Some Upper Miocene and 

Pliocene(?) Ostracoda of 

Atlantic Coastal Region for 

Use in Hydrogeologic Studies

GEOLOGICAL SURVEY PROFESSIONAL PAPER 821
Some Upper Miocene and 

Pliocene(?) Ostracoda of 

Atlantic Coastal Region for 

Use in Hydrogeologic Studies

By FREDERICK M. SWAIN

GEOLOGICAL SURVEY PROFESSIONAL PAPER 821

Descriptions, illustrations, geographic 

distribution, stratigraphic ranges, and 

environmental aspects of microfossils

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1974
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

V. E. McKelvey, Director

Library of Congress catalog-card No. 74-600014

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 - Price $1.85 (paper cover)

Stock Number 2401-02533
CONTENTS

Abstract __________-_______--___-_--- -- 

Introduction __________ ______ _ _____ _

Acknowledgments ____ ________ __ 

Stratigraphic summary _______ __ -

Ostracoda from deposits of Pliocene (?) age ______

Ostracoda of the Yorktown Formation _____________

Upper Yorktown _ _______ ____ __ 

Middle Yorktown _________ _ __ --

Lower Yorktown _____ ________ __ -

Ostracoda of the Duplin Marl ______ ____ _ ____

Upper Miocene Ostracoda from wells in the Atlantic 

Coastal Plain _______ _________ ___________

Summary of Ostracoda distribution in upper Miocene 

and Pliocene of Atlantic Coastal Plain based on 

collections studied herein _______ __ __ ___

Systematic descriptions _ ____ __ __ - 

Family Paracyprididae _______ ___ 

Genus Aglaiocypris _ _ _ __ - 

Family Pontocyprididae _______ __ _ ______

Genus Propontocypris __ _ _ - 

Family Bairdiidae ______ __ ____ 

Genus Bairdoppilata ______ ____ _____

Family Cytherideidae ____ ______ ____

Subfamily Cytherideinae ___________ _

Genus Haplocytheridea _________ _ 

Genus Cytheridea ____________ __

Subfamily Eucytherinae ________________

Genus Eucythere _______ ____ _ __

Subfamily Neocytherideidinae ____________

Genus Cushmanidea ____________

Genus Pontocythere _______________

Genus Neocytherideis _____________

Family Cytheruridae ___________________

Genus Cytherura ____________________

Genus Cytheropteron __________________

Genus Hemicytherura ________________

Genus Paracyt her idea ________________

Genus Shattuckocythere, new genus ______

Family Brachycytheridae _________________

Subfamily Pterygocytherinae _________

Genus Pterygocythereis ____________

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Systematic descriptions Continued

Family Cytherettidae _________ 

Genus Cytheretta ____ __________

Genus Protocytheretta _ _ __. 

Family Bythocytheridae _______ ___-

Genus Jonesia ___________ ___.

Family Xestoleberidae _____ ___ _ -

Genus Xestoleberis ____________.

Family Leptocytheridae _____________

Genus Leptocythere _________.

Family Loxoconchidae ____________.

Genus Cytheromorpha __________

Genus Loxoconcha ___________

Family Paradoxostomatidae ___________

Subfamily Paradoxostomatinae ___- 

Genus Paradoxostoma _____.

Family Trachyleberididae ____________

Subfamily Trachyleberidinae ____-

Genus Murrayina ________.

Genus Actinocythereis _______

Genus Cletocythereis _______.

Genus Costa ____________.

Subfamily Echinocythereidinae __- 

Genus Echinocythereis ________.

Family Campylocytheridae _________

Genus Bensonocythere __________

Genus Campylocythere ______.

Genus Acuticythereis ____________

Family Leguminocythereididae ______.

Genus Prodictyocythere, new genus 

Family Hemicytheridae _____________

Subfamily Hemicytherinae ______

Genus Radimella _________

Genus Aurila ____ _______

Genus Caudites ______________

Genus Muellerina ___________

Genus Orionina ___________

Subfamily Thaerocytherinae ____

Genus Thaerocythere ________

Genus Puriana ___________

References ____________________________

Index ____________________________

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ILLUSTRATIONS

[Plates follow index]

PLATES 1-13. Upper Miocene and Pliocene (?) Ostracoda. 

FIGURE 1. Location of sample sites _____________

Page

2

III
IV UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

TABLE

Page

TABLE 1. Upper Miocene and Pliocene (?) Ostracoda from outcrop samples in North Carolina and Virginia ____________ 4
SOME UPPER MIOCENE AND PLIOCENE(?) OSTRACODA OF

ATLANTIC COASTAL REGION 

FOR USE IN HYDROGEOLOGIC STUDIES

By FREDERICK M. SWAIN

ABSTRACT

Upper Miocene and Pliocene(?) outcrop samples from 

North Carolina and Virginia yielded 63 species and seven 

subspecies of Ostracoda. The stratigraphic distribution of the 

species indicates the presence of an assemblage, the Aurila 

conradi-Thaerocythere schmidtae assemblage, that also extends into the Pliocene in southern North Carolina and South 

Carolina. A subassemblage, the Radimella cvnfragosa subassemblage, represents the upper Miocene and Pliocene in 

southern North Carolina and in South Carolina. T. schmidtae 

appears to represent a cooler water subassemblage of the 

upper Miocene in northern North Carolina, Virginia, and 

southernmost Maryland.

Two new genera, two new species, and one new subspecies 

are described herein. The new genera are Prodictyocythere, 

n. gen., and Shattuckocythere, n. gen. The new species are 

Murrayina macleani, n. sp., and Prodictyocythere trapezoidalis, n. sp. The new subspecies is Pontocythere agricola 

duopunctata, n. subsp.

INTRODUCTION

As a part of a U.S. Geological Survey research 

project dealing with the permeability of sedimentary 

rocks in the Atlantic Coastal Plain, the Ostracoda 

have been studied from many surface localities and 

well samples (fig. 1).

The present paper describes the upper Miocene 

and Pliocene (?) Ostracoda obtained from outcrops 

in the Atlantic coastal region in the area extending 

from North Carolina to Maryland. Other ostracode 

faunas of the region will be discussed in later papers. 

This paper represents the fourth in a series that 

records the results of the Ostracoda study; the 

others are Swain and Brown (1964, 1972) on Lower 

Cretaceous, Upper Jurassic (?), and Triassic Ostracoda, and Swain (1968) on Tertiary Ostracoda.

ACKNOWLEDGMENTS

P. C. Sylvester-Bradley, University of Leicester, 

kindly arranged for the scanning electron microscope photographs on plates 10-13, and Frederick J. 

Gunther prepared most of the transmitted light

photographs on plates 8 and 9. H. J. Oertli and W. A. 

van den Bold provided the writer with many helpful 

suggestions.

The scanning electron microscope and optical 

microscope photographs on plates 1-7 were made at 

the University of Delaware with the assistance of 

Takako Nagase.

STRATIGRAPHIC SUMMARY

The ostracode-bearing deposits of Miocene and 

Pliocene (?) age in North Carolina, Virginia, and 

Maryland are represented in part by outcrops of the 

Yorktown and Duplin Formations and in part by 

sediments of late Miocene age that do not crop out. 

These sediments attain a maximum measured thickness of 590 feet in a well in Pamlico County, N.C. 

They thin to the north, to the south, and to the west 

of Pamlico Sound.

The Yorktown Formation was named by Clark and 

Miller (1906) for exposures along the James River 

at Yorktown, Va. The formation consists of white 

and light-gray fine- to coarse-grained molluscan 

sands, in part silty, argillaceous, and glauconitic; 

white and light-gray sands; argillaceous, coquinoid, 

porous, coarsely crystalline limestone, sandy molluscan shell beds (shell marl) ; and light-gray and 

brown clay (Swain, 1952; Brown, 1958). The Yorktown Formation thins to a f eatheredge along the outcrop belt in central North Carolina and in the coastal 

areas in Virginia and Maryland. The thinning is 

chiefly erosional, as indicated by the numerous outliers in the inner Coastal Plain and in adjacent areas 

of the Piedmont province to the west of the dominant Yorktown outcrop belt. North of Maryland, the 

Yorktown Formation is transitional to the Cohansey 

Sand that comprises virtually unfossiliferous beds 

(Spangler and Peterson, 1950; Owens and Minard, 

1960). In North Carolina the Yorktown Formation 

is underlain chiefly by beds of Cretaceous, Paleocene, 

Eocene, and middle Miocene age. In the restricted
UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

37°

SAMPLES

. A1-A6; Maddry's Bluff, Hertford Co., N. C. 

. B1, B2; Meherrin River, Hertford Co., N. C. 

. C1, C2; Suffolk, Nansemond Co., Va.

D1, D2; Suffolk, Nansemond Co., Va. 

. E; Tar Ferry Landing, Hertford Co., N. C. 

. H1-H4; Black Rock Landing, Bertie Co., N. C. 

. K1-K4; Petersburg, Dinwiddie Co., Va. 

. LI, L2; Petersburg, Dinwiddie Co., Va. 

. M1-M3; Sunken Marsh Creek, Surry Co., Va. 

. N1, N2; Mt. Pleasant Plantation, Surry Co., Va. 

. PI, P3; Fergusson's Wharf, Isle of Wight Co., Va. 

. R1-R4; Morgan's Beach, Isle of Wight Co., Va. 

. S1-S5; Moore House Bluff, York Co., Va. 

. T1; Urbanna, Middlesex Co., Va.

U1; Rappahannock River, Middlesex Co., Va. 

. VI; Rappahannock River, Middlesex Co., Va. 

. Z; Chickahominy River, Hanover Co., Va. 

. Meherrin River, Hertford Co., N. C. 

. Meherrin River, Hertford Co., N. C.

19 -J?

_VIRGINIA_ |_ 

NORTH CA"ROLINA^\X \

36"

FIGURE 1. Location of sample sites.
OSTRACODA OF THE YORKTOWN FORMATION

area, Albemarle and Pamlico Sounds, it is underlain chiefly by the Pungo River Formation of middle 

Miocene age. (See Kimrey, 1965.) In Virginia, the 

Yorktown Formation is underlain chiefly by beds of 

Cretaceous, Paleocene, Eocene, and middle Miocene 

age. In the central and northern coastal areas of 

Virginia, the Yorktown Formation is underlain primarily by the Calvert Formation and, to a lesser 

extent, by the St. Marys Formation of middle Miocene age. In Maryland, the Yorktown, or its Cohansey Sand equivalents, rests on the St. Marys Formation and on the Calvert Formation that is transitional to the Kirkwood Formation to the north. In 

southern North Carolina the Yorktown Formation 

grades laterally into the Duplin Marl (Stuckey and 

Conrad, 1958; Stuckey 1958).

The Duplin Marl was named by Ball (1898) for 

exposures in Duplin County, N.C., near Natural 

Well, southwest of Magnolia (Keroher, 1966). The 

Duplin consists of shell marl, clay, and sandstone as 

much as 100 feet thick in North Carolina according 

to Cooke (1945), but later authors have included the 

beds with the Yorktown Formation, or have referred 

to it as upper Miocene, undifferentiated (Swain, 

1952; Brown, 1958). For example in the Cape Hatteras well, the deposits in the interval from 160 to 

250 feet was found by Gardner (in Swain, 1952, p. 

8) to contain faunas "closely allied to those from 

the Duplin surface outcrops." The upper Miocene in 

that well extends from 160 to 391 feet. According to 

Malde (1959) the Duplin in South Carolina is not a 

well-defined unit lithologically, but is more of a biostratigraphic unit of late Miocene age. From North 

Carolina, it extends into eastern South Carolina, 

eastern Georgia, and Florida where it rests on rocks 

ranging in age from middle Miocene to Late Cretaceous. The Duplin is overlain by Pliocene or by 

Pleistocene deposits in its areas of occurrence. The 

Waccamaw Formation of late Miocene to early Pliocene age in southern North Carolina and northern 

South Carolina (Swain, 1968) is very similar lithologically to the Duplin beds, and the two formations 

may be in part lateral equivalents.

The upper Miocene deposits of New Jersey, 

Delaware, and most of Maryland do not commonly 

contain Ostracoda, except in a few wells near the 

coast; the upper Miocene has not been found in New 

York. The upper Miocene ostracode faunas of South 

Carolina and other southeastern States are being 

studied. Several papers on these faunas have already appeared, notably those by Howe and others 

(1935), Puri (1954), and Pooser (1965).

OSTRACODA FROM DEPOSITS OF 

PLIOCENE(?) AGE

Three collections obtained by Thomas G. Gibson 

are possibly of Pliocene age. These are: (1) in the 

upper part of a bluff 150 yards south of Colerain 

Landing on the western bank of Chowan River, 

Bertie County, N.C. (Gibson's samples G-l and G-3 

in ascending order), (2) in bluff at a point 200 

yards south of Colerain Landing (Gibson's samples 

F-l to F-5 in ascending order), (3) Mount Gould 

Landing on western bank of Chowan River, Bertie 

County, N.C. The species of ostracodes from these 

Pliocene (?) deposits are listed in table 1.

The following species from the Pliocene (?) localities in table 1 have not been recorded in this area in 

deposits as old as Miocene: 

Cytherura cf. C. gibba Miiller, 1785 

Xestoleberis cf. X. aurantia (Baird, 1838)

The remaining species from the Pliocene (?) also 

occur in the Miocene of this region. Lithologically 

the Pliocene (?) beds at the two localities mentioned 

above are darker brown in color and are more of a 

shell hash than is the Yorktown Formation in this 

area.

OSTRACODA OF THE YORKTOWN

FORMATION 

UPPER YORKTOWN

Two collections provided by Thomas G. Gibson 

were designated by him as representing the upper 

part of the Yorktown Formation. These are: (1) in 

a bluff on the western side of Chowan River at Black 

Rock Landing, 1 mile north of Highway 17 bridge, 

Bertie County, N.C. (Gibson's samples H-l to H-4 

in ascending order), (2) roadcut on south side of 

road leading to Tar Ferry Landing on Wiccacon 

Creek from Harrellsville, Hertford County, N.C. 

(Gibson's sample E), the exposure of 6 feet of yellow 

sandy beds is about 100 yards south of the old ferry; 

megafossils are common, especially Mercenaries and 

Pectens; sample was taken 3 feet above base of section. The ostracode species obtained from the upper 

Yorktown localities are listed in table 1.

No ostracode species are restricted to the upper 

Yorktown in the present collection.

One species occurs in the upper Yorktown, as 

designated by Gibson, and has been recorded in 

younger deposits by other workers but is not known 

to range into middle or lower Yorktown: Protocytheretta sahnii Puri, 1952.

One species was found in the upper Yorktown or 

in older deposits but not above the Yorktown: Paradoxostoma robustum Puri, 1954.
4 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

TABLE 1. Upper Miocene and Pliocene (?) Ostracoda from outcrop samples in North Carolina and Virginia

	Pre- Lower Middle Upper

Species York- York- York- York- Duplin Plio- Holo-

	town town town town cene cene

Actinocythereis exanthemata exanthemata (Ulrich and Bassler) X X X X X X ?

exanthemata gomillionensis (Howe and Ellis) _ __ X X *X

Acuticythereis laevissima punctata Edwards __ X __ X *X

laevissima Edwards ______________-_______ ? X X X X X X

Acuticythereisl sp. immature ____ _ _ X X

Aglaiocypris sp __________ __ X

Aurila conradi (Howe and McGuirt) ____ ___ _ X X X X X X

Bairdoppilata triangulata (Edwards) _____ ____ _ __ _ X X X X

Bensonocy'there whitei (Swain) X X X X X X X

Campylocythere laeva posteropunctata Edwards _____ _ _ X _ X X

laeva Edwards ______________________________ X X X X X X

sp ___________________________ __ X X

Caudites choctawhatcheensis (Puri) _________________ _ __ __ __ 2 X

sellardsi (Howe and Neill) _ ____ __ __ __ _ 2 X

Cauditest sp _____________________ ___ _ _ _ X X

Cletocythereis mundorffi Swain (and subsp.) - -_- X 3 X __ X X

Costa barclayi (McLean) _________________________ _ __ X _ X *X

Cushmanideat agricola (Howe and Hough) _ _ _ _ _ __ _ 2 X

fabula (Howe and Dohm) ____________ __ _ X X

ulrichi (Howe and Johnson) __ __ X X X X _ _ X

Cytherelloidea umbonata (Edwards) ____________ __ __ __ __ _ 2 X

Cytheretta burnsi (Ulrich and Bassler) ___ _____ X __ X _ _ *X

porcella (Ulrich and Bassler) _________________ X X X X __ X

Cytheridea muelleri subsp _________________ _ _ __ X

sp. A ____________________________________ ? X

sp. B ____________________________________ __ __ X

Cytheromorpha curta (Edwards) ______ _ __ _ _ _ 2 X X X

warneri (Howe and Spurgeon) _______ ____ _ X X X X _ __ X

Cytheropteron subreticulatum van den Bold _____________ X X X

Cytherura elongata (Edwards) __ _ _ _ X X X X X X

forulata (Edwards) ___________________-_____ X X X X X X X

cf. C. gibba (Miiller) __________________________ __ __ __ __ __ *X X

Echinocythereis clarlcana (Ulrich and Bassler) _________ X X X

Eucythere triangulata (Puri) _____________________ __ __ X __ _ _ X

Haplocytheridea bradyi (Stephenson) ______________ __ ______ X X X

setipunctata (Brady) ______ __ _ X X X X __ X X

Hemicytherura howei (Puri) ____________________ X X X X X X

Jonesial sp _______________________________ __ __ X

Leptocythere paracastanea Swain ___________________ __ __ X

Loxoconcha purisubrhomboidea (Edwards) ______________ ? X X X X X X

reticularis (Edwards) _________________________ X X X X X X X

wilberti (Puri) ______________________________ X X __ X X

sp ___________.._ __________ _ X __ X __ a X

Muellerina micula (Ulrich and Bassler) ________________ X X X X X X X

Murrayina macleani, n. sp _________________________ __ __ X

Neocaudites triplistriata (Edwards) _______________ __ _ __ _ 2 X

Neocytherideis sp ________________________ __ __ X

Orionina vaughani (Ulrich and Bassler) ______________ 4 X X X X X X ?

Paracytheridea altila (Edwards) _____________________ ? X X _ XXX

mucra (Edwards) ____________________________ _ __ __ __ X 'X

Paradoxostoma robustum (Puri) ____________________ X X X X

Pontocythere (H.) agricola duopunctata, n. subsp _________ ? X X X X J X

(H.) ashermani (Ulrich and Bassler) _______________ X X X X X X ?

(H.) cf. P. (H.) rugipustulosa (Edwards) ____________ _ _ _ __ 2 X

Prodictyocythere trapezoidalis. n. gen., n. sp _____________ __ X X

Propontocypris howei (Puri) ________________________ _ XX

Proteoconcha gigantica (Edwards) ________________ _ __ _ _ 2 X X

multipunctata (Edwards) _______________________ _ _ __ _ 2 X X

Protocytheretta sahnii (Puri) ________________________ __ _ _ XX _ X

Pterygocythereis americana (Ulrich and Bassler) __________ XXX

Puriana rugipunctata (Ulrich and Bassler) _____________ _ X X X X X X

mesacostalis (Edwards) ________________________ _ _ X __ X X X

Radimella confragosa (Edwards) __________________ _ ? ? X X X X

Shattuckocythere shattucki (Ulrich and Bassler) __________ X _- X __ __ ?

similis (Malkin) ____________________________ ,_ __ _ x __ J X

yorktownensis (Malkin) ________________________ _ X X X X X

Thaerocythere schmidtae (Malkin) ____________________ X X X __ 'X

sp __________ __ __ x __ __ 'X II

Xestoleberis cf. X. aurantia (Baird) ________________ __ __ _ __ __ *x X

Xestoleberisl ventrostriata (Swain) ________________ __ __ __ __ 2 x

'Beds of Pliocene (?) age at Mount Gould Landing and Colerain Landing localities, Bertie County, N.C.

2 Species obtained from the Duplin Marl in the present collection.

3 Occurrence of Cletocythereis mundorffi subsp.

4 Previously recorded from pre-upper Miocene of niOrthera South America
OSTRACODA OF THE YORKTOWN FORMATION

MIDDLE YORKTOWN

The localities designated by Gibson as representing the middle Yorktown Formation and which 

yielded Ostracoda are as follows:

1. (Gibson's samples C-l and C-2.) A bluff on the 

south bank of Nansemond River 0.5 mile northeast of Highway 258 bridge in the northern 

part of Suffolk, Nansemond County, Virginia; 

the lowermost 2 feet are composed of bluish 

clayey sand, only sparingly fossiliferous; the 

upper 9 feet are yellowish clayey sand, fairly 

fossiliferous throughout but with several concentrated shell bands; sample C-l is from 1 

foot above the base of the section in the lower 

unit, and sample C-2 is from 5 feet above the 

base of the upper unit.

2. (Gibson's samples D-l and D-2.) A bluff on the 

western bank of Nansemond River 1.5 miles 

northeast of Highway 258 bridge in the northern part of Suffolk, Nansemond County, Va.; 

13 feet of yellow clayey sand are exposed; the 

lowermost 2 feet are only sparingly fossiliferous, and the upper 11 feet are quite fossiliferous ; sample D-l is from 7 feet above the base, 

and sample D-2 is from a Mulinia congesta bed 

8 feet above the base.

3. (Gibson's samples K-l to K-4.) Along bank of 

Lieutenant's Run on the southwest side of 

Petersburg, Dinwiddie County, Va., 0.5 of a 

mile east of Atlantic Coast Line Railroad; 

about 15 feet of section are exposed in creek 

bank; the lowest 4 feet are composed of bluish 

sand and contain a great number of fossils, 

mainly Bivalvia; above the lower unit the beds 

gradually become more clayey and less fossiliferous toward the top; uppermost 3 feet are 

very clayey and barren of fossils; sample K-l 

is from 2 feet up in the section; sample K-2 is 

from 6 feet above the base; K-3 is from 10 

feet above the base, and K-4 is in the barren 

unit 13 feet above the base.

4. (Gibson's samples P-l and P-3.) Bluff 0.5 of a 

mile north of Fergusson's wharf on the west 

bank of James River, east of Rushmere, Isle of 

Wight County, Va.

5. (Gibson's samples R-l to R-4.) Bluff at Morgart's Beach on the south bank of James River, 

5 miles north of Smithfield, Isle of Wight 

County, Va.

6. (Gibson's samples S-l to S-5.) South bank of 

Yorktown River about 1 mile downstream 

from Yorktown at base of Moore House Bluff, 

James County, Va.

The ostracode species that are restricted to the 

middle Yorktown as designated by Gibson and represented in the present collection and that are not 

definitely known to occur in older to younger units 

in previously described collections are: Cytheridea 

sp. B; Cytheridea muelleri (Miinster, 1830) subsp.; 

Cletocythereis mundorffi (Swain, 1952) subsp.; 

Murrayina macleani, n. sp.; and Neocytherideis sp.

Several species of this or previously recorded collections have been found in the middle Yorktown or 

younger deposits but not in the pre-middle Yorktown: Bairdoppilata triangulata Edwards, 1944; 

Lepjocythere paracastanea Swain, 1955; Loxoconcha wilberti Puri, 1954; Costa barclayi (McLean, 

1957) ; Campylocythere laeva posteropunctata Edwards, 1944; Acuticythereis laevissima punctata 

Edwards, 1944; Eucythere triangulata Puri, 1954; 

Puriana mesacostalis (Edwards, 1944) ; and Thaerocythere sp.

A few species range from older deposits into the 

middle Yorktown but have not been found in younger beds: Prodictyocythere trapezoidalis, n. gen., n. 

sp.; Campylocythere sp.; Cytheretta burnsi (Ulrich 

and Bassler, 1904) ; Cytheropteron subreticulatum 

van den Bold, 1946; and Pterygocythereis americana 

(Ulrich and Bassler, 1904).

LOWER YORKTOWN

The samples designated as representative of the 

lower part of the Yorktown Formation in T. G. 

Gibson's collection are as follows:

1. (Gibson's samples A-l to A-6.) Maddry's Bluff 

on the south bank of Meherrin River, 1 mile 

downstream from the Highway 258 bridge 

over the river, 1 mile northeast of Murfreesboro, Hertford County, N.C.

2. (Gibson's samples B-l, B-2.) Bluff on the south 

bank of Meherrin River, 2 miles upstream 

from Highway 258 bridge over the river, 1 

mile northeast of Murfreesboro, Hertford 

County, N.C., lower unit is composed of 3.5 

feet of bluish clayey sand with many large 

bivalves and an upper unit of 4 feet of sandy 

clay; sample B-l is from 3 feet up in the 

lower unit, and sample B-2 is from 2 feet up 

in the upper unit.

3. Bluff on the south side of Meherrin River, 7.5 

miles upstream from the Seaboard Air Line 

Railroad Bridge between Boykins, Va., and 

Severn, Northampton County, N.C.; 4 feet of 

bluish clayey sand are exposed at the base of 

the bluff, and are richly fossiliferous, es-
UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

pecially with Pecten and Glycymeris; sampled 2 feet above the base of section.

4. One mile upstream from the bridge mentioned 

in the preceding paragraph, sampled in the 

same unit, 3 feet from the base of the section.

5. (Gibson's samples L-l, L-2.) Just below the 

outlet of City Pond in a small stream cut on 

the southwest side of Petersburg, Dinwiddie 

County, Va.; 20 feet of beds are exposed with 

the lower 15 feet being bluish-gray sandy clay 

which contains only a few scattered fossils 

and the upper 5 feet being bluish clayey sand 

with a great number of Mercenaria and Turritella; sample L-l was taken 2 feet from the 

top of the lower unit and sample L-2 from 6 

inches above the base of the upper unit.

6. (Gibson's samples M-l to M-3.) Bluff 200 yards 

upstream from the mouth of Sunken Marsh 

Creek on the south bank of James River, Surry County, Va.; may include upper St. Marys 

Formation in lower part of exposure.

7. (Gibson's samples N-l, N-2.) Bluff at Mount 

Pleasant Plantation on south bank of James 

River, Surry County, Va.; section is composed 

of a lower 15-foot unit of bluish-gray clayey 

sand with scattered fossils and an upper 20- 

foot unit of yellow sand with extremely abundant fossils; sample N-l is from 6 feet up in 

the lower unit and N-2 is from 10 feet up in 

the upper unit; may include upper St. Marys 

Formation in lower part of exposure.

8. (Gibson's sample T-1.) Small bluff 0.5 of a mile 

downstream from the Fishery Building at 

Urbanna, Middlesex County, Va.; approximately 2 feet of very coarse yellow sand are 

exposed at the base of the bluff; megafossils 

are abundant, with Pecten and Chama being 

the most common genera; the sample was 

taken 1 foot above the beach.

9. (Gibson's sample U-l.) Small bluff 0.5 of a mile 

upstream from Punchbowl on the south shore 

of Rappahannock River, Essex County, Va.; 

1.5 feet of coarse bluish sand is exposed at 

the base of the bluff, with the sample being 

taken 1 foot above the beach; megafossils are 

abundant with Pecten, Vermetus, and Ostrea 

the most common; possibly represents upper 

part of St. Marys Formation rather than 

lower Yorktown.

10. (Gibson's sample V-l.) Small bluff 1.5 miles 

below Bowlers wharf on the south bank of 

Rappahannock River, Essex County, Va.; 6 

feet of bluish clay are exposed, with megafossils fairly abundant, particularly Mulinia, 

Andara, and Mercenaria; sample V-l was 

taken 3 feet from the base of the section; 

possibly represents upper part of St. Marys 

Formation, rather than lower Yorktown. 

11. (Gibson's sample Z.) Cut on the east side of 

U.S. Highway 301, about 200 yards south of 

the bridge over Chickahominy River, Hanover County, Va.; about 10 feet of bluish 

clayey sand are exposed, with the lower half 

containing mostly Turritella, together with 

Mulinia and Dentalium, and the upper half 

being barren of megafauna; sample Z was 

taken 2 feet above the base of the section.

The only species of Ostracoda of the present or previously recorded collections that are 

restricted to the lower Yorktown or possibly 

to the uppermost St. Marys in Essex, Hanover, and Surry Counties, Va. are: Aglaiocypris sp. and Cytheridea sp. A. The latter 

may also occur in Oligocene deposits in the 

Hatteras Light 1, Dare County, N.C., 1,620- 

1,630 feet (Swain, 1952, p. 20) where it was 

recorded as Haplocytheridea sp. aff. H. israelskyi Stephenson, 1944.

The following Ostracoda were recorded by 

Ulrich and Bassler (1904) from the Chesapeake Group (mainly Yorktown Formation) 

at Yorktown and James River, Va.: Cythere 

burnsi Ulrich and Bassler, 1904; Cythere 

clarkana Ulrich and Bassler, 1904; C. clarkana miniscula Ulrich and Bassler, 1904; 

Cythere martini Ulrich and Bassler, 1904; 

Cythere micula Ulrich and Bassler, 1904; 

Cythere planibasilis Ulrich and Bassler, 1904; 

Cythere plebeia Ulrich and Bassler, 1904; 

Cythere porcella Ulrich and Bassler, 1904; 

Cythere rugipunctata Ulrich and Bassler, 

1904 (types from James River) ; Cythere tuomeyi Ulrich and Bassler, 1904; Cythere 

vaughani Ulrich and Bassler, 1904; (types 

from James River, Va.) ; Cythereis alaris 

Ulrich and Bassler, 1904 (types from James 

River) ; Cythereis cornuta americana Ulrich 

and Bassler, 1904; Cytherideis ashermani 

Ulrich and Bassler, 1904; and Cytheropteron 

nodosum Ulrich and Bassler, 1904; (types 

from James River, Va.).

Of these species (with modern generic assignments given), Cytheretta burnsi (Ulrich 

and Bassler, 1904), Echinocythereisl clarkana (Ulrich and Bassler, 1904), Actinocythereis exanthemata (Ulrich and Bassler,
OSTRACODA OF THE YORKTOWN FORMATION

1904), Muellerina micula, (Ulrich and Bassler, 1904), Cytheretta porcella (Ulrich and 

Bassler, 1904), Puriana rugipunctata (Ulrich and Bassler, 1904), Orionina vaughani 

(Ulrich and Bassler, 1904), Pterygocythereis 

americana (Ulrich and Bassler, 1904), Pontocythere ashermani (Ulrich and Bassler, 

1904), and Paracytheridea altila Edwards, 

1904 ( = Cytheropteronnodosum) Ulrich and 

Bassler, 1904 occur in the Yorktown Formation in the present collections. Henryhowella 

evax (Ulrich and Bassler, 1904), Echinocythereisl planibasilis (Ulrich and Bassler, 

1904), and Leguminocytherist tuomeyi (Ulrich and Bassler, 1904), however, in the present collections have been found only in preYorktown Miocene deposits. Furthermore, 

among the species that she obtained from the 

Yorktown Formation, Malkin (1953) did not 

record H. evax.

Malkin recorded 29 species of Ostracoda 

from the Yorktown Formation near Yorktown and Grove, Va. Twenty-three of these 

were found in the present collections from 

the Yorktown; the other six species are: 

Cushmanidea echolsae (Malkin, 1953) ; Pontocythere subaequalis ulrichi (Howe and 

Johnson, 1935) ; Clithrocytheridea virginiensis (Malkin, 1953) ; Anomocytheridea floridana (Howe and Hough, 1935) ; Shattuckocythere shattucki (Malkin, 1953) subsp.; 

and Cytherura wardensis Howe and Brown, 

1935. Malkin also recorded Bairdia spp. from 

the Yorktown.

McLean (1957) obtained species of Ostracoda from the Yorktown Formation of the 

York-James Peninsula, Va. Eighteen of the 

species occur in the present collections from 

the Yorktown. The other six species found by 

McLean are: Paracypris choctawhatcheensis 

Puri, 1954; Cytheropteron talquinensis Puri, 

1954; Cytherura lumbertonensis Edwards, 

1944; Clithrocytheridea virginiensis Malkin, 

1953; Eucythere sp.; and Cushmanidea. echolsae (Malkin, 1953). Among the recorded 

Yorktown species and subspecies of Ulrich 

and Bassler (1904), Cythere clarkana miniscula Ulrich and Bassler, 1904 is considered 

by the writer to represent immature molts 

based on a study of cotypes 35414 from the 

Calvert Formation at Plum Point, Md., 

housed in the National Museum. They are 

apparently molts of Echinocythereist clarkana (Ulrich and Bassler, 1904). "Cythere 

martini" Ulrich and Bassler, 1904 as used by 

authors in recent years, as discussed by Hazel 

(1967) is for the most part, not congeneric 

with the types of martini but belong to Muellerina Bassiouni (1965) or a related genus of 

the Hemicytheridae rather than to the 

Trachyleberidae to which martini should be 

referred. The "Cythere martini" of the Yorktown Formation should, the present writer 

believes, be referred to Muellerina micula 

(Ulrich and Bassler, 1904), rather than to 

the species "Cythere lienenklausi" Ulrich and 

Bassler, 1904, as recommended by Hazel 

(1967). The type of C. lienenklausi in the 

U.S. National Museum is too badly broken 

for one to be sure of its characteristics and 

the reference of Recent North Atlantic specimens to that species (Hazel, 1967) is doubtful.

Cythere plebeia (Ulrich and Bassler, 1904) 

of the Yorktown is here included with Cytheretta porcella (Ulrich and Bassler, 1904) 

as a junior objective synonym. Cythereis 

alaris (Ulrich and Bassler, 1904) of the 

Yorktown is an immature molt of Pterygocythereis americana (Ulrich and Bassler, 

1904) (Pooser, 1965).

The total number of ostracode species recorded herein from the Yorktown Formation 

is 75 of which 63 were found in the present 

collections and 12 others were obtained by 

Malkin (1953) and McLean (1957). Hazel 

(1971) states that 230 species of Ostracoda 

occur in the Yorktown Formation as delineated by him.

An important group of species in the present collection deserve mention as not being 

known to occur in pre-Yorktown or preDuplin Miocene deposits in the area 

studied ; these are: Aglaiocypris sp.; 

Aurila conradi (Howe and McGuirt, 1935) ; 

Bairdoppilata triangulata Edwards, 1944; 

Proteoconcha gigantica (Edwards, 1944) ; 

Campylocythere laeva Edwards, 1944; Campylocythere laeva posteropunctata Edwards, 

1944; Acuticythereis laevissima punctata 

(Edwards, 1944) ; Proteoconcha multipunctata (Edwards, 1944) ; Campylocythere sp.; 

Caudites sp.; Caudites sellardsi (Howe and 

Neill, 1935) ; Caudites choctawhatcheensis 

Puri, 1954; Costa barclayi (McLean, 1957) ; 

Cytherelloidea umbonata Edwards, 1944; Cytheridea sp. B.; Cytheridea muelleri (Mtin-
UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

ster, 1830) subsp.; Cytheromorpha curta 

Edwards, 1944; Cytherura elongata Edwards, 

1944; Eucythere triangulata Puri, 1954; Haplocytheridea bradyi (Stephenson, 1938) ; Cletocythereis mundorffi (Swain, 1952) ; Cletocythereis mundorffi subsp.; Jonesial sp.; 

Loxoconcha sp.; L. wilberti Puri, 1954; Murrayina macleani, n. sp.; Radimella confragosa 

(Edwards, 1944) ; Neocaudites triplistriatus 

(Edwards, 1944) ; Neocytherideis sp; Paracytheridea mucra Edwards, 1944; Pontocythere (Hiding sina) agricola (Howe and 

Hough, 1935) ; Pontocy'there (H.) agricola 

duopunctata, n. subsp.; Prodictyocythere 

trapezoidalis, n. gen., n. sp.; Propontocypris 

howei (Puri, 1954) ; Protocytheretta sahnii 

Puri, 1952; Puriana rugipunctata (Ulrich 

and Bassler, 1904) ; Puriana mesacostalis 

(Edwards, 1944) ; Shattuckocythere shattucki (Ulrich and Bassler) ; Shattuckocythere similis (Malkin, 1953) ; Shattuckocythere yorktownensis (Malkin, 1953) ; Thaerocythere schmidtae (Malkin, 1953) ; Thaerocythere sp.; and Xestoleberisl ventrostriata 

Swain, 1956.

OSTRACODA OF THE DUPLIN MARL

The ostracode species obtained from the Duplin 

Marl in the collections studied are listed in table 1. 

The Duplin localities sampled by Thomas Gibson are 

as follows:

1. Marl pit on the Barwick Farm, southwest of 

Kenansville, Duplin County, N.C.; 4 feet of 

yellow clayey sand are exposed, the sample 

being taken 3 feet above the base of the section ; megafossils are abundant at this locality.

