family Thraciidae______________________ 42

Family Pandoridae____________________ 44

Superfamily Poromyacea.___________________ 50

Family Verticordiidae___________________ 50

Order Teleodesmacea__________________________ 51

Superfamily Astartacea______________________ 51

Family Astartidae_____-______-_---_____ 51

Family Crassatellitidae__________________ 61

Superfamily Cyrenacea.^____________________ 64

Family Cyrenidae--_-_-_------__--_-_-__ 64

Superfamily Cyprinacea_____________________ 65

Family Euloxidae_______________________ 65

Family Pleurophoridae._________________ 66

Superfamily Isocardiacea____________________ 67

Family Isocardiidae_____________________ 67

Superfamily Carditacea______________________ 68

Family Carditidae______________________ 68

Family Condylocardiidae________________ 73

Superfamily Lucinacea______________________ 74

Family Lucinidae_-_-___________________ 74

Family Diplodontidae___________________ 79

Superfamily Leptonacea_____________________ 81

Family Leptonidae_____-_-______________ 81

Family Sportellidae_____________________ 83

Family Montaoutidae___________________ 85

Superfamily Chamacea_______-_---___-_-_-__ S§>

Family Chamidae_______._-__-_-______ 88

Superfamily Cardiacea___________-__________ 89

Family Cardiidae_______________________ 89

Superfamily Tellinacea.______-----________-_ 94

Family Tellinidae_____________________ 94

Family Semelidae_______________________ 100

Family Donacidae______________________ 105

Family Gariidae_-___-___-----__-_-_____ 107

Superfamily Solenacea_______________________ 108

Family Solenidae_______________________ 108

Superfamily Mactracea_______-______________ 109

Family Mactridae______________________ 109

Family Mesodesmatidae_________________ 115

Superfamily Veneracea______________________ 116

Family Petricolidae.____________________ 116

Family Cooperellidae______________-_____ 119

Family Veneridae_______________________ 120

Superfamily Myacea________________________ 138

Family Myacidae_______________________ 138

Family Corbulidae______________________ 139

Superfamily Adesmacea_____________________ 141

Family Pholadidae______________-_______ 141

Family Teredinidae_____________________ 143

Index. _________________________________________ 169

in
IV CONTENTS

ILLUSTRATIONS

Page 

PLATES 1-23. Miocene and Pliocene pelecypoda of Virginia and North Carolina._-____-__________-______--_---_-__--_- 145

FIGURE 1. Columnar sections of Horsehead, Stratford, and Nomini Cliffs, Va____________j______________--__-__--__-.._ 5

2. Section on shore of the James River, east of old Kings Mill Wharf, Va___-.___-________-__________-___-___-__ 9

3. Diagrammatic representation of the beds of zone 2 of the Yorktown formation within 2 miles southeast of Yorktown, Va____-____________________________________-____i_____---___-_-_--_---___--_-_-_-_--------_ 10

4. Index map showing Miocene and lower Pliocene localities in Virginia and North Carolina...___________________ 18

TABLES

TABLE 1. Correlation of the Atlantic and Gulf Coastal Plain deposits ranging in age from the upper part of the middle Miocene

to the Pleistocene_____________________•__________________________________-________________-_-_------ 3

2. Geologic range of species._____________________________________________________________________-t --____ 14
MOLLUSCA FROM THE MIOCENE AND LOWER PLIOCENE 

OF VIRGINIA AND NORTH CAROLINA

PART 1. PELECYPODA

By JULIA GARDNER

ABSTRACT

A brief sketch of the stratigraphy of the Miocene of Virginia 

and the Miocene and Pliocene of North Carolina was prepared 

by Dr. W. C. Mansfield before his death in July 1939. His 

purpose was "to provide a background of formational nomenclature" for the taxonomic treatment of the molluscan faunas. 

The physical nature and distribution of the upper Tertiary 

formations within those States are discussed, characteristic 

sections given, and diagnostic molluscan species listed.

Part 1 of the systematic report covers the Pelecypoda. A 

monographic treatment is not attempted, but 132 previously 

known species are considered, and 62 new species and subspecies 

are described and figured.

INTRODUCTION

Some 20 years ago I studied collections made in the 

course of investigations upon the later Tertiary formations by the State Surveys of Virginia and North Carolina. The taxonomic work was completed, and illustrations were made for all the new and most of the 

previously described species. This first report was not 

published.

The present report covers the same general field. It 

includes descriptions and illustrations of the new 

species, of several previously described species that 

were figured in publications not widely distributed or 

easily accessible, and of forms for which some biologic 

or stratigraphic information has been added. The 

report makes no claim to consistency of treatment or 

to completeness.

The greater number of the collections on which my 

early work was based were assembled before the details of the stratigraphy and the interrelationship to 

the faunas were understood. The late Dr. W. C. Mansfield, who was responsible for practically all the refinements of the stratigraphic sections that have been made 

during recent years and for the careful correlation of 

the faunas contained in these sections, was good enough 

to check the distribution of the species represented in 

my old collections and thus to give to them any stratigraphic significance that they may possess.1 The ac1 The important "Stratigraphic study of the mollusks of the Calvert 

and Choptank formations of southern Maryland," by Lois Schoonover, in 

Bull. Am. Paleontology, vol. 25, No. 94 B, pp. 1-135, 1941, unfortunately 

was received too late for Miss Schoonover's results to be given adequate 

consideration in this paper. Her zonal studies, particularly of the 

Pectan and Astarte groups, are essential alike to the stratigrapher and 

the paleontologist concerned with the molluscan faunas of the Middle 

Atlantic seaboard.

companying chapter on the stratigraphy, by Dr. 

Mansfield, is based upon work done by him alone.

I am greatly indebted both to Miss Frances Wieser, 

who has so skillfully retouched the photographs, and 

to Miss N. L. Bowen, who has sustained the drudgery of 

reworking an old manuscript with a cheerful patience 

and an ever alert mind and eye.

STRATIGRAPHY OF THE MIOCENE OF VIRGINIA AND THE MIOCENE AND PLIOCENE 

OF NORTH CAROLINA

By W. C. MANSFIELD

This summary of the stratigraphy of the Miocene of 

Virginia and the Miocene and Pliocene of North Carolina is intended to provide a background of formational nomenclature for Dr. Julia Gardner's systematic 

descriptions of Miocene and Pliocene Mollusca from 

those States. Though the literature pertaining to the 

region is extensive, a bibliography has been omitted. 

However, this omission is not a serious lack, for a bibliography of publications on the Miocene and Pliocene 

of Virginia to 1912 was compiled by Clark and Miller 2 

and a similar bibliography for North Carolina by 

Miller and Stephenson.3 Most of the important later 

publications have been noted in several papers by me.4

This chapter is based in part on information that has 

been published from time to time during recent years 

and on unpublished field and laboratory observations 

made by the writer.

SUMMARY 

MARYLAND

Miocene (Chesapeake group).—TfreMiocene deposits 

of Maryland (the Chesapeake group) were admirably

2 Clark, W. B., and Miller, B. L., Physiography and geology of the 

Coastal Plain province of Virginia: Virginia Geol. Survey Bull. 4, pp. 

19-45, 1912.

3 Clark, W. B., Miller, B. L., and Stephenson, L. W., The physiography 

and geology of the Coastal Plain of North Carolina: North Carolina 

Geol. and Econ. Survey, vol. 3, pp. 44-73, 1912.

4 Mansfield, W. C., New fossil mollusks from the Miocene of Virginia 

and North Carolina, with a brief outline of the divisions of the Chesapeake group: U. S. Nat. Mus. Proc., vol. 74, art. 14, pp. 1-11, 1929; 

The Chesapeake Miocene basin of sedimentation as expressed in the new 

geologic map of Virginia: Washington Acad. Sci. Jour., vol. 19, p. 266, 

fig. 2, 1929; Stratigraphic significance of Miocene, Pliocene, and Pleistocene Pectinidae in the southwestern United States: Jour. Paleontology, vol. 10, No. 3 1936; Additional notes on the molluscan fauna of 

the Pliocene Croatan sand of North Carolina: Idem, No. 7, pp. 665-668, 

1936.

1
MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

described in 1904 by Clark, Shattuck, and Ball,5 and 

this brief characterization is based largely upon their 

report.

The deposits of the Chesapeake group lie wholly 

within the tidewater region, on the Eastern Shore, 

between Chesapeake Bay and the Delaware River, in 

a broad belt between the Chester River on the north and 

Fishing Bay on the south; on the Western Shore, 

between Chesapeake Bay and the Potomac River, exten'ding inland as far as the District of Columbia. 

On both sides of Chesapeake Bay the strike of the 

beds is northeast.

In Maryland the Chesapeake group has been separated into three formations, all of middle Miocene age— 

in ascending order, the Calvert formation, the Choptank formation, and the St. Marys formation. The 

Yorktown, the uppermost formation of the Chesapeake group in Virginia, has not been recognized in 

Maryland.

The Calvert formation, 200 feet thick, is divided by 

Shattuck 5a into the Fairhaven diatomaceous • earth 

member, which is subdivided into three zones (zones 

1-3); and the Plum Point marl member, which is subdivided into twelve zones (zones 4-15). The Fairhaven member is especially characterized by diatomite. 

The Plum Point member consists of a series of sandy 

clays and clayey sands ranging in color from bluishgreen to buff and containing a large assemblage of 

vertebrate and invertebrate remains.

The Choptank formation, 80 feet thick, consists1 of 

reddish, yellowish, or greenish sand and sandy clay. 

Locally the materials are consolidated into hard rock. 

The formation is divided by Shattuck 6 into five zones 

(zones 16-20). Zones 17 and 19 contain well-preserved 

fossils in great abundance.

The St. Marys formation, 74 feet thick, consists of 

clay, sand, and clayey sand. The clay is usually of a 

dark color. The formation is divided by Shattuck ' 

into four zones (zones 21-24). The basal zone (zone 21) 

consists mainly of drab clay and appears to be devoid 

of fossils. The three other zones are fossiliferous, some 

parts being almost entirely composed of shells.

Pliocene.—No certain Pliocene deposits have been 

recognized in Maryland.

VIRGINIA

Miocene (Chesapeake group).—The Chesapeake 

group of Virginia, 575 feet thick, is divided into four 

formations, in ascending order, the Calvert, Choptank, 

St. Marys, and Yorktown.

5 Clark, W. B., Shattuck, G. B., and Ball, W. H., The Miocene deposits 

of Maryland: Maryland Geol. Survey, Miocene, pp. xxi-clv, pis. 1-9, 

1904.

5a Shattuck, G. B., Maryland Geol. Survey, Miocene, pp. Ixxii-lxxvii, 

1904.

6 Idem, pp. Ixxxi-lxxxii. 

T Idem, p. Ixxxv.

The Calvert formation, 200 feet thick, consists of 

dark-gray or olive sandy clay, usually diatomaceous.

The Choptank formation, 50 feet or more thick, consists of dark-brown, rather soft sand and greenish-gray 

clayey sand alternating with indurated sandstone 

layers. It is not recognized widely.

The St. Marys formation } 180 feet thick, contains 

a lower part, "stratum A," that consists of nearly un~ 

fossiliferous dark sandy plastic clay; and an overlying fossiliferous part, of bluish clay and light-colored 

sand, that is divided into two faunal zones.

The Yorktown formation, 145 feet thick, consists 

dominantly of gray to buff sands. It is divided into 

two faunal zones, and the upper zone is subdivided into 

three minor parts.

The divisions of the Chesapeake group, as recognized 

by me,8 are as follows:

Upper Miocene:

Yorktown formation:

Zone 2, or Turritella alticostata zone: 

Upper part (beds at Suffolk). 

Middle part (beds at Yorktown). 

Lower part (including C7i«ma-bearing bed). 

Zone 1, or Pecten clintonious zone. 

Middle Miocene:

St. Marys formation:

Zone 2, or Crassatellites meridionalis zone. 

Zone 1, or Bulliopsis quadrata zone. 

Stratum A (unfossiliferous dark clay). 

Choptank formation. 

Calvert formation.

Pliocene.—No certain Pliocene deposits have been 

recognized in Virginia.

NORTH CAROLINA

Miocene.—The lower formations of the Chesapeake 

group are not exposed in North Carolina. The uppermost part of the St. Marys formation may be present 

in the lowest part of some exposures, but the entire 

Yorktown formation is represented, though not all exposures may be accurately placed in the formation. 

The Yorktown (late Miocene) in the northern part of 

North Carolina contains a fauna suggestive of deposition in colder water than that forming the environment 

of the fauna of the Miocene beds in the southern part 

of the State.9 The deposits in the southern part of the 

State, the Duplin marl, represent the uppermost Miocene and are equivalent to the uppermost Yorktown, 

though constituting a warm-water facies. At no place 

are the Miocene deposits, as now exposed, more than 

50 feet thick.

Pliocene.—The Croatan sand, in the northeastern

8 Mansfield, W. C., New fossil mollusks from the Miocene of Virginia 

and North Carolina, with a brief outline of the divisions of the Chesapeake group : U. S. Nat. Mus. Proc., vol. 74, art. 14, pp. 1-2, 1929.

9 Mansfield, W. C., The Chesapeake Miocene basin of sedimentation as 

expressed in the new geologic map of Virginia: Washington Acad. Sci. 

Jour., vol. 19, p. 266, fig. 2, 1929.
PART 1. PELECYPODA

part of the State,10 and the Waccamaw formation, in 

the southern part,11 represent the Pliocene epoch. 

Both are thin superficial deposits.

OTHER STATES ON THE ATLANTIC COAST

In listing the distribution of species in the systematic part of this work, various other formations of 

Tertiary and Quaternary age in States north of Maryland and in South Carolina, Georgia, and Florida are 

cited. Most of these formations are shown in table 1, 

and also the commonly accepted correlations with 

European divisions of the later Tertiary.

MIOCENE STRATA OF VIRGINIA 

NOMENCLATURE

As indicated in the summary on page 2, all the 

formations of the Chesapeake group are present in 

Virginia. The existence of these deposits was recognized in early geologic work in the region, and though 

for long only a very simple nomenclature was applied 

to them, the terminology now in use eventually appeared. As it may be of interest to record in compact 

form the usage of the various authors who have dealt 

with the Miocene strata, the appended list is presented.

The list gives the name of the author, the year of 

his publication, and the name or names used by him for 

the Miocene deposits or a brief statement of his results. 

The name cited may include more deposits than are 

now referred to the Miocene epoch. If the item cited 

refers to a State other than Virginia, this is indicated.

1809. Maclure, William:

Alluvial (in part). 

1820. Hayden, H. H.:

Alluvial (in part). 

1822. Cleveland, Parker:

Alluvial (in part).

1824. Finch, John:

Tertiary (in part).

1825. Van Renssellaer, Jeremiah:

Tertiary, Virginia (in part).

Upper Marine and London clay (?), Maryland.

1828. Vanuxem, Lardner, and Morton, S. G.: 

Tertiary (in part).

1829. Morton, S. G.:

Upper Marine in Maryland and probably southward.

1830. Conrad, T. A.:

Upper Marine in Maryland.

1832. Conrad, T. A.:

Upper Marine or upper Tertiary.

1833. Lea, Isaac:

Older Pliocene.

1834. Conrad, T. A.: 

Pliocene.

10 Mansfield, W. C., Notes on Pleistocene faunas from Maryland and 

Virginia and Pliocene and Pleistocene faunaus from North Carolina: 

U. S. Geol. Survey Prof. Paper 150, pp. 129-133, 1928; Additional notes 

on the molluscan fauna of the Pliocene Croatan sand of North Carolina : 

Jour. Paleontology, vol. 10, no. 7, pp. 665-668, 1936.

11 Miller, B. L., Tertiary formations : North Carolina Geol. and Econ. 

Survey, vol. 3, pp. 256-258, 1912.

1835. Conrad, T. A.:

Older Pliocene (in part). 

1835. Conrad, T. A.:

Medial Pliocene (in part).

1835. Rogers, W. B.:

Middle Tertiary=Miocene of Lyell.

1836. Rogers, W. B.:

Miocene. 

1836 or 1837. Conrad, T. A.:

Medial Tertiary or older Pliocene.

1837. Rogers, W. B.: 

Miocene.

1838. Conrad, T. A.:

Medial Tertiary or older Pliocene.

1838. Rogers, W. B.: 

Miocene.

1839. Rogers, H. D., and W. B.: 

Meiocene (Miocene).

1840. Conrad, T. A.:

Medial Tertiary.

1840. Rogers, W. B.:

Miocene—Horizontal beds (?). 

Yellow marl. 

Blue marl.

1841. Rogers, W. B.:

Meiocene (Miocene).

1842. Conrad, T. A.:

Medial Tertiary or Miocene.

1842. Lyell, Charles:

Miocene [less] excluded infusorial beds.

1843. Tuomey, Michael:

Miocene (includes infusorial beds). 

1843. Conrad, T. A.:

Miocene.

1843. Rogers, W. B.:

Miocene (includes infusorial beds).

1844. Rogers, H. D.:

Miocene (includes infusorial beds).

1845. Conrad, T. A.:

Medial Tertiary or Miocene. 

1845. Lonsdale, William:

Miocene.

1845. Lyell, C.:

Miocene=Crag of England and faluns of Loire.

1846. Lea, H. C.:

Miocene. 

1850. Wyrnan, J.:

Miocene (includes infusorial beds). 

1853. Hitchcock, B.:

Miocene (includes infusorial beds). 

1853. Marcou, Jules:

Miocene. 

1861. Conrad, T. A.:

Medial Tertiary or Miocene.

1861. Rogers, W. B.:

Meiocene (Miocene) (infusorial beds).

1862. Conrad, T. A.:

Miocene or Upper Tertiary.

1863. Dana, J. D.:

Yorktown or Miocene.

1864. Meek, F. B:

Miocene. 

1866,1868, 1869. Conrad, T. A.:

Miocene. 

1877. Stodder, C.:

Miocene (for Richmond, infusorial deposit). 

1880. Dana, J. D.:

Miocene, Yorktown period (in part).
MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1882. Heilprin, A.: 

Miocene:

Marylandian (uncertain for lower bed). 

Virginian. 

1884. Heilprin, A.: 

Miocene:

Virginian.

Oarolinian (not unlikely). 

1888. Heilprin, A.:

Metagene (used instead of Miocene).

1891. Barton, N. H.:

Miocene, Chesapeake group. (Separates it into three 

beds.)

1892. Ball, W. H., and Harris, G. D.: 

Miocene, Chesapeake group.

1893. Harris, G. D.: 

In Maryland:

St. Marys fauna. 

Jones Wharf fauna. 

Plum Point fauna. 

1893. Dall, W. H., and Harris, G. D.:

In Maryland: St. Marys, Jones Wharf, and Plum Point.

Virginia: Yorktown considered younger. 

1895. Dana, J. D.:

Miocene period (Yorktown epoch). 

L896. Darton, N. H.:

Miocene, Chesapeake group. 

1898. Dall, W. H.:

Miocene, Chesapeake group=Helvetian of Europe. 

1902. Shattuck, G. B.: 

For Maryland:

St. Marys formation. 

Choptank formation. 

Calvert formation. 

1904. Clark, W. B., and others: 

For Maryland:

Chesapeake group: 

St. Marys, 4 zones. 

Choptank, 5 zones. 

Calvert, 15 zones. 

1904. Dall, W. H.:

For Atlantic and Gulf: 

Duplin (North Carolina). 

Suffolk (Virginia). 

Yorktown (Virginia). 

Alum Bluff (Florida). 

St. Marys (Maryland). 

Choptank (Maryland). 

James River (Virginia). 

Calvert (Maryland). 

Petersburg (Virginia). 

1909. Berry, E. W.:

Places Richmond diatomaceous deposits in Calvert

formation.

1910 (read in 1908). Miller, B. L.: 

Yorktown. 

St. Marys. 

Calvert.

1910 (Read in 1908). Miller, B. L.: 

Yorktown. 

St. Marys. 

Choptank. 

Calvert.

1911. Watson, T. L.: 

Yorktown. 

St. Marys. 

Calvert.

1911. Berry, E. W.:

Richmond; fossil plants assigned to Calvert=middle 

Miocene.

1912. Clark, W. B., and Miller, B. L.: 

Chesapeake group: 

Yorktown. 

St. Marys. 

Calvert.

1913. Sanford, S.:

Chesapeake group: 

Yorktown. 

St. Marys. 

Choptank (?) 

Calvert.

1914. Olsson, A.:

Suggests placing Petersburg fauna with St. Marys or

younger. 

1916. Watson T. L.:

Yorktown.

St. Marys.

Calvert.

1916. Berry, E. W.:

Places Calvert in middle Miocene or equivalent to 

Tortonian.

1917. Olsson, Axel: 

Miocene: 

Upper:

Yorktown stage.

Murfreesboro stage. 

Middle:

St. Marys stage. 

Lower:

Choptank stage.

Calvert stage.

1921. Cooke, C. Wythe:

Duplin and Yorktown (North Carolina, Virginia) =

upper Miocene. 

Calvert, Choptank, and St. Marys=middle Miocene.

1922. Olsson, Axel: 

Miocene: 

Upper:

Yorktown stage. 

Murfreesboro stage. 

Middle:

St. Marys stage. 

Choptank stage. 

Calvert stage.

1929, 1936. Mansfield, W. C.: 

Miocene: 

Upper:

Yorktown formation:

zone 2 (Turritella alticostata). 

zone 1 (Pecten clintonius). 

Middle:

St. Marys formation:

zone 2 (Crassatellites meridionalis) . 

zone 1 (Bulliopsis quadrata). 

stratum A. 

Choptank formation. 

Calvert formation.

CALVERT FORMATION

Lithologic character and thickness.—The material 

composing the Calvert formation consists largely of 

dark-gray or olive sandy, usually diatomaceous clay, 

which changes to a lighter color when weathered. It is
TABLE 1.—Correlation of the Atlantic and Gulf Coastal Plain deposits ranging in age from the upper part of the middle Miocene to the Pleistocene

i QJ .S3 a 

-Sg ^3

Pliocene.

Miocene.

Upper.

Middle.

Lower.

Upper.

Middle.

European equivalent

Sicilian (Arnian).

Astian.

Plaisancian.

Sahelian. Pontian.

Sarmatian.

Tortonian or upper 

Vindobonian.

Helvetian.

New Jersey

Kirkwood 

formation.

Maryland

Deposits at Wailes 

Bluff. 1

(?)

St. Marys formation.

Choptank formation.

Calvert formation.

Virginia

)rktown formation.

x z<

Beds at Suffolk, 

with bed at 

Biggs Farm at 

** top.

0>

a ® Beds at Yorktown.

C/iama-bearing 

bed.

me 1.

St. Marys formation.

Zone 2.

Zone 1.

Choptank formation.

Calvert formation.

North Carolina

(?)

(?)

Croatan sand to north.

Uppermost Yorktown, 

with bed at Mt. Gould 

at top.

Waccamaw formation to south.

Duplin marl.

Equivalent to the beds at Yorktown, Va.

C/zawa-bearing bed.

Zone 1.

?St. Marys formation. 5

(?)

South Carolina

Deposits on Yonges Island. 1

(?)

(?)

Waccamaw formation.3

Duplin marl.

Raysor marl.

Oeorgia

Duplin marl at 

Porters Landing.

Florida

Marl on North Creek. 1

Deposits on Myakka River.2

(?)

Limestones of Tamiami Trail.4 

Caloosahatchee marl.

Choctawhatchee formation.

Cancellaria zone (upper part) .

Cancellaria zone (lower part).

"Aluminous clay."

Ecphora zone.

Area zone (upper part).

Area zone (lower part). 

Yoldia zone.

Shoal River formation.

Oak Grove sand. 6

»The fossiliferous beds in the Pleistocene not necessarily correlated.

2The fauna included by Ball in the Myakka River fauna may include some Pleistocene.

3 Beds at Grove Plantation tentatively put in the Waccamaw formation by Cooke; may be older.

4 Position relative to Caloosahatchee marl not precisely known.

5 Mainly concealed except at low-water stage.

6 Exact correlation with the Calvert formation not folly established.

401033—42 (Face p. 4)

PART 1. PELECYPODA

believed to attain a maximum thickness of 200 feet. 

The formation is exposed in the Horsehead, Stratford, 

and Nomini Cliffs (see p. 5) and forms the lower 

40 feet of the section at Carter Wharf, on the Rappahannock River. Diatomaceous deposits at Richmond 

and Petersburg have usually been referred to the 

Calvert.

Stratigraphic relations.—The Calvert formation 

rests unconformably upon either the Eocene or older 

deposits and is overlain, apparently unconformably, 

either by the Choptank formation or by a later deposit.

Paleontologic character.—The molluscan fauna is 

sparse and poorly preserved. The following species 

were collected by me and appear to be the more 

abundant forms: Ecphora tricostata Martin, PedaHton 

maxillatum (Deshayes), and Pecten madisonius Say. 

Certain deposits have yielded vertebrate remains and 

fossil plants. A separation of the deposits into faunal

Nomini Cliffs,

lected by me: Area staminea Say, Pecten marylandicus 

Wagner, Astarte obruta Conrad. It is believed that 

Shattuck's zones 16 to 20 of the Maryland sequence 13 

may be recognized in Virginia.

The Horsehead, Stratford, and Nomini Cliffs 14 form 

a series of northward-facing bluffs about 6 miles long, 

extending from a point a mile east of the mouth of 

Popes Creek eastward nearly to Currioman Bay. These 

cliffs afford exposures of the upper part of the Calvert 

formation, all of the Choptank formation, and the 

lower part of the St. Marys formation. In general the 

formations are less fossiliferous here than in the Calvert 

Cliffs, on Chesapeake Bay in Calvert County, Md., 

though at one place in the lower part of the Nomini 

Cliffs fossils are abundant in the Choptank formation. 

The stratigraphic and structural relationships of the 

formations exposed in the cliffs are shown in figure 1.

The Calvert formation in these sections consists

Late Miocene or 

Pliocene and Pleistocene Em Undifferentiated

St Marys formation

Zone 2 I

Choptank formation Cafvert formation

Zone 2O Zone 19 Probably 

zonesI6to16

FIGURE 1.—Columnar sections of Horsehead, Stratford, and Nomini Cliffs, Va.

zones corresponding to those recognized by Shattuck 12 

in the Calvert of Maryland is impracticable because of 

the lack of faunal data.

CHOPTANK FORMATION

Lithologio character and thickness.—The material 

composing the Choptank formation consists of darkbrown, rather soft fossiliferous sand alteranting with 

indurated sandstone layers. Its thickness is not definitely determined in Virginia but may exceed 50 feet.

Distribution.—The areal distribution of the Choptank in Virginia is not precisely known. It is believed, 

however, that this formation underlies the St. Marys 

formation in part of the area between the Potomac and 

Rappahannock Rivers. It appears that this formation 

thins southward and finally disappears, and where it is 

absent the younger St. Marys formation rests upon the 

Calvert instead of the Choptank. At only two localities 

were fossil remains found that established the presence 

of this formation in VirginiX—one in the Nomini Cliffs, 

about 1% miles west of the east end of the cliffs, and 

the other near Carter Wharf, on the Rappahannock 

River. The section in the Nomini Cliffs is described 

below.

Paleontologic characters.—The molluscan fauna is 

poorly preserved. The following characteristic species, in addition to others of longer range, were col12 Shattuck, G. B., Maryland Geol. Survey, Miocene, pp. Ixxii-lxxvii, 

1904.

mainly of a rather compact greenish-gray diatomaceous sandy clay and contains a few poorly preserved 

invertebrate fossils. The upper limit of the formation 

has been drawn at^a plane about 5 feet above a thin 

bed containing many Isocardia, which may represent 

the Isocardia bed referred to zone 14 of Shattuck in 

the Calvert formation of Maryland.

The lowest bed of the Choptank formation, believed 

to represent Shattuck's zones 16 to 18, consists of 

greenish-gray clayey sand and at a locality 1% miles 

west of the east end of the Nomini Cliffs contains two 

zones of fossils, one within 3 feet above the beach 

and the other 10 to 12 feet higher. In the lower layer 

are Grassatellites turgidulus (Conrad), Phacoides 

crenulatus (Conrad), Diplodonta subvexa (Conrad)?, 

a large variety of Isocardia fraterna (Say), Cardium 

sp., and Venus plena (Conrad) ?. In Maryland Grassatellites turgidulus occurs only in zone 17 of the Choptank formation.

The middle part of the Choptank formation, assigned 

to zone 19, consists of dark-brown soft fossiliferous 

sand, with a sandstone layer about 2 feet thick at the 

top containing many individuals of Pecten madisonius 

Say. In this sand are also Area staminea Say, Pecten 

marylandicus Wagner, Astarte ol>ruta Conrad, Crassa18 Shattuck, G. B., Maryland Geol. Survey, Miocene, pp. Ixxxi-lxxxii, 

1904.

M Stephenson, L. W., Cooke, C. W., and Mansfield, W. C., 16th Internat. Geol. Cong. Guidebook 5, pp. 25-28, 1932.
6 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

tellites marylandicus (Conrad), Thracia sp., Dosinia 

sp., and Corbula idonea. Conrad. In the Choptank 

formation of Maryland Crassatellites marylandicus has 

been found only in zone 19.

The upper part of the Choptank formation consists 

of sandy clay that contains a few vertebrate fossils 

but no invertebrates. It is believed to correspond to 

zone 20.

The next higher bed, which represents the lower part 

of the St. Marys formation and is assigned to zone 21, 

consists of very plastic clay. At the west end of the 

Stratford Cliffs this clay, though only a few feet thick, 

contains Turritella plebela Say, Turritella variabilis 

Conrad, Glycymeris subovata (Say) var., Area sp. 

(young individual), Ostrea disparilis Conrad, Astarte 

aff. A. obruta Conrad, Euloxa Idtisulcata (Conrad), 

Chione cf. C. athleta Conrad, Spisula confraga (Conrad), and Corbula sp.

ST. MARYS FORMATION

The St. Marys formation in Virginia may profitably 

be subdivided. The lower, nearly unfossiliferous part 

is designated "stratum A." The overlying fossiliferous 

part is subdivided into two faunal zones—zone 1, or 

Bulliopsis quadrat® zone, below, and zone 2, or Crassatellites meridional-is zone, above. It attains a thickness 

of 180 feet.

Stratum A.—Stratum A consists of dark-gray sandy 

clay, soft when wet and stiff when dry. It is the 

highest bed in the Miocene sequence in the Nomini 

Cliffs. Near Ethel and Garlands Mill, between the 

Potomac and Rappahannock Eivers, it is the lowest bed 

exposed. It is believed to represent Shattuck's zone 21 

and perhaps zone 22. 15

Zone 1, or Bulliopsis quadrata zone.—Zone 1 consists predominantly of blue to greenish sandy clay. 

It crops out at an altitude of 75 to 80 feet at Garlands 

Mill and near Warsaw, Richmond County; below 

Bowlers Wharf, on the Rappahannock River, and at 

Essex Mill, about 5 miles south of Tappahannock, 

Essex County. It is believed to correspond to zones 23 

and 24 of Shattuck, and it carries a well-preserved 

and characteristic molluscan fauna. Conspicuous 

species are Terebra simplex Conrad, Conus diluvianus 

Green, Bulliopsis quadrata Conrad, Turritella plebeia 

Say, Glycymeris tumulus (Conrad), Area idonea Say, 

and Pecten santamaria Tucker.

Zone 2, or Crassatellites meridionalis zone.—Zone 2 

consists of bluish sandy clay overlain by loose lightcolored beachlike sands. It crops out along the Rappahannock Hiver from Jones Point southward to a point 

just below Burhans Wharf; along the James River 

from Cobham Bay, where it dips below water level, 

to a point a little above Claremont Wharf. South of

16 Shattuck, G. B., Maryland Geol. Survey, Miocene, p. Ixsxv, 1904.

the James River no surface outcrops or exposures 

were found in the stream channels. It is apparently 

unconformable with the overlying Yorktown. This 

apparent unconformity is indicated not only by an 

abrupt faunal change but also by the fragmental nature 

of the upper part of the St. Marys formation.

The fauna of zone 2 is closely allied to that of zone 1, 

differing mainly in containing slightly more modern 

types. Prominent species are Turritella plebeia Say, 

Glycymeris tumulus (Conrad) (or1 a closely related 

form), Pedalion maxillatum (Deshayes), Pecten santamarla. middlesewensis Mansfield, P. eboreus urbanndensis Mansfield, Crassatellites meridionalis surryensis 

Mansfield, and C. undulatus url)annaensis Mansfield.

Stratigraphic sections.—The following sections show 

the relations of the strata at two localities on the James 

River and one locality near Lanexa, on the Chickahominy River.

Section of right bank of James River at Schmidts Bluff, 8^ miles 

below Claremont Wharf, Surry County, Va.

Feet

Pleistocene: Reddish gravelly clay and sand————__—— 20-25 

Unconformity.

Miocene:

Yorktown formation, probably zone 2:

Gray indurated fossiliferous marl bed resembling

one at Marlboro, Va___———___————— 4-5 

Unfossiliferous reddish sand_______——__—— 3-4

Yorktown formation, zone 1: Grayish to buff sand containing Turritella variabilis pilsbryi Gardner, Olycymeris subovata (Say), Pecten clintonius Say, Pecten jeffersonius Say, Pecten eboreus watsonensis 

Mansfield, Astarte eovaltata Conrad, Astarte undulata deltoidea Gardner, Astarte uttdulata vaginulata 

Dall, Crassatellites undulatus cyclopterus Dall, Phacoides (Pseudomiltha) anodonta Say, Venericardia 

granulata Say, Venus rileyi Conrad, Spisula confraga Conrad, and Kuphus calamus H. C. Lea. 

Pedalion maxillatum does not occur in this bed. - 

Contact with underlying bed is evident but not very 

irregular________________________<_ 8

St. Marys formation, zone 2: Material in the upper 

part similar to the overlying bed but containing a 

different fauna. The following species were collected here: Glycymeris cf. O. tumulus (Conrad), 

Area (Barbatia) centenaria Say, Area idonea Say, 

Pecten santamaria middleseseensis Mansfield, Pedalion maxillatum (Deshayes). Pedalion maxillatum 

and Pecten madisonius are abundant. The lower 

part contains more clay______________—— 25

Section of right banJc of James Kiver just above Sunken Marsh 

CreeJc, 2 miles below Claremont Wharf, Surry County, Va.

Pleistocene: Feet 

Yellowish to red sandy loam with gravel at the base__ 10-12 

Band of large pebbles and cobbles as much as 1 foot in

diameter__________________________ 1 

Cross-bedded reddish gravel with 1-foot band of clay 

at base_——_,__„__„______________ 6
PART 1. PELECYPODA

Section of right bank of James River just above Sunken Marsh 

Creek, 2 miles below Claremont Wharf, Surry County, Va.— 

Continued 

Unconformity. 

Miocene:

Torktown formation, zone 1: Feet

Brown to gray medium-grained sands with fossil

impressions______________________ 9

Highly fossiliferous fine gray to buff sands, with a 

few black grains intermixed, containing Turritella variabttis pilsbryi Gardner, Fissuridea redimicula Say, Pecten jeffersonius Saj% Crassatellites unditlatus Say, Isocarclia fraterna Say, 

Astarte undulata vaginulata Dall, Astarte undulata deltoidea Gardner, Astarte exaltata Conrad, 

and Dentalium attenuatum Say_________ 15

Covered________________________ 2 

St. Marys formation, zone 2:

Blue medium- to fine-grained clayey sand with 

Turritella plebeia carinata Gardner, Dentalium 

attenuatum Say, Area idonea Conrad, Pecten 

santamaria middlesexen sis Mansfield, Crassatellites meridionalis surryensis Mansfield, Astarte perplana Conrad, Pleiorytis centenaria 

Conrad_________________________ 8

Blue clayey sand with many fossils, especially 

Area, Peclen, and Pedalion____________ 10

Blue clayey sand with Turritella, Scapharca, and 

Pedalion maxillatum. The following species 

were collected 8 to 20 feet above water level: 

Turritella plebeia carinata Gardner, Fissuridea 

near F. nassula Conrad, Dentalium attenuatum 

Conrad, Glycymeris subovata (heavy form), 

Area idonea Conrad, Area virginiae Wagner, 

Pecten santamaria middle sexensis Mansfield, 

Crassatellites meridionalis surryensis Mansfield, 

Venericardia aranulata Say, Phacoides contractus Say, Dosinia acetabulum Conrad, Chione 

dalli Olsson, Corbula inaequalisi Say______ 10

Blue fine-grained clayey sand, slightly fos-

•siliferous_,__,___________________ 4

Blue fine-grained clayey sand containing Turritella 

plebeia carinata Gardner, Area idonea Conrad, Pecten santamaria middleseivensis Mansfield, Ostrea disparilis Conrad, Pleiorytis centenaria (Conrad)—________________ 4

(The series of blue clays forming zone 2 do not 

contain the black grains observed in other beds.)

Section in Chesapeake & Ohio Railitxty cut one-third of a mile 

below Lanexa, near left bank of the Chickahominy River, New 

Kent County, Va.

Pleistocene: Feet 

Reddish sandy clay, forming a nearly vertical cliff_ 8-10 

Thinly laminated pink to mottled clays separated by

narrower bands of sand________________ 8-10 

Laminated, slightly cross-bedded mottled clays, pink

predominating ______________________ 27-30 

Greenish-gray coarse sandy clay with a 2- to 3-inch

ferruginous band at the base______________ 3 

Clayey sand__________________________ 3%

Unconformity.

Miocene:

Yorktown formation, zone 1: Indurated shell bed in 

a matrix of gray to buff glauconitic sand containing many Pecten jeffersonius Say and Ostrea disparilis Conrad_____—________________ 3

Section in Chesapeake & Ohio Railway cut one-third of a mile 

below Lanexa, near left bank of the Chickahominy River, New 

Kent County, Va.—Continued

M iocene— Continued. 

Unconformity.

St. Marys formation, zone 2: Feet 

Loose unfossiliferous fine-grained buff sand—— 4 

Sand similar to above but containing Pecten 

eboreus urbannaensis Mansfield in great abundance, as well as Pedalion maxillatum (Deshayes) _______.______—__———————— 11 

Concealed to railroad tracks.———————————— 10-12

The base of the Pecten je-ffersonius bed is about 50 

feet above sea level.

YORKTOWN FORMATION

The Yorktown formation has been conveniently divided into two faunal zones—zone 1, or Pecten clintonius zone, below and zone 2, or Turritella alticostata 

zone, above. Zone 2 may in turn, be subdivided into 

three minor divisions, to which for reference have been 

applied the terms, in ascending order, "6Viam#.-bearing 

bed," "beds at Yorktown," and "beds at Suffolk." The 

Yorktown formation attains a thickness of 145 feet.

Zone 1, or Pecten clintonius zone.—Zone 1 consists 

largely of medium-grained gray to buff sands. It constitutes the earliest deposit referred to the Yorktown 

formation and apparently rests uncomformably on the 

St. Marys formation. Its upper limit is less distinctly 

marked, though the overlying deposits are usually 

glauconitic and in many places contain coarse sediments. 

Its contact with the St. Marys formation dips to the 

southeast at a rate of 3 to 5 feet to the mile. The thickness of this zone probably does not exceed 25 feet.

This zone is exposed at Bellefield, on the York Eiver, 

where for a short distance the bed rises 2 to 3 feet above 

the beach; and at several localities between the York 

and Eappahannock Eivers. Along the James River 

it is exposed at many places between old Kings Mill 

Wharf and a point 2 miles below City Point. (See 

fig. 2, bed v.) From Cobham Bay, on the right bank 

of the James Eiver, to Claremont Wharf, zone 1 rests 

on the St. Marys formation, rising to an altitude of 30 

to 35 feet at Claremont Wharf.

The fauna of this zone is characterized not only by 

the presence of certain peculiar species but also by 

the initiation of ^several species that are represented 

by many individuals in later' deposits. Some of the re- 

.stricted species are Fusinus propeparilis Mansfield, Gly~ 

cymeris subovata plagia Dall, Pecten clintonius Say, 

Astarte undulata vaginulata Dall, and Astarte undulata 

deltoidea Gardner. Some of the species that appear 

here first are Conus marylandicus Green, "Drillia" 

lunata (H. C. Lea), Pecten je-ffersonius Say, Phacoides 

cribrarius (Say), Divavicella quadrisulcata (D'Orbigny), and .Cardium virginiammi Conrad. Other 

fossils are listed on page 9. -;"
8 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Zone 1 includes in part the Murfreesboro stage of 

Olsson.16 The term "Murfreesboro" is preoccupied, 

having been used by Safford and Killebrew 17 to designate the lowest limestone of the Central Basin of Tennessee. As the fauna of this zone is more closely related to the fauna of the Yorktown formation than to 

that of the St. Marys formation, I have placed it in the 

Yorktown.

Zone 2, or Turritetta alticostata Bone.—Zone 2 is divisible into three minor parts.

The lowest part consists of coarse sand containing 

many specimens of Chama and other fossils; it is excellently exposed in a bluff on the north shore of the 

James Eiver east of the old Kings Mill Wharf. In a 

section of the bluff given by Stephenson, Cooke, and 

Mansfield 18 (see fig. 2), the 6^A«ma-bearing bed is indicated by "bed 10" and is underlain by zone 1 of the 

formation. Higher beds in the lower part of zone 2, 

exposed in the same bluff above the C^ama-bearing bed, 

are indicated by "beds a?, y, 0" and consist of gray to 

buff sands and laminated clay. Equivalent beds are 

present on the York Eiver southeast of Yorktown and 

are indicated 19 in figure 3 by "beds a, 5, <?, d" Fossils 

of the lowest part of zone 2 are listed on page 10.

The middle part of zone 2, the f ragmental beds, consists of sands and cross-bedded clays containing broken 

and entire shells and is typically exposed in the bluffs 

at Yorktown. This part is indicated in figure 3 by 

"beds e. /." Fossils of the middle part of zone 2 are 

listed on page 10.

The upper part of zone 2 overlies the f ragmental beds 

and is typically exposed at Suffolk, Va. These beds 

consist largely of gray to blue sands that oxidize to 

buff. The molluscan fauna is well preserved. The more 

abundant forms are Pecten eboreus eboreus Conrad, P. 

jeffersonius Say (having 8 or 9 ribs), P. jeffersonius 

edgecombensis Conrad, and Area improcera Conrad. 

Among the mactroids, Mulinia congesta Conrad is represented by a large, elongate form and Spisula delumbis 

Conrad by a light, thin form. On the York Eiver 

above Yorktown the beds exposed as far as Indian 

Creek appear to lie in a synclinal trough and to be 

higher in the series than the f ragmental beds (middle 

part of zone 2) exposed at Yorktown. At the first 

exposure above Yorktown a fragmental bed lies at the 

base of the section, but it soon disappears beneath the 

beach a short distance above. A blue clayey sand rests 

upon this bed, and its fauna is characterized by the 

presence of many small dark-colored oysters, Ostrea 

sculpturata. Similar sediments containing the darkM Olsson, Axel, The Murfreesboro stage of our east coast Miocene: 

Bull. Am. Paleontology, vol. 5, No. 28, pp. 153-164, 1917.

11 Safford, J. M., and Killebrew, J. B., The elements of the geology of 

Tennessee, p. 125, 1900.

M Stephenson, L. W., Cooke, C. W., and Mansfield, W. C., 16th Internat. Geol. Cong. Guidebook 5, p. 35, 1932.

»Idem. p. 32. v

colored oyster were noted near water level 1% miles 

below Indian Field Creek and in the bluffs on both sides 

of this stream. Upon the blue clayey sand rests a buff 

to gray fine-grained sand, which can be observed from 

half a mile to 1 mile above Yorktown. It is the Toldia 

bed of Harris. Fossils from the beds above Yorktown 

are listed on page 10.

Bed at Biggs farm.—Fossils collected by me in 1922 

on the Biggs farm, 3 miles west of Franklin, Southampton County, and about 21 miles nearly west of Suffolk, 

Va., are of special interest because they appear to be 

more closely related to those of the Duplin marl at the 

Natural Well, North Carolina, than any others so far 

collected from Virginia. This fauna may have lived 

near or at the end of the last Miocene marine invasion 

in Virginia and apparently at a time a little later than 

the fauna in the neighborhood of Suffolk, Va., but not 

much later. The cooler-water fauna at Suffolk is 

usually regarded as largely contemporaneous with the 

warmer-water fauna of the Duplin marl to the south. 

I place the exposure at the Biggs farm in the uppermost part of zone 2 of the Yorktown formation.

The bed at the Biggs farm lies 6 to 8 feet below the 

surface and is overlain by a coarse gray sand, probably 

of Pleistocene age. The material is a gray sand containing many entire and broken shells. The top of the 

bed is estimated to be 50 feet above sea level.

In 1929 20 I suggested the contemporaneity of the 

deposit at the Biggs farm and the Duplin marl, and in 

1930 21 1 noted the presence of Conus adversarms Conrad and Fasciolaria rhomboidea, Rogers at this locality.

The species collected from this locality are listed 

below. Those whose names are preceded by an asterisk 

especially show relationship to the fauna of the Duplin 

marl.

Aeteocina (fragment).

Terebra (fragment).

"Drillia" cf. D. myrmecoon Dall.

*Conus adversarius Conrad.

*Olivella nitidula (Dillwyn). 

Marginella bella Conrad var. 

Marginella limatula Conrad. 

Mitramorpha cf. M. mitrodita Gardner.

*Fasqiolaria rhomboidea Rogers. 

Fulgur canaliculatum eanaliferum Conrad. 

Ilyanassa cf. I. schizopyga Dall. 

Ilyanassa granifera Conrad. 

Nassa cf. N. johnsoni Dall. 

Urosalpinx trossulus Conrad. 

Seila adamsi (H. C. Lea).

* Turritella sp.

Petaloconchus sculpuratus (H. C. Lea) 1 

Crepidula fornicata cymbaeformis Conrad. 

Crepidula aculeata costata Morton.

20 Mansfield, W. C., The Chesapeake Miocene basin of sedimentation 

as expressed in the new geologic map of Virginia: Washington Acad. 

Sci. Jour., vol. 19, No. 13, p. 266, fig. 2, 1929.

21 Mansfield, W. C., Miocene gastropods and scaphopods of the Choctawhatchee formation of Florida: Florida Geol. Survey BulL 3, pp. 32, 

63, 1930.
PART 1. PELECYPODA 9

Polinices duplicatus Say. 

Calliostoma mitchelli (Conrad). 

Fissuridea sp. cf. specimen from Darlington, S. C. 

Cadulus thallus (Conrad). 

Nuculana acuta (Conrad). 

Glycymeris subovata tuomeyi Dall? 

Eontia trigintinarea (Conrad) MacNeil (identified by

MacNeil).

Ostrea sculpturata Conrad.

Pecten cf. P. eboreus eboreus Conrad (fragments). 

Plicatula marginata Say. 

Crassinella galvestonensis Harris. 

Venericardia granulata Say var. 

Venericardia perplana abbreviata Conrad. 

Cardita arata verdevilla Gardner. 

Phacoides crenulatus Conrad.

*Phacoides trisulcatus multistriatus Conrad. 

Semele subovata (Say) var.

*Gemma magna Dall. 

Corbula inaequalis Say. 

Mulinia congesta Conrad (a large form).

Fossils that appear to be at the same horizon as those 

of the Biggs bed occur in North Carolina in Greene

Feet 

60-

55-

50-

45- 

40- 

35- 

30- 

25-

20-

15 

IO

5

stocene

0) 

Q.

<D

c

1^

Bed Z 

Bed Y 

BedX

BedW

Bed V

V

1

J

.Zone 2

Zone 1

FIGURE 2.—Section on shore of the James River, east of >old Kings Mill 

Wharf, Va.

County, 8 miles northwest of LaGrange (U. S. G. S. 

sta. 11822); in Wayne County, 1% miles east of 

Fremont (sta. 11836); and in Craven County, at Eock 

Landing, on the right bank of the Neuse Eiver 16a/2 

miles above Newbern (sta. 10898). The localities in 

Greene and Wayne Counties indicate that the upper 

Yorktown, with a cooler-water fauna, transgressed a 

considerable distance inland.22

Sections in the Yorktown formation.—A line of 

bluffs on the north shore of the James River 6% to 7 

miles southeast of Williamsburg exposes the upper part 

of zone 1 and the lower part of zone 2 of the Yorktown 

formation. The best section, in a bluff about half a 

mile east of the old Kings Mill Wharf (1% miles

22 Mansfield, W. C., The Chesapeake Miocene basin of sedimentation 

as expressed in the new geologic map of Virginia: Washington Acad. 

Sci. Jour., vol. 19, p. 266, fig. 2, 1929.

northwest of the old Grove Wharf), is represented in 

figure 2. Bed v is the upper part of zone 1; bed w 

is the lowest part of zone 2; beds a?, y, and 0 the remainder of the lower part of zone 2. A list of the 

more common fossils found here and of the less 

common ones that are useful in zonal differentiation 

is given below:

Zone 1 (bed v) : 

Mollusks:

Conns marylandicus Green (rare).

Scaphella (Aurinia) mutabilis (Conrad) (rare).

Fusinus propeparilis Mansfield (rare).

Turritella pilsbryi Gardner.

Crucibulum grande (Say) (rare).

Glycymeris subovata plagia Dall.

Ostrea disparilis Conrad (rare?)

Pecten jeffersonius Say.

Pecten clintonius Say (occurs in the lower part of the 

bed).

Modiolus pulchellus Olsson.

Astarte undulata vaginulata Dall.

Astarte undulata deltoidea Gardner.

Astarte exaltata Conrad (common).

Crassatellites undulatus cyclopterus Dall.

Venericardia granulata Say.

Phacoides anodonta (Say).

Cardium virginianum Conrad (rare).

Isocardia Carolina Dall (rare).

Chione cortinaria (Rogers) (rare).

Kuphus calamus H. C. Lea. 

Coral: "

Septastrea marylandica (Conrad). 

Zone 2 (beds w to z): 

Molluslrs:

Turritella alticostata Conrad (rare).

Calliostoma philanthropum (Conrad) (rare).

Fissuridea redimicula (Say) (rare).

Area (Noe'tia) incile Say.

Area (Striarca) centenaria Say.

Ostrea sculpturata Conrad (rare).

Pecten decemnarius Conrad (rare).

Pecten virginianus Conrad (rare).

Pecten jeffersonius edgecombensis Conrad.

Astarte coheni Conrad (rare)?

Astarte undulata Say.

Astarte arata Conrad (rare).

Crassatellites undulatus (Say),

Chama congregata Conrad.

Cardita arata (Conrad) (rare).

Venericardia granulata Say.

Mulinia congesta (Conrad) (occurs near the top of

zone 2). 

Corals:

Astrangia lineata (Conrad).

Septastrea marylandica (Conrad) (occurs in the lower 

part of zone 2).

The type section of the Yorktown formation is exposed in a series of bluffs along the south shore of the 

York River within 2 miles southeast of the ferry landing. (See fig. 3.) Only the beds of zone 2 are exposed in these bluffs. A notable structural feature is 

the northwestward dip, contrasting with the normal 

regional dip to the east or southeast. Beds a to d are
10 MOLLITSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

part of the lowest unit of zone 2, and beds e and / are 

the middle unit. Farther upstream (west), beyond 

the section shown in the diagram, are exposures assigned 

to the upper unit of zone 2.

The following lists indicate the more common and 

more significant species of fossil organisms found in 

the beds of the Yorktown formation shown in figure 3.

Beds a and 6:

"Drillia" lunata (H. C. Lea). 

Oliva sayana Ravenel. 

Lirosorna sulcosa (Conrad). 

Fusinus exilis (Conrad). 

Ptychosalpinx altilis (Conrad). 

Ptychosalpinx laqueata (Conrad). 

Scalaspira strumosa Conrad.

Semele subovata (Say). 

Mulinia congesta (Conrad). 

Panope reflexa (Say). 

Bed f:

Caecum stevensoni Meyer.

Glycymeris amerieana (De France).

Ostrea disparilis Conrad.

Pecten jeffersonius edgecombensis Conrad.

Plicatula marginata Say.

Crassatellites undulatus (Say).

Venericardia granulata Say.

Astarte coneentrica Conrad.

Venus tridacnoides Lamarck.

About 2y2 miles above Yorktown an exposure reveals 

alternating beds of clay and marl carrying entire and 

broken shells. These beds lie stratigraphically above

YORKTOWN

j NW

Pleistocene(TaIbot) terrace deposit- Bed f

Pleistocene (Penholoway) terrace deposit

Bed e

i Mile

FIGURE 3.—Diagrammatic representation of the beds of zone 2 of the Yorktown formation within 2 miles southeast of Yorktown, Va.

Turritella alticostata Conrad (abundant).

Crepidula aculeata costata Morton.

Calliostoma philanthropum (Conrad).

Calliostoma virginicum (Conrad).

Fissuridea rediniicula (Say).

Yoldia laevis (Say).

Area (Noe'tia) incile Say.

Ostrea sculpturata Conrad.

Pecten jeffersonius edgecombensis Conrad.

Pecten virginianus Conrad.

Pecten decemnarius Conrad.

Phacoides (Lucinoma) contractus (Say).

Cardium virginianum Conrad.

Dosinia acetabulum Conrad.

Callocardia sayana (Conrad).

Kuphus calamus (H. C. Lea). 

Bed c:

"Drillia" pyrenoides Conrad.

Turritella alticostata Conrad.

Crepidula aculeata costata Morton.

Crepidula plana Say.

Fissuridea redimicula (Say).

Area (Striarca) centenaria Say.

Area (Noe'tia) incile Say.

Ostrea sculpturata Conrad.

Pecten jeffersonius edgecombensis Conrad.

Crassatellites undulatus (Say).

Crassinella galvestonensis Harris.

Venericardia granulata Say.

Venus plena (Conrad).

Pleiorytis centenaria (Conrad). 

Bed e:

Glycymeris subovata (Say).

Pecten jeffersonius edgecombensis Conrad.

Astarte symmetrica Conrad.

Crassatellites undulatus (Say).

Crassinella galvestonensis Harris.

Venericardia granulata Say.

Cardium acutilaqueatum Conrad.

the Yoldia bed of Harris, and the fauna is closely related to that in the beds at Suffolk, the uppermost unit 

of zone 2. The species collected here are as follows:

Conus marylandicus Green.

Turritella alticostata Conrad.

Crepidula fornicata (Linnaeus).

Polynices heros (Say)?

Glycymeris subovata (Say).

Glycymeris amerieana (DeFrance).

Area incile Say.

Pecten eboreus yorkensis Ball.

Pecten jeffersonius edgecombensis Conrad.

Plicatula marginata Say.

Astarte symmetrica Conrad.

Astarte undulata Say.

Cardita arata (Conrad).

Venericardia granulata Say.

Rangia clathrodon (Conrad).

Venus rileyi Conrad.

The stratum at water level between Indian Field 

Creek and Felgates Creek is the same stratum that 

crops out at the foot of the bluff along the James Kiver 

between old Kings Mill Wharf and old Grove Wharf 

and is stratigraphically lower than the basal bed below 

Yorktown. This stratum (part of zone 1) was observed for a short distance only, at one place, between 

the mouths of the two streams. Here it arches 2 or 3 

feet above the shore.

Near Felgates Creek the beds stratigraphically above 

the basal bed assume the regional dip to the east. The 

material consists of coarse-grained glauconitic sand 

and contains well-preserved and fragmentary shells. 

This fauna is heterogeneous, including St. Marys, 

Yorktown, and perhaps later species, and indicates re-
PART 1. PELECYPODA 11

deposition of an earlier fauna in later sediments. The 

species have, therefore, little value for correlation.

These observations of the bluffs were made before 

the new Yorktown-Williamsburg road (which parallels 

these bluffs) was constructed. On my last visit there 

(1936) I was unable to find the former bluff at Bellefield and assumed that it had been leveled down in 

the process of landscaping. Along a creek that the 

new road crosses about iy2 miles east of Williamsburg 

I observed zone 1 of the Yorktown formation in the 

stream bed and above it the <7A«m«-bearing bed, these 

units exhibiting the same relationships as in the bluffs 

below old Kings Mill Wharf.

MIOCENE STRATA OF NORTH CAROLINA

The St. Marys formation is doubtfully recognized in 

the northern part of North Carolina. It is probably 

exposed at very low stages of some of the streams, 

though certain identification has not been made.

The Yorktown formation, on the other hand, is 

widely exposed in the northern part of the State. . Apparently the whole formation is represented, though it 

is not easy to place all the exposures exactly within the 

formation. It contains a fauna suggestive of deposition in colder water than that of the Miocene beds in 

the southern part of the State.23 The cold-water fauna 

apparently lived in an embayment whose waters transgressed the older rocks of the Piedmont Plateau; the 

fauna, especially that near the inner shore line, was 

consequently somewhat protected from the influence of 

the warmer oceanic waters that lay east of the 

embayment.

In the southern part of the Coastal Plain the Duplin 

marl, uppermost Miocene, equivalent to the uppermost 

part of the Yorktown formation, occurs in patches,- as 

at Natural Well. The formation contains a fauna suggestive of deposition in warmer water than that of corresponding deposits farther north in North Carolina 

and Virginia.

The Miocene rocks, as exposed, probably do not anywhere exceed 50 feet in thickness.

YORKTOWN FORMATION

The beds assigned to the Yorktown formation are 

for convenience grouped into units lettered A to F, A 

being the lowest and F the highest. Groups A to C 

are well shown in the section on the Meherrin River 

near Murfreesboro, Hertford County, which follows:

Section of right bank of Meherrin River one-eighth mile above 

highway bridge and extending up ravine to Murfreesboro, 

Hertford County, N. C.

Pleistocene: Blue fine-grained sandy laminated clay bed 

containing mica flakes, with pebbles at the base 2 inches 

in diameter (thickness estimated)_____________ 20

te Mansfield, W. C., The Chesapeake Miocene basin of sedimentation 

as expressed in the new geologic map of Virginia: Washington Acad. 

Sci. Jour., vol. 19, No. 13, p. 266, fig. 2, 1929.

Section of right bank of Meherrin River one-eighth mile above 

highway bridge and extending up ravine to Murfreesboro, 

Hertford County, N. C.—Continued

Unconformity. 

Miocene:

Yorktown formation, zone 2: Feet 

Bluish to gray sands with shell impressions——— 4 

Bluish to gray clayey sands containing many 

Mulinia congesla, especially near the base and 

top. The following species were collected near 

the top of this 12-15 foot bed: Fissuridea cf. 

specimens from Suffolk, Va., Glycymeris subovata tuomeyi Dall, Pecten jeffersonius Say, 

Pecten eboreus eboreus Conrad, Crassatellites 

undulutas Say, Phacoides crenulatus Conrad, 

Venus tridacnoides (Lamarck), Mulinia congesta Conrad________——__———————— 12-15 

Brownish coarse sands containing dark particles 

and a few pebbles 1 inch or less in diameter. 

Ostrea is the most common fossil———————— 3 

Clayey sands, sparsely fossiliferous. The following species were collected above zone 1: Urosalpinse trossulus Conrad, Lirosoma sulcosa Conrad, *Turritella alticostata Conrad (like form 

from C7wMna-bearing bed below old Kings Mill 

Wharf, James River, Va.), Crepidula aculeata 

costata Morton, Fissuridea redimicula Say, 

Solarium nupcrum Conrad, Dentalium attenuatum Say, Mytilus conradinus D'Orbigny? 

*Astarte arata Conrad, Venericardia granulata 

Say, Chama congregata Conrad, Phacoides contractus Say, *Venus tridacnoides Lamarck, 

Mulinia oongesta Conrad. Those with an asterisk (*) came from that part of the bed 

directly above zone 1____________—__ 3 

Yorktown formation, zone 1: Soft medium-grained 

greenish-gray sand, oxidizing to light yellow, containing many black particles; contains Pecten clintonius in great numbers, also Isocardia, but no 

Mulinia congesta. The following species were collected from the basal bed (zone 1): Glycymeris 

subovata tuomeyi Dall, Pecten jeffersonius Say, 

Pecten clintonius Say, Ostrea disparilis Conrad, 

Phacoides contractus murfreesboroensis Mansfield, 

Astarte hertfordensis Gardner, Astarte undulata 

deltoidea Gardner, Venericardia granulata Say, 

Isocardia Carolina Dall_________________ 4

Groups A and B.—At . Murf reesboro (see stratigraphic section), on the Meherrin Eiver, zone 1 of the 

Yorktown formation forms the lower bed (group 

A) and is directly overlain by a bed (group B) corresponding to the bed in the lowest part of zone 2 that 

contains many Chama in the cliffs below old Kings 

Mill Wharf on the James Eiver, Va. A similar fauna 

occurs around Halifax, at Bell's old bridge over the 

Tar Eiver, Edgecombe County; and at several other 

places in North Carolina.

Group 0.—The highest beds (group C) in the section at Murfreesboro contain the latest identifiable 

fauna (U. S. G. S. sta. 10225) in the bluff. Beds that 

carry a similar fauna, although all may not be exactly 

at the same horizon, are found at the following localities: 

6.8 miles below Murfreesboro (sta. 11225) ; in Edge-
12 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

combe County, at Shiloh Mills, on the Tar Eiver above 

Tarboro (sta. 10911); in Pitt County, at Greenville (sta. 

10918) and 1% miles west of Greenville (sta. 11232). 

The fauna at most of the above-named localities includes 

Pecten jeffersonius, Pecten eboreus eboreus, Astarte un~ 

dulata (like the form occurring in the Cl^ima-bearing 

bed), and many individuals of Mulinia congesta. No 

specimens of Astarte arata or A. Toanokensis were noted 

in these faunas. The position of the fauna as a whole at 

these localities ranges from the (7Aama-bearing bed up 

to the fragmental series as exposed in the bluffs at 

Yorktown—that is, the lower and middle parts of 

zone 2 of the Yorktown formation of Virginia.

Group D.—The faunas at the following localities are 

very similar in character and appear to represent 

about the same horizon: Lower bed at Colerain Landing, Chowan Eiver; bed along Tar Eiver about 6 miles 

below Greenville (sta. 10916); bed about 1 mile north 

of Grimesland, Pitt County (sta. 11835), and beds in 

the vicinity of Chocowinity, Beaufort County (sta. 

11837). / In these faunas Turritella variabilis var. is 

common; Pecten eboreus eboreus is also very common; 

P. jeffersonius edgecombensis is rare; Astarte berryi is 

present at two or three localities.

The horizon of the faunas is believed to be about the 

same as that of the becls at Suffolk, Va., or at a somewhat lower horizon—that is, essentially the upper part 

of zone 2 of the Yorktown formation of Virginia.

Group E.—The fossils collected at Eock Landing 

and at other localities in North Carolina are regarded 

as a little younger than those in the beds of group D. 

The localities are mentioned under the discussion of 

the bed at the Biggs farm in Virginia (p. 8).

Group F, bed at Mount Gould Landing.—In eastern North Carolina, along the Chowan Eiver in Bertie 

and Hertford Counties and in Martin County, a marl 

bed crops out that is believed to have been deposited 

during the time of the last invasion of the Miocene sea 

into this part of the State. Its deposition appears to 

have succeeded closely that of the bed at the Biggs 

farm in Virginia, and it is therefore a little higher 

stratigraphically than the highest part of the Yorktown in Virginia. The bed at Mount Gould Landing 

contains a cooler-water fauna than that of the Duplin 

marl to the south but in age is nearly contemporaneous 

with some part of the Duplin, perhaps with that part 

deposited south of the Cape Fear Eiver in Eobeson 

and Bladen Counties, which appears to represent 

rather late Duplin time. Stratigraphically group F is 

placed in the uppermost part of zone 2 of the Yorktown 

formation.

The type exposure is in the right bank of the 

Chowan Eiver about three-quarters of a mile below 

Mound Gould Landing, Bertie County, where the bed 

rises about 10 feet above the beach and is unconformably overlain by about 25 of cross-bedded sand 

and clay.

The species collected from the type locality (U. S. 

G. S. sta. 11999) are as follows:

Acteocina canaliculata Say.

Mangilia aff. M. magnoliana Olsson.

Marginella limatula Conrad.

Marginella bella Conrad.

Olivella mutica Say.

Oliva nitidula (Dillwyn).

Scaphella mutabilis Conrad.

Busyeon canaliculatum canaliferum Conrad.

Uzita chowanensis Gardner.

Ilyanassa granifera sexdentata Conrad.

Anachis milleri Gardner.

Seila adamsi (H. C. Lea).

Turritella variabilis Conrad (stout variety).

Crepidula fornicata cymbaeformis Conrad.

Nueula proxima Say.

Nuculana acuta (Say).

Glyeymeris subovata Say.

Eontia carolinensis (Conrad).2*

Area improeera Conrad.

Ostrea sculpturata Conrad.

Pecten eboreus bertiensis Mansfield.

Modiolus ducatellii Conrad.

Astarte concentrica Conrad.

Crassatellites undulatus Say.

Venericardia granulata Say (a low form).

Phacoides multistriatus Conrad.

Callocardia sayana Dall.

Tellina declivis Say.

Cumingia medialis Conrad.

Spisula delumbis Conrad?

Corbula inaequalis Conrad. ^

Panope goldfussii Wagner, var.

The most characteristic species in this bed are Eontid 

carolinensis (Conrad) and Pecten eboreus bertiensis 

Mansfield.25

No specimens of Mulinia congesta Conrad were collected at Mount Gould Landing. This species is rare 

at this horizon, as only about half a dozen specimens 

are in the National Museum collection from Tar Ferry 

(sta. 11230). The specimens of the genus Spisula are 

more common. No specimens of Dentalium carolmense 

Conrad were collected in deposits referred to this horizon in Bertie, Hertford, and Martin Counties. Other 

localities at which the fauna of group F occurs are 

station 13814, upper bed at Colerain Landing (not the 

lower 3-foot bed in the bluff), Bertie County; station 

11230, Tar Ferry, Wiccacon Creek, Hertford County; 

station 13798, upper bed at Beaver Dam, Martin 

County; station 12004, Poplar Landing, Martin 

County; station 11833, near Shelmerdine and station 

11827, Hanrahan, Pitt County. Most of the species 

near Shelmerdine and Hanrahan are poorly preserved. 

The fauna in Pitt County includes, besides other forms,

2* Identified by F. S. MacNeil.

25 Mansfield, W. C., A new species of Pecten from the upper Miocene 

of North Carolina: Washington Acad. Sci. Jour., vol. 27, No. 1, pp. 

10-12, 1937.
PART 1. PELECYPODA 13

many individuals of Spisula and one fragment of 

Dentalium, carolindnse Conrad.

DUPLIN MARL

The Duplin marl includes deposits that occur in thin 

patches in Duplin, Sampson, Bladen, a^id Robeson 

Counties, in the southern part of North Carolina. The 

fauna is suggestive of deposition in warmer water than 

that of the Yorktown formation, though it is fairly 

sure that the beds containing Duplin fauna were contemporaneous with the upper part of zone 2 of the 

Yorktown of Virginia.

PLIOCENE STRATA OF NORTH CAROLINA

In the eastern part of North Carolina the Croatan 

sand is exposed in the right bank of the Neuse Kiver 

2 to 15 miles below Newbern and in Onslow'County 

and contains well-preserved fossils.26

In the southern part of the State abundantly fossiliferous strata of the Waccamaw formation overlie Cretaceous beds at Neills Eddy Landing, at Walkers Bluff 

on the Cape Fear River,27 and elsewhere.

GEOLOGIC RANGES OF CERTAIN SPECIES

Table 2 shows, so far as known, the geologic ranges 

of species of mollusks in deposits in Virginia and 

North Carolina extending in age from the medial Miocene (Calvert formation) to the Pliocene (Waccamaw 

formation).

In preparing this table I have had before me a table 

prepared by Miss Julia Gardner with a list of the 

species and the locality or localities at which they 

occur. The localities given in Miss Gardner's table 

do not indicate, at localities where there is more than 

one horizon, the positions in the sections at wjiich the 

species were taken, as at the time the collections were 

made, either the different stratigraphic units as now 

interpreted were not recognized, or stratigraphic information concerning the material was not recorded.'

During my field work in Virginia and North Carolina I collected fossils from each bed or fauna! unit 

in the sections, and relying in part upon the information thus obtained I have endeavored to interpret the 

range of the species in Miss Gardner's table. However, I have relied mainly upon her identification of 

species and record of localities at which they are 

•reported to occur.

Under these circumstances it is impracticable to divide in the table zone 2 of the Yorktown formation

26 Mansfield, W. C., Notes on Pleistocene faunas from Maryland and 

Virginia and Pliocene and Pleistocene faunas from North Carolina: 

U. S. Geol. Survey Prof. Paper 150, pp. 129-133, 1928; Additional notes 

on the molluscan fauna of the Pliocene Croatan sand of North Carolina : 

Jour. Paleontology, vol. 10, No. 7, pp. 665-668, 193G.

27 Miller, B. L., Tertiary formations: North Carolina Geol. and Econ. 

Survey, vol. 3, pp. 256-258, 1912.

into lower, middle, and 'upper parts; consequently 

zone 2 in Virginia includes the species that range 

through deposits "from the 6"Aam#-bearing bed (lower 

part of zone 2) to the beds at and in the vicinity of 

Suffolk (upper part of zone 2).

For North Carolina, zone 2 includes species ranging 

from the ^Aama-bearing bed to the top of the Yorktown formation. The geographic separation of the 

Yorktown formation, carrying a colder-water fauna, 

from the Duplin marl, carrying a warmer-water fauna, 

is shown by line c-c on the map included in my paper 

of 1929.28

The faunas at Neills Eddy Landing and Walkers 

Bluff on the Cape Fear River 29 are placed in the Pliocene Waccamaw formation. Certain beds at Wilmington are now considered of Pliocene age.30

The observed geologic ranges of a few important 

species that are not included in table 2 are shown in 

the following list:

Terebra (Hastula) simplex Conrad— 

Conus diluvianus Green____________

Conus marylandicus Green_—___.

Oliva eboreus Conrad__—________

Busycon coronatum Conrad_________

Busycon coronatum rugosum Conrad.

Busycon maximum fllosum Conrad_- 

Fusinus parilis Conr.ad_—_—_____ 

Fusinus propeparilis Mansfield-—___ 

Alectrion peralta Conrad___—_____ 

Turritella plebeia Say_________

Turritella plebeia carinata GardnerTurritella pilsbryi Gardner———__. 

Turritella terstriata Rogers________

Galliostoma humile Conrad______.

Glycymeris tumulus (Conrad)—__. 

Glycymeris americana Defrance___.

Area incile Say—————_—————.

Area idonea Conrad-—__—_—____

Area virginiae Wagner_____________

Pedalion maxillatum (Deshayes)___

Astarte perplana Conrad—_ 

Astarte symmetrica Conrad.

Cardium taeniopleura Dall_ 

Chione dalli Olsson_—_____

St. Marys.

Do. 

Yorktown, zone 1 and

higher beds. 

St. Marys.

Do. 

Calvert, Choptank, and St.

Marys.

Yorktown and higher beds. 

St. Marys. 

Yorktown, zone 1. 

St. Marys. 

Calvert, Choptank, and St.

Marys. 

St. Marys. 

Yorktown, zone 1.

Do.

St. Marys.

Not above the St. Marys. 

Yorktown, zone 2 and

higher beds. 

Yorktown, Chamd^bearing

bed and higher beds. 

St. Marys.

Do. 

Calvert, Choptank, St.

Marys, mechanically

mixed with zone 1 of

Yorktown. 

St. Marys. 

Yorktown, zone 2, middlf

and upper parts. 

Yorktown, zone 2. 

St. Marys.

28 Mansfield, W. C., The Chesapeake Miocene basin of sedimentation 

as expressed in the new geologic map of Virginia: Washington Acad. 

Sci. Jour., vol. 19, p. 266, fig. 2, 1929.

29 Miller, B. L., Tertiary formations ; North Carolina Geol. and Econ. 

Survey Kept., vol. 3, pp. 256-25.8, 1912.

30 Mansfield, W. C., Additional notes on the molluscan fauna of the 

Pliocene Croatan sand of North Carolina : Jour. Paleontology, vol. 10, 

pp. 665-668, 1936.

401033—43-
TABLE 2.—Geologic ranges of species

Yoldia laevis (Say) ._ __ _ _ _ _ _ _ _ _ _ _ ___ __-

A T*l"*f} f Slf^QY^ll Q Tf*Q "^ SPftloT1 ! S fV^TlTfl H

Pecten (Amusium) mortoni RaveneL- _- _,

Thracia transversa H. C. Lea _ _ __- _ -- - ___

Astarte (Ashtarotha) concentrica bella Conrad ______ _ _____

Crassinella lunulata harrisi Gardner, n. subsp ________ _______

Virginia

Calvert

(?) 

X

X

Choptank

(?) 

X

X

X

St. Marys

Zone 1

X

X

X

X

(1)

Zone 2

X

X

X

X

X

X

X

1 X

Undifferentiated

X

Yorktown

Zone 1

X

'

X

(?)

(?)

X

X

(?)

X 

X 

X

(?)

X

Zone 2

X 

X

X 

X 

X

X

X

X

X

X

•x

X

X , 

X 

X 

X

X 

X 

X

(?)

X

X

X 

X

X

X 

X

X 

X

Undifferentiated

X

^

Yo

Zone 1

X

X

X

X

X 

X 

X

X

Zo

-

•
Erycina carolinensis Dall _ _ _ _ _

Cardium (Cerastoderma) virgimanum Conrad _ _ _

Cardium (Laevicardium) sublineatum Conrad _ _

Isocardia fraterna Say_

Petricola (Rupfillaria) grinnelli Olsson

Cooperella carpenter! Dall _

Callocardia (Agriopoma) chioneformis Gardner, n. sp _

Chione (Timoclea) grus (Holmes) ______ __ __>____

Venus (Mercenaria) plena inflata Dall

Gemma magna insulcata Gardner, n. subsp

Gemma magna maiorina Gardner, n-. subso _ _ _ _

•

v

v

v

N X

X •

X

~

•

(?)

X

X

(?)

X

X

X

X

X

(?)

(?)

X

(?)

X

X

X

X

X

X

X

2 X

X

X

X

X

X

X

X

X

X

(?)

X

X

X

X

X

X

X

X

X

X

(?)

(?)

(?)

X

(?)

Fide Gardner. * Collected near Franklin by Mansfield.
16 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

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trt-O 

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So

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N

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rfl c3

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-

X

XX

X

X

S

e£

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Gemma virginiana Dall_. magna (Moerella?) Gardn Tellina capix (Moerella) Tellina (Deshaye sayi

Conrad Tellinfa eeen

X

XXX

X

xxxx

X

X

ft

OQ

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03

X

xxxxxx

XX

XXX

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T3 '*~! r^ -£J "^ C^ 

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03 03 03 OQ X! P! -^

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Abra aequalis deltoidea Gardner, Tagelus (Spengler) gibbus___ _ .Tagelus gibbu(Con carolinensis 

Donax emmonsi preaequilibrata < 

Donax Sav fossor 

XX

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Donax chuckatuckensis Gardner, 

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X

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(H~a

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G, ecursor Gardne is ,v)_______

X

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fts • ^

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GO (Conrad) . Gard altalockensis

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Mactra (Mactrotoma

isula (Mactromeris isula (Hemimactra) isula (Hemimactra) (Hemimactra) isula (Hemimactra) isula 

ft ft ft ft ft

OQOQOQGQ02

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PART 1. PELECZPODA 17

LOCALITIES IN VIRGINIA AND NORTH CAROLINA

The numbers assigned to the key localities in the list 

that follows correspond to those on the index map, 

figure 4. On the index map the numbers are arranged 

serially, beginning with the northernmost localities in 

Virginia and progressing southward. The numbers 

within each county are likewise arranged from north'to 

south.

Virginia:

Westmoreland County:

1. Horsehead, Stratford, and Nomini Cliffs. 

Northumberland County:

2. 8184, east bank of Hull Creek. 

Richmond County: „

3. Carter Wharf, 1% miles west of.

4. Farnham, 2% miles south of.

5. Union Mill. 

Essex County:

6. Bowlers Wharf, 1 to 2 miles below and 2% miles 

below.

7. Jones Point, a quarter of a mile above. 

Middlesex County:

8. Urbanna.

9. Burhans Wharf. 

King and Queen County:

10. Walkerton, 3 miles northeast of. 

New Kent County:

11. Lanexa. 

James City County:

12. Kings Mill Wharf. 

York County:

13. Yorktown, three-quarters of a mile above.

14. Bellefield. 

Gloucester County:

15. Ware River. 

Prince George County:

16. Near mouth of Baileys Creek. 

Surry County:

17. Claremont, old Claremont Wharf, Claremont

Wharf, 6% miles below Claremont, Sunken

i Marsh Creek 2 miles below Claremont, and S1^

miles below Claremont Wharf (probably

Schmidts Bluff).

18. Schmidts Bluff.

19. Scotland Wharf.

20. Cobham Wharf.

Dinwiddie County:

21. Petersburg.

Isle of Wight County:

22. Smithfield, 2 miles northwest of, 1% miles west of, 

three-quarters of a mile northeast of, 1% miles 

northeast of, and 5 miles northeast of.

23. Benns Church.

24. Zuni, 1% miles above, 2% to 3 miles northwest of, 

6% to 7 miles below, 7 to 7% miles below, and 

8 to 8% miles below. 

Greensville County:

25. Hitchcock. 

Southampton County:

26. Biggs farm.

27. Delaware Park.

28. Sycamore Church. 

Nansemond County:

29. Chuckatuck, a quarter of a mile north of.

30. Everets, a quarter of a mile east of.

Virginia—Continued.

Nansemond County—Continued.

31. Exit.

32. Reids Ferry, 1% miles southeast of.

33. Suffolk, 5% miles northwest of, 2% miles northwest of, 1% miles northwest of, 1% miles north 

of, 1% miles north of, 1 mile west of, half a 

mile below the Suffolk waterworks dam, 1 mile 

northeast of Suffolk, 1% miles northeast of 

Suffolk, 1% miles southeast of Suffolk.

34. Drainage ditch of Norfolk & Western Railway

just east of Jericho ditch. 

North Carolina:

Halifax County:

35. Halifax, Durham's farm, near Halifax.

36. Palmyra Bluff, 3y2 miles below. , Northampton County:

37. Branches Bridge, 1% miles above, 1 mile above

and 1% to 2 miles below. 

Hertford County:

38. Murfreesboro, near Murfreesboro, 1 mile above. 

1% miles above, and 2% miles northwest of.

39. Tar Ferry, above Tar Ferry, l1^ miles below and

3 to 4 miles below. 

Bertie County:

40. Colerain Landing.

41. Mount Gould Landing.

42. Edenhouse Point, half to three-quarters of a mile

above. 

Edgecombe County:

43. Rocky Mount, 2 miles west of, S1/^ miles northwest 

of, and 6 to 7 miles below.

44. Bells Bridge, half a mile above, 15% miles above, 

an eighth of a mile below, and 1 to 1% miles 

below; New Bridge, two-thirds of a mile north 

of, 6% miles below, and 5 miles below.

45. Shiloh Mills.

46. Tarboro. 

Martin County:

47. Williamston, 3 miles west of, 4 miles northwest of, 

2% miles northwest of, and 1 mile northwest of.

48. Hamilton Landing, a third of a mile below and

2 miles southeast of. 

Wilson County:

49. Wilson, Hominy Swamp, 1 mile west of, 3 miles 

east-southeast of, 5 miles south of.

50. Stantonsburg, 1 mile northwest of. 

Pitt County:

51. Tugwell, 2 miles southeast of, and Toddy Station 

near Tugwell.

52. Standard, 2% miles north of.

53. Farmville, 1% miles northeast of and 3 mileb 

south of. '

54. Greenville, south of county bridge, 8 or 9_ miles 

west of Greenville, 3 miles west of Greenville, 

2 miles west of Greenville, 1% miles west of 

Greenville, l1/^ miles northwest of Greenville, 1% 

miles east of Greenville, 6 miles below Greenville 

at Cherry Landing, 6% miles below Greenville 

at Tafts Landing, 8 to 10 miles south of Greenville.

55. Grimesland, three-quarters of a mile north of.

56. Grifton, 3 miles east of. 

Beaufort County:

57. Chocowinity, 1% miles northwest of, 2 miles northwest of, 2% miles northwest of. 

Greene County:

58. Lizzie, half a mile east of, 1 mile east of, and 

4 miles east of (in Dog Swamp).

59. Castoria, 1 mile north of.
18 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

FIGURE 4.—Index map showing Miocene and lower Pliocene localities in Virginia and North Carolina. The numbers refer to the list on pages 17 and 19.
FASIT 1. PELOBCYPODA 19

North Carolina—Continued. 

Wayne County:

60. Goldsboro, 6 miles west of. 

Craven County:

61. Rock Landing. 

Sampson County: '

62. Clinton, 2% miles south of, 3 miles south of, and

4 miles south of. 

Duplin County:

63. Natural Well and environs.

64. Warsaw, 2 miles northeast of. 

Robeson County:

65. Lumberton, near the bottling works, 1 mile west 

of Lumberton, 2 miles below Lumberton, and 4 to

5 miles below Lumberton.

66. Fairmont, 1% miles northeast of, 4 miles north-

* east of, and Ashpole (near Fairmont). 

Bladen County:

67. Clarkton, 4 miles south of.

68. Elizabethtown, 4 miles south of, and 4 miles ^ast 

of.

69. Walkers Bluff.

70. Black Rock Landing. 

Columbus County:

71. Cronly.

72. Neills Eddy Landing.

73. Lake Waccamaw. 

New Hanover County:

74. Wilmington, city rock quarry near Wilmington.

SYSTEMATIC DESCRIPTIONS

By JmiA GARDNER 

Phylum MOLLUSCA

Class PELECYPODA 

Order PRIONODESMACEA 

Superfamily NUCTTLACEA

Family NUCUIIDAE 

* Genus NUCUIA Lamarck

1799. Nucula Lamarck, Prodrome d'une nouvelle classification

des coquilles: Soc. histoire nat. Paris M6m., p. 87. 

Type by monotypy: Area nucleus Linneaeus. Recent in the 

European seas. The group has been exhaustively treated by 

Schenck.31

Valves not gaping: shell nacreous in texture, small, 

trigonal to subcircular to elliptical. Umbones subcentral or posterior, proximate, opisthogyrate. Escutcheon, and more rarely the lunule, clearly indicated 

though not sharply defined. External surface commonly concentrically striate or rugose with a more 

or" less obvious subcutaneous radial lineation. Two 

series of crowded, chevron-shaped hinge teeth, the 

anterior the longer and the individual teeth diminishing rapidly in size along the margin of the chondrophore; the posterior series shorter and more uniform 

in size and direction. Chondrophore narrow, inclined

31 Schenck, H. G., The classification of nuculid pelecypods: Mus. royal 

histoire nat. Belgique MSm., vol. 10, No. 20, pp. 1-78, pis. 1-5, 1934.

obliquely forward. Anterior and posterior muscle 

scars subequal, inconspicuous. Pallial line simple. 

Inner margin finely crenate in harmony with the 

radial lineation.

Schenck 32 refers to Nucula s. s. the Lower Cretaceous 

species, Nucul-a gaultana, J. Starkie Gardner, and 

closely related forms earlier included under Nucula 

have been described from the Paleozoic. The wide 

distribution of the Recent species suggests a stock 

deeply rooted in the past. Though characteristic of 

the boreal and temperate oceans today, the group has 

also a meager representation in the tropical seas. It 

is found in both shallow and deep water and on both 

sandy and muddy bottoms.

Nucula proxima Say

Plate 1, figures 1, 2, 4, 5

1820. Nucula obliqua Say, Am. Jour. Sci., 1st ser., vol. 2, p. 40. 

Not Nucula obliqua Lamarck, 1819.

1822 (August). Nucula proxima Say, Acad. Nat. Sci. Philadelphia Jour.,. 1st ser., vol. 2, p. 270-.

1856. Nucula proxima Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 53, pi. 17, figs. 7-9.

1858. Nucula proxima Say. Holmes, Post-Pleiocene fossils of 

South Carolina, p. 17, pi. 3, fig. 6.

1889. Nucula, proxima Say. Ball, U. S. Nat. Mus. Bull. 37, p. 

42,, pi. 56, fig. 4.

3894. Nucula proxima Say. Whitfield, U. S. Geol. Survey 

Mon. 24, p. 50, pi. 7, figs. 7-10.

1898. Nucula proxima Say. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 4, p. 574.

190i. Nucula proxima Say. Glenn, Maryland Geol. Survey, 

Miocene, p. 398, pi. 108, figs. 5, 6.

1906. Nucula proxima Say. Clark, idem, Pliocene and Pleistocene, p. 207, pi. 65, figs. 1-4.

1932. Nucula proxima Say. Mansfield, Florida Geol. Survey 

Bull. 8, p. 30, pi. 1, figs. 3, 4, 5.

Valves obliquely subtriangular, obsoletely striate transversely, one or two of the striae more conspicuous; numerous, 

hardly perceptible longitudinal striae; anterior and posterior 

sides forming an acute angle; umbo obtuse; apex % acute; 

teeth angulated, prominent, cavity at the apex of the hinge 

profound, rather long; basal margin denticulatocrenate. 

Greatest length one-fifth of an inch.—Say, 1820.

If a geographical series of this species be examined, it will 

be noticed that the northern specimens are almost smoothly 

truncate behind, the escutcheon is not impressed to any marked 

degree, and there is no angle at the margin below the escutcheon. On the other hand, the specimens from the southern 

coast, whence Say's type was derived, have a thinner shell 

with an impressed escutcheon, the middle of which pouts more 

or less strongly; the valve margin below the escutcheon has a 

projecting angle; the shell is somewhat compressed, compared 

with the northern form, and has a paler a"hd more delicate 

epidermis. * * * Most of tihe conchologists of the United 

States having resided north of Delaware, the northern form Is 

the more familiar both in books and collections, but it is not 

the original type, and I have therefore given it a varietal 

name.—Dall, 1898.

32 Idem, p. 22.
20 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Type locality: Upper Marlboro, Md., is cited as tlie 

type locality. The collector was Mr. J. Gilliams, of 

Philadelphia, who submitted a specimen of a large 

species of fossil "Perna" later referred to Melina maxillata. The Nucula and several other species were taken 

from the. "compact earth" included between the two 

"Perna" valves. No record of Melina magdllata from 

the immediate vicinity of Upper Marlboro has since 

been published.

This exceedingly variable form is by far the most 

common Nucula of the east coast Miocene and (Pliocene. 

The range in the outline of the valves of the Recent 

species, coincident with the geographic range, has already been noted by Dall. One would scarcely expect 

to find, as is the case, that the contour characteristic 

of the northern inhabitants among the Recent species 

is, in the fossil representatives, limited for the most 

part to the late Miocene and early Pliocene forms of 

southern North Carolina.

The number of the hinge teeth varies with the age. 

It is not uncommon to find young forms with only 4 

posterior and 10 anterior teeth nor adults with 12 

posterior and 25 anterior teeth. The radial sculpture 

is another inconstant character, in both the number 

and the prominence of the impressed lines. These are, 

for the most part, visible only under magnification, but 

in occasional individuals they seem to be altogether 

wanting, while in others they may be readily noted with 

the naked eye.

A single valve, quite certainly an abnormal Nucula 

proxima Say, was collected one-third of a mile below 

Hamilton Landing. The shell is subquadrangular in 

outline, with almost terminal beaks, sharply truncated 

posteriorly, though rounded anteriorly.

The variety truncula, suggested by Dall, has not been 

separated from the true proodma, as the criteria which 

he gives—the outline, convexity, escutcheon characters, 

etc.—have proved in the material under investigation 

to bear no constant relation to one another.

Distribution: Virginia: Miocene, St. Marys formation (?) 

Nomini Cliffs, Westmoreland County'. St. Marys formation, 

Union Mills, 2% miles south of Farnham, Richmond County; % 

mile above Jones Point, 1 to 2 miles below Bowlers Wharf, Essex 

County ; Urbanna, Middlesex County. Yorktown formation. % 

mile above Yorktown, Yorktown, York County; 1% miles west of 

Smithfleld, Benns t Church, 1% miles below Blackwater Bridge, 

Blackwater River, Isle of Wight County; Hitchcock, Greensville 

County; a quarter of a mile north of Chuckatuck, Exit, % mile 

east of Everets, iy2 miles southeast of Reids Ferry, 1% miles 

north of Suffolk, 1% miles north of Suffolk, 5% miles northwest 

of Suffolk, 2y> miles northwest of Suffolk, 1 mile west of Suffolk, 

iy2 miles northeast of Suffolk, y^ mile below Suffolk waterworks dam, and drainage ditch of Norfolk & Western Railway, 

just below Jericho ditch, Nansemond County.

North Carolina: Miocene' Yorktown formation: 1 mile above 

Branches Bridge, iy2 miles below Branches Bridge, and 1% 

to 2 miles below Branches Bridge, Northampton County; Mur 

freesboro, iy2 miles above Murfreesboro, Tar Ferry, 1% miles

below Tar Ferry, 3 to 4 miles below Tar Ferry, Dogwood 

Landing, and Mount Pleasant Landing, Hertford County; Colerain Landing, Mount Gduld Landing, and % to % mile above 

Edenhouse Point, Bertie County; Palmyra Bluff, Halifax 

County; Hamilton Landing, % mile below Hamilton Landing, 

2 miles southeast of Hamilton Landing, 4 miles northwest of 

Williamston, and 2% miles northwest of Williamston, Martin 

County; 2 miles west of Rocky Mount, y2 mile above Bells 

Bridge, Shiloh Mills, and Tarboro, Edgecombe County; 2 miles 

below Toddy Station, 1*4 miles northeast of Farmville, 2*/3 

miles north of Standard, 3 miles southwest of Frog Level, 8 

to 9 miles west of Greenville, Hardee Creek, 3*A miles from 

Tar River, 1 mile northwest of Galloway Crossroads, Pitt 

County; 1 mile west of Wilson, Wilson County; 4 miles east 

of Lizzie, Greene County. Duplin marl, 4 miles south of Clinton, 

and 10 miles south of Clinton, Sampson County; J^atural Well 

and environs, Duplin County; 1% miles northeast of Fairmont, 

Robeson County. Pliocene, Waccamaw formation. Walkers 

Bluff, Bladen County; Lake Waccamaw, Cronly; and Neills 

Eddy Landing, Columbus County; city rock quarry, Wilniington, 

New Hanover County.

The species is common at most of these localities and in the 

environs of Hamilton Landing, N. C., is exceedingly abundant 

and practically the only form of. molluscan life represented.

Outside distribution: Miocene, Calvert formation, Shiloh, 

Jericho, and Bridgeton, N. J.; Church Hill, 3 miles west of 

Centerville, Fairhaven, Chesapeake Beach, Plum Point, and 

Trumans Wharf, Md. Choptank formation, Dover Bridge and 

Cordova, Md. Duplin marl, Darlington, Darlington County, 

S. C.; Porters Landing, Effingham County, Ga. Choctawhatcb.ee 

formation, northern Florida. Pliocene, Waccamaw formation, 

Nixons and Tillys Lake, Horry County, S. C. Caloosahatchee 

marl, Sanford, Seminole County, Fla.; Kissimmee, Osceola 

County, Fla.; Caloosahatchee River and Shell Creek, Fla.; 

Pleistocene, Dismal Swamp Canal, posts 15 to 16, Va.; quarantine station well, North Carolina; Wailes Bluff, near Cornfield 

Harbor, Md.; Simmons Bluff, Savannah River, S. C.; Rose Bluff, 

Nassau County, Fla.; Eau Gallie, Brevard County, Fla.; Daytona, 

Volusia County, Fla. Recent, Cape Hatteras to Charlotte Harbor, Fla., in 2 to 100 fathoms; variety trunculus Dall, from 

Nova Scotia south to Hatteras.

Nucula diaphana H. C. Lea

Plate 1, figures 3, 9

1846. Nucula diaphana H. C. Lea, Am. Philos. Soc. Trans., vol.

9, p. 243, pi. 34, fig. 26. 

1898. Nucula diuphana H. C. Lea. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 4, p. 577.

Shell transverse, inequilateral, subelliptic, rounded anteriorly 

and posteriorly, inflated, diaphanous, thin, smooth, polished, 

pearly within; umbonial slope somewhat flattened ; basal margin 

curved; dorsal margin curved; beaks prominent; teeth very 

arcuate, 5 anterior, 12 posterior; fosset rhomboidal, oblique; 

internal margin crenulated.

Diameter 0.04, length 0.11, breadth 0.15 inch.

This little shell, in common with the preceding [Nucula 

dolabella H. C. Lea] has some resemblance to the, N. obliqua 

Say, but it may be distinguished by its elliptical shape, thin and 

diaphanous substance, smooth surface, and' rhomboidal fosset 

The teeth are also more arcuate, and there is a greater disparity 

between the posterior and anterior series.

In outline, this species is closely allied to the N. antiqua 

Mighels and Adams, from the post-Pliocene of Massachusetts.— 

H. C. Lea, 1846.
PART 1. PELECYPODA 21

Lea's illustration is so very poor that it is impossible 

to be sure whether or not the specimen, No. 1591, from 

the Academy of Natural Sciences in Philadelphia, 

labeled ddaphana, and reproduced in figure 3, is that 

described and figured by Lea. The measurements 

closely correspond, and the species represented seems 

distinct from the common N. proximo, Say. It has 

not, however, been identified in the later collections. , Type locality: Petersburg, Va.

Family NUCUXANIDAE 

Genus YOLDIA Moller 

1842. Yoldia Moller, Index molluscorum Groenlandiae, p. 18.

Type by subsequent designation (Verrill and Bush, Am. 

Jour. Sci., 4th ser., vol. 3, p. 55, 1897) : Yoldia arctica Moller 

(not Gray) —YQldia hyperborea (Loven) Gould. Recent in the 

Arctic seas.

The genus differs from the old "Leda" in the 

posterior gape of the valves, the longer siphons, and 

the consequently deeper pallial sinus. It is more produced transversely and more markedly rostrate than 

the southern analog, Orthoyoldia Verrill and Bush, the 

length of the anterior and posterior series of teeth is 

more discrepant, and the chondrophore is relatively 

larger and higher.

Yoldia laevis (Say) Conrad

Plate 1, figure 10

1824. Nucula laevis Say, Acad. Nat. Sci. Philadelphia Jour., 1st 

ser., vol. 4., p. 141, pi. 10, fig. 5.

1831. Nucula laevis Say, American conchology, pi. 12, righthand figures, descriptive test.

1845. Nucula limatula Conrad, Fossils of the medial tertiary 

of the United States, p. 57, pi. 30, fig. 4. Not 

N. limatula Say, 1831.

1856. Nucula limatula Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 52, pi. 17, figs. 13-15. Not 

N. limatula Say, 1831.

1863. Yoldia laevis Say. Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, vol. 14, p. 581.

1864. Yoldia laevis (Say) Conrad. Meek, Miocene check list;

Smithsonian Misc. Coll., No. 183, p. 5. 

1894. Yoldia "limatula" Whitfield, U. S. Geol. Survey Mon. 24,

p. 51 (part), pi. 7, figs. 11, 12. 

1898. Yoldia laevis Say. Ball, Wagner Free Inst, Sci. Trans.,

vol. 3, pt. 4, p. 596. 

1904. Yoldia laevis (Say). Glenn, Maryland Geol. Survey,

Miocene', p. 397, pi. 108, figs. 3, 4.

Transversely elongate-subovate, rostrated, nearly smooth.

Shell compressed, thin, fragile, polished, smooth, slightly 

wrinkled toward the base; beaks nearly central, hardly prominent beyond the hinge margin, rounded, approximate; series 

of teeth subrectilinear, a little arcuated behind; teeth prominent ; hinge margin exteriorly both before and behind the beaks 

rather abruptly compressed; posterior margin rounded ; anterior 

margin somewhat rostrated, the anterior hinge margin 

rectilinear, very little reflected at tip; inner margin simple.

Length nearly half an inch, breadth nearly 1 inch—Say, 1824.

Type locality: Maryland.

The synonymy of this species gives evidence of the 

close resemblance to its Pleistocene and Recent descendant, Yoldia limatula (Say). TJie outlines of both 

forms vary widely, and little reliance can be placed 

upon this character. As a rule, however, the Tertiary 

species is relatively lower, more rostrate posteriorly, 

and with a less pronounced umbonal slope. The hinge 

teeth and the character of the chondrophore furnish 

the best distinctions. In Yoldia la&vis the teeth are 

more closely set and the series extends farther down 

toward the basal margin than in Yoldia limatula. In 

both forms the number of teeth varies with the age of 

the individual. The chondrophore of Yoldia laevis is 

more conspicuous and tends to be transversely 

elongated rather than subtriangular as in Yoldia 

limatula (Say).

The Tertiary species is common in the more northern localities but, like the Recent Yoldia, diminishes in 

prominence and finally disappears toward the south.

Distribution: Virginia: Miocene, Yorktown formation, Hitchcock, Greensville County; % mile above Yorktown, Yorktown, York County; Claremont Wharf, Surry County; Fergusons Wharf, 1% miles west of Smithfield, and 5 miles northeast 

of Smithfield; 1% miles below Blackwater Bridge, 2% to 3 

miles south of Zuni, 7 to 7y2 miles below Zuni, Isle of Wight 

County; 2 to 2% miles below South Quay, Blackwater River, *4 

mile north of Chuckatuck, y± mile east of Everets, Exit, 5% miles 

northwest of Suffolk, 2y2 miles northwest of Suffolk, 1% miles 

northwest of Suffolk; iy2 miles north of Suffolk, 1 mile west of 

Suffolk, y2 mile below the Suffolk waterworks dam, 1 mile northeast of Suffolk, and 1% miles northeast of Suffolk, Nansemond 

County.

North Carolina: Yorktown formation, 1 mile above Branches 

Bridge, ]% to 2 miles below Branches Bridge, and Branches 

Bridge, Northampton County; 2% miles northwest of Murfreesboro, l 1^ miles above Murfreesboro, 1 mile above Murfreesboro, Murfreesboro, Tar Ferry, and Mount Pleasant Landing, 

Hertford County; Durham's farm near Halifax, Palmyra Bluff, 

and 3y2 miles below Palmyra Bluff, Halifax County; Hamilton 

Bluff, ys mile below Hamilton Landing, 3 miles west of Williamston, 2y2 miles northwest of Williamston, and 1 mile northwest 

of Williamston, Martin County; 6 to 7 miles below Rocky Mount, 

5 miles below New Bridge, 15y2 miles above Bells Bridge, % mile 

above Bells Bridge, mouth of Swift Creek, and Shiloh Mills, Edgecombe County; 2 miles below Toddy Station, 3 miles southwest of 

Frog Level; 8 to 9 miles west of Greenville, 3 miles west of 

Greenville, 6 miles below Greenville, 6% miles below Greenville, 8 to 9 miles south of Greenville, and 9 to 10 miles south 

of Greenville, Pitt County; 1 mile west of Wilson, Wilson 

County; 1 mile east of Lizzie, % mile east of Lizzie, and 4 

miles east of Lizzie in Dog Swamp, Greene County; y2 to % 

mile above Edenhouse Point, Bertie County. Duplin marl, iy2 

miles northeast of Fairmont, Robeson County. Pliocene, 

Waccamaw formation, 4 miles south of Elizabethtown and 

Walkers Bluff, Bladen County.

Outside distribution: Miocene, Calvert formation, Jericho and 

Shiloh, Cumberland County, N. J.; Church Hill, Fairhaven, 

Parker Creek, Lyons Creek, Plum Point, and Whites Landing, 

Md. Hawthorn formation, Porters Landing, Savannah River, 

Effingham County, Ga. Choptank formation, Jones Wharf and 

Sand Hill, Md. St. Marys formation, Cove Point, St. Marys 

River, and Langleys Bluff, Md.
22 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Superfamily ARCACEA

Family ARCIDAE

1935 (August). Reinhart, P. W., Classification of the pelecypod 

family Arcidae: Mus. royal histoire nat. Belgique 

Mem., vol. 11, No. 13, pp. 1-68.

Genus ARCA (Linnaeus) Lamarck

17,58. Linnaeus, Systema naturae, 10th ed., p. 693. 

1799. Lamarck, Prodrome d'une nouvelle classification des coquilles: Soc. histoire nat. Paris M6m., p. 87.

Area noae Linnaeus, Recent in the Mediterranean, 

and the Area cited in the Prodrome, was long accepted 

as the type and has to its credit the authentic designations of Schmidt, 1818, and Gray, 1847. The citation 

of Schumacher, 1817 (Essai d'un nouveau systeme des 

habitations des vers testaces, p. 172), "Pour le type da 

genre j'ai donne la fig. 2, pi. XIX, de la charniere de 

VArca antiquata Lin. qu'on trouve figuree dans Chemn. 

7, pag. 201, tab. 55, fig. 548," may justly claim priority. 

As Reinhart 33 remarked, however, "It is a debatable 

question -whether Schumacher was here designating a 

type species or merely illustrating a type of hinge 

structure." A request that Area noae be established 

as the type species has been presented to the International Commission on Zoological Nomenclature by 

Reinhart.33 This stems on the whole a wiser method 

of salvaging a widely accepted type than an attempt 

to invoke "virtual tautonomy" in its behalf.

In the hope of a favorable decision from the commission Area noae has been retained as the type of 

the genus in this report.

The Areas typified by A. noae are equivalve, inequilateral, transversely elongate, rudely quadrate, or oval, 

commonly irregular in outline, and gaping anteriorly. 

The beaks are prominent, placed well forward and 

separated by a wide cardinal area scarred with oblique, 

discontinuous cartilage grooves. The radials that 

adorn the outer surface differ in prominence and spacing on different parts of the shell. The hinge line is 

straight; the teeth are numerous, short, subequal, and 

transverse. The adductor impressions are distinct, the 

pallial line is simple, and the inner margins are smooth 

or feebly crenate at the extreme edge in harmony with 

the radial ornamentation of the exterior.

Genus BARBATIA Gray

184^. Barbatia Gray, Synopsis of the contents of the British 

Museum, 44th ed., p. 81. Described but no species mentioned.t

1847. Barbatia Gray, Zool. Soc. London Proc., pt. 15, p. 197.

Type by subsequent designation, Gray, 1847: Area, barbata 

Linnaeus. Recent in the Mediterranean.

The Barbatia, are elongated shells, covered with a hairy 

periostraca; the teeth on the middle of the line are small, of 

the ends large and oblique.—Gray, 1842.

33 Eeinhart, P. W., op. cit., p. 16.

The shell of Barbatia, like that of Area, is usually of 

at least moderate dimensions, inequilateral, transversely 

elongate, with a byssal gape at the ventral margin, 

anterior or subcentral beaks, a multivincular ligament, 

numerous taxodont teeth, rather large muscle scars, a 

simple pallial line, and, as a rule, a crenate inner 

margin.

The shell is usually less deformed in Barbatia than 

it is in Area; the byssal gape is not so wide; the posterior 

portion of the shell is broadly rounded rather than 

rostrate; the beaks are less prominent and the cardinal area is @onsequently lower; the dentition is less 

regular than that of Area and is usually obliterated 

medially in the adult by the encroachment of the car- 

^dinal area. The shells of both genera are radially 

sculptured, but that of Barbatia, though irregular in 

many species, is less sharply differentiated on the 

anterior and posterior areas.

True Barbatia has been recognized in the Upper Cretaceous of the east coast and Gulf regions (Stephen-* 

son, 1923; Wade, 1926) and the genotype is a Recent

species.

Subgenus GRANOARCA Conrad

1862. Granoarca Conrad, Acad. Nat. Sci. Philadelphia Proc., vol. 

14, p. 290.

Type by inonotypy: Area propatiila Conrad. Miocene of Virginia and the Carolinas.

Barbatia (Granoarca) propatula (Conrad) Conrad

Plate 2, figure 1

1844. Area propatula Conrad, Acad. Nat. Sci. Philadelphia Proc., 

vol. 1, p. 323.

1845. Area propatula Conrad, Fossils of the medial Tertiary of

the United States, p. 61, pi. 32, fig. 1. 

1856. Area Mans Tuomey and Holmes, Pleiocene fossils of South

Carolina, p. 34, pi. 14, figs. 4, 5. Not Aroa hians Bronn,

1842, nor Reeve, 1844. 

1863. Barbatia, (Granoarca) propatula Conrad, Acad. Nat. Sci.

Philadelphia Proc. for 1862, vol. 14, p. 580. 

1898. Barbatia (Granoarca) propatula Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 627. 

1916. Area, propatula Conrad. Sheldon, Palaeontographica

Americana, vol. 1, No. 1, p. IS, pi. 4, fig. 1. 

1932. Barbatia (Granoarca) propatula Conrad. Mansfield,

Florida Geol. Survey Bull. 8, p. 43, pi. 4, figs. 1, 2, 3.

Rhomboidal, thick, and ponderous; posterior side produced; 

sides flattened, slightly concave toward the base; umbonial slope 

rounded, rather elevated; ribs about 32, square, not profoundly 

prominent, about equal in width to the interstices, which have 

transverse imbricated lines; ribs largest about the umbonial 

slope, very distinct on the posterior slope, which is concave 

toward the hinge line; posterior margin oblique, concave, extremity widely rounded; summit of umbo moderately elevated, 

slightly retuse; cardinal area wide, with diverging grooves; 

series of teeth slightly sinuous anteriorly; teeth numerous; at 

the posterior extremity the series suddenly becomes dilated and 

the teeth interrupted or tubercular; inner margin crenate, crenae 

profound, and remote posteriorly. Length, 4 inches; height, 

rather more than 1% inches.

Locality: James River below City Point, Petersburg, Mr. 

Tuomey, Ware River, Gloucester County, Va., Mr. Ruffin— 

Conrad, 1844.
PART 1. PELECYPODA 23

This species strikingly illustrates the characteristic 

of the section—the disintegration of the distal teeth. 

The shell is larger than Granoarca virginiae (Wagner), 

the beaks are not so high and less tumid, the posterior 

margin is less produced, and the ribs are more numerous. The byssal gape, though narrow, is distinct.

Mansfield has indicated the essential resemblance of 

Grranoarca propatula.to the much smaller G. campyla 

Dall, an abundant and diagnostic species of Floridian Pliocene. In Florida Gr. propatula is reported 

only from the Cancellaria zone, the time equivalent of 

the upper beds of the Yorktown formation.

"Distribution: Virginia. Miocene, Yorktown formation, Petersburg, Dinwiddie County (Tuomey) ; below City Point on the 

James River, Prince George County (Tuomey) ; Ware River, 

Gloucester County (Ruffin).

Outside distribution: Miocene, Duplin marl, Darlington, S. C. 

Choctawhatchee formation, Cancellaria zone in Leon County, Fla.

Genus ANADARA Gray

1847. Anadara Gray, Zool. Soc. London Proc., pt. 15, p. 198.

1925. Diluvarca Woodring, Carnegie Inst. Washington Pub. 366, 

p. 40. Suppressed in favor of Anadara by Woodring, 

Carnegie Inst. Washington Pub. 385, p. 18, 1928.

Type by monotypy: Area antiquata Linnaeus. Habitat not determined.

Anadara is a moderately heavy, transversely elongate 

shell with a rather wide range in size. The outline 

and the sculpture are more regular than in Barbatia. 

The byssal gape is much less pronounced and does not 

warp the shell. The beaks are full, and the cardinal 

area is relatively high 'and scarred with concentric 

chevronlike ligament grooves diverging beneath the 

tips of the umbones. The dental series is not broken 

medially, as it is in the adult Barbatia, but the distal 

teeth are larger than the medial, more oblique, and less 

closely spaced. In the larger shells the muscle scars 

are prominent and the inner margins deeply fluted.

The group includes a great number of our Tertiary 

and Recent east coast and Gulf species.

Anadara lienosa (Say) Mansfield 

Plate 2, figures 4, 7

1832. Area lienosa Say, American conchology, pi. 36, fig. 1, and

descriptive text. 

1856. Area lienosa Say. Tuomey and Holmes, Pleiocene fossils

of South Carolina, p. 40, pi. 15, figs. 2, 3. 

1858. Area lienosa Say (part). 'Holmes, Post-Pleiocene fossils

of South Carolina, p. 20. 

1858. Area, lienosa Say. Emmons, North Carolina Geol. Survey

Rept., p. 284, fig. 204.

1863. Scapharca lienosa Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 579.

1864. Scapharca lienosa (Say) Conrad. Meek, Checklist of the

invertebrate fossils of North America, Miocene; Snaithsonian Misc. Coll., No. 183, p. 6. 

1887. Area lienosa Say. Heilprin, Wagner Free' Inst. Sci.

Trans., vol. I, p. 97. 

1898. Scapharca (Scapharca) lienosa Say. Dall, idem, vol. 3,

pt. 4, p. 636.

1916. Area lienosa Say. Sheldon, Palaeontographica Americana, 

vol. I, No. I, p. 35 (part), pi. 7, figs. 26-28; ? pi. 8, 

figs. 1, 2.

1932. Area (Anadara) lienosa Say (part). Mansfield, Florida 

Geol. Survey Bull. 8, p. 50, pi. 3, fig. 8.

Shell rather thin, transversely oblong; ribs about 40, somewhat flattened and much broader than the intervening spaces, 

which are very narrow, and with a longitudinal impressed line, 

particularly on those of the posterior margin, Which are almost 

bifid; and with numerous slightly elevated transverse lines, 

which being divided by the longitudinal striae appear granulated ; beak but little prominent, and nearly opposite to the 

posterior [anterior] third of the length of the hinge margin; 

area narrow and elongated; hinge margin rectilinear, angulated 

at each extremity; teeth numerous, small; posterior [anterior] 

margin obliquely rounded inward, no part of it extending farther backward than the angle; anterior [posterior] margin 

obliquely truncate; inner margin crenate.

A fossil shell from the same locality as the preceding [the 

Santee River, below the confluence of the Congaree and 

Wateree Rivers] and also sent to me by Mr. Elliott.—Say, 1832.

This species has always been rather rare and has been confounded with its undoubted descendant, the Area floridana of 

Conrad, found living in Florida waters. Nevertheless, the 

recent and the fossil shells are readily distinguished on 

comparison. * * * In A. lienosa there are about 40 ribs in a 

specimen 108 millimeters long; these ribs are deeply grooved 

down the center, and the ridges on either side of the grooves 

are likewise longitudinally grooved with one or two incised lines. 

The interspaces between the ribs are narrower than the ribs; 

the beaks are less anterior than in A. secticostata. [= A. 

floridana Conrad]. In the latter the ribs are much narrower than 

their interspaces, fiat-topped, and distally for a little more than 

half their length in the adult the top of the rib has a broad, 

shallow channel. In no case are there any subsidiary grooves. 

Minute concentric ridges are quite obvious in both species, 

but the fossil has the ridges more generally and conspicuously 

beaded. In other respects the shells are extremely similar.— 

Dall, 1898.

Within the area under discussion there is no species 

with which this rare but very conspicuous form is 

readily confusable.

Anadara lienosa is essentially warm-temperate or 

subtropical in its distribution. The records from the 

cooler faunas of the Yorktown formation are fragmentary. This, in itself, is evidence against the inclusion 

in the synonomy of Area protracta, described by the 

Rogers brothers from Prince George County, Va. In 

Florida, Mansfield reports Alienosa from several localities in both the Ecphora and the Cancellaria zones of 

the Choctowhatchee. Related species include Area 

(Scapharca) Jienekeni from the Dominican Republic 

and the Machapoorie horizon in Trinidad and Barbatia 

(Diluvarca) halidonta oresta Woodring from the Bowden of Jamaica. The middle Miocene West Indian 

forms recall not only lienosa of the upper Miocene and 

Pliocene distribution but also the abundant and widely 

distributed group which includes hypomela (Dall) of 

the Chipola and dodona (Dall) of the Oak Grove.

Distribution: North Carolina: Miocene, Duplin marl, 1 mile 

south of Clinton, Sampson County; Natural Well, 1% miles north 

of Magnolia, Duplin County; 4 miles northeast of Fairmont, Robe-
24 MOLLTJSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

son County. Pliocene, Waccamaw formation, Neills Eddy Landing, 3 miles north of Cronly, Columbus County; Wilmington, 

New Hanover County.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Duplin marl, Brunswick River bed, Brunswick, Glynn County, Ga. Pliocene, Waccamaw formation. 

Nixons, Todds Ferry, and Tillys Lake, Horry County, S. C. 

Caloosahatchee marl. Caloosahatchee River, Shell Creek, and 

Alligator Creek, Fla. Pleistocene, Simmons Bluff, Savannah

River, S. C.

i

Anadara protracta (Rogers and Rogers) Gardner

Plate 2, figure 5; plate 3, figure 3

1837. Area protracta W. B. and H. D. Rogers, Am. Philos. Soc.

Trans., n. ser., vol. 5, p. 332. 

1839. Area protracta W. B. and H. D. Rogers, idem., vol. 6, pi.

26, fig. 5. 

1845. Area (Anomalocardia [in plate description only]) protracta Rogers. Conrad, Fossils of the medial Tertiary

of the United States, p. 58, pi. 30, fig. 5. 

1898. Area protracta Rogers. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt 4, p. 627. 

1916. Area lienosa Say (part). Sheldon, Palaeontographica

Americana, vol. 1, no. 1, p. 35, pi. 8, figs. 1, 2.

Shell rather thick, very oblong transversely; ribs about 40, not 

very prominent, hardly wider than the intercostal spaces, and 

longitudinally furrowed by three narrow grooves, the central 

one much the widest; a very indistinct granulation of the 

ribs, arising from the numerous minute transverse line's of 

growth crossing the longitudinal ridges of the ribs; beaks prominent and distant, opposite a point less than .one-third the 

length of the hinge margin from the posterior extremity; area 

wide, with numerous distinct undulated grooves, parallel to the 

hinge margin; hinge margin rectilinear, with numerous minute 

straight teeth, those in the anterior half directed a little 

obliquely toward the anterior margin; posterior margin 

rounded slightly outward, extending a little farther backward 

than the angle; anterior margin much elongated, extending in 

an oval curve far in advance of the end of the hinge; basal 

margin contracted opposite the middle of the hinge, and deeply 

crenate. Length, 3% inches.

Locality, Shell banks, Prince George County, [Va.].—Rogers 

and Rogers, 1837.

In the orientation of the shell, the anterior and posterior margins have been reversed. This species is undoubtedly very close to Anadara lienosa (Say). The 

two may be identical but as the type has not been 

available for consultation it does not seem wise to 

unite them. A. protracta has apparently a greater 

relative width than the normal A. lienosa of Say, with 

a more marked contraction of the basal margin 

and a wider cardinal area. Furthermore the known 

distribution of A. lienosa does not include a fauna of 

so cool water as that indicated by the type locality of 

protracta.

Distribution: The species is not represented in the material 

under discussion nor in any of the collections to which access 

has been gained.

Anadara callicestosa (Dall) Mansfield 

Plate 3, figures 2, 6

1898. Scapharca (Scapharca) callicestosa Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 4, p. 638, pi. 34, figs. 17, 18.

1916. Area callicestosa Dall. Sheldon, Palaeontographica 

Americana, vol. 1, No. 1, p. 43, pi. 10, figs. 3-5.

1932. fArca (Anadara) callicestosa (Dall). Mansfield, Florida 

Geol. Survey Bull. 8, p. 49, pi. 5, figs. 7, 8.

S.hell of moderate size, rather thin, rhbmboidal, with small, 

prominent, mediosulcate, prosocoelous beaks situated at about 

the anterior third of its length; left valve with about 37 

squarish subequal radial ribs, separated by narrower channeled 

interspaces; on the tops of these ribs ajre 4 longitudinal threads, 

the inner pair larger and more prominent but separated by a 

somewhat deeper sulcus than those external to the inner 

threads; concentric sculpture of fine, close, rounded, slightly 

elevated threads, which overrun the whole shell, ribs, and 

interspaces, and at short intervals, at the intersection with the 

inner pair of rib threads they become minutely nodulous, while 

the reticulations have a punctate appearance, giving a surface 

somewhat like fine lace and peculiar, as far as observed, to this 

species; cardinal area short, rather narrow, with sharply elevated boundaries and a single incised set of grooves forming a 

lozenge-shaped figure anteriorly; hinge line short, teeth in two 

adjacent series, anterior with 15, posterior with 26 or 27 teeth set 

vertically, a little oblique at the distal ends of the series; each 

individual tooth more or less grooved or striate in the direction 

of motion, as in some recent species; anterior end of shell produced, rounded; posterior end subtruncate, base slightly arched; 

inner margin of the valves with rather long, deep flutings, 

corresponding to the external ribs. Longitude 32, altitude 27, 

diameter 20 millimeters (twice the diameter of the single valve).

A single valve of this very elegant species was obtained by 

Mr. Burns. Its sculpture differentiates it from all our other 

Tertiary species. Area callipJeura Conrad, in which the ribs 

have a minute nodular sculpture, has the radial threading 

predominant, while in this species the concentric threads overrun all the rest. The two species aref entirely distinct 

otherwise—Dall, 1898.

Holotype: U. S. Nat. Mus. 146264.

Type locality: U. S. G. S. station 2833. Upper bed 

(Miocene) at Gaskins Wharf, on the Nansemond River, 

16 miles below Suffolk, Va., F. Burns.

The specimens from the Ecphora and Cancellaria 

zones of the Choctawhatchee referred by Mansfield to 

A. callicestosa are not typical and may, as Mansfield 

suggests, prove to be subspecifically distinct. The 

specimen figured by Mansfield seems closer to magnoliana than to the holotype of callicestosa^ but it is 

relatively higher than the North Carolina species and 

has developed a much wider cardinal area. With so 

little material, it is difficult to discriminate between 

individual, age, and taxonomic differences.

Distribution : Virginia: Miocene, Yorktown formation, Gaskins 

Wharf, Nansemond County. The type is still unique.

Anadara callicestosa wilsorii Gardner, n. subsp.

Plate 3, figures 8, 9, 12

The subspecies is based on the following criteria:" 

Anadara callicestosa subsp. wifeoni is a relatively higher 

form than A. catticestO'S® (Dall), the base line is more 

rounded, the anterior margin less produced, the posterior margin more produced and more obliquely truncated, the umbones are more convex, the cardinal area 

is higher and marked with 2 or 3 irregular groovings
PART 1. PELECYPODA 25

instead of a single half-diamond groove; the hinge 

characters are practically identical; the ribs, however, 

number 33 instead of 37 as in the type of the species, 

and the intercostal areas approximately equal the 

costae in width; the general type of sculpture of the 

individual costae is the same, but the nodular effect is 

somewhat lost by the wider separation of the ribs.

Dimensions of holotype: Height 30.6 millimeters, 

width 34.3 millimeters, convexity of single valve, 12.5 

millimeters.

Holotype: U. S. Nat. Mus. 325488.

Type locality: Frank Wilson's) marl pit near 

Magnolia, N. C.

Further material may show these variations to be 

merely individual instead of subspecific, but in the absence of a connecting series it seems better to keep 

the forms separate.

Distribution: North Carolina: Miocene, Duplin marl. The 

subspecies is described from a single left valve from the marl 

pit of Frank Wilson near Magnolia, Duplin County.

Anadara magnoliana Gardner, n. sp.

Plate 3, figures 1, 4, 5, 7

Shell thin, inflated, inequilateral, roughly rhomboidal, gently rounded anteriorly, slightly produced 

and obliquely truncated posteriorly. Umboues prosocoelous, fairly prominent, placed near the anterior 

third of the hinge line. Cardinal area narrow, sharply 

delimited, sculptured with 2 diamond-shaped grooves. 

Length of hinge approximately three-fifths of the total 

length of the shell. Teeth very short and close-set 

beneath the beaks, becoming larger and less crowded 

distally; anterior denticles 17, slightly concave forward ; posterior denticles 28; in the type the proximal 

10 are perpendicular to the hinge, the 10 behind them 

with a slight backward slant, the final 8 slanting a little forward; both anterior and posterior distal teeth, 

grooved on each side. Radial sculpture of 37 costae, 

which over the greater part of the disk are strongly 

arched, becoming narrower and less prominent toward 

the anterior lateral margin and on the posterior portion of the shell broadening and flattening upon the 

summits; intercostal areas subequal to the costal and 

to one another, squarely channeled over the mesial 

and posterior parts of the shell, though less angular 

anteriorly; each individual costal sculptured with 4 

longitudinal riblets, of which the second and third are 

the most elevated; riblets strongest on the anterior 

part of the disk, less prominent near the anterior 

lateral margin, and posteriorly becoming almost or 

altogether obsolete; characteristic effect of the sculpture due largely to the undulation of the crests of the 

medial and anterior costae; riblets strongest upon the 

crests of the waves, evanescent in their troughs, thus 

lending a subnodular aspect to the radial ornamentation; entire surface of shell covered with crowded incrementals; interior flutings corresponding to exterior 

costae.

Dimensions of holotype: Height 34.3 millimeters, 

width 46.7 millimeters, convexity of single valve, 12.0 

millimeters.

Holotype: U. S. Nat. Mus. 325486.

Type locality: Natural Well, Duplin County, N. C.

The peculiar lacelike pattern of the surface sculpture, which was noted in the original description of A 

callicestosa (Dall), is reproduced in magnolia/no,. The 

shells differ widely, however, in outline and in the 

characters of the cardinal area and hinge teeth. The 

species has not been observed, except from the marls 

in the vicinity of Magnolia, Duplin County, N. C.

The form has been described from a single valve— 

the right. Another right valve, from near the same 

locality, exhibits a shorter and relatively higher outline ; the ribs are more closely crenulated than those of 

the type and, on the disk, exhibit 3 instead of 4 riblets; 

the anterior and posterior costae, however, do not differ 

in sculpture detail from those of the type.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, and 1% miles north of Magnolia, Duplin County.

