Ostracoda from Wells 

in North Carolina

Part 1, Cenozoic Ostracoda

GEOLOGICAL SURVEY PROFESSIONAL PAPER 234-A
Ostracoda from Wells 

in North Carolina

Part 1, Cenozoic Ostracoda

By FREDERICK M. SWAIN

GEOLOGICAL SURVEY PROFESSIONAL PAPER 234-A

Descriptions, illustrations, 

geographic distribution, and 

stratigraphic ranges of 

microfossils.

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1951
UNITED STATES DEPARTMENT OF THE INTERIOR

Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY

W. E. Wrather, Director

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

Washington 25, D. C. - Price 75 cents (paper cover)
CONTENTS

Abstract- ------__-_-_____-__________-______________

Introduction _______________________________________

List of wells_______________________________________

Stratigraphic summary______________________________

Paleocene (?) series.____________________________

Eocene series__________________________________

Lower Eocene._____________________________

Middle Eocene (and upper Eocene (?) )_______

Oligocene or lower part of Miocene series,_________

Miocene series.__________________J______________

Pliocene series._________________________________

Pleistocene series_______________________________

Recent series.__________________________________

Mollusks from the Esso Standard Oil Co. Hatteras Light 

well no. l______-_-___-_________-_________________

Stratigraphy of water wells in eastern North Carolina. __

Cenozoic rocks in Esso Standard Oil Co. Hatteras Light

well no. 1._______________________________________

Tertiary rocks in Esso Standard Oil Co. North Carolina 

Esso well no. 2__.________________________________

Systematic descriptions..____________________________

Cytherellidae ___-________-___--_____--___---___

Cytherella,- ___ _ ____________________________

Cytherelloidea___ _ ___________________________

Cypridae ____________--______-_-_-___-____--___

Paracypris, ________________________________

Bairdiidae. ________-_-___-_-----_-___-___-_____

Bairdia_ _________________________________

Triebelina,-- ___-_-_-_______-_____-_-___---_

Bairdoppilatct-.-. ___________________________

Bythocypris, _______________________________

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Systematic descriptions—Continued 

Cytheridae_ _ _ ________________

Xestoleberis _ ______________

Eucythere __________________

Cytheridea. _______________

Cytherideis. _ _______--__-__

Haplocytheridea_ __________

Clithrocytheridea ___________

Loxoconcha_ -___________--

Trachyleberis ______________

Buntonia ________-__---_-_

Favella. __________________

Pterygocythereis-. ___________

Caudites __________________

Acuticythereis _ _ __________

Hemicythere- ______________

Leguminocythereis- _________

Brachycythere- _____________

Cytheretta. ________________

Basslerites. _ ______________

Eocytheropteron. ___________

Cytheropteron- _____________

Cytheromorpha_ __________

Cytherura- ________________

MonoceratincL- _____________

Paracytheridea- ____________

Pellucistoma- ______________

References ________________________

Index _____________----_-----__-_-

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ILLUSTRATIONS

• Page

PLATES 1-7. Cytherellidae, Cypridae, Bairdiidae, Cytheridae________--_-------------------------~---------- Following index

FIGUEE 1. Index map showing eastern North Carolina localities studied_____________________-___--_--___----------- 2

2. Stratigraphic relationships of Cenozoic rocks in Esso Standard Oil Co. Hatteras Light well no. 1 and North

Carolina Esso well no. 2, eastern Dare County, N. C________-__------_-_--_---------------__-----_-_- 5

3. Cytherellidae and Cytheridae_______-____-___-__________-----------------------____------------------ 15

in

OSTRACODA FROM WELLS IN NORTH CAROLINA

PART 1, CENOZOIC OSTRACODA

By FREDERICK M. SWAIN

ABSTRACT

Cenozoic Ostracoda obtained from wells and surface exposures in North Carolina are described. Eight of the species 

are new. This work provides our first knowledge of the preMiocene Cenozoic Ostracoda in North Carolina. The names of 

the surface 'Cenozoic formations are not applied to the subsurface units in this paper because of uncertainties in correlation; instead, the more general terms Paleocene (?), lower 

Eocene, middle Eocene, Oligocene or lower Miocene, lower Miocene, middle Miocene, upper Miocene, Pliocene, Pleistocene, and 

Recent are used.

The Paleocene (?) rocks consist of fine-grained, sandy, glauconitic shale and marl, and contain tiny benthonic Foraminifera. 

The unit is 277 feet thick beneath Cape Hatteras and thins 

abruptly westward. Its tentative assignment to Paleocene is 

based on stratigraphic position and on the fact that it differs 

markedly in lithologic character and fauna from the adjoining 

units.

The lower Eocene consists of as much as 485 feet of finegrained glauconitic sandstone and sandy limestone in which, 

from Cape Hatteras southwestward, many layers are highly 

siliceous. Brachycythere marylandica (Ulrich), Bythocypris 

parilis Ulrich, Cytherelloidea howei Swain, Haplocytheridea 

hopkinsi, (Howe and Garrett), Trachyle'beris? sp. aff. T.f cornmunis aquia, (Schmidt), and Xestoleberis cf. X. longissima 

Schmidt are ostracodes characteristic of the lower Eocene.

The middle Eocene rocks are coarse-grained, glauconitic, sandy 

limestones and calcareous sandstones with a maximum total 

thickness of 647 feet. This zone contains abundant ostracodes 

of which many are indicative of Claiborne age. The species that 

are restricted to the unit are: Buntonia howei (Stephenson), 

Clithrocytheridea cf. C. smithvillensis Stephenson, Cytheretta 

daren§is Swain, n. sp., Cytheromorpha cf. C. eocenica Stephenson, Cytheropteron cf. C. variosum Martin, Cythet-ura sp. aff. C. 

loashburni Stephenson, Haplocytheridea cf. H. goochi Stephenson, H. cf. H. noicotnyi Stephenson, Loxoconcha sp. aff. L. claibornensis Murray, L. cf. L. mcbeanensis Murray, L. cf. L. surreala Murray, Monoceratina, cf. M. harrisi Stephenson, Pterygocythereis washingtonensis Swain, n. sp., T.f rukasi (Gooch), 

and T. smithvillensis (Sutton and Williams).

The upper Eocene rocks, if present in the subsurface of eastern 

North Carolina, do not contain a distinctive ostracode fauna.

A unit of sandstone, glauconitic shale, and sandy limestone 

beds totalling as much as 258 feet thick overlying the middle 

Eocene in the two deep Esso Standard Oil Co. wells, Dare 

County, is here referred to the Oligocene or lower Miocene.

The lower Miocene apparently occurs in two facies in eastern 

North Carolina. At Cape Hatteras and southwestward the 

lower Miocene is represented by as much as 485 feet of sandy, 

mostly nonglauconitic limestone and sand, probably representing 

the Trent marl of surface exposures. North of Cape Hatteras 

there is a facies change to gray diatomaceous shale.

The middle Miocene beds may represent the St. Marys formation of surface exposures; it consists of fossiliferous shaly 

sands and sandy clay as much as 340 feet thick. Paracytherideal weatherelli (Jones) and Trachylebris rosetta Swain, n. sp. 

were found only in the unit. The highest occurrence of Trachyleberis evax (Ulrich and Bassler) was used in selecting the 

upper boundary of the middle Miocene.

The upper Miocene consists of a maximum of 560 feet of 

unconsolidated sand and shell beds that probably represent trfe 

Yorktown formation and the Duplin marl of surface exposures. 

The following ostracodes are restricted to the upper Miocene: 

Acuticythereis laevissima, punctata Edwards, A. cf. A. multipunctata Edwards, Basslerites cf. B. giffanticus Edwards, Cytheromorpha curta Edwards, Cytherura cf. C. reticulata Edwards, Favella mesicostalis Edwards,, Hemicythere confragosa 

Edwards, Loxoconcha edentonensis Swain, n. sp. Paracytheridea, 

cf. P. rugosa Edwards, Pellucistoma cf. P. magniventra Edwards, 

Trachyleberis'! triplistriata, Edwards, Xestoleberisl ventrostriata Swain, n. sp.

The Pliocene, Pleistocene, and Recent are not clearly distinguishable lithologically in the wells.

The Tertiary ostracode fauna of the North Carolina wells is 

strikingly similar to those of the Gulf region but several problems of correlation and facies relationships remain unsolved.