2. Natural Well, 2 miles west of Magnolia, Duplin 

County, N.C.; 4 feet of bluish clayey sand are 

exposed; the sample was taken 3 feet above the 

base of the section; megafossils are fairly 

abundant.

3. A small bluff on the northern bank of Lumber 

River about 1.5 miles southeast of Lumberton, 

Robeson County, N.C.; 100 yards upstream 

from the point where Highway 74 crosses the 

river; 10 feet of yellow clayey sand are exposed; megafossils are abundant, with Glycymeris being the most numerous form; sample 

was taken 8 feet above the base of the section.

4. A small marl pit on the Duvar Farm 1 mile east 

of Tar Heel, Robeson County, N.C.; 3 feet of 

yellow clayey sand are exposed, and the sample was taken in the upper foot; megafossils 

are fairly abundant, with Mulinia being the 

most numerous form.

5. A small roadcut on the 0. H. Alien farm, 0.5 of a 

mile east of Tar Heel, Robeson County, N.C.; 

4 feet of yellow coarse sand are exposed, with 

the sample being taken 3 feet above the base 

of the section. Glycymeris is the most abundant megafossil.

6. Walkers Bluff on the southern bank of Cape Fear 

River, 9 miles below Elizabethtown, Bladen 

County, N.C.; 5 feet of beds are exposed; the 

lowermost 2 feet are composed of yellow sand 

with much shell hash; sample 6-1 is from 1 

foot above base of section, and 6-2 is from 4 

feet above the base.

The Duplin Ostracoda are for the most part represented also in the Yorktown Formation, but the following Duplin species were not found in the Yorktown in this collection: Haplocytheridea bradyi 

(Stephenson, 1938), Proteoconcha gigantica (Edwards, 1944), Caudites choctaivhatcheensis (Puri, 

1954), C. sellardsi (Howe and Neill, 1935), C. sp. 

Cushmanideal agricola (Howe and Hough, 1935), 

Proteoconcha multipunctata (Edwards, 1944), Cytherelloidea umbonata (Edwards, 1944), Cytheromorpha curta Edwards, 1944, Neocaudites triplistriatus (Edwards, 1944), Paracytheridea mucra 

Edwards, 1944, and Xestoleberisl ventrostriata 

Swain, 1952.

Edwards (1944) described 35 species and four 

subspecies from the Duplin Marl of North Carolina 

of which 29 species and three subspecies were new. 

The previously described species and subspecies are 

Anomocytheridea floridana Howe and Hough, 1935, 

Pontocythere ashermani Ulrich and Bassler, 1904, 

Aurila conradi (Howe and McGuirt, 1935), Actinocythereis exanthemata gomillionensis (Howe and 

Ellis, 1935), Orionina vaughani (Ulrich and Bassler, 1904), Puriana rugipunctata (Ulrich and Bassler, 1904), and Cytherura ivardensis Howe and 

Brown, 1935. Subsequently, most of the Duplin species have been found in the Yorktown, except those 

listed in the preceding paragraph.

Several species recorded from the Yorktown have 

not been found in the Duplin. Prodictyocythere 

trapezoidalis n. gen., n. sp.; Aglaiocypris sp.; Cushmanidea ulrichi (Howe and Johnson, 1935) ; C. 

fabula (Howe and Dohm, 1935) ; Campylocythere 

sp.; Cytheretta burnsi (Ulrich and Bassler, 1904) ; 

Cytheretta porcella (Ulrich and Bassler, 1904) ; Cytheridea sp. B.; C. muelleri (Minister, 1830) subsp.; 

C. sp. A; Leptocythere paracastanea Swain, 1955;
OSTRACODA DISTRIBUTION BASED ON COLLECTIONS STUDIED HEREIN

Cytheropteron subreticulatum van den Bold, 1946; 

Loxoconcha sp.; Shattuckocythere similis (Malkin, 

1953); Luvulal sp.; Murrayina macleani, n. sp.; 

Neocytherideis sp.; Paradoxostoma robusta Puri, 

1954; Pontocythere agricola duopunctata, n. subsp.; 

Pterygocythereis americana (Ulrich and Bassler, 

1904) ; Thaerocythere schmidtae (Malkin, 1953) ; 

and T. sp.

Pooser (1965), however, obtained Pterygocythereis americana from the Duplin Marl of South Carolina. He also recorded five other species from the 

Duplin, including the following forms that were not 

recorded from the Duplin by Edwards (1944) or in 

the present paper: Munseyella subminuta (Puri, 

1954) ; Cytherura johnsoni Mincher, 1941; Cytherelloidea leonensis Howe; Haplocytheridea bassleri 

Stephenson, 1943; and Protocytheretta karlana 

(Howe and Pyeatt, 1935).

UPPER MIOCENE OSTRACODA FROM WELLS 

IN THE ATLANTIC COASTAL PLAIN

The presumed upper Miocene Ostracoda from several wells in the Atlantic Coastal Plain of eastern 

North Carolina recorded by Swain (1952) represented 42 species. Of those species only Basslerites 

cf. B. miocenicus Howe, 1935, is not represented in 

the surface upper Miocene deposits discussed above.

In a discussion of subsurface stratigraphy of the 

North Carolina coastal plain, Brown (1958) listed 

25 species of upper Miocene Ostracoda all but one of 

which had been found previously in outcrops or wells 

in the upper Miocene. The one species is Henryhowella evax (Ulrich and Bassler, 1904) which the 

present writer considers as being restricted to preupper Miocene deposits in the Atlantic coastal area.

Hall (1965) has recently studied reworked upper 

Miocene Ostracoda from cores in the Pleistocene and 

Holocene on Sapelo Island, Ga. Twenty-one of the 

species he identified were considered to be restricted 

to the upper Miocene and younger. The ranges of 

some of the species cited by Hall differ from those 

found by the present writer in the coastal plain 

farther north, and additional study in the intervening area is necessary to verify the true ranges of 

these forms.

SUMMARY OF OSTRACODA DISTRIBUTION

IN UPPER MIOCENE AND PLIOCENE

OF ATLANTIC COASTAL PLAIN BASED ON

COLLECTIONS STUDIED HEREIN

Most of the abundant upper Miocene ostracode 

species of the Atlantic Coastal Plain also range into

younger deposits. The Pliocene Waccamaw Formation of North and South Carolina contains many 

ostracode species in common with the Duplin and 

Yorktown Formations (Swain, 1968). Some geologists have suggested that the Duplin and Yorktown 

may be in part Pliocene based on the modern aspect 

of their faunas compared with those of the underlying St. Marys, Choptank, and Calvert Formations 

(Hazel, 1971). The Pleistocene of the Atlantic 

coastal region is relatively scarce in Ostracoda, but 

the Holocene contains a relatively large fauna on the 

continental shelf and in some of the more southerly 

bays.

As stated above, about 47 species of subspecies of 

ostracodes that occur in the Yorktown or Duplin 

Formations or in younger deposits are not known to 

be present in pre-upper Miocene rocks. The upper 

Miocene and Pliocene of the area studied are represented by the Aurila conradi-Thaerocythere schmidtae assemblage. Radimella confragosa (Edwards, 

1944) is abundant in the upper Miocene Duplin Marl 

and Pliocene Waccamaw Formation of southern 

North Carolina and northern South Carolina, but 

is uncommon in the Yorktown Formation. It is 

selected to represent the Radimella confragosa subassemblage of the A. conradi-T. schmidtae assemblage that characterizes the uppermost Miocene and 

Pliocene in southern North Carolina and northern 

South Carolina. Van den Bold (1966) also recognized the stratigraphic usefulness of R. confragosa 

in the uppermost Miocene. Thaerocythere schmidtae 

(Malkin, 1953) on the other hand is rare or absent 

in the Duplin Marl and Waccamaw Formation, but 

is relatively abundant in the Yorktown Formation 

of northern North Carolina, Virginia, and Maryland 

(that is, the southern Virginian province of Dana, 

1853). Thaerocythere schmidtae thus characterizes 

the upper Miocene of the northern part of the area 

discussed, that is northern North Carolina, Virginia, 

and southernmost Maryland. This presumably represents a cooler water subassemblage of the upper 

Miocene than does R. confragosa subassemblage. At 

present Thaerocythere (that is, T. cremdata (Sars, 

1866)) is found in the North Atlantic region (Hazel, 

1967) while R. confragosa is living in the Gulf of 

Mexico (Puri, 1960). The upper Miocene ostracodes 

are marine and generally represent an open shelf 

sublittoral environment. Some of the forms, such as 

Cytheromorpha warneri Howe and Spurgeon, 1935, 

and C. curta Edwards, 1944, and Leptocythere paracastanea Swain, 1955, may indicate local lagoonal or 

estuarine conditions.

The middle Miocene, underlying the Yorktown
10 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

and Duplin Formations in the area studied is represented by an assemblage of Murrayina gunteri 

(Howe and Chambers, 1935) ; M. howei Puri, 1954; 

Cytheretta spencerensis Smith, 1941; C. inaequivalvis (Ulrich and Bassler, 1904) and other species. 

The middle Miocene assemblage consists of marine 

species that mostly suggest an open shelf sublittoral 

environment.

Valentine (1971) has recently recorded an upper 

Pleistocene (Sangamon) ostracode assemblage of 

82 species from the Norfolk Formation as used by 

Oaks and Coch (1963) of southeastern Virginia. He 

finds that 70 of the species are still living. When the 

Norfolk assemblage is compared with present day 

ostracode assemblages from the continental shelf, 

none of the modern assemblages is comparable to 

that of the Norfolk Formation. The latter contains 

some species that today are found only north or 

south of Cape Hatteras. When compared to the distribution of modern forms it appears that the late 

Pleistocene assemblage lived in waters that were 

warmer and more equable than now prevail off 

southeastern Virginia.

The living ostracodes of bays and estuaries in 

North Carolina and Georgia include upper Miocene 

species that seem to represent a warm-water assemblage of Floridian and Carolinian origins (Darby, 

1965; Grossman and Benson, 1967). The living 

ostracodes of Chesapeake Bay, however, include species that have not been found in the fossil assemblages, that is, Cytheridea papillosa Bosquet, 1852 

(auct.) ; Heterocythereis albomaculata (Baird, 

1838), (auct.) ; and Hemicythere strandentia Tressler and Smith, 1948, (Tressler and Smith, 1948). 

The ostracodes recorded by Hulings (1966) from the 

Atlantic continental shelf off Virginia also are mainly represented by North Atlantic forms. In a recent 

study of western Atlantic ostracodes, Hazel (1970) 

found distinctive differences in the ostracode assemblages in the region from Nova Scotia to Long 

Island. About 50 percent of the species are of European occurrence, but less than 25 percent of species 

from the Virginian mild-temperate province are 

known to have reached European waters. The comparative sparsity of amphiatlantic species passing 

Cape Cod from the north as compared to endemic 

thermophilic species passing the Cape from the 

south is interpreted by Hazel as caused by seasonal 

isothermal variations.

Hazel (1971) has proposed a zonation of the Yorktown Formation of Virginia and North Carolina 

based on ostracodes, and utilizing binary similarity 

coefficients and cluster analysis to establish his

zones. Without going into a discussion of the method 

itself, comments herein are restricted to the data 

used to establish the zonation.

A critical locality in Hazel's study is that of the 

Texas Gulf Sulphur Co. open-pit phosphate mine at 

the mouth of Lees Creek near Aurora, N.C. Hazel 

states (1971, p. 7) that the lowest of his three ostracode zones, the Pterygocythereis inexpectata Zone, 

occupies the lower 10 feet of sands, phosphate pebbles, and quartz pebbles overlying the phosphatic 

sands and diatomaceous clays of the middle Miocene 

Pungo River Formation. The upper Pungo River 

here contains an abundant microfauna of middle 

Miocene ostracodes in collections obtained by the 

writer and by P. M. Brown and James Miller. In 

collections of the lower Yorktown, in which reworked phosphatic pebbles and nodules are common, 

there are also abundant middle Miocene ostracodes, 

which the writer also interprets as reworked, together with Yorktown species of ostracodes. The 

middle Miocene forms include Murrayina gunteri 

(Howe and Chambers, 1935) ; M. howei Puri, 1954; 

Cytheretta spencerensis Smith, 1941 and other 

forms. The upper Miocene species represented in the 

lower part of the Yorktown here include Aurila conradi (Howe and McGuirt, 1935) ; and Radimella 

confragosa (Edwards, 1944). The presence of R. 

confragosa here suggests that the oldest Yorktown 

beds in the Lees Creek pit may represent middle or 

upper parts of the formation in the other sections 

studied, as this species is most common in upper 

Yorktown-age deposits elsewhere. Thus the numerous species which Hazel (1971, table 1) records from 

the Yorktown Formation in the Lees Creek pit (his 

samples 2-5) are thought by the present writer to 

include many forms that have been reworked from 

the middle Miocene. Because he lists a great many of 

his species with open nomenclature, it is not possible 

to decide which ones are of middle Miocene affinity. 

In the present writer's collection, the Pungo River 

species are mainly those that occur in the Calvert, 

Choptank, and St. Marys Formation of the Chesapeake Bay region. Although many of the forms 

range into the overlying Yorktown Formation, certain ones, including those mentioned above do not 

occur in the Yorktown, and several of the Yorktown 

species do not range down into the pre-Yorktown 

deposits.

One of the species used by Hazel in establishing 

his second Yorktown zone is Orionina vaughani, a 

form that the present writer considers to be longranging in the lower, middle, and upper Miocene and 

to be unsuitable to serve as a zone indicator within
SYSTEMATIC DESCRIPTIONS 11

the Miocene. Similarly, the species indicator of his 

lower zone, Pterygocythereis inexpectata is recorded 

as living in the Atlantic Ocean and does not appear 

to be useful to establish an early upper Miocene 

zone. The records of this species in the Lees Creek 

pit, the writer furthermore believes, may be based 

on specimens reworked from the middle Miocene.

As an example of the problems that may arise 

from local reworking of older microfaunas into 

younger beds, one may refer to the recognition by 

Hazel himself (1971, p. 7) that such reworking at 

Yadkin, Va. has brought together in the same bed 

species of both his Orionina vaughani Zone and his 

overlying Puriana mesacostalis Zone.

Puriana mesacostalis (Edwards, 1944) is cited by 

Hazel as tentatively indicative of a Pliocene age for 

the upper part of the Yorktown Formation. Two of 

the localities he cited as representative of the Puriana mesacostalis Zone of the Yorktown Formation 

are: 0.5 of a mile below Mount Gould Landing, Bertie County, N.C. and 150 yards south of Colerain 

Landing, Bertie County, N.C. The outcrops at both 

these localities consist of buff, dark-brown shell hash 

of different lithologic characteristics than the Yorktown Formation and are post-Yorktown in stratigraphic position as well as in age. Finally, P. mesacostalis was described from the upper Miocene Duplin Marl and cannot, by itself, be indicative of Pliocene age of the containing deposits. No definitive 

evidence has yet been cited for the post-Miocene age 

of the Duplin, but it does contain many upper Miocene fossils.

SYSTEMATIC DESCRIPTIONS

Family PARACYPRIDIDAE Sars, 1923 

Genus AGLAIOCYPRIS Sylvester-Bradley, 1947

Aglaia Brady, 1868, Les Fonds de la Mer, v. 1, (1967-71), 

part I, XVIII, p. 90 [non Renier, 1804; non Swainson, 

1927].

Aglaiocypris Sylvester-Bradley, 1947, Annals Mag. Nat. History, ser. 11, v. 13, p. 197.

Aglaja Schneider, 1949, Microfauna USSR v. 2, All-Union 

Petrol. Sci-Res. Geol. Expl. Inst., Leningr. (VNIGRI), 

Trans. v. 30, p. 117. (Misspelling of Aglaia.)

See Moore and others (1961, p. 245) for diagnosis 

of the shell of the genus. Type species, Aglaia pulchella Brady, 1868. Geologic range, Miocene to 

Holocene.

Aglaiocypris sp.

Plate 1, figure 2

Shell elongate-subelliptical in side view, highest 

medially; dorsal margin gently convex; ventral margin nearly straight to slightly convex; terminal margins nearly equally rounded, the anterior slightly the 

narrower. Valves moderately convex, the left slightly the larger; surface smooth. Hinge of right valve 

consists of narrowed valve edge. Inner lamellae of 

moderate width and with broad vestibules terminally; radial canals few or absent; adductor muscle 

scar a median compact group of four or five spots.

Length of figured right valve specimen 0.88 mm., 

height 0.38 mm., convexity 0.18 mm.

Relationships. The elongate-subelliptical outline, 

hingement and other internal shell structures relate 

this species to Aglaiocypris. The present species is 

more elongate than living form A. pulchella (Brady, 

1868), the type species, and has a less convex dorsum than A. complanata Brady and Robertson, both 

from the North Atlantic and a less concave venter 

than A. virgenensis Swain, 1967 from the Gulf of 

California.

Occurrence. The species is rare in the lower 

part of the Yorktown Formation, locality U-l, Essex 

County, Va.

Number of specimens studied. Two.

Ecology. Only a few species are associated with 

A. sp. and they suggest a sublittoral marine 

environment.

Zoogeographic derivation. Aglaiocypris is of 

North Atlantic origin and the present species possibly originated in the western North Atlantic region 

off eastern North America, in the Virginian, Nova 

Scotian, or Arctic Faunal Provinces.

Figured specimen. USNM 179512.

Family PONTOCYPRIDIDAE Muller, 1894 

Genus PROPONTOCYPRIS Sylvester-Bradley, 1947

Propontocypris Sylvester-Bradley, 1947, Annals Mag. Nat. 

History ser. 11, v. 13, p. 193.

The shell of the genus was described by SylvesterBradley (1947) and was summarized by Moore and 

others (1961, p. 247). Type species, Pontocypris 

trigonella Sars, 1866. Geologic range, Miocene to 

Holocene.

Propontocypris howei (Puri)

Plate 1, figures 3, 15 

Bythocypris howei Puri, 1954, Florida Geol. Survey Bull.

36, p. 226, pi. 1, figs. 14-16, text figs. 2e-g. 

Propontocypris howei (Puri). Hulings, 1966, Chesapeake

Sci., v. 7, p. 46, figs, la-c, 6a.

Occurrence. The species was obtained from the 

lower and middle parts of the Yorktown Formation, 

upper Miocene, in the present collection. 1 Puri (1954) 

described it from the Area, Ecphora, and Cancellaria 

facies of the Choctawhatchee Formation (of former 

usage) upper Miocene. Hulings recorded the species

1 Detailed lists of occurrences not presented herein are available in openfile reports of the Geological Survey.
12 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

living in the Atlantic Ocean off the Virginia coast, 

and by means of a study of the appendages was able 

to demonstrate a closer affiliation for Propontocypris 

Sylvester-Bradley than for Bythocypris Brady.

Number of specimens studied. Four.

Ecology. The species occupied, in Miocene time, 

an open marine shelf at neritic depths judging from 

living occurrences.

Zoogeographic derivation. This group of Ostracoda seems to have originated in the Boreal or Arctic 

Faunal Provinces of the North Atlantic area.

Figured specimen. USNM 179513.

Family BAIRDIIDAE Sars, 1888 

Genus BAIRDOPPILATA Coryell, Sample, and Jennings, 1935

Bairdoppilata Coryell, Sample, and Jennings, 1935, Am. 

Mus. Novitates, no. 777, 5 p., 4 figs.

See Moore and others (1961, p. 205) for diagnosis 

of the shell. The shell and appendages of the genus 

were discussed recently by Maddocks (1969) who 

has extended its range to the Holocene Epoch. Type 

species, B. martyni, Coryell, Sample, and Jennings 

(1935). Geologic range, Lower Cretaceous to 

Holocene.

Bairdoppilata triangulata Edwards 

Plate 1, figure 1

Bairdoppilata triangulata Edwards, 1944, Jour. Paleontology, 

v. 18, p. 507, pi. 85, figs. 5, 6; Puri, 1954, Florida Geol. 

Survey Bull. 36, p. 223, pi. 1, figs. 3, 4; text figs, la, 

b; Swain, 1968, U.S. Geol. Survey Prof. Paper 573-D, 

p. 6, pi. 1, figs. 2a, b, text figs. 2, 3; Benson and Coleman, 1963, Kansas Univ. Paleont. Contr., Arthropoda. 

Art 2, p. 20, pi. 3, figs. 1-3, text fig. 9.

Occurrence. In the Atlantic Coast region the 

species has been found from the middle Yorktown 

Formation (upper Miocene) to the Waccamaw Formation (Pliocene. Swain, 1968; Hazel, 1971), and in 

the eastern Gulf of Mexico region it occurs in the 

Choctawhatchee Formation (of former usage) ; 

middle and upper Miocene, of Florida (Puri, 1954) 

and is living off the west coast of Florida (Benson 

and Coleman, 1963).

Number of specimens. 100 +.

Ecology. The species was found by Benson and 

Coleman (1963) in water depths ranging from 19 

to 239 feet but was most common at depths greater 

than 60 feet; bottom sediments were sand-sized carbonate shell fragments; salinities ranged from 36.17 

to 39.36 parts per mil. The absence of living B. triangulata along the present Atlantic coast and shelf 

and its presence in the Waccamaw, Duplin, and middle Yorktown faunas suggest a similarity of those 

sedimentary environments with that of the present

eastern Gulf of Mexico. B. triangulata appears to 

represent neritic rather than eulittoral or bay environments judging from both its Holocene and fossil distribution.

Zoogeographic derivation. This form seems to 

have originated in the Miocene in the eastern Gulf 

of Mexico-southeastern United States area, that is in 

the Caribbean or Carolinian Faunal Provinces.

Figured specimen. USNM 179514.

Family CYTHER1DE1DAE Sars, 1925 

Subfamily CYTHERIDEINAE Sars, 1925

Genus HAPLOCYTHERIDEA Stephenson, 1936

Cytheridea (Haplocytheridea) Stephenson, 1936, Jour.

Paleontology, v. 10, p. 696. 

Leptocytheridea Stephenson, 1937, Jour. Paleontology, v. 11,

p. 157. 

IPhractocytheridea Sutton and Williams, 1939, Jour.

Paleontology, v. 13, p. 571. [Considered a valid genus

by Hazel. 1968.]

A diagnosis of the shell of the genus is provided in 

Moore and others (1967, p. 276) and the possible distinction between Haplocytheridea and Phractocytheridea is given by Hazel (1968, p. 131). The latter 

probably should be a subgenus of Haplocytheridea 

because of their similarity in hingement. Type species, Cytheridea montgomeryensis Howe and Chambers, 1935. Geologic range, Upper Cretaceous to 

Holocene.

Haplocytheridea setipunctata (Brady)

Plate 9, figure 16

Cytheridea setipunctata Brady, 1869, Les Fonds de la Mer,

v. 1, p. 124, pi. 14, figs. 15, 16. 

Cytheridea (Haplocytheridea) ponderosa Stephenson, 1938,

Jour. Paleontology, v. 12, p. 133, pi. 23, fig. 10; pi. 24,

figs. 1, 2. 

Haplocytheridea ponderosa (Stephenson). Puri, 1960, Gulf

Coast Assoc. Geol. Socs. Trans., v. 10, p. 110; Curtis,

1960, Am. Assoc. Petroleum Geologists Bull., v. 44,

pi. 23, fig. 2. 

Cyprideis ftoridana Puri, 1960, Gulf Coast Assoc. Geol.

Socs. Trans., v. 10, p. 100, pi. 2, fig. 5; text figs. 1-3

[not Cytheridea floridana Howe and Hough, 1935]. 

Haplocytheridea bassleri Stephenson. Swain, 1955 [part],

Jour Paleontology, v. 29, p. 617, pi. 59, fig. 9a [not

fig. 9b= Cyprideis ovata (Mincher), fide Sandberg,

1964]. See Sandberg, 1964, Micropaleontology, v. 10,

p. 361, for other questionable references to this species. 

Haplocytheridea gigantea Benson and Coleman, 1963, Kansas

Univ. Paleont. Contr., Arthropoda, Art. 2, pi. 27, pi. 3,

figs. 10-14; text fig. 14. 

ICytheridea puncticillata Brady. Tressler and Smith, 1948,

[part], Chesapeake Biol. Lab. pub., v. 71, pi. 1, fig. 2

[fide Sandberg, 1964]. 

Haplocytheridea setipunctata (Brady). Sandberg, 1964,

Micropaleontology, v. 10, p. 361; Sandberg, 1965, Pub.

Staz. Zool., Napoli, v. 33, supp., p. 508, pi. 3, fig. 12,

Hulings and Puri, 1965, Pub. Staz. Zool., Napoli, v. 33,
SYSTEMATIC DESCRIPTIONS 13

supp., p. 329, fig. 14; Grossman and Benson, 1967, Kans. 

Univ. Paleont. Contr., Ecology, Art. 1, p. 64a, pi. 11, 

figs. 4, 7, pi. 16, figs. 13-18; Swain, 1968, U.S. Geol. 

Survey Prof. Paper 573-D, p. 7, pi. 1, figs. 5a-c; pi. 

7, figs, la, b. Valentine 1971, U.S. Geol. Survey Prof. 

Paper 683-D, pi. 2, figs. 48, 49.

Occurrence. The species occurs in the lower 

Yorktown Formation at locality 3, as well as in the 

underlying Miocene formations of the area. It has 

previously been found throughout the Miocene of 

the Atlantic Coastal Plain, in the Pliocene Waccamaw Formation, and in the Holocene of Chesapeake 

Bay and the Gulf of Mexico region.

Number of specimens studied. 25 + .

Ecology. The species lives at present in lagoonal 

and near-shore sublittoral typically euryhaline but 

perhaps also oligohaline environments.

Zoo geographic derivation. Its known occurrences indicate that the species originated in the 

Caribbean or Carolinian Faunal Provinces and has 

remained relatively restricted in distribution since 

early Miocene time.

Figured specimen. USNM 179515.

Haplocytheridea bradyi (Stephenson) 

Plate 1, figures 9, 10, 13; plate 8, figures lOa, b

Cytheridea (Haplocytheridea) bradyi Stephenson 1938. 

Jour. Paleontology, v. 12, p. 129, pi. 23, fig. 22, pi. 24, 

figs. 5, 6, text fig. 10.

Haplocytheridea bradyi (Stephenson). Swain, 1955, Jour. 

Paleontology, v. 29, p. 618, pi. 59, figs. 12a, b; Puri, 

1960, Gulf Coast Assoc. Geol. Socs. Trans., v. 10, p. 

110, pi. 2, figs. 3, 4, pi. 6, fig. 19, text figs. 4, 5; Sandberg, 1964, Micropaleontology, v. 10, p. 362, pi. 2, figs. 7- 

16; Hulings and Puri, 1965, Pub. Staz. Zool. Napoli, 

v. 33, supp., p. 321, fig. 12; Swain, 1968, U.S. Geol. 

Survey Prof. Paper 573-D, p. 8, pi. 1, figs. 7a, b, 8a, 

b; pi. 2, fig. 8; Hall, 1965, Michigan Univ., Natl. Sci. 

Found. Proj. GB-26, Rept. 4, p. 41, pi. 11, figs. 1-11; 

Grossman and Benson, 1967, Kans. Univ. Paleont. Contr., 

Ecology, Art. 1, p. 64a, pi. 11, fig. 2, pi. 17, figs. 15, 16, 

18; Valentine, 1971, U.S. Geol. Survey Prof. Paper 

683-D, pi. 2, figs. 42, 46.

Haplocytheridea bradyi Swain, [sic] Byrne, LeRoy, and 

Riley, 1959, Gulf Coast Assoc. Geol. Socs. Trans., v. 

9, p. 240, pi. 4, fig. 10, pi. 5, fig. 11.

Cytheridea (Haplocytheridea) wadei Stephenson, 1941, 

Jour. Paleontology, v. 15, p. 428, text figs. 4, 5, 14-18.

Haplocytheridea ivadei Stephenson. Puri, 1954, Florida Geol. 

Survey Bull. 36, p. 231, pi. 3, figs. 5, 6, text fig. 3g.

Cytheridea (Haplocytheridea) proboscidiala Edwards, 1944, 

Jour. Paleontology, v. 18, pi. 508, pi. 85, figs. 8-11; 

Brown, 1958, North Carolina Dept. Conserv. Devel. 

Bull. 72, p. 58, pi. 5, fig. 14.

Haplocytheridea proboscidiala (Edwards) Benson and Coleman, 1963, Kansas Univ. Paleont. Contr., Art. 2, p. 28, 

pi. 3, figs. 4-9, text fig. 15.

Occurrence. The species is common in the Pliocene (?) at Mount Gould Landing, Bertie County,

N.C. It was recorded in the Yorktown Formation of 

Virginia and North Carolina by Hazel (1971). Also, 

in the upper Miocene, it is found in the Duplin Marl 

of North Carolina (Edwards, 1944), and in the 

Choctawhatchee Formation (of former usage) of 

Florida (Puri, 1954). It occurs in the Pliocene Waccamaw Formation of North Carolina (Swain, 1968), 

and the Caloosahatchee Marl of Florida (Stephenson, 1938). It was recorded by Valentine (1971) 

from the Pleistocene of Virginia. The species occurs 

living in the Atlantic Ocean off the coast of Virginia (Hulings, 1966), in the Gulf of Mexico (Swain, 

1955; Puri, 1960; Benson and Coleman, 1963), and 

in the Pleistocene of Louisiana (Byrne and others, 

1959).

Number of specimens studied. 25 + .

Ecology. This form, which in some collections is 

characterized by reversal of valve size and hingement, is at present a neritic, open-shelf species living on sand, silt, or carbonate-ooze bottom.

Zoogeographic derivation. The species apparently originated in the southeastern United States region of the Atlantic Ocean or Gulf of Mexico, in the 

Caribbean or Carolinian Faunal Provinces.

Figured specimens. USNM 179516-179521.

Genus CYTHERIDEA Bosquet, 1852

Cytheridea Bosquet, 1852, Acad. Royale Belgique Mem. cour.

et Mem. Sav. etrangeres, v. 24, p. 37. 

Cytheridea (Eucytheridea) Bronstein, 1930, Trav. Comm.

etude Lac Bajkal, v. 3, p. 127.

Refer to Moore and others (1961, p. 273) for a 

diagnosis of shell features of the genus. Type species, Cythere muellerii Miinster, 1830. Geologic 

range, Oligocene to Holocene.

Cytheridea sp. A

Plate 1, figures 6-8

Haplocytheridea sp. aff. H. israelskyi Stephenson. Swain, 

1952, U.S. Geol. Survey Prof. Paper 234, p. 20, pi. 

1, figs. 15-17.

Cytheridea characterized by elongate-subovate 

outline, blunt ends in edge view; surface with large 

pits and intervening ridges, arranged concentrally 

on marginal third of surface, but not medially.

The shell of this species was described previously 

(Swain, 1952) but was not given definite assignment. It now appears that the elongate-subovate outline, blunt ends in edge view, and "entomodont" 

hinge ally the species more with Cytheridea than 

with Haplocytheridea.

Length of figured specimen 0.80 mm., height 0.44 

mm., convexity 0.36 mm (pi. 1, figs. 6-8) .

Occurrence. The species occurs in the lower
14 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Yorktown Formation, at Madry's Bluff (localities 

A-l and A-6), Hertford County, N.C. It was also 

recorded previously from the upper Miocene at 

Washington, N.C., and questionably from the Oligocene in a well located at Cape Hatteras, N.C. (Swain, 

1952).

Number of specimens studied. Two.

Ecology. The species probably represents a marine shelf environment. This is indicated from species with which it is associated, such as Thaerocythere schmidtae (Malkin, 1953).

Zoogeographic derivation. Cytheridea of this 

general type occurred in Western Europe and the 

Mediterranean region in earlier Tertiary times and 

are suggested as having migrated to the western 

North Atlantic in the middle Tertiary.

Figured specimens. USNM 179522, 179523.

Cytheridea muelleri subsp. 

Plate 1, figure 5

Shell subovate in side view, highest anteromedially; dorsal margin moderately convex; ventral margin slightly sinuous, with posteromedian weak concavity; anterior margin broadly curved with four 

or five small spines ventrally; posterior margin more 

curved, strongly extended below and with one ventroposterior small spine on right valve and two or 

three small ventral spines on left valve. Left valve 

slightly larger than right, overlapping and extending beyond right along dorsal slope and part of 

terminal and ventral regions; valves moderately 

convex with convexity extending well toward ends 

and providing a blunt-ended aspect to shell, greatest 

convexity submedian. Valves ornamented by numerous rather large pits, the interspaces vary from 

equal to two times diameter of pits; in ventral and 

terminal areas, pits are roughly arranged in curving 

rows parallel to valve margins and there is a slight 

tendency for pits to occupy weak concentric furrows 

ventrally and anteriorly in right valve.

Hinge heteromerodont, that of right valve consists 

of terminal elongate crenulate teeth, having about 

eight crenulae on the anterior and seven on the 

posterior element, and an interterminal more finely 

crenulate element that changes from a furrow anteriorly to a low ridge posteriorly and is slightly 

longer than terminal tooth; hinge of left valve the 

antithesis of right. Inner lamellae rather narrow, 

broadest anteriorly; vestibules narrow; radial canals short, numerous, and apparently simple. Adductor muscle scar an anteromedian slightly curved, 

subvertical row of four closely spaced spots and two

additional more anterior spots both U-shaped, open 

dorsally, the upper of which is larger.

Length of figured specimen 0.83 mm, height 0.47 

mm, convexity 0.42 mm.

Relationships. The general shape, ornamentation, and internal shell structures of this subspecies 

are closely similar to those of C. muelleri (Miinster, 

1830) from the upper Oligocene (Chattian) of 

Europe. The present subspecies is less elongate and 

has wider surface interspaces than is typical of C. 

muelleri s. s.

Occurrence. Yorktown Formation, middle part, 

locality C-l, Nansemond County, Va.

Number of specimens studied. Two.

Ecology. The habitat of the subspecies is believed by the author to have been an open marine 

shelf in sublittoral to neritic depths.

Zoogeographic derivation. The forms of this type 

are believed by the writer to have originated in the 

Mediterranean or eastern North Atlantic region in 

Paleogene time and to have migrated to the western 

North Atlantic in the Neogene.

Figured specimens. USNM 179524.

Cytheridea sp. B

Plate 1, figures 4, 11, 12

Cytheridea is characterized by fine punctation of 

surface, the punctae averaging 0.025 mm in diameter 

with interspaces ranging from two to three times 

diameter of pits; outline elliptical-subovate.

Shell elongate, subelliptical-subovate in side view, 

highest about one-fourth from anterior end; dorsal 

margin nearly straight, slightly more convex in 

right than in left valve; ventral margin slightly concave medially; anterior margin broadly curved, 

slightly extended below and with five to six small 

spines ventrally; posterior margin more narrowly 

curved, also slightly extended below and with small 

posteroventral spines in right valve. Valves not 

strongly convex, greatest convexity median; left 

valve slightly larger than right. Valve surface of 

illustrated specimen somewhat worn, but bears 

numerous medium-sized pits, averaging 0.025 mm in 

diameter and variably spaced; the interstices range 

from the same as to more than three times the diameter of the pits.

Hinge heteromerodont, that of right valve consists of anterior elongate hinge element having about 

eight denticles, a posterior element also containing 

seven or eight denticles, and an interterminal structure that consists of a shallow crenulate groove anteriorly which passes posteriorly into a low crenulate bar; interterminal structure is somewhat longer
SYSTEMATIC DESCRIPTIONS 15

than either of the terminal teeth; hinge of left valve 

is the antithesis of that of right valve. Inner lamellae 

of moderate width, broadest anteriorly and with 

narrow vestibules terminally; radial canals numerous and simple; adductor muscle scar is an anteromedian subvertical row of four small spots, and 

there are two, more anterior, large spots, the upper 

spot is crescentic and points dorsally, the lower spot 

is elongate.

Length of figured specimen 0.87 mm, height 0.45 

mm, convexity 0.37 mm.

Relationships. This species is similar in shape to 

C. pernota Oertli and Key, 1955 from the Chattian 

and Rupelian Stages (upper Oligocene) of Europe, 

but that form is more coarsely punctate than the 

present species. Clithrocytheridea virginiensis Malkin, 1953 is similar in shape and ornamentation but 

as described by Malkin (1953) has an interterminal 

groove in hinge of right valve typical of Clithrocytheridea rather than the combined right valve groove 

passing posteriorly into a bar as in the present 

species and in Cytheridea.

Occurrence. The species is rare in the middle 

part of the Yorktown Formation, locality C-l, 

Nansemond County, Va.

Number of specimens studied. Two.

Ecology. The species probably represents a 

neritic or sublittoral shallow open-shelf environment.

Zoogeographic derivation. This group of species, 

including that referred to from the Chattian and 

Rupelian Stages of Europe are believed by the writer 

to have originated in western Europe in the Paleogene and to have migrated to North America in the 

Neogene.