Anadara carolinensis (Wagner) Gardner

Plate 2, figure 6

1848. Area carolinensis W. Wagner. Bronn, Handbuch Geschichte Natur, Index palaeontologicus, pt. 1, p. 93 

(nomen nudum).

1849. Area carolinensis W. Wagner. Bronn, idem, pt. 2, p. 281 

(nomen nudum). Not Barbatia (Plagiarca) carolinensis Conrad, 1875.

1897. Area carolinensis Wagner, Wagner Free Inst. Sci. Trans., 

vol. 5, p. 9, pi. 1, fig. 4. Explanatory text by Dall.

1898. Scapharca (Scapharca) carolinensis Wagner. Dall, idem,

vol. 3, pt. 4, p. 639, pi. 33, fig. 11. 

1916. Area carolinensis Wagner. Sheldon, Palaeontographica

Americana, p. 42, pi. 10, figs. 1, 2.

Shell laijge, solid, squarish, moderately inflated, with subcentral, prosocoelous, rather elevated beaks; left valve with 

about 30 ribs, with subequal interspaces, the anterior ribs 

squarish, with a shallow median sulcus near the margin, and 

irregular concentric ripples; the ribs of the middle of the valve 

not sulcate, with less rippling, more closely adjacent, the interspaces very squarely channeled; the posterior ribs smaller, 

rounded, and more closely set; cardinal area short, rather wide, 

smooth or longitudinally striate, with 3 concentric lozengeshaped groovings; hinge line short, solid; the teeth not interrupted, strong, about 45 in all, the anterior more vertical, the 

middle teeth inclining towards the middle line of the area, 

the posterior teeth distally more oblique and longer; margins of 

the shell strongly fluted. Longitude 56, altitude 55, diameter 

43 millimeters (type specimen).

As this species seems never to have been described, the references in Bronn being merely to Wagner's unpublished plates, I 

have given a diagnosis from Professor Wagner's original type 

specimen and refigured the interior of the left valve. The shell 

is r-ein'arkable for its squarish form, which is rather distantly 

approached by some specimens of A. idonea. , It is singular that 

in all the years which have elapsed since this shell was collected 

and figured by Professor Wagner no one has recognized or 

described it.—Dall, 1898.
26 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

The species differs from Area idonea Conrad in the 

more equidimensional outline and the lower cardinal 

area. The type locality is pot known, but Dall (1897) 

reports that "a valve in the collection of the United 

States National Museum was obtained from the upper 

Miocene of Duplin County, N. C."

Distribution: Virginia: Miocene, St. Marys formation?, 

Nomini Cliffs, Westmoreland County. St. Marys formation, 

Union Mill, 2% miles south of Farnham, Richmond County. 

Very rare at both localities.

North Carolina: Miocene, Duplin marl, 4 miles south of Clinton, Sampson County; Natural Well and 1% miles north of 

Magnolia, Duplin County.

Section CUNEARCA Dall

1898. Cunearca Dall, Wagner.Free Inst. Sci. Trans., vol. 3, pt. 4, 

p. 618.

Type by monotypy: Area incongrua Say. Recent from Hatteras to Aspinwall and the western Gulf of Mexico.

The section Cunearca is characterized by the short, 

high outline, the inequality of the valves, the left the 

larger of the two, the discrepancy in their sculpture, 

and the full, erect umbones topping a high, sufosymmetrical cardinal area.

Anadara (Cunearca) scalaris (Conrad) Dall

Plate 2, figure 2

1844. Area, scalaris Conrad, Acad. Nat. Sci. Philadelphia Proc., 

vol. I, p. 324.

1845. Area scalaris Conrad, Fossils of the medial Tertiary of

the United States, p. 59, pi. 31, fig. 1.. 

1856. Area scalaris Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 43, pi. 16, figs. 1, 2. 

1858. Area scalaris Conrad. Emmons, North Carolina Geol.

Survey Rept, p. 284.

1863. Scapharea scalaris Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, p. 580. (Name only.)

1864. Scapharca scalaris Conrad. Meek, Checklist of invertebrate fossils of North America ; Smithsonian Misc. Coll. 

No. 183, p. 6.

1898. Scapharca (Cunearca) scalaris Conrad. Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 634.

1916. Area scalaris Conrad. Sheldon, Palaeontographica Americana, vol. 1, No. 1, p. 57, pi. 13, figs. 10,11.

1932. Area (Cwiearca) scalaris Conrad. Mansfield, Florida 

Geol. Survey Bull. 8, p. 53, pi. 7, fig. 4.

' Obliquely rhomboidal, elevated, ventricose, ribs about 23, 

broad, square, prominent, profoundly and robustly crenate, 

wider than the interstices, 7 on the posterior slope, prominent; 

posterior slope flattened; umbonial slope angulated; summit 

elevated, narrowed; anterior margin obliquely truncated; anterior basal margin obliquely sub truncated; posterior extremity 

subangulated; beaks remote; area with transverse slightly impressed lines; cardinal teeth irregular, oblique toward the extremities of the hinge line; within with furrows corresponding 

to the ribs; margin profoundly crenate. Length 2 inches, 

height iy2 inches.

Locality: Petersburg, Va., Mr. Tuomey. Allied to A. incongrua 

Say. The description applies to the left valve only, as the 

opposite one has not yet been found—Conrad, 1844.

Tuomey and Holmes found it necessary to give the 

criteria for discriminating this species from Area transversa Say, a species with which it has nothing in common but the subgeneric characters. The real affinities 

are with Anadara scalarina (Heilprin) of the Pliocene 

and A. incongrua Say of the Recent fauna.

Anadara scalarina is larger and heavier but strikingly similar in general aspect, particularly as regards 

the left valves. The right valve of the Pliocene species 

develops a secondary rib intermediate between the primaries of the disk, and of this there is no trace on the 

earlier scalaris or on the Pleistocene and Recent incongrua—a species much smaller, however, than scalaris 

and lacking the conspicuous inflation of the umbones.

Mansfield reports the species from both the Ecphora 

and the Cancellaria zones of the Choctawhatchee.

Distribution : Virginia : Miocene, Yorktown formation, Petersburg, pinwiddie County. Although Conrad's type was presumably collected at Petersburg, the species has not been reported 

from this or any other Virginia locality since his day.

North Carolina: Miocene, Duplin marl, W. H. Kornegay's 

marl pit near Magnolia, Duplin County. Pliocene, Waccamaw 

formation, Walkers Bluff on the Cape Fear River, Bladen 

County. The species is extremely rare'at both these localities.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. -*

Family GIYCYMERIDAE 

Genus GLYCYMEUIS Da Costa

1778. Glycymeris Da Costa, Historia naturalis testaceorum Britanniae, or The British conchology, p. 168.

Type by subsequent designation (Dall, Wagner Free Inst. 

Sci. Trans.,-vol. 3, pt. 4, p. 607, 1898). Glycymeris orUoularis 

Da Costa=Arco. glycymeris Linnaeus. Recent off the British 

Isles and the coast of Europe.

Shell heavy, equivalve, equilateral or subequilateral, 

suborbicular; the anterior extremity usually the more 

produced and rounded. Beaks almost straight, only 

slightly incurved. Outer surface concentrically or radially striate or sulcate. Ligament amphidetic, multivincular, the ligament furrows arranged in concentric 

rhombs. Hinge margin arcuate, set with two series of 

strong transverse teeth, chevron-shaped medially, the 

distal teeth oblique to horizontal; teeth progressively 

obliterated during growth by the subsidence of the ligament area. Adductor scars distinct, the posterior buttressed. Pallial line simple or very, slightly sinuous. 

Inner margins crenulate in harmony with the outer 

ribbing.

The genus is first recognized in the Cretaceous; it 

culminated in the mid-Tertiary and is represented in 

the Recent fauna by about 80 species, widely distributed 

in the shallower waters of the warm and temperate seas.

Glycymeris laevis (Tuomey and Holmes) Dall

Plate 1, figure 11

1848. Pectunculus virginiae W. Wagner. Bronn, Index paleontologicus, pt. 1, p. 940. 

3849. Pectunculus virginiae W. Wagner. Bronn, idem, pt. 2,

p. 283. 

1856. Pectunculus laevis Tuomey and Holmes, Pleiocene fossils

of South Carolina, p. 50, pi. 17, fig. 5.
PART 1. PELECYPODA 27

1897. Pectunculus mrginiae Wagner. Wagner Free Inst. Sci. 

Trans., vol. 5, p. 11, pi." 3, fig. 5. Explanatory text by 

Ball.

1898. Glycymeris laevi$ Tuomey and Holmes. Ball, idem, vol. 3, 

pt. 4, p. 609.

Somewhat oval, thick, inequilateral, concentrically striate, or 

grooved ; buccal margin rounded ; anal side somewhat produced, 

obliquely truncate; many teeth; lip crenate,

The teeth extend without interruption around the hinge. 

The pallial and muscular impressions are well defined, and in 

young individuals the shell is slightly angular near the umbones. 

Umbones pointed and, closely approximating.

Locality, Waccamaw.—Tuomey and Holmes, 1856.

Wagner's name, though earlier, is not entitled to 

standing, as his figure was never published. The plate 

on which it appears is, according to Dall, 1898, in the 

possession of the Wagner Free Institute of Science in 

Philadelphia.

The species is characterized by the absence of radiating sculpture.

Distribution: Wagner's locality is not known, and the species 

is not represented in any of the later Virginia collections.

Outside distribution: Pliocene: Waccamaw formation, Waccamaw, S. C. (Tuomey and Holmes).

Glycymeris tumulus (Conrad) Dall?

Plate 1, figures 6, 12-15

1845. Pectunculus tumulus Conrad, Fossils of the medial 

Tertiary of the United States, p. 72, pi. 41, fig. 4.

1898. Glycymeris americana (Defranee) (part). Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 609.

Suborbicular, ventricose, surface with numerous radiating 

slight furrows and fine decussated striae; margins rounded, 

umbo and summit profoundly elevated; dorsal margin equally 

and profoundly oblique, beaks distant; cardinal area wide and 

marked with well-defined diverging grooves; cardinal teeth 

large, robust, nearly straight, the series very oblique and 

widely interrupted in the middle by a crenulated rectilinear 

space.

Locality, near Petersburg, Va.—Conrad, 1845.

The collection of further material and the careful 

comparison with Conrad's type by W. C. Mansfield 

seem to justify the rehabilitation of this species, which 

had been lost in the lengthy synonymy of G. americana.

Shell evenly rounded ventrally, cuneate dorsally, decidedly tumid in the umbonal region. Radial 

sculpture absent laterally, obsolete ventrally, consisting 

of about 21 feebly impressed grooves; faint secondary 

striae occasionally discernible on the interareas. 

Growth lines prominent near the ventral margin. 

Cardinal area high, ornamented with broad, shallow 

furrows. Hinge line strongly arched. Hinge teeth in 

two discrete series, 12 or 13 in each; denticles coarse, 

obliquely set, the dorsal surface finely striated horizontally. Muscle scars conspicuous, semielliptical, 

united by a simple pallial line. Marginal flutings 

corresponding in number to the primary lines of the 

exterior surface.

Figured specimen: Height 44.5 millimeters, width

44.7 millimeters, maximum convexity 28.4 millimeters. 

The presence of secondary radial striae recalls 

Glycymeris americana (Defrance). It is separable 

from that species, however, by the cuneate outline of 

the dorsal portion of the shell, the high, tumid 

umbones, and the less prominent radial sculpture. 

The outline of the shell serves also to distinguish it 

from Glycymeris parilis (Conrad), the common 

Maryland representative of the group.

Distribution: Virginia : Miocene, St. Marys, formation, Nomini 

Cliffs, Westmoreland County. The species, is represented in the 

single formation at several localities.

Glycymeris duplinensis Dall

Plate 2, figure 3; plate 5, figure 5

1898. Glycymeris duplinensis Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 4, p. 613, pi. 34, figs. 6, 7.

Shell small, rounded-triangular, solid, moderately convex, 

with pointed, small, low beaks and a flattened lunular area; 

sculpture of strong, distally bifurcated radial ribs, separated 

by slightly narrower channeled interspaces; 9 anterior and 9 

posterior ribs, on the lateral slopes are smaller, while on the 

middle of the shell are about 10 larger ribs; transverse sculpture of regularly spaced, elevated concentric lines overrunning 

the whole shell; cardinal area small and short, with 3 or 4 

concentric angular grooves; teeth small, vertically striated, 

6 or 7 on each side, the line strongly arched and uninterrupted; 

anterior margin straight, base rounded, posterior slightly 

arcuate; basal inner margin with about 10 flutings. Largest 

valve, longitude 9, altitude 10, diameter 6.5 millimeters.

This pretty little species is readily distinguished from any 

of the varieties of G. pectinata by its bifurcated and prettily 

sculptured ribs. It seems to be rather abundant at the 

locality mentioned.—Dall, 1898.

Holotype: U. S. Nat. Mus. 114941.

Type locality: Natural Well, Dupliii County.

Distribution: North Carolina: Miocene, Yorktown formation, 

\ mile north of Castoria and 1 mile east of Lizzie, Greene 

County; 2 miles southwest of Maple Cypress and Rock Land-* 

ing, Craven County. Duplin marl, Natural Well, Duplin 

County. Pliocene, Waccamaw formation, Walkers Bluff, 

Bladen County.

Glycymeris americana (Defrance) Dall

Plate 1, figures 16-21

1826. Pectunculus americanus Defrance, Dictionnaire des

sciences naturelles, vol. 39, p. 225. 

1832. Pectunculus pulvinatus Lamarck. Conrad, Fossil shells

of the Tertiary formations of North America, p. 17,

pi. 2, fig. 2. Not P. pulvinatus Lamarck, 1819. 

1835. Pectunculus lentiformis Conrad, Idem, 2d ed., p. 36,

corrigenda. 

1841. Pectunculus quinquerugatus Conrad, Am. Jour. Sci., 1st

ser., vol. 41, p. 346. 

1845. Pectunculus lentiformis Conrad, Fossils of the medial

Tertiary of the United States, p. 64, pi. 36, fig. 1. 

1845. Pectunculus tricenarius Conrad, idem, p. 63, pi. 35, fig. 1

(immature shell). 

1845. f Pectunculus quinquerugatus Conrad, idem, p. 63, pi. 34,

fig. 3. 

1845. Pectunculus passus Conrad idem, p. 64, pi. 35, fig. 3.
28 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1856. Pectunculus lentiformis Conrad. Tuomey and Holmes,

Pleiocene fossils of South ^arolina, p. 48, pi. 17, fig. 2. 

1856. ? Pectunculus quinquerugatus Conrad. Tuomey and

Holmes, idem, p. 49, pi. 17, fig. 4. 

1858. Pectunculus carolinensis Holmes, Post-Pleiocene fossils of

South Carolina, p. 15, pi. 3, fig. 4. Not P. carolinensis

Conrad, 1841. 

1858. Pectunculus lentiformis Emmons, North Carolina Geol.

Survey Rept., p. 286. 

1886. Pectunculus undatus Linnaeus. Dall, Harvard Coll. Mus.

Comp. Zoology Bull., vol. 12, p. 238. 

1898. Glycymeris americana Defranee (part). Dall Wagner

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 609. ' 

1932. Glycymeris americana (Defranee). Mansfield, Florida

Geol. Survey Bull. 8, p. 39, pi. 2, fig. 7.

P6toncle americain. Petunculus americanus Defrance. 

Coquille suborbiculaire, aplatie et couverte de larges cStes longitudinales peu elevees et finement striees. Longueur plus de 2 

pouces. On la trouve a la Caroline du Nord.—Defrance, 1826.

A very.careful and conscientious scrutiny of a large number 

of specimens has resulted in the above synonymy. G. imssa 

is the normal adult; G. lentiformis, the senile adult; G. tricenaria 

is a half-grown, well-developed form; G. carolmensis Holmes is a 

variety with feeble ribbing, obsolescent at the ends of the shell; 

G. transversa, Tuomey and Holmes (non Deshayes) is founded 

on the internal cast of a rather wide young shell; G. tumulus 

Conrad is founded" on a rather inflated half-grown specmen. The 

only form which may possibly be varietal, but which I am inclined to refer to some pathologic cause, is G. quinquerugata. 

This is almost entirely confined to Duplin County, N. C. Wellmarked specimens have on each dorsal slope, from the beaks 

laterally, 3 to 6 little irregular ripples, which are much more 

conspicuous in the young. These might indicate the presence of 

some parasite in the individual. They are never uniform or 

regular; some specimens have them only on one side, in others 

they are obsolete, and, finally, others do not have them; 

and between the normal americana and the quinquerugata 

without rugae there is absolutely no distinction to be made. 

The recent shell is identical with Miocene specimens and 

reaches fully as large a size.—Dall, 1898.

Pectunculus tumulus Conrad, however, incltided by 

Dall under this species, is undoubtedly distinct.

Of the bivalves occurring within the area under consideration, the only one confusable with G. americana 

is the very rare pennacea (Lamarck). Though resembling each other in the general character of the 

fine radiate sculpture, they are readily separable by 

more basic differences in outline and hinge. G. americana reaches a much greater maximum diameter, the 

valves are normally equilateral, and the umbonal slopes 

are evenly rounded. In the smaller G. pennacea the 

anterior lateral margin is more or less sharply truncated and the anterior umbonal slopes are more or 

less angular. The cardinal area of pennacea is wider 

than in an americana of the same size, the hinge is 

thicker, the teeth are fewer and heavier and set in a 

higher curve.

The young of americvma are pretty little forms, 

subcircular in outline, except for the hinge truncation, 

with a dainty, minutely granular, radiate sculpture.

In Florida Mansfield found that the distribution of 

the species was restricted to the Ecphora and Canzones of the Choctawhatchee formation, the 

supposed time equivalents of zones 1 and 2 of the 

Yorktown.

Distribution: Virginia: Miocene, Yorktown formation. 

Yorktown, York County; Petersburg, Dinwiddie County; 1% 

miles northeast of Smithfield and % mile northeast of Smithfield, Isle of Wight County; V2 to % mile above the lower Seaboard Railway bridge, Southampton County; *4 mile north of 

Chuckatuck, l1^ miles north of Suffolk, 1 mile northeast of 

Suffolk, % mile below the Suffolk waterworks dam, Suffolk, 

and the drainage ditch of the Norfolk & Western Railway just 

east of Jericho ditch, Nansemond County.

North Carolina: Miocene, Yorktown formation. Halifax, 

Halifax County; 2% miles northwest of Williamston and \ 

mile northwest of Williamston, Martin County; % mile above 

Bells Bridge and % mile below Bells Bridge, Edgecombe 

County; 2% miles north of Standard, 3 miles south of Farmville, Pinelog Branch, 8 to 9 miles west of Greenville, 3 miles 

west of Greenville, 2 miles west of Greenville, 1% miles west 

of Greenville, 8 to 9 miles south of Greenville, and 9 to 10 < 

miles south of Greenville, Pitt County; 2% miles northwest of 

Chocowinity and 2 miles northwest of Chocowinity, Beaufort 

County; \ mile west of Wilson and 3 miles east-southeast of 

Wilson, Wilson County; % mile east of Lizzie, 2 miles northeast of Lizzie, 4 miles east of Lizzie, Greene County; 1% 

miles below Tar Ferry and 3 to 4 miles below Tar Ferry, and 

Dogwood Landing, Hertford County; Colerain Landing, Bertie 

County; Rock Landing, Craven County. Duplin marl, Natural 

Well and marl pits in the immediate vicinity, Duplin County; 

1 mile west of Lumberton, Lumberton, 2 miles below Lumberton, 

4 to 5 miles below Lumberton, and Ashpole, Robeson County; 

4 miles south of Clarkton, Bladen County. Pliocene, Waccamaw formation, Walkers Bluff, Bladen County; Lake Waccamaw, Cronly, and Neills Eddy Landing near Cronly, Columbus 

County; Wiimington and the city rock quarry near Wilmington, New Hanover County.

Outside distribution: Miocene, Duplin marl, Darlington, 

Darlington County, S. C. Pliocene, Waccam'aw formation, 

Nixons, Tillys Lake, and Todds Ferry, Horry County, S. C.; 

Waccamaw, S. C., Choctawhatchee formation, northern Florida. 

Caloosahatchee marl, Caloosahatchee River, Fla. Pleistocene, 

Simmons Bluff, S. C. Recent, Hatteras to Santa Marta, Brazil, 

in 15 to 63 fathoms.

Superfamily MYTILACEA

The Mytilacea were included by Dall under a group 

which he called the dysodonta—the imperfectly toothed 

forms—a term first used by Neumayr but in a more 

.comprehensive sense. In the early generic separations 

the teeth were perhaps considered too casual a character, an$ the form and surface sculpture too heavily 

weighted. However, Dall recognized /the dentition to 

be of major importance in determining the relative 

position of the dysodonts and considered the dysodont 

hinge to be essentially a taxodont hinge modified by 

umbonal torsion. The full significance of the mytiloid 

hinge in establishing the mode of development of the 

lamellibranch dentition was first perceived by 

Bernard,34 who detected in it the key to the problem

3* Bernard, Felix, Troisieme note sur le development et la morphologie de la coquille chez les lamellibranches (anisomyaires) : Soc. g6ol. 

France Bull., s6r. 3, vol. 24, pp. 412-449, 1896; Recherches ontogfiniques 

et morphologiques sur la coquille des lamellibranches: Annales scl. nat. 

zool. et pal., ser. 8, yol. 8, pp. 1-208, pis. 1-12, 1898.
PART 1. PELECYPODA 29

of evolution of the bivalve hinge by reason of the lack 

of acceleration in its development and the ease with 

which the stages of growth may be separated one from 

the other. Bernard made no attempt to incorporate 

his results in the current systematic classifications, but 

Jukes-Browne,35 impressed by their importance, "reconsidered the generic values of the characters presented 

by the shells of the Mytilidae" and realined the 

genera. In his revision the position of the umbones 

and the surface sculpture were treated as characters of 

secondary importance, whereas the dentition, which 

commonly reflects an important embryonic character, 

the position of the ligament, and the number and character of the muscle impressions were given primary 

consideration. The resulting classification is based on 

wider study than the earlier taxonomic arrangements 

and has been followed in the present paper.

Family MYTILIDAE 

Genus BRACHIDONTES Swainson

1840. Brachidontes Swainson, Treatise on malacology, p. 384. 

1905. Brachyodontes, Jukes-Browne, Malacol. Soc. London Proc., 

vol. 6, p. 222.

Type by monotypy: Modiola sulcata Lamarck. Recent in the 

Indian Ocean.

BracMdontes has been commonly considered a subgenus or section of Modiolus signalized by a radially 

sulcate sculpture. It was given generic status by 

Jukes-Browne because of the crenulate posterior 

margin, an important embryonic character retained in 

the adults of this group. Another constant feature of 

the genus as defined and restricted by Jukes-Browne is 

the musculature, indicated by a small but distinct 

anterior adductor scar and by a much larger posterior 

adductor to which is united the scars of the median and 

posterior byssal retractors. The hinge line is for the 

most part straight and its union with the posterior 

lateral margin angular. The ligament is short and 

marginal or submarginal. The position of the 

umbones varies with the development of the anterior 

portion of the shell, and although the external surface 

is characteristically sculptured with a fine bifurcate 

ribbing, a few species are wrinkled or smooth.

The form otf Swainson's name has bothered the 

classical scholars who have followed him. Brachydontes 

has been commonly used in place of Braohidontes, and 

Jukes-Browne has further purified the barbarism by 

converting it to Brachyodontes. However, article 19 

of the International Rules of Zoological Nomenclature, 

Monaco, 1913, provides that "the original orthography 

of a name is to be preserved unless an error of 

transcription, a lapsus calami, or a typographical error 

is evident."

85 Jukes-Browne, A. J., A review of the genera of the family Mytilidae: 

Malacol. Soc. London Proc., vol. 6, pp. 211-224,1905. 

401033—43———3

Subgenus ISCHADIUM Jukes-Browne

1905. Ischadium Jukes-Browne, Malacol. Soc. London Proc., 

vol. 6, p. 223.

Type by original designation: Ischadium hamatum (Say). 

Miocene to Pleistocene along the eastern seaboard; Recent from 

Rhode Island to the West Indies and Texas.

Shell oblong or pyriform in outline, sculptured all over with 

strong raised divaricating ribs. Umbones slightly divergent; 

anterior riblets well marked and corresponding with a variable 

number of dysodont teeth. Ligament long, without crenulations behind it. Anterior adductor scar absent, and anterior 

byssal scar small. Posterior byssal scar large and broadly 

united to that of the posterior adductor. Type, /. hamatum 

(Say).—Jukes-Browne, 1905.

Brachidontes (Ischadium) recurvus (Rafinesque) Gardner

Plate 1, figures 7, 8

1820. Mytilus recurvus Rafinesque, Monographic des coquilles

bivalves fluviatiles de la riviere Ohio, Annales gen. 

. sci. phys. Bruxelles, vol. 5, p. 320. 

1822. Hytilus hamatus Say, Acad. Nat. Sci. Philadelphia Jour.,

1st ser., vol. 2, p. 265. Binney's reprint of Say, pp. 91,

204, pi. 1. 

1832. Mytilus hamatus Say, American conchology, pi. 50, figs. 1,

2, and unpaginated test. 

1837. Modiola carolinensis Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 243, pi. 20, fig. 6. 

1869. Brachydontes hamatus Perkins, Boston Soc. Nat. History

Proc., vol. 13, p. 156. 

1898. Mytilus (Hormomya) hamatus Say. Dall, Wagner Free

Lost. Sci. Trans., vol. 3, pt. 4, p. 789. 

1906. Mytilus hamatus Say. Clark, Maryland Geol. Survey,

Pliocene and Pleistocene, p. 203, pi. 60, figs. 5, 6.

Moule recourb£e. Test obovale, cunelforme, recourb§, 9, 

stries longitudinales de trois longueurs; epiderme noiratre; 

nacre-violette; bees obliques, a un angle decurrent, de chaque 

cote; bord inferieur et interieur stri£, crenele; largeur 7-12;- 

diametre 5-12 de la longueur, longueur 1 a 2 pouces. Elle ge 

trouve dans le Mississippi pres de la Nouvelle-Orleans. Les 

stries sont souvent bifides. Partie batllante oblongue, laterale.— 

Rafinesque, 1820.

Shell very much contracted and incurved at the base, which 

is acute; valves striated on every part of the exterior with 

longitudinal, elevated lines, which are bifid and sometimes trifid 

toward the tip; color dark fuscous; within dark purpurescent, 

with a whitish margin.

Length 1% inches, breadth nearly % inch.

Inhabits the Gulf of Mexico.

Cabinet of the Academy and Philadelphia Museum.

A common species in the Gulf of Mexico, and is frequently 

carried to market at New Orleans attached to the common 

oyster.—Say, 1822.

Undoubtedly the species can be definitely determined 

from Eafinesque's description published in the obscure 

monograph on the bivalves of the Ohio River, and for 

that reason it should receive his name, which antedates 

the commonly accepted Mytilus hamatus of Say by 2 

years.

Distribution: Virginia: Miocene, Yorktown formation, lorntown and Bellefield, York County.

North Carolina: Pliocene, Waccamaw formation, Walkers 

Bluff, Bladen County; Neills Eddy Landing, Columbus County.
30 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Outside distribution: Pliocene, Caloosahatchee marl, Galoosahatchee River, Fla. Pleistocene, Sankaty Head, Mass.; Wailes 

Bluff, near Cornfield Harbor, St. Marys County, Md. Recent, 

Rhode Island to Costa Rica in less than 50 fathoms.

Genus CRENELLA Brown

1827. Crenella Brown, Illustrations of the conchology of Great

Britain and Ireland, pi. 31, figs. 12-14. 

1844. Crenella Brown, Illustrations of the Recent conchology

of Great Britain and Ireland, 2d ed., p. 75, pi. 23, figs.

12-14.

Type by monotypy: Mytilus decussatus Montagu. Recent 

off the coast of Greenland and in North Atlantic waters.

Crenella precursor Gardner, n. sp.

Plate 3, figures 14-16

Shell both large and heavy for the genus; evenly 

ovate, moderately inflated. Umbones acute, prosogyrate, incurved. Sculpture of about 70 low, flat, radiating lirations, rarely dichotomous toward the ventral 

margin; interareas slightly narrower; increirientals 

mostly microscopic, 3 or 4 of them exaggerated. Inner 

margin obscurely crenulated. Interior lined with a calcareous layer continued to the pallial line. Hinge noncrenulate. Ligament furrow shallow, extending from 

beneath the umbones about one-fourth the distance 

down the posterior margin. Anterior adductor muscle 

impression elongated; posterior semioval. Pallial line 

faintly sinuous.

Dimensions of holotype: Height 7.6 millimeters, 

width 6.4 millimeters, convexity 2.1 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325498.

Type locality: 1 mile northeast of Suffolk, Nansemond County, Va.

Crenella precursor has little but the generic characters in common with the minute Crenellas of the C. 

divaricata type. Its nearest relative and its probable 

descendant is the Recent C. glandula Totten of the 

North Atlantic coast. It is separated from this by the 

more regularly ovate outline, the more acute, prosogyrate beaks, the fewer, broader, flatter, less divaricate 

radials. The single valve from which the description 

has been made is probably senile. Younger individuals would doubtless show a crenulated hinge and a 

more strongly crenulated margin.

Distribution: Virginia: Miocene, Yorktown formation, \ mile 

northeast of Suffolk, Nansemond County.

Superfamily PECTINACEA Reeve 

Family PECTINIDAE Lamarck

Genus PECTEN Mtiller 

1776. Peoten Mu'ller, Zoologiae danicae prodromus, p. 248.

Type by subsequent designation (Schmidt, C. F., Versuch tiber 

die beste Einricht., etc., pp. 67,177, Gotha, 1818) : Ostrea maxima, 

Linnaeus. Recent in the north European seas.

Shell approximately equilateral, inequivalve, auriculate; right valve, as a rule, the more convex, not adherent but attached by a byssus. Hinge line straight, the

cardinal margin of the right auricles curved downward. Resilium central, internal, triangular; interlocking grooves and ridges diverging from the apex 

of the resilial pit. Pallial line simple. Monomyarian. 

Adductor impression rounded, posterior.

The earliest Pecten known is from the Cretaceous. 

The Recent species exceed 200 in number, and their distribution is world-wide.

Subgenus EUVOLA Ball

1898. Euvola Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, 

p. 694.

Type by original designation: Pecten zicsac Linnaeus. 

Southern Florida and the West Indies.

Euvola is characterized by the high inflation of the 

right valve, the flat or slightly concave left valve, a 

radial sculpture that is less strong and less regular than 

that of Pecten s. s., and the development of a single 

pair of cardinal crurae.

Pecten (Euvola) raveneli Dall

Plate 4, figure 4

1898. Pecten (Pecten) raveneli Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 4, p. 721, pi. 29, fig. 10. 

1934. Pecten raveneU Dall. Johnson, Boston Soc. Nat. History

Proc., vol. 40, No. 1, p. 23 (synonymy in part excluded). 

1936 (March). Pecten (Pecten) raveneli Dall. Tucker, Am.

Midland Naturalist, vol. 17, No. 2, p. 483, pi. 2, fig. 4. 

1936 (April). Pecten (Euvola) raveneli Dall. Mansfield, Jour.

Paleontology, vol. 10, pp. 174,182,184,185.

Shell much of the size and form of P. medius Lamarck but 

with 21 or 22 strong ribs; dichotomous in the right valve but 

rounded and simple in the left, with 3 or 4 finer threads on the 

submargins; interspaces of the right valve smaller than the 

squarish ribs, on the left subequal; right valve with subequal 

ears, each with 3 or 4 strong, rounded riblets; notch shallow; 

ears of the left valve concave, 2-ribbed, with less pronounced 

sculpture; surface of both valves covered with close-set, concentric, elevated lines; interior fluted, crura moderately developed. Altitude 42, latitude 47, diameter 13 millimeters.

This neat little species differs from P. medius in its coarser 

sculpture, and from the young of P. hemicyclicus by its more 

numerous ribs and details of surface.—Dall, 1898.

Holotype, a right valve: U. S. Nat. Mus. 107750.

Type locality: Pliocene of the Caloosahatchee River, 

Fla.

The right valve of Pecten raveneli Dall is very much 

inflated, the left valve slightly concave. The species is 

represented in the area under consideration by a single 

adult right valve and a valve of a young form. The 

dichotomous ribs, the small, squarish auricles, and the 

delicate concentric sculpturing are, however, sufficient 

to characterize it.

Distribution: North Carolina: Miocene, Duplln marl, Fairmont, Robeson County. The species is represented by a single 

valve.

Outside distribution: Pliocene, Caloosahatchee marl, Caloosahatchee River, Fla. (?) Recent, dredged off Cape Fear with 

other fossil species in 15 fathoms. Johnson, 1934, reports the 

species from North Carolina to the West Indies.
PART 1. PELECYPODA 31

Subgenus PIAGIOCTENIUM Ball

1898. PlagiQCtenium Dall, Wagner Free Inst. Sci. Trans., vol. 

3, pt. 4, p. 696.

Type by original designation: Pecten ventricosus Sowerby= 

Pecten circularis Sowerby. Pleistocene of California. Recent 

from Monterey, Calif., to the Gulf of California and Paita, Peru.

Resembling Aequipecten but without radial striation; the 

concentric sculpture in looped lamellae; the ribs strong, frequently smooth above; the submargins impressed below the 

subequal auricles; the valves well inflated with a tendency 

to oblique growth in the adult.

To this very natural group belong nearly all the shallowwater pectens of our own coasts.—Dall, 1898.

Plagioctenium differs further from Aequipecten, 

under which it was included by Verrill and the earlier 

systematists, in the stronger, more regular ribbing and 

in the relative convexity of the valves. In Plagioctenium, as in Pecten s. s., the right valve is the more 

inflated. In Chlamys and in the subgenus Aequipecten 

the left valve is more convex than the right. Because 

of the form and outline the group has been referred to 

Pecten rather than to Chlamys.

Pecten (Plagioctenium) gibbus (Linnaeus) Dall

Plate 5, figure 3

1758. Ostrea gWba Linnaeus, Systema naturae, 10th edition, 

p. 698.

1822. Pecten dislocatus Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 2, p. 260.

1858. Pecten dislocatus Say. Holmes, Post-Pleiocene fossils of 

South Carolina, p. 12, pi. 2, fig. 12.

1889. Pecten irradians var. dislocatus Say. Dall, U. S. Nat. 

Mus. Bull. 37, p. 34.

1898. Pecten (Plagioctenium) gilibus Linnaeus. Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, p. 745.

1936. Pecten (Chlamys) gibbus Linnaeus. Mansfield, Jour. 

Paleontology, vol. 10, pp. 174, 182, 185.

O. testa radiis 20 glabris, gibba. Habitat in M. Americano.— 

Linnaeus, 1758.

Closely related but not specifically identical forms 

have been recovered from a few localities in the 

Miocene of Virginia and North Carolina. Pecten 

gibbus gibbus has not, however, been recorded from 

beds below the Pliocene. The distribution of the group 

is governed largely by temperature. In both the 

Tertiary and the Kecent it is widely distributed and 

diversified in the Floridian and mid-American faunas. 

The waters in which the middle and late Tertiary deposits of Virginia and North Carolina were laid down 

were apparently too cold for its favorable development.

Distribution: North Carolina: Pliocene, Waccamaw formation, Lake Waccamaw, Columbus County; Wilmington, New 

Hanover County.

Outside distribution: Pliocene, Caloosahatchee marl, De Leon 

Springs, Volusia County, Fla.; Kissimmee well (at a depth of 

150 feet), Osceola County, Fla.; Caloosahatchee River, Shell 

Creek, Alligator Creek, and Myakka River, Fla. Croatan sand, 

Slocums Creek and Mallisons, Craven County, N. C. 

Pliocene (?), Charlton formation, Orange Bluff, St. Marys

River, and 3 miles southeast of Folkston, Nassau County, Fla. 

Pleistocene, Simmons Bluff, S. C.; Orient, Hillsborough County, 

Fla.; North Creek, Manatee County, Fla.; Kissimmee (at a 

depth of 96 feet), Osceola County, Fla.; and Torch Key,. Fla. 

Recent, Hatteras to Brazil in less than 50 fathoms; Hatteras 

down to and including west Florida, the Gulf of Mexico, the 

West Indies, and the Antilles, all in more than 50 fathoms.

Genus CHLAMYS (Bolten) Roeding

1798. Chlamys (Bolten) Roeding, Museum boltenianum, pt. 2, 

Conchylia, p. 161.

Type by subsequent designation, Dall, Wagner Free Inst. 

Sci. Trans., vol. 3., pt. 4, p. 695, 1898: Pecten islandicus Miiller. 

Pleistocene of the boulder clays of the northeast coast and 

Recent from the Arctic region to the Chesapeake Bay.

Shell small or of moderate dimensions; inequilateral. 

Right valve slightly more compressed than the left but 

not conspicuously so. Dorsal margins steeply sloping. 

Sculpture radial, the lirae usually numerous and increasing by intercalation, imbricated by the concentric 

sculpture, persistent to the ventral margins, which are 

scalloped by the ribbing. Anterior auricles larger than 

the posterior, the right anterior notched for the 

extrusion of the byssus. The margin below the byssal 

notch pectinated. The cardinal margin of the auricles 

of both valves bent inward over the inconspicuous ligament—those of the right valve more forcibly - so. 

Resilium short and strong. Chondrophore small, 

trigonal, and subumbonal. Cardinal crurae not conspicuous. Characters of interior usually obscure, 

usually with ribs and double flutings corresponding to 

the external ribbing.

Chlamys is widely distributed. Many of the species 

are active swimmers and very brightly colored, 

especially those living in the warmer waters.

Chlamys decemnaria (Conrad) Dall

Plate 5, figures 1, 2, 6, 7

1834. Pecten decemnarius Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 151. 

1840. Pecten decemnarius Conrad, Fossils of the medial tertiary

of the United States, p. 49, pi. 24, fig. 2. 

1845. Pecten dispaiatus Conrad, idem, p. 74, pi. 42, fig. 3 (very

poor). 

1863. Pecten decemnarius Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, vol. 14, p. 581. 

1898. Pecten (Chlamys) decemnarius Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 741.

1936 (April). Pecten (Chlamys) decemnarius Conrad. Mansfield, Jour. Paleontology, vol. 10, pp. 174, 178, 184. 

1936 (November). Chlamys (Chlamys) decemnarius (Conrad).

Rowland, Am. Midland Naturalist, vol. 17, p. 1009, pi.

8, figs. 5, 6.

Shell ovate, slightly convex, with about 10 broad, flattened 

ribs disappearing on the umbo, some of them sulcated; radiating striae numerous, distinct, subscabrous; ears unequal.

I possess but a single superior valve of each of these pectens. 

Locality, same as the preceding [James River, Va.].—Conrad, 

1834.

This species is notably irregular in its sculpture, the disk 

being sculptured either by numerous more or less distinctly
32 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

fasciculated, small, radial threads, or the fasciculi may be replaced partially by stout, elevated, rounded ribs, with wide, 

radially threaded interspaces. The radial sculpture may be 

nearly smooth or covered with a conspicuous, dense, concentric 

lamellation. Three or four of the ribs may be more prominent 

than the others, and the smaller ones uneven in size and rugose, 

forming the variety dispalatus. When the fasciculi are riblike 

they are usually dichotomous. The umbonal region in typical 

decemnarius is usually feebly sculptured, but in the variety 

dispalatus the ribbing approaches the beaks more nearly. The 

type of the 'latter has been carefully compared, and the ears 

and surface agree exactly with those of the decemnarius form. 

Large valves of the latter attain a height and width of 68 

millimeters; the type of dispalatus measures 24 millimeters. 

The cardinal crura are parallel with the hinge line and moderately developed. The byssal notch is wide and conspicuous, 

the posterior ears small.

In sculpture this form almost exactly parallels the recent 

northwest American P. hericeus in its mutations.—Dall, 1898.

The plates represent end members of complete series 

of this exceedingly variable form.

Distribution: Virginia: Miocene, Yorktown formation. Indian Field Point, Yorktown, and Bellefield, York County; 

Sycamore and a quarter to half a mile below Sycamore, Southampton County.

North Carolina: Miocene, Yorktown formation. 1% miles 

above Murfreesboro and \ mile above Murfreesboro, Hertford 

County; Halifax, Halifax County; % mile above Bells Bridge 

and V8 mile below Bells Bridge, Edgecombe County; 2 miles 

west of Greenville, Pitt County.

Subgenus IYROPECTEN Conrad

]862. Lyropecten Conrad, Acad. Nat. Sci. Philadelphia Proc. for 

1862, p. 291.

Type by subsequent designation, Dall, Wagner Free Inst. 

Sci. Trans., vol. 3, pt. 4, p. 695, 1898: Lyropecten estrellanus 

Conrad. Miocene of the Pacific coast.

Inequivalve, radiately costate; hinge with a triangular pit 

as in Pecten and diverging prominent teeth on each side the 

ligament cavity.—Conrad, 1862.

The valves are generally large and coarse and both 

convex, the left valve slightly more inflated than the 

right. The costals, unlike those of Chlamys s. s., are 

relatively few in number but very heavy and not 

dichotomous.

Lyropecten is the dominant group in the Chesapeake 

Miocene, conspicuous both by reason of its abundance 

and by the large size of the individuals. The beginnings in the lower Miocene are very modest, possibly 

because the group had not reached the peak of its development, or possibly because the cooler climate of the 

Chesapeake was more favorable. The heavy pectens of 

the Miocene of south Europe, Gigantopecten Rovereto 

and its synonym Macrochlamys Sacco, are referable to 

Pecten rather than Chlamys because of the absence of 

a byssus. They differ from Pecten s. s. only in the 

slight convexity of the left valve.

Chlamys (Lyropecten) madisonia (Say) Glenn

Plate 4, figure 5; plate 9, figure 7

1824. Pecten madisonius Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. 134.

1840. Pecten madisonius Say. Conrad, Fossils of the medial

Tertiary of the United States, p. 48, pi. 24, fig. 1. 

1858. Pecten madisonius Say. Emmons, North Carolina Geol.

Survey Kept., p. 282, fig. 200.

1863. Pecten madisonius Say. Conrad, Acad. Nat. Sci., Philadelphia Proc. for 1862, vol. 14, p. 581. 

1894. Pecten madisonius Say. Whitfield, U. S. Geol. Survey

Mon. 24, p. 30, pi. 2, fig. 8; pi. 4, figs. 1-5. 

1898. Pecten (Lyropecten) madisonius Say. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 4, p. 724 (synonymy

excluded). 

1904. Pecten (Chlamys) madisonius Say. Glenn, Maryland

Geol. Survey, Miocene, p. 377, pi. C, fig. 1. 

1909. Pecten (Chlamys) madisonius Say. Grabau and Shimer,

North American index fossils, vol. 1, p. 502, fig. 673c. 

1928. Pecten madisonius Say. Mansfield, U. S. Nat. Mus. Proc.,

No. 2759, vol. 74, p. 10, pi. 2, fig. 1; pi. 3, fig. 1. 

1936. Pecten (Chlwnys) madisonius Say. Mansfield, Jour.

Paleontology, vol 10, pp. 174, 176,177,184.

Much compressed, with about 16 striated ribs.

Shell rounded, much compressed; the whole surface covered with scaly striae; ribs elevated, rounded, with about 3 

striae on the back of each; intervening grooves rather profound ; ears equal, sinus of the ear of the superior valve profound, extending at least one-third of the length of the 

ear.

Length rather more than 4% inches; breadth 4% inches. In 

magnitude this shell is justly entitled to compare with the preceding [Pecten jeffersonius Say]; but it differs, in being much 

less convex, and in having a much more profound sinus in the 

ear of the superior valve.—Say, 1824.

Type locality, Maryland.

Chlamys (Lyropecten) madisonia, when properly 

discriminated, is confined to the Calvert and Choptank 

formations. The later C. jeffersonia may, through 

santamaria Tucker and the subspecies middlesexensis 

Mansfield, be in the direct line of descent.

Typical Chlamys (Lyropecten) madisonia are relatively wide—wider than C. jeffersonia—and usually 

with 15 or 16 ribs. Each rib bears 3 scabrous lirae; and 

other lirae, less elevated than those upon the summits 

of the primaries, crowd the sides and the intercostal 

channels. The ears are low but wide, the byssal notch 

is very deep and the ctenolium coarse.

Distribution: Virginia: Miocene, Calvert and Choptank formations, Nomini Cliffs, Westmoreland County.

Outside distribution: Miocene, Calvert formation, Shiloh and 

Jericho, Cumberland County, N. J.; Church Hill, Centerville, 

Reeds and Wye Mills, Queen Annes County, Md.; Fairhaven and 

Lyons Creek, Anne Arundel County, Md.; Whites Landing, 

Magruders Ferry, and Trumans Wharf, Prince Georges County, 

Md.; Chesapeake Beach and Plum Point, Calvert County, Md. 

Choptank formation, Greensboro, Caroline County, Md.; Skipton, Cordova, Peach Blossom Creek, Dover Bridge, Trappe 

Landing, and Sand Hill, Talbot County, Md.; Governor Run, 

Flag Pond, and St. Leonard Creek, Calvert County, Md.; Jones 

Wharf, Cuckold Creek, Turner, and Pawpaw Point, St. Marys 

County, Md.

Chlamys (Lyropecten) jeffersonia (Say) Glenn 

Plate 4, figure 2

1824). Pecten jeffersonius Say, Acad. Nat. Sci. Philadelphia 

Jour., 1st ser., vol. 4, p. 133, pi. 9, fig. 1.
PART 1. PELECYPODA 33

1840. Pecten, jeffersonius Say. Conrad, Fossils of the medial 

Tertiary of the United States, p. 46, pi. 22, fig. 1.

1858. Pecten jeffersonius Say. Emmons, North Carolina Geol. 

Survey Kept., pp. 281, 282, figs. 199, 201.

1883. Pecten jeffersonius Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 581.

1898. Pecten (Lyropecten) jeffersonius Say. Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 4, p. 722.

1904. Pecten (Chlamys) jeffersonius Say. Glenn, Maryland 

Geol. Survey, Miocene, p. 378, pi. C., fig. 2.

1909. Pecten (Chlamys) jeffersonius Say. Grabau and Shimer, 

North American index fossils, vol. 1, p. 502, fig. 673f.

1932. Chlamys (Lyropecten) jeffersonius Say. Mansfield, Florida Geol. Survey Bull. 8, p. 59, pi. 11, fig. 1.

1936. Pecten (Chalmys) jeffersonius Say, Jour. Paleontology, 

vol. 10, pp. 174, 178, 179, 181, 184, 185.

Subequivalve, with from 9 to 11 striated ribs.

Shell rounded, convex, not quite equivalved, one of the valves 

being a little more convex than the other; the whole surface 

covered with approximate, scaly striae; ribs elevated, rounded, 

with 6 or 7 striae on the back of each; intervening grooves profound; ears equal; sinus of the ear of the superior valve not 

profound, being barely one-eighth part of the length of the ear; 

within with broad, rounded, flattened ribs.

Length 5%0 inches, breadth 5%o inches.—Say, 1824.

Type locality: Maryland [?].

Chlamys jeffersonia s. s. is a subcircular, somewhat 

inflated shell; the byssal ear is separated from the disk 

by a rather shallow notch and an ill-defined fasciole; 

the primary ribs number from 9 to 12 and are, in the 

adults, rather low, broad, and evenly rounded; in the 

young they are more angular; the secondary lirae, both 

on the disk and on the auricles, are subequal, fine, and 

minutely laminated; 4 to 7 is the usual number on the 

top of each primary.

Within the limits of the species, in the restricted 

sense, the most conspicuous variations occur in the degree of inflation of the valves; in the character of the 

byssal notch, which may approach that of Lyropecten 

madisonius Say in depth, though in such individuals 

the ear is higher and its dorsal margin more rounded 

than in the letter; in the primary ribs, which range in 

number from 9 to 15 and in character from broad and 

gently undulatory costae to sharply angular ones separated by equally angular interspaces, a type commonly 

exemplified in the young but rarely in the adults; and 

in the secondary threads, which may be almost smooth 

or may become minutely spinose.

Pecten magnolia Conrad, 1857, from the Miocene of 

California, so closely resembles C. jeffersonia that Grant 

and Gale considered them specifically identical. Mansfield (op. cit., p. 179) has indicated the differences. 

Lyropecten was one of the widely distributed and characteristic elements in the Miocene faunas of the New 

World, particularly in the cooler waters.

The following table shows the range in the number 

of ribs of 323 Lyropecten valves from 64 localities. 

The number seems to be fairly constant in a single 

locality, a fact that would invalidate the results unless 

the collection were very well balanced. The Chlamys 

jeffersonia material is, in all probability, sufficiently 

abundant and representative to correct all such errors. 

It is interesting to note the clear definition of the nodes, 

which indicate the triple separation of the species.

The italicized figures are quoted from Dall's computations.

Number of ribs

Chlamys (Lyropecten) jeffersonia (Say)- _ _ ____ __

Chlamys (Lyropecten) jeffersonia (Say) s. s_ __________

(Say). ——— ____ — _ ———— ___ — ____ ——— ___

Chlamys (Lyropecten) jeffersonia subsp. edgecombensis

(Conrad) __ _______ __________________________

6

t

/1-

{.. {"

7

9

a>

Q

S

8

14

11

13

11

9

37

10

07

1 Q

10

36

9Q

qc

&Q

1

11

33i&

3?i&

1

12

26

7

94

?,

7

13

14

1

4

10

1

14

13

5

3

10

5

15

20

ff>

3

17

*

16

29&

29

9.

17

7 

1

7

1

18

1

1

19

1

1

20

1

1

21

0

0

22

1

1

Chlamys (Lyropecten) jeffersonia (Say) s. s. is most 

abundantly represented in the Yorktown formation in 

Virginia at Lanexa, along the James River, and in 

Southampton County; and in North Carolina in Hertford, Halifax, Edgecombe, and Pitt Counties. In Virginia the usual number of primary ribs is 9 or 10; in 

North Carolina, 11 or 12.

Distribution: Virginia: Miocene, Yorktown formation, Lanexa, 

New Kent County; Yorktown, Bellefield, and Indian Field Point, 

York County; 3 miles northeast of Walkerton, King and Queen 

County; near the mouth of Baileys Creek, Prince George County; 

Petersburg, Dinwiddie County; Kings Mill, James City County; 

old Claremont Wharf, Claremont Wharf, Schmidts Bluff, 6% 

miles below Claremont Wharf, Sunken Marsh Creek, Cobham 

Wharf, Surry County; iy2 miles west of Smithfield, iy2 miles 

above Zuni, 2% to 3 miles northwest of Zuni, 6x/6 to 7 miles below

Zuni, 7 to 7% miles below Zuni, and 8 to 8% miles below Zuni, 

Isle of Wight County; Hitchcock, Greensville County; Delaware 

Park, Maddelys Bluff, 3 to 4 miles above the lower Seaboard 

Railway bridge, and % to % mile above the lower Seaboard Railway bridge, Southampton County; % mile east of Everets, Exit, 

1% miles southeast of Reids Ferry, iy2 miles north of Suffolk, 

5% miles northwest of Suffolk, 1 mile west of Suffolk, and % 

mile below the Suffolk waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Branches Bridge, 1 mile above Branches Bridge, Branches 

Bridge, Northampton County; 2% miles northwest of Murfreesboro, iy2 miles above Murfreesboro, 1 mile above Murfreesboro, 

near Murfreesboro, Dogwood Landing, Hertford County; Halifax, iy2 miles northeast of Enfield, y2 mile west of Enfield, and 

Palmyra Bluff, Halifax County; Compass Creek (1 mile from 

mouth), 15% miles above Bells Bridge, y2 mile above Bells 

Bridge, y8 mile below Bells Bridge, 1 mile below Bells Bridge,
34 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Tarboro, 1 mile above old Sparta Bridge, and Shiloh Mills, 

Edgecombe County; 8 to 9 miles west of Greenville, 3 miles 

west of Greenville, 2 miles west of Greenville, 1% miles west 

of Greenville, and Greenville (just south of the county bridge), 

Pitt County; 1% miles northeast of Chocowinity, Beaufort 

County; 6 miles west of Goldsboro, Wayne County; 4 miles east 

of Lizzie, Greene County.

Outside distribution: Duplin marl, Porters Landing on the 

Savannah River, Effingham County, Ga.; Brunswick River bed, 

Brunswick, Glynn County, Ga. Choctawhatchee formation, 

northern Florida.

Chlamys (Lyropecten) jeffersonia septenaria (Say) Mansfield

Plate 4, figure 1

1824. Pectcn septenarius Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. ]36, pi. 9, fig. 3.

1840. Pecten septenarius Say. Conrad, Fossils of the medial 

Tertiary of the United States, p. 47, pi. 22, fig. 2.

1856. Pecten septenarius Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 31, pi. 13, figs. 1-4.

1863. Pecten septenarius Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 581.

1898. Pecten jeffersonius var. septenarius Say. Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 722.

1901. Pecten jeffersonius var. septenarius Say. Glenn, Maryland Geol. Survey, Miocene, p. 379, pi. C, fig. 4.

1936. Pecten (Chlamys) jeffersonius septenarius Say. Mansfield, Jour. Paleontology, vol. 10, pp. 174, 179, 184, 185.

Shell convex, suborbicular; auricles subequal; surface with 

numerous slightly scaly striae, and about 7 remote ribs, of 

which the 3 intermediate ones are much elevated, rounded, 

or slightly flattened on the top.

Length nearly 2.7 inches. The striae are equally distinct on 

the ribs and in the intermediate spaces. The scales are rather 

thick, very small, and not confined to the striae, but are also 

observable in the spaces between the striae.—Say, 1824.

Type locality: Maryland[?].

Chlamys (Lyropecten) jeffersonia subsp. septenaria 

is characterized by fewer primary ribs, normally 7 or 

8, rarely only 6. As might be inferred, these are 

broader and usually stronger than in the forms on 

which the costae are more numerous.

The subspecies is less abundant and more restricted 

stratigraphically than Chlamys jeffersonia. (See Mansfield, op. cit., p. 179.)

Distribution: Virginia: Miocene, Yorktown formation. Lanexa, New Kent County; Clareniont Wharf, Schmidts Bluff, 

8~y2 miles below Claremont Wharf, Sunken Marsh Creek, Surry 

County; Petersburg, Dinwiddie County; James River, 7 to 7^ 

miles below Zuni, Isle of Wight County; 3 to 4 miles above 

the lower Seaboard Railway bridge, at the lower Seaboard 

Railway bridge, Southampton County; Exit, 1 mile west of 

Suffolk, and % mile below Suffolk, Nansemond County.

North Carolina: 1 mile above Branches Bridge, Northampton County; Miocene, Yorktown formation. Halifax and 

Palmyra, Halifax County; y8 mile below Bells Bridge, % mile 

below Bells Bridge, 1 mile below Bells Bridge, and Shiloh 

Mills, Edgecombe County; 8 to 9 miles west of Greenville and 

at Greenville, Pitt County. Duplin marl, Natural Well?, Duplin 

County.

Chlamys (Lyropecten) planicosta Gardner, n. sp.

Plate 9, figure 1

Valves large, subcircular, slightly convex; primary 

radials 19 in number, very low, broad, rectangular in 

cross section, reaching a maximum of 7 millimeters in 

breadth, sculptured with very faint striae, obsolete except toward the margin; interradials half as wide as 

the radials, filled mostly with a strongly rounded intercalary tending to bifurcate near the ventral margin; 

concentric sculpture very fine, visible principally in the 

spaces between the primaries and the midrib; anterior 

right ear only preserved and that badly broken; notch 

probably rather deep; fascicle conspicuous, lamellar; 

right auricle sculptured with 7 unequal striae separated 

by unequal interspaces; resilial pit wide and rather 

shallow; ligamental groove deep, bounded on the inner 

margin by a cardinal rib which, however, becomes 

obsolete anteriorly; two pairs of narrow, pinched ridges 

radiating from the apex of the pit—one at the margin 

of the pit, the other halfway down the sides—which 

may or may not be an accidental character.

Dimensions of holotype: Height 111.0 millimeters, 

width 118.0±millimeters. Holotype, a right valve: 

U. S. Nat. Mus. 325493.

Type locality: 3 miles southwest of Frog Level (on 

J. A. Noble's branch), Pitt County, N. C.

The single valve, though badly battered, is so distinct 

and so well characterized that it has seemed worth 

while to describe it. It may be readily isolated by the 

rectangular cross section of the primary ribs, their very 

fine radial striation, and the prominence of the intercalated midrib.

Distribution: North Carolina: Miocene, Yorktown formation, 

3 miles southwest of Frog Level (on J. A. Noble's branch), 

Pitt County.

Section NODIPECTE1T Dall

1898. Nodipecten Dall, Wagner Free Inst. Sci. Trans. vol. 3, 

pt 4, p. 695.

Type by original designation: Ostrea nedosa Linnaeus. Pliocene of Florida, Pleistocene and Recent of the Gulf of Mexico 

and the Antilles.

Shell-like Lyropecten, but the ribs intermittently nodose, 

with more or less prominent hollow nodes or bullae; radial 

striation pronounced; ears unequal, the posterior smaller, the 

valves often more or less oblique; imbricate surface layer 

sometimes very marked.—Dall, 1898.

Chlamys (Lyropecten) ernestsmithi (Tucker) Tucker

Plate 6, figures 6-8

1931. Pecten ernestsmithi Tucker, Indiana Acad. Sci. Proc., vol.

40, p. 244, pi. 1, figs. 1, 3, 4. 

1933. Pecten ernestsmithi Tucker, Bull. Am. Paleontology, vol.

18, p. 66, pi. 11 (2), fig. 13. 

1936. Pecten (Chlamys) ernestsmithi Tucker. Mansfield, Jour.

Paleontology, vol. 10, pp. 174,183,185.

Shell ovate, rather large, heavy, with 5 ribs, 3 of which are 

better developed. The ribs are broad and rounded on their
PART 1. PELECYPODA 35

summits and show a marked tendency to become nodose from 

the umbonal region to the periphery. Interspaces wider than 

the ribs and deeply channeled. Both ribs and interspaces 

strongly radially threaded. A fragment of a right valve shows 

a strongly developed, concentric sculpture of scaly lamellae 

over both ribs and interspaces. Beak narrow and quite pointed. 

Submargins narrow, the outer margins nearly smooth, the inner 

radially threaded like the rest of the disk. Ears large, unequal, 

and radially threaded. Anterior byssal ear quite pointed and 

somewhat corrugated along the cardinal margin. Posterior ear 

somewhat less strongly threaded. Byssal sinus deep, narrow, 

and inconspicuous. Fascicle broad. Interior fluted to the umbones. Margins crenulated. Ctenolium consists of 6 prominent 

denticles. Resilial pit narrow, trigonal; lateral margins elevated. Cardinal margin of the right valve bent over the left. 

Provinculum strongly developed. Valve retains traces of a 

blotchy color pattern. Height 85, length 82.5, length of hinge 

line 60. and convexity about 20 millimeters.

This species differs from P. caloosaensis Dall in the shape of 

the ears, in the width of the interspaces, and in sculpture. P. 

ernestsmithi shows a well-developed sculpture of radial threads, 

while in caloosaensis the interspaces are sculptured only with 

feeble concentric lines. The anterior byssal ear of ernestsmithi 

is much more pointed at the cardinal margin than that of 

caloosaensis.

Holotype: Deposited Museum Paleontology, Cornell University.

Range: Pliocene.

Locality: Keith's marl pit, Neills Eddy Landing, Cape Fear 

River, 5 miles from Acme, N. C.—Tucker, 1931.

The specimens figured from the collections in the 

United States National Museum are rather better than 

the holotype.

Shell large, moderately convex. Primary radial 

sculpture of 4 or 5 strong, undulating ribs and of 2 

slightly less. prominent ones near the submargins; 

secondary, of strong, rounded cords numbering 6 to 8 

on each primary, equal in strength on the radial and 

interradial areas, separated from one another mostly by 

linear interspaces; the medial riblet of the intercostals 

occasionally made more conspicuous than the others by 

wider channels, which set it apart from the adjacent 

secondaries. The concentric sculpture—the characteristic feature of the shell—consists of very close-set 

imbrications that override the secondaries of both the 

costal and the intercostal areas; in many individuals a 

suggestion of concentric undulations on the primaries, 

but these are never so strongly developed as in the type 

of Nodipecten. Submargins rather wide, not very 

sharply differentiated; inner submargins sculptured 

with concentrically imbricated lirations, usually 5 to 

8; outer submargins smooth, the posterior wider than 

the anterior, the latter often obsolete in the right valve. 

Auricles large, widest at the cardinal margin; distal 

angles acute; right ear sculptured with 5 or 6 strong 

radial threads, separated by linear interspaces and 

overrun by concentric imbrications similar to those on 

the disk; left auricle sculptured with 8 to 12 feeble 

striations, unequal in width and separated by unequal 

interspaces, concentrically wrinkled but not imbricated; left ear in some individuals joined to the disk 

by a sharp angulation, in others by a concave area. 

Byssal notch probably deep; fasciole conspicuous. 

Ctenolium well-developed. Resilial pit narrow, deep, 

somewhat oblique. Hinge area in young furnished 

with feeble cardinal crura, which become obsolete in 

adults and are replaced by a wide ligamental area. 

Muscle scar slightly posterior and dorsal. Inner surface of valves strongly undulated by primaries. Ventral margin crenulated by secondaries.

Dimensions of figured specimens (U. S. Nat. Mus. 

No. 325492) : Right valve: Height 70.0 millimeters, 

width 67.0 millimeters. Left valve of another individual: Height 101.5 millimeters, width 100.0 

millimeters.

Both the figured specimens were collected from the 

Waccamaw formation at Walkers Bluff, Bladen 

County, N. C.

This fine species is separated from G. caloosaensis 

Dall, of the Florida Pliocene, by the sculptured intercoastal areas; and from C. peedeensis (Tuomey and 

Holmes) (pi. 6, fig. 5), of the South Carolina Miocene, 

and from C. nodosa Linnaeus, of the Recent fauna of 

the east coast, by the absence of well-defined nodes, by 

the fewer, coarser primaries, and by the stronger, more 

crowded concentric imbrications.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff, Bladen County; Neills Eddy Landing, 

Columbus County. This species, though by no means abundant, 

is fairly well represented at these two localities.

Subgenus AEaTTIPECTElT Fischer 

1886. Fischer, Manuel de conchyliologie, p. 944.

Type by monotypy: Ostrea opercularis Linnaeus. Recent in 

European waters.

Shell rather thin, brittle, of moderate dimensions, 

the circumference between the dorsal margins an arc 

of not far from 270°. Left valve more inflated than 

the right and more deeply colored. Primary ribbing 

regular, the number not increased by intercalation; a 

secondary liration frequently developed on both radial 

and interradial areas. Auricles fairly large, subequal. 

Byssal notch deep; Ctenolium strong. Dorsal margin 

of right valve bent sharply downward to contact the 

erect margins of the left valve. Inner dorsal margins 

reinforced by a single pair of cardinal crurae. 

Marginal ligament grooves shallow, the chondrophore 

rather small and not very deep. Single muscle impression obscure, circular, and included mostly within 

the upper posterior quadrant. Inner margins crenate, 

in harmony with the primary ribbing.

Aeguipecten is set apart by the not very marked 

difference in the inflation of the valves, the gently 

sloping dorsal margins, and the absence of intercalated 

primaries.
36 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Chlamys (Aequipecten) eborea (Conrad) Mansfield

Plate 7, figures 1, 5, 6, 8

1833. Pecten eboreus Conrad, Am. Jour. Sci., 1st ser., vol.

23, p. 341. 

1840. Pecten eboreus Conrad, Fossils of the medial Tertiary of

the United States, p. 48, pi. 23, fig. 2; pi. 24, fig. 3.

1843. Wecten vicen&rius Conrad, Acad. Nat. Sci. Philadelphia 

Proc., vol. 1, p. 306. (Immature shell.)

1844. Wecien holbrookii Ravenel, idem, vol. 2, p. 96.

1855. Pecten eboreus Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 28, pi. 11, figs. 1-5. 

1858. Pecten eboreus Emmons, North Carolina Geol. Survey

Kept., p. 279, fig. 197. 

1898. Pecten (Plagioctenium) eboreus Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 749. 

1932. Chlamys (Plaffioctenium) eboreus eboreus Conrad.

Mansfield, Florida Geol. Survey Bull. 8, p. 60, pi.

12, fig. 11. 

1936. Pecten (Chlamys) eboreus eboreus Conrad. Mansfield,

Jour. Paleontology, vol. 10, pp. 174, 180, 181, 184.

Shell suborbicular, compressed, thin, a little oblique; ribs 

about 22, rounded, little elevated, and smooth; inferior valve 

nearly flat. Length 2 inches. Locality, Suffolk, Va., Upper 

marine.—Conrad, 1833.

Computations on the primary radials of 404 valves 

of this species yield the following results:

95

59

31

5

2

1

As in Lyropecten, the number of ribs at a single locality is fairly constant; furthermore, the tendency toward uniformity is exhibited not only by all individuals of a species but also by all species of a group. 

Thus in the very fine, clean, sandy marls of Lanexa, 

in which the 8-, 9-, and 10-ribbed Chlamys (Lyropecten) jeffersonia were very abundant, the primary 

costae of G. (Aequipecten) chorea run as follows:

17 _ _

18 __ _ _ .

19 _

20 __ _ .

21 „ __

22 _

23

2

. __ __ 2

_ 7

26

. __ _ _ 32

. __ _ 70

. __ _ _ 72

24 __ _„ __

25 _ _ _

26 _ __ _ _

27

28- _ _

29 ________

19

20

21.

22.

23.

24.

14

3

1

In the coarser and slightly higher sands iy2 miles 

north of Suffolk, on the other hand, the many-ribbed 

forms of G. jeffersonia are abundant, and the following table shows the prevalence of the more numerous 

costae among the specimens of eborea:

22

23

24

25

1 26 _______________ 7

1 27 _______________ 0

28 _______________ 0

29 _______________ 1

The subdivisions established by Dall on the variations in the minor details of the sculpture have not 

been used here because of the many intermediate forms 

and the almost endless combinations of minor 

differences,

The length of the locality lists is conclusive evidence 

of the extensiveness of its occurrence. In most beds— 

particularly toward the south and in the later formations—it is by far the most profuse representative of 

the genus.

Distribution: Virginia: Miocene, Yorktown formation, 3 

miles northeast of Walkerton, King and Queen County; Petersburg, Dinwiddie County; 2 miles northwest of Smithfield, 1% 

miles west of Smithfield, % mile northeast of Smithfield, 1% 

miles northeast of Smithfield, 5 miles northeast of Smithfield, 

at Benns Church, 6% to 7 miles below Zuni, 7 to 7% miles below Zuni, Isle of Wight County; Hitchcock, Greensville County; 

Sycamore and % to % mile above the lower Seaboard Railway 

bridge over Meherrin River, Southampton County; }4 mile 

north of Chuckatuck, % mile east of Everets, Exit, iy2 miles 

southeast of Reids Ferry, 5% miles northwest of Suffolk, 2% 

miles northwest of Suffolk, 1% miles northwest of Suffolk, 1% 

miles north of Suffolk, 1% miles north of Suffolk, 1% miles 

northeast of Suffolk, 1% miles southeast of Suffolk, and the 

drainage ditch of the Norfolk & Western Railway just east of 

Jericho ditch, Nansemond County.

North Carolina: Miocene, Yorktown formation, Branches 

Bridge, Northampton County; 2*£ miles northwest of Murfreesboro, 1% miles above Murfreesboro, near Murfreesboro, 3 to 4 

miles below Tar Ferry, Tar Ferry, 1% miles below Tar Ferry, 

Dogwood Landing, and Mount Pleasant Landing, Hertford 

County; Colerain Landing, Mount Gould Landing, and % to 

% mile above Edenhouse Point, Bertie County; Halifax, 

Palmyra Bluff, and 3% miles below Palmyra Bluff, Halifax 

County; Hamilton Bluff, 4 miles northwest of Williamston, 

2% miles northwest of Williamston, and 1 mile northwest of 

Williamston, Martin County; 3% miles northwest of Rocky 

Mount, 2 miles west of Rocky Mount, % mile north of New 

Bridge, 5 miles below New Bridge, 6 ^ miles below New Bridge, 

15% miles above Bells Bridge, y2 mile above Bells Bridge, 

% mile below Bells Bridge, 1 to 1^4 miles below Bells Bridge, 

Shiloh Mills, Tarboro, and 1 mile below old Sparta Bridge, 

Edgecombe County; 2 miles below Toddy Station, 2 miles southeast of Tugwell, 1% miles northeast of Farmville, 3 miles 

south of Farmville, 2% miles north of Standard, 3 miles southeast of Frog Level, 8 to 9 miles west of Greenville, 3 miles 

west of Greenville, 2 miles west of Greenville, iy2 miles northwest of Greenville, Greenville (just south of the county bridge), 

1% miles east of Greenville, 6 miles below Greenville (at Cherry 

Landing), 6% miles below Greenville (at Taft's Landing), 9 

to 10 miles south of Greenville, Hardees Creek (about 3% miles 

from the Tar), 1 mile northwest of Galloway Crossroads, % 

mile north of Grimesland, Grifton, and 3 miles east of Grifton, 

Pitt County; 2% miles northwest of Chocowinity and 

1% miles northwest of Chocowinity, Beaufort County; Hominy 

Swamp near Wilson, 1 mile west of Wilson, 3 miles eastsoutheast of Wilson, 5 miles south of Wilson, and 1 mile northwest of Stantonsburg, Wilson County; 1 mile north of Castoria, 

% mile east of Lizzie, 1 mile east of Lizzie, 2 miles northeast 

of Lizzie, and 4 miles east of Lizzie, Greene County; 6 miles 

west of Goldsboro, Wayne County; Rock Landing, Craven 

County. Duplin marl, 2% miles south of Clinton, 3 miles 

south of Clinton, and 4 miles south of Clinton, Sampson County; 

2 miles northeast of Warsaw, Natural Well and environs, 

Duplin County; 1 mile west of Lumberton, Lumberton (near 

the bottling works), 2 miles below Lumberton, 4 to 5 miles 

below Lumberton, Fairmont, 1% miles northeast of Fairmont, 

and 4 miles northeast of Fairmont, Robeson County. Pliocene, 

Waccamaw formation, Black Rock Landing, 4 miles east of 

Elizabethtown, and Walkers Bluff, Bladen County; Neills Eddy 

Landing, Columbus County; Wilmington, New Hanover County,
PART 1. PELECYPODA 37

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Duplin marl, Darlington, Darlington County, 

S. C.; Porters Landing on the Savannah River, Effingham County, 

Ga., Pliocene, (?) Santa Rosa and Santa Maria Tetetla, Vera 

Cruz, Mexico; Tuxtepec, Oaxaca, Mexico. Waccamaw formation, 

Todds Ferry, Horry County, S. C., Caloosahatchee marl, Caloosahatchee River, and Shell Creek, Fla.

Chlamys (Aequipecten) comparilis (Tuomey and Holmes) 

Mansfield

Plate 7, figures 2, 3, 4, 7

1855. Pecten comparilis Tuomey and Holmes. Pleiocene fossils of South Carolina, p. 29, pi. 11, figs. 6-10.

1898. Pecten eboreus var. comparilis Tuomey and Holmes. Dall, 

Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, p. 750.

1932. Chlamys (Plagioctenium) comparilis Tuomey and 

Holmes. Mansfield, Florida Geol. Survey Bull. 8, p. 

61, pi. 11, figs. 5, 6.

1936. Pecten (Chlamys) comparilis Tuorney and Holmes. 

Mansfield, Jour. Paleontology, vol. 10, pp. 174, 180, 

181, 184, 185.

Shell orbicular, convex, somewhat thick, equivalve, with concentric lines of growth, ears nearly equal. Lower valve, buccal 

ear notched, radiately and coarsely ribbed, with 5 to 6 ribs; 

anal ear, ribs smaller and more numerous. Upper valve, ears 

with the radiating lines equal, ribs and interstices nearly equal.

This fossil is distinguished from P. eboreus by having the 

ribs more raised and convex, both valves more convex, and by 

the coarse ribs of the buccal ear of the lower valve.—Tuomey 

and Holmes, 1855.

The characters that separate C. comparilis from C. 

eborea, with which it has been commonly confused, 

are well illustrated in the original figures.

The species is restricted to a few localities at the 

top of the Miocene and the base of the Pliocene scattered from southern Virginia to Florida. In Florida 

C. comparilis has been recognized only in the 

Cancellaria zone.

Distribution: The recorded distribution of Pecten comparilis 

Tuomey and Holmes (Pleiocene fossils of South Carolina, p. 29, 

pi. 11, figs. 6-10) is as follows: Yorktown formation at Petersburg and 16 miles below Suffolk, Nansemond River, Va., one 

specimen in the United States National Museum collected by 

the late Frank Burns from each locality; upper Miocene at 

Darlington, S. C. (Tuomey and Holmes) ; Pliocene at Goose 

Creek, S. C.; upper Miocene bed at Porters Landing on the 

Savannah River, Ga.; and upper Miocene (Cancellaria zone), 

Florida.—Mansfield, W. C., Jour. Paleontology, vol. 10, No. 3, 

p. 180, April 1936.

Subgenus PLACOPECTEN Verrill

1897. Placopecten Verrill, Connecticut Acad. Arts and Sci. 

Trans., vol. 10, p. 69.

Type by original designation : Pecten clintonius Say. Miocene 

of Virginia.

Verrill describes Placopecten as a subgenus of 

Chlamys. A number of authors, including Dall, have 

considered it closer to Pecten, although Dall mentions 

the similarity of a Placopecten clintonius to a hypothetical Lyropecten jeffersonius with obsolete primary 

ribbing. Placopecten resembles Chlamys in the relatively greater compression of the right valve. In true 

Pecten the right valve is more highly inflated than the 

left. The byssal sinus of Placopecten is more shallow 

than that of true Chlamys, and the pectenidial teeth 

are usually obsolete in the adults. In form and texture 

the Placopecten approach Amusium, but they are 

sharply separable by the absence of internal ribbing.

Chlamys (Placopecten) clintonia (Say) Verrill

Plate 6, figures 1, 4

1824. Pecten clintonius Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. 135, pi. 9, fig. 2.

1834. Pecten magellanicus Conrad, idem, 1st ser., vol. 7, p. 153. 

Not Ostrea magellanica Gmelin, 1792.

1840. Peoten clintonius Say. Conrad, Fossils of the medial Tertiary of the United States, p. 47, pi. 23, fig. 1.

1858. Pecten princepoides Emmons, North Carolina Geol. Survey Rept., p. 280, fig. 198.

1863. Pecten clintonius Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 581.

1897. Chlamys (Placopecten) clintonius Say (part). Verrill, 

Connecticut Acad. Arts and Sci. Trans., vol. 10, p. 78.

1898. Pecten (Placopecten) clintonius Say. Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 4, p. 725.

1904. Pecten (CMamys) clintonius Say. Glenn, Maryland Geol. 

Survey, Miocene, p. 375, pi. 99, fig. 5.

1936. Pecten (Chlamys) clintonius Say. Mansfield, Jour. Paleontology, vol. 10, pp. 174, 178,184, pi. 22, fig. 4.

Auricles equal; surface with from 140 to 180 elevated longitudinal lines.

Shell suborbicular, compressed, with very numerous, regular, 

elevated striae, which are muricated with minute scales formed 

by transverse wrinkles that are sparse in the middle of the 

length and crowded on each side of the shell; the intervening 

spaces are regularly concave and in parts very distinctly wrinkled ; auricles equal, striated like the general surface; within 

simple, margin striated.

Length 4 inches, breadth rather more.

This is a very fine shell comparable with the mageUanica; but 

the sides below the auricles decline much more rapidly toward 

the base, and the striae, judging from Bruguiere's figure, are 

much more prominent and distinct.—Say, 1824.

Type locality: Maryland [ ?].

Verrill united the Miocene species with the Recent 

Pecten magellanicus, its undoubted descendant, but 

Dall, op. cit, 1898, later excluded the Recent species because of "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 fossil are markedly 

coarser than those of the living species. In both, the 

byssal notch of the adult is represented by a shallow 

sinuation, and the ctenolium, present in the immature 

stages, is usually buried in shelly matter in the adult."

The species is well characterized by the thin, compressed shell, the hyaline texture of the interior surface, 

and the very numerous, irregularly wrinkled, radial 

lirations of the exterior surface, which are coarser than 

those of the Recent magellanica. The concentric ornamentation is visible only in the interspaces and on the 

auricles and submargins, where it is sometimes strong
38 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

enough to muricate the lirae. It is interesting to note 

that in the closely allied Recent species the individuals 

that develop a sculpture most nearly akin to that of 

Placopecten clintonius (Say) come from warmer 

waters.

The pectens described by Say in 1824 are among 

the most common in the Miocene faunas of the middle 

States of the Atlantic seaboard. They were included 

in "a very large and fine collection of fossil shells 

which Mr. John Finch obtained with much labor and 

some expense in Maryland and which that gentleman 

with great liberality submitted" to Thomas Say for 

examination. The following footnote attends Pecten 

Clintonius: "Mr. Finch requested that three species 

of his collection that might prove to be new should be 

dedicated to the distinguished men whose names these 

shells bear." Thomas Jefferson, James Madison, and 

DeWitt Clinton were thus honored. DeWitt Clinton 

was in 1824 a prominent national figure. He had been 

United States Senator from New York, mayor of New 

York City, governor of New York, and in 1812 a 

formidable candidate for the presidency. The Great 

Lakes to Hudson River Canal was begun and completed largely through his efforts. He was an educator 

and a naturalist, the second president of the American 

Academy of Art, and the founder and an early 

president of the New York Historical Society.

Mansfield (op. cit., p. 178) has expressed on the 

printed page the doubt held by many students that 

the Finch collection included only Maryland shells. 

It is highly probably that not only Pecten clintonius 

Say but also Say's P. jeffersonius and P. septenarius 

came from the Yorktown formation in Virginia, at 

a horizon higher than any recognized in the Miocene 

section of Maryland.

Distribution: Virginia: Miocene, Torktown formation. 

Lanexa, New Kent County; Indian Field Point and Torktown, 

York County; mouth of Baileys Creek, Prince George County; 

old Claremont Wharf, Schmidts Bluff, 8% miles below Claremont Wharf, Sunken Marsh Creek, and Cobham Wharf, Surry 

County; Kings Mill, James City County; 1 mile above Zuni, 

just south of Zuni, 6% to 7 miles below Zuni, and 7 to iy2 

miles below Zuni, Isle of Wight County; Sycamore, 

Southampton County.

North Carolina: Miocene, Torktown formation, 1% miles 

above Branches Bridge, Northampton County, 2y% miles above 

Murfreesboro, 1 mile above Murfreesboro, and near Murfreesboro, Hertford County; Halifax, Halifax County; 3 miles west 

of Greenville and 2 miles west of Greenville, Pitt County.

Chlamys (Placopecten) marylandica (Wagner) Glenn

Plate 5, figure 4; plate 6, figures 2, 3

1839. Pecten marylandicus Wagner, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 8, p. 51, pi. 1, fig. 2.

1863. Pecten marylandicus Wagner. Conrad, Acad. Nat- Sci. 

Philadelphia Proc. for 1862, vol. 14, p. 581.

1898. Pecten (Placopecten?} marylandicus Wagner (part). 

Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, 

p. 728.

1904. Pecten (Chlamys) marylandicus Wagner (part). Glenn, 

Maryland Geol. Survey, Miocene, p. 376, pi. 99, fig. 6.

1936. Pecten (Chlamys) marylandicus Wagner. Mansfield, 

Jour. Paleontology, vol. 10, pp. 174, 176, 177, 184.

Shell ovate, compressed; ribs numerous, consisting of narrow, 

nearly smooth striae disposed in pairs; interstitial spaces each 

with a carinated line; ears unequal; inferior valve very slightly 

convex; ribs similar to those of the opposite valve; inner 

margin of the valve with profoundly elevated lines.

Locality, Mehering [Meherrin] River, N. C. [ ?] This Pecten is 

allied to Pecten madisonius Say but can readily be distinguished 

by its want of broad, elevated ribs and a surface destitute of 

scales.—Wagner, 1839.

In external ornamentation the species ranges from 

individuals showing uniform radiating lirae similar 

to those of Placopecten clmtonius—though stronger 

and consequently less numerous—to individuals exhibiting true ribs that recall those of Lyropecten and that 

are sufficiently strong to crenulate the interior of the 

valves. The ribs do not, however, become so strong 

as in the typical madisonius, nor are they ever reduced 

to interareas between impressed lines, as in virginianus 

and certain representatives of tenuis. The delicate, 

concentric sculpture is visible in the interspaces, as in 

clintonius, but it does not imbricate the radial striations, as in many individuals of tenuis.

Distribution: Virginia: Miocene, Choptank formation, Nomini 

Cliffs, Westmoreland County.

Outside distribution: Miocene, Choptank formation, Dover 

Bridge, Queen Annes County, Md.; Governor Run, Flag Pond, 

• and St. Leonard Creek, Calvert County, Md.; Jones Wharf, 

Patuxent River, St. Marys County, Md.

Chlamys (Placopecten) virginiana (Conrad) Tucker

Plate 4, figure 3

1840. Pecten virginianus Conrad, Fossils of the medial Tertiary

of the United States, p. 46, pi. 21, fig. 10. 

1863. Pecten virginianus Conrad, Acad. Nat Sci. Philadelphia

Proc. for 1862, vol. 14, p. 582. 

1898. Pecten (Placopecten) virginianus Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 4, p. 727. 

1934. Chlamys (Placopecten) virgmianum Conrad (part).

Tucker, Am. Midland Naturalist, vol. 15, p. 617. 

1936. Pecten (Chlamys) viriginianus Conrad. Mansfield, Jour.

Paleontology, vol. 10, pp. 174, 178, 184.

Shell orbicular; inferior valve convex, with numerous irregular, impressed, radiating lines; sinus of the ear profound, and 

a deep groove margins the ear to the apex; the groove minutely 

pectinated.

Locality, near City Point, Va.—Conrad, 1840.

Later collections have revealed this species at several localities of the Yorktown though it is nowhere 

an abundant form. It shares with C. clintonia (Say) 

the thin convex valves and hyaline texture, though it 

exhibits a peculiar translucency not noted in any representative of C. clintonia. It differs, furthermore, 

in the smaller size, the deeper byssal notch, the more 

strongly developed ctenolium, and the details of the 

external sculpture. In place of the raised lirae of 

C. clintonia, it has irregular impressed lines that are
PART 1. PELECYPODA 39

irregularly spaced and that number 75 on the type. 

The dimensions are. as follows: Height 57.8 millimeters, width 58.8 millimeters, semidiameter 4.1 

millimeters.

Distribution: Virginia: -Miocene, Yorktown formation, City 

Point (Conrad) and the mouth of Baileys Creek, Prince George 

County; 12 to 14 miles below Zuni, Isle of Wight County; 

Delaware Park, Southampton County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Murfreesboro, Hertford County.

Genus AMTTSITTM (Bolten) Reeding

1798. Amusium (Bolten) Reeding, Museum boltenianum, pt. 2, p. 

165).

Type by subsequent designation (Herrmannsen, Indicis generum Malacozoorum, vol. 1, p. 47, 1846) : Ostrea pleuronectes 

Linnaeus. Recent in the Indo-Pacific.

The valves are commonly large, thin, feebly convex, 

and, like those of the true pectens, not attached by a 

byssus. Eadial sculpture is sometimes suggested by 

the color pattern but is rarely developed and is never 

strong. A concentric imbrication may be observed in 

some species, particularly toward the ventral margin. 

The discrepancy in ornamentation so common in 

Ps&udafmMssiimb is reflected in the discrepant coloring 

in Amusium s. s. In A. papyraceum, the Recent Antillean .shell, the right valve is white or bordered with 

pale yellow, but the left is a deep reddish or purplish 

brown. This general type of color holds throughout 

Amusium s. s. The lirae developed upon the inner surface of the disk are perhaps the most constant feature 

of the genus.

Like Pecten, Amusiurm may be traced back to the 

Mesozoic. The thin, internally lirate shells of Amusium require a much more specialized habitat than the 

heavy, externally ribbed shells of most of the Pecten 

group, and perhaps for this reason the genus is relatively rare.

Amusium mortoni (Ravenel) Conrad

Plate 8, figures 1, 2

1844. Pecten mortoni Ravenel, Acad. Nat. Sci. Philadelphia 

Proc., vol. 2, p. 96.

1855. Pecten mortoni Ravenel. Tuouiey and Holmes, Pleiocene 

fossils of South Carolina, p. 27, pi. 10, figs. 1, 2.

1858. Pecten mortoni Emmons, North Carolina Geol. Survey 

Rept, p. 281.

1863. Amusium mortoni Ravenel. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 582.

1898. Pecten (Amusium) mortoni Ravenel. Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 4, p. 757.

1904. Pecten (Amusium) mortoni Ravenel. Glenn, Maryland 

Geol. Survey, Miocene, p. 372, pi. 99, fig. 1.

1906. Amussium mortoni Ravenel. Bose, Inst. geol. Mexico Bol. 

22, pp. 24, 74, pi. 1, figs. 3, 6, 7, 9; pi. 8, figs. 1, 2; pi. 9, 

fig 3.

1909. Pecten (Amusium) mortoni Ravenel. Grabau and Shinier, 

North American index fossils, vol. 1, p. 508, fig. 680.

1932. Amusium mortoni Ravenel. Mansfield, Florida Geol. Survey BuU. 8, p. 64, pi. 11, figs. 2, 4.

1936. Amusium mortoni Ravenel. Mansfield, Jour. Paleontology, vol. 10, pp. 174, 180, 184, 185.

Orbicular, thin, both valves moderately convex, one more 

so than the other; outside, with numerous concentric obsolete 

striae; inside, with from 18 to 24 radiating double ribs, slightly 

elevated; ears large, subequal, striated externally.

This species is nearly allied to the P. pleuronectus and P. 

japonicus. It is found on my plantation, The Grove, in St. 

Thomas' Parish, about 17 miles from Charleston, and also on 

Goose Creek, at Mr. Henry Smith's, about 7 miles southwest 

from The Grove deposit, and 11 miles from Charleston; Cooper 

River being between these localities.

This shell is abundant at The Grove, but being large and 

thin it is generally broken in getting out the marl, and with 

the exception of a few small specimens I have not been able 

to procure a perfect valve.

The largest specimen in my possession, although not perfect, 

is sufficiently so to determine its size; it is 8% inches in 

diameter.

I take much pleasure in designating this shell by the name 

of our distinguished geologist, Dr. Samuel George Morton, of 

Philadelphia.—Ravenel, 1844.

Mansfield reports fragments of the species from a 

number of localities in the Ecphora and Cancellaria 

zones of northern Florida.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, 1% miles north of Magnolia, Duplin County. Pliocene, 

Waccamaw formation, Lake Waccamaw, Columbus County; 

Black Rock Landing on the Cape Fear River, Bladen County.

Outside distribution: Miocene, Santa Rosa and Santa Maria 

Tetetla, Vera Cruz, Mexico. St. Marys formation, Cove Point 

and Drum Point, Calvert County, Md. Choctawhatchee formation, northern Florida. Pliocene, Waccamaw formation, Todds 

Ferry, Horry County; The Grove, Cooper River, and Smith's, 

Goose Creek, Berkeley County, S. C. Caloosahatehee marl,- 

Caloosahatchee River and Shell Creek, Fla.

Family SPONDYLIDAE 

Genus PLICATTTLA Lamarck

1801. PHcatula Lamarck, Syst§me des animaux sans vertebres, 

p. 132.

Type by subsequent designation (Schmidt, C. F., Versuch 

iiber die beste Einricht, etc., pp. 61, 177, Gotha, 1818) : Spondylus plicatus Linnaeus. Recent in the Orient.

Shell small, inequivalve, flattened or slightly convex, 

trigonal-ovate to subcircular, often irregular, attached 

as a rule in the adult by the umbo of the right valve, 

which is the larger. Outer surface generally plicate, 

the folds commonly bifurcating. Ligament internal, 

lodged in a subumbonal cartilage pit between the twp 

heavy, divergent, transversely striated cardinal crurae. 

A single muscle impression in the adult, excentric and 

posterior. Pallial line entire. Margin fluted in harmony with the outer ribbing.

Plicatula differs from Spondylus in its small size, 

less ornate sculpture, and absence of auricles.

The genus, which is recorded in the early Mesozoic, 

culminated in the late Mesozoic and is represented by 

fewer than a dozen Recent species, mostly oriental in 

habitat.
40 MOLLTJSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Plicatula marginata Say 

Plate 11, figures 6, 8, 13, 14

1824. Plicatula marginata Say, Acad. Nat. Sci. Philadelphia 

Jour., 1st ser., vol. 4, p. 136, pi. 9, figs. 4a, b.

1845. Plicatula marginata Say. Conrad, Fossils of the medial 

Tertiary of the United States, p. 75, pi. 43, fig. 5.

1855. Plicatula marginata Say. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 24, pi. 7, figs. 11-14.

1858. Plicatula marginata Emmons, North Carolina Geol. Survey Kept., p. 283, fig. 203.

1863. Plicatula marginal a Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 582.

1898. Plicatula marginata Say. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 4, p. 764.

1932. Plioatula marginata Say. Mansfield, Florida Geol. Survey Bull. 8, p. 66, pi. 12, figs. 9,10.

Shell ovate-cuneiform, somewhat arcuated at base; with 

about 3 much elevated folds, producing very profound undulations on. the edge of the shell; the intermediate fold is bifid; 

the whole surface is marked by rather gross concentric wrinkles ; inner margin dusky or blackish, with a series of granules 

on one valve, received into corresponding cavities in the opposite valve.

Length 1% inches, breadth 1 inch.—Say, 1824.

Type locality: Maryland (?).

So far as the form of the shell is concerned, this species 

cannot be discriminated from P. gibtosa, but none of the specimens show any trace of the dark venous lines which are so 

characteristic of both recent and fossil specimens of gibbosa. 

In a very large series of the recent shell a few specimens will 

usually be found which have a diffused brownish blush instead 

of the brown lines; but these are so exceptional that I have 

felt the present species might be separated with propriety. In 

both, the differences of sculpture due to situs pass through a 

parallel series of mutations.—Dall, 1898.

This species is the only common representative of 

the genus occurring within the Virginia-North Carolina area. As is normal with attached forms, it shows 

a considerable amount of variation in outline and in 

the number and character of the radial plications. 

The narrow trigonal outline is characteristic of the 

forms with few ribs; the subcircular, of the forms with 

many. The species is exceedingly abundant along the 

Tar River, in Pitt County, N. C., and farther southeast, in the vicinity of Lizzie, in Greene County, N. C. 

A particularly large collection was made by L. W. 

Stephenson at Dog Swamp, 4 miles east of Lizzie. 

The range of variation in the number of ribs at this 

locality is as follows: 3 ribs, 2 right valves, 1 left 

valve; 4 ribs, 22 right valves, 40 left valves; 5 ribs, 77 

right valves, 101 left valves; 6 ribs, 54 right valves, 36 

left valves; 7 ribs, 14 right valves, 10 left valves; 8 

ribs, 1 right valve, 3 left valves. The data, based on 

the consideration of 170 right valves and 191 left valves, 

indicate that 5 is the average number of ribs and that 

there is a tendency toward fewer ribs in the left valve 

than in the right.

Distribution: Virginia: Miocene, Yorktown formation, 4 miles 

northwest of Walkerton and 3 miles northeast of Walkerton, King

and Queen County; Yorktown and Bellefield, York County; Claremont Wharf and old Claremont Wharf, Surry County; 2 miles 

below Peters Bridge, Sussex County; 1 mile north of Zuni, 7 

to 7y2 miles below Zuni, 12 to 14 miles below Zuni, 2 miles 

northwest of Smithfield, iy2 miles west of Smithfield, % mile 

northeast of Smithfield, 1% miles northeast of Smithfield, 5 miles 

northeast of Smithfield, and Benns Church, Isle of Wight 

County; Sycamore, 14 to % mile below Sycamore, Maddelys 

Bluff, Southampton County; a quarter of a mile north of 

Suffolk, iy2 miles northeast of Suffolk, 1 mile northeast of 

Suffolk, and half a mile below the Suffolk waterworks dam, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Branches Bridge, 1 mile above Branches Bridge, and 

Branches Bridge, Northampton County; iy2 miles above Murfreesboro, 1 mile above Murfreesboro, and near Murfreesboro, 

Hertford County; Palmyra Bluff, Halifax County; 3 miles west 

of Williamston, 2% miles northwest of Williamston, 1 mile 

northwest of Williamston, and Hamilton Bluff, Martin County; 

Qy2 miles below New Bridge, Swift Creek, 15^ miles above 

Bells Bridge, % mile above Bells Bridge, % mile below Bells 

Bridge, Shiloh Mills, Tarboro (at L. E. Fountain's farm), and 

1 mile below old Sparta Bridge, Edgecombe County; 2 miles 

below Toddy Station, 1*4 miles northeast of Farmville, 3 miles 

south of Farmville, 2% miles north of Standard, 8 to 9 miles 

west of Greenville (on the east side of Pinelog Branch), 3 miles 

west of Greenville, 2 miles west of Greenville, iy2 miles west 

of Greenville (on Schoolhouse Branch), Greenville (just east 

of the county bridge), 8 to 9 miles southeast of Greenville, 

9 to 10 miles south of Greenville, and 1 mile northwest of 

Galloway Crossroads, Pitt County; 2 miles northwest of Chocowinity, Beaufort County; 2 miles southwest of Maple Cypress, 

Craven County; 1 mile west of Wilson (at Hominy Swamp), 

1 mile south of Wilson, 3 miles east-southeast of Wilson, 1 mile 

northwest of Stantonsburg, Wilson County; 1 mile north of 

Castoria, y% mile east of Lizzie, 2 miles northeast of Lizzie, 

4 miles east of Lizzie, and 1% miles east of Ormondsville, Greene County, 1% miles below Tar Ferry, 3 to 4 

miles below Tar Ferry, and Dogwood Landing, Hertford 

County; Colerain Landing and Mount Gould Landing, Bertie 

County; Rock Landing, Craven County. Duplin marl, 2% miles 

south of Clinton, 3 miles south of Clinton, and 4 miles south of 

Clinton, Sampson County; 3 miles northeast of Warsaw, Magnolia, and Natural Well and environs, Duplin County; 4 miles 

north of Lumberton, 1 mile west of Lumberton, Lumberton 

(near the bottling works), 2 miles below Lumberton, 4 to 5 

miles below Lumberton, Fairmont, and 1% miles northeast of 

Fairmont, Robeson County. Pliocene, Waccamaw formation, 

Lake Waccamaw, Cronly, and Neills Eddy Landing, Columbus 

County; Wilmington, New Hanover County.

Outside distribution: Miocene, Choctawhatcb.ee formation, 

northern Florida. Duplin marl, Darlington, Darlington 

County, S. C.; Porters Landing on the Savannah River, 

Effiingham County, Ga. Pliocene, Waccamaw formation, Nixons, 

Tillys Lake, and Todds Ferry, Horry County, S. C. Caloosahatchee marl, De Leon Springs, Volusia County, Fla. Caloosahatchee River, Shell Creek, and Alligator Creek, Fla.

Superfamily A1TOMIACEA

Family ANOMIIDAE 

Genus PODODESMUS Philippi 1837

1837. Pododesmus Philippi, Wiegmann, Archiv Naturgeschichte, 

Jahrgang 3, Band 1, p. 385.

Type by monotypy: Pododesmus decipiens Philippi=Po(Zo<Je$- 

mus rudis Broderip. Recent in the West Indies.
PART 1. PELECYPODA 41

Section MONTA Gray 

1849. Monia Gray, Zool. Soc. London Proc., pt. 17, p. 121.

Type by subsequent designation (Bucquoy, Dautzenberg, and 

Dollfus, Mollusques marins du Roussillon, vol. 2, p. 41, 1888) : 

Anomia zealandioa Gray. Recent in New Zealand.

Shell ovate, not plicated; radiately ribbed. Perforation of 

lower valve large, only slightly embracing the large thin plug.— 

Gray, 1849.

The genus differs from Pododesmus in the possession 

of a much larger foramen.

Pododesmus (Monia?) philippi Gardner, n. sp.

Plate 3, figures 10, 11, 13

1904. fAnomia aculeata Gmelin. Glenn, Maryland Geol. Survey, Miocene, p. 369, pi. 98, figs. 2-5. Not A. aculeata 

Gmelin, 1792.

Shell of medium size, moderately compressed, subcircular, unusually symmetrical for the genus. Umbones slightly prominent, central, almost but not quite 

terminal. Sculpture of irregular but mostly continuous divergent striae, numbering about 24 to the centimeter, separated by linear interspaces; concentric 

sculpture of a few exaggerated growth lines, which 

override and groove the radials. Characters of interior generally effaced by weathering. Valves usually 

lined with a calcareous layer. Margins of ligament 

scar in the left valve sometimes thickened to form 

irregular crura—a variable feature, however, not exhibited by all individuals of the species. Byssal scar 

very large, placed directly beneath the umbones but a 

little behind the center of the valve. Adductor scar 

decidedly smaller than the byssal, situated in front of 

and a little to the left of the latter. Pallial line simple. 

Right valve represented by such fragmentary material 

that its characters are doubtful.

Holotype, a left valve: U. S. Nat. Mus. 325497.

Dimensions of holotype: Height 35.7 millimeters, 

width 36.0 millimeters, convexity 7.6 millimeters.

Type locality: 2y2 miles below Bayport, Middlesex 

County, Va.

As the section Monia is based primarily on the 

nature of the foraminal opening, the assignment of 

the species to this group is only tentative.

Externally the species suggests an abnormally large 

and regular Anomia aculeata Gmelin, though on the 

latter the radiating lirae are discontinuous and 

crowded with minute prickles, whereas on the former 

they are continuous, simple, or rather dissected by the 

concentric striae. The figured types in the collection 

of the Maryland Geological Survey are not sufficiently 

well preserved to show the diagnostic interior characters. The radials are more deeply furrowed by the 

concentric lines than in the majority of specimens 

from Virginia, but otherwise the forms are identical. 

The species is represented at several localities in Virginia, and along the Bappahannock and James Eivers 

it is quite abundant.

Distribution: Virginia: Miocene, St. Marys formation, 2% 

miles below Bowlers Wharf, Essex County; 2% miles below 

Bayport, Middlesex County; old Clarernont Wharf, Schmidts 

Bluff, and 8% miles below Claremont Wharf, Surry County.

Su'perfamily OSTRACEA

Family OSTREIDAE 

Genus OSTREA (Linnaeus) Lamarck

1758. Linnaeus, Systema naturae, 10th ed., p. 696. 

1799. Lamarck, Prodrome d'une nouvelle classification des coquilles: Soc. histoire nat. Paris Mem., p. 81.

Type by subsequent designation (Schmidt, C. F., Versuch 

fiber die beste Einricht, etc., pp. 69, 177, Gotha, 1818) : Ostrea 

edulis Linnaeus. Recent off the European shores from Iceland 

to the Adriatic.

Ostrea waccamawensis Gardner, n. sp.

Plate 3, figure 17

Shell of medium size, ovate-elliptical, nonplicate, the 

ventral margin very broadly and evenly rounded. 

Attached valve—the only one known—moderately concave. External sculpture of narrow, closely plicated 

laminae, densely packed on the surface of the shell; 

radial sculpture dominant in young, and concentric 

laminae not developed, the resultant sculpture suggesting that of Anomia aculeata, Gmelin. Hinge character obscured by extraneous material on the interior 

of the shell; hinge area probably narrow and rather 

low, with a moderately deep median groove. Shell 

margins finely rugose for approximately one-third of 

the distance from the beak to the ventral margin. 

Muscle impression not visible.

Dimensions of holotype: Height 68.0 millimeters, 

width 57.0 millimeters.

Holotype: U. S. Nat. Mus. 497063.

Type locality: Cronly, Columbus County, N. C.

Ostrea waccamawensis is conspicuously distinct from 

all the known east coast oysters by reason of the regularity of the outline and the heavy decoration of narrow, crinkled lamellae.

Distribution: North Carolina: Pliocene, Waccamaw formation, Cronly, Columbus County.

Order ANOMALODESMACEA

The Anomalodesmacea are a polyphyletic group, 

many of them modified by adaptation to a highly specialized habitat. Although they have been shuttled 

about in systematic arrangements, as a whole and in 

parts, they are commonly assigned a place following 

the Teleodesmacea. As they include several characteristic Mesozoic genera, such as Pholadomya 

and Liopistha, the evidence of the primitive stock 

seems sufficiently strong to warrant their retention near 

the Prioncdesmacea. Later, as the evolutionary changes 

are traced in the nepionic shells, it may be possible to 

treat the group in a less arbitrary manner.
42 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Superfamily ANATINACEA 

Family PEBJPLOMATIDAE 

Genus PERIPLOMA Sehumaeher

1817. Periploma Sehumaeher, Essai d'un nouveau systeme des 

habitations des vers testace"s, p. 115.

Type by monotypy: Periploma, inaequwalvis Sehumaeher. 

Recent in the West Indies.

Shell subnacreous, inaequivalve, nearly closed, oval 

or rounded; umbones opisthogyrate. Ligament internal, supported by two vertically or anteriorly directed 

chondrophores. Hinge edentulous. Muscle impressions unequal. Pallial sinus broad and shallow.

The genus is rare in the Tertiary, and the Eecent 

forms are mostly confined to the eastern coasts of the 

Americas.

Subgenus COCHLODESMA Couthouy

1839. Cochlodesma, Couthouy, Monograph on the family Osteodesmacea: Boston Jour. Nat. History, vol. 2, p. 170.

Type by monotypy: Anatma leana Conrad. Recent from the 

Gulf of St. Lawrence to North Carolina.

The subgenus is characterized by the compressed, 

tellinif orm outline and by the absence of a calcified rib 

supporting the chondrophore.

Periploma (Cochlodesma) antiqua Conrad

Plate 10, figure 3

1834. Anatina, antiqua Conrad, Acad. Nat. Sci. Philadelphia 

Jour., 1st ser., vol. 7, p. 130.

1838. Periploma antiqua Conrad, Fossils of the medial Tertiary 

of the United States, p. 16, pi. 8, fig. 3.

1863. Periploma antiqua Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, p. 572.

1873. Cochlodesma antiquatum Conrad, Verrill, Invertebrate 

animals of Vineyard Sound: U. S. Comm. Fish and 

Fisheries Rept, p. 673.

1903. Periploma (Cochlodesma) antiqua Conrad. Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1530.

Shell ovate, rather elevated, convex, thin, and fragile; with 

obsolete concentric sulci; beaks slightly prominent; fosset not 

oblique, elongated. Length 2 inches, height about 1% inches. 

Locality, Yorktown, Va.—Conrad, 1834.

The type remains unique. The fragment of a valve 

strongly suggesting Conrad's species but not possessing 

sufficient characters for a definite determination was 

collected from the Waccamaw marls at Walkers Bluff, 

in Bladen County, N. C. Another fragment, unlike 

any known species of Periploma but too imperfect to 

describe, has been found in the Yorktown S1/^ miles 

northwest of Chocowinity, in Beaufort County, N. C.

Distribution: Virginia: Yorktown formation, Yorktown, 

York County.

Family THRACIIDAE 

Genus THRACIA (Leach ms.) De Blainville

1824. Thracia (Leach ms.) De Blainville, Dictionnaire des 

sciences naturelles, vol. 32, p. 347.

1825. Thracia (Leach ms.) De Blainville, Manuel de malacologie,

p. 564.

1827. Thracia De Blainville, idem, planches, p. 660, pi. 76, fig. 7. 

1839. Thracia Leach. Couthouy, Boston Jour. Nat. History,

vol. 2, p. 129. 

1903. Thracia Blainille. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 6, p. 1522.

Type by elimination: Thracia corbuloidea De Blainville. 

Recent in the Mediterranean.

In 1824 De Blainville described at length the shell 

of Thracia and placed under it two sections: (A) 

Species that have a spoon-shaped process (cuilleron) 

in one valve only;, sole example, T. corbuloidea; (B) 

species that have a spoon-shaped process in each valve; 

sole example, T. pubescens Leach=Mya pubescens Linnaeus. De Blainvilles description in 1825 was a replica of that of 1824 except that in the next to the last 

line of the description of 1824 he wrote "une ligule abdominale;" in 1825, "une ligule palleale." In 1827 De 

Blainville published the figures to accompany the text 

of 1825 and also a few pages of "Nouvelles additions 

et corrections au genera," in which he made the following note on Thracia "Supprimez la division B, etablie 

sur une coquille que je n'avais pas vue, et qui parait 

n'etre autre chose que celle qui sert de type au genre 

OSTfiODESME * * *."

As De Blainville's observations were not entirely correct, his A and B divisions are no longer recognized; 

but he clearly expressed the wish to eliminate the shell 

he had not seen. T. corbuloidea, then, remains the 

unique example.

The shell of Thracia is thin, not nacreous but cellulocrystalline, transversely ovate to ovate-trigonal, broadly 

rounded in front, more or less produced, truncate, and 

gaping posteriorly. The right valve is larger and 

more inflated than the left, the right umbo higher than 

the left, and the ventral margin of the right valve extends beyond that of the left. The umbones are broad, 

placed a little in front of the medial line, inrolled, and 

at the extreme tips turned slightly backward. They 

are so closely in contact in some of the species, notably 

Thracia conradi Couthouy, that the shell is frequently 

worn through by friction of the opposing surfaces. 

The anterior lateral margin is, as a rule, broadly 

rounded, the ventral margin broadly constricted in 

front of the obtuse rostrum, and the posterior truncate 

or rounded. The only sculpture is a concentric wrinkling, incremental in character, and a surficial granulation. The living species are in some degree protected 

by a delicate periostracum. The ligament is short, 

marginal, and sunken. It is attached on each side to 

modifications of the posterior dorsal margins, which in 

the closed valves are spoon-shaped. The hinge is 

edentulous. In some species—but not in all—the inner 

extremity of the anterior dorsal margin of the left 

valve is raised into an inconspicuous subumbonal tubercle, and in other species an inconspicuous ossicle is
PART 1. PELECYPODA 43

developed on the anterior dorsal margin a little in 

front of the umbo. In most Thracia the shell is so thin 

that the muscle scars and moderately insinuated pallial 

line are difficult to observe.

Thracia is reported from the early Mesozoic on to the 

Recent. The Tertiary species, like the Recent, are 

widely scattered, but individuals are rarely abundant. 

Many of the east coast American forms are associated 

with northern faunas.

Thracia conradi Couthouy

Plate 10, figure 4

1831. Thracia declivis Conrad, Am. marine conchology, No. 2, 

p. 44, pi. 9, fig. 2. Not Mya declivis Pennant, 1778.

1839. Thracia conradi Couthouy, Boston Jour. Nat. History, 

vol. 2, p. 153, pi. 42, fig. 2.

1869. Thracia conradi Couthouy, Am. Jour. Conchology, vol. 4, 

app. p. 54.

1870. Thracia conradi Couthouy. Gould, Invertebrata of Massachusetts, Binney ed., p. 69, fig. 384.

1889. Thracia, conradi Couthouy. Dall, U. S. Nat. Mus. Bull. 

37, p. 64, pi. 69, fig. 9.

1903. Thracia conradi Couthouy. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 6, p. 1524.

1904. (?) Thracia conradi Couthouy. Glenn, Maryland Geol. 

Survey, Miocene, p. 359, pi. 95, fig. 4.

1906. Thracia conradi Couthouy. Rogers, Shell book, p. 329, 

pi. 74, opp. p. 323, fig. 1.

1932. Thracia c<mradi Couthouy. Mansfield, Florida Geol. Survey Bull. 8, p. 72, pi. 14, fig. 11.

Shell transversely ovate, ventricose, very light, brittle, and 

thin, rather faintly diaphanous by reason of its want of thickness, subequilateral, slightly gaping at both extremities, inequivalve, the right valve being the more convex, its whole 

margin projecting considerably beyond that of the left; beaks 

proturberant, large, and cordiform, inclining a little backward, 

the summit of the right one excavated or emarginate to receive 

the opposing one; incremental striae numerous and distinct, 

occasionally forming feeble concentric ridges; the anterior portion of the shell is regularly rounded and its superior margins 

very thin; the posterior extremity is rather narrower and 

somewhat truncated, with an obtuse carination extending obliquely from the beaks to the angle of the basal 

and posterior margins; between this carination and the superior 

and posterior margins, the shell is slightly compressed. The 

basal margin is sinuous, curving outwardly in its central portion, corresponding to the most convex part of the shell. Ligamep* externally very prominent, and prolonged in a thin 

ruembrane the whole length of the corselet, which is strongly 

marked and extends from the beaks to the extremity; the internal portion of the ligament is attached to a strong, thick, 

nymphal callosity, projecting obliquely along the cardinal edge 

in each valve, wider toward the beaks, and having its surface 

but very slightly hollowed. Hinge destitute of a cardinal ossiculum. External color a pale ashy white, surface covered with 

a thin, light, cinereous epidermis, strongly adherent and forming 

numerous irregular, minute corrugations at the extremities, 

especially on the posterior one, but not shagreened as in T. 

corbuloides. Internal color a chalky white, not glossy, but 

somewhat inclining to nacre near the cardinal edge. Muscular 

impressions tolerably large, remote; the anterior narrow, 

elongated, contracted, and tapering to a point toward the hinge 

margin; the posterior subtriangular or pyriform; pallial impression very superficial like the others, with a profound, subangular 

excavation posteriorly.

Length 21%0, height 2%0, diameterl%0 inches. Inhabits probably the whole coast of New England.—Couthouy, 1839.

The individuals from Maryland are more compressed than either the. Tertiary representatives in the 

area to the south or the Recent form and should probably be excluded altogether from T. oonradi Couthouy 

s. s., although the material is too imperfect to serve 

as a foundation of a new species.

In the Choctawhatchee of Florida, Thracia conradi 

has been recognized from the upper part of the middle 

Miocene—the Area zone through the Ecphora zone.

Distribution: Virginia: Miocene, Yorktown formation, 5 

miles northeast of Smithfield, Isle of Wight County; % to % 

mile below Sycamore, Southampton County; 1^ miles north 

of Suffolk, Nansemond County.

North Carolina: Miocene, Yorktown formation, (?) 1 mile 

above Branches Bridge, and Branches Bridge over the Meherrin River, Northampton County; Watsons Mill on Kirbys 

Creek, 2% miles northwest of Murfreesboro, and 1% miles 

above Murfreesboro on the Meherrin River, Hertford County; 

Halifax (on Quankey Creek) and Palmyra Bluff (on the 

Roanoke River), Halifax County; % mile above Bells Bridge 

over the Tar River, Edgecombe County. Duplin marl, 1% 

miles northeast of Fairmont, Robeson County.

Outside distribution: Miocene, Calvert formation, Fairhaven, 

Lyons Creek, Plum Point, and Chesapeake Beach, Md. Choctawhatchee formation, northern Florida. Recent, Labrador to 

Cape Hatteras in 3 to 15 fathoms. Most abundant on sandy 

or gravelly bottoms in about 10 fathoms of water.

Thracia transversa H. C. Lea

Plate 10, figures 5-10

1846. Thracia transversa H. C. Lea, Am. Philos. Soc. Trans.,

new ser., vol. 9, p. 237, pi. 34, fig. 11. 

1863. Thracia? transversa H. C. Lea. Conrad, Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 572. 

1903. Thracia transversa H. C. Lea. Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1525.

Shell subelliptical, very inequilateral, acuminately rounded 

posteriorly, truncate anteriorly, subcompressed, thin, smooth 

centrally, striate posteriorly and anteriorly; umbonial slope 

rounded; basal margin curved; dorsal margin angular in the 

middle, posteriorly convex, anteriorly concave; beaks somewhat 

acute; nymphal callosity small, oblique. Diameter 0.10, length 

0.18, breadth 0.28 of an inch.

From the shape of the anterior margin, I conclude that the 

shell must have gaped considerably there, but as I have no pair 

of valves I cannot be certain. The sinus of the palleal impression is deep and near the anterior cicatrix. In this character it differs from the rest of the genus.

This is, I believe, the first Thracia found in our Tertiary 

deposits. Deshayes, in his tables, gives 4 as the number of 

European Tertiary species. The present one is the smallest 

of the genus.—H. C. Lea, 1846.

Figured specimens: Acad. Nat. Sci., Philadelphia 

1585; U. S. Nat. Mus. 325509.

Type locality: Petersburg, Ya.

Lea has confused the anterior and posterior ends of 

the shell. The posterior end is shorter and is squarely 

truncated.
44 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OP VIRGINIA AND NORTH CAROLINA

The true affinities of the small Thracias in our study 

collections are very puzzling. They occur in the Calvert, the St. Marys, the Yorktown, and the Waccamaw 

formations, and, though showing considerable variation among themselves, show no more perhaps than 

might be covered by a species in which the valves are 

unequal in size and convexity. They can be very 

closely matched among the young of Thracia truncata 

Mighels and Adams and of T. phasianella Lamarck— 

both of them Recent species in which the young vary 

rather widely. The Tertiary individuals are, however, fairly uniform in size, and none of them exceed 

10 millimeters in latitude. No trace of any larger 

forms except T. conradi Couthouy, a species with a 

rather shallow and angular pallial sinus, has been 

found.

T. maddelysensis n. sp. is relatively higher and 

shorter; the incrementals are strong and regular on 

the umbones that evanesce distally; in Lea's form the 

incremental sculpture is least feeble near the distal 

margins, particularly the posterior margin; the sinus 

of T. transversa, though almost equally profound and 

evenly rounded as that of T. maddelysensis, is decidedly less broad.

Distribution: Virginia: Miocene, Yorktown formation, (?) 

Yorktown, York County; Petersburg, Dinwiddie County; (?) 

Everets farm, Everets, and (?) 1% miles north of Suffolk, 

Isle of Wight County.

North Carolina: Miocene, Yorktown formation, half a mile 

above Bells Bridge, Edgecombe County. Pliocene, Waccamaw 

formation, (?) NeiUs Eddy Landing, Columbus County.

Thracia maddelysensis Gardner, n. sp.

Plate 10, figures 1, 2

Shell small, rather heavy, inflated, irregularly and 

transversely ovate, inequilateral, probably gaping posteriorly. Umbones tumid, rather prominent, the apices 

proximate and directed toward each other and situated 

about two-thirds of the distance across to the posterior 

margin. Lunule and escutcheon absent. Anterior end 

produced, broadly and evenly rounded; posterior end 

squarely truncate; dorsal slope very low; base line 

gently arcuate. Posterior area defined by an obtuse 

angulation extending from the umbones to the junction 

of the truncated posterior lateral margin and the base 

line. Incrementals close, strong, and regular in the 

umbonal region, becoming discontinuous and evanescent toward the margins. Ligament external, opisthodetic, mounted on delicate linear nymphs; valve 

fissured beneath the umbones, probably for the reception of the internal ligament; all traces of the lithodesma lost. Hinge edentulous; anterior margin raised, 

however, into a triangular toothlike process just in 

front of umbones. Adductor muscle impressions small 

and rather high, the anterior angular and irregular in 

outline, and posterior oval. Pallial line obscure.

Sinus very broad, semielliptical, projected forward 

almost to the median vertical. Inner margins entire.

Dimensions of holotype: Height 4.0 millimeters, 

width 5.0 millimeters, convexity 1.05 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325508.

Type locality: Maddelys Bluff, Southampton County, 

Va.

Except for its small size, this species shows no indication of being the young of a larger form. The shell 

is moderately heavy for the genus, and the character 

of the incremental sculpture suggests an adult rather 

than a young individual. It is very much higher, relatively, than Thracia transversa H. C. Lea and differs 

from T. conradi Couthouy, which it most closely 

resembles in general proportions, by the very broad, 

deep, and evenly rounded pallial sinus—a character 

which in the latter is angular and much more shallow.

The species is known only from a single right valve 

collected at Maddelys Bluff, on the Meherrin River.

Distribution: Virginia: Miocene, Yorktown formation, Maddelys Bluff on the Meherrin River, Southampton County.

Family PANDOBIDAE 

Genus PANDORA (Bruguiere) Lamarck

1798. Pandora Bruguiere, Tableau encyclope"dique et m&hodique, 

vol. 1, pi. 250, figs. a-c. (No text.)

1799. Pan&ora Lamarck, Prodrome d'une nouvelle classification 

des coquilles, Soc. histoire nat. Paris M6m., p. 88.

Type by monotypy: Tellina inaequivalvis Linnaeus. Recent 

from the Channel Islands to the Mediterranean.

The shells are highly nacreous, transversely elongate, 

and rather alate, inequivalve, and inequilateral. The 

right valve is flattened or even slightly concave; the 

left, rather convex. The flattened, erect beaks are set 

far forward, and the anterior extremity is usually 

broadly rounded. The posterior dorsal margin is, in 

many species, slightly concave, the arcuate base line 

curving winglike to meet it. A narrow posterior area 

cut off by a cordate rostrum is developed in both valves. 

There is no lunule, but the narrow escutcheon is well 

defined. A narrow cartilage extends obliquely downward and backward from the tips of the umbones and 

is lodged in a shallow groove with slightly raised margins. The lithodesma, developed in some but not in 

all groups of Pandora, is on the anterior side of the 

ligament. The teeth are crude and vary in number 

and position in different subgenera. The mantle is 

loosely attached to the inner surface so that the pallial 

line may be discontinuous. The margin of the convex 

left valve commonly extends beyond the slightly reflexed basal margin of the right valve, and there is a 

slight gape at the narrow truncated extremity of 

the posterior area. The adductor scars are small, 

distinct, and strongly dorsal in position.

The genus includes only about 20 Recent species, but 

these are distributed from the Arctic seas to the Indian
PART 1. PELECYPODA

Ocean. In time, the group extends backward to the 

Cretaceous.

Submenus KENNERLIA Carpenter 

1864. Kennerlia, Carpenter, Zool. Soc. London Proc., p. 602.

Type by subsequent designation (Stoliczka, India Geol. Survey Mem., Cretaceous fauna southern India, vol. 3, p. 61, 1871) : 

Pandora, (Kennerlia) bicarinata Carpenter, 1864=P<m<iora Mlirata Conrad, 1855. Forrester Island, Alaska, to Point Abreojos, 

Lower California.

The subgenus is characterized by the presence of a 

lithodesma and by the development of a radial lineation. The dentition does not vary greatly from that 

of Pandora s. s.

Pandora (Kennerlia) arenosa Conrad

Plate 10, figures 16, 19, 20

1834. Pandora arenosa Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 130. 

1838. Pandora arenosa Conrad, Fossils of the medial Tertiary

of the United States, p. 2, pi. 1, fig. 3. 

1846. Myodora arenosa Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 3, p. 21. 

1863. Pandorella arenosa Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 572. 

1867. Pandora arenosa Conrad, Am. Jour. Conchology, vol 3,

p. 269. 

1885. Pandora carollnensis Bush, Connecticut Acad. Sci. Trans.,

vol. 6, pt. 2, p. 474. 

1903. Pandora, (Kennerleyia) arenosa Conrad. Dall, Wagner

Free Inst Sci. Trans., vol. 3, pt. 6, p. 1518.

Shell elliptical; obtusely pointed behind; dorsal margin 

rectilinear, with a submarginal raised line passing from the 

beak to the extremity; anterior side short, margin rounded. 

Length two-thirds of an inch.

Locality, Yorktown, Va. * * * Compared with P. trilineata of Say, it is more elliptical, smaller, and the teeth are 

remarkably small.—Conrad, 1834.

Shell inequivalve, inequilateral, nacreous within. 

Outline irregularly elliptical. Width approximately 

double the height. Left valve convex. Right valve 

flattened or slightly concave. Umbones inconspicuous, 

slightly incurved, anterior. Lunule very small, linearlanceolate. Escutcheon sublinear, its outer margin 

strongly carinated. Anterior extremity broadly expanding in front of the lunule. Posterior dorsal 

margin subrectilinear. Strong submarginal carinae 

developed in both valves, slightly wider in the left 

than in the right valve. A very broad but shallow 

depression in front of the carina, which contracts the 

margin and gives to the posterior part of the shell 

an alar aspect. Base arcuate. Edge of flattened right 

valve turned backward at the margin in order to 

coincide with the incurved overlapping edge of the 

convex left valve. Surface sculptured with concentric 

growth lines that are strongest anteriorly and on the 

posterior rostrum. Anterior area—between one-quarter and one-third of the entire valve—differentiated 

in the right valve by the much stronger incremental

401033—43———4

sculpture and, in the left, by the. less feeble incrementals and the slight but abruptT depression, which is 

marked chiefly by a sharp break in the growth lines. 

Radial sculpture absent or obsolete in the convex 

valve; in the flattened right valve about 11 sharp, 

irregular, and often bifurcating sulci in the exterior 

prismatic layer, not radiating directly from the umbones but originating along the dorsal submargin as 

well, though largely obsolete on the dorsal half of the 

valve. Ligament and resilium internal, partly separated in the left valve by an incipient shelly ridge; 

resilial pit in left valve buttressed by a low laminar 

elevation along the dorsal half of its anterior margin. 

Hinge of right valve bearing 2 cardinals—a very prominent, roughly hatchet-shaped tooth, and behind it and 

on the other side of the resilial pit a less elevated, 

obliquely produced, inverted V-shaped ridge; dentition 

in the left valve reduced to a low laminar buttress on 

the anterior side of the resilial pit and, in adults, often 

confounded with it. Margin just in front of umbones 

strongly incurved and bearing a heavy flange. Adductor muscle impressions equal, irregularly rotund, 

well up toward the dorsal margin. Pallial line punctate, not sinuated, extending but little in front of the 

medial horizontal.

Pandora arenosa Conrad is the smallest representative of the genus within the area under discussion. 