INTRODUCTION

Several collections of Mesozoic and Cenozoic Ostracoda from water wells and exploratory oil wells in the 

coastal plain of eastern North Carolina (Fig. 1) have 

been furnished to the Geological Survey. The species 

of Cenozoic ostracodes obtained from 13 wells are recorded in this paper, and a second paper will discuss the 

Cretaceous species. The only published study on the 

North Carolina Cenozoic ostracodes is that by Edwards 

(1944), who provided excellent descriptions of the 

upper Miocene Duplin marl species. McLean (1947) 

listed several species from the Miocene and Oligocene 

occurring in a water well at Camp Lejeune, Onslow 

County, N. C.
OSTRACODA FROM WELLS IN NORTH CAROLINA

77°

I GATES \-r '-\^

~N__ -**\ *^ ^

/ C.-X /HERTFORD V-M \ * 

H A L I F A X \ / ____I ..—— .-Jo /

A R T I M'X /WASHINGTON /TYRRE

\____.__/

H N S T 0 N /

CsAMPSONlQ 

'^s ! X

0 N*S L 0 W

78° 77' ^T

FIGURE 1.—Index map of eastern North Carolina showing localities studied.

The Cenozoic Foraminifera of surface exposures in lished report deals with several of the water wells

North Carolina are better known (Cushman, 1918,1935; involved in the present study. A large collection of

Cushman and Cahill, 1933). McLean (1947) and Cush- Foraminifera was obtained from the Hatteras Light

man (unpublished report dated April 24, 1946) re- well no. 1, located on Cape Hatteras, but study of the

corded Miocene, Oligocene, and Eocene species of Fora- material has not been completed by the Geological

minifera from some water wells. Cushman's unpub- Survey.
CENOZOIC OSTRACODA

Because it seems inadvisable to apply the names of 

the surface Cenozoic formations to units occurring in 

the wells, only a generalized stratigraphic classification 

is used, as follows:

Quaternary system 

Recent series 

Pleistocene series 

Tertiary system 

Pliocene series 

Miocene series

Upper Miocene

Middle Miocene

Lower Miocene

Lower part of Miocene series or Oligocene 

Eocene series

Middle Eocene 

Lower Eocene 

Paleocene (?) series

The stratigraphy of these units and their ostracode 

faunas are briefly described. The ranges of some species recorded from the water wells may be inaccurate 

due to the caving of walls during drilling; in picking 

specimens from the exploratory oil well samples an 

attempt was made to eliminate specimens that might 

have been displaced by caving, but some inaccuracies 

may remain.

A recent informative paper by Spangler (1950) gives 

data on the subsurface stratigraphy in eastern North 

Carolina. According to Spangler (1950, pp. 120, 121) 

the Cenozoic rocks in the Esso Standard Oil Co., Hatteras Light well no. 1 can be subdivided as follows: 

Recent and Pleistocene 0-110 feet, Pliocene 110-320 

feet, upper Miocene (Yorktown) 320-750 feet, middle 

Miocene (Calvert) 750-994 feet, lower Miocene (Trent) 

994-1,480 feet, Eocene, 1,480-2440 feet; the top of the 

Cretaceous (Peedee formation) is placed at 2,440 feet.

Spangler's subdivisions of the Cenozoic in the Esso 

Standard Oil Co., North Carolina Esso well no. 2 are: 

Recent, Pleistocene, and Pliocene 0-300 feet, Miocene 

300-1,265 feet, Eocene 1,265-1,750 feet; the top of the 

Cretaceous was placed at 1,750 feet.

Presumably, Spangler's correlations of these two 

wells were based on study of the drill-cuttings, cores, 

electrical logs and Foraminifera. Concerning the top 

of the Cretaceous in the two wells Spangler (1950, pp. 

130,131) states: "No foraminiferal fauna by which the 

true age of the Peedee could be determined was found 

in the North Carolina Esso no. 2 and Hatteras no. 1 

and correlations were made on electric-log characteristics." The present author placed the top of the Cretaceous in both wells at a lower level on the basis of 

the ostracodes, as hereinafter stated.

Acknowledgments. The writer appreciates material and information received from K. D. White and 

W. B. Spangler of the Esso Standard Oil Co., W. S. 

Pike and Doris Malkin of the Shell Oil Co., Inc., and 

M. J. Mundorff, J. B. Reeside, Jr., J. A. Cushman, Julia 

Gardner, and F. Stearns MacNeil of the U. S. Geological Survey. L. E. Monley, L. M. Perry, J. A. Peterson, 

and W. D. Quinlivan of the U. S. Geological Survey, 

assisted in various ways. The bibliographic work and 

some of the laboratory work were done by Richard E. 

Hadley and Robert H. Cress, supported by a grant-inaid from the Graduate School, University of Minnesota.

LIST OF WELLS

In the following list asterisks (*) indicate wells 

from which ostracodes were obtained. Information 

from the other wells helped work out stratigraphic relationships. The kinds of information concerning each 

well is indicated. The well numbers are used in the 

faunal table (pp. 12-14) to identify the wells in which 

the various ostracode species are found.

*1. Esso Standard Oil Co. Hatteras Light.well* no. 1; 

Long. 75°31'4" W., Lat. 35°15'0.5" N., Cape Hatteras, 

Dare County, N. C.; derrick floor altitude 24 feet; depth 

10,054 feet; drill-cuttings, cores, electrical log, drilling 

time log; report by Julia Gardner on macrofossils; 

stratigraphy briefly described by Swain (1947).

*2. Esso Standard Oil Co., North Carolina Esso well 

no. 2; Long. 75°33'54" W., Lat. 35°42'12" N., Pamlico 

Sound, Dare County, N. C.; drive bushing altitude 21 

feet; depth 6,410 feet; drill cuttings, electrical log; 

stratigraphy summarized by Swain (1947).

*3. Naval Auxiliary Air Station well; Washington, 

Beaufort County, N. C., about 2% miles northeast of 

city; altitude about 33 feet; depth 215 feet; ostracodes, 

unpublished report by Cushman on Foraminifera.

*4. Edenton Naval Air Base well no. 1; Chowan 

County, N. C., 3 miles southeast of center of Edenton; 

altitude 15 feet; depth 55 feet; ostracodes, unpublished 

report by Cushman on Foraminifera.

*5. Edenton Naval Air Base well no. 4; one mile 

southeast of preceding; altitude 10 feet; depth 88 feet; 

ostracodes.

1 These two wells were originally termed (Swain, 1947) the Standard 

Oil Company (N. J.) North Carolina Esso no. 1 and North Carolina 

Esso no 2 wells. The exploration section of the company has since 

bpen renamed the Esso Standard Oil Company and the name of the 

no. 1 well has been changed to Hatteras Light well no. 1.
OSTRACODA FROM WELLS IN NORTH CAROLINA

*6. Williamston test well no. 2; Martin County, N". 

C.; about y2 mile east of center of town; altitude about 

60 feet; depth about 220 feet; ostracodes.

*7. Jacksonville Tent Camp well no. 2; Onslow 

County, N. C.; 2 miles S. 45° W. of town; altitude 20.3 

feet; depth 184 feet; ostracodes.

*8. Harvey Neck water well; Perquimans County, 

N. C., on Harvey Point, 1% miles from tip of point, 

1/2 mile southeast of Perquimans River; altitude about 8 

feet; depth 77 feet; ostracodes.

*9. Bogue water well no. 65; Carteret County, N. C., 

at Bogue, about 6 miles east of Swansboro; altitude 

181/2 feet; depth 260 feet; ostracodes.

*10. Layne Housing project water well; Jacksonville, N. C., 5% miles S. 20° E. of Jacksonville; altitude 32.2 feet; depth 125 feet; ostracodes, unpublished 

report by Cushman on Foraminifera.

*11. Cape Lookout water well; Carteret County, 

N. C., about 10.5 miles southeast of Beaufort; altitude 

not known, probably 5 to 10 feet above sea level; depth 

435 feet; ostracodes, unpublished report by Cushman on 

Foraminifera.

*12. Great Lakes Drilling Co. well; 5 miles west of 

Havelock, Craven County, N". C. altitude about 30 feet; 

depth 2,531 feet; drill-cuttings, unpublished report by

Doris L. Malkin of Shell Oil Co.; log of well published 

(Mansfield, 1927, Mundorff, 1944).

*13. F. L. Karsten, Laughton no. 1 well; Morehead 

City, Carteret County, N". C.; altitude 17 feet; depth 

4,044 feet; drill-cuttings, electrical log, summarized log 

published (Richards, 1948, p. 59).

14. Carolina Petroleum Co., O. L. Phillips-State of 

N. C. no. 1 well, 1% miles north of Merrimon, Carteret 

Co., N. C.; altitude 10 feet, estimated; depth 3,964 feet; 

electrical log.