Figured specimen. USNM 179525.

Subfamily EUCYTHERINAE Puri, 1954 

Genus EUCYTHERE Brady, 1868

Cytheropsis Sars, 1866, Oversigt af Norges Marine Ostracoder, p. 57 [non M'Coy, 1849]. 

Eucythere Brady, 1868, Mon. Recent British Ostracoda,

Linnean Soc. London Trans. v. 26, p. 429.

A diagnosis of the shell of the genus is given in 

Moore and others (1961, p. 285). Type species, Cythere declivis Norman, 1865. Geologic range, Upper 

Cretaceous to Holocene.

Eucythere triangulata Puri

Plate 1, figure 16

Eucythere triangulata Puri, 1954, Florida Geol. Survey 

Bull. 36, p. 300, pi. 16, figs. 7, 8, text fig. 135; Hall, 

1965, Michigan Univ., Natl. Sci. Found. Proj. GB-26, 

Rept. 4, p. 43, pi. 2, figs. 8-11.

Occurrence. Rare in middle part of Yorktown

Formation, locality D-l, Suffolk, Nansemond County, Va. The species was described from the Area and 

Ecphora facies of the Choctawhatchee Formation 

(of former usage) of Florida (Puri, 1954) ; it has 

also been recorded from the Holocene of Georgia 

(Hall, 1965).

Number of specimens studied. Two.

Ecology. The species is associated at locality D-l 

with numerous other forms that, judging from living 

representatives, are now found on the open continental Atlantic shelf off the Middle Atlantic States 

in the neritic and sublittoral environment.

Zoogeographic derivation. The origin of this species is not known. Close relatives occur in the North 

Atlantic, Mediterranean, and Gulf of Mexico-Caribbean region at the present time and fossil representatives are present in the Late Cretaceous and early 

and late Tertiary of the Gulf of Mexico region and 

the Atlantic Coastal Plain, and in the Jurassic, Cretaceous, and Tertiary of Europe.

Figured specimen. USNM 179526.

Subfamily NEOCYTHERIDEIDINAE Puri, 1957 

Genus CUSHMANIDEA Blake, 1933

Cytherideis Auctorum, not Jones, 1856, Forbes' Tert. Fluv.-

Mar. Fm. Isle of Wight, Great Britain Geol. Survey

Mem., 157 [= Cypridea Bosquet]. 

Cushmanidea Blake, 1933, in W. Procter, 1933, Biological

Survey of the Mount Desert region, pt. 5, p. 232. 

tSacculus Neviani, 1928, Pontif. Acad. Sci., Rome, Mem.

Ser. 2, v. 11, p. 72 [not Gosse, 1851 or Hirase, 1927]. 

Hemicythcrideis Ruggieri, 1952, Bologna Univ. 1st. Zool.,

Nota del Lab. Biol. Marina di fano, v. 1, p. 62.

A diagnosis of the genus was given by Moore and 

others (1961, p. 290). Type species, Cytheridea 

seminuda Cushman, 1906. Geologic range, Eocene to 

Holocene.

Cushmanidea fabula (Howe and Dohm)

Plate 1, figure 20; plate 8, figures 4a, b

Cytherideis fabula, Howe and Dohm, 1935, Florida Geol. 

Survey Bull. 13, p. 14, pi. 3, figs. 15, 16, 20, 23, pi. 4, 

fig. 2; Puri, 1952, Jour. Paleont., v. 26, p. 911, pi. 130, 

fig. 14, text figs. 3, 4; Puri, 1954, Florida Geol. Survey 

Bull. 36, p. 287, pi. 9, fig. 14.

Cushmanidea fabula (Howe and Dohm). Puri, 1958, Gulf 

Coast Assoc. Geol. Socs. Trans. v. 8, p. 174, table 1.

Occurrence. In the present collection the species 

was obtained from the lower Yorktown Formation, 

locality N-l, Surry County, Va. It was described 

from the Area Zone of the Choctawhatchee Formation (of former usage) of Florida (Howe and others, 

1935), and was also recorded from the Chipola Formation and Oak Grove member of the Shoal River
16 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Formation of Florida (Puri, 1954). Its range is 

interpreted as lower to upper Miocene.

Number of specimens studied. Two.

Ecology. The species probably inhabited a sublittoral inner marine shelf environment judging 

from the species with which it is associated.

Zoogeographic derivation. The origin of the species is not known but judging from its occurrence 

may have originated in the eastern Gulf of Mexico 

or adjacent Atlantic Ocean, in the Caribbean or 

Carolinian Faunal Provinces.

Figured specimen. USNM 179527.

Cushmanidea ulrichi (Howe and Johnson) 

Plate 1, figure 25

Cytherideis tilrichi Howe and Johnson, 1935, Florida Geol.

Survey Bull. 13, p. 16, pi. 3, figs. 11-14; Puri, 1952,

Jour. Paleontology, v. 26, p. 911, pi. 130, figs. 11-13. 

Cushmanidea ulrichi (Howe and Johnson). Puri, 1958, Gulf

Coast Assoc. Geol. Socs. Trans., v. 8, p. 174, table 1;

Grossman and Benson, 1967, Kans. Univ. Paleont.

Contr., Ecology, Art. 1, p. 67, pi. 14, fig. 3, pi. 19, fig. 2.

Remarks. As seen by transmitted light (pi. 1, 

fig. 25) the radial canals of the species are numerous 

terminally and are fewer and more widely spaced 

ventrally; the line of concrescence and inner margin 

are well separated anteriorly; the adductor muscle 

scar consists of a curved row of four spots; there are 

two "frontal spots" the dorsal of which is roughly 

V-shaped.

Occurrence. The species is present throughout 

the Yorktown Formation in the area studied. It was 

described from the Chipola Formation, the Oak 

Grove member of the Shoal River Formation and the 

Choctawhatchee Formation (of former usage) in 

Florida (Howe and others, 1935; Puri, 1954), middle and upper Miocene. It has also been recorded 

from the Holocene of Pamlico Sound.

Number of specimens studied. Seven.

Ecology. The species is living in the Atlantic 

Ocean on the open shelf off Virginia.

Zoogeographic derivation. As far as can be determined, the species originated in the Western 

Middle Atlantic Virginian or Carolinian Faunal 

Provinces.

Figured specimen. USNM 179528.

Genus PONTOCYTHERE Dubowsky, 1939

Pontocythere Dubowsky, 1939, Trav. Sta. Bol. Karadagh, v. 

5, p. 25.

The status of the genus has recently been reviewed 

by Hulings (1966). Type species, P. tchernjawksii 

Dubowsky, 1939. Geologic range, Miocene to 

Holocene.

Subgenus Hulingsina Puri, 1958

Hulingsina Puri, 1958, Gulf Coast Assoc. Geol. Socs. Trans., 

v. 8, p. 173.

The characteristics of the shell of Hulingsina were 

described by Puri (1958) and by Moore and others 

(1961). It is here considered to be a subgenus of 

Pontocythere in which the shell is more strongly 

punctate or pustulose and more angulated posteriorly 

than in typical Pontocythere. Type species H. tuberculata Puri, 1958. Geologic range, Miocene to 

Holocene.

Pontocythere (Hulingsina) ashermani (Ulrich and Bassler)

Plate 1, figures 21, 24; plate 2, figures 1-3; plate 9, figures

12a, b

Cytherideis ashermani Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene volume, p. 126, pi. 37, figs. 10- 

16; Howe and others, 1935, Florida Geol. Survey Bull. 

13, p. 14, pi. 3, figs. 8-10; Swain, 1948, Maryland Dept. 

Geology, Mines, and Water Resources Bull. 2, p. 195, 

pi. 14, fig. 1; Swain, 1952, U.S. Geol. Survey Prof. 

Paper 234-A, p. 19; Puri, 1952, Jour. Paleontology, v. 

26, p. 910, pi. 13, figs. 4-8, text figs. 1, 2; Puri, 1954, 

Florida Geol. Survey Bull. 36, p. 286, pi. 9, figs. 4-8; 

Malkin, 1953, Jour. Paleontology, v. 27, p. 778, pi. 78, 

figs. 1-3.

Cytherideis longula Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene volume, p. 128, pi. 37, figs. 21- 

27; Swain, 1948, Maryland Dept. Geology, Mines, and 

Water Resources Bull. 2, p. 195, pi. 13, fig. 2.

Cytherideis semicircularis Ulrich and Bassler, 1904, Maryland Geol. Survey, Miocene volume, p. 127, pi. 37, figs. 

18-20.

Cushmanidea ashermani (Ulrich and Bassler). McLean, 

1957, Bulls. Am. Paleontology, v. 38, no. 167, p. 77, pi. 

8, figs. 5a-f; Brown, 1958, North Carolina Dept. Conserv. Devel. Bull. 72, p. 67, pi. 8, fig. 9; Hall, 1965, 

Michigan Univ. Natl. Sci. Found. Proj. GB-26, Rept. 

4, p. 39, pi. 12, figs. 14-17.

Hulingsina ashermani (Ulrich and Bassler). Puri, 1958, 

Gulf Coast Assoc. Geol. Socs. Trans., v. 8, p. 173; 

Benson and Coleman, 1963, Kans. Univ. Paleont. Contr., 

Arthropoda, Art. 8, p. 45, pi. 6, fig. 5, pi. 8, figs. 1-3; 

Hulings and Puri, 1965, Pub. Staz. Zool., Napoli, v. 33, 

supp., p. 323, fig. 12A; van den Bold, 1963, Am. Assoc. 

Petroleum Geologists Bull., v. 47, p. 698; Grossman and 

Benson, 1967, Kansas Univ. Paleont. Contr., Ecology, 

Art. 1, p. 68, pi. 14, fig. 2 pi. 20, figs. 13, 14.

Pontocythere ashermani (Ulrich and Bassler). Hulings, 1966, 

Chesapeake Sci., v. 7, p. 51, figs. 2a-g, 6N; Swain, 1968, 

U.S. Geol. Survey Prof. Paper 573-D, p. 10, pi. 2, figs, 

la-d, pi. 6, fig. 4, text fig. 8.

Remarks. As observed by transmitted light (pi. 

9, figs. 12a, b) the radial canals of the species terminate just within outer margin of valve; canals continue along venter but are fewer and more widely 

spaced than terminally.

Occurrence. In the present collection the species 

ranges throughout the Yorktown and Duplin Forma-
SYSTEMATIC DESCRIPTIONS 17

tions and is also present in the Middle Miocene and 

in the Pliocene Waccamaw Formation (also see 

Hazel, 1971). It has previously been recorded also in 

the Miocene of Florida (Puri, 1954) and is living in 

the Atlantic Ocean off Virginia (Hulings, 1966). A 

report of living representatives off the west coast of 

Florida (Hulings and Puri, 1965) is less well substantiated (Swain, 1968). According to van den 

Bold (1968), this group of species does not range 

south of Guatemala either in living or in fossil forms.

Number of specimens studied. 100+ .

Ecology. The species is characteristic of an open 

marine shelf habitat in sublittoral to neritic depths.

Zoogeographic derivation. The species evidently 

appeared in the Middle Atlantic region in early Neogene time and is of Boreal or Arctic North Atlantic 

origin, but its ancestral relationships are uncertain.

Figured specimens. USNM 179529-179537.

Pontocythere (Hulingsina) cf. P. (H.) rugipustulosa (Edwards)

Plate 1, figure 18; plate 2, figures 4-7

Cytherideis rngipnstulosa Edwards, 1944, Jour. Paleontology,

v. 18, p. 514, pi. 86, figs. 5-7. 

Pontocythere rugipustulosa (Edwards). Swain, 1968, U.S.

Geol. Survey Prof. Paper 573-D, p. 9, pi. 1, fig. 10,

text fig. 7. Valentine, 1971, U.S. Geol. Survey Prof.

Paper 683-D, pi. 3, figs. 17, 18, 21, 22, 25, 26, 29, 30.

Remarks. The writer (Swain, 1968) referred to 

this species a form that is ornamented by linearly 

arranged rows of nodes. This form is somewhat 

atypical in that the species commonly seems to have 

surface ridges on which lie nodes. At present, the 

relationship between P. wilberti (Puri, 1952) which 

is ornamented by linearly arranged but more widely 

spaced nodes and P. rugipustulosa is not entirely 

clear. This immature form resembles molt valves of 

P. ashermani (Ulrich and Bassler, 1908) but the 

surface bears longitudinal and concentric ridges and 

few or no pits which suggests P. rugipustulosa.

Occurrence. Rare in beds of Pliocene (?) age, 

locality G-3, Bertie County, N.C. (also see Hazel, 

1971). The species has also been found in the Duplin 

Marl (Edwards 1944), the Choctawhatchee Formation (of former usage) of Florida (Puri, 1952, 1954), 

the Yorktown Formation of Virginia and North 

Carolina (Malkin, 1953; Hazel, 1971), and the subsurface middle (?) and upper Miocene of North Carolina (Swain, 1952). It was recorded from the Pleistocene of Virginia by Valentine (1971).

Number of specimens studied. Four.

Ecology. The species probably lived in a sublittoral inner neritic marine shelf environment judging from the species with which it is associated.

Zoogeographic derivation. The species apparently originated in the western Atlantic Ocean in the 

Carolinian or Caribbean Faunal Provinces off the 

southeastern United States or nearby western Gulf 

of Mexico based on its distribution.

Figured specimens. USNM 179538.

Pontocythere (Hulingsina) agricola duopunctata, n. subsp.

Plate 1, figure 22; plate 2, figures 8-10

Diagnosis. P. agricola (Howe and Hadley, 1935) 

in which surface pitting on posterior part of shell is 

finer than that on anterior and ventral parts of shell.

This subspecies differs from P. agricola agricola 

Howe and Hadley, 1935 in that the surface pitting of 

the posterior part of the shell is considerably coarser 

than that lying in concentric rows in the anterior 

and ventral parts of the shell.

Length of holotype specimen (pi. 2, fig. 8-10) 

0.87 mm, height 0.60 mm, convexity 0.37 mm; type 

horizon and locality, Upper Yorktown Formation, 

locality K-4, Dinwiddie County, Va.

Occurrence. In the present collection the new 

subspecies occurs in the lower part of the Yorktown 

Formation at locality A-l, Hertford County, N.C., 

and in the middle part of the Yorktown Formation, 

locality C-l, Nansemond County, Va.; locality K-4, 

Dinwiddie County, Va.; and in beds of Pliocene (?) 

age, locality G-3, Bertie County, N.C.

Number of specimens studied. Five.

Ecology. The subspecies probably inhabited an 

open marine shelf at sublittoral to neritic depths 

judging from the other ostracodes with which it is 

associated.

Zoogeographic derivation. The subspecies apparently originated in the western Atlantic Ocean in 

the Carolinian Faunal Province.

Figured specimens. USNM 179539-179543.

Genus NEOCYTHERIDEIS Puri, 1952

Neocytherideis Puri, 1952, Jour. Paleontology, v. 26, p. 912. 

ISahnia Puri, 1952, Jour. Paleontology, v. 26, p. 912.

A diagnosis of the shell features was given by 

Moore and others, (1961, p. 290). Type species N. 

elongatus ( = Cytherideis subulata var. fasciata; 

Brady and Robertson, 1874). Geologic range, Miocene to Holocene.

Neocytherideis sp.

Plate 3, figure 23

Shell elongate, subquadrate-subelliptical in side 

view, highest about one-third from anterior end; 

dorsal margin nearly straight, about two-thirds of 

shell length, with broadly obtuse anterior cardinal
18 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

marginal bend; ventral margin nearly straight, 

longer than dorsal margin, and subparallel to it; 

anterior margin rounded and strongly extended below; posterior margin more broadly curved and extended medially. Valves compressed, subequal, the 

left slightly the larger; greater convexity posteromedian. Valve surface finely and densely pitted.

Hinge of left valve consists of an anterior elongate socket, open ventrally and bearing a few transverse marks, an interterminal faintly crenulate 

hinge surface formed of valve edge, and a posterior 

elongate socket, open ventrally; adductor muscle 

scar consists of a median compact group of four subparallel elongate spots and a more anterior crescentic ("frontal") spot; between these two areas 

is another spot that may represent the mandibular 

pivot site rather than the so called mandibular muscle scar itself. Inner lamellae broad anteriorly, less 

broad elsewhere, line of concrescence and inner margin separated, especially anteriorly; line of concrescence scalloped due to funnellike inner terminations of radial canals; these canals are rather few, 

straight, and widely spaced, but continue along all 

the free margin.

Length of figured left valve 0.44 mm, height 0.19 

mm, convexity of valve 0.11 mm.

Relationships. The general shape, hingement, 

musculature, and marginal structures relate this 

species to Neocytherideis Puri, 1952; the subquadrate shape and musculature are reminiscent of Copytus Skogsberg, 1939 but that genus has a weaker 

hinge and a less scalloped line of concrescence.

Occurrence. Rare in Yorktown Formation, middle part, locality S-l, James County, Va.

Number of specimens studied. Two.

Ecology. The species represents an open-shelf 

marine environment judging from the associated 

ostracodes.

Zoogeographic derivation. Unknown, but possibly arose in the western Atlantic Ocean in the Carolinian Faunal Province.

Figured specimens. USNM 179544.

Family CYTHERURIDAE Muller, 1894 

Genus CYTHERURA Sars, 1866

Cytherura Sars, 1866, Oversight af Norges Marine Ostracoder, 

p. 69.

A brief description of the shell characteristics of 

the genus was provided by Moore and others (1961, 

p. 292). Type species, Cythere gibba 0. F. Muller, 

1785. Geologic range, Cretaceous to Holocene.

Cytherura cf. C. gibba Muller

Plate 3, figures 4a, b

Cytherura gibba (Muller). Sars, 1866, Oversigt af Norges 

Marine Ostracoder (1865), p. 70.

Occurrence. Rare in beds of Pliocene (?) age, locality G-3 Bertie County, N.C. The species is living 

in brackish waters in Great Britain, Scandinavia, 

Holland, and Germany; and is fossil in the Pleistocene of Scotland, Norway (Brady and Norman, 

1889), Eastern United States and Baja California.

Number of specimens studied. One.

Ecology. The modern representatives of the species inhabit brackish waters (Brady and Norman, 

1889). The upper Yorktown specimen was obtained 

from a sample that includes Cytheromorpha warneri 

Howe and Spurgeon, 1935, another possible brackishwater form. The other associated species, however, 

do not necessarily imply brackish water conditions, 

that is, Actinocythereis exanthemata (Ulrich and 

Bassler, 1904) ; Costa bar clay i (McLean, 1957) and 

others. The forms illustrated by Tressler and Smith 

(1948) from Chesapeake Bay may not be this species 

(Benson, 1959) but were found most abundantly in 

late summer at water temperatures of 20°-25°C, as 

well as in small numbers throughout the year.

Zoogeographic derivation. The species may have 

originated in the Atlantic region off North America 

in the Neogene and from there migrated to northwestern Europe.

Figured specimen. USNM 179545.

Cytherura forulata Edwards

Plate 2, figure 22; Plate 3, figures 5, 6

Cytherura forulata Edwards, 1944, Jour. Paleontology, v. 

18, p. 526, pi. 38, figs. 17-20; Swain 1955, Jour. 

Paleontology, v. 29, p. 628, pi. 64, figs. 10 a-c, text figs. 

35c, 39-2, a, b; Puri, 1960, Gulf Coast Asoc. Geol. Socs. 

Trans. v. 10, p. 115, pi. 4, figs. 16, 17; Hulings and 

Puri, 1965, Pub. Staz. Zool., Napoli, v. 33, supp., p. 329, 

fig. 14; Grossman and Benson, 1967, Kansas Univ. 

Paleont. Contr., Ecology, Art. 1, p. 69, pi. 13, fig. 5, 

pi. 19, fig. 8; Swain, 1968, U.S. Geol. Survey Prof. 

Paper 573-D, p. 12, pi. 5, fig. 10, text fig. 10; Valentine 

1971, U.S. Geol. Survey Prof. Paper 683-D, pi. 2, fig. 

25, 26.

Occurrence. The species was found in the present collection to be rare in the beds of Pliocene (?) 

age at localities G-3 and Mount Gould; rare in upper 

Yorktown Formation at localities H-l and H-3, 

Bertie County, N.C.; rare to frequent in the middle 

Yorktown at localities S-3 and S-4, James County, 

Va., C-l and C-2, Nansemond County, Va.; rare to 

frequent in the lower Yorktown Formation at localities A-l, A-3, and A-5, Hertford County, N.C., 

and locality U-l, Essex County, Va.
SYSTEMATIC DESCRIPTIONS 19

The species also occurs in the upper Miocene Duplin Marl of North Carolina (Edwards, 1944), the 

Pliocene Waccamaw Formation of South Carolina 

(Swain, 1968), in the Pleistocene of Virginia (Valentine, 1971), and is reported to be living off the 

west coast of Florida (Puri, 1960; Hulings and Puri, 

1965).

In the present collection it also ranges down into 

the upper St. Marys Formation of Maryland.

Number of specimens studied. 29.

Ecology. The species at present in the western 

Florida area lives in both normal-salinity sublittoral 

environments and in reduced-salinity sublittoral environments but is more abundant in the former. It 

also shows a preference for sand-mud bottoms.

Zoo geographic derivation. The species seems to 

have originated in the Carolinian or Caribbean 

Faunal Provinces in late Miocene time.

Figured specimens. USNM 179546, 179547.

Cytherura elongata Edwards

Plate 3, figures 1-3; plate 8, figures 7a, b; plate 9, figure 2

Cytherura elongata Edwards, 1944, Jour. Paleontology, v. 

18, p. 526, pi. 88, figs. 21-25; Swain, 1952, U.S. Geol. 

Survey Prof. Paper 234-A, p. 50, pi. 7, figs. 23, 25; 

Brown, 1958, North Carolina Dept. Conserv. Devel. Bull. 

72, p. 59, pi. 7, fig. 5; Hulings and Puri, 1965, Pub. Staz. 

Zool., Napoli, v. 33, supp., p. 331, fig. 15; Grossman and 

Benson, 1967, Kansas Univ. Paleont. Contr., Ecology, 

Art. 1, p. 69, pi. 13, fig. 6, pi. 19, figs. 9, 10, 14; Swain, 

1968, U.S. Geol. Survey Prof. Paper 573-D, p. 12, pi. 6, 

figs, lla-c.

Remarks. The radial canals of the species are 

relatively few, as seen by transmitted light (pi. 8, 

figs. 7a, b; pi. 9, fig. 2), do not reach outer margin 

and tend to occur in pairs ventrally.

Occurrence. The species is rare in beds of Pliocene (?) age, locality G-3, Bertie County, N.C.; in 

the upper Yorktown Formation at locality H-2, 

Bertie County, N.C.; in the middle Yorktown it is 

common at locality S-4, James County, Va., rare at 

localities R-l and R-2, Isle of Wight County, Va., 

rare at locality K-3, Dinwiddie County, Va.; and 

rare at localities C-l, C-2, and D-l, Nansemond 

County, Va.; rare to frequent in the lower Yorktown 

at localities A-l, A-3, and A-5 Hertford County, 

N.C. It was described from the upper Miocene Duplin Marl of North Carolina (Edwards, 1944) ; also 

occurs in the Pliocene Waccamaw Formation of 

North and South Carolina (Swain, 1968) and has 

been found living off the west coast of Florida (Hulings and Puri, 1965).

Number of specimens studied. 25 + .

Ecology. The species lives at present in sublittoral euhaline to oligohaline environments and prefers sand-mud bottoms (Hulings and Puri, 1965).

Zoogeographic derivation. The species seems to 

have originated in the Carolinian or Caribbean 

Faunal Provinces in the late Miocene.

Figured specimens. USNM. 179548-179550.

Genus CYTHEROPTERON Sars, 1866

Cytheropteron Sars, 1866, Oversigt af Norges Marine

Ostracoder, p. 79. 

Aversovalva Hornibrook, 1952, New Zealand Geol. Survey

Paleont. Bull. 18, p. 57.

A diagnosis of the shell of the genus was given 

by Moore and others (1961, p. 292). Type species, 

Cythere latissima Norman, 1865 (= Cytheropteron 

convexum Sars, 1866). Geologic range, Upper Jurassic to Holocene.

Cytheropteron subreticulatum van den Bold

Plate 3, figures 7, 8; plate 9, figure 3

Cytheropteron subreticulatum van den Bold, 1946, Contr.

study Ostracoda, Amsterdam, de Bussy, p. 113, pi. 14,

fig. 6. 

Cytheropteron cf. C. subreticulatum van den Bold. Swain,

1952, U.S. Geol. Survey Prof. Paper 234-A, p. 48, pi. 7,

figs. 11, 13. Brown, 1958, North Carolina Dept. Conserv.

Devel. Bull. 72, p. 59, pi. 7, fig. 10.

Remarks. As shown in transmitted light view, 

the species has few radial canals and anteriorly these 

tend to open funnel-shaped on line of concrescence.

Occurrence. The species was found in this collection : rare in the lower Yorktown, at localities A-l 

and A-2, Hertford County, N.C., locality M-l, Surry 

County, Va.; rare to frequent in the middle Yorktown at localities S-l and S-3, James County, Va. 

and C-l, C-2, D-l and D-2, Nansemond County, and 

R-3, Isle of Wight County, Va. It was described from 

the Miocene of Cuba (van den Bold, 1946) and was 

recorded from the subsurface of North Carolina 

(Swain, 1952). The species also occurs in the upper 

Choptank Formation, middle Miocene of Calvert 

County, Md.

Number of specimens studied. 13.

Ecology. The species apparently lived in sublittoral or neritic marine environments.

Zoogeographic derivation. This species seems to 

have originated in the Caribbean Faunal Province 

but several related species occur in western Europe.

Figured specimens. USNM. 179551-179553.

Genus HEMICYTHERURA Elofson, 1941

Cytheropteron (Hemicytherura) Elofson, 1941, Uppsala 

Univ., Zool. Bidrag fran Uppsala, v. 19, p. 314.

Hemicytherura Elofson. Hornibrook, 1952, New Zealand 

Geol. Survey Paleont. Bull. 18, p. 58.
20 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

A diagnosis of the shell features of the genus was 

given by Moore and others (1961, p. 293). Type 

species, Cythere cellulosa Norman, 1865. Geologic 

range, Miocene to Holocene.

Hemicytherura howei (Puri) 

Plate 3, figures 16-21; plate 9, figures 4a, b

Kangarina howei Puri, 1954, Florida Geol. Survey Bull. 36,

346, pi. 4, fig. 7; text fig. 6i, j. 

Hemicytherura howei (Puri, 1954). Pooser, 1965, Kansas

Univ. Paleont. Contr., Arthropoda 8, p. 49, pi. 9, figs.

1-4; Swain, 1968, U.S. Geol. Survey Prof. Paper 573-

D, p. 11, pi. 4, figs. 5a, b, text fig. 9.

Remarks. The zone of concrescence in this species is very broad anteriorly as seen by transmitted 

light (pi. 9, figs. 4a, b) and the outer terminations 

of the canals occur along a scalloped submarginal 

zone.

Occurrence. The species in the present collection 

was found abundantly at locality G-3, Bertie County, 

N.C., beds of Pliocene (?) age; rarely at locality H-l, 

Bertie County, N.C., upper Yorktown Formation; 

rare to frequent at localities R-l, R-3, and R-4, Isle 

of Wight County, Va., C-l, C-2, D-l and D-2, 

Nansemond County, and S-l, James County, Va., 

middle Yorktown; rare to common at localities M-l, 

Surry County, Va., 1 mile above Seaboard Airline 

Railroad Bridge on Meherrin River, Northampton 

County, Va. and localities A-l to A-5, Hertford 

County, N.C., lower Yorktown (also see Hazel, 

1971).

Elsewhere the species occurs in the middle and 

upper Miocene Choctawhatchee Formation (of 

former usage) of Florida (Puri, 1954), the Duplin 

Marl of North Carolina (Pooser, 1965), and the 

Pliocene Waccamaw Formation of North Carolina 

and South Carolina (Swain, 1968). It also is rare in 

the Choptank Formation, middle Miocene, of 

Maryland.

Number of specimens studied. 25 + .

Ecology. The species probably inhabited sublittoral nearshore perhaps lagoonal and oligohaline 

environments judged from associated species such 

as Cytheromorpha warneri Howe and Spurgeon, 

1935, Cytherura forulata Edwards, 1944, and others.

Zoogeographic derivation. This form is closely 

related to other species of the Caribbean Faunal 

Province and may have originated in that area.

Figured specimens. USNM 179562-179566.

Genus PARACYTHERIDEA Muller, 1894 

Paracytheridea G. W. Muller, 1894, Fauna u. Flora des

Golfes von Neapel, 21 Mon., p. 340. 

IMooreina Harlton, 1933, Jour. Paleontology, v. 7, p. 21.

The shell features of the genus are diagnosed by 

Moore and others (1961, p. 299). Type species, Paracytheridea depressa Muller, 1894 (= Cytheropteron 

bovettensis Sequenza, 1880). Geologic range, 

Pennsylvanian (Mooreina), Upper Cretaceous to 

Holocene.

Paracytheridea mucra Edwards 

Plate 1, figure 23

Paracytheridea mucra Edwards, 1944, Jour. Paleontology, 

v. 18, p. 512, pi. 85, figs. 22, 23.

Occurrence. Rare in beds of Pliocene (?) age, 

locality G-3, Bertie County, N.C. The species was 

described from the Duplin Marl at Natural Well, 

Duplin County, N.C. (Edwards 1944). It was also 

recorded by Hazel (1971) from the Yorktown Formation of Virginia and North Carolina.

Number of specimens studied. One.

Ecology. Members of this genus typically occur 

in lagoonal environments in waters of reduced 

salinity.

Zoogeographic derivation. Related forms are so 

widely distributed on both sides of the Atlantic 

Ocean and in the Gulf of Mexico, Caribbean Sea, and 

eastern Pacific Ocean that it is not*possible at present to surmise the origin of this species.

Figured specimen. USNM 179567.

Paracytheridea altila Edwards 

Plate 1, figure 17

Cytheropteron nodosum Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene volume, p. 129, pi. 38, figs. 37-40 

[not Cytheropteron nodosum Brady, 1868],

Paracytheridea nodosa (Ulrich and Bassler). Howe and 

others, 1935, Florida Geol. Survey Bull. 13, p. 37, pi. 3, 

fig. 7; van den Bold, 1946, Contr. study Ostracoda, 

Amsterdam, de Bussy, p. 86, pi. 16, fig. 7; Swain, 1952, 

U.S. Geol. Survey Prof. Paper 234-A, pi. 51, pi. 3, figs. 

19-22.

Paracytheridea vandenboldi Puri, 1953, Jour. Paleontology, 

v. 27, p. 251, (new name); Malkin, 1953, Jour. Paleontology, v. 27, p. 780, pi. 79, fig. 5; Puri, 1954, Florida 

Geol. Survey Bull. 36, p. 238, pi. 3, fig. 7, text figs. 

5a, b; Swain, 1955, Jour. Paleontology, v. 29, p. 625, 

pi. 62, figs. 6a, b; McLean, 1957, Bulls. Am. Paleontology v. 38, no. 167, p. 75, pi. 8, figs. 4a, b; Brown, 

1958, North Carolina Dept. Conserv. Devel: Bull. 72, 

p. 58, pi. 8, fig. 6; Hall, 1965, Michigan Univ. Nat. 

Sci. Found. Proj. GB-26, Kept. 4, p. 49, pi. 18, figs. 22- 

30; Morales, 1966, Mexico Univ. Nac. Autonoma Inst. 

Geologia Bol. 81, p. 54, pi. 7, fig. 6. Grossman and 

Benson, 167, Kansas Univ. Paleont Contr., Ecology, Art. 

1 p. 70 pi. 12, fig. 5, pi. 17, fig. 2; Swain, 1968, U.S. 

Geol. Survey Paper 573-D, p. 11, pi. 2, figs. 4a, b.

Paracytheridea altila Edwards, 1944, Jour. Paleontology, v. 

18, p. 512, pi. 85, figs. 20, 21; van den Bold, 1968, Bulls. 

Am. Paleontology, v. 54, no. 239, p. 76, pi. 7, figs, la-d;
SYSTEMATIC DESCRIPTIONS 21

Valentine, 1971, U.S. Geol. Survey Prof. Paper 683-D, 

pi. 3, figs. 31-34.

Remarks. van den Bold (1968) has recently assembled all these forms under the name P. altila on 

grounds that they represent a variable series all 

belonging to one species.

Occurrence. This species occurs in the Yorktown and Duplin Formations (upper Miocene) of 

Virginia and North Carolina (also see Hazel, 1971). 

It also occurs in the Waccamaw Formation (Pliocene) of North and South Carolina (Swain, 1968) ; 

the Choctawhatchee Formation, Area fades (middle 

and upper Miocene of Florida (Puri, 1954), the upper Miocene of the Caribbean Region (van den Bold, 

1946, 1968), the Pleistocene of Virginia (Valentine, 

1971) and the Holocene of the Gulf of Mexico region 

(Swain, 1955, Morales, 1966).

Number of specimens studied. 23.

Ecology. The species characteristically occurs in 

lagoons and estuaries that have brackish waters at 

least part of the year but which may also approach 

normal sea water salinity. Thus the species appears 

to inhabit mixohaline (0.5-30 parts per mil) to 

euhaline (30-40 parts per mil) waters but seems to 

prefer the former.

Zoogeographic derivation. As in the case of the 

preceding species the related forms are so widely 

distributed that the origin of this species is difficult 

to determine, but its main area of distribution seems 

to have been the Caribbean Faunal Province.

Figured specimen. USNM 179568.

Genus SHATTUCKOCYTHERE Swain, n. gen.

Diagnosis. Cytherurid genus having subtrapezoidal to subovate outline, overhanging ventral surface, smooth to finely ornamented surface, and antimerodont hinge.

Description. Shell trapezoidal in side view, dorsal margin relatively short and straight; ventral 

margin longer than and subparallel to dorsum; terminal margin narrowly rounded to subacuminate, 

extended below, truncate above. Left valve larger 

than right. Valves moderately to strongly convex 

with ventral surface swollen and tending to overhang ventral margin especially posteromedially. 

Surface smooth, pitted, papillate, or reticulate.

Hinge antimerodont, that of left valve consists of 

terminal elongate crenulate sockets and interterminal finely crenulate ridge; that of right valve has 

terminal crenulate ridges and an interterminal crenulate furrow. Inner lamellae rather narrow, broadest 

anteriorly; line of concrescence and inner margin

separated anteroventrally but nearly coincide elsewhere. Radial canals relatively few and widely 

spaced.

Type-species, Cythere ? shattucki Ulrich and Bassler, 1904. Geologic range, Miocene to Recent.

Relationships. The subtrapezoidal outline, ventral subalate expansion of the valve surfaces and 

antimerodont hingement are distinguishing features 

of the genus. It is placed tentatively in the Cytheruridae although its hinge is unlike the entomodont 

type which is characteristic of the more definite 

members of that family. The forms previously referred to as Eocytheropteron yorktownensis Malkin, 

1953, and Cytheropteron ventrokurtosa Swain, 1967, 

I now believe should be placed in Shattuckocythere. 

Nipponocythere Ishizaki, 1971, from the Holocene of 

Japan is similar to the present genus, but has a 

ventral longitudinal ridge on the valve surface.

Shattuckocythere shattucki (Ulrich and Bassler)

Plate 1, figure 14; plate 8, figure 9

Cytheret shattucki Ulrich and Bassler, 1904, Maryland

Geol. Survey, Miocene volume, p. 121, pi. 38, fig. 10. 

Paracytherideal wetherellii (Jones, 1854). Swain, 1952,

U.S. Geol. Survey, Prof. Paper 234-A, p. 11, pi. 7, figs.

2-4; Brown, 1928, North Carolina Dept. Conserv. Devel.

Bull. 72, p. 49, pi. 8, fig. 8. 

Paracytheridea shattucki (Ulrich and Bassler, 1904). Malkin,

1953, Jour. Paleontology, v. 27, p. 780, pi. 79, figs. 6-9. 

Paracytherideal shattucki Malkin, 1953. Hall, 1965, Michigan

Univ. Natl. Sci. Found. Proj. GB-26, Kept. 4, p. 49,

pi. 18, figs. 12-21.

Remarks. The shell characteristics of the type 

species were described recently by Hall (1965).

Occurrence. In the present collections the species 

has been obtained at locality P-l, Isle of Wight 

County, Va., middle Yorktown, and locality C-l, 

Nansemond County, Va., Gibson's localities FP-1 

(0.5 of a mile south of Flag Pond, Calvert County, 

Md.) and Y-2 (Drum Cliff, near Jones Wharf, St. 