It is lower both relatively and absolutely than other 

members of the subgenus, and it has a less concave, 

more nearly rectilinear, posterior, dorsal margin.

Dimensions of figured topotypes: Double valves, 

height 8.5,millimeters, width 16.6 millimeters, diameter 

3.2 millimeters. Left valve of another individual, 

height 8.0 millimeters, width 14.5 millimeters, diameter 

2.6 millimeters.

Figured topotypes from Yorktown, Va. (the right 

and left valves of one individual and the left valve of 

a second individual): U. S. Nat. Mus. 325505.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1 mile northeast of Suffolk, Nansemond 

County. Rare.

Outside distribution: Pliocene, Caloosahatchee marl, Shell 

Creek, Fla. Recent, Hatteras to Yucatan in 15 to 124 fathoms.

Pandora (Kennerlia) dalli Gardner, n. sp.

Plate 10, figures 21, 24, 26

Shell of medium size, inequivalve, inequilateral, 

rather strongly compressed, concavo-convex, slightly 

flexuous, alate. Umbones very low, inconspicuous, the 

apices perforate in the type, set about one-quarter of 

the length back from the anterior margin. Lunule 

not defined. Escutcheon linear-lanceolate, very much 

elongated, strongly rostrate on its outer margin. Anterior extremity broadly rounded. Posterior dorsal 

margin slightly concave. Ventral margin curved winglike from the arched anterior end up to the dorsal line.
46 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Submarginal posterior restrain very pronounced, 

slightly wider and less strongly angulated in the left 

valve than in the right, thrown into sharp relief in 

the latter by the broad depression in front of it. 

Anterior area not differentiated in the right valve; 

in the left it constitutes between one-quarter and onethird of the entire valve and is outlined by a very slight 

but abrupt depression, which is more pronounced ventrally, and by a sudden break in the direction of the 

growth lines. Incremental sculpture strongest on the 

anterior area and the posterior rostrum. Radial sculpture confined to external prismatic layer of the right 

valve, which is unfortunately badly decorticated. Ligament and resilium internal, attached in the right 

valve between the two cardinals; in the left, produced 

obliquely backward and largely concealed by the overhanging dorsal margin. Hinge of right valve bears 

a prominent hatchet-shaped process, and behind it, 

on the other side of the resilial pit, a somewhat lower, 

obliquely produced dental ridge; anterior edge of the 

resilial pit raised to form an amorphous denticle; 

anterior dorsal margin beveled in the right valve; in 

the left valve it is slightly convex on its outer border 

and modified into a conspicuous flange on its inner. 

Adductor muscle impressions slightly depressed—the 

posterior a little smaller and more rotund than the 

anterior. Pallial line obscure, not sinuous, punctate, 

about two-thirds the way down from the beaks toward 

the ventral margin.

Dimensions of holotype: Height 11.1 millimeters, 

width 19.8 millimeters, diameter 2.9 millimeters.

Holotype, the right and left valves of a single individual and paratype: U. S. Nat. Mus. 325503.

Type locality: One-quarter of a mile below Jones 

Point, Essex County, Va.

Pandora dalli n. sp. is most closely related to P. 

arenosa Conrad. It is larger, however, and more compressed, less strongly inequivalve, and relatively higher; 

the dorsal line is gently concave instead of subrectilinear, as in Conrad's species; the margin is not 

abruptly contracted in front of the keel; the muscle 

impressions are larger; and the pallial line is less 

distant from the ventral margin. From P. (Clidiophora) crassidens Conrad, which it most closely resembles in general outline, it is separated by the 

absence of a left anterior cardinal.

Distribution: Virginia: Miocene, St. Marys formation, a 

quarter of a mile below Jones Point, Essex County.

Pandora (Kennerlia) naviculoides Gardner, n. sp.

Plate 10, figures 22, 23

Only the left valve is known. Shell rather heavy, 

the valve strongly inflated, alar in outline; width 

roughly twice the height. Umbones set back from the 

anterior margin, about one-quarter of the total length, 

very low, perforate in the type; umbonal region incurved and flattened for some distance ventral to the 

apices. Lunule not developed. Escutcheon linearlanceolate, strongly angulated on its outer margin. 

Anterior end short, the dorsal margin sloping rather 

gently, the lateral margin obtusely truncate. Posterior 

dorsal margin concave and somewhat distorted. Ventral margin curved winglike to the posterior rostrum. 

Rostrum strongly defined by the sharpness of the angle 

and thrown into relief by the depression of the valve 

and the contraction of the margin in front of it. 

Anterior area differentiated only by a break in the 

growth lines. Incremental sculpture fine, irregular, 

with no conspicuous stages. Ligament and resilium 

internal; resilial pit cuneiform, obliquely produced 

posteriorly, and largely concealed by the overhanging 

escutcheon. No cardinals developed. Margin in front 

of umbones heavily calloused and bearing on the inner 

surface a heavy flange; convex and cordate on the outer 

surface and simulating a lunule. Anterior adductor 

muscle impression sunken, rotund, well up under the 

dorsal margin, and about halfway between the umbones 

and the anterior lateral margin; posterior adductor scar 

obscure, halfway down the posterior dorsal margin. 

Pallial characters obliterated.

Dimensions of holotype: Height 8.9 millimeters, 

width 16.6 millimeters, convexity 4.1 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325504.

Type locality: Neills Eddy Landing, Columbus 

County, N. C.

Pcmdora naviculoides n. sp. is the most convex of the 

Tertiary east coast species. P. arenosa Conrad, which 

most nearly approaches it in outline, is smaller and is 

not only much less scoop-shaped but also has a much 

straighter dorsal margin and a less conspicuous keel, 

The escutcheon does not overhang the cavity, as in the 

more inflated species, and a low but distinct cardinal 

tooth is developed near the anterior margin of the 

resilial pit.

Distribution: North Carolina: Plfocene, Waccamaw formation, Neills Eddy Landing, 3 miles north of Cronly, Columbus 

County. The type is unique.

Submenus CLIDIOPHORA Carpenter 

1864. Clidiophora Carpenter, Zool. Soc. London Proc., p. 596.

Type by original designation: Clidiophora clamculata Carpenter. Lower California to Panama.

The diagnostic feature of the group is the much 

produced posterior dental lamina, developed in both 

the right and the left valve. There is also a partial 

calcification of the cartilage. The shells are mostly 

of moderate size, relatively compressed, and rather 

short.

Pandora (Clidiophora) crassidens Conrad

Plate 10, figures 17, 18

1838. Pandora crassidens Conrad, Fossils of the medial Tertiary of the United States, p. 2, pi. 1, fig. 2.
PART 1. PELECYPODA •47

1863. Pandora, crassidens Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 572. 

1867. Cleidiophora crassa Conrad, Am. Jour. Conchology, vol.

3,.p. 269. (Lapsus.)

1903. Pandora (Clidiophora) crassidens Conrad. Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1519.

1904. Pandora (Clidiophora) crassidens Conrad. Glenn, Maryland Geol. Survey, Miocene, p. 357, pi. 95, figs. 1, 2.

1932. Pandora (Clidiophora) crassidens Conrad. Mansfield, 

Florida Geol. Survey Bull. 8, p. 73, pi. 12, figs. 4, 7.

Shell perlaceous, concentrically wrinkled*; the large valve 

extending much beyond the posterior base of the lesser; anterior side very short, margin widely subtruncate; posterior obtusely rounded inferiorly, terminating above in a very short 

and obtuse rostrum; dorsal submargin of the larger valve with 

2 approximate carinae; lesser valve with only one distinct 

carina placed very near the margin; anterior cardinal tooth 

of the larger valve very long, thick, and slightly oblique, the 

posterior one very near the dorsal line, sulcate or fossetshaped; the middle one short and linear; in the flat valve, 

two oblique, very thick and prominent teeth, anterior to which 

is a shallow groove, bounded anteriorly by a rudimentary linear 

tooth; muscular impressions impressed; pallial impression 

punctate.

Locality, James River, near Smithfield, Va.

This species is very rare; I formerly referred it to the recent 

P. trilineata, but it differs greatly in the teeth and also in 

having the valves very unequal, the superior valve being slightly 

concave and the lower half of the inferior valve inflated, giving 

it a capacious interior. Say remarks of the trilineata that there 

is not much difference in the convexity of the valves.—Conrad, 

1838.

Conrad has apparently considered the raised margin 

of the resilial pit as the left posterior cardinal. The 

young of P. crassid/e-ns are relatively lower and more 

alate in outline than the adults. They are not, however, so slender and winglike as in P. tuomeyi, nor are 

they so thin or so compact in texture. The tendency 

toward an impressed radial striation in the right valve 

is very much stronger in the P. crassidens s. s. and'constitutes one of the best criteria for the separation of the 

young of the species from the very similar adults of the 

subspecies. The subspecies prodromos is shorter and 

more quadrate than crassidens s. s., with a more concave 

dorsal margin and more of a flip to the posterior dorsal 

extremity.

P. crassidens is rare in the Ecphora zone of the Choctawhatchee formation in Florida.

Distribution: Virginia: Miocene, Yorktown formation, 5 miles 

northeast of Smithfield and at Smithfield, Isle of Wight County; 

Sycamore, Southampton County; 1% miles northeast of Suffolk 

and 1 mile northeast of Suffolk, Nansemond County.

North Carolina: Miocene, Yorktown formation, 6 to 7 miles 

below Rocky Mount, 15% miles above Bells Bridge, and % 

mile above Bells Bridge over the Tar River, Edgecombe County; 

6 miles below Greenville and 6% miles below Greenville (at 

Tafts Landing), Pitt County. Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear 'River, Bladen County.

Outside distribution: Miocene, St. Marys formation, Cove 

Point and St. Marys River, Md. Choctawhatchee formation, 

upper bed of Alum Bluff (on the Apalachicola River), Calhoun County, Fla.

Pandora (Clidiophora) crassidens majorina Gardner, n. subsp.

Plate 10, figures 25, 28

The shell attains a size double that of the average 

'Pandora crassidens; roughly rectangular in outline; 

the right valve flat, the left valve moderately compressed. TJmbones anterior, subterminal. Lunule absent. Escutcheon linear-lanceolate, wider in the left 

valve than in the right, strongly angulated on its outer 

border. Anterior margin of valve broadly rounded to 

subtruncate. Posterior lateral margin subtruncate, 

rounding evenly into the base. Dorsal margin slightly 

concave. Submarginal carina rather narrow, emphasized, particularly in the right valve, by the shallow 

sulcus below it and extending from the umbones to the 

posterior lateral margin. Differentiation of anterior 

area less feeble in left valve than in right; area marked 

by a change in the direction of the growth lines—most 

obvious in the contour of the base line—and by the 

abrupt obsolescence of the resting changes. External 

surface sculptured with fine, irregular, discontinuous, 

incrementals and, in the older forms, undulated by the 

pronounced resting stages; a radial sculpture of faintly 

impressed, more or less dendritic sulci developed in the 

external, prismatic layer of the right valve and sometimes discernible on eroded surfaces in the left. Ligament internal; lodged in the right valve between the 

middle and posterior cardinals; surface of attachment 

in the left valve bilobed, produced obliquely backward 

and more or less concealed by the overhanging dorsal 

margin. Dentition of right valve consists of a very 

heavy, hatchet-shaped, middle cardinal; a linear, anterior cardinal in front of it; and at an equal distance 

behind it, an obliquely produced, cuneiform cardinal. 

Dentition of left valve limited to an anterior dorsal 

process—heavy, rude, and expanded dorsally into a 

wide flange—and a low, sublinear, posterior process 

placed at the anterior edge of the resilial pit, and in 

the adults fused with it. Inner surface of anterior 

margin in front of the anterior cardinal usually planed 

off so that all the concentric layers that make up the 

shell are exposed. Adductor impressions sunken—the 

anterior subrotund and rather high, the posterior vertically elliptical and higher than the anterior. Pallial 

line punctate, only moderately distant from the base.

Dimensions of holotype: Height 37.8 millimeters, 

width 59.6 millimeters, semidiameter (left valve) 8.2 

millimeters.

Holotype, U. S. Nat. Mus. 325501; paratype, U. S. 

Nat. Mus. 325500.

Type locality: Holotype, Halifax on Quankey Creek, 

Halifax County, N. C.; paratype, Sycamore, Southampton County, Va.

Pandora crassidens majorina seems to be something 

more than merely the gerontic phase of P. crassidens 

Conrad. The diagnostic characters are the much
48 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OP VIRGINIA AND NORTH CAROLINA

heavier and larger shell and the conspicuous flange 

borne on the left anterior cardinal. The incipient 

flange in some individuals referable to P. crassidens 

s. s. and more frequently in the closely related Recent 

P. gouldiana Dall indicates that this character is not 

of specific value.

Distribution: Virginia: Miocene, Yorktown formation, Maddelys Bluff on the Meherrin River and Sycamore, Southampton 

County.

North Carolina: Miocene, Yorktown formation, Halifax on 

the Roanoke River, Halifax County; Shiloh Mills on the Tar 

River, Edgecombe County.

Pandora (Clidiophora) prodromes Gardner and Aldrich

Plate 11, figures 2, 3, 11, 12

1919. Pandora, (Clidiophora) prodromos Gardner and Aldrich, 

Acad. Nat. Sci. Philadelphia Proc., p. 44, pi. 4, figs. 

9, 11, 12, 14.

Shell of moderate dimensions, rather heavy, compressed, inequivalve, strongly inequilateral, subquadrate in outline. Umbones very low and inconspicuous, 

often perforate, strongly anterior. Lunule not devel-' 

oped. Escutcheon persists to the extremity of the 

posterior dorsal margin and is sublinear and sharply 

delimited. Anterior extremity broadly rounded. Posterior extremity quite squarely truncate. Dorsal margin feebly concave. Ventral margin broadly arcuate. 

Submarginal carina outlined in the right valve by a 

linear sulcus and in the left by a subacute ridge. Anterior area very obscurely differentiated, occupying 

approximately one-third of the entire valve. Radial 

sculpture not developed. Incremental sculpture somewhat undulatory on the early portion of the valve, 

laminar and crowded toward the ventral margin. 

Ligament internal; lodged in the right valve between 

the middle and posterior cardinals and, in the left 

valve, in a bilobed pit posteriorly produced along the 

dorsal margin. Hinge dentition robust; anterior cardinal of right valve almost entirely obsolete; middle 

cardinal elongate, rhombic, strongly and abruptly elevated. Posterior cardinal compressed, elongate-cuneate, wedging out dorsally. Anterior cardinal of left 

valve, which extends from the apex of the umbones to 

the anterior adductor scar, is uniformly elevated and 

widens slightly toward the umbones. Posterior cardinal linear, inconspicuous, outlining the anterior 

margin of the resilial pit. Adductor impressions small, 

slightly sunken, irregularly rotund, placed well up 

toward the dorsal margin. Pallial line punctate^ 

broadly arcuate, remote from ventral margin.

Dimensions of holotype: Height 21.0 millimeters, 

width 33.0 millimeters, diameter 6.0 millimeters.

Holotype, double valves of a single individual: U. S. 

Nat. Mus. 325499. -

Type locality: Yorktown, York County, Va. Yorktown formation.

The species was described in order to bring out the

close relationship that apparently exists between the 

Tertiary Pandoras of the east coast and those of 

the Recent. In the Recent the subgenus Clidiophora 

is represented south of the Hatteras axis by the delicate, alate little form, Pandora trilineata Say. The 

northern analog, P. gouldiana Dall, is larger, heavier, 

and rudely rectangular in outline. The differences between the northern and southern analogs have apparently been inherited from their Tertiary precursors, 

P., tuomeyi of the Duplin and Waccamaw faunas and 

P. prodromes of the Yorktown. P. prodromos is a 

little higher relatively than P. gouldiana Dall, and the 

posterior margin in it is not so sharply constricted 

below the submarginal keel. The dentition of the Tertiary species is very much heavier than that of the 

Recent. The middle and posterior cardinals of the 

right valve and the anterior cardinal of the left are, 

in P. gouldiana Dall, compressed into little more than 

linear ridges, whereas in P. prodromos they are decidedly heavy and robust. P. prodromos is neither so 

large nor so heavy, however, as the coexistent P. crassidens Conrad; it shows no trace of the linear radial 

sculpture that characterizes crassidens, and the dorsal 

portion of the anterior cardinal of its left valve is not 

expanded into a well-defined flange as in Conrad's 

species.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1% miles north of Suffolk, 1% miles east 

of Suffolk, 1 mile northeast of Suffolk, 1 mile west of Suffolk, 

and % mile below the waterworks dam at Suffolk, Nansemond 

County.

North Carolina: Miocene, Yorktown formation, Tar Ferry on 

Wiccacon Creek (opposite Harrellsville), Hertford County.

Collections: United States National Museum, Johns Hopkins 

University, and Academy of Natural Sciences of Philadelphia.

Pandora (Clidiophora) tuomeyi Gardner and Aldrich

, • Plate 10, figure 27; plate 11, figures 9, 10

1856. Pandora trilineata Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 76, pi. 20, fig. 13. Not P. 

trilineata Say, 1822.

1903. Pandora- (Clidiophora) trilineata Say (part). Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1519.

1919. Pandora (Clidiophora) tuomeyi Gardner and Aldrich, 

Acad. Nat. Sci. Philadelphia Proc., p. 45, pi. 4, figs. 8, 

10, 13.

Shell of medium size, rather thin, transversely alate 

in outline, slightly flexuous, compressed, inequivalve, 

but only to a slight degree; strongly inequilateral. 

Umbones very low, the apices usually perforate, 

strongly anterior but not terminal. Lunule absent. 

Escutcheon sublinear, almost as long as the posterior 

dorsal margin, strongly angulated on its outer border. 

Anterior end of valve rounded or obtusely pointed. 

Posterior dorsal margin gently concave; submarginal 

carinae very sharp, wider and more depressed posteriorly 

in the left valve than in the right. Ventral margin curved 

winglike from the anterior expansion to the posterior
PART 1. PELECYPODA 49

rostrum; margin in front of rostrum contracted in left 

valve by the anterostral depression. Right carina outlined by a linear suleus. Anterior area between onethird and one-half the entire valve, differentiated only 

in the left valve and then merely by a somewhat obsolete, linear sulcus, and by the abrupt upcurving of 

the growth lines toward the front. Incremental sculpture fine, irregular, often discontinuous, with no very 

pronounced resting stages. Radial sculpture usually 

absent even in the right valve. Ligament internal; 

lodged in the right valve between the middle and posterior cardinals and, in the left valve, in a bilobed pit, 

obliquely produced beneath the dorsal margin. Hinge 

dentition moderately robust; anterior cardinal of right 

valve obsolete; middle cardinal compressed, rhomboidal, 

or hatchet-shaped; posterior cardinal compressed, 

obliquely produced, often acutely pointed medially or 

ventrally; anterior cardinal of left valve a moderately 

prominent ridge of uniform elevation that extends 

from the umbones to a point just dorsal to the medial 

line of the anterior adductor; posterior tooth linear, 

inconspicuous, merely the upraised anterior margin of 

the resilial pit. Adductor muscle impressions slightly 

sunken, irregularly rotund. Pallial line punctate, nonsinuous, nearer the jbase anteriorly than posteriorly.

Dimensions of holotype, a left valve: Height 9.5 

millimeters^ width 21.0 millimeters, convexity 2.0 millimeters. Paratype, an incomplete right valve: Height 

11.0 millimeters, convexity 1.5 millimeters.

Holotype (a left valve) and paratype (an incomplete 

right valve): U. S. Nat. Mus. 325502.

Type locality: Walkers Bluff on the Cape Fear River, 

Bladen County, N. C.

Pandora tuomeyi is confused in the old collections 

with the Recent P. trilineata of Say, a rather smaller, 

relatively lower species, more tapering in outline posteriorly. The chief difference, however, is in the 

dentition. In general, the cardinals of the Recent 

species are more compressed, more produced, and more 

sharply cut; in particular, the inner surface of the right 

valve of the Tertiary form, in front of the middle 

cardinal, is not thickened but is often feebly channeled; 

the middle cardinal is hatchet-shaped or rhomboidal 

and is shorter than the elevated laminar tooth of P. 

trilineata; the posterior cardinal is shorter, heavier, and 

less uniform in elevation, and the inequality between 

the two right cardinals is much more marked in the 

fossil than in the Recent species. In the left valve the 

resilial pit in P. tuomeyi is broader and less produced, 

and the upraised anterior margin is shorter and less 

sharp; the left cardinal in P. trilineatd has strongly 

defined margins, bears a flange on the dorsal half of its 

inner surface, and terminates ventrally near the dorsal 

end of the anterior adductor impression; the anterior 

cardinal of P. tuomeyi, on the other hand, suggests 

much more strongly1 a kinship to the subgenus Kennerlia; its anterior limit is often ill defined, and the hiatus 

between such a tooth and the incurved and calloused 

inner surface of the anterior margins of Kennerlia is 

not great; the cardinal in P. tuomeyi, furthermore, is 

not expanded dorsally into a flange and is placed farther forward so that its ventral termination is at the 

medial line of the adductor impression.

The young of Pandora crassidens s. s., though similar 

in dentition, are relatively higher, less alate, heavier, 

and less compact in shell texture, and show a stronger 

tendency toward a radial sculpture in the right valve. 

The individual selected as the type is unusually wide.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1% miles north of Suffolk, 1% miles 

northeast of Suffolk, 1 mile northeast of Suffolk, 1 mile west 

of Suffolk, and % mile below the Suffolk waterworks dam, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, Tar Ferry on 

Wiccacon Creek (opposite Harrellsville) , Hertford County. 

Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear 

River, Bladen County.

Outside distribution: Miocene, Duplin marl, Darlington, 

Darlington County, S. C.

Pandora (Clidiophora) trilineata Say

Plate 11, figure 7

1822. Pandora trilineata Say, Acad. Nat. Sci. Philadelphia Jour.,

1st ser., vol. 2, p. 261. 

1830. Pandora trilineata Say, American conchology, pi. 2, and

unpaginated text. 

1842. Pandora trilineata Say. Conrad, Nat. Inst. Promotion Sci/

Proc., 2d Bull., p. 190. 

1886. Pandora (Clidiophora) trilineata Say. Dall, Harvard

Coll. Mus. Comp. Zoology Bull., vol. 12, p. 312. 

1886. Pandora (Clidiophora) floridana (Dall ms.). Dall, idem,

p. 312. 

1889. Pandora (Clidiophora) trilineata Say. Dall, U. S. Nat.

Mus. Bull. 37, p. 68.

1902. Pandora (Clidiophora) trilineata Say. Dall, U. S. Nat. 

Mus. Proc. 1264, vol. 24, p. 511, pi. 31, fig. 4.

1903. Pandora (Clidiophora) trilineata Say (part). Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1519. 

Not Pandora trilineata Say. Tuomey and Holmes, 1856. 

Not Pandora trilineata Say of New England authors 

to 1870=P. gouldiana Dall.

Shell white, subpellucid, concentrically wrinkled; hinge 

placed at the posterior slope, which is very abrupt, and forming 

a very considerably obtuse angle with the hinge margin; hinge 

margin concavely much arquated, the surface flattened, and 

bounded on its edges by two elevated approximate lines, originating at the beak and continued to, the tip, which is rostrated; 

rostrum ascending; a distinct, slightly impressed line originates 

at the beaks and passes to the middle of the basal margin; 

right valve a little convex; left valve flat.

Length %o inch, greatest breadth x%o inch.

Inhabits the American coast.

Cabinet of the Academy and Philadelphia Museum.

I first discovered a single valve of this curious shell several 

years ago at Great Egg Harbor, on the shores of New Jersey; 

'since which, I have found two or three others on the coast of 

Georgia and east Florida, so that it may be said to inhabit our 

whole southern and middle coast. The inner edge of the hinge 

margin of one valve closes over that of the other,—Say, 1823,
50 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA A1STD NORTH CAROLINA

Pandora trilineata Say has been reported from a 

number of localities in both the Duplin and the Waccamaw formations. All the Carolinian individuals examined, however, both in the material under study and 

in the available reference collections, show specific differences and have been assigned to P. crassidens and its 

subspecies tuomeyi.

Superfamily POKOMYACEA

Family VERTICORDIIDAE

Genus VERTICOKDIA (Searles Wood ms.) Sowerby

1844. Verticordia (Searles Wood ms.) Sowerby, Mineral conchology, vol. 7, pi. 639.

Type by monotypy: Verticordia carditfornis Sowerby. Pliocene (Coralline Crag) of Suffolk, England.

Shell nacreous, equivalve, usually though not always 

small, and suborbicular. Umbones subcentral or anterior, prominent, prosogyrate,' and often strongly involute. Lunule false, somewhat depressed. External 

sculpture strongly radial. Ligament submarginal, 

continued to apices of umbones; internal cartilage 

supported by lithodesma. Strong subumbonal cardinal 

usually present in the right valve. Posterior lateral 

developed in one group. Left valve often devoid of 

true teeth, sometimes developing a posterior lateral, 

more rarely a subumbonal cardinal; valvular margins 

somewhat modified to function as laterals. Adductor 

impressions small, often obscure. Pallial line simple 

or feebly sinuous. Inner margins denticulated by the 

radiating costae.

Verticordia has, as might be inferred, only a meager 

representation in the east coast Tertiary deposits. 

The genus is characteristically a deep-water form, one 

species occurring at a depth of almost 1,700 fathoms, 

whereas the Miocene and Pliocene of Virginia and 

North Carolina are essentially shallow-water deposits.

Subgenus TRIGONULINA D'Orbigny

1846. Trigonulina D'Orbigny, in De la Sagra, Histoire physique, 

politique et naturelle de rile de Cuba; Mollusques, 

vol. 2, p. 291. 

Type by monotypy: Trigonulina ornata D'Orbigny. Recent

in the West Indies.

Trigonulina is set apart from Verticordia s. s. by 

the less regularly spaced radials, the deeper lunule 

and ligament groove, and the greater development of 

the dental process in the right valve and of the dorsal 

lamina in the left.

Verticordia (Trigonulina) rogersi Gardner, n. sp.

Plate 10, figures 12, 13

Shell very small, moderately inflated, tranversely 

oval, inequilateral. Anterior end expanded in front 

of the lunule. Posterior a parabolic curve. Umbones 

subcentral, acute, prosogyrate. Lunule minute but 

deeply excavated.' External sculpture very conspicuous; 7 subequal, strongly elevated, moderately broad,

evenly rounded radials on the anterior and medial parts 

of the valve, separated mostly by narrower interspaces 

but tending to widen posteriorly; 2 similar radials on 

the posterior submargin separated by triple or quadruple interspaces from those in front of them; entire 

external surface sculptured with microscopic radial 

granulation. Ligament inset, linear, continued under 

the apices of the umbones. Subumbonal cardinal of 

right valve short, moderately stout. Right posterior 

margin grooved down to the median horizontal for 

the reception of the elongated, posterior lateral of the 

left valve. Hinge of left valve not definitely known, 

but bearing, in all probability, the normal Trigonulina 

dentition. Adductor impressions and pallial line obscure. Margins strongly denticulated by external 

costae.

Dimensions of holotype: Height 2.5 millimeters, 

width 2.8 millimeters, convexity 0.7 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325506.

Type locality: Three quarters of a mile northeast of 

Smithfield, Isle of Wight County, Va. , Verti&ordia rogersi n. sp. is differentiated from the 

entire group of forms closely allied to the V. emmonsi 

by its smaller size, its much more inflated valves, its 

transversely oval outline, and its relatively broad and 

rounded radials, which are separated by narrower 

interradials. The radials are, furthermore, less numerous than in V. emmonsi Conrad, though, unlike 

those of the latter, they corrugate the entire valve with 

the exception of a smooth area in front of the posterior 

submargin. The hinge is decidedly less vigorous than 

in the other Tertiary Trigonulinas, though the difference is of 'degree rather than of kind.

The species is known only from two right valves, 

both collected from the Yorktown marls along the 

James River, in Isle of Wight County.

The species was named in honor of W. B. Rogers, 

the eminent director of the Geological Survey of Virginia from 1835 to 1842 and one of the founders and 

the president of the Massachusetts Institute of Technology from 1862 until his death in 1882.

Distribution: Virginia: Miocene, Yorktown formation. % 

mile northeast of Smithfield (on Mrs. Chalmers' farm; type 

locality) and Benns Church, % mile from the old church, Isle 

of Wight County; 1 mile west of Suffolk, Nansemond County.

Verticordia (Trigonulina) emmonsii Conrad

Plate 10, figure 14

1858. Verticordia sp. Emmons, North Carolina Geol. Survey 

Kept., p. 286, fig. 206.

1862. Verticordia emmonsii Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, vol. 14, p. 289.

1863. Verticordia emmonsii, Conrad, idem, p. 579. 

1903. Verticordia (Trigonulina) emmonsii Conrad. Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1512.

Conrad gave no description but merely affixed a 

name to Emmons' unnamed figure.
PART 1. PELECYPODA 51

Shell with 9 anterior and 2 posterior widely separated ribs, 

the surface covered with a coarse granulation arranged in 

radial lines. Longitude 6.5, altitude 5.3, diameter 2.5 millimeters. The teeth are strong, and the sinuation of the pallial 

line [is] conspicuous though shallow.

This is the largest of the species of this division of the 

genus and with much the most conspicuous granulation. From 

the recent V. (T.) ornata Orbigny it is distinguished by its 

size and by the fact that the recent species has such minute 

granulation that it is difficult to make it out.—Ball, 1903.

Shell nacreous, small, compressed, subcircular, inequilateral. Umbones subcentral, the apices acute and 

prosogyrate. Margin directly in front of urnbones 

deeply excavated by false lunule. Escutcheon absent. 

Anterior end somewhat expanded. Posterior margin 

a parabolic curve from the umbones to the arcuate 

base. External sculpture conspicuous; nine subequal, 

strongly elevated, linear lirae radiating from the umbones to the anterior hemicircle in gentle curves, convex posteriorly; interradials no wider than the radials 

anteriorly, broadening to more than double their width 

toward the medial portion of the valve; a single 

isolated radial more feeble than any of those in front 

of it a little less than halfway between the median 

vertical and posterior margin; posterior submarginal 

radial of normal strength. Entire external surface 

covered with microscopic radial granulation; incrementals sometimes discernible on 'the summits of the 

costae. Ligament deeply inset, continued to the apices 

of the umbones. Right subumbonal cardinal moderately stout, tubercular; posterior dorsal margin sulcated almost to the base to receive the elongated lateral 

of the left valve; lunular margin of left valve thickened to function as a denticle; no left cardinal developed. Adductor impressions small. Pallial line conspicuously distant from margin; sinus very shallow. 

Margin strongly denticulated by external costae.

Dimensions of figured specimen: Height 6.0 millimeters, wi^th 6.8 millimeters.

Figured specimen, a right valve: U. S. Nat. Mus. 

145332.

Type locality: North Carolina.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, 1% miles north of Magnolia, Duplin County. Pliocene, 

Waccamaw formation, Wilmington, New Hanover County.

Outside distribution: Miocene, Duplin marl, 5 miles southeast 

of Mayesville, Sumter County, S. C. Pliocene, Caloosahatchee 

marl, Caloosahatchee River, Fla.

Verticordia (Trigonulina) chowanensis Gardner, n. sp.

Plate 10, figures 11, 15

Shell nacreous, obliquely elliptical, greatly compressed. Umbones subcentral, acute, prosogyrate; margin directly in front of umbones deeply excavated by 

false lunule. Escutcheon absent. Anterior end evenly 

expanded in front of lunule. Posterior end a parabolic curve from the umbones to the arcuate base. 

External sculpture radial, very conspicuous; nine

gently curved, narrow, much elevated costae on the 

anterior half of the valve; intercostal spaces fully 

twice the width of the costals except on the extreme 

anterior margin; 2 proximate radials, slightly less 

prominent than those in front of them, midway between the median vertical and posterior margin; posterior marginal and submarginal costae of normal 

strength; radial granulation and incrementals microscopic. Interior of only the right valve is known. 

Hinge similar to that of V. emmonsi Conrad—a deeply 

inset ligament continued to the apices of the umbones, 

a moderately stout subumbonal cardinal, a deeply 

grooved dorsal margin for the reception of the left 

lateral, and a lunular margin modified to assist in 

the dentition. Adductor muscle impressions small, 

rather obscure. Pallial line conspicuously distant from 

margin; feebly sinuated. Margins strongly denticulate.

Dimensions of holotype: Height 5.1 millimeters, 

width 5.6 millimeters, convexity, 1.0 millimeter.

Holotype, a right valve: U. S. Nat. Mus. 325507.

Type locality: Colerain Landing on the Chowan 

River, Bertie County, N. C. Yorktown formation. 

Only the type and topotypes are known.

Verticordia cJiowtmensis differs • from V. emmonsi 

Conrad in the more compressed, obliquely elliptical 

outline, the more uniform and somewhat closer spacing 

of the costae on the anterior half of the shell, the two 

ribs (instead of only a single rib) on the midposterior 

half, and the presence of both a marginal and a submarginal posterior rib. The group of forms closely 

allied to V. emmonsi Conrad is peculiar in that each 

locality exhibits a perfectly well defined local variation. The material is, unfortunately, so meager that 

it is difficult to know just how much value should be 

placed on these mutant characters. Until intergrading 

individuals have been reported, it seems better, however, to keep the forms quite distinct.

Order TELEODESMACEA 

Su'perfamily ASTARTACEA

Family ASTARTIDAE 

Genus ASTARTE Sowerby

1816. Astarte Sowerby, Mineral conchology of Great Britain, 

vol. 2, p. 85, pi. 137.

Type by original designation: Venus scotica Maton and Rackett = Pectunculus sulcatus Da Costa. Recent off the British 

coast.

Astarte symmetrica Conrad 

Plate 12, figures 1-4

1834. Astarte symmetrica, Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 134. 

1840. Astarte symmetrica Conrad, Fossils of the medial Tertiary

of the United States, p. 44, pi. 21, fig. 7. 

1863. Astarte symmetrica Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 578,
52 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1894. Astarte symmetrical, Conrad. Whitficld, U. S. Geol. Survey Mon. 24, p. 54, pi. 8, figs. 1, 2.

1903. Astarte symmetrica Conrad (part). Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 6, p. 1488.

1904. Astarte symmetrica Conrad. Glenn, Maryland Geol. Survey, Miocene, p. 352.

Shell subtriangular, convex, with concentric impressed lines 

or undulations; anterior, posterior, and basal margins regularly 

rounded; apex rather prominent, acute, nearly central; lunule 

concave, ovate-acute; cardinal teeth very prominent, striated; 

margin crenulated. Length three-quarters of an inch, height 

rather less.

Locality, Yorktown, Va.

This species may be distinguished from A. vicina Say by the 

lunule, which is much less excavated; and the shell is also 

less convex than in the latter species.—Conrad, 1834.

The outline is usually subrotund rather than subtriangular, and the valves are less convex than might be 

surmised from Conrad's unmodified adjectives. Both 

the lunule and the escutcheon are narrow and not very 

conspicuously defined. The teeth are normal for the 

genus—an obsolete anterior cardinal, a prominent, subtrigonal middle cardinal, and a laminar posterior cardinal in the right valve; a vigorous anterior, subequal 

middle, and an obsolete posterior cardinal in the left 

valve.

Astarte symmetrica Conrad is the most nearly discoidal of all the coexistent Astartes. A. coheni Conrad, 

which sometimes approaches it, is larger, relatively 

higher, as a rule, and exhibits narrower and more prominent umbones and a much more deeply channeled concentric grooving. A. arata Conrad, which has been 

erroneously used as a synonym of A. symmetrica, is 

decidedly higher, more convex, and sculptured with an 

irregular incremental undulation that is supplemented 

with faint but distinct secondary striations.

Distribution: Virginia: Miocene, Yorktown formation, City 

Point, Prince George County; Yorktown, York County; Petersburg, Dinwiddie County; a quarter of a mile north of Chuckatuck, Nansemond County.

North Carolina: Miocene, Yorktown formation, 2^ miles 

northwest of Murfreesboro, near Murfreesboro, and 1% miles 

above Murfreesboro on the, Meherrin River, Hertford County; 

Palmyra Bluff, Halifax County; 15% miles above Bells Bridge 

over the Tar River, Edgecombe County; 8 to 9 miles west of 

Greenville, Pitt County; 2 miles northeast of Lizzie, Greene 

County.

Astarte exaltata Conrad

Plate 12, figures 5-8

1841. Astarte exaltata Conrad, Acad. Nat. Sci. Philadelphia 

Proc., vol. 1, p. 29.

1842. Astarte exaltata Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 8, p. 185. 

1845. Astarte exaltata Conrad, Fossils of the medial Tertiary of

the United States, p. 66, pi. 37, fig. 6. 

1863. Astarte exaltata Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 578. 

1903. Astarte exaltata Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. J489,

1904. Astarte vicina Say (part). Glenn, Maryland Geol. Survey, Miocene p. 350.

Obovate, acute, convex; umbo sulcated; apex very prominent; 

lunule elongated and profound. Height and length equal, % 

inch.—Conrad, 1841.

Figured specimens, a right and left valve of different 

individuals, U. S. Nat. Mus. 325519.

Type locality: Calvert Cliffs, Md.

Shell rather small for the genus but conspicuously 

heavy. Outline high, rounded-trigonal, inflated. Anterior end concavo-convex, deeply excavated in the 

lunular region, sharply bowed from the lunule to the 

base. Posterior dorsal slope steep; lateral margin 

obscurely truncate. Ventral margin broadly arcuate medially; upturned distally. Umbones subcentral, elevated, rather narrow and somewhat gibbous, and very prominent—-the apices acute and prosogyrate. Lunule very wide and deeply sunken. 

Escutcheon also wide, clearly delimited, coincident in 

length With the dorsal margin. External surface quite 

strongly undulated from the umbones to the base; 

sculpture sharply defined only in the young and on the 

apices of the umbones. Ligament external, opisthodetic; nymph narrow, bordered dorsally by the angular, 

ligamentary groove. Hinge plate narrow. Dentition 

vigorous; anterior cardinal of right valve obsolete; 

middle cardinal robust, cuneiform; posterior cardinal 

thin and laminar. Anterior and middle cardinals of 

left valve divergent on each side of the profound -subumbonal socket—the anterior cardinal slightly the 

shorter and stouter of the two. Posterior cardinal of 

left valve obsolete or fuse,d with the ligamentary 

nymph. Muscle impressions distinct—the anterior subrotund or reniform, the posterior rudely quadrate. Pallial line entire. Inner margins strongly denticulated.

One of the best distinctions of Astarte exaltata Conrad is the character implied in its name. Its elevated 

umbones, together with the stoutness of 'the small 

valves, are usually sufficient to isolate the species. A. 

roanokensis Gardner, the only other form that equals 

it in the degree of elevation of the umbones, is decidedly 

larger and has more strongly arcuate basal and lateral 

margins and a less strongly undulated external surface. 

A. arata Conrad and the closely allied A. stephensoni 

Gardner are also larger, decidedly more oblique, and 

less profoundly excavated in the lunular region.

Distribution: Virginia: Miocene, Yorktown formation, mouth 

of Baileys Creek, Prince George County; Claremont Wharf, 

Schmidts Bluff, 8% miles below Claremont Wharf; and near 

the mouth of Sunken Marsh Creek, Surry County; Zuni, 6% 

miles below Zuni, and 7 to 7% miles below Zuni on the Blackwater River, Isle of Wight County.

North Carolina: Miocene, Yorktown formation, 1% to 2 miles 

above Branches Bridge over the Meherrin River, Northampton 

County.

Outside distribution: Miocene, Calvert formation, Maryland.
PART 1. PELECYPODA 53

Astarte coheni Conrad

Plate 12, figure 15

1840. Astarte coheni Conrad, Fossils of the medial Tertiary of

the United States, p. 43, pi. 21, fig. 5. 

1863. Astarte coheni Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, p. 57& 

1903. Astarte coheni Conrad (part). Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1489.

Shell suborbicular, thick, slightly ventricose, equilateral; 

disks with wide, angulated, somewhat regular undulations; 

posterior extremity obtusely rounded; beaks prominent, curved 

forward; lunule large, cordate, very profound; inner margin 

crenulated.

Locality, Lancaster County, Va.

This species was presented by Dr. Cohen, of Baltimore. The 

matrix is sand, mixed with a very large proportion of the 

green grains derived originally from the secondary Green-sand 

formation.—Conrad, 1840.

Astarte coheni Conrad is larger, relatively higher, 

and more evenly rounded than A. symmetric^ Conrad. 

Among the rest of the coexistent species of the group, 

it is remarkable for the rather compressed valves, the 

subcentral umbones, and the arcuate ventral and lateral 

margins. The lunule is only moderately wide and not 

at all "profound" in the sense in which the lunule of 

A. exaltata is profound. The concentric sulci are 

deeper, more sharply channeled, and more uniform 

over the surface of the disk than in any other member 

of this feebly sculptured group; and the sculpture, 

combined with an outline suggesting roughly the quadrant of a circle, forms the most valuable diagnostic 

of the species. The hinge is normal arid the inner 

margin crenate at the resting stages.

Distribution: Virginia: Miocene, Yorktown formation, Petersburg, Dinwiddie County; Cobham Bay, Surry County; 1 mile1 

north of Zuni, Isle of Wight County; Sycamore on the Nottoway River, and % to % mile below Sycamore, % to % mile 

above the lower Seaboard Railway bridge, and Maddelys Bluff 

on the Meherrin River, Southampton County; (?) 1 mile 

northeast of Suffolk and (?) the drainage ditch of the Norfolk 

& Western Railway just east of Jericho ditch, Nansemond 

County.

Astarte roanokensis Gardner, n. sp.

Plate 12, figures 9, 10

Shell large for the group, not very heavy, elevated 

and rounded, or somewhat obliquely trigonal in outline. Anterior margin concave in the lunular region, 

bowed outward in front of the lunule. Posterior dorsal slope very steep and usually exceeding half the 

total height. Lateral margin rounded or obscurely 

truncate. Basal margin feebly arched, upturned more 

strongly and evenly toward the anterior than toward 

the posterior end. Umbones subcentral, conspicuous 

by reason of their elevation, their apices acute and 

prosogyrate. Lunule smooth, rather wide, cordate, and 

excavated. Escutcheon relatively wide, clearly delimited. External sculpture very feeble, except at the

apices of the umbones, on which the concentric undulations are quite strong and regular. Apical sculpture 

quickly and abruptly replaced by the irregular and 

feeble undulation'due to the resting stages; a faint 

secondary striation usually introduced near the ventral margin in the adults; suggestions of faint radials 

often visible toward the posterior margin. Ligament 

marginal, opisthodetic; ligamentary nymph sublinear; 

groove behind it deep. Hinge plate narrow, trigonal. 

Dentition vigorous. The right valve has an obsolete 

anterior, a stout, trigonal middle, and a compressed 

posterior cardinal; the left v,alve, has subequal anterior 

and middle cardinals—the latter a little more compressed and produced—and a posterior cardinal fused 

with the ligamentary nymph; contiguous surfaces of 

cardinals transversely striate. Posterior dorsal margin 

of right valve and lunular margin of left beveled to 

function as laterals. Adductor muscle impressions distinct—the anterior oblong or slightly reniform, the 

posterior roughly quadrate. Pallial line entire. Inner 

margins crenate at the resting stages.

Dimensions of a cotype, a right valve: Height 24.4 

millimeters, width 23.9 millimeters, convexity 7.2 millimeters. Left valve of another individual: Height 24.2 

millimeters, width 23.9 millimeters, convexity 6.5 millimeters.

Type material: 2 cotypes, the right and left valves of 

different individuals: U. S. Nat Mus. 325523.

Type locality: Halifax, Halifax County, N. C.

Astart& roanokensis is remarkable for its narrow, 

prominent umbones, which, though they range in position from the median vertical to the anterior third, 

never lose their diagnostic beaklike aspect. The valves 

are more compressed and usually thinner than in any 

of the closely related, obliquely trigonal forms, such as 

A. stephensoni, n. sp. A. roanokensis occurs in the 

Yorktown marls along the Nottoway, Meherrin, Roanoke and Tar Rivers, but it is abundant only at the type 

locality—Halifax, on the Roanoke River, in Halifax 

County.

Distribution: Virginia: Miocene, Yorktown formation, Sycamore on the Nottoway River, % to % mile above the lower 

Seaboard Railway bridge over the Meherrin River, Southampton County.

North Carolina: Miocene, Yorktown formation, 1 mile above 

Branches Bridge, Northampton County; 1% miles above Murfreesboro, Hertford County; Halifax on Quankey Creek, Mr. 

Durham's farm, % mile above the Atlantic Coast Line Railroad 

bridge, and Palmyra Bluff, Halifax County; 15% miles above 

Bells Bridge and % mile above Bells Bridge over the Tar 

River, Edgecombe County.

Astarte hertfordensis Gardner, n. sp.

Plate 12, figures 11, 12, 21

Shell of medium size and thickness, moderately inflated, ovate-trigonal. Anterior end concavo-cbnvex. 

Posterior end obliquely produ'ced and narrowly 

rounded; basal margin feebly arcuate, more broadly
54 MOLLTTSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

and evenly upcurved anteriorly than posteriorly. Umbones prominent, set a little in front of the median line, 

flattened and pointed at the slightly prosogyrate 

apices. Lunule elongate-cordate, excavated, slightly 

wider in the left valve than in the right. Escutcheon lanceolate, slightly wider in the right valve 

than in the left. External surface smooth except for the 

concentric undulations of the apices, the irregular and 

rather ill-defined resting stages—most conspicuous, 

toward the anterior margin—the faint, discontinuous, 

concentric striations developed near the ventral and 

posterior margins, and a feeble suggestion of radials 

1 on the posterior half of the shell. Ligament marginal, 

opisthodetic; nymph linear; groove behind it sharply 

channeled. Hinge plate heavy. Dentition robust; 

anterior cardinal of right valve obsolete; middle cardinal stout, trigonal; posterior cardinal greatly compressed, almost laminar. Anterior cardinal of left 

valve cuneiform; middle cardinal slightly more produced and more compressed than the anterior and 

separated from it by a deep, triangular, subumbonal 

socket; posterior cardinal obsolete, fused with the 

ligamentary nymph; posterior dorsal margin of right 

valve and lunular margin of left beveled to function 

as laterals, and received by corresponding grooves in 

the opposite valve. Adductor impressions of medium 

size, largely below the median horizontal—the anterior 

oblong or slightly reniform, the posterior quadrate. 

Pedal adductor a small rotund depression just dorsal 

to the upper limit of the anterior adductor. Pallial 

line entire. Inner margins strongly crenate.

Dimensions of holotype (paired valves): Height 23.0 

millimeters, width 25.7 millimeters, diameter 14.4 millimeters.

Holotype: U. S. Nat. Mus. 325526.

Type locality: Murfreesboro, Hertford County, N. C.

Astarte h^rtfordensis s. s. is the most convex of all 

the obliquely trigonal Astartes of the region under 

discussion, except A. arata Conrad, a relatively higher 

and less inequilateral form. Its nearest relative is 

probably A. stephensoni Gardner, a less inflated and 

usually less solid shell, with more oblique umbones and, 

as a rule, noticeably more narrow in the umbonal 

region.

A. hertfordensis Gardner is apparently limited in 

distribution, for it has been found only in the Yorktown marls in the vicinity of Murf reesboro, in Hertford 

County.

Distribution: North Carolina: Miocene, Yorktown formation, 

Watsons Mill on Kirbys Creek, 2% miles northwest of 

Murfreesboro, and near Murfreesboro, Hertford County.

Astarte hertfordensis meherrinensis Gardner, n. subsp.

Plate 12, figure 18

Shell less inflated and usually less solid than that of 

Astarte hertfordensis s. s. Relative proportions somewhat variable but less so than in the type of the species.

A narrower lunule and escutcheon concomitant with 

the more compressed valve. Surface sculpture varies 

somewhat in the extent of the concentric undulations in 

the umbonal region and in the strength and uniformity 

of the resting stages. Hinge and adductor characters 

are normal for the species but vary slightly with the 

outline of the shell. '

Dimensions of the holotype: Height 23.0 millimeters, 

width 24.8 millimeters, convexity 6.3 millimetersHolotype, a right valve: U. S. Nat. Mus. 325531.

Type locality: Branches Bridge over the Meherrin 

River, Northampton County, N. C.

The peripheral individuals of this thinner, flatter, 

and usually higher subspecific type sometimes approach 

Astarte roanokensu on the one hand, and A. stephensoni on the other. The subspecies does not attain, however, the relative height of the form from the Roanoke 

River, nor are the umbones, ever so narrow or so 

hooked. It is usually a little heavier than A. 

stephensoni and less produced posteriorly, with wider 

and more nearly erect umbones. The secondary concentric striation is very faint and often obsolete altogether, whereas the posterior rays, which have not been 

noted in any of the A. stephensoni, are often quite 

distinct; the resting stages are also more uniform in 

A< hertfordensis meherrinensis. The subspecies occurs 

along the Meherrin River, in both Virginia and North 

Carolina.

Distribution: Virginia: Miocene, Yorktown formation, 12 to 

14 miles below Zuni on the Blackwater River, Isle of Wight 

County; Maddelys Bluff, 3 to 4 miles above the lower Seaboard Railway bridge, and % to % mile above the lower 

Seaboard Railway bridge over the Meherrin River, 

Southampton County.

North Carolina: Miocene, Yorktown formation. 1% miles 

above Branches Bridge, 1 mile above Branches Bridge, 

Branches Bridge, Northampton County; Watsons Mill on 

Kirbys Creek, 2% miles northwest of Murfreesboro, 1% miles 

northwest of Murfreesboro, 1 mile above Murfreesboro, and 

at Murfreesboro, Hertford County.

Astarte stephensoni Gardner, n. sp.

Plate 12, figures 16, 17

Shell of medium size, compressed, inequilateral, 

obliquely trigonal. Anterior end shorter than the 

posterior, concavo-convex in outline. Posterior end 

obliquely produced, rounded, or obscurely truncate 

laterally. Ventral margin feebly arcuate medially, 

gently upturned distally. Umbones rather narrow. 

Apices acute, anterior, prosogyrate. Lunule elongatecordate, smooth, sunken, moderately wide, slightly 

wider in the left valve than in the fight. Escutcheon 

lanceolate, slightly wider in the right valve than in 

the left. Surface sculpture well defined only on the 

apices of the umbones, which are deeply furrowed concentrically; resting stages usually 'indistinct and unequally spaced; a very fine and irregular secondary 

striation developed near the ventral margin. Liga-
PART 1. PELECYPODA 55

ment marginal, opisthodetic, mounted on a linear 

nymph bounded dorsally by an angular groove. 

Dentition normal. The right valve has an obsolete 

anterior cardinal, a stout, trigonal middle cardinal, 

and a laminar posterior cardinal; the left valve, a 

robust anterior cardinal, and, on the other side of the 

deep subumbonal socket, an almost equally strong and 

slightly more produced middle cardinal; left posterior 

cardinal fused with the ligamentary nymph. Adductor impressions usually distinct—the anterior 

obliquely oblong or somewhat reniform, the posterior 

roughly quadrate. Pedal scar a rotund depression just 

dorsal to the anterior adductor. Pallial line entire, 

inner margins crenate.

Dimensions of holotype: Height 22.7 millimeters, 

width 24.2 millimeters, convexity 6.3 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325528.

Type locality: Halifax on Quankey Creek, Halifax 

County, N. C.

Astarte stephensoni is characterized by the compressed valves, obliquely trigonal outline, obliquely 

directed umbones, and the faint but distinct secondary 

striation developed near the ventral margin. A. roanokensis Gardner is higher both relatively and absolutely, 

usually less inequilateral, and more strikingly narrow 

and excavated in the umbonal region. A. hertfordensis 

s. s. is characterized by the heavy, inflated valves, but 

the subspecies meherrinensis is often quite as compressed, though rarely so thin, as A. stephensoni. The 

latter is quite constantly more produced and more angular posteriorly, usually narrower toward the umbones, 

and less regularly (though more vigorously) sculptured. The resting stages, which in the species from 

the Meherrin River are almost always distinctly though 

not strongly defined and uniform in strength, are in A. 

stephensoni almost or altogether obsolete; the secondary 

striation, on the other hand, is characteristic of the 

latter, though not confined exclusively to it.

Certain higher, more rounded, and less inequilateral 

forms from the vicinity of Murfreesboro have been referred rather dubiously to this species. It is quite possible that they should be given subspecific or perhaps 

even higher rank, but the imperfect state of preservation of the material makes their exact relationship 

doubtful.

The species is named in honor of Dr. L. W. Stephenson of the Federal Geological Survey, who-stands alone 

in his detailed and general information on the Upper 

Cretaceous from Maryland to Texas.

It is remarkable that Astarte stephensoni, as well as 

the two forms to which it is most closely related, should, 

with the exception of a single occurrence, be confined 

to the Yorktown marls of southern Virginia and 

northern North Carolina.

Distribution: Virginia: Miocene, Yorktown formation, mouth 

of Baileys Creek near its confluence with the James River,

Prince George County; DelawareJPark, Delaware, and a quarter to half a mile below Sycamore on the Nottoway River, 

Southampton County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Murfreesboro on the Meherrin River, Hertford County; 

Halifax on the Roanoke River, Halifax County.

Astarte arata Conrad

Plate 12, figures 13, 14

1840. Astarte arata Conrad, Fossils of the medial Tertiary of

the United States, p. 42, pi. 20, fig. 8. 

1863. Astarte arata, Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, vol. 14, p. 577. 

1903. Astarte symmetrica Conrad (part). Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1488.

Shell ovate-trigonal, convex, with concentric scalariform 

sulci and fine intermediate striae; lunule very large, ovate, 

deeply concave; base very regularly arched; posterior extremity 

subtruncated; margin crenulated. 

Locality, near City Point, Va.; rare.—Conrad, 1840.

Shell heavy, relatively inflated, high, rounded, trigonal. Anterior end concavo-convexo. Posterior end 

with a steep dorsal slope and an obscure lateral trauncation. Base line evenly but not strongly arched. Umbones prominent, inflated; apices acute and prosogyrate. Lunule smooth, deeply sunken, elongate-cordate. 

Escutcheon clearly delimited, moderately wide, lanceolate. Surface sculptured with irregular, concentric 

undulations—strongest and most regular near the umbones, evanescent ventrally, particularly on the posterior half of the shell. Fine, irregular, discontinuous, 

concentric striations developed in the adults—most conspicuous near the basal and posterior margins. Ligament external; nymph narrow; ligamentary groove 

sharply channeled. Dentition vigorous. In the right 

valve an obsolete anterior cardinal, a stout, triangular 

middle cardinal, and a laminar posterior cardinal; in 

the left valve a robust, somewhat cuneiform anterior 

cardinal, a slightly more compressed middle cardinal, 

and an obsolete posterior cardinal; posterior margin of 

right valve and lunular edge of left valve modified to 

function as laterals. Muscle impressions distinct, more 

than half their area below the median horizontal. 

Anterior adductor ellipsoidal or slightly reniform; 

posterior, semielliptical to rudely quadrate. Pallial 

line entire. Inner margins crenate.

Astarte arata Conrad is heavier and higher, more 

triangular, and less rotund than A. symmetric^ Conrad, 

with which it has been rather unaccountably confused 

in the synomymies. The lunule is wider and more 

deeply sunken. The secondary concentric striation, 

which is apparently a constant character in A. arata,, 

has not been noted in any individuals of A. symmetrica.

The diagnostic features of Astarte arata Conrad are 

the high, inflated umbones, the irregular wrinkling of 

the external surface by the growth sculpture, and the 

very distinct secondary striation. The two species 

most readily confounded with it are A. stephensoni—a 

relatively lower and more compressed form—and A.
56 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

hertfordensis, n. sp., which is also lower and more 

feebly, though m'ore regularly sculptured.

Distribution: Virginia: Miocene, Yorktown formation, near 

the mouth of Baileys Creek, Prince George County; a quarter 

to half a mile below Sycamore on the Nottoway River, 

Southampton County.

' North Carolina: Miocene, Yorktown formation, Halifax on 

the Boanoke River, Halifax County.

Astarte berryi Gardner, n. sp.

Plate 12, figures 23, 24

Shell relatively large for the genus, thick and heavy, 

rather strongly inflated, particularly toward the apices 

of the umbones. Subrotund or transversely oblong. 

Posterior dorsal slope moderately steep, merging into 

the rounded or obscurely truncated lateral margin. 

Anterior end convex in the vicinity of the lunule, 

bowed out in front of the lunule. Base evenly and 

rather strongly arched. Umbones subcentral, often a 

little in front of the median line, moderately prominent ; apices acute, turned toward each other. Lunule 

strongly depressed, elongate-cordate. Escutcheon 

elongate-lanceolate, well defined by the angulation of 

the valve and by the abrupt weakening and change 

in direction of the growth lines- External surface 

sculptured near the apices of the umbones with strong, 

rather regular concentric furrows, which quickly 

broaden and flatten into ill-defined undulations that 

are most distinct near the anterior margin; secondary, 

irregular, concentric striations usually present; traces 

of obscure radials often faintly visible in front of the 

escutcheon. Ligament marginal, opisthodetic; nymph 

moderately robust; groove behind it deep and angular. 

Dentition vigorous. Anterior cardinal of right valve 

almost altogether obsolete; middle cardinal stout, 

cuneiform, its distal surfaces transversely striate; 

posterior cardinal laminar, often broken away. 

Anterior cardinal of left valve prominent, laterally 

sulcated, separated from the shorter and more compressed middle cardinal by the wide and deep subumbonal socket; posterior cardinal of left valve almost 

obsolete; posterior dorsal margin of right valve and 

anterior lunular margin of left valve beveled to function as laterals. Muscle impressions very distinct, extending but little above the median horizontal. 

Anterior impression elliptical or slightly reniform. 

Posterior irregularly oblong to subquadrate. Pedal 

impression an irregular rotund dent dorsal to the 

anterior adductor. Pallial line entire. Inner margins 

strongly crenate at the resting stages.

Dimensions of holotype: Height 25.0 millimeters,, 

width 27.2 millimeters, convexity 8.8 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325533-

Type locality: 2y2 miles northwest of Chocowinity, 

Beaufort County, N. C.

Astarte 'berryi is separated from the obliquely 

trigonal si, stephensoni and A. hertfordensis, with its

subspecies meherrinensis^ by the more rounded outline. 

The valves are also heavier and the umbones more inflated than in the majority of individuals referable to 

the latter group of species. In general outline A. 

'berryi suggests Conrad's A. coheni, though it differs 

conspicuously in its larger size, heavier and more inflated valves and umbones, and much less sharply 

defined and uniform concentric sculpture.

I am pleased to name this Astarte in honor of Dean 

Berry, of Johns Hopkins University, who, though best 

known for his paleobotanical studies on the Cretaceous 

and Tertiary of the east coast and the Gulf, has collected extensively and most effectively from the faunas 

of the eastern and southern Tertiary deposits.

A. berryi is most abundant in the Yorktown marls 

of Pitt and Beaufort Counties, N. C., particularly in 

the environs of Chocowinity, and in the Yorktown at 

Colerain Landing, on the Chowan EiverDistribution: Virginia: Miocene, Yorktown formation. % to 

% mile above the lower Seaboard Railway bridge over the 

Meherrin River, Southampton County; 1% . miles north of 

Suffolk, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Murf reesboro, Mount Pleasant Landing, Hertford County; 

Colerain Landing, Bertie County; 2 miles below Toddy Station, 2 miles southeast of Tugwell (on Jacobs Branch), 1% 

miles northeast of Farmville, 2% miles north of Standard, 2 

miles west of Greenville (on Harris Mill Run), 1^ miles west 

of Greenville (on Schoolhouse Branch), 9 to 10 miles south 

of Greenville, and 1 mile northwest of Galloway Crossroads, 

Pitt County; 2% miles northwest of Chocowinity, 1*4 miles 

northeast of Chocowinity, 1 mile northeast of Chocowinity, 

Beaufort County; 1 mile north of Castoria, Greene County.

Subgenus ASHTAROTHA Ball

1903 (July). AsMarotha Dall, U. S. Nat. Mus. Proc., vol. 26, 

p. 936.

Type by original designation: Astarte undulata Say. Miocene 

of the middle Atlantic seaboard.

Umbones concentrically sculptured and conspicuously flattened; disk smoother outside of the flattened area; otherwise 

like Astarte.—Dall, 1903.

Astarte (Ashtarotha) rappahannockensis Gardner, n. sp.

Plate 12, figures 19, 20

Shell moderately large, heavy, and convex for the 

section. Bounded trigonal, not strongly inequilateral. 

Anterior end slightly expanded in front of the lunule, 

rounding broadly and gently into the base. Posterior 

dorsal margin descends uniformly and rather rapidly 

from the umbones almost to the upcurved base line, 

Lateral margin very short, obscurely truncate. Base 

line arcuate. Umbones subcentral, moderately flattened, the apices acute and feebly prosogyrate. Lunule smooth, elongate-cordate, depressed. Escutcheon 

smooth, lanceolate, delimited by the posterior angulation. External sculpture confined to the flattened parts 

of the umbones, which are concentrically ridged with 

10 to 15 relatively fine, subequal, and sub-equispaced
PART 1. PEtECYPODA

elevations. Feeble incremental usually discernible on 

the anterior part of the shell and near the ventral margin. Ligament marginal, short, deeply inset. Hinge 

vigorous; anterior and posterior cardinals of right 

valve feeble or almost obsolete; middle cardinal stout, 

cuneiform, inserted in the deep subumbonal socket of 

the left valve between the strong, subequal, anterior and 

middle left cardinals; posterior left cardinal obsolete. 

Adductor muscle impressions distinct and submedial, 

the anterior slightly oval, the posterior irregularly 

quadrate. Pedal impression a small dent just dorsal 

to the anterior adductor. Pallial line distinct, more 

distant from the ventral margin anteriorly than posteriorly. Inner margins finely and rather feebly 

crenate at the resting stages, apparently smooth during 

the growing stages.

Dimensions of holotype: Height 25.8 millimeters, 

width 28.6 millimeters, convexity 7.2 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325527.

Type locality: Kappahannock Eiver Bluffs near 

Urbanna, Va.

Astarte rappahannockensis is probably the St. Marys 

descendent of the A. obruta Conrad of the lower part 

of the Chesapeake group. It differs in the relatively 

higher, heavier, more convex shell, the more nearly equilateral outline—owing to the less produced posterior 

end—and the finer, closer, and more uniform sculpturing on the umbones. It is separated from A. undulata 

Say, the only other coexistent member of the subgenus 

Ashtarotha, by the less conspicuously flattened umbones 

and by the uniform slope of the posterior dorsal 

margin.

The species is confined apparently to the drainage 

basin of the Kappahannock Eiver.

Distribution: Virginia: Miocene, St. Marys formation, % mile 

below Jones Point, Essex County; 2J/£ miles south of Farnham, at Union Mill, Richmond County; Urbanna, Middlesex 

County.

Astarte (Ashtarotha) griftonensis Gardner, n. sp.

Plate 12, figures 22, 28

Valves compressed, trigonal, subequilateral, suggesting rudely the quadrant of a circle. Anterior end 

feebly excavated in the lunular region, broadly and 

evenly arched in front of the lunule. Umborial angle 

only a little over 90°. Posterior dorsal slope approximately uniform although somewhat broken by the 

slight, almost imperceptible, forward bend of the umbones. Posterior lateral margin obscurely truncate, 

merging gradually into the broad arch of the base. 

Umbones subcentral, low, flattened, and with a tendency 

toward a forward twist. Apices acute and slightly 

prosogyrate. Lunule smooth, rather narrow, its length 

often not exceeding one-third of the total height of the 

valve, sharply defined by the angulation of its dorsal 

margin. Escutcheon also rather narrow and relatively

short. Umbonal region sculptured with 2 to 5 concentric undulations, which rapidly broaden and flatten 

away from the umbones and evanesce altogether halfway down to the ventral margin, leaving the gently 

convex surface smooth except for faint, linear, concentric striations. Ligament marginal, opisthodetic; 

groove behind the nymph angular and deeply channeled. Dentition vigorous and clean cut. Anterior 

cardinal of right valve obsolete; middle cardinal stout, 

cuneiform; posterior cardinal laminar, fused with the 

ligamentary nymph. Anterior and middle cardinals of 

left valve subequal, cuneiform, divergent on each side 

of the deep, subumbonal socket; posterior tooth obsolete; contiguous surfaces of all the cardinals transversely striate. Muscle impressions large, submedial; 

anterior slightly renif orm; posterior roughly quadrate. 

Pallial line entire, rather distant. Inner margins finely 

crenate.

Dimensions of holotype: Height, 23.8 millimeters^ 

width, 27.0 millimeters; convexity, 6.8 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325524.

Type locality: 2 miles east of Grifton, Pitt County, 

N. C.

Astarte griftonensis is remarkable for its regular and 

rounded outline and its low, broad, concentric undulations, very few in number and limited to the dorsal half 

of the valve. A. u/ndulata Say is usually heavier and 

more angular, the posterior dorsal slope is relatively 

longer and distinctly shouldered near the apices of the 

umbones, and the concentric undulations are more numerous, narrower, and much sharper. A. thisphUa 

Glenn is also distinctly shouldered and much more vigorously sculptured. A. rappahannockensis is more convex and is ornamented with an umbonal sculpture of 

10 to 15 subequal concentric lirae instead of the 2 to 5 

low rounded undulations that rapidly broaden away 

from the apices. A. obruta Conrad is a heavier and 

slightly more convex shell, with a more produced posterior dorsal margin; it differs, furthermore, in the 

flattening of the umbones, which are almost at right 

angles to the vertical plane instead of following the 

uniform curvature ,of the valve from the apices to the 

ventral margin, as in the A. griftonensis; the apical 

sculpture is much sharper in the Calvert species and 

usually more limited in extent and more abruptly 

evanescent.

The species is fairly abundant at the single locality at 

which it is represented, the Yorktown sands, 2 miles 

east of Grifton, in Pitt County, N. C.

Distribution: North Carolina: Miocene, Yorktown formation, 

2 miles east of Grifton (on the property of J. F. Brooks), Pitt 

County.

Astarte (Ashtarotha) undulata Say

Plate 12, figures 25, 31

1824. Astarte undulata Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. 150, pi. 9, fig. 5.
58 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1834. Astarte undulata Say. Conrad in Morton, Synopsis of

organic remains, App., p. 3. 

1840. Astarte undulata Say (part). Conrad, Fossils of the

medial Tertiary of the United States, p. 41, pi. 20, flg. 7;

pi. 21, fig. 4 (young excluded). 

1856. Astarte undulata, Say. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 70, pi. 20, figs. 1, 2. 

1858. Astarte undulata Say. Emmons, North Carolina Geol.

Survey Kept., p. 289, fig. 213.

1863. Astarte undulata Say. Conrad, Acad. Nat. Sci, Philadelphia Proc. for 1862, vol. 14, p. 578. 

1903. Astarte (Ashtarotlia) undulata Say (part). Ball, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1491.

Shells trigonate, umbones flattened, and with profound 

undulations; apices very acute.

Basal half of the shell coarsely wrinkled, the remaining 

half deeply, regularly, and widely undulated on the flattened 

umbo; lunule large, oblong, subovate, concave, separated from 

the disk, particularly near the beaks, by an acute angle; beaks 

prominent, approximate, acute, turned a little backward at 

tip; ligament margin "concave nearly to the basal angle, and 

separated from the disk, near the beaks, by an acute angle; 

ligament very short; teeth regularly crenated on each side; 

basal angles rounded; basal edge nearly rectilinear or very 

obtusely arcuated; within finely crenated; smaller muscular 

impression very distinct.

Length four-fifths of an inch, breadth rather less than ninetenths of an inch.

A very distinct species, unlike any other yet described. It 

varies in proportional length, some being longer than broad, 

and others broader than long.—Say, 1824.

Shell varies widely in relative proportions and thickness. Umbones central or slightly anterior, conspicuously flattened and bent forward, thus giving to 

the posterior margin a gibbous aspect that is very 

characteristic. Apices of umbones acute, proximate. 

Lunule and escutcheon always smooth and clearly defined but varying in width with the outline of the 

individual. External sculpture exceedingly inconstant 

in strength and character; a few sharp, constant concentric ridges on the umbones; ridges sometimes, as in 

Say's figured type, covering the entire valve to the 

ventral margin; more frequently broadening, flattening, and finally evanescing about halfway down the 

valve. Ligament marginal, mounted on a narrow, 

oblique nymph but little longer than the cardinals. 

Anterior cardinal of right valve almost obsolete; 

posterior cardinal very feeble; middle cardinal robust, 

cuneiform, inserted in the deep, subumbonal pit of the 

left valve between the vigorous anterior and middle 

left cardinals; posterior left cardinal obsolete. Muscle 

impressions distinct; anterior adductor oval or reniform; posterior, subquadrate; pedal an irregularly 

rotund dent just dorsal to the anterior adductor. 

Pallial line simple, distinct, distant from the base; 

inner margins finely crenate.

Type locality: "Maryland" (?).

This protean species is by far the most abundant of 

the genus in the Yorktown of Virginia and North 

Carolina. Its manifestations in outline and sculpture 

are so diverse that specific relationship between the

peripheral forms would not be surmised without the 

complete intergrading series, which establishes the consanguinity of the widely separated end members. The 

umbones constitute the most characteristic feature of 

the species. These are conspicuously flattened, strongly 

sculptured, and bent forward just ventral to the apices, 

so that they give to the posterior dorsal margin a 

diagnostic hunch.

The representatives of two of the most striking lines 

of variation have been isolated subspecifically.

Distribution: Virginia: Miocene, St. Marys formation, 2^ 

miles below Bayport and Urbanna, Rappahannock River, 

Middlesex County. Yorktown formation, Yorktown, York 

County; near the mouth of Baileys Creek, near its confluence with the James River, Prince George County; Lieutenant 

Run, Petersburg, Dinwiddie County; 5 miles northeast of 

Smithfield, 1% miles northeast of Smithfield, % mile northeast of Smithfield, % mile from Benns Church, 8 to 8% miles 

below Zuni, 12 to 14 miles below Zuni, Blackwater River, Isle 

of Wight County; Sycamore, % to % mile below Sycamore, on 

the Nottoway River, Maddelys Bluff, lower Seaboard Railway 

bridge, and % to % mile above the lower Seaboard Railway 

bridge over the Meherrin River, Southampton County; % mile 

north of Chuckatuck, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1^ to 2 miles 

above Branches Bridge, 1 mile above Branches Bridge, at 

Branches Bridge, Northampton County; 2% miles northwest 

of Murfreesboro, 1% miles above Murfreesboro, 1 mile above 

Murfreesboro, near Murfreesboro, 3 to 4 miles below Tar Ferry, 

Hertford County; Colerain Landing on the Chowan River, 

Bertie County; Halifax and Palmyra Bluff on* the Roanoke 

River, Halifax County; Swift Creek, 15% miles above Bells 

Bridge, % mile above Bells Bridge, % mile above Bells Bridge, 

1 mile above Bells Bridge, 1% miles above Bells Bridge over 

the Tar River, Shiloh Mills, and 1 mile below old Sparta Bridge, 

Edgecombe County; 2 miles below Toddy Station, 2 miles southeast of Tugwell (on Jacobs Branch), 1% miles northeast of 

Farmville, 3 miles south of Farmville, 2% miles north of 

Standard, 3 miles southwest of Frog Level (on J. A. Noble's 

branch), 8 to 9 miles west of Greenville (on the east side of 

Pinelog Branch), 3 miles west of Greenville (on Harris Mill 

Run), 2 miles west of Greenville, 1% miles west of Greenville 

(on Schoolhouse Branch), Greenville (just east of the country 

bridge), 8 to 9 miles southeast of Greenville, 9 to 10 miles south 

of Greenville, 1 mile northwest of Galloway Crossroads, and 3 

miles north of Grifton (on the property of James Dawson), 

Pitt County; 2% miles northwest of Chocowinity, 1*4 miles 

northeast of Chocowinity, 1 mile northeast of Chocowinity, 

Beaufort County; 3 miles east-southeast of Wilson, 1 mile 

northwest of Stantonsburg, Wilson County; 6 miles west of 

Goldsboro, Wayne County; 1 mile north of Castoria, half a 

mile east of Lizzie (on the property of David Summeril), 

Greene County; Rock Landing on the Neuse River, Craven 

County. Duplin marl, Lumberton (near the bottling works), 

Robeson County.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Duplin marl, Sumter district, S. C.; 

Porters Landing on the Savannah River, Effingham County, Ga.

Astarte (Ashtarotha) undulata vaginulata Dall

Plate 12, figures 26, 27

1903. Astarte undulata var. vaginulata Dall, Wagner Free Inst. 

Sci. Trans., vol. 3, pt. 6, p. 1491.

This differs from the typical undulata in being more triangular, with a straighter base, smaller, flattened area on the beaks,
PART 1. PELECYPObA 59

with finer concentric sulcation which extends in most specimens 

to the base of the shell, though somewhat irregularly.—Dall, 

1903.

Dimensions of lectotype: Height 22.4 millimeters, 

width 27.5 millimeters, convexity 8.3 millimeters.

Lectotype, a right valve: U. S. Nat. Mus. 146121.

Type locality: Grove Wharf on the James River, Va.

The subspecies is notably thick and convex, the posterior end more or less produced, the area behind the 

posterior keel abnormally wide, the escutcheon less 

clearly defined and occupying a smaller proportion of 

the entire posterior slope than in A. undulata s. s. The 

flattening of the umbones, which is made more prominent in vaginulata by the thickness and convexity of 

the shell, gives to the finely sculptured subspecies a 

transversely flexuous aspect that is distinct from the 

more angular contour of the normal compressed type 

with its sharp, concentric, umbonal ridges rapidly 

broadening ventrally.

Distribution: Virginia: Miocene, Yorktown formation, 3 miles 

northeast of Walkerton, Mattapony River, King and Queen 

County; Lanexa, New Kent County; Claremont Wharf, 

Schmidts Bluff, 8% miles below Claremont Wharf, James River, 

Surry County; 6% to 7 miles below Zuni, 7 to 7i/2 miles below 

Zuni, 8 to 8% miles below Zuni, 12 to 14 miles below Zuni on 

the Blackwater River, Isle of Wight County; Delaware on the 

Nottoway River and 3 to 4 miles above the lower Seaboard 

Railway bridge over the Meherrin River, Southampton County.

Astarte (Ashtarotha) undulata deltoidea Gardner, n. subsp.

Plate 12, figures 29, 30, 35, 36

1840. Astarte undulata Say var. Conrad, Fossils of the medial 

Tertiary of the United States, p. 41, pi. 21, fig. 4.

Shell heavy, conspicuously elevated. Umbonal angle 

as small as 30°. Posterior slope very steep, rounding 

rather abruptly into the rectilinear ventral margin. 

Anterior end very slightly expanded in front of the 

lunule, broadly and evenly arching into the .base. Umbones slightly anterior, flattened, and bent forward 

near the apices. Tips of umbones sculptured with a 

few sharp ridges, which rapidly broaden and flatten and 

become in some individuals altogether obsolete less than 

halfway down the valve. Hinge formula normal for 

the species but with the cardinals much more produced 

and relatively more slender.

Dimensions of holotype: Height 23.5 millimeters, 

width 24.7 millimeters, convexity 6.0 millimeters. Dimensions of paratype, an extreme individual: Height 

22.5 millimeters, width 19.0 ± millimeters, convexity 6.5 

millimeters.

Types: Holotype, a right valve: U. S. Nat. Mus. 

325525; paratype, a right valve: U. S. Nat. Mus. 325532.

Conrad's figured A. undulata Say var. was collected 

near City Point, on the James Elver, Va. The holotype 

is from 7 to 7% miles below Zuni; the paratype from 

Zuni, Isle of Wight County, Va.

The subspecies includes those A. undulata that are

remarkable for their high deltoid outline. They are 

further characterized, as a rule, by a heavier shell, and 

by broader, less numerous, and more rapidly evanescing 

concentric undulations.

Distribution: Virginia: Miocene, Yorktown formation, Indian 

Field Point, York County; mouth of Baileys Creek, Prince 

George County; Claremont Wharf, Schmidts Bluff, 8% miles 

below Claremont Wharf, Sunken Marsh Creek, and Cobham 

Bay on the James River, Surry County; Kings Mill, James 

City County; Fergusons Wharf, James River, 1 mile north of 

Zuni, Zuni (near the pumping station), 6% to 7 miles below 

Zuni, 7 to 7^ miles below Zuni, Blackwater River, Isle of Wight 

County; Delaware (on the Nottoway River) and Maddelys 

Bluff (on the Meherrin River), Southampton County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Murfreesiboro, 1 mile above Murfreesboro, and near 

Murfreesboro on the Meherrin River, Hertford County.

Astarte (Ashtarotha) concentrica Conrad

Plate 12, figure 32-34, 40

1834. Astarte concentrica, Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 133. 

1840. Astarte concentrica Conrad, Fossils of the medial

Tertiary of the United States, p. 44, pi. 21, fig. 6. 

1863. Astarte concentrica Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, vol. 14, p. 578. 

1903. Astarte (Ashtarotha) concentrica Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1492.

Shell subtriangular, compressed, with numerous concentric 

rounded costae, crowded on the basal margin; umbones slightly 

flattened; apex acute, central; lunule large, concave, lanceolate; 

posterior margin concave; submargin acutely angular, straight; 

extremity obtusely rounded; cardinal teeth strongly striated; 

margin crenulated. Length 1% inches, height % inch. 

Locality, Yorktown, Va.—Conrad, 1834.

Outline ovate-trigonal, compressed, inequilateral. 

Posterior end rounded. Anterior end expanded in 

front of the lunule, rounding broadly and evenly into 

the ventral margin. Umbones low, not conspicuous. 

Apices acute, feebly prosogyrate. Lunule smooth, 

sharply defined, narrow-elongate. Escutcheon lanceolate, about half the total height of the valve. Surface 

sculptured with 30 to 35 equal, concentric lirae, separated by linear interspaces; lirae mostly uniform and 

continuous across the disk, though tending to break up 

near the posterior margin. Ligament external; 

nymphs rather short and slender. Dentition robust; 

anterior cardinal of right valve feeble; middle cardinal 

cuneiform, strong, and prominent; posterior cardinal 

obliquely produced, compressed. Posterior cardinal of 

left valve obsolete; middle and anterior cardinals vigorous, diverging beneath the umbones. Inner margins 

of hinge teeth of both right and left valves transversely 

striated. Anterior lunular margin of right valve and 

posterior margin of left feebly sulcated to receive corresponding beveled edges of opposite valves. Adductor 

impressions rather large—the anterior oval or slightly 

reniform, the posterior semielliptical or rudely 

quadrate. Pallial line simple. Inner margins more 

or less strongly crenate.
60 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Astarte • concentric ffi Cdnrad is unique among its 

congeners in the possession of a lirate concentric 

sculpture that covers the entire valve. The species, 

which varies somewhat in outline and strength of 

sculpture, gives rise to Conrad's A. ~betta, an abnormally high type with an abnormally fine and close 

sculpture.

The form prevalent in the Duplin and Waccamaw 

formations seems also sufficiently distinct to be worthy 

of isolation, characterized as it is by a relatively low, 

heavy, and somewhat flexuous shell, with a more produced posterior end and a less uniform, concentric 

sculpture.

A. concentrica Conrad, though present throughout 

the Miocene and Pliocene of Virginia and North 

Carolina, is most abundant in the Yorktown formation.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown and 1% miles below Yorktown, York County; Petersburg, 

Dinwiddie County; 2 miles northwest of Smithfield, 1^ miles 

northeast of Smithfield, % mile northeast of Smithfield, % 

mile from Benns Church, and Everet's farm near Benns 

Church, Isle of Wight County; % mile north of Chuckatuck, 

1% miles southeast of Reids Ferry, 1% miles north of Suffolk, 

1% miles north of Suffolk, 1 mile northeast of Suffolk; % 

mile below the Suffolk waterworks dam, drainage ditch of 

the Norfolk & Western Railway just east of Jericho ditch, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, Tar Ferry 

on Wiccacon Creek (opposite Harrellsville), 1% miles below 

Tar Ferry, 3 to 4 miles below Tar Ferry, Dogwood Landing 

on the Chowan River, Mount Pleasant Landing, Hertford 

County; Colerain Landing and % to % mile above Edenhouse 

Point on the Ghowan River, Bertie County; Palmyra Bluff, 

Halifax County; 2^ miles northwest of Williamston (on the 

land of Joseph Cherry), 1 mile northwest of Williamston, 1 

mile southeast of Williamston, Martin County; 15% miles 

above Bells Bridge, % mile above Bells Bridge, % mile below 

Bells Bridge, 1 mile below Bells Bridge, Shiloh Mills, Tarboro, Tar River, Edgecombe County; 2 miles below Toddy 

Station, 2 miles southeast of Tugwell (on Jacobs Branch), 1*4 

miles northeast of Farmville, 2% miles north of Standard, 8 

to 9 miles west of Greenville (on the east side of Pinelog 

Branch), 3 miles west of Greenville (on Harris Mill Run), 2 

miles west of Greenville, 1% miles west of Greenville (on 

Schoolhouse Branch), 8 to 9 miles southeast of Greenville, 9 

to 10 miles south of Greenville, 3 miles north of Grifton (on 

James Dawson's farm), Pitt County; 2% miles northwest of 

Chocowinity, 1 mile northeast of Chocowinity, Beaufort County; 

1 mile west of Wilson (on Frank Barnes' land at Hominy 

Swamp), Wilson County; 1 mile east of Lizzie (on the land 

of T. N. Lassiter), Greene County. 2 miles southwest of Maple 

Cypress on the Neuse River, Rock Landing on the Neuse River, 

Craven Cou'nty. Duplin marl, 3 miles south of Clinton^ (on 

Gum Chimney Branch), 10 miles south of Clinton (on the 

property of J. N. Powell), Sampson County; Natural Well, 

1% miles north of Magnolia and Frank Wilson's and W. H. 

Kornegay's marl pits near Magnolia, Duplin County; 4 miles 

north of Lumberton (on the Berry Godwin plantation), 1 

mile west of Lumberton (on the property of Charles Rowland), 

Lumberton (near the bottling works), 2 miles below Lumberton, 

4 to 5 miles below Lumberton, Fairmont (Ashpole), 1% miles 

northeast of Fairmont (on the land of Andrew Jones), 4 miles 

northeast of Fairmont (at D. E. Lewis'), Robeson County. 

Pliocene, Waccamaw formation, Lake Waccamaw, Cape Fear

River, Bladen County; Neills Eddy Landing, 3 miles north of 

Cronly, Columbus County.

Outside distribution: Miocene, Duplin marl, Porters Landing on the Savannah River, Effingham County. Pliocene, Waccamaw formation, Nixons and Todds Ferry, Horry County, 

S. C.

Astarte (Ashtarotha) concentrica conradi Gardner, n. subsp.

Plate 12, figures 37, 41

Shell relatively small, low, heavy, and convex; 

slightly flexuous posteriorly. Anterior end more 

strongly produced and contracted than is normal for 

the species. Base line broadly arcuate. xUmbones set 

a little in front of the median line, slightly incurved 

and prosogyrate. Lunule elongate-cordate; both lunule 

and escutcheon relatively broad. Sculpture rather 

more elevated than in A. concentrica s. s., and less uniform. Dentition vigorous and clean-cut; transverse 

striations on the inner surfaces of the cardinals very 

distinct. Character of adductor impressions and pallial line normal. Inner margins finely crenate.

Dimensions of cotypes: Right valve, height 15.7 millimeters, width 19.0 millimeters, convexity 5.3 millimeters, left valve of another individual, height 16.8 

millimeters, width 21.3 millimeters, convexity 6.0 

millimeters.

Cotypes: U. S. Nat. Mus. 325530.

Type locality: 4 to 5 miles below Lumberton, Eobeson 

County, N. C.

Astarte concentrica conradi is remarkable for its relatively small, heavy shell, which is inflated anteriorly, 

slightly depressed, produced, and contracted posteriorly, 

and ornamented with rather coarse, crowded, concentric 

lirae that lack the uniformity normal to the species. 

The subspecies, though occurring at a few isolated 

localities in the St. Marys formation and north of the 

Hattaras axis, is particularly characteristic of the 

Duplin marl south of the Hattaras.

Distribution: Virginia: Miocene, St. Marys formation, a 

quarter of a mile below Jones Point on the Rappahannock 

River, Essex County. Rare.

North Carolina: Miocene, Yorktown formation, 9 to 10 miles 

south of Greenville, Pitt County. Duplin marl, 2% miles south 

of Clinton (on Gum Chimney Branch) and 4 miles south of 

Clinton, Sampson County; Natural Well, 1% miles north of 

Magnolia, and W. H. Kornegay's marl pit near Magnolia, Duplin 

County; 4 miles north of Lumberton ' (on the Berry Godwin 

plantation), 1 mile west of Lumberton (on the property of 

Charles Rowland), Lumberton (near the bottling works), 2 miles 

'below Lumberton, 4 to 5 miles below Lumberton, 1% miles northeast of Fairmont (on the land of Andrew Jones), and at Fairmont (Ashpole), Robeson County. Pliocene, Waccamaw formation, Lake Waccamaw and Neills Eddy Landing (3 miles north 

of Cronly), Columbus County.

Astarte (Ashtarotha) concentrica bella Conrad

Plate 12, figures 38, 39

1846. (?) Astarte lineolata H. C. Lea, Am. Philos. Soc. Trans.,

2d ser., vol. 9, p. 241, pi. 34, fig. 20. 

1856. Astarte concentrica Conrad. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 71, pi. 20,, fig. 3.
PART 1. PELECYPODA 61

1858. Astarte concentric® Conrad. Emmons, North Carolina

Geol. Survey Kept., p. 289, fig. 212. 

1863. Astarte lella Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, pp. 577, 585.

1863. (?) Astarte lineolata H. C. Lea. Conrad, idem, p. 578. 

1866. Astarte compsonema Conrad, Am. Jour. Conchology, vol.

2, p. 72, pi. 4, fig. 18. 

1903. Astarte concentrica var. ~bella Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1492.

Triangular, compressed; marked by very regular, closely 

arranged, fine, concentric lines.

A. concentrica Tuomey and Holmes (not Conrad), Pleiocene 

fossils of South Carolina, 71, 20, 3; Emmons, North Carolina 

Geol. Survey Kept. 289, 212.

Locality, Virginia. -

Differs from concentrica in being proportionally shorter and 

in its much finer and more regular lines.—Conrad, 1863.

The lineolata of H. C. Lea is a very young shell and 

is undeterminable, even specifically. The subspecies 

bella is separated from A. concentrica s. s. by its higher 

outline and by its finer, closer, and even more regular 

concentric sculpture—all of which characters are of little systematic importance in the Astartes. The form has 

a place in the literature, however, arid though rare is 

readily recognizable.

Distribution: Virginia: Miocene, Yorktown formation, 

Petersburg, Dinwiddie County.

' North Carolina: Miocene, Yorktown formation, Branches 

Bridge over the Meherrin River, Northampton County.

Outside distribution: Pliocene, Waccamaw formation, 

Waccamaw, S. C.

Family CRASSATELLITIDAE 

Genus CRASSATELLITES Kriiger

1799. Crassatella of authors, not Crassatella Lamarck (Soc.

histoire nat. Paris Mem., p. 85. Sole species, Mactra

cygnea Chemnitz). 

1823. Crassatellites Kriiger, Geschichte der Urwelt, vol. 2, p. 466.

Type by monotypy?: Crassatellites sinuatus Kriiger. Eocene 

of the Paris Basin.

Through the kindness of W. J. Fox, the assistant 

librarian and editor at the Academy of Natural 

Sciences in Philadelphia, I received the following copy 

of Kriiger's original description:

Crassatellites simiatus. Crassatelle bossue.

Mit sehr dicken Schaalen, tiefen Muskeleindrueken und 

einzelnen Querreifen, welche auf der Oberflache mit dem 

untern Rande der Schaalen gleichlaufen. Haiifig bei Grignon.

Dall, following Bronn, and many others including 

myself, following Dall, have considered Kriiger's C. 

sinuatus as synonymous with Crassatella gibbosula 

Lamarck. This doubtless arose from Deshayes' citation in 1824 of Crassatella ~bossue as Crassatella 

gibbosula Lamarck.

Stewart 86 indicated the difficulty in reconciling

36 Stewart, R. B., Gabb's California Cretaceous ahd Tertiary type Lamellibranchs: Acad. Nat. Sci Philadelphia, Special Pub. 3, p. 136, 1930.

401033—43———5

Kriiger's description of sinuatus with Lamarck's gibbosula and the much closer correspondence of that 

description to Lamarck's plumbea. From an examination of the descriptions of, Deshayes, 1860, and 

the illustrations of Cossmann and Pisarro, 1906, 

Stewart observed 8e that "of the eight species of 

*''Crassatella'' cited by Deshayes from Grignon, only one, 

^Crassatella plumbeaj corresponds to the meager description of ''Crassatellites .sinuatus^ " of Kriiger. This 

is doubtless true, though Deshayes included in his 

synonymy of Crassatella plumbea, Crassatella tumida, 

which Stewart has accepted as a distinct species and 

as the type of 'Crassatella Lamarck.

In our collections from Grignon the heavy shells 

labeled C. tumida Lamarck might well pass for the 

original of Kriiger's description. C. tumida Lamarck, 

1807, is considere'd synonomous with C'. gibba Lamarck, 

1801 (gibbosa Lamarck of Deshayes, 1860, by an error), 

and has been designated as the type of Crassatella. As 

the French bossue is a literal translation of the Latin 

gibba, it seems reasonable to suppose that Kriiger had 

before him an example of C. gibba Lamarck, 1801. 

His reason for selecting sinuatus as the specific name 

of his species is not obvious. It seems to have nothing 

to do with Crassatella sinuata Lamarck, 1818, from the 

environs of Bordeaux. If the description and situs of 

his species were not so closely in accord with the heavy 

crassatellids of the Paris Basin, it might be reasonably 

conjectured that Kriiger had two rather than a single 

species in mind and that Crassatellites sinuatus and 

Crassatelle bossue referred to different forms. Access 

to larger collections and knowledge of the relative 

abundance and distribution of the forms in question are 

necessary for an adequate identification of Kriiger's

type.

There is a conspicuous lack of uniformity in usage 

of the generic name to be given to the group under discussion. It is admitted by all workers that Crassat&lla Lamarck, 1799, was founded on a Mactra. The 

French school have retained Crassatella on the plea 

that Lamarck cited in 1801, under practically the same 

description, Crassatella gibba=Crassatella tumida 

Lamarck, 1807. The name Crassatellites is also in 

disfavor because Kriiger, like Schlotheim, used the 

suffix ites to indicate merely the occurrence of the given 

genus in the fossil state. There has been no uniformity 

in the acceptance or rejection of names so compounded. 

Cox 87 probably takes the most easily tenable position, 

in holding that "the adoption of Crassatellites seems, 

however, to be the easiest solution of the problem 

caused by Lamarck's inconsistency."

Shell slightly inequivalve, inequilateral, subquadrate 

or subtrigonal in outline. Umbones anterior and 

usually prominent. Lunule and escutcheon distinctly 

depressed. Surface sculpture concentric, usually feew Cox, L. R., India Geol. Surrey Mem., n. ser., vol. 15, p. 210, 1930.
62 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

ble, and commonly confined to the umbonal area. 

Ligament and resilium internal. Dentition vigorous; 

three cardinals in the right valve—the posterior frequently effaced by the resilium—and two in the left. 

Anterior margin of right valve and the posterior margin of the left grooved to receive the beveled edge of 

the opposite valve. Muscle scars distinct, impressed. 

Pallial sinus simple. Ventral inner margins dentate. 

The distribution of Crassatellites is without new 

stratigraphic significance. As the group was well established in the Seaboard and the Gulf Provinces in the 

Upper Cretaceous, there is no reason to doubt that the 

Tertiary represeneatives are autochthonous. The Recent forms are included in about 40 species, the majority 

tropical in habitat.

Genus CRASSINELLA Guppy

1874. Crassinella Guppy, Geol. Mag., new ser., dec. 2, vol. 1, 

p. 450.

1875. Crassinella Guppy, idem, vol. 2, p. 42.

Type by monotypy: Crassinella, martinicensis d'Orbigny= ? 

Thetis parva C. B. Adams. Eecent in the West Indies.

The genus is characterized by the small, trigonal, 

compressed outline; the acute, erect, or slightly opsthogyrate subcentral umbones; the internal ligament; the 

2 delicate cardinals in each valve; and some form of 

lateral armature. Although it has been commonly considered as a subgenus of Crassatellites, the characters 

that separate the 2 groups seem sufficiently important 

to be considered generic.

Crassinella lunulata (Conrad) Dall

Plate 19, figure 30

1834. Astarte lunulata Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 133. 

1840. Astarte lunulata Conrad, Fossils of the medial Tertiary

of the United Sates, p. 44, pi. 21, fig. 8. 

1856. Astarte lunulata Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 72, pi. 20, fig. 4. 

1858. Astarte lunulata Conrad (part). Holmes, Post-Pleiocene

fossils of South Carolina, p. 32, pi. 6, fig. 9. 

1863. Oouldia lunulata Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 578. 

1903. Crassatellites (Crassinella) lunulatus Conrad. Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1477, pi.

49, fig. 15. 

1932. Crassinella lunulata (Conrad). Mansfield, Florida Geol.

Survey Bull. 8, p. 82, pi. 15, fig. 6.

Shell small, triangular, compressed, with about 13 acute, 

concentric, prominent lines; anterior slope rectilinear, angular 

at the extremity; basal margin rounded; beaks central, apex 

acute; lunule much elongated. Length and height nearly 

equal, about a quarter of an inch. Locality, Suffolk, Va.— 

Conrad, 1834.

Shell minute, moderately compressed, cuneiform, 

subequilateral in the adult stages. Dorsal slopes steep, 

subequal, the posterior sometimes slightly concave and 

produced. Basal margin strongly arcuate, forming 

with the dorsal slopes a 30° to 45° segment. Umbones

acute, opisthogyrate, central or slightly anterior. Lunule and escutcheon sublinear, the latter slightly more 

expanded; both of them coextensive .with the dorsal 

margins; clearly defined by the angulation of the valve 

and the abrupt disappearance of the sculpture. Surface ornamentation of 11 to 15 equisized and eqiiispaced 

concentric folds, which are pinched into sharply elevated free lamellae toward the margins and often over 

the entire disk; feeble and irregular secondary concentric striations sometimes present; crowded radial striations also visible in well preserved individuals and 

under high magnification, least feeble on the 

dorsal slopes of the lamellae near the base. Ligament internal; resilial pit narrow, somewhat oblique. 

Dentition of right valve reduced to a couple of simple, 

compressed cardinals in front of the ligament pit; 

anterior dorsal margin feebly sulcated; posterior dorsal margin beveled to function as a lateral. Two 

cardinals present also in the left valve—the posterior 

nothing more than a low laminar ridge bordering the 

resilium, the anterior simple, obliquely produced, 

moderately robust. Anterior dorsal margin beveled and 

grooved slightly toward the ventral margin; posterior 

lateral lamina strongly developed, parallel to the dorsal 

margin throughout its length; more prominent near 

the ventral end. Adductor impressions small, often 

obscure, the anterior irregularly rotund, the posterior 

oval or slightly reniform. Pallial line entire, rather 

distant from the base. Inner margins simple.

Figured specimen, U. S. Nat. Mus. 6123, from the 

Natural Well, Duplin County, N. C. Height 5.9 millimeters, width 6.7 millimeters.

Crassinella lunulata (Conrad) exhibits within its 

narrow limits a wide range of variation. The characters are, on the whole, more stable in the fossil than 

in the Recent forms, though they are inconstant at all 

ages. The species varies in convexity, in thickness, in 

relative proportions, and in the curvature of the base 

line; the posterior dorsal slope may be oblique and similar to the anterior, or, as is frequently true of the 

young, it may be convex and more produced than the 

anterior. The variations in sculpture are the most 

obvious. The concentric sculpture, which is typically 

sharpest and strongest near the margins, broadens 

slightly and flattens medially; in many of the young, in 

a few of the adults, and in many of the senile forms 

the sculpture is either undeveloped or obsolete on the 

medial portion of the disk and usually less conspicuous 

anteriorly than posteriorly. This tendency is so extreme in some individuals that it has seemed wise to 

isolate them under the subspecies harrisi. In a few of 

the relatively higher and heavier forms, on the other 

hand, the laminae may number up to 18 or 20 and may 

persist with undiminished strength across the entire 

valve. The radial sculpture—supposed to have been 

developed only in the Recent representatives of the
PART 1. PELECYPODA 63

species—is discernible on the fossils also if the individual is sufficiently well preserved and the magnification sufficiently high.

The species is among the most abundant, the most 

widely distributed, and the most readily recognizable 

of all the minute bivalves. It is particularly prolific 

in the Yorktown along the York River, in Nansemond 

County in the environs of Suffolk, along the Chowan 

River, in Hertford and Bertie Counties, and in the 

Duplin and Waccamaw formations. It is recognized 

also in both the Area zone and the Cancellaria zone of 

the Choctawhatch.ee of Florida.

Distribution : Virginia : Miocene, Yorktown formation, 4 miles 

northeast of Walkerton on the Mattapony River, King and 

Queen County; % mile above Yorktown, Yorktown, 1^4 miles 

below Yorktown, and 2 miles below Yorktown, York County; 

old Claremont Wharf on the James River, Surry County; Lieutenant Run near Petersburg, Dinwiddie County; % mile northeast of Smithfield, Benns Church (14 mile from the old church), 

J. J. Everet's farm near Benns Church, % mile north of Zuni, 

and 12 to 14 miles below Zuni on the Blackwater River, Isle 

of Wight County; Maddelys Bluff, %' to % mile above the 

lower Seaboard Railway bridge, and 2y2 to 3 miles below the 

lower Seaboard Railway over the Meherrin River, Southampton 

County; y± mile north of Chuckatuck, iy2 miles southeast of 

Reids Ferry, Exit, 5% miles northwest of Suffolk, 2% miles 

northwest of Suffolk, iy2 miles north of Suffolk, 1% miles northwest of Suffolk, iy2 miles northeast of Suffolk, 1 mile east of 

Suffolk, 1 mile west of Suffolk, y2 mile below the Suffolk waterworks dam, and y2 mile, from the drainage ditch of the Norfolk & Western Railway just east of Jericho ditch, Nansemond 

County.

North Carolina: Miocene, Yorktown formation, iy2 miles above 

Branches Bridge and Branches Bridge, Northampton County; iy2 

miles above Murfreesboro, 1 mile above Murfreesboro, Tar Ferry 

on Wiccacon Creek (opposite Harrellsville), 1% miles below Tar 

Ferry, 3 to 4 miles below Tar Ferry, Dogwood Landing and 

Mount Pleasant Landing (on the Chowan River), Hertford 

County; Colerain Landing and % to % mile above Edenhouse 

Point, Bertie County; Palmyra Bluff, Halifax County; 15y2 

miles above Bells Bridge, 100 yards below Bells Bridge, % 

mile below Bells Bridge, 1 mile below Bells Bridge, Shiloh 

Mills, L. E. Fountain's farm at Tarboro, Tar River, Edgecombe County; 2 miles below Toddy Station, 3% miles northeast 

of Farmville, 3 miles south of Farmville, 2ys miles north of 

Standard, 8 to 9 miles west of Greenville (on the east side of 

Pinelog Branch), 8 to 9 miles southeast of Greenville, and 9 

to 10 miles south of Greenville, Pitt County; 1 mile west of 

Wilson (in Hominy Swamp, on the farm of Frank Barnes), 

Wilson County; 1 mile north of Castoria, % mile east of Lizzie 

(on the farm of David Summeril), 1 mile east of Lizzie (on 

the farm of T. N. Lassiter), Greene County; 2y2 miles northwest of Chocowinity, Beaufort County; 2 miles southwest of 

Maple Cypress, and Rock Landing, Craven County. Duplin 

marl, 2y2 miles south of Clinton (on Gum Chimney Branch, on 

the land of Hugh Moore), 10 miles south of Clinton (on the 

land of J. N. Powell), Sampson County; 1% miles north of 

Magnolia, at the Natural Well, and W. H. Kornegay's marl 

pit, Duplin County; Fairmont and 1% miles northeast of 

Fairmont (on the farm of Andrew Jones), Lumberton (near 

the bottling works), 2 miles below Lumberton, and 4 to 5 miles 

below Lumberton, Robeson County. Pliocene, Waccamaw 

formation, 4 miles south of Elizabethtown (on Hammond 

Creek, on the land of Mrs. Clark) and at Walkers Bluff on the 

Cape Fear River, Bladen County; Lake Waccamaw, Cronly

(ys mile east of the factories), and Neills Eddy Landing (3 

miles north of Cronly), Columbus County; Wilmington, New 

Hanover County.

Outside distribution: Miocene, Duplin marl, Darlington, 

Darlington County, S. C. Choctawhatchee formation, northern 

Florida. Pliocene, Waccamaw formation, Nixons and Todds 

Ferry, Horry County, S. C. Caloosahatchee marl, Caloosahatchee River, Shell Creek, and Alligator Creek, Fla. Croatan 

sand, Slocums Creek, Craven County, N. C. Pleistocene, (?) 

Labelle, Caloosahatchee River, Fla. (Vaughan).

Crassinella lunulata harrisi Gardner, n. subsp.

Plate 14, figure 45

1903. Crassatellites (Crassinella) 'galvestonensis Harris. Dall, 

Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1478, pi. 

49, fig. 14. Not Eriphyla, galvestonensis Harris, 1895.

Shell subject to the same variation in outline as that 

of Crassinella lunulata (Conrad) but generally higher 

and decidedly heavier. Umbones of the thicker forms 

flattened above. Subspecies based primarily on obsolete external sculpture; traces of low but regular concentric undulations, which are visible along the 

posterior dorsal margin and, more feebly, along the 

anterior, sometimes persist across the disk near the 

base, but are never pinched into free lamellae as in C. 

lunulata s. s. Hinge and pallial characters normal for 

the species.

Dimensions of holotype: Height 5.1 millimeters, 

width 5.2 millimeters.

Holotype, a left valve, U. S. Nat. Mus. 1630.

Type locality: Yorktown, Va.

The form figured by Dall in the Transactions of the 

Wagner Free Institute under the name C. galvestonensis may serve as a type for the subspecies. Harris' type 

from the Galveston well and all the individuals in the 

available reference collections are very young. They 

are, however, more heavy and rude in both outline and 

dentition than any of the young of C. lunulata in the 

extensive collections of east coast materials, and there 

are no intermediate forms to warrant their union with 

those from Yorktown. On the other hand, a complete 

intergrading series has been established that unites the 

forms in which the sculpture is quite obsolete—except 

along the posterior dorsal margin—with those in which 

the sharply elevated lamellae continue with undiminished strength from the posterior across to the anterior 

margin.

The tendency toward an evanescent sculpture, though 

widespread in time and space, is strongest in the Yorktown of Virginia, and all of the forms to which subspecific rank has been given are confined to that formation and area. In the Recent representatives, unlike 

those of the Tertiary, the sculpture often lingers longest 

near the umbones.

Distribution: Virginia: Miocene, Yorktown formation, % 

mile above Yorktown, Yorktown, and 1% miles below Yorktown, York County; */4 mile north of Chuckatuck, 1% miles 

southeast of Reids Ferry, 1 mile northeast of Suffolk, and % 

mile below the Suffolk waterworks dam, Nansemond County.
64 MOLLUSCA fROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Crassinella galvestonensis (Harris)

1895. Eriphyla galvestonensis Harris, Bull. Am. Paleontology, 

vol. 1, No. 3, pi. 1, figs. 2, 2a, 2b.

Form as indicated by the figures; hinge as in E. lunulata; 

exterior smooth, slightly undulating concentrically near the 

beaks; beaks, as in many species of Astarte and Crassatella, 

slightly flattened at the very apex but very gibbous just below.— 

Harris, 1895.

Locality: Galveston well, Texas, from 300 to 2,600 

feet.

No convincing evidence for the existence of the 

species from the Galveston well, in the east coast Tertiary deposits, has been presented. The forms figured 

under that name in the Wagner papers have proved to 

be a subspecies of Crassinella Iwiulata and have 

received the name harrisi.

Outside distribution: Miocene, Galveston well, Texas, 300 

feet to 2,600 feet.

Crassinella dupliniana Dall

Plate 13, figures 10, 11

1903. Crassatellites (Crassinella) duplinianus Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1478, pi. 50,

figs. 5, 6. 

1932. Crassinella dupliniana Dall. Mansfield, Florida Geol.

Survey Bull. 8, p. 83, pi. 15, fig. 9.

Shell small, subtriangular, solid, with markedly acute beaks, 

which incline backward; anterior slope convexly arcuate, long; 

posterior slope nearly a straight or slightly concave line, 

shorter; lunule and escutcheon extending the whole length of 

their respective slopes, long and narrow, the latter more excavated than the former and wider; both "are smooth; base 

arcuate; disk sculptured with rather close-set, regular, subequal, flattish, concentric ridges with narrower interspaces; 

these are sometimes feebly elevated but preserve their general 

close-set, regular character; hinge well developed, the posterior cardinal in the left valve often conspicuous. Height 3.2 

[3.1], breadth 3.2, diameter 1.7 millimeters.

This species is especially characterized by the closeness, 

regularity, and smoothness of its concentric ridges and the long 

and narrow luflule and escutcheon.—Dall, 1903.

Holotype (double valves) : U. S. Nat. Mus. 114922. 

Type locality: Natural Well, Duplin County, N. C. 

Mansfield reports the species from the Cancellcma 

zone of the Choctawhatchee formation of Florida.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, l1/^ miles north of Magnolia, and W. H. Kornegay's 

marl pit near Magnolia, Duplin County; 2 miles below Lumberton, Robeson County. Pliocene, Waccamaw formation, 4 

miles south of Elizabethtown (on Hammond Creek, on the 

property of Mrs. Clark), Bladen County; Neills Eddy Landing, 

3 miles north of Crouly, Columbus County.

Outside distribution: Miocene, Duplin marl, Porters Landing 

on the Savannah River, Effingham County, Ga. Pliocene, Waccamaw formation, Tillys Lake, Horry County, S. C.

Crassinella nansemondensis Gardner, n. sp.

Plate 13, figures 18, 27

Shell minute, compressed, ovate-trigonal, inequilateral. Posterior end somewhat shorter and more 

angular than the anterior; posterior dorsal slope steep,

its union with the arcuate ventral margin abrupt; 

anterior dorsal slope more gentle, rounding evenly into 

the base. Umbones low; apices acute, proximate, opisthogyrate. Lunule and escutcheon sublinear, coextensive with the dorsal margins, clearly defined by the 

angulation of the valves and the abrupt disappearance 

of the surface ornamentation. Sculpture of 15 to 20 

equal, continuous, concentric lirae, separated by linear 

interspaces. Dentition normal for the subgenus; resilial pit narrow, oblique; hinge of right valve armed 

with 2 simple, oblique, compressed cardinals, the 

posterior cardinal being stronger; posterior cardinal of 

left valve merely a low, laminar elevation bordering the 

resilium; anterior cardinal simple, comparatively 

robust; dorsal margins strongly modified to function 

as laterals; anterior dorsal margin of right valve feebly 

sulcated; posterior dorsal margin strongly beveled; 

anterior dorsal margin of left valve, beveled, the posterior lateral lamina strongly developed, parallel to 

the dorsal margin throughout its length. Adductor 

impressions rotund, submedial, often obscure. Pallial 

line entire. Inner margins simple.

Dimensions of types: Right valve (paralype), height 

2.7 millimeters, width 3.1 millimeters, sem diameter 0.5 

millimeter. Left valve of another individual (holotype), height 3.3 millimeters, width .3.5 millimeters, 

semidiameter 0.5 millimeter.

Types Holotype, U. S. Nat. Mus. 325534; paratype, 

U. S. Nat. Mus. 325515.

Type localities: Holotype, y2 mile below the Suffolk 

waterworks dam on the Nansemond River; paratype, 1% miles southeast of Reids Ferry, Nansemond 

County, Va.

Crassinella nansemondensis n. sp. of the Yorktowff 

fauna is the analog of C. dupliniana Dall'of the Duplin 

and Waccamaw faunas. The former is, however, a 

trifle less minute, decidedly more compressed, and 

more inequilateral than the southern species and shows 

less variation in the character and strength of the 

concentric sculpture.

Distribution: Virginia: Miocene, Yorktow,n formation, 1% 

miles southeast of Reids Ferry and % mile below the Suffolk 

waterworks dam, Nansemond County.

Superfamily CYRENACEA ,

Family CYEENIDAE 

Genus CORBICTJLA Megerle von Miihlfeldt

1811. Corbicula Megerle von Mtihlfeldt, Entwurf eines neuen 

Systems der Schalthiergehaiise, Magazin der Gesellschaft Naturforschender Freunde, 5ter Jahrgang, Berlin, p. 56.

Type by monotypy: Tellina fluminalis Miiller. Recent in the 

Euphrates River.

Shell usually heavy, subtrigonal or cordate; not 

markedly inequilateral. Umbones subcentral, high, 

and prominent. Lunule and escutcheon not defined. 

External surface smooth or concentrically furrowed.
PART 1. PELECYPODA 65

Epidermis polished. Cardinals 3 in each valve, diverging fanlike beneath the umbones. Both anterior and 

posterior laterals developed, finely striate transversely. 

Pallial line little or not at all sinuated.

Corbicula is abundantly represented in the nonmarine Cretaceous and Lower Tertiary deposits of the 

Western Interior, in a few restricted localities in the 

marine Tertiary of the east coast and Gulf, and in the 

Eocene of the Paris Basin. The Eecent species are 

confined exclusively to rivers and lakes of the Eastern 

World.

Corbicula densata (Conrad) Emmons 

Plate 15, figures 3, 4, 7, 8

1844. Cyrena densata, Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 1, p. 324. 

3545. Cyrena densata Conrad, Fossils of the medial Tertiary

of the United States, p. 68, pi. 39, fig. 2. 

1856. Cyrena densata Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 77, pi. 20, fig. 14. 

1858. Corbicula densata Conrad. Emmons, North Carolina Geol.

Survey Rept., p. 290, fig. 215A. 

1863. Corbicula densata Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 576. 

1865. Cyrena densata Conrad. Prime, Monograph Am. Corbiculadae, Smithsonian Misc. Coll., No. 145, p. 31. 

1903. Corbicula densata Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1450.

Subtriangular, thick, convex, with robust lines of growth; 

anterior margin obtusely rounded; basal margin profoundly 

and regularly curved to the posterior extremity, which is subtruncated, direct, and greatly above the line of the base; 

beaks central, summits elevated; teeth large, robust, very 

prominent, three in one valve and two in the opposite; middle 

tooth of the right valve bifid; lateral teeth elongated, robust; 

anterior tooth truncated, suddenly deflected at the extremity; 

posterior tooth distant. Length l1/^ inches, height 1% inches.

Locality, vicinity of Petersburg, Va.; Mr. Tuomey; rare.— 

Conrad, 1844.

Shell of medium size, rounded-trigonal to oblatespheroidal, strongly inflated in the umbonal region, 

subequilateral. Anterior end quite evenly rounded, 

nearly semielliptical. Posterior dorsal margin more 

oblique and more steeply descending than the anterior. 

Posterior slope more or less depressed, often obscurely 

carinated. Umbones strongly gibbous, involute, proximate, often very much eroded. Surface sculptured 

with fine, irregular, and discontinuous incrementals 

and stronger resting stages, many of which are only 

on the anterior half of the shell and become obsolete 

near the median vertical. Ligament marginal, 

opisthodetic, mounted on a short but conspicuously 

strong nymph. Three cardinals in each valve diverge 

fanlike beneath the umbones—the middle and posterior 

cardinals in the right valve and the anterior and 

middle cardinals in • the left valve robust, subequal, 

feebly sulcate; the middle cardinals somewhat stouter 

and more regularly sulcate than the distal; and the 

anterior cardinal of right valve and the posterior 

cardinal of the left very slender and laminar. Laterals

of the left valve sharply elevated, transversely striated, 

with gently arcuate ridges extending almost to the 

median horizontal and received between the double 

laterals of the right valve. Adductor impressions irregular, submedial. Pallial line entire, distant from 

the base.

This species, the only representative of the genus in 

the east coast Tertiary, is conspicuous for the symmetrical arrangement of the triple cardinals and the 

very strong, curved laterals.

Distribution: North Carolina: Miocene, Yorktown formation, 3 miles south of Farmville, Pitt County; 1 mile west of 

Wilson (in Hominy Swamp, on the property of Frank Barnes), 

Wilson County. Duplin marl, 2 miles below Lumberton, Robeson County. Pliocene, Waccamaw formation, Neills Eddy 

Landing (3 miles north of Cronly) and Lake Waccamaw, 

Columbus County; Wilmington, New .Hanover County.

Outside distribution: Miocene, Duplin marl, Darlington district, Darlington County, S. C. Pliocene, Waccamaw formation, Nixons, Horry County, S. C. Croatan. sand, Slocums 

Creek, Craven County, N. C.

Superfamily CYPRI1TACEA

Family EULOXIDAE 

Genus ETTLOXA Conrafl

1863. Euloxa Conrad, Acad. Nat Sci. Philadelphia Proc. for 

1862, pp. 578, 585.

Type by monotypy: Venus latisulcata Conrad. Miocene of 

Virginia.

Subtriangular, posteriorly sulcated; cardinal teeth three In 

the left valve, the two posterior teeth oblique; two teeth in 

the right valve, the posterior one oblique; sinus of pallial 

impression truncated or slightly emarginate posteriorly.—• 

Conrad, 1863.

Euloxa has been shuttled about from the Astartidae 

to the Veneridae and the Cyprinidae. It certainly is 

closer to the Astartes than to the venerids and probably closer to the cyprinoids than to the Astartes, The 

heavy chalky shell and the simple pallial line suggest 

Astarte and Corbicula. The definition of the lunule 

and escutcheon is less clear than that of Astarte but 

much more decided than that of Corbicula or the 

cyprinoids. The cardinal dentition approaches most 

closely that of the cyprinoids. The conspicuously 

heavy, trigonal cardinal is the middle cardinal of the 

left valve and not that of the right, as in Astarte. 

There is no trace of a lateral dentition. The cyprinoids 

include a number of genera of diverse characters and 

seem much less uniform in their development than the 

Astartes. The family apparently permits a wider 

variation within its ranks than that of the Astartes, 

and Eulooea has been left tentatively under that 

heterogeneous group.

Euloxa latisulcata (Conrad) Conrad

Plate 15, figures 1, 2

1840. Venus latisulcata Conrad, Fossils of the medial 

Tertiary of the United States, p. 40, pi. 20, fig. 6.
66 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1852. Astarte latisulcata D'Orbigny, Prodrome pale"ontologie,

vol. 3, p. 112, No. 2089. 

1863. Euloxa latisulcata Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, pp. 578, 5&x 

1872. Euloxa latisulcata Conrad, Acad. Nat. Sci. Philadelphia

Proc., p. 52, pi. 1, fig. 5. 

1903. Euloxa latisulcata Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1502.

Shell subtriangular, with coarse lines of growth and a few 

deeply impressed lines; posterior side with a wide concave 

furrow bounded by the umbonial slope, which is profoundly 

angulated; posterior extremity truncated obliquely inward, and 

emarginate; inferior angle slightly prominent; lunule large, 

ovate, not well defined; cardinal teeth thick and prominent.

Locality, Middlesex County, near Urbanna, Va.—Conrad, 

1840.

Shell heavy, porcellanous, subtriangular to subquadrate, convex, strongly inequilateral. Umbones 

strongly anterior, in some individuals set within the 

anterior sixth, their apices slightly flattened, acute, 

prosogyrate. Lunular area cordate, depressed, but not 

sharply delimited. Escutcheon outlined by an obtuse 

carina. Anterior end of valve slightly expanded in 

front of the lunule. Posterior dorsal margin oblique 

or subrectilinear. Lateral margin squarely truncate 

but contracted medially by the broad and deep gutter 

that depresses the valve from the umbones to the lateral 

margin—limited posteriorly by the fold that outlines 

the escutcheon, anteriorly by a more angular ridge that 

persists with uniform vigor from the umbones to the 

posterior ventral margin. Base line subrectilinear, 

feebly warped in front of the posterior keel. Surface 

sculptured only by incrementals, which are stronger 

and more crowded toward the ventral margin. Ligament external, opisthodetic, mounted on a narrow 

nymph a, little longer than the posterior cardinal. 

Hinge armature of right valve reduced to an isolated, 

sturdy middle cardinal and to an obliquely elongated 

and compressed posterior cardinal. Three unequal 

cardinals in the left valve—the anterior cardinal short, 

compressed, almost vertical; the middle stout, triangular, somewhat oblique; the posterior oblique, very 

slender, and elongate. Posterior dorsal margin of 

right valve slightly modified to fit into shallow sulcus 

of left valve; no true laterals developed. Anterior adductor impression semielliptical, more prominent than 

the irregularly quadrate posterior adductor. Pallial 

line simple. Inner margins entire.

Figured specimen, U. S. Nat. Mus. 214407, from the 

lower bed at old Claremont Wharf on the James Eiver, 

Va.; Height 20.0 millimeters, width 23.4 millimeters.

Until the discovery of two additional valves by Dr. 

L. W. Stephenson of the United States Geological 

Survey—one valve from the St. Marys formation of 

the Rappahannock River, the other from the James 

River—Conrad's type from the Rappahannock Riyer at 

Urbanna remained unique. The form is apparently

exceedingly rare, for it is not probable that a species 

of medium dimensions so strongly characterized would 

pass unnoted.

Distribution: Virginia: Miocene, St. Marys formation, 

Urbanna, Middlesex County (Conrad); half a mile below Jones 

Point on the Rappahannock River, Essex County; old Claremont Wharf on the James River. A single .valve has been 

collected at each of these three localities.

Family PLETTROPHORIDAE Dall 

Genus CORALLIOPHAGA de Blainville

1824. Coralliophaga de Blainville, Dictionnaire sci. nat, vol. 

32, p. 343.

Type by tautonomy: Coralliophaga coralliophaga Gmelin. 

Pliocene of Florida; Pleistocene and Recent of mid-America.

Shell thin, slightly gaping posteriorly. Outline irregular, very inequilateral, oblong, subcylindrical, often 

modiolariform. Umbones low, not far from the 

anterior margin. Surface smooth, radially or concentrically sculptured. Hinge with two very oblique 

cardinals, one of them bifid, and one posterior laminar 

lateral. Pallial sinus broad but shallow. <•

Coralliophaga, as may be inferred from the name, is 

a boring form inhabiting the hard parts of other 

organisms, especially corals and even rocks.

A number of species have been recorded from the 

Eocene; the Recent forms are mostly inhabitants of 

southern seas.

Coralliophaga? microreticulata Gardner, n. sp.

Plate 9, figures 2-6

Shell exceedingly thin, gaping posteriorly. Outline 

modiolariform. Umbones strongly anterior but not 

terminal; umbonal region sculptured with a fine microscopic reticulation, which becomes obsolete posteriorly. 

Posterior end irregularly corrugated by the incrementals. Hinge and pallial characters lost. Burrows 

funicular, averaging about 17.0 millimeters in maximum diameter and about 40.0 millimeters in length 

above the stem. Stem slightly constricted medially, 

suggesting in cross section a figure 8. Larger diameter, 

5 millimeters; smaller diameter, 2 millimeters. Matrix 

apparently a bryozoan colony.

Cotypes: U. S. Nat. Mus. 325560.

Type locality: Half a mile below the Suffolk waterworks dam, Nansemond County, Va.

Though the evidence at hand does not conclusively 

establish Coralliophaga in the east coast Tertiary, yet 

all the known facts indicate that microreticvlata should 

be referred to this genus. The shells are so thin and 

so much less resistant than the burrows to which they 

closely adhere that it was found impossible to extract 

even one of them in good condition. As the fragmentary nature of the types is due less to the want of 

material than to the mode of occurrence, it has seemed
PART 1. PELECYPODA 67

best to give the data already available, unsatisfactory 

and inconclusive though it may be.

Distribution: Virginia: Miocene, Yorktown formation, half 

a mile below the Suffolk waterworks tlam, Nansemond County.

Superfamily ISOCARDIACEA

Family ISOCARDIIDAE 

Genus ISOCARDIA Lamarck

1799. Isocardia Lamarck, Prodrome d'une nouvelle classification 

des coquilles, Soc. hist&ire nat. Paris M&n., p. 86.

Type by monotypy: Chama cor Linnaeus, 1767=<7fflreZwm humanum Linnaeus, 1758. Recent off the European coasts and 

fossil in the Pliocene and Pleistocene of the Celtic Province.

Shell equivalve, heavy, cordiform, inflated. Umbones 

distant, prominent, prosqgyrate. Lunule not clearly 

delimited. Surface smooth or concentrically furrowed; 

inner margins entire. Ligament entirely external, 

sunk in a deep groove. Teeth cyclodont; cardinals two 

in each valve, erect, lamelliform, .approximately parallel to the dorsal margin. Posterior lateral of left valve 

received in toothlike socket of right; anterior lateral 

rarely present. Adductor impressions subequal. 

Pallial line entire.

This genus of large, heavy, cordate shells originates 

apparently in the Jurassic. From that time on it has 

been represented, by a few conspicuous species. The 

Eecent species, including the type, are most abundant 

along the European shores.

Isocardia frateVna Say

, Plate 11, figure 15

1824. Isocardia fratema Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. 143, pi. 11, figs, la, Ib.

1838. Isocardia rustica Conrad (part), Fossils of the medial 

Tertiary of the United States, p. 20, pi. 11, fig. 1.

1852. Isocardia conradi D'Orbi|iiy\ Prodrome paleontologie, vol. 

3, p. 121.