15. Carolina Petroleum Co., Nita Carraway no. 1 

well, 2 miles south of Merrimon, Carteret Co., JN. C.; 

altitude 10 feet, estimated; depth 4,126 feet; electrical 

log.

16. Carolina Petroleum Co., Guy M. Carraway no. 1 

well, at Merrimon, Carteret Co., N". C.; altitude 8 feet; 

depth 4,069 feet; electrical log.

17. Carolina Petroleum Co., H. B. Salter no. 1 well, 

1V4 miles north of Merrimon, Carteret Co., N. C.; altitude 8 feet; depth 3,963 feet; electrical log.

18. Carolina Petroleum Co., Charles Bryan no 1 well; 

1 mile east of Ellis Lake, Craven Co., N. C.; altitude 

15 feet, estimated; depth 2,435 feet; electrical log.

19. Carolina Petroleum Co., N. C. Pulpwood no. 1 

well; 1 mile southwest of Pamlico, Pamlico Co., N. C.; 

altitude 4 feet; total depth 3,666 feet; electrical log.

Correlation of Tertiary strata in North Carolina wells

[Correlations of the Carolina Petroleum Co. wells are based on electrical logs obtained from the Riley Blueprint Co., Jackson, Miss. All figures are depths In feet below

surface]

1. *Esso Standard Oil Company, Hatteras 

Light well no. 1, Dare County. 

2. *Esso Standard Oil Company, North Carolina Esso well no. 2, Dare County. 

3. *Naval Auxiliary Air Station well, Washington, North Carolina.

County. 

5. *Edenton Naval Air Base well no. 4, Chowan

County. 

6. *Williamston test well no. 2, Martin County

County.

9. *Bogue well no. 65, Carteret County.___.__..

ty. 

11. *Cape Lookout well, Carteret County _ .. .

12. *Great Lakes Drilling Co. well, Craven

County. 

13. *F. L. Karsten, Laughton no. 1, Carteret

County. 

14. Caroline Petroleum Company, PhillipsState of North Carolina no. 1, Carteret 

County. 

15. Carolina Petroleum Company, Nita Carraway no. 1, Carteret County.

raway no. 1, Carteret County. 

17. Carolina Petroleum Company, H. B. Salter

no. 1. Carteret County.

no. 1, Craven County.

lina Pulpwood no. 1, Pamlico County.

wood no. 1, Pamlico County.

Top of 

Pleistocene

50±

Top of Pliocene

120±

Top of 

upper Miocene

160±

i on i

60±

P30±

45±

43?

130?

OA I

55

Top of 

middle Miocene

720± 

460?

en i

70dh

Qfi-4-

df\

63±

75±

60?

Top of 

lower 

Miocene

995

QAfl

10

120?

336±

Top of 

lower 

Miocene 

or Oligocene

1,480 

1,265

AVVf

165?

Top of 

middle 

Eocene

1,738

90

105

385±

325

950

740

927

835

787

754

855

830

Top of 

lower 

Eocene

2,385

1 7^5

175

560±

1,080

912

1,065

997

960

850?

956

910

Top of 

Paleocene (?)

2, 870± 

2,036±

685±

1,333

1,152

1,255

1,204

1,175

930

1,150

1,090

Top of 

upper 

Cretaceous

3,033 

2,225

740

1,440

1,278

1,402

1,345

1,300

1,010

1,195

1,118

Depth 

of well

10,054 

6,410

215

55

88

220±

184

77

260

427?

435

2,351

4,044

3,964

4,126

4,069

3,963

2,435

3,666

3,425

Oldest rock penetrated

Precambrian granite.

Middle Miocene.

(?).

(?)-

Upper Miocene (?).

Middle Eocene (?).

Precambrian granite.

„ it

«

n «

<! «

« «

,, «

« «

* Qstracode specimens used in present study obtained from this well. Stratigraphic ranges of species are indicated in table on p. 12.
CENOZOIC OSTRACODA

20. Carolina Petroleum Co., Atlas Plywood no. 1 

well; iy2 miles northwest of preceding; altitude 8 feet; 

depth 3,425 feet; electrical log.

Mr. Mundorff supplied ostracodes from the following surface exposures:

*21. Natural Well, iy2 miles north of Magnolia, 

Duplin County, N. C.; Duplin marl; ostracodes; Edwards (1944) described several species from this locality.

*22. Railroad station pit at Pollacksville, Jones 

County, N. C.; Castle Hayne marl; ostracodes.

STRATIGRAPHIC SUMMARY

The first table (p. 4), lists the wells from which information was obtained, and when known, the Cenozoic 

subdivisions, the top of the Cretaceous, the total depth 

of the well and the oldest rock penetrated. The table 

on pages 12-14 summarizes the ranges of the ostracode 

species and their occurrence in the wells. The geheralized stratigraphic relationships of the Cenozoic rocks in 

the Esso Standard Oil Company's Hatteras Light well 

no. 1, and the North Carolina Esso well no. 2 are shown 

in Figure 2.

PALEOCENE (?) SERIES

The strata here assigned tentatively to the Paleocene 

occur only in the deep wells bordering Pamlico Sound, 

and samples of the material were seen only from two 

wells, the Hatteras Light no. 1 and the North Carolina 

Esso no. 2 (Fig. 2). The Paleocene (?) is 277 feet thick 

in the North Carolina Esso no. 1 well at Cape Hatteras; 

it thins to 28 feet on the west side of Pamlico Sound in 

Carolina Petroleum Co.'s no. 1 Atlas Plywood well, and 

was not observed in the records of wells farther updip. 

Paleocene deposits have not been recognized at the 

surface in North Carolina or in neighboring States.

The assignment to the Paleocene (?) is based on the 

lithologic similarity to the Clayton formation of Georgia (Cooke, 1943, pp. 39-47) and not on paleontologic 

evidence. The sequence in the Hatteras Light well no. 

1 and North Carolina Esso well no. 2 consists of finegrained light gray, glauconitic, highly siliceous, sandy 

shale and marl below, and fine-grained sandstone above. 

Montmorillonite is the principal clay constituent of 

core samples from the unit according to Dr. S. S. Goldich (personal communication) who kindly examined 

the samples.

The underlying Upper Cretaceous rocks also are 

highly siliceous, but coarser-grained, with more coarsegrained glauconite, and contain a distinctive Later Cretaceous fauna.

FIGURE 2.—Stratigraphic relationships of Cenozoic rocks in Esso Standard Oil Company Hatteras Light well no. 1 and North Carolina Esso 

well no. 2, eastern Dare County, N. C.

Esso Standard Oil Co., 

North Carolina, 

Esso Well No. 2

Esso Standard Oil Co,

Hatteras Light

Well No. i

Total depth 6,410 feet \ \

/ bottom in. \ v \

( Lower Cretaceous^ \ v

\\\

Shale Sandy shale Chert No record
6 OSTRACODA FROM WELLS IN NORTH CAROLINA

Brachycythere cf. B. hadleyi Stephenson is the only 

species of ostracode obtained from the Paleocene (?), 

and the specimens may have fallen from higher levels. 

Other fossils are scarce; there are tiny Globigerina, and 

calcareous, benthonic Foraminifera in core samples 

from the unit. A radiolarian and a possible diatom 

were seen in thin section.

Rocks assigned to the Paleocene (?) in the Hatteras 

Light well no. 1, and the North Carolina Esso well no. 

2 are described on pages 11 and 12.

EOCENE SERIES 

LOWER EOCENE

The lower Eocene is 485 feet thick in the Hatteras 

Light well no. 1, 301 feet thick in the North Carolina 

Esso well no. 2, and 80 to 253 feet thick in the deep wells 

on the west side of Pamlico Sound.

The lower part of the subsurface Eocene at Cape 

Hatteras and southwestward to Carteret County consists of fine-grained glauconitic sandstone and sandy 

limestone in which many of the layers are highly silicified. Beds of glauconitic, light-gray, translucent chert 

occur at several levels. In the North Carolina Esso 

•no. 2 well, 32 miles north of Cape Hatteras, only the 

lower beds of the equivalent unit are highly silicified; 

the remainder consists of brownish-gray, argillaceous, 

fine and medium grained sandstones and fossiliferous 

limestones. Coarse grained conglomeratic sandstone 

with pebbles of amethyst and other varieties of quartz 

occurs at the base of the unit in the North Carolina Esso 

well no. 2.

The lower Eocene of this paper perhaps is a correlative of the Black Mingo formation of South Carolina 

and of the Aquia formation of Maryland, Delaware, and 

Virginia both of Wilcox age, but from Cape Hatteras 

southwestward, in the wells studied here, lithologically 

it resembles the McBean formation of South Carolina 

which is of Claiborne age.