Marys County, Md.) from the Choptank Formation, 

middle Miocene, from which it has been recorded 

previously by Ulrich and Bassler (1904) and by 

Malkin (1953). A form that probably represents the 

same species was obtained from the subsurface middle Miocene of North Carolina (Swain, 1952) and 

refp^-red to Cythere wetherellii Jones, 1854. The 

writer now doubts that Jones' species occurs in the 

North Carolina Miocene. It has not been possible in 

the present work to verify Malkin's (1953) subspecies curta in ;he Yorktown Formation of this 

region. The spores has also been recorded from the 

Holocene of Georgia (Hall, 1965), as reworked? 

material.
22 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Number of specimens studied. Five.

Ecology. The associated species indicate that this 

species inhabited an open marine shelf, sublittoral 

and neritic environment.

Zoogeographic derivation. This species is believed to have originated in Paleogene time in the 

Arctic or Boreal Atlantic Faunal Provinces. "Cythere" wetherellii Jones, 1854 of the Eocene of Western Europe may represent one of the primitive members of this group.

Figured specimens. USNM 179569-179570.

Shattuckocythere similis (Malkin) 

Plate 1, figure 19a, b; plate 9, figure 14

Paracytheridea similis Malkin, 1953, Jour. Paleontology, v. 

27, p. 781, pi. 79, figs. 13, 14.

Occurrence. This form, which is somewhat more 

elongate and with longer hinge line and coarser surface reticulations than S. shattucki (Ulrich and 

Bassler, 1904) was obtained from Mount Gould 

Landing, Bertie County, N.C., in the beds of Pliocene (?) age. It was first described from the upper 

Yorktown Formation (Malkin, 1953).

Number of specimens studied. Seven.

Ecology. This form appears to represent an open 

shelf marine environment at sublittoral to neritic 

depths.

Zoogeographic derivation. The species like the 

preceding one apparently originated in Paleogene 

time in the Arctic or Boreal Atlantic Faunal 

Provinces.

Figured specimen. USNM 179571, 179572.

Shattuckocythere yorktownensis (Malkin)

Plate 3, figures 9-15; plate 9, figures 9a, b

Eocytheropteron yorktownensis Malkin, 1953, Jour. Paleontology, v. 27, p. 780, pi. 79, figs. 1-4.

Cytheropteron yorktownensis (Malkin). Swain, 1968, U.S. 

Geol. Survey Prof. Paper 573-D, p. 13, pi. 4, figs. 7ac, text fig. 11.

Remarks. On the basis of its hingement and surface ornamentation, this species is here transferred 

to Shattuckocythere. As viewed by transmitted light, 

the normal canals of the species are widely spaced 

and of fairly large size (pi. 9, figs. 9a, b). The radial 

canals are few and widely spaced.

Occurrence. In the samples studied here, the species was found to be rare in beds of Pliocene (?) age 

at Mount Gould Landing and in the upper Yorktown 

Formation at locality H-l, Bertie County, N.C.; rare 

to frequent in the middle Yorktown at localities S-3, 

James County, Va., P-l, R-l and R-2, Isle of Wight 

County, Va., C-l and C-2, Nansemond County, Va.;

rare in the lower Yorktown at localities A-l, A-2, 

and A-5, Hertford County, N.C. (also see Hazel, 

1971). It also is present in samples from the Duplin 

Marl at Kenansville, Duplin County, N.C. and at 

Walkers Bluff, Bladen County, N.C.

It previously was recorded from the Yorktown 

Formation of Virginia (Malkin, 1953), from the 

Pliocene Waccamaw Formation of North Carolina, 

and from the Pleistocene of South Carolina (Swain, 

1968).

Number of specimens studied. 26.

Ecology. S. yorktownensis is associated with 

abundant Aurila conradi Howe and McGuirt, 1935, 

Cytherura spp., Campylocythere spp. and others that 

indicate sublittoral to neritic environments.

Zoogeographic derivation. The species is of uncertain derivation because of its unique shell form. 

It may have originated in the Carolinian or Caribbean Faunal Provinces as closely related forms occur in the Miocene of Florida (Cytheropteron leonensis Puri, 1954). Another similar form is presently 

living in the Gulf of California (S. ventrokurtosa 

(Swain, 1967)) and other Pacific coast localities 

(Swain, 1967; McKenzie and Swain, 1967).

Figured specimens. USNM 179554-179561.

Family BRACHYCYTHERIDAE Puri, 1954 

Subfamily PTERYGOCYTHERINAE Puri, 1957

Genus PTERYGOCYTHEREIS Blake, 1933

Fimbria Neviani, 1928, Pontif. Acad. Sci., Rome, Mem.

Ser. 2, v. 11, p. 72 [not Bohadsch, 1761; or Risso, 1826;

or Cobb, 1894; or Belon, 1896]. 

Cythereis (Pterygocythereis) Blake, 1933, in W. Procter,

1933, Biological Survey of the Mount Desert region,

pt. 5, p. 239. 

Pterigocythereis van den Bold, 1946, Contr. study Ostracoda, Amsterdam, de Bussy, p. 29 [error].

A diagnosis of the genus was given by Moore and 

others. (1961, p. 267). Type species, Cythereis 

jonesii Baird. Geologic range, Cretaceous (?), 

Eocene (?), Miocene to Holocene.

Hazel (1967) pointed out the relationships between the pterygocytherid ostracodes and the 

Brachycytheridae and Trachyleberididae. He placed 

both the Pterygocytherinae and Brachycytherinae 

as subfamilies of the Trachyleberididae on the basis 

of muscle scar patterns.

The present writer prefers to retain the Family 

Brachycytheridae on the basis of distinctive shell 

form as well as of internal shell structure.

The Pterygocytherinae perhaps should be retained 

as a subfamily of Brachycytheridae rather than suppressed as was done in Moore and others (1961).
SYSTEMATIC DESCRIPTIONS 23

Pterygocythereis americana (Ulrich and Bassler)

Plate 2, figure 11; plate 9, figure 5; plate 13, figures 2a-c

Cythereis cornuta var. americana (Ulrich and Bassler), 

1904, Maryland Geol. Survey, Miocene volume, p. 122, 

pi. 37, figs. 29-33.

Cythereis alaris Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene volume, p. 123, pi. 38, figs. 34-36.

Cythereis (Pterygocythereis} cornuta var. americana 

(Ulrich and Bassler). Howe and others, 1935, Florida 

Dept. Conserv. Geol. Bull. 2, p. 26, pi. 2, figs. 19, 21- 

24, pi. 4, fig. 24 (= P. miocenica van den Bold, by van 

den Bold (1968)) ; Swain, 1948, Maryland Dept. Geology, 

Mines, and Water Resources Bull. 2, p. 206, pi. 14, fig. 4.

Pterygocythereis cornuta americana (Ulrich and Bassler). 

Swain, 1952, U.S. Geol. Survey Prof. Paper 234-A, p. 

41; Puri, 1954, Florida Geol. Survey Bull. 36, p. 261, 

pi. 13, fig. 105, text figs. 9d-f.

Pterygocythereis americana (Ulrich and Bassler). Malkin, 

1953, Jour. Paleontology, v. 27, p. 795, pi. 80, figs. 26- 

29; Hill, 1954, Jour. Paleontology, v. 28, p. 814; McLean, 

1957, Bulls. Am. Paleontology, v. 38, p. 80, pi. 9, figs. 5ad, 6a-e; Pooser, 1965, Kansas Univ. Paleont. Contr., 

Arthropoda Art. 8, p. 34, pi. 13, figs. 3, 7, 11-14; pi. 

14, fig. 12.

[not] Pterygocythereis americana (Ulrich and Bassler). 

Hazel, 1967, U.S. Geol. Survey Prof. Paper 564, p. 39, 

pi. 4, figs. 14, 15 (^Pterygocythereis inexpectata 

Blake).

Remarks. Hill (1954) placed the forms referred 

to P. americana by Swain (1948) in his P. howei 

without giving reasons but P. howei is stated to have 

an unbroken smooth dorsal marginal ridge not an 

interrupted en enchelon sharp-edged ridge as in 

Swain's specimen from the subsurface Miocene of 

Maryland.

Hazel (1967, pi. 4, figs. 14, 15) has placed in P. 

americana a form from the Gulf of Maine that Blake 

(1929, 1933) named Cythereis (Pterygocythereis} 

inexpectata and which differs from P. americana in 

having pronounced fluting on the inner side of its 

dorsal alar ridge. Fluting of this ridge is less prominent in the specimens of P. americana in the collection being considered herein.

Hazel (1971) refers the specimens he found in the 

Yorktown Formation of North Carolina to P. inexpectata Blake. The present writer believes that the 

middle and upper Miocene Pterygocythereis of 

North Carolina are less fluted in the dorsal ridge 

and tend to be less pointed posteriorly than P. inexpectata and are more correctly placed in P. 

americana.

The records of P. americana-like forms with en 

echelon dorsal ridges from the eastern Gulf of 

Mexico (Benson and Coleman, 1963) are difficult to 

evaluate. Only seven (which they consider juveniles) 

out of 103 of their specimens were constructed like 

P. americana, whereas the others more closely resemble P. howei Hill, but are more coarsely spinose 

terminally.

In the present writer's opinion the Holocene occurrence of B. americana has not been demonstrated 

for the Gulf of Mexico.

Occurrence. The species occurs in the Miocene of 

the middle Atlantic region in the Calvert, Choptank, 

St. Marys, and lower and middle Yorktown Formations (also see Hazel, 1971). It was not found definitely in the upper Yorktown or Duplin Formations. 

In the Pliocene Waccamaw Formation a form with 

smooth dorsal ridge occurs (Swain, 1968). The species also is reported to occur in the Chipola, Shoal 

River, and Choctawhatchee 2 Formations of Florida 

(Puri, 1954). Its principal occurrence seems to be 

middle Miocene in the Atlantic coastal region. A 

striking example of its presence in marine bottom 

samples is in "Onslow Bay" off North Carolina 

where the Pungo River Formation crops out on the 

sea floor. Many specimens of P. americana were obtained from these samples.

Number of specimens studied. 25 + .

Ecology. The species represents an open marine 

shelf habitat at sublittoral to neritic depths.

Zoogeographic derivation. This form seems to 

have had its origins in the Arctic or Boreal Atlantic 

Faunal Provinces in Paleogene time and to have 

extended its range into the Carolinian and Floridian 

Faunal Provinces in the Neogene.

Figured specimens. USNM 179573.

Family CYTHERETTIDAE Triebel, 1952

Genus CYTHERETTA Muller, 1894 

Cytheretta G. W. Muller, 1894, Fauna u. Flora des Golfes

von Neapel, 21 Mon., p. 382. 

Pseudocytheretta Cushman, 1906, Boston Soc. Nat. History

Proc. v. 32, p. 382. 

Cylindrus Neviani, 1928, Pontif. Acad. Sci., Rome, Mem.

Ser. 2, v. 11, p. 72, 106 [not Deshayes, 1824; or Fitzinger, 1833; or Hermannsen, 1852]. 

Prionocytheretta Mehes, 1941, Geol. Hungarica, Ser. Pal.,

fasc. 16, p. 60.

The genus was diagnosed in Moore and others 

(1961, p. 270). Type species, Cytherina subradioso 

Roemer, 1838. Geologic range, Eocene to Holocene.

Cytheretta burnsi (Ulrich and Bassler)

Plate 2, figures 12-15, 16-18. plate 8, figures lla-c

Cythere burnsi Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene volume, p. 103, pi. 36, figs. 34-39. 

Cytheretta burnsi (Ulrich and Bassler). Howe, 1935, Florida

Dept. Conserv., Geol. Bull. 13, p. 33, pi. 2, figs. 12-14, 17,

pi. 4, figs. 14, 21; Malkin, 1153, Jour. Paleontology, v.

27, p. 789, pi. 81, figs. 7, 8, 10, 11; Puri, 1952, Jour.

Paleontology, v. 26, p. 205, pi. 39, figs. 5, 6; Puri, 1954,

2 Of former usage.
24 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Florida Geol. Survey Bull. 36, p. 282, pi. 7, figs. 1, 2;

McLean, 1957, Bulls. Am. Paleontology, v. 38, no. 167,

p. 91, pi. 12, figs. la-d. 

Cythere nitidula Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene volume, p. 107, pi. 36, figs. 21-28 (juv.

fide Malkin, 1953). 

Cythere nitidula var. calvertensis Ulrich and Bassler, 1904,

Maryland Geol. Survey, Miocene, volume, p. 108, pi.

36, figs. 24, 25 (juv. fide Malkin. 1953). 

Cythere paucipunctata Ulrich and Bassler, 1904, Maryland

Geol. Survey Miocene volume, p. 105, pi. 38, figs. 7-9

(female? fide Malkin, 1953).

Remarks. The zone of concrescence is broad, 

especially anteriorly, and the vestibule is developed 

only posteriorly where line of concrescence is strongly scalloped; radial canals numerous and closely 

spaced.

Occurrence. In the present collections the species was found in the middle part of the Yorktown 

Formation and in beds of Pliocene (?) age. It was 

previously reported from the Choptank and Calvert 

Formations of the Chesapeake Group of Maryland 

and Virginia (Ulrich and Bassler, 1904), from the 

upper Calvert, Choptank, and Yorktown Formations 

of Maryland and Virginia and the Kirkwood Formation of New Jersey (Malkin, 1953), and from the 

Yorktown Formation of Virginia (McLean, 1957). 

The present writer is unable to verify its occurrence 

other than in the Yorktown Formation and in beds 

of Pliocene (?) age.

Number of specimens studied. 25 + .

Ecology. The species is considered by the writer 

to have inhabited an open marine shelf at sublittoral 

to neritic depths.

Zoogeographic derivation. The species represents ostracodes that today are more characteristic 

of tropical and subtropical than of boreal or arctic 

habitats, and it may have originated in the Caribbean Faunal Province.

Figured specimens. USNM 179575-179581.

Cytheretta porcella (Ulrich and Bassler)

Plate 2, figures 19, 20

Cythere plebeia Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene volume, p. 102, pi. 35, figs. 20-29. 

[Not Cythere (Bairdia) plebeia (Reuss), Jones, in 

Kirkby, I860.]

Cythere plebeia var. capax Ulrich and Bassler. 1904, Maryland Geol. Survey, Miocene volume, p. 103, pi. 35, figs. 

30-33.

Cythere plebeia var, modica Ulrich and Bassler, 1904, Maryland Geol. Survey, Miocene volume, p. 103, pi. 35 figs. 

18, 19.

Cythere porcella Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene volume, p. 106, pi. 36, figs. 26-33.

Cytheretta plebeia (as plebia) (Ulrich and Bassler). Swain, 

1948, Maryland Dept. Geology, Mines, and Water Resources Bull. 2, p. 212, pi. 14, figs. 3, 4; Malkin, 1953,

Jour. Paleontology, v. 27, p. 790, pi. 81, figs. 1-6, 9. 

Cytheretta ulrichi Puri, 1952, Jour. Paleontology, v. 26, p.

204, pi. 39, fig. 3, text figs. 5-7; McLean, 1957, Bulls.

Am. Paleontology, v. 38, no. 167, p. 92, pi. 12, figs.

3a-d. 

[not] Cytheretta porcella (Ulrich and Bassler) Swain, 1952,

U.S. Geol. Survey Prof Paper 234-A, p, 45, pi. 4, fig.

7. ( = Proteoconcha multipunctata (Edwards), fide

Plusquellec and Sandberg, 1969.) 

Cytheretta cf. C. plebeia (Ulrich and Bassler). Swain, 1952,

U.S. Geol. Survey Prof. Paper 234-A, p. 45.

The name porcella is used for this species following Puri's (1953) statement that his species name 

ulrichi should be suppressed in favor of porcella.

Occurrence. The species occurs in the present 

collections in the Calvert, St. Marys, and Yorktown 

Formations and in beds of Pliocene (?) age. It previously was obtained from the Calvert Formation of 

Maryland and from the Chesapeake Group of Virginia (Ulrich and Bassler, 1904) and from the Yorktown Formation of Virginia and Maryland (McLean, 

1957). It was also recorded from the Pleistocene (?) 

of North Carolina (Swain, 1952), but that occurrence may represent reworking of older material.

Number of specimens studied. Six.

Ecology. Judging from the associated species, 

such as Pterygocythereis americana (Ulrich and 

Bassler, 1904) and Actinocythereis exanthemata 

(Ulrich and Bassler, 1904), this species inhabited an 

open marine shelf at sublittoral to neritic depths.

Zoogeographic derivation. The absence of this 

and related species in the Neogene of the Caribbean 

Faunal Province suggests that its derivation was the 

Arctic or Boreal Atlantic Faunal Provinces, perhaps 

from Western Europe. Related forms such as C. 

posticalis Triebel, 1952 and C. tenuistriata (Reuss, 

1853), (see Oertli, 1956) occur in the Oligocene 

Chattian and Rupelian Stages of Switzerland.

Figured specimens. USNM 179582-179584.

Genus PROTOCYTHERETTA Puri, 1958

Protocytfieretta Puri, 1958, Gulf Coast Assoc. Geol. Socs., 

Trans., v. 8, p. 188.

A diagnosis of this genus is provided in Moore and 

others (1961, p. 273). Type species, Cythere danaiana Brady, 1869. Geologic range, Oligocene to 

Holocene.

Protocytheretta sahnii (Puri) 

Plate 2, figure 21

Cytheretta sahnii Puri, 1952, Jour. Paleontology, v. 26. p.

206 pi. 39, figs. 7, 8, text figs. 1, 2; 1954, Florida Geol.

Survey Bull. 36, p. 284, pi. 8, figs. 7, 8. 

Cytherettal sahnii Puri. Benson and Coleman, 1963, Kansas
SYSTEMATIC DESCRIPTIONS 25

Univ. Paleont. Contr., Arthropoda, Art. 2, p. 25, pi. 

5, figs. 4, 6, 8, and 12.

Protocytheretta sahnii (Puri). Puri, 1958, Gulf Coast Assoc. 

Geol. Socs. Trans., v. 8, p. 188.

Occurrence. The species was obtained from the 

upper part of the Yorktown Formation, locality H-4, 

Bertie County, N.C. It was described from the Du plin Marl, upper Miocene, of Florida and also occurs 

in the Choctawhatchee Formation (of former usage;) 

of Florida (Puri, 1952).

Number of specimens studied. One.

Ecology. The species is believed to represent £,n 

open marine shelf sublittoral habitat. It is found 

living in the eastern Gulf of Mexico (Benson ar.d 

Coleman, 1963) at depths of 20-63 feet and 36.2<i37.84 parts per mil salinity.

Zoogeographic derivation. The species seems :o 

have originated in the Caribbean Faunal Province, 

possibly from a form like Cytheretta inaequivalvis 

(Ulrich and Bassler).

Figured specimen. USNM 179585.

Family BYTHOCYTHERIDAE Sars, 1926 

Genus JONESIA Brady, 1866

Jonesia Brady, 1866, Zool. Soc. London Trans., v. 5, p. 362. 

Macrocythere Sars, 1926, An account of the Crustacea :>f

Norway, v. 9, Crustacea, pts. 13, 14, p. 240. 

Macrocytherina Coryell and Fields, 1937, Am. Mus. No>itates, no. 959, p. 16. 

Luvula Coryell and Fields, 1937, Am. Mus. Novitates, no.

959, p. 13.

A diagnosis of the shell features of this genus was 

given by Moore and others (1961, p. 268). Type spscies, Cythere simplex Norman, 1865 [not Cythere 

auriculata simplex Cornuel, 1848, = Bythocythere 

acuminata Sars, 1866]. Geologic range, Miocene 1:0 

Holocene.

Jonesia? sp.

Plate 2, figure 23

Shell elongate sublanceolate to subtrapezoidal in 

side view, highest posteromedially; dorsal margin 

convex, sloping more steeply behind than in front of 

position of greatest height; ventral margin slight.y 

concave, curving abruptly into posterior margin ar d 

projecting downward at anteroventral marginal 

bend. Valves compressed. Surface smooth.

Length of figured specimen 0.42 mm, height 0.20 

mm, convexity 0.20 mm.

Remarks. The shape and other shell features of 

this form indicate a relationship to Luvula Coryell 

and Fields of the Miocene. That genus was referred 

to Jonesia Brady by Howe (in Moore and others, 

1961), but Jonesia is more acuminate posteriorly,

and the present form is only questionably referred 

to the latter genus. Too few specimens of the present 

form are available for further taxonomic treatment.

Occurrence. The species is rare in the middle 

Yorktown Formation at locality C-l, Nansemond 

County, Va., and locality S-4, James County, Va.

Number of specimens studied. Two.

Ecology. The associated species indicate that this 

form lived in neritic open-shelf environments.

Zoogeographic derivation. A somewhat similar 

species Jonesia palmerae (Coryell and Fields, 1937) 

ogcurs in the Miocene of Florida (Puri, 1954) as 

well as in Panama, and the generic stock may have 

originated in the Caribbean Faunal Province.

Figured specimen. USNM 179586.

Family XESTOLEBERIDAE Sars, 1928 

Genus XESTOLEBERIS Sars, 1866

Xestoleberis Sars, 1866, Oversight af Norges marine 

Ostracoder, p. 66.

A summarized description of the genus was given 

by Moore and others (1961, p. 343). Type species, 

Cythere aurantia Baird, 1838. Geologic range, Cretaceous to Holocene.

Xestoleberis cf. X. aurantia (Baird)

Plate 2, figures 24, 25

Xestoleberis aurantia, (Baird). Brady, 1868, Linnean Soc. 

London Trails., v. 26, p. 437. pi. 27, figs. 34-37, pi. 39, 

fig. 6.

Occurrence. In the present collection, the species 

was obtained from beds of Pliocene (?) age, Mount 

Gould Landing locality, Bertie County, N.C. It was 

previously recorded from the Holocene of Europe, 

the North Atlantic, the Arctic Ocean, Hongkong, and 

Ceylon.

Number of specimens studied. One.

Ecology. The species represents estuarine to 

marine open shelf habitat at littoral to neritic depths 

judging from associated species. At present (Elofson, 1941), it lives in waters ranging from 0°-22°C, 

and its salinity tolerance is 3-30 parts per mil 

(Neale, 1964).

Zoogeographic derivation. The origin of this 

ubiquitous form is unknown; it has close relatives in 

the Eocene and younger Cenozoic (Neogene) deposits of France and Belgium, the Holocene of northern Europe, the Caribbean Faunal Province, and the 

Pacific coast of North America.

Figured specimen. USNM 179587.

Xestoleberis? ventrostriata Swain

Xestoleberis''. ventrostriata Swain, 1952, U.S. Geol. Survey 

Prof. Paper 234-A, p. 18, pi. 4, figs. 12, 13.
26 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Occurrence. In the present collection the species 

was obtained from beds of Pliocene (?) age at Mount 

Gould Landing and Colerain Landing localities, Bertie County, N.C.

Number of specimens studied. Three.

Ecology. The associated species suggest that this 

form inhabited an open-shelf marine environment at 

sublittoral depths.

Zoogeographic derivation. The species seems to 

have originated in the Carolinian Faunal Province.

Unfigured specimen. USNM 179729.

Family LEPTOCYTHERIDAE Hanai, 1957 

Genus LEPTOCYTHERE Sars, 1925

Leptocythere Sars, 1925, Crustacea of Norway, v. 9, pts. 9,

10, p. 172. 

Leptocythera Sars, 1925 [error], Crustacea of Norway, v.

9, pts. 9, 10, p. 171.

A recent brief description of the shell of the genus 

was given by Moore and others (1961, p. 309). Type 

species, Cythere pellucida Baird, 1850. Geologic 

range, Miocene to Recent.

Leptocythere paracastanea Swain 

Plate 4, figures 5-8; plate 9, figures 6a, b

Leptocythere paracastanea Swain, 1955 Jour. Paleontology, 

v. 29, p. 640, pi. 62, fig. 7; pi. 63, figs, la-c, text 

figures 39-5a, b. Darby, 1965, Michigan Univ., Natl. 

Sci. Found. Proj. GB-26, Rept. 2, p. 20, pi. 3, figs. 

1-10; pi. 4, figs. 1-9.

Remarks. The outline, ornamentation, and internal structures of this species seem identical with 

those given for L. paracastanea Swain, 1955, and its 

range is extended back to the upper Miocene. The 

line of concrescence is scalloped posteriorly as seen 

in transmitted light (pi. 9, figs. 6a, b.)

Occurrence. Previously the species was recorded 

living in San Antonio Bay, Tex., and near Sapelo 

Island, Ga., in brackish waters. In this collection, 

the species was obtained from the middle part of 

the Yorktown Formation, locality K-4, Dinwiddie 

County Va.

Ecology. The species lives at present in brackish 

water lagoonal and tidal marsh environments.

Zoogeographic derivation. This group of Ostracoda is widespread in modern North Atlantic brackish water habitats but its site of origin is uncertain.

Figured specimens. USNM 179593-179598.

Family LOXOCONCHIDAE Sars, 1925 

Genus CYTHEROMORPHA Hirschmann 1909

Cytheromorpha Hirschmann, 1909, Soc. Fauna Flora Fennica, Meddel., v. 35, p. 290.

The shell of the genus was described briefly by

Moore and others (1961, p. 313). Type species, C. 

albula Hirschmann, 1909 (= Cythere fuscata Brady, 

1869). Geologic range, Paleocene to Holocene.

Cytheromorpha warneri Howe and Spurgeon

Plate 2, figures 26, 27; plate 3, figure 22; plate 4, figures 

1-4; plate 8, figures 2a, b; plate 9, figure 8

Cytheromorpha warneri Howe and Spurgeon, 1935, Florida 

Dept. Conserv. Geol. Bull. 13, p. 11, pi. 2, figs. 5, 8, 9; pi. 

4, fig. 4; van den Bold, 1946, Contr. study Ostracoda, 

Amsterdam, de Bussy, p. 105; Malkin, 1953, Jour. 

Paleontology, v. 27, p. 787, pi. 80, figs. 18, 19; Puri, 

1954, Florida Geol. Survey Bull. 36, p. 277, pi. 6, figs. 5- 

7, text figs, llf, g; Puri and Hulings, 1957, Gulf Coast 

Assoc. Geol. Socs. Trans., v. 7, p. 187, fig. 11; Brown, 

1958, North Carolina Dept. Conserv. Devel. Bull. 72, p. 

67, pi. 7, fig. 9; Puri, 1960, Gulf Coast Assoc. Geol. 

Socs. Trans., v. 10, p. 114, pi. 3, figs. 11, 12, text fig. 

36; Pooser, 1965, Kansas Univ. Paleont. Contr., 

Arthropoda, Art. 8, p. 51, pi. 11, gs. 3, 5, 8, 10, 11, 13; 

Hall, 1965, Michigan Univ. Nat. Sci. Found. Proj. 

GB-26, Rept. 4, p. 51, pi. 20, figs. 16-25.

Cytheromorpha cf. C. warneri Howe and Spurgeon. Swain, 

1952, U.S. Geol. Survey Prof. Paper 234-A, p. 49, pi. 

7, figs. 14, 19; McLean, 1957, Bulls. Am. Paleontology, 

v. 38, p. 70, pi. 7, figs. 3a, b.

Remarks. This species is very similar to C. 

apheles van den Bold, 1963 from the Morne 1'Enfer 

and Springvale Formations, upper Miocene, of 

Trinidad. That species, according to van den Bold 

(1963), is smaller than C. warneri and has a more 

carinate marginal rim anteriorly.

Occurrence. In the collections studied, the species is most characteristic of the Yorktown Formation but ranges downward to the St. Marys and Calvert Formations where it is generally rare (also see 

Hazel, 1971). It was not noted in the Choptank 

collections. It was previously recorded from the 

Choctawhatchee Formation (of former usage) of 

Florida (Howe and others, 1935; Puri, 1954), the 

Calvert and Yorktown Formations of the Middle 

Atlantic region (Malkin, 1953; McLean, 1957), the 

upper Miocene of North Carolina (Swain, 1952), the 

Miocene of Cuba (van den Bold, 1946), and the Holocene of the Gulf of Mexico and Pamlico Sound (Puri 

and Hulings, 1957; Puri, 1960; Benda and Puri, 

1962; Grossman, 1964; Hulings and Puri, 1964).

Number of specimens studied. 50 +.

Ecology. The species is typical of oligohaline 

lagoonal and estuarine environments.

Zoogeographic derivation. The species is apparently native to the Carolinian and Caribbean Faunal 

Provinces. It does not extend into the more northerly provinces.

Figured specimens. USNM 179574, 179588- 

179592.
SYSTEMATIC DESCRIPTIONS 27

Genus LOXOCONCHA Sars, 1866 

Loxoconcha Sars, 1866, Oversigt af Norges Marine Ostracoder (1965), p. 61. 

Loxoleberis Sars, 1866, Oversigt af Norges Marine Ostracoder (1865),p. 130 (error). 

Normania Brady, 1866, Zool. Soc. London Trans., v. 5, p.

832 [not Bowerbank, 1869; or Boeck, 1871].

The shell features of the genus are diagnosed in 

Moore and others (1961, p. 313). Type species, Cythere impressa Baird, 1850 (= C. rhomboic'ea 

Fischer, 1855). Geologic range, Cretaceous to 

Holocene.

Loxoconcha sp.

Plate 4, figure 9; plate 9, figure 7

Shell subquadrate in side view, highest poste::omedially; dorsal margin nearly straight, anter.or 

cardinal angle somewhat more obtuse than that at 

posterior end; ventral margin slightly concave anteromedially; anterior margin broadly rounded, 

somewhat extended below; posterior margin also 

broadly rounded, extended above. Valves subequal, 

the left slightly larger than right, males moderately 

convex; females strongly convex in posterior half.

Terminal and all but incurved part of venter bears 

a narrow marginal rim and shell is compressed in 

marginal zone; general surface finely pitted, supsrimposed on which is a weakly reticulate pattern of 

low narrow ridges which in terminal and ventral 

parts of shell are strongest in a concentric pattern

Hinge of left valve gongylodont, with two small 

teeth and intervening yolk-groove at each end of 

hinge and an interterminal very weakly crenulite 

bar formed of valve edge, and dorsoadjacent narrow 

accommodation groove; adductor muscle scar a 

curved subvertical group of four closely spaced spots, 

and two more anterior spots, the upper or "frontal" 

spot is oval, the lower or "mandibular" spot is obliquely elongate or double. Two dorsal muscle spots 

the posterior of which is elongate lie just below 

dorsal margin. Inner lamellae of moderate width; 

line of concrescence most widely separated from 

inner margin anteriorly; radial canals rather few 

and widely spaced, in part with funnel-shaped inner 

ends, terminally.

Length of female shell (pi. 4, fig. 9) 0.63 mm, 

height 0.34 mm, convexity 0.33 mm.

Relationships. In its combined pitted and reticulate surface ornamentation this species is like L. 

caudata Puri, 1954 from the Ecphora facies of the 

Choctawhatchee Formation (of former usage) of 

Florida, but that form is shorter and higher and 'ias 

a posteroventral flange of the shell margin unlike 

the present species.

Occurrence. The species is rare in occurrence in 

the lower Yorktown Formation at locality A-5, 

Hertford County, N.C.; in the upper Yorktown at 

locality H-4, and in beds of Pliocene (?) age, locality G-3, Bertie County, N.C.

Number of specimens studied. Three.

Ecology. The species lived in an open marine 

shelf environment judging from associated species.

Zoogeographic derivation. This group of ostracodes occurs abundantly in the Paleogene and Neogene of the Gulf of Mexico region but also in western 

Europe. Similar forms are widespread in the Cretaceous which indicates that the group attained its 

ubiquitous shallow marine distribution in later Mesozoic time.

Figured specimens. USNM 179599-179601.

Loxocoucha purisubrhomboidea (Edwards)

Plate 4, figure 10

Loxoconcha subrhomboidea Edwards, 1944 [not Brady, 1880], 

Jour. Paleontology, v. 18, p. 527, pi. 88, figs. 28-32; 

Swain, 1952, U.S. Geol. Survey Prof. Paper 234-A, p. 

25, pi. 2, figs. 18, 19; Malkin, 1953, Jour. Paleontology, 

v. 27, p. 787.

Loxoconcha purisubrhomboidea Edwards, new name, in Puri, 

1953, Jour. Paleontology, v. 27, p. 270; Puri, 1954, Florida 

Geol. Survey Bull. 36, p. 274, pi. 10, fig. 8, text fig. lOh; 

McLean, 1957, Bulls. Am. Paleontology, v. 38, no. 167, 

p. 171, pi. 7, figs. 4a-3; Brown, 1958, North Carolina 

Dept. Conserv. Devel. Bull. 72, p. 66, pi. 6, fig. 1, Hall; 

1965, Michigan Univ. Nat. Sci. Found. Kept. GB-26, 

Kept. 41 p. 50, pi. 19, figs. 9, 10, 12, 14; Grossman and 

Benson, 1967, Kans. Univ. Paleont. Contr., Ecology, Art. 

1, p. 74, pi. 15, fig. 1, pi. 18, figs. 10, 12, 14, 15, 17; 

Swain, 1968, U.S. Geol. Survey Prof. Paper 573-D, p. 

25, pi. 3, figs. 7a-e, pi. 7, fig. 7, text figs. 21c, d.

Occurrence. In the present collections this species occurs in beds of Pliocene (?) age in the Choptank, Yorktown, Duplin, and Waccamaw Formations, but is rare and somewhat questionable below 

the Yorktown. It previously has been found in the 

Duplin Marl of North Carolina (Edwards 1944), the 

Miocene of Florida (Puri, 1954) the middle and 

upper Miocene and Pliocene of North and South 

Carolina (Swain, 1952, 1968) and the Holocene of 

the Gulf of Mexico (Hulings, 1967).

Number of specimens studied. 25 + .

Ecology. The species is characteristic of estuarine environments (Hulings, 1958) at depths ranging up to 30 meters, salinity range 16-37 percent, 

temperature range 24°-25°C on sand, silt, and clay 

bottoms.

Zoogeographic derivation. The species seems to 

have originated in the Caribbean Faunal Province. 

Similar forms occur living along the Pacific Coast
28 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

of Central America and southern North America to 

where they probably migrated in pre-Holocene time. 

Figured specimens. USNM 179603-179605.

Loxoconcha wilberti Puri

Plate 4, figure 13; plate 9, figure 15

Loxoconcha wilberti Puri, 1954, Florida Geol. Survey Bull. 

36, p. 274, pi. 10, figs. 1, 2, text figs. lOa, b; Puri and 

Hulings, 1957, Gulf Coast Assoc. Geol. Socs. Trans., 

p. 187, fig. 11; Puri, 1960, Gulf Coast Assoc. Geol. 

Socs. Trans., v. 10, p. 114, pi. 4, figs. 18, 19; Hulings, 

1966, Contr. Marine Sci., v. 12, p. 93; Swain, 1968, 

U.S. Geol. Survey Prof. Paper 573-D, p. 24, pi. 3, 

figs. 6a-c, pi. 7, fig. 6; text figs. lOa, b.

Remarks. The inner lamellae are fairly broad 

but line of concrescence and inner margin nearly 

coincide (pi. 9, fig. 15) ; radial canals few and widely 

spaced.

Occurrence. In the present collections the species 

was obtained from beds of Pliocene (?) age, locality 

G-3; from the upper part of the Yorktown Formation, locality H-l, Bertie County, N.C.; and from 

locality S-5, James County Va., middle Yorktown 

Formation. It was previously recorded from the 

Choctawhatchee Formation (of former usage), upper Miocene, of Florida (Puri, 1954), the Waccamaw Formation, Pliocene, of North Carolina 

(Swain, 1968) and in living collections in the Gulf 

of Mexico (Puri and Hulings, 1957; Puri, 1960; 

Hulings, 1966).

Number of specimens studied. Four.

Ecology. The species was found in Holocene carbonate beach sands in southern and western Florida 

and presumably is a eulittoral species.

Zoo geographic derivation. This species of Loxoconcha seems to have originated in the Carolinian 

Faunal Province in the Late Miocene and to have 

spread into the Caribbean Faunal Province by Holocene time.

Figured specimens. USNM 179606-179607.

Loxoconcha reticularis (Edwards)

Plate 4, figures 11, 12

Loxoconcha reticularis Edwards, 1944, Jour. Paleontology, 

v. 18, p. 527, pi. 88, figs. 26, 27; Puri, 1954, Florida 

Geol. Survey Bull. 36, p. 274, pi. 10, fig. 7, text fig. lOe; 

Malkin, 1953, Jour. Paleontology, v. 27, p. 786, pi. 80, 

figs. 13-19; McLean, 1957, Bulls. Am. Paleontology, v. 

38, no. 167, p. 72, pi. 7, figs. 5a, b; Brown, 1958, North 

Carolina Conserv. Devel. Bull. 72, p. 66, pi. 6, fig. 2; 

Hall, 1965, Michigan Univ. Nat. Sci. Found. Proj. 