1854. Glossus rusticus Sowerb^. Conrad, Acad. Nat. Sci. Philadelphia Proc., vol. 7, g. 29.

1863. Bucardia fraterna Say. Cjbnrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 576.

1900. Isocardia fraterna Say. Pall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, p. 1066.

Cordate-globose, slightly obliqtie, with rather large concentric 

wrinkles, and lines of growth; an elevated undulation on the 

anterior submargin, marking the greatest length of the shell; 

umbones not very prominent, ap£x rather suddenly incurved, 

acute; impressed space behind tlie beaks, dilated and rather 

profound; anterior tooth striated externally and placed on 

the middle of the anterior margin. Large specimen, greatest 

length (taken obliquely) 3% inches, breadth rather less.

Small specimen, greatest length rather over 1% inches, 

breadth nearly 1% inches.—Say, 1824.

Type locality: Maryland [ ?].

The umbones are anterior, the "impressed space behind the beaks" is the lunule, and the "anterior tooth" 

is the posterior lateral.

The shell is heavy, often massive, but rather crumbly; the valves vary somewhat in the relative proportions and in the degree of obliquity. The umbones are 

tumid, flattening near their tips, rather distant, strongly 

involute and prosogyrate. The depression in front of 

the posterior fold is usually, though not always, strong 

enough to undulate the shell from the umbones to the 

base. The growth lines are prominent and rather 

crowded toward the ventral margin. The opisthodetic 

ligament is deeply inset and the ligamentary nymph 

very heavy. The hinge is rude and massive; the two 

cardinals of the right valve are lamelliform and subequal, the ventral cardinal bem|* a little shorter, stouter, 

and more anterior than the dorsal. There are no right 

laterals, but a profound groove is placed about halfway 

down the posterior slope for the reception of the lateral 

of the opposite valve. The ventral cardinal of the left 

valve is stout and subconical, the dorsal very much compressed and elongated parallel to the arcuate dorsal 

margin; the posterior lateral is the solitary shelly peak, 

approximately midway between the umbones and the 

base. The muscle impressions are strongly defined, the 

posterior being much larger than the anterior; the pallial line connecting them is simple and moderately 

distant from the basal margin.

Distribution: Virginia: Miocene, St. Marys formation, Urbanna on the Rappahannock River, Middlesex County. Yorktown formation, Sunken Marsh Creek and Schmidts Bluff (8% 

miles below Claremont Wharf), Surry County.

Isocardia fraterna Carolina Dall

Plate 11, figure 5; plate 23, figure 39

1900. Isocardia Carolina Dall, Wagner Free Inst Sci. Trans., 

vol. 3, pt. 5, p. 1067, pi. 46, fig. 22.

Shell large, solid, rotund, rather thin for its size, with involute beaks, inflated and inequilateral valves; anterior end 

short, subangular above, rounding evenly into the base below; 

hinge line forms a segment of a circle; and, except the anterior 

angle, the outline of the valve is nearly suborbicular; near the 

umbo behind are traces of two radial ridges separated by a 

shallow sulcus, but these rapidly become obsolete and the 

surface of the valves smooth except fof incremental lines, which 

become stronger and more disposed in undulations near the 

anterior base in senile specimens; hinge normal, strong—the 

lateral smooth and well developed, the left cardinal duplex,' 

compressed, with a small deep pit for the opposite cardinal 

below the junction; anterior adductor scar small, impressed; 

posterior scar much larger. Longitude 95, altitude 92, 

diameter 74 millimeters.

This species is represented by two left valves in the 

National collection, obtained from North Carolina and Virginia. It forms a marked contrast to /. fraterna in its nearly 

smooth subglobular form and greater size. It may be that to 

specimens of this species Conrad referred when in his description of 7. rustica (=fraterna) he said that it "attains in 

North Carolina a larger size than the 7. cor with which 

Deshayes considers it identical." If Deshayes had specimens 

of this sort his conclusion would not seem so unreasonable as 

it does when one compares a good series of 7. fraterna with 

7. cor (=humana). The present species, though very much 

less ponderous than 7. fraterna, is thicker than 7. humana 

and has its hinge less compressed, especially the cardinals, of 

which the profile forms a broad M with a conical pit below 

it; the lateral is also stronger and proportionately more distant
68 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

from the cardinals; the posterior adductor scar is larger than 

in humana of the same dimensions, while the umbo of /. Carolina 

is smaller, more pointed, less involute, and is distant 6.5 millimeters from the hinge margin; while, in a specimen of J. 

humana slightly larger than that of /. Carolina, the umbo of 

the same valve is 18 millimeters from the margin. Correlatively, the excavation in front of the beaks is considerably 

smaller in /. Carolina. The largest senile specimens of /. 

humana are higher and less orbicular than the types of 

I Carolina, which are evidently senile specimens also. 1

On the whole, in spite of the fact that the material is scanty, 

there seems to be reason to think that in the Upper Miocene 

there is a type of Isocardia, leading from the older Miocene 

forms of Maryland in the direction of the /. humana of the 

European fauna.—Dall, 1900.

Holotype: U. S. Nat. Mus. 1657.

Type locality: Edgecombe County, N. C.

The type of Isocardia Carolina Dall is distinct from 

7. fratema Say. The shell of the former is much thinner and more evenly inflated; the flattening of the 

central umbones is less pronounced, and usually their 

tips are less strongly incurved; the posterior angulation 

is merely suggested and does not affect the contour of 

the shell, whereas in 7. fraterna not only the fold is 

clearly defined but the depression in front of it is 

usually strong enough to contract the base to a slight 

degree; the hinge is less robust, but the difference is 

no greater than normal for a form with a thinner shell.

The connecting series is so complete and so convincing, however, and the combination of characters so diverse, that the specific rank of 7. Carolina can scarcely 

be maintained. None of the supposedly diagnostic 

characters of the form are constant; individuals with 

heavy shells—presenting the typical outline of Say's 

species—attain a height of 87 millimeters, a length of 

113 millimeters, and a semidiameter of 44 millimeters; 

the outline varies from obliquely-ovate to subrotund to 

subquadrate; the shell may be thin or massive and, 

concomitant with the thinner shell, are less conspicuous 

incrementals.

Distribution: Virginia: Miocene, Yorktown formation (?), 

Grove Wharf, Surry County (U. S. National Museum) ; Delaware Park and Delaware, Southampton County.

North Carolina: Miocene, Yorktown formation, Murfreesboro, 

Hertford County. "Edgecombe County." C. Dall.

Isocardia fraterna glenni Gardner, n. subsp.

Plate 16, figures 1, 2

1904. Isocardia fraterna Say. Glenn, Maryland Geol. Survey,

Miocene, p. 317, pi. 85, figs. 3, 4. 

1909. Isocardia. fraterna Say, Grabau and Shimer, North

American index fossils, vol. 1, p. 561, fig. 770.

Specimens from Maryland are smaller and less rounded and 

have a more pronounced ridge and a basal angle where the 

dorsal and posterior slopes and margins meet. These differences seem constant but are not deemed of sufficient importance 

to justify separating the Maryland forms from those from 

Virginia.—Glenn, 1904.

Shell rather thin, crumbly. Valves rudely quadrate 

in outline; inflated anteriorly, somewhat depressed

posteriorly. Anterior lateral margin produced in front 

of the lunular area, broadly and evenly rounded or 

obscurely truncate. Posterior lateral margin also 

rounded to subtruncate along a line parallel to the 

vertical axis. Base line straight medially, upcurved 

laterally. Umbones strongly anterior, flattened on 

their summits, involute, and prosogyrate. Posterior 

carina clearly defined, so sharp dorsally that the umbones are distinctly angulated, becoming increasingly 

broader, lower, and more rounded ventrally, but persistent to the basal margin; a second-keel developed 

behind the carinal ridge but more feeble and usually 

evanescent about halfway down to the base. Valves 

slightly contracted in front of the posterior keel by a 

broad and very shallow depression. Lunular area 

strongly excavated but not sharply differentiated. 

Sculpture restricted to incrementals and, near the basal 

margin, to well defined and crowded resting stages. 

Ligament opisthodetic; ligamentary groove deeply 

channeled, undercutting the umbones to their very 

tips; nymphs heavy. Dentition rude. Two cardinals 

in each valve; those of the right valve lamelliform, the 

ventral cardinal a little sharper, more compressed 

laterally, and more anterior than the dorsal cardinal; 

groove between them profound. No true laterals in 

right valve; toothlike socket developed just dorsal to 

the posterior truncation. Cardinals of left valve unequal, the dorsal cardinal very much compressed and 

elongated parallel to the arcuate hinge margin, the 

ventral cardinal much shorter and less compressed. 

Adductor muscle impressions often obscure, the anterior 

sometimes sunken, rather small, and rudely semielliptical in outline; the posterior larger, more irregular and 

usually more obscure. Pallial line entire, and usually 

not very distinct.

Dimensions of holotype: Height 59 millimeters, 

width 73 millimeters, convexity 29 millimeters.

Holotype: Maryland Geological Survey, Johns Hopkins University, Baltimore, Md.

Type locality: Jones Wharf on the Patuxent,River, 

St. Marys County, Md. Choptank formation.

Isocardia fratema glenni is remarkable for its angular subquadrate outline, strongly defined posterior 

keel,, antecarinal undulation, and flattened umbones. 

It is not known to occur south of the Nomini Cliffs 

on the Potomac Eiver.

Superfamily CAEDITACEA

Family CAEDITIDAE 

Genus CARDITAMEBA Conrad

1838. Carditamera Conrad, Fossils of the medial Tertiary of the 

United States, p. 11.

Type by subsequent designation (Dall, Wagner Free Inst. 

Sci. Trans., vol. 3, pt. 6, p. 1408, 1903) : Cypricardia arata 

Conrad.

Shell equivalve, oblong; cardinal tooth in the right valve 

single, much elongated, compressed and nearly parallel with
PART 1. PELECYPODA 69

the basal margin; in the left valve 2, profoundly diverging, the 

posterior one corresponding with that in the opposite valve; 

lateral teeth two, distant, short, pyramidal; muscular impressions large; pallial impression entire.

The genus is nearly allied to Cypricardia but wants the 

three cardinal teeth and the long lateral tooth of that genus; 

from Cardita it is distinguished by the lateral teeth. The 

projection of the lunule in the right valve gives it the appearance of having two cardinal teeth. I know of this fossil species 

only, and a recent one nearly allied to it on the coast of 

Florida.—Conrad, 1838.

Superficially, Carditamera recalls some of the members of Mytilicardita Anton, notably Cardita variegata 

Brugui&re. Laterals are lacking in the Recent species, 

whereas in Carditamera the short remote anterior 

lateral of the left valve is well developed and is received within a clasping socket of the right valve, 

and a similar socket in the left valve receives the short 

but sharp posterior lateral of the right valve. In both 

the clasping sockets the inner margin is elevated and 

acute. Such a departure from the dentition of those 

groups that develop only cardinals is of generic value.

Carditamera arata verdevilla Gardner, n. subsp.

Plate 15, figures 5, 6

Shell compressed, strongly inequilateral, transversely 

oblong, broadly and feebly contracted medially. Umbones low, flattened on their summits, involute, slightly 

prosogyrate, only about one-fifth of the way back from 

the anterior margin. Approximately 15 radial costae, 

the 4 anterior ones rounded and closely, rather conspicuously imbricated; the medial costae low, broad, 

and flat, and even less affected by the incrementals 

than their subequal interspaces; the 2 costae that radiate from the umbones to the posterior ventral margin 

the most conspicuous on the valve, their summits 

strongly arched and coarsely imbricated; 2 smaller 

primaries and an adventitious secondary behind them. 

Hinge and pallial characters normal to the species and 

subgenus.

Dimensions of holotype: Height 22.3 millimeters, 

width 46.0 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325511.

Type locality: 8 to 9 miles south of Greenville, Pitt 

County, N. C.

The absence of concentric imbrications on the low, 

broad, medial costae strongly emphasizes the very 

feeble medial depression and, together with the relatively produced and compressed outline, suggests Cardita protracta Conrad rather than C. arata. The 

medial ribs of the former, however, are characteristically trigonal and often imbricated, whereas the summits of the latter are very low, very broad, and very 

flat, and destitute of sculpture. In the type, the concentric sculpture is abruptly discontinued on the fourth 

rib and abruptly reintroduced on the posterior half of 

the eleventh rib.

The type of the subspecies was collected a few miles

south of Greenville, where it occurs together with the 

normal C. arata (Conrad) and intergrading individuals. The young, which are rather abundant, are 

all normal. In Florida Carditamera arata occurs in 

the Cancellaria zone of the Choctawhatchee formation 

and possibly in the Ecphora zone.

Distribution: North Carolina: Miocene, Yorktown formation, 

8 to 9 miles southeast of Greenville, and 9 to 10 miles south 

of Greenville (on the property of Fred Haddock), Pitt 

County; Rock Landing on the Neuse River, Craven County.

Carditamera columbiana Gardner, n. sp.

Plate 15, figures 9, 10

Shell heavy, convex. Umbones broad, high, inflated, 

very much less strongly anterior than in C. arata. 

Kadial sculpture of 15 to 17 costae, their summits 

rounded, rather conspicuously imbricated, subequal in 

size and spacing, the ribs on the ill-defined posterior 

area slightly more narrow. Dentition normal for the 

genus in number and general arrangement but abnormally concentrated and equilateral, consequent on the 

outline of the valve.

Dimensions of holotype: Height 27.5 millimeters, 

width 37.0 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325510.

Type locality: Neills Eddy Landing on the Cape 

Fear Kiver, Columbus County, N. CThere is a strong tendency in the later and more 

southern members of this species toward a heavier, 

shorter, and much more convex shell, but it is not certain whether this is a variation that is due to age or 

to latitude. The type of the subspecies from the Waccamaw at Neills Eddy Landing is certainly very distinct from the individuals collected abundantly in 

Virginia, but the gradational series is so complete that 

there is no doubt about the true relations of the forms.

Carditamera colwrribiana may well be the precursor 

of C. tamiamiensis Mansfield, described from the early 

Pliocene of the Tamiami Trail, 42 miles west of Miami, 

Fla. It is a smaller shell, possibly a little higher relatively, with more elevated umbones and less prominent 

radials.

Distribution: North Carolina: Pliocene, Waccamaw formation, Neills Eddy Landing on the Cape Fear River (3 miles 

north of Cronly), Columbus County.

Genus GLANS Megerle von Miihlfeld

1811. Glans Megerle von Muhlfeld, Gesellschaft Naturforschender Freunde zu Berlin, Magazin fur die neuesten 

Entdeckungen in der gesammten Naturkunde, year 5, 

p. 68.

Type by monotypy: Chama trapezia Linnaeus. Recent in the 

Mediterranean.

Crlans s, s. differs from most of the other carditids 

by the small size, subquadrate outline, and the development of both anterior and posterior laterals.
70 MOLLTJSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Subgenus FLEUROMERIS Conrad 

1867. Pleuromeris Conrad, Am. Jour. Conchology, vol. 3, p. 12.

Type by monotypy: Pleuromeris decemcostata Conrad= 

Glans (Pleuromeris) tridentata (Say) var. decemcostata Conrad. Recent off the Florida coast; fossil in the Pliocene and 

Pleistocene of the southern Atlantic coast.

Equivalve, triangular, radiately ribbed; hinge in the right valve 

with one broad, nearly direct, concave or broadly furrowed 

recurved tooth, the upper extremity acute and opposite or above 

the apex of the shell; hinge in the left valve with three teeth, 

the anterior one small and fitting into a cavity in the opposite 

valve.—Conrad, 1867.

Also in the left valve is a short anterior lateral that 

is received within a double socket in the right valve; 

a very low posterior lateral in the right valve is received within a double socket in the left valve.

Pleuromeris is generically distinct from Cardita^ 

with which it has been commonly united. The type 

designation of Cardita has been the object of much discussion. Possibly the most comprehensive resume is 

that of Stewart.38 Stewart attributes Cardita to 

Bruguiere, 1792, and considers Cardita sylcata Brugu.ie>re=Chama antiquata Linnaeus, as the type of 

genus. The designation was made by Children, 1823. 

The small size and the development of a lateral dentition ally Pleuromeris with Glans rather than with 

Cardita.

Glans (Pleuromeris) tridentata (Say) Gardner

1826. Venericardia tridentata Say, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 5, p. 216. 

1832. Cardita Jridentata Say, American conchology, pi. 40,

figs. 1-5 with explanatory text. 

1858. Cardita tridentata Say. Holmes, Post-Pleiocene fossils

of South Carolina, p. 31, pi. 6, fig. 8.

1863. Actinobolus tridentata Say. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 578. \ 

1889. Cardita (Venericardia) tridentata Say. Dall, U. S. Nat.

Mus. Bull. 37, p. 46. 

1903. Venericardia (Pleuromeris) tridentata Say (part). Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1433. 

Not Cardita tridentata Reeve, 1843.

Shell suborbicular, subequilateral, thick, and ponderous, with 

about 18 convex longitudinal ribs cancellate by concentric elevated lines, which do not penetrate into the interstitial narrow 

spaces, and which are obsolete on the umbo and oh the anterior 

side; inner margin deeply crenate; hinge with 2 diverging 

teeth, separated by a large cavity on one valve, and on the other, 

a single large triangular prominent recurved tooth, closing 

into the cavity.

Length a quarter of an inch, breadth rather more.

This curious shell was discovered by Mr. Stephen Elliott on 

the coast of South Carolina. * * * This species will be regarded as an interesting addition to the fauna of the present 

world. The first recent species was described by Lamarck as 

a native of New Holland. All other known species are found 

only in the fossil state.—Say, 1826.

Shell rounded, trigonal, subequilateral, moderately 

convex. Anterior erid a little shorter, as a rule, and

38 Stewart, R. B., Gabb's California Cretaceous and Tertiary type 

Lamellibranclis: Acad. Nat. Sci. Philadelphia, Special Pub. 3, p. 149,1930.

more evenly rounded. Posterior dorsal margin 

obliquely truncate, merging inf eriorly into the rounded, 

lateral margin. Base line straight or slightly arcuate, 

upturned distally. Umbones subcentral or somewhat 

anterior, varying widely in height and degree of prominence; the apices acute and feebly prosogyrate. Lunule minute, cordate. Escutcheon minute, lanceolate. 

Surface sculptured with rather low, gently arched 

radiating costae, averaging about 15 and separated by 

narrower and mostly linear interspaces. Radials overridden by crowded, concentric lirations, most conspicuous anteriorly, obsolete in the interradial channels. 

Ligament external, opisthodetic. Dentition of right 

valve reduced apparently to a single cardinal, the 

anterior cardinal being fused, except in the very young, 

with the anterior margin of the valve and the posterior 

fused with the ligamentary nymph; middle cardinal 

strong and prominent, triangular,, the apex of the triangle directly beneath the apices of the umbones; 

anterior lateral socket short, double; posterior lateral 

tooth very low and inconspicuous; two cardinals in the 

left valve, of which the anterior is shorter and stouter, 

divergent on each side of the large subumbonal socket. 

Anterior left lateral short, posterior lateral socket shallow. Adductor impressions usually obscure. Pallial 

line simple. Inner margins denticulated in harmony 

with the external ribbing.

Say's species includes 2 distinct races in the fossil 

faunas, and these same distinctions, though somewhat 

less obvious, persist in the Kecent represenatives: the 

one a moderately heavy and convex shell with not very 

conspicuous umbones ancl about 15 rather low costae 

overridden by concentric lirae, which are not strong 

enough to nodulate the ribs; the other, a very heavy 

and convex little bivalve with very high and very 

prominent umbones and 10 to 13 or 14 vigorous radials 

overriden by nodulose concentric lirae. The smaller, 

less ornate form prevails north of the Hattaras atis 

during the Tertiary and off the Carolina coast in the 

Recent waters. The larger, more heavily sculptured 

race is especially characteristic of the Duplin and Waccamaw formations, and its somewhat reduced descendants stiir exist along the Florida coast and among the 

Keys.

The young, particularly in the Yorktown, are much 

less angular than the adults and quite frequently 

present a regularly transverse oval outline. The concentric lirae are usually strongest in the young, though 

in some of the northern individuals—both young and 

adult—they are almost obsolete.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; ^4 mile northeast of Smithfield, Benns 

Church, % mile from the old church and at Mr. Everet's 

farm near Benns Church, Isle of Wight County; % mile north 

of Chuckatuck, 1% miles southeast of Reids Ferry, 5% miles 

northwest of Suffolk, 1 mile west of Suffolk, 1% miles northeast 

of Suffolk, 1 mile northeast of Suffolk, % mile below the Suf-
PART 1. PELECTPODA 71

folk waterworks dam and along the drainage ditch east of 

Jericho ditch, Nansemond County.

North Carolina: Miocene, Yorktown formation, Palmyra 

Bluff, Halifax County; 4 miles northwest of Williamston, Martin County; 6% miles below New Bridge, 1 mile below Bells 

Bridge on the Tar River, Edgecombe County; 2 miles southeast 

of Tugwell, 1% miles northeast of Farmville, 3 miles south of 

Farmville, 2% miles north of Standard, 3 miles west of Greenville, 8 to 9 miles south of Greenville, 9 to 10 miles south of 

Greenville, 3 miles north of Grifton, and 2 miles east of Grifton, 

Pitt County; 2^ miles northwest of Chocowinity, Beaufort 

County; 1 mile west of Wilson (in Hominy Swamp, on the 

farm of Frank Barnes), Wilson County; 1 mile north of Castoria, and 1 mile east of Lizzie (on the farm of T. N. Lassiter), 

Greene County; Tar Ferry on Wiccacon Creek (opposite Harrellsville) and l1/^ miles below Tar Ferry, Hertford County; 

Colerain Landing and y2 to % mile above Edenhouse Point, 

Bertie County; Rock Landing on the Neuse River, Craven 

County. Duplin Marl, Natural Well, 1% miles north of Magnolia, and W. H. Kornegay's marl pit near Magnolia, Duplin 

County. Pliocene, Waccamaw formation, Lake Waccamaw, 

Cronly (half a mile east of the factories), and Neills Eddy 

Landing (3 miles north of Cronly), Columbus County.

Outside distribution: Miocene, Duplin marl, Porters Landing 

on the Savannah River, Efflngham County, Ga. Pliocene, Waccamaw formation, Nixons and Tillys Lake, Horry County, S. 

C. Caloosahatchee marl, De Leon Springs, Volusia County, 

Fla.; Kissimmee well (at a depth of 150 feet), Osceola County, 

Fla.; Caloosahatchee River, Fla. Croatan sand, Slocums Creek 

and Mallisons, Craven County, N. C. Pleistocene, Dismal 

Swamp canal, posts 15 to 16, Virginia; Simmons Bluff and 

Wadmalaw, S. C.; Kissimmee well (at a depth of 96 feet), 

Osceola County, Fla.; Eau Gallie, Brevard County, Fla.; Labelle, Hendry County, Fla. Recent off Hatteras in both shallow 

and deep water; off the Florida coast in shallow water only.

Glans (Pleuromeris) tridentata decemcostata (Conrad) Gardner

Plate 13, figures 1-4

1845. Cardita tridentata Say (part). Conrad, Fossils of the 

medial Tertiary of the United States, p. 76, pi. 43, 

fig. 11.

1856. Cardita tridentata Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 67, pi. 19, figs. 9, 10.

1858. Cardita abbreviata Emmons, North Carolina Geol. Survey 

Rept, p. 302, fig. 236. Not C. abbreviata Conrad, 1841.

1867. Pleuromeris decemcostata Conrad, Am. Jour. Conchology, 

vol. 3, p. 12.

1903. Venericardia (Pleuromeris) tridentata Say (part). Dall, 

Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1433.

1932. Venericardia (Pleuromeris) tridentata decemcostata Conrad. Mansfield, Florida Geol. Survey. Bull. 8, p. 89, 

pi. 16, figs. 3, 4.

Triangular; ribs 12, rounded, ornamented by numerous angular or transverse tubercles over all the ribs.—Conrad, 1867.

Shell very heavy, convex, trigonal, subequilateral. 

Anterior end rather evenly rounded. Posterior end 

obliquely truncate dorsally, rounded laterally. Base 

line straight. Umbones high, heavy, prominent, and 

erect except at the apices, which are slightly prosogyrate. Lunule minute, stoutly cordate. Escutcheon 

minute, lanceolate. Surface strongly corrugated, with 

about 13 elevated costae radiating fanlike from the

umbones; interradial channels deep and narrower than 

the radials. Radials overridden and more or less nodulated, particularly on the anterior half of the shell, by 

the vigorous, concentric lirae which, however, do not 

penetrate the interradial channels. Dentition normal 

in number for the species, but much more robust, especially the subumbonal cardinal of the right valve. 

Muscle impressions submedial or a little below the 

median horizontal and rather small—the anterior reniform, the posterior roughly rotund or elliptical. Pallial line simple, rather distant. Inner margins strongly 

fluted by the external costae.

This stout, ornately sculptured form of Pleuromeris 

tridentata Say apparently reaches its maximum size 

and vigor of sculpture during the Waccamaw. The 

same features, however, that have led to its subspecific 

isolation from the type prevalent north of the Hatteras 

axis still persist, though to a lesser degree, and characterize the representatives of the species that inhabit the 

Florida shores and Keys.

In Florida in the Choctawhatchee, Glans (Pleuromeris) tridentata dec&mcostata is common in both 

EcpJwra and Cancellaria zones.

Distribution: North Carolina: Miocene, Yorktown formation, 

3 miles southwest of Frog Level, Pitt County. Duplin marl, 

2% miles south of Clinton, Sampson County; Natural Well, 

1% miles north of Magnolia and the marl pits of Frank 

Wilson and W. H. Kbrnegay, Duplin County; 4 miles north of 

Lumberton (on the Berry Godwin plantation), 1 mile west of 

Lumberton (on the property of Charles Rowland), Lumberton 

(near the bottling works), 2 miles below Lumberton, 4 to 5 

miles below Lumberton, 1^ miles northeast of Fairmont, and 

at Fairmont (Ashpole), Robeson County; 4 miles south of 

Clarkton, Bladen County. Pliocene, Waccamaw formation, 50 

miles above Wilmington and at Walkers Bluff, on the Cape 

Fear River, Bladen Cdunty; Lake Waccamaw and Neills Eddy 

Landing (3 miles riorth of Cronly on the Cape Fear River), 

Columbus County; Wilmington (on Smiths Creek and at the 

city rock quarry), New Hanover County.

Outside distribution: Miocene, Duplin marl, Sumter district, 

Sumter County, S. C. Choctawhatchee formation, northern 

Florida. Pliocene, Waccamaw formation, Nixons and Tillys 

Lake, Horry County, S. C. Caloosahatchee marl, Caloosahatchee River, Fla. Recent off the coast of Florida in shallow 

water.

Subgemis? PTEROMERIS Conrad, 1862

1862. Pteromeris Conrad, Acad. Nat. S«i. Philadelphia Proc. 

for 1862, vol. 14, p. 290.

Type by original designation: Cardita perplana Conrad.

Triangular, not oblique, with radiating ribs; beaks medial: 

hinge of left valve, anterior tooth direct or directed slightly 

toward the anterior margin; posterior tooth double or bifid.— 

Conrad, 1862.

Only faint traces of a lateral dentition can be observed in this small group. It does not seem sufficiently 

important to be given generic rank, but it differs so 

markedly in form and dentition from Glans, probably 

its closest ally, that I hesitate to unite them generically.
72 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Glans (Pteromeris) perplana (Conrad) Gardner

Plate 13, figures 6-9

1841. Cardita perplana Conrad, Am. Jour. Sci., 1st ser. vol. 41, 

p. 347, pi. 2, fig. 16.

1845. Astarte radians Conrad, Fossils of the medial Tertiary 

of the United States, p. 77, pi. 43, fig. 13.

1846. Astarte fiabella Conrad, Acad. Nat. Sci. Philadelphia Proc.,

vol. 3, p. 24, pi. 1, fig. 3. 

1856. Cardita perplana Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 68, pi. 19, fig. 11. 

1858. Cardita perplana Conrad. Emmons, North Carolina Geol.

Survey Kept., p. 302, fig. 235. 

1863. Actinobolus (Pteromeris) radians Conrad, Acad. Nat.

Sci. Philadelphia Proc. for 1862, p. 578. 

1885. Venericardia oblique, Bush, Connecticut Acad. Trans., vol.

6, p. 478. 

1903. Venericardia (Pteromeris) perplana Conrad. Ball, Acad.

Nat. Sci. Philadelphia Proc. for 1902, p. 705. 

1903. Venericardia (Pteromeris) perplana Conrad. Ball, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1434.

Trigonal, nearly flat; ribs about 11, angular, minutely 

granulated.—Conrad, 1841.

Type locality: Natural Well, Duplin County, N. C.

Shell small, trigonal-ovate, compressed to apparent 

flatness. Lunule and escutcheon sublinear-lanceolate, 

the latter only a little longer and narrower than the 

former. Umbones high, compressed, with acute and 

feebly prosogyrate apices, placed about one-third the 

length in front of the posterior margin; apical angle 

running between 70° and 85°. Anterior end obliquely 

produced. Dorsal margins slightly concave in lunular 

region. Lateral margin evenly rounded. Posterior 

dorsal slope much more steep than anterior, merging 

rather abruptly into the base. Ventral margin horizontal medially, strongly upcurved distally. Surface 

corrugated with 10 to 15 or 16 rather low, broadly 

arched, radial costae, separated mostly by linear interradials; radials overridden by microscopic undulatory 

growth lines. Ligament external, opisthodetic; nymph 

relatively broad, bounded dorsally by a deep groove. 

Hinge dentition vigorous; in the right valve, a feeble 

laminar anterior cardinal and a very stout, triangular, 

medially sulcate, middle cardinal; posterior right cardinal fused with ligament nymph; in the left valve, two 

bifid cardinals—the anterior shorter and more compressed—separated by the deep subumbonal socket; 

anterior lateral margin of right valve and posterior 

margin of left feebly grooved to receive the more or 

less beveled edges of the opposite valve. Adductor 

muscle impressions usually distinct, the posterior semielliptical and slightly higher than the reniform anterior scar. Pallial line entire, distant. Inner margin 

crenulated in harmony with the external ribbing.

Pteromeris perplana Conrad is notably unstable during the Late Tertiary. The species varies in convexity 

and outline from relatively high and less compressed 

forms, which are isolated under the subspecies abbre- 

, to broader individuals in which the cavity is

scarcely thicker than the outer shell covering. In the 

Kecent species, the radials rarely number fewer than 

12 or more than 14, whereas in the Miocene they may 

number as few as 10 and, if the subspecies abbreviata 

be included, up to 18 or 20. In the Waccamaw, the 

species attains its maximum size and compression. The 

dimensions of a valve from Walkers Bluff are as follows: Height 10.3 millimeters, width 9.6 millimeters, 

convexity 1.6 millimeters, thickness of shell itself 1.0 

millimeter. Individuals pursuing this line of development are further characterized, as a rule, by a more 

distant and angular radial sculpture and by a broader, 

less elevated hinge dentition.

Bistribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 5% miles northwest of Suffolk, 1 mile west 

of Suffolk, 1 mile northeast of Suffolk, and at Suffolk (^ mile 

below the waterworks dam), Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% miles 

northeast of Farmville, 8 to 9 miles southeast of Greenville, 

and 9 to 10 miles south of Greenville, Pitt County; 3 to 4 

miles below Tar Ferry, Hertford County; Colerain Landing on 

the Chowan River, Bertie County; Rock Landing on the Neuse 

River, Craven County. Buplin marl, 10 miles south of Clinton, 

Sampson County; Natural Well, 1% miles north of Magnolia, 

and W. H. Kornegay's marL pit near Magnolia, Buplin County; 

Lumberton and 2 miles below Lumberton,»Robeson County. 

Pliocene, Waccamaw formation, Walkers Bluff on the Cape 

Fear River, Bladen County; Lake Waccamaw, Cronly, and 

Neills Eddy Landing on the Cape Fear (3 miles north of 

Cronly), Columbus County; city rock quarry near Wilmington, 

New Hanover County.

Outside distribution: Miocene, Buplin marl, Porters Landing, 

Effingham County, Ga. Pliocene, Waccamaw formation, Nixons 

and Tillys Lake, Horry County, S. C. Caloosahatchee marl, 

Caloosahatchee River and Shell Creek, Fla. Croatan sand, 

Slocums Creek, Craven County, N. C. Pleistocene, Kissimmee 

well (at a depth of 96 feet), Osceola County. Recent, Hatteras 

to Charlotte Harbor in 14 to 52 fathoms.

Glans (Pteromeris) perplana abbreviata (Conrad) Gardner

Plate 13, figures 19-22

1841. Cardita abbreviata Conrad, Am. Jour. Sci., 1st ser., vol.

41, p. 347, pi. 2, fig. 17. 

1845. Astarte abbreviata Conrad, Fossils of the medial Tertiary

of the United States, p. 77, pi. 43, fig. 12. 

1856. Cardita abbreviata Conrad. Tuomey and Holmes, Pleio- 

. cene fossils of South Carolina, p. 69, pi. 19, fig. 12. 

1863. Actinobolus (Pteromeris) abbreviata Conrad, Acad. Nat.

Sci. Philadelphia Proc. for 1862, p. 578.

1903. Venericardia (Pteromeris) perplana var. abbreviata Conrad. Ball, Wagner Free Inst. Sci. Trans., vol. 3, pt.

6, p. 1435. 

1932. Venericardia (Pleuromeris) perplana var. abbreviata

(Conrad). Mansfield, Florida Geol. Survey Bull. 8, p.

88, pi. 16, fig. 5.

Trigonal, elevated, convex-depressed, ribs about 11, convex, 

minutely granulated; posterior extremity angulated. This and 

the preceding species [Cardita perplana} belong to the genus 

Venericardia of Lam.—Conrad, 1841.

Type locality: Wilmington, N. C. 

Venericardia perplana abbreviata Conrad is a little 

less compressed than perplana s. s., is higher, and never
PART 1. PELECYPODA 73

attains the size of the latter. The radials vary in number from 10 to 20, and their prominence is inversely 

proportional to their. number. Concomitant with the 

variation in outline is also a variation in the character 

of the hinge—particularly toward a narrow ligamentary nymph—and a greater inequality of the two 

left cardinals.

Both the subspecies and the species originated apparently in the Yorktown formation. North of the 

Hatter as axis abbreviata is distinctly the prevailing 

type; south of it perplana s. s. is equally prominent in 

the Duplin and Waccamaw and, after the close of the 

Pliocene, quite excludes th'e relatively higher and more 

inflated form. In Florida abbreviata is common in the 

Ecphora zone of the Choctawhatchee formation and 

rare in the Cancellaria zone above it. ,

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Benns Church, ^4 mile from the old church 

and Everet's farm near Benns Church, Isle of Wight County; 

14 mile north of Chuckatuck, 1% miles southeast of Reids 

Ferry, 5% miles northwest of Suffolk, 1 mile west of Suffolk, 

1 mile northeast of Suffolk, Suffolk, and 1% miles below the 

Suffolk waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, 3 to 4 miles 

below Tar Ferry, Hertford County; 3 miles south of Farmville, 

8 to 9 miles south of Greenville, 9 to 10 miles south of Greenville, 2 miles east of Grifton (on J. F. Brooks' farm), Pitt 

County; 2 miles southwest of Maple Cypress, Bock Landing, 

Craven County; 1 mile west of Wilson (on Frank Barnes property in Hominy Swamp), Wilson County; 1 mile north of 

Castoria, Greene County. Duplin marl, Natural Well, 1% 

miles north of Magnolia, and W. H. Kornegay's marl pit near 

Magnolia, Duplin County; 1 mile west of Lumberton (on the 

property of Charles Rowland), Lumberton (near the bottling 

works), 2 miles below Lumberton, and 1% miles northeast of 

Fairmont (on the property of Andrew Jones), Robeson County. 

Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear 

River, Bladen County; Lake Waccamaw and Neills Eddy Landing, on the Cape Fear River (3 miles north of Cronly), 

Columbus County; and city rock quarry near Wilmington, New 

Hanover County.

Outside distribution: Miocene, Hawthorn formation, Porters 

Landing, Effingham County, Ga. Duplin marl, Darlington, Darlington County, S. C. Choctawhatchee formation, northern 

Florida. Pliocene, Waccamaw formation, Nixons and Tillys 

Lake, Horry County, S. C. Caloosahatchee marl, Shell Creek, 

Fla. Croatan sand, Slocums Creek, Craven County, N. C.

Family CONDYLOCARDIIDAE Bernard

This family was instituted by Bernard for some extremely 

minute bivalves, related to the Carditidae but which retain 

in the adult state the immaturity of hinge characters which 

characterizes the nepionic shells of Ca!r<Lita and, moreover, 

have the resilium sunken and centrally located between the 

valves. The prodissoconch in this group is of the usual size 

but appears very prominent on account of the relatively small 

additions made to it in growth.—Dall,39 1903.

88 Dall, W. H., Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1436, 

1903.

Genus ERYCINELLA Conrad

1845. Erycinella, Conrad, Fossils of the medial Tertiary of the 

United States, p. 74.

Type by monotypy: Erycinella, ovalis Conrad.

This genus is nearly allied to Erycina of Lamarck but has 

four teeth in the left valve. In the opposite valve the two teeth 

diverge, are rather long, and curving slightly inward, and 

the posterior one inclining to be double.—Conrad, 1S45.

Shell small, oval, radially sculptured, with an external ligament and internal resilium situated between the cardinals, of 

which there are 2 in each valve; in the left valve the edges 

of the resiliary chondrophore are somewhat raised, so that 

when worn the valve appears to contain four cardinals, but I 

think these ridges are not of the nature of true teeth; in the 

right valve the posterior cardinal is stout and triangular 

and feebly grooved; there is a feeble, elongate, posterior right 

and anterior left lateral, which fits into a groove in the margin 

of the opposite valve; the inner margins of the valves are 

crenulated.—Dall,40 1903.

This genus includes a few Tertiary and Recent 

species from the cooler waters.

In addition to the 2 well-developed cardinals in the 

right valve, there is a third—a laminar, somewhat rudimentary anterior cardinal. It is the middle and not 

the posterior cardinal that is stout and trigor.al.

Erycinella ovalis Conrad

Plate 14, figure 46

1845. Erycinella, ovalis Conrad, Fossils of the medial Tertiary 

of the United States, p. 74, pi. 42, fig. 5.'

1857. Erycina ovalis (Conrad). D'Orbigny, Prodrome pale"ontologie, vol. 3, p. 115.

1863. Erycinella ovalis Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, p. 578.

1864. Erycmella ovalis Conrad. Acad. Nat. Sci. Philadelphia

Proc. for 1864, p. 212. 

1903. Erycinella ovalis Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1438, pi. 53, fig. 2.

Not Erycinella ovalis S. V. Wood, 1853.

Very small, obliquely ovtel from beak to base, convex, with 

indistinct radiating lines; posterior side shorter than the 

anterior; basal margin obliquely rounded; cardinal tet'th robust; 

inner margin crenulated. Locality, Yorktown, Va.—Conrad, 

1845.

Shell minute, moderately convex, but heavy and rude, 

oval, slightly oblique, and inequilateral. Anterior 

margin descending at a very steep angle from the umbones almost to the base^, with which it unites in a 

broad, even curve. Posterior dorsal margin a trifle 

convex and produced. Lateral margin squarely or 

somewhat obliquely truncated but rounding gently into 

the base. Umbones moderately inflated even to their 

apices, which are proximate, involute, and very feebly 

prosogyrate. Sculpture of some 20 to 30 very low,

40 Dall, W. H., Wagner Free Inst./Sci. Trans., vol, 3, pt. 6, p. 1436, 

1903.
74 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

relatively broad radials that are least feeble near the 

ventral margin and are, as a rule, quite obsolete in the 

umbonal region; 3 or 4 resting stages usually discernible under magnification. Ligament both external and 

internal; external ligament mounted on minute linear 

nymphs, which run parallel to the posterior dorsal 

margin; internal ligament lodged in a subumbonal resilial pit between the cardinals. Hinge of right valve 

armed with 3 cardinals—the anterior cardinal rudimentary and laminar; the middle rude but robust, 

roughly trigonal, simple, or feebly sulcate; the posterior 

simple, oblique, and compressed. Left cardinals 2 in 

number—the anterior cardinal oblique, compressed, 

sometimes longitudinally sulcate; the posterior somewhat shorter and more compressed than the anterior; 

distal edges of resilial pit raised, thus simulating cardinals, particularly in the more weathered individuals. 

JMuscle impressions small, slightly below the median 

horizontal—the anterior somewhat reniform, the posterior oval-elongate. Inner margins feebly crenulated. 

ErycineTla, ovalik Conrad is the only representative 

of this minute but well-characterized genus in the east 

coast Miocene. Though not confined exclusively to 

the Yorktown formation of Virginia, it is abundant only 

along the York River and in the environs of Suffolk.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Benns Church, 1,4 mile from the old church 

and Mr. Everet's farm near Benns Church, Isle of Wight 

County; 14 mile north of Chuckatuck, 1% miles southeast of 

Reids Ferry, 1 mile west of Suffolk, 1 mile northeast of Suffolk, half a mile below the Suffolk waterworks dam, and along 

the drainage ditch just east of the Jericho ditch, Nansemond 

County.

North Carolina: Miocene, Yorktown formation, Greenville 

(just east of the county bridge) and 9 to 10 miles south of 

Greenville, Pitt County (very rare) ; Tar Ferry on Wiccacon 

Creek (opposite Harrellsville), Hertford County; Colerain 

Landing, Bertie County.

Pelecypoda (incertae sedis) 

Plate 14, figures 33-36

Shell minute but solid. Valves evenly inflated, obliquely ovate in outline. Umbones low and very obtuse, 

placed within the posterior third of the shell. Lunule 

and escutcheon not differentiated. Posterior end quite 

evenly rounded from the umbones to the ventral margin. Anterior end obliquely produced, but rounding 

evenly into the base. Ventral margin less strongly 

upcurved before than behind. Outer surface with a 

dull luster, devoid of sculpture. Hinge moderately 

heavy for the size of the shell. Ligament external, 

lodged in a short, shallow, marginal groove behind the 

umbones. Resilium internal, lodged in a small resilial 

pit behind the cardinals, separated from the ligament 

by a shelly buttress. Cardinals three in number in 

each valve; anterior cardinal of right valve elongated, 

laminar; middle cardinal heavy, trigonal, feebly sulcated on its ventral margin; posterior cardinal either 

rudimentary or broken, probably the former, as the 

two valves were found united; anterior cardinal of 

left valve also laminar and elongated but less than that 

of the right; medial cardinal moderately heavy, simple; 

posterior cardinal placed near the medial, very short 

and quite slender. Muscle scars obscure, the anterior 

pyriform and placed a little below the median horizontal, the posterior elliptical, subniedial in position. 

Pallial line indistinct, entire. Inner margins simple.

Dimensions of figured specimen: Height 1.7 millimeters, width 1.8 millimeter; diameter 1.0 ± millimeter-.

Figured specimen: U. S. Nat. Mus. 325557.

Even the more distant affinities of this minute bivalve are exceedingly doubtful. The diagnostic characters are the posterior position of the obtuse umbones; 

the smooth external surface; the internal resilium 

placed behind the cardinals and not between them; the 

peculiar, short, slender, posterior cardinal of the left 

valve; and the absence of any pallial sinus.

The form is persistently suggestive of ErycineTla 

Conrad in spite of quite radical differences, and for 

that reason it has been placed tentatively with the 

latter near the Condylocardiidae of Bernard. It differs 

from other members of the family by the establishment 

of the resilium behind the cardinals instead of between 

them; by the presence of 3 left cardinals instead of 2; 

and by the absence of any suggestion of radial sculpture 

either externally or on the inner ventral margins. The 

absence of a lunule or escutcheon, the blunt posterior 

umbones, and the entire pallial line suggests, however, 

a comparatively primitive form. The absence of laterals and the discrepant cardinals exclude it from the 

Cyrenacea. It has therefore been placed among the 

primitive Carditacea, although its position is by no 

means assured.

Distribution: Virginia: Miocene, Yorktown formation, Suffolk, 

Nansemond County.

Superfamily LUCINACEA 

Family LUCINIDAE

A comprehensive and valuable study of the relationships of the lucinoids has been made by Chavan,41 who 

illustrates the genera and offers a chronological table 

of the evolution of the Lucinas.

Genus CTENA Morch

1861. Ctena Morch, Malakozoologische Blatter, vol. 7, p. 201. 

1869. Jagonia Recluz, Soc. linneenne Bordeaux Actes, vol. 27 

(ser. 3, vol. 7), p. 37.

Type by subsequent designation (Dall, Bartsch, and Rehder,. 

B. P. Bishop Museum Bull. 153, p. 128, 1938) : Oodakia pectinata 

Carpenter (not Gmelin)=Cf. mesdcana Dall. Lower California 

to Panama and Ecuador.

°- Chavan, A., Bssai critique de classification des Lucines: Jour, conchyliologie, vol. 81, pp.. 133-153, 198-216, 237-282, 1937; vol. 82, pp. 

59-97, 105-130, 215-241, 1938.
PART 1. PELECYPODA 75

Shell of medium size, suborbicular to transversely oval, 

moderately compressed. Beaks small, pointed, median 

or slightly posterior. Lunule narrow, lanceolate, depressed. Ligament covered with a calcareous coating 

and typically inset with the resilium. Two cardinals 

and anterior and posterior laterals in each valve. Anterior muscle scar elongated, the posterior rudely quadrate. Pallial line simple. Outer surface radially 

corded and concentrically threaded. Inner margin 

smooth or feebly crenate.

The group, formerly referred to Codakia (Jagonia}, 

is separated from Codakia Scopoli by its more prominent, more posterior umbones, larger lunule, relatively 

stronger radial sculpture, and its heavier posterior 

laterals.

Both the Tertiary and the Recent species of Ctena 

are restricted in number of both species and individuals 

but have a fairly wide distribution in the tropical and 

temperate faunas.

Ctena speciosa (Rogers and Rogers) Gardner

Plate 13, figure 33

1837. Lucina speciosa Rogers and Rogers, Am. Philos. Soc. Trans.,

new ser., vol. 5, p. 333, pi. 26, fig. 6. 

1840. Lucina squamosa Conrad, Fossils of the medial Tertiary

of the United States, p. 38, pi. 20, fig. 1. Not L. squamosa

Lamarck, 1818. 

1856. Lucina squamosa Lamarck. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 57, pi. 18, figs. 6, 7. 

1858. Lucina squamosa Lamarck. Emmons, North Carolina Geol.

Survey Rept, p. 291 (name only).

1863. Codakia speciosa Rogers. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 577. 

1803. Codakia (Jagonia) speciosa "Rogers. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1350.

Shell subelliptical, inequilateral, inflated, rather thin, with 

equal, close-set, rather elevated, longitudinal ribs and regular, 

very close, concentric striae; lunule small, very distinct, and 

ovate-lanceolate; beaks small, pointed, and slightly prominent 

beyond the general curve of the margin, placed about one-third 

the transverse length of the shell from the anterior end; cardinal 

teeth small, diverging; lateral teeth equal, distinct, and nearly 

equidistant from the anterior cardinal; hinge margin regularly 

arcuated; the rest of the margin, especially the posterior side, 

crenate within; posterior muscular impression elongated and 

slightly curved. Diameter three-tenths, length eleven-twentieths, height nine-twentieths of an inch.

This very beautiful shell occurs in nearly all the localities of 

the Miocene in the James River region.—W. B. and H. D. Rogers, 

1837.

A right valve (U. S. Nat. Mus. 145067) from the 

Yorktown formation at Bellefield, Va., is figured. It 

measures 14.1 millimeters in height and 16.4 millimeters 

in width.

The Rogerses' species is larger than Ctena magnoUana (Dall), is decidedly convex, and the sculpture, 

though of the same general type, is much coarser.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown on the York River, York County: "James River region" 

(W. B. and H. D. Rogers).

North Carolina: Miocene, Duplin marl, Natural Well and 1% 

miles north of Magnolia, Duplin County.

Outside distribution: Miocene, Duplin marl, Darlington, Darlington County, S. C. Pliocene, Caloosahatchee marl, Caloosahatchee River and Shell Creek, Fla. Pleistocene, Labelle, Hendry 

County, Fla. (Vaughan).

Ctena magnoliana (Dall) Gardner

1903. Codakia (Jagonia) magnoliana, Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1349, pi. 52, fig. 17. 

1932. Codakia (Jagonia) magnoliana Dall. Mansfield, Florida

Geol. Survey Bull. 8, p. 93, pi. 20, fig. 1.

Shell small, thin, inequilateral, the beaks five-elevenths of the 

whole length in front of the posterior end; both ends rounded, 

base arcuate, lunule narrow, lanceolate, no distinct dorsal areas; 

sculpture of numerous, even, fine, close-set, rarely divaricate, 

similar, radial riblets, crossed by fine, rounded, equal, close-set 

threads, narrower than the riblets, and which in crossing the 

latter are slightly arcuate convexly towards the beaks, making 

a very elegant though minute type of sculpture; hinge thin and 

delicate, but the teeth, especially the right laterals, very distinct; > scars normal; margins delicately crenulate. Height 9.5, length 

11.5, diameter 4.5 millimeters.

This species is of the fully differentiated Jagonia type, and its 

sculpture is notably elegant.—Dall, 1903.

Holotype, a right valve: U. S. Nat. Mus. 115113.

Type locality: Magnolia, Duplin County, N. C. 

Duplin marl.

The distribution of Ctena magnoliana in Florida is 

restricted to the Cancellaria zone of the Choctawhatchee 

formation.

Distribution: North Carolina: Miocene, Duplin marl. Natural 

well and 1% miles north of Magnolia, Duplin County. Rare.

Ctena microimbricata Gardner n. sp.

Plate 13, figures 31, 32

Shell small, thin, moderately inflated, transversely 

ovate, inequilateral. Umbones rather tumid, only a little more than one-third the total length in front of the 

posterior margin, their apices flattened and proximate. 

Lunule elongate-lanceolate, smooth,- depressed, but 

not bounded by an incised line. Escutcheon absent. 

Anterior end more produced than the posterior; semielliptical. Posterior dorsal margin more oblique than 

the anterior dorsal, merging gradually into the rounded 

lateral margin. Base line arcuate. Entire external 

surface covered with closely appressed concentric imbrications, overlapping dorsally, and evenly and minutely crenulated by the fine, crowded radials. Ligament inset, opisthodetic, mounted on a narrow, obliquely 

elongated nymph. Anterior cardinal of right valve 

short and thin; right posterior cardinal subumbonal, 

moderately compressed, feebly sulcated. Anterior and 

posterior laterals sharp, distant, triangular, and prominent though slender. Muscle impressions obscure. Pallial line entire. Marginal crenulations delicate.

Dimensions of holotype: Height 9.8 millimeters, 

width 11.2 millimeters, convexity 2.8 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325540.
76 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl.

Otena rmcroimbricata^ n. sp., constitutes the end member of a very interesting series, which includes C. speciosa (Rogers and Kogers) and C. magnoliana (Dall), 

and in which the sculpture, though of the same general 

type throughout, becomes increasingly fine and more 

delicate. The Duplin forms never-equal the Rogerses' 

species in size or degree of convexity. The radials in 

all three of the species are approximately uniform in 

strength over the entire external surface and are frequently bifurcating. In valves of the same size, the 

radials of C. speciosa number 2% to the millimeter, 

those of C. magnoliana 3, and those of 0. microimbricata 

4. The concentric elevations run about 6 to the millimeter in C. speciosa, 9 in C. magnoliana, and 13 in C. 

Tmcroimbricata. A corresponding increase in regularity and in closeness of the appression to the surface is 

evident. In the new species the detail of the sculpture 

is microscopically fine. Concomitant with the thinner 

shell is the thinner and more delicate hinge and the 

finer marginal crenulation. The hiatus between C. speciosa and C. magnoliana is very much less obvious than 

that between C. magnoliana and C. microimbricata.

The species is described from a single right valve.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, Duplin County.

Genus PHACOIDES Blainville

1825. Phacoides Blainville, Manue.1 de malacologie et de conchyliologie, vol. 1, p. 550.

Type by monotypy: Lucina jamaicensiq Lamarck=Tellina pectinata Gmelin. Recent in the West Indies.

Shell more or less lenticular; compressed, as a rule, or 

only slightly tumid. Umbones low, subcentral, erect or 

prosogyrate. Lunule commonly profound. Escutcheon 

obsolete. Anterior and posterior dorsal* areas usually 

differentiated. Sculpture dominantly concentric. Ligament external, in many specimens deeply sunken; normal dentition of right valve consisting of a simple anterior cardinal, a bifid posterior cardinal, and heavy 

anterior and posterior laterals; normal dentition of 

left valve consisting of a bifid anterior cardinal, a simple posterior cardinal, and heavy anterior and posterior 

lateral sockets; laterals in many specimens, and cardinals in some, obsolete. Muscle impressions strongly 

marked, the posterior oval, the anterior narrow, elongated, parallel to the pallial line. Pallial line entire. 

Inner margins smooth or crenulated.

The genus is abundantly represented in the Tertiary, 

and related forms are present in the Mesozoic and 

possibly in faunas even more ancient. The living species 

number more than 100, and, though most prolific in 

the tropics, they are present in the temperate seas as 

well.

Subgenus CARDIOLTICINA Sacco

1901. Cardiolucina Sacco, I Molluschi dei Terreni Terziarii del 

Piemonte e della Liguria, pt. 29, p. 89.

Type by original designation: Cardium agassizii Michelotti. 

Middle and upper Miocene of northern Italy.

C' ardiolucina, as Woodring indicated in 1925, includes 

many of the common east coast Miocene and Pliocene 

lucinoids formerly referred to Cavilucina. They are 

characterized by small, commonly inflated valves, 

broadly rounded and produced anterior margins, a short, 

deep, lunular depression, inconspicuously differentiated 

dorsal areas, a strong concentric sculpture, with or 

without a feeble radial component, a well-developed cardinal and lateral dentition, and a finely crenate inner 

margin. , *

Chavan,42 1937, considered Cardiolucina a synonym of 

Bellucina Dall, 1901.

In order to place some of the species from the American Tertiary, he erected the genus Cavilinga and designated as the type Lucina trisulcata Conrad of the upper 

Miocene and Pliocene faunas of the southeastern United 

States. He included under Cavilinga not only the group 

of Upper Tertiary forms commonly referred to Cardiolucina but also a number *)f middle and upper Eocene 

species, such as L. pomilia Conrad and L. alveata Conrad. There are no examples of Sacco's subgenotype in 

the collections of the U. S. National Museum, and the 

acceptance of Chavan's subgenus is delayed in the hope 

of later consulting material upon which Sacco bas;ed 

his Cardiolucina.

Woodring observed that Cardiolucina is one of many 

Middle and Upper Tertiary groups persistent in the 

Recent West Indian faunas but not recorded from European seas.

Phacoides (Cardiolucina) trisulcatus multistriatus (Conrad)

Plate 13, figures 25, 26

1843. Lucina multistriata Conrad, Acad. Nat. Sci. Philadelphia 

Proc., vol. 1, p. 307.

1863. Codakia multistriata Conrad (part), Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 577.

1903. Phacoides (Cavilncina) trisulcatus var. multistriatus Conrad. Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, 

p. 1370.

1932. Phaooides (Cwrdiolkicina,) trisulcatus multistriatus (Conrad). Mansfield, Florida Geol. Survey Bull. 8, p. 96, 

pi. 20, figs. 15, 16.

Oval, equilateral, slightly ventricose, with fine, prominent, 

closely arranged, concentric, and minute radiating lines; disk 

with 2 or more distinct undulations on the inferior half; beaks 

prominent; dorsal margins profoundly declining; anteripr lateral 

tooth distinct, remote; inner margin minutely crenulated; lunule 

elliptical, slightly impressed. Height, one-third of an inch.

Locality, Wilmington, N. C.—Conrad, 1843.

42 Chavan, A., Essai critique de classification des Lucines (Suite), Jour, 

conchyliologie, vol. 81, p. 205, 1937.
1. PELECYPODA 77

The figured left valve (U. S. Nat. Mus. 325538), measures 5.8 millimeters in height and 6,3 millimeters in 

width. It is from the Waccamaw formation in the city 

rock quarry at Wilmington, N. C.

Shell small, rudely circular or ellipsoidal, moderately 

gibbose. Lunule very small but very deepty excavated. 

Escutcheon absent. Umbones usually a little behind the 

median line, acute, prosogyrate, thrown into prominence 

by the profound lunular pit in front of them. Anterior 

end produced, very broadly rounded or obscurely truncated laterally. Posterior end shorter. Posterior dorsal 

margin oblique or slightly convex; lateral margin 

broadly rounded or squarely truncate. Base line 

broadly arcuate. Posterior dorsal area defined by an 

obscure carina and by a change in direction and character of the concentric lamination. Surface sculptured 

with strong, closely spaced, concentric lirae, which are 

finer and more crowded on the adolescent shell; a feeble 

radial striation, which is absent in the trisulcatus s. s., 

is rather evident in the subspecies. Ligament marginal. 

Normally, a simple anterior cardinal and a bifid posterior cardinal in the right valve; a bifid anterior and a 

simple posterior cardinal in the left valve; anterior 

cardinals becoming obsolete with age, and even the 

posterior cardinals sometimes affected; laterals rude 

but prominent; short anterior and posterior lateral denticles in the right valve; anterior and posterior lateral 

grooves in the left valve—the inner margins raised into 

toothlike prominences. Adductor impressions often 

obscure; the anterior linguiform, the posterior oval. 

Pallial line simple. Marginal denticulation very fine.

Phacoides (Cardiolucina) crenulatus (Conrad), the 

only species with which P. trisulcatus is confusable, is 

a much thinner and usually smaller shell with a more 

evenly rounded outline, and with more uniformly central and less prominent umbones, a much less deeply 

excavated lunule, a finer concentric sculpture, and a less 

rude and vigorous dentition. The aspect of the interior 

of the valve of P. trisulcatus is very characteristic— 

the posterior dorsal margin ascending with a slight convexity to the acute apices, the small but almost semicircular lunule pit in front of the umbones, and the 

anterior dorsal margin sloping gently to the lateral 

truncation.

The subspecies differs from the normal type only in 

having a feeble radial sculpture. Unlike P. trisulcatus 

s. s., it is apparently restricted in the Carolinas to 

the Duplin and Waccamaw formations. In the Choctawhatchee of Florida it has been reported only from the 

CanceUari/- zone. The P. (Cardiolucina,) trisulcatus 

group is reported by Olsson from both Tertiary and 

Recent faunas of mid-4-merica.

Distribution: North Carolina: Miocene, Duplin marl, 4 miles 

north of Lumberton and 1% miles northeast of Fairmont, Robeson 

County. Pliocene, Waccamaw formation, Walkers Bluff on the 

Gape Fear River, Bladen County; city rock quarry near Wilmington, New Hanover County.

401033—43———6

Outside distribution: Miocene, ChoctawhatChee formation, 

northern Florida.

Phacoides (Cardiolucina) postalveatus Gardner, n. sp.

Plate 13, figure 17

Shell small, heavy, subglobose., Umbones central with 

prosogyrate apices, high enough to break the even curve 

of the valvular margins. Lunule subrotund; depressed 

but not excavated. Surface concentrically sculptured 

with broad, heavy, tabulated elevations, which are more 

or less fused in the adult. Ligament opisthodetic, elongated, sunken. Dentition rude but vigorous. Left anterior cardinal feebly bifid; posterior simple; anterior 

and posterior lateral pits small but deep. Dentition of 

right valve unknown. Inner margins finely crenulate.

Dimensions of holotype: Height 3.3 millimeters, width 

3.4 millimeters, convexity 1.4 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325539. .

Type locality: Yorktown, York County, Va. Yorktown formation.

This sturdy little species is set apart from the coexistent Cardiolucinas by the broadly tabulated concentric elevations. It is, however, differentiated with 

greater difficulty from certain mutants of the Eocene 

P. (Cardiolucina) alveatus Conrad, prolific in the sands 

of the Claiborne group. Only 2 valves—both left 

valves—of the Yorktown species have been recovered. 

The larger of these is apparently adult. It is smaller 

than the average alveatus and is more regular in outline because of the less prominent umbones. The fusion 

of the concentric sculpture is seemingly more complete 

in the later form, for in alveatus some trace of the component costae is usually retained in more or less feeble 

striations that are continuous across the disk.- These 

do not occur in postalveatus except on the extreme distal 

margins. On the contrary, the 3 broad elevations 

formed by the fusion of the costae on the lower twothirds of the valve are smooth and polished and are 

slightly undercut by the channels behind them.

P. (Cardiolucina) postalveatus may possibly be the 

much reduced descendant of the flourishing alveatus of 

the Early Tertiary.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown on the York River, York County.

Submenus LUOINISCA Ball

1901. Lucinisca Dall, U. S. Nat. Mus. Proc., vol. 23, p. 805. 

1937. Lucinisca Chavan, Jour, conchyliologie, vol. 81, p. 238.

Type by original designation: Lucina nassula Conrad. Hatteras to Cuba and west to Mobile Bay in 7 to 200 fathoms.

Shell lentiform, white, with well-marked dorsal areas, the 

sculpture reticulate and muricate, the right anterior cardinal 

obsolete.—Dall, 1901.

Phacoides (Lucinisca) cribrarius (Say) Dall 

Plate 13, figures 23, 24, 29, 30

1824. Lucina cribraria Say, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 4, p. 147, pi. 13, fig. 1.
78 MOLLUSCA FROM MIOCENE AND LOWEfc PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1856. Lucina cribraria Say. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 58, pi. 18, figa 8, 9.

1863. Codakia cribraria Say (part). Conrad, Acad. Nat. Sci. 

Philadelphia Proc. for 1862, p. 577.

1903. Phacoides (Lucinisca) cribrarius Say (part). Ball, Wagner Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1372.

1904. Phacoides (Lucinisca) cribrarius (Say). Glenn, Maryland Geol. Survey, Miocene, p. 341.

1932. Phacoides (Lucinisca) cribrarius (Say). Mansfield, Florida Geol. Survey Bull. 8, p. 97, pi. 21, figs. 22, 23.

1937. Lucina- (Lucinisca) cribraria Say. Chavan, Jour, conchyliologie, vol. 81, p. 240, fig. 6.

Orbicular, convex, with numerous longitudinal costae, and distinct elevated concentric lines.

Shell with close-set, longitudinal, equal, granulated ribs, and 

more or less elevated, distinct, concentric lamellae; hinge margin 

obtusely and not prominently angulated at its anterior and 

posterior terminations; anterior margin with a dilated, slightly 

impressed, and not very obvious groove; lunule oblong-oval, 

very distinct, the edge near the beaks extending inward beside the 

primary teeth; lateral teeth very distinct, the posterior one 

placed nearly under the middle of the lunule; within crenate on 

the edge; posterior muscular Impression rectilinear.

Length half an inch, breadth u/£o of an inch.

Type locality: Maryland.—Say, 1824.

The figured right valve (U. S. Nat. Mus. 325536) is 

from the Yorktown formation, 5 miles northeast of 

Smithfield, Va., and measures 12.8 millimeters in height 

and 12.9 millimeters in width. The figured left valve 

(U. S. Nat. Mus. 325535), from the Yorktown formation 

at Yorktown, Va.r measures 10.0 millimeters in height 

and 10.6 millimeters in width.

Phacoides cribrarius is one of several species described by Say in 1824 which were collected, according 

to him, in Maryland by John Finch but which have not 

been noted by later observers. It is probable that they 

came from Virginia.

Shell of medium size, moderately compressed, subcircular in outline. Umbones subcentral, low and not very 

conspicuous, their apices acute and prosogyrate. Lunule, a small but profoundly excavated pit in front of 

the umbones. False lunule, or anterior dorsal area, 

depressed, elongate-cordate, defined by an incised line 

and an abrupt change in ornamentation; posterior dorsal area sharply defined by a depression of the valve and 

a conspicuous change in the character of the sculpture. 

Surface ornamented with about 30 radial lirae, low and 

flat-topped on the medial part of the disk, more elevated 

and arched toward the anterior and posterior margins; 

interspaces sublinear medially, widening somewhat distally; radials overriden by 12 to 18 sharply elevated, 

concentric lamellae, which, though completely fused 

medially, are somewhat broken up into concentric imbrications toward the distal margins; anterior dorsal 

area sculptured with & or 4 closely imbricated radials; 

sculpture on posterior dorsal area inconstant; usually 

4 or 5 low, crowded lirae, with 1 to 3 more prominent radials behind them; concentric lamellae fused 

except on the stronger marginal ribs, where they break 

up into free scales. Ligament opisthodetic, elongated,

inset. Anterior cardinal of right valve obsolete; posterior not very stout; anterior cardinal of left valve affected somewhat by the invagination of the lunule; posterior left cardinal very slender; posterior right and 

anterior left cardinals bifid only in the young. Anterior and posterior laterals distant, sharp little teeth 

cut off from the margin by a moderately deep sulcus; 

receiving pits of left valve small but moderately deep, 

their inner edges elevated into toothlike prominences. 

Anterior adductor impression very narrow, elongated 

to fully half the total altitude; posterior irregularly 

oval or quadrate. Inner margins strongly denticulated 

in harmony with the external costae.

No other coexistent Phacoides combines so vigorous 

a radial sculpture with so conspicuous a concentric ornamentation. Mansfield reports that Phacoides (Lucinisca) occurs in abundance in the Cancellaria zone of 

the Choctawhatchee formation and, less commonly, in 

the Ecphora zone.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; mouth of Bailey's Creek, Prince George 

County; Claremont Wharf (upper bed), Surry County; Zuni, 

Ferguson's Wharf (on the James River), and 5 miles northeast 

of Smitlifield, Isle of Wight County; a quarter to half a mile 

below Sycamore (on the Nottoway River), Southampton County.

North Carolina: Miocene, Yorktown formation, l1/^ to 2 miles 

above Branches Bridge, % mile below Branches Bridge, and 

Maddelys Bluff (on the Meherrin River), Northampton County; 

Murfreesboro, Hertford County; Halifax, y2 mile above the 

Atlantic Coast Line Railroad bridge (on Mr. Durham's farm), and 

Palmyra Bluff, Halifax County ; 2% miles northwest of Williamston (on Joseph Cherry's farm), Martin County, 15% miles above 

Bells Bridge and % mile above Bells Bridge, Edgecombe County. 

Duplin marl, 4 miles south of Clinton, Sampson County.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Duplin marl, Darlington, S. C.; Porters 

Landing on the SaA-annah River, Effingham County, Ga.

Submenus PARVILTICINA Dall

1901. ParvUucina Dall, U. S. Nat. Mus. Proc., vol. 23, p. 806. 

1937. ParvUucina Chavan, Jour, conchyliologie, vol. 81, p. 208.

Type by original designation: Lucina tenuisculpta Carpenter. 

Nunivak Island, Bering Sea, to the Coronado Islands.

Shell small, plump, often inequilateral; sculpture more or less 

reticulate but not muricate, teeth small, but all usually .present.— 

Dall, 1901.

Phacoides (Parvilucina) multilineatus (Tuomey and Holmes)

Dall

Plate 13, figures 34-37

1856. Lucina multilineata "Conrad". Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 61, pi. 18, figs. 16, 17.

3858. Lucina multilineata Emmons, North Carolina Geol. Survey 

Kept., p. 291 (name only).

1858. Lucina multilineata "Conrad." Holmes, Post-Pleiocene 

fossils of South Carolina, p. 29, pi. 6, fig. 6.

1901. Pftacoides (Parvilucina) crenella Dall, U. S. Nat. Mus. 

Proc., vol. 23, pp. 810, 825, pi. 39, fig. 2.

1903. Phacoides (Parvilucina) multilineatits Tuomey and 

Holmes. Dall, Wagner Free Inst. Sci. Trans., vol. 3, 

pt. 6, p. 1384.
PART 1. PELECYPODA

1932. Phacoides (Parvilucina) multilineata (Tuomey and 

Holmes). Mansfield, Florida Geol. Survey Bull. 8, p. 

101, pi'. 20, figs. 6, 7.

1937. ParvHudna multilineata Tuomey and Holmes. Chavan, 

Jour, conchyliologie, vol. 81, p. 210.

Shell orbicular, concentrically and closely ribbed, radiately 

striate.

This little fossil has the outline and general characters of 

L. crenulata, from which it can only be distinguished by the 

radiating lines, which give the shell a cancellated appearance.— 

Tuomey and Holmes, 1856.

Type locality: Waccamaw, S. C. Waccamaw formation.

A right and a left valve of different individuals 

(U. S. Nat. Mus. 325537) are figured. They were collected from the Waccamaw formation at Neills Eddy 

Landing on the Cape Fear River, N. C. The right valve 

measures 6.5 millimeters in height and 6.6 millimeters 

in width; the left valve measures 7.5 millimeters in 

height and 7.3 millimeters in width.

Tuomey and Holmes, by a happy blunder, identified 

their species with L. multilineata of Conrad. Conrad's 

form was not named "muttiUneata" but "multtstriata" 

and it was later relegated to subspecific rank under 

P. trisuLcO'tus.

Shell small, globose. Outline roughly circular, the 

dorsal margins forming a chord of the circle; lateral 

margins often a little contracted by the depression of 

the dorsal areas. Umbones central, moderately inflated; 

their apices acute and prosogyrate. Lunule small, 

smooth, cordate, depressed, but not excavated. Anterior and posterior dorsal areas defined by a slight depression of the valve, a very low and obscure, radial 

fold, and an abrupt disappearance of the radial sculpture. Surface ornamented with sublinear radiations, 

separated by interradials of scarcely greater width; 

radials obsolete in the umbonal region; concentric lirae 

very fine, overriding the radials and minutely cancellating them. Ligament opisthodetic, mounted on a linear 

nymph. Anterior cardinal of right valve almost obsolete; posterior subumbonal, robust, cuneiform; laterals 

vigorous; hinge of left valve armed with a moderately 

strong, anterior cardinal, a simple, compressed, posterior cardinal, and deep grooves for the reception of the 

strong right laterals. Adductor muscle impressions 

small, a little above the median horizontal. Inner margins crenulated in harmony with the external radials, 

much finer on the dorsal areas than on the intermediate 

disk.

Parvilucina multilineatus is larger and more inflated 

than Phacoides crenulatus, the only species with which 

it might be confused. The radial sculpture is stronger 

and more uniform than in the latter, and the concentric 

sculpture is more feeble and more inconstant.

The species does not appear until almost the close of

the Miocene. It is, however, abundant and widely distributed in the Oancellaria zone of the Choctawhatchee 

formation and is present in the Area zone.

Distribution: Virginia: Miocene, Yorktown formation, 1% 

miles northeast of Suffolk, Nansemond County.

North Carolina: Miocene, Yorktown formation, 100 yards below Bells Bridge on the Tar River, Edgecombe County; Tar 

Ferry on Wiccacon Creek (opposite Harrellsville), Hertford 

County; Rock Landing on'the Neuse River, Craven County. 

Duplin marl, Natural Well and 1% miles north of Magnolia, 

Duplin County; 2 miles below Luniberton and 4 to 5 miles below 

Lumberton, Robeson County. Pliocene, Waccamaw formation, 4 

miles south of Elizabethtown (on Hammond Creek) and Walkers 

Bluff (on the Cape Fear River), Bladen County; Lake Waccamaw, Cronly (% mile east of the factories), and Neills Eddy 

Landing (3 miles north of Cronly), Columbus County; Wilmington, New Hanover County.

Outside distribution: Miocene, Duplin marl, Porters Landing, 

Effingham County; Brunswick River bed, Brunswick, Ga. Choctawhatchee formation, northern Florida. Pliocene, Waccamaw 

formation, Waccamaw and Tillys Lake, Horry County, S. C. 

Caloosahatchee marl, Nashua and % mile above the Atlantic 

Coast Line Railroad bridge over the St. Johns River, Putnam 

County, Fla.; De Leon Springs, Volusia County, Fla.; Sanford, 

Seminole County, Fla.; Caloosahatchee River, Shell Creek, and 

Myakka River, Fla. Croatan sand, Croatan beds, Craven County, 

N. C. Pliocene (?), Charlton formation, Orange Bluff, St. Marys 

River, Nassau County, Fla. Pleistocene, Simmons Bluff and 

Wadmalaw Sound, S. C.; Rose Bluff, St. Marys River, Nassau 

County, Fla.; Orient, Hillsborough County, Fla.; Manatee Station and North Creek near Osprey,-Manatee County, Fla.; Kissimmee well (at a depth of 96 feet), Osceola County, Fla.; Eau 

Gallie, Brevard County, Fla.; Labelle, Hendry County, Fla. 

Recent, (?) Indian Pass, Fla., to Horn Island, Miss., in less than 

50 fathoms.

Family DIPLODONTIDAE ,

Genus DIPLODONTA Bronn 

1831. Diplodonta Bronn, Italiens Tertiar-Gebilde, p. 9.

Type by subsequent designation (Herrmannsen, Indicis generum Malacozoorum, vol. 1, p. 392) : Venus lupina Brocchi. 

Miocene and Pliocene of the Piedmont of Italy.

Shell equivalve, not gaping, subcircular, the beaks 

subcentral and not prominent. Lunule and escutcheon 

not defined. External surface smooth or incrementally 

sculptured. Ligament chiefly external, supported on. 

marginal nymphs. Hinge of right valve armed with 

a simple anterior and a bifid posterior cardinal; hinge 

of left valve armed with a bifid anterior and a simple 

posterior cardinal, so that in the closed valves the two 

outer cardinals are simple, the two inner ones bifid. 

Laterals absent. Adductor impressions oval, the anterior longer and narrower than the posterior. Pallial 

line entire. Inner margins of valves smooth.

The genus is first noted in the Cretaceous; from that 

time on it has constituted one of the less conspicuous 

elements in the bivalve faunas. The forty-odd Recent 

species have a wide distribution in the warmer waters 

of the globe.
MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Diplodonta caloosaensis Dall

Plate 14, figures 40, 41

1900. Difrtod&tota caloosaensis Dall, Wagner Free Inst. Sci. 

*Trans., vol. 3, pt. 5, p. 1188, pi. 44, fig. 16.

Shell large, moderately inflated, sculptured with somewhat 

irregularly prominent incremental lines; beaks low, pointed, 

inconspicuous; anterior end shorter, smaller, evenly rounded 

into the evenly arcuate base; posterior end squarish, longer, 

larger, more inflated; in the young the form is even more 

inequilateral and sometimes rounded trigonal with the anterior 

end attenuated; hinge line short, with hardly any hinge plate; 

ligamentary groove sharp, but the nymph not prominent; teeth 

and scars normal. Altitude 25, latitude 27, diameter 17 millimeters.

This species is larger and less equilateral than D. Leana; 

specimens of the same size are less inflated. It resembles 

D. punctata Say which is a smaller shell, but has not the 

microscopic surface sculpture.—Dall, 1900.

Holotype, a left Valve: U. S. Nat. Mus. 112865.

Type locality: Caloosahatchee River, Fla. Caloosahatchi marl.

Dimensions of figured specimen: Height 20.6 millimeters, width 22.3 millimeters, convexity 6.5 

millimeters.

Figured specimen, a left valve: U. S. Nat. Mus. 

325553.

Locality of figured specimen: Neills Eddy Landing, 

3 miles north of Cronly, Columbus County, N. C. 

Waccamaw formation.

The figured shell is decidedly heavier than Dall's 

holotype, but the differences are probably no more than 

individual. The Waccamaw species closely resembles 

the St. Marys form, D. leana eoleana, which is larger 

and less inflated than the Yorktown species D. leana. 

D. caloosaensis is less evenly rounded posteriorly than 

D. leana eoleana and more strongly upcurved along the 

anterior ventral margins, but the shells, if they occurred 

within the same area and formation, would be difficult 

to separate.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear River, Bladen County; 

Neills Eddy Landing on the Cape Fear River, Columbus County.

Outside distribution: Pliocene, Waccamaw formation, Waccamaw River, S. C. Caloosahatchee marl, Calossahatchee 

Siver, Fla.

Diplodonta leana Dall

1846. Psammocola lucinoides H. C. Lea, Am. Philos. Soc. Trans.,

new ser., vol. 9, p. 239, pi. 34, fig. 16. Not Diplodonta,

lucinoides Deshayes, 1824. 

1863. Psammocola? htcinoides H. C. Lea. Conrad. Acad. Nat.

Sci. Philadelphia Proc., for 1862, p. 573. 

1900. Diplodonta leana Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p. 1187.

P. testa suborbiculari, pene aequilaterali, postic^ et antice 

rotundata convexa, tenui, striata; striis concentricis, minimis; 

natibus prominentibus, subrectis; valva sinistra dentibus duobus 

cardinalibus, quorum unus bifidus, lateralibus nullis.

Shell suborbicular, almost equilateral, rounded anteriorly and 

posteriorly, convex, thin, striate; striae concentric, very small; 

beaks prominent, nearly straight; left valve with 2 cardinal 

teeth, i of which is bifid, and no lateral ones.

Diameter 0.15, length 0.31, breadth 0.35 of an inch.

Type locality: Petersburg, Dinwiddie County, Va.—H. C. 

Lea, 1846.

Dall's leana is nothing more than a replacement 

name for the preoccupied lucinoides of H. C. Lea.

Diplodonta leana Dall s. s. possesses none of the more 

striking features that characterize the coexistent Diplodontas. It is larger and much leNss globose than D. 

nucleiformis (Wagner) ; is smaller, thinner, more circular, and more inflated than D. acclinis (Conrad); 

is smaller, thinner, and less inflated in the umbonal 

region than D. caloosaensis Dall; and lacks the diagnostic shagreened surface of D. soror C. B. Adams.

Distribution : Virginia: Miocene, Yorktown formation, Petersburg, Dinwiddie County; Cobham Bay, Surry County; 2% 

miles northwest of Suffolk and 1 mile northeast of Suffolk, 

Nansemond County.

Norh Carolina: Miocene, Duplin marl, 1% miles northeast 

of Fairmont, Robeson County.

Diplodonta leana eoleana Gardner, n. subsp.

Plate 14, figures 37, 38

Shell of moderate dimensions, subcircular and rather 

strongly inflated for the group. Umbones scarcely interrupting the broad arc of the dorsal margins, the 

tips acute and turned toward each other, subcentral. 

Anterior end of shell broadly and obscurely truncate, 

the posterior portion broadly rounded from the umbones to the base. Incremental fairly strong and regular. Ligament groove deep. Dentition delicate but 

normal; two divergent cardinals in each valve, the pos-H 

terior right and the anterior left cardinals deeply sulcate, the anterior right and posterior left cardinals thin 

and laminar. Adductor scars elongated, placed well 

up under the dorsal margins. Margin of mantle attachment ragged. Pallial line simple, fairly close to 

the base.

Dimensions of holotype: Height 18.0 millimeters, 

width 19.1 millimeters, convexity 5.5 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325556.

Type locality: Urbanna on the Rappahannock River, 

Middlesex 'County, Va. St. Marys formation.

The St. Marys subspecies differs from Diplodonta 

leana from the Yorktown formation in the larger, heavier, and relatively higher and less inflated shell. It 

closely resembles the Waccamaw and Caloosahatchee 

species, D. caloosaensis Dall, but it is broader and a 

little less produced anteriorly and more evenly rounded 

posteriorly.

The subspecies has a fairly good representation at 

the single locality from which it has been reported.
PART 1. PELECYPODA 81

Section PHLYCTIDERMA Ball

1899. Phlyctiderma Ball, Jour, conchology, London, vol. 9, p. 244.

Type by original designation: Diplodonta semiaspera Philippi. 

Recent from Hatteras to Rio de Janeiro.

Shell like Diplodonta but with the surface more or less punctate or pustulate.—Ball, 1899.

Diplodonta (Phlyctiderma) soror (C. B. Adams)

Plate 14, figures 42, 43

1852. Lucina soror C. B. Adams, Contr. conchology, N.O. 12, p. 247. 

1858. Lucina* Mawahensis Holmes, Post-Pleiocene fossils of

South Carolina, p. 29, pi. 6, fig. 5. 

1900. Diplodonta soror O. B. Adams. Ball, Wagner Free Inst.

S'ci. Trans., vol. 3, pt. 5, p. 1188.

L. t. suborbiculari; margine superiore antice et postice declivi, 

inferiore antice subarcuatft ; cinereoalbidft; microscopice creberrime punctulata; striis concentricis exilissimis creberrimis; umbonibus prominentibus; apicibus subobliquis; lunuia minutissimft; limbo simplici; dentibus lateralibus obsoletis. Long. 19.6 

millim., alt. 18 millim., lat. 12.7 millim — C. B. Adams, 1852.

Type locality: Kingston Harbor, Jamaica. Living.

Shell thin, inflated, suborbicular, and approximately 

equilateral, but somewhat flattened or obscurely carinate posteriorly. Umbones central, inconspicuous, the 

tips incurved and prosogyrate. Posterior dorsal margin a little oblique and slightly depressed, broadly 

rounded or obscurely truncate laterally. Anterior 

dorsal margin continuous with the convex lateral margin. Base line strongly arcuate. External surface 

shagreened by microscopic punctae, which are imperfectly radial in arrangement and are largest and 

most numerous on the posterior slope. Ligament 

external, opisthodetic. Nymph short, inconspicuous; 

outer margin delimited by a moderately deep groove. 

Hinge normal, delicate; posterior cardinal of right 

valve and anterior cardinal of left valve deeply sulcated; anterior cardinal of right valve and posterior 

cardinal of left valve simple and laminar; hinge 

strengthened by the grooving of the dorsal margins. 

Adductor impressions usually irregular, subequal, 

submedian in position. Pallial line simple, rather 

near the ventral margin.

The figured left valve (U. S. Nat. Mus. 325555) 

from the Duplin marl at the Natural Well, N. C., 

measures 12.3 milimeters in height and 12.7 millimeters 

in width.

Diplodonta soror is characterized by the more or less 

pronounced posterior flattening and by the shagreened 

external surface. The single left valve from the Duplin marls near Magnolia is a little more elevated than 

the normal form but agrees perfectly in all other 

characters. The species has also been found in the 

Waccamaw formation.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well and 1^ mile north of Magnolia, Duplin County. Pliocene, 

Waccamaw formation, Neills Eddy Landing, 3 miles north of 

Cronly, Columbus County.

Outside distribution: Pleistocene, Ashley River and Simmons 

Blur, Wadmalaw Sound, S. C. Recent, Tortugas to Texas and 

south to Jamaica and the Antilles in less than 50 fathoms.

Superfamily Leptonacea

Family Leptonidae 

Genus ERYCINA Lamarck

1805. Erycina Lamarck, Mus. histoire nat. Annales, vol. 6, 

p. 413.

Type by subsequent designation (Stoliczka, Geol. Survey 

India, Mem., Palaeontologia Indica, Cretaceous fauna of southern India, vol. 3, p. 263, 1871) : Erycina pelludda Lamarck. 

Calcaire grossier of the Paris Basin.

The earliest designation was probably that of Anton, 

Verzeichniss der Conchylien^ p. 6, 1839. However, the 

species designated by Anton, Erycina elliptical Deshayes, is a Diplodonta; and as the confusion resulting 

from the acceptance of E. elliptic^ as the type would be 

very great, a request has been made to set aside the 

rules so that E. pellucida may be retained as the 

genotype of Eryaina.

Shell small, thin, elongate-oval, usually subequilateral. Surface usually smooth and sometimes with 

concentric or still more rarely with a radial sculpture. 

External ligament feeble; internal ligament lodged in 

a triangular resilial pit behind the umbones and near 

the dorsal margin. Cardinals minute, subumbonal, 1 

or 2 in each valve; strong laminated laterals developed 

both in front of and behind each umbo. Adductor 

impressions small, oval. Pallial line entire or slightly 

sinuated.

The genus apparently both originates and culminates 

in the Eocene. In the Paris Basin alone 47 species 

are known. In North America, although Erycina is 

most abundantly represented in the Gulf Eocene, it 

also occurs throughout the Tertiary section of the east 

coast.

.Erycina carolinensis Dall

Plate 14, figure 9

1900. Erycina carolinensis Ball, Wagner Free Inst. Sci. Trans., 

vol. 3, pt. 5, p. 1145, pi. 44, fig. 3.

Shell large for the genus, inequilateral, somewhat compressed, 

elongated, the anterior end produced, rounded, the posterior end 

shorter, downwardly arcuated; base nearly straight, slightly 

insinuated near the middle, corresponding to a slight mesial 

constriction of the shell; anterior dorsal margin nearly parallel 

with the base; posterior declining to a rounded point at its 

junction with .the base; beaks small, low, pointed; surface with 

rather strong, irregular, concentric incremental lines but very 

little radial striation; hinge normal, the lamellae rather long, 

and the hook (or cardinal) small; resiliary groove deep and 

strong, elongated; interior of the valves smooth or faintly 

radially striated toward the margins; adductor scars high up, 

the anterior larger, the pallial line rather wide, somewhat 

irregular. Longitude 13.25, altitude 7, diameter 4 millimeters.

This is the largest and apparently the most common species 

of Erycina in the later Tertiary of the Carolinas. On occasional specimens a little faint radial striation may be observed 

under the shelter of the concrntric sculpture, but many speci-
82 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE' OF VIRGINIA AND NORTH CAROLINA

mens do not show it, and on none does it appear to cover the 

surface.—Ball, 1900.

The right valve (U. S. Nat. Mus. 115096), from Natural Well, Duplin County, N. C., is here designated the 

lectotype. The measurements are as follows: Height 

5.7 millimeters, width 9.0 millimeters, convexity 1.5 

millimeters. The dimensions given by Dall are those 

of the form from the Waccamaw formation of South 

Carolina, the type of a suspecies elongata.

The species varies rather widely in its relative proportions, in the location of the umbones, and in the 

configuration of its posterior end. The Duplin shells 

are generally higher than the Waccamaw forms, the 

umbones are more nearly central, and the arch of the 

posterior dorsal and lateral margins is more uniform. 

The elongation of some of the later and more southern 

specimens is so pronounced that the differences are 

recognized by a subspecific division.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well and 1^ miles north of Magnolia, Duplin County. Pliocene, 

Waccamaw formation, Lake Waccamaw, Columbus County.

Erycina carolinensis elongata Gardner, n. subsp.

Plate 14, figure 1

1900. Erycina carolinensis Dall (part), Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, p. 1145, pi. 44, fig. 22.

Shell large for the genus. Outline elongate-ovate, 

inequilateral. Umbones low, slightly posterior, prosogyrate. Anterior dorsal margin rectilinear and parallel with the horizontal base line; lateral margin 

broadly rounded; posterior dorsal margin oblique, 

merging gradually into the posterior lateral, which is 

obscurely truncated at right angles to the base line. 

Incremental sculpture uneven, obsolete on the umbones; 

faint, crowded radials similar to those developed in 

Erycina kurtzia Dall but less distinct.

Dimensions of holotype, a left valve: Height 7.5 

millimeters, width 12.7 millimeters, convexity 4.0 

millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325542.

Type locality: Neills Eddy Landing on the Cape 

Fear River, Columbus County, N. C. Waccamaw 

formation.

The subspecies elongata is separated from carolinensis s. s. because of the relatively greater width, the 

more posterior umbones, and the more oblique posterior 

dorsal margin. The subspecies seems to be particularly 

characteristic of the later and more southern faunas. 

It has been recognize.d not only in the Waccamaw of 

both the Carolinas but in the Caloosahatchee marl of 

Florida as well.

Distribution: North Carolina: Pliocene, Waccamaw formation, Neills Eddy Landing, 3 miles north of Cronly, Columbus 

County.

Outside distribution: Pliocene, Waccamaw formation, Waccamaw River, S. C. Caloosahatchee marl, Caloosahatchee 

River, Fla.

Genus BORNIA Pliilippi

1836. Bomia Philippi, Enumeratio molluscorum Siciliae, vol. 

1, p. 13.

Type by subsequent designation (Stoliczka, Geol. Survey 

India, Mem,, Palaeontologia Indica, Cretaceous fauna of southern India, vol. 3, p. 266) : Bornia, corbuloides Philippi. Recent 

in the Mediterranean.

The shell is moderately compressed, subtrigonal to 

transversely elliptical and subequilateral. The surface 

may be smooth or feebly rippled and faintly striate 

concentrically. There is a feeble external ligament and 

a subumbonal resilium. The dentition in the right 

valve includes an anterior and a more produced posterior lamina; in the left, two short anterior lamellae 

and a much longer posterior lamina. The pallial line 

is simple.

Bornia is recorded from the Eocene of the Paris 

Basin and from the Tertiary of eastern North America 

and the Gulf of Mexico. The Recent species are 

restricted largely to the Mediterranean.

Bornia triangula Dall

Plate 14, figures 2, 3, 4, 5,10

Kellia triangula H. C. Lea, Label in coll. Acad. Nat. Sci.

Philadelphia. 

1900. Bornia triangula, n. sp.?, Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 5, p. 1151. 

1904. Bornia triangula Dall. Glenn, Maryland Geol. Survey,

Miocene, p. 330, pi. 88, figs. 9a, 9b.

This is the most common fossil species of our Tertiary. 

It occurs quite plentifully sometimes and is readily distinguished from B. mactroides, as a rule, by its shorter, more 

triangular, and less fiexuous shell. The outline is quite uniform 

as a whole and the shell almost always easily separated from 

B. mactroides, for which reason I have retained Lea's unpublished name, though I do not feel wholly confident that both 

these forms may not eventually prove to be extremes of a single 

species.

Type locality: Petersburg, ya.—Dall, 1900.

Dimensions of paratypes, a right and a left valve of 

different individuals: Height 3.0 millimeters, width 3.3 

millimeters.

Paratypes, a right valve and a left valve of different 

individuals: U. S. Nat. Mus. 325547, from Yorktown, 

York County, Va. Yorktown formation.

Hinge concentrated; resilial pit moderately deep, 

subumbonal; anterior lamella of right valve pocketlike, 

thickening abruptly in front of the umbones, recurved 

and coalescent with the dorsal margin directly beneath 

the tips; posterior lamella subspinose medially; lamellae of left valve two, the one in front sharply bent and 

thickened at its umbonal end (thus simulating a true 

cardinal), the one behind slightly diverging and reduced to a cardinallike 'protuberance directly beneath 

the umbo; posterior lamella of left valve not so heavy 

as the'anterior, obscurely cuneiform, wedging out near 

the tips of the beaks.
PART 1. PELECYPODA 83

Bornia triangula JL>all is characterized by an outline 

that roughly approximates a rather high isosceles 

triangle, with the umbones at the apex, the ventral 

margin at the base. The species varies somewhat in 

general proportions and in the position and prominence of the umbones. The representatives from Yorktown are higher, as a rule, than those collected at either 

Petersburg, Va., or Natural Well, N. C. The outline 

of the Yorktown representatives is more inequilateral, 

the anterior dorsal margin somewhat contracted in 

front of the umbones, and the anterior slope perceptibly steeper than the posterior. The valve is consequently more narrow in front than behind, and the 

umbones are more conspicuous than in those forms that 

are not contracted anteriorly. The young of the 

species are so unlike the adults that they would certainly be considered distinct were they not found associated in an unbroken series. They are stout, convex, 

suborbicular little shells with rude, unformed hinges 

and heavy lamellae.

The representatives of the species in Virginia and 

North Carolina are not confusable with the broader, 

more angular B. mactroides of the Maryland fauna. 

B. rota of the Duplin and Waccamaw is smaller, more 

compressed, and more attentuated dorsally.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown and I1/! miles below Yorktown, York County; Petersburg, 

Dinwiddie County; Mr. Everet's farm near Benns Church, Isle 

of Wight County; 1% miles northeast of Suffolk and % mile 

below the Suffolk waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% miles 

below Tar Ferry on Wiccacon Creek, Hertford County; Colerain 

Landing on the Chowan River, Bertie County; Wilson, Wilson 

County; Rock Landing on the Neuse River, Craven County. 

Duplin marl, Natural Well and 1% miles north of Magnolia, 

Duplin County; Lumber ton (near the bottling works), Robeson 

County. Pliocene? Waccamaw formation, Walkers Bluff, Bladen 

County; Neills Eddy Landing (3 miles north of Cronly) and 

Lake Waccamaw, Columbus County.

Outside distribution: Miocene, Duplin marl, Darlington, S. C. 

Pliocene, Caloosahatchee marl, Caloosahatchee River and Shell 

Creek, Fla.

Bornia bladenensis Gardner, n. sp.

Plate 14, figures 11, 12

Shell thin, polished, strongly convex, oval, subequilateral. Umbones slightly anterior, inflated, incurved, 

prosogyrate at the tips, scarcely interrupting the low 

arch of the similar dorsal margins; lateral margins 

broadly and regularly curved; ventral margin straight 

medially, upcurved distally. Surface gently rippled 

by about a dozen feeble radial folds, strongest near the 

periphery, evanescing halfway to the umbones; external 

undulations reflected within. Hinge delicate. Eesilifer sublinear, oblique. Anterior lamella of right valve 

thickened beneath the umbo into a small but prominent 

cardinal hook; posterior lamella elongated, subspinose 

a little behind the middle; left valve not known.

Bornia bladenensis is represented by a single right 

valve that is apparently not full grown. The plication 

is so diagnostic, however, and so unlike any character 

exhibited by any of the coexistent species that it seems 

worth while to announce the form at once.

Dimensions of holotype: Height 3.9 millimeters, 

width 4.75 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325546.

Type locality: Walkers Bluff, Bladen County, N. C. 

Waccamaw formation.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff, Bladen County.

Family SPOETELLIDAE 

Genus SPORTELLA Deshayes

1858. Sportella Deshayes, Description animaux sans vertebres 

Bassin de Paris, vol. 1, p. 593.

Type by original designation: Psammotea dubia Deshayes. 

Calcaire grossier of the Paris Basin.

Shell small, thin, transversely elongate, slightly convex, subequilateral in the majority of species. Umbones low and inconspicuous. Neither lunule nor 

escutcheon defined. Surface smooth or feebly undulated by incrementals, occasionally sculptured with a 

submicroscopic radial striation. External ligament 

seated on elongate nymphs; internal lodged in oblique, 

subumbonal resilial pit. Dentition of right valve consisting of a strong, often recurved, posterior cardinal 

and a rudimentary anterior cardinal; hinge of left 

valve with two unequal, divergent cardinals, the anterior of which is stronger. Adductor impressions 

oval, subequal. Pallial line entire, often punctate. 

Inner margins smooth.

This is a genus of small and inconspicuous bivalves 

that inhabited the near-shore waters of Europe and 

America during Tertiary and Quaternary times.

Sportella constricta (Conrad) Dall 

Plate 14, figures 19, 20

1841. Amphidesma constricta Conrad, Am. Jour. Sci., 1st ser.,

vol. 41, p. 347, pi. 2, fig. 15. 

1843. Amphidesma constricta Conrad, Am. Assoc. Geologists

and Naturalists, vol. 1, p. 110, pi. 5, fig. 15.

1845. Amphidesma constricta Conrad, Fossils of the medial Tertiary of the United States, p. 76, pi. 43, fig. 10. 

1854. Syndosmya constricta, Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 7, p. 29. 

1863. Fabella, constricta Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, pp. 574, 586. [Monotype of Fabella.] 

1889. Lepton (Fabella) constricta Conrad. Dall, U. S. Nat.

Mus. Bull. 37, p. 48. 

1898. Sportella constricta Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 4, pi. 25, figs. 4, 4a. 

1900. Sportella constricta Conrad. Dall, idem, vol. 3, pt. 5, p.

1128. 

1932. Sportella constricta (Conrad). Mansfield, Florida Geol.

Survey Bull. 8, p. 107, pi. 21, figs. 14, 18.

Oblong, oval, ventricose; basal margin opposite the apex 

slightly contracted; end margins rounded; beaks nearest the
84 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

posterior extremity; fosset profound; cardinal teeth prominent, 

lateral teeth none.—Conrad, 1841.

Dimensions of figured specimens: Right valve, height 

6.0 millimeters, width 9.0 millimeters. Left valve, 

height 5.7 millimeters, width 9.0 millimeters.

Figured specimens: U. S. Nat. Mus 155730, from the 

Caloosahatchee River, Fla.

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl.

Shell heavy, slightly inequilateral, transversely oval 

to subquadrate. Umbones inconspicuous, prosogyrate, 

located a little behind the median line. Anterior end 

slightly contracted in front of the beaks; anterior 

dorsal margin nearly rectilinear and subparallel to the 

base; lateral margin broadly rounded. Posterior dorsal margin slightly oblique and reflected; posterior end 

a little shorter and more narrow than the anterior. 

Surface irregularly wrinkled by the incrementals. 

Hinge conspicuously robust. Ligamentary attachment 

opisthodetic, sublinear. Resilial pit oblique, deeply 

excavated. Right posterior and left anterior cardinals 

stout and conical; right anterior and left posterior 

cardinals rudimentary; cardinal fossets correspondingly deep. Adductor scars obscure, set well up toward the dorsal margin, the anterior a little higher 

than the posterior. Pallial line entire.

Sportella constricta (Conrad) differs from all its 

congeners by its subquadrate outline and by the vigor 

of its hinge. .

Distribution: North Carolina: Miocene, Duplin marl, Natural Well and 1% miles north of Magnolia, Duplin County. Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear 

River, Bladen County.

Outside distribution: Miocene, Choctawhatehee marl, northern Florida. Pliocene, Waccamaw formation, Tillys Lake, 

Horry County1, S. C. Caloosahatchee marl, Caloosahatchee 

River and Shell Creek, Fla.

Sportella calpix Gardner, n. sp.

Plate 14, figures 30, 39

Shell moder.ately convex in the umbonal region, compressed ventrally, often with a very broad and shallow 

medial depression. Outline transversely ovate, inequilateral. Umbones a little posterior, prosogyrate. 

Anterior end slightly contracted in front of the beaks; 

anterior dorsal margin obliquely truncated, lateral 

margin evenly rounded. Posterior dorsal slope more 

steep than the anterior, merging gradually into the 

broadly rounded lateral margin. Base horizontal. 

Surface concentrically striated with submicroscopic incrementals, most plainly visible toward the lateral 

margins; traces of a faint, distant, radial striation discernible on both the exterior and the interior of the 

valve. Ligament opisthodetic, lodged in a deep groove. 

Resilial pit oblique, profound. Posterior cardinal of 

right valve stout, subtriangular; anterior cardinal rudimentary ; anterior cardinal of left valve strong, conical;

posterior cardinal rudimentary. Adductor impressions 

obscure, apparently rather near the ventral margin. 

Pallial line entire.

Dimensions: Height 10.2 millimeters, width 14.7 millimeters, convexity 3.5 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325543.

Type locality: iy2 miles below Tar Ferry, on Wiccacon Creek, Hertford County, N. C. Yorktown 

formation.

Sportella calpix is most closely, allied to S. pelex 

Dall, from the Yorktown of Virginia. The latter is, 

however, a much smaller, relatively higher shell with 

a less produced and attenuated anterior end. The 

obliquity of the anterior dorsal margin separates S. 

calpix at once from S. constricta (Conrad) and S. waccamawensis, whereas the dissimilarity of the dorsal 

margins separates it from the more nearly equilateral 

S. petropolitana Dall.

Distribution: North Carolina: Miocene, Yorktown formation, 

Tar Ferry on Wiccacon Creek (opposite Harrellsville) and l1/^ 

miles below Tar Ferry, Hertford County; % to % mile above 

Edenhouse Point, Bertie County. Duplin marl, 1% miles northeast of Fairmont, Robeson County. Pliocene, Waccamaw 

formation, Walkers Bluff, Baden County.

Sportella gibberosa Gardner, n. sp.

Plate 14, figures 6, 7

Shell small, heavy for its size, moderately inflated, 

transversely ovate, inequilateral. Umbones subcentral, 

slightly posterior, prosogyrate. Anterior end contracted in front of the umbones; anterior dorsal slope 

rather gentle, merging gradually into the rounded lateral margin. Posterior dorsal margin obscurely 

arched; lateral margin broadly rounded. Base line 

straight. Incrementals distant and inconspicuous; 

traces of a radial striation faintly discernible on both 

the external and the internal surfaces. Hinge delicate. 

Ligament groove minute, opisthodetic; resilial pit 

oblique, moderately deep. Only the right posterior and 

left anterior cardinals developed and these not prominently. Anterior adductor impression elongated; posterior suborbicular, situated a little below the median 

horizontal. Pallial line entire.

, Dimensions of cotypes: Right valve, height 3.2 millimeters, width 4.5 millimeters. Left valve, height 3.3 

millimeters, width 4.5 millimeters.

Cotypes, a right and a left valve of different individuals: U. S. Nat. Mus. 325544.

Type locality: Walkers Bluff on the Cape Fear 

River, Bladen County, N. C. Waccamaw formation.

The slight contraction in the basal margin of the 

left valve of the type is an individual rather than a 

specific character. This small form recalls in outline 

and dimensions. Mactra clathrodon H. C. Lea. Because of its minute size and the delicacy of the hinge, 

it was at first considered to be the young of an unreported adult, but the relatively heavy shell and the
PART 1. PELECYPODA 85

crowding of the incrementals toward the ventral margin are evidences to the contrary.

The vaulting of the dorsal margin behind the umbones gives to the species a hunch-backed aspect that is 

characteristic.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear River, Bladen County; 

Neills Eddy Landing, 3 miles north of Cronly, Columbus County.

Sportella waccamawensis Gardner, n. sp.

Plate 14, figures 21, 22

Shell of moderate size, rather compressed, especially 

toward the ventral margin; outline Roughly ovate, 

rather angular, inequilateral. Umbones moderately inflated, prosogyrate, subcentral, or slightly posterior. 

Anterior end contracted in front of the umbones; dorsal 

margin slightly excavated; lateral margin squarely 

truncated. Posterior dorsal slope rather steep, merging gradually into the evenly rounded, lateral margin. 

Base horizontal. Surface sculptured with unequal, 

often exaggerated incrementals and with faint traces 

of rather distant radiating striations; interior of valve 

also faintly rayed. External ligament lodged in a 

groove behind the umbo; resilial pit deep and oblique. 

Right posterior and left anterior cardinals stout; other 

cardinals not developed; cardinal sockets moderately 

deep. Adductor impressions rather obscure, placed 

about halfway between the umbones and the base; anterior elongated, posterior subcircular. Pallial line 

entire.

Dimensions of holotype: Height 8.2 millimeters, 

width 13.5 millimeters, convexity 2.0 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325545.

Type locality: Walkers Bluff on the Cape Fear 

River, Bladen County, N. C. Waccamaw formation.

Sportella waccamwwensis differs from all its congeners by the configuration of the anterior part of its shell, 

outlined by the slightly excavated dorsal margin, the 

horizontal ventral margin, and the lateral margin truncated at right angles to the base. The young are relatively higher and less angular, and thus approach S. 

pelex Dall and S. calpix. The form has been reported 

from the Waccamaw formation only.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear River, Bladen County; 

Neills Eddy Landing, 3 miles north of Cronly, Columbus 

County.

Sportella compressa (H. C. Lea) Dall

Plate 14, figures 27-29

1846. Petricola compressa. H. C. Lea, Am. Philos. Soc. Trans., 2d

ser., vol. 9, p. 239, pi. 34, fig. 15. 

1863. Petricola compressa, H. C. Lea. Conrad, Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 576. 

1898. SporteUa compressa H. C. Lea. Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 4, pi. 25, fig. 3a.

1900. Sportella compressa H. C. Lea. Dall, idem, vol. 3, pt 5, 

p. 1130.

Shell very transverse, very inequilateral, subelliptical, compressed, posteriorly subtruncate, anteriorly rounded, thin, 

striate posteriorly and anteriorly; striae very small, concentric; basal margin straight; dorsal margin straight; beaks 

somewhat acute, prominent; teeth 2, small, divergent. Diameter 0.10, length 0.12, breadth 0.25 inch.

The concentric lines of growth are very small. They are 

visible on the anterior and posterior portions of the shell. On 

the central part they are obsolete, leaving it smooth. The 

teeth are small and unusually divergent for a Petricola.—H. C. 

Lea, 1846.

Figured specimen, a left' valve: Acad. Nat. Sci. Philadelphia 1596.

Type locality: Petersburg, Va. Yorktown formation.

Sportella compressa (H. C. Lea) is separated from 

/S. protexta (Conrad) by a heavier shell, by an elongate 

and oval rather than a sublanceolate outline, and by the 

absence of punctae on the external surface. No other 

of the coexistent Sportellas approaches it in the degree 

of transverse elongation.

Distribution: Virginia: Miocene, Yorktown formation, Petersburg, Dinwiddie County.

North Carolina : Pliocene, Waccamaw formation, (?) Walkers 

Bluff, Bladen County; Neills Eddy Landing, 3 miles north of 

Cronly, Columbus County.

Outside distribution: Pliocene, Waccamaw formation, Tillys 

Lake, Horry County, S. C. Caloosaliatchee marl, Caloosahatchee River, Fla. Croatan sand, Slocums Creek, Craven 

County, N. C. (Dall).

Family MONTACUTIDAE 

Genus MYSELIA Angas

1876 (July 24). Rochefortia Velain, Comptes rendus, p. 285 

(nomen ,nudum).

1877 (Aug. 1, fide Iredale). Mysella Angas, Zool. Soc. London 

Proc., p. 176.

1878 (not earlier than Nov. 12, fide Iredale). Rochefortia 

Velain, Archives de zoologie experimental et ge'ne'rale, 

vol. 6, p. 132.

Type by monotypy: Rochefortia australis, Ve"lain. St. Paul 

Island, South Indian Ocean.

1891. Mysella Angas. E. A. Smith, Annals and Mag. Nat. History, 6th ser., vol. 8, p. 235.

1899. Mysella Dall, U. S. Nat. Mus. Proc., vol. 21, pp. 876, 881.

1900. Rochefortia Dall, Wagner Free Inst. Sci. Trans., vol. 3,

pt. 5, p. 1157. 

1924. Mysella Angas. Iredale, Linnean Soc. New South Wales

Proc., vol. 49, p. 207.

Type by monotypy: Mysella anomala Angas. Recent off the 

southeastern Australian shores.

Dall, 1900J has given a comprehensive discussion of 

the group. He failed to recognize the nudity of Rochefortia Velain, 1876; and apparently the priority of 

Mysella Angas has been established by Iredale. Many 

of the recent species of Rochefortia are commensal with 

Crustacea.
86 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Mysella stantoni (Dall) Gardner

Plate 14, figure 8

1900. Rochefortia stantoni Dall, Wagner Free Inst. Sci. Trans., 

vol. 3, pt. 5, p. 1160, pi. 43, fig. 11.

Shell minute, convex, elongate-ovate, quite inequilateral, the 

anterior end much longer; surface with faint incremental lines, 

polished; dorsal margin arcuate in front, descending behind the 

umbo; ends rounded, an oblique nearly straight bit of margin 

intervenes between the posterior rounded end and the areua'te 

base as if a little of the edge had been shaved off; beaks low, 

hinge with small lamellar teeth, the anterior nearly twice as 

long as the posterior, resiliary notch small; adductor scars 

high, rather large, and distinct; margin simple, entire. Longitude 3.6, altitude 2.4 [2.2], diameter 1.5 [0.8] millimeters— 

Dall, 1900.

Holotype, a right valve: U. S. Nat. Mus. 115102.

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl.

This minute, ovate, inequilateral form is the most 

individual of any of the east coast Tertiary Mysellas. 

It is characterized by a transversely elliptical outline 

and a simple laminar dentition.

The species was named in honor of Dr. T. W. Stanton, who retained his interest in and his command of 

the Lower Cretaceous faunas through many years of 

duty in high administrative positions.

Distribution: Virginia: Miocene, Yorktown formation, Sycamore on the Nottoway River, Southampton County. 

• North Carolina: Miocene, Duplin marl, Natural Well and 1% 

miles north of Magnolia, Duplin County. Pliocene, Waccamaw 

formation, Neills Eddy Landing, 3 miles north of Cronly, Columbus County; Wilmington, New Hanover County.

Mysella bladenensis Gardner, n. sp.

Plate 14, figures 17, 18

Shell thin, minute, moderately compressed, elongateoval, slightly contracted anteriorly. Umbones low, almost level with the anterior dorsal margin, incurved, 

placed about two-thirds of the distance back toward the 

posterior margin. Anterior dorsal margin rectilinear, 

parallel with the horizontal base line; lateral margin 

evenly rounded; posterior end very short, slightly contracted behind the umbones; rounded laterally. Incremental sculpture strong, equally conspicuous on all 

parts of the external surface. Radial sculpture discernible under high magnification, possibly adventitious 

as in so many of the species of Leptonacea. Resilifer 

concealed beneath the tip of the umbo. Dental lamellae 

short, equal, divergent, subspinose near their ventral 

margins. Adductor impressions and pallial line 

obscure.

Dimensions of holotype: Height 3.0 millimeters, 

width 4.5 millimeters, convexity 1.0 millimeter.

Holotype, a right valve: U. S. Nat. Mus. 325550.

Type locality: Walkers Bluff, Bladen County, N. C. 

Waccamaw formation.

Mysella bladenensis is allied to M. stantoni (Dall) 

and to M. velaini. It does not, however, exhibit the 

peculiar oblique truncation of the posterior ventral 

margin that characterizes M. stantoni (Dall), and it 

differs furthermore in the similar anterior and posterior 

dental laminae. M. velaini is a less regular, more 

elevated species.

Distribution: North Carolina : Pliocene, Waccamaw formation, 

Walkers Bluff, Bladen County.

Mysella velaini Gardner, n. sp.

Plate, 14, figures 15, 16

Shell minute, moderately compressed, elongate-ovate, 

inequilateral. Umbones low, inconspicuous, rising only 

a little above the level of the dorsal margin, located 

about two-thirds of the distance toward the posterior 

margin. Posterior end very short, faintly depressed, 

broadly and evenly rounded; anterior end much produced, the dorsal margin rudely parallel to the base, 

the lateral margin evenly rounded; base line horizontal 

medially. Incremental sculpture strong, irregular, 

most conspicuous anteriorly. Resilifer concealed beneath the tip of the umbones. Dental laminae short, 

subequal, feeble but distinct, subspinose near their 

ventral extremities. Adductor impressions and pallial 

line obscure.

Dimensions of holotype: Height 3.0 millimeters, 

width 4.2 millimeters, convexity 0.9 millimeter.

Holotype, a right valve: U. S. Nat. Mus. 325548.

Type locality: Walkers Bluff on the Cape Fear River, 

Bladen County, N. C. Waccamaw formation.

This odd little ovate form is characterized by the 

obliquely elliptical outline, the relatively strong incremental sculpture, and the feeble dentition. It is more 

elevated and less regular than M. bladenensis, the only 

form that approaches it in general outline. It is named 

in honor of M. Velain, the author of the genus 

Rochefortia.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff, Bladen County; Neills Eddy Landing, 3 

miles north of Cronly, Columbus County.

Mysella majorina Gardner, n. sp.

Plate 14, figures 13, 14

Shell moderately large for the genus; transversely 

ovate; moderately compressed, inequilateral. Umbones 

low and inconspicuous, a little behind the median horizontal, slightly bulbous at their apices. Lunule and 

escutcheon not defined. Anterior end produced, the 

dorsal slope very gentle, almost rectilinear; the lateral 

margin broadly rounded. Posterior end relatively 

short and narrow; the dorsal margin descending more 

rapidly posteriorly than anteriorly; the lateral margin 

obtusely pointed. Base line feebly arcuate. External 

surface polished, sculptured only with microscopically 

fine and close concentric striations. Ligament entirely
PART 1. PELECYPODA 87

internal, lodged in a subumbonal resilial pit concealed 

beneath the apices of the umbones. Hinge lamellae of 

right valve short, equal, divergent, subspinose distally; 

margins of left valve on each side of the umbones 

beveled to fit into the sockets between the lamellae and 

the dorsal margins of the right valve. Interior of 

valve faintly radiate. Adductor muscle impressions 

and pallial line obscure.

Dimensions of cotypes: Right valve, height 2.7 millimeters, width 4.0 millimeters, convexity 0.6 millimeter. 

Left valve, height 2.7 millimeters, width 4.1 millimeters, convexity 0.5 millimeter.

Cotypes, a right and a left valve of different individuals : U. S. Nat. Mus. 325549.

Type locality: Neills Eddy Landing on the Cape 

Fear River, N. C. Waccamaw formation.

Mysella majorina is conspicuous among its congeners 

for its narrow, obtusely pointed, posterior extremity. 

It is known only from the type locality.

Distribution: North Carolina: Pliocene, Waccamaw formation* Neills Eddy Landing (3 miles north of Cronly) on the 

Cape Fear River, Columbus County.

Genus ALIGENA H. C. Lea

1846. Aligema H. C. Lea, Am. Philos. Soc. Trans., 2d ser., vol. 9, 

p. 238.

Type by subsequent designation (Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, p. 1175) : Aligena striata H. C. Lea. Miocene (Yorktown) from Petersburg, Va.

Shell equivalve; subequilateral, closed posteriorly and anteriorly ; hinge with one cardinal tooth and a long shallow 

sulcation under the beaks.

The cardinal tooth is, in general, rather small. The sulcus 

appears to have received the ligament. It commences at the 

beak and runs obliquely past the dorsal margin into the cavity 

under the beak. As I possess only odd valves of both the following species, I am unable to determine whether the shell is 

equivalve or not. * * * I have called the genus Aligena, 

one of the surnames of Venus, from ite resemblance to Erycina, 

also an appellation of that goddess.—H. C. Lea, 1846.

Aligena is known by its rounded-trigonal convex 

shell, obliquely elongated resilifer, and single subumbonal cardinal.

The genus has representatives in the Tertiary deposits of the east coast and of the Paris and Vienna 

Basins and still persists in the cooler waters of the 

Atlantic.

Two species were cited by Lea in his original description of Aligena. The first, designated as the type 

of the genus, is A. striata. The second, A. laevis (pi. 

14, figs. 24-26), differs from the first in the much more 

produced and less conical cardinal tooth and in the 

thickened, and, modified dorsal margins. Dall suggested that it is "apparently a species of Fulcrella" but 

it is distinct from the American species assigned to 

that genus. Only the holotype, a right valve, has 

been recorded.

Aligena chowanensis Gardner, n. sp.

Plate 14, figures 31, 32

Shell small, moderately convex, elevated, roughly 

trigonal, inequilateral. Umbones inflated, subcentral, 

strongly prosogyrate. Dorsal and lateral areas not 

differentiated. Anterior end contracted and slightly 

excavated in front of the umbones; rounded and somewhat produced laterally. Posterior end obscurely convex, rounding rather abruptly into the feebly arcuated 

ventral margin. Surface sculptured with fine, irregular, discontinuous striations; resting stages conspicuous, occurring at fairly regular intervals, 4 in all. 

Ligament internal; resilifer narrow, obliquely elongated, deeply submerged beneath the umbones. Cardinal 

broken away; scar, of moderate size, just below the tip 

of the beak. Adductor impressions and sinus obscure.

Dimensions of holotype: Height 4.7 millimeters, 

width 4.7 millimeters, convexity 1.5 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325551.

Type locality: The single right valve on which the 

species is founded was collected in the marls of the 

Yorktown formation at Colerain Landing, on the 

Chowan River, Bertie County, N. C.

The peculiar concavo-convex outline of the anterior 

and posterior ends, the attenuated dorsal region and 

the strong resting stages are not displayed by any of 

the coexistent Aligenas and vaguely suggest some of 

the small Phacoides, notably P. trisulcatus Conrad.

Distribution: North Carolina: Miocene, Yorktown formation, 

Colerain Landing, Bertie County.

Aligena rhomboidea Gardner, n. sp.

Plate 14, figure 23

Shell rather large for the genus, strongly convex, 

slightly depressed posteriorly, inequilateral, roughly 

rhomboidal. Umbones placed a little behind the 

median line, inflated, feebly prosogyrate. Anterior 

dorsal margin rectilinear; subparallel with the base, 

extending a little beyond it; lateral margin broadly 

rounded. Posterior end shorter than anterior and 

much narrower; posterior dorsal slope steep, roughly 

parallel with the anterior lateral margin. Surface 

badly worn; sculpture limited to incrementals that were 

probably rather strong. Ligament internal. Resilifer 

narrow, elongated, deeply submerged beneath the cardinal margin. Cardinal tooth solitary, a small, 

rounded protuberance directly below the tip of the 

umbo. Interior polished. Adductor impressions and 

pallial line obscure.

Dimensions of holotype: Height 7.8 millimeters, 

width 8.8 millimeters, convexity 2.3 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325552.

Type locality: Duplin marl at the Natural Well, 

Duplin County, N. C.
88 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Aligena rhomboidea does not seem to be closely related 

to any of the coexistent Aligenas. It is larger than 

any except the largest of the A. aequata; the rhomboidal outline is peculiar to the species, and the cardinal 

tooth is relatively smaller than in any of its congeners. 

Only a single left valve was collected.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well, Duplin County.

Superfamily CHAMACEA 

Family CHAMIDAE

The Chama group offers one of the best examples of 

the effect of habitat on the outline of valves and on the 

development of hinge dentition. True Chama is 

attached by the left valve, Pseudochama by the right, 

but in both genera the resulting form is the same—a 

heavy, concave, often cornucopia-shaped attached valve 

and a thinner, flatter free valve. The Mesozoic Rudistids of all the sessile bivalves present the most striking 

shell modifications, but the same tendency may be 

observed to a lesser degree in the Ostreas.

Genus CHAMA Linnaeus

1758. Chama Linnaeus (part), Systema naturae, 10th ed., p. 601. 

1919. Chama Odhner, K. svenska vetensk. akacl. Handl., Band 

59, Nr. 3, p. 75.

Type by subsequent designation (Schmidt, 'C. F., Versuch 

tiber die beste Einricht, etc., pp. 63, 177, 194, Gotha, 1818) : 

Chama lazarus Linnaeus. Recent in the Indian Ocean.

The apices are twisted to the right, and the left valve 

is attached to the substratum.

Chama striata Emmons

Plate 13, figures 12-15

1858. Chama striata Emmons, North Carolina Geol. Survey 

Kept, p. 288, fig. 211.

1863. Chama striata Emmons. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 576.

1903. Chama striata Emmons. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 6, p. 1401.

1932. Chama striata Eminons. Mansfield, Florida Geol. Survey 

Bull. 8", p. 91, pi. 16, figs. 8,10.

Shell small, ovate, rather thick for its size; lower valve distinctly striate. Usually found in the hollow or inside of the 

univalves.—Emmons, 1858.

Habitat, North Carolina.

Right and left ^valves of different individuals from 

the Waccamaw formation at Neills Eddy Landing on 

the Cape Fear River, N. C., have been figured. The 

right valve (U. S. Nat. Mus. 325541) measures 17.0 

millimeters in height and 18.5 millimeters in width. 

The left valve (also U. S. Nat. Mus. 325541) measures 

24.0 millimeters both in height and in width.

Shell inequivalve, inequilateral, small, rather compressed, attached by the lower left valve, which is 

irregular in outline, moderately deep, and medially depressed; upper right valve flattened except near the 

apex of the umbo, irregular in outline, obscurely bi- or 

tri-lobate. Surface of lower valve sculptured with 

about half a dozen overlapping lamellae, transversely 

puckered, the free edges occasionally flaring into subspinose processes, which occur most commonly along 

the ridges that outline the medial depression and on 

the posterior slope; sculpture of upper valve much 

finer, the laminae sometimes breaking into free spines 

along the summits of the radial ridges and near the 

posterior margin, usually gathered into closely proximate and closely appressed tubuli. Ligament groove 

narrow, moderately deep. Dental socket of left valve 

narrow, oblique, undercutting the dorsal margin; tooth 

laminar, slightly crescentic, transversely grooved dorsally; dental process of right valve rather slender, 

sharp; dorsal margin grooved beneath the umbones to 

correspond to the sulcations of the tooth of the left 

valve. Adductor impressions elongate-oblong, submedial, the anterior terminating just in front of the 

dental lamina. Pallial line simple. Inner margins 

finely and closely crenate.

Chama striata Emmons is a smaller and more compressed species than its less frequent congener, C. con-^ 

gregata Conrad. The medial depression of C. striata 

is a diagnostic character; the lamellae on the left valve 

are fewer, and the spines are fewer and stronger than 

those of C. congregata. The right valve is more flattened than in C. congregata and the radial sculpture 

more delicate except for an occasional strongly developed spine. In Florida C. striata has been reported 

only from the Cancellaria zone of the Choctawhatchee, 

whereas C. congregata occurs not only in the Ccmcellaria 

zone but also in the underlying Ecphora zone. C. congregata has been reported by Olsson from the Gatun 

of Costa Rica. C. involuta Guppy of the upper Miocene mid-American fauna is a smaller shell with a 

more highly inflated left valve and a more closely 

plicate sculpture.

Distribution: Virginia: Miocene, Yorktown formation, Benns 

Church, Isle of Wight County.

North Carolina: Miocene, Yorktown formation, Rock Landing, Craven County. Duplin marl, 2l/2 miles south of Clinton, 

4 miles south of Clinton, Sampson County; 3 miles northeast 

of Warsaw, Natural Well, 1% miles north of Magnolia, and 

Frank Wilson's and W. H. Kornegay's marl pits (near Magnolia), Duplin County; Lumber ton (near the bottling works), 

2 miles below Lumberton, 4 to 5 miles below Lumberton, 1% 

miles northeast of Fairmont (Ashpole), and at Fairmoint, Robeson County. Pliocene, Waccamaw formation, Lake Waccamaw, 

Neills Eddy Landing, Columbus County; Wilmington, New 

Hanover County.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Pliocene, Waccamaw formation, Tillys Lake, 

Horry County, S. C. Caloosahatchee marl, Caloosahatchee 

River and Shell Creek, Fla.
PART 1. PELECYPObA 89

Genus FSEUDOCHAMA Odhner

1917. Pseudochama Odhner, K. svenska vetensk. akad. Handl., 

Band 52, No. 16, p. 30.