Most of the ostracode species, however, provide a correlation with the Wilcox group of the Gulf region or 

with the Aquia formation of the middle Atlantic states 

(Howe and Garrett, 1934, Schmidt, 1948). Trachyleberis davidwhitei and Bmchycythere hadleyi have 

heretofore been reported only from the Claiborne group 

(Stephenson, 1946, pp. 333, 336, 340, and Howe and 

Chambers, 1935).

The ostracodes of the Black Mingo formation are 

unknown to the writer. Detailed descriptions of the 

lower Eocene in the Hatteras Light well no. 1, and the 

North Carilina Esso well no. 2, are given on pages 

11 and 12.

EOCENE (AND UPPER EOCENE (?))

The coarse, porous, fossiliferous, sandy, glauconitic 

limestones and calcareous sandstones that overlie the 

lower Eocene in the subsurface of eastern North Carolina contain many species of ostracodes that are characteristic of the Claiborne group.

The unit is 647 feet thick in the Hatteras Light well 

no. 1 at Cape Hatteras; it thins to 80 feet on the west 

side of Pamlico Sound in North Carolina Petroleum Co. 

no. 1 Atlas Plywood well.

The middle Eocene of this paper probably represents 

the beds that were recorded by Mundorff (1944) as 

Castle Hayne marl in various water wells in eastern 

North Carolina. The Castle Hayne of surface exposures is basal upper Eocene and is correlated with 

the Ocala limestone of Florida (Kellum, 1926). The 

strong Claiborne aspect of the ostracodes in the subsurface unit and the lack of knowledge of ostracodes in 

the surface exposures, prevent a correlation with the 

surface Castle Hayne but suggest correlation with the 

McBean formation of Georgia and South Carolina. 

Martin (1939) described species of Cytheropteron from 

the McBean that occur in the Claiborne group of the 

central Gulf region. A sample from the so-called 

McBean at Orangeburg, S. C. yielded a few specimens 

of Haplocytheridea montffomeryensis (Howe and 

Chambers). This species ranges from the middle 

Eocene (Claiborne) to Oligocene (Vicksburg) in the 

Gulf region, but has not been found in lower Eocene 

rocks. The only ostracodes from surface exposures of 

the Castle Hayne in the writer's possession are specimens of Leguxminocythereis scardbaeus Howe and Law, 

obtained by Mr. Mundorff from Pollacksville, N. C. 

This species has been recorded previously only from the 

Vicksburg group, Oligocene of Louisiana (Howe and 

Law, 1936, p. 64).

The author found no ostracode faunas of late Eocene 

age in the samples from eastern North Carolina wells. 

Available evidence indicates that the middle and upper 

Eocene are not distinguishable on the basis of the ostracode faunas, at least in this area.

No definite conclusions concerning the stratigraphic 

relationships of the various subsurface early and middle 

Tertiary ostracodes are possible until the faunas of surface rocks are better known.

OLIGOCENE OB, LOWER. PART OF MIOCENE SERIES

Overlying the middle (or upper?) Eocene in the Hatteras Light well no. 1, and the North Carolina Esso 

well no. 2 is a sequence of sandstone, glauconitic shale, 

and porous sandy limestone, of undetermined but apparently postmiddle Eocene age. The unit is 258 feet
CENOZOIC OSTRACODA

thick in the Hatteras light well no. 1 and 160 feet thick 

in the North Carolina Esso well no. 2. It has not been 

definitely identified in the other wells studied.

An Oligocene age for part or all of the unit is indicated by the presence of Cytfaeretta howei Swain (1946, 

p. 380), a species that occurs in the subsurface Oligocene 

of Florida.2 Haplocytheridea israelslcyi Stephenson, to 

which one of the species is related, occurs in the subsurface middle Tertiary of Texas (Stephenson, 1944a, 

pp. 156-161) in beds which are possibly of Oligocene 

age, but ranges into the Miocene judging from an occurrence in the subsurface of Maryland (Swain, 1948, 

p. 210). The other species indicate a Miocene age for 

the containing strata.

MIOCENE SERIES

Lower part.—Strata tentatively identified as lower 

Miocene are present in the wells at Cape Hatteras and 

southwest. They are porous, sandy, nonglauconitic 

limestone and cleanly washed, water-polished sand up 

to 485 feet thick. On the basis of lithology, this unit is 

believed to represent the Trent marl as exposed at the 

surface in North Carolina.3 North of Cape Hatteras 

a facies change takes place and in the North Carolina 

Esso well no. 2 what is apparently the same stratigraphic interval is occupied by soft, light-gray, sandy 

shale, 465 feet thick, which contains diatoms. The 

shale has not been identified in the surface exposures 

but is here considered to be at least partly equivalent in 

age to the Trent. Lithologically similar deposits occur in the Calvert formation of middle Miocene age, 

in the middle Atlantic states, and may in part be of the 

same age as the shales under discussion.

Middle part.—The fine grained, argillaceous, f ossiliferous sands and sandy clays that overlie the Trent marl 

in the Hatteras Light well no. 1 are here placed in the 

middle part of the Miocene. The ostracode Trachyleberis evax (Ulrich and Bassler) does not range into the

2 C. W. Cooke questions assignment of the unit to the Oligocene, because (written communication, August 8, 1949) "No Oligocene deposits 

are known at the surface east of the valley of Savannah River." F. S. 

MacNeil (written communication, February 17, 1950) agrees as to the 

possibility that the Oligocene is represented by sedimentary deposits in 

the subsurface of eastern North Carolina. Both Cooke and MacNeil 

suggest that the unit in question may be equivalent to the Trent marl 

of early Miocene age.

3 C. W. Cooke (written communication, August 8, 1949) states: "I 

suspect that the upper part of this interval is middle Miocene, equivalent 

to part of the Chesapeake group of Maryland. No lower Miocene affinities are suggested by the fauna, but the presence of pebbles between 

1,120 and 1,180 feet in the Hatteras Light no. 1 suggests the base of a 

formation. Perhaps the Trent (lower Miocene) extends only up to 

1,180 feet." The coarse deposits indicate a local change in sedimentologic conditions but no widespread or important environmental change. 

The pebbly unit cannot be distinguished from the adjacent units by 

electrical characteristics (see fig. 2), and it would be difficult to justify 

placing a stratigraphic boundary at 1,180 feet.

overlying strata in this well, and in other parts of the 

region has not been found in the upper Miocene. In 

Maryland it occurs in the Calvert formation of middle 

Miocene age. In the Hatteras Light well no. 1 the unit 

is 250 feet thick; in the Esso no. 2 well it is 340 feet 

thick, contains abundant shell fragments, and its sands 

are coarser grained than in the Hatteras Light well no. 

1. The St. Marys formation of surface exposures in 

North Carolina probably is equivalent to the subsurface middle Miocene of this paper, but the exact correlation is uncertain.

Upper part.—The upper Miocene in the Hatteras 

Light well no. 1, and the North Carolina Esso well no. 2 

consists of poorly cemented sand and shell beds. The 

upper part of the unit consists of shell beds and probably represents a thick deposit of the Duplin marl. 

The upper Miocene of the wells is probably the equivalent of the Yorktown formation as exposed at the surface in the North Carolina coastal plain. In the Hatteras Light well no. 1 the unit is 560 feet thick,4 and in 

the no. 2 well, 230 feet thick. Upper Miocene mollusks 

from beds at depths of 160 to 640 feet in the no. 1 well 

were identified by Julia Gardner.

PLIOCENE SERIES

Only Hatteras Light no. 1 well furnishes information on the subsurface Pliocene. The mollusks occurring at depths of 120 to 160 feet suggest a Pliocene age, 

according to Gardner (1948). The drill cuttings from 

this unit are mostly casing cement but at depths of 130 

to 140 feet loose sand and abundant mollusk fragments 

were obtained, but no ostracodes.

PLEISTOCENE SERIES

Miss Gardner suggested (1948) that the beds 40 to 

120 feet below the surface in the Hatteras Light well 

no. 1 may be of Pleistocene age. The deposits are fineto coarse-grained, unconsolidated sand, contain shell 

fragments, and are conglomeratic in the lower 40 feet. 

Pleistocene deposits were not recognized in the other 

wells.

Nearly all of the ostracodes from 60 to 110 feet depth 

in the Hatteras Light well no. 1 are of species previously 

found only in the Miocene, and may represent reworked 

specimens.