GB-26, Rept. 3, p. 51, pi. 19, figs. 1-5; Grossman and 

Benson, 1967, Kansas, Univ. Paleont. Contr., Ecology, 

Art 1, p. 75, pi. 15, fig. 2, pi. 18, figs. 2, 3; Swain,

1968, U.S. Geol. Survey Prof. Paper 573-D, p. 25. pi. 

4, figs. 2a-f, 3, text fig. 22.

Loxoconcha cf. L. retiddaris Edwards. Swain, 1952, U.S. 

Geol. Survey Prof. Paper 234-A, p. 26.

Occurrence. In the collections studied here the 

species was common in the middle part of the Calvert Formation at Gibson's locality PPN-1 (lowest 

of four samples in bluff 1 mile north of Plum Point), 

Calvert County, Md.; the lower part of the Choptank 

Formation at Gibson's locality FP-3 (in bluff 0.5 of 

a mile south of Flag Pond), Calvert County, Md.; 

the upper part of the St. Marys Formation at Gibson's localities CPS-1-2 (0.25 of a mile southeast of 

Chancellor Point), St. Marys County, Md.; the 

lower part of the Yorktown Formation, locality B-2, 

Hertford County, N.C., and locality U-l, Essex 

County, Va.; the middle part of the Yorktown Formation, localities S-3, S-4, James County, Va., and 

R-l, Isle of Wight County, Va.; Duplin Marl, at 

Natural Well, Duplin County, N.C., Lumberton, 

Robeson County, N.C. and Alien Farm, Robeson 

County, N.C. (also see Hazel, 1971). The species has 

also been found in the Waccamaw Formation, Pliocene, of North and South Carolina (Swain, 1968), 

in the subsurface upper Miocene of North Carolina 

(Swain, 1952), in the Yorktown Formation of Virginia (Malkin, 1953; McLean, 1957), in the Choctawhatchee Formation (of former usage) upper Miocene, of Florida (Puri, 1954), in the Kirkwood Formation, middle Miocene of New Jersey (Malkin, 

1953). It was also reported living by Benda and Puri 

(1962) from the eastern Gulf of Mexico.

Number of specimens studied. 25 + .

Ecology. At present (Benda and Puri, 1962) the 

species is living in the open shelf of the eastern Gulf 

of Mexico, and its fossil associations suggest that it 

typifies a sublittoral to neritic open shelf habitat.

Zoogeographic derivation. The species seems to 

have originated in the continental shelf areas of the 

southeastern United States in the early or middle 

Miocene.

Figured specimens. USNM 179608, 179609.

Family PARADOXOSTOMATIDAE Brady and Norman, 1889 

Subfamily PARADOXOSTOMATINAE Brady and Norman, 1889

Genus PARADOXOSTOMA Fischer, 1855

Paradoxostoma Fischer, 1855, Akad. Wiss. Munich, Math.- 

Phys. Kl., v. 7, p. 654.

A diagnosis of the genus was given by Moore and 

others (1961, p. 315). Type species, Paradoxostoma 

dispar Fischer, 1855. Geologic range Cretaceous (?), 

Eocene to Holocene.
SYSTEMATIC DESCRIPTIONS 29

Paradoxostoma robustum Purl

Plate 4, figures 14, 15

Paradoxostoma robusta Puri, 1954, Florida Geol. Surrey 

Bull. 36, p. 289, pi. 15, fig. 1, text figs. 12d, e.

Paradoxostoma robustum Puri. van den Bold, 1966, Koninkl. 

Nederlandse Akad. Wetensch. Verh., Afd. Natuurk. v. 

23, no. 3, p. 37.

Occurrence. The species was found to be rare in 

occurrence in the upper part of St. Marys Formation, middle Miocene and throughout the Yorktown 

Formation, upper Miocene, in the present collection. 

Puri (1954) recorded it from the lower Miocone 

Chipola Formation and the upper Miocene Choctawhatchee Formation, Ecphora Facies (of former 

usage) in Florida.

Number of specimens studied. Six.

Ecology. The species apparently can occur either 

in the euhaline inner neritic to sublittoral mar ne 

shelf environment or in mixohaline lagoonal or 

estuarine environments judged from its associated 

species.

Zoogeographic derivation. This type of Paradoxostoma may have originated in the North Atlantic Boreal Realm in some form like P. varialile 

(Baird, 1850) which is similar to, but less elongite 

than, P. robusta.

Figured specimens. USNM 179610, 179611.

Family TRACHYLEBERIDIDAE Sylvester-Bradley, 1948 

Subfamily TRACHYLEBERIDINAE Sylvester-Bradley, 1948

Genus MURRAYINA Puri, 1954

Murrayina Puri, 1954, Florida Geol. Survey Bull. 36, p. 25?.

A brief description of the shell features of :he 

genus was given by Moore and others (1961, p. 333). 

Type species, Murrayina howei Puri, 1954. Geologic 

range, Miocene.

Murrayina macleani, n. sp.

Plate 4, figures 16-21; plate 8, figures 8a-c; 

plate 9, figure 13

Diagnosis. Murrayina having elongate shell, 

weak submarginal rims and furrows, and ventnilly 

deflected narrow longitudinal ridges in posterior part 

of shell.

Description. Shell subquadrate in side viow, 

strongly dimorphic, the presumed male shells (pi. 

4, fig. 16) lower with respect to length than females 

(pi. 4, fig. 17), highest about one-fourth from anterior end; dorsal margin nearly straight to slightly 

sinuous, anterior cardinal angle more obtuse than 

posterior cardinal angle; ventral margin nearly 

straight to gently convex, converging toward posterior with respect to dorsum; anterior margin 

broadly curved, somewhat extended and bears about 

10 short spines, below; spines are backwardly curved 

in well-preserved specimens; posterior margin m ach

narrower than anterior, extended above, and has several small short spines medially. Valves of male 

shells compressed, with straightened sides as viewed 

dorsally; female valves more convex, greatest convexity posteromedian. Left valve larger than right, 

overreaching right most noticeably at cardinal 

angles.

Anterior marginal one-sixth of each valve is ornamented by two narrow ridges subparallel to margin; 

anterodorsallv is a small rounded eye tubercle; a low 

broad oblique anterodorsal sulcus-like depression defines eye tubercle behind and below; general valve 

surface bears longitudinally arranged narrow curving ridges that are bent posteroventrally in posterior 

part of shell; somewhat weaker crossbars lie between ridge and provide a reticulate ornamental pattern ; width of ridges and crossbars is one-fourth to 

one-half width of interspaces; anteromedially is a 

rounded area, which represents site of adductor 

muscle scar on valve interior; posterior sixth of 

valves smooth or with irregular continuations of 

surface ridges.

Hinge of right valve consists of an anterior high 

pointed tooth, posterojacent small socket, interterminal narrow faintly crenulate furrow, and posterior 

bluntly pointed tooth; hinge of left valve an anterior 

deep rounded socket passing downward into an ocular sinus and defined ventrally by a curving ocular 

ridge, a posterojacent tooth, interterminal weakly 

and finely notched bar and a posterior oblong socket, 

not completely enclosed ventrally.

Adductor muscle scar consists of a slightly curved, 

vertical row of four small spots and an additional 

more anterior spot. Inner lamellae of moderate 

width, having an unusual post-midventral broad 

spot; vestibule present terminally and anteromidventrally; radial canals numerous and are in part 

paired and with bulbous median expansions.

Length of holotype male left valve (pi. 4, fig. 20) 

0.78 mm, height 0.38 mm, convexity of left valve 

0.20 mm; type locality and horizon, locality P-2, 

Isle of Wight County, Va., middle Yorktown Formation.

Relationships. As compared to Murrayina howei 

Puri, 1954 this species has more evenly convex valve 

surfaces, and particularly lacks the deep furrow that 

defines the anterior marginal rim on its inner flank, 

in that species. M. gunteri (Howe and Chambers, 

1935) also has a more rugose surface than M. 

m.acleani.

Occurrence. The species was obtained from the 

middle Yorktown Formation at localities C-l and 

C-2, Nansemond County, Va., and P-2, Isle of Wight 

County, Va. It is not known to occur outside the 

Yorktown Formation, but a similar though more
30 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

elliptical form Murrayinal sp. was recorded in the 

Waccamaw Formation of North Carolina (Swain, 

1968).

Number of specimens studied. 12.

Ecology. The species represents a marine open 

shelf environment as judged from species with which 

it is associated.

Zoogeographic derivation. As nearly as can be 

determined, this form originated in the western 

North Atlantic Subtropical Realm.

Named after. James D. McLean, Jr.

Figured specimens. USNM 179612-179624.

Genus ACTINOCYTHERE1S Puri, 1953

Actinocythereis Puri, 1953, Am. Midland Naturalist, v. 49, 

p. 178.

The shell characteristics of the genus were diagnosed by Moore and others (1961, p. 334). Type species, Cythere exanthemata Ulrich and Bassler, 1904. 

Geologic range, Eocene to Holocene.

Actinocythereis exanthemata exanthemata (Ulrich and Bassler)

Plate 4, figures 23, 24; plate 5, figures 1, 2; plate 10, 

figures la-g

Cythere exanthemata Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene volume, p. 117, pi. 36, figs. 1-5.

Cythereis exanthemata (Ulrich and Bassler). van den Bold, 

1946, Contr. study Ostracoda, Amsterdam, de Bussy, 

p. 88, fig. 2; Swain, 1948, Maryland Dept. Geology, 

Mines, and Water Resources Bull. 2, p. 204, pi. 12, 

figs. 14, 15.

Cythereis exanthemata (Ulrich and Bassler) var. marylandica Howe and Hough, 1935, Florida Geol. Survey 

Bull. 13, p. 18, pi. 1, figs. 1-5, pi. 4, fig. 7.

Trachyleberis exanthemata (Ulrich and Bassler). Swain, 

1952, U.S. Geol. Survey Prof. Paper 234-A, p. 37, pi. 

6, fig. 5; Malkin, 1953, Jour. Paleontology, v. 27, p. 

791, pi. 81, figs. 16, 19, 20; van den Bold, 1964, Geos., 

no. 11, p. 8.

Actinocythereis exanthemata (Ulrich and Bassler). Puri, 

1953, Am. Midland Natuarlist, v. 49, p. 179, pi. 2, figs. 

4-8, text figs, e, f; Puri, 1954, Florida Geol. Survey 

Bull. 36, p. 252, pi. 13, figs. 6-13; McLean, 1957, Bulls. 

Am. Paleontology, v. 38, no. 167, p. 82, pi. 10, figs, lac; Brown, 1958, North Carolina Dept. Conserv. Devel. 

Bull. 72, p. 64, pi. 3, fig. 4; Hulings and Puri, 1965, 

Pub. Staz. Zool., Napoli, v. 33, p. 329, fig. 14; Grossman and Benson, 1967, Kansas Univ. Paleont. Contr., 

Ecology, Art. 1, p. 76, pi. 15, fig. 4, pi. 21, fig. 14; 

Swain, 1968, U.S. Geol. Survey Prof. Paper 573-D, p. 

14, pi. 2, figs. 5a-f, text fig. 12; Hulings, 1967, Contr. 

Marine Sci., v. 12, p. 86.

Remarks. The adductor muscle scar consists of 

four slightly raised spots (pi. 10, fig. Ig) ; "frontal" 

spot lying near dorsal end of main group also a 

raised spot. A. exanthemata marylandica (Howe and 

Hough, 1935) probably represents females of the

species as shown on plate 4, figure 23, whereas the 

males are represented by plate 4, figure 24.

Occurrence. This species was found throughout 

the Miocene in the collections studied in the lower 

part of the Calvert Formation, middle Miocene Gibson's locality PPN-4 (highest of samples in bluff, 1 

mile north of Plum Point), Calvert County, Md.; 

middle part of Calvert Formation, localities PPN-1 

(lowest of four samples) PPS-1 (lower of two samples in bluff 1 mile south of Plum Point), and PC-1 

(lowest of three samples in bluff 0.5 of a mile south 

of Parker Creek), Calvert County, Md.; lower part 

of Choptank Formation, middle Miocene, locality 

Y-l (lower of two samples in Drum Cliff near Jones 

Wharf), St. Marys County, Md. It also occurs in the 

Pungo River Formation that is exposed on the sea 

floor in Onslow Bay, Atlantic Ocean. The species was 

not found in collections from the St. Mary' Formation. In the lowest part of the Yorktown Formation, 

upper Miocene, it was found at localities A-6, B-2, 

Hertford County, N.C., and 1 mile above Seaboard Air 

Line Railroad Bridge on Meherrin River, Northampton County, N.C.; middle part of Yorktown Formation, locality C-2, D-l and D-2, Nansemond County, 

Va.; K-3, Dinwiddie County, Va., P-l, R-l, R-3 and 

R-4, Isle of Wight County, Va.; S-3 and S-4, James 

County, Va.; upper part of Yorktown Formation, localities H-l, H-2, and H-3, Bertie County, N.C.; 

Duplin Marl, upper Miocene, Barwick Farm, Duplin 

County, N.C. In the undivided Yorktown Formation 

in core hole BE-C13-63, Beaufort County, N.C., the 

species was recorded at depths of 178 feet to 185 

feet 9 inches. The species has been recorded previously from the Calvert and Choptank Formations 

of Maryland and the Chesapeake Group of Virginia 

(Ulrich and Bassler, 1964) ; the Calvert and Choptank Formations of Maryland (Malkin, 1953), but 

not the Yorktown Formation which Malkin believed 

contains A. exanthemata gomillionensis (Howe and 

Ellis, 1935) rather than A. exanthemata exanthemata (Ulrich and Bossier, 1904) ; subsurface upper 

Miocene of North Carolina (Swain, 1952) ; Chipola 

Formation, the Oak Grove Member of the Shoal 

River Formation, and Choctawhatchee Formation 

(of former usage) of Florida Panhandle area (Puri, 

1954); Waccamaw Formation of North and South 

Carolina (Swain, 1968) and Holocene of Gulf of 

Mexico (Hulings, 1967). Forms related to the species 

were reported from the Miocene Agua Clara Formation of Venezuela (van den Bold, 1964).

Number of specimens studied. 50 + .

Ecology. The species ranges in distribution from 

lagoons and bays, generally the open and lower 

parts, to the open shelf sublittoral and neritic en-
SYSTEMATIC DESCRIPTIONS 31

vironments and in a wide variety of bottom conditions.

Zoogeographic derivation, The species and genus 

evidently evolved in the marine environment off the 

southeastern United States in early Miocene time 

from the Oligocene "Trachyleberis" rosefieldensis 

Howe and Law, 1935 or similar species.

Figured specimens. USNM 179627-179631.

Actinocythereis exanthemata gomillionensis (Howe and EIHs)

Plate 4, figure 22

Cythereis exanthemata var. gomillionensis Howe and Ellis, 

1935, Florida Geol. Survey Bull. 13, p. 19, pi. 1, figs. 

6-12; pi. 4, fig. 3; Edwards, 1944, Jour. Paleontology, 

v. 18, p. 521, pi. 87, figs. 31, 32; van den Bold, 1946, 

Contr. study Ostracoda, Amsterdam, de Bussy, p. 88, 

pi. 9, fig. 19; van den Bold, 1950, Jour. Paleontology, 

v. 24, p. 83.

Actinocythereis exanthemata var. gomillionensis (Howe and 

Ellis). Puri, 1953, Am. Midland Naturalist, v. 49, p. 

181, pi. 2, figs. 1, 2; Puri, 1954, Florida Geol. Survey 

Bull. 36, p. 253, pi. 13, figs. 16, 17.

Trachyleberis exanthemata gomillionensis (Howe and Ellis). 

Malkin, 1953, Jour. Paleontology, v. 27, p. 792, pi. 81, 

figs. 17 [not figs. 15, 18=Cletocythereis mundorffi 

(Swain)].

Actinocythereis exanthemata gomillionensis (Howe and 

Ellis). McLean, 1957, Bulls. Am. Paleontology, v. 38, 

no. 167, p. 83, pi. 10, figs. 2a-d; Hall, 1965, Michigan 

Univ. Nat. Sci. Found. Proj. GB-26, Kept. 4, p. 33, 

pi. 7, figs. 12-17.

Occurrence. The species was found in the present collection in the beds of Pliocene (?) age, locality 

G-3, Bertie County, N.C. It was described and recorded earlier from the Choctawhatchee Formation 

(of former usage) Area zone, upper Miocene, of 

Florida (Howe and others, 1935; Puri, 1953, 1954) ; 

the Duplin Marl, upper Miocene of North Carolina 

(Edwards, 1944), the Yorktown Formation, upper 

Miocene of Virginia (Malkin, 1953; McLean, 1957) 

and the Miocene of the Caribbean region (van den 

Bold, 1946).

Number of specimens studied. Four.

Ecology. The associated species suggest that this 

form lived in sublittoral to neritic open-shelf 

habitats.

Zoogeographic derivation. The species apparently originated in the southeastern United States shelf 

area in late Miocene time as an ecologic variant of 

A. exanthemata exanthemata (Ulrich and Bassler, 

1904).

Figured specimens. USNM 179632-179634.

Genus CLETOCYTHEREIS Swain 1963

Cletocythereis Swain, Jour. Paleontology, v. 37, p. 823.

A trachyleberidid genus characterized by dimorphic male shell having a posteroventral flangelike 

expansion of shell which is weaker in the relatively 

higher female shells, posterodorsal subvertical short 

ridge, reticulate and nodose surface and prominent 

anteromedian node. Type species, Cythere rastromarginata Brady, 1880. Geologic range, Pleistocene 

to Holocene.

Cletocythereis mundorffi (Swain) 

Plate 5, figures 3, 4; plate 11, figures la-d

Trachyleberis mundorffi Swain, 1952, U.S. Geol. Survey

Prof. Paper 234-A, p. 36, pi. 5, fig. 19; pi. 6, fig. 4. 

ITrachlyeberis exanthemata gomillionensis (Howe and

Ellis). Malkin, 1953, Jour. Paleontology, v. 27, p. 729,

pi. 81, figs. 15, 18 [not fig. 17]. 

Actinocythereis mundorffi (Swain). Brown, 1958, North

Carolina Dept. Conserv. Devel. Bull. 72, p. 64, pi. 2,

fig. 16; Hazel, 1967, U.S. Geol. Survey Prof. Paper

564, p. 34. 

Cletocythereis mundorffi (Swain). Swain, 1968, U.S. Geol.

Survey Prof. Paper 573-D, p. 15, pi. 2, fig. 6.

The characteristics of the present species were described previously (Swain, 1952, 1968) and are further illustrated herein.

Occurrence. In this collection the species was obtained from the lower and middle parts of the Yorktown Formation and from the Duplin Marl (also see 

Hazel, 1971). In the lower Yorktown Formation it 

was found at locality A-l, Hertford County, N.C., at 

locality Z, Hanover County, Va. and 1 mile above 

Seaboard Air Line Railroad Bridge on Meherrin 

River, Northampton County, Va. In the middle Yorktown it occurs at locality C-l, Nansemond County, 

Va., locality K-3, Dinwiddie County, Va., locality 

R-2, Isle of Wight County, Va., and locality S-2, 

James County, Va. In the Duplin Marl it was obtained at the Barwick Farm locality, Duplin County, 

N.C. It was previously recorded from the middle and 

upper Miocene, from wells in North Carolina (Swain, 

1952) and from the Waccamaw Formation of North 

Carolina, Swain, 1968).

The forms identified by Hazel (1967) as Actinocythereis daivsoni (Brady, 1870) from the Gulf of 

Maine, Vineyard Sound, Gulf of St. Lawrence, 

Browns Bank, and Atlantic Ocean Continental Shelf 

off northeastern North America, and in the Pleistocene of Maine and Quebec, and Actinocythereis vineyardensis (Cushman, 1906) from Vineyard Sound, 

Gulf of Maine, Georges Bank, and Atlantic Shelf are 

very similar to C. mundorffi mundorffi although 

somewhat less reticulate, and may be descended from 

it.

Number of specimens studied. 15.

Ecology. In its fossil associations and its relationships to modern forms this species apparently
32 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

lived in sublittoral to neritic open shelf and open bay 

habitats.

Zoogeographic derivation. This form seems to 

have originated in the North American Atlantic 

area.

Figured specimens. USNM 179635-179640.

Cletocythereis mundorffi subsp. 

Plate 5, figures 5-8

This subspecies is characterized by narrower 

median longitudinal and associated ridges on the 

shell surface than in C. mundorffi mundorffi (Swain, 

1952). Only the short, high forms, presumably females, have been found for this subspecies.

Length of figured shell 0.67 mm, height 0.43 mm, 

convexity 0.36 mm.

Occurrence. The subspecies occurs in the middle 

Yorktown Formation, locality C-l, Nansemond 

County, Va.

Number of specimens studies. Three.

Ecology. The subspecies is associated with abundant Cytheretta burnsi (Ulrich and Bassler, 1904), 

Loxoconcha purisubrhomboidea Edwards, 1953, 

Murrayina mcleani n. sp., and Muellerina micula 

(Ulrich and Bassler 1904) and other forms that 

suggest an open-shelf marine environment.

Zoogeographic derivation. This form apparently 

originated in the North American Atlantic area 

from C. mundorffi as a localized subspecies.

Figured specimens. USNM 179641-179643.

Genus COSTA Neviani 1928

Costa Neviani, 1928, Pontif. Acad. Sci., Rome, Mem. Ser.

2, v. 11, p. 72. 

Rectotrachyleberis Ruggieri, 1952, Gior. Geologia, Bologna,

Ser. 2, v. 22, p. 38.

A diagnostic description of the shell of the genus 

was given by Moore and others. (1961, p. 336). Type 

species, Cytherina edwardsi Roemer, 1838. Geologic 

range, Paleocene to Holocene.

Costa barclayi (McLean)

Plate 5, figures 9-12, plate 9, figures lOa, b, 11

Murrayina barclayi McLean, 1957, Bulls. Am. Paleontology, 

v. 38, no. 167, p. 87, pi. 11, figs. 4a-f; Pooser, 1965, 

Kansas Univ. Paleont. Contr., Arthropoda, Art. 8, p. 

60, pi. 22, figs. 4, 5, 9, 11, 12.

Remarks. The shape, hingement, general surface ornamentation of the shell, and particularly the 

longitudinal ridge downturned at the posterior end, 

relate this species to Costa Neviani, 1928 rather than 

to Murrayina Puri, 1954.

The inner lamellae are of moderate width; line of 

concrescence and inner margin separated to form 

narrow vestibule anteriorly (pi. 9, fig. 11); radial

canals numerous and closely spaced terminally, fewer 

ventrally.

Occurrence. The species is rare to frequent in 

the Yorktown Formation undivided, locality O-l3 , 

Surry County, Va.; in the middle part of the Yorktown Formation, localities C-l and D-l, Nansemond 

County, Va., and K-4, Dinwiddie County, Va. and is 

rare in beds of Pliocene (?) age, locality G-3, Bertie 

County, N.C. (also see Hazel 1971). Elsewhere the 

species has been found in the Yorktown Formation 

at Moore House Beach, Va. (McLean, 1957) and 

from the Duplin Marl near Cameron, S.C. (Pooser, 

1965).

Number of specimens studied. Ten.

Ecology. The species with which it is associated 

suggest that this form inhabited littoral to sublittoral marine environments.

Zoogeographic derivation. This species seems to 

have been indigenous to the western Atlantic shelf 

area of the southeastern United States. Related species of Costa occur in the Mediterranean Sea Realm.

Figured specimens. USNM 179644-179654.

Subfamily ECHINOCYTHEREIDINAE Hazel, 1967 

Genus ECHINOCYTHEREIS Puri, 1954

Echinocythereis Puri, 1954, Florida Geol. Survey Bull. 36, 

p. 259.

The shell characteristics of the genus were diagnosed by Moore and others (1961, p. 336). The appendages were discussed by Hazel (1967) from the 

viewpoint of their relationships to both the Hemicytheridae and the Trachyleberididae. Type species, 

Cythereis garretti Howe and McGuirt, 1935. Geologic range, Upper Cretaceous to Holocene.

Echinocythereis? clarkana (Ulrich and Bassler)

Plate 5, figures 13-15 

Cythere clarkana Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene volume, p. 98, pi. 35, figs. 1-10. 

Cythere calverti Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene volume, p. 100, pi. 38, figs. 11-13. 

Cythere clarkana var. miniscula Ulrich and Bassler, 1904,

Maryland Geol. Survey, Miocene, volume, p. 99, pi. 35,

figs. 11-14. 

Leguminocythereis clarkana (Ulrich and Bassler). Swain,

1948, Maryland Dept. Geol., Mines, and Water Resources

Bull. 2, p. 207, pi. 14, fig. 6; 1952, U.S. Geol. Survey

Prof. Paper 234-A, p. 43, pi. 6, fig. 18. 

Trachyleberis clarkana (Ulrich and Bassler). Malkin, 1953,

Jour. Paleontology, v. 27, p. 792, pi. 82, figs. 1-3. 

Echinocythereis clarkana (Ulrich and Bassler). McLean,

1957, Bulls. Am. Paleontology, v. 38. p. 57-103; Pooser,

1965, Kansas Univ. Paleont. Contr., Arthropoda, Art.

8, p. 58, pi. 22, figs. 1, 6-8, 10.

Remarks. Echinocythereis 1! ligula (Lienenklaus, 

1897) as illustrated by Oertli (1956) from the Ru3 Near Cobban wharf.
SYSTEMATIC DESCRIPTIONS 33

pelian Stage (Oligocene) of Switzerland is similar 

to E. ? clarkana but is somewhat more spinose.

Occurrence. The species is rare in the present 

collection at locality U-l, Essex County, Va., locality 

A-l, Hertford County, N.C., and localities M-2 and 

M-3, Surry County, Va., lower Yorktown; and at localities S-l, James County, Va. and C-2, Nansemond 

County, Va., middle Yorktown. It was also found in 

the Calvert Formation, but not in the overlying 

Choptank and St. Marys Formations in the present 

collection. It was described originally from the Calvert Formation of Maryland (Ulrich and Bassler, 

1904) and has since been recorded from the Calvert 

Formation, subsurface, of Maryland (Swain, 1948), 

the Calvert and Kirkwood Formations of Maryland 

(Malkin, 1953), the lower, middle, and upper Miocene, subsurface, of North Carolina (Swain, 1952), 

the pre-Yorktown Miocene of Virginia (McLean, 

1957) and the Cooper Marl, Oligocene, of South Carolina (Pooser, 1965). The range of the species is 

known to be Oligocene to upper Miocene, middle 

Yorktown Formation, of the middle Atlantic States. 

It does not seem to range into the upper Yorktown 

or younger deposits. It has been found in offshore 

samples in the Atlantic Ocean ("Onslow Bay") 

where it occurs in the Pungo River Formation.

Number of specimens studied. Nine.

Ecology. The species lived in a nearshore littoral 

to sublittoral environment judged from associated 

species that are still living such as Aurila conradi 

(Howe and McGuirt, 1935) and Cytherura forulata, 

Edwards, 1944, and may have ranged into lowerthan-normal salinity environments (Hulings and 

Puri, 1965).

Zoogeographic derivation. The species has close 

relatives among European Oligocene Ostracoda, as 

for example E.I ligula (Lienenklaus, 1897) of the 

Rupelian of Switzerland, and may have originated 

either there or in its American area of occurrence.

Figured specimens. USNM 179655-179657.

Family CAMPYLOCYTHERIDAE Puri, 1960

In a recently published paper on the ostracode subfamily Campylocytherinae, Plusquellec and Sandberg (1969) retained Campylocythere Edwards, 

1944 and Acuticythereis Edwards, 1944 as distinct 

genera and proposed a new genus Proteoconcha. 

These three genera, probably together with Bensonocythere Hazel, 1967 are arranged by Plusquellec and 

Sandberg in the Family Hemicytheridae, Subfamily 

Campylocytherinae. The present writer believes that 

the more strongly developed "amphidont"-type hinge 

elements and the general tendency toward welldeveloped splitting of the adductor muscle scar spots

of the Hemicytheridae are features that would exclude the weaker hinged mainly unsplit-adductor 

scar Acuticythereis and Campylocytherc. Enough 

variation in appendage structures occurs in both 

hemicytherid and campylocytherid ostracodes, despite their general similarity, to discourage their 

grouping in the same family. For these reasons the 

family Campylocytheridae is retained in this paper.

Genns BENSONOCYTHERE Hazel, 1967

Bensonocythere Hazel, 1967, U.S. Geol. Survey Prof. Paper 

573-D, p. 29.

The genus was described fully by Hazel (1967). 

Type species, Leguminocythereis whitei Swain, 1952. 

Geologic range, Oligocene (?) Miocene to Holocene.

Bensonocythere whitei (Swain)

Plate 5, figures 16, 17; plate 11, figures 2a-e; plate 12,

figures la-f 

Leguminocythereis whitei Swain, 1952, U.S. Geol. Survey

Prof. Paper 234-A, p. 43, pi. 3, figs. 14, 16-18, pi. 4, fig.

1; Malkin, 1953, Jour. Paleontology, v. 27, p. 785-788,

pi. 80, figs. 7-12; Brown, 1958, North Carolina Dept.

Conserv. Devel. p. 63, pi. 6, fig. 10. 

Leguminocythereis (?) whitei Swain. McLean, 1957, Bulls.

Am. Paleontology, v. 38, no. 167, p. 80, pi. 9, figs. 4ab. 

Triginglymus whitei (Swain). Pooser, 1965, Kansas Univ.

Paleont. Contr., Arthropoda, Art. 8, p. 36, pi. 15, figs.

2, 5, 6, 8, 9; Hall, 1965, Michigan Univ. Nat. Sci.

Found. Proj. GB-26, Kept. 4, p. 37, pi. 9, figs. 11, 12, 14-

19.

Bensonocythere whitei (Swain). Hazel, 1967, U.S. Geol. Survey Prof. Paper 564, p. 27, pi. 5, figs. 2, 3, 8-10, pi.

10, figs. 1-8, pi. 11, figs. 1, 2; Swain, 1968, U.S. Geol.

Survey Prof. Paper 573-D, p. 29, pi. 5, figs. 4a, b,

text fig. 28. Valentine, 1971, U.S. Geol. Survey Prof.

Paper 683-D, pi. 1, figs. 14, 19.

Remarks. The adductor muscle scar lies on the 

edge of a median pit and consists of four spots in a 

curved vertical row (pi. 12, fig. Id); each spot is 

marked by a ridge on the posterior side and a furrow on the anterior side; these features are believed 

by the writer to result from the angle at which the 

adductor muscle strands are attached to the shell, 

those along the posterior side of each bundle of muscle strands arise at an acute angle from a ridge owing to higher stress requirements whereas those 

arising at a steeper angle from the anterior side 

have lower stress requirements and originate in 

furrows.

Occurrence. The species has been obtained from 

the lower part of the Choptank Formation, middle 

Miocene, to the Holocene and is believed (Hazel, 

1967) to be still living in the Atlantic Ocean (also 

see Hazel, 1971 and Valentine, 1971). It was recorded 

doubtfully from the Oligocene, subsurface, of North
34 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Carolina (Swain, 1952), but that record is questionable.

Number of specimens studied. 25 +.

Ecology. The species inhabited an open marine 

shelf at sublittoral to neritic depths judging from 

modern representatives.

Zoogeographic derivation. These ostracodes apparently originated in the Boreal Realm in the western North Atlantic shelf area of North America.

Figured specimens. USNM 179658-179663.

Genus CAMPYLOCYTHERE Edwards, 1955

Campylocythere Edwards, 1944, Jour. Paleontology, v. 18, 

p. 154.

The shell of the genus was diagnosed by Plusquellec and Sandberg (1969). Type species, C. laeva 

Edwards, 1944. Geologic range, Miocene to Holocene.

Campylocythere laeva posteropunctata Edwards

Plate 5, figures 21-24; plate 8, figure 3

Campylocythere laeva posteropunctata Edwards, 1944, Jour. 

Paleontology, v. 18, p. 515, pi. 86, figs. 15, 16.

Remarks. The subspecies was placed in synonymy with C. laeva Edwards, 1944 by Plusquellec and 

Sandberg (1969), on the basis that all degrees of 

ornamentation occur, but their illustrations show 

only a smooth form (laeva laeva) and a coarsely and 

(or) minutely pitted punctate form (laeva posteropunctata) .

Occurrence. The subspecies is rare in the middle 

Yorktown Formation locality C-l, Nansemond 

County, Va., and in beds of Pliocene (?) age, locality 

G-3, Bertie County, N.C. It was originally described 

from the Duplin Marl, upper Miocene of North Carolina.

Number of specimens studied. Three.

Ecology. The associated species, including abundant Aurila conradi (Howe and McGuirt, 1935), 

Muellerina micula (Ulrich and Bassler, 1909), and 

Loxoconcha purisubrhomboidea (Edwards, 1952) 

suggest an open shelf sublittoral habitat.

Zoogeographic derivation. This subspecies, like 

others of the genus seems to have originated in the 

waters off southeastern North America and Gulf of 

Mexico.

Figured specimens. USNM 179663-179666.

Campylocythere laeva laeva Edwards 

Plate 5, figures 18-20; plate 6, figure 1

Campylocythere laeva Edwards, 1944, Jour. Paleontology, 

v. 18, p. 515, pi. 86, figs. 8-14. (See Plusquellec and 

Sandberg, 1969, for complete synonymy.)

Occurrence. The species has been found in the 

following samples of the present collection: beds of

Pliocene (?) age, common at locality G-3, Bertie 

County, N.C.; upper Yorktown Formation, rare at 

localities H-l, and H-2, Bertie County, N.C.; middle 

Yorktown Formation, rare at localities S-l, James 

County, Va., R-l, R-3, and R-4, Isle of Wight 

County, Va., C-l, C-2, D-l and D-2, Nansemond 

County, Va.; lower Yorktown Formation, frequent 

at locality A-5, Hertford County, N.C. (also see 

Hazel, 1971).

The species was described from the Duplin Marl, 

upper Miocene, of North Carolina (Edwards, 1944). 

It has been found also in the Yorktown Formation of 

Virginia (Malkin, 1953), in the Pliocene Waccamaw 

Formation of North and South Carolina (Swain, 

1968), in the Pleistocene of Virginia (Valentine, 

1971), and is recorded living off the west coast of 

Florida (Puri and Hulings, 1957; Puri, 1960; and 

Hulings and Puri, 1965).

Number of specimens studied. 26.

Ecology. The associated species as well as modern representatives suggest that this form inhabits 

sublittoral open-shelf habitats, typically on a clean 

sandy bottom.

Zoogeographic derivation. The species originated 

in the southeastern United States-Gulf of Mexico 

marine realm in late Miocene time.

Figured specimens. USNM 179667-179669.

Genus ACUTICYTHEREIS Edwards, 1944

Aciiticythereis Edwards, 1944, Jour. Paleontology, v. 18, p. 

519.

Shell shorter and more unequal-ended than 

Campylocythere and right valve tends to be subangulate posteriorly, internally like Campylocythere. 

Type species, A. laevissima Edwards, 1944. Geologic 

range, Miocene-Holocene. The genus is retained on 

the basis of Plusquellec and Sandberg's study 

(1969). In recent years Acuticythereis had been 

placed in synomy with Campylocythere.

Acuticythereis laevissima punctata Edwards

Plate 6, figures 2, 3

Acuticythereis laevissima punctata Edwards, 1944, Jour. 

Paleontology v. 18, p. 520, pi. 87, figs. 12, 13.

Occurrence. This subspecies was found rarely at 

locality S-3, James County, Va. in the middle Yorktown and at locality G-3, Bertie County, N.C. in beds 

of Pliocene (?) age. It was originally described from 

the lower part of the Duplin Marl at Natural Well, 

near Magnolia, N.C. (Edwards, 1944).

Number of specimens studied. Two.

Ecology. Judging from associated species, this 

form lived in sublittoral to neritic open shelf environments.
SYSTEMATIC DESCRIPTIONS 35

Zoogeographic derivation. This form is apparently indigenous to the southeastern United States 

area.

Figured specimens. USNM 179671, 179672.

Acuticythereis laevissima laevissima Edwards

Plate 6, figures 4-6; plate 8, figures 1, 5, 12

Acuticythereis laevissima Edwards, 1944, Jour. Paleontology, 

v. 18, p. 519, pi. 87, figs. 4-11. (See Plusquellec and 

Sandberg, 1969, for complete synonomy.)