Type by monotypy: Chama cristella Lamarck. Recent from 

the Gulf of Siam to Java, the Moluccas, and Australia.

The apices are twisted to the left, and it is the right 

valve that is attached to the substratum. The generic 

value of the sinistral twist is not recognized by 

Davies.43

Pseudochama corticosa (Conrad) Gardner

Plate 13, figures 5, 16, 28

1833. Chama corticosa Conrad, Am. Jour. Sci., 1st ser., vol. 23,

p. 341. 

1838. Chama corticosa Conrad, Fossils of the medial Tertiary

of the United States, p. 32, pi. 17, fig. 3. 

1855. Chama corticosa Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 22, pi. 7, figs. 1-3. 

1858. Chama corticosa Emmons, North Carolina Geol. Survey

Kept., p. 288, fig. 210. 

1863. Chama corticosa Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 576. 

1903. Chama corticosa Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1400.

Shell sinistral, with strong concentric undulated laminae 

transversely striated; superior valve fiat; inner margin crenulated. Found with the preceding species [Chama congregata 

Conrad].—Conrad, 1833.

Type locality: James River near Smithfield, Isle of 

Wight County, Va.

Illustrations of specimens from the Duplin marl at 

Darlington, S. C., made by Tuomey and Holmes, have 

been reproduced.

Shell large, heavy, lamellose, attached by the strongly 

convex right valve; upper (left) valve flat, disklike; 

obscure, submedial carina most clearly defined on the 

umbones, becoming evanescent ventrally; posterior 

radial fold usually developed. Umbones very high and 

prominent, twisted toward the left; right umbo performing at least one complete revolution; umbo of left 

valve less strongly gyrate; outline of interior of valve, 

exclusive of cardinal area, subcircular. Surface of 

both valves covered with overlapping concentric lamellae that are attached dorsally, the ventral edges more 

flaring and more closely overlapping in the upper 

valve than in the lower; transverse striations irregular, 

most conspicuous on eroded surfaces and toward the 

ventral margin of the right valve. Ligament groove 

inset, crescentic, broader and deeper in the right valve 

than in the left. Dental socket in right valve broad, 

transversely elongated, central in position, separated 

from ligament groove by a shelly ridge and limited 

ventrally by a rude, horizontal, dental process; dentition in left valve little more than a roughened 

modification of the dorsal margin and, ventral to the

43 Davies, A. M., Tertiary faunas, vol. 1, p. 150, 1935.

tooth, an irregular pit for the reception of the corresponding process in the right valve. Muscle impressions much elongated, slightly reniform, the dorsal 

termination of the anterior adductor subumbonal; 

posterior adductor less produced dorsally. Pallial line 

simple. Inner surface finely and irregularly crenate a 

short distance from the margin of the valve.

Pseudochama corticosa (Conrad) is conspicuous 

among its congeners for its large size and sinistral beaks.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; near mouth of Baileys Creek, Prince George 

County; 3% miles north of Smithfield, Isle of Wight County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Murfreesboro, Hertford County; 6 miles west of Goldsboro, Wayne County; Rock Landing, Craven County. Duplin 

marl, Natural Well, 1% miles north of Magnolia, Duplin County; 

Lumber ton (near the bottling works), Robeson County.

Outside distribution: Miocene, Duplin marl, Darlington, Darlington County, S. C.

Superfamily CAKDIACEA

Family CARDJJIDAE 

Genus CARDIUM Linnaeus

1758. Cardium Linnaeus, Systema naturae, 10th ed., p. 678. 

1799. Cardium Lamarck, Prodrome d'une nouvelle classification 

des coquilles: Soc. d'histoire nat. Paris Mem., p. 86.

Type by subsequent designation (Schmidt, C. F., Versuch iiber 

die beste Einricht, etc., pp. 53, 176, Gotha, 1818) : Cardium 

costatum Linnaeus. Recent in the Indo-Pacific.

The type of the genus is a thin, gaping, highly inflated, transversely elongate shell, with narrow elevated 

radials persistent to the margin and interlocking at the 

margin with the radials of the opposite valve. The 

cardinals of the right valve are two prominent cusps 

united at the base and received between the anterior and 

posterior cardinals of the left valve, one beneath the 

other rather than side by side. Both the anterior and 

the posterior laterals are strongly developed in both 

valves.

Cardium s. s. is not recorded in the fossil state.

Genus CERASTODERMA Mbrch

1853. Cerastoderma Morch, Catalogus conchyliorum quae reliquit D. Alphonso d'Aguirra & Gadea Comes de Yoldi, 

fasc. 2, p. 34.

1930. Cerastoderma (Poll) Mo'rch. Stewart, Acad. Nat. Sci. 

Philadelphia Special Pub. 3, p. 259.

Type by subsequent designation (Von Martens, Zool. Rec. for 

1869, vol. 6, p. 586, 1870) : Cardium edule Linnaeus. Recent 

along European shores from the ' North Atlantic to the 

Mediterranean.

Valves closed; rotund, transversely or obliquely 

ovate, cordate in outline. Anterior and posterior areas 

inconspicuous or not defined. Kadial costae numerous, 

elevated, smooth, granulated, or imbricated. Intercostal areas simple. Left cardinals anterior when 

interlocked.
90 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Cerastoderma laqueatum (Conrad) Conrad

Plate 16, figure 4

1831. Cardium laqueatum Conrad, Acad. Nat. Sci. Philadelphia 

Jour., 1st ser., vol. 6, p. 258.

1938. Cardium laqueatum Conrad, Fossils of the medial Tertiary of the United States, p. 31, pi. 17, fig. 1.

1839?. Car Mum ingens Wagner. Unpublished figure.

1863. Cardium (Cerastoderma) laqueatum Conrad, Acad. Nat. 

Sci. Philadelphia Proc. for 1862, p. 576.

1897. Cardium ingens Wagner. Dall, Wagner Free Inst. Sci. 

Trans., vol. 5, p. 10, pi. 3, fig. 2.

1900. Cardium (Cerastoderma) laqueatum Conrad. Dall, idem, 

vol. 3, pt. 5, p. 1092.

1904. Cardium (Cerastoderma) laqueatum Conrad. Glenn, 

Maryland Geol. Survey, Miocene, p. 319, pi. 86, fig. 1.

Shell cordate, ventricose, thin, with about 33 subtriangular, 

transversely wrinkled ribs; umbones prominent; lunule not 

profoundly impressed and somewhat lanceolate; cardinal tooth 

subulate.

Cab[inet of the] Academy.

Inhabits—Fossil from Maryland.

Length 1% inches; length and height nearly equal. The only 

determinate fossil species of its genus yet discovered in this 

country; I found it only in the clay beds at St. Marys River, 

and always in a state of decomposition, that rendered it impossible to obtain any but mutilated specimens.—Conrad, 1831.

A left valve from the Choptank formation at Jones 

Wharf on the Patuxent River, St. Marys County, Md., 

was figured by Glenn, and the illustration is reproduced in this paper. The specimen is in the collection 

of the Maryland Geological Survey, Johns Hopkins 

University, Baltimore, Md.

Shell large; the height and width nearly equal; 

rounded and produced anteriorly, obliquely truncated 

posteriorly, slightly arcuate ventrally. Umbones inflated. Radial ribs generally rounded, less frequently 

flat-topped or triangular, slightly wider than the interradials, normally 28 to 32 in number, exclusive of the 

6 to 9 low, overturned ridges on the posterior area; very 

faint secondary radial striae sometimes visible on the 

summits of the primaries; concentric sculpture of undulatory incrementals that are strongest near the posterior margin of the valves; ribs made up of hollow 

cones, one within the other, -laid obliquely on the shell, 

the apices directed toward the umbones—a very weak 

structure responsible for the decorticated condition in 

which the valves of this species are usually found; 

sculpture best preserved near the ventral margins; scars 

left by the ribs in the form of pairs of elevated radiating lines, each pair marking the lateral boundaries of 

a former rib.

Cerastoderma laqueatum (Conrad) is a relatively 

lower, broader form than C. acutilaqueatum of the 

same author. The ribs are slightly fewer and are 

usually flat or rounded on the top rather than triangular, as in the latter species. Dinocardium robustum (Solander) is not quite so broad as C. laqueatum, a 

little more oblique, with a more strongly differentiated

posterior area and with fewer but broader radials. It 

occupies in the fauna of the Duplin and Waccamaw 

much the same position that C. laqueatum (Conrad) 

does in the St. Marys.

C. laqueatum (Conrad) is represented in the Area 

zone of the Choctawhatchee formation by Cardium 

(Cerastoderma} laqueatum blountense Mansfield, 1932. 

The Floridian species is not so large as that from the 

middle Atlantic slope, is less oblique, and differs in 

the details of the sculpture pattern. In these variations it approaches Cerastoderma waltoniamwi, abundant in the Shoal River formation of the Alum Bluff 

group.

Distribution: Virginia: Miocene, St. Marys formation?, 

Nomini Cliffs, Westmorland County. St. Marys formation, 

half a mile below Bowlers Wharf, Essex County; Claremont 

Wharf (lower bed), and old Claremont Wharf (lower bed), 

Surry County.

Outside distribution: Miocene, Hawthorn formation, Porters 

Landing, Effinghani County, Ga. Choptank formation, Greensboro, Caroline County, Md.; Dover Bridge and Sand Hill, Talbot 

County, Md.; Governor Kun, Flag Pond, and St. Leonards Creek, 

Calvert County, Md.; Jones Wharf, Turner, Pawpaw Point, and 

Cuckold Creek, St. Marys County, Md. St. Marys formation, 

Cove Point, Calvert County, Md.; Langleys Bluff and St. Marys 

River, St. Marys County, Md.

Cerastoderma acutilaqueatum (Conrad) Conrad

Plate 16, figure 5

1839. Cardium acutilaqueatum Conrad, Fossils of the medial 

Tertiary of the United States, back cover of No. 1.

1840. Cardium acutilaqueatum Conrad, idem, p. 34, pi. 18, fig. 2. 

1863. Cardium (Cerastoderma) acutilaqueatum Conrad, Acad.

Nat. Sci. Philadelphia Proc. for 1862, p. 576. 

1900. Cardium (Cerastoderma) acutilaqueatum Conrad. Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, p. 1092.

Shell oblique, ovate, ventricose, rounded at base and posterior 

extremity; ribs about 36, subtriangular, narrow, prominent; 

posterior margin very long, oblique, and subrectilinear; umbo 

narrow, summit very prominent; margin profoundly crenate. 

Length 4 inches, height 4y2 inches. Locality, Yorktown, Va.— 

Conrad, 1839.

This species has been confounded with C. laqueatum, the ribs 

of which, in immature specimens, resemble those of the present 

species in their subtriangular form; but the latter shell is 

proportionately more elevated, being higher than long, whilst 

the former is rather more in length than height.—Conrad, 1840.

Conrad's illustration of his holotype, a right valve, 

has been reproduced.

Cerastoderma acutilaqueatum weathers in much the 

same manner that Cerastoderma laqueatum does. It 

is more widely distributed than the latter species, though 

the geologic and geographic ranges of both are much 

the same. The former tends, in a general way, to be 

the more common and to occur at a slightly higher horizon and in a more southern area. Dall reports the 

species from the upper bed at Alum Bluff, Liberty 

County, Fla., an outcrop considered by Mansfield to be 

typical of the Ecphora zone of the Choctawhatchee formation.
PART 1. PELECYPODA 91

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; a quarter of a mile south of the Smithfield powerhouse, Isle of Wight County; a quarter to % mile 

below Sycamore, Southampton County; % mile north of Chuckatuck, 2% miles northwest of Suffolk, 1 mile west of Suffolk, 

iy2 miles northeast of Suffolk, 1 mile northeast of Suffolk, 

and % mile below the Suffolk'waterworks dam, Nansemond 

County.

North Carolina: Miocene, Yorktown formation, 2 miles below 

•Toddy Station, 2 miles southeast 'of Tugwell (on Jacobs 

Branch), 3 miles south of Farmville, 2% miles north of Standard, 8 to 9 miles west of Greenville (on the east side of Pinelog Branch), 9 to 10 miles south of Greenville, and 1 mile northwest of Galloway Crossroads, Pitt County; 1% miles northeast of Chocowinity, Beaufort County, % mile east of Lizzie, 

Greene County; Rock Landing, Craven County. Duplin marl, 

Natural Well, Duplin County.

Outside distribution: Miocene, Choctawhatchee formation, 

Alum Bluff (upper bed) (Dall), Calhoun County, Fla.

Cerastoderma virginianum (Conrad) Conrad 

Plate 16, figure 3

1839 (April). Cardium virginianum Conrad, Fossils of the medial 

Tertiary of the United States, back cover of No. 1.

1839 (December). Cardium quadrans Rogers and Rogers, Am. 

Philos. Soc. Trans., 2d ser., vol. 5, p. 375, pi. 30, fig. 1.

1840, Cardium virginianum Conrad, Fossils of the medial Tertiary of the United States, p. 33, pi. 18, fig. 1.

1840. Cardium ingens Wagner. Conrad, idem, p. 33. Not C. 

Ingens Wagner, 1839?

1863. Cardium (Cerastoderma) virginianum Conrad, Acad. Nat.

Sci. Philadelphia Proc. for 1862, p. 576.

,1900. Cardium (Cerastoderma) virginianum Conrad. Dall, 

Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, p. 1094.

1932. Cardium (Cerastoderma) virginianum Conrad. Mansfield, Florida Geol. Survey Bull. 8, p. Ill, pi. 17, fig. 6.

Shell very oblique, convex-depressed; ribs about 26, broad, 

flat; interstices narrow and very shallow; summit narrow and 

not very prominent, oblique; anterior margin rectilinear, extremity angular; posterior extremity rounded; basal margin 

very long, arcuated. Length about 4 inches. Locality, James 

River, near Smithfield.—Conrad, 1839.

Conrad's illustration of his holotype, a right valve, 

has been reproduced.

Cerastoderma virginianum (<3onrad) is an unusually 

well characterized species. The diagnostic features are 

the rhomboidal outline; the low, flattened, posterior 

umbones; the rectilinear anterior margin; the sharply 

differentiated posterior area; and the very low, broad, 

flat-topped ribs, often showing faint, secondary striation. The posterior area is unsculptured except for 

five to seven impressed lines, which become obsolete 

before reaching the margin. The concentric sculpture 

is similar to that of the other members of the subgenus. 

Even the merest fragment may be determined if it 

includes a bit of the hinge line or of the radial 

sculpture.

The species is limited in its known distribution to 

the Yorktown of southern Virginia and northern North 

Carolina, and to the Ecphora zone of the Choctawhatchee formation of Florida (Mansfield, 1932).

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, Bellefield, York County; l1/^ miles west of the mouth of 

Baileys Creek, Prince George County; * Smithfield and Zuni, 

Isle of Wight County; Sycamore, 3 to 4 miles above the lower 

Seaboard Railway bridge, and % to % mile above the lower 

Seaboard Railway bridge over the Meherrin River, Southampton 

County.

North Carolina: Miocene, Yorktown formation, 1% miles 

above Branches Bridge, 1 mile above Branches Bridge, and 

Branches Bridge, Northampton County; Halifax (on Mr. Durham's farm), % mile above the Atlantic Coast Line Railway 

bridge and at Palmyra Bluff, Halifax County.

Outside distribution: Miocene, Choctawhatchee formation, 

Alum Bluff (upper bed), Calhoun County, Fla. (?) Miocene, 

Gay Head, Mass. (Dall).

Genus TRACHYCARDIUM Morch

1853. Trachycardium Morch, Catalogus conchyliorum quae reliquit D. Alphonso d'Aguirra et Gadea Comes de Yoldi, 

fasc. 2, p. 34.

Type by subsequent designation (Von Martens, Zool. Rec. for 

1869, vol. 6, p. 586, 1870) : Cardium isocardia Linnaeus. Recent on the east coast from Hatteras to Trinidad; fossil in the 

later Tertiary and Pleistocene.

Valves closed, rotund, or ovate-cordate in outline; 

ribs concentrically sculptured or granulose, many of 

them elaborately imbricated or tuberculate; left cardinals anterior when interlocked.

Trachycardium isocardia (Linnaeus)

Plate 15, figures 19, 20

1758. Cardium isocardia Linnaeus, Systema naturae, 10th ed., 

p. 679.

1782. Cardium isocardia Linnaeus. Chemnitz, Conchylien cabinet, vol. 6, p. 182, pi. 17, figs. 174-176.

1845. Cardium isocardia Linnaeus. Reeve, Conchologia iconica, 

vol. 2, Cardimm, pi. 17, fig. 84.

1856. Cardium egmontianum Shuttleworth, Jour, conchyliologie, 

vol. 5, 2d ser., vol. 1, p. 172.

1858. Cardium isocardia Linnaeus. Holmes, Post-Pleiocene 

fossils of South Carolina, p. 25, pi. 5, fig. 4.

1875. fCardium eburniferum Guppy, Annals and Mag. Nat. History, ser. 4, vol. 15, p. 51, pi. 7, fig. 3.

1900. Cardium (Trachycardium) isqcardia Conrad. Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt 5, p. 1085.

Cardium testa cordata ; sulcis squamis fornicatis imbricatis.— 

Linnaeus, 1758.

Paired valves of a .Recent individual from the Florida coast (U. S. Nat. Mus. 57147) have been figured. 

The shell measures 47.5 millimeters in height and 37.5 

millimeters in width.

This, is the type of the subgenus and has about 27 to 33 

ribs, with comparatively low and distant arcuate imbricating 

scales; the ribs are squarish and the interspaces channeled, 

the scales tend to be seated on the posterior side of the ribs; 

on the anterior face of the shell the imbrications are closer, 

lower, and heavier, but these ornaments change their form very 

gradually from one end of the shell to the other.

Linn6 and the earlier writers confounded this shell with a 

similar form from the East Indies, which was afterwards 

named C. squamosum by Gmelin. A specimen of the West 

Indian shell was in the Linnaean cabinet and serves to hol<J
92 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

the name, though among the figures cited by him several 

referred to the Oriental shell.-—Dall, 1900.

Shell somewhat inequilateral, obliquely cordate; umbones high, inflated; posterior margin sharply serrated.

Trachycardium isocardia (Linnaeus) is relatively 

lower than its precursor, T. emmonsii (Conrad), the 

umbones are less prominent, and the medial and lateral 

sculptures are less elaborate and less sharply differentiated. In the latter, furthermore, the medial ribs are 

decked with high, vaulted imbrications, which on the 

posterior side of the shell are abruptly flattened and 

continuous with one another. In the former, the imbrications are lower, more distant, and frequently 

confined to the posterior half of the rib.

Distribution: North Carolina: Pliocene, Waccamaw formation, Wilmington, New Hanover County (U. S. Nat. Mus. 

145291).

Outside distribution: Pliocene, Caloosahatchee River and 

Myakka River, Fla. Pleistocene, Abbapoola, Folly Island, and 

Simmons Bluff, S. C.; Orient, Hillsborough County, Fla.; Manatee Station and North Creek near Osprey, Manatee County, 

Fla.; Eau Gallic, Brevard County, Fla.; 1 mile south of Daytona 

Beach, Volusia County, Fla.; Labelle, Hendry County, Fla.; Fort 

Lauderdale, Broward County, Fla.; Big Pine Key and Torch Key, 

Fla. Recent, Hatteras to Trinidad and east to Bermuda in 

less than 50 fathoms.

Trachycardium emmonsii (Conrad) Conrad

1858. Cardium muricatum Emmons, North Carolina Geol. Survey Rept, p. 301, figs. 232, 233. Not C. muricatum 

Linnaeus, 1758, nor Tuomey and Holmes, 1856.

1863. Cardium (Trachycardium) muricatum'i Linnaeus. Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 576.

1867. Cardium (Trachycardium) emmonsii Conrad, Am. Jour. 

Conchology, vol. 3, p. 13.

1887. Cardium fioridanum Heilprin, Wagner Free Inst. Sci. 

Trans., vol. 1, pp. 92, 103, pi. 11, fig. 25.

1900. Cardium (Trachycardium) emmonsi Conrad. Dall, idem, 

vol. 3, pt. 5, p. 1084.

The specimen given 'in the figure resembles the muricatum, 

but it is more elongated, and its crenulations appear to differ. 

I have obtained only one specimen; and hence cannot speak of 

the permanence' of-its characters. It occurs in Walkers Bluff, 

on the Cape Fear.—Emmons, 1858.

This shell is shorter or comparatively more elevated than 

C. muricatum, with a thicker cardinal plate. In the figure 

the ribs are also flatter on the back and furnished with broad 

scales, not small tubercles as in C. muricatum.—Conrad, 1867.

This form has 9 ribs on the posterior with hoodlike imbrications ; 10 on the disk with high, arching imbrications continuous 

on the posterior side; and 10 anterior, with cuplike ornaments 

like strung convolvulus flowers. The nearest recent relative 

is C. consors Broderip of the Pacific coast.—Dall, 1900.

The species is considerably higher than wide, representative individuals measuring 60.6 millimeters, 74.3 

millimeters, and 77.0 millimeters in height, and 47.0 

millimeters, 57.5 millimeters, and 57.8 millimeters in 

width, respectively. The valves are somewhat rounded 

anteriorly, truncate and serrate posteriorly. The umbones are high and narrow. The sculpture is more 

elaborate than in any other member of the genus within

the area. The ribs vary slightly in number and in 

the degree of differentiation between the medial and 

lateral areas.

Conrad's species is referred to Trachycardmm s.s'. 

The resemblance between T. emmonsii and T. isocardia 

seems much closer than that between T. emmonsii and 

T. muricatum. The relationship is indicated both in 

the outline and contour of the shell and in the sculpture pattern. Dallocardia Stewart should probably 

include, however, T. oedolium Dall from the Caloosahatchee of Florida ( and T. ~b&uydenense Dall from 

Jamaica. T. ustrise Gardner, with 35 ribs, abundant in 

the Shoal Eiver formation, is an earlier member of the 

T. isocardia group.

This daintily sculptured cockle is fairly common at 

a single horizon and is represented by a dozen or so 

perfectly preserved valves. It has not been recognized 

in strata older than the Pliocene.

Distribution: North Carolina: Pliocene, Waccamaw formation. Walkers Bluff, Bladen County (Emmons) ; Neills Eddy 

Landing, Columbus County, N. C.

Outside distribution: Pliocene, Caloosahatchee marl, Caloosahatchee River and Shell Creek, Fla.

Section DALXOCARDIA Stewart

1930. Dallocardia Stewart, Acad. Nat. Sci. Philadelphia, Special 

Pub. 3, p. 264.

Type by original designation: Cardium quadrigenerium Conrad. Recent off the California coast near Santa Barbara.

The differences that separate Dattocardia from 

Trachycardium s.s. seem of doubtful subgeneric value. 

The hinge of Dallocardia is similar to that of Trachycardium but not so heavy, and the ornamentation on 

the crests of the medial ribs are, in Dallocardia, more 

commonly confined to the posterior portion of the rib. 

T. muricatum is considered by Stewart to exemplify 

the characteristic features of his subgenus.

Trachycardium muricatum (Linnaeus) Dall

Plate 15, figure 21

1758. Cardium muricatum Linnaeus, Systema naturae, 10th

ed., p. 680. 

1900. Cardium (Trachycardium) muricatum Linnaeus. Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, p. 1089.

C. testa subcordata sulcata lateribus muricata. Habitat ad 

sinum Campechiensem.—Linnaeus, 1758.

Dall has given an extensive discussion of the variations in the sculpture pattern of muricatum. Although it is rarely recorded in the Tertiary faunas, the 

precursal forms are sufficiently close to have been confused with the Recent species in the early check lists 

and synonymies. The closely related oedalium Dall 

described from the Caloosahatchee Pliocene of southern 

Florida, is represented in the Choctawhatchee Miocene 

of northern Florida by oedalium Tiarveyense Mansfield, 1932. The subspecies is confined to the Cancellaria zone, which is the uppermost zone of the Choc-
PART 1. PELECYPODA 93

tawhatchee formation, at the top of the Miocene section 

of Florida. Mansfield 44 referred in his description to 

"2 small and eroded valves having 31 or 32 ribs and a 

fragment of a larger specimen," which may be referable to his harveyense. They were collected in the 

Duplin marl, 1 mile east of Darlington, S. C. 

A shell from the Cape Fear Kiver is figured.

Genus TRIGONIOCARDIA Ball

1900. Trigoniocardia Dall, Wagner Free Inst. Sci. Trans., 

vol. 3, pt. 5, p. 1075.

1930. Trigoniocardia^ Dall. Stewart, Acad. Nat. Sci. Philadelphia, Special Pub. 3, p. 267.

Type by original designation: Cardium graniferum Broderip 

and Sowerby. Recent from the Gulf of California to Panama.

Shell small, few-ribbed, medial ribs very strong; posterior 

end subtruncate with smaller, closer ribs; channels strongly 

concentrically sculptured; shell colorless, periostracum 

smooth.—Dall, 1900.

The genus Fragum is not known from American waters and 

apparently never reached the New World. Trigoniocardia Dall 

(1900, p. 1075), which was described as a section of the subgenus Fragum, has a different hinge and is to be treated as a 

distinct genus. These two genera were considered related 

because of the prominent posterior umbonal slope present on 

both, but Fragum has the posterior laterals crowded toward 

the cardinals, while Trigoniocardia has the anterior laterals 

crowded against the cardinals. * * * The hinge of Trigoniocardia seems more closely related to that of Trachycardium 

than to that of Fragum. The hinge plate is wider than on 

Fragum so that the cardinals do not protrude ventrally where 

they join the hinge, while the anterior right and posterior left 

cardinals are less developed than in Fragum. This wide hinge 

plate and unequal cardinals are characteristic of Trachycardium s. s. and suggest that Trigoniocardia is related to it.— 

Stewart, 1930.

Trigoniocardia has not been recognized in strata older 

than the Miocene.

Subgenus AMERICARDIA Stewart

1930. Americardia Stewart, Acad. Nat. Sci. Philadelphia, Special 

Pub. 3, p. 267.

Type by original designation: Cardium medium Linnaeus, 

Systema naturae, 10th ed., p. 678, 1758. Recent from Cape 

Lookout, N. C., to Santa Marta, Brazil; abundant in the West 

Indies. Miocene and Pliocene of the middle Atlantic and the 

Gulf Coastal Plain.

The subgenus is characterized by the position of the 

cardinals, which are symmetrically disposed between 

the anterior and posterior laterals, and by the absence 

of costal ornamentation other than an exaggerated incremental sculpture. Americardia, as defined by Stewart, includes the Tertiary species formerly referred to 

Trigoniocardia. In the symmetry of the dentition, 

Americardia suggests the oriental group of Ctenocardia' 

H. and A. Adams.

** Mansfield, W. C., Florida Geol. Survey Bull. 8, p. Ill, 1932.

Trigoniocardia (Americardia) media (Linnaeus) Stewart

1758. Cardium medium Linnaeus, Systema naturae, 10th ed., p.

678. 

1844. Cardium medium Linnaeus. Reeve, Conchologia iconica,

vol. 2, Cardium, pi. 6, fig. 30. 

1861. Cardium venustum Dunker, Malakozool. Blatter, vol. 8,

p. 37. 

1887. Hemicardium colutnba Heilprin, Wagner Free Inst. Sci.

Trans., vol. 1, p. 93, pi. 11, figs. 26, 26a. 

1900. Cardium (Fragum) medium Linne". Dall, idem, vol. 3, pt.

5, p. 1101. 

1904. Cardium (Fragum) medium LinnS. Glenn, Maryland

Geol. Survey, Miocene, p. 322, pi. 86, figs. 6a, 6b.

C. testa subcordata subangulata; valvulis angulatis sulcatis 

laevibus. Habitat in O. Indico.—Linnaeus, 1758.

This species is abundant in the West Indies and differs 

especially in the amount of impression of the posterior area 

and the elevation of the upper part of the posterior margin 

projecting from the central part of the depression when the 

valves are closed. Some specimens have only a slight depression, others have it very marked, and the intermediate stages 

are so common that it is evident they are of little systematic 

value.—Dall, 1900.

Shell high, the outline of the interior squarish. Posterior margin truncated and rather sinuous. Anterior 

margin slightly rounded. Ventral margin nearly 

straight. Umbones high, narrow, angular, involute. 

A well-marked angulation extending from the umbo 

to the posterior basal margin; posterior area feebly 

undulated and depressed. Eadial ribs, 33 to 37, covered 

with crowded concentric imbrications, which are most 

prominent on the posterior portion of the shell. These 

are readily removed by erosion and reveal the polished 

rectangular ribs without a trace of the original 

sculpture.

Distribution: North Carolina: Miocene, Duplin marl, Natural 

Well and iy2 miles north of Magnolia, Duplin County. Pliocene, 

Waccamaw formation, Neills Eddy Landing, Columbus County.

Outside distribution: Miocene, St. Marys formation, St. 

Marys River, Md.? Pliocene, Caloosahatehee marl, Caloosahatchee River, Shell Creek, and Alligator Creek, Fla. Recent, 

Cape Lookout, N. C., to Santa Marta, Brazil, in less than 50 

fathoms except off the West Indies, where it occurs in both 

shallow and deep water.

Genus LAEVICARDIUM Swainson 

1840. Laevicardium Swainson, Treatise on malacology, p. 373.

Type by subsequent designation (Bucquoy, Dautzenberg, and 

Dollfus, Mollusques marins du Rousillon, vol. 2, p. 298, 1892) : 

Cardium europaeum Wood — Cardium norvegicum Spengler. 

Recent on the west coast of Europe and in the Mediterranean.

The genus is best known by the absence of strong 

radial sculpture. The hinge line is arcuate and the 

dentition more delicate than in many of the Cardia. 

The anterior cardinal of the right valve is rudimentary, 

but the posterior cardinal is a prominent conical peg 

received between the two left cardinals. The left pos401033—43-
MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

terior lateral is very feeble. The obscure radial sculpture is most strongly indicated in the crenation of the 

inner margins.

Laevicardium sublineatum (Conrad) Conrad

Plate 15, figures 11, 12, 15, 16

1841. Cardium sublineatum Conrad, Am. Jour. Sci., 1st ser., p.

347, pi. 2, fig. 13. 

1843. Cardium suNineatum Conrad, Assoc. Am. Geologists and

Naturalists Proc. and Trans., p. 110, pi. 5, fig. 13. 

1845. Cardium sublineatum Conrad, Fossils of the medial Tertiary of the United States, p. 66, pi. 37, fig. 4. 

1856. Cardium sublineatum Conrad. Tuomey and Holmes,

Pleiocene fossils of South Carolina, p. 64, pi. 19, fig. 3. 

1863. Cardium (Laevicardium) sublineatum Conrad, Acad. Nat.

Sci. Philadelphia Proc. for 1862, p. 576. 

1900. Cardium (Laevicardium) sublineatum, Conrad. Dall,

Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, p. 1111. 

1906. Laevicardium sublineatum, Conrad. Bb'se, Inst. Geol.

Mexico Bol. 22, pp. 25, 28, 79, pi. 2, figs. 1-3; pi. 11,

fig. 4.

Obliquely obovate, thin, slightly ventricose, with obsolete 

radiating lines, most distinct near the ends; submargins of 

anterior and posterior sides destitute of radiating lines; within 

striated; margin crenulated.—Conrad, 1841.

Type locality: Wilmington, 1ST. C. Waccamaw 

formation.

Dimensions of figured specimens: Eight valve, height 

28.7 millimeters, width 29.0 millimeters, convexity 8.7 

millimeters. Left valve, height 26.0 millimeters, width 

28.5 millimeters, convexity 8.0 millimeters.

Figured specimens, a right and a left valve of different individuals (U. S. Nat. Mus. 325559) from the 

Waccamaw formation at Neills Eddy Landing on the 

Cape Fear River, Columbus County, N. C.

The outer smooth and polished surface is readily removed by erosion and reveals the radially striate, 

porcellanous layer beneath.

Distribution: Virginia: Miocene, Yorktown formation, % 

mile north of Chuckatuck and 1^ miles northeast of Suffolk, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, 14 to % 

mile above Edenhouse Point, Bertie County. Duplin marl, 

Natural Well and at several neighboring localities, Duplin 

County. Pliocene, Waccamaw formation, Walkers Bluff, 

Bladen County; Lake Waccamaw, Cronly (^ mile east of the 

factories), and Neills Eddy Landing, Columbus County; Wilmington, New Hanover County.

Outside distribution: Miocene, Duplin marl, Darlington, 

Darlington County, S. C.; Santa Rosa and Santa Maria Tetetla, 

V,era Cruz, Mexico. Waccamaw formation, Nixons, Tillys Lake, 

and Todds Ferry, Horry County, S. C.

Superfamily TELLINACEA

Family TELLINIDAE 

Genus TELLINA (Linnaeus) Lamarck

1758. Linnaeus, Systema naturae, 10th ed., p. 674. 

1799. Lamarck, Prodrome d'une nouvelle classification des coquilles, Soc. histoire nat. Paris Me"m., p. 84.

Type by subsequent designation (Schmidt, C. F., Versuch 

iiber die beste Einricht, etc., pp. 51, 177, Gotha, 1818) : Tellina 

radiata Linnaeus. Recent in the West Indies.

Shell transversely ovate to ovate-trigonal in outline, 

compressed; usually rostrate and flexed to the right 

posteriorly, and broadly depressed in front of the 

rostrum. Umbones low, subcentral or posterior, often 

opisthogyrate. External surface rarely smooth; dominant sculpture concentric, regular, and generally incremental in character; radial ornamentation commonly 

suggested by the color pattern and by the reinforcing 

internal rays, rarely by the sculpture; oblique sculpture 

developed in one group. Ligament external, opisthodetic. Two cardinals, one of them bifid, developed in 

each valve, interlocking in the closed valves so that 

the bifid teeth are flanked on either side by a simple 

laminar tooth. Anterior and posterior laterals developed in some groups in both valves; in others, 

reduced to a single right anterior lateral. Sinus free 

or coalescent ventrally with the pallial line, often discrepant in the two valves, the dorsal margin of the 

sinus commonly uniting the anterior and posterior 

adductors.

The Tellinas are essentially a modern group, though 

they have their roots in the Mesozoic.

Subgenus MOERELLA Fischer

1887. Hoerella Fischer, Manuel de conchyliologie et de paleontologie conchyliologique, p. 1147.

Type by monotypy: Tellina, donacina, Linnaeus. Recent off 

the European coasts from the Hebrides to the Mediterranean. 

Fossil in the Coralline Crag of England.

Shell rather small for the genus, transversely ovate, 

obscurely rostrate posteriorly. Sculpture dominantly 

concentric, the Kecent species often rayed with colors. 

Umbones low, opisthogyrate. Lunule and escutcheon 

extremely narrow, indicated but not well defined. 

Ligament external, opisthodetic. Two cardinal teeth 

in each valve, the anterior right and the posterior left 

simple and laminar, the posterior right and the anterior 

left stouter and bifid. True laterals not developed in 

the left valve, though the edges are beveled to function as laterals and are received within the lateral 

sockets on the right valve; the anterior lateral more 

elevated and closer to the umbo than the posterior. Pallial sinus confluent ventrally with the pallial line 

throughout the greater part of its extent.

Most of the east coast Tertiary Tellinas, referred in 

earlier publications to Angulus, seem more closely 

allied to Moerella. Angulus is an Indo-Pacific group 

in which only a single lateral—the right anterior—is 

developed; it has not been recognized in the Miocene 

and lower Pliocene faunas of the east coast.

Tellina (Moerella) declivis Conrad

1834. Tellina declivis Conrad, Acad. Nat. Sci. Philadelphia Jour., 

1st ser., vol. 7, p. 131.
PART 1. PELECYPODA 95

1840. Tellina declivis Conrad, Fossils of the medial Tertiary of

the United States, p. 35, pi. 19, fig. 1. 

1863. Tellina (Angulus) declivis Say. Conrad, Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 573. 

1894. Tellina, (Angulus) declivis Say. Whitfield, U. S. Geol.

Survey Mon. 24, p. 77, pi. 14, figs. 4-6. 

1900. Tellina (Angulus) declivis Conrad. Dall, Wagner Free

Inst Sci. Trans., vol. 3, pt. 5, p. 1029. 

1904. Tellina (Angulus) declivis Conrad. Glenn, Maryland

Geol. Survey, Miocene, p. 298, pi. 72, fig. 14. 

1909. Tellina declivis Conrad. Grabau and Shinier, North

American index fossils, vol. 1, p. 567, fig. 777a.

Shell somewhat elliptical, with the anterior [posterior] side 

short, and the margin obliquely truncated; posterior [anterior] 

end regularly rounded; beaks hardly prominent; lateral teeth 

distinct.

Locality: Yorktown, Va.

It resembles in outline the Amphidesma subreflexa noMs; and 

might, viewing the exterior only, be mistaken for that shell.— 

Conrad, 1834.

Shell thin, fragile, compressed, inequilateral. Outline ovate-elongate. Umbones low, inconspicuous, 

opisthogyrate, situated about two-thirds of the distance 

toward the posterior margin. Anterior dorsal margin 

produced, gently sloping into the rounded anterior end ; 

posterior slightly contracted at the nymph, the contraction most noticeable in the right valve; obscurely truncate from the umbones to the base; ventral margin 

straight, ^usually at-a lo.w angle to the anterior dorsal 

margin. Surface feebly sculptured with concentric 

groovings that are least faint anteriorly and near 

the base, though obsolete on the umbones. Cardinals normal in both valves, but rather small and rude. 

Anterior lateral of right valve strong, not in line with 

the anterior cardinal, but a little dorsal to it; posterior 

lateral short, low, and inconspicuous, located near the 

ventral terminal of the nymph; margin o.f valve slightly 

contracted at this point, thus making a little V-shaped 

groove for the reception of the feeble prominence on the 

dorsal margin of the left valve. No true laterals developed in left valve but dorsal margins modified to 

function as laterals. Slightly thickened anterior ray 

often visible internally. Muscle scars and pallial line 

and sinus usually obliterated. Anterior scar somewhat elongated and very irregular; posterior semielliptic. Sinus, a wavy line rising a little higher in 

the right valve than in the left and reaching its maximum at a point on a vertical with the umbones, then 

more gradually descending and falling only a little 

short of the anterior scar.

Tellina declivis Conrad is one of the most abundant 

representatives of the genus in the Tertiary of North 

Carolina and, more particularly, of Virginia along the 

York River and in the vicinity of Suffolk, Nansemond 

County. Though inconstant in outline, the species has 

an individuality that makes it readily recognizable—a 

generally untidy appearance owing to the irregularity 

of outline and to the nicked and ragged margins of the 

thin and fragile valves. It is less elongated anteriorly

than T. producta Conrad, and the anterior dorsal margin is generally at a low angle to the base instead of 

parallel with it, as in the latter. It is more elongated, 

however, than T. calpix, from the Yorktown of North 

Carolina, an oval form with subcentral umbones and 

rounded dorsal margins nearly similar to one another. 

T. macilenta Dall, of the Duplin fauna, is relatively 

higher, with a much higher umbonal angle. T. sayi 

Deshayes, of the Pliocene and Eecent, is closely allied 

and is its possible descendant. T. sayi, however, averages a little smaller, is the more regular in outline, and 

is obliquely produced and truncated along its posterior 

margin. In T. declivis, there is a small contraction at 

the nymph; below it, the slightly flaring margin may 

be very gently arched or rather obscurely truncated. 

The angle of the margin with the base is decidedly 

higher than in T. sayi and often approaches a right 

angle. The dentition of T. sayi is usually a little 

stronger, and the dorsal margin of the pallial sinus 

seems a trifle higher. The two forms rarely occur 

together, T. declivis being essentially a Miocene species 

north of the Hatteras, whereas T. sayi is a post-Miocene 

shell south of the Hatteras. The former, however, persists in much reduced numbers in the Caloosahatchee 

fauna.

Distribution: Virginia: Miocene, St. Marys formation, 1 to 2 

miles below Bowlers Wharf, Essex County; Union Mills, 2% 

miles south of Farnham, Richmond County; Urba*ina, Middlesex County; Sunken Marsh Creek (lower bed), James River, 

Surry County. Yorktown formation, Yorktown, York County; 

Petersburg, Dinwiddie County; 2 miles northwest of Smithfield; 

&y2 miles below Zuni, Isle of Wight County; % mile north of 

Chuckatuck, % mile east of Everets Post Office, 5% miles 

northwest of Suffolk, 2y2 miles northwest of Suffolk, 1% miles 

north of Suffolk, l 1^ miles north of Suffolk, iy2 miles northeast 

of Suffolk, 1 mile northeast of Suffolk, half a mile below the' 

Suffolk waterworks dam, and 1 mile south of Deep Creek, 

Nansemond County.

North Carolina : Miocene, Yorktown formation, Palmyra Bluff, 

Halifax County; half a mile above Bells Bridge, Tar River, 

Edgeconibe County; Tar Ferry on Wiccacon Creek (opposite 

Harrellsville), 1% miles below Tar Ferry, and Mount Pleasant 

Landing, Hertford County; % to % mile above Edenhouse 

Point, Bertie County.

Outside distribution: Miocene, Calvert formation, Shiloh, 

Cumberland County, N. J.; Plum Point, Calvert County, Md. 

Choptank formation, Jones Wharf, St. Marys County, Md. 

Pliocene, Caloosahatchee marl, Shell Creek, Fla.

Tellina (Moerella) sayi (Deshayes ms.) Dall

Plate 17, figure 4

1822. Tellina polita Say, Acad. Nat. Sci. Philadelphia, 1st ser., 

vol. 2, p. 276. Not T. polita Poli, 1795, T. polita 

Spengler, 1798, T. polita Pulteny, 1813, or T. polita 

Sowerby, 1825.

1834. Tellina polita Say, Am. conchology, pt. 7, pi. 65, fig. 2.

1846. Tellina, polita Say. Hanley, Thesaurus conchyliorum, 

vol. 1, pt. 6, p. 282, pi. 57, fig. 60.

1856. Tellina polita Say. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 91, pi. 22, fig. 6.
96 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OP VIRGINIA AND NORTH CAROLINA

1856. Tellina (Angulus) polita Say. H. and A. Adams, Genera

Recent Mollusca, vol. 2, p. 398. 

1858. Angulus polita Say. Holmes, Post-Pleiocene fossils of

South Carolina, p. 45, pi. 8, fig. 2. 

1900. Tellina sayi Deshayes, ms., fide Dall. 

1900. Tellina (Angulus) sayi Deshayes. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 5, p. 1034.

Shell transversely subtriangular, minutely wrinkled concentrically, white, immaculate; anterior [posterior] margin rather 

shorter than the posterior [anterior] one, the hinge slope 

declining, in a very slightly arquated line to a subacute termination; basal margin nearly rectilinear from behind the 

middle to the anterior [posterior] termination; a lateral tooth 

behind [in front of] the primary teeth.

Length two-fifths of an inch, breadth thirteen-twentieths of 

an inch.

Inhabits the southern coast.

Cabinet of the Academy and Philadelphia Museum.

Not unfrequent on the beach of South Carolina and east 

Florida.—Say, 1822.

The well-known name of this species must be changed, as 

it had been used for a Tellina 3 or 4 times before Say so applied it, and one of the prior attempts at least was made on 

a species of Angulus. The name of Deshayes is suggested in 

one of his manuscripts in my possession.—Dall, 1900.

A Recent left valve (U. S. Nat. Mus. 128444) from 

off the coast of South Carolina has been figured. It 

measures 10.0 millimeters in height and 17.4 millimeters 

in width.

Shell rather thin but solid, moderately compressed, 

often slightly flexuous in front of the posterior fold. 

Posterior end cuneate, the anterior rounded, the anterior dorsal margin gently sloping, as a rule, though 

approaching a parallel with the straight base line. 

Umbones low, inconspicuous, opisthogyrate, placed between half and two-thirds of the distance toward the 

posterior margin. Posterior flexure feeble. Faint concentric groovings visible near the ventral margin, obsolete in the umbonal region. Ligament external, opisthodetic; nymphs elongate. Dentition similar to but 

slightly stronger than that of Tellina declivis—a simple 

and a bifid cardinal in both right and left valves, and a 

strong anterior and an inconspicuous posterior lateral 

in the right valve only. Faint internal radiations but 

no thickened fold. Muscle scars and pallial sinus obliterated in the majority of individuals. Anterior 

muscle impression irregular and somewhat elongated; 

posterior semielliptical. Dorsal margin of pallial sinus 

marked by wavy line, which reaches its maximum elevation beneath the umbones, then descends more gradually, almost but not quite reaching the anterior scar.

T. sayi Deshayes is identified with the Recent fauna 

and has only a meager representation in the North 

Carolina Pliocene. It is well characterized among its 

Tertiary congeners by the moderately low height and 

the obliquely produced and truncated posterior end.

T. (Moerella) piesa Gardner, abundant and widespread in the Shoal River formation of northern Florida, is perhaps a precursal form. Mansfield, 1932, has

noted the similarity of piesa to his subspecies, T. sayi 

deadenensis from the Area and Cancellaria zones of 

the Choctawhatchee formation. The Recent species is 

a little higher relatively than either of the fossil forms.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff, Bladen County; Neills Eddy Landing, .3 

miles north of Cronly, Columbus County.

Outside distribution: Pliocene, Waccamaw formation, Waccamaw River, S. C. Caloosahatchee marl, Caloosahatchee River, 

Fla. Croatan sand, Slocums Creek, Craven County, N. C. 

Pleistocene, Simmons Bluff, S. C.; Rose Bluff, St. Marys River, 

Nassau County, Fla. Recent, North Carolina to Yucatan.

Tellina (Moerella) dupliniana Dall

1900. Tellina (Angulus) dupliniana Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 5, p. 1032, pi. 46, fig. 17. . 

1900. Tellina (Angulus) propetenella Dall, idem, vol. 3, pt. 5, p.

1033, pi. 46, fig. 6. 

1904. Tellina (Angulus) dupliniana Dall. Glenn, Maryland

Geol. Survey, Miocene, p. 299, pi. 73, fig. 1.

Shell small, solid, rather convex, inequilateral, dorsal margins 

rectilinear, diverging at an agle of about 108°, anterior end 

longer, rounded evenly into the base, which is nearly parallel 

with the anterior dorsal margin; posterior end much shorter, 

pointed, the terminal angle slightly decumbent and the basal 

margin in front of it slightly incurved; beaks incouhtileuous, 

hinge normal, the right adjacent lateral short and the anterior 

hinge margin in front of it grooved for the edge of the Opposite 

valve; middle of the disk smooth—the beaks, posterior dorsal 

area, and the portions of the disk near the basal margin more 

or less concentrically striated; interior with the pallial sinus 

rising to a small angle under the umbo, then descending in a 

somewhat wavy line to a point on the pallial line considerably 

short of the anterior adductor scar; in the left valve the sinus 

is not angulated above and extends somewhat nearer the 

adductor; the interior is marked with some faint radiations 

near the adductors, but no thickened ray appears. Longitude 

12.5, altitude 8, diameter 4 millimeters.

There is some little difference in the proportional height in' 

different individuals, in the amount of inflation, and in the 

arcuation of the posterior dorsal margin; the posterior fold, or 

ridge bounding the posterior dorsal area, is not strongly marked. 

Compared with T. tenella Verrill, this species is a heavier and 

higher shell, with the posterior end more^ pointed and decurved. 

The dorsal margin of the right valve is not grooved in T. tenella, 

and the adjacent lateral is longer than in T. dupliniana of the 

same size.—-Dall, 1900.

Holotype: U. S. Nat. Mus. 115040.

Type locality: Magnolia, Duplin County, N. C. 

Duplin marl.

T. dupliniana Dall is a compact and solid little 

species that displays a rather remarkable series of 

variations in the degree of convexity, posterior flexture, 

and general form—particularly in respect to the inclination of the anterior and dorsal margins to the 

base and the outline of the posterior margin—and, to 

a limited extent, even in the dentition, notably in the 

prominence of the anterior right lateral.

A constant peculiarity of the hinge separates the 

form from all the coexistent Tellina with which in some 

of its various manifestations it might easily be confused. This is the position of the anterior right lat-
PART 1. PELECYPODA 97

eral, which instead of being a little dorsal to the 

cardinal, as in the majority of Moeretta, is in a direct 

line with it.

T. propetenella Ball (U. S. Nat. Mus. 144850) is 

synonymous with T. dupliniana. The forms separated 

under that name are slightly smaller than the average 

dupliniana and are more uniform in outline, but they 

have no characters by which they can be distinguished 

even subspecifically. Much more worthy of separation 

are forms from Robeson County, most of which are 

unusually high and heavy individuals, strongly flexed 

posteriorly, with the posterior margin somewhat produced and with remarkably strong and prominent 

teeth. As these characters are exhibited in a greater 

or less degree, both individually and collectively, at a 

number of widely separated localities, it has seemed 

unnecessary and undesirable to subdivide the species.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, and 1 mile below Yorktown, York County; 5% miles 

northwest of Smithfield, and % mile northeast of Smithfield, 

Isle of Wight County: Sycamore, Southampton County; 1% 

miles southeast of Reics Perry, 1% miles north of Suffolk, 1% 

miles north of Suffolk, l1/^ miles northeast of Suffolk, 1 mile 

northeast of Suffolk, and % mile below the Suffolk waterworks dam, Nansemond County.

North Carolina: M locene, Yorktown formation, Palmyra 

Bluff, Halifax County; 2 miles west of Rocky Mount, 5 miles 

below New Bridge on the Tar River, Edgecombe County; 

Jacobs Branch (2 miles southeast of Tugwell), 3 miles south 

of Parmville, 8 to 9 riiles south of Greenvile, 9 to 10 miles 

south of Greenville, a ad 2 miles east of Grifton (on J. F. 

Brooks' land), Pitt County; 1 mile west of Wilson (in Hominy 

Swamp, on Prank Ba:'nes' land), Wilson County; 1% miles 

below Tar Perry, Wiccacon Creek, and 3 to 4 miles below Tar 

Ferry, Hertford Count 7; Colerain Landing and % to % mile 

above Edenhouse Point, Bertie County; Rock Landing, Craven 

County. Duplin marl, 4 miles south of Clinton (on J. L. 

Mathis' farm), Sampson County; Natural Well, l1/^ miles north 

of Magnolia, and the :narl pit of W. H. Kornegay near Magnolia, Duplin County; 1 mile west of Lumberton (on the farm 

of Charles Rowland), Lumberton (near the bottling works), 

2 miles below Lumberton, 4 to 5 miles below Lumberton, 4 miles 

northeast of Pairmont (on the farm of D. E. Lewis), and 1% 

miles northeast of Fairmont (on the farm of Andrew Jones), 

Robeson County. Pliocene, Wncoamaw formation, 4 miles south 

of Elizabethtown on i-Iammoml Creek (on the land of Mrs. 

Clark), and Walkers Bluff, Bladen County; Lake Waccamaw, 

Cronly (i£ mile east of the factories), and Neills Eddy Landing (3 miles north of Cronly), Columbus County; Wilmington, 

New Hanover County.

Outside distribution : Miocene, Calvert formation, Plum Point, 

Gal vert County, Md. (Dall). Pliocene, Waccamaw formation, 

Tillys Lake. Waccamaw River, S. C. Caloosahatchee marl, 

Caloosahatchee River, Fla.

Tellina (Moerella) macilenta Ball

Plate 17, figure 5

1900. Tellina (Angulut) macilenta Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 5, p. 1034, pi. 46, fig. 20. 

1919. Tellina (Angulur.) macilenta Dall. Gardner and Aldrich,

Acad. Nat. Sci. Philadelphia Proc., vol. 71, p. 19.

(Check list of fossils frpm Muldrow Place, S. C.)

1932. Tellina (Moerella) macilenta Dall. Mansfield, Florida 

Geol. Survey Bull. 8, p. 137, pi. 27, figs. 10-12.

Shell solid, subtrigonal, moderately convex, equivalve; inequilateral ; anterior end longer,< rounded, posterior roundly 

pointed near the base; beaks pointed, dorsal margins slightly 

arched; surface polished, faintly distantly concentrically striated ; near the basal margin the striae become regular and 

more sharp and conspicuous; posterior dorsal area nearly 

smooth, posterior end not folded, but slightly flexed; hinge 

normal, adjacent lateral short, strong and prominent; pallial 

sinus somewhat arched above, long, wholly confluent below; 

interior more or less radially striate; in the' left valve the 

thickened rays inside the adductor scars are obvious. Longitude 16.5, altitude 10.5 [10.8], diameter 5.5 milometers.

This form is not intimately related to any of the recent 

species and is easily discriminated by its solid subtrigonal 

valves, size, and shortness from any of the Miocene species.— 

Dall, 1900.

Holotype> a right valve: U. S. Nat. Mus. 115045.

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl.

Mansfield records the species from the Cancellaria 

zone of the Choctawhatchee formation.

Distribution: North Carolina: Miocene, Yorktown formation, 

2^ miles northwest of Williamston (on Joseph Cherry's farm), 

Martin County; 1 mile east of Lizzie (on T. N. Lassiter's 

farm), Greene County. Duplin marl, Natural Well, 1% miles 

north of Magnolia, Duplin County; 2 mile^s below Lumberton 

and 1% miles northeast of Pairmont (on Andrew Jones' farm), 

Robeson County. Pliocene, Waccamaw formation, Walkers 

Bluff, Bladen County.

Tellina (Moerella?) verdevilla Gardner, n. sp.

Plate 17, figures 6, 7

Shell thin, ovate, subcuneate posteriorly, flexuous. 

Posterior fold indistinct, emphasized by depression in 

front of it. Umbones low, inconspicuous, slightly opisthogyrate, posterior. Lunule narrow, elongated, clearly delimited. Anterior dorsal margin gently sloping; 

lateral margin broad, evenly rounded. 'Posterior end 

obliquely truncated. Dorsal slope steep, margin expanding slightly below the nymph. Base arcuate, 

somewhat contracted posteriorly. Surface sculptured 

with microscopic concentric striations and stronger incrementals. Hinge characters of only the right valve 

known. Ligament external, opisthodetic; nymph sublinear, a deep groove at its ventral margin. Anterior 

cardinal short, laminar; posterior cardinal deeply sulcated; both the anterior and posterior laterals prominent, subspinose, separated from the margins by deep 

grooves. Traces of an inner posterior ray faintly visible in one of the two valves. Adductor impressions 

very feeble. Pallial line indistinct. Sinus moderately 

broad, the dorsal margin slightly bowed beneath the 

umbones, the ventral margin confluent with the pallial 

line, rather shallow for the genus, extending only about 

two-thirds of the distance toward the anterior margin.

Dimensions of holotype: Height 13.8 millimeters, 

width 20.0 millimeters, convexity 3.6 millimeters. Par-
98 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

atype: Height 15.0 millimeters, width 21.0 millimeters.

Holotype and paratype, both right valves: U. S. 

Nat. Mus. 325596.

Type locality: 6 miles below Greenville, Pitt County, 

N. C. Yorktown formation.

Tellina verdevilla, n. sp., is sharply separated from 

all members of the Moerella group, which it most closely 

resembles in the external characters, by the strong posterior lateral in the right valve. The outline recalls 

Moerella madlenta Dall, but the hinge is less concentrated and the anterior lateral more isolated. In most 

of the Moerellae the groove separating the anterior cardinal and the dorsal margin is continuous with the 

lateral socket. In verdevllla the groove is extremely 

shallow medially.

Distribution: North Carolina: Miocene, Yorktown formation, 

6 miles below Greenville, Pitt County.

Tellina (Moerella?) calpix Gardner, n. sp.

Plate 17, figures 2, 3

Shell thin, oval, rather compressed, slightly contracted posteriorly, almost but not altogether equilateral. Umbones low, flattened, opisthogyrate, situated a 

little behind the median line. Both anterior and pobterior dorsal and distal margins rounded; the anterior 

end slightly broader, higher, and more evenly arched; 

the posterior with a tendency toward an obscure truncatou: Base line gently arched. Posterior flexure 

indistinct. Concentric groovings discernible only on 

the anterior end and near the ventral margin. Valves 

faintly radiate within, but not noticeably thickened. 

Ligament external, attached to narrow, elongated 

nymphs. Dentition of right valve only known, similar 

to that of Tellina, declivis Conrad; posterior bifid and 

anterior simple cardinals rather slender. Anterior lateral of moderate strength, situated a little dorsal to the 

anterior cardinal; posterior lateral low and small; 

lateral grooves extending for some distance toward the 

base before becoming entirely obsolete. Posterior 

muscle impression subcircular; anterior irregular, 

longer than broad. Pallial sinus very indistinct, more 

regular than in most of the group, ascending from a 

point about halfway down the anterior side of the 

posterior adductor impression to a point underneath 

the umbones and level with the dorsal boundary of the 

posterior scar, then descending gradually in a regular 

line and just clearing the anterior adductor.

Dimensions of holotype: Height, 8,0 millimeters, 

width 11.5 millimeters, convexity 2.0 millimeters.

Holotype a right valve: U. S. Nat. Mus. 325595.

Type locality: Eight to 9 miles south of Greenville, 

Pitt County, N C. Yorktown formation.

The shell is remarkable for its regularly rounded, 

oval form, its subcentral umbones, and the absence of 

the posterior angulation. It is apparently most closely 

related to T. declivis Conrad, from which it differs in

being more nearly equilateral and more rounded, both 

anteriorly and posteriorly. The outline suggests a 

miniature Macoma, but the development of laterals in 

the right valve throws it out of that genus. A knowledge of the left valve is necessary for the assured 

placement of the species within the proper subgeneric 

group.

Distribution: North Carolina: Miocene, Yorktown formation, 

3y2 miles below Palmyra Bluff, Halifax County; 8 to 9 miles 

south of Greenville and 9 to 10 miles south of Greenville, Pitt 

County.

Tellina (Subgenus uncertain) egena Conrad

Plate 17, figure 1

1834. Tellina egena Conrad, Acad. Nat. Sci. Philadelphia Jour.,

1st ser., vol. 7, p. 131. 

1840. Tellina, egena Conrad, Fossils of the medial Tertiary of

the United States, p. 35, pi. 19, fig. 2. 

1900. Tellina (Peronidiaf) egena Conrad. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 5, p. 1029.

Shell subtriangular, convex, with fine, crowded, concentric 

lines and obscure, radiating striae; anterior margin oblique, 

rectilinear; extremity subangulated; dorsal margin but little 

arcuated; lateral teeth none. Length, 2^ inches. 

Locality, James River, Va.—Conrad, 1834.

It is strange that a form so conspicuously largo 

should not have been recorded from some of the later 

collections.

Dall referred T. egena to Peronidia, a group characterized by the absence of laterals. The type has not 

been examined.

Genus MACOMA leach

1819. Macoma Leach. Ross, John, A voyage of discovery made 

under the orders of the Admiralty in His Majesty's 

ships Isabella and Alexander for the purpose of exploring Baffin's Bay and inquiring into the probability 

of a northwest passage, App. 2, p. 62.

1819. Macoma Leach, Jour, physique, vol. 88, p. 465.

Type by monotypy: Macoma> tencra Leach = Tellina icalcarea 

Gmelin. Recent in the North Atlantic and Arctic Oceans.

Outline transversely ovate or subtrigonal, strongly 

flexuous, as a rule, posteriorly. External surface 

smooth or feebly sculptured concentrically. Two divergent cardinals in each valve. Laterals absent. 

Pallial sinus often discrepant in the two valves, varying 

widely within the limits of the genus.

The genus is fairly common from the Miocene on 

and is represented in the Recent seas by about 100 

species. Though not restricted to the cooler waters, 

the typical members are characteristic of the higher 

latitudes.

Macoma virginiana (Conrad) Dall

Plate 17, figures 9, 10

1840. Tellina lusoria Conrad, Fossils of the medial Tertiary of 

the United States, p. 35, pi. 19, figr 3. Not PsammoUaf 

lusoria Say, 1822.
PART 1. PELECYPODA 99

1856. Tellina lusoria Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 89, pi. 22, fig. 5. 

1858. Tellina lusoria, Emmons?, North Carolina Geol. Survey

Kept., p. 297, f g. 225a. 

1863. Tellina (Peronaederma) lusoria? Say. Conrad, Acad.

Nat. Sci. Philadelphia Proc. for 1862, p. 573. 

1866. Macoma virgmiana Conrad, Am. Jour. Conchology, vol. 2,

p. 76. 

1900. Macoma virginiana Conrad. Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 5, p. 1048.

Shell elliptical, with a distinct fold near the posterior extremity ; posterior end reflected; posterior dorsal margin 

straight, oblique, extremity truncated and much above the line 

of the base; beaks nearest the posterior end; basal margin 

very regularly arched; lateral teeth none.

Locality, Yorktown, Va.—Conrad, 1840.

This species is extinct and may be distinguished from M. 

lusoria, by being proportionally more elevated, rounded at base, 

and less compressed and reflexed anteriorly.—Conrad, 1866.

After repeated studies of the subject I have come to the 

conclusion that Say's Psammo'bw, lusoria was probably based on 

a large specimen of the shell, which he afterwards described 

under the name of Tellina tenta. From that species the present 

shell differs, as Conrad states it does from lusoria, by being 

higher, more arcuate below, and less compressed and flexuous 

behind; it also averages considerably larger. The pallial sinus 

is low, rather short, rounded in front, and about half confluent 

with the pallial line below. There is some doubt as to whether 

the shell figured by Emmons is the same, as he speaks especially 

of sharp, elevated lines on the surface, which I have not 

observed on any of the Virginia shells.—Dall, 1900.

Shell thin, inflated, slightly inequivalve, the right 

valVe a trifle higher than the left, inequilateral, the 

anterior end semielliptical, its dorsal margin subparallel to the base, and the lateral margin broadly and regularly rounded. Posterior end shorter, attenuated, 

the dorsal margin slightly contracted beneath the umbones, and the dorsal and ventral margins converging 

at a low angle, obscurely truncated distally. Umbones 

posterior, opisthogyrate. Surface feebly sculptured 

with incremental. Ligament external, opisthodetic, 

seated, on a very narrow and rather elongated 

nymph. Hinge armature of right valve a rather stout, 

simple, anterior cardinal and a rather slender, bifid, 

posterior cardinal. Left valve with a bifid anterior 

and a very slender, almost laminar, posterior cardinal. No laterals developed in either valve. Interior faintly striated radially. Anterior adductor 

scar irregularly elongated; the posterior, semielliptical. Pallial sinus broad, rounded, often slightly 

arched just beneath the umbones, extending about twothirds of the distance across from the posterior to the 

anterior margin.

Dimensions of figured specimen: Height 12.3 millimeters, width 19.8 millimeters.

Figured specimen, a right valve: U. S. Nat. Mus. 

325594, from 1 mile northeast of Suffolk, Va. Yorktown formation.

Though the inequality of the valves is very slight, 

it is sufficient to make a noticeable difference in their

general aspect; in the right valve there is a tendency 

toward a perceptible flare in the anterior dorsal margin; in the left valve the anterior dorsal and ventral 

margins are more nearly parallel. The species is well 

characterized by the nasute aspect of the posterior 

portion of the shell. This feature is absent in M. carolinensis Gardner and Aldrich, the closely related form 

south of the Hatteras axis, for in the latter the posterior dorsal margin declines at a uniform and rather 

steep angle, and the lateral margin is evenly rounded 

and merges gradually into the base line.

Macoma virginiana Conrad is fairly common, particularly in the Yorktown formation of the State from 

which it takes its name. Mansfield has described a 

subspecies coensis from the Cancellarid zone of the 

Choctawhatchee formation, which differs both from 

M. virgmiana and from the subspecies conradi by the 

more tapering posterior extremity.

Distribution: Virginia: Miocene, St. Marys formation, 1 to 2 

miles below Bowlers Wharf, Essex County. Yorktown formation, Yorktown, 1 mile below Yorktown, and 1% miles below 

Yorktown, York County; mouth of Baileys Creek, Prince 

George County; 7 to 7% miles below1 Zuni, 1% miles northeast 

of Smithfield, and % mile northeast of Smithfield, Isle of 

Wight County; 1% miles southeast of Reiids Ferry, iy2 miles 

north of Suffolk, 1% miles north of Suffolk, 1% miles northeast of Suffolk, 1 mile northeast of Suffolk, 1 mile east of 

Suffolk, and V2 mile below the Suffolk waterworks dam, Nansemond County.

Macoma virginiana conradi Dall

Plate 17, figure 22

1900. Macoma conradi Dall, Wagner Free Inst. Sci. Trans., vol. 

3, pt. 5, p. 1048, pi. 47, fig. 3.

Shell thin, inflated, ovate, broad and rounded in front, rapidly 

attenuated, roundly pointed and somewhat flexuous behind; 

beaks low, pointed, near the posterior third; surface smooth or 

marked only with fine incremental lines; hinge normal, feeble, 

teeth small; adductor scars large, pallial sinus short, rounded, 

and curved (in the right valve) well backward below before 

coalescing with the pallial line. Longitude 22 [21.7] altitude 

14, diameter 7 millimeters.

This is a shorter and broader and less flexuous shell than 

If. virginiana Conrad, some of the varieties of which somewhat 

aproach it.—Dall, 1900.

Holotype, a right valve: U. S. Nat. Mus. 144475.

Type locality: Yorktown, Va. Yorktown formation.

The characters that separate the type of conradi 

from M. virginiana s. s. are of degree rather than kind, 

and an unbroken series connecting the two forms can be 

established. The individuals from the Carolinas that 

have been referred to this species are, however, distinct, 

and the same diagnostics that are used to separate 

virginiana s. s. and carolinensis—that is, the nasute 

posterior end and the broader but more shallow pallial 

sinus of the former—are shared by the subspecies as 

well.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Exit, 1% miles northwest of Suffolk, and 

1 mile northeast of Suffolk, Nansemond County,
100 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

North Carolina: Miocene, Yorktown formation, Colerain 

Landing on the Chowan River, Bertie County.

Macoma carolinensis Gardner and Aldrich

1919. Macoma carolinensis Gardner and Aldrich, Acad. Nat. Sci. 

Philadelphia Proc., p. 50, pi. 3, figs. 5-7.

Right valve, altitude 12.3 millimeters, latitude 18.2 millimeters, semidiameter 4.3 millimeters. Left valve of another 

individual, altitude 12.5 millimeters, latitude 19.5 millimeters, 

semidiameter 3.3 millimeters.

Type locality: Darlington, S. C. Duplin Formation.

Macoma carolinensis is the analogue in the Neogene south 

of the Hatteras axis of M. virainiana and its subspecies conradi 

north of the axis. It is rather higher, less flexuous, and more 

nearly equilateral than either of the former, both by reason 

of the more nearly central umbones and the greater similarity 

of the anterior and posterior extremities. The posterior dorsal 

margin of If. carolinensis has a uniform, fairly steep slope, 

while that of M. virginiana is slightly contracted directly behind 

the umbones, then obliquely produced at a very low angle. 

The posterior lateral margin of the former is rounded into 

the slightly upturned base; that of the latter, obscurely truncated and its ventral margin more strongly recurved. The 

pallial sinus in both species varies quite widely but that of 

carolinensis is, on the average, more profound and more 

strongly arched beneath the umbones.

The species is rare in the Duplin and Waccamaw formations 

of North and South Carolina.—Gardner and Aldrich, 1919.

Distribution: North Carolina: Miocene, Duplin marl, 2 miles 

below Lumberton, Robeson County. Pliocene, Waccamaw 

formation, Mrs. Guion's marl pit, Cape Fear River, Bladen 

County.

Outside distribution: Pliocene, Caloosahatchee marl, Caloosahatchee River, Fla.

Macoma cookei Gardner, n. sp.

Plate 17, figures 8, 11

Shell relatively large, irregular in outline; rather 

thin, flexuous; anterior half of shell moderately inflated, posterior somewhat depressed. Posterior fold 

obscure, evanescent toward the ventral margin. Umbones set a little in front of the median line, rather 

low and inconspicuous, their tips acute. Anterior end 

somewhat eccentric, slightly flarfng dorsally, obscurely 

and obliquely truncated medially; strongly arcuate 

toward the ventral margin; posterior end somewhat 

produced and attenuated. Surface sculptured with 

fine, irregular concentric striations. Ligament opisthodetic; nymph narrow elongated, rather surprisingly 

robust. Hinge armature of right valve reduced to a 

couple of short, feeble cardinals, divergent beneath the 

umbones. Muscle impressions irregular, distinct, the 

anterior submedial and rudely elongated, the posterior 

roughly quadrate. Pallial sinus of right valve coalescent ventrally with pallial line, upcurved dorsally, 

its maximum elevation a little above the median 

horizontal and directly beneath the umbones, its frontal 

margin overreaching the median vertical but falling 

short of the anterior adductor, Pallial line moderately 

distinct,

Dimensions of holotype: Height 28.0 millimeters, 

width 34.3 millimeters, convexity 7.1 millimeters.

Holotype, a right valve: U. S. Nat. Mus.-325592.

Type locality: Yorktown, York River, Va. Yorktown formation.

Macoma cookei is described from a single valve collected at the type locality of the Yorktown formation. 

This relatively large and elevated shell has, however, 

little but the generic characters in common with its small 

and transversely elongated congeners. In outline and 

general aspect it most closely resembles M. baltMca Linnaeus of the Pleistocene and Recent faunas. The 

Yorktown species is larger, however, and has a much 

stronger dentition.

I have the pleasure of naming the form in honor of 

Dr. Wythe Cooke, whose name has long been associated 

with the Lower Tertiary faunas of the Gulf region.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County.

Family SEMELIDAE Ball

The family is most readily separable from the Tellinidae by the presence of an internal resilium.

Genus SEMELE Schumacher

1817. Semele Schumacher, Essai d'un nouveau systeme des 

habitations des vers testaces, p. 165.

Type by monotypy: Tellina fetlculata Spengler=TeMwa 

proflcua Pulteney. Pliocene of South Carolina and Florida and 

living from Virginia to Fernando de Moronha and east to 

Bermuda in less than 50 fathoms.

Shell oval or suborbicular, slightly inequivalve, 

usually more or less rostrate posteriorly. Umbones 

subcentral, low, proximate, prosogyrate. Ligament 

short, external; resilium strong, internal. Hinge armature consisting of 2 cardinals and 2 laterals in • each 

valve, the laterals of the right valve usually stronger. 

Adductor impressions large, semielliptical. Pallial 

sinus profound.

The genus is represented in the Tertiary formations 

by some 30 species, many of them very attractive, and 

in the Recent waters by about 60 species, most of them 

tropical.

Section SEMELE s. s.

Semele s. s. includes the relatively large members of 

the genus. The sculpture may be radial and concentric, 

reticulate, or undeveloped. The chondrophore is 

obliquely elongated, the laterals of the left valve are 

feeble but present, and the left posterior cardinal is 

slender and laminar.

Semele subovata (Say) Dall

1824. Amphidesma subovatd Say, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 4, p. 152, pi. 10, fig. 10.

1840. Amphi&esma svlovata Say. Conrad, Fossils of the medial 

Tertiary of the United States, p. 36,
PART 1. PELECYPODA 101

1854. Syndosmya subobliqua Conrad, Acad. Nat. Sci. Philadelphia Proc., vol. 7, p. 29 (lapsus for subovata).

1862. Abra ovalis Conrad, Acad. Nat. Sci. Philadelphia Proc. for 

1862, p. 288.

1863. Abra (AmpMdesma) subovata, Say. Conrad, idem, p.

574. 

1900. Semele subovata Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 5, p. 990. 

1900. Semele bella Conrad. Dall, idem, vol. 3, pt. 5, p. 990.

Not Semele bella, Conrad, 1875. 

1904. Semele subovata (Say). Glenn, Maryland Geol. Survey,

Miocene, p. 295, pi. 72, figs. 6, 8. 

1909. Semele subovata (Say). Grabau and Shimer, North

American index fossils, vol. 1, p. 568, fig. 780a.

Shell transversely ovate-oval, with somewhat prominent 

and regular concentric striae.

Shell compressed; beaks rather before the middle, but little 

prominent; anterior submargin with an obsolete, obtuse undulation ; lunule lanceolate; cardinal and lateral teeth prominent.

Length seven-tenths of an inch, breadth less than 1 inch.— 

Say, 1824.

Type locality: Maryland.

This is a common species of the Virginia Miocene, separable 

from the S. oarinata—which is almost equally common—by its 

more oval and thinner shell and finer, sharper, and closer concentric sculpture. The posterior dorsal area is usually conspicuously sculptured, whereas in S. carmata the tendency of the 

sculpture on this area is to become obsolete.—Dall, 1900.

Say has confused the anterior and posterior portions 

of the valve. The beaks are subcentral or slightly posterior, and the obtuse undulation is on the posterior 

and not the anterior area.

The examination ef a long series of individuals from 

a number of localities in the Virginia and North Carolina Miocene indicates that all the elongate-oval to subtriangular Semeles ornamented solely with close 

concentric laminae of approximately equal strength are 

referable to this single species.

The three subspecies are based on variations in the 

outline and in the number and character of the concentric laminae and on the persistence or nonpersistence 

of the sculpture across the posterior keel.

Semele subovata (Say) is separated from S. carinata 

(Conrad) by the absence of secondary concentric ornamentation; from 8. 'bellmtnata (Conrad) by the absence of radial ornamentation. In weathered individuals erosion has often acted on the striae differently, 

partly obliterating some; whereas others retain their 

original prominence and thus give to the form the 

aspect of a more distantly sculptured species.

The resemblance to S. carinata (Conrad) is embarrassingly close where faint traces of the lost lirations 

still persist. The original sculpture usually may be 

caught on the lateral margins, however, even though it 

is removed from the disk.

Distribution: Virginia: Miocene, St. Marys formation, Union 

Mill, 2y2 miles south of Farnham, Richmond County; Urbanna, 

Middlesex County. Yorktown formation, Yorktown, Bellefleld, 

York County; Petersburg, Dinwiddie County; Claremont Wharf

(upper bed), Surry County; Fergusons Wharf, % mile northeast of Smithfield, Benns Church; 1,4 mile north of Chuckatuck, 

1% miles southeast of Reids Ferry, 6^ miles below Zuni 

and 12 to 14 miles below Zuni, Isle of Wight County; Sycamore, 

% to V2 mile below Sycamore, Maddelys Bluff, and % to % 

mile above the lower Seaboard Railway bridge over the Meherrin River, Southampton County; \% miles northeast of Suffolk, 

1 mile northeast of Suffolk, 1 mile west of Suffolk, % mile below 

the Suffolk waterworks dam, and the drainage ditch of the 

Norfolk & Western Railway just east of Jericho ditch, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1 mile above 

Murfreesboro, Hertford County; % mile above Bells Bridge 

over the Tar River, and Swift Creek, Edgecombe County; 2 

miles southeast of Tugwell, 9 to 10 miles south of Greenville, 

Hardeeig Creek (S1/^ miles from' confluence with Tar River), 

and 1 mile northwest of Galloway Crossroads, Pitt County; 2 

miles north of Lizzie and 4 miles east of Lizzie, Greene County; 

Colerain Landing, Bertie County. Duplin marl,, 1^ miles 

northeast of Fairmont, Robeson County.

Outside distribution: Miocene, Galveston well (at 2,552 to 

2,600 feet), Texas. Calvert formation, Centerville and Church 

Hill, Queen Annes County, Md.; Fairhaven, Anne Arundel 

County, Md. Choptank formation, Governor Run, Calvert 

County, Md.; Greensboro, Caroline County, Md.; Cordova, Peach 

Blossom Creek, and Dover Bridge, Talbot County, Md.; Jones 

Wharf, St. Marys County, Md.

Semele subovata alta Gardner, n. subsp.

Plate 17, figures 16, 17

Shell high, ovate to subtrigonal. Somewhat compressed posteriorly. Produced, rounded, and slightly 

inflated anteriorly. Umbones placed a little behind 

the median line. Anterior dorsal slope gentle, posterior more pronounced, in certain individuals gently 

arched; anterior lateral margin evenly rounded. Base 

line arcuate, posterior sinus shallow, often obsolete. 

Concentric sculpture fine, close, and lirate, or lamellar.

The other characters are shared by all members of 

the species.

Dimensions of holotype: Height 21.0 millimeters, 

width 26.3 millimeters, diameter 11.3 millimeters.

Holotype (double valves) : U. S. Nat. Mus. 325582.

Type locality: 2 miles northeast of Lizzie, Greene 

County, N. C. Yorktown formation.

The subspecies is relatively higher than other members of the species, and its sculpture is finer, closer, and 

less commonly lirate. It has a tendency, furthermore, 

toward a larger size and a more pronounced inflation 

of the anterior portion of the valves.

Distribution: Virginia: Miocene, St. Marys formation, Urbanna, Middlesex County. Yorktown formation, Yorktown, York 

County; Zuni (near the pumping station) and 6% to 7 miles 

below Zuni, Isle of Wight County; iy2 miles north of Suffolk, 1% 

miles northeast of Suffolk, and 1 mile northeast of Suffolk, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, Palmyra Bluff, 

Halifax County; 1 mile northwest of Galloway Crossroads, 

Pitt County; 2 miles northeast of Lizzie, Greene County; Colerain Landing, Bertie County. Pliocene, Waccamaw formation, 

Wilmington, New Hanover County.
102 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Semele bellastriata (Conrad) Ball

Plate 17, figures 27, 28, 32, 33

1837. AmpMdesma bellastriata Conrad, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol 7, p. 239, pi. 20, fig. 4.

1845. AmpMdesma cancellata D'Orbigny. Sagra, Historia fisica 

politica y natural de la Isla de Cuba, pt. 2, vol. 5, p. 

297, pi. 25, figs. 42-44.

1847. AmpMdesma cancellata D'Orbigny. Sagra (French ed.), 

Histore Physique, Politique et Naturelle de L'lle de 

Cuba, Mollusques, vol. 2, p. 241; Atlas, pi. 25, figs. 42-44.

1862. Semele nexilis Gould, Boston Soc. Nat. History Proc., 

vol. 8, p. 281.

1862. Semele nexilis Gould, Otia conchologica, p. 238.

1873.. Semele nexilis Gould. Tryon, American marine conchology, p. 155.

1875. Abra l)ella Conrad. In Kerr, Geol. Survey North Carolina, Kept, App. A., p. 19, pi. 3, fig. 4.

1883. Semele nexilis Gould. Ball, U. S. Nat. Mus. Proc., vol 6, 

p. 338.

1885. Semele lata C. B. Adams. Bush, Connecticut Acad. Arts 

and Sci. Trans., vol. 6, pt. 2, p. 476.

1889. Semele cancellata D'Orbigny. U. S. Nat. Mus. Bull. 37, 

p. 62.

1900. Semele bellastriata Conrad. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, p. 993.

1932. Semele bellastriata (Conrad)? Mansfield, Florida Geol. 

Survey Bull. 8, p. 145, pi. 32, fig. 3.

Shell elliptical, compressed; anterior margin very regularly 

rounded; posterior side with a slight fold; disk with numerous 

prominent, not very regular, concentric striae and obscure 

radiating lines, which are profound near the anterior and posterior extremities; beaks rather nearer the posterior extremity; 

lateral teeth prominent, distinct in both valves; margin entire.

Inhabits Mobile Point, Ala. Occurs sparingly in the Newer 

Pliocene marl, near Newbern, N. C.—Conrad, 1837.

Mansfield reports the doubtful occurrence of the 

species in the Ecphora zone of the Choctawhatchee 

formation.

The figured specimens are U. S. Nat. Mus. 325583, 

from the Waccamaw formation at Neills Eddy Landing 

on the Cape Fear River, Columbus County, N. C. The 

dimensions of the right valve are height 13.2 millimeters, width 18.3 millimeters; of the left valve, height 

14.5 millimeters, width i9.0 millimeters.

Abra bella of Conrad is a reticulately sculptured 

form synonymous with his AmpMdesma bellastriata 

of 1837. The two varieties of Dall, duplinensis and 

appresa, were founded on individuals from the North 

Carolina Duplin marl that exhibit no radial sculpture 

but show peculiarities in the concentric sculpture. 

These same features are developed, though less commonly, in the subovata of Virginia, and complete gradations to the normal form occur in both States.

k

Distribution: North Carolina: Pliocene, New Bern, Craven 

County? (Conrad). Waccamaw formation, Walkers Bluff, 

Bladen County; Cronly and Neills Eddy Landing (3 miles 

north of Cronly), Columbus County,

Outside distribution: Pliocene, Waccamaw formation, Nixons 

and Tillys Lake, Horry County, S. C. Caloosahatchee marl, 

Caloosahatchee River and Shell Creek, Fla. Recent, Cape Hatteras to Cape St. Roque and east to Bermuda in less than 50

fathoms except off Hatteras, where it occurs in both shallow 

and deep water.

Section SEMELINA Dall

1900. Semelina Dall, Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, 

p. 986.

Type by original designation: Semelina nuculoides Conrad. 

Upper Miocene of Virginia and North Carolina, Pliocene (Caloosahatchee) of Florida, Recent from Hatteras to the West 

Indies.

Shell small, nuculiform; sculpture uniform, close, concentric; 

chondrophore short; left valve without distinct laterals, the 

dorsal margins fitting above the laterals of the right valve; 

left posterior cardinal absent or obsolete, the anterior cardinal 

bifid; otherwise as in Semele s. s.

The species of this section are very similar to one another 

and have extended from the Oligocene through all the Tertiary 

horizons to the present fauna. For this reason it seems worthy 

of sectional rank. The characters by which the shell differs 

from Semele proper are only such as are usually correlated 

with diminished size.—Dall, 1900.

An exceedingly thin and laminar left posterior cardinal is developed in both the Alum Bluff species. In 

most individuals it is broken, but in a few it is 

preserved entire.

Semele (Semelina) nuculoides (Conrad) Dall

Plate 17, figures 18, 19, 20, 21

1841. AmpMdesma nuculoides Conrad, Am. Jour. Sci., 1st ser., 

vol. 41, p. 347.

1845. AmpMdesma nuculoides Conrad, Fossils of the medial 

Tertiary of the United States, p. 73, pi. 41, fig. 6.

1863. Abra nuculoides Conrad, Acad. Nat. Sci. Philadelphia Proc. 

for 1862, p. 574.

1889. Semele nuculoides Conrad. Dall, U. S. Nat. Mus., Bull 

No. 37, p. 62.

1900. Semele nuculoidea Conrad. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, p. 994.

1932. Semele (Semelina) nuculoides (Conrad). Mansfield, Florida Geol. Survey Bull. 8, p. 146, pi. 30, fig. 9.

Ovate, convex, with very regular minute concentric lines; 

anterior extremity acutely rounded; beaks near the posterior 

extremity; basal margin arcuate; lateral teeth obsolete.— 

Conrad, 1841.

Type locality: Wihnington, N. C.

The figured specimens are U. S. Nat. Mus. 325581, 

from the Waccamaw formation at Neills Eddy Landing on the Cape Fear River, Columbus County, N. C. 

The height of the right valve is 3.8 millimeters, the 

width 5.6 millimeters; the height of the left valve is 

4.0 millimeters, the width 5.6 millimeters.

Three valves of Semelina nuculoides are reported by 

Mansfield from the Cancellaria zone of the Choctawhatchee formation.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1 mile northeast of Suffolk, Nansemond 

County.

North Carolina: Miocene, Duplin marl, 4 miles south of Clinton (on the farm of J. L. Mathis), Sampson County; Natural 

Well, drainage ditch just east of railroad 1% miles north of
PART 1. PELECYPODA 103

Magnolia, and W. H. Kornegay's marl pit near Magnolia, 

Duplin County. Pliocene, Waccamaw formation, Walkers Bluff, 

Bladen County; Lake Waccamaw, Cronly, Neills Eddy Landing 

(3 miles north of Cronly), Columbus County; Wilmington, New 

Hanover County.

Outside distribution: Pliocene, Caloosahatchee marl, Caloosahatchee River, Fla. Recent, Cape Hatteras south to the West 

Indies in both deep and shallow water.

Genus ABBA (Leach ms.) Lamarck

1818. Abra, (Leach ms.) Lamarck, Histoire naturelle des animaux sans vertebres, vol. 5, p. 492.

Type by subsequent designation (Herrmannsen, Indicis generum Malacozoorum, vol. 1, p. 1, 1846: Mactra tennis Montagu. 

Recent off the English and Irish coasts.

Most of the European conchologists, including 

Forbes, Hanley, Stoliczka, and Lamy, reject Abra in 

favor of Syndosmya Eecluz, 1843. Lamarck, in listing 

Leach's manuscript name, did not, to be sure, characterize the genus, but he gave a new name to a known 

and recognizable shell, and, as Cossmann 45 pointed 

out, the genotype is beyond question. Whether or not 

Lamarck had it in his mind to create a new genus is not 

the concern of nomenclature.

Shell small, ovate to trigonal, or rudely quadrate 

in outline; rather compressed, flexuous posteriorly. 

Umbones low, subcentral to posterior, prosogyrate. 

Outer surface smooth or finely sculptured concentrically. Internal ligament stronger than the external, 

the chondrophore narrow but produced and deeply 

inset beneath the umbones. Dentition delicate; normally two short simple cardinals developed in each 

valve and the modified dorsal margins of the left valve 

received in the lateral sockets of the right; laterals 

commonly obsolete in the species of trigonal outline. 

Pallial sinus deep, confluent ventrally with the pallial 

line.

The Eecent forms are relatively few but have a wide 

geographic and bathymetric range.

Abra subreflexa (Conrad) Conrad

Plate 17, figures 23, 24, 30, 31

1834. Ampliidesmu subreflexa, Conrad, Acad. Nat. Sci. Philadelphia Jour., 1st ser., vol. 7, p. 133.

1840. Amphidesma subreflexa, Conrad, Fossils of the medial 

Tertiary of the United States, p. 37, pi. 19 (1st ed.), 

fig. 6; (2d ed.), fig. 12.

1863. Abra subreflexa Conrad, Acad. Nat. Sci. Philadelphia Proc. 

for 1862, p. 574.

1900, Abra, subreflewa, Conrad. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 5, 997.

Shell somewhat elliptical, convex, anterior margin descending very obliquely and nearly rectilinearly from the beak; 

extremity subreflected, obtusely pointed; posterior side elongated, margin rounded; anterior basal margin oblique and

45 Cossmann, A. E. M., and Peyrot, A., Conchologie n6og£nique de 

]' Aquitaine, vol. 1, 215, 1909.

nearly parallel with the dorsal margin. Length half an inch.

Locality, Suffolk, Va.—Conrad, 1834.

Shell elliptical; anterior side narrowed, produced, rounded 

at tip, the dorsal line rectilinear; posterior side very short, 

with a rather acute fold, the extremity narrow, but obtuse; 

lateral teeth in the right valve; in the left, none.

Locality, Yorjjtown, Va.—Conrad, 1840.

Dimensions of figured specimens: Right valve, height 

5.6 millimeters, width 10.4 millimeters, convexity 1.8 

millimeters; left valve, height 9.0 millimeters, width 

15.6 millimeters, convexity 2.7 millimeters.

Figured specimens: U. S. Nat. Mus. 325584, the 

right and left valves of different individuals.

Locality of figured specimens: Yorktown formation 

at Colerain Landing, Chowan River, Bertie County, 

N. C.

Mansfield 46 described a subspecies jacksonensis from 

the Ecphora zone of the Choctawhatchee formation. 

In his discussion of the subspecies he noted that Conrad in the first description of Amphulesma subreflexa, 

1834, cited Suffolk, Va., as the type locality. In 1840 

he cited Yorktown. Mansfield remarked that he had 

never found the species at Suffolk and never below 

the lower part of zone 2 of the Yorktown formation.

Shell transversely elongate, strongly inequilateral, 

angulated posteriorly. Umbones low, flattened, opisthogyrate, located about two-thirds of the distance back 

from the anterior end.. Anterior portion of shell 

horizontally produced, rounded laterally; posterior 

dorsal margin strongly oblique, rounding distally into 

a base line that is usually straight and subparallel to 

the anterior dorsal margin, though occasionally slightly 

sinuous behind. Surface smooth, polished. Resilial 

pit deep, oblique, elongated, subparallel to the posterior 

dorsal margin. Lateral margins of right valve 

grooved to receive the modified dorsal margins of the 

left. Pallial sinus evenly rounded, extending forward 

at least two-thirds of the distance toward the anterior 

margin.

The species varies rather widely in relative proportions and in the configuration of the posterior margins. 

Its transversely elongate outline, however, sharply 

separates it from the associated Abra.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Petersburg, Dinwiddie County; mouth of 

Baileys Creek, Prince George County; Claremont Wharf (upper 

bed), and Sunken Marsh Creek (upper bed), Surry County; % 

mtle northeast of Smithfield, Benns Church, and 12 to 14 

miles below Zuni, Isle of Wight County; Sycamore, and % to % 

mile above the lower Seaboard Railway bridge, Southampton 

County; 1% miles southeast of Reids Ferry, 2% miles northwest of Suffolk, 1% miles north of Suffolk, 1% miles northeast 

of Suffolk, 1 mile northeast of Suffolk, and the drainage ditch 

of the Norfolk & Western Railway just east of Jericho ditqh, 

Nansemond County.

46 Mansfield, W. C., Miocene pelecypods of the Choctawhatchee formation of Florida : Florida Geol. Survey Bull. 8, p. 148, pi. 32, figs. 11, 14, 

15,1932.
104 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

North Carolina: Miocene, Yorktown formation, near Murfreesboro, Tar Ferry on Wiccacon Creek (opposite Harrellsville), 1% miles below Tar Ferry, 3 to 4 miles below Tar 

Ferry, Dogwood Landing (on the Chowan River) and Mount 

Pleasant Landing, Hertford County; Colerain Landing, Mount 

Gould Landing, and % to % mile above Edenhouse Point, 

Bertie County; Halifax on Quankey Creek (just below the 

county bridge) and Palmyra Bluff, Halifax County; 3 miles 

west of Williamston and 2% miles northwest of Williamston 

(on Joseph Cherry's farm), Martin County; % mile above Bells 

Bridge, Shiloh Mills, and Tarboro (on L. E. Fountain's farm), 

Edgecombe County; 8 to 9 miles southeast of Greenville and 

9 to 10 miles south of Greenville, Pitt County. The species is 

particularly abundant in the Yorktown of North Carolina.

Abra aequalis (Say) Holmes

Plate IT, figures 12-15

1822. Amphidesma aequaUs Say, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 2, p. 307. 

1830. Amphidesma aequalis Say, Am. conchology, facing pi. 28,

pi. 28 unnumbered lateral figures. 

1845. Amphidesma equalis Say. Conrad, Fossils of the medial

Tertiary of the United States, p. 76, pi. 43, fig. 9. 

1856. Amphidesma, equalis Conrad. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 93, pi. 23, fig. 3. 

1858. Abra aequalis Say. Holmes, Post-Pleiocene fossils of

South Carolina, p. 50, pi. 8, fig. 7. Not Abra aequalis

Whitfield, U. S. Geol. Survey Mon. 24, p.' 80, pi. 14,

figs. 11-15, 1894. 

1863. Abra equalis Say. Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 574. 

1867. Abra nuculiformis Conrad, Am. Jour.. Conchology, vol. 3,

p. 14. 

1900. Abra aequalis Say. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p.« 998. 

1932. Abra aequalis (Say)?. Mansfield, Florida Geol. Survey

Bull. 8, p. 148.

Shell orbicular, slightly oblique, polished, white, with very 

minute and numerous concentric wrinkles near the margin, 

which are obsolete, on the disk and umbo; lateral teeth none; 

primary teeth two in the left valve and one in the other; 

interior ligament cavity subfusiform, as long as the exterior 

ligament.

Length two-fifths of an inch. Inhabits the southern coast.— 

Say, 1822.

This species varies a good deal in outline in the same locality, but southern specimens of the recent shell, especially 

those from Florida, have the anterior dorsal slope less rounded 

and the umbonal angle smaller than those from more northern 

localities. The fossils are generally of this type rather than 

like the more rounded northern recent specimens.—Dall, 1900.

The figured specimens (U. S. Nat. Mus. 325585) 

are from the Yorktown formation on the Chowan 

Eiver, one-half to three-fourths of a mile above Edenhouse Point, Bertie County, 1ST. C. The right valve 

measures 10.6 millimeters in height and 12.0 millimeters in width. The left valve of another individual 

measures 10.5 millimeters in height and 12.0 millimeters 

in width.

The shell is subtriangular to obliquely orbicular in 

outline and is, as a rule, somewhat warped posteriorly. 

The umbories are central or slightly posterior. The 

dentition in the right valve consists of 2 cardinals (the

anterior of which is slightly the stronger), and feebly 

developed lateral grooves. In the left valve the anterior cardinal is fairly strong, ^but the posterior is 

almost obsolete; there are no distinct laterals, although 

the dorsal margins are somewhat modified. The pallial sinus is deep and broad and evenly rounded.

The species is rare in Virginia but quite abundant 

in the post-Chesapeake formations of North Carolina. 

Mansfield reports a few young or fragmentary specimens from the Cancellaria zone of the Choctawhatchee 

formation.

Distribution: Virginia: Miocene, Yorktown formation, 1% 

miles northeast of Suffolk and 1 mile northeast of Suffolk, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, Tar Ferry 

on Wiccacon Creek (opposite Harrellsville) and Mounf Pleasant 

Landing, Hertford County; Colerain Landing and % to % 

mile above Edenhouse Point, Bertie County; 2% miles northwest of Williamston (on Joseph Cherry's farm), Martin County; 

3 miles southwest of Frog Level (on J. A. Noble's branch), 8 

to 9 miles southeast of Greenville, and 9 to 10 miles south 

of Greenville, Pitt County; 1 mile west of Wilson, Wilson 

County; 1 mile north of Castoria and 1 mile east of Lizzie 

(on the farm of T. N. Lassiter), Greene County; Rock Landing, Craven County. Duplin marl, drainage ditch just east of 

railroad 1% miles north of Magnolia, Duplin County; 2 miles 

below Lumberton, 4 to 5 miles below Lumberton, and 1% miles 

northeast of Fairmont, Robeson County. Pliocene, Waccamaw 

formation, Walkers Bluff, Bladen County; Lake Waccamaw, 

Cronly (% mile east of the factories), and Neills Eddy Landing 

(3 miles north of Cronly), Columbus County.

Outside distribution: Miocene, Duplin marl, Darlington 

County, S. C. Choctawhatchee formation, northern Florida. 

Pliocene, Waccamaw formation, Tillys Lake, Horry County, 

S. C. Caloosahatchee marl, Caloosahatchee River, Fla. Croatan 

sand, Slocums Creek and Mallisons, Craven County, N. C. 

Pleistocene, Dismal Swamp canal between posts 15 and 16, 

Virginia; Simmons Bluff, S. C.; Kissimmee well (at a depth of 

96 feet), Osceola County, Fla. Recent, Connecticut to the 

Gulf of Mexico in 13 to 233 fathoms; occurs in both shallow 

and deep water off Hatteras, elsewhere in shallow water only.

Abra aequalis deltoidea Gardner, n. subsp.

Plate 17, figures 25, 26

Shell convex, triangular; the three sides subequal, 

suggesting the Greek delta; truncate posteriorly, subtruncate anteriorly, evenly rounded toward the ventral 

margin, which is straight or slightly arched. Sculpture limited to incrementals as in the typical Abra 

aj&qualis of Say. Hinge normal in the number and disposition of the teeth but with the laterals of the right 

valve more strongly developed. '

Dimensions of cotypes: Eight valve, height 11.2 millimeters, width 11.4 millimeters, convexity 3.0 millimeters; left valve, height 11.1 millimeters, width 11.9 

millimeters, convexity 3.2 millimeters.

Cotypes, a right and a left valve of different individuals : U. S. Nat. Mus. 325586.

Type locality: Two miles below Lumberton, Robeson 

County, N. C. Duplin marl.
PART 1. PELECYPODA 105

The extremes of the subspecies seem quite distinct 

from Abra aequalis s. s., but the connecting series determines the true relation. A. cequalis dettoidea is 

characterized by the approximately equilateral outline 

and relatively strong dentition, which is doubtless the 

corollary of the heavier valves. The subspecies is best 

developed in the Duplin marl of Robeson County in 

the vicinity of Lumberton, though it is known also from 

the Waccamaw.

Distribution: North Carolina: Miocene, Yorktown formation, 

1 mile west of Wilson, Wilson County. Duplin marl, 2 miles 

below Lumberton and 4 to 5 miles below Lumberton, Robeson 

County. Pliocene, Waccamaw formation, Neills Eddy Landing, 

Columbus County.

Family DONACIDAE Deshayes 

Genus DONAX (Linnaeus) Lamarck

1758. Donax Linnaeus, Systema naturae, 10th ed., p. 682.

1799. Donax Lamarck, Prodrome d'une nouvelle classification

des coquilles: Soc. histoire nat. Paris Mem., p. 85. 

1847. Donax Gray, Zool. Soc. London Proc., pt. 15, p. 187.

Type by subsequent designation (Schmidt, C. F., Versuch 

iiber die beste Einricht, etc., pp. 55, 176, Gotha, 1818) : Donax 

rugosa Linnaeus. Recent in the West Indies.

Shell rather solid, moderately inflated, of varying 

dimensions, elongate-cuneate to trigonal to subcylindrical in outline. Umbones subcentral to posterior, 

opisthogyrate. Sculpture finely radial, often subcutaneous, sometimes punctate. Ligament both external 

and internal; external ligament short, heavy, inset; 

the resilium seated on short, usually excavated nymphs. 

Dentition rather rude; normally two cardinals in each 

valve, one of them commonly bifid; laterals varying 

widely in strength and relative position within the 

genus. Pallial sinus deep, partly confluent ventrally 

with the pallial line. Inner margins serrate.

The genus is remarkably uniform and well characterized by its solid, rather pronounced cuneate and 

flexuous valves, opisthogyrate and usually posterior 

umbones, and serrated inner margins. The earliest 

known occurrence of the form in American waters is 

in the Oligocene. The approximately 100 living species 

inhabit the sandy beaches of warm and tropical seas. 

They are lovely little bivalves, ornamented with varicolored rays on a dull gray or dun background. The 

"pampalone shells," as they are called along the Florida 

coast, where they are particularly abundant, are used 

to a considerable extent for food.

Donax emmonsi Dall

Plate 23, figure 5

1858. Donax Emmons, North Carolina Geol. Survey Kept., p. 298,

fig. 227 (cited by error as 226). 

1863. Donax Emmons. Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 574. 

1892. Donax emmonsi Dall, Nautilus, vol. 5, p. 126.

1898. Donax emmonsi Dall, Wagner Free Inst. Sci. Trans., vol.

3, pt. 4, pi. 28, fig. 16. 

1900. Donax emmonsi Dall, idem, vol. 3, pt. '5, p. 967.

Shell triangular, rather abruptly truncate behind, and traversed by a ridge from the umbo to the base; surface marked by 

obscure radiating lines; base crenulated. This small shell 

differs from the variabilis in its proportion; it is more triangular and is not produced so much in front.—Emmons, 1858.

This species is more triangular than any of the recent forms 

of the coast, faintly radially striate, ventrally somewhat flexuous, and with a sharply serrate margin. The teeth are normal 

and strong, especially the sockets for the laterals. Longitude 

10 [10.2], altitude 7 [6.7], diameter 4 millimeters.—-Dall, 1900.

Holotype, a right valve: U. S. Nat. Mus. 108447.

Type locality: Cape Fear River, near Cronly, N. C. 

Waccamaw formation.

It is strange that, though Emmons described and 

figured this species, he suggested no name by which it 

should be called.

Donax emmonsi Dall is separated from D. fossor Say 

by the relatively higher outline, the more ventricose 

valves,' the longer, more oblique, posterior dorsal 

margin, and the anterostral depression with the resulting contraction of the ventral margin. The species, 

exclusive of varietal forms, is rare and rather limited 

in distribution.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1% miles south of Reids Ferry, Nansemond 

County.

North Carolina: Miocene, Yorktown formation, Dogwood 

Landing, Hertford County; 2% miles northwest of Williamston 

(on the farm of Joseph Cherry), Martin County; 9 to 10 miles 

south of Greenville, Pitt County. Duplin marl, Natural Well, 

Duplin County; 4 to 5 miles below Lumberton, Fairmont, 1% 

miles northeast of Fairmont, and 4 miles -northeast of Fairmont, Robeson County. Pliocene, Waccamaw formation, 4 miles 

south of Elizabethtown (on Hammond Creek) and at Walkers 

Bluff, Bladen County; Neills Eddy Landing on the Cape Fear 

River (3 miles north of Cronly), Columbus County.

Donax emmonsi preaequilibrata Gardner, n. subsp. 

Plate 23, figures 3, 4

Valves tumid, elongate-trigonal, rostrate posteriorly, 

depressed in front of the rostrum; umbones posterior 

to subcentral; anterior dorsal margin oblique, posterior 

oblique or slightly hunched; base line feebly sinuated 

by the anterostral depression; basal serration sharp; 

hinge characters normal, varying somewhat with the 

outline of the valves.

The subspecies includes a series of forms gradational 

between the inequilateral, cuneate, rather strongly rostrate, and sinuous Donax emmonsi Dall s.s. and the 

more nearly equilateral and elongated D. aequilibrata 

Dall, in which the posterior carination is feeble and 

ill defined and the ventral margin almost, or altogether, 

straight.

D. emmonsi preaequilibrata is mostly limited to the 

Duplin marl of Robeson County. Its development in 

the environs of Lumberton and Fairmont suggests the
106 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

immediate vicinity as the site of the evolution of the 

Pliocene D. aequilibrata from the earlier D. ertvtnonsi. 

One rarely finds a connecting series so complete between extremes so widely separated.

Dimensions of holotype: Height 8.0 millimeters, 

width 14.4 millimeters, diameter of double valves 6.5 

millimeters.

Holotype (double valves) : U. S. Nat. Mus. 325590.

Type locality: 2 miles below Lumberton, Robeson 

County, N. C. Duplin marl.

Distribution: Virginia: Miocene, Yorktown formation, 1% 

miles north of Suffolk, Nansemond County.

North Carolina : Miocene, Yorktown formation, Rock Landing, 

Craven County. Duplin marl, Lumberton, 2 miles below Lumberton, 4 to 5 miles below Lumberton, and 4 miles northeast 

of Fairmont, Robeson County. Pliocene, Waccamaw formation, 

Walkers Bluff, Bladen County; Cronly, Columbus County.

Don ax aequilibrata Dall

Plate 17, figure 29

1892. Donax aequilibrata Dall, Nautilus, vol. 5, p. 126.

1898. Donax aequilibrata, Dall, Wagner Free Inst Sci. Trans.,

vol. 3, pt. 4, pi. 28, fig. 17. 

1900. Donax aequilibrata Dall, idem, vol. 3, pt. 5, p. 968.

Shell longer in proportion to its height than in any of our 

Recent species, rounded in front, the posterior end rostrate and 

pointed; truncated area impressed, its borders not carinated 

and ill defined, rostrum faintly grooved, the rest of the shell 

polished, with obsolete, impressed lines; inner margin denticulate; hinge teeth well developed, laterals strong and near the 

cardinals; pallial sinus rounded and extending a little in front 

of the beaks; the latter are well defined, not prominent, and 

nearly central. Longitude of shell 17 [17.9], altitude 8.9 [8.5], 

diameter 6 millimeters.—Dall, 1892.

Holotype, a right valve: U. S. Nat. Mus. 108450. 

Type locality: Mrs. Guion's marl bed, Cape Fear 

River, Columbus County, N. C. Waccamaw formation.

Distribution: North Carolina: Pliocene, Waccamaw formation, Mrs. Guion's marl pit and Neills Eddy Landing, Columbus 

County.

Donax chuckatuckensis Gardner, n. sp.

Plate 23, figure 6, 7

Shell small, remarkably compressed, cuneate. Umbones acute, flattened, opisthogyrate, placed about twothirds of the way back toward the posterior extremity. 

Anterior dorsal margin produced and oblique; posterior short and slightly rounded near the ventral 

margin. Posterior keel rounded off. Base line feebly 

arcuate, finely serrate within. Surface highly polished 

with a mircroscopic, subsurficial, radial lineation; hinge 

armature compact. Two- strong diverging cardinals in 

the left valve, separated by a subumbonal, triangular 

pit; on either side of the cardinals is a less prominent 

lateral, the posterior the stronger. Pallial sinus deep, 

indistinct.

Dimensions of holotype: Height 3.6 millimeters, 

width 5.2 millimeters, convexity 1.0 millimeter.

Holotype, a left valve: U. S. Nat. Mus. 325589.

Type locality: A quarter of a mile north of Chuckatuck, Nansemond County, Va. Yorktown formation.

Although the species is described from a single left 

valve, there should be no doubt about its determination, 

as it is well characterized by the compressed shell; by 

the sharp, flattened, almost subterminal umbones; by 

the absence of an acute posterior keel; the anterior 

truncation extending almost to the ventral margin; 

and by the smooth, highly polished external surface. 

Donax chuckatuckensis is perhaps most nearly related 

to D. fossor Say. The want of a sharp rostrum and 

the degree of truncation of the anterior margin will, 

however, preclude any confusion of the two forms.

Distribution: Virginia: Miocene, Yorktown formation, a 

quarter of a mile north of Chuckatuck, Nansemond County.

Donax fossor Say

Plate 23, figures 1, 2, 10, 11

1822. Donax fossor Say, Acad. Nat. Sci. Philadelphia Jour., 1st

ser., vol. 2, p. 306. 

1849. Donax protracta Conrad, idem, 2d ser., vol. 1, p. 208, pi.

39, fig. 8. (Senile stage.) 

1856. Donax variabilfe Tuomey and Holmes (not Say), Pleiocene fossils of South Carolina, p. 95, pi. 23, fig. 6. 

1863. Donax variabilis Tuomey and Holmes?. Conrad, Acad,

Nat. Sci. Philadelphia Proc. for 1862, p. 573. 

1873. Donax fossor Say. Tryon, American marine conchology,

p. 153, pi. 27, figs. 376, 377. 

1900. Donax fossor Say. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p. 967. 

1932. Donax fossor Say. Mansfield, Florida Geol. Survey Bull.

8, p. 151, pi. 31, figs. 6, 7.

Shell subtriangular; anterior margin short and rounded; 

posterior hinge slope rectilinear; base very slightly prominent 

beyond a regular curve at the middle; valves longitudinally 

striated with numerous, equal, parallel, regular impressed lines, 

not visible to the unassisted eye, and obsolete on the posterior 

margin; basal edge within crenate; color pale livid, with two 

longitudinal whitish rays before the middle, both within and 

without. Breadth from half an inch to three-fifths. Inhabits 

the coasts of New Jersey and Maryland.—Say, 1822.

The figured specimens (U. S. Nat. Mus. 325587) are 

from the Waccamaw formation 4 miles south of Elizabethtown, N. C. The right valve measures 3.3 millimeters in height and 5.0 millimeters in width; the left 

valve of another indiivdual measures 4.9 millimeters 

in height and 9.0 millimeters in width.

Say, in his description, has confused the anterior and 

posterior portions of the shell. The species is characterized by the posterior umbones; the rounded posterior margin, the long, only slightly oblique, anterior 

dorsal margin; and the straight base line. The form 

is much less conspicuously cuneate than Donax einmonsi Dall, the umbones are set farther back, the posterior dorsal margin is rounded instead of angular,
PART 1. PELECYPODA 107

and the prerostral area is not depressed sufficiently tosinuate the base.

The Kecent representatives range from the West 

Indies north to New Jersey, the only east coast species 

of Donax to venture into the temperate seas.

Mansfield reports eight valves from one locality in 

the Cancellaria zone of the Choctawllatchee formation, 

which "appear closely related to if not the same as the 

Recent species Donax fossor Say."

D. fossor is strikingly similar in outline and ornamentation to Z>. transversa Deshayes, the type of Paradonase from the Miocene of southern France, and to D. 

(Paradonax) aldrichi Gardner from the Oak Grove; 

but Paradonax -has no trace of an isolated anterior 

lateral such as that developed in D. fossor Say.

Distribution: North Carolina: Miocene, Yorktown formation, 

% to % mile above Edenhouse Point, Craven County. Duplin 

marl, 1% miles north of Magnolia, Duplin County; 4 miles 

northeast of Fairmont, Robeson County. Pliocene, Waccamaw 

formation, 4 miles south of Elizabeth town (on Hammond Creek) 

and Walkers Bluff (on the Cape Fear River), Bladen County; 

Lake Waccamaw and Neills Eddy Landing (3 miles north of 

Cronly), Columbus County.

Outside distribution: Miocene, Duplin marl, Sumter district, 

S. C. Choctawhatchee formation, northern Florida. Pliocene, 

Waccamaw formation, Tillys Lake, Horry County, and Goose 

Creek, Berkeley County, S. C. Caloosahatchee marl, Caloosahatchee River, Fla. Croatan sand, Slocums Creek, Craven 

County, N. C. Pleistocene, Simmons Bluff, S. C.; Rose Bluff on 

the St. Marys River, Nassau County, Fla. Recent, Far Rockaway, Long Island, to the Florida Keys in less than 50 fathoms.

Family GAfellDAE 

Genus TAGEIUS Gray

1817. Siliquaria Schumacher, Essai d'un nouveau syst£me des 

habitations des vers testaces, p. 129. Not Siliquaria 

Bruguiere, 1789, Encyclopedie me"thodique (Vers), vol. 

1, p. xv.

1847. Tagelus Gray, Zool. Soc. London Proc., pt. 15, p. 189.

Type by original designation: Solen guineensis [guinensis'] 

Chemnitz=So1en gibbus Spengler. Fossil from the late Miocene 

to Recent from Cape Cod to Brazil and on the west coast of 

Africa.

The shell is elliptical to subquadrate, about three 

times as wide as it is high, feebly inflated, warped by 

an obscure medial constriction and a broadly rounded 

posterior keel, and gaping behind. The umbones are 

medial or slightly posterior and without tips. The 

shell is constricted slightly behind the umbones, but 

both the posterior and the anterior dorsal margins 

are rudely parallel to the base and the lateral margins 

slightly oblique to the base but roughly parallel to 

each other. The only sculpture developed is incremental in character. The ligament is attached to short 

but heavy nymphs, and two slender pedunculate cardinals spring from the slightly thickened area beneath 

the umbones that passes for a hinge plate. The posterior muscle scar is rounded—the anterior ragged and

elongated parallel to the dorsal margin. The pallial 

sinus is deep and its axis nearly horizontal.

Tagelus gibbus (Spengler) Dall

Plate 22, figures 1-4

1685. Chama angustior, etc., Lister, Historiae conchyliorum, 

fig. 265.

1794. Solen gibbus Spengler, Skr. Naturhistorie-Selsk. Kiobeiihavn, vol. 3, pt. 2, p. 104.

1795. Solen guineensis Chemnitz, Conchylien cabinet, vol. 11, p.

202, pi. 198, fig. 1937. 

1818. Solen caribo<eus Lamarck, Histoire naturelle des animaux

sans vertebres, vol. 5, p. 454. 

1827. Solecurtus cariboeus Lamarck. Blainville, Dictionaire des

sciences naturelles, vol. 49, p. 420.

1831. Solecurtus cariboeus Blainville. Conrad, American marine conchology, p. 22, pi. 4, fig. 3. 

1841. Solecurtus caribaeus Lamarck. Gould, Invertebrata of

Massachusetts, p. 30. 

1843. Solecurtus cariboeus Lamarck. Mighels, Boston Jour.

Nat. History, vol. 4, p. 312. 

1846. Gultellus cariboeus Conrad, Am. Jour. Sci., 2d ser., vol. 1,

p. 404. Not of Conrad, 1845, Fossils of the medial

Tertiary of the United States, p. 75, pi. 43, fig. 1.

=Tagelus gibbus carolinensis (Conrad). 

1858. P. [anopaea.] cariboeus Emmons, North Carolina Geol.

Survey Rept, p. 299, fig. 228a. 

1858. Silliquaria ccuriboea, Blainville. Holmes, Post-Pleiocene

fossils of South Carolina, p. 54, pi. 8, fig. 14. 

1863. Siliquaria carolinensis Conrad (part), Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 571. 

1900. Tagelus gibbus Spengler. Dall, Wagner Free Inst. Trans.,

vol. 3, pt. 5, p. 983.

1906. Tagelus gibbus (Spengler). Clark, Maryland Geol. Sur-

. vey, Pliocene and Pleistocene, p. 200, pi. 57, figs. 1-4.

1906. Solecurtus (Tagelus) gibbus Spengler. Bose, Inst. geol.

Mexico Bol. 22, p. 83, lam. 12, fig. 2.

Solen gibbus, testa lineari, valvula antice et postice gibboslineari obliqua.—Spengler, 1794.

Type locality not known.

Valves thin, gaping, inequilateral, transversely elliptical. Umbones flattened, slightly posterior. Postumbonal portion of shell narrower than preumbonal, by 

reason of the abrupt though slight contraction behind 

the beaks. Both anterior and posterior dorsal margins 

approximately parallel to the base. Anterior and posterior lateral margin obtusely truncated, approximately 

parallel to each other. Base line feebly contracted by 

a broad but very shallow medial depression of the 

valves. Posterior area faintly delimited by an obscure keel that extends from the umbone to the posterior ventral margin. Surface sculptured with irregular concentric growth lines. Ligament external, 

sliQrt, strong, attached to unusually stout nymphs. 

Cardinals proximate, long, slender, recurved at the 

pointed tips, 2 in each valve. Anterior adductor 

muscle impression elongated, parallel to the dorsal 

margin, tapering behind; posterior impression semielliptical. Pallial line distant from the ventral margin. 

Pallial sinus deep, extending beyond the median line 

of the shell.
108 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA ^ND NORTH CAROLINA

The type of this genus is rather widely distributed 

in the late Miocene and Pliocene of the east co.ast. It 

is quite common in the Miocene cliffs below Yorktown, 

and in the waters at the base of the cliffs the Recent 

representatives are flourishing.

The figured specimens are from Wailes Bluff near 

Cornfield Harbor, St. Marys County, Md. They are 

taken from Clark, 1906, who reproduced them natural 

size.

The Recent species, which may be estuarine or marine, 

are separated from certain members of the Solenidae, 

which they closely resemble, by the hinge characters 

and the very much longer siphons. The genus has 

been recognized in rocks as old as the Cretaceous.

Though the number of species referable to Tagelus 

is very small, yet this genus includes two species of 

remarkable longevity—one the type of Tagelus s. s., 

the other of the subgenus Mesopleura. T. gibbus 

(Spengler) has not been found in strata older than the 

Yorktown formation, but the ancestors of T. divisus 

(Spengler) were flourishing certainly as early as 

Chipola time.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County.

North Carolina: Pliocene, Waccamaw formation, Walkers 

Bluff, Bladen County; Neills Eddy Landing, Columbus County.

Outside distributions: Miocene, Santa Maria Tetetla, Vera 

Cruz, Mexico. Pliocene, Waccamaw formation, Todds Ferry, 

Waccamaw River, Horry County, S. C. Caloosahatcb.ee marl, 

Caloosahatchee River, Fla. Pleistocene, New Bedford, Mass. 

(Dall) ; Wailes Bluff and Langleys Bluff, St. Marys County, Md.; 

Charleston, Simmons Bluff, and Abbapoola, S. C. Recent, 

Cape Cod to Rio Grande del Sul, east to (?) Europe and 

(?) Africa, and possibly on the west coast of North America; 

restricted largely to 5 fathoms and less on mud or sandy mud 

bottom.

Tagelus gibbus carolinensis (Conrad) Ball

Plate 22, figure 5

1845. Cultellus oariboeus Conrad (part), Fossils of the medial

Tertiary of the United States, p. 75, pi. 43, fig. 1. Not

Solen cariboeus Lamarck, 1818. 

3863. Siliquaria carolinensis Conrad (part), Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 571. 

1900. Tagelus glbbm var. carolinensis Conrad. Dall, Wagner

Free Inst. Sci. Trans., vol. 3, pt. 5, p. 983.

This form differs from the typical gibbus in being somewhat 

shorter and stouter and with a shorter pallia! sinus. The differences are, however, little greater than appear between specimens of the recent shell from different localities.—Dall, 1900.

Dimensions of holotype: Height, 23 millimeters, 

width 69 millimeters.

Holotype: U. S. Nat. Mus. 145293.

Type locality: Wilmington, New Hanover County, 

N. C. Waccamaw formation.

Distribution: North Carolina: Pliocene, Waccamaw formation, Wilmington, New Hanover County.

Superfamily SOLEWACEA

Family SOLENIDAE 

Genus SOLEN Linnaeus

1758. Solen Linnaeus, Systema naturae, 10th ed., p. 672.

1777. Solen Scopoli, Introductio ad historian! naturalem sistens 

genera lapidum, plantarum et animalium hacterius 

detecta caracteribus essentialibus donata in tribus 

divisa subinde ad legas naturae, Prague. (No type 

selected.)

1799. Solen Lamarck, Prodrome d'une nouvelle classification 

des coquilles: Soc. histoire nat. Paris Mem., p. 83.

1930. Solen, Linnaeus, Stewart, Aead. Nat. Sci. Philadelphia 

Special Pub. 3, p. 289.

Type by subsequent designation (Schumacher, Essai d'un 

nouveau systeme des habitations des vers testaces, pp. 42, 124, 

1817) : Solen vagina, Linnaeus. East Indies?

Shell long, narrow, generally straight, scabbardshaped. Umbones anterior, subterminal. External 

surface polished, smooth, or feebly sculptured. Ligament external, elongated. Hinge armature limited to 

a single cardinal in each valve. Anterior adductor 

muscle impression very long and narrow, near and 

parallel to the dorsal margin; posterior impression 

semielliptical. Pallial line distinct, sinus shallow.

Ensis resembles Solen externally, but internally it 

differs in the possession of 2 vertical cardinals in the 

left valve instead of a single one, as in Solen. , The Recent species Lumber about 50 and are worldwide in distribution. The majority are littoral. At 

the approach of danger they burrow rapidly downward 

by means of the alternate extension and contraction 

of the foot, which serves first as a blade to cut, through 

the sand and then as an anchor by which they may 

hold until the valves can be pulled down.

The genus has been recognized as edible since the 

days of Aristotle, and the clam fishers along the French 

coasts use the same type of tackle today as that 

employed by ancient Greek fishermen.

Solen viridis Say

Plate 23, figure 40

1822. Solen viridis Say, Acad. Nat. Sci. Philadelphia Jour., 1st

ser., vol. 2, p. 316. 

1831. Solen viridis Say. Conrad, American marine conchology,

p. 28, pi. 5, fig. 2. 

1900. Solen viridis Say. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p. 952.

Shell fragile, elongated, compressed, a little narrowed before, 

slightly wrinkled concentrically, the wrinkles regularly rounded 

toward the extremity; hinge margin nearly rectilinear; basal 

margin a little arquated; anterior tip rounded; posterior tip 

obliquely truncated, a little reflected and rounded near the base; 

hinge terminal; teeth one in each valve, each having a flattened 

vertical surface, which turns upon that of the opposite tooth; 

epidermis pale green.

Length %o of an inch, nearly; breadth 2%0 inches.
PART 1. PELECYPODA 109

Inhabits the southern coast.

Cabinet of the Academy and Philadelphia Museum.—Say,

1822.

A recent shell (U. S. Nat. Mus. 153356) from Smiths 

Island, Va., has been figured. The height is 7.5 millimeters, the width 35.5 millimeters.

Fragments of this species, showing the diagnostic 

terminal cardinal and the narrow, elongated, adductor 

muscle impression, have been found at a single locality 

in the Waccamaw formation. Hitherto the form has 

been known only from the Pleistocene of Simmons 

Bluff and from the Recent east coast faunas from 

Rhode Island to Georgia.

The more anterior vertical cardinal, the absence of 

the horizontal cardinal, and the position of the anterior 

adductor impression—parallel rather than oblique to 

the dorsal margin—will serve to separate this species 

from the coexistent Ensis, which it closely resembles in 

general aspect.

Distribution: North Carolina: Pliocene, Waccamaw formation, Walkers Bluff on the Cape Fear River, Bladen County.

Outside distribution: Pleistocene, Simmons Bluff, S. C. Recent, Rhode Island to Sarasota Bay, west Florida, and west to 

Texas in less than 50 fathoms.

Superfamily MACTRACEA 

Family MACTRIDAE

1917. Lamy, Revision des Mactridae vivants du Museum 

d'Histoire Naturelle de Paris, Jour, conchyliologie, vol. 

63, pp. 173-275.

1918. Lamy, idem, pp. 291-411.

Genus MACTRA Linnaeus

1766. Mactra Linnaeus, Systema naturae, 12th ed., p. 1125. 

1799. Mactra, Lamarck, Prodrome d'une nouvelle classification

des coquilles: Soc. histoire nat. Paris Mem., p. 85. 

1898. Mactra Dall, Wagner Free Inst. Sc}. Trans., vol. 3, pt. 4,

p. 874.

Type by subsequent designation (Anton, Verzeichniss der 

Conchylien, p. 2, 1839) : Mactra stultorum Linnaeus. Recent 

on west European shores from Norway southward to the Mediterranean and possibly to the Red Sea. Fossil in the Crag.

Within the family the best diagnostic of the genus 

is the small shelly plate that separates the area of 

attachment of the internal ligament from that of the 

marginal external ligament. The plate is so thin and 

so short that it is frequently lost in the fossil forms, 

and traces of its former existence are hard to find.

Labiosa, a large thin shell reinforced by a concentric 

rippling, resembles Mactra in that the marginal and 

internal ligaments are separated by a thin lamella. 

The laterals of Labiosa, however, are rudimentary. 

The hinge of L. (Raeta) alta (Conrad), from the Miocene of North Carolina, is figured (pi. 18, fig. 6) for 

comparison with Mactra.