4 C. W. Cooke (written communication, August 8, 1949), believes 

that the base of the upper Miocene in the Hatteras Light well, no. 1 

is at 290 feet because there is a gravel bed above that horizon and 

because he feels that the molluscan evidence suggesting late Miocene 

age below that level is "very inconclusive." Julia Gardner (written 

communication, March 26, 1948) identified Mulinia- congesta Conrad 

from a depth of 570-580 feet in the Hatteras Light well no. 1 and 

stated that it "is highly characteristic of a certain zone in the upper 

Miocene of Virginia and North Carolina."
OSTRACODA FROM WELLS IN NORTH CAROLINA

RECENT SERIES

Forty to 50 feet of fine- to coarse-grained, unconsolidated sand at the top of the section in the Hatteras 

Light well no. 1 is of Recent age, according to Miss 

Gardner. No ostracodes were found in samples from 

this unit.

MOLLUSKS FROM THE ESSO STANDARD OIL CO. 

HATTERAS LIGHT WELL NO. 1

Julia A. Gardner kindly identified macrofossils from 

depths of 18 to 1,100 feet in the Hatteras Light well no. 

1 near Cape Hatteras, N. C. Her report concerning 

the age relationships of the fauna follows.

"No fauna older than the upper Miocene is clearly recorded 

in the cuttings from Hatteras Light well no. 1.

"The uppermost 40' yielded only a few fragments of echinoids 

and broken shells, for the most part Mulinia. Those upper 

sands may be Recent, Pleistocene, or even, though not probably, 

Pliocene. A slight change in the fauna at about 120' is indicated by a greater diversity rather than by the appearance in 

the fauna of any Pliocene zone markers. It is possible that the 

upper 120' may be Quaternary, and those from 120' to 160' 

may be referable to the Pliocene. The cuttings from 160' to 

170' contain a more diversified fauna than any of those higher 

in the well, and among the species is Crassinella sp. cf. (7. 

dupliniana Dall, a form not established in beds younger than 

the Miocene. The faunas between 160' and 250' are the richest 

in the section. They are closely allied to those from the Duplin 

surface outcrops, though they show no marked resemblance 

to those from the Havelock well. Below 250' the faunas are 

rather meager, but no new significant forms appear. Limestone molds of small but undeterminate shells were recovered 

from 350' to 360', but Astarte (AsJitarotha) ooncentrica Conrad, 

present throughout the Miocene and Pliocene of Virginia and 

North Carolina though most abundant in the Yorktown, is unmistakably present and probably in place at 630' to 640'. Below this depth nothing is found on which an age determination 

can be based."

STRATIGRAPHY OF WATER WELLS IN EASTERN 

NORTH CAROLINA

An unpublished report by Joseph A. Cushman, dated 

April 24, 1946, here summarized, provided the following information:

1. Edentoii Naval Air Base well no. 1, Chowan 

County, N. C., 22-25 feet, Miocene.

2. Edenton Naval Air Base well no. 4, Chowan 

County, N. C., 40-88 feet, Miocene.

8. Williamson test well no. 2, Martin County, N. C., 

88-95 feet, Miocene.

4. W. H. A. well no. 2, Wilmington, New Hanover 

County, N. C., 132-157 feet, specimens of Foraminifera few and poorly preserved, probably Miocene (?).

5. Bogue well no. 65, Carteret County, N. C., 80-230 

feet, Miocene. 230-245 feet, very few specimens 

of Foraminifera, Eocene (?).

6. Layne Housing Project well, Jacksonville, Onslow 

County, N. C., 53-132 feet, specimens of Foraminifera few and poorly preserved, presumably 

Miocene.

7. Jacksonville Tent Camp well no. 2, Onslow County, 

N. C.

10-20 feet, indeterminate. 

105-110 feet, Eocene(?). 

110-120 feet, indeterminate. 

120-130 feet, Eocene.

8. Winton well, Hartford County, N. C., 116-148 feet, 

probably Miocene. 160-162 feet, few but distinctive Foraminif era; probably Eocene, but not like 

the Eocene of the other wells.

9. Harvey Neck well, Perquimans County, N. C., 43- 

74 feet, probably Miocene.

10. Cape Lookout well, Carteret County, N. C., 

75-101 feet, Miocene. 

101-125 feet, indeterminable. 

203-235 feet, apparently Eocene, Jackson

group. 

408-415 feet, Eocene, Claiborne (?) group.

11. Naval Auxiliary Air Station well, Washington, 

Beaufort County, N. C. 

60-75 feet, Miocene. 

90 feet, Eocene: Asterigerina sp. Textularia

dibollensis, Cancris cubensis. 

120 feet, Eocene. 

125 feet, Eocene, very few specimens of Foraminifera. 

130-165 feet, Eocene, some species similar to

species of McBean or Lisbon age. 

190 feet, indeterminable. 

195 feet, a few species of Foraminif era present,

related to Paleocene Midway group.

CENOZOIC ROCKS IN ESSO STANDARD OIL CO. 

HATTERAS LIGHT WELL NO. 1

ThickDepth ness 

Lithology (feet) (feet)

Recent

No record of cuttings______-___________-___ 0-18 18

Sand, fine- to very coarse-grained, angular to 

sub-rounded, containing abundant shell fragments, conglomeratic in lower part-________ 50 32

Pleistocene

Sand, white, fine-grained at top, coarse and 

conglomeratic below, angular to subrounded, 

very fossiliferous, and with several shell 

beds in lower part__-_--__--__---_-_----_ 120 88
CENOZOIC OSTRACODA

ThickDepth ness 

Lithology (feet) (feet)

Pliocene

No record of cuttings, a few mollusks of Pliocene age according to Miss Gardner._______ 150 30

Shell bed, sandy, with abundant mollusks _____ 160 10 

Upper Miocene

Sand, fine- to coarse-grained, angular to

rounded, with abundant mollusks________ 185 25

Shell bed, and sand, containing mollusks and

Foraminifera___-_----____ ______________ 225 40

Sand, fine- to coarse-grained, argillaceous 

in middle part, conglomeratic with ferruginous, varicolored quartz, sandstone, and 

quartzite pebbles in lower 30 feet; abundant 

Foraminifera, mollusks, and ostracodes 5__._ 290 65

Coquinoid limestone, white and light-gray, 

very porous, partly sandy, more consolidated than shell beds above, containing 

drusy cavities; fauna mostly mollusks ______ 310 20

Sand, very fine- to medium-grained, angular 

to subrounded, cleanly washed, water 

polished___________________________ 320 10

Foraminiferal coquina, white and light brown,

partly argillaceous and sandy, porous_____ 340 20

Sand, fine- to medium-grained, angular to

subrounded, water polished._____________ 350 10

Coquinoid limestone, white and light-gray, 

partly sandy and argillaceous, with abundant mollusks, Foraminifera and echinoid 

fragments. Core 346-356 feet, recovered 4 

inches of light-gray, very porous, sandy, 

coquinoid limestone. Core 480-490 feet, 

recovered 5 feet of light-gray to white, argillaceous, marly* fine- to coarse-grained sandstone; sp. gr. ranges from 1.86 to 2.03.6 

Core 540-550 feet, recovered 10 feet of lightgray and white, sandy marl and chalk; sp. 

gr. ranges from 1.81 to 1.88______________ 555 205

Clay, light-gray and brown, with abundant

Foraminifera- _---__--_--_-_____________ 575 20

Sand, fine- to coarse-grained, partly argillaceous; contains mollusks, abundant Foraminifera and ostracodes. Core 600-610 feet, 

recovered 20 inches of light-gray, fine- to 

medium coarse-grained, very argillaceous, 

calcareous sand; sp. gr. 1.95. Core 650-660 

feet, recovered 4 feet of gray, fine- to medium-grained, fairly porous, soft, argillaceous 

sand, with abundant disseminated pyrite; 

sp. gr. ranges from 1.74 to 1.79. Core 700- 

710 feet, recovered 20 inches of light-gray, 

fine- to medium coarse-grained, porous, 

argillaceous, silty, slightly glauconitic sand 

with dark chert or quartz grains; sp. gr. 1.70_ 710 135

Limestone, white and light-gray, coarsely 

crystalline, porous, argillaceous, containing 

abundant Foraminifera-_________________ 720 10

' See footnote, p. 12.

4 Specific gravity determinations of core samples were provided 

by the Esso Standard Oil Co.