Occurrence. The species was found in the present 

collection in rare occurrence in beds of Pliocene (?) 

age at locality G-3 and in the upper Yorktown Formation at localities H-l and H-2, Bertie County, 

N.C.; in rare to frequent occurrence in the middle 

Yorktown at localities S-l to S-4, James County, 

Va.; localities P-l, R-l, and R-4, Isle of Wight 

County, Va., K-3 and K-4, Dinwiddie County, Va., 

C-l, D-l, and D-2, Nansemond County Va.; and 

frequent occurrence in the lower Yorktown at the 

locality 1 mile above Seaboard Airline Railroad 

bridge on Meherrin River, Hertford County, N.C. 

The species also occurs in the upper Miocene Duplin 

Marl (Edwards, 1944) of North Carolina, the Pliocene Waccamaw Formation of North and South 

Carolina (Swain, 1968), and is living off the west 

coast of Florida (Puri, 1960; Hulings and Puri, 

1965). It was reported earlier from the Yorktown 

Formation of Virginia (Malkin, 1953; McLean, 

1957), and from the Choptank Formation of Maryland (Malkin, 1953). In the present collection it is 

rare in the upper St. Marys Formation of Maryland.

Number of specimens studied. 29.

Ecology. This subspecies is found at present in 

sublittoral shallow water environments of normal to 

slightly reduced salinity.

Zoogeographic derivation. The species originated 

in the western Atlantic or Gulf of Mexico realm of 

the southeastern United States.

Figured specimens. USNM 179673, 179674.

Acuticythereis? sp., immature

Plate 6, figure 7

Shell subreniform in side view, highest about onefourth from anterior end; dorsal margin strongly 

convex, sloping more steeply anteriorad of than posteriorad of position of greatest height; ventral margin concave anteriomedially; anterior margin 

broadly curved, extended below, posterior margin 

narrowly curved also extended below. Valves somewhat compressed, most convex medially; left valve 

slightly larger than right. Surface smooth. Internal 

shell features mostly not observed. Adductor muscle

scar consists of about four spots in an anteromedian 

vertical row.

Length of figured specimen 0.48 mm, height 0.24 

mm, convexity 0.17 mm.

Remarks. This form is more compressed and 

more reniform in outline than the mature specimens 

of Acuticythereis in the collection, but its general 

form suggests that it may represent this genus. It is 

illustrated here to show the difference in shape from 

that of mature Acuticythereis.

Occurrence. Rare in middle Yorktown Formation, locality R-2, Isle of Wight County, Va.; and in 

lower Yorktown, locality A-5, Hertford County, N.C.

Number of specimens studied. Five.

Ecology. The associated species suggest that this 

form lived in shallow sublittoral waters of normal to 

slightly reduced salinities.

Figured specimens. USNM 179675.

Family LEGUMINOCYTHEREIDIDAE Howe, 1961 

Genus PRODICTYOCYTHERE Swain, n. gen.

Diagnosis. A leguminocythereidid genus having 

a trapezoidally outlined shell, reticulate or pitted 

surface, and flattened or overhanging venter.

Description. Shell subtrapezoidal in lateral outline; hinge margin shorter than but subparallel to 

ventral margin; terminal margins extended below, 

truncate above. Surface reticulate or pitted. Left 

valve slightly larger than right; valves more or less 

compressed but venter flattened and somewhat expanded. Hinge amphidont, that of right valve consists of an anterior rounded tooth, postjacent socket 

that passes into interterminal furrow and posterior 

rounded tooth. Adductor muscle scar a vertical row 

of four spots and one or two additional, more anterior spots. Inner lamellae of moderate width and 

with narrow vestibules terminally. Radial canals 

fairly numerous and closely spaced.

Type species, P. trapezoidalis, n. sp. Geologic 

range upper Miocene.

Relationships. The genus resembles Dictyocythere Sylvester-Bradley, 1955 of the Jurassic and 

Lower Cretaceous but has a more strongly developed 

holamphidont hinge and a more uniformly convex 

surface than that genus. The hingement, musculature, and general shape of the genus suggest that it 

belongs in the Leguminocythereididae.

Prodictyocythere trapezoidalis, n. gen., n. sp.

Plate 6, figures 8-10; plate 8, figure 6

Diagnosis. Prodictyocythere having surface 

marked by a coarse pattern of reticulating ridges.

Description. Shell elongate-subtrapezoidal in outline, highest about one-fourth from anterior end;
36 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

dorsal margin nearly straight, about three-fifths of 

shell length, with obtuse cardinal angles, the anterior less so than the posterior; ventral margin 

nearly straight, converging slightly toward dorsum 

posteriorly; anterior margin extended and rounded 

below, truncate above; posterior margin narrower 

than anterior; strongly extended below, truncate 

above, and extending farther beyond end of hinge 

than anterior. Valves somewhat compressed, greatest convexity median, lateral margins straightened 

medially in edge view. Left valve slightly larger 

than right, overlapping right terminally and in cardinal areas.

Surface bears strongly reticulating ridges that are 

arranged concentrically in free-marginal zone; anteromedially is a rounded only partly ornamented 

median node; ridges and pits are of about equal 

width.

Hinge holamphidont, consisting in left valve of an 

anterior rounded deep socket, posterio-adjacent 

rounded tooth, interterminal bar slightly enlarged 

at its posterior end, and a posterior rounded socket. 

Inner lamellae of moderate width; line of concrescence and inner margin slightly separated terminally.

Length of holotype shell (pi. 6, figs. 8-10) 0.76 

mm, height 0.34 mm, convexity 0.36 mm. Type horizon and locality, middle Yorktown Formation, locality C-l, Nansemond County, Va.

Relationships. The general shape and hingement 

are similar to Dictyocythere retirugata (Jones, 

1885) of the Jurassic, but the present species is 

more evenly convex and has a more clearly holamphidont hinge than that of Dictyocythere SylvesterBradley, 1956.

Occurrence. The species is rare in the middle 

Yorktown Formation at locality C-l, Nansemond 

County, Va., and in the lower Yorktown at locality 

A-l Hertford County, N.C.

Number of specimens studied. Four.

Ecology. The species occurs with abundant 

Aurila conradi (Howe and McGuirt, 1935) and 

probably represents a shallow sublittoral marine 

shelf habitat.

Zoogeographic derivation. This form appears to 

be indigenous to the western Atlantic Ocean area of 

the southeastern North America realm.

Figured specimens. USNM 179676-179678.

Family HEMICYTHERIDAE Puri, 1953 

Subfamily HEMICYTHERINAE Puri, 1953

Genus RADIMELLA Pokorny, 1968

Radimella Pokorny, 1968, Acta Universitatus Carolinae 

Geologica, No. 4, p. 360.

Diagnosis. "Carapace rather varying in shape, 

hemicytheroid, elongate-oval or subquadrate, reticulate. Eye tubercle interrupts regular arch formed by 

anterior marginal and anterodorsal ridges, the latter of which fuses in anterodorsal region with 

frontal keel. Ventral surface bordered by ventrolateral ridge. Hinge amphidont. Right valve with 

high anterior tooth bordered dorsally by lower 

elongate step; median element consists of anterior 

socket and finely structured groove; auxiliary denticles cross the groove in front of ventrally incised 

posterior tooth. Three frontal muscle scars. Dorsomedian and ventromedian adductor scars divided. 

Lateral canals of sieve type accompanied in some 

species by simple, lateral canals visible even under 

low magnification. Vestibule inconspicuous or absent. 

Some 60 to more than 100 simple marginal pore 

canals present in front of ventral concavity. Length/ 

height ratios of males larger, their mean length 

usually smaller than that of females." (Pokorny, 

1968)

Type species. R. dictyon Pokorny, 1968.

Geologic Range. Upper Miocene to Holocene.

Radimella confragosa (Edwards) 

Plate 6, figures 11-13 '

Hcmicythere confragosa Edwards, 1944, Jour. Palentology, 

v. 18, p. 518, p. 86, figs. 23-26; Swain, 1952, U.S. Geol. 

Survey Prof. Paper, 234-A, p. 43, pi. 6, figs. 13, 14; 

Puri, 1953, Washington Acad. Sci. Jour., v. 43, p. 176, 

pi. 1, figs. 4-6; Puri, 1954, Florida Geol. Survey Bull. 

36, pi. 266, pi. 11, figs. 10a-12; van den Bold, 1958, 

Micropaleontology, v. 4, p. 71; Brown, 1958, North 

Carolina Dept. Conserv. and Devel. Bull 72, p. 66, pi. 7, 

fig. 1.

Mutilus confragosa (Edwards). Puri, 1960, Gulf Coast 

Assoc. Geol. Socs. Trans., v. 10, p. 130; Swain, 1967, 

Geol. Soc. America Mem. 101, p. 83, pi. 6, figs, la, b, 

text fig. 52a; Swain, 1968, U.S. Geol. Survey Prof. 

Paper 573-D, p. 21, pi. 4, figs. 8a-e, pi. 5, figs. 5a-c, 

pi. 7, figs. 3a-c.

Aurila confragosa (Edwards), van den Bold, 1963'b, Micropaleontology, v. 9, p. 385, pi. 8, fig. 1.

Radimella confragosa (Edwards). Pokorny, 1968, Acta Universitatus Carolinae Geologica, no. 4, p. 364; Hazel, 

1971, U.S. Geol. Survey Prof. Paper 704, p. 6.

Occurrence. In the present collection the species 

is rare in the upper Yorktown at locality H-3, and 

in the beds of Pliocene (?) age, Mount Gould Landing, Bertie County, N.C. (also see Hazel, 1971). It 

was described from the upper Miocene Duplin Marl 

of North Carolina (Edwards, 1944) and has also 

been recorded from the upper Miocene of Florida 

(Puri, 1954) and the Caribbean region (van den 

Bold, 1963), and the Pliocene Waccamaw Formation 

of South Carolina (Swain, 1968) and is living
SYSTEMATIC DESCRIPTIONS 37

off the south coast of Florida (Puri, 1960). Forms 

recorded from the Gulf of California (Swain, 1967) 

I now believe are a different species.

Number of specimens studied. 25 + .

Ecology. The species lives at present in warm 

shallow sublittoral carbonate environments in Florida.

Zoogeographic derivation. The species apparently originated in the southeastern United States-Gulf 

of Mexico region in the late Miocene. With respect 

to the genus itself, Pokorny (1969) has found 16 

Holocene species in the Galapagos Islands. He states 

that Radimella underwent strong insular radiation 

in the shallow waters around the Galapagos to which 

it probably migrated from Central America.

Figured specimens. USNM 179681, 179682.

Genus AURILA Pokorny, 1955

Auris Neviani, 1928, Pontif. Acad. Sci., Rome, Mem. Ser.

2, v. 11, p. 72 (not Spix, 1827). 

Aurila Pokorny, 1955, Acta Universitatus, Carolinae^Geologica 3, p. 17.

The shell characteristics of Aurila were summarized by Howe in Moore and others (1961, p. 302). 

Type species, Cythere convexa Baird, 1850 (= Cythere punctata Miinster, 1830). Geologic range, Oligocene to Holocene.

Aurila conradi (Howe and McGuirt) 

Plate 6; figures 14-18; plate 13, figures la-g

Hemicy'there conradi (Howe and McGuirt), 1935, Florida 

Geol. Survey Bull. 13, p. 27, pi. 3, figs. 31-34, pi. 4, 

fig. 17; Edwards 1944, Jour. Paleontology, v. 18, p. 

518, pi. 86, figs. 17, 18; Swain, 1952, U.S. Geol. Survey Prof. Paper 234-A, p. 42, pi. 6, figs. 9-12; Puri, 

1953, Washington Acad. Sci, Jour., v. 43, p. 176, pi. 2, 

figs. 1, 2; Malkin, 1953, Jour. Paleontology, v. 27, p. 

796, pi. 82, figs. 16-18; Puri, 1954, Florida Geol. Survey Bull. 36, p. 306; Swain, 1955, Jour. Paleontology, 

v. 29, p. 635, pi. 62, figs. 3a-c; Brown, 1958, North 

Carolina Dept. Conserv. Devel. Bull. 72, p. 65, pi. 6, 

fig. 17.

Aurila conradi (Howe and McGuirt). McLean, 1957, Bulls, 

Am. Paleontology, v. 38, no. 167, p. 84, pi. 11, figs. 7a, 

b; Puri, 1960, Gulf Coast Asoc. Geol. Socs. Trans., v. 

10, p. 129, pi. 3, figs. 9, 10; Hulings and Puri, 1965, 

Pub. Staz. Zool., Napoli, v. 33, supp., p. 323, fig. 12A.

Aurila conradi conradi (Howe and McGuirt). Pooser, 1965, 

Kansas Univ. Paleont. Contr. Arthropoda, Art. 8, p. 

48, pi. 17, figs. 1, 2, 12, 13; Hall, 1965, Michigan Univ. 

Nat. Sci. Found. Proj. GB-26, Rept. 4, p. 32, pi. 6, 

figs. 10-19, 23; Swain 1968, U.S. Geol. Survey Prof. 

Paper 573-D, p. 23, pi. 5, figs. 7a-i, text fig. 20.

Remarks. The elevated rounded adductor muscle 

scar has furrows around the two sets of divided

spots (pi. 13, fig. Ic); the three "frontal" scars are 

rounded and elevated and the dorsal two have furrows as illustrated.

Occurrence. The species was found in the present 

collection in the upper Yorktown, rare to frequent at 

localities H-2 and H-3, Bertie County, N.C.; rare to 

abundant in the middle Yorktown at localities S-l 

to S-5, James County, Va., P-l, P-3, R-l to R-4, 

Isle of Wight County, Va.; K-3 and K-4, Dinwiddie 

County, Va., C-l, C-2, D-l and D-2, Nansemond 

County, Va.; in the lower Yorktown, rare to common at localities A-l and B-l, Hertford County, 

N.C. and 1.5 miles upstream from Seaboard Airline 

Railroad Bridge on Meherrin River, Northampton 

County, N.C. (also see Hazel, 1971).

The species previously has been obtained from the 

upper Miocene of Florida (Howe and McGuirt, 1936; 

Puri, 1954), the upper Miocene Duplin Marl of North 

and South Carolina (Edwards, 1944, Pooser, 1965), 

the subsurface upper Miocene of North Carolina 

(Swain, 1952), the Yorktown Formation of Virginia 

(Malkin, 1953; McLean, 1957) the Pliocene Waccamaw Formation of North and South Carolina 

(Swain, 1968), and the Holocene of the Gulf of 

Mexico region (Swain, 1955; Puri, 1960; Hulings and 

Puri, 1965). Records of pre-upper Miocene subsurface occurrences in North Carolina (Swain, 1952) 

are believed by the writer to be displaced specimens.

Number of specimens studied. 100+ .

Ecology. In the Gulf of Mexico region the species 

is living in sublittoral shallow bays or nearshore 

bays where salinities may range from subnormal to 

above normal for sea water.

Zoogeographic derivation. This late Miocene species seems to have originated in the Gulf of MexicoCaribbean region but there are closely related forms 

in the Oligocene of the same area and in the Oligocene and Miocene of the Mediterranean region and 

southern Europe. Either area may have served as 

the origin of this group of species.

Figured specimens. USNM. 179684-179692.

Genus CAUDITES Coryell and Fields 1937

Caudites Coryell and Fields, 1937, Am. Mus. Novitates 959, 

p. 10.

The shell of the genus was diagnosed by Howe in 

Moore and others (1961, p. 302). Type species, C. 

medialis Coryell and Fields, 1937. Geologic range, 

Eocene to Holocene.

Caudites? sp.

Plate 6, figure 20

Cauditesl sp. Swain, 1968, U.S. Geol. Survey Prof. Paper 

573-D, p. 22, pi. 5, figs. 6a, b; pi. 6, fig. 13; pi. 7, 

figs. 8a-c.
38 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

Shell subquadrate-subreniform in side view, highest one-fourth from anterior end; cardinal angles 

broadly obtuse, not well defined; dorsal margin 

slightly convex; ventral margin concave; anterior 

margin broadly curved, extended below; posterior 

margin angulated ventromedially, prominently truncated above, more weakly truncated below. Left 

valve slightly larger than right, over-reaching right 

along terminal-dorsal slope. Valves compressed, 

greatest convexity median to posteromedian.

Free margins provided with narrow submarginal 

rim that posteriorly lies farthest from margin; a 

small oblique eye tubercle lies anterodorsally; general median surface bears several longitudinal 

wrinkle-like low ridges (especially an oblique anteroventral one) and furrows but is nearly smooth; 

posterior end compressed.

Hinge of right valve consists of an anterior high 

pointed tooth, posterojacent rounded socket, interterminal and subjacent rabbet-groove formed in 

edge of valve, and a posterior pointed tooth; inner 

lamellae are of moderate width; vestibule is present 

terminally but is narrow; radial canals are very numerous but closely spaced; there are three large 

pillars anteriorly on inner valve surface adjacent to 

inner margin; adductor muscle scar not clearly seen 

but apparently consists of a median vertical row of 

spots and two more anterior "frontal spots."

Length of figured specimen 0.47 mm, height 0.26 

mm, convexity 0.17 mm.

Relationships. This species has the general 

shape, ornamentation, and internal structures of 

Caudites but is less sharply extended posteriorly 

than are most members of that genus. Its relatively 

smooth surface and low oblique anteroventral ridge 

also help to distinguish it from other species of the 

genus.

Occurrence. The species is rare in beds of Pliocene (?) age at locality G-3, Bertie County, N.C. It 

was previously recorded in the Duplin Marl, upper 

Miocene of North Carolina, and the Pliocene Waccamaw Formation, North Carolina (Swain, 1968).

Number of specimens studied. Four.

Ecology. The associated species suggest that the 

species lived in an open shelf neritic environment.

Zoogeographic derivation. The species has several similarly appearing relatives in the southeastern 

United States, Gulf of Mexico-Caribbean region and 

apparently originated there in late Miocene time.

Figured specimen. USNM 179695.

Genns MUELLERINA Bassiouni, 1965

Muellerina Bassiouni, 1965, Dansk Geol. Foren. Medd. v. 

15, pt. 4, p. 508.

The characteristics of the genus were diagnosed 

by Bassiouni (1965, p. 509), and were discussed in 

further detail by Hazel (1967). Type species, 

Cythere latimarginata Speyer, 1863. Geologic range, 

Oligocene to Holocene.

Mueller ina micula (Ulrich and Bassler)

Plate 7, figures 1-8

Cythere micula Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene volume, p. 116, pi. 36, figs. 18-20.

Trachyleberisl martini (Ulrich and Bassler). Swain, 1952, 

U.S. Geol. Survey Prof. Paper 234-A, p. 29, pi. 3, 

figs. 8, 15.

Trachyleberis martini (Ulrich and Bassler). Malkin, 1953, 

Jour. Paleontology, v. 27, p. 793, pi. 82, figs. 6-13.

Murrayina martini (Ulrich and Bassler). Puri, 1954, 

Florida Geol. Survey Bull. 36, p. 256, pi. 12, figs. 11- 

13, text figs. 8e, f; McLean, Bulls. Am. Paleontology, 

v. 38, p. 11, figs, la-c, 2a, b, 3a-d; Brown, 1958, 

North Carolina Dept. Conserv. Devel. Bull. 72, p. 65, 

pi. 3, fig. 3; Pooser, 1965, Kansas Univ. Paleont. Contr., 

Arthropda, Art. 8, p. 60, pi. 21, figs. 3, 5, 8; Hall, 1965, 

Michigan Univ. Nat. Sci. Found. Proj. GB-26, Rept. 4, 

p. 34, pi. 9, figs. 1-10, 13.

Murrayina micula (Ulrich and Bassler), Williams, 1966, 

Kansas Univ. Paleont. Inst., Paper 11, p. 31, text figs. 

18-7, 25.

Muellerina lienenklausi (Ulrich and Bassler). Hazel, 1967, 

U.S. Geol. Survey Prof. Paper 564, p. 21, pi. 3, figs. 

3-6, 11, pi. 7, figs. 1, 4, 5, 7; Swain, 1968, U.S. Geol. 

Survey Prof. Paper 573-D, p. 16, pi. 3, figs. 2a-h, 3a, 

b, 4a, b, text fig. 15.

Remarks. The confused status of this species 

was reviewed by Hazel (1967) who concluded that 

Cythere lienenklausi Ulrich and Bassler, 1904 is the 

species to which should be referred the forms identified by Murrayina martini (Ulrich and Bassler 

1904) by authors in recent years. The present writer 

has since studied the broken left valve type specimen of lienenklausi in the U.S. National Museum 

and, while recognizing the value of Hazel's work on 

the genus, concludes that the form is too incompletely known to serve as the name for "Murrayina martini" particularly because the original illustration of 

lienenklausi matches the broken type only in a general way. The types of Cythere micula (Ulrich and 

Bassler, 1904) are represented by two immature 

left valves that to the writer are more representative of "Murrayina martini" than is the lienenklausi 

type, especially in the presence in the latter of a 

stronger ventral longitudinal ridge than occurs in 

micula. Williams (1966) has referred Holocene 

forms of this type to Murrayina micula. Muellerina 

micula seems to be the best available name for the 

forms illustrated here.

Occurrence. In the present collection the species 

is rare in the upper Yorktown Formation, localities
SYSTEMATIC DESCRIPTIONS 39

H-l and H-3, Bertie County, N.C.; rare in the middle Yorktown at localities S-l, S-3, S-4, and S-5. 

James County, Va.; P-l, P-3, R-l, R-3, and R-4, 

Isle of Wight County, Va.; K-3 and K-4, Dinwiddie 

County, Va.; and common to abundant at C-l, C-2, 

D-l, and D-2, Nansemond County, Va. In the lower 

Yorktown the species is rare to common at localities 

M-l, Surry County, Va., B-l, B-2, A-l to A-6, Hertford County, N.C. The species also ranges into the 

middle Miocene Calvert Formation and occurs in the 

upper Miocene Duplin Marl and the Pliocene Waccamaw Formation in the present collection.

Previously the species was recorded from the Calvert and Yorktown Formations of Maryland and Virginia (Ulrich and Bassler, 1904), the Yorktown, 

Choptank, Kirkwood, and Calvert Formations of 

Maryland, Virginia, and New Jersey (Malkin, 1953; 

Swain, 1948; McLean, 1957), the subsurface middle 

and upper Miocene of North Carolina (Swain, 1952), 

the upper Miocene Duplin Marl of South Carolina 

(Pooser, 1965), the upper Miocene of Florida (Puri, 

1954), the Pliocene of North and South Carolina 

(Swain, 1968), the Pleistocene of Georgia (Hall,

1965), and the Holocene of the Atlantic Ocean off 

the northern United States (Hazel, 1967; Williams,

1966). Records of pre-Miocene occurrences of the 

species in wells in North Carolina (Swain, 1952) are 

believed by the writer to be displaced specimens.

Number of specimens studied. 100+ .

Ecology. The forms identified as Muellerina lienenklausi were obtained by Hazel (1967) from the 

Gulf of Maine, Browns Bank, Georges Bank, and 

other localities on the Atlantic Ocean shelf off northeastern United States at depths ranging from 37 to 

165 meters. Those forms appear to be the same as 

the ones here referred to M. micula.

Zoogeographic derivation. The species appears 

to be of North Atlantic origin.

Figured specimens. USNM 179696-179703.

Genus ORION1NA Puri, 1954

Orionina Puri, 1954, Florida Geol. Survey Bull. 36, p. 253.

The shell characteristics of the genus were diagnosed by Howe in Moore and others (1961, n. 339), 

and the musculature and anterior internal pillars 

were discussed by van den Bold (1963) and Swain 

1968).

Howe in Moore and others (1961, p. 339) referred 

Jugosocythereis Puri (1957) to Orionina, but in the 

writer's opinion the shell structure and musculature 

of the two genera are distinct enough to require 

separation.

Type species, Cythere vaughani Ulrich and Bassler, 1904 (considered by Pooser, 1965 to be a synonym of Cythere bermudae Brady, 1880, = Cythere 

serrulata Brady, 1869, not Bosquet, 1854). Van den 

Bold (1963), however, cites the variation in the marginal zone and the more extended anterior end of 

0. serrulata as basis for keeping the two species 

separate. Geologic range, Miocene to Holocene.

Orionina vaughani (Ulrich and Bassler)

Plate 7, figure 17; plate 12, figures 2a-h

Cythere vaughani Ulrich and Bassler, 1904, Maryland Geol. 

Survey Miocene volume, p. 109, pi. 38, figs. 25-27.

Cytherds vaughani (Ulrich and Bassler). Howe and others, 

1935, Florida Geol. Survey Bull. 13, p. 25, pi. 3, figs. 24, 

25; pi. 4, fig. 13; [not Coryell and Fields, 1937, Am. 

Mus. Novitates, no. 956, p. 9, fig. lOa. = O. serrulata 

Brady; Edwards, 1944, Jour. Paleontology, v. 18, p. 522, 

pi. 87, figs. 27, 28; van den Bold, 1946, Contr. study 

Ostracoda, Amsterdam, de Bussy, p. 88, pi. 10, fig. 

1; 1950, Jour. Paleontology, v. 20, p. 83.

Trachyleberis vaughani (Ulrich and Bassler). Swain, 1952, 

U.S. Geol. Survey Prof. Paper 234-A, p. 37, pi. 6, figs. 

6, 7; Malkin, 1953, Jour. Paleontology, v. 27, p. 794, 

pi. 82, fig. 14.

Orionina vaughani (Ulrich and Bassler). Puri, 1954, Florida 

Geol. Survey Bull. 36, p. 254, pi. 12, figs. 15, 16, text 

figs. 8a-c; McLean, 1957, Bulls. Am. Paleontology, v. 

38, p. 88, pi. 11, figs. 6a, b; Brown, 1958, North Carolina Dept. Conserv. and Devel. Bull. 72, p. 64, pi. 3, fig. 

2; van den Bold, 1963a, Jour. Paleontology, v. 37, p. 44, 

pi. 4, figs. 1-6, text fig. 5, 6-8; 1963b, Micropaleontology, 

v. 9, p. 386, pi. 6, fig. 7; Swain, 1968, U.S. Geol. Survey 

Prof. Paper 573-D, p. 21, pi. 4, figs. 4a-e, text fig. 19; 

Hall, 1965, Michigan Univ., Natl. Sci. Found. Project 

GB-26, Kept. 4, p. 35, pi. 7, figs. 4, 5, 7; van den Bold, 

1965, Micropaleontology, v. 11, p. 394.

Orionina bermudae (Brady). van den Bold, 1957, Micropaleontology, v. 3, p. 242, table 1 [not pi. 1, figs. 12a, 

b,=:Orionina similis van den Bold]; 1958, Micropaleontology, v. 4, p. 403 [part] [not pi. 5, fig. 9, = Orionina 

serrulata (Brady)]; Puri and Vernon, 1959, Florida 

Geol. Survey Spec. Pub. 5, p. 151, 154, 156, 182, 197, 

406 [not p. 24:3,=Orionina bradyi, van den Bold, fide 

van den Bold, 1963]; Pooser, 1965, Kansas Univ. 

Paleont. Conti*., Arthropoda, Art. 8, p. 61, pi. 17, figs. 

3, 8, 10, 11.

Remarks. The adductor muscle scar (pi. 12, fig. 

2f) consists of two upper nearly square spots with 

submarginal furrows and a lower dorso-ventrally 

elongate spot. The three "frontal" scars (pi. 12, fig. 

2e) also have bordering or submarginal furrows.

Occurrence. The species is rare to common in the 

middle Yorktown Formation at localities S-4, James 

County, Va., P-3, R-2, R-3 and R-4, Isle of Wight 

County, Va., K-4, Dinwiddie County, Va., C-l, C-2, 

D-l, and D-2, Nansemond County, Va.; in the lower 

Yorktown it is rare to frequent 1 mile and 1.5 miles 

above Seaboard Airline Railroad Bridge on Meher-
40 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

rin River, Hertford County, N.C. (also see Hazel, 

1971). It is also rare to frequent at several localities in the Duplin Marl in the present collection.

It has been recorded previously from the Chesapeake Group of Virginia (Ulrich and Bassler, 1904), 

the lower (?) and upper Miocene and Pliocene of 

Florida (Howe and others, 1935; Puri, 1954; Puri 

and Vernon, 1959), the upper Miocene Duplin Marl 

of North Carolina (Edwards, 1944), the upper and 

middle Miocene of the North Carolina subsurface 

(Swain, 1952), the uppermost lower Miocene and 

lower upper Miocene of Trinidad, the lower and 

middle Miocene of Venezuela, the middle Miocene 

and possibly lowermost Miocene of Colombia, the 

Miocene of Guatemala, and the middle and upper 

Miocene of Cuba (van den Bold, 1963). Thus the 

species seems to have begun in early Miocene time 

in northern South America but did not inhabit the 

Middle Atlantic States region until middle Miocene 

time.

Number of specimens studied. 25 + .

Ecology. The species lives in neritic open sea and 

perhaps bay environments of normal salinity and at 

depths of 4.5 to 4.35 fathoms.

Zoogeographic derivation. The species originated in the Caribbean region evidently in the early 

Miocene and spread northward to the Gulf of 

Mexico and the western middle Atlantic region 

where it or closely related forms O. bradyi van den 

Bold, 1963 and 0. serrulata (Brady, 1869), are still 

living.

Figured specimens. USNM 179704-179707.

Subfamily THAEROCYTHERINAE Hazel, 1967 

Genns THAEROCYTHERE Hazel, 1967

Thaerocythere Hazel, 1967, U.S. Geol. Survey Prof. Paper 

564, p. 25.

A diagnosis of the genus has been provided by 

Hazel (1967, p. 25). Type species, Cythereis crenulata Sars, 1866. Geologic range, Miocene to Holocene.

Thaerocythere schmidtae (Malkin) 

Plate 6, figure 19; plate 7, figures 9-15; plate 9, figures la-d

Trachyleberis cf. T.I reesidei (Swain). Swain, 1952, U.S. 

Geol. Survey Prof. Paper 234-A, p. 30, pi. 3, fig. 13 

[not Cythereis reesidei Swain, 1948.]

Hemicythere schmidtae Malkin, 1953, Jour. Paleontology, v. 

27, p. 796, pi. 82, figs. 19-23; Brown, 1953, North Carolina Dept. Conserv. Devel. Bull. 72, p. 66, pi. 3, fig. 1.

Thaerocythere schmidtae (Malkin). Hazel, 1967, U.S. Geol. 

Survey Prof. Paper 564, p. 26.

Remarks. Inner lamellae, as seen in transmitted 

light (pi. 9, figs, la-d) of moderate width; line of 

concrescence and inner margin nearly coincide; radial canals terminally are closely spaced, in places 

occurring in pairs; along venter they are fewer in 

number.

Occurrence. In this collection the species was 

found in beds of Pliocene (?) age at locality G-3?; 

in the upper Yorktown at localities H-l to H-3, 

Bertie County, N.C. and locality E, Hertford Co., 

N.C.; in the middle Yorktown at localities S-l to 

S-5, James County, Va.; locality P-l, Isle of Wight 

County, Va.; locality R-3, Isle of Wight County, Va.; 

and in the lower Yorktown at A-l and A-6, Hertford County, N.C.; B-l, Hertford County, N.C. and 

1.5 miles above Seaboard Air Line Railroad Bridge 

on Meherrin River, Northampton County, Va. (also 

see Hazel, 1971). The species was described from the 

Yorktown Formation of Virginia (Malkin, 1953), and 

was recorded from the upper Miocene in the North 

Carolina subsurface (Swain, 1952).

Number of specimens studied. 25 + .

Ecology. The species inhabited a restricted sublittoral to open-shelf environment judging from 

associated abundant Cytherura, Aurila, and Cytheromorpha.

Zoogeographic derivation. The species is related 

to Thaerocythere angulata (Sars 1866) and T. crenulata (Sars 1865) from the North Atlantic region 

and seems to have been ancestral to one or both of 

those species.

Figured specimens. USNM 179543, 179574, 

179584, 179602, 179639, 179640, 179670, 179680, 

179709, 179710.

Thaerocythere sp.

Plate 7, figure 16

Trachyleberisl cf. T. angulata (Sars), Swain, 1952, U.S. 

Geol. Survey, Prof. Paper 234-A, p. 29, pi. 3, figs. 9-12 

[placed in Thaerocythere by Hazel (1967)].

A Thaerocythere that is characterized by a 

smoothed area anterior to median node and an irregularly punctate surface.

The shell features of this species were for the 

most part described in a preceding publication 

(Swain, 1952).

Relationships. Close relationship of the species 

to Thaerocythere angulata (Sars) is shown by its 

general almondlike outline, marginal ridges and 

median node. It differs from Sars' species in having 

a smoother area anterad of the median node, lacking 

a smooth anteromedian patch, and in having a more 

irregularly punctate general surface. The species 

lacks the regularly punctate general surface 

of T. schmidtae (Malkin 1953) with which it is 

associated.
SYSTEMATIC DESCRIPTIONS 41

Length of figured shell 0.69 mm, height 0.42 mm, 

convexity 0.35 mm.

Occurrence. The species was obtained rarely at 

localities G-3, in beds of Pliocene (?) age, Bertie 

County, N.C. and S-5, James County, Va., middle 

Yorktown. It was recorded previously from the upper Miocene of the North Carolina subsurface 

(Swain, 1952).

Number of specimens studied. Three.

Ecology. The species inhabited an open shelf 

sublittoral environment judging from associated 

forms.

Zoogeographic derivation. The form is believed 

by the writer to have originated in the North Atlantic realm.

Figured specimens. USNM 179679, 179683, 

179693.

Genus PURIANA Coryell and Fields, 1953

Favella Coryell and Fields, 1937, Am. Mus. Novitates 959,

p. 8, [not Jorgensen, 1925]. 

Puriana Coryell and Fields, by Coryell in Puri, 1953, Jour.

Paleontology, v. 27, p. 750.

A description of the shell of this genus was given 

by Swain (1968) and some of the appendages of one 

species P. pacifica Benson were described by Swain 

(1967). Type species, Favella puella Coryell and 

Fields, 1937. Geologic range, Oligocene to Holocene.

The family position of the genus was recently revised by Hazel (1967) who has placed it in the Hemicytheridae-Thaerocytherinae.

Puriana rugipunctata (Ulrich and Bassler)

Plate 7, figures 19, 20

Cythere rugipunctata Ulrich and Bassler, 1904, Maryland

Geol. Survey, Miocene volume, p. 118, pi. 30, figs. 16,

17. 

Cythereis rugipunctata (Ulrich and Bassler). Howe and

others, 1935, Florida Dept. Conserv. Geol. Bull. 13, p.

23, pi. 1, figs. 18, 20-22, pi. 4, figs. 22, 23. 

Favella rugipunctata (Ulrich and Bassler). Edwards, 1944,

Jour. Paleontology, v. 18, p. 524, pi. 88, figs. 5, 6; van

den Bold, 1946, Contr. study Ostracoda, Amsterdam,

de Bussy, p. 100, pi. 10, fig. 3; 1950, Jour. Paleontology,

v. 24, p. 86; Malkin, 1953, Jour. Paleontology, v. 27, p.

797, pi. 83, fig. 24. 

Trachyleberisl rugipunctata (Ulrich and Bassler). Swain,

1952, U.S. Geol. Survey Prof. Paper 234-A, p. 38, pi.

6, fig. 8. 

Puriana rugipunctata (Ulrich and Bassler). Puri, 1953,

Jour. Paleontology, v. 27, p. 751, 1954, Florida Geol.

Survey Bull. 36, p. 257, pi. 12, figs. 16, 19, text fig.

8h; McLean, 1957, Bulls. Am. Paleontology, v, 38, no.

167, p. 89, pi. 11, figs. 4a-d; Puri, H. S. and Hulings,

N. C., 1957, Gulf Coast Assoc. Geol Socs. Trans, v.

7, p. 174, 176, 183; Brown, 1958, North Carolina Dept.

Conserv. and Devel. Bull. 72, p. 63, pi. 4, fig. 10; Puri,

1960, Gulf Coast Asoc. Geol. Socs. Trans., v. 10, p.

126, pi. 6, fig. 18; Benson and Coleman, 1963 Kansas 

Univ. Paleont. Contr. Arthropoda, Art. 2, p. 43, pi. 

8, figs. 1, 2, text fig. 27. (not pi. 8, fig. 5=mesacostalis) ; 

van den Bold, 1963, Micropaleontology, v. 9, p. 368, 370, 

371; Pooser, 1965, Kansas Univ. Paleont. Contr., Arthropoda, Art. 8, p. 61, pi. 17, figs. 4-7, 9; Hulings and 

Puri, 1965, Pub. Staz. Zool., Napoli, v. 33, Supp., p. 

321, fig. 12; Hall, 1965, Michigan Univ. Nat. Sci. Found. 

Proj. GB-26, Kept. 4, p. 36, pi. 8, figs. 1-5, 7; Grossman and Benson, 1967 Kansas Univ. Paleont. Contr., 

Ecology, Art. 1, p. 72, pi. 14, fig. 8, pi. 21, figs. 11-13; 

Swain, 1968, U.S. Geol. Survey Prof. Paper 573-D, p. 