Subgenus MACTROTOMA Dall

1894. Mactrotoma Dall, Nautilus, vol. 8, p. 2(5. 

1898. Mactrotoma Dall, Wagner Free Inst. Sci. Trans., vol. 3, 

•pt. 4, p. 876.

Type by original designation: Mactra fragilis Gfmelin. Recent 

on the east coast from Hatteras to Brazil.

Anterior left lateral tooth bidentate, right ventral tooth 

tridentate.—Dall, 1894.

Shell subequilateral, elongate; with a thin, silky epidermis, 

posterior dorsal areas bordered by an impressed fasciole, over 

which the epidermis is darker colored and differently wrinkled; 

beaks adjacent; pallial sinus large; valves convex, gaping 

markedly; ligament lanceolate; chondrophore large, shallow, 

apically roofed; anterior laminae issuing from the dorsal sinus; 

cardinals prominent, thin, their posterior arms projecting over 

the chondrophore; each anterior arm attended by a high accessory lamella in nearly the same plane, closely appressed in the 

right valve to the ventral lamina and in the left valve to the 

anterior lateral, so that, to a cursory inspection, the lamina 

appears tridentate and the tooth bidentate.—Dall, 1898.

Mactra (Mactrotoma) fragilis Gmelin

Plate 18, figures 9-11, 13

1790. Mactra fragilis Gmelin, Systema naturae, vol. I, pt. 6.

p. 3261. 

1898. Mactra (Mactrotoma) fragilis Gmelin. Dall, Wagner

Free Inst.. Sci. Trans., vol. 3, pt. 4, p. 894, pi. 27,

figs. 1, 4, 8, 18.

M. testa ovata tenui laevi pellucida planiuscula, vulva transversim striata rugosaque, Chem. Conch. 6, t. 24, f. 235.— 

Gmelin, 1790.

This species, the type of the subgenus, is widely distributed 

and represented in eastern seas by very similar though generally smaller species. It was erroneousty referred to the 

Nicobar Islands by Chemnitz, but his figure enables us to 

correctly identify his species with the American shell.—Dall, 

1898.

Mactra fragilis s.s. has not been reported from beds 

older than the Caloosahatchee. The Recent species 

ranges from Cape Hatteras, N.. C., to Rio de Janeiro. 

It is cited for comparison with a possibly ancestral 

subspecies and Dall's excellent figures of the hinge 

plates have been reproduced.

Mactra (Mactrotoma) fragilis precursor Gardner, n. subsp.

Plate 18, figure 14

Shell oblong, oval, compressed; dorsal margins gently 

sloping, anterior lateral margin rounded, posterior 

obliquely truncated. Base line arcuate. Posterior 

area clearly differentiated, sculptured with 2 narrow 

acute ribs, of which the dorsal is the stronger; obscure 

medial rib also present. Surface sculpture of very fine, 

irregular, discontinuous concentric striae, which are 

more numerous on the anterior portion of the shell and 

terminate abruptly at the posterior keel. Hinge and 

pallial characters as in M. fragilis Gmelin, the type 

of the genus.

401033—45
110 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Dimensions of holotype: Height 79.0 millimeters, 

width 121.0 millimeters, convexity 20.0 millimeters.

Holotype, a left valve: U. S. Nat. Mus. 325593.

Type locality: Neills Eddy Landing, Columbus 

County, N. C. Waccamaw formation.

A complete series might prove the distinguishing 

characters of this Mactra to be only individual variations from-^f. fragilis. As the species has never before been reported from so early a horizon, it seems 

batter to regard the relatively lower, more oblong outline and the more gently sloping dorsal margins oi 

this single, finely preserved, left valve as subspecific 

rather than individual differences.

M. (Mactrotoma] profragilis Gardner, from the Oak 

Grove sand of Florida, is a smaller shell with more 

pointed umboiies and a more decided concentric striation. The three forms in question are, however, closely 

related.

Distribution: North Carolina: Pliocene, Waccamaw formation, Neills Eddy Landing, Columbus County.

Genus SPISUIA Gray

1837. Spisula Gray, Mag. Nat. History, new ser., vol. 1, p. 372. 

1898. Spisula, Gray. Dall, Wagner Free Inst. Sci. Trans., vol. 3,

pt. 4, p. 878. 

1918. Spisula, Gray. Lamy, Jour, conchyliologie, vol. 63, p. 291.

Type by subsequent designation (Gray, Zool. Soc. London 

Proc., pt. 15, p. 185, 1817) ; Mactra, solida Linnaeus. Recent 

on the west coast of Europe. Fossil in the Crag.

Shell often large and rather heavy, moderately inflated, subequilateral, ovate-trigonal in outline, slightly 

produced and obscurely ro&trate posteriorly. Umbones 

prominent, subcentral. Surface smooth or incrementally scultpured. Ligament inset, not cut off from the 

resilium by a shelly ridge. Hinge armature strong. 

Right anterior and posterior cardinals coalescent under 

the mnbones, the anterior arm near the dorsal margin, 

the posterior bordering the chondophore and partly 

separating it from the socket in which the small, inverted V-shaped cardinal of the left valve is lodged. 

Strong lateral teeth, developed within the dorsal margins of the left valve, received in the double sockets 

of the right; teeth and sockets both transversely striated in most of the groups. Muscle scars large and 

sunken in the heavier shells. Pallial sinus distinct, 

short, broadly U-shaped, nearly horizontal.

The absence of a shelly lamina between the chondrophore and the ligament separates Spisula from Mactra. 

Furthermore, the laterals of Mactra are smooth or 

finely granular, but those of Spisula are as a rule 

transversely striated.

The genus extends well back into the Cretaceous, and, 

though not abundantly represented in Recent seas, it 

is of almost universal occurrence.

For the half dozen Miocene Spisulas considered in 

this report, the superspecific groupings are far from

satisfactory. Three of the species and one subspecies 

are small, heavy forms allied to similar Miocene species 

and possibly sufficiently removed from the subgenotype 

to receive a new sectional name. The other two Miocene forms that are referred to Mactromeris" are relatively large and thin, and seemingly they differ more 

from the type of Hemimactra than Hemimactra differs 

from Spisula.

Subgenus HEMIMACTRA Swainson

1840. Hemimactra Swainson, Treatise on malacology, 

p. 369.

Type by monotypy: Mactra, gigantea Lamarck= 

Mactra solidissima Chemnitz. Recent seas from Labrador to North Carolina.

Swainson, in his original description of Hemimactra 

cited a second species, "Hemimactra grandis Swainson, 

sp. nov.," but as his species was neither described nor 

figured the name seems to be nude.

Many of the large, transversely elongated^ and relatively thin species of Spisula are included under the 

subgenus Hemimactra.

Section HEMIMACTRA s. s.

Laterals grooved; cardinals compressed; anterior arm 

of right cardinal confluent with ventral lamina.

Spisula (Hemimactra) rappahannockensis Gardner, n. sp.

Plate 18, figure 2-4, 7

Shell elongate-trigonal. Umbones inflated, subcentral, prosogyrate at their tips. Anterior dorsal margin 

oblique, the lateral margin rounded. Posterior dorsal 

margin more steeply sloping than the anterior, the 

lateral extremity rounded or vaguely truncated. Base 

line straight or slightly sinuous towar,d the posterior 

margin. Surface smooth except for incrementals. 

Concrentric furrows often developed by weathering as 

in Spisula confragosa Conrad. Chondrophore obliquely triangular, cardinal teeth compressed. Laterals not very heavy, straight, transversely grooved, 

lateral furrows of right valve also grooved. Muscle 

impressions and pallial line distinct. Pallial sinus 

rounded, extending about two-thirds of the distance 

from the posterior margin to the medial line of the 

shell.

Dimensions: Holotype, height 21.0 millimeters, 

width 31.5 millimeters, convexity 7.3 millimeters; paratype, height 15.0 millimeters, width 23.0 millimeters, 

convexity 5.3 millimeters. Two other valves: Height 

19.2 and 20.4 millimeters, width 27.1 and 28.8 millimeters, convexity 6.8 and 6.5 millimeters.

Types: Holotype, a ris:ht valve, and left figured 

hinpre. TT. S. Nat. Mus. 325601; paratype, a left valve, 

U. S. Nat. Mus. 325600.
PART 1. PELECYPODA 111

Type locality: Holotype, and left hinge, 1 to 2 miles 

below Bowlers Wharf on the Kappahannock River, 

Essex County, Va. St. Marys formation.

Paratype, Union Mills, 2% miles south of Farnham, 

Richmond County, Va.

The young of S. rappahannockensis are higher and 

more triangular than the adults. There is, in many of 

the individuals, an ill-defined ridge extending from 

the umbo to the posterior end of the basal margin, a 

ridge that becomes obsolete in the adults. The new 

species is separated from /$. confragosa Conrad and S. 

sub par His Conrad by the more gibbous umbones, the 

more gently sloping dorsal margins, and the tendency 

toward a posterior truncation and sinuous base line.

The species is exceedingly abundant at certain localities along the Rappahannock River and the surrounding territory, notably near Bowlers Wharf and at 

Union Mill, 2% miles south of Farnham. The individuals developed at the latter locality exhibit a decidedly 

more elongated outline than do those along the river.

Distribution : Virginia: Miocene, St. Marys formation ?, Nomini*Cliffs, Westmoreland County. St. Marys formation; 2% 

miles south of Farnham, Richmond County; 1 to 2 miles below 

Bowlers Wharf, Essex County; Urbanna Bluff, Middlesex 

County.

Spisula (Hemimactra) modicella (Conrad) Meek

Plate 23, figures 8, 9, 18, 19

1833. Mactra modicella, Conrad, Am. Jour. Sci., 1st ser., vol. 23, 

p. 340.

1838. Mactra modicella, Conrad, Fossils of the medial Tertiary 

of the United States, p. 25, pi. 13, fig. 3.

1863. Hemimactra modicella, Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 572.

1898. Spisula modicella, Conrad. Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 4, p. 900.

Shell subtriangular, compressed; posterior side shortest and 

abrupt or truncated at the extremity; fosset a little oblique, 

triangular; lateral teeth strong. Length, three-fourths of an 

inch.

Locality, Yorktown, Va.—Conrad, 1833.

A small, heavy species, characterized by the flattened 

inequilateral valves, the produced anterior extremity, 

the strongly grooved laterals, the conspicuous muscle 

impressions and pallial line. The form seems to be 

peculiarly susceptible to weathering forces, for all the 

individuals have a very much worn and battered aspect. 

It varies quite widely in relative proportions—so 

widely, indeed, that it has been thought wise to give 

the higher forms subspecific rank.

Dimensions of figured specimens: Right valve, height 

11.2 millimeters, width 15.0 millimeters, convexity 3.9 

millimeters. Immature left valve, height 7.9 millimeters, width 11.7 millimeters, convexity 2.3 millimeters.

Figured specimens: U. S. Nat. Mus. 325598.

Locality of figured specimens: One mile northeast of

Suffolk, Nansemond County, Va. Yorktown formation.

These weather-beaten little forms are among the most 

abundant of the smaller bivalves in the vicinity of 

Yorktown.

Distribution: Virginia: Miocene, St. Marys formation, Union 

Mill, 2% miles south of Farnham, Richmond County. Yorktown formation, Yorktown, York County; % mile northeast 

of Smithfield, Isle of Wight County; % mile north of Chuckatuck, iy2 miles southeast of Reids Ferry, 1 mile northeast of 

Suffolk, 1 mile west of Suffolk, and % mile below the Suffolk 

waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, 6 miles below 

Greenville, 8 to 9 miles south of Greenville, and 9 to 10 miles 

south of Greenville, Pitt County.

Spisula (Hemimactra) modicella alta Gardner, n. subsp.

Plate 23, figures 16, 17

The subspecies resembles Spisula (Hemimactra) 

modicella s. s. except in the notably greater height; 

concomitant with this are the more oblique anterior 

and posterior dorsal margins. The general aspects of 

the normal and of the varietal forms are therefore 

quite dissimilar.

The subspecies is best developed % at Rock Landing, 

on the Neuse River. At this locality it is one of the 

most conspicuous of the smaller bivalves and occupies 

a position in the fauna similar to that of S. 'modicella s. s. in the Yorktown of Virginia.

Dimensions of holotype: Height 13.2 millimeters, 

width 18.0 millimeters, convexity 4.1 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325599. •

Type locality: Rock Landing, Craven County, N. C. 

Yorktown formation. S. (Hemimactra) modicella alta 

is a higher, cruder shell than S. (Hemimactra) craspedota, an abundant species in the Shoal River formation. 

It is much less elongated transversely than the St. 

Marys form, S. rappahannockensis.

Distribution: Virginia: Miocene, Yorktown, formation, 1% 

miles northeast of Smithfield, Isle of Wight County; ^4 mile 

north of Chuckatuck, Nansemond County.

North Carolina: Miocene, Yorktown formation, 3 miles south 

of Farmville, Pitt County; Colerain Landing, Bertie County; 

Rock Landing and 2 miles southwest of Maple Cypress, Craven 

County. Duplin marl, 4 miles northeast of Fairmont, Robeson 

County.

Spisula (Hemimactra) similis (Say) Gardner

Plate 22, figures 6, 7 

1822. Mactra similis Say, Acad. Nat. Sci. Philadelphia Jour.,

1st ser., vol. 2, p. 309. 

1856. Mactra, similis Say. Tuomey and Holmes, Pleiocene

^ fossils of South Carolina, p. 97, pi. 23, fig. 8, 

1856. Mactra, similis Say. Holmes, Post-Pleiocene fossils of 

South Carolina, p. 39, pi. 7, fig. 8.

Shell subtrigonate, smooth, or very slightly wrinkled, white 

on the disk or upon the umbones, and dirty light brownish 

colour on the margin; umbones nearly central; lateral teeth 

strongly and regularly crenated on the side next the recipient 

cavity.
112 MOLLUSCA FROM MIOCENE AND LOWER -PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Length l%o inches, nearly1 ; width 1% inches. 

Inhabits the coast of the United States. 

Cabinet of the Academy.—Say, 1822.

The young of this species are very close to adult 

Spisula subparUis of Conrad. In the former, however, 

the shell is sub-ovate and rounded posteriorly; in the 

latter, subtriangular and obliquely truncated posteriorly.

Distribution: North Carolina: Miocene, Duplin marl, 2 miles 

below Lumberton and 1% miles northeast of Fairmont, Robeson 

County. Pliocene, Waccamaw formation, Cronly, % mile east 

of the factories, Columbus County.

Outside distribution: Pliocene, Waccamaw formation, Nixons 

and Tilly Lake, Horry County, and Goose Creek, Berkeley 

County, S. C. Pleistocene, Simmons Bluff, Abbapoola, and St. 

Andrews, S. C.; Orient, Hillsborough County, Fla.; Kissimee 

well (at a depth of 96 feet), Osceola County, Fla. Recent, 

Massachusetts to Florida and the Gulf of Mexico.

Section MACTROMERIS Conrad

1868 (January). Mactromeris Conrad, Am. Jour. Conchology 

for 1867, vol. 3, app., p. 45.

Type by subsequent designation (Dall, Wagner Free Inst. Sci. 

Trane., vol. 3, pt. 4, p. 878, 1898) : Spi -ula ovalis Gould=Mactra 

polynyma Stimpson. Recent from Hudson Bay to Cape Ann, 

Mass.

The section is characterized by smooth or feebly 

granular laterals, noncompressed cardinals, and the 

isolation of the anterior arm of the right cardinal from 

the ventral lamina.

Spisula (Mactromeris) bowlerensis Gardner, n. sp.

Plate 18, figures 1, 5

Shell rather large, thin, moderately inflated, rudely 

trigonal, equivalve, inequilateral. Anterior end slightly 

excavated dorsally, rounded laterally. Posterior end 

gently sloping, very slightly arched dorsally, obscurely 

truncated laterally. Ventral margin straight medially, 

upturned before and behind. Anterior dorsal area 

slightly impressed, not clearly delimited. Posterior 

area including a smooth, somewhat depressed region 

next to the margins and in front of them, a narrow 

roughened wedge-shaped surface, the anterior boundary of which is marked by an irregular pitted line1 

extending from the umbo to the posterior ventral 

margin. Umbones rather low and inconspicuous, proximate, slightly prosogyrate. Surface irregularly furrowed with growth lines and with a peculiar reticulate 

wrinkling. Hinge armature strong and clean-cut. 

Chrqndrophore cuneate, expanding posteriorly. Anterior arm of right cardinal coalescent with ventral 

lamina. Inverted V-shaped cardinal of left valve compressed. Laterals short but prominent, their inner 

surfaces granular. Muscle impressions distinct but 

not conspicuous. Pallial sinus of equal breadth 

throughout its length, rounded in front, not ascending

appreciably, projected almost but not quite halfway 

to the anterior margin.

Dimensions of holotype: Height 53.0 millimeters, 

width 70.0 millimeters, diameter 28.0 millimeters.

Holotype, paired valves: U. S. Nat. Mus. 498201.

Type locality: iy2 - miles below Bowlers Wharf, 

Rappahannock River, Va. St. Marys formation.

Spisula (Mactromeris) bowlerensis is most nearly related to S. (M.) duplinensis Dall. It is readily separable from the latter, however, by the higher and 

somewhat less inflated valves; by the more inequilateral 

outline, which is consequent on the more pronounced 

excavation of the anterior dorsal slope of bowlerensis 

and its slightly convex posterior dorsal margin; by the 

less smooth and polished external surface; atid by the 

broader, nontapering pallial sinus. The new species is 

smaller and less inequilateral than S. delumbis Conrad, less strongly concave anteriorly, more gently sloping and less strongly angulated posteriorly, and with a 

deeper and less sharply ascending pallial sinus. /& 

valhosierr Gardner, from the Shoal River, is closely 

related, but the beaks and hinge plate of the older 

species are not so high and the posterior area is less 

clearly defined.

This interesting form, which seems to be intermediate 

between S. delumbis and S. duplinensis and yet distinct 

from both of them, is fairly abundant in the single 

area where it has been found—Bowlers Wharf, on 

the Rappahannock River.

Distribution: Virginia: Miocene, St. Marys formation, Bowlers 

Wharf and 1 to % miles below Bowlers Wharf, Essex County.

Spisula (Mactromeris) duplinensis Dall

Plate 22, figure 10

1898. Spisula, (Hemimactra) duplinensis Dall, Wagner Free 

Inst. Sci. Trans., vol. 3, pt. 4, p. 898, pi. 30, fig. 1.

Shell subovate, thin, moderately inflated; beaks subcentral, 

not prominent, adjacent; surface smooth except for incremental 

lines, which are most prominent toward the ends; the middle 

of the valve is more or le§s polished, anterior end somewhat 

shorter than the posterior, both moderately rounded; dorsal 

slope nearly equal on both sides of the beak; dorsal areas 

obscure, the posterior 'smoother and more impressed; hinge 

much as in S. marylandica, but the pit larger and with a more 

projecting ventral margin; pallial sinus reaching forward more 

than half the length of the shell, pointed in front; basal margin 

curved but not arcuate. Longitude 58, altitude 42, diameter 

22 millimeters.

This species at first sight looks very close to 8. marylandica 

but has a longer pallial sinus, less prominent beaks, more 

equal dorsal slopes, and less arcuate basal margin. The lateral 

laminae are finely granulated and not striated—which separates it at once from the similis group—and the proportions 

are quite different from those of the young $. polynyma Stimpson of the same size. It is probably the shell referred to 8. 

similis Say by Tuomey and Holmes 47 and Emmons. **.—Dall, 

1898.

47 Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 97, pi. 

23, fig. 8, 1850.

48 Emmons, B., North Carolina Geol. Survey Kept., p. 298,1858.
PART 1. PELECYPODA 113

Holotype, a right valve: U. S. Nat. Mus. 153T84.

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl. , Though the figure of Tuomey and Holmes is not 

conclusive, the finding of indubitable specimens of 

S. similis in the t)uplin of Robeson County makes the 

correctness of their determination plausible.

Distribution : North Carolina "Chesapeake Miocene of Duplin 

County, Willcox."

Genus MULINIA Gray

1837. Mulinia Gray, Mag. Nat. History, new ser., vol. 1, p. 375. 

1898. Mulinia Dall. Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, 

p. 880.

Type by subsequent designation (Herrmannsen, Indicis generum Malacozoorum, vol. 2, p. 61, July 1847) : Mactra later alis 

Say. Recent from New Brunswick to Texas and the West 

Indies. Late Tertiary and Pleistocene.

Shell with the ligament and resilium both enclosed in a single 

pit and invisible externally. Laterals subequal, moderately distant ; teeth normal ; valves closing almost hermetically ; pallial 

sinus short and small ; siphons short ; foot narrow, pointed.

Widely distributed in estuaries of the tropics and temperate 

seas over most of the world. The most conspicuous species are 

from South America. — Dall, 1898.

Mulinia congesta (Conrad) Dall

Plate 23, figures 12-15, 21-24

Mactra congesta Conrad, Am.- Jour. Sci., 1st ser., vol. 23,

p. 340. 

Mactra congesta Conrad, Fossils of the medial Tertiary

of the United States, p. 27, pi. 15, fig. 2. 

Mactra crassidens Conrad, Am. Jour. Sci., 1st ser., vol. 41,

p. 346, pi. 2, fig. 11. 

Mactra triquetra Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 1, p. 324. 

Mactra triquetra Conrad, Fossils of the medial Tertiary

of the United States, p. 69, pi. 39, fig. 3. 

Mactra crassidens Conrad, idem, p. 69, pi. 39, fig. 5. 

Mactra congesta Conrad. Tuomey and Holmes, Pleiocene

fossils of South Carolina, p. 98, pi. 23, fig. 10. 

Hemimactra congesta Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 572. 

Mulinia crassidens Conrad, idem, p. 573. 

Mulinia triquetra Conrad, idem, p. 573. 

Standella congesta Conrad, idem, p. 573. 

Mactra (Mulinial) lateralis "Say". Whitfield, U. S. Geol.

Survey Mon. 24, p. 82, pi. 15, figs. 1-3. Not Mactra

lateralis Say, 1821. 

Mulinia congesta Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 4, p. 900. 

Mulinia congesta (Conrad). Mansfield, Florida Geol.

Survey Bull. 8, p. 154, pi. 32, figs. 1, 2, 5, 6.

Shell triangular, convex, thick ; posterior side cuneate, beaks 

nearly central; lunule none; fosset small, circular, profound; 

lateral teeth thick. Length, 1 inch.

Locality: Suffolk, Va., where it is extremely abundant. A 

much smaller variety occurs at James River — generally shorter 

in proportion to the height, and with central beaks. Upper marine formation. — Conrad, 1833.

This well-known and variable species is of wide distribution. Short, high specimens form the variety triquQtr^ Q£

1833. 

1838. 

184J. 

1843. 

1845.

1845.

1856.

1863.

1863.

1863.

1863.

1894.

1898.

1932

which crassidens is a young shell. Conrad, by the extraordinary carelessness which was norma]L to him, placed the tw» 

latter names under Mulinia, while congesta appears both as 

Hemimactra and as Standella in different places in the same 

list of Miocene fossils printed in 1863!—Dall, 1898.

Dimensions of figured specimens: U. S. Nat. Mus.

325602. right valve, height 15.5 millimeters, width 21.0 

millimeters, convexity 5.6 millimeters; left valve of 

another individual, height 15.3 millimeters, width 22.0 

millimeters, convexity 5.5 millimeters. U. S. Nat. Mus.

325603. right valve, height 23.0 millimeters, width. 25.5 

millimeters, convexity 9.5 millimeters; left valve of 

another individual, height 24.5 millimeters, width 26.5 

millimeters, convexity 10.0 millimeters.

Locality of figured specimens: U. S. Nat. Mus. 

325602, Yorktown formation, 1 mile northeast of Suffolk, Nansemond County, Va.; U. S. Nat. Mus. 325603, 

Yorktown formation, iy2 miles west of Smithfield, 

Isle of Wight County, Va.

Mulinia cpngesta (Conrad) is one of the most easily 

recognized representatives of the pelecypod fauna of 

the east coast Miocene. It has been reported from the 

majority of North Carolina and Virginia localities at 

which the fossiliferous Miocene occurs, and in number 

of individuals it generally exceeds all other bivalves. 

At some of the exposures in southern Virginia and 

northern North Carolina, on the Meherrin Eiver in 

Southampton County,-Va., for example, and in the 

vicinity of Murfreesbpro, Hertford County, N. C., the 

marls are literally packed with this shell. The form 

varies rather widely in .size and outline, though the 

characters are usually fairly constant at a single locality. 

The majority of the forms from the Meherrin Kiver 

outcrops correspond closely to the type of Conrad's 

M. congesta. They are commonly smaller than those 

at Yorktown and are relatively lower with a more produced posterior margin and more proximate umbones. 

In the later Yorktown fauna, on the other hand, the species is of the larger, heavier, subequilateral, triangular 

type, and thus follows the line of Variation represented 

by M. triquetra Conrad. This variant is particularly 

abundant in the environs of Suffolk, Nansemond 

, County, Va. Near Exit, in the same county, the shells 

are remarkable for the preservation of the concentric color markings. M. congesta of the Duplin 

fauna is inconstant. Though often of medium size, individuals from the vicinity of Clinton, Sampson 

County N. C., reach a height of 26.5 millimeters and a 

width of 35.0 millimeters, and near Lumberton, in 

Robeson County, N. C., they commonly measure 24 

to 26 millimeters in height, with a corresponding width 

of 34 to 34.5 millimeters. These large Duplin forms 

differ, however, from those of the Yorktown fauna in 

the produced posterior margin. The oval, elongate 

forms were set aside by Dall under the manuscript 

name elongata. They have been given subspecific rank, 

for they are distinct and readily separable; though, on
114 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

the other hand, they are connected with the normal 

representatives of the species by an unbroken gradational series.

Mulinia congest a (Conrad) is distinguished from the 

later and much less abundant M. lateralis (Say) by 

the heavier, usually larger shell and the more robust • 

hinge. Both species vary widely in outline, but the 

former is, for the most part, less triangular and more 

equilateral.

Mansfield records M. congesta from each of the three 

zones of the Choctawhatchee formation of Florida but 

"only one small valve has been collected from the Area 

zone." He reported it to be one of the most common 

species in the Ecphora zone and observed that "the 

shells are larger, thicker, and have Stronger laterals in 

the Ecphora zone than in the Cancellaria zone."

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Lanexa (upper bed), New Kent County; 

Petersburg, Dinwiddie County; 5 miles northeast of Smithfield, 1% miles northeast of Smithfield, 2 miles west of Smithfield, iy2 miles west of "Smithfield, and Benns Church, Isle of 

Wight County; 2% to 3 miles northwest of Zuni, 2 miles northwest of Zuni, 1% miles above Zuni, 1 mile north of Zuni, % 

mile north of Zuni, Zuni (near the pumping station), 6^ to 7 

miles below Zuni, 7 to 7^ miles below Zuni, and 8 to 8% 

miles below Zuni, Isle of Wight County; Hitchcock, Greensville 

County; Sycamore ? Harcum's store, M to % mile below Sycamore, the lower Seaboard Railway bridge, and Maddelys 

Bluff, Southampton County; 2 miles below South Quay; % 

mile north of Chuckatuck, Chuckatuck mill dam, Everets, 

Exit, iy2 miles southeast of Reids Ferry, 1% miles north of 

Suffolk, 1% miles north of Suffolk, 5y2 miles northwest of 

Suffolk, 2% miles northwest of Suffolk, !*,£ miles northwest of 

Suffolk, 1 mile west of Suffolk, 1% miles northeast of Suffolk. 

1 mile northeast of Suffolk, y2 mile below the Suffolk waterworks dam, and the drainage ditch of the Norfolk & Western 

Railway just east of Jericho ditch, Nansemond County.

North Carolina: Miocene, Yorljtown formation, 3 to 4 miles 

below the lower Seaboard Railway bridge over the Meherrin 

River, 1% miles above Branches Bridge, 1 mile above Branches 

Bridge, Branches Bridge, and 1% miles below Branches Bridge, 

Northampton County; 2% miles northwest of Murfreesboro (at 

Watsons Mill on Kirbys Creek), 1% miles above Murfreesboro, 

1 mile above Murfreesboro, and near Murfreesboro, Hertford 

County; Tar Ferry on Wiccacon Creek (opposite Harrellsville), 

1% miles below Tar Ferry, 3 to 4 miles below Tar Ferry, 

Dogwood Landing, and Mount Pleasant Landing on the Chowan 

River, Hertford County; Colerain Landing, Bertie County; 

1 to 2 miles above the Atlantic Coast Line Railroad bridge, 

Halifax (at Quankey Creek, just below the county bridge), 

1% miles northeast of Enfield, % mile west of Enfield, Palmyra 

Bluff, and 3% miles below Palmyra Bluff, Halifax County; 

1% miles east of Battleboro, 3 miles south of Battleboro, 

and 2 miles southeast of Sharpsburg, Nash County; 3% 

miles northwest of Rocky Mount, 2 miles west of Rocky 

Mount, % mile northwest of the Rocky Mount waterworks, % 

mile north of the Rocky Mount waterworks, 6 to 7 miles below 

Rocky Mount (at Capt. Turner Battle's), Compass Creek (at a 

point 1 mile from the confluence with the Tar), % mile north 

of New Bridge, 5 miles below New Bridge, Swift Creek, 15% 

miles above Bells Bridge, % mile above Bells Bridge, 100 yards 

below Bells Bridge, % mile below Bells Bridge, 1 mile below 

Bells Bridge, Shiloh Mills, and 1 mile below old Sparta Bridge, 

Edgecombe County; Hamilton Bluff, ys mile below Hamilton

Landing, 2 miles southeast of Hamilton Bluff (at old fort), 

and 2% miles northwest of Williamston (on Joseph Cherry's 

farm), Martin County; 2 miles below Toddy Station, 2 miles 

southeast of Tugwell (on Jacobs Branch), 1*4 miles northeast 

of Farmville, 3 miles south of Farmville, 2% miles north of 

Standard, near Standard, 8 miles southwest of Frog Level (on 

J. A. Nobles branch), 8 to 9 miles west of Greenville (on the 

east side of Pinelog Branch), 3 miles west of Greenville (on 

Schoolhouse Branch), Greenville (just east of the county 

bridge), 6% miles below Greenville (at Tafts Landing), 8 to 9 

miles southeast of Greenville, 1% miles west of Galloway 

Crossroads, and 9 to 10 miles south of Greenville, Pitt County; 

2% miles northwest of Chocowinity, and 1^ miles northeast 

of Chocowinity, Beaufort County; 2 miles southwest of Maple 

Cypress, Rock Landing, Craven County; 1 mile west of Wilson 

(in Hominy Swamp), 3 miles east-southeast of Wilson, 5 miles 

south of Wilson, and 7 miles southeast of Wilson, Wilson 

County; 6 miles west of Goldsboro, Wayne County; 1 mile 

north of Castoria, % mile east of Lizzie, 1 mile east of Lizzie, 

4 miles east of Lizzie (on Dog Swamp), and 1% miles east of 

Ormondsville, Greene County. Duplin marl, 3 miles south of 

Clinton (on Gum Chimney Branch), 4 miles south of Clinton, 

and 10 miles south of Clinton, Sampson County; 2 miles northeast of Warsaw, Natural Well, drainage ditch just east of railroad, IT/2 miles north of Magnolia, and Magnolia (at Frank 

Wilson's marl pit), Duplin County; 4 miles north of Lumberton 

(on Berry Godwin's plantation), 1 mile west of Lumberton, 

Lumberton (near the bottling works), 2 miles below Lumberton, 

4 to 5 miles below Lumberton, Fairmont, 1% miles northeast 

of Fairmont, 4 miles northeast of Fairmont, and 2 miles northwest of Barnesville, Robeson County. Pliocene, Waccamaw formation, Walkers Bluff, Cape Fear River, Bladen County; Lake 

Waccamaw, Columbus County; Wilmington (at the city rock 

quarry), New Hanover County.

Outside distribution: Miocene, Choctawhatchee formation, 

northern Florida. Choptank formation, (?) Atlantic City (well 

bore), N. J. Duplin marl, Muldrow Place, Sumter County, 

S. C.; Porters Landing on the Savannah River, Effingham 

County; Brunswick River bed, Brunswick, Glynn County, Ga. 

Pliocene, Caloosahatehee marl, Nashua, Putnam County, Fla.; 

De Leon Springs, Volusia County, Fla. Croatan sand, Slocums 

Creek and Mallisons, Craven County, N. C.

Mulinia congesta magnoliana (Dall) Gardner

1898. Spisula (Hemimactra?) magnoliana Dall, Wagner Free 

Inst. Sci. Trans, vol. 3, pt. 4, p. 899, pi. 27, fig. 29.

Shell small, equilateral, somewhat compressed, with small, 

little-elevated, pointed, adjacent beaks; surface smooth except 

for lines of growth and a feeble angulation extending backward from the umbo to the lower posterior margin; ends nearly 

equally rounded, the posterior slightly more pointed, the base 

moderately and evenly curved; pallial sinus small, angular, very 

short; hinge normal, feeble, -with short granulose laterals. 

Longitude 17, altitude 10, diameter 7 millimeters.—Dall, 1898.

Holotype, a left valve: U. S. Nat. Mus. 115080.

Type locality: Magnolia, Duplin County, N. C.

In the unique valve that was taken as the type of 

Spisula magnoliana Dall, the cardinal margin is broken 

away and the edges are so perfectly rounded by erosion 

that all trace of the characteristic ligamentary attachment of Mwlinia has been obliterated and replaced by a 

pseudospisuloid attachment. This fact was .brought 

out by the examination of fresh individuals in which 

the septum had been recently shipped away.
PART 1. PELECYPODA 115

The subspecies is separated from M. congesta s. s. 

by the lower, more regularly oval and elongate valves, 

the less prominent umbones, and the short, rather 

heavy laterals.

Distribution: Virginia: Miocene, Yorktown formation, South 

Quay, Nansemond County.

North Carolina: Miocene, Yorktown formation, S1/^ miles 

below Palmyra Bluff, Halifax County; 8 to 9 miles south of 

Greenville, Pitt County; 1 mile north of Castoria, Greene 

County; Rock Landing, Craven County. Duplin marl, 10 miles 

'south, of Clinton, Sampson County; Natural Well, Duplin 

County; 2 miles below Lumberton, Robeson County. Pliocene, 

Waccamaw formation, Walkers Bluff, Bladen County; Neills 

Eddy Landing, Columbus County. .

Outside distribution: Miocene, Duplin marl, Brunswick River 

bed, Brunswick, Glynn County, Ga.

Family MESODESMATIDAE 

Genus MESODESMA Deshayes

1831, Mesodesma Deshayes, Encyclopedie rfle'thodique, vers. 

vol. 2, p. 442.

Type by subsequent designation (Anton, Verzeichniss der 

Conchylien, p. 3, Halle, 1839) : Mactra donacia Lamarck. Recent off the coast of Chile.

Shell heavy, compressed, donaciform or subtrigonal, 

inequilateral. Umbones posterior. Ligament short, 

mostly internal. Hinge strong. Resilial pit deep. A 

single cardinal in each valve, that of the left usually 

stronger and often bifid. Anterior and posterior sulcated laterals in the left valve received between the 

sulcated laminae of the right. Inner margin of valves 

smooth. Muscle impressions deep. Pallial sinus well 

defined, variable.

The genus is first recognized in the Eocene. The 

Recent species are relatively few, but they are worldwide in distribution.

Mesodesma spatha Gardner, n. sp.

' . Plate 18, figures 8, 12

Shell small, compressed, ovate-oblong, strongly inequilateral. Umbones very low and flattened, located 

about two-thirds of the distance back. Anterior portion of shell slightly contracted, much produced, gently 

sloping dorsally, evenly rounded distally. Posterior 

dorsal margin slightly hunched. Lateral margin subtruncate. Base line nearly straight. Surface smooth 

or marked with feeble incrementals. Hinge known 

from right valve only; hinge plate heavy. Resilial 

pit large and deep, slightly oblique; limiting margins 

raised. Lateral furrows narrow, deep, transversely 

grooved, the posterior decidedly shorter. Anterior 

arm of cardinal in line with the anterior ventral lamina 

but not confluent with it; posterior arm projecting almost horizontally over the chondrophore. Lateral 

sockets deep. Muscle impressions and pallial characters distinct. Anterior adductor scar pyriform; posterior semielliptical. Pallial line rather distant from

the hinge margin. Sinus evenly rounded, projected 

forward as far as the umbones.

Dimensions of holotype: Height 6.4 millimeters, 

width 10.3 millimeters, convexity 1.7 millimeters. •

Holotype, a right valve: U. S. Nat. Mus. 325591.

Type locality: 1 mile northeast of Suffolk, Nansemond County, Va. Yorktown formation.

This single valve, the only one* of the genus thus 

far reported from the east coast Miocene, has many 

characters hi common with Mesodesma deauratum 

Turton of the Pleistocene faunas of the North Atlantic 

coast and may be the precursor of that species. The 

umbones are more posterior than in the majority of 

the Recent individuals; the hinge plate is set in the 

plane of the dorsal margins rather than slightly oblique to it, as in the M. deauratum of Turton; and the 

ventral laminae of the laterals and the anterior arm 

of the cardinals are less elevated. The species also 

suggests at first glance Spisula modicella Conrad. It 

is, however, relatively lower, more inequilateral, with a 

much more deeply excavated resilial pit and shorter 

and more narrow lateral grooves.

Distribution: Virginia: Miocene, Yorktown formation, 1 mile 

northeast of Suffolk, Nansemond County.

Genus ERVILIA Turton

1822. Ervilia Turton, Conchylia insularum britannicarum: 

Dithyra, p. 55.

Type by monotypy: Mya nitens Montagu. Recent from the 

Tortugas to the northern coast of South America.

Shell small, oval to triangular. Umbones low, subcentral, slightly opisthogyrate. External ligament obsolete; internal, lodged in a small resilifer, situated 

between the anterior and posterior cardinals. Lateral 

armature feeble; grooves developed in right valve; lateral teeth of left usually replaced by modifications of 

the dorsal margins. Pallial sinus well defined.

These lentil-shaped bivalves form an inconspicuous 

factor in the marine faunas of the Tertiary and postTertiary seas. The Recent forms are mostly tropical.

Ervilia lata Dall

Plate 23, figure 20

1898. Ervilia lata Dall, Wagner Free Inst. Sci.- Trans., vol. 3,

pt. 4, p. 915, pi. 33, fig. 20. 

1932. Ervilia lata Dall. Mansfield, Florida Geol. Survey BulL 8,

p. 155, pi. 32, figs. 4, 7,10.

Small, very similar to E. concentrica, from which it differs 

by being broader between the beak and the basal margin, with 

the beaks slightly more equilateral and the dorsal margin 

behind the umbo usually more impressed; the surface is usually 

covered with concentric ridges, which are flattened and coarser 

and less regular than those of E. concentrica; the hinge teeth 

also are less strong than the latter species. Longitude 4.5 [5.2], 

altitude 3.5 [3.6], diameter 2.2 millimeters. 

• This form on casual inspection would be referred to E. conce^trica as a mere variety, but when a large number of specimens are examined and the characters above-mentioned seem
116 MOLLTJSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

to be fairly constant, I believe it is best to recognize the 

average differences by a name than to overlook them by 

consolidation with what I regard as probably a distinct 

species.—Dall, 1898.

Holotype, a right valve: U. S. Nat. Mus. 115054. 

Type locality: Natural Well, Duplin County, N. C. 

Duplin marl.

Distribution: Nortfl Carolina: Miocene, Duplin marl, 1% 

miles north of Magnolia and at Frank Wilson's marl'pit near 

Magnolia, Duplin County. Pliocene, Waccamaw formation, 

Cronly and Neills Eddy Landing 3 miles north of Cronly on 

the Cape Fear River, Columbus County.

Ervilia lata radiata Gardner, n. subsp.

Plate 23, figures 25, 29

Shell minute, oblong to subtriangular, slightly inequilateral. Umbones subcentral or a little in front 

of the medial line, opisthogyrate. Dorsal margins 

fairly steep; anterior lateral margin evenly rounded, 

posterior slightly produced and rounded. Base line 

strongly arcuate, often slightly contracted posteriorly. 

Surface sculptured with crowded concentric lirae, 

which vary rather widely in strength in different individuals, and on the posterior slope, with distinct 

though submicroscopic radial striations. Ligament pit 

moderately large. Anterior cardinal of right valve 

strong, the posterior obsolete. Anterior lateral groove 

ill defined, posterior less feeble; dorsal edges of left 

valve modified to function as laterals. Pallial sinus 

rather deep, well rounded.

Dimensions of holotype: Height 2.6 millimeter's, 

width 4.0 millimeters, convexity 0.8 millimeter. Paratype: Height 2.6 millimeters, width 4.2 millimeters.

Holotype, a right valve, and paratype, a left valve: 

U. S. Nat. Mus. 325597.

Type locality: Neills Eddy Landing on the Cape 

Fear River, Columbus County, N. C. Waccamaw 

formation.

Ervilia lata radiata differs from E. lata s.s. by the 

lower, less triangular outline, by the tendency toward 

a less regular and less clearly defined concentric sculpture, and preeminently by the radial striations of the 

posterior keel. The subspecies is best developed at 

the type locality, Neills Eddy Landing, in the Waccamaw, though it is present in the Yorktown and is 

associated with E. lata Dall in the Duplin. The concentric and radial sculpture serve also to separate 

the subspecies radiata from the coexistent E. polita 

Dall.

Less than half a dozen valves of this small species 

were recovered by Mansfield from the Gancellaria zone 

of the Choctawhatchee formation in Florida.

A closely related species, E. gabbi Woodring, is described by Woodring, 1925, from the Bowden of 

Jamaica. He differentiated it from the southeastern 

.American species because it is less compressed and less 

inequilateral.

Distribution: Virginia: Miocene, Yorktown formation, 1 mile 

northeast of Suffolk, Nansemond County.

North Carolina: Miocene, Dupljn marl, Frank Wilson's marl 

pit near Magnolia, Duplin County. Pliocene, Waccamaw formation, Neills Eddy Landing, Columbus County.

Superfamily VENERACEA Menke

Family PETRICOLIDAE D'OrMgny

Genus FETRICOLA Lamarck

1801. Petricola Lamarck, Systeme des animaux sans vertebres, 

p. 121.

Type by subsequent designation (Schmidt, C. F., Versuch 

fiber die beste Einricht, etc., pp. 55, 176., Gotha, 1818) ; Venus 

lapicida Chemnitz. Found by Chemnitz in ballast of coral rock 

from the West Indies.

Shell thin, oval or elongate, often irregular, gaping. 

Umbones anterior but not terminal. Lunule ill defined. 

Sculpture dominantly radial and in the genotype divaricate or zigzag. Inner margins smooth. Ligament 

external, attached to nymphs. Armature of right valve 

usually consisting of two cardinals, the posterior of 

which is grooved or bifid; third rudimentary cardinal 

rarely present; left valve furnished either with three 

divergent cardinals (the middle one bifid, the remaining two simple) or with two divergent cardinals (a 

simple posterior and a bifid anterior); laterals absent 

in the normal adult. Pallial sinus narrow, as a rule, 

and ascending, with considerable variation in depth.

This is a nestling or burrowing genus, which exhibits 

the variability characteristic of dwellers in such a 

habitat.

The group has been recognized from strata as early as 

the Cretaceous; the Recent species, though numbering 

only about 25, are, owing in part to their habitat, widely 

distributed in the temperate and warm waters.

Petricdla s.s. has not been recognized in the Miocene 

or in the pre~Caloosahatchee Pliocene. Dall reports 

the genotype from the Caloosahatchee marl. Possibly 

the temperature of the water may have been the controlling factor that excluded it from the early Pliocene 

of the Carolinas, although it is recorded in the Recent 

faunas from the coast of South Carolina.

Subgenus RUPELLARIA Fleuriau-Bellevue

1802. Rupellaria, Fleuriau-Bellevue, Jour, physique, vol. 54, p.

347; Soc. Philom. (Paris) Bull, des Sciences, 62, p. 106. 

1900. Rupellaria, Dall, Wagner Free Inst. Sci. Trans., vol. 3,

pt. 5, p. 1058.

Type by elimination: Venus lithophaga Retzius. Widely reported but most 'common off the Atlantic coasts of France and 

Spain and in the western Mediterranean.

Fleuriau-Bellevue cited two species under his newly 

described genus: the first a Venerupis, the second 

Venus lithophaga Retzius, which be'comes by elimination the type of the subgenus.

Rupellaria is short and inflated in front, less inflated 

and attenuated behind. A radial sculpture is usually
PART 1. PELECYPODA 117

developed over the entire shell but is stronger anteriorly. The pallial sinus is broad and broadly 

rounded.

Petricola (Rupellaria) grinnelli Olsson 

Plate 15, figures 13, 14, 18

1914. Petricola (Claudiconcha) grinnelli Olsson, Bull. Am. Paleontology, vol. 5, No. 24, p. 16, pi. 4, figs. 7-10.

Shell elongated, solid, often distorted; anterior end rounded; 

posterior end elongated, pointed; right valve slightly larger 

and overlapping the left, especially on the posterior dorsal 

margin^ surface sculpture of irregular radial striae, which as 

a rule are slightly larger and separated by wider interspaces 

on the anterior portion of the shell; striae more or less granulated by concentric lines; hinge weak, with slender teeth, 

those in the specimens broken off but, judging from the stumps 

remaining, consisting of three cardinal teeth in each valve.

Type specimen : Length 22, height 13, thickness 12 millimeters.

A large valve: Length 25, height 16, thickness 7 millimeters.

The subgenus Claudiconcha Fischer, as exemplified by P. 

monstrosa Gmelin, contains shells which have the right valve 

slightly larger and overlapping on the left. This species 

probably burrowed in the sand. The Miocene shell compares 

well with the type form of this subgenus but possesses a much 

more degenerate hinge.

Yorktown formation, .Tames River, 5 miles north of Smithfield; Bellefield.—Olsson, 1914.

The Chemnitz figures to which Gmelin refers in his 

citation of monstrosa indicate a shell unlike grinnelli. 

Olsson's species, seems more properly referable to 

Rupellaria.

The shell is built up of concentric layers, and the 

successive laminae are often visible in cross section at 

the inner margins of the valves. The outline is 

strongly convex, oval, cylindrical, or trapezoidal. The 

dorsal margins are usually rectilinear, the anterior 

sometimes flaring widely, the posterior parallel with 

the base. The lateral margins are evenly and similarly 

rounded or obscurely truncated at approximately the 

same angle to the base. The umbones are inflated, 

incurved to the dorsal margins, their tips proximate 

and prosogyrate, and located about one-third of the 

distance back from the anterior margin. The surface 

is sculptured with some 40 irregular radials, mostly 

equisize and equispaced but slightly more crowded posteriorly. The free edges of the concentric lamellae are 

ruffled at the intersection with the ribs. The lunule is 

not defined. The ligament is external and seated on a 

very narrow nymph. The 2 right cardinals are proximate, slender, conical, recurved, issuing from beneath 

the umbo. The dentition of the left valve is imperfectly known. The anterior adductor impression is 

oval, the posterior suborbicular, and both of them are 

set well up toward the dorsal margin. The pallial 

line and sinus are strongly marked. The sinus is very 

broad and somewhat oblique, the frontal margin 

rounded and not far from the median vertical; the 

ventral margin parallel to but not coalescent with the 

pallial line.

Dimensions «f figured specimens: Eight valve (U. S. 

Nat. Mus. 325562, from Palmyra Bluff on the Roanoke 

River, Halifax County, N. C.), height 13.5 millimeters, 

width 23.5 millimeters, convexity 5.5 millimeters.' Left 

valve (U. S. Nat. Mus. 325561, from Wilmington, 

N. C.), height, 16.0± millimeters, width 24.8 millimeters, convexity 5.8 millimeters.

P. grinnelti Olsson is characterized by the laminar 

texture, the irregular Pleiorytis-likQ radials, distributed with approximate uniformity over the .entire external surface, and the bizarre outline of the pallial 

line and sinus, which is due to the elevated position of 

the adductors. Almost any of these characters alone 

would suffice to differentiate the species.

Distribution: Virginia: Miocene, Yorktown formation, Bellefield on the York River, York County; Petersburg, Dinwiddie 

County; 5 miles north of Smithfield on the James River, Isle of 

Wight County; Suffolk, Nansemond County.

North Carolina: Miocene, Yorktown formation, Palmyra 

Bluff, Halifax County; 1% miles below Bells Bridge, Tar River, 

Edgecombe County. Pliocene, Waccamaw formation, Walkers 

Bluff (?), Bladen County; Wilmington(?), New Hanover 

County.

Subgenus PETRICOIARIA Stoliczka

1871. Petricolaria Stoliczka, India Geol. Survey Mem., Palaeontologia Indica, Cretaceous fauna of southern India, 

vol. 3, p. 139.

Type toy original designation: Petricola, pholadiformis 

Lamarck. Recent from Prince Edward Island to the West 

Indies and the Gulf of Mexico.

In this the shell is very much elongated, subcylindrical, the 

sinus narrow and very deep; the hinge has 2 teeth in each 

valve, attached below the hinge area and curving upward; in 

the right valve the anterior tooth is hooklike, the posterior 

much larger, broadly laminar and bipartite; in the left the 

anterior is very large and bipartite, its anterior portion almost 

representing a separate hooklike tooth corresponding to the 

anterior tooth of the right valve; the posterior portion is thick 

and prominent and longitudinally grooved; besides this there 

is a small, sometimes obsolete, posterior cardinal tooth.— 

Stoliczka, 1870.

Petricola (Petricolaria) pholadiformis Lamarck

1818. Petricola pholadiformis Lamarck, Histoire naturelle des

animaux sans vertebres, vol. 5, p. 505. 

1822. Petricola fornicata Say, ,Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 2, p. 319. 

1832. Petricola pholadiformis Lamarck. Conrad, American

marine conchology, p. 37, pi. 7, fig. 3.

1834. Petricola pholadiformis Lamarck. Say, American conchology, pt. 6, pi. 60 (upper and lower figs.). 

1841. Petricola pholadiformis Lamarck. Gould, Invertebrata

of Massachusetts, p. 63. 

1854. Petricola pholadiformis Lamarck. Sowerby, Thesaurus

conchyliorum, pt. 15, p. 771, pi. 166, fig. 1. 

1858. Petricola pholadiformis Lamarck. Holmes, Post-Pleiocene

fossils of South Carolina, p. 38, pi. 7, fig. 6. 

1889. Petricola pholadiformis Lamarck. Dall, TJ. S. Nat. Mus.

Bull. 37, p. 58, pi. 59, fig. 15; pi. 64, fig. 140a. 

1900. Petricola (Petricolaria) pholadiformis Lamarck. Dall,

Wagner Free liast. Sci. Trans., vol. 3, pt. 5, p. 1061.
118 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

1906. Petricola pholadiformis Lamarck. ClarE, Maryland Geol. 

Survey, Pliocene and Pleistocene, p. 201.

P. testa transversim elongata; latere postico brevissimo, 

sulcis longitudinalibus Inmelloso-dentatis utrinque radiato; 

antico subglabro . . . Largeur, 46 millim.—Lamarck, 1818.

The species is characterized by a cylindrical outline, 

by a strong differentiation of the sculpture on the- anterior and posterior portions of the shell, and by the 

relatively few but prominent denticulated radials on 

the anterior end. There are 3 cardinals in the left 

valve—the middle one sulcated, the anterior and 

posterior ones simple.

Distribution* Virginia: Miocene, Yorktown formation, Yorktown, York County.

North Carolina: Pliocene, Waccamaw formation, Walkers 

Bluff, Bladen County; Neills Eddy Landing, 3 miles north of 

Cronly, Columbus County.

Outside distribution: Pleistocene, Sankaty Head (early 

fauna), Mass.; Wailes Bluff near Cornfield Harbor, St. Marys 

County, Md.; Eau Gallie, Brevard County, Fla. Recent, Prince 

Edward Island to Greytown, Nicaragua, in less than 50 fathoms; 

most abundant on sandy and muddy bottoms.

Petricola (Petricolaria) carolinensis Conrad

1856. Petricola pholadiformis Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 87, pi. 21, fig. 5. Not 

P. pholadiformis Lamarck, 1818.

1863. Petricola carolinensis Conrad, Acad. Nat. Sci. Philadelphia Proc. for 1862, p. 576. (New name for P. 

pholadiformis Tucmey and Holmes.)

1900. Petricola (Petricolaria) carolinensis Conrad. Ball, Wagner Free Inst. Sci. Trans., vol. 3, pt. 5, p. 1060.

Shell elongated, cylindrical, buccal side very short, radiately 

[costate] and striate; ribs lamellar; anal side much elongated, 

radiately striate; lunule ovate. . . . The shell is ovate-cylindrical, equivalve, but very unequilateral; the buccal side is 

rounded and covered with irregular lamellar and somewhat 

toothed ribs; anal side covered with radiating irregular raised 

lines. The lunule is defined by the termination of the lines 

of growth.—Tuomey and Holmes, 1856.

Locality: Pee Dee and Smiths, Goose Creek, S. C. 

' Valves gaping, strongly convex, elongate-ovate, very 

inequilateral. Anterior end short and evenly rounded; 

posterior, alar, produced, tapering gradually to the 

acutely rounded extremity. Umbones tumid, proximate, prosogyrate, located about one-fifth of the distance back from the anterior margin. Radial sculpture 

on the anterior part of the shell coarse and distant, the 

posterior • of the primary radials originating at the 

umbones and reaching the ventral margin a little in 

front of the median line; remainder of shell covered 

with fine and uniform radiating striae, some 50 to 70 

in number. Concentric lines inconsequential except on 

the anterior end, where they tend to become scabrous 

at the intersection with the prominent radials. Lunule delimited by the anterior radial. Escutcheon not 

defined. Ligament external; nymphs elongated, lenticular in the closed valves, with a deep groove at their 

ventral margins. Armature in right valve consisting

of a stout, projecting, slightly recurved, anterior cardinal, and a laminar, sulcated, posterior cardinal; in the 

left valve 3 divergent teeth—the anterior cardinal 

simple, the middle cardinal feebly sulcated on the ven-- 

tral surface, and the posterior cardinal simple and 

laminar. Anterior adductor muscle impressions subcircular; the posterior semieHiptical. Sinus free, extending about half the distance toward the anterior 

margin, rounded in front, its dorsal and ventral 

boundaries parallel. Pallial line usually indistinct. 

Inner margins of valve often crenate, particularly in 

front.

Petricola carolinensis Conrad is separated from P. 

pholadiformis Lamarck by the less strongly differentiated sculpture of the anterior and posterior areas. The 

radials as a whole are more numerous and consequently 

less prominent and distant. The concentric sculpture 

is laminar at its intersection with the radial, but the 

edges are rarely free and vaulted as in P. pholadiformis. P. carolinensis is most closely allied to the 

Recent P. dactylus Sowerby, from which it differs in. 

being constantly more elongated and cylindrical. The 

general characters of the sculpture are very similar. 

The Tertiary species is on the whole rather rare, though 

in the Duplin marl, in Robeson County, well preserved 

individuals have been collected in considerable 

numbers.

Distribution: North Carolina: Miocene, Yorktown formation, 

2% miles northwest of Williamston (on the farm of Joseph 

Cherry), Martin County. Duplin marl, 2 miles below Lumber ton, 1% miles northeast of Fairmont (on the farm of 

Andrew Jones), and at Fairmont, Robeson County.

Outside distribution: Pliocene, Waccamaw formation, Goose 

Creek and Pee Dee River, S. C.

Genus PLEIORYTIS Conrad

1862. Pleiorytis, Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, p. 286. 

1936. Pleiorytis Conrad. Gardner, Florida Dept. Cons. Geol.

Bull. 14, p. 39.

Type by monotypy: Pleiorytis ovata Conrad (Days Point, 

James River, Va.) = Petricola centenaria Conrad, 1833. Middle and upper Miocene of the middle and south Atlantic 

Coastal Plain.

Equivalve, ovate or oval, with radiating striae, gaping posteriorly; hinge of right valve with 2 widely diverging teeth; 

left valve with 1 direct, thick, triangular, bifid tooth under 

the apex, and an oblique compressed tooth posteriorly; sinus 

of pallial impression extending beyond the middle of the valves; 

muscular impressions large. (Miocene.)—Conrad, 1862.

Conrad placed this genus under the family Petricolidae.

The group of Pleiorytis centenaria Conrad has a 

limited geographic and stratigraphic range, and perhaps for that reason its dissimilarity to the type of 

Asaphis (Venus deflorata Linnaeus from the Bahamas) was not noted by Ball and others in assigning 

centenaria to Asaphis. In Asaphis, as in many of the
PART 1. PELECYPODA 119

tellinids, the tips of the umbones are bent inward and 

very slightly backward, and no trace of a lunular spur 

appears across the cardinals. In Pleiorytis, as in 

Petricola and other venerids, the umbones are decidedly 

prosogyrate, and the lunular spur is more or less developed. In AsapMs the bifid cardinal of the right 

valve is produced and oblique; in Fleiorytis it is short 

and nearly vertical. In Asaphis, in the left valve, the 

dorsal margin is tabulated in front of the bifid cardinal; in Pleiorytis there is a well-developed laminar, 

left anterior cardinal.

The general relations of Pleiorytis were properly 

indicated by Conrad, and though possibly it should be 

given only subgeneric rank under Petricola, the habits 

of the animal are not those of typical Petricola, the shell 

is not adjusted to a boring habitat, and the consequent 

differences may be recognized generically. The genus 

may then be described as follows:

Shell of moderate dimensions, rather thin, slightly 

gaping; transversely elongate, moderately inflated. 

Umbones anterior, not conspicuously prominent, the 

tips proximate and prosogyrate. Lunule and escutcheon not developed. Posterior area flattened but 

not rostrate. Ligament strong, external. A slender 

spur from the lunular region carried across the 

cardinals. Teeth short, built up from a narrow 

hinge plate; a laminar anterior and bifid medial 

cardinal in the right valve, the posterior cardinal 

almost or entirely obsolete; a laminar anterior, 

bifid medial, and laminar posterior cardinal in the 

left valve. Laterals not developed. Adductor scars 

large, the pallial sinus broad and deep, not confluent 

ventrally with the pallial line. Inner edges of the 

valves simple or faintly rayed but not crenate.

The group is particularly characteristic of the middle and upper Miocene of the eastern seaboard of the 

United States.

Petricola (Rupellaria) harrisii Dall has a hinge 

identical with that of Pleiorytis centenaria and may, 

as indicated by Mansfield,49 be nothing more than a 

much-warped individual of that species. Warping is 

not common in the group, but it is present to a considerable degree in a few individuals. Petricola 

(Petricolaria) calvertensis Dall is-similar in sculpture 

but it more cylindrical and, though the hinge is rather 

badly broken, does not seem to have the hinge plate so 

well developed as that of Pleiorytis.

, Pleiorytis centenaria (Conrad) Conrad?

Plate 15, figure 17

1833. Petricola centenaria Conrad?, Am. Jour. Sci., 1st ser., 

vol. 23, p. 341.

1863. Pliorytis centenaria Conrad?, Acad. Nat. Sci. Philadelphia Proc. for 1862, vol. 14, p. 576.

1900. Petricola (Rupellaria) harrisii Dall, Wagner Free Inst. 

Sci. Trans., vol. 3, pt. 5, p. 1060, pi. 43, fig. 1.

49 Mansfield, W. C., Florida Geol. Survey Bull. 8, p. 149, 1932,

1932. -Asaphis centenaria (Conrad). Mansfield, Florida Geol. 

Survey Bull. 8, p. 149^ pi. 31, fig. 4.

Shell solid, ovate, distorted more or less by the irregularities 

of its situs; posterior end blunt, longer; anterior end shorter, 

rounded; sculpture of fine, nearly uniform, radial, rounded 

threads with wider interspaces, crossed by fine, rounded, 

slightly elevated incremental lines; beak moderately elevated; 

hinge short, with (in the left valve) 1 strong, apically grooved 

cardinal between 2 simple narrow diverging teeth; ligamentary nymph short, strong, deeply grooved; basal margin feebly 

crenulated by the external sculpture; pallial sinus wide, shallow; altitude 20 [20.5], latitude 23 [22.5]; semidiameter 7 

millimeters.

Only 1 valve of this species was obtained by Professor Harris, 

in whose honor it is named.—Dall, 1900.

Holotype of P. harrisii Dall, a left valve: U. S. Nat. 

Mus. 145020.

Type locality: Bellefield.Bluff, 4^/2 miles above Yorktown, Va. Yorktown formation.

Mansfield was the first to suggest that Petricola 

harrisii Dall should fall into the synonymy of "Asaphis" centenaria Conrad.

Family COOPERE1LIDAE 

Genus COOPEREILA Carpenter

1864. Cooperella Carpenter, British Assoc. Advancement Sci.

Kept, for 1863, p. 639. 

1900. Cooperella Carpenter. Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p. 1061.

Type by monotypy: Cooperella scintilloeformis Carpenter= 

Oedalia subdiaphana Carpenter. Recent on the Pacific coast 

between Vancouver and Todos Santos Bay.

New subgenus of Oedalia. Cartilage semi-internal; only 1 

tooth bifid.—Carpenter, 1864.

Shell small, thin, smooth, or concentrically striate or undulate, equivalve, nearly equilateral, with entire margins; ligament long, feeble, profuse, amphidetic; resilium short, stout, 

opisthodetic, immersed behind the cardinals on an oblique thickening of the hingeplate, not excavated to form a pit or produced into a chondrophore; hingeplate narrow, carrying two 

right and three left subumbonal, divaricating, short, cardinal 

teeth, of which the left central tooth is always, and the others 

frequently, bifid; laterals none; muscular impressions small, 

oval; pallial line narrow with an ample sinus.—Dall, 1900.

This small genus has a very interesting distribution. 

Only a few species of Cooperella s. s. have been recognized—a single species from the east coast Tertiary; 

the others, including the genotype, from the Pleistocene 

and Recent of the west coast. Woodring, 1925, described a species from the Bowden, but he referred it 

to a new subgenus Cooperellopsis.

Cooperella carpenter! Dall

Plate 14, figures 44, 47

1900. Cooperella carpenteri Dall, Wagner Free Inst. Sci. Trans.,

vol. 3, pt. 5, p. 1063. 

1900. Diplodonta yorJcensis Dall, idem, vol. 3, pt. 5, p. 1185,

pi. 43, fig. 5. 

1903. Cooperella carpenteri Dall, idem, vol. 3, pt. 6, pi. 49, fig. 8.

Shell smooth or slightly concentrically undulate, and with 

faint incremental lines; oval, nearly equilateral, the beaks mod-
120 MOLLTJSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

erately elevated; hinge delicate, hingeplate narrow, excavated; 

pallial sinus deep but only moderately high; base arcuate, ends 

rounded. Longitude 14 [12.5], altitude 11.5 [10.0], diameter 

7.50 millimeters.—Dall, 1900.

Holotype, a right valve: U. S. Nat. Mus. 153714.

Type locality: Petersburg, Va. Yorktown formation.

Both the cardinals in the right valve show a tendency 

toward a sulcated ventral margin. In the left valve 

the middle cardinal is strongly bifid, the posterior one 

simple and laminar, and the anterior cardinal usually 

simple but sometimes feebly sulcated iii the adult. The 

regularly transverse-oval and convex valves, the peculiar depression of the hinge behind the umbones, and the 

dentition characterize this small form, which in outward semblance recalls some of the smaller and more 

convex of the Diplodontas.

Dall described, under the name of Diplodonta yorkensis^ a shell apparently identical with his Cooperella 

carpenteri.

The species has been reported from a number of localities and is particularly abundant in the Yorktown 

formation in the vicinity of Suffolk.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Petersburg, Dinwiddie County; Cobham 

Wharf (upper bed) on the James River, Surry County; 12 to 

14 miles below Zuni, Blackwater River, Benns Church, Isle of 

Wight County; Sycamore on the Nottoway River and % to % 

mile above the lower Seaboard Railway bridge over the Meherrin River, Southampton County; 5% miles northwest of 

Suffolk, 2% miles northwest of Suffolk, 1% miles north of 

Suffolk, 1% miles northeast of Suffolk, 1 mile northeast of 

Suffolk, and % mile below the Suffolk waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, % mile above 

Bells Bridge, Tar River, Edgecombe County; Dogwood Landing, 

Hertford County. Duplin marl, Natural Well, Duplin County 

(Dall).

Family VENEKIDAE 

Subfamily DOSINIINAE 

Genus DO SIN IA Spopoli

1777. Dosinia Scopoli, Introductio ad Historiam naturalem, 

sistens genera Lapidum, Plantarum et Animalium, 

hactenus detecta, caracteribus essentialibus donata, 

in tribis divisa, subinde ad leges Naturae, p. 399.

Type by tautonomy: Chama dosin Adanson = Dosinia africana Hanley. Recent off the coast of Senegal and adjacent 

waters.

The outline of the paired valves of Dosinia recalls 

that of some of the discoidal lucinoids. The beaks are 

prominent and the prodissoconch is, in many species, 

unusually conspicuous. The lunule is small, sunken, 

and outlined by a deeply impressed line. In the type 

section, the escutcheon is clearly indicated both by the 

contour and by the sculpture, and it extends the length 

of the posterior dorsal margin. Tlje usual sculpture

is a flat concentric lamination, least feeble toward the 

lateral margins. The ligament is deeply inset and 

produced about half the length of the dorsal margin. 

The anterior and middle cardinals of the right valve 

are short and laminar with parallel proximate faces. 

The posterior cardinal is produced and bifid. -In the 

left valve the anterior cardinal is short and laminar 

to fit between the opposing faces of the anterior and 

middle cardinals of the right valve, the middle left 

cardinal is relatively heavy, and the posterior cardinal 

is thin and not very prominent. There is a short 

dental process by way of an anterior lateral in the 

left valve and, in the right valve, a corresponding 

socket placed near the ventral extremity of the lunule. 

The pallial line is rather distant from the smooth inner 

margins, and the sinus is almost horizontally directed 

and acutely rounded at the extremity.

The genus has been reported from the Wangaloa 

beds, Palaeocene of New Zealand, but some doubt has 

been cast by Stewart, 1930, on its occurrence at so 

early a time. In Europe the earliest records of the 

genus, according to Cossmann and Peyrot, are in the 

Aquitanian, and in the Coastal Plain deposits of this 

country the Miocene marks the first recorded appearance of the group. Marwick 50 noted that the left 

anterior lateral is merely the isolated extension of the 

anterior cardinal and does not arise independently of 

the cardinal, as in Macrocdllista and Callocardia.

Subgenus DOSINIDIA Dall

1902. Dosinidia Dall, U. S. Nat. Mus. Proc., vol. 26, p. 347.

Type by original designation: Venus concentrica Born. Recent from the Florida Keys to Rio de Janeiro.

Valves suborbicular, subcompressed, white, with a sculpture 

of concentric grooving, never lamellose; -furnished with an 

obvious periostracum;, lunule small, impressed; escutcheon 

absent; pallial sinus ample, ascending, angular in front; posterior cardinals serrate or corrugated in the nepionic young, 

smooth in the adult.

This group is confined to the tropical and warmer temperate 

seas of America.—Dall, 1902.

Dosinia (Dosinidia) acetabulum (Conrad) Conrad

Plate 11, figure 4

1832. Artemis acetabulum Conrad, Fossil shells of the Tertiary 

formations of North America, p. 20, pi. 6, fig. 1.

1834. Cytherea obovata Conrad, Acad. Nat. Sci. Philadelphia 

Jour., vol. 7, p. 132 (young shell).

1838. Cytherea obovata Conrad, Fossils of the medial Tertiary 

of the United States, p. 14, pi. 8, fig. 4.

1838. Artemis acetabulum Conrad, idem, p. 29, pi. 16, fig. 1.

1863. Dosinia acetabulum Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, p. 575.

1863. Dione obovata Conrad, idem, p. 575.

1870. Dosinia obovata Conrad, Am. Jour. Conchology, vol. 6, 

p. 77. Not D. obovata Conrad. Bush, Connecticut 

Acad. Sci. Trans., vol. 6, pt. 2, p. 477, 1885.

*° Marwick, J., New Zealand Inst. Trans., vol. 57, p. 580, 1927.
1. PELECYPODA

1894. Dosinia acetabuT\um Conrad. Whitfield, U. S. Geol. Survey Mon. 24, p. 73, pi. 13, fig. 2.

1903. Dosinia (Dosinidia) acetabulum Conrad. Ball, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1230.

1904. Dosinia acetabulum Conrad. Glenn, Maryland Geol. Survey, Miocene, p. 315, pi. 83, fig. 1; pi. 84, fig. 1.

1906. Dosinia acetabulum Conrad? Bose, Inst. geol. Mexico 

Bol. 22, p. 81, pi. 11, figs. 7, 12.

1922. Dosinia acetabulum Conrad. Olsson, Bull. Am. Paleontology, vol. 9, No. 39, p. 231, pi. 31, fig. 1.

1926. Dosinia (Dosinidia) acetabulum (Conrad). Palmer, 

Palaeontographica Americana, vol. 1, No. 5, p. 63, pi. 

19, figs. 1-3, 6-7, 9.

1932. Dosinia (Dosinidia) acetabulum (Conrad). Mansfield, 

Florida Geol. Survey Bull. 8, p. 116, pi. 24, fig. 1.

Lentiform, with numerous concentric striae, which are rather 

sharp and elevated on the anterior and posterior sides; cardinal 

fosset large, oblong, profound; with age, almost obliterating 

the posterior tooth; right valve with 3 teeth, the posterior one 

long and sulcated longitudinally; 2 anterior teeth approximate; 

left valve with 4 teeth, 3 of them distant; the anterior tooth 

somewhat pyramidal and entering a groove formed by 2 slight 

elevations in the opposite valve.

Type localities: St. Marys River and Easton, Md.; James 

River, near Smithfield, and Suffolk, Va. Upper Tertiary.— 

Conrad, 1832.

Conrad's original figures are reproduced.

Shell large, heavy, crumbly, moderately compressed, 

prolately discoidal. Umbones subcentral, flattened, 

oblique, strongly prosogyrate. Lunule impressed, cordate in the double valves, clearly delimited by an incised line. Escutcheon absent. Surface covered with 

a dark brown or rufous periostracum, which is sometimes well preserved even in the Chesapeake Miocene 

forms; surface beneath concentrically sulcated with 

somewhat irregular grooves, which are strongest and 

most regular near the dorsal magins and tend to become obsolete on the central portion of the disk. Ligament very strong; nymph elongated, roughly sickleshaped, limited dorsally by a very sharp and deep 

groove; resilial pit deep, oblong, subumbonal, often 

enlarged by decay in senile individuals so that it encroaches to a considerable extent on the posterior 

cardinal. Hinge plate broad and heavy; armature of 

right valve consisting of a simple anterior and a medial 

cardinal, their inner surfaces flattened and proximate ; 

ancl of a single obliquely elongated, rather distant, bifid, 

posterior cardinal; groove for reception of anterior 

lateral of left valve shallow; posterior lateral absent; 

hinge margin just behind posterior cardinal sharply 

pinched; armature of left valve consisting of three 

divergent cardinals, the anterior and the posterior cardinal simple and moderately elongated, the middle tooth 

broader and somewhat undulated or grooved; anterior 

lateral a small, rounded prominence placed near the 

ventral margin of the lunule. Adductor impressions 

and pallial line distinct, the area of the adherent 

mantle usually somewhat roughened, the rest of the 

interior often polished. Anterior muscle scar rudely

lenticular, the upper end, at .the ventral extremity of 

the lunule, the lower at, or a trifle above, the median 

horizontal; posterior adductor scar relatively wider 

and submedial in position. Pallial line moderately 

distant from the base. Sinus sharply ascending, 

pointed in front. Young relatively higher than the 

adults, the umbones more prominent; the concentric 

sculpture stronger and more regular, and the posterior 

cardinal transversely grooved.

Dosinia acetabulitm is one of the most widely distributed, abundant, and conspicuous bivalves in the 

east coast Miocene. The shell substance crumbles readily so that the external surface is often badly decorticated. The characters are so distinctive, however, that 

the species may be confidently determined even from 

fragments. The only coexistent representative of the 

genus—D. elegans Conrad—is a somewhat smaller, 

thinner, more compressed shell with a more pronounced 

and regular concentric sculpture.

Mrs. K. V. W. Palmer has noted an increase in the 

size of the specimens in the later formations. The 

prominence of the beaks and the strength and regularity of the concentric sculpture in juvenile specimens 

is so marked that it is not surprising they, were described by Conrad as a distinct species. Mansfield reports the rare occurrence of D. acetabulum s. s. from 

both the Ecphora and the Cancellaria zones of the 

Choctawhatchee formation, and a variety, D. acetdbulum ~blountana, from the Area zone. The mid-American shells described by Bose, 1906, and by Toula, 1909, 

may be referable to D. delicatissima Brown and Pilsbry, 

1913, from the Gatun formation.

Distribution: Virginia: Miocene, St. Marys formation?, 

Nomini Cliffs, Westmoreland County. St. Marys formation, 1 

to 2 miles below Bowlers Wharf, Essex County; 2y2 miles 

south of Farnham, Richmond County; a quarter of a mile 

below Jones Point and Urbanna, Middlesex County. Yorktown formation, 3 miles northeast of Walkerton, King and 

Queen County; Lanexa (upper bed), New Kent County; Yorktown, York County; mouth of Baileys Creek, Prince George 

County; Lieutenant Run, Petersburg, Dinwiddie County; 

Sunken Marsh Creek (upper bed), Surry County; 5 miles northeast of Smithfield, 2 miles northwest of Smithfield, 1% miles 

northwest of Smithfield, 1% miles west of Smithfield, Zuni 

(near the pumping station), 6% to 7 miles below Zuni, and 12 

to 14 miles below Zuni, Isle of Wight County; Hitchcock, 

Greensville County; 3 to 4 miles above the lower Seaboard 

Railway bridge, and % to % mile above the lower Seaboard 

Railway bridge, Southampton County; 1 mile east of Everets 

Post Office, Exit, 5% miles northwest of Suffolk, 2% miles 

northwest of Suffolk, 1% miles north of Suffolk, 1% miles north 

of Suffolk, 1 mile west of Suffolk, !*/£ miles northeast of Suffolk, 

1 mile northeast of Suffolk, and half a mile below the Suffolk 

waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, 1% to 2 miles 

abpve Branches Bridge over the Meherrin River, 1 mile above 

Branches Bridge, Branches Bridge, and 1% mile below 

Branches Bridge, Northampton County; 2% miles northwest of Murfreesboro, 1% miles above Murfreesboro, and 

near Murfreesboro, Hertford County; Halifax (at Quankey
122 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Creek, just below the county bridge) and at Palmyra Bluff, 

Halifax County; 2 miles west of Rocky Mount, % mile above 

Bells Bridge over the Tar River, % mile below Bells Bridge, 1 

mile below Bells Bridge, I 1/! miles below Bells Bridge, Shiloh 

Mills, and 1 mile below old Sparta Bridge, Edgecombe County, 

2 miles southeast of Tugwell (on Jacobs Branch), 3 miles 

south of Farmville, 3 miles southwest of Frog Level (on J. A. 

Noble's branch), 8 to 9 miles west of Greenville (on the east 

side of Pinelog* Branch), l 1/^ miles west of Greenville (on 

Schoolhouse Branch), Greenville (just east of the county 

bridge), 6 miles below Greenville, 6% miles below Greenville 

(at Tafts Landing), 8 to 9 miles southeast of Greenville, IVa 

miles west of Galloway Crossroads, 9 to 10 miles south of 

Greenville (on Fred Haddock's farm), 1 mile northwest of 

Galloway Crossroads, and % mile north of Grimesland, Pitt 

County; 2y2 miles northwest of Chocowinity, Beaufort County; 

half a mile east of Lizzie (on David Summeril's farm), Greene 

County. i

Outside distribution: Miocene, Santa Maria Tetetla, Vera 

Cruz, Mexico. Calvert formation, Atlantic City (well bore), 

N. J.; Reeds, Queen Annes County, Md,; Lyons Creek, Anne 

Arundel County, Md.; Whites Landing, Prince Georges County, 

Md.; Plum Point and Chesapeake Beach, Calvert County, 

Md. Choptank formation, Greensboro, Caroline County, 

Md.; Cordova, Peach Blossom Creek, Dover Bridge, and 

Trappe Landing, Talbot County, Md.; Sand Hill, Dorchester 

County, Md.; Governor Run, Flag Pond, and St. Leonard Creek, 

Calvert County, Md.; Turner, Jones Wharf, and Pawpaw Point, 

St. Marys County, Md. St. Marys formation, Cove Point, Calvert County, Md.; St. Marys River and Langleys Bluff, St. 

Marys County, Md.

Dosinia (Dosinidia) elegans (Conrad) Conrad

Plate 11, figure 1

1685. Pectunculus albidus, etc., Lister, pi. 288, fig. 124. 

1838. Artemis elegans Conrad, Fossils of the medial Tertiary

of the United States, p. 30. 

1844. Artemis elegans Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 1, p. 325. 

1846. Artemis elegans Conrad, Am. Jour. Sci., 2d ser., vol. 2,

p. 393. 

1850. Artemis concentrica Reeve, Conchologia iconica, vol. 6,

pi. 2, fig. 8. Not Venus concentrica Born, 1780. 

1856. Venus concentrica Gmelin. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 82, pi. 21, fig. 7. 

1858. Artemes transversus Emmons, North Carolina Geol. Survey Rept, p. 295, figs. 223, 224. 

1863. Dosinia elegans Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, p. 575. .

1863. Dosinia, intermedia Conrad, idem, p. 575. 

1889., Dosinia elegans Conrad. Dall, U. S. Nat. Mus. Bull. 37,

p. 56. 

1903. Dosinia (Dosinidia) elegans Conrad. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1231. 

1906. Dosinia elegans Conrad? Bose, Inst. geol. Mexico Bol.

22, p. 80, pi. 11, fig. 6.

1926. Dosinia (Dosinidia) elegans (Conrad). Palmer, Palae- 

• ontographica Americana, vol. 1, No. 5, p. 62, pi. 18,

figs. 3, 4, 8, 9; pi. 20, fig. 2.

This shell is nearly related to A. concentrica but is much 

larger and has the concentric lines more remote and deeply 

impressed.—Conrad, 1838.

Lentiform, regularly convex, with strongly marked, rather 

distant, impressed, concentric lines; on the posterior side these 

are closely arranged and profound, forming prominent recurved 

lines, which become acute or lamelliform toward the posterior

margin; posterior hinge margin elongated, slightly convex, oblique; lunule cordate, deeply impressed. Height 2% inches, 

length 2% inches.

Locality, Neuse River, below New Bern, N. C. Miocene.

This beautiful shell is allied to A. concentrica but is readily 

distinguished by its stronger, remoter stria, by its convexity 

of disk and its more robust anterior cardinal teeth; the posterior teeth are less oblique, forming a wider space between 

them and the anterior teeth. The posterior hinge margin is 

not so elongated, in proportion as in the concentrica.—Conrad, 

1844.

The figured right valve, U. S. Nat. Mus. 497065 from 

the Caloosahatchee Pliocene at Shell Creek, DeSoto 

County, Fla., measures 61 millimeters in height and 68 

millimeters in width.

Dosinia elegans Conrad resembles his D. acetabulum 

in the major features. It runs a little smaller than 

the latter, is somewhat more compressed and more 

uniformly rotund; the valves are thinner and less friable, the concentric sculpture is stronger and much 

more regular, and, though more elevated near the 

dorsal margins, it is always persistent and moderately 

prominent over the entire surface. The hinge is less 

heavy and rude than in D. acetabulum, and the teeth, 

though similar and similarly arranged, are more 

sharply cut. D. discus Reeve, of the post-Miocene 

faunas, is even smaller, thinner, and more compressed 

than Z>. elegans, and it has a finer, closer, less conspicuous concentric sculpture.

In all the young of this section the outline is more 

elevated, and the umbones are more prominent than 

in the adults.

D. elegans Conrad, though never so abundant, occupies in the Tertiary faunas south of the Hatteras axis 

a position analagous to that of D. acetabulum north 

of the axis.

Distribution: North Carolina: Miocene, Duplin marl, 4 miles 

north of Lumberton (on the land of Charles Rowland), Lumberton (near the bottling works), 2 miles below Lumberton, 

and 4 to 5 miles below Lumberton, Robeson County. Pliocene, 

Waccamaw formation, Walkers Bluff on the Cape Fear River, 

Bladen County; Neills Eddy Landing, 3 miles north of Cronly, 

Columbus County.

Outside distribution: Miocene, Santa Maria Tetetla, Vera 

Cruz, Mexico. Duplin marl, Sumter district, S. C. Pliocene, 

Waccamaw formation, Tillys Lake and Todds Ferry, Horry 

County, S. C. Caloosahatchee marl, half a mile above the 

Atlantic Coast Line Railroad bridge, Putnam County, Fla. 

Caloosahatchee River, Snell Creek, and Alligator Creek, Fla. 

Pleistocene, North Creek near Osprey, Manatee County, Fla.; 

Labelle, Hendry County, Fla.; Fort Lauderdale, Broward 

County, Fla.; Torch Key, Fla. Recent, Hateras to Aspinwall in 

less than 50 fathoms.

Subfamily MERETRICIITAE 

Genus MACROCALLISTA Meek

1876. Macrocallista Meek, Rept. U. S. Geol. Survey of the 

Territories, vol. 9, p. 179.

Type by monotypy: Venus gigantea Gmelin=Fen«s nimbosa 

Solander, Pliocene and Pleistocene of the Carolinas and Florida.
PART 1. PELECYPODA 123

Recent from North Carolina to the Gulf of Mexico. 

The group was isolated by Meek as a subgenus of Callista.

The solid shell, transversely ovate outline, and highly 

polished surface characterize the genus. The welldefined lunule, indistinct escutcheon, and distinct pallial sinus are group characters. The dental formula 

is similar to that of Oallocardia. There are three cardinals in each valve—the anterior and middle cardinals 

short and not very heavy, the posterior cardinal laminar and produced. The anterior left lateral is slightly 

elongated and prominent and received in a deep double 

socket of the right valve. The Recent species has a 

periostracum and a radial color pattern similar to that 

common among the Tellinas.

The group is distinguished among the venerids by 

the sleek outline, the highly polished shell, the broad 

and broadly rounded sinus almost horizontally directed'. 

Callocardia is more chalky, higher and more inflated, 

and has a less broad, obliquely directed sinus.

Macrocallista is known from the earliest Tertiary. 

It includes a considerable number of large and -attractive Tertiary and Quaternary species, inhabitants 

chiefly of the warmer seas.

Macrocallista reposta (Conrad) Dall -

Plate 19, figures 1-3, 5

1834. Cytherea reposta Conrad, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 7, p. 132. 

1834. Cytherea pandata Conrad?, idem, 1st ser., vol. 7, p. 132

(young shell). 

1858. Cytherea reposta Emmons, North Carolina Geol. Survey

Kept., p. 294, fig. 223a. Not C. reposta Emmons, 1858. 

1863. Dione reposta Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, p. 575. 

1903. Macrocallista reposta Conrad. Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1252. 

1926., Callista (Callista) reposta (Conrad). Palmer, Palaeontographica Americana, vol. 1, no. 5, p. 82, pi. 13, figs.

5, 10.

Shell large, ovate, moderately thick, and convex; beaks 

prominent; dorsal margin depressed, slightly arcuated; posterior extremity obtusely rounded; lunule large, lanceolate, 

defined by a slightly impressed line; 2 anterior cardinal teeth 

united above; posterior cardinal tooth laminar, slightly prominent; anterior tooth thick, subpyramidal. Length 5 inches, 

height 3% inches.

Locality, Suffolk, Va.—Conrad, 1834.

. Dimensions of figured specimens: Right valve (U. S. 

Nat. Mus. 325577), height 42.5 millimeters, width 62.8 

millimeters; left valve (U. S. Nat. Mus. 325575), height 

50.0 millimeters, width 85.0± millimeters.

Locality of figured specimens: Right valve, 4 to 5 

miles below Lumberton, Robeson County, N. C.; left 

valve, 2 miles below Lumberton, Robeson County, 

N. C. Duplin marl.

Macrocallista reposta (Conrad) is intermediate in 

its characters between M. cUbaria (Say) and M. nim- 

~bosa (Solander). It is relatively lower than the

former and higher than the latter; the umbones are 

between a quarter and a third of the length behind the 

anterior margin; the posterior dorsal margin, is less 

oblique than in M. aTbaria but never so nearly rectilinear as in M. nimbosa (Solander); the ligainentary 

nymph is between a third and half the length of the 

dorsal margin; the hinge armature is less rude than 

that of M. aTbaria, and less sharp than that of M. 

nimbosa. The shell is never conspicuously thickened 

within, though it is rarely so delicate as in the Recent 

form. The distribution in time and space, as well as 

the shell characters of M. reposta, are intermediate. 

M. albaria is most closely identified with the Chesapeake Miocene faunas north of the Hatteras axis; 

M. nimbosa, with the Caloosahatchee and Recent 

faunas south of the Hatteras axis; M. reposta, with 

the Duplin fauna of southern North Carolina. The 

species is abundant only along the Lumber River in 

Robeson County.

A closely related form is cited by Mansfield, 1932, 

from the Cancellaria zone of the Choctawhatch.ee 

formation of Florida.

Distribution: Virginia: Miocene, Yorktown formation, Suffolk, Nansemond County (Conrad).

North Carolina: Miocene, Yorktown formation, Colerain 

Landing (?) and % to % mile above Edenhouse Point (?), 

Bertie County. The young forms obtained at these two Yorktown localities are probably, though not certainly, referable to 

Macrocallista reposta. Duplin marl, 2% miles south of 

Clinton and 4 miles south of Clinton, Sampson County; Natural Well, ll/2 miles north of Magnolia, and the marl pits of 

Frank Wilson and W. H. Kornegay, Duplin County; 4 miles 

north of Lumberton, 2 miles below Lumberton, 4 to 5 miles 

below Lumberton, and 1% miles northeast of Fairmont (on the 

land of Andrew Jones). Pliocene, Waccamaw formation, 4 

miles south of Elizabethtown (on Hammond Creek) and Walkers Bluff (on the Cape Fear River), Bladen County; Neills 

Eddy Landing (3 miles north of Cronly), Columbus County; 

Wilmington, New Hanover County.

Subgenus COSTACALIISTA Palmer

1926. Costacallista Palmer, Palaeontographica Americana, vol. 

v 1, No. 5, pp. 73, 84.

Type by original designation: Venus erycina Linnaeus. 

Recent in the Indo-Pacific.

The subgenus is characterized by strong, flat, concentric ribbing. The outline of the shell is higher in 

proportion to its width than that of most of the 

Macrocallistas.

Macrocallista (Costacallista) emmonsi Gardner, n. sp.

Plate 19, figures 6, 9

Shell rather heavy, of moderate size and moderately 

compressed, transversely ovate in outline. Umbones 

rather low, not very conspicuous, prosogyrate, placed 

within the anterior third. Lunule narrow, lanceolate, 

outlined by an impressed line. Escutcheon suggested 

but not defined by the evanescence of the sculpture to-
124 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

ward the posterior margin. Anterior lateral margin 

broadly rounded. Posterior lateral margin rounded 

above into the gently convex dorsal margin and below 

into the ventral. Base arcuate. Surface sculptured 

with 35 to 40 deep concentric furrows, linear in the 

umbonal region, much wider toward the ventral 

margin. Ligament marginal, opisthodetic, lodged in 

a moderately deep groove, extending almost halfway 

down the dorsal slope. Hinge plate heavy; hinge of 

only right valve known. Cardinal teeth 3 in number— 

the anterior and middle cardinals moderately heavy, 

simple, cuneate, convergent beneath the tips of the 

umbones; posterior cardinal laminar, much elongated; 

anterior lateral short, conical, not far removed from 

the umbones. Adductor scars quite large and distinct, 

the anterior placed a little higher than the posterior. 

Pallial sinus very broad, obtuse, only slightly ascending, produced almost to the median vertical. Inner 

margins smooth.

Dimensions of holotype: Height 43.0 millimeters, 

width 56.5 millimeters, convexity 12.5 millimeters.

Holotype: U. S. Nat. Mus. 107834.

Type locality: Natural Well (?), Duplin County, 

N. C.

• A single valve of this large and conspicuous species 

was found among Emmons' duplicates. As nothing 

of the kind has been reported from any of the other 

numerous collections made from the Duplin County 

marls, Dall suggested that it might be a European shell 

that was, through some error, passing for an east coast 

Tertiary fossil. Curiously enough, 2 immature left 

valves have been found in the Yorktown materials, 

and, though quite young, they are apparently identical 

with the form in Emmons' collection. Further evidence of the American origin of the valve in question 

is offered by the character of the iron stains and of the 

matrix still clinging to the shell.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County (young shells).

North Carolina: Miocene, Duplin marl, Natural Well(?), 

Duplin County.

Genus CALLOCARDIA A. Adams

1864. Callocardia A. Adams, Annals and Mag. Nat. History, 

3d ser., vol. 13, p. 307.

Type by monotypy: Callocardia guttata A. Adams. Recent 

in the China Sea.

Shell ovate to subtriangular. Umbones anterior, involute. Lunule circumscribed by a faintly incised line. 

Escutcheon not delimited. Ligament external, lodged 

in a deep groove. Nymphs prominent. Exterior 

sculpture concentric. Three rather discrepant cardinals in each valve, commonly bifid or cuspid. Two 

lateral lamellae in right valve, which receive between 

them the anterior lateral tooth of the left valve. 

Pallial sinus varying widely within the limits of

the genus; angular and sharply defined to almost 

obsolete. Inner margins of valves entire.

The group is first recognized in the Eocene, since 

when it has formed a fairly conspicuous and widely 

distributed factor in the molluscan faunas of the

warmer seas.

Subgenus AGRIOPOMA Ball

1902. Agriopoma DaU, U. S. Nat. Mus. Proc., vol. 24, p. 509.

Type by monotypy: Cytherea texasiana Dall. Recent in the 

Gulf of Mexico.

The subgenus as separated by Dall is characterized 

by the heavy chalky shell, the less involute umbones, 

and especially by the deep and angular pallial sinus.

Callocardia (Agriopoma) sayana (Conrad) Dall

Plate 19, figure 33

1824. Cytherea, convex® Say, Acad. Nat. Sci. Philadelphia

Jour., 1st ser., vol. 4, p. 149, pi. 12, fig. 3. Not C. convexa Brongniart, 1822. 

1833. Cytherea sayana Conrad, Am. Jour. Sci., 1st ser., vol. 23,

p. 345. 

1838. Cytherea sayana Conrad, Fossils of the medial Tertiary

of the United States, p. 13, pi. 7, fig. 3. 

1852. Venus.' sayana, Conrad. D'Oibigny, Prodrome palSontologie, vol. 3, p. 108, No. 2011. 

1854. Meretrix sayana Conrad,. Acad. Nat. Sci. Philadelphia

Proc., vol. 7, p. 30. 

1856. Venus sayana D'Orbigny. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 83, pi. 21, fig. 9. 

1858. CytJierea (misprint for Cytherea) sayana Emmons, North

Carolina Geol. Survey Kept., p. 294, fig. 221. 

1863. Dione sayana Conrad, Acad. Nat. Sci. Philadelphia Proc.

for 1862, p. 575. 

1869. Caryatis plionema Conrad, Am. Jour. Conchology, vol. 4,

p. 278, pi. 20, fig. 3. 

1873. Callista convexa Say. Tryon, American marine conchology, p. 161. 

1894. Dione sayana Conrad. Whitfield, U. S. Geol. Survey

Mon. 24, p. 75, pi. 12, fig. 1.

1903. Callocardia (Agriopoma) sayana Conrad. Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1261, pi. 54, fig. 16.

1904. Callocardia (Agriopoma) sayana (Conrad). Glenn, Maryland Geol. Survey, Miocene, p. 313, pi. 73, figs. 13, 14.

1926. Pitaria (Pitaria) sayana (Conrad). Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 20, pi. 4, figs. 2, 

5, 12, 14, 15, 18; pi. 5, figs. 11, 15, 19, 27, 28.

Shell subcordate; elevated convex, concentrically wrinkled, 

inequilateral; posterior tooth and fosset not striated; edge not 

crenated; umbo rather prominent; lunule dilated, cordate, 

marked by a simple line.

Length liV inch[es], breadth more than lA inch[es].—Say, 

1824.

Type locality: Maryland.

Shell porcellanous, thin in the young, moderately 

heavy in adults, massive in the senile forms. Outline 

subtrigonal to ovate, inequilateral, strongly inflated in 

the umbonal region. Umbones gibbose, rather prominent, incurved, strongly prosogyrate, placed about twothirds of the way over toward the anterior margin. 

Lunule cordate, defined by an incised line. Escutcheon
PART 1. PELECYPODA 125

absent. In the young, anterior end oblique in the lunular region; in the adult, somewhat produced and convex 

jn front of the lunule; in senile individuals, inclined 

toward a uniformly steep slope from the umbones to 

the ventral margin. Posterior dorsal and lateral margins not differentiated, gently arcuate from the umbones to the base. Ventral margin much more strongly 

arched in the young than in the adult. Surface con- 

'centrically wrinkled with fine, close, discontinuous 

striae. Ligament marginal, opisthodetic; nymph sublinear, extending a little more than a third of the way 

to the base; groove behind it deep. Hinge plate heavy. 

Three cardinals developed in each valve. In the right 

valve the anterior and posterior cardinals are united beneath the tips of the beaks—the former simple and 

laminar, the latter obliquely produced and longitudinally sulcated—and the middle cardinal is an isolated 

denticle within the A formed by the union of the two 

distal teeth. Pit for reception of anterior lateral of 

left valve deep. Anterior and middle cardinals of left 

valve united to form a A-shaped tooth, the anterior arm being the thinner and more laminar; posterior cardinal slender, obliquely produced; anterior 

lateral strong, subconical. Adductor muscle impressions subequal, roughly semielliptical. Pallial line distinct, sinus short, moderately broad, both the dorsal 

and ventral margins usually ascending rather steeply.

Dimensions of figured specimen: Height 40.0 millimeters, width 45.0 millimeters.

Figured specimen: U. S. Nat. Mus. 143732.

Locality of figured specimen: Choptank River, a 

quarter to half a'mile below Barkers Landing, Talbot 

County, Md. Choptank formation.

Callocardia sayana exhibits the amount of mutation 

to be expected of a widely distributed species, but the 

confusion in the literature and collections is due to differences in age characters rather than in latitude. 

The species, though strongly inflated in the umbonal 

region, is distinctly flattened toward the ventral margin so that in the young the shell is relatively more 

convex and rotund than in the adult, the umbones are 

relatively higher and more prominent, and the base is 

more strongly arcuate. Oaryatis plionema Conrad is 

described from a senile individual. Many forms determined as Callocardia qubnasuta (Conrad) are young 

sayana in which the anterior margin is more produced 

than in the adults. They are not, however, rostrate as 

in the true C. subnasuta, and the valves are less elongated 

transversely and the umbones higher and more inflated. 

The young of the species have also been confused in 

both the reference collections and the check lists with 

the Recent Callocardia morrkuana (Linsley), a relatively lower, less trigonal species most readily separable 

from G. sayana by the deeper pallial sinus in which the 

dorsal margin is approximately horizontal rather than 

obliquely ascending. The outline of the shell is not

401033—43———9

established in the young forms, and even the sinus 

varies within narrow limits. Linsley's species is certainly not present in the adult state in the material at 

hand or in any of the available reference collections. 

The only young Callocardia not readily reconcilable 

with C. sayana (Conrad) is a single half-grown rotund 

valve from the Yorktown formation, 1 mile east of 

Lizzie, in Greene County, N. C. It is probable, however, that this is the young of an undescribed form or of 

C. castoriana rather than of C. morrhuana (Linsley).

Distribution: Virginia: Miocene, St. Marys formation, 1 to 

2 miles below Bowlers Wharf, % mile below Jones Point, Essex 

County. Yorktown formation, 3 miles northeast of Walkerton, King and Queen County. Yorktown and Bellefield, York 

County; Petersburg, Dinwiddie County; 5 miles northeast of 

Smithfleld, 2 miles northwest of Smithfieid, 1% miles west of 

Smithfleld, Zuni (near the pumping station) ? Isle of Wight 

County; % mile north of Chuckatuck, y± mile east of Everets 

Post Office, 5% miles northwest of Suffolk, 2% miles northwest 

of Suffolk, 1 mile west of Suffolk, 1% miles north of Suffolk, 

li/4 miles north of Suffolk, iy2 miles east of Suffolk, 1 mile 

northeast of Suffolk, and % mile below the Suffolk waterworks 

dam, Nansemond County. The species is exceedingly abundant 

in the environs of Suffolk.

North Carolina: Miocene, Yorktown formation, Halifax (on 

Quankey Creek, just below the county bridge) and Palmyra 

Bluff, Roanoke River, Halifax County; 2% miles northwest 

of Williamston (on Joseph Cherry's farm) and 3 miles west 

of Williamston, Martin County; 15^ miles above Bells Bridge, 

% mile above Bells Bridge, Tar River, and Shiloh Mills, Edgecombe County; 2 miles southeast of Tugwell (on Jacobs 

Branch), 2y3 miles north of Standard, 3 miles southwest of 

Frog Level (on J. A. Noble's branch), 8 to 9 miles west of 

Greenville (on the east side of Pinelog Branch), 2 miles west 

of Greenville, 1% miles west of Greenville (on Schoolhouse 

Branch), 6% miles below Greenville (at Tafts Landing), 8 to 9- 

miles southeast of Greenville, 1^ miles west of Galloway 

Crossroads, Hardees Creek (3y2 miles from its confluence 

with the Tar River), 1 mile northwest of Galloway Crossroads, 

'% mile north of Grimesland, Pitt County; 2% miles northwest of Chocowinity, Beaufort County; 1 mile west of Wilson 

(at Hominy Swamp, on the land of Frank Barnes), Wilson 

County; % mile east of Lizzie (on the land of David Summer il), Greene County; Tar Ferry, 1% miles below Tar Ferry, 

Wiccacon Creek (opposite Harrellsville), and Mount Pleasant 

Landing, Hertford County; Colerain Landing and % to % 

mile above Edenhouse Point, Bertie County. Duplin marl, 2 

miles below Lumberton, Fairmont (Ashpole), and 1% miles 

northeast of Fairmont (on the property of Andrew Jones), 

Robeson County. Pliocene, Waccamaw formation, 4 miles south 

of Elizabethtown (on Hammond Creek) and Walkers Bluff (on 

the Cape Fear River), Bladen County; Neills Eddy Landing (3 

miles north of Cronly), Columbus County; and Wilmington, 

New Hanover County.

Outside distribution: Miocene, Calvert formation, Atlantic 

City (well bore), N. J. Choptank formation, Peach Blossom 

Creek, and Choptank River, one-fourth to one-half mile below 

Barkers Landing, Talbot County, Md.; Jones Wharf, Patuxent 

River, St. Marys County, Md. St. Marys formation, Cove Point, 

Calvert County, Md.; St. Marys River, St. Marys County, Md. 

Duplin marl, Darlington, Darlington County, S. C. Pliocene, 

Waccamaw formation. Nixons and Tillys Lake, Horry County, 

S. C. Caloosahatehee marl. Kissimmee well (at a depth of 

150 feet), Osceola County, Fla.; Caloosahatchee River and Alligator Creek, Fla. Croatan sand, Slocums Creek, Craven County,
126 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

N. C. Pleistocene, Wailes Bluff near Cornfield Harbor, St. 

Marys County, Md. (Dall) ; Orient, Hillsborough County, Fla.; 

Kissimmee well (at a depth of 96 feet), Osceola County, Fla.; 

Labelle, Hendry County, Fla.

Callocardia (Agriopoma) castoriana Gardner, n. sp.

Plate 19, figures 28, 29

Shell rather large for the genus, moderately inflated, 

transversely oblong to subquadrate, inequilateral. Umbones not prominent, anterior, between two-thirds and 

three-fourths of the distance over toward the anterior 

margin; tips incurved, prosogyrate. Lunule rather 

narrow, much elongated, about three-fourths the length 

of the anterior end. Escutcheon absent; posterior submargin obscurely carinated. Anterior slope very steep, 

uniform, the dorsal and lateral margins not differentiated; posterior dorsal margin gently arcuate, lateral 

margin squarely truncate. Base line straight medially, 

strongly upcurved distally. Surface sculptured with 

crowded, discontinuous, concentric wrinkles. Ligament 

external, opisthodetic; nymph abdut half as long as the 

dorsal margin, slender, sickle-shaped, limited on the 

outer margin by a deep groove. Hinge plate wide and 

heavy. Three discrete cardinals in the right valve, 

the anterior cardinal thin and laminar, the posterior 

one heavy, longitudinally sulcate, the middle one a simple ridge with a flattened anterior surface, a little ventral to the other two cardinals; pit for reception of 

lateral of left valve small but profound; armature of 

left valve not definitely known. Adductor impressions 

subequal, semielliptical, submedial in position. Sinus 

short, broad, pointed in front, its dorsal margin approximately horizontal.

Dimensions of holotype: Height 39.0 millimeters, 

width 49.0 millimeters, convexity 14.2 millimeters.

Holotype, a right valve: U. S. Nat. Mus. 325563.

Type locality: 1 mile north of Castoria, Greene 

County, N. C. Yorktown formation.

The species is more regularly oblong or quadrate 

than any of the closely related forms. The young of 

G. morrhuana (Linsley) sometimes approach it closely 

in outline, though the adults are constantly more trigonal. Both Linsley's species and the C. say ana of 

Conrad have a cordate rather than a lanceolate lunule 

and both have the umbonal ends of the anterior and 

posterior right cardinals united to form a rather distinct U; in C. castoriana they are discrete. The hinge 

plate of the new species is more strongly angulated and 

wider anteriorly, and the space between the margin of 

the anterior lateral pit and the margin of the hinge 

plate is broader and flatter than in any of the coexistent 

species. The sinus is similar to that of C. morrhuana, 

probably its nearest of kin.

It is always unsatisfactory to describe a new species 

of a variable genus from a single valve, but in this 

case the diagnostic characters are so distinctive that

the danger of its later proving to be identical with an 

earlier species seems negligible. The single right valve 

was collected by Dr. Harvey Bassler from the vicinity 

of Castoria, in Greene County.

Distribution: North Carolina: Miocene, Yorktown formation, 

1 mile north of Castoria, Greene County.

Callocardia (Agriopoma) chioneformis Gardner, n. sp.

Plate 19, figures 7, 8

Shell heavy, moderately inflated. Outline chioneform, trigonal, inequilateral, a shallow depression in 

front of the obscure posterior carina. Umbones not 

very prominent, their tips flattened, rather strongly 

incurved and prosogyrate. Lunule wide, cordate, defined by an incised line. Escutcheon absent. Anterior 

end oblique in the lunular area, bowed outward in front 

of the lunule; posterior end a gentle and uniform arch 

from the umbones to the basal margin. Base line 

straight posteriorly or slightly sinuated by the posterior fold, strongly upcurved anteriorly. Surface 

closely and strongly wrinkled concentrically. Ligament external, nymph elongated, sublinear, narrower 

than the groove behind it. Hinge armature complex. 

Three cardinals in the right valve, the anterior and 

posterior uniting to form an open U, the anterior 

simple and laminar, the posterio.r obliquely elongated, 

slender, and sulcate longitudinally; the middle cardinal isolated, flattened on its anterior surface; pit for 

reception of lateral of left valve deep. Anterior and 

middle cardinals of left valve united beneath the tips 

of the umbones to form a A, the. anterior arm the 

more laminar; posterior cardinal oblique, very slender 

and longitudinally sulcate; anterior lateral subconical, 

prominent. Adductor impressions rather small, subequal, the anterior somewhat more elongated, median 

in position, broadly lenticular and placed not far from 

the ventral margin. Pallial line rather near the base. 

Sinus broad, obtusely pointed in front, gently ascending, but falling short of both the median horizontal 

and the vertical. /

Dimensions of holotype, a left valve: Height 26.5 

millimeters, width 31.0 millimeters, convexity 9.4 

millimeters.

Dimensions of paratype, a right valve: Height 17.5 

millimeters, width 20.5 millimeters, convexity 6.2 

millimeters.

Holotype and paratype, U. S. Nat. Mus. 325564.

Locality for both holotype and paratype: Wilmington, N. C. Waccamaw formation.

Three valves of this well-characterized species were 

collected by Dr. T. W. Stanton at Wilmington. It 

stands apart from all the coexistent Callocardia by 

reason of its chionelike outline and the posterior depression which, though shallow, persists from the umbones to the base. The lunule is wider and less 

elongated than that of C. ^sayana (Conrad), and the
PART 1. PELECYPODA 127

concentric wrinkling of the external surface somewhat 

stronger.

Distribution: North Carolina: Pliocene, Waccamaw formation, Wilmington, New Hanover County.

Subfamily VENERJNAE 

Genus CHIONE Von Miihlfeld

1811. CMone Megerle von Muhlfeld, Entwurf eines neuen System der Schalthiergehause, Magazin der Gesellschaft 

naturforschender Freunde zu Berlin, 5ter Jahrg., p. 51.

Type by subsequent designation (Gray, Zool. Soc. London 

Proc., pt. 15, p. 183, 1847) : Venus dysera Chemnitz=Venus 

cancellata Linnaeus. Recent from North Carolina to Brazil.

Ohione includes the solid trigonal venerids of medium size and convexity characterized most obviously 

by strong, often crude, concentric ribs or lamellae, with 

or without free upturned margins. A radial sculpture 

is indicated in the flutting of the free edges of the concentric lamellae and in a radial grooving, in some 

groups restricted to the ventral surfaces of the concentric ribs or, in some concentrically laminated 

groups, cancellating the disk. The lunule and escutcheon are sharply set off by both the sculpture and the 

contour of the shell. The ligament is marginal and 

deeply inset behind the beaks. There are three cardinals radiating fanlike in each valve, the medial and 

posterior cardinals in many groups grooved or bifid. 

True laterals are not developed. The muscle scars and 

the pallial line are distinct; the sinus is shallow and 

trigonal. The inner anterior and ventral margins are 

strongly crenate.

True CMone has not been certainly recognized in 

the southeastern United States below the Chickasawhay 

formation. Since the time of that formation CMone 

rapidly increased in prominence, and in the upper 

lower and in the middle Miocene of the mid-Americas 

it was ubiquitous and exceedingly abundant.

Submenus CHIONE s. s.

Type by subsequent designation (Gray, Zool. Soc. London, 

Proc., pt. 15, p. 183, 1847) : Venus dysera Chemnitz=Fewts 

cancellata Linnaeus. Recent from North Carolina to Brazil.

CMone (CMone} is characterized by a sculpture of 

regularly spaced, free-edged, concentric lamellae superimposed upon a radially lirate surface. The lamellae 

are commonly frilled in harmony with the radial lirations, and the inner margins of the valves are crenate.

Chione (Chione) cortinaria (Rogers and Rogers) Dall

Plate 19, figure 4

1837. Venous cortinaria W. B. and H. D. Rogers, Am. Philos. 

Soc. Trans., new ser., vol. 5, p. 333.

1838. Venus cortinaria, Rogers. Conrad,, Fossils of the medial 

Tertiary of the United States, p. 11, pi. 8, fig. 1.

1839. Venus cortinaria W. B. Rogers and H. D. Rogers, Am. 

Philos. Soc. Trans., new ser., vol. 6, pi. 26, fig. 7.

1863. Dione (Chamelea). cortinaria Rogers. Conrad, Acad. Nat.

Sci. Philadelphia for' 1862, p. 575. 

1903. CMone cortinaria Rogers. Dall, Wagner Free Inst. SciTrans., vol. 3, pt. 6, p. 1292. 

1926. CMone (CMone) cortinaria (Rogers). Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 142, pi. 38, figs.

4, 11,13; pi. 40, figs. 8, 37. 

1932. Chione (CMone) cortinaria (Rogers). Mansfield, Florida

Geol. Survey Bull. 8, p. 125, pi. 23, fig. 8.

Shell suflbcordate, inflated, with very regular, concentric, 

closely approximate, and very prominent imbricated ridges, 

which incline toward the beak, except the portion opposite the 

anterior, basal, and posterior margins, where they decline 

outward toward the margin; beaks moderately prominent, 

about twice as far from the anterior as the posterior end; two 

'anterior cardinal teeth, closely approximate above, second one 

of the left valve thick and subbifid; lunule wide, cordate; basal 

margin crenate within; posterior margin short, straight, and 

especially at the lunule finely crenate. Length 1 inch, height 

0.9 inch.

Locality, Williamsburg. Miocene. This beautiful shell 

rarely shows the concentric ridges perfect, from their prominence and thinness.—W. B. and H. D. Rogers, 1837.

Dimensions of figured specimen, a left valve (U. S. 

Nat. Mus. 146126) from the Yorktown formation at 

Grove Wharf, James River, Va.: Height 23.5 millimeters, width 26.5 millimeters.

Three discrete, divergent cardinals in each valve; 

the anterior cardinal of the right valve simple and 

laminar; the medial cardinal short, rather slender and 

feebly bifid; the posterior cardinal elongated parallel 

to the dorsal margin and longitudinally sulcated. The 

anterior cardinal of the left valve is simple and laminar ; the central cardinal stout and bifid; the posterior 

cardinal laminar and elongated parallel to the dorsal 

margin.

CMone cortinaria has been confused with C. cribraria 

(Conrad), though the two species are distinct when 

seen together. C. cribraria is the heavier, more convex 

shell; the concentric lamellae in C. cribraria seldom 

exceed 30, whereas in C. cortinaria they usually number between 40 and 45; the lamellae of C. cortinaria 

are lower, the flutings less conspicuous and abruptly 

evanescent near the free edge, and ordinarily they are 

so closely Oppressed dorsally that the interlamellar 

spaces are not visible as in C. cribraria; as might be 

surmised, the dentition of the inner margins of C. 

cribraria is more coarse and obvious than in the more 

finely laminated cortinaria.

CMone cortinaria (Rogers and Rogers) seems to 

have a limited distribution, though its near relative is 

both widespread and abundant.

Mansfield regarded cortinaria as one of the diagnostic fossils of zone 1 of the Yorktown formation and 

as a precursal form of cribraria. He reports cortinaria from Florida, in the Ecphora zone of the 

Choctawhatchee formation.

Distribution: Virginia: Miocene, Yorktown formation, Grove 

Wharf on the James River, Surry County; Williamsburg, 

James City County (Rogers and Rogers).
128 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

Outside distribution: Miocene, Chqctawhatchee formation, 

Jackson Bluff (southeast of Tallahassee), Leon County, Fla.

Chione (Chione) cribraria (Conrad) Ball

1843. Venus cribraria Conrad, Acad. Nat. Sci. Philadelphia

Proc., vol. 1, p. 310. 

1845. Venus cribraria Conrad, Fossils of the medial Tertiary

of the United States, p. 67, pi. 38, fig. 2. 

1858. Venus cribrari[a] Conrad. Emmons, North Carolina Geol.

Survey Rept, p. 293, fig. 218. 

1863. Dione (Chamelea) cribraria Conrad, Acad. Nat. Sci.

Philadelphia Proc. for 1862, p. 575. 

1903. Chione cribraria Conrad. Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1292. 

1926. Chione (Chione) cribraria (Conrad). Palmer, Palaeontographica Americana, vol. 1, no. 5, p. 142, pi. 38, figs.

1, 8, 9 ; pi. 39, figs. 3, 24.

Subtrigonal, slightly ventricose, with about 25 concentric 

elevated recurved lamelliform ribs, on the inferior side of which 

are elevated transverse lines; lunule cordate, laminated, suture 

profound; inner margin profoundly creunulated. Length 1% 

inch[es], height 1% [inches] nearly.

Locality: Wilmington, N. C.; Neuse River below New Bern, 

N, C.—Conrad, 1843.

, Shell rather large, heavy, and convex for the genus. 

Outline subtrigonal, inequilateral. Umbones moderately prominent, prosogyrate, about twice as far from 

the posterior as from the anterior end. Lunule short, 

cordate, defined by a deeply incised line which dissects 

the concentric lamellae. Escutcheon indicated by the 

abrupt cessation of the concentric sculpture. Anterior 

end bowed outward in front of the lunule. Posterior 

dorsal margin oblique or slightly gibbous; posterior 

lateral margin obscurely truncate. Base line strongly 

upturned anteriorly. Concentric lamellae on external 

surface 25 to 30 or even more in unusually large forms, 

elevated, rising 1 to iy2 millimeters above the surface 

of the valve and approximately at right angles to it 

except near the escutcheon, where they flare rather 

widely and are often slightly inclined toward the 

base; transverse flutings strong, sometimes evanescent 

just at the free margin, altogether absent on the lunular 

lamellae. Ligament inset; nymph linear. Hinge plate 

sinuous ventrally. Three divergent cardinals in each 

valve; the anterior and central cardinals of the right 

valve slender, simple, proximate; the posterior cardinal 

longitudinally sulcate, obliquely elongated parallel 

to the dorsal margin. Anterior cardinal of left valve 

simple, slender, and laminar, the middle cardinal stout 

and bifid, the posterior laminar, parallel to the dorsal 

margin. Adductor impressions obscure, subequal, the 

posterior slightly more rotund. Pallial sinus short, 

linguiform, the dorsal margin almost horizontal. Inner margins crenate.

Chione cribraria (Conrad) is heavier than C. cortinaria, and the crenulations of the inner margins of 

the valves are coarser and deeper; the concentric lamellae of the former are fewer and consequently less 

crowded; they are more strongly fluted transversely

and their free edges much less strongly recurved and 

less dorsally appressed. Unlike the slightly earlier 

C. cortinaria, C. cribraria is a widely distributed, 

abundantly represented species at many localities in 

the east coast Tertiary deposits.

Distribution: Virginia: Miocene, Yorktown formation 12 to 

14 miles below Zuni, Isle of Wight County; ^4 mile north of 

Chuckatuck, Nansemond County.

North Carolina: Miocene, Yorktown formation, Wilson, 

Wilson County; Colerain Landing and % to % mile above Edenhouse Point, Bertie County; Rock Landing, Craven County. 

Duplin marl, Natural Well, 1% miles north of Magnolia, and the 

marl pits of Frank Wilson and W. H. Kornegay, Duplin 

County; 2 miles below Lumberton, Robeson County. Pliocene, 

Waccamaw formation, Walkers Bluff, Bladen County; Lake 

Waccamaw, Cronly (% mile east of the factories), and Neills 

Eddy Landing (3 miles north of Cronly), Columbus County; 

Wilmington, New Hanover County.

Outside distribution: Pliocene, Waccamaw formation, Nixons 

and Tillys Lake, Horry County, S. C.

Section TIMOCLEA Brown

1827. Timoclea Thomas Brown, Illustrations of the conchology 

of Great Britain and Ireland, pi. 19, fig. 11.

Type by monotypy: Venus ovata Pennant. Recent along the 

western shores of Europe from Scandinavia southward and 

in the Mediterranean.

The section is characterized by relatively strong 

radial and relatively weak concentric sculpture.

Chione (Chione) grus (Holmes) Dall

Plate 19, figures 12, 13, 20, 21

1854. Venus parva G. B. Sowerby, Thesaurus conchyliorum,

pt. 14, p. 787, pi. 168, figs. 227, 228. Not V. parva

James Sowerby, 1829.

1858. Tapes grus Holmes, Post-Pliocene fossils of South Carolina, p. 37, pi. 7, fig. 5. 

1860. Venus trapezoidalis Kurtz, Catalogue of Recent marine

shells of North and South Carolina, p. 5. 

1867. Chione parva G. B. Sowerby. Romer, Malakozool. ,Blatter,

vol. 14, p. 60. 

1889. Ven\ws pygmaea Lamarck (part). Dall, U. S. Nat. Mus.

Bull. 37, p. 54. 

1903. Chione (Timoclea) grus Holmes. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1299. 

1926. Chione (Chione) grus (Holmes). Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 156, pi. 40, figs.

13, 18, 21. 

1932. Chione (Timoclea) grus (Holmes). Mansfield, Florida

Geol. Survey Bull, 8, p. 131, pi. 26, fig. 2.

Shell small, convex, transversely oblong, subrhomboidal, inequilateral, with 25 or 26 ribs; ribs radiating and interrupted 

by distinct overlapping zones of increase, which give the shell 

a laminated, or squamose appearance; umbones anterior; dorsal 

margin thick, rectilinear, or very slightly curved, without ribs, 

squamose; posterior margin subtruncated, anterior margin 

shorter, regularly rounded; pallial margin crenated; pallial 

sinus deep; muscular impressions large.—Holmes, 1858.

Type locality: Simmons Bluff. .Pleistocene. 

Dimensions of figured specimens, a right and a left 

valve, U. S. Nat. Mus. 325565, from the Waccamaw
PART 1. PELECYPODA 129

formation at Neills Eddy Landing on the Cape Fear 

River, N. C.: Right valve, height 6.8 millimeters, width 

9.5 millimeters, > convexity 2.6 meters. Left valve, 

height 5.0 millimeters, width 7.5 millimeters, convexity 

2.2 millimeters.

The species varies in relative proportions and the 

outline may be rhomboidal, trapezoidal, or transversely 

oblong. The lunule is short, cordate, clearly defined 

and sculptured with microscopic radials; the escutcheon is smooth or laminated by the concentric sculpture. 

The number of riblets usually exceeds 26 and those 

on the anterior half of the shell are medially bifurcated. The relative prominence of the concentric 

sculpture is a variable factor. The overlapping laminae number about 30 in a normal individual and are 

strongest on the posterior slope, where the edges are 

usually free and minutely ruffled on overriding the 

radials. The nymph is short and not very prominent; 

the dentition normal, concentrated; 3 simple, discrete 

cardinals are arranged f anlike under the umbo of each 

valve.

This small recticulate species has a meager representation in the Yorktown and Duplin formations but, 

in the Waccamaw formation particularly at Neills 

Eddy Landing, it is abundant.

Mansfield reports the species from a number of localities in his Cancellaria zone at the top of the Choctawhatchee formation in Florida. Olsson, 1922, reports a varietal form from the Gatun stage in Costa 

Rica. It is common in the Floridian Pliocene and 

occurs in the Recent shallow-water faunas from North 

Carolina to Yucatan.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; 1% miles northeast of Suffolk, 1 mile 

northeast of Suffolk, and y2 mile below the Suffolk waterworks 

dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, Rock Landing, Neuse River, Craven County. Duplin marl, Natural Well 

and 1% miles north of Magnolia, Duplin County; 2 miles below 

Lumberton, Robeson County. Pliocene, Waccamaw formation, 

Walkers Bluff on the Cape Fear River, Bladen County; Neills 

Eddy Landing (3 miles north of Cronly), Columbus County; 

Wilmington, New Hanover County.

Outside 'distribution: Miocene, Choctawhatchee formation, 

Jackson Bluff, Ochlockonee River, Leon County, Fla. Pliocene, 

Waccamaw formation, Tillys Lake, Horry County, S. C. Caloosahatchee marl, Caloosahatchee River and Shell Creek, Fla. 

Pleistocene, Simmons Bluff, S. C.; Kissimmee well (at a depth 

of 96 feet), Osceola County, Fla.; Eau Gallic, Brevard County, 

Fla.; 1 mile southwest of Daytona, Volusia County, Fla. Recent, Hatteras to Yucatan in 12 to 63 fathoms.

Section CHAMELEA Morch

1853. Chamelea Morch, Catalogus conchyliorum, quae reliquit 

D. Alphonso d'Aguirra & Gadea Comes de Yoldi, fasc. 

2, p. 23.

Type by subsequent designation (Bucquoy, Dautzenberg, and 

Dollfus, Mollusques marins du Roussillon, vol. 2, p. 355, 1893) : 

Venus gallina Linnaeus. Recent in the Mediterranean.

Chamelea is characterized by the narrow, close, concentric lamellae and the absence of radial sculpture. 

The cardinals are entire.

Chione (Chamelea) dalli Olsson

Plate 19, figures 10, 11

1914. CMone dalli Olsson, Bull. Am. Paleontology, vol. 5, No. 24,

p. 19, pi. 3, figs. 7-9. 

1926. CMone (CMone) dalli Olsson. Palmer, Paleontographica

Americana, vol. 1, No. 5, p. 162, pi. 41, figs.-l, 2, 6.

Shell ovate to triangular, slightly convex, very solid; beaks 

prominent, approximate, subacute; lunule lanceolate, defined 

by an impressed line, smooth or with lines of growth; escutcheon long and narrow, smooth; surface of shell with thick, 

flattened, concentric lamellae, fairly regularly arranged on the 

umbo, later becoming irregular and coalescing toward the basal 

margin; no radial sculpture present; hinge fairly heavy, with 

3 cardinal teeth in each valve; pallial sinus merely a small 

notch; margin minutely crenulated.

Type: Length 23, height 20, thickness 6 millimeters.

Larger shell: Length 25, height 21, thickness 6 millimeters.

On page 1290 Dall, in his Tertiary geology of Florida, volume 3, part 6, briefly describes without naming a CMone from 

Petersburg, Va., which appears to belong to this species. This 

species bears some resemblance to C. cortinaria Wagner [Rogers] but may be distinguished by its irregular concentric lamellae and the entire absence of the radial sculpture. At Claremont Wharf the species occurs in blue clays of the St. Marys 

formation, accompanied by several unusual species. Area virginiae Wagner is very common here, and a small triangular 

Olycymeris .like Pectunculus virginiae Wagner showing relationship with O. subovata, Say, of whch it is probably a 

mutation.

St. Marys formation; James River at Claremont Wharf, Va.— 

Olsson, 1914.