Lithology 

Middle Miocene

Sand, fine- to coarse-grained, calcareous, partly 

argillaceous, slightly glauconitic in upper 

part, containing abundant Foraminifera; 

Trachyleberis evax (Ulrich and Bassler) 730- 

740 feet. __-_----__--__---------__ _ __

Sand, fine- to medium coarse-grained, very 

argillaceous, containing abundant Globigerina. Core 760-770 feet, recovered 3 feet 4 

inches of light-gray, fine- to mediumgrained, argillaceous, calcareous sand with 

abundant Globigerina; sp. gr. ranges from 

1.82 to 1.86. Core 810-820 feet, recovered 

6 feet of light-gray, soft, sandy marl and 

calcareous sand, with abundant Globigerina; 

sp. gr. range from 1.42 to 1.53 _ _________

Clay, light gray-brown, slightly sandy, abundant Globigerina ________________________

Sand, very fine- to coarse-grained, scattered 

glauconite in middle part, more abundant 

glauconite in lower part. Core 880-890 

feet, recovered 3 feet of light-gray, finegrained, calcareous, fairly porous sand with 

abundant Globigerina; sp. gr. 1.66. Core 

940-950 feet, recovered 10 feet of light-gray, 

firm, calcareous, porous sandstone with 

abundant Globigerina; sp. gr. ranges from 

1.61 to 1.63____ _ _____________________

Lower Miocene

Limestone, white, chalky to coarsely crystalline, porous, fossiliferous. Core 1,010- 

1,020 feet recovered 12 inches of light-gray 

and white chalky limestone and marl, 

containing abundant broken, recrystallized 

shell fragments and Foraminifera; sp. gr.

ThickDepth ness 

(feet) (feet)

745 25

820 75

850 30

995 145

Sand, coarse-grained, rounded, water polished.

Limestone, white, porous, partly recrystallized, 

with intercalated sand and claybeds, 

bryozoans _____--________-___--________-

Sand, very fine- to coarse-grained, water polished, containing Foraminifera__ _________

Limestone, white and light-gray, finely to 

coarsely crystalline, in part coarsely sandy, 

fossiliferous; containing fragments of gray 

and brown chert and metamorphic rock; 

much of limestone presents a detrital appearance; Globigerina abundant at several horizons __ ___ ____j --_-_______--_-___-__-_

Sand, fine- to coarse-grained, water polished __

Limestone, light-gray and white, porous, recrystallized, possibly detrital, partly sandy, 

fossiliferous, with an abundance of flat shell 

fragments in lower part___ _ ______________

Clay, light gray, sandy, containing abundant 

Foraminifera_ __________________________

Limestone, white and light-gray, porous, in 

large part detrital, partly sandy, fossiliferous, containing brown phosphatic pellets 

at top __---_-_-___-__-___---_--__----__

1, 030 35

1, 070 40

1, 100 30

1, 120 20

1, 180 60

1,200 20

1,270 70

1,290 20

1, 330 40
10 OSTRACODA FROM WELLS IN NORTH CAROLINA

Lithology 

Lower Miocene—Continued

Sand, coarse-grained, clear, water-polished. __

Limestone, white and light-gray, coarsely 

crystalline, partly detrital, porous, sandy. 

Core 1,407-1,412 feet, recovered 10 inches 

of white sandy chalk, quartz grains well 

rounded _______________________________

Sand, fine- to coarse-grained, water-polished, 

containing smoky, rose, and amethystine 

quartz, chert, and rock fragments. Core 

1,465-1,475 feet, coarsely sandy white chalk, 

sp. gr. 2.28__--_____--._______________

Lower Miocene or Oligocene (possibly including 

upper Eocene equivalents in lower part)

Limestone, white, and light-brown, porous, 

sandy, partly detrital. Core 1,525-1,535 

feet, recovered 33 inches of white coarsely 

sandy chalk, quartz grains well rounded; 

sp. gr. 2.24___________________________

Sand, coarse-grained, angular to subrounded. 

Core 1,587-1,597 feet, recovered 26 inches 

of light-gray, fine- to coarse-grained, subrounded, calcareous, argillaceous, fairly porous, very glauconitic sand, partly speckled 

with spots of limonite; sp. gr. 2.10__-____-

Limestone, white, porous, recrystallized, abundantly f ossiliferous_ _____________________

Clay, buff, sandy, glauconitic, with interbeds 

of coarse-grained glauconitic sand, and 

sandy limestone. Core 1,650-1,660 feet, 

recovered 40 inches; top 20 inches very 

light-gray, sandy, glauconitic marl with 

brown phosphatic pellets; bottom 20 inches 

fine- to coarse-grained angular to subrounded, calcareous, fairly porous greensand; sp. gr. 2.09. Core 1,680-1,690 feet, 

recovered 3 feet of green, very sandy 

glauconitic clay and argillaceous sandstone; 

sp. gr. 2.11_____________________________

Middle Eocene (possibly including upper Eocene 

equivalents in upper part):

Sandstone, fine-grained above, coarser below, 

angular, porous, calcareous, glauconitic, fossiliferous. Core 1,740-1,750 feet recovered 

10 feet of very light-gray, firm, finely sandy 

siltstone; sp. gr. ranges from 2.05 to 2.14__

Limestone, white and light-gray, sandy, porous, recrystallized, glauconitic, fossiliferous 

at several horizons. Core 1,800-1,810 feet, 

recovered 2 feet of white, porous, chalky, 

very fossiliferous, glauconitic limestone; sp. 

gr. 1.91. Core 1,860-1,870, recovered 4 

inches of white, porous, sandy, coquinoid 

limestone. Core 1,920-1,930 feet, recovered 

6 inches of white, soft, very sandy slightly 

porous chalk. Core 1,983-1,993 feet, recovered 14 inches of white, soft, very sandy 

chalk having low porosity; sp. gr. 2.20. 

Core 2,043-2,053 feet, recovered 6 inches of 

white, soft, sandy chalk, low porosity. 

Core 2,083-2,093 feet, recovered 3 feet of 

white, soft, slightly sandy chalk, low porosity; sp. gr. 1.91______________________

ThickDepth ness 

(feet) (feet)

1, 350 20

1,450 100

1, 480 30

1,550 70

1, 600 50

1,610 10

1, 738 128

1, 780 42

2, 120 340

Lithology 

Middle Eocene—Continued

Sandstone, light-gray and white, fine-grained, 

argillaceous, and interbedded white, sandy, 

chalky limestone. Core 2,135-2,145 feet, 

recovered 6 feet of white, soft, sandy, 

glauconitic chalk; sp. gr. ranges from 1.92 to 

2.04_________________________________

Limestone, light gray and white, sandy_ ______

Sandstone, fine- to coarse-grained, calcareous 

and glauconitic in lower part. Core 2,196- 

2,206 feet, recovered 2 feet of light greenishgray, porous, fine-grained, subangular, 

fossiliferous, glauconitic sandstone; sp. gr. 

2.30_________________________________

Limestone, white, coarsely crystalline, porous, 

sandy, fossiliferous, glauconitic; and interbedded sandstone. Core 2,257-2,267 feet, 

recovered 26 inches of light greenish-gray, 

fine-grained, calcareous, fossiliferous, glauconitic sandstone; sp. gr. 1.91. Core 2,309- 

2,319 feet, recovered 8 feet of white and 

greenish-gray, fine- to medium-grained, 

subangular to subrounded, fairly porous, 

very glauconitic, fossiliferous sandstone; 

sp. gr. ranges from 1.95 to 2.01__________

Lower Eocene

Sandstone, fine- to coarse-grained, argillaceous, 

and interbedded light brown, argillaceous, 

sandy, fossiliferous limestone, containing 

phosphatic pellets, and nodules of gray 

chert. Core 2,380-2,390 feet, light-gray, 

fine- to medium-grained, subangular to subrounded, porous, glauconitic, silty,. fossiliferous sandstone;'sp. gr. 2.21. Core 2,441- 

2,451 feet, recovered 3 feet of very lightgray, very fine- to medium-grained, angular, 

silty, glauconitic sandstone with laminae of 

glauconitic chert; sp. gr. 1.84____________

Limestone, white, dense, sandy, glauconitic 

and interbedded white, sandy glauconitic 

chert. Core 2,460-2,470 feet, recovered 2 

feet of white, siliceous, calcareous, slightly 

porous, glauconitic sandstone, and glauconitic chert; sp. gr. 1.96__________________

Sandstone, white, fine-grained, calcareous, glauconitic, and interbedded glauconitic, sandy 

chert. Core 2,531-2,541 feet, recovered 5 

feet of light greenish-gray, soft, very fine- to 

fine-grained, angular, micaceous, glauconitic, calcareous, soft, slightly porous sandstone; sp. gr. ranges from 1.73 to 1.74__.__

Limestone, white, dense, sandy, glauconitic, 

interbedded with white glauconitic chert and 

fine-grained sandstone. Core 2,593-2,^03 

feet, recovered 18 inches of light-gray, very 

fine- to fine-grained, angular, micaceous, 

glauconitic, calcareous, soft, slightly porous 

sandstone; sp. gr. 1.67___________.-_______

Sandstone, white, fine-grained, calcareous, 

glauconitic, slightly argillaceous, and interbedded with white glauconitic chert__-___-

ThickDepth ness 

(feet) (feet)

2, 150

2, 180

30

30

2,230 50

2, 385 155

2,460 75

2, 500 40

2,560 60

2, 610 50

2, 630 20
CENOZOIC OSTRACODA 11

ThickDepth ness 

Lithology (feet) (feet)

Lower Eocene—Continued

Limestone, white, glauconitic, sandy, chalky, 

and interbedded white glauconitic chert. 