18, pi. 5, figs. 8a-c, pi. 7, fig. 4, text figs. 16, 17. Valentine, 1971, U.S. Geol. Survey Prof. Paper 683-D, pi. 

2, figs. 31, 36.

Carinocythereis rugipunctata (Ulrich and Bassler). 

Sylvester-Bradley, in Moore and others 1961, Treatise 

on Invertebrate Paleontology, v. Q, p. 336.

Occurrence. In the middle Yorktown Formation 

of the present collection the species is rare to common at localities P-3 and R-4, Isle of Wight County, 

Va., K-4, Dinwiddie County, Va.; C-l, C-2, D-l, and 

D-2, Nansemond County, Va.; and in the lower 

Yorktown Formation at locality A-5, Hertford 

County, N.C. (also see Hazel, 1971).

Previously the species was recorded in the upper 

Miocene Yorktown Formation of Virginia (Ulrich 

and Bassler, 1904; Malkin, 1953; McLean, 1957), the 

Duplin Marl of North and South Carolina (Edwards, 

1944; Pooser, 1965), the middle and upper Miocene, 

subsurface of North Carolina (Swain, 1952; Brown, 

1958), the middle (?) and upper Miocene of Florida 

(Howe and others, 1935; Puri, 1954), the lower to 

upper Miocene of Cuba, Guatemala, British Honduras, Trinidad (van den Bold, 1946, 1963), the 

Pliocene of North and South Carolina (Swain, 1968), 

the Pleistocene of Virginia (Valentine, 1971) and 

the Holocene of Florida (Puri, 1960; Hulings and 

Puri, 1965; Benson and Coleman, 1963), Georgia 

(Hall, 1965), and North Carolina (Grossman, 1967).

Number of specimens studied. 25 + .

Ecology. The species is living at present in Pamlico Sound and nearby Atlantic Ocean near Okracoke 

Inlet, N.C. in water 10 feet to more than 30 feet 

deep, salinity 25 to 35 parts per mil and on sand or 

silty sand substrate, associated with P. mesacostalis 

(Edwards, 1944) (Grossman, 1967). It also occurs in 

the eastern Gulf of Mexico in water 19 to 239 feet 

deep, but most commonly shallower than 50 feet and 

in water having a salinity range from 35 to 40 parts 

per mil (Benson and Coleman, 1963).

Zoogeographic derivation. The species seems to 

have originated in the Gulf of Mexico-Caribbean region or in the southeastern United States area in 

early Miocene time. Its relatives have since migrated
42 UPPER MIOCENE AND PLIOCENE (?) OSTRACODA, ATLANTIC COASTAL REGION

to the Pacific coast of central and southern North 

America where they are now living (Benson, 1959; 

Swain, 1967).

Figured specimens. USNM 179694, 179703, 

179708, 179711.

Puriana mesacostalis (Edwards)

Plate 1, figure 18

Favella mesacostalis Edwards, 1944, Jour. Paleontology, v.

18, p. 524, pi. 88, figs. 1-4; Swain, 1952, U.S. Geol.

Survey Prof. Paper 234-A, p. 41. 

Puriana rugipunctata (Ulrich and Bassler) (part). Benson

and Coleman, 1963, Kansas Univ. Paleont. Contr.,

Arthropoda, Art. 2, p. 43, pi. 8, fig. 5 [not figs. 1,

2=P. rugipunctata, fide Hall, 1965]. 

Puriana mesacostalis (Edwards). Hall, 1965, Michigan

Univ. Nat. Sci. Found. Proj. GB-26, Rept. 4, p. 37, pi. 8,

figs. 6, 8-14, 17. 

Puriana mesicostalis (Edwards). Swain, 1968 (error in

spelling), U.S. Geol. Survey Prof. Paper 573-D, p. 19,

pi. 4, fig. 13, pi. 5, fig. 13.

Occurrence. This species is rare in the middle 

Yorktown Formation, locality K-4, Dinwiddie County, Va. Hazel (1971) has recorded additional occurrences in the Yorktown Formation. It was described 

from the upper Miocene Duplin Marl of North Carolina (Edwards, 1944) and also occurs in the upper 

Miocene, subsurface of North Carolina (Swain, 

1952), the Pliocene Waccamaw Formation of South 

Carolina (Swain, 1968), and in the Holocene of 

Georgia (Hall, 1965) and Florida (Benson and Coleman, 1963).

Number of specimens studied. Five.

Ecology. The species is associated with other 

ostracodes, such as Pontocythere ashermani (Ulrich 

and Bassler, 1904) that suggest an open shelf neritic 

habitat.

Zoogeographic derivation. This form apparently 

evolved from P. rugipunctata which had its origin in 

the southeastern United States-Gulf of Mexico region in late Miocene time.

Figured specimens. USNM 179712.

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INDEX

[Italic 

Page

Actinocythereis ------------------------ 30

dawsoni ------------------- ______ 31

exanthemata ----------- -- 6,18,24.30

exanthemata __-_ 4, 30, 31; pis. 4, 5, 10 

gomittionensis ______ 4, 8, 30, Si; pi. 4

vineyardensis _______ ______________ 31

acuminata, Bythocythere ________________ 25

Acuticythereis - ___ ____________ 33, 34, 35

laevissima ------------------------ 4, 35

laevissima ____ _._. ___ 35; pis. 6, 8

punctata ___.___ 4, 5, 34; pi. 6

sp ___________________ 4, 35; pi. 6

Aglaia ______ _ _____________________ 11

pulchella ______________----_-__----_ 11

Aglaiocypris -_ ______ 11

complanata ___ _ _ ___-___-___-_ 11 

virgenensis ____ __________________ 11

sp ______________ 4, 6, 7, 8, 11; pi. 1 

Aglaja ______________ _ ____________ 11

agricola, Cushmanidea _________________ 4, 8

agricola, Pontocythere -------------- 17

duopunctata, Pontocythere ---------- 9

Pemtocj/.Tiere

(Hulingsina) ____ 4, 8, J7; pis. 1, 2

Pontocythere _____________________ 17

agricola __--__________________ 17

(Hulingsina) _______ __________ 8

alaris, Cythereis __________--_---. 6, 7, 23

albomaculata, Heterocythereis ----------- 10

albula, Cytheromorpha _________________ 26

altila, Paracytheridea ---------- 4, 7, 20; pi. 1

americana, Cythereis cornuta ._________ 6, 23

Cythereis (Pterygocythereis) cornuta 23

Pterygocythereis ____ 4, 5, 7, 9, 23, 24;

pis. 2, 9, 13

cornuta ______________________ 23

angulata, Thaerocythere ________________ 40

Trachyleberis _____________________ 40

Anomocytheridea floridana -------------- 7, 8

apheles, Cytheromorpha ________________ 26

Area facies _________________11,15,21

Area Zone __________________________ 15, 31

ashermani, Cushmanidea ________________ 16

Cytherideis _______--_-____.__ 6, 16

Hulingsina .-.__ ___--_--_____-_._ 16

Pontocythere ________ 7, 8, 16, 17, 42

(Hulingsina) _.___-_ 4, 16, pis. 1, 2, 9

aurantia, Cythere ---------------------- 25

Xestoleberis __________ _3, 4, 25; pi. 2 

auricuiata simplex, Cythere _____________ 25

Aurila _________________________ 37, 40

confragosa _________________________ 36

conradi _____ 4,7,8,9,22,33,34,36,37;

pis. 6, 13 

conradi ___________________________ 37

Ai'ris ------------------.-- _____________ 37

Aversovalva _________________________ 19

Bairdia sp ----------------------------- 7

(Bairdia) plebeia, Cythere __-____---____ 24

Bairdiidae _____________-__--______ 12

page numbers indicate both major references and descriptions]

Page

Bairdoppilata ----------- __________ -2

martyni -------------- __._____---__- 12

triangulata __--------- __ 4, 5, 12; pi. 1

barclayi, Costa ____-_ 4, 5, 7, 18, 32; pis. 5, 9 

Murrayina ---------------------- ___ 32

bassleri, Haplocytheridea _______________ 9, 12

Basslerites miocenicus __________________ 9

Bensonocythere ------------------------- S3

whitei ________________ 4, 33; pis. 5, 11, 12

bermudae, Cythere ---------------------- 39

Orionina _ _____-____----____ 39

bovettensis, Cytheropteron -------------- 20

Brachycytheridae -__-____ ____________ 22

Brachycytherinae ______________--____ 22

bradyi, Cytheridea (Haplocytheridea) ____ 13

Haplocytheridea _________ 4, 8, 13; pis. 1, 8

Orionina ___________________ 39,40

burnsi, Cythere ------------------------- 6

Haplocytheridea ________ 4, 8, 13;, pis. 1, 8

Bythocypris howei ____________________ 11

Bythocythere acuminata ---------------- 25

Bythocytheridae ________________________ 25

Caloosahatehee Marl of Florida _._---_._- 13

Calvert Formation ___________3,7,10 

calvertensis, Cythere nitidula ____________ 24

calverti, Cythere ______ _______________ 32

Campylocythere _________________ 33, 34

laeva ------------------------------ 4, 34

laeva __-_______--_--___ 34; pis. 5, 6

posteropunctata _____ 4, 5, 34; pis. 5, 8

sp _____________________ 4, 5, 8, 22 

Campylocytheridae ___--_--- __________ 33

Campylocytherinae _________-__-__---_ 33

Cancettaria facies ______________________ 11

capax, Cythere plebeia ----------------- 24

Carinocythereis rugipunctata ___________ 41

caudata, Loxoconcha ___________________ 27

Caudites ------------------------------- 37

choctawhatcheensis ----------------- 4, 8

medialis ___________-_-__-_-_-___-_ 37

sellardsi __________________________ 4, 8

sp ___________________ 4, 37; pi. 6 

cellulosa, Cythere ----_--------------_-_ 20

Chipola Formation _____________________ 15

Choctawhatchee Formation ____________ 13, 15

choctawhatcheensis, Caudites ------------ 4, 8

Paracypris _---__-_---___-_---_-_-_ 7 

Choptank Formation __________________ 10

clarkana, Cythere ______________________ 6, 32

Echinocythereis ---------- 4, 6, 7, 32; pi. 5

Leguminocythereis ------------------ 32

miniscula, Cythere --------------- 6, 7, 32

Trachyleberis ----------------------- 32

Cletocythereis __________________________ 31

mundorffi _______ 4, 5, 8, 31, 32; pis. 5, 11

mundorffi ____________31,32 

Clithrocytheridea ----------------------- 15

virginiensis _-_-____-__-______--____ 7, 15

Cohansey Sand _-_-_-__---_-______-_____ 1

complanata, Aglaiocypris --------------- 11

confragosa, Aurila ______________________ 36

Hemicythere ______________________ 36

Mutilus ___________________ 36

Radimella _________ 4, 8, 9, 10, 36; pi. 6

Page

congesta, Mulinia ___ _..--- __-_ 5 

conradi, Aurila .... 4, 7, 8, 9, 22, 33, 34, 36, 37;

pis. 6, 13 

Aurila conradi --------------------- 37

conradi, Aurila ----- _____________ 37

Hemicythere ----------------------- 37

convexa, Cythere ----------------------- 37

convexum, Cytheropteron _______ ______ 19

Copytus ------------ _________________ 18

cornuta americana, Cythereis __________ 6, 23

americana, Cythereis

(Pterygocythereis) _________ 23

Pterygocythereis ------- ...__ 23

Costa ___________ 32 

barclayi __________ 4,5,7,18,32; p!s. 5,9

crenulata, Cythereis _________ 40

Thaerocythere ___ - 9, 40 

curta. Cytheromorpha _______ -__-_-_ 4, 8, S

Cushmanidea --------------------------- 15

agricola ______ _._______-_----_ __ 4, 8

ashermani -------------------------- 16

echolsae -------- _________--___-_ __ 7

fabula -- 4, 8, 15; pis. 1, 8

ulrichi -------------------- 4, 8, 16; pi. 1

Cylindms -------------------------- __-- 23

Cyprideis floridana ___ ________ 12

ovata ------------------------------ 12

Cythere aurantia ----------------------- 25

auricuiata simplex ------------------ 25

bermudae ----------- _______________ 39

burnsi ----------------------------- 6

calverti --------- ____ _________ 32

cellulosa --------------------------- 20

clarkana ---------- ____________ 6,32

miniscula ____________________ 6, 7, 32

convexa ----------- ____________ ._ 37

danaiana --------------------------- 24

declivis _______________--_-__.__--_ 15

exanthemata ----------------------- 30

fuscata -------------------- _________ 26

gibba ________-_-_--__---____-_---_ 18

impressa _____ _____ ________ 27

latimarginata _____________________ 38

latissima --------------------------- 19

lienenklausi ______________________ 7, 38

martini ___________________________ 6, 7

micula __________________________ 6, 38

muellerii __________________________ 13

nitidula __ ___ ___ _____ 24

calvertensis _-________--__-_____ 24

paucipunctata ---------- ____________ 24

pellucida __________________________ 26

planibasilis ------------------------- 6

plebeia ________ _____ __ __ 6, 7, 24

capax -------------------- ______ 24

modica -------- -_--__.__ _ 24

porcella ------------- _____________ 6, 24

punctata ---------------------- _____ 37

rastromarginata -------------------- 31

rhomboidea __--_-______-_._________ 27

rugipunctata _____________________ 6, 41

serrulata --------------------------- 39

shattucki --------------------------- 21

simplex ____________________________ 25

tuomeyi -----------------------____ 6

vaughani -------------------------- 6, 39

47
48 INDEX

Page

Cythere Continued

wetherellii __________ ___ __ 21, 22 

(Bairdia) plebeia ____--_. _._ _. 24

Cythereis alaris _-.___._____.6,7,23

cornuta americana ____________.6,23

crenulata ______________________ 40

exanthemata ___________________ 30

marylandica ._-___-__--___----__ 30

garretti __--___-- ._ ____ 32

jonesii __________________________ 22

rugipunctata ______________ _____ 41

vaughani ___________________________ 39

(Pterygocythereis) ___--_______--.___ 22

cornuta americana -___-_-__-____ 23

inexpectata ___________________ 23

Cytherelloidea leonensis _______________ 9

umbonata ________________________ 4, 7, 8

Cytheretta ____________________________ S3

burnsi ______ 4, 5, 6, 8, -3, 32; pis. 2, 8

inaequivalvis __-___--______--_____ 10, 25

plebeia _____________________ 24

porcella --_---___________ 4, 7, 24; pi. 2

posticalis _________________________ 24

sahnii ___________ _______ ________ 24

spencerensis _____________________ 10

tenuistriata -____-_-_-____________ 24

ulrichi - ____ __ _-_---._--___ 24

Cytherettidae _____________________ 23

Cytheridea --._ ___ ____-_--___--___ 13

floridana __..___________________ 12

montgomeryensis __________________ 12

muelleri _____________ 4, 5, 7, 8, 14; pi. 1

papUlosa __________________________ 10

pernota ____________________________ 15

puncticittata _______________________ 12

seminuda __-____--_-_---____-_______ 15

setipunctata ________________________ 12

(Eucytheridea) .___________________ 13

(Haplocytheridea) ___--_-_---__-____ 12

bradyi __ ________________ 13

powderosa _________---_______ 12

proboscidiala __________________ 13

wadei . ___ _____________ 13

sp. A ______________ 4, 6, 8, 13; pi. 1

sp. B _ ----- 4, 5, 7, 8, 14; pi. 1

Cytherideidae __.______________ 12

Cytherideinae ________---_--_-_---__ 12

Cytherideis _______________-____-_-_---._ 15

ashermani ----------------________ 6, 16

fabula .---____---.__________ 15

longula ___-_-_---___-_-___--______ 16

rugipustulosa _______________________ 17

semicircularis __.-_-_-_-____-__-____ 16

subulata fasciata _____--__-_____-.__ 17

ulrichi ___________________________ 16

Cytherina edwardsi ____________________ 32

subradiosa _________________________ 23

Cytheromorpha _---_----__-_-_---._-____ 40

albula .------ ___________ 26

apheles - _.______________________ 26

curta --------------------- ___ 4, 8, 9

warneri _____ 4, 9, 20, _«; pis. 2, 3, 4, 8, 9

Cytheropsis ---------------------------- 15

Cytheropteron ___--_-_-----___----_--_-_ i9

bovettensis ------------------------- 20

cowueseMm __________________________ 19

leonensis --------------------------- 22

nodoswOT ___ -------- ___ 6, 7, 20

subreticulatum -------- 4, 5, 9, 19; pis. 3, 9

talguinensis _______________________ 7

ventrokurtosa ____________________ 21

yorktownensis __.___ ---------- _ 22

(Hemicytherura) ----------- ____---_ 19

Cytherura .-.__-_____-.--- 18, 40

elongata __ . __ 4, 8, 79; pis. 3, 8, 9 

forulata ___------ 4, i«, 20, 33; pis. 2, 3

£fi&6a ________________ 3, 4, _«; pi. 3 

johnsoni ------------------------- 9

Page

Cytherura Continued

lumbertonensis -------- ._-_ 7

wardensis __________---______-_-___ 7, 8

sp _______________________ 22

Cytheruridae _________________ 18, 21

D

danaiana, Cythere ---------------------- 24

dawsoni, Actinocythereis --------------- 31

declivis, Cythere _________----______-- 15

Dentalium ___________________________ 6

depressa, Paracytheridea ---------------- 20

Dictyocythere _____-_____________ 35, 36

retirugata ------------------------- 36

dictyon, Radimella --------------------- 36

dispar, Paradoxostoma ____________ 28

duopunctata, Pontocythere agricola ______ 9

Pontocythere (Hulingsina)

agricola ___..__._ 4, 8, 17; pis. 1, 2 

Duplin Formation -__-_-_----_---------- 1,9

Duplin Marl _______________3,9,13,19 

Duplin Marl Ostracoda __ ___----__-- 8

E

Echinocythereidinae --____-_-----_--.___- 32

Echinocythereis ___________-________. 32

clarkana _.___-_---_---__ 4, 6, 7, 3%; pi. 5 

ligula --..----------- ________ 32, 33

planibasilis ------------------------- 7

echolsae, Cushmanidea __________________ 7

Ecphora facies --____-_____-_-_-___ 11, 15, 27

edivardsi, Cytherina ___________________ 32

elongata, Cytherura _______ 4, 8, 19; pis. 3, 8, 9

elongatus, Neocytherideis _______________ 17

Eocytheropteron yorktownensis ________ 21, 22

Eucythere ------------------------------ IS

triangulata --------------- 4, 5, 8, 15; pi. 1

sp _----_---______.______________ 7

(Eucytheridea), Cytheridea _____________ 13

Eucytherinae ___________-______--____ 15

evax, Henryhoivella _____________________ 15

exanthemata, Actinocythereis ____ 6, 18, 24, 3'0

Actinocythereis exanthemata ___ 4, 30, 31; 

pis. 4, 5, 10

Cythere ______--__________ 30 

Cythereis _________________- 30

exanthemata, Actinocythereis _-_4,30, 31; 

pis. 4, 5. 10 

gomillionensis,

Actinocythereis -- 4, 8, 30, SI, pi. 4 

marylandica, Cythereis _____________ 30

Trachyleberis -------- ---- ---- 30

fabula, Cushmanidea - __ 4, 8, i5; pis. 1, 8 

Cytherideis ------------------------ 15

fasciata, Cytherideis subulata ___________ 17

Favella _______________________ 41

puetta ____________-____-______._- 41

rugipunctata --------------- _______ 41

Fimbria _______________________________ 22

floridana, Anomocytheridea _____________ 7,8

Cyprideis ___ -----__---_---_ 12

Cytheridea ------------------------- 12

forulata, Cytherura _____ 4, .ZS, 20, 33; pis. 2, 3

fuscata, Cythere ------------------------ 26

garretti, Cythereis --------------------- 32

gibba, Cythere ._--_--_--_--_--_--_----_- 18

Cytherura __________.-.- 3, 4, IS; pi. 3 

gigantea, Haplocytheridea -------------- 12

gigantica, Proteoconcha ---------------- 4, 8

Glycymeris -------------- __.----__-___. 6,8

Page

gomillionensis, Actinocythereis

exanthemata -.-. 4, 8, 30, 3/; pi. 4 

gunteri, Murrayina __________________ 10, 29

H

Hemicythere strandentia ---------------- 10

Haplocytheridea ---------------------- 12, 13

bassleri __________________.- 9, 12

bradyi ___________- 4, 8, 13; pis. 1, 8 

gigantea .___ _ ______.___-___-- 12

israelskyi -------------------------- 6, 13

ponderosa -------------------------- 12

proboscidiala ----------------------- 13

setipunctata ----------------- 4, i_!; pi. 9

wadei ------------------ ____-_--_ 13

(Haplocytheridea) bradyi, Cytheridea __._ 13 

Cytheridea ---------------------- 12

ponderosa, Cytheridea _____________ 12

proboscidiala, Cytheridea ___________ 13

wadei, Cytheridea ------------------ 13

Hemicythere confragosa ________________ 36

conradi ---------------------------- 37

schmidtae --------------- ___________ 40

Hemicytheridae _________ 7, 32, 33, 36

Hemicytherinae ________________________ 36

Hemicytherideis ---------------- ________ 15

Hemicytherura ------------------------- IS

howei ____________________ 4, j20; pis. 3, 9

(Hemicytherura), Cytheropteron ________ 19

Henryhowella evax --------------------- 7, 9

Heterocythereis albomaculata ___________ 10

Holocene fauna of continental shelf ____ 10

howei, Bythocypris --------------------- 11

Hemicytherura ------------ 4, 20; pis. 3, 9

Kangarina ------------------------- 20

Murrayina ------------------------ 10, 29

Propontocypris ------------- 4, 8, 11; pi. 1

Pterygocythereis -------------------- 23

Hulingsina ---------- __________________ 16

ashermani ------------------------- 16

tuberculata ________________________ 16

(Hulingsina) agricola, Pontocythere _____ 8

agricola duopunctata,

Pontocythere _____ 4, 8, _? ; pis. 1, 2

ashermani, Pontocythere _ 4, ifi. pis. 1, 2, 9 

rugipustulosa, Pontocythere _ 4, .??"; pis. 1, 2

impressa, Cythere ______________________ 27

inaequivalvis, Cytheretta ______________ 10, 25

inexpectata, Cythereis (Pterygocythereis) 23 

Pterygocythereis ------------------ 11, 23

israelskyi, Haplocytheridea _____________ 6, 13

johnsoni, Cytherura ____________________ 9

Jonesia -------------------------------- 25

palmerae --------------------------- 25

sp __-----______--__. 4, 8, 25; pi. 2

jonesii, Cythereis ----------------------- 22

Jugosocythereis ------------------------ 39

K

Kangarina howei ---------------------- 20

karlana, Protocytheretta ________________ 9

Kirkwood Formation ___ -__ -------- 3

laeva, Campylocythere ----------------- 4, 34

Campylocythere laeva ------- 34', pis. 5, 6

laeva, Campylocythere _______ 34; pis. 5, 6

posteropunctata,

Campylocythere .. 4, 5, 34; pis. 5, 8
INDEX 49

Page

laevissima, Acuticythereis ... __ ____ 4, 35

Acuticythereis laevissima .... 35; pis. 6, 8

laevissima, Acuticythereis .... 35, pis. 6, 8

punctata, Acuticythereis ___ 4, 5, 34; pi. 6 

latimarginata, Cythere ..... __ ____ _ 38

latissima, Cythere ..._____-_------_____ 19

Leguminocythereididae _ ____ ___ 35

Leguminocythereis clarkana ____________ 32

tuomeyi .______________________ 7

Leguminocythere whitei . _______----__ 33

leonensis, Cytherelloidea . _.__________ 9

Cytheropteron ___________________ 22

Leptocythere ...--_______________ 26

paracastanea ........ 4, 5, 8, 9, 26; pi. 4, 9

Leptocytheridae _________________ 26

Leptocytheridea ...-_______ ____ 12

lienenklausi, Cythere _______________ 7, 38

Muellerina ...._______________ 38, 39

ligula, Echinocythereis .____-_--_.____ 32, 33

Localities representing middle

York town Formation _______ 5

longula, Cytherideis ___.__.-_-_____-___ 16

Lower Yorktown ostracoda 5 

Loxoconcha .. _____________________ 27

caudata .. ... ________________ 27

purisubrhomboidea ..... 4, 27, 32, 34; pi. 4

reticularis ..............____ 4, 28; pi. 4

subrhomboidea ...______________ 27

wttberti ............... 4, 5, 8, 28; pis. 4, 9

sp _______________ 4,8 8, 9, 27; pis. 4, 9 

Loxoconchidae _______.____________ 26

Loxoleberis ...._ ______.._____ 27

lumbertonensis, Cytherura .............. 7

Luvula ___________________________ 25

sp ________________ 9

M

macleani, Murrayina ...-.__ 4, 5, 8, 9, 29, 32;

pis. 4, 8, 9 

Macrocythere ____________-__________ 25

Macrocytherina .......... ____________ 25

martini, Cythere ......________________ 6, 7

Murrayina ______________________ 38

Trachyleberis ..............____._ 38

martyni, Bairdoppilata .._---___--______ 12

marylandica, Cythereis exanthemata ..._ 30 

medialis, Caudites __________________ 37

Mercenaria ___________________--___ 3, 6

mesacostalis, Puriana __ 4, 5, 8, 11, 41, 4~_ pi. 7 

micula, Cythere _______________________ 6, 38

Muellerina .......... 4, 7, 32, 34, 38; pi. 7

Murrayina ........._____________ 38

Middle Yorktown ostracoda __________. 5

miniscula, Cythere clarkana .._____ 6, 7, 32 

Miocene Ostracoda from wells in the

Atlantic Coastal Plain ____ 9 

miocenicus, Basslerites ...____-_-_____ 9

modica, Cythere plebeia .... ____________ 24

montgomeryensis, Cytheridea ...... _____ 12

Mooreina ..............._____________ 20

mucra, Paracytheridea ......... 4, 8, 20; pi. 1

muelleri, Cytheridea ______ 4, 5, 7, 8, 14; pi. 1

muellerii, Cythere ____________________ 13

Muellerina ............................ 7,38

lienenklausi ............... ______ 38, 39

micula .............. 4, 7, 32, 34, 38; pi. 7

Mulinia ............________________ 6,8

co-ngesta .................. _________ 5

multipunctata, Proteoconcha ____-__._ 4, 8, 24

mundorffi, Cletocythereis ...... 4, 5, 8, 31, 32;

pis. 5, 11 

Cletocythereis mundorffi __________ 31, 32

mundorffi, Cletocythereis .......... 31, 32

Munseyetta subminuta .................. 9

Page

Murrayina _____________________________ 29

barclayi ............................ 32

gunteri _________-..____ 10, 29

howei .............-________ 10, 29

macleani ...... 4, 5, 8, 9, 29, 32; pis. 4, 8, 9

martini ............................ 38

micula _______________________-___ 38

sp ______________________ 30 

Mutilus confragosa .....__________ _ 36

N

Neocaudites triplistriata ................ 4

triplistriatus ______ _______________ 8

Neocytherideidinae -___ _ -- 15 

Neocytherideis .....______ __ ______ 17, 18

elongatus -------------------------- 17

sp _______________ 4, 5, 8, 9, 17; pi. 3 

Nipponocythere -------------------- .. __ 21

nitidula, Cythere ....... ___ --_____ 24

calvertensis, Cythere ------______ 24

nodosa, Paracytheridea ------ ..------- 20

nodosum, Cytheropteron ........-----6,7,20

Norfolk Formation - _ 10 

Normania ...........-___-_- __-__--___ 27

O

Oak Grove Member of Shoal River

Formation ____----__-_____ 16

Orionina --------...________ ------ __ 39

bermudae ...._ __ _--_-_ 39

bradyi ...................._____ 39, 40

serrulata ________ _-__ ____ 39, 40 

similis ____________________ 39

vaughani ______ 4, 7, 8, 10, 39; pis. 7, 12 

Zone ____ -- -_ 11 

Ostracoda distribution in upper Miocene 

and Pliocene of Atlantic 

Coastal Plain __ 9 

Ostracoda from wells in the

Atlantic Coastal Plain . - 9 

Ostracoda of the Duplin Marl ________ 8

Ostracoda of the lower Yorktown _ 5 

Ostracoda of the middle Yorktown ______ 5

Ostracoda of the upper Yorktown _ 3 

Ostracoda of the Yorktown Formation _ 3 

Ostracoda from deposits of Pliocene age _ 3 

ovata, Cyprideis ___-_--______-_-______-_ 12

pacifica, Puriana .......-_-_--_ ----- 41

palmerae, Jonesia ..........____________ 25

papttlosa, Cytheridea .. ------- .-. I'D

paracastanea, Leptocythere _-__. 4, 5, 8, 9, 26;

pis. 4, 9 

Paracyprididae _ ------ --_-._. _ 11

Paracypris choctawhatcheensis ____-_._ 7

Paracytheridea _________________________ 20

altila _______________ 4, 7, 20; pi. 1 

depressa .. ._--. _____ _ 20

mucra _____ _____ __-__ 4, 8, 20; pi. 1 

nodosa, ... __ ___ ___ 20 

shattucki ........................... 21

similis ___.-____-__--- _______ --- 22

vandenboldi ................... _____ 20

wetherellii ______________________ 21

Paradoxostoma ......................... 28

dispar ............................. 28

robusta ___________________________ 9.29

robustum .................. 3, 4, 28; pi. 4

variabUe ........................... 29

Paradoxostomatidae --- 28 

Paradoxostomatinae _____ ._ 28

paucipunctata, Cythere ........ __ 24

Pectens ...________________________ 3, 6

pellucida, Cythere ....._ ____ __ 26

pernota, Cytheridea .___- --__ 15

Page

Phractocytheridea __________--_-__-_-_ 12

planibasilis, Cythere ........ ..._--_ 6

Echinocythereis ........... - 7

plebeia, Cythere - -.............. 6,7,24

capax, Cythere _-__. - 24

modica, Cythere ...-_ _ 24 

Cythere (Bairdia) .................. 24

Cytheretta ...____ 24 

Pleistocene Ostracoda of Atlantic

coastal region ----------- - 10

ponderosa, Cytheridea (Haplocytheridea) 12 

Haplocyeheridea __ _ ___ _______ 12

Pontocyprididae - --- 11 

Potnocypris trigonella ... __ _- 11 

Pontocythere ______.___-_._-- __ -- - 16

agricola ........................---- 17

agricola .................--..... 17

duopunctata .............. ______ 9

ashermani .............. 7, 8, 16, 17, 42

rugipustulosa ......... .---------- 17

subaegualis ulrichi ... _____-_____-- 7

tchernjawksii ____________-_-___-- 16

wUberti ... __ . ___ __-.-_ 17 

(Hulingsina) agricola .......________ 8

agricola duopunctata . 4, 8, 17; pis. 1, 2 

ashermani --....-.... 4, 16; pis. 1, 2, 9

rugipustulosa .......... 4, 17; pis. 1, 2

porcella, Cythere ............-...------ 6,24

Cytheretta ....._____ 4, 7, 8, 24; pi. 2

posteropunctata, Campylocythere

laeva -....._____ 4, 5, 34; pis. 5. 8

posticalis, Cytheretta'----. ... ___ 24

Prionocytheretta ..._____ __-_.--__ _ 23

proboscidiala, Haplocytheridea . .... 13

Prodictyocythere -_---_-_ 35

trapezoidalis .._-.- 4, 5, 8, 35; pis. 6, 8 

Propontocypris ....................... 11, 12

howei ...................... 4, 8, 11; pi. 1

Proteoconcha ........................... 33

gigantica ........................... 4, 8

multipunctata ................... 4, 8, 24

Protocytheretta ......................... 24

karlana ...................-........ 9

sahnii ........._ 3, 4, 8, 24; pi. 2

Pseudocytheretta ---------------------.. 23

Pterygocythereis ........................ 22

americana ..... 4, 5, 7, 9, 23, 24; pis. 2, 9, 13

cornuta americana ... ______________ 23

howei __ ............................ 23

inexpectata ....................... 11,23

Zone ___________________ 10 

(Pterygocythereis), Cythereis ............ 22

cornuta americana, Cythereis ....... 23

inexpectata, Cythereis .............. 23

Pterygocytherinae ___ .._ . 22 

puella, Favella ......................... 41

pulchella, Aglaia ....................... 11

punctata, Acuticythereis

laevissima ...__-__ 4, 5, 34; pi. 6 

Cythere ............................ 37

puncticillata, Cytheridea ................ 12

Pungo River Formation __ _-._ 3 

Puriana ................................ 41

mesacostalis ........ 4, 5, 8, 11, 41, 42; pi. 7

Zone __________________ 11 

pacifica ............................ 41

rugipunctata __________ 4, 7, 8, 41, 42; pi. 7

purisubrhomboidea,

Loxoconcha .... 4, 27, 32, 34; pi. 4

Radimetta ..... _---___________________ 36

confragosa . ......... 4, 8, 9, 10, 36; pi. 6

dictyon .......................____ 36

rastromarginata, Cythere ______________ 31

Rectotrachyleberis ..... __ _ __ 32

reesidei, Trachyleberis ...__-----__----_ 40
50 INDEX

Page

reticularis, Loxoconcha ___ __-__ 4, 28; pi. 4 

retirugata, Dictyoeythere ______________ 36

rhomboidea, Cythere ___________________ 27

robusta, Paradoxostoma ________________ 9, 29

robustum, Paradoxostoma ____.__ 3, 4, 28; pi. 4

rosefieldensis, Trachyleberis ____________ 31

rugipunctata, Carinocythereis ___-._-___ 41 

Cythere __________________ 6, 41 

Cythereis ______-----______..__ 41

Favella ... ____.______________ 41

Puriana ______________ 4, 7, 8, 41, 42; pi. 7

Trachyleberis _.___._____________ 41

rugipustulosa, Cytherideis _____________ 17

Pontocythere . ____________________ 17

(Hulingsina) ________ 4, 17; pis. 1, 2

Sacculus _______________________________ IB

Sahnia __-_----_-_-___--_______________ 17

sahnii, Cytheretta _________________ 24

Protocytheretta ______ 3, 4, 8, 24; pi. 2 

St. Marys Formation _.____-_-___-_ 3, 6, 10

schmidtae, Hemicythere ________________ 4'0

Thaerocythere ..... 4, 8, 9, 14, 40; pis. 6, 9

Trachyleberis ....................... 40

sellardsi, Caudites ........... __________ 4,8

semicircularis, Cytherideis .......... ___ 16

seminiida, Cytheridea ........_________ 16

serrulata, Cythere ______________________ 39

Orionina ......._________________ 39, 40

setipunctata, Cytheridea ................ 12

Haplocytheridea .............. 4, 12; pi. 9

shattucki, Cythere _____________________ 21

Paracytheridea ..... _______________ 21

Shattuckocy'there ... 4, 7, 8, 21, 22; pis. 1, 8 

Shattuckocythere ....................... 21

shattucki .......... 4, 7, 8,21, 22; pis. 1, 8

similis ......______ 4, 8, 9, 22; pis. 1, 9

ventrokurtosa ...................... 22

yorktownensis ----------- 4, 8, 22; pis. 3, 9

similis, Orionina _______________________ 39

Paracytheridea _______._-_-________ 22

Shattuckocythere ______ 4, 8, 9, 22; pis. 1, 9

simplex, Cythere _______--__._________ 2B

Cythere auriculata __-________--.__ 2B

spencerensis, Cytheretta -__-_--____-___ 10

strandentia, Hemicythere --------------- 10

Stratigraphic summary _________________ 1

subaequalis ulrichi, Pontocythere ________ 7

Page

subminuta, Munseyella __________________ 9

subradiosa, Cytherina _____ ____------_ 23

subreticulatum,

Cytheropteron _ 4, 5, 9, 19; pis. 3, 9 

subrhomboidea, Loxoconcha _____________ 27

subulata fasciata, Cytherideis ------------ 17

Systematic descriptions _________________ 11

talquinensis. Cytheropteron ______-_-__-_ 7

tchernjawskii, Pontocythere _____________ 16

tenuistriata, Cytheretta ----------------- 24

Thaerocythere -------------------------- 40

angulata ------------------- ______ 40

crenulata ________________ _______ 9, 40

schmidtae ....- 4, 8, 9, 14, 40; pis. 6, 9

sp _______________ 4, B, 8, 40; pi. 7 

Thaerocytherinae -__-_---_-_ ___ 40 

Trachyleberidae __________-___---__--___ 7

Trachyleberididae ____-_.-__ 22, 29, 32 

Trachyleberidinae _____-____-__.__-__-- 29

Trachyleberis angulata ------------------ 40

clarkana ____ ________________ _ 32

exanthemata _____--__-___--__ ____ 30

martini ____________________________ 38

reesidei ---------------------------- 40

rosefieldensis -------------- _______ 31

rugipunctata _______________________ 41

schmidtae -------- _-_-_____--_-- 40

vaughani _______________----------- 39

trapezoidalis, Prodictyocythere _____ 4, B, 8, 35;

pis. 6, 8 

triangulata, Bairdoppilata ______ 4, B, 12; pi. 1

Eucythere --------------- 4, B, 8, 15; pi. 1

triginglymus whitei ____________________ 33

trigonella, Pontocypris _________________ 11

triplistriata, Neocaudites _______-._-____ 4

triplistriatus, Neocaudites _______________ 8

tuberculata, Hulsingina ----------------- 16

tuomeyi, Cythere ____________----__-_-__ 6

Leguminocythereis ----------------- 7

Turritella __________________-__ 6

U

ulrichi, Cushmanidea ___________ 4, 8, iff; pi. 1

Cytheretta __.._____________ 24

Cytherideis ________________________ 16

Pontocythere subaequalis _____.----_ 7

Page 

wmbowata, Cytherelloidea _____________ 4, 7, 8

Upper Yorktown ostracoda _____________ 3

vandenboldi, Paracytheridea ------------- 20

variabUe, Paradoxostoma _____________ 29

vaughani, Cythere ------ 6, 39

Cythereis ---------- __________ 39

Orionina _______ 4, 7, 8, 10, 39; pis. 7, 12 

Trachyleberis _______________________ 39

ventrokurtosa, Cytheropteron ----------- 21

Shattuckocythere ... ________________ 22

ventrostriata, Xestoleberis ____________ 4, 8, 25

vineyardensis, Actinocythereis ----------- 31

virgenensis, Aglaiocypris -____._____-.__ 11

Clithrocytheridea ______________ 7, IB

W

Waccamaw Formation --------__ 3, 9, 13, 17

[ wadei, Cytheridea (Haplocytheridea) ___ 13 

Haplocytheridea ...-.--------------- 13

wardensis, Cytherura ___________________ 7, 8

warneri, Cytheromorpha -_-___.___ 4, 9, 20, 26;

pis. 2, 3, 4, 8, 9 

wetherellii, Cythere ---------- _____ 21, 22

Paracytheridea _____________________ 21

whitei, Bensonocythere _____ 4, 33; pis. 6, 11, 12

Leguminocythere _---_-__-_-________ 33

Triginglymus -------------- ________ 33

wilberti, Loxoconcha ______ 4, B, 8, 2S; pis. 4, 9

Pontocythere _______________ 17

Xestoleberidae __-_---_-__--__-._________ 2B

Xestoleberis ___________________________ 25

awrantia _.__ __________ 3, 4, 25; pi. 2

ventrostriata ___________________ 4, 8, 25

Yorktown Formation ______________ 1, 6, 9, 10

yorktownensis, Cytheropteron -___ 22 

Eocytheropteron __________________ 21, 22

Shattuckocythere ____-_._ 4, 8, 22; pis. 3. 9
PLATES 1-13

Contact photographs of the plates in this report are available, at cost, from U.S. 