Shell rather small, heavy, rounded-trigonal, moderately compressed, inequilateral. Umbones low, placed 

near the anterior third, the apices acute and prosogyrate. Lunule rather small, smooth, narrow cordate, 

defined by a strongly incised line. Escutcheon moderately broad, sharply delimited by the angulation of the 

valve and the abrupt discontinuance of the concentric 

sculpture. Anterior end somewhat expanded in front 

of the lunule, rounding broadly and evenly into the 

base line. Posterior dorsal margin obliquely produced 

with a suggestion of gibbosity near the umbones. Posterior lateral margin obscurely truncate. Base line 

gently arched. Sculpture of many unequal irregular 

lamellae attached ventrally, and their dorsal margins 

somewhat fused with the surface or with each other 

posteriorly, usually free and overlapping anteriorly; 

no trace of radial sculpture discernible. Ligament external, inserted on a linear nymph. Hinge plate 

slightly sinuous. Right valve furnished with 3 discrete 

cardinals, the anterior cardinal simple and laminar, 

the middle cardinal moderately compressed, grooved 

longitudinally with a shallow sulcus; posterior cardinal 

slender, obliquely elongate, longitudinally sulcate. 

Cardinals of left valve also 3 in number, the anterior 

simple and slender, the middle cardinal cuneiform, the
130 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

posterior sublaminar, slightly convex. Adductor 

muscle impressions clearly defined, submedial, the anterior roughly semielliptical, the posterior subrotund. 

Pedal muscle impression a small dent just dorsal to the 

anterior adductor and concealed by the hinge plate. 

Inner margins very finely crenate.

Dimensions of figured topotypes (U. S. Nat. Mus. 

325529) : Eight valve, height 20.0 millimeters, width 

22.3 millimeters, convexity 5.8 millimeters. Left valve, 

height 19.5 millimeters, width 21.0 millimeters, convexity 6.4 millimeters.

Type locality: Claremont Wharf, Surry County, Va.

Chione dalli is separated from G. latilirata> (Conrad)—the only other species exhibiting low, dorsally 

appressed, concentric ribs—by the thinner shell, usually 

smaller size, and the much more numerous and less 

prominent costals; in Conrad's form, the ribs may 

number as few as 5 but never higher than 12; in C. 

dalli they may number as high as 25 and never fewer 

than 15, and they have, naturally, a concomitant difference in breadth and spacing.

Distribution: Virginia: Miocene, St. Marys formation, Claremont Wharf (lower bed) on the James River, Surry County.

Genus VENTTS Linnaeus

1758. Venus Linnaeus, Systema naturae, 10th ed., p. 684.

Type by subsequent designation (Gray, Zool. Soc. London 

Proc., pt. 15, p. 183, 1847) : Venus verrucosa Linna'eus. Recent 

along European shores from southern England to northern 

Africa and the Mediterranean.

Venus (Venus) is not represented in the Tertiary or 

Recent east coast faunas.

Submenus MERCENARIA Schumacner

1817. Mercenaria Schumacher, Essai d'un nouveau systdme des 

habitations des vers testaces, p. 135.

Type by monotypy: Venus violacea Schumacher="Fewws mercenaria Linnaeus. Gulf of St. Lawrence to Florida and the 

Gulf of Mexico.

Venus (Mercenaria) mercenaria notata Say

Plate 21, figure 10

1822. Venus notata Say, Acad. Nat. Sci. Philadelphia Jour.,

1st ser., vol. 2, p. 271. 

1858. Mercenaria, notata Say. Holmes, Post-Pleiocene fossils

of South Carolina, p. 34, pi. 6, fig. 13. 

1870. Venus notata Say. Gould, Invertebrata of Massachusetts

p. 135, fig. 446. 

1903. Venus mercenaria var. notata Say. Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1312. 

1926. Venus mercenaria notata Say. Palmer, Palaeontographica

Americana, vol. ], No. 5, p. 186, pi. 32, fig. 5.

Shell obtusely rounded before, and with a slight undulation 

on the anterior margin; disk nearly destitute of the elevated 

concentric striae, which mark the borders of the shell, and 

distinguished by rufous zigzag transverse lines; within yellowish white.

Breadth about 3 inches. 

Inhabits the coast of the United States.

Cabinet of the Academy and Philadelphia Museum, and Mr. 

Wm. Hyde's collection.—Say, 1822.

A Recent shell, U. S. Nat. Mus. 46867, from the east 

oast of Florida, has been figured. The height is 60.0 

millimeters, the width 76.0 millimeters.

The shell is less heavy and oblique than in the subgenotype, V. mercenaria s. s., the posterior dorsal slope 

is less steep, and the posterior end is consequently 

broader. The zigzag color pattern is, however, the 

only sure diagnostic, and as this is rarely preserved 

in the fossil forms the subspecific determinations are 

exceedingly dubious.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; Claremont Wharf (upper bed) on the 

James River, Surry County.

Outside distribution: Pleistocene, Simmons Bluff, S. C. Recent, Massachusetts to Georgia in less than 50 fathoms.

Venus (Mercenaria) campechiensis rileyi Conrad

1838. Venus rileyi Conrad, Fossils of the medial Tertiary of 

the United States, p. 9, pi. 6, fig. 1.

1856. Venus rileyi Conrad. Tuomey and Holmes, Pleiocene 

fossils of South Carolina, p. 78, pi. 21, fig. 8.

1858. Venus rileyi Emmons, North Carolina Geol. Survey Rept., 

p. 292.

1863. Mercenaria rileyi Conrad, Acad. Nat. Sci. Philadelphia 

Proc. for 1862, vol. 14, p. 574.

1903. Venus tridacnoides var. rileyi Conrad. Dall, Wagner 

Free Inst. Sci. Trans., vol. 3, pt. 6, p. 1311.

1904 Venus rileyi Conrad. Glenn, Maryland Geol. Survey, Miocene, p. 304, pi. 76, figs. 4, 5.

1926. Venus tridacnoides (Lamarck) (part). Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 191, pi. 33, 

figs. 1, 3.

1932. Venous tridacnoides rileyi Conrad. Mansfield, Florida 

Geol. Survey Bull. 8, p. 133, pi. 28, fig. 3.

Shell obliquely ovate, slightly ventricose, thick, very inequilateral ; disks with small, crowded, reflected, concentric ribs; 

anterior side narrowed; umbo very oblique, prominent; posterior margin arcuate; inner margin deeply crenulated.

Locality, Yorktown, Va.

This shell has probably been confounded with V. tridacnoides, 

but it is much thinner, not undulate on the disk, and the 

cardinal teeth are much less robust. Its narrowed and compressed anterior side will distinguish it from the other fossil 

species, and its ribs from the recent V. mercenaria. Young 

shells are compressed or plano-convex. The disks are generally 

worn, showing the radiating striae common to all these large 

fossil species when the surface becomes decomposed. It is 

named in compliment to my scientific friend, Dr. William 

Riley, of Baltimore.—Conrad, 1838.

Shell only moderately heavy, transversely oval or 

ovate to subquadrate in outline. Umbones rather low 

and not very prominent, their tips acute and prossogyrate, situated as a rule within the anterior third. 

Lunule narrow, cordate, varying with the outline of 

the shell, delimited posteriorly by a sharply, incised 

line which dissects the concentric lamellae; lunular 

sculpture (similar (to that of the disk. Escutcheon 

slightly narrower and more laminar in the right valve
PART 1. PELECYPODA 131

than in the left valve, elongate-cuneate or scimitarshaped; defined by both the angulation of the valve 

and the partial obsolescence of the surface sculpture, 

which, however, is manifested at least by vigorous 

incrementals. Anterior end bowed out in front of the 

lunule, rounding broadly and evenly into the base; 

posterior dorsal margin subrectilinear, oblique, or 

slightly gibbous. Posterior lateral margin broadly 

rounded, obtusely pointed or obscurely truncated. 

Base line approximately horizontal or gently arcuate. 

Sculpture of thin, sharp, concentric lamellae, erect 

or with a dorsal inclination, so crowded in perfect 

individuals that the surface of the shell is visible only 

near the umbones, uniform in strength from the lunule 

to the anterior margin of the escutcheon; concentric 

lamellae eroded in the great majority of individuals, 

revealing a pronounced subsurficial radial sculpture. 

Ligament powerful, opisthodetic, seated on a correspondingly heavy nymph. Dentition normal in pattern but heavy. Adductor muscle scars very large, 

deeply impressed. Pedal scar, a dent beneath the anterior cardinal. Pallial line distinct, the sinus short, 

acutely angular. Inner surface thickened over the area 

of the adherent mantel. Inner margins finely crenate.

Venus (M ercenaria) campechiensis rileyi is inconstant in sculpture, the outline of the lunule and escutcheon, and the outline and equipment of the hinge plate. 

These characters vary not only concomitantly but independently as well. The group in each formation, however, presents a similar general effect. This is most 

strikingly exemplified in the Waccamaw where it is so 

distinctive that, given an intergrading series of some 

twenty-odd forms with typical end members, one can 

place the group vertically, and often horizontally, with 

a fair degree of assurance.

The most serviceable characters in isolating the subspecies rileyi have proved to be the oval, ovate, or 

subquadrate outline, which is never conspicuously trigonal or circular; the moderately light shells; the 

rather compressed valves; and the low, anterior 

umbones.

In the Yorktown formation, from which Conrad's 

type was derived, the subspecies rileyi is relatively 

small and heavy and is ovate to subquadrate in outline. 

Along the Nansemond River, in the environs of Suffolk, 

a larger, lighter, often posteriorly produced form is 

very common. Measurements of valves typical of this 

locality are as follows: Height 107.0 millimeters, 86.5 

millimeters; width 144.0 millimeters, 116.5 millimeters; 

convexity 28.5 millimeters, 27.0 millimeters. The subspecies rileyi is exceedingly abundant on the Chowan 

River, and pairs of valves with the crowded, concentric, 

lamellar sculpture perfectly preserved are far from 

rare. Dimensions of typical individuals are as follows : Height 67.0 millimeters, 68.5. millimeters; width

95.0 millimeters, 83.5 millimeters; convexity 24.0 millimeters, 24.5 millimeters.

The James River race as a whole, and particularly 

the Smithfield forms, are small, relatively thin, and 

ovate in outline, with the concentric lamellae usually 

eroded except toward the basal margin. Measurements 

of typical individuals from the James River are as 

follows: Height 65.0 millimeters, 60.0 millimeters; 

width 90.0 millimeters, 73.0 millimeters; convexity 22.0 

millimeters, 18.0 millimeters. Along the Meherrin and 

Nottoway Rivers the subspecies is characteristically 

represented by large, notably thin, and elevated shells, 

often posteriorly produced and obtusely pointed. The 

dimensions of two perfect individuals are as follows: 

Height 91.0 millimeters, 93.0 millimeters; width 127.0 

millimeters, 123.0 millimeters; diameter 53.0 millimeters, 51.5 millimeters. These dimensions suggest the 

Suffolk race, but the shells are larger and relatively 

higher, with a more oblique posterior dorsal margin 

and a lateral margin more often bluntly pointed rather 

than subtruncate. There is a tendency toward a similar, though less extreme development in the representatives from the Roanoke and Tar Rivers in Edgecombe 

County, although along the lower course of the Tar 

River in Pitt County, where the form is unusually abundant, the valves are, generally, smaller and relatively 

heavier, with a more persistent sculpture. In all the 

Yorktown localities in southern Virginia and north of 

the Hatteras axis in North Carolina the transition to 

the moderately large and moderately heavy, subtrigonal 

F. campechiensis s. s. is very easy and frequently accomplished. South of the Hatteras axis, however, the group 

assumes quite a different aspect. F. campechiensis is 

represented in the Waccamaw by the ponderous subspecies carolinensis Conrad, but even in the Duplin the 

representatives of the subspecies rileyi have taken on the 

peculiarities of the group, and the small, thin, transversely oval, peripheral forms exhibit the close, crowded, 

often dorsally inclined concentric lamellae, which is 

characteristic of their massive kindred, a significant 

fact in the consideration of the probable line of descent 

of carolinensis.

Mansfield records the species from the Ecphora zone 

of the Choctawhatchee formation.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; mouth of Baileys Creek, Prince George 

County; Lieutenant Run near Petersburg, Dinwiddie County; 

Grove Wharf and Schmidts Bluff (8% miles below Claremont 

Wharf), Surry County; 1% miles northeast of Smithfield, % 

mile northeast of Smithfield, Fergusons Wharf, Benns Church, 

1^ miles above Zuni, and 8 to 8^ miles below Zuni on the 

Blackwater River, Isle of Wight County; Hitchcock, Greensville County; Sycamore on the Nottoway River, % to % mile 

below Sycamore, 3 to 4 miles above the lower Seaboard Railway 

bridge, % to % mile above the lower Seaboard Railway bridge, 

and jMaddelys Bluff on the Meherrin River, Southampton 

County; Exit, 5 miles northeast of Suffolk, 1% miles northwest 

of Suffolk, 1% miles north of Suffolk, 1% miles northeast of
132 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA A.ND NORTH CAROLINA

Suffolk, 1 mile northeast of Suffolk, y2 mile below the Suffolk 

waterworks dam, and the drainage ditch just east of Jericho 

ditch, Nansemond County.

North Carolina: Miocene, Yorktown formation, 2% miles 

northwest of Murfreesboro (at Watsons Mill on Kirbys Creek), 

Tar Ferry on Wiccacon Creek (opposite Harrellsville), 1% 

miles below Tar Ferry, 3 to 4 miles below Tar Ferry, and 

Dogwood Landing on the Chowan River, Hertford County; Colerain Landing, Mount Gould Landing, and % to % mile above 

EdenhouFe Point on the Chowan River, Bertie County; Halifax 

(on Mr. Durham's property), % mile above the Atlantic Coast 

Line Railroad bridge, and at Palmyra Bluff, Halifax County; 

Hamilton Bluff, 2 miles southeast of Hamilton Bluff, 4 miles 

northwest of Williamston, and 2% miles northwest of Williamston (on Joseph Cherry's property), Martin County; 1 mile below 

Bells Bridge, Shiloh Mills, Tarboro (at L. E. Fountain's farm), 

and 1 mile below old Sparta Bridge over the Tar River, Edgecombe County; 2 miles below Toddy Station, 4 miles east of 

Farmville (on the east side of Pinelog Branch), 2% miles 

north of Standard, 8 to 9 miles west of Greenville, 2 miles west 

of Greenville, iy2 miles west of Greenville (on Schoolhouse 

Branch), Pitt County; Greenville (just east of the county 

bridge), 6 miles below Greenville, 6% miles below Greenville 

(at Tafts Landing), 9 to 10 miles south of Greenville, 1 mile 

northwest of Galloway Crossroads, and % mile north of Grimesland, Pitt County; 2% miles northwest of Chocowinity and 

1% miles northeast of Chocowinity, Beaufort County; 1 mile 

north of Castoria, % mile east of Lizzie (on David Summeril's 

property), and 4 miles east of Lizzie (in Dog Swamp, on the 

property of O. W. Frizzelle), Greene County; Rock Landing on 

the Neuse River, Craven County. Duplin marl, 3 miles south 

of Clinton (on Gum Chimney Branch, on the property of 

Hugh Moore), Sampson County; Natural Well and 1% miles 

north of Magnolia, Duplin County; Lumberton (near the 

bottling works) and 1% miles northeast of Fairmont (on the 

property of Andrew Jones), Robeson County. Pliocene, Waccamaw formation, 4 miles south of Clarkton, Bladen County; 

Donahues Landing, 48 miles above Wilmington, 4 miles south 

of Elizabeth town (on Hammond Creek, on the property of Mrs. 

Clark), Bladen County; Walkers Bluff on the Cape Fear 

River, Bladen County; Lake Waccamaw and Neills Eddy Landing (3 miles north of Cronly), Columbus County; Wilmington 

(at the city rock quarry), New Hanover County.

Venus (Mercenaria) campechiensis carolinensis Conrad

Plate 20, figures 1, 2

1875. Mercenaria carolinensis Conrad. Kerr, North Carolina

Geol. Survey Rept, vol. 1, App. A, p. 20. 

1903. Venus campechiensis Gmelin (part). Dall, Wagner Free

Inst. Sci. Trans., vol. 3, pt. 6, p. 1315. 

1926. Venus ea-mpccMensis carolinensis (Conrad). Palmer,

Palaeontographica Americana, vol. 1, No. 5, p. 190. 

1932. Venus campechiensis carolinensis (Conrad). Mansfield,

Florida Geol. Survey Bull. 8, p. 132, pi. 28, fig. 4.

Shell subtriangular, elongated, very inequilateral, slightly 

ventricose, disk with coarse, flattened, uneven, imbricated ridges 

on the middle and posterior side, the lines disposed to be ramose ; on the anterior side and posterior slope they are sharp, 

prominent, rugose, imbricated lines; lunule large, cordate. 

Length 5 inches, height 4 inches.

'Locality, Cape Fear River.—Conrad, 1875. Waccamaw formation.

Dimensions of figured specimen, a left valve, U. S. 

Nat. Mus. 325573, from the Waccamaw formation at 

Walkers Bluff on the Cape Fear Eiver, N. C.: Height

119.0 millimeters, width 153.0 millimeters, convexity 

45.0 millimeters.

Shell ovate to subtriangular, very large, and ponderous. Posterior dorsal margin often slightly gibbous. 

Lunule cordate, delimited by a deep linear groove, laminated. Escutcheon less sharply defined, narrower and 

more strongly laminated in the right valve than in the 

left. Surface sculptured with thin, sharp lamellae that 

number 2 or 3 to the millimeter, except on the umbones; 

often dorsally appressed on the disk, most elevated 

near the lunule. Ligamental and hinge areas extremely 

heavy but otherwise normal for the species. Adductor 

scars indicative of the powerful muscles necessary to. 

control so weighty a shell. Pallial line and sinus distinct, often thrown into prominence by the thickening 

of the interior of the shell over the area of the adherent 

mantle.

The measurements of 3 characteristic valves are as 

follows: Height 140.0 millimeters, 120.0 millimeters, 

130.0 millimeters; width 182.0 millimeters, 150.0 millimeters, 160.0 millimeters; and convexity 50.0 millmeters, 43.0 millimeters, 41.0 millimeters.

Venus (Mercenaria) campechiensis carolinensis Conrad is second in bulk only to V. campechiensis tridacnoides Lamarck. Although not approaching the latter in the degree of deformity, some individuals in the 

collection exhibit not only a decided interior thickening 

but the base line is rippled by a'radial undulation similar to that of tridacnoides. By a decrease in size, 

weight, relative altitude, and prominence of the umbones V. carolinensis merges gradually into the ubiquitous V. rileyi, its probable ancestor.

Mansfield reports the species from the Oancellaria 

zone of the Choctawhatchee formation.

Distribution: North Carolina: Pliocene, Waccamaw formation, 4 miles south of Elizabethtown (on Hammond Creek) 

and at Walkers Bluff (on the Cape Fear River), Bladen 

County; Neills Eddy Landing (3 miles north of Cronly), 

Columbus County.

Venus (Mercenaria) campechiensis tridacnoides (Lamarck) 

Conrad

Plate 21, figure 11

1685. —— Lister, Historiae sive Synopsis Methodicae Conchyliorum, pi. 499, fig. 53. 

1818. Cyprina tridacnoides Lamarck, Histoire naturelle des

animaux sans vertebres, vol. 5, p. 558. 

1824. Venus deformis Say, Acad. Nat. Sci. Philadelphia. Jour.,

1st ser., vol. 4, p. 148, pi. 12, figs. 2, 2a. 

1838. Venus tridacnoides Conrad, Fossils of the medial Tertiary

of the United States, p. 10, pi. 7, fig. 2. 

1856. Venus tridacnoides Conrad. Tuomey and Holmes, Pleiocene fossils of South Carolina, p. 85, pi. 22, fig. 1. 

1858. Venus tridacnoides Conrad. Emmons, North Carolina

Geol. Survey Rept., p. 292. 

1858. Venus difformis Say. Emmons, idem. 

1863. Mercenaria tridacnoides Lamarck. Conrad, Acad. Nat.

Sci. Philadelphia Proc. for 1862, p. 574. 

1867. Heroenaria percrassa Conrad, Am. Jour. Conchology, vol.

3, p. 13.
PART 1. PELECYPODA 133

1869. Mercenaria percrassa Conrad, idem, vol. 4, p. 278, pi. 19,

fig. 1. 

1903. Venus tridacnoides Lamarck. Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1310. 

1926. Venus tridacnoides (Lamarck) (part). Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 191, pi. 33, fig. 6.

C. testa transversim ovata, corrugata; striis verticalibus; 

limbo superiore undatim plicato.

Mon cabinet. List. Conch, t. 499. f. 53.

Habite . . . Fossile d'ltalie. Largeur, 11 centimetres. Coquille singulie"re; grande, plissee, en son limbe, comme dans 

les tridacnes, ayant dans les interstices de ses sillons des stries 

verticales.—Lamarck, 1818.

Type locality not known but certainly not "Italie."

Shell subcordate, with transverse wrinkles, which are distant 

and regular on the umbones, and much crowded on the basal 

half; several very obtuse longitudinal undulations, of which 

that on the middle is more profound; basal margin deeply 

undulated in compliance with the undulations of the disk; 

within crenate on the edge; anterior margin flattened and 

simply wrinkled.

Length nearly 5, breadth 6 inches. Smallest specimen, 3.7 

inches long and 4% inches wide.

This extraordinary shell has so unusual an appearance, that 

I should almost have been disposed to regard a single specimen 

as a monstrosity. The examination of several individuals 

proves that the species varies somewhat in form and in the 

locality of the undulations.—Say, 1824.

The deformity of this shell is sometimes so great 

that a valve 107.5 millimeters in width will have a 

maximum thickness of 33.70 millimeters. The outline 

is variable, as Say has noted, and the undulations are 

inconstant in both their strength and their position. 

The lunule varies with the outline; the escutcheon is 

moderately broad; the nymph is heavy and the groove 

deep enough to seat a ligament adequate to hold the 

massive valves; the rugose area is broadly lenticular 

and strongly marked. The hinge plate and dentition 

are robust; the anterior cardinal of the right valve is 

simple, the middle and posterior cardinals are bifid; 

the anterior and middle cardinals of the left valve are 

bifid, the posterior is simple and somewhat laminar. 

The muscle impressions and pallial characters are 

thrown into prominence by the thickening of the shell 

over the area of the adherent mantle. The adductor 

scars are very large, the anterior adductor semielliptical, the posterior, subcircular. The pallial line is moderately distant from the hinge margin; the sinus is short 

and triangular. The crenulations of the inner margins 

are rather finer than one might expect in such ponderous 

valves.

Neither the abnormal thickening nor the undulations 

are developed in the young forms, which are indistinguishable from the young of Venus campechiensis 

rileyi, and the adults exhibit varying degree of thickness and undulation from the normal subspecific form 

to the incongruously ponderous individuals that have 

attracted the attention of conchologists since the time 

of the prebinomial Lister. The fact that the normal

and abnormal types are coexistent at many localities 

would suggest a pathologic state that is due to some 

organism. A general condition such as the mechanical 

or chemical constitution of the sea water or the features 

of the food supply would be fairly constant at a given 

locality and would probably affect all individuals alike.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County; mouth of Baileys Creek, Prince George 

County; Petersburg, Dinwiddie County; Fergusons Wharf, 

Grove Wharf on the James River, Surry County; Benns Church, 

iy2 miles above Zuni and 12 to 14 miles above Zuni on the 

Blackwater River, Isle of Wight County; Sycamore, % to % 

mile below Sycamore on the Nottoway River, % to> i% mile 

above the lower Seaboard Railway bridge, and at Maddelys 

Bluff on the Meherrin River, Southampton County.

North Carolina: Miocene, Yorktown formation, 1% to 2 miles 

above Branches Bridge, Northampton County; 1% miles 

above Murfreesboro on the Meherrin River, Hertford County; 

Halifax (on Mr. Durham's farm % mile above the Atlantic 

Coast Line Railroad bridge), Halifax County; 4 miles northwest of Williamston, Martin County; 15% miles above Bells 

Bridge, and % mile above Bells Bridge over the Tar River, 

Edgecombe County; 3 miles west of Greenville, Pitt County. •

Venus (Mercenaria) berryi Gardner, n. sp.

Plate 21, figures 1-6

Shell small, rather light, moderately inflated, ovate 

to subtrigonal externally, ovate to subquadrate internally. Umbones rather plump but not very prominent; the apices acute and prosogyrate, a distance of 

about one-third the width back from the anterior margin. Lunule rather narrow, conspicuously cordate, 

outlined posteriorly by a deeply impressed groove that 

dissects the sculpture. Escutcheon lanceolate, wider, 

and less strongly laminated in the left valve than 

in the right. Anterior margin bowed out in front 

of the lunule. Posterior dorsal margin gently declining or slightly gibbous. Lateral margin broadly 

rounded, as a rule. Ventral margin gently arcuate, 

more strongly upcurved in front than behind. Sculpture unusually variable in detail but uniform in general 

aspect; concentric lamellae 45 to 65 in number, erect 

on the posterior and, particularly, on the anterior margin, the free edges frequently crenulated; laminae 

closely appressed dorsally on the medial portion of the 

disk, and often fused either with the surface or with 

one another; sculpture on the disk thus developed into 

low, flat, unequal areas, formed by the fusion of 2 to 8 

lamellae, separated from one another by narrow channels that occasionally bear 1 to 2 linear lirations. 

Eadial sculpture discernible only on eroded surfaces. 

Ligament area moderately wide, approximately half 

the posterior dorsal margin in length; ligament 

mounted on rather vigorous nymphs, the outer margin 

inset in a deep groove that obliquely undercuts the 

dorsal margin of the valve. Rugose area narrow, elongate. Three discrete cardinals in each valve, spreading 

fanlike from beneath the tips of the umbones. An-
134 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

terior cardinal of right valve compressed; middle cardinal robust, feebly bifid; posterior cardinal more compressed and elongate and more deeply sulcate longitudinally. Anterior cardinal of left valve moderately 

compressed-cuneiform but more elevated than either of 

the other 2, feebly depressed medially; middle cardinal 

robust, rudely sulcate, but distinctly less elevated than 

the tooth in front of it; posterior cardinal exceedingly 

thin and elongate, partially fused with the rugose area 

behind it; lateral margin in right valve grooved for the 

reception of the beveled edge of the escutcheon of the 

left valve. Adductor muscle scars of moderate size, 

submedial in position, distinct but not strikingly prominent. Pallial line moderately distant from the ventral 

margin. Pallial sinus short, not attaining the median 

vertical, its dorsal margin approximately horizontal, 

the terminal angle not far from 45°. Inner margins 

finely and evenly crenate.

Dimensions of holotype (paired valves) : Height 57.0 

millimeters, width 62.5 millimeters, diameter 37.6 millimeters. Dimensions of adult paratype, a right valve: 

Height 46.5 millimeters, width 54.0 millimeters, convexity 10.6 millimeters. Dimensions of adolescent paratype, height 8.0 millimeters, width 8.5 millimeters.

Holotype (paired valves) and adult paratype, a right 

valve: U. S. Nat. Mus. 325574.

Adolescent paratype, a right valve: U. S. Nat. Mus. 

325576.

Locality of types: Holotype and adult paratype, 2% 

to 3 miles below Bowlers Wharf, Essex County, Va. 

St. Marys formation. Adolescent paratype, 1 to 2 

miles below Bowlers Wharf, Essex County, Va. St. 

Marys formation.

Venus (Mercenaria) berryi stands so far apart from 

the described Tertiary species of the middle Atlantic 

coast that its affinities are somewhat in doubt. The 

more regularly sculptured forms suggest a subdued 

type of V. ducatelli Conrad, on which the concentric 

lamellae are developed in greater numbers and less 

conspicuously than in the normal form. The phenomenon of the fusion of the lamellae, is however, quite 

unknown in Conrad's form, and when the fusion tends 

toward the somewhat strongly marked obsolescence of 

the entire surface sculpture on the disk, the species 

approaches some of the manifestations of V. mercenaria 

Linneaus. The general contour of the shell, however, 

and the distribution are much more suggestive of V. 

ducatelli Conrad than of V. mercenaries,.

The young shells are rotund little valves sculptured 

with equisize, equispaced, relatively distant, concentric 

lamellae, which are uniform in strength and character 

over the entire surface of the shell. So individual is 

the species in the young stage that it recalls on first 

examination an unusually rotund Chione.

I have the pleasure of naming the species in honor 

of Dr. E. W. Berry, the former dean of the Undergraduate School, Johns Hopkins University, who, though 

best known as an administrator and as a notable contributor to knowledge of the Tertiary floras, has done 

much to advance the knowledge of the faunas as well.

Distribution: Virginia: Miocene, St. Marys formation,, 1 to 2 

miles below Bowlers Wharf and 2% to 3 miles below Bowlers 

Wharf on the Rappahannock River, Essex County.

Venus (Mercenaria) plena inflata Dall

Plate 21, figure 9

1903. Venus plena var. inflata Dall, Wagner Free Inst. Sci. 

Trans., vol. 3, pt. 6, p. 1310.

A variety which may be called inflata is more trigonal and 

measures 60 millimeters long, 55 [51.0] millimeters high, and 

36 [20.5] millimeters in diameter [convexity of single valve]. 

It is from Bellefield, York River, Va.—Dall, 1903.

Holotype, a right valve: U. S. Nat. Mus. No. 163419.

Type locality: Bellefield, York River, Va. Yorktown formation.

Shell heavy, elevated, trigonal, inflated in the umbonal region. Umbones gibbous, involute, prosogyrate, 

fully three-fourths of the way over toward the anterior 

margin. Lunule broadly cordate, laminated, bounded 

by a deeply incised line that dissects the concentric 

sculpture. Escutcheon rather obscure, feebly laminar. 

Anterior margin convex in front of the lunule. Posterior dorsal margin obliquely produced or somewhat 

gibbous; posterior lateral margin subtruncate. Base 

line straight, upcurved anteriorly. Surface covered 

with thick, heavy lamellae, closely crowded together. 

Ligamentary nymph rather slender; groove behind it 

deep. Dentition normal, three discrete cardinals in 

each valve, fanlike in their arrangement; anterior 

cardinal in both valves simple; middle cardinal in both 

valves bifid; posterior cardinal bifid in the right, 

simple in the left; rugose area rather narrow. Adductor impressions distinct; semielliptical. Pallial 

line rather distant from the margin. Sinus short, 

triangular.

The subspecies is heterodox only in the outline.

Distribution: Virginia: Miocene, Yorktown formation, Bellefield, York County.

Venus (Mercenaria) plena nucea Dall

Plate 21, figures 7, 8

> 

1903. Venus plena var. nucea Dall, Wagner Free Inst. Sci.

Trans., vol. 3, pt. 6, p. 1310.

Another form which I found mixed with the type at the same 

locality [Bellefield, York River, Va.] and at first thought might 

be distinct, is rounded, subtruncate behind, very thick for its 

size, the surface slightly undulate and with the lamellation 

obsolete. It may take the name of variety nucea. It measures: Length [width] 33, height 29 [30.0], and diameter 16 

millimeters [convexity 11.0 millimeters].—Dall, 1903.

Holotype, a right valve: U. S. Nat. MUS. 163418. 

Shell heavy, rude, rounded, roughly quadrate or trigonal, inflated in the umbonal region, often flattening
PART 1. PELECYPODA 135

rather abruptly toward the umbones. Umbones 

strongly anterior, sometimes not more than a fifth of 

the way back from the anterior margin, involute, 

prosogyrate. Lunule cordate or oblong, sharply defined, laminated. Escutcheon lanceolate, laminar, 

rather obscure. Anterior end very short; slightly 

arcuate in front of the lunule, in some individuals 

sloping uniformly from the umbones to the base at 

an angle not exceeding 10° or 12° off the vertical. Posterior dorsal margin oblique or somewhat gibbous, 

broadly truncated laterally. Base line straight or 

gently arcuate. Hinge characters normal for the 

species. Muscle impressions and pallial line emphasized by a thickening of the shell over the surface of 

attachment of the mantle.

The subspecies is remarkable for its small, rude, 

stunted valves, which strongly suggest a pathologic 

condition.

Distribution: Virginia: Miocene, Yorktown formation, Bellefield, York County.

Subfamily GEMMINAE

This group includes small species of Veneridae, which are 

characterized by viviparity and carry the young for a considerable period, like Sphaeri\um, within the perivisceral chamber. They have, as a rule, purple and white coloration, if 

any, and a smooth or concentrically striated surface. They 

live in sand or mud in moderate depths of water on both 

coasts of North America and have not been identified from 

any other region.—Dall,51 1903.

Genus GEMMA Deshayes

1853. Gemma, Deshayes, Catalogue of the Conchifera of the 

British Museum, pt. 1, p. 112.

Type by tautonomy and monotypy: Venus gemma Totten. 

Recent from Labrador to North Carolina.

Gemma includes a group of small venerids roughly 

resembling in outline a 60° segment of a circle. A 

large, rather obscurely defined lunule is developed but 

no escutcheon. The surface is concentrically wrinkled, 

and the inner margins of the valves are radially 

crenate. The hinge armature is restricted to three cardinals in each valve, unequal in size and diverging 

fanlike from beneath the tips of the umbones. The 

pallial sinus is short and steeply ascending.

The genus has been an inconspicuous element in the 

faunas of the east coast and Gulf since the middle 

Eocene. There is no record o.f it in either the Tertiary 

or the Recent European seas.

Gemma magna Dall

1903. Gemma magna Dall, Wagner Free Inst. Sci. Trans., vol. 

3, pt. 6, p. 1330, pi. 57, fig 4.

1926. Gemma magna Dall. Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 206, pi. 43, fig. 22.

61 Dall, W. H., Wagner Free Inst. Sci. Trans., vol. 3, pt. 4, p. 1329, 1903.

1932. Gemma magna Dall. Mansfield, Florida State Geol. Survey Bull. 8, p. 134, pi. 27, figs. 1, 2.

Shell trigonal, moderately convex, the anterior end slightly 

shorter, rounded; the posterior end longer, more pointed; 

beaks high, pointed; lunule [s]lightly flattened, bounded by 

an incised line often feeble, lanceolate, about half as long as 

the anterior dorsal slope; escutcheon not defined; surface sculptured with numerous regular, even, concentric sulci, with 

wider smooth interspaces; hinge normal, well developed, especially the long lateral laminae, the cardinals entire; basal 

margin crenulate, pallial sinus small, angular. Length 7, height 

6, dimeter 4 millimeters.

G. magna+attains a larger size than any of the later representatives of the genus. It resembles G. var. purpurea of the 

recent fauna in its sculpture, but relatively is much less 

inflated.—Dall, 1903.

The measured and figured specimen, which may be 

considered the lectotype, is U. S. Nat. Mus. 115174. It 

is a right valve. Mounted on the same card with it o

and bearing the same Museum number is a second right 

valve and two left valves.

Type locality: Natural Well, Duplin County, N. C. 

Duplin formation.

Gemma magna Dall in the broader sense is a protean 

species and one of the most prolific of the smaller bivalves. Were it not for the wealth of material, the 

differences between the peripheral members would be 

regarded as specific; but with a complete series of 

intergrading individuals it is impossible to establish 

anything more than subspecific variations. The Yorktown formation has two common subspecies, one 

notably small, high, and moderately heavy, with a 

rather delicate hinge (subspecies virginiana) ; the other 

characterized by a relatively large, rather thin, compressed, and rounded, but usually inequilateral shell 

with umbones of little prominence and a moderately 

robust hinge (subspecies majorina). In the Duplin, 

the species is fairly large, though smaller, relatively 

more strongly inflated, higher and more angular than 

the subspecies majorina, but lower, more inequilateral, 

and decidedly larger than the subspecies virginiana. 

Gemma magna is, however, more unstable in the Duplin 

than in any of the other formations, and it exhibits, 

even at the type locality (the Natural Well), a bewildering range in. outline, degree of compression, and 

sculpture. The individual selected as the type is high, 

trigonal, approximately equilateral, and closely and 

regularly sulcated concentrically. From this characteristic type, the form may merge into a lower, less 

angular, more compressed, a~nd more inequilateral 

phase. Variations in the strength of the sculpture bear 

no relation, apparently, to the variations in outline. 

The prodissoconch and frequently the entire umbonal 

region are destitute of sculpture, and occasionally, 

though more rarely than in the succeeding Waccamaw, 

the entire valve is smooth (subspecies insulcata) • G. 

magna s.s. reaches distinctly greater dimensions in 

Robeson County than in Duplin County and is usually
136 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

more inequilateral in the former. The Waccamaw 

race is less differentiated than the Yorktown race and 

is hardly more than a collection of miniatures of Duplin forms. Both the high trigonal, inflated, equilateral 

type and the lower, ovate, more compressed, inequilateral type are present together with the intergrading 

individuals. The tendency toward a smooth surface 

is much stronger than in Miocene forms, a rather perverse phase in the development of the species, since the 

juvenile valve is smooth, and, with the rise in the stratigraphic column, one might reasonably expect an evolution toward a constantly and regularly sulcated type 

rather than away from it.

Distribution: North Carolina: Miocene, Yorktown formation, 

3 miles south of Farmville, Pitt County; Colerain Landing on 

the Chowan River, Bertie County. Duplin marl, Natural Well, 

1% miles north of Magnolia, and W. H. Kornegay's marl pit, 

Duplin County; 4 miles north of Lumberton (on the Berry 

Godwin plantation), 2 miles below Lumberton, 4 to 5 miles 

below Lumberton, and 1% miles northeast of Fairmont (on 

the property of Andrew Jones), Robeson County. Pliocene, 

Waccamaw formation, 4 miles south of Elizabeth town (on Hammond Creek, on the property of Mrs. Clark) and Walkers 

Bluff (on the Cape Fear River), Bladen County; Neills Eddy 

Landing (3 miles north of Cronly), and Lake Waccamaw, 

Columbus County; Wilmington (at the city rock quarry), New 

Handver County.

Outside distribution: Pliocene, Waccamaw formation, Todds 

Ferry on the Waccamaw River, Horry County, S. C. Caloosahatchee marl, Nashua, Putnam County, Fla.; Caloosahatchee 

River, Alligator Creek, and Shell Creek, Fla.

Gemma magna virginiana Dall

Plate 19, figures 15-18, 25, 26

1903. Gemma magna var. virginiana Dall, Wagner Free Inst.

Sci. Trans., vol. 3, pt. 6, p. 1330. 

1926. Gemma magna virginiana Dall. Palmer, Palaeontographica Americana, vol. 1, No. 5, p. 206.

Shell smaller, shorter, more delicate. Length 3.8, height 3.6, 

diameter 1.6 millimeters.

From the Miocene of Yorktown, Va., in the middle portion 

of the series; Harris.

This form is the earliest Gemma now known, and if I felt 

sure that it was adult I should separate it specifically from G. 

magna, which appears in the uppermost Miocene just before 

the opening of the Pliocene epoch. It closely resembles the 

young of the G. magna, and perhaps larger specimens may 

hereafter turn up.—Dall, 1903.

Dimensions of figured cotypes: Eight valves, height 

3.4 millimeters, width 3.5 millimeters; height 3.2 millimeters, width 3.3 millimeters. Left valves, height 3.7 

millimeters, width 4.1 millimeters; height 3.0 millimeters, width 3.2 millimeters.

Dimensions of figured topotype, a left valve: Height 

3.3 millimeters, width 3.6 millimeters.

Cotypes, 2 right and 3 left valves: U. S. Nat. Mus. 

144633.

Topotypes, a right and a left valve: U. S- Nat. Mus. 

325571.

Type locality: Yorktown, Va. Yorktown formation.

The most constant difference between the subspecies 

and G. magna s.s is the smaller size and less robust 

hinge of the former. The greater degree of inflation 

and the higher and more nearly equilateral outline 

separate virginiana from the coexistent subspecies majorina. G. magna virginiana follows the tendency that 

seems to be general among the Tertiary Gemmas of 

presenting an unsculptured as well as a sculptured 

phase. All the other characters remain constant, however, and the transition between the smooth form and 

the evenly sulcated type is freely demonstrated in the 

material at hand.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County (both smooth and sulcate races) ; 1% miles 

southeast of Reids Ferry (both smooth and sulcate races); 1 

mile north of Suffolk (sulcate race only), Nansemond County.

North Carolina: Miocene, Yorktown formation, half a mile 

above Bells Bridge over the Tar River, Edgecombe County; 

Tar Ferry on Wiccacon Creek (opposite Harrellsville), Hertford County; Colerain Landing (smooth type only) and % to 

% mile above Edenhouse Point on the Chowan River (smooth 

type only), Bertie County; Rock Landing on the Neuse River 

(both smooth and sulcate types), Craven County.

Gemma magna majorina Gardner, n. subsp.

Plate 19, figures 19, 27

Shell large for both the genus and the species; moderately compressed. Outline ovate to subtrigonal, inequilateral. Umbones flattened, inconspicuous, erect 

or slightly prosogyrate, often rather bulbous at their 

tips, placed a little in front of the median horizontal. 

Lunule indicated merely by the cessation of the concentric sculpture. Escutcheon not defined. Dorsal 

and lateral margins not differentiated; anterior slope 

shorter and consequently steeper than the posterior. 

Base line evenly and rather strongly arched. Surface 

normally sculptured with 30 to 40 fine, regular, continuous, concentric striae; occasional resting stages 

present. Ligament external, opisthodetic; nymph 

short, sublinear; groove behind it narrow. Hinge concentrated; middle cardinal of right valve stout, triangular ; cardinal behind it more slender; that in front 

of it a thin lamina often worn or broken away; anterior 

and middle cardinals in left valve cuneate, the anterior, 

the more slender and produced, separated from the 

medial cardinal by a deep, triangular, subumbonal 

socket; posterior cardinal of left valve thin and laminar; posterior dorsal margin of right valve and anterior dorsal margin of left valve sulcated to receive 

the slightly modified corresponding margins of the 

opposite valves. Adductor impressions small, the anterior impression somewhat oblong and submedial, the 

posterior relatively broader and a little lower. Pallial 

line obscure, rather distant. Pallial sinus short, linguiform, and sharply ascending; inner margins usually 

crenate.

Dimensions of cotypes: Eight valve, height 5.6 millimeters, width 6.6 millimeters, convexity 1.4 millimeters.
PART 1. PELECYPODA 137

Left valve, height 6.6 millimeters, width 7.3 millimeters, convexity 1.5 milliireters.

Cotypes, the right and left valves of different indididuals: U. S. Nat. Mus. 325566.

Type locality: One mile east of Lizzie, Greene 

County, N. C. Yorktown formation.

Gemma magna majorina is notably larger than G. 

magnet s. s., more compressed, less trigonal, with more 

rounded margins, a relatively thinner shell, and a less 

robust hinge.

Distribution: Virginia: Miocene, Yorktown formation, 1 mile 

northeast of Suffolk, and % mile below the Suffolk waterworks, Nansemond County.

North Carolina: Miocene, Yorktown formation, Halifax and 

Palmyra Bluff on the Roanoke River, Halifax County; Hamilton Bluff, a % mile below Hamilton Landing, 3 miles west of 

Williamston, and 2% miles northwest of Williamston (on the 

property of Joseph Cherry), Martin County; 3 miles west of 

Rocky Mount, Bdgecombe County; 2 miles below Toddy Station, 2 miles southeast of Tugwell (on Jacobs Branch), 3 

miles southwest of Frog Level (on J. A. Noble's branch), 8 to 

9 miles southeast of Greenville, 9 to 10 miles south of Greenville, and 2 miles east of Grifton (on J. F. Brooks' property), 

Pitt County; 2% miles northwest of Chocowinity, Beaufort 

County; 2 miles southwest of Maple Cypress (on the Neuse 

River), Craven County; 1 mile west of Wilson (in Hominy 

Swamp, on the property of Frank Barnes) (smooth race as 

well as sulcated), Wilson County; 1 mile north of Castoria 

and 1 mile east of Lizzie (both smooth and sulcate races), 

Greene -County; Tar Ferry and 1% miles below Tar Ferry 

on Wiccacon Creek (opposite Harrellsville), Hertford County; 

% to % mile above Edenhouse Point on the Chowan River, 

Bertie County.

Gemma magna insulcata Gardner, n. subsp. 

Plate 19, figures 14, 22

Shell trigonal or approximately so. Valves evenly 

inflated. Apical angle not far from 60°; posterior 

margin often a little more produced and pointed than 

the anterior; base line arcuate, more strongly upcurved, as a rule, before than behind. Umbones 

inconspicuous, the apices obtuse, directed toward one another. Lunule and escutcheon not differentiated. Surface smooth except for incrementals, which may assume 

a certain regularity toward the ventral margin. Ligament opisthodetic, mounted upon a sublinear nymph. 

Three cardinals in the right valve but only one of 

them at all obvious; anterior cardinal very thin and 

laminar, often broken away; posterior cardinal only a 

little less slender but decidedly more elongate; middle 

cardinal stout and trigonal; three cardinals of left 

valve less discrepant in strength than those of right; 

anterior cardinal much compressed and rather short; 

middle cardinal narrowly cuneiform, posteriorly directed ; posterior cardinal merely a thin lamina, which 

is rarely preserved in perfection; posterior dorsal margin of right valve and anterior dorsal margin of left 

valve sulcated to receive the slightly modified corresponding margins of the opposite valve. Adductor impressions obscure but apparently normal for the species. 

Pallial sinus short, very sharply ascending, somewhat 

linguif orm. Inner margins finely crenate.

Dimensions: Holotype, height 4.5 millimeters, width 

5.2 millimeters, convexity 1.5 millimeters; paratype, 

height 3.4 millimeters, width 4.1 millimeters.

Holotype, a right valve, U. S. Nat. Mus. 325567; 

paratype, a left valve, U. S. Nat. Mus. 325570.

Type localities: Holotype, Neills Eddy Landing, Columbus County, N. C.; paratype, Walkers Bluff, Bladen 

County, N. C. Waccamaw formation.

The diagnostic character for the separation of G. 

magna insulcata from the G. magna s.s. is the absence 

of a well-defined concentric sculpture. In many of 

the forms the sculpture is not assumed until the individual has attained a width of three millimeters, so 

that adults with smooth uinbonal areas are quite common. It is rather unexpected that the tendency toward 

a smooth shell, apparently a reversion to type, should 

be most strongly marked in the Waccamaw (Pliocene).

Distribution: North Carolina: Miocene, Duplin marl, 2 miles 

below Lumberton and 4 to 5 miles below Lumberton, Robeson 

County. Pliocene, Waccamaw formation, Walkers Bluff on 

the Cape Fear River, Bladen County; Cronly (% mile east of 

the factories) and Neills Eddy Landing (3 miles of Cronly). 

Columbus County.

Gemma cravenensis Gardner, n. sp.

Plate 19, figures 23, 24

Shell rather large for the genus, thin, compressed, 

suboval in outline, .slightly inequilateral. Anterior 

dorsal margin a little shorter than the posterior, and 

consequently a little less gently sloping; lateral margins 

broadly and evenly rounded; base line straight medially, upcurved distally. Umbones low, rather flat, and 

not at all conspicuous; apices obtuse and turned toward 

each other. Lunule merely suggested, not defined. 

Escutcheon absent. Surface smooth or feebly sulcated 

toward the margins by the growth lines. Ligament 

external, opisthodetic, seated on a very narrow, but 

rather robust nymph. Hinge normal but expanding 

with the dorsal margins, and less concentrated than in 

the more trigonal races. Armature in the right valve 

consisting of a very thin laminar anterior cardinal, a 

sturdy, triangular, subumbonal middle cardinal, and a 

compressed and obliquely produced posterior cardinal. 

Three cardinals present in the left valve as well, the 

anterior cardinal only a little less robust and a little 

more compressed than the middle, and separated from 

it by the deep, subumbonal socket; the posterior cardinal thin, laminar, oblique, but not produced; right 

anterior and left posterior dorsal margins feebly sulcated and the opposing margins beveled. Muscle impressions small, slightly below the median horizontal, 

the anterior renif orm, and more regular in outline than 

the posterior. Pallial line rather distant. Pallial
138 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

sinus broad and shallow. Inner margins faintly 

crenate.

Dimensions of holotype: Height 3.7 millimeters, 

width 4.6 millimeters, convexity 0.9 millimeters.

Holotype, the right and left valves of a single individual : U. S. Nat. Mus. 325569.

Type locality: Rock Landing on the Neuse Eiver, 

Craven County. Yorktowii formation.

Gemma cravenensis is most closely allied to G. magna 

majorina. It is, however, much thinner, more compressed, and more oval, with a fanlike divergence of 

the cardinals that isolates it readily even among the 

protean representatives of G. magna.

Distribution: North Carolina: Miocene, Yorktown formation, 

Rock Landing on the Neuse River, Craven County.

Gemma verdevilla Gardner, n. sp.

Plate 19, figures 31, 32

Shell minute, but rather heavy, subcircular, subequilateral. Posterior end more evenly arcuate than the 

anterior, which is obscurely truncate dorsally. Base 

line evenly rounded. Umbones, rather inflated but not 

conspicuous. Apices obtuse, facing one another. 

Lunule faintly suggested but not defined. Escutcheon 

absent. Surface very feebly and somewhat irregularly 

sculptured by the incrementals. Ligament external, 

opisthodetic, seated on linear nymphs. Hinge delicate, 

concentrated. Right valve armed with a very thin, 

laminar, anterior cardinal; a robust, cuneiform, middle 

cardinal; and a compressed, obliquely produced, posterior cardinal. Left valve with subequal anterior, 

and middle cardinals, the anterior a little the more 

compressed, the two separated by a deep, triangular, 

subumbonal socket; posterior cardinal imperfect in the 

type but oblique and probably much compressed. 

Feeble lateral ridges developed on the anterior margin 

of the right valve and the posterior margin of the left, 

with corresponding grooves in the posterior margin of 

the right valve and the anterior margin of the left. 

Muscle impressions small, a little below the median 

horizontal, the anterior minutely reinform and more 

regular in outline than the posterior. Pallial line 

rather distant. Sinus broad and very shallow. Inner 

margins faintly radiate but not crenate.

Dimensions of holotype: Height 2.6 millimeters, 

width 2.6 millimeters, diameter 1.3 millimeters.

Holotype, the right and left valves of a single individual : U. S. Nat. Mus. 325568.

Type locality: Eight to 9 miles southeast of Greenville, Pitt County, N. C. Yorktowii formation.

Gemma verdevilla is smaller than any of the associated Gemmas, is more inflated, and is more rotund in 

outline, with less angular umbones and a broader, more 

shallow, pallial sinus. The species is known only from 

the two valves, which belong apparently to the same 

individual.

Distribution: North Carolina: Miocene, Yorktown formation, 

8 to 9 miles southeast of Greenville, Pitt County.

Superfamily MYACEA

Family MYACIDAE 

Genus MYA Linnaeus

1758. Mya Linnaeus, Systema naturae, 10th ed., p. 670.

Type by subsequent designation (Schumacher, Bssai d'un 

nouveau systeme des habitations des vers testacSs, p. 116) : 

Mya truncata Linnaeus. Recent in the estuaries and coastal 

waters of the British Isles. Found in the fossil state as early 

as the Coralline Crag.

Shell oblong or rhomboidal, only slightly inequivalve, gaping at both extremities. Outer surface incrementally wrinkled. Umbones low, proximate. 

Ligament attached to a projecting chondrophore in the 

left valve and, in the right valve, to an inverted ligament pit directly beneath the umbo. No development 

of either a cardinal or a lateral dentition. Adductor 

scars subequal. Pallial sinus deep.

Davies 52 has given an interesting series of diagrammatic sections showing the change in the position of 

the resilium and resilifer from the strongly inequivalve 

Corbulas, in which the attachment areas of the right 

and left valves are diagonally opposed, to that of Mya, 

in which the valves are approximately equal in size but 

the chondrophore of the left valve projects beneath the 

resilial pit of the right, so that the opposing attachment 

faces are almost directly one above the other.

The genus is known from the Tertiary to the present 

day. The Recent species are largely confined to the 

northern hemisphere and, though few in number, are 

prolific in individuals.

Mya arenaria Linnaeus /

Plate 22, figure 8

1758. Mya, arenaria, Linnaeus, Systema naturae, 10th ed., p. 670. 

1822. Mya acuta Say, Acad. Nat. Sci. Philadelphia Jour., 1st

ser., vol. 2, p. 313. 

1822. Mya mercenaria Say, idem.

1841. Mya, arenaria Linnaeus. Gould, Invertebrata of Massachusetts, p. 40. 

1845. Mya, corpulenta Conrad, Fossils of the medial Tertiary

of the United States, p. 68, pi. 39, fig. 1. 

1858. Mya arenaria Linnaeus. Holmes, Post-Pleiocene fossils

of South Carolina, p. 55, pi. 8, fig: 15. 

1863. Mya corpulenta Conrad, Acad. Nat. Sci. Philadelphia

Proc. for 1862, p. 572. 

1889. Mya arenaria Linnaeus. Dall, U. S. Nat. Mus. Bull. 37,

p. 70, pi. 49, fig 9; pi 55, fig 2; pi. 69, fig. 2. 

1898. Mya. arenaria Linnaeus. Dall, Wagner Free Inst. Sci.

Trans. vol. 3, pt. 4, p. 857. 

1906. Mya arenaria Linnaeus. Clark, Maryland Geol. Survey,

Pliocene and Pleistocene, p. 194, pi. 53, figs. 5, 6; pi.

54, figs. 1-4.

52 Davies, A. M., Tertiary faunas, vol. 1, p. 203, fig. 282, 1935.
PART 1. PELECYPODA 139

1908. Mya arenaria Linnaeus. Rogers, Shell book, p. 324, pi. 

facing 323, fig. 7.

M. testa ovata postice rotundata, cardinis dente antrorsum 

porrecto rotundato denticuloque lateral!.

Habitat in O. Europae septentrionalis sub arena, foraminibus 

duobus detegenda.—Linnaeus, 1758.

Mya, arenaria varies in the outline of the posterior 

portion of the valves from the evenly rounded forms 

to the distinctly angular. This, the soft-shell or sand 

clam of the fish market, is a common inhabitant of the 

northern Atlantic and Arctic waters on both American 

and European shores. Though most abundant on the 

gravelly mud flats of the New England coast, it is found 

as far south as South Carolina and as far north as 

Greenland, and though originally introduced accidentally with seed oysters, it is now well established in the 

waters of San Francisco Bay.

dark's figure of a left valve from the Pleistocene 

at Wailes Bluff, Md., is reproduced. The species, 

though not abundant, may be found frequently in the 

red Miocene cliffs along the York River, while the 

waters at the base of the cliffs serve as a home for its 

living representatives.

Distribution: Virginia: Miocene, Yorktown formation, Yorktown, York County.

North Carolina: Pliocene, Waccamaw formation, Lake Waccamaw and Neills Eddy Landing, Columbus County.

Outside distribution: Pleistocene, Point Shirley and Sankaty 

Head, Mass.; Wailes Bluff and Cornfield Harbor, St. Marys 

County, Md.; Simmons Bluff and Abbapoola, S. C. Recent, 

Arctic Ocean to North Carolina and possibly to Miami, Fla., 

in water up to 40 fathoms; also on Scandinavian coasts in 

the low-tide area.

Family CORBULIDAE 

Genus CORBULA Bruguiere

1797. Corbula Bruguiere, Tableau encyclopedique et me"thodique 

des trois regnes de la nature, vers, coquilles, mollusques, 

et polipiers, pi. 230, figs, la-c; 3a-c; 4a-d; 5a-c; 6a-b. 

(Figures only, no text.)

1799. Corbula, Lamarck, Prodrome d'une nouvelle classification 

des coquilles, Soc. histoire nat. Paris m£m., p. 89. 

(No species cited.)

1801. Corbula Lamarck, Systeme des animaux sans vertebres, 

p. 137.

1811. Aloidls Megerle von Miihlfeld, Entwurf eines neuen 'System der Schalthiergehause, Magazin der Gesellschaft 

naturforschende Freunde, 5ter Jahrg., p. 67.

Type by monotypy: Corbula guineensis Von Miihlfeld=C'orbula sulcata Lamarck.

Type by subsequent designation (Schmidt, C. F., Versuch 

uber die beste Einricht, etc., pp. 57, 177, Gotha, 1818: Corbula 

sulcata Lamarck. Recent off the coast of Senegal.

In the earlier reports, I have followed the type designation of Children, 1822, Corbula nucleus Lamarck= 

G. gibba (Olivi). G. sulcata Lamarck served as the 

type of the subgenus Aloidis. If Schmidt's designation be accepted, and there seems to be no adequate

reason for rejecting it, Aloidis Von Miihlfeld becomes 

an exact synonym of Corbula s. s.

Topotypes in the Academy of Natural Sciences, Philadelphia, are between 15 and 20 millimeters high and 

25 millimeters wide. The posterior keel is very sharp 

and is defined anteriorly by a deep sulcus, which per-> 

sists from the nepionic shell to the margin. Both 

valves are coarsely rugose, the sculpture on the right 

valve being heavier than on the left. Radial sculpture 

is absent on the conch. The tips of the umbones are 

conspicuously capped by the nepionic valves, which 

differ from the adult to a remarkable degree. They 

are nearly equivalve, compressed, acutely rostrate, posteriorly, and similarly sculptured with concentric rugae, 

which strengthen toward the ventral margin. There 

are no east American shells sufficiently close to the large 

coarse Senegalese shell to suggest the representation of 

the 0. sulcata group in east American waters either in 

Tertiary or in Recent times.

Subgenus CARYOCORBULA Gardner

1926. Caryocorbula Gardner, Nautilus, vol. 40, p. 46.

Cuneocorbula Dall and authors, not Cuneocorbula Cossmann, 1886.

Type by original designation: Corbula alabamiensis Isaac Lea. 

Claiborne (Eocene) of the east coast and Gulf region from 

South Carolina to the Rio Grande.

Shell small or of moderate dimensions; acutely keeled 

posteriorly. Slightly inequivalve; right valve a little 

larger and a little higher relatively than the left. 

Both valves concentrically rugose, the sculpture on the 

right valve in some species stronger and more regular 

than on the left; a microscopically fine radial lineation developed in some of the later species, particularly 

on the posterior keel. Ligament, dental, muscle, and 

sinal characters similar to those of Corbula, s.s.

Caryocorbula includes most of the American species 

formerly assigned to Cuneocorbula. Caryocorbula differs from the Paris Basin group in that the shell is 

less trigonal, not so produced posteriorly, usually heavier, unirostrate rather than birostrate, and more 

strongly sculptured. Caryocorbula is abundantly represented in the Tertiary and Pleistocene deposits of the 

east coast and Gulf and in the Recent east American 

waters.

Corbula (Caryocorbula) conradi Gardner, n. sp.

Plate 23, figures 27, 28

Shell inequivalve, right valve commonly overlapping 

the left, inequilateral, moderately heavy and convex, 

strongly rostrate. Umbones low, the left umbo a little 

the higher. Base line of right valve arcuate, slightly 

sinuous posteriorly; that of the left slightly oblique, 

ascending a little in front of the rostrum. Sculpture 

of fine, mostly continuous and equidistant, concentric
140 MOLLUSCA FROM MIOCENE AND LOWER PLIOCENE OF VIRGINIA AND NORTH CAROLINA

lirae, which persist across the keel with little change 

in character; submicroscopic, radial striations also visible in well-preserved specimens, more distinct as a rule 

on the le|t valve. Ligament internal, seated on a process of the posterior dorsal margin of the left valve. 

Cardinal socket deep. Cardinal tooth stout, recurved, 

placed beneath the right umbo; resilial pit behind it 

moderately excavated. Muscle impressions and-pallial 

line indistinct.

Dimensions of holotype (paired valves) : Height 6.7 

millimeters, width 11.0 millimeters, diameter 4.7 millimeters.

Holotype, paired valves: U. S. Nat. Mus. 325605.

Type locality: 15l/2 miles above Bells Bridge on 

the Tar Eiver, Edgecombe County, S. C. Yorktown 

formation. (

The species suggests Corbula inaequalis Say in the 

general outline of the valves. It is not, however, so 

large or so heavy as the latter. The most conspicuous 

difference is in the concentric sculpture, which is closer, 

finer, and more regular than that of G. inaequalis and 

approaches that of C. cuneata Say, a relatively low 

species that is characterized by the straight base line 

of the right valve. The new species differs, furthermore, from both G. inaequalis Say and C. cuneata Say 

in the possession of a delicate radial sculpture that is 

less pronounced than, but similar in character to, that 

exhibited by C. barrattiana C. B. Adams and C. swiftiana C. B. Adams. G. dominicensis Gabb is not relatively so high and is larger.

G. conradi is quite widely distributed and fairly 

abundant in the Miocene and Pliocene of Virginia and 

North Carolina, where it has doubtless been confused 

with its notoriously variable congener, G. inaequalis, 

and possibly with the much less common G. cuneata.

Distribution: Virginia: Miocene, St. Marys formation?, Nomini Cliffs, Westmoreland County. St. Marys formation, 2% 

miles south of Farnham, Richmond County; Urbanna, Middlesex County. Yorktown formation, 4 miles northwest of Walkerton and 3 miles northeast of Walkerton, King and Queen 

County; Yorktown, York County; Petersburg, Dinwiddie 

County; % mile northeast of Smithfleld, 12 to 14 miles below Zuni, Isle of Wight County; Sycamore, and % to % mile 

below Sycamore, Southampton County; 1% miles southeast of 

Reids Ferry, 1% miles north of Suffolk, 1 mile northeast of 

Suffolk, 1 mile west of Suffolk, and y2 mile below the Suffolk 

waterworks dam, Nansemond County.

North Carolina: Miocene, Yorktown formation, Watsons Mill 

on Kirbys Creek, 2% miles northwest of Murfreesboro, Tar 

Ferry, and 3 to 4 miles below Tar Ferry, Wiccacon Creek 

(opposite Harrellsville), Hertford County; Halifax, Halifax 

County; 2% miles northwest of Williamston (on Joseph 

Cherry's farm), Martin County; Swift Creek, 15% miles above 

Bells Bridge, % mile above Bells Bridge, Tar River, and 

at Shiloh Mills, Edgecombe County; 7 miles southeast of Wilson, Wilson County; 1 mile north of Castoria, % mile east of 

Lizzie (on David Summeril's farm), and 4 miles east of Lizzie 

(in Dog Swamp, on O. W. Frizzelle's farm), Greene County; 

1% miles northeast of Farmville, 3 miles south of Farmville,

2 miles west of Greenville, and 6% miles below Greenville (at 

Tafts Landing), Pitt County; Rock Landing, Craven County.

Corbula (Caryocorbula) conradi retusa Gardner, n. subsp.

Plate 23, figures 33, 34

Shell rather small, subtrigonal, inequivalve. Inequilateral, rostrate posteriorly. Umbones flattened, incurved, prosogyrate. Base line of right valve strongly 

arcuate; that of left slightly oblique. Concentric 

sculpture of rather coarse lirae, 20 to 25 in the type; 

approximately equisize and equidistant; on the anterior slope becoming discontinuous toward the medial 

portion of the valve, and on the posterior portion and 

keel often obsolete; radial striae faintly visible over the 

entire shell. Hinge normal.

Dimensions of holotype: Height 5.0 millimeters, 

width 7.7 millimeters, diameter 3.3 millimeters.

Holotype, paired valves: U. S. Nat. Mus. 325604.

Type locality: Half to three-quarters of a mile below 

Edenhouse Point, Bertie County, N. C. Yorktown 

fo.rmation.

The subspecies retusa is a little smaller and noticeably higher than Corbula conradi s. s. The most constant difference, however, is in the concentric sculpture, 

which, instead of being approximately uniform over 

the entire valve as in G. conradi s. s., becomes irregular 

medially and evanescent posteriorly. These characters 

are shared by G. inaequalis Say, and the resemblance 

between the subspecies retusa and the young of the 

coexistent inaequalis is often disconcerting. The delicate radial sculpture will serve to determine the form, 

if the individuals are fresh. If this diagnostic feature 

has been lost through erosion, there is an aspect of 

regularity and clean definition of sculpture on the anterior part of the shell that will serve to separate a 

series, though it may be of little value in the determination of single individuals. The type was taken from 

the Yorktown sands of the Chowan Eiver, half to 

three-quarters of a mile above Edenhouse Point. The 

subspecies is quite common at a number of localities 

along the Chowan, but it is rare in the Duplin.

Distribution: Virginia: Miocene, Yorktown formation, Exit, 

Nansemond County.

North Carolina: Miocene, Yorktown formation, 7 miles southeast of Wilson, Wilson County; 6% miles below Greenville (at 

Tafts Landing), Pitt County; 2 miles southwest of Maple 

Cypress, Craven County; Dogwood Landing and Mount Pleasant Landing, Hertford County; Colerain Landing and half to 

three-quarters of a mile above Edenhouse Point, Bertie County. 

Duplin marl, Natural Well and 1% miles above Magnolia, 

Duplin County.

Corbula (Caryocorbula?) scutata Gardner, n. sp.

Plate 23, figures 26, 30-32

Shell heavy, subtriangular to subtrapezoidal; both 

right and left valves strongly convex, the former a
PLATES 1-23

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401033—43——11
PLATE 1

FIGURES 1-2. Nucula proxima Say (p. 19).

1. Exterior of right valve; height 4.0 millimeters; width 4.5 millimeters. (After Clark.)

2. Interior of same valve. (After Clark.) 

FIGURE 3. Nucula diaphana H. C. Lea (p. 20). Interior of left valve (Acad. Nat. Sci. Philadelphia 1591); height 2.5 millimeters;

width 3.1 millimeters. 

FIGURES 4-5. Nucula proxima Say (p. 19).

4. Interior of left valve; height 3.9 millimeters; width 4.7 millimeters. (After Clark.)

5. Exterior of same valve. (After Clark.) 

FIGURE 6. Glycymeris tumulus (Conrad) (p. 27). Interior of left valve (U. S. Nat. Mus. 325483) from Nomini Cliffs, Westmoreland

County, Va.; height 44.5 millimeters; width 44.7 millimeters. 

FIGURES 7-8. Brachidontes (Ischadium) recurvus (Rafinesque) (p. 29).

7. Exterior of right valve; height 18.0 millimeters; width 30.0 millimeters. (After Clark.)

8. Interior of left valve; height 13.3 millimeters; width 22.5 millimeters. (After Clark.) 

FIGURE 9. Nucula diaphana H. C. Lea (p. 20). Exterior of left valve (Acad. Nat. Sci. Philadelphia 1591); height 2.1 millimeters;

width, 2.7 millimeters. 

FIGURE 10. Yoldia laevis (Say) (p. 21). Exterior of right valve and interior of left valve; height 13.0 ± millimeters width 26.0 ±

millimeters. (After Say.) 

FIGURE 11. Glycymeris laevis (Tuomey and Holmes) (p. 26). Exterior of left, and interior, hinge and teeth of right valve; height

30.0 ± millimeters; width 31.0 ± millimeters. (After Tuomey and Holmes.) 

FIGURES 12-15. Glycymeris tumulus (Conrad) (p. 27).

12. Exterior of left valve (U. S. Nat. Mus. 325483) from Nomini Cliffs, Westmoreland County, Va.; height 44.5 millimeters; 

width 44.7 millimeters.

13. Exterior of juvenile (U. S. Nat. Mus. 325483); height 7.8 millimeters; width 7.3 millimeters.

14. Interior of same valve figured to show early dentition.

15. Profile of closed valves from front (U. S. Nat. Mus. 325483); greatest convexity 27.0 millimeters. 

FIGURES 16-21. Glycymeris americana (Defrance) (p. 27).

16. Hinge of left valve (U. S. Nat. Mus. 325482), Neills Eddy Landing, Cape Fear River, N. C.; natural size, figured to show 

partial encroachment of ligament area on dental series.

17. Hinge of left valve (U. S. Nat. Mus. 325482); natural size, figured to show further encroachment of ligament area on dental 

series.

18. Exterior of juvenile (U. S. Nat. Mus. 325482); height 11.5 millimeters; width 11.7 millimeters.

19. Interior of same juvenile figured to show dentition.

20. Exterior of left valve (U. S. Nat. Mus. 325482); height 85.5 millimeters; width 84.0 millimeters.

21. Interior of same valve.

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 1

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20

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PLATE 2

FIGURE 1. Barbatia (Granoarca) propatula (Conrad) (p. 22). Exterior of right valve and hinge of left valve; height 57.0 ± millimeter 

width 100.0 ± millimeter. (After Conrad.)

FIGURE 2. Anadara (Cunearca) scalaris (Conrad) (p. 26). Exterior of left valve and hinge of right valve; height 54.0 ± millimeter; 

width 64.0 ± millimeter. (After Tuomey and Holmes.)

FIGURE 3. Glycymeris duplinensis Ball (p. 27). Interior of holotype, a left valve (U. S. Nat. Mus. 114941); height 10.0 millimeters; 

width 9.0 millimeters. (After Ball.)

FIGURE 4. Anadara lienosa (Say) (p. 23). Interior of right valve (U. S. Nat. Mus. 325428); height 69.0 millimeters; width 117.0 

millimeters.

FIGURE 5. Anadara protracta (Rogers and Rogers) (p. 24). Interior of right valve; height 40.0 ± millimeters; width 86.0 ± millimeters. (After Rogers and Rogers.)

FIGURE 6. Anadara carolinensis (Wagner) (p. 25). Interior of right valve (Wagner Free Inst. Sci. Philadelphia); height 55.0 millimeters; width 56.0 millimeters. (After Ball.)

FIGURE 7. Anadara lienosa (Say) (p. 23). Exterior of right valve (U. S. Nat. Mus. 325428), from Wilmington, N. C.; height 69.0 

millimeters; width 117.0 millimeters.

147
PLATE 3

FIGURE 1. Anadara magnoliana Gardner, n. sp. (p. 25). Exterior of holotype, a right valve (U. S. Nat. Mus. 325486), from Natural 

Well, Duplin County, N. C.; height 34.3 millimeters; width 46.7 millimeters.

FIGURE 2. Anadara callicestosa (Ball) (p. 24). Detail of sculpture of holotype. (After Dall.)

FIGURE 3. Anadara protracta (Rogers and Rogers) (p. 24). Exterior of right valve; height 40.0 ± millimeters; width 86.0 ± millimeters. (After Rogers and Rogers.)

FIGURE 4. Anadara magnoliana Gardner, n. sp. (p. 25). Interior of holotype.

FIGURE 5. Anadara magnoliana Gardner, n. sp. (p. 25). Detail of sculpture of holotype.

FIGURE 6. Anadara callicestosa (Dall) (p. 24). Exterior of holotype, a left valve (U. S. Nat. Mus. 146264); height 27.0 millimeters; 

width 32.0 millimeters. (After Dall.)

FIGURE 7. Anadara magnoliana Gardner, n. sp. (p. 25). Interior of right valve (U. S. Nat.Mus. 325487); height 31.0 millimeters; 

width 39.0 millimeters.

FIGURE 8. Anadara callicestosa wilsoni Gardner, n. subsp. (p. 24). Detail of sculpture of holotype.

FIGURE 9. Anadara callicestosa wilsoni Gardner, n. subsp. (p. 24). Exterior of holotype, a left valve (II. S. Nat. Mus. 325488); 

height 30.6 millimeters; width 34.3 millimeters.

FIGURES 10-11. Pododesmus (Moniaf) philippi Gardner, n. sp. (p. 41).

10. Interior of holotype, a left valve (II. S. Nat. Mus. 325497); height 35.7 millimeters; width 36.0 millimeters.

11. Detail of sculpture of holotype.

FIGURE 12. Anadara callicestosa wilsoni Gardner, n. subsp. (p. 24). Interior of holotype. 

FIGURE 13. Pododesmus (Monial) philippi Gardner, n. sp. (p. 41). Exterior of holotype. 

FIGURES 14—16. Crenella precursor Gardner, n. sp. (p. 30).

14. Hinge of holotype, X 6.

15. Exterior of holotype, a right valve (U. S. Nat. Mus. 325498); height 7.6 millimeters; width 6.4 millimeters.

16. Interior of holotype. 

FIGURE 17. Ostrea waccamawensis Gardner, n. sp. (p. 41). Exterior of holotype, a left valve (II. S. Nat. Mus. 497063); height

68.0 millimeters; width 57.0 millimeters. 

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PLATE 4

FIGURE 1. Chlamys (Lyropecten) jeffersonia septenaria (Say) (p. 34). Exterior of left valve; height 70.0 millimeters; width 70.0 

millimeters. (After Say.)

FIGURE 2. Chlamys (Lyropecteri) jeffersonia (Say) (p. 32). Exterior of left valve; "length 5.3 inches; breadth 5.7 inches." (After 

Say.)

FIGURE 3. Chlamys (Placopecten) virginiana (Conrad) (p. 38). Exterior of holotype, a right valve (Acad. Nat. Sci. Philadelphia 

1620); height 57.8 millimeters; width 58.8 millimeters.

FIGURE 4. Pecten (Euvola) raveneli Ball (p. 30). Exterior of holotype, a right valve (U. S. Nat. Mus. 107750); height 42.0 millimeters; width 47.0 millimeters. (After Ball.)

FIGURE 5. Chlamys (Lyropecten) madisonia (Say) (p. 32). Exterior of left valve (U. S. Nat. Mus. 325490); height 117.0 millimeters; 

width 126.0 millimeters.

149
PLATE 5

FIGURES 1-2. Chlamys decemnaria (Conrad) (p. 31).

1. Exterior of left valve (U. S. Nat. Mus. 325496); height 18.0 millimeters; width 15.7 millimeters.

2. Exterior of left valve (U. S. Nat. Mus. 325495); height 27.3 millimeters; width 25.0 millimeters.

FIGURE 3. Pecten sp. cf. P. (Plagioctenium) gibbus (Linnaeus), s. 1. (p. 31). Exterior of right valve (U. S. Nat. Mus. 146256); 

height 43.0 millimeters; width 44.0 millimeters.

FIGURE 4. Chlamys (Placopecleri) marylandica (Wagner) (p. 38). Exterior of left valve (U. S. Nat. Mus. 145991); height 67.5 millimeters; width 66.0 millimeters.

FIGURE 5. Glycymeris duplinensis Ball (p. 27). Exterior of holotype, a left valve (U. S. Nat. Mus. 114941); height 10.0 millimeters; 

width 9.0 millimeters. (After Ball.)

FIGURES 6-7. Chlamys decemnaria (Conrad) (p. 31).

6. Exterior of right valve (U. S. Nat. Mus. 325495); height 27.3 millimeters; width 25.0 millimeters.

7. Exterior of right valve (U. S. Nat. Mus. 325494); height 43.0 millimeters; width 42.0 millimeters. 

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 5
GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 6

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PLATE 6

FIGURE 1. Chlamys (Placopecten) clintonia (Say) (p. 37). Exterior of left valve; height 100.0+ millimeters; width 104.0 millimeters

(After Glenn.) 

FIGURES 2-3. Chlamys (Placopecten) marylandica (Wagner) (p. 38).

2. Exterior of right valve (U. S. Nat. Mus. 143966); height 53.5 millimeters; width 47.0+ millimeters.

3. Exterior of left valve (U. S. Nat. Mus. 145991); height 81 millimeters; width 70 millimeters. 

FIGURE 4. Chlamys (Placopecten) clintonia (Say) (p. 37). Exterior of left valve; "length 4 inches; breadth rather more." (After

Say.)

FIGURE 5. Chlamys (Lyropecten}\ peedeensis (Tuomey and [Holmes) (p. 35). Detail of sculpture. (After Tuomey and Holmes.) 

FIGURES 6-8. Chlamys (Lyropecten) ernestsmithi (Tucker) (p. 34).

6. Detail of sculpture.

7. Exterior of right valve (U. S. Nat. Mus. 325492); height 70.0 millimeters; width 67.0 millimeters.

8. Exterior of left valve (U. S. Nat. Mus. 325492); height 101.5 millimeters; width 100.0 millimeters.

151
PLATE 7

FIGURE 1. Chlamys (Aequipecteri) eborea (Conrad) (p. 36). Exterior of right valve (double valves); height 83.0±millimeters; width

90.0 ± millimeters. (After Tuomey and Holmes.) 

FIGURES 2-4. Chlamys (Aequipecteri) comparilis (Tuomey and Holmes) (p. 37).

2. Exterior of right valve of holotype (double valves); height 65.0±millimeters; width 65.0±millimeters. (After Tuomey and 

Holmes.)

3. Detail of sculpture and of ventral margin of holotype. (After Tuomey and Holmes.) ,

4. Profile of double valves of holotype; convexity 29.0 ± millimeters. (After Tuomey and Holmes.) 

FIGURES 5—6. Chlamys (Aequipecteri) eborea (Conrad) (p. 36).

5. Profile of double valves; convexity 23.0± millimeters. (After Tuomey and Holmes.)

6. Detail of sculpture and of ventral margin. (After Tuomey and Holmes.) 

FIGURE 7. Chlamys (Aequipecteri) comparilis (Tuomey and Holmes) (p. 37). Exterior of left valve of holotype(?). (After Tuomey

and Holmes.)

FIGURE 8. Chlamys (Aequipecteri) eborea (Conrad) (p. 36). Exterior of left valve. (After Tuomey and Holmes.) 

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PL4TE 7

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 8

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PLATE 8

FIGURES 1—2. Amusium mortoni (Ravenel) (p. 39).

1. Interior of right valve; height 178 millimeters; width 195 millimeters. (After Tuomey and Holmes.)

2. Profile of double valves; convexity 31 millimeters. (After Tuomey and Holmes.)

153

401033—43———12
PLATE 9

FIGURE 1. Chlamys (Lyropecteri) planicosta Gardner, n. sp. (p. 34). Exterior of right valve (U. S. Nat. Mus. 325493); height 111.0

millimeters; width 118.0± millimeters. 

FIGURES 2-6. Coralliophaga? microreticulata Gardner (p. 66). Cotypes (U. S. Nat. Mus. 325560).

2. Cluster of burrows showing openings at smaller ends, X 3.

3. Fragment of ventral portion of shell, X2.

4. Fragment of anterior portion of right valve, X 2.

5. Fragment of anterior portion of left valve, X 2.

6. Cluster of burrows, natural size.

FIGURE 7. Chlamys (Lyropecteri) madisonia (Say) (p. 32). Exterior of right valve (U. S. Nat. Mus. 325490); height 117.0 millimeters; width 131.0 millimeters. 

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 9

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PLATE 10

FIGURES 1-2. Thracia maddelysensis Gardner, n. sp. (p. 44).

1. Exterior of holotype, a right valve (U. S. Nat. Mus. 325508); height 4.0 millimeters; width 5.0 millimeters.

2. Interior of holotype. 

FIGURE 3. Periploma (Cochlodesma) antiqua Conrad (p. 42). Interior of right valve of holotype and exterior of left valve; height

39.0+_ millimeters; width 52.5 +_ millimeters. (After Conrad.) 

FIGURE 4. Thracia conradi Couthouy (p. 43). Exterior of left valve and overtopping margin of right; height 74.0 millimeters; width

90.0 ± millimeters. (After Gould, 1870, and Ball, 1889.) 

FIGURES 5-10. Thracia transversa H. C. Lea (p. 43).

5. Interior of right valve (Acad. Nat. Sci. Philadelphia 1585); height 1.8+ millimeters; width 2.6± millimeters.

6. Interior of right valve (U. S. Nat. Mus. 325509); height 4.8± millimeters; width 7.3 millimeters.

7. Exterior of same right valve.

8. Interior of left valve (U. S. Nat. Mus. 325509); height 5.1± millimeters; width 7.9 millimeters.

9. Exterior of same left valve.

10. Interior of right vplve (Acad. Nat. Sci. Philadelphia 1585); height 1.8± millimeters; width 2.6± millimeters. 

FIGURE 11. Verticordia (Trigonulina) chowanensis Gardner, n. sp. (p. 51). Interior of holotype, a right valve (U. S. Nat. Mus.

325507); height 5.1 millimeters; width 5.6 millimeters. 

FIGURES 12-13. Verticordia (Trigonulina) rogersi Gardner, n. sp. (p. 50).

12. Interior of holotype, a right valve (U. S. Nat. Mus. 325506); height 2.5 millimeters; width 2.8 millimeters.

13. Exterior of right valve of holotype.

FIGURE 14. Verticordia (Trigonulina) emmonsii Conrad (p. 50). Exterior of right valve (U. S. Nat. Mus. 145332); height 6.0 millimeters; width 6.8 millimeters.

FIGURE 15. Verticordia (Trigonulina) chowanensis Gardner, n. sp. (p. 51). Exterior of holotype shown in figure 11.

FIGURE 16. Pandora (Kennerlia) arenosa Conrad (p. 45). Interior of left valve of topotype (U. S. Nat. Mus. 325505); height 8.0 

millimeters; width 14.5 millimeters.

FIGURES 17-18. Pandora (Clidiophora) crassidens Conrad (p. 46).

17. Interior of right valve from Cove Point, St. Marys River, Md., slightly enlarged. (After Glenn.)

18. Exterior of left valve from Cove Point, St. Marys River, Md., slightly enlarged. (After Glenn.) 

FIGURES 19-20. Pandora (Kennerlia) arenosa Conrad (p. 45).

19. Exterior of topotype (U. S. Nat. Mus. 325505), a right valve, the margin of the slightly larger left valve visible dorsally and 

ventrally; height of double valves 8.5 millimeters; width 16.6 millimeters.

20. Exterior of double valves from left. 

FIGURE 21. Pandora (Kennerlia) dalli Gardner, n. sp. (p. 45). Interior of holotype, a left valve (U. S. Nat. Mus. 325503); height

11.1 millimeters; width 19.8 millimeters. 

FIGURES 22-23. Pandora (Kennerlia) naviculoides Gardner, n. sp. (p. 46).

22. Interior of holotype, a left valve (U. S. Nat. Mus. 325504); height 8.9 millimeters; width 16.6 millimeters.

23. Exterior of holotype.

FIGURE 24. Pandora (Kennerlia) dalli Gardner, n. sp. (p. 45). Exterior of holotype. 

FIGURE 25. Pandora (Clidiophora) crassidens majorina Gardner, n. subsp. (p. 47). Interior of paratype, a left valve (U. S. Xat.

Mus. 325500); height 25.0± millimeters; width 35.0± millimeters. 

P'IGURE 26. Pandora (Kennerlia) dalli Gardner, n. sp. (p. 45). Interior of paratype (U. S. Nat. Mus. 325503); height 10.2 millimeters;

width 18.8 millimeters. 

FIGURE 27. Pandora (Clidiophora) luomeyi Gardner and Aldrich (p. 48). Exterior of holotype, a left valve (U. S. Nat. Mus. 325502);

height 9.5 millimeters; width 21.0 millimeters; convexity 2.0 millimeters. 

FIGURE 28. Pandora (Clidiophora} crassidens majorina Gardner, n. subsp. (p. 47). Exterior of holotype, a left value (U. S. Nat.

Mus. 325501); height 37.8 millimeters; width 59.6 millimeters.

155
PLATE 11

FIGURE 1. Dosinia (Dosinidia) elegans Conrad (p. 122). Exterior of right valve (U. S. Nat. Mus. 497065) from Shell Creek, De

Soto County, Fla.; height 61.0 millimeters; width 68.0 millimeters. 

FIGURES 2-3. Pandora (Clidiophora) prodromes Gardner and Aldrich (p. 48). Holotype, the two valves of a single individual (U. S.

Nat. Mus. 325499) from Yorktown, Va.; height 21.0 millimeters; width 33.0 millimeters.

2. Exterior of left valve. (After Gardner and Aldrich.)

3. Interior of right valve. (After Gardner and Aldrich.) 

FIGURE 4. Dosinia (Dosinidia) acetabulum Conrad (p. 120). Exterior of right valve and hinge of left valve of holotype. (After

Conrad.) 

FIGURE 5. Isocardia fraterna Carolina Ball (p. 67). Exterior of specimen, a right valve (U. S. Nat. Mus. 325558) from Delaware,

Nottoway River, Va.; height 71.0 millimeters; width 73.0 millimeters; semidiameter 25.0 millimeters. 

FIGURE 6. Plica'ula marginata Say (p. 40). Interior of right valve from the Darlington district, S. C.; height 34.0± millimeters;

width 30.0 ± millimeters. (After Tuomey and Holmes.) 

FIGUP.E 7. Pandora (Clidiophora) trilineata Say (p. 49). Exterior of left valve (U. S. Nat. Mus. 61028), Recent in Tampa Bay,

Fla.; height 8.0 millimeters; width 20.0 millimeters; diameter 2.0 millimeters. (After Dall.) 

FIGURE 8. Plicatula marginata Say (p. 40). Interior of left valve from the Darlington district, S. C.; height 34.0± millimeters;

width 30.0 millimeters. (After Tuomey and Holmes.) 

FIGURES 9-10. Pandora (Clidiophora) tuomeyi Gardner and Aldrich (p. 48).

9. Interior of holotype, a left valve (U. S. Nat. Mus. 325502) from Walkers Bluff, Bladen County, N. C.; height 9.5 millimeters: width 21.0 millimeters. (After Gardner and Aldrich.)

10. Interior of paratype, a right valve (U. S. Nat. Mus. 325502) from Walkers Bluff, Bladen County, N. C.; height 11.0 millimeters. (After Gardner and Aldrich.) 

FIGURES 11-12. Pandora (Clidiophora) prodromes Gardner and Aldrich (p. 48).

11. Interior of left valve of holotype shown in figure 2. (After Gardner and Aldrich.)

12. Exterior of right valve of holotype shown in figure 3. (After Gardner and Aldrich.) 

FIGURES 13—14. Plicatula marginata Say (p. 40).

13. Ventral margin of paired valves from Darlington district, S. C. (After Tuomey and Holmes.)

14. Exterior of left (?) valve from the Darlington district, S. C.; height 29.0 ± millimeters; width 33.0± millimeters. (After

Tuomey and Holmes.)

FIGURE 15. Isocardia fraterna Say (p. 67). Exterior of right valve and hinge of right valve. (After Say.) 

156
GEOLOGICAL SURVEY

PROFESSIONAL PAPEE 199 PLATE 11

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PELECYPODS.
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PLATE 12

FIGURES 1-4. Astarte symmetrica Conrad (p. 51). Topotvpes, a right and a left valve of different individuals (U. S. Nat. Mus. 

325516) from Yorktowri, Va.

1. Exterior of right valve; height 16.9 millimeters; width 17.7 millimeters.

2. Interior of left valve; height 17.0 millimeters; width 17.5 millimeters.

3. Interior of right valve shown in figure 1.

4. Exterior of left valve shown in figure 2.

FIGURES 5-8. Astarte exaltata Conrad (p. 52). A right and a left valve of different individuals (U. S. Nat. Mus. 325519) from the 

mouth of Baileys Creek, James River, Va.

5. Interior of left valve; height 16.0 millimeters; width 17.0 millimeters.

6. Exterior of left valve shown in figure 5.

7. Exterior of right valve; height 19.0 millimeters; width 18.8 millimeters.

8. Interior of right valve shown in figure 7.

FIGURES 9-10. Astarte roanokensis Gardner, n. sp. (p. 53). Two cotypes, a right and a left valve of different individuals (U. S. 

Nat. Mus. 325523) from Halifax, N. C.

9. Interior of left cotype; height 24.2 millimeters; width 23.9 millimeters.

10. Exterior of right cotype; height 24.4 millimeters; width 23.9 millimeters.

FIGURES 11-12. Astarte hertfordensis Gardner, n. sp. (p. 53). Holotype, the right and left valves of a single individual (U. 8. Nat. 

325526) from Murfreesboro, Hertford County, N. ~C.

11. Interior of left valve of holotype; height 23.0 millimeters; width 25.7 millimeters.

12. Exterior of right valve of holotype. 

FIGURES 13-14. Astarte arata Conrad (p. 55).

13. Exterior of right valve (U. S. Nat. Mus. 325517) from Halifax, N. C., height 21.5 millimeters; width 21.0 millimeters.

14. Exterior of left valve (U. S. Nat. Mus. 325517) from Halifax, N. C.; height 20.0 millimeters; width 21.0 millimeters. 

FIGURE 15. Astarte coheni Conrad (p. 53). Exterior of right valve; height 18.0± millimeters; width 18.5± millimeters. (After

Conrad.) 

FIGURES 16-17. Astarte stephensoni Gardner, ri. sp. (p. 54). Holotype, a left valve (U. S. Nat. Mus. 325528) from Halifax, N. C.;

height 22.7 millimeters; width 24.2 millimeters; convexity 6.3 millimeters.

16. Exterior of holotype.

17. Interior of holotype. 

FIGURE 18. Astarte hertfordensis meherrinensis Gardner, n. subsp. (p. 54). Exterior of holotype, a right valve (U. S. Nat. Mus.

325531); height 23.0 millimeters; width 24.8 millimeters.

FIGURES 19-20. Astarte (Ashtarotha) rappahannockensis Gardner, n. p. (p. 56). Holotype, aright valve (U. S. Nat. Mus. 325527) 

from Urbanna, Va.; height 25.8 millimeters; width 28.6 millimeters.

19. Exterior of holotype.

20. Interior of holotype. 

FIGURE 21. Astarte hertfordensis Gardner, n. sp. (p. 53). Holotype (U. S. Nat. Mus. 325526) from Murfreesboro, N. C. Double

valves viewed from the front; diameter 14.4 millimeters. 

FIGURE 22. Astarte (Ashtarotha) griftonensis Gardner, ri. sp. (p. 57). Exterior of holotype, a left valve (U. S. Nat. Mus. 325524)

from 2 miles east of Grifton, Pitt County, N. C.; height 23.8 millimeters; width 27.0 millimeters. 

FIGURES 23-24. Astarte berryi Gardner, n. sp. (p. 56). Holotype, a left valve (U. S. Nat. Mus. 325533) from 2J4 miles northwest

of Chocowinity, Beaufort County, N. C.; height 25.0 millimeters; width 27.2 millimeters.

23. Interior of holotype.

24. Exterior of holotype. 

FIGURE 25. Astarte (Ashtarotha) undulata Say (p. 57). Exterior of right valve (U. S. Nat. Mus. 325521) from 1% miles northeast

of Chocowinity, N. C.; height 25.0 millimeters; width 28.5 millimeters.

FIGURES 26-27. Astarte (Ashtarotha) undulata vaginulata Dall (p. 58). Lectotype, a right valve (U. S. Nat. Mus. 146121) from 

Grove Wharf, James River, Va.; height 22.4 millimeters; width 27.5 millimeters.

26. Exterior of lectotype.

27. Interior of lectotype.

FIGURE 28. Astarte (Ashtarotha) griftonensis Gardner, ri. sp. (p. 57). Interior of holotype shown in figure 22.

FIGURES 29-30. Astarte (Ashtarotha) undulata deltoidea Gardner, n. subsp. (p. 59). Holotype, a right valve (U. S. Nat. Mus. 325525) 

from 7 to 7}£ miles below Zuni, Isle of Wight County, Va.; height 23.5 millimeters; width 24.7 millimeters.

29. Interior of holotype.

30. Exterior of holotype. 

FIGURE 31. Astarte (Ashtarotha) undulata Say (p. 57). Exterior of left valve (U. S. Nat. Mus. 325520) from Murfreesboro, N. C.;

height 20.8 millimeters; width 24.0 millimeters.

FIGURES 32-34. Astarte (Ashtarotha) concentrica Conrad (p. 59). Figured specimens (U. S. Nat. Mus. 325518) from Colerairi Landing, Chowan River, N. C.

32. Interior of right valve; height 21.2 millimeters; width 25.0 millimeters.

33. Exterior of right valve shown in figure 32.

34. Interior of left valve; height 22.3 millimeters: width 28.0 millimeters. 

FIGURES 35-36. Astarte (Ashtarotha) undulata deltoidea Gardner, ri. subsp. (p. 59). Paratype, a right valve (U. S. Nat. Mus.

325532) from Zuni, Isle of Wight County, Va.; height 22.5 millimeters; width 19.0±millimeters.

35. Interior of paratype.

36. Exterior of paratype. 

FIGURE 37. Astarte (Ashtarotha) concentrica conradi Gardner, n. subsp. (p. 60). Interior of cotype, a right valve (U. S. Nat. Mus.

325530) from 4 to 5 miles below Lumberton, Robeson County, N. C.; height 15.7millimeters; width 19.0 millimeters. 

FIGURES 38-39. Astarte (Ashtarotha) concentrica bella Conrad (p. 60). Left valve (U. S. Nat. Mus. 325522) from Lieutenant Run,

Petersburg, Va.; height 25.7 millimeters; width 29.0 millimeters.

38. Interior of left valve.

39. Exterior of left valve.

FIGURE 40. Astarte (Ashtarotha) concentrica Conrad (p. 59). Exterior of left valve shown in figure 34.

FIGURE 41. Astarte (Ashtarotha) concentrica conradi Gardner, n. subsp. (p. 60). Exterior of cotype, a left valve (U. S. Nat. Mus. 

325530) from 4 to 5 miles below Lumberton, Robeson County. N. C.; height 16.8 millimeters; width 21.3 millimeters.

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PLATE 13

FIGURES 1-4. Glans (Pleuromeris) tridentata decemcostata Conrad (p. 71). Double valves arid the right and left valves of other 

individuals (U. S. Nat. Mus. 325572) from 2 miles below Lumberton, Robeson County, N. C.

1. Exterior of double valves viewed from left; height 6.8 millimeters; width 7.8 millimeters.

2. Interior of right valve; height 6.8 millimeters; width 8.0 millimeters.

3. Interior of left valve; height 6.7 millimeters; width 7.7 millimeters.

4. Double valves viewed from front; diameter 5.2 millimeters.

FIGURE 5. Pseudochama corticosa (Conrad) (p. 89). Double valves viewed from left. (After Tuomey and Holmes.) 

FIGURES 6-9. Glans (Pteromeris) perplana (Conrad) (p. 72). Right arid left valves of different individuals (U. S. Nat. Mus. 325512) 

from Neills Eddy Landing, Cape Fear River, N. C.

6. Exterior of left valve; height 8.0 millimeters; width 7.8 millimeters.

7. Interior of left valve shown in figure 6.

8. Interior of right valve; height 7.5 millimeters; width 7.9 millimeters.

9. Exterior of right valve shown in'figure 8.

FIGURES 10-11. Crassinella dupliniana Dall (p. 64). Holotype, double valves (U. S. Nat. Mus. 114922) from Natural Well, Duplin 

County, N. C.; height 3.1 millimeters; width 3.2 millimeters.

10. Exterior of left valve. (After Dall.)

11. Interior of right valve. (After Dall.)

FIGURES 12-15. Chama striata Emmons (p. 88). Right and left valves of different individuals (U. S. Nat. Mus. 325541) from 

Neills Eddy Landing, Cape Fear River, N. C.

12. Exterior of left valve; height 24.0 millimeters; width 24.0 millimeters.

13. Interior of right valve; height 17.0 millimeters; width 18.5 millimeters.

14. Exterior of right valve shown in figure 13.

15. Interior of left valve shown in figure 12.

FIGURE 16. Pseudochama corticosa (Conrad) (p. 89). Interior of right valve. (After Tuomey and Holmes.) 

FIGURE 17. Phacoides (Cardiolucina) postalveatus Gardner, n. sp. (p. 77). Exterior of holotype, a left valve (U. S. Nat. Mus. 325539)

from Yorktown, Va.; height 3.3 millimeters; width 3.4 millimeters. 

FIGURE 18. Crassinella nansemondensis Gardner, n. sp. (p. 64). Interior of paratype (U. S. Nat. Mus. 325515), from \% miles

southeast of Reids Ferry, Nansemond County, Va.; height 2.7 millimeters; width 3.1 millimeters. 

FIGURES 19-22. Glans (Pteromeris) perplana abbreviate (Conrad) (p. 72). A right and a left valve (U. S. Nat. Mus. 325513) from

Magnolia, N. C.

19. Interior of right valve; height 5.3 millimeters; width 5.0 millimeters.

20. Exterior of right valve.

21. Exterior of left valve; height 3.1 millimeters; width 3.2 millimeters.

22. Interior of left valve.

FIGURES 23-24. Phacoides (Lucinisca) cribrarius (Say) (p. 77). A left valve (U. S. Nat. Mus. 325535) from Yorktown, Va.; height 

10.0 millimeters; width 10.6 millimeters.

23. Interior of left valve, X 2.

24. Exterior of left valve, X 2.

FIGURES 25-26. Phacoides (Cardiolucina) trisulcatus multistriatus (Conrad) (p. 76). A left valve (U. S. Nat. Mus. 325538) from 

city rock quarry, Wilmington, N. C.; height 5.8 millimeters; width 6.3 millimeters.

25. Interior of left valve.

26. Exterior of left valve. 

FIGURE 27. Crassinella nansemondensis Gardner, n. sp. (p. 64). Interior of holotype (U. S. Nat. Mus. 325514) half a mile below

the Suffolk dam, Nansemond County, Va.; height 3.3 millimeters; width 3.5 millimeters.

FIGURE 28. Pseudochama corticosa (Conrad) (p. 89). Profile of double valves from front. (After Tuomey and Holmes.) 

FIGURES 29-30. Phacoides (Lucinisca) cribrarius (Say) (p. 77). A right valve (U. S. Nat. Mus. 525536) fiom 5 miles northeast of

Smithfield, Va.; height 12.8 millimeters; width 12.9 millimeters.

29. Exterior of right valve, X 2.

30. Interior of right valve, X 2.

FIGURES 31-32. Ctena microimbricata Gardner, n. sp. (p. 75). Holotype, a right valve (U. S. Nat. Mus. 325540) from Natural Well, 

Duplin County, N. C.; height 9.8 millimeters; width 11.2 millimeters.

31. Detail of sculpture of holotype, X 10.

32. Exterior of holotype.

FIGURE 33. Ctena speciosa (Rogers arid Rogers) (p. 75). Exterior of right valve (U. S. Nat. Mus. 145067) from Bellefield, York 

River, Va.; height 14.1 millimeters; width 16.4 millimeters.

FIGURES 34-37. Phacoides (Parvilucina) multilineatus (Tuomey and Holmes) Dall (p. 78). A right and a left valve of different individuals (U. S. Nat. Mus. 325537) from Neills Eddy Landing, Cape Fear River, N. C.

34. Interior of left valve; height 7.5 millimeters; width 7.3 millimeters.

35. Interior of right valve; height 6.5 millimeters; width 6.6 millimeters.

36. Exterior of right valve shown in figure 35.

37. Exterior of left valve shown in figure 34. 

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 13

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GEOLOGICAL SURVEY PROFESSIONAL TAPER 199 PLATE 14

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PELECYPODS
FIGURE 1. Erycina carolinensis elongata Gardner, n. subsp. (p. 82). Interior of holotype, a left valve (U. S. Nat. Mus. 325542)

from Neills Eddy Landing. Cape Fear River, N. C.; height 7.5 millimeters; width 12.7 millimeters. 

FIGURES 2-5. Bornia triangula Dall (p. 82).

2. Hinge of holotype, a right valve (Acad. Nat. Sci. Philadelphia 1597) from Petersburg, Va., X 12.

3. Interior of paratype, a left valve (U. S. Nat. Mus. 325547) from Yorktowri, York River, Va.; height 3.0 millimeters; width 

3.3 millimeters.

4. Interior of holotype, a right valve (Acad. Nat. Sci. Philadelphia 1597) from Petersburg, Va., X 4.

5. Exterior of holotype shown in figure 4, X 4.

FIGURES 6-7. Sportella gibberosa Gardner, n. sp. (p. 84). Cotypes, a right and a left valve of different individuals (U. S. Nat. Mus. 

325544) from Walkers Bluff, Cape Fear River, Bladen County, N. C.

6. Exterior of right valve; height 3.2 millimeters; width 4.5 millimeters.

7. Interior of left valve; height 3.3 millimeters; width 4.5 millimeters. 

FIGURE 8. Mysella stantoni (Dall) (p. 86). Interior of holotype, a right valve (U. 8. Nat. Mus. 115102) from Natural Well, Dupliii

County, N. C.; height 2.2 millimeters; width 3.6 millimeters. (After Dall.) 

FIGURE 9. Erycina carolinensis Dall (p. 81). Interior of lectotype, a right valve (U. S. Nat. Mus. 115096) from Natural Well,

Duplin County. -N. C.; height 5.7 millimeters; width 9.0 millimeters. (After Dall.) 

FIGURE 10. Bornia triangula Dall (p. 82). Interior of paratype, a right valve (U. S. Nat. Mus. 325547) from Yorktown, York

County, Va.; height 3.0 millimeters; width 3.3 millimeters. 

FIGURES 11-12. Bornia bladenensis Gardner, n. sp. (p. 83). Holotype, a right valve (U. S. Nat. Mus. 325546) from Walkers Bluff,

Bladen County, N. C.; height 3.9 millimeters; width 4.75 millimeters. 

11. Interior of holotype. 12. Exterior of holotype. 

FIGURES 13-14. Mysella majorina Gardner, n. sp. (p. 86). Two cotypes, the right arid left valves of different individuals (U. S.

Nat. Mus. 325549) from Neills Eddy Landing, Cape Fear River, N. C.

13. Interior of right valve; height 2.7 millimeters; width 4.0 millimeters.

14. Exterior of left valve; height 2.7 millimeters; width 4.1 millimeters.

FIGURES 15-16. Mysella velaini Gardner, n. sp. (p. 86). Holotype, a right valve (U. S. Nat. Mus. 325548) from Walkers Bluff, 

Bladen County, N. C.; height 3.0 millimeters; width 4.2 millimeters.

15. Exterior of holotype. 16. Interior of holotype. 

FIGURES 17-18. Mysella bladenensis Gardner, n. sp. (p. 86). Holotype, a right valve (U. S. Nat. Mus. 325550) from Walkers Bluff,

Bladen County, N. C.; height 3.0 millimeters; width 4.5 millimeters. 

17. Interior of holotype. 18. Exterior of holotype.

FIGURES 19-20. Sportella constricta (Conrad) (p. 83). A right and a left valve of different individuals (U. S. Nat. Mus. 155730) 

from the Caloosahatchee River, Fla.

19. Interior of right valve; height 6.0 millimeters; width 9.0 millimeters.

20. Interior of left valve; height 5.7 millimeters; width 9.0 millimeters.

FIGURES 21-22. Sportella waccamawensis Gardner, n. sp. (p. 85). Holotype, a right valve (U. S. Nat. Mus. 325545) from Walkers 

Bluff, Cape Fear River, N. C.; height 8.2 millimeters; width 13.5 millimeters.

21. Exterior of holotype. 22. Interior of holotype. 

FIGURE 23. Aligena rhomboidea Gardner, n. sp. (p. 87). Interior of holotype, a left valve (U. S. Nat. Mus. 325552) from Natural

Well, Duplin County, N. C.; height 7.8 millimeters; width 8.8 millimeters. 

FIGURES 24-26. Aligena laevis H. C. Lea (p. 87). A right valve (Acad. Nat. Sci. Philadelphia 1582).

24. Interior of right valve, X 4. 25. Exterior of right valve, X 4. 26. Hinge of right valve, X 12. 

FIGURES 27-29. Sportella compressa (H. C. Lea) (p. 85). A left valve (Acad. Nat. Sci. Philadelphia 1596).

27. Interior of left valve, X 4. 28. Exterior of left valve, X 4. 29. Hinge of left valve, X 12. 

FIGURE 30. Sportella calpix Gardner, n. sp. (p. 84). Interior of holotype, a right valve (U. S. Nat. Mus. 325543) from \% miles

below Tar Ferry, Hertford County, N. C.; height 10.2 millimeters; width 14.7 millimeters. 

FIGURES 31-32. Aligena chowanensis Gardner, n. sp. (p. 87). Holotype, a right valve (U. S. Nat. Mus. 325551) from Colerain Landing,

Bertie County, N. C.; height 4.7 millimeters; width 4.7 millimeters. 

31. Exterior of holotype. 32. Interior of holotype. 

FIGURES 33-36. Incertae sedis. (p. 74). Two valves of a single individual (U. S. Nat. Mus. 325557) from Suffolk, Va.; height 1.7

millimeters; width 1.8 millimeters. 

33. Interior of left valve, X 12. 34. Exterior of left valve, X 5. 35. Exterior of right valve, X 5.

36. Interior of right valve, X 12.

FIGURES 37-38. Diplodonta leana eoleana Gardner, n. subsp. (p. 80). Holotype, a right valve (U. S. Nat. Mus. 325556) from 

Urbanna, Rappahannock River, Va.; height 18.0 millimeters; width 19.1 millimeters.

37. Exterior of right valve. 38. Interior of right valve.

FIGURE 39. Sportella calpix Gardner, n. sp. (p. 84). Exterior of holotype shown in figure 30. 

FIGURES 40-41. Diplodonta caloosaensis Dall. (p. 80). Figured specimen, a left valve (U. S. Nat. Mus. 325553) Neills Eddy

Landing, Cape Fear River, N. C.; height 20.6 millimeters; width 22.3 millimeters; convexity 6.5 millimeters. 

40. Profile of figured specimen. 41. Exterior of figured specimen. 

FIGURES 42-43. Diplodonta (Phlyctiderma) soror (C. B. Adams) (p. 81). A left valve (U. S. Nat. Mus. 325555) from Natural Well,

N. C.; height 12.3 millimeters; width 12.7 millimeters. 

42. Exterior of left valve. 43. Interior of left valve. 

FIGURE 44. Cooperella carpenteri Dall (p. 119). Interior of holotype of "Diplodonta yorkensis" Dall, a left valve (U. S. Nat. Mus.

144548) from Yorktown, Va.; height 8.7 millimeters; width 10.9 millimeters. (After Dall.) 

FIGURE 45. Crassinella lunulata harrisi Gardner, ri. subsp. (p. 63). Exterior of left valve of holotype (U. S. Nat. Mus. 1630) from

Yorktown, Va.; height 5.1 millimeters; width 5.2 millimeters. (After Dall.) 

FIGURE 46. Erycinella ovalis Conrad (p. 73). Drawings of hinge. (After Dall.) 

FIGURE 47. Cooperella carpenteri Dall. (p. 119). Interior of right valve (U. S.-Nat. Mus. 155714) from Petersburg, Va., X3

(After Dall.)

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PLATE 15

FIGURES 1-2. Euloxa latisulcata Conrad (p. 65). Left valve (U. S. Nat. Mus. 214407) from the lower layer at old Claremont Wharf, 

James River, Va.; height 20.0 millimeters; width 23.4 millimeters.

1. Exterior of left valve X 2.

2. Interior of left valve, X 2.

FIGURES 3-4. Ccrbicula densata (Conrad) (p. 65). Right valve (U. S. Nat. Mus. 325534) from Wilmington, N. C.; height 29.0 millimeters; width 31.8 millimeters.

3. Interior of right valve.

4. Exterior of right valve.

FIGURES 5-6. Carditamera arata verdevilla Gardner n. subsp. (p. 69). Holotype, a right valve (U. S. Nat. Mus. 325511) from 8 to 9 

miles south of Greenville, Pitt County, N. C.; height 22.3 millimeters; width 46.0 millimeters; convexity 10.0 

millimeters.

5. Exterior of holotype.

6. Interior of holotype.

FIGURES 7-8. Corbicula densata (Conrad) (p. 65). Left valve (U. S. Nat. Mus. 325534) from Wilmington, N. C.; height 26.3 millimeters; width 29.3 millimeters; convexity 9.5 millimeters.

7. Interior of left valve.

8. Exterior of left valve.

FIGURES 9-10. Carditamera columbiana Gardner, n. sp. (p. 69). Holotype, a right valve (U. S. Nat. Mus. 325510) from Neills 

Eddy Landing, Cape Fear River, N. C.; height 27.5 millimeters; width 37.0 millimeters.

9. Exterior of holotype.

10. Interior of holotype.

FIGURES 11-12. Laevicardium sublineatum Conrad (p. 94). Left valve (U. S. Nat. Mus. 325559) from Neills Eddy Landing, Cape 

Fear River, N. C.; height 26.0 millimeters; width 28.5 millimeters.

11. Interior view of left valve.

12. Exterior of left valve.

FIGURES 13-14. Petricola (Rupellaria) grinnelli Olsson (p. 117). Right valve (U. S. Nat. Mus. 325562) from Palmyra Bluff, Halifax 

County, N. C.; height 13.5 millimeters; width 23.5 millimeters.

13. Exterior of right valve, X 2.

14. Interior of right valve, X 2.

FIGURES 15-16. Laevicardium sublineatum Conrad (p. 94). (U. S. Nat. Mus. 325559) from Neills Eddy Landing, Cape Fear River, 

N. C.; height 28.7 millimeters; width 29.0 millimeters.

15. Interior of right valve.

16. Exterior of right valve. 

FIGURE 17. Pleiorytis centenaria Conrad? (p. 119). Exterior of holotype of Petricola (Rupellaria) harrisii Dall (U. S. Nat. Mus.

145020) from Bellefield, York River, Va.; height 20.5 millimeters; width 22.5 millimeters. (After Dall.) 

FIGURE 18. Petricola (Rupellaria) grinnelli Olsson (p. 117). Interior of left valve (U. S. Nat. Mus. 325561) from Wilmington, N. C.;

height 16.0± millimeters; width 24.8 millimeters, X 2. 

FIGURES 19-20. Trachycardium isocardia (Linnaeus) (p. 91). Paired (U. S. Nat. Mus. 57147), Recent from the coast of Florida;

height 47.5 millimeters; width 37.5 millimeters.

19. Exterior of left valve.

20. Interior of right valve. 

FIGURE 21. Trachycardium muricatum (Linnaeus) (p. 92). Exterior of left valve (Wagner Free Inst. Sci.) from Cape Fear River,

N. C.; height 80 millimeters; width 80 millimeters. 

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 15

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GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 16

PELECYPODS
PLATE 16

FIGUEES 1-2. Isocardia fraterna glenni Gardner, n. subsp. (p. 68).

1. Interior of paratype, a left valve (Maryland Geol. Survey, Baltimore, Md., collection) from Jones Wharf, St. Marys County, 

Md ; height 53.3 millimeters; width 67.1 millimeters. (After Glenn.)

2. Exterior of holotype, a right valve (Maryland Geol. Survey, Baltimore, Md., collection)-from Jones Wharf, St. Marys County,

Md.; height 59.0 millimeters; width 73.0 millimeters. (After Glenn.) 

FIGURE 3. Cerastoderma virginianum (Conrad) (p. 91). Exterior of holotype, a right valve from the. James River near Smithfield,

Va.; "length about 4 inches." (After Conrad.) 

FIGURE 4. Cerastoderma laqueatum (Conrad) (p. 90). Exterior of left valve (Maryland Geol. Survey, Baltimore, Md., collection

from Jones Wharf, St. Marys County, Md. X %• (After Glenn.)

FIGURE 5. Cerastoderma acutilaqueatum (Conrad) (p. 90). Exterior of holotype, a right valve from Yorktown, Va.; "length 4 inches; 

height 4^ inches." (After Conrad.)

161

401033-43——13
PLATE IT

FIGURE 1. Tellina egena Conrad (p. 98). Exterior of holotype, a right valve from the James River near Smithfield, Va. X 1.

(After Conrad.) 

FIGURES 2-3. Tellina (Moerella?) calpix Gardner, n. sp. (p. 98). Holotype, a right valve (U. S. Nat. Mus. 325595) from 8 to 9

miles south of Greenville, Pitt County, N. C.; height 8.0 millimeters; width 11.5 millimeters.

2. Interior of holotype, X 4.

3. Exterior of holotype, X 4. 

FIGURE 4. Tellina (Moerella) sayi (Deshayes ms.) Ball (p. 95). Exterior of left valve (U. S. Nat. Mus. 128444), Recent off the coast

of South Carolina; height 10.0 millimeters; width 17.4 millimeters. 

FIGURE 5. Tellina (Moerella) macilenta Ball (p. 97). Exterior of holotype, a right valve (U. S. Nat. Mus. 115045) from Natural

Well, Duplin County, N. C.; height 10.8 millimeters; width 16.5 millimeters. (After Ball.) 

FIGURES 6-7. Tellina (Moerella?) verdevilla Gardner, n. sp. (p. 97).

6. Interior of paratype, a right valve (U. S. Nat. Mus. 325596) from 6 miles below Greenville, Pitt County, N. C.; height 15.0 

millimeters; width 21.0 millimeters.

7. Exterior of holotype, a right valve (U. S. Nat. Mus. 325596) from 6 miles below Greenville, Pitt County, N. C.; height 13.8

millimeters; width 20.0 millimeters. 

FIGURE 8. Macoma cookei Gardner, n. sp. (p. 100). Interior of holotype, a right valve (U. S. Nat. Mus. 325592) from Yorktown;

York River, Va.; height 28.0 millimeters: width 34.3 millimeters. 

FIGURES 9-10. Macoma virginiana (Conrad) (p. 98). A right valve (U. S. Nat. Mus. 325594) from 1 mile northeast of Suffolk, Va.,

height 12.3 millimeters; width 19.8 millimeters. 

9. Exterior, X 2. 

10. Interior, X 2.

FIGURE 11. Macoma cookei Gardner, n. sp. (p. 100). Exterior of holotype.

FIGURES 12-15. Abra aequalis (Say) (p. 104). A right and a left valve of different individuals (U. S. Nat. Mus. 325585) from half 

to three-quarters of a mile above Edenhouse Point, Chowan River, N. C.

12. Exterior of left valve; height 10.5 millimeters; width 12.0 millimeters.

13. Interior of left valve shown in figure 12.

14. Interior of right valve; height 10.6 millimeters; width 12.0 millimeters.

15. Exterior of right valve shown in figure 14.

FIGURES 16-17. Semele subovata alia Gardner n. subsp. (p. 101). Holotype, the right and left valves of a single individual (U. S. Nat. 

Mus. 325582) from 2 miles northeast of Lizzie, Greene County, N. C.; height 21.0 millimeters; width 26.3 millimeters.

16. Interior of right valve of holotype, X 2.

17. Exterior of left valve of holotype, X 2.

FIGURES 18-21. Semele (Semelina) nuculoides (Conrad) Dall (p. 102). The right and left valves of different individuals (U. S. Nat. 

Mus. 325581) from Neills Eddy Landing, Cape Fear River, N. C.

18. Exterior of left vialve; height 4.0 millimeters; width 5.6 millimeters.

19. Interior of left valve shown in figure 18.

20. Interior of right valve; height 3.8 millimeters; width 5.6 millimeters.

21. Exterior of right valve shown in figure 20. 

FIGURE 22. Macoma virginiana conradi Dall (p. 99). Exterior of holotype, a right valve (U.'S. Nat. Mus. 144475) from Yorktcwn,

York River, Va.; height 14.0 millimeters; width 21.7 millimeters. (After Dall.) 

FIGURES 23-24. Abra subreflexa Conrad (p. 103).

23. Interior of right valve (U. S. Nat. Mus. 325584) from Colerain Landing, Chowan River, N. C.; height 5.6 millimeters; width 

10.4 millimeters.

24. Exterior of right valve shown in figure 23.

FIGURES 25-26. Abra aequalis deUoidea Gardner, n. subsp. (p. 104). Cotypes, a right and a left valve of different individuals (U. S. 

Nat. Mus. 325586) from 2 miles below Lumberton, Robeson County, N. C.

25. Interior of right valve; height 11.2 millimeters; width 11.4 millimeters.

26. Exterior of left valve; height 11.1 millimeters; width 11.9 millimeters. 

FIGURES 27-28. Semele bellastriata (Conrad) (p. 102).

27. Interior of right valve (U. S. Nat. Mus. 325583) from Neills Eddy Landing, Cape Fear River, N. C.; height 13.2 millimeters; 

width 18.3 millimeters.

28. Exterior of right valve shown in figure 27. 

FIGURE 29. Donax aequilibrata Dall (p. 106). Exterior of holotype, a right valve (U. S. Nat. Mus. 108450) from Mrs. Guion's marl

pit, Cape Fear River, near Cronly, N. C.; height 8.5 millimeters; width 17.9 millimeters. (After Dall.) 

FIGURES 30-31. Abra subreflexa Conrad (p. 103).

30. Interior of left valve (U. S. Nat. Mus. 325584) from Colerain Landing, Chowan River, N. C.; height 9.0 millimeters; width 

15.6 millimeters.

31. Exterior of left valve shown in figure 30. 

FIGURES 32-33. Semele bellastriata (Conrad) (p. 102).

32. Interior of left valve (U. S. Nat. Mus. 325583) from Neills Eddy Landing, Cape Fear River, N. C.; height 14.5 millimeters; 

width 19.0 millimeters.

33. Exterior of left valve shown in figure 32.

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GEOLOGICAL SUEVET PKOFESSIONAL PAPER 199 PLATE 18
PLATE 18

FIGURE 1. Spisula (Mactromeris) bowlerensis Gardner, n. sp. (p. 112). Holotype, the right and left valves of a single individual (U. S.

Nat. Mus. 498201) from 1% miles below Bowlers Wharf, Rappahannock River, Va.; height 53.0 millimeters; width

70.0 millimeters. Interior of left valve of holotype. 

FIGURES 2-4. Spisula (Hemimactra) rappahannockensis Gardner, n. sp. (p. 110).

2. Exterior of holotype, a right valve (U. S. Nat. Mus. 325601) from 1 to 2 miles below Bowlers Wharf, Rappahannock River, 

Va.; height 21.0 millimeters; width 31.5 millimeters.

3. Exterior of paratype, a left valve (U. S. Nat. Mus. 325600) from Union Mills, 1% miles south of Farnham, Richmond County, 

Va.; height 15.0 millimeters; width 23.0 millimeters.

4. Interior of holotype shown in figure 2.

FIGURE 5. Spisula (Mactromeris) bowlerensis Gardner, n. sp. (p. 112). Exterior of right valve of holotype the left valve of which is 

shown in figure 1.

FIGURE 6. Labiosa (Raeta) alta (Conrad) (p. 109). Hinge plate of left valve: a, anterior lamina; b, cardinal tooth with one arm projecting over the chondrophore; c, ligament scar with septum below it; /, anterior lamina. (After Ball.)

FIGURE 7. Spisula (Hemimactra) rappahannockensis Gardner, n. sp. (p. 110). Hinge plate of a left valve (U. S. Nat. Mus. 325601) 

from 1 to 2 miles below Bowlers Wharf, Rappahannock River, Va., X 3.

FIGURE 8. Mesodesma spatha Gardner, n. sp. (p. 115). Hinge of holotype, a right valve (U. S. Nat. Mus. 325591) from 1 mile northeast of Suffolk, Va., X 10.

FIGURES 9-11. Mactra (Mactrotoma) fragilis Gmelin (p. 109).

9. Hinge plate of left valve: a, Posterior lamina; b, ligamentary scar with septum below it; c, spur, roofin the pit; d, cardinal 

tooth with e, accessory lamella, and /, anterior lamina. (After Dall.)

10. Right valve from below, showing the profile of the hinge teeth: a, Anterior ventral lamina, and b, anterior dorsal lamina; 

c, accessory lamella of right cardinal tooth, d, anterior arm, and e, posterior arm of same; the space between the 

teeth a, c, d, e, and the edge of the chondrophore is the ventral sinus, that between a and b is the anterior sinus; 

/, septum between the ligament (attached to the shell at g) and the resilium; h and i, ventral and dorsal posterior 

laminae, respectively. (After Dall.)

11. Hinge plate of right valve: a, Anterior dorsal lamina; b, accessory lamella of right cardinal, c, anterior arm (i, posterior arm)

of same; d, septum between the resilium and ligament; e, ligamentary scar; /, anterior ventral lamina. (After

Dall.) 

FIGURE 12. Mesodesma spatha Gardner, n. sp. (p. 115). Interior of holotype, a right valve (U. S. Nat. Mus. 325591) from 1 mile

northeast of Suffolk, Va.; height 6.4 millimeters; width 10.3 millimeters. 

FIGURE 13. Mactra (Mactrotoma) fragilis Gmelin (p. 109). Profile of hinge plate of left valve: a, Anterior lamina; b, accessory lamella;

c, cardinal tooth; d, septum; e, posterior lamina. 

FIGURE 14. Mactra (Mactrotoma) fragilis precursor Gardner, n. subsp. (p. 109). Holotype, a left valve (U. S. Nat. Mus. 325593)

from Neills Eddy Landing, Cape Fear River, N. C.; height 79.0 millimeters; width 121.0 millimeters.

163
PLATE 19

FIGUEES 1-2. Macrocallista reposta (Conrad) (p. 123). A left valve (U. S. Nat. Mus. 325575) from 2 miles below Lumberton, Robeson 

County, N, C.; height 50.0 millimeters; width 85.0 ± millimeters.

1. Interior of left valve.

2. Exterior of left valve.

FiGtiKE 3. Macrocallista reposta (Conrad) (p. 123). Interior of right valve (U. S. Nat. Mus. 325577) from 4 to 5 miles below Lumberton, Robeson County, N. C.; height 42.5 millimeters; width 62.8 millimeters.

FIGUKE 4. Chione (Chione) cortinaria (Rogers and Rogers) (p. 127). Exterior of left valve (U. S. Nat. Mus. 146126) from Grove Wharf, 

James River, Va.; height 23.5 millimeters; width 26.5 millimeters X 1}£.

FIGURE 5. Macrocallista reposta (Conrad) (p. 123). Exterior of right valve shown in figure 3.

FIGURE 6. Macrocallista (Coslacallista') emmonsi Gardner, n. sp. (p. 123). Interior of holotype, a left valve (U. S. Nat. Mus. 107834 

from Natural Well(?), Duplin County, N. C.; height 43.0 millimeters; width 56.5 millimeters.

FIGURES 7-8. Callocardia (Agriopoma) chioneformis Gardner, n. sp. (p. 126).

7. Paratype, a right valve (U. S. Nat. Mus. 325564) from Wilmington, N. C.; height 17.5 millimeters; width 20.5 millimeters X l>i

8. Holotype, a left valve (U. S. Nat. Mus. 325564), from Wilmington, N. C.; height 26.5 millimeters; width 31.0 millimeters. 