Core 2,653-2,663 feet, recovered 3 feet 6 

inches of light gray, very fine- to finegrained, angular, calcareous, glauconitic, 

micaceous, siliceous sandstone; sp. gr. 2.14_ 2, 670 40

Sandstone, chert, and limestone, interbedded, 

white and light-gray, glauconitic. Core 

2,714-2,724 feet, recovered 10 feet of lightgray, sandy, glauconitic, micaceous, slightly 

calcareous, highly siliceous shale; sp. gr. 

ranges from 1.76 to 1.91-__--_-_-_________ 2,730 60

Sandstone, light-gray and white, argillaceous,

glauconitic, fairly porous_______________ 2,755 25

Limestone, white, partly chalky-textured, 

finely glauconitic, sandy, interbedded with 

light-gray and white, very siliceous, glauconitic shale and chert; lower part more 

shaly and apparently gradational with underlying unit. Core 2,775-2,785 feet, recovered 7 feet 8 inches of light-gray, compact finely glauconitic, micaceous, irregularly laminated, slightly calcareous, highly 

siliceous shale; sp. gr. ranges from 1.83 to 

1.88. Core 2,835-2,845 feet, recovered 10 

feet of white, slightly porous, slightly calcareous, finely sandy, glauconitic chert containing impressions of small pteropod? 

shells; sp. gr. ranges from 1.79 to 1.82.___ 2, 870 115 

Paleocene(?)

Shale, light-gray and white, highly siliceous, 

finely glauconitic, slightly calcareous. Core 

2,897-2,907 feet, recovered 8 feet of very 

light-gray, compact, very finely glauconitic, 

micaceous, siliceous shale; sp. gr. ranges 

from 1.89 to 1.96. Core 2,950-2,960 feet, 

recovered 9 feet 6 inches of white, compact, 

slightly calcareous, finely glauconitic, micaceous, highly siliceous shale; sp. gr. ranges 

from 1.93 to 2.30__._______________ 3,033 160

Upper Cretaceous (uppermost beds)

Sandstone, white, fine-grained, slightly porous, 

in part indurated by siliceous cement, more 

coarsely glauconitic than overlying Paleocene?; interbeds of sandy, partly calcareous, 

siliceous shale and chert. Core 3,060-3,070 

feet, recovered 30 inches of white, slightly 

calcareous, finely glauconitic, highly siliceous shale_______________________ 3,080 47

Bottom of well in pre-cambrian granite______10, 054

TERTIARY ROCKS IN ESSO STANDARD OIL CO. 

NORTH CAROLINA ESSO WELL NO. 2

Depth Lithology 

No record of drill-cuttings_________________ 0-100

Pliocene (?)

Sand, fine- to coarse-grained, unconsolidated, 

argillaceous, slightly glauconitic; few Foraminif era _______________________________ 160

No record of drill-cuttings _________________ 230

Thickness 

(feet)

100

60

70

Lithology 

Upper Miocene

Sand, fine- to coarse-grained, unconsolidated, 

angular to subrounded, partly argillaceous 

and yellowish-brown, trace of glauconite in 

lower part; abundant mollusk shells throughout, Foraminifera in lower part-___________

Clay, light-gray, soft; containing Foraminif era_ _________________-__--_---_--__-__

Sand, fine- to coarse-grained, conglomeratic, 

clean, water-polished and glauconitic in 

lower part; abundant Foraminif era, mollusk 

shells and ostracodes 7___________________

Sand and molluscan shell beds, shells more 

chalky in texture (perhaps an effect of diagenesis) in lower part, abundant Foraminifera throughout_______________________

Shale, light-gray, very sandy, glauconitic, and 

fine- to medium-grained, soft, argillaceous 

sand; large thick-shelled mollusks in lower 

part_________-______-____--_-_-_____-

Limestone coquina, light-gray, partly sandy, 

very porous, largely composed of recrystallized fragments of mollusks ______________

Middle Miocene

Sand and shell beds, coarse grains of quartz, 

large mollusk fragments.________________

Sand, fine- to medium-grained, partly well 

rounded and water-polished; fragmentary 

mollusk shells very abundant at several 

levels, large Foraminif era 540-550 feet_____

Gravel bed, quartz pebbles, containing mollusk 

shells. ____________-____-_____-_--__-_-_

Limestone, light-brown, finely crystalline, 

sandy _________________________________

Gravel beds and sand; well-rounded quartz 

pebbles; large, thick mollusk fragments, 

shark tooth ____________________________

Lower Miocene?

Shale, light-gray and brown, finely sandy, and 

interbedded fine- to coarse-grained, unconsolidated sands, diatoms at many levels, Foraminifera numerous below 1,070 feet._____ 

Oligocene or Lower Miocene (possibly including 

upper Eocene equivalents in lower part)

Sand, fine- to coarse-grained, unconsolidated, 

subangular to subrounded; containing abundant brown phosphatic nodules and fish 

bones from 1,265-1,310 feet; a conglomeratic 

layer partly cemented by brown carbonate 

from 1,320-1,330 feet; abundant fine- to 

coarse-grained, dark-green glauconite from 

1,350-1,380 feet; a few mollusks in lower 

part_ ______-________-_--_-_----_------_

Shale, soft, brown; and interbedded sand____ 

Middle Eocene (possibly including upper Eocene 

beds in upper part)

Limestone, white, porous, glauconitic, sandy; 

sand fine- to coarse-grained, rounded; mollusks, bryozoans, ostracodes, Foraminif era--

Depth 

(feet)

Thickness 

(feet)

256

280

310

26

24

30

410 100

430

460

490

660

700

720

20

30

30

170

40

20

800 80

1,^65 465

1,380

1,425

115

45

1, 580 155

7 C. W. Oooke (written communication August 8,1949) believes that the base of the 

Duplin marl may be at 310 feet.
12 OSTRACODA FROM WELLS IN NORTH CAROLINA

ThickDepth ness 

Lithology (feet) (feet)

Middle Eocene—Continued

Sand, coarse-grained, unconsolidated, angular

to subrounded________________________ 1,600 20

Marl, light-gray, soft, partly sandy, fossiliferous______--_--_--_-_-_--__-_----___ 1,625 25

Sand, fine-grained, cleanly washed, waterpolished, subrounded, glauconitic _.-__-__- 1,650 25 

Limestone, white, fairly porous, chalky, and 

finely to coarsely crystalline, sandy, glauconitic; middle and lower parts contain very 

coarse sand grains. _____________________ 1,735 85

Lower Eocene

Sandstone, fine- to coarse-grained, glauconitic

and white, sandy, porous limestone- ______ 1, 930 195

Depth 

Lithology (feet)

Lower Eocene—Continued

Sandstone, fine-grained, argillaceous, glauconitic, containing layers with siliceous 

cement below 1,940 feet. __________------ 1,955

Limesone, light-tan, finely crystalline to

chalky, glauconitic, partly siliceous._ — ___ 1, 965 

Conglomerate, slightly ferruginous, rounded

quartz grains, some amethystine quartz__ 2, 036 

Paleocene(?)

Shale, light-gray to white, siliceous, finely 

glauconitic, with layers of glauconitic chert; 

calcareous in upper and lower portions _ _ _ _ 2, 225

Upper Cretaceous (uppermost beds)

Sandstone, greenish-gray, coarse-grained, very

argillaceous, coarsely glauconitic, sideritic__ 2, 250 

Bottom of well in Lower Cretaceous__-__-__-____ 6, 410

Thickness 

(feet)

25

10

71

189

25

Stratigraphic ranges of ostracode species from wells in North Carolina, and previously reported occurrences

[In this table the figures indicate the occurrence of the species in localities listed on p. 3 and X the occurrence of the species elsewhere. For example, Prachycythere cf. B. 

hadleyi is recorded from the Paleocene, Lower and Middle Eocene in well 2, and from the Middle Eocene in well 1]

Acuticythereis cf. A. laevissima Edwards. 

laevissima punctata Edwards. _ __ _

cf. A. multipunctata Edwards....