Geological Survey Library, Federal Center, Denver, Colorado 80225.
PLATE 1

[Scanning1 electron microscope and optical microscope photographs]

FIGURE 1. Bairdoppilata triangulata Edwards (p. l?j.

Right side of shell; locality S-5, James County, Va., X 32, Yorktown Formation, middle part. 

2. Aglaiocypris sp. (p. 11).

Interior of right valve; locality U-l, Essex County, Va., X 45, Yorktown Formation, lower part. 

3,15. Propontocypris howei (Puri) (p. 11).

3. Exterior of a poorly preserved right valve; locality A-5, Hertford County, N.C., X 45, Yorktown Formation, lower part.

15. Right side of a shell, broken dorsally; locality A-5, Hertford County, N.C., X 69, Yorktown formation, lower part. 

4,11,12. Cytheridea sp. B (p. 14).

4. Interior of left valve; locality PPN-1, Plum Point, 1 mile north of, Calvert County, Md., X 37.5, 

Calvert Formation, middle Miocene.

11. Exterior of right valve; locality C-l, Nansemond County, Va., X 70.5, Yorktown Formation, 

Middle part.

12. Interior of left valve; locality C-l Nansemond County, Va., X 70.5, Yorktown Formation, Middle part. 

5. Cytheridea muelleri subsp. (p. 14).

Right side of shell; locality C-l, Nansemond County, Va., X 69, Yorktown Formation, Middle part. 

6-8. Cytheridea sp. A (p. 13).

6. Exterior of left valve; locality C-l, Nansemond County, Va., X 69, Yorktown Formation, Middle part.

7. Exterior of left valve; locality A-l, Hertford County, N.C., X 69, Yorktown Formation, lower 

part.

8. Exterior of right valve; Mount Gould Landing locality, Bertie County, N.C., X 69, Beds of Pliocene (?) age. 

9,10,13. Haplocytheridea bradyi (Stephenson) (p. 13).

Reversal of valve size and hingement is shown in these specimens.

9. Left side of shell; Mount Gould Landing locality Bertie County, N.C., X 69, beds of Pliocene (?)

age.

10. Interior of right valve; Mount Gould Landing locality, Bertie County, N.C., X 64, beds of Pliocene (?) age.

13. Interior of left valve; Mount Gould Landing locality, Bertie County, N.C., X 69, beds of Pliocene (?) age. 

14. Shattuckocythere shattucki (Ulrich and Bassler) (p. 21).

Left side of shell; locality P-l, Isle of Wight County, Va., X 75, Yorktown Formation, middle part.

16. Eucythere triangulata Puri (p. 15).

Right side of shell; locality D-l, Nansemond County, Va., X 69, Yorktown Formation, middle part.

17. Paracytheridea altila Edwards (p. 20).

Exterior of right valve; locality P-3, Isle of Wight County, Va., X 75, Yorktown Formation, middle 

part.

18. Pontocythere (Hulingsina) cf. P. (H.) rugipustulosa (Edwards) (p. 17).

Right side of shell; locality G-3, Bertie County, N.C., X 69, beds of Pliocene (?) age. 

19a, b. Shattuckocythere similis (Malkin) (p. 22).

Left side and dorsal views of a shell; Mount Gould Landing locality, Bertie County, N.C., X 75,

beds of Pliocene (?) age. 

20. Cushmanidea fabula (Howe and Dohm) (p. 15).

Right side of shell; locality N-l, Surry County, Va., X 69, Yorktown Formation, lower part. 

21,24. Pontocythere (Hulingsina) ashermani (Ulrich and Bassler) (p. 16).

21. Interior of male left valve; locality G-3, Bertie County, N.C., X 72, beds of Pliocene (?) age. 

24. Exterior of immature left valve; locality K-4, Dinwiddie County, Va., X 72, Yorktown Formation, middle part.

22. Pontocythere (Hulingsina) agricola duopunctata n. subsp. (p. 17).

Right side of paratype shell; locality C-l, Nansemond County, Va., X 36, beds of Pliocene (?) age.

23. Paracytheridea mucra Edwards (p. 20).

Right side of shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age. 

25. Cushmanidea ulrichi (Howe and Johnson) (p. 16).

Right side of shell; locality S-5, James County, Va., X 69, Yorktown Formation, middle part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 1

BAIRDOPPILATA, AGLAIOCYPRIS, PROPONTOCYPRIS, CYTHERIDEA,HAPLOCYTHERIDEA, SHATTUCKOCYTHERE, 

EUCYTHERE, PARACYTHERIDEA,PONTOCYTHERE, AND CUSHMANIDEA
PLATE 2

[Scanning electron microscope and optical microscope photographs]

FIGURES 1-3. Pontocythere (Hulingsina) ashermani (Ulrich and Bassler) (p. 16).

1. Right side of a poorly preserved male shell, locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle part.

2. Right side of a male shell; locality G-3, Bertie County, N.C., X 72, beds of Pliocene (?) age.

3. Dorsal View of female shell; locality C-l, Nansemond County, Va., X 75, Yorktown Formation,

middle part. 

4-7. Pontocythere (Hulingsina) cf. P. (H.) rugipustulosa (Edwards) (p. 17).

4. Right side of male? shell; locality K-4, Dinwiddie County, Va., X 75, Yorktown Formation, 

middle part.

5. Right side of immature shell; locality G-3, Bertie County, N.C., X 74, beds of Pliocene (?) age.

6. Right side of immature shell; locality K-4, Dinwiddie County, Va., X 72, Yorktown Formation, 

middle part.

7. Left side of immature shell; locality K-4, Dinwiddie County, Va., X 75, Yorktown Formation,

middle part. 

8 10. Pontocythere (Hulingsina) agricola duopunctata n. subsp. (p. 17).

8. Right side of holotype female? shell; locality K-4, Dinwiddie County, Va., X 72, Yorktown Formation, middle part.

9,10. Right side of two paratype male? shells locality G-3, Bertie County, N.C., X 72, beds of Pliocene (?) age. 

11. Pterygocythereis americana (Ulrich and Bassler) (p. 23).

Exterior of immature right valve; locality U-l. Essex County, Va., X 75, St. Marys (?) Formation. 

12-15. Cytheretta burnsi (Ulrich and Bassler) (p. 23).

12. Right side of shell; locality D-2, Nansemond County, Va., X 37.5, Yorktown Formation, middle part.

13. Interior of right valve; Mount Gould Landing locality, Bertie County, -N.C., X 37.5, beds 

of Pliocene (?) age.

14. Interior of left valve; Mount Gould Landing locality, Bertie County, N.C., X 37.5, beds of Pliocene (?) age.

15. Right side of female? shell; locality C-l, Nansemond County, Va., X 37.5, Yorktown Formation,

middle part. 

16-18. Cytheretta cf. C. burnsi (Ulrich and Bassler) (p. 23).

Shells in which surface ornamentation is confined to posterior half of valve, either because of abrasion or as an original feature; if the latter, these forms may represent a distinct species or subspecies. Left side of two males? and one female? shell respectively; locality C-l, Nansemond County, 

Va., X 37.5, Yorktown Formation, middle part. 

19,20. Cytheretta porcella (Ulrich and Bassler) (p. 24).

19. Left side of shell; Mount Gould Landing locality, Bertie County, N.C., X 37.5, beds of Pliocene (?) age.

20. Interior of right valve; Mount Gould Landing locality, Bertie County, N.C., X 37.5, beds 

of Pliocene (?) age.

21. Protocytheretta sahnii (Puri) (p. 24).

Right side of shell; locality H-4, Bertie County, N.C., X 37.5, Yorktown Formation, upper part.

22. Cytherura forulata (Edwards) (p. 18).

Left side of shell; locality G-3, Bertie County, N.C., X 71, beds of Pliocene (?) age.

23. Jonesiat sp. (p. 25).

Right side of shell, locality C-l, Nansemond County, Va., X 150, Yorktown Formation, middle part. 

24,25. Xestoleberis cf. X. aurantia (Baird) (p. 25).

Exterior views of left valve and right valve, respectively; Mount Gould Landing locality, X 75, beds

of Pliocene (?) age. 

26,27. Cytheromorpha warneri (Howe and Spurgeon) (p 26).

Exterior of right valve and interior of left valve, locality K-3, Dinwiddie County, Va., X 75, Yorktown Formation, middle part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 2

PONTOCYTHERE, PTERYGOCYTHEREIS, CYTHERETTA, PROTOCYTHERETTA, 

CYTHERURA, JONESIA1,XESTOLEBERIS, AND CYTHEROMORPHA
PLATE 3

[Scanning electron microscope and optical microscope photographs]

FIGURES 1-3. Cytherura elongata (Edwards) (p. 19).

1. Right side of poorly preserved shell; Texas Gulf Sulfur phosphate pit, Beaufort County, N.C., X 

75, Yorktown Formation, 30 feet above base.

2. Left side of a weakly ornamented shell, locality G-3, Bertie County, N.C., X 45, beds of Pliocene (?) age.

3. Interior of right valve; locality A-l, Hertford County, N.C., X 144, Yorktown Formation, lower

part. 

4a, b. Cytherura cf. C. gibba (Miiller) (p. 18).

Left side, X 45, and dorsal, X 45, views of shell; locality G-3, Bertie County, N.C.; beds of Pliocene (?)

age. 

5,6. Cytherura forulata (Edwards) (p. 18).

5. Right side of a shell; locality G-3, Bertie County, N.C., X 45, beds of Pliocene (?) age.

6. Left side of shell; Mount Gould Landing locality, Bertie County, N.C., X 143, beds of Pliocene (?)

age. 

7,8. Cytheropteron &iibreticulatum (van den Bold) (p. 19).

7. Right side of shell; locality A-l, Hertford County, N.C., X 71, lower part of Yorktown Formation.

8. Ventral view of shell; locality R-3, Isle of Wight County, Va., X 91, Yorktown Formation, middle part. 

9-15. Shattuckocythere yorktownensis (Malkin) (p. 22).

9. Exterior of male left valve; Mount Gould Landing locality, Bertie County, N.C., X 150, beds of 

Pliocene (?) age.

10. Dorsal view of female shell; locality A-l, Hertford County, N.C., X 150, lower part of Yorktown 

Formation.

11. Left side of female shell; locality A-l, Hertford County, N.C., X 150, lower part of Yorktown 

Formation.

12. Left side of male shell; locality P-l, Isle of Wight County, Va., X 150, middle part of Yorktown Formation.

13. Interior of left valve; locality P-l, Isle of Wight County, Va., X 150, middle part of Yorktown 

Formation.

14. Right side of female shell; locality A-l, Hertford County, N.C., X 150, lower part of Yorktown 

Formation.

15. Dorsal view of female shell; locality P-l, Isle of Wight County, Va., X 150, middle part of

Yorktown Formation. 

16-21. Hemicytherura howei (Puri) (p. 20).

16. Left side of male shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

17. Interior of right valve; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

18. Right side of female shell; locality S-l, James County, Va., X 75, middle part of Yorktown Formation.

19. Dorsal view of shell; locality S-l, James County, Va., X 75, middle part of Yorktown Formation.

20. Right side of female shell; locality A-5, Hertford County, N.C., X 150, lower part of Yorktown 

Formation.

21. Left side of male shell; locality A-5, Hertford County, N.C., X 150, lower part of Yorktown Formation.

22. Cytheromorpha warneri (Howe and Spurgeon) (p. 26).

Right side of male shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

23. Neocytherideis sp. (p. 17).

Left side of shell; locality S-l, James County, Va., X 45, Yorktown Formation, middle part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 3

CYTHERURA, CYTHEROPTERON, SHATTUCKOCYTHERE, HEMICYTHERURA, 

CYTHEROMORPHA, AND NEOCYTHERIDEIS
PLATE 4

[Scanning electron microscope and optical microscope photographs]

FIGURES 1-4. Cytheromorpha warneri (Howe and Spurgeon) (p. 26).

1. Interior of immature left valve; locality K-3, Dinwiddie County, Va., X 75, Yorktown Formation, 

middle part.

2. Exterior of immature left valve; locality K-4, Dinwiddie County, Va., X 75, Yorktown Formation, 

middle part.

3. Exterior of female right valve; locality K-3, Dinwiddie County, Va., X 75, Yorktown Formation, 

middle part.

4. Interior of immature right valve; locality K-3, Dinwiddie County, Va., X 75, Yorktown Formation,

middle part. 

5-8. Leptocythere paracastanea Swain (p. 26).

5. Interior of female right valve; questionably representing this species, locality G-3, Bertie County, 

N.C., X 75, beds of Pliocene (?) age.

6. Right side of a female? shell compressed and distorted by compaction; locality G-3, Bertie County, 

N.C., X 75, beds of Pliocene (?) age.

7. Right side of a male shell; locality R-3, Isle of Wight County, Va., X 75, Yorktown Formation, 

middle part.

8. Left side of male shell; locality R-3, Isle of Wight County, Va., X 75, Yorktown Formation,

middle part. 

9. Loxoconcha sp. (p. 27).

Left side of shell; locality H-4. Bertie County, N.C., X 75, Yorktown Formation, upper part. 

10. Loxoconcha purisubrhomboidea (Edwards) (p. 27).

Right side of shell; locality D-2, Nansemond County Va., X 75, Yorktown Formation, middle part. 

11,12. Loxoconcha reticularis (Edwards) (p. 28).

Left side and ventral views (the latter slightly oblique) of two shells; locality R-l, Isle of Wight

County, Va., X 75, Yorktown Formation, middle part. 

13. Loxoconcha wilberti (Puri) (p. 28).

Left side of shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age. 

14, 15. Paradoxostoma robustum (Puri) (p. 28).

14. Right side of small immature? shell; locality A-5, Hertford County, N.C., X 75, Yorktown Formation, lower part.

15. Left side of shell; locality S-4, James County, Va., X 75, Yorktown Formation, middle part. 

16-21. Murrayina macleani n. sp. (p. 29).

16. Exterior of holotype male right valve; locality P-2, Isle of Wight County, Va., X 75, Yorktown 

Formation, middle part.

17. Exterior of paratype female right valve; locality P-2, Isle of Wight County, Va., X 75, Yorktown Formation, middle part.

18. Exterior of paratype female left valve; locality P-2, Isle of Wight County, Va., X 75, Yorktown Formation, middle part.

19. Interior of paratype female left valve; locality P-2, Isle of Wight County, Va., X 75, Yorktown 

Formation, middle part.

20. Interior of paratype male? right valve; locality C-l, Nansemond County, Va., X 75, Yorktown 

Formation, middle part.

21. Exterior of a paratype male right valve; locality C-l, Nansemond County, Va., X 75, Yorktown

Formation, middle part. 

22. Actinocythereis exanthemata gomillionensis (Howe and Ellis) (p. 31).

Exterior of right valve; locality R-2, Isle of Wight County, Va., X 75, Yorktown Formation, middle

part. 

23,24. Actinocythereis exanthemata exanthemata (Ulrich and Bassler) (p. 30).

23. Exterior of right valve; locality P-l, Isle of Wight County, Va., X 37.5, Yorktown Formation, 

middle part.

24. Exterior of left valve; locality P-l, Isle of Wight County, Va., X 37.5, Yorktown Formation, middle part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 4

CYTHEROMORPHA, LEPTOCYTHERE, LOXOCONCHA, PARADOXOSTOMA, 

MURRAYINA, AND ACTINOCYTHEREIS
PLATE 5

[Scanning electron microscope and optical microscope photographs]

FIGURES 1,2. Actinocythereis exanthemata exanthemata (Ulrich and Bassler) (p.SO).

1. Dorsal view of shell; locality P-l, Isle of Wight County, Va., X 75, Yorktown Formation, middle part.

2. Right side of shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene(?) age. 

3,4. Cletocythereis mundorffi (Swain) (p. 31).

3. Exterior of left valve; locality A-l, Hertford County, N.C., X 75, Yorktown Formation, 

lower part.

4. Interior of right valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle part. 

5,6. Cletocythereis mundorffi (Swain), subsp. (p. 32).

5. Exterior of right valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle part.

6. Dorsal view of left valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation

middle part. 

7,8. Cletocythereis mundorffi (Swain) subsp. (p. 32).

Exterior views of left valve and right valve respectively; locality C-l, Nansemond County, Va., X

45, Yorktown Formation, middle part. 

9-12. Costa barclayi (McLean) (p. 32).

9. Exterior of female left valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle part.

10. Ventral slightly oblique view of shell; locality K-3, Dinwiddie County, Va., X 75, Yorktown 

Formation, middle part.

11. Exterior of male right valve; locality D-l, Nansemond County, Va., X 75, Yorktown Formation, middle part.

12. Interior of male left valve; locality D-l, Nansemond County, Va., X 75, Yorktown Formation,

middle part. 

13-15. Echinocythereisl clarkana (Ulrich and Bassler) (p. 32).

13. Exterior of immature left valve; locality C-2, Nansemond County, Va., X 75, Yorktown Formation, middle part.

14. Interior of immature right valve; locality C-2, Nansemond County, Va., X 75, Yorktown Formation, middle part.

15. Exterior of left valve, having a somewhat abraded surface; locality C-2, Nansemond County,

Va., X 75, Yorktown Formation, middle part. 

16,17. Bensonocythere whitei (Swain) (p. 33).

16. Exterior of right valve; Mount Gould Landing locality, Bertie County, N.C., X 45, beds of 

Pliocene (?) age.

17. Dorsal view of shell; Mount Gould Landing locality, Bertie County, N.C., X 75, beds of Pliocene (?) age. 

18-20. Campylocythere laeva laeva (Edwards) (p. 34).

18. Exterior of immature left valve; locality C-l, Nansemond County, Va., X 76.5, Yorktown Formation, middle part.

19. Right side of shell; locality G-3, Bertie County, N.C., X 76.5, beds of Pliocene (?) age.

20. Right side of shell with dorsum tilted slightly toward observer; locality C-l, Nansemond

County, Va., X 76.5, Yorktown Formation, middle part. 

21-24. Campylocy there laeva posteropunctata (Edwards) (p. 34).

21. Exterior of right valve; locality C-l, Nansemond County, Va., X 76, Yorktown Formation, middle part.

22. Interior of left valve; locality C-l, Nansemond County, Va., X 76, Yorktown Formation,

middle part.

23, 24. Dorsal and ventral views respectively of two shells; locality G-3, Bertie County, N.C., X 76.5, 

beds of Pliocene (?) age.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 5

ACTINOCYTHEREIS, CLETOCYTHEREIS, COSTA, ECHINOCYTHEREISl, 

BENSONOCYTHERE, AND CAMPY LOCYTHERE
PLATE 6

[Scanning electron microscope and optical microscope photographs]

FIGURE 1. Campylocythere laeva laeva (Edwards) (p. 34).

Interior of left valve; locality G-3, Bertie County, N.C., X 76.5, beds of Pliocene (?) age. 

2,3. Acuticythereis laevissima punctata (Edwards) (p. 34).

2. Right side of shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

3. Interior of left valve; locality S-3, James County, Va., X 75, Yorktown Formation, middle

part. 

4-6. Acuticythereis laevissima laevissima (Edwards) (p. 35).

4. Exterior of left valve; locality G-3, Bertie County, N.C., X 76.5, beds of Pliocene (?) age. 

5, 6. Interior views of left and right valves, respectively of a specimen; Lumberton, N.C., X 76.5,

Duplin Formation. 

7. Acuticythereis'! sp. (p. 35).

Exterior of a right valve; locality A-5, Hertford County, N.C., X 75, Yorktown Formation, lower

part. 

8-10. Prodictyocythere trapezoidalis, n. gen. n. sp. (p. 35).

8. Exterior of holotype left valve; locality C-l, Nansemond County, Va., X 76.5, Yorktown Formation, middle part.

9. Exterior of paratype right valve; locality C-l, Nansemond County, Va., X 76.5, Yorktown Formation, middle part. 

lOa, b. Exterior of left valve, X 100, and enlargement of dorsal surface, X 375, showing normal pores;

locality A-l, Hertford County, N.C., Yorktown Formation, lower part. 

11-13. Radimella confragosa (Edwards) (p. 36).

Right sides and ventral view of three shells; Mount Gould Landing locality, Bertie County, N.C., X 75,

beds of Pliocene (?) age. 

14-18. Aurila conradi (Howe and McGuirt) (p. 37).

All are from locality K-4, Dinwiddie County, Va., Yorktown Formation, middle part.

14,15, 17. Right sides of three shells in which greatest height is well anterior to midlength, X 75. 

16. Dorsal view of shell, X 75. 

18. Right side of shell in which greatest height is near midlength, X 75.

19. Thaerocythere schmidtae (Malkin) (p. 40).

Interior of right valve; locality A-l, Hertford County, N.C., X 75, Yorktown Formation, lower part.

20. Caudites sp. (p. 37).

Right side of shell; locality G-3, Bertie County, N.C., X 150, beds of Pliocene (?) age.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 6

CAMPYLOCYTHERE, ACUTICYTHEREIS, PRODICTYOCYTHERE, 

RADIMELLA, AURILA, THAEROCYTHERE, AND CAUDITES
PLATE 7

[Scanning electron microscope and optical microscope photographs]

FIGURES 1-8. Muellerina micula (Ulrich and Bassler) (p. 38).

1. Left side of immature shell; locality C-l, Nansemond County, Va., X 76.5, Yorktown Formation, middle part.

2. Right side of shell, locality C-l, Nansemond County, Va., X 76.5, Yorktown Formation, middle 

part.

3. Interior of left valve; locality A-l, Hertford County, N.C., X 76.5, Yorktown Formation, lower 

part.

4. Interior of right valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle 

part.

5. Interior of left valve; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle 

part.

6. Left side of shell; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle 

part.

7. Right side of shell; locality C-l, Nansemond County, Va., X 76, Yorktown Formation, middle part.

8. Dorsal view of shell; locality C-l, Nansemond County, Va., X 75, Yorktown Formation, middle

part. 

9-15. Thaerocythere schmidtae (Malkin) (p. 40).

Positions of normal pores are shown on most of the specimens; sieve plates were not observed.

9. Left side of female shell; locality S-5, James County, Va., X 75, Yorktown Formation, middle 

part.

10. Dorsal view of female shell; locality A-l, Hertford County, N.C., X 75, beds of Pliocene (?) age.

11. Right side of male shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

12. Exterior of female right valve; locality A-l, Hertford County, N.C., X 75, Yorktown Formation, 

lower part.

13. Left side of female shell; locality A-l, Hertford County, N.C., X 76.5, Yorktown Formation, lower 

part.

14. Left side of female shell; locality A-l, Hertford County, N.C., X 75, Yorktown Formation, lower 

part.

15. Interior of female left valve; locality A-l, Hertford County, N.C., X 76.5, Yorktown Formation, 

lower part.

16. Thaerocythere sp. (p. 40).

Left side of shell; locality G-3, Bertie County, N.C., X 75, beds of Pliocene (?) age.

17. Orionina vaughani (Ulrich and Bassler) (p. 39).

Exterior of left valve; K-4, Dinwiddie County, Va., X 76.5, Yorktown Formation, middle part.

18. Puriana mesacostalis (Edwards) (p. 42).

Exterior of immature right valve; locality K-4, Dinwiddie County, Va., X 75, Yorktown Formation,

middle part. 

19-20. Puriana rugipunctata (Ulrich and Bassler) (p. 41).

19. Exterior of left valve; locality K-4, Dinwiddie County, Va., X 75, Yorktown Formation, middle 

part.

20. Exterior of right valve; locality K-4, Dinwiddie County, Va., Yorktown Formation, middle part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 7

MUELLERINA, THAEROCYTHERE, ORIONINA, AND PURIANA
PLATE 8

[Transmitted light photographs]

FIGURES 1. Acuticythereis laevissima laevissima Edwards (p. 35).

Interior of right valve of a complete shell, Lumberton, N.C., locality, X 95, Duplin Marl. 

2a, b. Cytheromorpha warneri Howe and Spurgeon (p. 26).

Interior views of right valve at two levels of focus, locality E, Hertford County, N.C., X 77, Yorktown

Formation, upper part. 

3. Campylocythere laeva posteropunctata Edwards (p. 34).

Interior of left valve, locality G-3, Bertie County, N.C., beds of Pliocene (?) age, X 77. 

4a, b. Cushmanidea fabula (Howe and Dohm) (p. 15).

Interior of left valve, X 77, and muscle scar, X 220, locality N-l, Surry County, Va., Yorktown Formation, lower part. 

5,12. Acuticythereis laevissima laevissima Edwards (p. 35).

Muscle scar, X 220, and detail of anterior margin, X 220, of left valve of same shell shown on Plate

8, figure 1. 

6. Prodictyocythere trapezoidalis, n. gen., n. sp. (p. 35).

Interior of paratype right valve, locality C-l, Nansemond County, Va., X 150, Yorktown Formation,

middle part. 

7a, b. Cytherura elongata Edwards (p. 19).

Interior of left valve, X 77, and detail of anterior margin X 220, locality K-3, Dinwiddie County, Va.,

Yorktown Formation, middle part. 

8a c. Murrayina macleani, n. sp. (p. 29).

Interior views of right valve at different levels of focus, X 75, and detail of anterior margin X 220,

locality P-2, Isle of Wight County, Va., Yorktown Formation, middle part. 

9. Shattuckocythere shattucki (Ulrich and Bassler) (p. 21).

Interior of left valve, locality P-l, Isle of Wight County, Va., X 105, Yorktown Formation, middle

part. 

lOa, b. Haplocytheridea bradyi (Stephenson) (p. 13).

Interior of right valve, X 77, and detail of anterior margin, X 220, Mount Gould Landing locality,

Bertie County, N.C., beds of Pliocene (?) age. 

lla c. Cytheretta burnsi (Ulrich and Bassler) (p. 23).

Interior of right valve, X 52, and details of anterior and posterior margins, X 220, Mount Gould 

Landing locality, Bertie County, N.C., beds of Pliocene (?) age.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821, PLATE 8

ACUTICYTHEREIS, CYTHEROMORPHA, CAMPYLOCYTHERE, CUSHMANIDEA, PRODICTYOCYTHERE, CYTHERURA, 

MURRAYINA, SHATTUCKOCYTHERE, HAPLOCYTHERIDEA, AND CYTHERETTA
PLATE 9

[Transmitted light photographs]

FIGURES la-d. Thaerocythere schmidtae (Malkin) (p. 40).

Inerior of left valve at two levels of focus, X 77, and details of posterior and anterior margins, X 

220, locality E, Hertford County, N.C., Yorktown Formation, upper part.

2. Cytherura elongata Edwards (p. 19).

Interior of right valve, locality A-l, Hertford County, N.C., X 105, Yorktown Formation, lower part.

3. Cytheropteron subreticulatum van den Bold (p. 19).

Transmitted light view of left valve from outside, locality FP-1, 0.5 of a mile south of Flag Pond, Calve rt County, Md., X 105, Choptank Formation. 

4a, b. Hemicytherura howei (Puri) (p. 20).

Interior of right valve, X 105, and detail of anterior margin, X 220, locality G-3, Bertie County,

N.C., beds of Pliocene (?) age. 

5. Pterygocythereis americana (Ulrich and Bassler) (p. 23).

Interior of immature right valve, locality U-l, Essex County, Va., X 105, Yorktown (?) Formation,

lower part, or St. Marys (?) Formation. 

6a, b. Leptocythere paracastanea Swain (p. 26).

Interior views of left valve at different levels of focus, locality R-3, Isle of Wight County, Va., X 

105, Yorktown Formation, middle part.

7. Loxoconcha sp. (p. 27).

Interior of left valve, X 77, locality H-4, Bertie County, N.C., Yorktown Formation, upper part.

8. Cytheromorpha warneri Howe and Spurgeon (p. 26).

Interior of right valve, locality K-3, Dinwiddie County, Va., X 105, Yorktown Formation, middle part. 

9a, b. Shattuckocythere yorktownensis (Malkin) (p. 22).

Interior views of left valve at two levels of focus, locality P-l, Isle of Wight County, Va., X 105,

Yorktown Formation, middle part. 

lOa, b. Costa barclayi (McLean) (p. 32).

Interior of left valve, X 77, and detail of anterior margin, X 220, locality K-4, Dinwiddie County, Va.,

Yorktown Formation, middle part. 

11. Costa barclayi (McLean) (p. 32).

Interior of left valve, locality O-l, near Cobham Wharf, Surry County, Va., X 77, Yorktown Formation undivided. 

12a, b. Pontocythere (Hulingsina) ashermani (Ulrich and Bassler) (p. 16).

Interior of left valve, X 77, and detail of anterior margin, X 220, locality G-3, Bertie County, N.C., 

beds of Pliocene (?) age.

13. Murrayina macleani, n. sp. (p. 29).

Interior of female paratype right valve, locality C-l, Nansemond County, Va., X 77, Yorktown Formation, middle part.

14. Shattuckocythere similis (Malkin) (p. 22).

Interior of immature left valve, locality at Mount- Gould landing, Bertie County, N.C., X 105, beds 

of-Pliocene (?) age.

15. Loxoconcha wilberti Puri (p. 28).

Interior of right valve, locality S-5, James, County, Va., X 105, Yorktown Formation, middle part.

16. Haplocytheridea setipunctata (Brady) (p. 12).

Interior of right valve, X 52, Seaboard Air Line Railroad Bridge locality, Northampton County, 

N.C., Yorktown Formation, lower part.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 9

THAEROCYTHERE, CYTHERURA, CYTHEROPTERON, HEMICYTHERURA, PTERYGOCYTHEREIS. CYTHEROMORPHA

- ^,r^^^* r ^ rr . ^.^^^ . .^.rm^^TT^rrr^-i- » ^ r rr. n » VT iv r A o rj >i T"rT J/^V r\r^ VTUITD K~ AWF» HA PJ DC YTHF.R IDEA
PLATE 10

[Scanning electron microscope photographs]

FIGURES la-g. Actinocythereis exanthemata exanthemata (Ulrich and Bassler) (p. 30).

a, interior of right valve with dorsum tilted toward viewer, X 106; b, c, dorsal views of right valve at 

slight angle of tilt and greater angle of tilt from vertical, respectively, X 50; d, detail of anterior 

hinge tooth and socket, X 270; e, detail of posterior hinge tooth, X 270; /, detail of middle part 

of hinge margin, X 270; g, detail of adductor muscle scar area, dorsal part tilted toward viewer, 

X 247, Yorktown Formation, middle part, locality C-2, Nansemond County, Va.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 10

A CTINOC YTHER EIS
PLATE 11

[Scanning electron microscope photographs]

FIGURES la-d. Cletocythereis mundorffi (Swain) (p. 31).

a, exterior of left valve, X 188; 6, dorsal view of left valve, X 93; c, detail of anterodorsal cardinal 

projection, X 376; d, detail of medial surface ornamentation, X 517, Yorktown Formation, middle 

part, locality C 1, Nansemond County, Va. 

2a-e. Bensonocythere whitei (Swain) (p. 33).

a, interior of right valve, X 70; 6, enlargement of posterior part of right valve, X 178; c, normal canal 

opening to interior and containing a secondary calcite crystal, X 3000; d, enlargementment of posteroventral margin of interior of right valve, X 241; e, enlargement of anteroventral margin of interior of right valve, X 241, Yorktown Formation, middle part, locality C-l, Nansemond County, 

Va.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 11

CLETOCYTHEREIS AND BENSONOCYTHERE
PLATE 12

[Scanning electron microscope photographs 1

FIGURES la-f. Bensonocy'there tvhitei (Swain) (p. 33).

a, interior of right valve, X 50; 6, c, exteriors of two right valves, X 50; d, adductor muscle scar of 

right valve showing furrow-to-ridge marginal configuration, shell surface tilted away from observer, X 600; e, oblique view of a normal canal opening on interior of valve, X 6,000; /, normal 

canal with marginally perforated sieve plate opening on valve exterior, X 3,000, Yorktown. Formation, middle part, locality C-l, Nansemond County, Va. 

2a-h. Orionina vaughani (Ulrich and Bassler) (p. 39).

a, exterior of right valve X 50; 6, interior of right valve, X 50; c, enlargement of a normal canal, 

opening to the interior, X 6,000; d, enlargement of normal canal opening to exterior of valve, 

sieve plate apparently recrystallized but weakly perforate, X 3,000; e, anteromedian part of 

valve interior showing adductor and frontal muscle scar spots, note narrow rims on spots, X 400; 

/, enlargement of adductor muscle scar, X 600; g, enlargement of posteromedian surface ornamentation, X 600; h, enlargement of median surface ornamentation, X 400, Yorktown Formation, middle part, locality C-l, Nansemond County, Va.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 12

BENSONOCYTHERE AND ORIONINA
PLATE 13

[Scanning electron microscope photographs]

FIGURES la-g. Aurila conradi (Howe and McGuirt) (p. 37).

a, interior of left valve with hinge margin tilted toward observer, X 120; 6, enlargement of normal canal, 

X 6,000; c, ventral view of left valve, X 65; d, dorsal view of left valve, X 65; e, enlargement 

of muscle scar area, X 600; /, enlargement of hinge margin of left valve, X 450; g, enlargement 

of anterodorsal part of right valve, X 600, Yorktown Formation, middle part, locality C-l, Nansemond County, Va. 

2a-c. Peterygocythereis americana (Ulrich and Bassler) (p. 23).

a, 6, left sides of two shells, X 48; c, enlargement of surface of a, X 190 showing scattered normal 

pores, lower 1.5 feet of Yorktown Formation, Lees Creek Pit, Texas Gulf Sulphur Co., Beaufort 

Co., N.C. a and 6 are slightly tilted to right of observer.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 821 PLATE 13

AURILA AND PTERYGOCYTHEREIS