FIGURE 9. Macrocallista (Costacallista) emmonsi Gardner, n. sp. (p. 123). Exterior of holotype shown in figure 6. 

FIGURES 10-11. Chione (Chamelea) cialli Olsson (p. 129). Topotypes, a right and a left valve (U. S. Nat. Mus. 325529) from lower 

layer at Claremont Wharf, James River, Va.

10. Interior of right valve; height 20.0 millimeters; width 22.3 millimeters.

11. Exterior of left valve; height 19.5 millimeters; width 21.0 millimeters.

FIGURES 12-13. Chione (Chione} grus (Holmes) (p. 128). A right and a left valve (U. S. Nat. Mus. 325565) from Neills Eddy Landing, 

Cape Fear River, N. C.

12. Exterior of right valve; height 6.8 millimeters; width 9.5 millimeters.

13. Exterior of left valve of another individual; height 5.0 millimeters; width 7.5 millimeters. 

FIGURE 14. Gemma magna insulcata Gardner, n. subsp. (p. 137). Exterior of paratype, a left valve (U. S. Nat. Mus. 325570) from

Walkers Bluff, Cape Fear River, N. C.; height 3.4 millimeters; width 4.1 millimeters. 

FIGURES 15-17. Gemma magna virginiana Dall (p. 136). Cotypes, a right and a left valve of different individuals (U. S. Nat. Mus.

144633) from Yorktown, Va.

15. Interior of right cotype; height 3.4 millimeters: width 3.5 millimeters.

16. Exterior of right cotype shown in figure 15.

17. Interior of left cotype; height 3.7 millimeters; width 4.1 millimeters. 

FIGURE 18. Gemma magna virginiana Dall (p. 136). Interior of topotype, a left valve (U. S. Nat. Mus. 325571) from Yorktown, Va.;

height 3.3 millimeters; width 3.6 millimeters. 

FIGURE 19. Gemma magna majorina Gardner, n. subsp. (p. 136). Exterior of right cotype (U. S. Nat. Mus. 325566) from 1 mile

east of Lizzie, Greene County, N. C.; height 5.6 millimeters: width 6.6 millimeters. 

FIGURES 20-21. Chione (Chione) grus (Holmes) (p. 128).

20. Interior of right valve shown in figure 12.

21. Interior of left valve shown in figure 13. 

FIGURE 22. Gemma magna insulcata Gardner, n. subsp. (p. 137). Interior of holotype, a right valve (U. S. Nat. Mus. 325567) from

Neills Eddy Landing, Cape Fear River, N. C.; height 4.5 millimeters; width 5.2 millimeters. 

FIGURES 23-24. Gemma cravenensis Gardner, n. sp. (p. 137). Holotype, the right and left valves of a single individual (U. S. Nat.

Mus. 325569) from Rock Landing, Craven County, N. C.; height 3.7 millimeters; width 4.6 millimeters.

23. Interior of right valve, X 4.

24. Exterior of left valve, X 4. 

FIGURE 25-26. Gemma magna virginiana Dall (p. 136).

25. Interior of cotype, a left valve (U. S. Nat. Mus. 144633) from Yorktown, Va.; height 3.0 millimeters; width 3.2 millimeters.

26. Interior of cotype, aright valve (U. S. Nat. Mus. 144633) from Yorktown, Va.; height 3.2 millimeters; width3.3 millimeters. 

FIGURE 27. Gemma magna mojorina Gardner, n. subsp. (p. 136). Interior of left cotype (U. S. Nat. Mus. 325566) from 1 mile east of

Lizzie, Greene County, N. C.; height 6.6 millimeters; width 7.3 millimeters. 

FIGURES 28-29. Callocardia (Agriopoma) castoriana Gardner, n. sp. (p. 126). Holotype, a right valve (U. S. Nat. Mus. 325563) from

1 mile north of Castoria, Greene County, N. C.; height 39.0 millimeters; width 49.0 millimeters; convexity 14.2

millimeters.

28. Profile of holotype from front.

29. Interior of holotype. 

FIGURE 30. Crassinella lunulata (Conrad) (p. 62). Exterior of a left valve (U. S. Nat. Mus. 6123) from Natural Well, Duplin

County, N. C.; height 5.9 millimeters; width 6.7 millimeters. (After Dall.) 

FIGURES 31-32 Gemma verdevilla Gardner, n. sp. (p. 138). Holotype, the right and left valves of a single individual (U. S. Nat. Mus.

325568) from 8 to 9 miles southeast of Greenville, Pitt County, N. C.; height 2.6 millimeters; width 2.6 millimeters.

31. Interior of right valve, X 4.

32. Exterior of left valve, X 4.

FIGURE 33. Callocardia (Agriopoma) sayana (Conrad) (p. 124). Interior of a left valve (U. S. Nat. Mus. 143732) from the Choptank River, a quarter to half a mile below Barkers Landing, Talbot County, Md.; height 40.0 millimeters; width 

45.0 millimeters. (After Dall.) 

164
GEOLOGICAL SURVEY PEOFESSIONAL PAPER 199 PLATE 19

33

PELECYPODS.
GEOLOGICAL SURVEY PROFESSIONAL PAPEE 199 PLATE 20

PELECYPODS.
PLATE 20

FIGURES 1-2. Venus (Mercenarid) campechiensis carolinensis Conrad (p. 132). A left valve (U. S. Nat. Mus. 325573) from Walkers 

Bluff, Cape Fear River, N. C.; height 119.0 millimeters; width 153.0 millimeters.

1. Interior of left valve, X 0.95.

2. Exterior of left valve, X 0.95.

165
PLATE 21

FIGURES 1-3. Venus (Mercenaries) berryi Gardner, n. sp. (p. 133). Holotype, the right and left valves of a single individual (U. S. 

Nat. Mus. 325574) from 2}£ to 3 miles below Bowlers Wharf, Va.; height 57.0 millimeters; width 62.5 millimeters; 

diameter 37.6 millimeters.

1. Interior of left valve.

2. Dorsal view of double valves.

3. Interior of right valve. 

FIGURES 4-6. Venus (Mercenaries) berryi Gardner, n. sp. (p. 133).

4. Exterior of adult paratype, a right valve (U. S. Nat. Mus. 325574) from 2}£ to 3 miles below Bowlers Wharf, Va.; figured to 

show fusing of concentric lamellae; height 46.5 millimeters; width 54.0 millimeters.

5. Exterior of adolescent paratype, a right valve (U. S. Nat. Mus. 325576) from 1 to 2 miles below Bowlers Wharf, Essex County, 

Va.; height 8.0 millimeters; width 8.5 millimeters.

6. Exterior of left valve of holotype shown in figure 1.

FIGURES 7-8. Venus (Mercenaria) plena nucea Ball (p. 134). Holotype, a right valve (U. S. Nat. Mus. 163418) from Bellefield, York 

River, Va.; height 30.0 millimeters; width 33.0 millimeters.

7. Exterior of holotype.

8. Interior of holotype.

FIGURE 9. Venus (Mercenaria) plena inflala Ball (p. 134). Exterior of holotype, a right valve (U. S. Nat. Mus. 163419) from Bellefield, York River, Va.; height 51.0 millimeters; width 60.0 millimeters. 

FIGURE 10. Venus (Mercenaria) mercenaria notata Say (p. 130). Exterior of left valve (U. S. Nat. Mus. 46867), Recent on the east

coast of Florida; height 60.0 millimeters; width 76.0 millimeters. % 

FIGURE 11. Venus (Mercenaria) campechiensis tridacnoides (Lamarck) (p. 132). Profile of double valves from the Wagner Free

Institute of Science of Philadelphia; diameter 100.0 millimeters. 

166
GEOLOGICAL SURVEY PROFESSIONAL PAPER 199 PLATE 21

10 11

PELECYPODS.
GEOLOGICAL SURVEY PKOFESSIONAL PAPER 169 PLATE 22
PLATE 22

FIGURES 1-4. Tagelus gibbus (Spengler) (p. 107).

1. Exterior of left valve from Wailes Bluff (near Cornfield Harbor), St. Marys County, Md. (After Clark.)

2. Exterior of right valve from Wailes Bluff (near Cornfield Harbor), St. Marys County, Md. (After Clark.)

3. Interior of left valve shown in figure 1. (After Clark.)

4. Interior of right valve shown in figure 2. (After Clark.) 

FIGURE 5. Tagelus gibbus carolinensis (Conrad) (p. 108). Exterior of left valve (U. S. Nat. Mus. 145293) from Wilmington, N. C.;

height 23.0 millimeters; width 69 millimeters. 

FIGURES 6-7. Spisula (Hemimactra) similis (Say) (p. 111). A Recent shell is figured (U. S. Nat. Mus. 95569).

6. Interior of left valve X 1.

7. Exterior of right valve X 1. 

FIGURE 8. Mya arenaria Linnaeus (p. 138). Interior of left valve from Wailes Bluff (near Cornfield Harbor), St. Marys County

Md., X 5/6. (After Clark.)

FIGURE 9. Barnea (Scobinopholas) arcuata (Conrad) (p. 141). Exterior of right valve and hinge of left valve of holotype from Suffolk, Va. (After Conrad.)

FIGURE 10. Spisula (Mactromeris) duplinensis Dall (p. 112). Interior of holotype, a right valve (U. S. Nat. Mus. 153784) from 

Natural Well, Duplin County, N. C.; height 42.0± millimeters; width 58.0± millimeters. (After Dall.)

167
PLATE 23

FIGURES 1-2. Donax fossor Say (p. 106).

1. Exterior of left valve (U. S. Nat. Mus. 325587) from 4 miles south of Elizabethtown, 1ST. C.; height 4.9 millimeters; width 

9.0 millimeters.

2. Exterior of right valve (U. S. Nat. Mus. 325587) from 4 miles south of Elizabethtown, N. C.; height 3.3 millimeters; width

5.0 millimeters.

FIGURES 3-4. Donax emmonsi preaeqmlibrata Gardner, n. subsp. (p. 105). Holotype, the righ! and left valves of a single individual 

(U. S. Nat. Mus. 325590) from 2 miles below Lumberton, Robeson County, N. C.; height 8.0 millimeters; width 

14.4 millimeters.

3. Interior of left valve of holotype, X 3.

4. Exterior of right valve of holotype, X 3.

FIGURE 5. Donax emmonsi Dall (p. 105). Exterior of holotype, a right valve (U. S. Nat. Mus. 108447) from Mrs. Guion's marlpit near Cronly, Cape Fear River, N. C.; height 6.7 millimeters; width 10.2 millimeters. (After Dall.) 

FIGURES 6-7. Donax chuckatuckensis Gardner, n. sp. (p. 106).

6. Exterior of holotype, a left valve (U. S. Nat. Mus. 325589) from a quarter of a mile north of Chuckatuck, Nansemond County 

Va.; height 3.6 millimeters; width 6.2 millimeters.

7. Interior of holotype, X 3. 

FIGURES 8-9. Spisula (Hemimactra) modicdla (Conrad) (p. 111).

8. Interior of immature left valve (U. S. Nat. Mus. 325598) from 1 mile northeast of Suffolk, Va.; height 7.9 millimeters; width 

11.7 millimeters.

9. Exterior of valve shown in figure 8. 

FIGURES 10-11. Donax fossor Say (p. 106).

10. Interior of valve shown in figure 1.

11. Interior of valve shown in figure 2.

FIGURES 12-15. Mulinia congesta (Conrad) (p. 113). The right and left valves of two individuals (U. S. Nat. Mus. 325602) from 

1 mile northeast of Suffolk, Va.

12. Exterior of left valve; height 15.3 millimeters; width 22.0 millimeters.

13. Interior of left valve shown in figure 12.

14. Interior of right valve; height 15.5 millimeters; width 21.0 millimeters.

15. Exterior of right valve shown in figure 14. 

FIGURES lfr-17. Spisvla (Hemimactra) modicella alta Gardner, n. subsp. (p. 111).

16. Exterior of holotype, a right valve (U. S. Nat. Mus. 325599) from Rock Landing, N. C.; height 13.2 millimeters; width 

18.0 millimeters.

17. Interior of holotype. 

FIGURES 18-19. Spisula (Hemimactra') modicella (Conrad) (p. 111).

18. Interior of a right valve (U. S. Nat. Mus. 325598) from 1 mile northeast of Suffolk, Va.; height 11.2 millimeters; width 

15.0 millimeters, X 2.

19. Exterior of right valve shown in figure 18. 

FIGURE 20. Erv^lia lata Dall (p. 115). Interior of holotype, a right valve (U. S. Nat. Mus. 115054) from Natural Well, Duplin County,

N. C.; height 3.6 millimeters; width 5.2 millimeters. (After Dall.)

FIGURES 21-24. Mulinia congesla (Conrad) (p. 113). A right and a left valve of different individuals (U. S. Nal. Mus. 325603) 

from \l/i miles west of Smithfield, Va.

21. Exterior of left valve; height 24.5 millimeters; width 26.5 millimeters.

22. Interior of left valve shown in figure 21.

23. Interior of right valve; height 23.0 millimeters; width 25.5 millimeters.

24. Exterior of right valve shown in figure 23. 

FIGURE 25. Ermlia lata radiata Gardner, n. subsp. (p. 116). Interior of holotype, a right valve (U. S. Nat. Mus. 325597) from Neills

Eddy Landing, Cape Fear River, N. C.; height 2.6 millimeters; width 4.0 millimeters. 

FIGURE 26. Corbula (Caryocorbula?) scutata Gardner, n. sp. (p. 140). Exterior of right valve of holotype, (U. S. Nat. Mus. 497058)

from Shell Creek, De Soto County, Fla.; height 6.4 millimeters; width 9.0 millimeters X 3. 

FIGURES 27-28. Corbula (Caryocorbula) conradi Gardner, n. sp. (p. 139). Holotype, the right and left valves of the same individual

(U. S. Nat. Mus. 325605) from 15}£ miles above Bells Bridge, Edgecombe County, N. C.; height of closed valves

6.7 millimeters; width 11.0 millimeters.

27. Exterior of left valve, X 3.

28. Exterior of right valve, X 3. 

FIGURE 29. Ervilia lata radiata Gardner, n. subsp. (p. 116). Exterior of paratype, a left valve (U. S. Nat. Mus. 325597) from Neills

Eddy Landing, Cape Fear River, N. C.; height 2.6 millimeters; width 4.2 millimeters. 

FIGURES 30-32. Corbula (Caryocorbula?) scutata Gardner, n. sp. (p. 140).

30. Interior of right valve of holotype shown in figure 26.

31. Interior of left valve of holotype shown in figure 26.

32. Double valves of holotype shown in figure 26 viewed from the rear, diameter, 5.7 millimeters.

FIGURES 33-34. Corbula (Caryocorbula) conradi retusa Gardner, n. subsp. (p. 140). Holotype, the right and left valves of a single 

individual (U. S. Nat. Mus. 325604) from half to three-quarters of a mile below Edenhouse Point, Bertie County, 

N. C.; height 5.0 millimeters; width 7.7 millimeters.

33. Exterior of right valve, X 4.

34. Exterior of left valve, X 4. 

FIGURE 35. Kuphus calamus (H. C. Lea) (p. 143). Fragment of tube (U. S. Nat. Mus. 325608) from Baileys Creek, James River,

Va.; outside diameter of tube 11.6 millimeters; inside diameter of tube 7.0 millimeters. 

FIGURES 36-37. Zirfaea rhomboidea (H. C. Lea) (p. 142).

36. Exterior of left valve of holotype (Acad. Nat. Sci., Philadelphia 1583), X 6.

37. Interior of right valve of holotype, X 6. 

FIGURE 38. Martesia cuneiformis (Say) (p. 143). Exterior of left valve (U. S. Nat. Mus. 46850), Recent from the east coast of

Florida, height 9.6 millimeters; width 17.5 millimeters,X2. 

FIGURE 39. Isocardia fraterna Carolina Dall (p. 67). Interior of paratype (U. S. Nat. Mus. 146166) from Grove Wharf, James

River, Va.; height 67.0 millimeters; width 84.0 millimeters; convexity 28.5 millimeters. (After Dall.) 

FIGURE 40. Solen viridis Say (p. 108). Interior of double valves of specimen (U. S. Nat. Mus. 153356), Recent from Smiths Island.

Va.; height 7.5 millimeters; width 35.5 millimeters,X2

168
PROFESSIONAL PAPER 199 PLATE 23

35

PELECYPODS.

INDEX

abbreviata, Cardita________________________________ 71

Qlans (Pteromeris) perplana-——____._____________ 72-73, pi. 13

Pteromeris perplana___________________^_________ 15

Venericardia perplana______________________._____ 9

Abra.-.——-———......—...———————__._.__...._.... 103-105

aeqnalls-.———.————..——._.___.____....... 16,104, pi. 17

deltoidea——.____—..____•—-___..___..... 16,104-105, pi. 17

bella.......__....___________________________._ 102

nuculiformis__________________________________ 104 

nuculoides-.—-———_—__—„__..______...________ 102 

ovalis-..—_____..__—_________________________ 101 

subreflexa-—........!...—.........._—————————- 16,103-104, pi. 17

(Amphidesma) subovata-———.-——————__—__________ 101

Abstract._—.....——__„________.________________ 1

acetabulum, Artemis. ______________________________ 120 

Doslnia——...——._—___..____.__:__.—.......—.. 10,120

Dosinla (Dosinidia).____.........____.__._____ 7,15,120-122, pi. 11

Acteocina_..__..„—_—________________________ 8 

canalieulata._——-._....._______.________________ 12

Actinobolus tridentata,_____________________________. 70 

aculeata, Anomia__.___...___________________.__.__.. 41 

acuminata, Pholas———...——........__—____________.__ 141

acuta, Mya.__________________________________ 138, pi. 22

Nuculana.-.__________________________________ 9,12

acutilaqueatum, Cardlum_.__________________________ 10,90

Cardium (Cerastoderma)-—_______________________ 15,90

Cerastoderma--_________—_________________ 90-91, pi. 16

adamsi, Seila._._______________________________ 8,12

advcrsarius, Conus..———..—..__——___—_______________ 8

aequalis, Abra___„___.___._________________ 16,104, pi. 17

Amphidesma———————————————_—__—___.„._____ 104

aequilibrata, Donax.........———_——__...___________„ 106,pi. 17

Aequipecten.—__—_._._________________________ 35-37 

africana, Dosinia--——...—————————_——_—..._„______ 120 

Agriopoma---.~__——_—___—_____________,______ 124-127 

alabamicnsis, Corbula____________________.,_________ 139 

albidus, Pectunculus————————.——__—__...___——__.-__ 122 

Alectrionperalta--..——.__.________________________ 13 

Allgena-—->—..——----—---——————————— —— ————— 87-88

chowanettsis—_—..__._________________...___.. 15,87, pi 14

rhomboidea.__——_—___.________________ 15,87-88, pi. 14

striata_____—___._________________________ 87

alta, Semele subovata___________________________ 16,101, pi. 17

Spisula (Hemimactra) modicella..——————„......:.-—.„ 16, 111, pi. 23

alticostnta, Turritella-_-__..._______.______-__—.___ 9,10,11 

altilis, Ptycbosalpinx--_____-___________________.____ 10 

americana, Glycymeris.-l—.—.....——.._—..__....__— 10,13,27-28,pi. 1

americanus. Pectunculus.-_..___—___._______________ 27 

Americardia.———————-———...——-._—________..,__-.--. • 93 

Amphidesma aequalis..--__....__...__.________________ 104

bellastriata.—.........._....._....__.___.__........... - 102, pi. 17

cancellata_____.____________,____________,___- 102 

constricta____-____.___.____________________- 83 

nuculoides-.__—___.._._„___..._______________ 102 

subovata---____________________________.____. 100 

subreflexa----_-.—————__—.....—___....__..—....—. 103

Amusium.-.-____-____.___—____________.______ 39

mortoni..-________.________________________ 39, pi. 8

Anachis milleri.___.___.___...__..______________ 12

Anadara..—_____—.__—.„_—__——__.____.___.__ 23-26

eallicestosa....—____.______________________ 24, pi. 3

callicestosa wilsoni-——...———..—-.-.._———_—.._——.- 24-25, pi. 3 

carolinensis_______________________________ 25-26, pi. 2 

lienosa..-------„———.——-----——.———_-——__„.. —. 23-24,pi.2

magnoliana.___-__...____-___—__-____..___- 25, pi. 3

protraeta--._______-______________________ 24, pis. 2,3

(Cunearca) scalaris————————————————————-—————— 26, pi. 2

Anatina antiqua-__—.__——„...———.——__,—__—--_—— 42

leana,.--——-.-————————————————.—————-———-——— 42

Angulus polita.___..___—__—_.....___....__—-.__—— 96

angustior, Cbama...-———_——_——....———..———...——„——— 107

401033—43———14

Page

anodonta, Pbacoides——————————————————'.——————————— 9

Phacoides (Pseudomiltha)_______————————————————.— 6

anomala, Mysella__—————————————————————————————— - 85

Anomia aculeata_——————————————————————————————— 41

zealandiea._..-.-.--————_————————————..———*————-. 41

antiqua, Anatina-——————————————— ——— ————————————,—— 42

Periploma.-—————————————————————————————————— . 42

Periploma (Cochtodesma).__—_„.——__————————————.. 42

antiquata, Area-.———,—————— ——————————————————————— ---- , 23

antiquatum, Cochlodesma.-————————.—————————— -——————-— 42 

atata, Astarte..--—-—_......—..__....._....—.... 9,11,14,55-56,pi. 12

Cardita——————————————————————————— 9,10

Carditamera_ ———————————————————————————————. 15 

Cypricardia.---------——————.——.——-———— ——-—... 6S

Area__.______________-_____———————————————__ 22

antiquata..— ———————————— —————————— ——— _--... ————.. 23

callicestosa-..-- —————————— —————————————— — —— ----—— 24

carolinensis-————————————————1———————————-——————— 25 

glycymeris--..—————— ———————————————————————————— 26 

hians- —________-___----__——,———————————-——-__ 22

idonea- —------—————-————————-—————-—————..— 6,7,13

improcera------ — —— —— --- —— — — --————————-———————— 8,12

incongrua__——— —— ———— -------------—————,———- ——— —— 26

lienosa-_————————————————————————————...————— 24, 

noae__ ——.- — —— ------ ————— —————— ————..-—-——.. — -. 22

nucleus.——— ———————————————————— ————... —— —— - 19. 

propatula_.- ———————————————————————— ————— - — —— 22 

protraeta---————————————————————————'—'———————— 24 

scalaris.-- ———— ————————————————————————————— — 26 

staminea.---- ——————————————————— -——— ————— -.-- 5.

virginiae_.. —— ---.—————.. —————— — — ——— -- —— ---------- 7,13

sp--_.———————————————————————————————————————— 6 

(Aaadara) callicestosa.-.___.____—__——__.-._______ 24 

lienosa__.._—————.————.—————————————..—__ 23 

(Anomalocardia) protraeta—_...——————.———_—_______ 24 

(Barbatia) centenaria———__—————————————..—-------___ 6

(Cunearca) scalaris__.____———.-————————..———.....___ 26,

(Noetia)incUe———————————————-—- — — - 9,10,13

(Scapharea) scalaris———————————————————————-----___ 14

lienosa__.___——————————————————.——_.___ 14

eallieestosa--.--_——.————— ————————————..-.-_... 14

earolinensis——————————————————————————_„___ 14

(Striarca) centenaria--. —— -—————_——————————_______ 9,10

arctica, Yoldia.— ——— ———— „——————————————————-——__ 21

arcuata, Barnea (Scobina)——————————————————————————_ 141

Barnea (Scobinopholas)-——----------——........—.J——_ 16,141-142,pi. 22

arcuata, Pholas __„._.—————————————————————'-.... ...._ 141

arenaria, Mya......—,--.....— ———————————— 138-139,pi. 22

arenosa, Pandora___—„——. ————.———————————_____ 45

Pandora (Kennerlia)______———..———...——__..__.. 14,46,pi. 10

Artemes transversus—————————————————————————— '.. ,___ 122

Artemis acetabulum—. __——__—————————————______ 120

concentrica._————————————... ——————————— ------___ 122

elegans-..——...——......——.——.-.———-——...——————....... 123

Asapbis centenaria,--------- — — —'-———————————————_.___ 119

Ashtarotha.___———-———————————————————————„„__ 56

Astarte_______.__.-———-———————————————————_____ 51-61

arata..- ———— ————————————————.. ———_ 9,11,14,55-56

beTla.—— ——————————————————————..... 61

1 berryi——— - ——-——-————————————— 12,14,56,pl. 12

coheni—_-„--—-------- — ---———————-----———.——... 9,53,pi. 12

compsonema- _ -____——__...——————..——__—______ 61 

concentrica......___-___.„"—.-———__.___...___.'..'__ 59,61.

bella-.-.....- ————— ——— ———————————— ———— 60-61

exaltata.———————————————————— 6,7,9,14,52, pi. ^12.

hertfordensis...-.—.----- — -——--———————— 11,14,53,54, pi. 12

llneolata—____._____...-___—________________ 61 

lunulata_.--...._-----_.....———.——..__—__________ 62

obruta—___———————_—————-•—————_.'..——'__'.__ 5 

hertfordensis meherrinensis__—___—___.________ 14,54, pi. 12 

aff. A. obruta—_______________________._______ 6
170 INDEX

Page 

Astarte—Continued.

perplana.—.———.——_.__.....——....—.......—................ 7,13

roanokensis-_.<.__......._.__„—..._____...__..... 14,53. pi. 12

stephensoni_____________________________ 14,54-55, pi. 12 

symmetrica....__.....—.___...——_....____ 10,13,14,51-52, pi. 12

undulata—_________________________________ 57

vaginulata___._________________._-_________ 58

viclna————.....———..____...__________________ 52

(Ashtarotha) concentrica. —.___._-........--.-.._ 10,12,14,59-60,pi. 12

concentrica bella__•______________________ 14,60,pl. 12 

conradi.—...—......._................................ 14,60, pi. 12

griftonensis——————____—.____.___.___...... 14,57, pi. 12

rappahannoekensis_______'._____________.. 14,56-57, pi. 12 

undulata_......__..........._„........—........ 9,14,57-58, pi. 12

deltoidea.__...___..__.................... 6,7,9,11,14,59, pi. 12

vaginulata—_____.__.______...._ 6,7,9,14,58-59, pi. 12

Astrangia lineata_________._______________________ 9 

athleta, Chione_....._______._..._._______......._...--.. 6

attenuatum, Dentalium...,____ _____________________ _ 7,11 

australis, Rochefortia_______________________________ 85

Barbatia_________________________________'_ ____ 22-23

(Granoarca) propatula____________.____________ 22-23, pi. 2

Barnea.................._______.___..................I........._ 141-142

spinosa.........._....__....__..._,______.____.......... 141

(Scobina) arcuata_________________________ _____ 141 

(Scobinopholas) arcuata............x..._____..__...... 16,141-142, pi. 22

bella, Abra..___________________________________ 102 

Astarte_.________________________________ 61

concentrica.-__...........__——________.____..__.. 60-61

(Ashtarotha) concentrica.....-.---.-._____......_... 14,59,60, pi. 12

Marginella..____________________________________ 8,12 

Semele..______L.........................................._____ 101

beltestriata, Amphidesma...........-...—-.—.......................__ 102, pi. 17

", 8emele—......................................................... 16,102, pi. 17

berryi, Astarte-......———————————————————— 12,14,56, pi. 12

. Venus (Mercenaria).._._..............._......__..._ 15,133-134, pi. 21

bertiensis. Pecten eboreus____ .________. ______________ 12 

bicarinata, Pandora (Kennerlia)_________._..._......_......... 45

bilirata, Pandora._._.___.._____...........I..........._.._ 45

hladenensis, Bornia______________.-____-..___..._ 15,83, pi. 14 

Mysolla—_-_-_______.________________.____._________..____._.__'___ 15,86, pi. 14

Bornia.—.......__....___.___________._..___........___ 82

bladenensis.......______..............._._._.__...._ 15,83, pi. 14

corbuloides..____.______._.__..".....__..___...__ 82

triangula—__._............................................... 15,82-83, pi. 14

bowlerensLs, Spisula (Mactromeris)- __________________ 16,112, pi. 18 

Brachidontes.__.______________.________....._._____ 29-30

(Ischadium), recurvus.___________._____._____ 29-30, pi. 1 

Brachydontes hamatus._____________________....___ 29

Bucardia fraterna________________________________. 67

Bulliopsis quadrata________________________________ 6

Busycon canaliculatum__.__________________________ 12

coronatum__..._______________.._________ 13

rugosum................_......—..._..__........_....___ 13

maximum fllosum.____________________1 _____i_____ 13

Cadulus thallus.- _________________________________ 9

Caecum stevensoni.. __________________ _____________ 10

calamus, Kuphus ________________________ 6,9,10,16,143-144, pi. 23

Teredo-.-.--...——. __ .... __ ...........................'...... 143

calcarca, Tellina __ .. ______________________________ 98

calliccstosa, Anadara ______________________________ > 24, pi. 3

Area... _______________________________________ 24

(Anadara) __ .... 

(Scapharca) — - 

Scapharca (Scapharea) . 

Calliostoma humile. 

mitehellL.-

. __ .... — ___ . _ .... _____ . __ 24

. __________ _____ .. 14 

^ ____________________ . 24

13 

9 

phllanthropum..— —— ... ___ ....._ — __ .... — .._...._ _ ... ___ ~ 9,10

" virglhicum.. — _. __________ . _ . __ . __ ...." ____ ... _ ... 10

Callista convexa _______________________ . ________ ... 124 

(Callista) reposta—— ._——.—.. ............... __ . __ ... . ____ ... .. 123

CaHocardia.— ————.———.. __ . _ . ___ ........... ________ 124-127

guttata—— ——...—.— ........... ———————————————— 124

sayana-.. _______ . _______ . __ ........ ____ . __ .„ 10,12

(Agriopoma) castoriana _____ T— —— _______ - ____ 15, 126, pi. 19 

chioneformis—— _ . _ . __ . _ . ___ ... . _____ ... 15, 126-127, pi. 19

sayana ______________________________ 124-126, pi. 19

caloosaensis, Diplodonta..-. — ____ .. —— _ ... ————— ..---.-. —— . 80,pl.l4

calpix, Sportella— . __ ... ________________________ . 15, 84, pi. 14

Tellina(Moerella?)— H— — — — — -— — — .———..—— 16, 98, pi. 17

Page

Calvert formation, description of—————————————————————— 4-5, fig. 1

fossilsin.———————————————————————————————1——— 5

campechiensis, Venus..————————1————————————————————— 132

canah'culata, Acteocina..——.———.—————————————————————— 12

canaliculatum, Busycon———————————————————————————— 12

canaliferum, Fulgur canaliculatum.-.-—————.———————.—————— 8

cancellata, Amphidesma———————————————————————————— 102

Semele——————.———.....—————-———————————————— 102

Venus..———————————————————————————————————— 127 

candidus, Pholas—_.—————————————————————————————r 141 

cardiiformis, Verticordia.——————————————————————-—————— 60 

Gardiolucina———————————————————————————————————— 76-77 

Cardita abbreviata_.——————————————.——1——-—-————— 71 

arata--—————————————-—————————-—————— 9,10

verdevilla——.—————————.—————————————————... 9 

perplana...—————————————————————————————————— 71 

tridentata.——.————.——————————————..... —— 70,71

(Venerieardia> tridentata-___————————————————————— 70 

Carditamera—.........——.——..——...—.—.———————....——— 68-69

arata.._——————————————-—————————————i————— 15 

columbiana..-.—. —... —— — - ———— — - —— — —— — ————— -- 15

verdevilla—..—...__...„.___——__.—....—__._ 15,69, pi. 15

' columbiana-.————.——_——-———————————————— 69, pi. 15

Cardium..._........——..............——.....———————————.» 89

aeutilaqueatum_—————————————————————————————— 10,90 

costatum-———..—————————————————————————————— 89 

eburniferum————————————————————————————————— 91 

edule._—————————————————-————————————,-———— 89 

egmontianum..._——————————————————————————.—— 91 

europaeum.....——————————————————————————————— 93

floridanum...————————————————————————————————— 92 

graniferum—.———————————————————————————————— 93 

humanum——————————————————————————————————— 67 

ingens-——-—————————————-——————————————————— 90 

isocardia.——————————————————————————————————— 91 

laqueatum———————————————————————————.——————— 90 

medium..——————————————————————————————————— 93 

muricatum————————————————————————————————— 92 

norvegicum—————————————————————————————————— 93 

quadrans. —————————————.——- ———.—————————————— 91

quadrigenerium. -.. —— ————... ———————————————,........ 92

sublineatum..———————————————————————————„.„——— 94

taenioplcura————————————————————————————————— 13

venustuni——J————.——...- ————. — — ——————————— 93

virginianum___...——————————————..—.——————————— 7,9,10,91

sp.——————————————————————————————————————— 5

(Cerastoderma) aeutilaqueatum..————————————————————— 15,90

laqueatum_———————————————————————————— 1... 90

virginianum.—————————————————————————————— 15,91

(Fragum) medium.——————————————————————————1—— 93

(Laevicardium) sublineatum.-.—————„_——————.—————— 15,94

(Trachycardium) emmonsii—.———————————————,——————— 92

isocardia—__———————————————————————— 15,91

muricatum...————————————....—————————————— 92

cariboea, Siliquaria.- — ————————————————————————— ———— 107 

cariboeus, Cultellus..————...........——————....—..T ....— 107,108

Planopaea]————————————————————————————————— 107 

Solecurtus——....——————.——————————————————————— 107

Solen——————————————————————————— 107

carinata, Turritella plebeia.——————————————————————————— 7,13

Carolina, Isocardia.-—————————————————————————'—————, 67

Isocardia fraterna—————————————————. 9,11,15,67-68, pis. 11,23

North, Miocene stratigraphy of, summary of__————————————— 2.

Pliocene stratigraphy of, summary of—————————————————— 2-3

carolinense, Dentalium.".———————————————...——————————— 13

carolinensis, Anadara.————————————————-—————————— 25-26, pi. 2

Area—__-__..——-————-—————————-—-—-———— 26

(Scapharca)__————————————————————————————— 14 

Eontia..———...—-————.———-———.———-—————.——.— 12 

Erycina——————...—.....—————————————— 15,81-82, pi. 14

Macorna_—————————————————————————————————— 100 

Mercenaria——————————————————.————-————-———--• 132 

Modiola————————————————————————————— 29

Pandora———————————————————————————————————— 46 

Petricola.------——.................————————————— 118

(Petricolaria)_.__——__-i.——....—.....——.......——- 118

Scapharca (Scapharca)———————:——...———.——————————-—— 25 

Siliquaria————.............———————————...————— 107,108

Tagelus gibbus——.————————————————— 16,107,'lOS, pi. 22

Venus.__——_———————.........————————————— 132

fMereenaria) campechiensis———.—.——.—————————— 15,132,pL20 

carpenteri, Cooperella————...__————„———......—— 15,119-120,pi. 14

Caryatis plionema..._..————..——.— —.....—————,————*~'~ 124

Caryocorbula______........__........—_... ——— ————————— 139
INDEX

Page

eastoriana, Oallocardia (Agriopoma)____________..______ 15,126, pi. 19

centenaria, Area (Barbatia)______________________:___ 6

Area (Striarca)—-_...--___.._—.._____——..._———— 9,10

Asaphis____________________________________ 119 

Petrieola——————————:——_——————————————_ 118,119

Pleiorytis————————————————— ————————— 7,10,119,pi. 15

Cerastoderma_________________________________'_ 89 

acutilaqueatum____________________________90-91, pi. 16 

laqueatum_________________________.______ 90, pi. 16 

virginianum...—.—......_.___.____.___________ 91, pi. 16

Chama—.——...—.._____________________________ 88 

angostior.————————.———...__________________._ 107 

congregata———————————————————————....________ 9,11

cor.__.___„______________________________ 67

eorticosacristella... 

dosta-—...—...——————————————._______........___.......... 120

lazarus____________________________________ 88 

striata—............———....—.—.........__................ 15,88, pi. 13

trapezia.______._____________.._______________ 69

Chamelea.____________________________________ 129-130

Chione___.____________________________________ 127-130

athleta_____._________._______________.____ 6

cortinaria—...————...._•——........_.__.....________ 9,15,127

cribraria._____________________________._._ 128

dallL——.......................————......_............_........ 129

parva___._________________________________ 128 

(Chamelea) dalli...-—————————................ 7,13,15,129-130,pi. 19

(Chione) cortinaria—-.——.———————————————___ 127-128,pi. 19

cribrariai_______________________„_________ 128 

grus-.—...............————...—........................ 128-120, pi. 19

(Timoclea) gras.....—————...._.____....——..........—.... 16,128

chioneformis, Calloeardia (Agriopoma)_______________ 15,126-127, pi. 19

Ohlamys..____________________________________ 31-32

decemnaria________,______________________ 31-32, pi. 5

(Aequipecten) comparilis_____ ___________________ 37, pi. 7

eborea..—.—.....————————.———————____.... 36-37, pi. 7

(Chlamys) decemnaria____ ____________________ _ _ 31

(Lyropecten) ernestsmithi______________________.. 34-35,pi. 6 

jeffersonia..———.——.._......._.__........._____ 32-34,pi. 4

jeffersonia edgecombensis-_____<_____________:_____ 33 

jeffersonia septenaria________________________ 33,34, pi. 4 

madisonia________________________. ____ 32, pis. 4,9 

• peedeensis——————...—......_._.______________36, pi. 6

planicosta————.——————————.—......__,_____.. 34, pi. 9

(Placopecten) clintonia...——.—.„__.____________ 37-38, pi. 6

(Placopecten) marylandica...____________________ 38, pis. 5,6

virginiana......————.—.——.————.———.............. 38-39,pi. 4

(Plagioctenium) comparilis.————.—...__T_____________ 37

eboreus eboreus_—_._._____________________ 36

Choptank formation, description of_____________________ 5-6, fig. 1

fossils in____________________________________ 5-6

Shattuck's zones in.______..__...________________ 5, fig. 1

chowanensis, Aligena..____________________________ 15,87, pi. 14

Verticordia (Trigonulina)_______________________ 14,51, pi. 10

TJzita—.......__................._____._...__._....___ 12

chuckatuckensis, Donax_________________________ 16,106, pi. 23 

clathrodon, Bahgia. ______________________________ 10 

clavata, Pholas..—.—.—.———......._____________:___ 142

Cleidlopbora crassa...___________________________._ 47 

Clidfophora- ——__._____.________.__._..........._.... 46-50

clintonia, Chlamys (Placopecten)-..„__________________ 37-38,pi. 6

clintonios, Pecten.___.____________________________ 37

Pecten (Chlamys)_.-—————....—..„.—_______.___.__ 37

(Placopecten).-...--——.—....—......._......_...... 6,7,9,11,14,37

CocbJodesma.__-________________________________ 42 

antiquatum___—.„...._..__.....__________________ 42

Codakia cribraria__________________ T ___________j... 78 

coheni, Astarte..————.—.———.———.—.._._________ 9,53, pi. 12 

colomba, Hemicardium___.........._.........______________ 93

columbiana, Carditamera.._________________________ 69, pj. 15

Carditamera arata --___________________________ 15

comparilis, Chlamys (Aequipeeten)_____________________ 37, pi. 7

Chlamys (Plagioctenium)-.—.-..__........______________ 37

Pecten_———„——___._„____________________ 37 

(Chlamys)—.-______________________________ 37 

eboreus_.....___._________________________ 37

compressa, Petricola___——————4——.—___._____.___ 85, pi. 14

Sportella.————________._____-...-_____ 15,85, pi. 14

compsonema, Astarte-.._____________________________ 61

concentrica, Artemis__..„.—..._———......._._____._____ 122

Astarte——........—.——......————................_...__... 59,61

(Ashtarotha)_...__________.__......_... 10,12,14,5S-60, pi. 12

Venus..__..............__...___._____.....___.__... 120»122

Page 

confraga, Spisula.----.—.———.———————————————————————— 6

congesta, Hemimactra———————————————————.—————————— 113 

Mactra ——_....——_—.———_—.—.——1————————-„— 113

Mulinia————..__.____—~——.__- 8,9,10,11,12,16,113-114, pi. 23 

Standella..———.—.————.———————————————.——-. 113

congregata, Chama__——_—.——~—-—.—————————————— 9,11

conradi, Astarte (Ashtarotha) concentrica_______._._„___ 14,60, pi. 12

Corbula (Caryocorbula)—'..................................'.. 16,139-140, pi. 23

Isorardia——....—.—.—————.———.—.—.———————,—„ 67

Macoma__..._—......————————————------———.———.— 99

virginiana-——————————————.-——.——————— 16,99-100, pi. 17

Thraeia—-_-__—________———.———...-———. 14,43, pi. 10

conradinus, Mytilus..———————————————————————— -———— 11

constricta, Amphidesma—————————————.———————,——...... 83

Fabella——————————————————————.—.,— 83

Lepton,(Fabella)——'—...__—._.—____—._.—————„ 83

Sportella——————————————.———————— 15, 83-84, pi. 14

Syndosmya.._..:———————————'.................................. • 83

contractus, Phaeoides (Lucinoma)_________________-.._.— 7,10,11 

Conusadversarins.-—--_———.——_————.—„————————----- 8

diluvianus___—_____——....—_-_._—.._—..——.„ 6,13

marylandicus-_-_^__________....__..-—..—..—.... 7,9,10,13

convexa, Callista...—--——„———————...„..————————————— 124 

Cytherea.--------___.............................^.................... 124

eookei, Macoma._—_____.._.-.-.___---_---------- 16, 100, pi. 17

Cooperella——————————————————-—--——— 119-120

carpenterL————.——-.———..——————.— —— - 15, 119-120, pi. 14

scintilloeformis-._______________________________ 119

cor, Chama__.'__„—„•——.——————————————————————— 67

Coralliophaga._______.____.'.—___..___._.———....—— 66

coralliophaga-..—————.————————————————————————— 66 

microreticulata___........——— — ..„.._———. — ..— 14,66-67, pi. 9

Corbicula..—-------------------_..——.„._-----_.__-.-.___.— 64-65

densata..---------——-———-—.—-—-——-———--——-_-— 15,65, pi. 15

Corbula-.-.—————————.-——.——————————— 139-141

alabamiensis_____________._____.__._—.——:——... 139 

guineensis——————————————————————————————————— 139 

idonea.______———.——„—.————————————————— 6 

raaequalis.__.___...............—.—.......—„.„——————— 7,9,12

sulcata-----.-.——-——-——-———————————— 139

sp____-----_———————————————————————————————— 6

(Caryocorbula) conradL.___——————————.. 16,139-140, pi. 23

conradi retusa.___._____........._._„....—-... 16,140, pi. 23

scutata————____—-__._______.__— 16,140-141, pi. 23 

corbnloidea, Thraeia__._-_,_—....—.„..————————————— 42

corbuloides, Bornia_____..—.'.———-—————.. ——————————— - 82 

coronatum, Busycon__._—__ -—————-———.—————"————— 13 

corpulenta, Mya___________-___—__———-—-——————— 138 

eorticosa, Chama-——.———————————————————————————— 89 

Fseudocbama.___-...„..——————.——————-—— 15, 89, pi. 13 

cortinaria, Chione__^_. _____-_-_———————————— 9,15,127

Chione (Chione)-———.——— — -—— ————,——— 127-128,pi. 19

Dione (Chamelea)---------—-------—————- A————————— 127

Venus_______.___.___.-.—....—-_—————.——————— 127

Costacallista.———————————————————————- 123-124

costata, Crepidulaaculeata.-.--—-———————————————————•— 8,10,11 

Pholas—.........._——————————_____—............. 141

costatum, Cardium__..—————.—————————————————————— 89 

costatus, Pholas- __————————.————.— ——.———,—-— 141

crassa, Cleidiophora—-—....———————1——————————————— 4fr

Crassatella.---------__———————-——————————————-——— 61

CrassatelliteB. ——————————————————————— 61-62

marylandicus_.———————————->——————————————————— 5-6 

meridionalis surryensis_ _———————————————————————— 6,7 

sinuatus___________._._—.——.—————————————— 61 

turgidulus...__—————-———————————————————————— 5 

uodulatus--—-—————————————————— 7,9,10,11,12

cyclopterus____._______———.—-———————————— 6,9 

urbannagnsis__.......——————————————————————— 6

(Crassinella) dupliniana___....—.————————'—————————— 64

lunulatus_______-_——^. ————————————— ——— - 62

crassidens, Mactra—.—-————~ T ————————————————————— 113

Mulinia.. ——————————————————————————— 113

Pandora._____.——..._.————-——-———————-——-———. 46 

(Clidiophora).———......................————............ 46-47, pi. 10

Crassinella-....--———————————————————————— 62-«4

dupliniana-_———_____________________ 16,64, pi. 13 

galvestonensis——___-_——————————————————— 9,10,16,64 

lunulata-------..--_-_-__-_____-_________J- 14,62-68, pi. 19

harrisi---_....._.......______————————————. 14,63, pi. 14

nansemondensis___—.——————————————————————— 16,64, pi. 13 

cravenensis, Gemma_______._—,—.——————————.— 187-138, pi. Jt
172 INDEX

Page 

Grenella— —————— ——-_—_—————— , ——-——--— — ..—— — ——- — — _ — 30

precursor......-.-. — ._ — .................... — --------- __ .... 14, 30, pi. 3

Phaooides (Parvllucina) _ ..-. _ --------- _ _.—.—————————__ 78

crenulatus, Phacoides ______________________ .-. ___ ...... 5,9,11

Orepidulaaculeatacostata..--.. ____________ . ______ . ___ 8,10,11 

fornicata— ...... _ .-._- _ _ ___ ......... _ -.. _ _ --.--... _ .,.. 10

cymbaeformis---- ___ . _ ..-- ___ _ .... _ ------------ _ .... 8,12

plana— . ____ ... ______________ --- ________ - ____ - 10 

cribraria, Chione.— _ . _____ - __________ . _ . _ . __ ... ... — 128

Ghione (Chione)- ---------------- _ ——..——.——_————_ — _ — 128

Codakla ______ . ____________________ .... ____ .... 78

Dione (Chamelea).. . _____________ . ______ - _ - _ -.--.... 128

Lucina— --—- ————-——-_ — ———-— — ——_ ——- — -- — -_——--——...-_ 78

(Lucinisca)-----. --------------------- _ —————— — — ——— — 78

Venus...- _ - _ . ____ . __________________ —— ... ___ ... 128 

cribrarius, Phacoides (Lucinisca) ___________ - __ - __ . 7, 15, 77-78, pi. 13 

crispatus, Pholas-- __ - ___ ... ____ . _ - ____ .......... ____ .. 142

cristella, Chama-. __ -- __ _ .. __ _ ----------------- _ .-- _ _ .... 89

Oroatan sand, exposure of ________________ ... ____ .-. __ .. 13 

Crucibulum grande ____ ... __________________ .. ___ . ___ 9 

---— ———————— - — — -———-——— — -—— 74-76

microimbricata.. _ . ___ ------ ______ .... ___ ___ . _ 15, 75-76, pi. 13

speciosa---. _ . __ - ______ - ____ . ___ .. _ . ______ ... 15t 75,pl. 13 

Cultelluscariboeus..- _ .... _ . __ . _ .. ______ ..... ____ _._-__ 107,108

Cumingia medialis ______ ___ ..-..._ ___ _ ------------ _ ... _ .._-.... 12

Cunearca.-- ____________ . ___ . __________ - _ -....__... 26

cuneiformis, Martesia—. _ - __________ - ______ ... _ .. 16, 143, pi. 23 

Pholas— - — — -—-——- ——— ——-'—— —— ——— — — ——— — 143

cyclopterus, Crassatellites undulatus. _____ _ ____ __ ______ ...... 6,9

cymbaeformis, Crepidula fornicata __ __ _ ._ _ ...- _ _ _ ___..._..... _ 8, 12

Oypricardia arata.-— ... _ — .... ___ .. _ -... ________ ... _ ... __ . 68

Cyprina tridacnoides _ . __________ - _ - ____ ____ _._-._— — 132 

Cyrena densata _ ------ _____ . __ . _ --.__-. _ ....... _ __ ......... 65

Cytherca sayana. — __ . __ . _ ...- —— _ .. __ . ______ ______ 124

Cytherea convexa ________________________________ . 124

obovata— — —— — — — — ——— ———————————— ——— 120

pandata.. _____ . __ . __ . __ . _____ ________________ 123 

reposta.. ______________________________________ 123 

sayana— ------ __ - _ .. __ . _ ~ _ — _________ ... ______ 124

texasiana -.--.- _ . — ... __ -..-- — ........... _ _ .-----.-.-.. __ — — 124

dalU,Chione--. — ———.....„.......... —............................. 129

Chione (Chamelea)—................————.——. 7,13,15,129-130, pi. 19

Pandora (Kennerjia)....—..--..-....—....—-....-......-... 14, 45-46, pi. 10

DaUocardia——-----—--—--—-.—---——————-.—.———— 92

decemcostata, Qlans (Pleuromeris) tridentata__..__..__.. _ 70, 71, pi. 13 

Pleuromeris. — ____-__.___...__.______....____._ 70,71

tridentata-------___________...-_-__-_-_______ 15

Venericardia (Pleuromeris) tridentata-.---.-_...._.___._.___ 71

decemnaria, Chlamys.___._..__.._.-... — -___..____... 31-32, pi. 5 

decemnarius, Chlamys (Chlamys)-_.....___.___.......__-_.... 31

Pecten—_____-_-______._-_..__-____-__...__ 31 

(Chlamys).-—...-.--..-- — ---.-.--- — --..-----..—„....--.... 9,10,31

decipiens, Pododesmus.__________.___...._.___..._._.. 40

dech'vis, Tellina..-----------_-_— - —— - — ——— ——— _ — - — — _ 12,94,95

Tellina (Angulus)-_——— — ————- ———————— ——_ ————_ 95

(Moerella)———————-'-—————————.-—.- 94-95

Thracia——....-—. — .— — . — ..— — -..—.—.. ——..........., 43

decussatus, Mytilus.---:_________... — ._______...______. 30 

deformis, Venus..-___.....____.--.-----..---..---....___.. 132

deltoidea, Abra aequalis.————————————— — ——— 16,104-105, pi. 17

Astarte (Ashtarotha) undulata. ——...-.-....-.-....... 6, 7, 9,11, 14, 59, pi. 12

dehimbis, Spisula___...._____-----------_......___...__. 8,12

densata, Corbicula...____..._-_________..._______ 15,65, pi. 15

Cyrena-______________.__.__.____.___...__ 65

Dentalium attenuatum.. —-__..._..___-__._._______.. 7,11

carolinense...__..________1___- —...__._.... — -.___. 13

diaphana, Nucula__-____________-_._-----__•__.. 20-21, pi. 1

diffonnis, Venus...--.....-...----..... ——--..........-....;—............ 132

Diluvarca.—_—- — — ——_—- — -——-—————.—— ———. 23

diluvianus, Conus-_.___________..___-„.._-___-----_..._ 6,13

Dione obovata_...-__.--_-_....^...............__--------------- 120

reposta------------------.---------------------.-.--------------__---,_--- 123

sayana___-__.-__-----------------------__------__.__ — 124

(Chamelea) cortinaria- —_-.._------__---------------------_-_ 127

cribraria-..____..__.____.._-___.__„_____ 128 

Dtplodonta—. —— -..-- — -..-..-.--. — .—-..---.-----.-.--- — .-„. 79-81

caloosaensis_._...__.__....._._._____.__-___.. 80, pi. 14

leana..--.-----------_---..----_.-.---.—-..-..„...-.--..--..-.-.... 15,80

eoleana..--_-_--------__.___.__ — — _..._-__ 80, pi. 14

semiaspora_.___.....___.._.___...._______- 81

sorer—_-_..--.------_____-....-„-..... — ___--.-_-.----__- 81

Page 

Diplodonta—Continued.

subvexa____-___...__——_—..—-———————————- 5 

yorkensis_____________________-__-...—.———.—... 119 

(Phlyetiderma) soror...—.——.——.....—..-...—..—.—.... 15,81,pi. 14

dislocatus, Pecten-.__________._____—..———.—.—————— 31

Pecten irradians_______________________________ 31

dispalatus, Pecten...____...___._.._—..—————.————;— 31

djsparilis, Ostrea--———————————————————.—— 6,7,9,10,11

Divarieella quadrisuleata__..____——_.——.————————————, 7 

donacia, Mactra__-...-.-._..-.-—--—_— — ——— ——— ..«.—— 115

donacina, Tellina___----------_.___:..._--------——---------—— M

Donax_______.______.____._..__„_————.——„———— 105 

aequilibrata______________________.__.__..:.., 106, pi. 17 

ehuckatuckensis—--——-—__._..___.....__-_—..—.. 16,108, pi. 23

emmonsi_____________________...—..——,,.—_—- I05,pl.23 

preaequilibrata--------__——,_".——„—— —__..... 16,105-106, pi. 23

fossor—........... - — - — —— ——————,—-—...... 16,106-107, PL 23

protracta____..__._________..__.__.--.————————— 106 

rugosa....__-----_-..-____.._—..——-———————— — -—— ,105

variabilis.-- —-.—-- — -—.- — - — ————-———- ———.-. 106

dosin, Chama.._____________________.....—_..._——— 120

Dosinia—......................_........_._......._....._---------- 120

acetabulum-_____________________,-..--„. —.———— 120 

africana__.___.._____________._.._.........— 120

..............................................................^ 122

obovata....—....—.—.——.—.—.—.————.—..—-...=——-,. 120 

sp.-——-————.--—--.---.---.-.--------—----—.....—.—-— 6

(Dosinidia)acetabulum_. —„ — -——-—-..———— 7,10,15,120rl22,pl.ll 

elegans-.............._.....____._...._—.—....„ 15,122, pi. 11

Dosinidia-—- — —————.—._—.....__---------------_-------- 120

"Drillia" myrmecoon-________________________.___.- » 8^ 

lunata.-..------------------___...._......._—..———....:... 7,10

pyrenoides____.-..___-_________________-._-_.. 10 

dubia, Psammotea_______________________—__.-_——. 83 

ducatellii, Modiolus..————————..—.—.—- ————-•—-— 12

duplicatus, Polynices_.____.__...'.—_____...——.——.———— a 9

dupliniana, Crassatellites (Crassinella). ____________.__-_——. 64

Crassinella----.--.-.-__-_..._- —— ———....__........ 15,64, pi. 13

TeTlina (Angulus)-—_.—_———_——.—-———————————— 96

(Moerella)——————————————————.-- ——.— 96-97

duplinensis, Glycymeris___________..____...—..——. 14,27,pis.2,5

Spisula (Hemimactra).____________________.______. 112

' (Mactromeris)—.———,————————————— - 112-113,pL22

Duplinmarl_...__________________________-_------- 13

dysera, Venus.-__,.__________________...__------------ 127

E

eborea, Chlamys (Aequipeeten)________________...—__. 90-37,pi. 7 

eboreus, Chlamys (Plagioctenium)_____.__..-.—...-———.,——-— 36

Oliva——— — — .——..___--.-___-.____.-____---.-_.-- 13

Pecten.,-..- —— ......................___...———.———— 8,9-11,12.36

(Chlamys).. —————————..—————,——--—— — - 36

(Plagiwtenium)...—_—_,—--—---——--—. ———- — — -— 14,36 

eburnifemm, Cardium_________________._-„.——.- — —.. 91 

Ecphora tricostata___.__________________.__../........ 5

edgecombensis, Cblamys (Lyropecten) jeffevsonia—....._-.....--.... —— _. 33

Pecten jeffersonius——_________.__-------——.————— 8,9,10,12

edule, Cardium.----.--______---._-_-...—------- — -- — ....— 89

edulis, Ostrea_______..______________._ — _...„.——— 41 

egena, Tellina-..————— ———————————————— 16, 98, pi. 17

Tellina (Peronidia).—................'.————.——————————,- 68

egmontianum, Cardium______..._..._ — ——————————— -— 91 

ele?ans, Artemis..------_-..-——.—— —. — - ———_— ———— — — - 122

Dosinia...—————_.—___.....—.——. — —— -.—....•.„ 122

Dosfnia (Dosinidia)-———————— ———————-—- 15, 122, pi. 11

elongata, Erycina carolinensis——__————— —— ------ ——— — 15, 82, pi.'14

emmonsi, Donax.__.....—A——.——————————————————- — 105, pi. 23

Macrocallista (CostacalUsta) —————— —— ———— 15,123-124, pi. 19

emmonsii, Cardium (Trachyeardium).-__-_.——- —— -———————>.- 92

Trachycardium__.____-------------------- —— ——— — — ———— 92

Verticordia—— __.—__—.——----- — — ———————————————— 50

(Trigonulina) ——...............———. ———————— 14, 50-51, pi. 10

eoleana, Diplodonta leana_.___.... ——.. — -————————-——— 80, pi. 14

Eontiacarolinensis------------- — — —— — — ——— - — — — — - ——— --- 12 ,

trigintinaria.-_ —._—. ——————— ————————— - —— -———— 9 

Eriphylagalvestonensis—----————————————————————,~———— 64 

ernestsmithi, Chlamys (Lyropecten)———————————————-——\34~S5, pi. 6

Peeten—---------------—........—.....——.—-———————— 34

(Chlamys)-.——-—————————————————— — 34

(Nodipecten).-—-----__.............-..—.—————— — .—— 14

Ervilia.--------------_...—__.............—----------——._.——.. 116

lata——— — ————————————————— W, 115-11*, tf. 2*

radiata——-—————-———————.—.———- 16, lie, pi: 23
INDEX 173

Page 

Erycina.----—".________________________________ 81

earolinensis__________^_________________ 15,81-82, pi. 14 

elongata.—...-.———————————————___. 15, 82, pi. 14

pellueida-.____..____________________________ 81 

erycina, Venus...._.-.-._.______.....__.._....._._.._ 123 

Erycinella.................................................................... 73-74

ovalis.......................................................... 15, 73-74, pi. 14

estrellanus, Lyropecten._____________________________ 32 

Euloxa..__.____________.__.-'................................. 65

latisulcata..--.---.--......................................... 6, 65-66, pi. 15

europaeum, Cardium___________________________.__ 93 

Euvola...___..........................__.........._......._......... 30

exaltata^Astarte.........—..-.....--....--....--.--......... 6, 7, 9, 14, 52, pi. 12

exilis, Fusinus—,—__.___..._.___..________________ 10

Fabella constricta...___________________________._ 83 

Fasciolaria rhomboidea.___...______________.______... 8 

fllosum, Busyeon maximum___________________________ .13 

Fissuridea_-.„_________________..._______________ 9,11

nearnassula..__._______.._______._____________ 7

redimicula._._________.____________________ 7,9,10,11 

fistula, Teredo............__———————.——.———————..———.. 143

floridana, Pandora (Clidiophora)....—___.__._____________ 49

floridanum, Cardium...___._________________.______ 92 

fluminalis, Tellina________________________________ 64 

fornicata, Crepidula...——.......——_.—.„..___._________ 10

Petricola____.__.—__..._____________________ 117 

fossor, Donax?________________________.. _____ 16,106-107, pi. 23 

fragilis, Mactra....---..-.---.---...-.-----.-.----.-.--..._................ 109

Mactra (Mactrotoma).______.__________________ 109, pi. 18 

fraterna, Bucardia————.. —.—.———.—_„___—______.._. 67

Isocardia—-——-—-——.—————————————— 5, 7,15, 67, pi. 11

Fulgur eanalieulatum canaliferum___________. ___________ 8 

Fusinus exilis_——————————.——————_.___.___—__._ 10

parilis_._-.—..__--—......--__...___...___...._........ 13

propeparilis.——————————————————- — --..--.._ —— _-... 7,9,13

Q

gallina, Venus,_______.-..__.______———.__.._______ 129 

galvestonensis, Crassatellites (Crassinella)...____._-....____.. 63

Crassinella^.-—~~~-~~~~~~~--~~—---------------------- 9,10,15,64

Eriphyla—.————-—-—-_.-......-.-.-.---.......-.__.......... 64

Gemma...____._____--__._._____.._.________ 135-138 

eravenensisl——— ——— ———---—.—.—--..-„.„....... 137-138, pi. 19

magna._——._—— ——————————_—— —— —...—— 9,135-136

tosulcata.--—.—- — ———————— ————— 15, 137, pi. 19

majorlna———— ——————————————— 15, 136-137, pi. 19

virginiana.__....——._._-—..————_...._.. 16,136, pi. 19

verdevma———————————————————————— 138, pi. 19

gemma, Venus_——————————————————— — ————————..—. 135

Geologic ranges of certain species—.—.—.———.....—.—..„ 13,14-16 (table 2)

gibba, Ostrea__-———.——————————.:———————————.._ 31

gibberosa, Sportella.._-...-...--....-.._.—...—........_. 15, 84-85, pi. 14

gibbus, Pecten (Chlamys)..———....--.....--...-.....—................ 31

Peeten (Plagioctenium).————.-..„————.———.——_„_ 14, 31, pi. 5 

Solecurtus (Tagelus).-.....—„ — — ...„.„............—.............. 107

Solen———....................——..————.————.———..— 107

Tagelus—————..—————————....................... 16,107-108, pi. 22

gigantea, Mactra.___——...—————————......———————........ 110

Venus_____________.___.....________________ 122

Qlans..——————...—.———————.—........—..........——.. — .. 69-73

(Pleuromeris) tridentata_——..—.————...--.___„__.__._ 70-71 

tridentata decemcostata._.___.._______.___.... 70,71, pi. 13

(Pteromeris) perplana.______________..._________ 72, pi. 13

perplana abbreviata_________—____________ 72-73, pi. 13

glenni, Isocardia fraterna_______________________:.. 15, 68, pi. 16

Glossus rusticus..___.___—__———...__..___...__._____ 67

Glycymeris.-.----.------.--..-------...-------.---------.-...—............. 26-28

americana...—.—... —— .-..—...---.-..--...--—_r——.. 10,13, 27-28, pi. 1 

Area_________-_______-_.-____-_-___-___-_ 26 

duplinensis_______________________ _____ 14, 27, pis. 2,5 

laevis——————————————————————. 14, 26-27, pi. 1

orbicularis_.___—___.._——_——„.—.—.——_—__-... 26

subovata_________________________._______ 6,7,10,12

plagia......__..__—————————————--.-———.—_— 7,9

tuomeyi________—__—__——_____.__-___... 9,11 

tumulus-.....--....-.-.———————————.—————— 6,13,14,27, pi. 1

goldfussli, Panope___———.———————.——..——.-——————..—— 12 

gouldiana, Pandora__________...__.__________._____ 49 

grande, Crueibulum_______________________________ 9 

jgranifera, Hyanassa______.___—__—__—__——_—__—— 8 

graniferum, Cardium-._.--...-.--.-_--..--..----__...___._ 93

401033—43———15

Page 

Granoarea—__.-.-.__________f..................................... 22

granulata, Veneribardia—.......................^................... 6,7,9,10,11,12

griftonensis, Astarte (Ashtarotha)______________________ 14,57, pi. 12 

grinnelli, Petricola (Claudiconcha)._____________--...-..____ 117

Petricola (Rupellaria)______....___,_______-__ 15,117,pi. 15 

grus, Chione (Chione)..————— ———————————— — 128-129,pi. 19

Chione (Timoefea) — .„.. — ...............i.-.......................... 15,128

Tapes. ...„..-.-__-...........-..-..---._.-..—..—..--..._........ 128

guineensis, Corbula—„_.___.__.—__-__..__——-.-...___ 139

Solen..................—— ...—..... ——.............................. 107

guttata, Callocardia.... —--————-———.——.—_——..——.—..—— 124

hamatus, Brachydontes____________________________ 29 

Mytilus__.__.....__................._..___._.......___ 29

Mytilus (Hormomya).-..__..............„•.....—.........._......... 29

harrisi, Crassinella lunulata____.__....._:________'..... 14,63,pi. 14

harrisii, Petricola (Rupellaria)._______._________________ 119

Hemicardium columba__..__..__.___..__.___._.._____ 93

Hemimactra________-______________-___________ 110

congesta-..—".——-...——.—.. —. — - — ...-—...-...—......... 113

heros, Polynices....___._.-.---.----.--._._...-_..*.................. 10

hertfordensis, Astarte...__.....___.__.______.__ 11,14,53-54, pi. 12

hians, Area.___——._____________._____.___.____ 22 

holbrookii, Pecten....___..._..__._..._____....___ 36

Horsehead Cliffs, Va., section at_______._____________'....... 5

humanum, Cardium-_________.____________.._______ 67 

humile, Calliostoma.-----.-_--—--_-_---.-_------------_______ 13

hyperborea, Yoldia.._.______.__-___-__ —.__._._______ 21

idonea, Area———-- —————. ————————..-- ———————————— - — -. 6,7,13

Corbula..._.___.--_____.____--______..______ 6

Hyanassa schizopyga.—._____..._..___-___-.__.___.___ 8

granifera.— ____..---__----...—._-------.----.-.-__—__ 8

sexdentata.......—__—__—...-.-- —————.-—__..___ 12

improcera, Area..________________.____--.______._ 8,12 

inaequalis, Corbula.______.____-__._______________ 7,9,12 

inaequivalvis, Periploma....___...._.......—_——.__. — ___._ 42

Tellina.....----......----__----------_.....--_.-_-.-„.._..... 44

incile, Area (NoStia)—.........._—„...—-....- — -————.„_.. 9,10,13

incongrua, Area.._—.....---...——.———.... ———— --...————__ 26

inflata, Venus plena"....____.- — _ — — _.--..--..-. — — ..-.-.„-.._. 134

Venus (Mercenaria) plena..____._.........__...__.. 15,134, pi. 21

ingens, Cardium_....--- —..... —....---.-..—.———.. ——— ———... 90

insulcata, Gemma magna..—__—.... —...———————.——...- 15,137,pi. 19

Introduction_..__-_-——.-,——..—.--..——----------- — ------_- 1

Ischadium_.. —— ———————————— —— —————.... —— _. ——. —— —._ 29

Isocardia--.——......—.——.——————.——————'_. —————— 11,67

Cardium.--...-.——.————....—————..-—-——————- 91

(Trachycardium)...-----„---—„.—.-.—........................ 15,91

Carolina__.._. —.. —. ——— — ————- — --—-. —— —..——— 67

conradi..——...——.———— ———.--... —— —.-. —. ——— . ——— 67 

fraterna—— — ,————————- — — —————— 5,7,15, 67, pi. 11

Carolina. — .——————— — ——-————— 9,11,15,67-68, pis. 11, &

glenni...-..... — — ..————————————— — — — 15,68, pi. 16

rustica.———...——.——————————————————————————— 67 

isocardia, Trachycardium...———————.——————————————— 91-92.pl. 15

jeffersonia, Chlamys (Lyropecten),___..__._...—_———.—. 32-34, pl.4 

jeffersonius, Pecten-.———...——.———.—————......—— 6,7,9,11,12,32

Pecten jeffersonius...——-. ———— —— ———— —————— --————.—— 8

(Lyropecten)---——————————————————————————————— 33 

johnsoni, Nassa___—-- ———.-- —— —— -------- —— ————— - — —.—— 8

K

Kellia triangula. 

Kennerlia-------

.——————————————————————————— 82

.————— ———————— — — —— — ——— —————— 45

kiawahensis, Lucina_.-. ————————————— ———— -- ———— —— ———— 81 

Kuphus..———.....——........—.....——————————...—.— 143-144

calamus—————'j—————__....„.————— 6,9,10,16,143-144, pi. 23

Laevicardium.-.______.___-__—————————————.————— 93-94 

sublineatum.—.———.—————.......——....————————— 94, pi. 15

laevis, Glycymeris.....——————L................................. 14, 26-27, pi. 1

Nucula.-____-_——__—.----.—————..——.-.-—-————— 21

Pectunculus.-_...__——...—..-. ————————— ——————— ——— 26 

Yoldia...——————————————————— — -—- 10,14,21, pi. 1

lapicida, Venus __———————.————————————————————————— 116

laqueata, Ptychosalpinx..————————————————————————,-,—-. JO
174 INDEX

Page 

laqueatum, Cardium...———————————————————————————,— 90

Cardium (Cerastoderma).._——————.———.————....—_._. 90

Cerastoderma—————————————————....———.— 90, pi. 16

lata, Eryilia——.—.——.......-....—.———............... 16,116-116, pi. 23

Semele--.___.._——_ ——...——.—————.—.._...__._ 102

lateralis, Mactra.-————————————————————————————...—— 113

(Mulinia)------- ————.........—.......—..........:...... 113

latisulcata, Euloxa.— .___..__—__—————___.____ 6,65-66, pi. 15

Venus...-.—— —————.——————. ————————.————-----— 65 

lazurus, Chama.—-.-_-----_——-.-——..-——-----—___.____ 88 

leana, Anatina_------ —— --------------------------------------_-.-__-- 42

Diplodonta...____._____-_____________._____ 15,80 

entiformis, Pectunculus..-—_——-..——--———__—'.________ 27 

Lepton (Fabella) constricta-..___-.__.-..___-_____________ 83 

lienosa, Anadara-....__——__——-_.—------------- —._____ 23-24,pi. 2

Area-..-._——-———--. ——.-———-——-----——___.____ 24

(Anadara)-- 

(Scapharca)..

Scapharca.. -.— 

limatula, Marginella.

Nucula..........

"limatula," Yoldia.. 

lineata, Astrangia....

lineolata, Astarte__ 

Xiirosoma sulcosa....

lithophaga, Venus... 

Lucina cribraria— —

kiawahensis__-

multilineata.....

soror.. --..--.----._..._-..-_--.._— ——— — —_...._.._.

tenuisculpta__-.-_._--.-.-_-.-.._-____-.__._..__._.

(Lucinisca) cribraria___________....I______________.

Lucinisca_____.________.______._____._________. 

lucinoides, Psammocola.. —— — — --—_-----------.--...-.-----.__....

lunata, "Drillia".---.-..____-...___._.___-...._....__.

lunulata, Astarte_.____.._--....„.-......„._._.________.

lunulatus, Crassatellites (Crassinella).._...........____...______.

lunulata, Crassinella_.____.----......„....._..._.....__ 14,62-63,

lupina, Venus..__.._.__....__..........._..... — ...______.

lusoria, Tellina.._.....__............................__.....___......

(Peronaederma).._.........._..._..___.___.______.

Lyropecten.._.___............................._......................

estrellanus_.__.__._......_....___...._..__._____.

23 

14 

23

8,12

21

21

9

61

10,11 

116 

78 

81 

78 

81 

78 

78

77-78 

80

7,10 

62 

62

pi. 19 

79

98

99

32-34 

32

M

macilenta, Tellina (Angulus).__---..__.--.__.______................__. 97

Tellina (Moerella)--------------.---..--..-.--..----..---.---.--...... 97, pi. 17

Macoma._—-----------___...._........._.-...____------.____.__ 98-100

carolinensis.----.-----...-._--..----.--..-............__-_......_... 100

conradi.---------_........................................_____ _ ___ 99

cookei..--.-.—.........- — .....-—.......................... 16,100, pi. 17

tenera...---..--..-.--------..---------...----..............-............. 98

virginiana...—-—— — __-_- — ___--_._-_.___._._.-_________ 16,98-99, pi. 17

conradi....-.—................. —....................... 16,99-100, pi. 17

Macrocallista.—__-.____.__._...__.....______._.___ 122-124

reposta.......——_ — -—___ — _—_ — ___—_ — _____._——_ 15,123, pi. 19

(Costacallista) emmonsi....................___..._._.. 15,123-124, pi. 19

Mactra...-__.._.....__...--._._.....__._.__.____... 109

congesta._............................................_._....___ 113

crassidens.--__.__...-._......____.._.....______,___ 113

donacia..__.......__.___._._........_..__..._...___ 115

fragDis.__'.„......___...___._..__.._.........______ 109

gigantea.................................................................. 110

lateralis......____-.-__.._-.._____-------_----............__... 113

similis-..........._i..........__-_______.__.______.... Ill

solida...._--.--__-.-_.....---......--.-._........._........__. 110

solidissima.---.-..---.-.--..--.----..-...--........................._.. 110

stultorum.-_._....___......._____.__.____.____._ 109

tenuis..__.____...._.__.._________._________ 103

triquetra..___.__.._.___......_____._.._......___. 113

(Mactrotoma) fragilis____..___....._.............._______'109, pi. 18

fragilis precursor..............___...___-„......_ 16,109-110, pi. 18

(Mulinia) lateralis...____________________........_..---.--.-......._. 113

Mactromeris._.-.-_.__._____._-.-.....--......_.._............_... 112

Mactrotoma......_______.__..,.-..__.....__.___._.__...... 109

maddelysensis, Thracia.-.-..__.._.__........_......_____ 14, 44, pi. 10

madisonia, Chlamys (Lyropecten)____________..._......._ 32, pis. 4, 9

madisonins, Pecten_........_....__-.-..----j-................__.... 32

Pecten (Chlamys)....__.____._______......._________ 32

(Lyropecten)......-................................................ 5,14,32

magellanicus, Pecten._._____.____________..._______ 37 

magna, Gemma.-__________._.._________________ 9,135-136 

magnoliana, Anadara...____.._..__--..-___________ 25, pi. 3

Mangilia, aff. M_..........................................._........... 12

Mulinia congesta.....________________...________. 114-115

Spisula (Hemimactra?)........ ———.————....................... 114

Pag* 

majorina, Gemma magna—-_——————--—.——......—— 15,136-137, pi. 1*

Myaalto-..—-.———.—-.—— ———.———..—. 16, 86-87, pi. 14

Pandbift(Clidiophora) crassidens...-.----..---.--..-.—........... 47-48, pi. 10

Mangilia ak. magnoliana.----...-------.-—......---.-.-.-------.-.——.... 12

marginata^Plicatula.—„........—..................—.4—.. 9,10,14, 40, pi. 11

MarginenlTbella—————.————-————-—-—————_ 8,12

limatuia.———..———————--—-———-———-—- 8,12

Martesia--.——— —————.—————————————————.—— 142-143

cuneiformis. ——————————————-—-——— 16,143, pi. 23

Maryland, Miocene stratigraphy of, summary of.——.————— -————— 1-2, 18 

marylandjca, Chlamys (Placopecten)__——..—.—————————— 38, pis. 5, 6

Septastrea._„.._.————————————————-——————-—— 9 

marylandieus, Conus____.__—..—. ——————————.————— 7,9,10,13

Crassatellites- —..-——————.—————.—————.-. 5-6

, Pecten-,-...—-——.—-———————————————- 38

(Chlamys).--....-.--.—-—————————--------—————... 38

(Placopecten?)................................——...————.. 8,14,38

maxillatum, Pedalion..,-——_———.————————————————_—— 8,6,7,13 

maxima, Ostrea_....... —.. ———.. —— -- ——— ———— ————————— 30

media, Trfeoniocardia (Americardia)...—.—_—————....————.—— 93

medialis, Cumingia.-_—.—————————————————————————— 12 

medium, Cardium..___.._—.....———————————————————— 93

Cardium (Fragum)..—.....———..—.-.------.-----_—....——.— 93

meherrinensis, Astarte hertfordensis—.——.—————————————— 14,54, pi. 12 

Mercenaria.— ———————— ———--..-— ——.—....—........ 130-135

carolinensis_..__..-_————————————————————————— 132

notata—.. ——— ..........—.————...—................. I——... 130

percrassa..._......——..————————————————:———————— 132

tridacnoides-_________—_———————————————————— 132 

mercenaria, Mya..._._-_-------- ——— -- —— ——— —— — ——— —— 138

Meretrix sayana_____~__———————————————-———————— 124 

Mesodesma..___.._----_... —— — ——— ——— ————————— — 115

spatha_______________--.______________ 16,115, pi. 18 

mieroimbricata, Ctena.------.------.—--------------------------- 15, 76-76, pi. 13

microreticulata, Coralliophaga?.----------------------------------- 14, 66-67, pi. 9

middlesexensis, Pectensantamaria—.--.-.--..--- — ------ —. ——.-..—— 6,7

mUleri, Anachis........——————————————————— 12

mitchelli, Calliostoma... — ...—.......——...——.—.. — ..——.——... 9

Mitramorpha, mltrodita......... —————— —.. —.— —————— --.—— 8

mitrodita, Mitramorpha_--._.-—.„.... — .——...—————————.——— 8

modicella, Spisula (Hemimactra)-———... — —— .'...—- — ..—.- 16, 111,pi.23 

Modiola carolinensis.__.....—-———. —. ————. ————————— — 29

sulcata--———————.—————————————————————————— 29 

Modiolus ducatellii—................————..—...———.,——— — . 12

pulchellus.---------------- — — — -.- —————— -- ———— ---- ——— -- 9

Moerella——————.————————————————-——— 94-98

Monia..—________ —. ————————— -——————————————— 41 

mortoni, Amusium_____.._——... —————————————— _————— 39, pi. 8

Pecten—---------------------------------------------——------------ 39

(Amusium)....-.————— ——— ———————————————. 14,39

Mulinia— — — ——— —————————————— ———————— 113-115

.—————— —— —————————. 8,9,10,11,12,16,113-114, pi. 23

ma,gnoliana__.----._ — -•.....-- — — — -___ —— --------- ——. 114-115

crassidens-_—„ ——._-_ —... —. — - ————————— -———————— 113

triquetra--__.__—_ ———————.———————————————— 113

multilineata, Lucina.._____......————————J——————————.— 78

Parviludna—————. — — — .— ————— ——————————-- 79

multilineatus, Phacoides (Parvuucina)..——————————— 15,78-79,pi. 13

multistria|M8, Phacoides—.—-————-———————————— 12

Phacoides (Cardiolucina) trisulcatus.___.-.._———.———— 76-77.pl. 13

(Cavilucina) trisulcatus-_———————————————————————— 9,15

murfreesborognsis, Phacoides eontractus—. ——— —.——————————— 11

muricatum, Cardium__------———— — — ———— ——— — — — ———— 92

Cardium (Traehycardium)-. ——— ————————— ——————- 92

Trachycardium.——————————————— ———————— 92-93, pi. 15

mutabilis, Seaphella (Aurinia)..— —— ———— ————————.——.——— 9,12

mutica, Olivella———————————————————————-————————— W 

Mya————————————————————————————— 138-139

acuta.-------—... ————— - — ——— - — — ———-——— — ——— -- 138

arenaria... — ——————————————————————— 138-139, pi. 22

corpulenta._—....—. —. ————... ————— - — —— -——————— 138

mercenaria-----_._ —... -,-————————— -———- — —————— 138

truncata...--.... — „ — —— — —.... — — — ———..-..-.- ————.. 138

Drillia". —— ---———— — -——— —— -—-- ————— 8

——————————— ————————————————— 85-87

myrmecoon,

Mysella..--.

anomala..--------————————————————--———————— 86

bladenensis—_...——————__———__......—————. 15,86, pi. 14

majorina—————— — —————————————— 15,86-87, pi 14

stantonl.———————————————————————— 86, pi. 14

v61aini—-------_-_...———.——————__ — ....———.— 16,86, pi. 14

Mytilus conradinus...—.——————————————.————————————— 11

deeussatus-——————————.——-——————————————————— 30

hamatus__—.———.—————————————————————————— 29

(Horinomya) hamatus.....————————————————————————— 29

recurvus-.-—.———.....———.„..„,;.„,„———.—.——... 14
INDEX 175

N Page 

nansemondensis, Crassinella____..:_........________ 15,64, pi. 13

Nassa cf. johnsoni. _______..._____________._________ 8

nassula, Flssuridea, near V,.......:_______________________ 7

naviculoides, Pandora (Kennerlia)..._________.....__._ 14,46, pi. 10

nexilis, Semele____________._______i__.._.._____ 102 

nlmbosa, Venus..___________________________.____ 122 

nitidula, Oliva—....-__..-.-.._...._................_............._ 12

Olivella.—.—.........—.....—.......—............................. 8,12

noae, Area,______________________..___.....__ 22

Nodipecten....___.______________________________ '34

nodosa, Ostrea.__________________________________ 34 

Nomini Cliffs, Va., sections at..______________________ 5

norvegieum, Cardium.__________________...________._ 93 

North Carolina, localities in.____________________.___ 17,18,19 

notata, Mercenaria.._______....________.____________ 130

Venus.———— —— ————__._..............-.---....----...- 130

(Mercenaria) mercenaria.—___________________ 15,130, pi. 21 

nucea, Venus plena....__.___.____________________.... 134

Venus (Mercenaria) plena_________.____________ 134-135, pi. 21

nucleus, Area.___________________________________ 19

Nueula.__.______________________.______.___.._ 19-21

diaphana...---.----------._-.-.-..----.........--..-.--.----..--. 20-21,pi. 1

laevis_______._______________.______._____ 21 

limatula._._____________._____.____________ 21 

obliqua__.________...__________________..__.. 19 

proxima.-.--.--__.....-.-.-.--.....-.-....----.-.--.....-.-. 12,14,19-20, pi. 1

Nuculana acuta..______...._____.______________.__ 9,12

nuculiformLs, Abra..._..__...--.-._.._______-,.-._____.__ 104

nuculoidea, Seinele. __._______________.._____.___.__ 102

nueuloides, Amphidesma___.__ __. ___________________ 102

Abra......—1....—.————..——.-—..————.—....— 102

Semele-..-.------.-.-----.-..---.----.-..--.----...-..-.--..-...--...-. 16,102

(Semelina)--—————- — ———————— —— .—— — . 102-103, pi. 17

Semelina...__.____.________________________ 102 

nuperum, Solarium—...._—....——..——____.__.________.. 11

0

obliqua, Nucula.______________________.____ ____ 19

obovata, Cytherea_.__..__—_____________________ 120

Dione.___________________________._________ 120

Dosinia.—..———.....——.—...—...—.—.—............—...... 120

obruta, Astarte___..___._-___________________._ 5

Astarte aft. A___.__—_...__.._____.__________.. 6

Oedalia subdiaphana.——————.——._—__..__-.___.__.__... 119

Oliva eboreus________.___..______._____________.. 13

nitidula.-.—--——.- ——--.-———.— —— — ——————— 12

sayana...—..————————————..—..—_—_..__.._— 10 

Olivellamutica.——————.—.——-———.—...————.—. 12

nitidula--.--- —— — — ———--.- — -.. — -.——— — --..——— 8,12

ornata, Trigonulina......._—...—__..____._______.._..... 50

opercularis, Ostrea_—.... ——.—-.----.-.-.-.._.._.--.._.._.... 35

orbicularis, Qlycymeris..._ — _.__...___._____._.____..... 26

Ostrea-..-----—--------_..............._......— ...... .............. 11,41

disparilis-.——.—————————— — — —— -- — ——— — —— 6,7,9,10,11

edulis.......—————.———.——— ——— .——.—— -- —— ——— 41

gibba———— — — — — ————— — — ———..————————... 31

maxima___.._.---.-.----..--._ — — — —— — — — ——— — — — 30

nodosa-_____„-..„-.__——_..__.__..._____...___ 34 

opercularis-...._____._____._..._.____.__________ 35

pleuronectes—— — ---------.- — — _..___------_---._.-.. — - — 39

sculpturata.- — _.___._____._.____________.... 8,9,10,12

waeeamawensis—.___........__.______.____.__.. 14,41, pi. 3

ovalis, Abra—_________.______...__________.--—'....- 101

Erycinella. —- ———— ———————— ———— — — ——- 15,73-74, pi. 14

ovata, Pleiorytis—————.———..—-—————- ————-- — 118

Venus..-..-..-.-—......................___.——.———_.... 128

pandata, Cytherea. ___ . ___ . _ . __ _ . ___________ _________ 123 

Pandora. ________ __________________________ ___ 44-45

arenosa—

bilirata——

carolinensis

crassidens..

gouldiana.

—— .. —— _ .. . __________ — — _____ 45 

————————— -————— ——— -.— . —— -.——. 45

_ ___ .. ___ ___________________ 45 

. _________________ ____________ 46 

. _____________ _______ 49 

triltaeata. — — -————-— ——.——-— —— — — — ——— 48,49

(Clidiophora) crassidens-... —— — ........— ....... — .——...„ 46-47, pi. 10

crassidens majorina.. _ _____________________ 47-48, pi. 10 

floridana.— __________________________ . ___ .. 49 

prodromus ___ .-... __ _______ ___ ......... _ ........ 48, pi. 11

trilineata.— ... ——— ... ... ... ...... ..... ..... .... ..... ... ... .. 48-49, pi. 11

tuomeyi. .----. ----------- _ —-..„...„—....—.„ __ 48-49, pis. 10. 11

(Kennerlia) arenosa __________________________ 14,45, pi. 10 

bicarinata.. ____________________________ .. __ 45 

dalli————————— ——— — ——————————— 14, 45-46, pi. 10

navicnloides — .. —— _ — _ .. __ __ _ _______ 14,46, pi. 10

* Page 

P[anopaea] cariboeus..._______«.__________.___—_____ 107 

Panope jjoKlfussii_____________________________._.. 12

reflexa.

parilis, FuSinus.

parva, Cnj|>ne—

Venus :>.....

—— ————————.——————.— ——————— 10

—— —— ——————————————————————— 13

.———————————_——————— —— —————— 128

....................................................^... 128

Parvilueina...—............... -.............. — ...._..............—... 78

multilineata.. —.________._____________________ 79

passus, Pectunculus.-____--------__-___-.___.---_.._.. 27

Pecten.-.————— ——.—————— —— —————————- ———— 30-31

clintoiuus. 

comparilis___. 

decemnarius_ 

dislocatus.___. 

dispala,tus—__. 

eboreus bertiensis. 

coipparilis—..

eb'oreus._________._________.___..___ 8,9,11, 

urbannae"nsis- —_-....-__-...--___--._---.—......_....

yorkensis-. _ ------- — — . _ .... _ . _ . ___ ______________________

ernests.mithi _ __ ..--.---. _ ... .. __ .. ___ ..--- __ _ _ _ _ ....

holbro$kii. --.-.-—. ——— . ___ — __ . ___ — .. — ... ... — — ....

irradians dislocatus— —— — _______________ — — __ __ — —

jeffersanius— ... ___ . _ .. __ . _____________ • ___ 6,7,9,11, 

edgecombensis _ .-----.—._ _ _ .. __ ...-...-.- _ .. _ . _ ... 8,9,

jeflersonius- -------- __ _ -------- _ .... _ --- _____ _ -.. _ ....

septenarius— — — — - —— — -... — — — -.— — ———————— .... —— .

mageilanicus. __ . 

marylandicus— — 

mortoni- — - __ .-- 

princepoides-— — 

raveneli-------—.

santai|iaria— . —— - 

mjddlesexensis. 

septenarius- — ....

viceharius— —— _ 

virginianus37

37

31

31

31

12

37

12,36

6,7

6

10

34

36

31

12,32

10, 12

8

34

32

37

38

39

37

14,30

6,7

34

(Amusium) mortoni— 

(Chlamys) clintonius.

-_f—— —:i:TM cbmparilis38 

30

14,39 

37 

37

10,31

, 36 

34 

31 

34 

32 

38 

38

pi. 4 

33 

14

14,32 

14 

30

14.37

14.38 

14,38 

14, ^6 

pi. 5 

14 

122 

27 

,26 

,.2727' 

pulvinatus___—.——— — _.._.__..___....._......_...._ 27

quinquerugatus.-.-— ——...._________________________ .27,28

51

deeemnarius..-------_____________._________ 9,

eboreus eboreus_—— —..__....-'--..-__._____,...........

ernestsmithi_.__..__'_______T_________________ 

gibbus,.——————————-__._-—--.—-_____________ 

jefiersonius septenarius—_..______________________ 

madisonius---------.----_-_._________...__.........

marylandicus_ — — _____._...._____________..

virginianus.———.________-_____.-......................

(Euv^la) raveneli...__.__._____._________________ 30,

(Lyrqpecten) jeflersonius....__._.__-___..._______.. 

jeffersonius septenarius._______.______.________.. 

niadisonius———.._..._.____.____________ 5,

(Nodipecten) ernestsmithi....__._..._....__..__...__.. ._...

(Pectin) raveneli.-—---.__._._.________________......

(Placdpecten) clintonius.___.. ______.______.__ 6,7,9,11, 

marylandicus__..._-..---.__........._..__——__. — 5,

virginianus ...———..._______________________ 9,10,

(Plagjoctenium) eboreus_ __.___________.__.______ 

gibbus-—..............................................^...-.. 14,31

planicosta.... ————..__.____..._________„_____

Pectunculus albidus——______.__________..................

americanus.———.---.--------._.________-.----....._.

laevis..———————,—_____.__.__.____.______......

sulcatus... 

tricenariustumulus—. 

undatus...

Pedalionmaxillatum..._____________________'... ___ 5,6,7,13 

Pelecypoda (incertaesedis)...._.-----.---.-.....__..._.-.—----.. 74,pi. 14

pellucida, Erycina_____._____._____________________-— 81 

peralta, Aleetrion..—....______.___...._______________ 13

percrassa, Mercenaria____...._._........................_._.... 132

Periploma...———————.——————————————. 42

antiqua.....__.__.___________.__..._______.___.. 42

inaequivalvis..-—- — ---._____._________.._------ 42

(Cochlodesma) antiqua....._._._-.--.__.______ — —. 42

perplana, Astarte___-___1________ ___________-____ 7,13 

Cardita-.——.---..-....——.......__——. ————— ——— .._... 71
176 INDEX

Page 

perplana, Astarte—Continued.

Qlans (Pteromeris)-._____.__—— —_____.__.-..-._.. 72,pi. 13 

Pteromeris__-------_._ T——_-.____---.._._............ 15

Petaloconchus sculpuratus-.___.__-__......________._.__ 8

Petricola.———————.———————————— — ————— 116-118

centenaria.--.___.___.-.___ —._....___„__..___.. 118,119

carolinensis...__________...______._________..__ 118 

eompressa_...___------------_-..._-_..___ ......__ 85

fornicata.______________..._.__.__.________.__ 117 

pholadiformls__.._____...._............................... 117

(Claudiconcha) grinnelli-.._____._........__---------------_ 117

(Petricolaria) carolinensis_......._....._-.__.........__-___. 118

pholadiformis__---------------------................................ 117-118

(Rupellaria) grinnelli..........................-. ——.-.......-... 15,117,pi. 15

harrisii......_____.________________-_.__._ 119

Petricolaria_.————- — .—_-_-_._-_._----_-_——— — _ — — . 117

Phacoides—. — ——— — ———————— ———— — —— — ———— 76-79

anodonta.__._____________.___.___.___..___. 9 

crenulatus—— —__._--------_._...__._--._.._.....__ 5,9,11

multistriatus. __ —_....._-_.__................_.____...... 12

(Cardiolucina) postalveatus_____._________._____ 15,77, pi. 13 

trisulcatus multistriatus—---------__-_———___.--.-.... 76-77, pi. 13

Phacoides (Cavilucina) trisulcatus....__.__._.__.__...______ 15

trisulcatus multistriatus-______......•_.._.___......_.... 9,15

(Lueinisca) cribrarius—.. „..__—— —— .„——————_____ 7,15,77-78, pi. 13

Phacoides (Lucinoma) contractus__....._...__________.._._ 7,10,11

contractus murfreesborognsis_----.-------.-----.------------.----.. 11

(Parvilucina) crenella__...........-......._-...__..-_...-......--.. 78'

multilineatus—___.___...._._________.__ 15,78-79, pi. 13

(Pseudomiltha) anodonta-_____-__-________.______... 6 

philanthropum, Calliostoma._._______.._____-___._.__... 9,10 

philippi, Pododesmus (Monia?).___....______...______.... 14,41,pi. 3

Phlyctlderaia---———— — —————— ———— ——————— ——— 81

pholadiformis, Petricola........._...._....____------_--.......-... 117

Petrieola (Petricolaria)----_...........__..._._........._._ 117-118

Pholas acuminata _____.______-_______...__..-_____._.. 141 

arcuata——____--------___.._-----_----------------__...... 141

candidus______-------__ ...._..._-..-...._.._......._.. 141

clavata.________._______._______________.____ 142 

costatus..____________._________.._________-_.. 141 

crispatus___..___..______.._.._._.............__ 142

cuneiformis___...__________________.___________ 143 

rhomboidea__...__--__---------___..__....._....____ 1"42

striatus—— „.————————_.———... —... — ———— — _ 142

piesa, Tellina (Moerella),_.__....______.______________,_ 96

pilsbryi, Turritella....._____________..___...________.. 9,13

Turritella variabilis—————— ———— _—_-—— — _-— — - 6,7

Pitaria (Pitaria) sayana.'--__________....______.____._.. 124

Placopecten.-—. —____-._____.______________...._____.... 37-39

plagia, Qlycymeris subovata.____--------_--------------------_------ 7,9

plana, Crepidula- —.. —. ......................................-.-............ 10

planicosta, Chlamys (Lyropecten)___.__________._..._...... 34,pi. 9

Pecten (Plagioctenium)._______.____-___....__-__...__ 14

plebeia, Turritella__.____________.._.____---------____.__ 6,13

Pleiorytis———...——. — —...... - — ..-..-...-..-...-.—........... 118-119

centenaria.___..._________._____...__...___ 7,10,119, pi. 15

ovata________-________-.___._--.______.___ 118

plena, Venus (Mercenaria)---------_---------___........................ 5,10

Pleuromeris.—____________....___.__-_.....___._.... 70

decemeostata.__________._-_____.__.._....._..... 70,71

tridentata...__-..__...-__----------_........_..__...... 15

decemcostata.--.____-_---------_——„_ — — _ — — _ — 15

pleuronectes, Ostrea-— — _ —— ------------------_........................ 39

Plicatula.-. — — ..- — .—- —.....'....................................i.. 39-40

marginata..—................................................ 9,10,14,40,1-1. 11

plicatus, Spondylus._._________-_-----_-------_______.... 39

pliouema, Caryatis.--.-__..—._.—._...._._............___.... 124

Pododesmus—-___-...--__-__,..._--------_....................... 40-41

decipiens...-._...._._-.---------.-..--.---------.-.---._____---.. 40

rudis.-------------------------------------------------------------------- 40

(Monia?) philippi———— — .„ — -.---..----...- — ..-.-.----... 14,41,pi. 3

polita, Angulus.____________._______..____________ 96

Tellina----.--—........ —..................... — ..........—....... 95

(Angulus)______.___-_.-___._..--_.--__---..___. 96 

Polynices duplicates___.________-----------_-----_-__.. 9

heros-_____.__________.___..________.__-___ 10 

polythalamia, Serpula._..----....----....-.----....----....-._--.....---... 143

postalveatus, Phacoides (Cardiolucina)-__-__...--.-........_... 15,77,pi. 13

preaequilibrata, Donax emmonsL---.--__.___._--------- 16,105-106, pi. 23

precursor, Crenella._._.......___________._____..____ 14,30,pi. 3

Mactra (Mactrotoma) fragilis.------------------------------- 16,109-110,pi. 18

princepoides, Pecten_.—.- —— ---------—.--. —— --------------- — ———.... 37

prodromus, Pandora (Clidiophora)___..__—____.______-_ 48,pi. 11 

proflcua, Tellina---------..----------------------------------------------- 100

propatula, Area _------_ ------------------------ —.__-----____---._ 22

Barbatia (Granoarca)--------..........„---...-.—.-.-..-..-....- 22-23, pi. 2

Pasre 

propeparilis, Fusinus...... ——.. ——— ---... ——. — —— ——————————— 7,9,13

propetene.lla, Tellina (Angulus).—. — ——.——.... —— - ——————.—.— 96

protracta, Anadara.- ——... — ——— ----- — — —— — —————————— 24, pis. 2,3

• Area..---------- — —— — — — — ————--——--—.——„.- 24

(Anomalocardia)......._ — —.. —— — -------- —— — — ——..—— 24

protracta, Donax_----------- — ------ — -_-. —. — —-. ———— — — —— -... 106

proxiina, Nucula..—--. — — --.—-——- ——— ————— 12,14, 19-20, pi. 1

Psammocolalucinoides—_-_--_—-- — --—— —— ——— — —— —— -.——— 80

Psammotea dubia_- ————— -. —— ------- —— — —— ——— .............—— 83

Pseudochama—__-—.__- — — _-— — — — - —— — — ------ —— —— —,- ——.. 89

corticosa__._______ —._____-_______—__———— 15, 89, pi. 13 

Pteromeris----. ——_- — ------------ — - — _... ——— --- —— ———. ——.... 71-73

perplana—--_-.--.--..-------.„.- ———— —— ————— - —— ——— --.... 15

abbreviata_-.....-.--.-.---------„------.----. — ——— ——..—— 15

Ptyehosalpinx altilis——.... —— _————————-—————-—————————— 10

laqueata.--------- —— ——.... ——— ------- —— - —— — — ——— —— — — — 10

pulchellus, Modiolus--—.-—--------- —.... —..-.---.. —— —. — — —— -. 9

pulvinatus, Pectunculus-—....—— ——————————————— -——————— 27

pygmaea, Venus.------- —— -------------- ———— -. ——— —— — — ———— -— 128

pyrenoides, "Drillia"-—_.- — —— ——— - — ——— ————— ——— -——— 10

Q

quadrans, Cardium.————.———————————————————————————— 91 

quadrata, Bulliopsis.-——... — ——- ———————— — ——— - —- — -————— 6 

'quadrigenerium, Cardium-- ——.. —— - — —— —— ------ —— — — ——— ——— 92

quadrisulcata, Divaricella_...._..—.. ——— -------------------————— 7

quinquerugatus, Pectunculus------- ——... ————-- — -------- —————.. 27,28

R 

radiata, Ervilialata...—...—.—.—————.—————— 16,116,'pl. 23

Tellina.--————————--——————— —— — - ————- 94

Rangia clathrodon__------ —— —— - — ————— - —.. —— ————— -——— 10

rappahannockensis, Astarte (Ashtarotha). ——. —— - ——— —— _. 14, 66-57, pi. 12 

Spisula (Hemimactra)----.-------------------------------- 16, 110-111, pi. 18

raveneli, Pecten___ — — — ———. — —— — ————— — ------ —— - ——— — 14,30

Pecten (Euvola). —..-.— — -——........... — -..„.——.....—. 30, pi. 4

(Pecten)..—- — - — - ——-————————-——- — --— 30

recurvus, Brachidontes (Ischadium).——-..—-.....--—————-.—— 29-30, pi. 1

Mytilus (Hormomya).- —. ——— -. ——— — —————— ——— ————— —— 14

redimicula, Fissuridea,...——— ————— ——— ——— ————————— -. 7,9, 10,11

reflexa, Panope. ———— ——— ——————————— — —— ——————— ———— 10

rcposta, Cytherea__—————— ————— —— — ———————————————— 123

Oallista(Callista)..--———-..—-.————.——.—————— 123

Dione..-—————————-—-———————————- 123

Macrocallista—--——..__————.—....—-------- ——.... 15, 123, pi. 19

reticulata, Tellina..———————— —————————————— 100

retusa, Corbula (Caryocorbula) conradi———————————————— 16, 140, pi. 23

rhomboidea, Aligena._...—._———————————————————— 15, 87-88, pi. 14

Fasciolaria___—-... ———— — ——— - ———— —— — — -- ———— -—— 8

Pholas--.- — --—————-— — — —————-—-——-—- — -— 142

Zirfaea——————— — ———————————————————— 142

rileyi. Venus.... ———— — —————————— ——— ———€-—— 6,10,130

Venus (Mercenaria) campechiensis__——.——————-———————— 130-132 

roanokensis, Astarte.... ——— - —— —— -- ——— —— —— — — ————— 14,53, pi, 12

Rochefortia—__ ————————————————— -————————————————— 86 

australis—..- —— — — —. —.———-- —. —— — — -.-..- —— —— ———— 85

stantoni.--.-- —.-. —— ------- —. ——.. ——. ———— - ——— — —— ——— 86

rogersi, Verticordia (Trigonulina)———-———.———————————— 14, 50, pi. 10 

rudis, Pododesmus-----——-———————————————————————————— 40

rugosa, Donax..--- — ----- —... —— -.... — — — — — - —... —— —...—— 105

rugosum, Busycon corona turn.-.-- — -. — —— — —— - —— - — —— —————.. 13

Rupellaria——————————— ——— —— ——— —————— — — — 116-117

rtistiea, Isocardia.. ——— — — —— —— - ——— —— — ——— —— — — —.—— 67

rustious. Glossus..------------ ——— — —— ——— — - — -------- — - —— ...... 67

St. Marys formation, description of.———————————————————————— 6-7 

fossils in_____________————————————————————————— 6-7 

Shattuck's zones in_ ——. — — ———— ——— ——— -- —.- —————— ——. 5,6

stratum A in......———————————————————————————————— 6

zone 1 in_—_—._____—. — ____—--———-_-.. — -.—-— ———--———-——- 6,7

zone 2 in ....________.._—__———————-——————————— 6,7

santamaiia, Pecten- —_ — - — - — — — — — — --_- — ------ ——. —— - — — — 6

sayana, Calloeardia—— — - — --------- —— — —— ——... — — —— _„. — _— 10,12

Callocardia (Agriopoma) ———— — —<-————————— 124-126, pi. 19

Cytherea—— — - ——— —— — —— --- — — -—————————— 121

Cytherea. — ——— — - —— — —— —— --——————-——------- 124

Dione.-- ——— —— — —— —— — ——————————————— 124

Meretrix...————— —— — ————— ————————-1——- 124

Oliva.__-____,____________________________ 10 

Pitaria (Pitaria)- — — — — ——— — —— —— —————— — - 124

Venus————— — ————— — ————————————————— 124

sayi, Tellina.___-----——————————————————————————————— 96

Tellina (Angulus).——— ———— ———--————————---— 96

(Moere.Ha)————————————————————————— 16, 96-96, pi. 17
INDEX! 177

Page 

scalaris, Anadara (Cunearca)—————— —————...__.....—__ 26, pi. 2

Area-...—......__._........_.........__......»__....__.__ 26

(Cunearca)______________.________________ 26

(Scapharca).._______________.______._______ 14

Seapharca..—________________.___.;__________ 26

Scalaspira strumqsa_.._____._______________________ 10

Scapharca lienosa______________._____.___________ 23

scalaris._______________...__.....________ 26

(Scapharca) callicestosa___._______________________ 24 

carolinensis___________.....___._..________ 25

Scaphella (Aurinia) mutabilis.________.........__._________ 9,12

schizopyga, Ilyanassa.. _________._.._......._.......___ 8

scintUloeformis, Cooperella.-...________--.-..._.--...._..___ 119

Scobinopholas__._____________.______.__._.___ 141-142 

scotica, Venus_._...____..___....____......__.... 51

sculpturata, Ostrea.________________.__......__.__ 8,9,10,12

sculpuratus, Petaloconchus............_._..___.__.........__.... 8

seutata, Corbula (Caryocorbula?).......------...__..-....--.-. 16, 140-141. pi. 23

Seila adamsi.______________________._.______.__ 8,12 

Somele—-„.—„—————————————————__.__—______.__.._ 100-103

bella—.----.----.----..----........-........,......_..................... 101

beDastriata—— ...—... —........................................ 16,102, pi. 17

cancellata._____._____________,_______________ 102 

lata......^-................................................................ 102

nexilis......__..________..............._......_____.... 102

nuculoidea.__________________________._____ 102 

nuculoides-___________________....________.__ 16,102

subovata.-.—----.-—-._...................................... 9,10,100-101

subovata alta.__._____________.___________ 16,101, pi. 17

(Semelina) nuculoides______. _____ _______. __ 102-103, pi. 17

Semolina...__._-..._......._-................._._...__....__ 102

nuculoides.-._____________.......___.________...... 102

semiaspera, Diplodonta__..._.._........._--.-..___._....__. 81

Septastrea marylandiea_...--._-_.----_._____........_...._....... 9

septenaria, Chlamys (Lyropecten) jeftersonia.____.................. 33,34, pi. 4

septenarius, Pecten_...__.......__......_._..___...... 34

jeffersonius. —...___........__......_..................__ 34

(Chlamys) jeffersonius____......_...__._..______ 34

(Lyropecten) jeffersonius.______....________________ 14

Serpula polythalamia..______________. _______________ 143 

sexdentata, Ilyanassa granifera____._...__..____._____ 12

Siliquaria——..'——._...._._......................................._ 107

earolinensis..——___.__________..______________ 107,108

eariboea__.________________________________ 107

similis, Mactra..________________._______________ 111

Spisnla (Hemimactra)..__....... — .......................... 16,111-112, pi. 22

simplex, Terebra.______________.____.._____________ 6,13 

sinuatus, Crassatellites..._________._________________ 61 

Solarium nuperum._..._______._____.__________.__ 11 

Solecurtus cariboeus_________.__......________.____ 107

(Tagelus) gibbus______._____________.___....___ 107

Solen.. ———————— —— ————— ——— ——— ——— ———————— 108

cariboeus._.*.'___.._________________.________ 107 

gibbus________.________._____.__...______ 107 

guineensis.-.-___-..--.__.-.--......_____.___..._ 107

viridis...__.—..-.......—.-.....-.-....................... 16,108-109, pi. 23

solida, Maetra______.______...._.________________ 110

solidissima, Mactra____--.-._..._.......___...._____.__.... 110

soror, Diplodonta-__..__-______-----_____________.__„. 81

Diplodonta (Phlyctidenna).. ___ _ ___________ ___ 15,81, pi. 14

Lucina...._r_...._.__......._-..._....._-...___.... 81

spatha, Mesodesma..._______.______.____.__._ 16,115,pi. 18 

speciosa, Ctena_____..._-____._____...._______ 15,75,pi. 13

spinosa, Bamea___.......__._.........._....._...__..._ 141

Spisula...—.—.———————————————— —————— 13,110-113

confraga._..___________.._.________.______._ 6 

delumbis_.______....______..______....___.___ 8,12

(Hemimactra) duplinensis..._______.___.__.._______ 112 

magnoltana.___________________.__________ 114 

modieella———-------- — - — — --—-.- — --._- — — --.-_ 16, lll.pl. 23

modicellaalta——-. — --...„--.-.-..-...-.-.-.... — ...... 16, 111, pi. 23

rappahannockensis..._____.______________... 16,110-111, pi. 18 

similis.-.-------.-------.-.----__—————._.————— 16,111-112,pi 22

(Mactromeris) bowlerensis.._______ ...1__....___.. 16,112, pi. 18

duplinensis...............................................__ 112-113, pi. 22

Spondylus plicatus,--------____..____....._._____._____ 39

Sportella..................................................................... 83-85

calpix..————— — -.. — _—————_—————._——————_ 15, 84. pi. 14

compressa.-_-.---..--____....._..._..._..__..___ 15, 85, pi. 14

constricta___——___——___.________ _ ________ 15, 83-84, pi. 14 

gibberosa..........................__.—..............._.... 15,84-85, pi. 14

waccamawensi?.--—-_-.---..________..........___..... 15,85, pi. 14

staminea, Area...____..,.__..__.._______.._________ 5 

Standella congesta...._____------_,.r .......____....______. 113

stantoni, Mysella_______________________________.. 86, pi. 14 

Roehefortia...-__..___ ._____.____............_._..__ 86

Pajte

stephensoni, Astarte..__———__————..————..—————— 14,54-55, pi. 12 

stevensoni, Caecum.......———_—————.————————————————— 10

Stratford Cljffs, Va., sections at___—____..._.__————————— 5 

striata, Aligena..———. ———————————.——————————————————— 87

Chama..——————————————————————————— 18,88, pi. 13

striatus, Pholas______——.._———..—————.—————————— 142 

strumosa, Scalaspira.. ——————.—————————————————————.. 10 

stultorum, Mactra___...____———__——.....——————————— 109

subdiaphana, Oedalia..__—...—..————.—————————————————— 119 

sublineatum, Cardium......———.——————————————————— ———.. 94

Cardium (Laevicardium)___—.......————..—————————— 15,94

sublineatum, Laevicardium.....——————————————————————— 94,pi. 15

subobliqua, Syndosmya...—————,—————————— ——————————— -- 101 

subovata, Amphidesma.....——......—————.————————————————— 100

Abra (Amphidesma).....__________._____——...-.———— 101

aiycymeris-...__.._-----__——..__.............——.—— 6,7,10,12

Semele................—............„..„.—...........„.—.. 9,10,100-101

subreflexa, Abra—————__———:._______.__._ 16,103-104,pi. 17

Amphidesma____________——___———————————————.'-. 103 

subvexa, Diplodonta__..————..—————————————————————:. 5 

sulcata, Corbula________________________———.-_——— 139

Modiola—-——————————————.....———————— 29

sulcatus, Pectunculus__—— ——————————————— ————————— 51 

sulcosa, Lirosoma____...____——___————.—————————— 10,11 

surryensis, Crassatellites meridionalis______————..——————————— 6,7 

symmetrica, Astarte.-__——...__—......._-.—————... 10,13,14,51-52,pi. 12

Syndosmya constricta.....— ——...——..———————————————————— 83

subobliqua...^_——.———————————————————————————— 101

T

taeniopleura, Cardium. 

Tagelus—-——————.

..——..———————————————— 13

....... ................——....——.——————. 107

gibbus..——————————————————————. 16,107-108, pi. 22

carolinensis.-._———___._____——„__—.—. 16,107,108, pi. 22 

Tapes grus.._————...—————.——————————————————————— 128 

Tellina....——.—————.———————————.——..——..———— 94-98

calcarea._—....._———.——————————.———————————— 98

dcclivis......————————————.—————————— 12,94,95

donacina...----.__..————————.——.———————————————,- 94

egena..——————————————————————— 16,98, pi. 17

fluminalis_.____——.——————...——————————————— 64 

inaequivalvis—.___——......————...—————————————— 44

lusoria_...——————————————————————.————————-—— 98 

polita.—————————————————————.......————— 95

proflcua. —————...............——.————————.—————— 100

radiata..—————..———————————————————— 94

retieulata———————........................'———.—————.—.- 100

sayi---———--———————————————————————— 96

(Angulus) declivis.__————.—————————————————————— 95 

dupliniana_____.____———__———————————————— 96 

macilenta___________________.___————————— 97 

polita—.--.———.——.. ————.——————.————————- 96

propetenella..-._————. ———————————— >. ——————— 96

sayi-- — .——————————————————————————— 96

(Moerella) ealpix.........————............——————...... 16,98, pi. 17

declivis..——.—.———— ——————————————————'94-95

dupliniana________________________________ 96-97 

macilentai-___......___.—.........———..———————— 97, pi. 17

piesa.-..----..__————.————— —————————————— —— 96

verdevUla..._....._...„._.._....._..__..„.__.. 97-98,pi. 17

sayi...————————————————————.......... 16,9fr-96.pl. 17

(Peronaedermjf) lusoria______—~___—————————————t--- 99 

(Peronidia?) egena.— —-——_-_—————————————————————— 98 

tenera, Macoma. „""-"——__——————————————————————————— 98 

tenuis, Mactra-...'-__________——___——————————————— 103 

tenuisculpta, Lucina.__________._____..—__—————————— 78 

Terebra.——————————........———.——...——.———.—————- 8

simplex_______________...____————.—————————— 6,13 

Teredo calamus____________—--___——————————————— 143

fistula.--....----.__...__.......__———_____-----__-___ 143

terstriata, Turritella————_____-----___——___——-————---- 13

texasiana, Cytherea____———__——.——.———————————— —— - 124 

thallus, Cadulus,—..——.————————————————————_—————— 9 

Thraeia—————...—.....——... .„.....——...——.....—————— 42-44

conradi——............———.„————...——...————..... 14,43, pi. 10

corbuloidea_____________————.——————————————— 42 

declivis—--——————.:.-——_____._____.—————- 43

maddelysensis.___-...___....———————————.———— 14,44, pi. 10

transversa___——.—.——————.__.__—————-———— 14,43-44, pi. 10 

sp—————...——————....———————————.—————— 6

Timoclea........————————————————————————— 128

Trachycardium______...____—...___.....—.—....————.— 91-93

emmonsii__________________________————————— 92 

isocardia.____________________________—-___ 91-92, pi. 15 

muricatum__.......__....————_——.....————-— 92-93, pi. 15

transversa, Thraeia———————————...———,——.———.... 14,43-44,pi. 10
178 INDEX

Page

transversus, Artemes.____.________..______..._.____ 122 

trapezia, Chama._. ______________.________. _.____ 69 

trapezoidalis, Venus...____..._....__.._....._........_....... 128

trlangula, Bornia._ _____ _. ___________. _____ 15,82-83, pi. 14 

Kellia.._—————————————————————— ———_........ 82

tricenarius, Pectunculus............._..________..________ 27

tricostata, Ecphora__________________.__—.________ 5

tridacnoides, Cyprina. _____________________________ 132

Mercenaria________________.________________ 132

Venus—————————— ——— —— ————————————— 10,11,130,132

(Mercenaria) campechiensis...______________.. 15,132-133, pi. 21

tridentata, Actinobolus___ ______.___________________ 70

Cardita———————— .——— —————— ————.. —......... 70,71

(Venericardia)_____.___.____________....._..._ 70

Qlans (Pleuromeris)______.______________________ 70-71 

Pleuromeris......___..._..._._...______.__ 15

Venericardia________________________________ 70

(Pleuromeris)_.____ ___.___________.__.__ __ 70,71

trlgintinaria, Eontia.____________.______________.___.. 9

Trigoniocardia.._____.______._.__________________ 93

(Americardia) media...._______.__________________ 93

Trigonulina..-...—......................................................... 50-51

ornata_____________..._____________.______... 50

trilineata, Pandora.___________.___.______________.. 48,49

Pandora (Clidiophora)....———— ———————...—......... 48-49,pi. 11

triquetra, Mactra—._. _________________ _______ ___ 113 

Mulinia. —.............................................................. 113

trisulcatus, Phacoides (CavUucina)_____.________. ________ 15 

trossulus, Urosalpinx...__ *....___._._...____.-..---------..._ 8,11

truncata, Mya._______________.___.__....___._..._ 138

tumulus, Qlycymeris......_____...____.______.__ 6,13,14,27,pi. 1

Pectunculus.----__...________.._-,..--._.-.---..----. 27

tuomeyi, Qlycymeris subovata.._________.________....__ 9,11

Pandora (Clidiophora).__.— ———— ———————— ————. 48-49, pi. 10

turgidulus, Crassatellites...-.-______'..._.______________ 5 

Turritella-- —... ——_.......__......_„......_„—...——..._„„____._ 8

alticostata.............................................................. 9,10,11

pilsbryi................................................................... 9,13

plebeia.-.-.-....----._--.---——.-——_..——-.--———.____.— 6,13

carinata. _..——————_.———_———————_.————._——— 7,13

terstriata.___________________________________ 13

-variabilis_______________,_________>.__._____ 6,12

pilsbryi_____.____________.______________ 6,7

U

undatus, Pectunculus.._____________._________________ 28 

'undulata, Astarte__..__________._.___,..._....__... 57

Astarte (Ashtarotha).....—...................-—.....——... 9,14,57-58,pi. 12

undulatus, Crassatellites....---.-....-----..--..-..-..------..----.--- 7,9,10,11,12

urbannagnsis, Crassatellites undulatus.________,___________ 6

Peeten eboreus..___.._.__..._...__--.-.__.__..... 6,7

"Urosalpinx trossulus......._____._..__.________....___. 8,11

Uzita chowanensis_..__ —._......__......—L__...__.......... 12

vaginulata, Astarte undulata.._______...----..---.-.___._..__ 58 

Astarte (Ashtarotha) undulata...-..-------—----------- 6,7,9,14,58-59,pi. 12

variabilis, Donax______.____________________________ 106 

Turritella—-_———- ———.-——.. —— —————.—— .—— ——.. 6,12

v61aini, Mysella-.—————.————————————————— 15,86, pi. 14

Venericardia granulata.............................................. 6,7,9,10,11,12

perplana abbreviata....—...——-.... —..———_——---.-....._... 9

tridentata....- —.__——__...._——_——..———_..—__— 70

(Pleuromeris) tridentata___________________.__..____ 70,71 

tridentata decemeostata.1.._..____...___--...-__..__... 71

Venus.. ——-. — ——————————————— —— ———. —— ——.. 130-135

campechiensis.-—-__—___.__....__...__——__....__.. 132

campechiensis carolmensis________..___.___..___.___. 132 

cancellata...._______________*_______________ 127

concentrica.————————————-———•————————— 120,122

cortinaria._____________________________________ 127 

cribraria———————.—————————.———————i— 128

deformis.------_——.———————— — — —— —————_—. 132

difiormis.-...—-__.....___.———.————.—— —— ————- 132

dysera_._______---..---..-..-——...--.--_. —....——_—— 127

erycina—___..___—__—.———.—————————..————— 123 

gallina—————————————————————— .——————— 129

gemma.._______..___..._—.... ——— —— ————————— 135

gigantea___....__——_——.—————————————————————— 122

lapicida____._____________—...————————————— 116

latisulcata__—__——.————————————————————————— 65 

lithophaga.————————... ———————————————————— 116

Page

Venus—Continued.

lupina—.—_—..__—.———.———...————. ———.————r 79 

mercenaria notata...... — ———.. —— ———.. — — —————————— 130

nimbosa___________________.___.___.___..__. 122 

notata..—-.—————————————_——————————„— 130

ovata_—___..__—__——__——_————————.—..——— 128 

parva_——_ —..__------- —.—— —.... ——— ————— ———— 128

plenainflata...——— ———————. ———————————— 134

nucea_______._________—_——__—— —.——_— 134 

pygmaea..._ ———————— „ ———————— - ————————————— 128 

rileyi.. ————.———— — —— -- — ——— — —————— 6,10,130

sayana___..__--.-._._..—.._..._------- —— —— — ———_.— 124

scotica_—————-----—-..———i—————————————————— 51

trapezoidalis-__-__ ——__—_——.——————————————— 128 

tridacnoides.. —————— — —— ————————— ——— ——— 10,11,130,132

verrucosa_._ „ —._____------____._——..———............ 130

(Mercenaria) berryi.--————— —— ——————————— 15,133-134, pi. 21

campechiensis carolinensis._____.__.....__——...... 15,132,pi. 20

rileyi... — - ——————————— ———————. ——— —— 130-132

tridacnoides—.—— —— ——————————— — —— 15,132-133,pi. 21

mercenaria notata._.__..__——_————————— 15,130, pi. 21

plena_____.__-.___.__________..______— 5,10

inflata—— ————————————————————— 15.134, pi. 21

nucea——— ———— — — —— —————————————. 134-135, pi. 21

venustum, Cardium.._......__... —...—__-..-.--——.....—__... 93

verdevilla, Cardita arata_....__——__—....——.——————————— 9

Carditamera arata________.________________ 15, 69, pi. 15 

Gemma.--—..——————————— ——— -—————..... 138, pi. 19

Tellina (Moerella?)——.. ———— —— ———————————— 97-98, pi, 17

verrucosa, Venus......___.__—_——————————————————... 130

Verticordia....————-——————— — —.——————..——— 80-51

cardiiformis__..._.—... —— ------ ———.————————————— 50

emmonsii__..__...________....__—_——....——....— 80

(Tiigonulina) chowanensis_______.___——..———__— 14, 51, pi. 10 

emmonsii.____________________-______ 14, 50-51, pi. 10 

rogersi———.——————————————————— 14, 50, pi. 10

vicenarius, Pecten——_——.... — -------- ————— ——— ———————— 36

vicina, Astarte_———-————————————————————1———————— 52 

Virginia, localities in—————— ——— —— — .————————————— 17,18

Miocene stratigraphy of, nomenclature of..._..__——...__ 3 (table 1), 4

summary of___——__..—.———————————————————— 2,18

virginiae, Area__..._——..—— — ———————————————————— 7,13

Pectunculus-.;——————————1————————————————————— 26

virginiana, Chlamys (Placopeeten) — .—————————————.—— 38-39, pi. 4

Gemma magna__________________-_______ 16, 136, pi. 19

Macoma————————...———...——....................... 16,98-99, pi. 17

virginianum, Cardium._...__..... — .__.__—_——._...._ 7,9,10,91

Cardium (Cerastoderma)—————.———————————————————— 15,91

Cerastoderma______...———_—————-——————————— 91, pi. 16

virginianus, Peeten-—__——..— —...——————————————————— 38

Pecten (Chlamys),——————————————————————— 38

(Placopeeten)—————————————————————————— 9,10,14,38

virginicum, Calliostoma__—__—__———————————————-—— 10 

viridis, Solen..———..... .............——...————............ 16,108-109, pi. 23

W

waccamawensis, Ostrea___._..—_1—-———————————— 14, 41, pi. 3 

Sportella——————————————————————— 15, 85, pi. 14

watsonensis,Pecten eboreus—————.. ————————— —————————— 6 

wilsoni, Anadara callicestosa___...._———.————————————— 24-25, pi. 3

Yoldia——————......—-....————————————....———— 21

arctica-———————————————————————————————————— 21

hyperborea_.——. ————————————————————————————— 21 

laevis—..-———————————————————— 10, 14,21, pi. 1

"limatula".. ——————————-—-————.——...——-———— 21

yorkensis, Diplddonta...———————————————————————,———— 119

Pecten eboreus_ ———.—————————————————————————— 10

Yorktown formation, bed at Biggs farm in.——.— —————————— ——— 8-9

description of...—._——....—————..—....—————..„.——.— 7-13

fossils in——————————————...........——....—————— 7-13

sections in___———————————————————————————————— 9-11

zone 1 in_____.....,.—————————————————————————— 7-8

zone 2 in——————————————————————————————————— 8

zealandica, Anomia——————————————————————————————— 41 

ziczac, Pecten..—-.:——...———...——————————.———————— 30

Zirtaea.—————————————————————————....———— 142

rhomboidea————————....-——————————— ———— 142, pi. 23

Zirphaea—————————————————————————————— 142

o