Bairdia sp _______ __ _ _ __________

cf. B. laevicula Edwards. _. __ _ __

cf . B. fortificata Brady _ _______ ___

Bairdoppilata cf. B. delicatula Jennings _ _

Basslerites cf. B. miocenicus (Howe)

cf. B. giganticus Edwards. ________

Brachycythere marylandica (Ulrich) ____

cf. B. jessupensis Howe and Garrettcf. B. hadleyi Stephenson ____

cf. B. martini Murray and Hussey__

sp ——— _--_-__-._______ — _____

Buntonia howei (Stephenson) _ _ _ _

? mcguirti (Howe) __ ___ ___ __ _

? cf. B.I lacunosa (Jones) _ __ ____

? cf. B.I garretti (Howe and McGuirt). 

? planibasilis (Ulrich and Bassler) _

Bythocypris cf. B. parilis Ulrich. __ ____

? wicomicoensis Swain ___ __ __

Caudites jacksonvillensis Swain, n. sp_ __

Clithrocytheridea sp _______ __ _

cf. C.'broussardi Howe and Garrett__

virginica Schmidt ___ _ __ _ __

cf. C. smithvillensis Stephenson- ____

cf. C. caldwellensis (Howe and 

Chambers) . 

Cytherella cf. C. marlboroensis Ulrich_ ___

sp — -____-__-_.___ _ _ _ ______

cf. C. hannai Howe and Lea____ ___

sp___ —— __________ _ — _ —— ____

Cytherelloidea howei Swain __ __ ____ __

sp._ -__ _______ ____ ______ ___

Cytheretta darensis Swain, n. sp___ _ __

cf. C. alexanderi Howe and Chambers 

porcella (Ulrich and Bassler) __ _ __

karlana Howe and Pyeatt____ __ __

cf. C. bassleri Howe __ _

inaequivalvis (Ulrich and Bassler) _ _ _

cf. C. plebeia (Ulrich and Bassler). __

? sp. aff. C. plebeia (Ulrich and Bassler) ___________________________

Cytheridea sp^ _____

?sp_____________________________

Paleocene

2

Eocene

Lower

1, X

3, X 

X 

2

13, X

1 

X 

X

13, X

3, X

Middle

1

2

3

1,2, X 

2, X

3, X 

3

1

7

3 

3

2, X 

1, X

2

1 

1 

2,3

1

Upper

X

X

X

Oligocene

X

X

Miocene

Lower

1

1 

X

Middle

8

5

6, X

1

X

X

1

X 

8, X 

X 

X 

X

i

Upper

9, X

1, X

X 

4

X 

1, X

1

2, X 

2

1

X 

1 

1,9

3

Pliocene

X

Pleistocene

1

1

Recent

____

X

X

----
CENOZOIC OSTEACODA 13

Stratigraphic ranges of ostracode species from wells in North Carolina, and previously reported occurrences—Continued

Cytherideis ashermani Ulrich and Bassler_

rugipustulosa Edwards_______ _ __

Cytheromorpha cf. C. eocenica Stephenson- 

? sp

warneri Howe and Spurgeon _ ____

curio, Edwards______ _ ________ __

Cytheropteron cf. C. variosum Martin

cf. C. subreticulatum van den Bold. _

sp. (b)___________________________

sp. (a) —————— __ , __ _______

Cytherura sp. aff. C. washburni Stephenson. _. _ _ __ ____ _ _ _______

wardensis Howe and Brown. _______

elongata Edwards __ _ ___ __ ___

forulata Edwards __ ______ ___

reticulata Edwards _______ ___ _ _

Eocytheropteron ? sp_ _ _________ ___

Eucythere cf. E. chickasawhayensis Howe_ 

sp — __ _ — _ — ——— _ ———— _

Favella m.esacostalis Edwards_______ __

Haplocytherideat cf. H.f hopkinsi (Howe 

and Garrett)- _______ _ _ _ _____

cf. H. wallacei (Howe and Garrett)

cf. H. goochi Stephenson _ _ _ _______

sp. aff. H. hammondensis (Swain) ___

cf. H. nowotnyi Stephenson _ _ ____

montgomeryensis (Howe and Chambers). ___ ___ _______

sp. aff. H. israelskyi Stephenson

cf . H. subovata (Ulrich and Bassler) _ 

Hemicythere conradi Howe and McGuirtconfragosa Edwards _

sp. aff. H. conradi Howe and McGuirt 

Leguminocythereis scarabaeus Howe and 

Law __ _____ _ ___ __ ___ ___

whitei Swain, n. sp _ __ _ _ _ ____

clarkana (Ulrich and Bassler) ____ __

Loxoconcha cf. L. creolensis Howe and 

Chambers _______ __ _______ _

sp. aff. L. claibornensis Murray __ __

cf. L. mcbeanensis Murray. ______ _

cf. L. surreala Murray _ ______

subrhomboidea Edwards. _ ____ _ __

cf. L. reticularis Edwards. __ _

edentonensis Swain, n. sp ___ _ ___

Monoceratina cf. harrisi Stephenson

Paracypris cf P. franquesi Howe and 

Chambers__ __________

Paracytheridea? wether ellii ( Jones) __ _ _

nodosa (Ulrich and Bassler) _ ____ _

cf. P. rugosa Edwards _ _____

Pellucistoma cf. P. magniventra Edwards

Pterygocythereis washingtonensis Swain, 

n. sp _ __ _ _____________ _ _ _

cornuta americana Ulrich and Bassler _______________________

Trachyleberisl sp. aff. T.I communis aquia 

(Schmidt) __ _

? bassleri (Ulrich) ____ _____ _

hilgardi (Howe and Garrett) __ ___

? pellucinoda (Swain). ______

davidwhitei (Stadnichenko) _ ______

stenzeli (Stephenson) ___ _ _____ __

mundorffi Swain, n. sp_ ___

pidgeoni (Berry). ____ _ ___

? rukasi (Gooch)_____ _ _ _____

smithvillensis (Button and Williams) _ 

927335 — 52 ——— 2

Paleocene

X

Eocene

Lolrer

1, X 

X 

2, X

2, X

X

1, X

2, X 

X 

1, X 

X

1 1

X

Middle

3, X 

3

3, X

3, X

1, X 

1, X 

1, X 

3

i; 3, x

1, 2, 3, X

3 

3, X 

3, X 

3, X

3, X

X 

X

3

2,3, X 

3 

3 

2,3, X 

1,3, X

3

3, X 

3, X

Upper

X

X

X

X

Oligocene

T

X

i, x

1

X 

2

X

X

Miocene

Lower

1

X

X

1

1

13

1

X

Middle

11, X 

X

1

X

X

5, 11, X

X 

5

5

i,x

5

1,2 

4, X

X

4

Upper

1

1 

2, X

3, X 

3, X

3, X

1

1 

1,4, X 

X

'• X2

1 

1 

1, X

3 

9 

1,2, X 

3, X

2 

9

i, 3, x

1, X

X 

1, X 

2, X

2

3

Pliocene

——

——

——

——

Pleistocene

1

1

1

1

1

Recent

———

———

———

———
14 OSTRACODA FROM WELLS IN NORTH CAROLINA

Stratigraphic ranges of ostracode species from wells in North Carolina, and previously reported occurrences—Continued

Trachyleberis — Continued.

? cf. T.t micula (Ulrieh and Bassler).

? ef . T.? angulata (Sars)__ ._ _ _ _

? cf. T.I reesidei (Swain) __ _____

? cf . T,1 triplistriata (Edwards) _-__

QTk

Paleocene

Eocene

Lower

1 V

Middle Upper

Oligoc|ne

1

Miocene

Lower

1

1 

1

1

Middle

1, X 

8, X 

4, X 

11, X 

1 

X 

8, X 

5

Upper

3, 4, 5, X 

1, 2, 4, 5 

1, 2, 3, 4, 5, X

1 

1,8, X

8 

4, X

1 

2

Pliocene

Pleistocene

X

Recent

X

SYSTEMATIC DESCRIPTIONS

Family CYTHEEELLIDAE Sars, 1866

Genus CYTHEEELLA Jones, 1849

Cytherella cf. C. hannai Howe and Lea s

Plate 1, figure 1

Cytherella hannai Howe and Lea, Howe and Law, 1936, Louisiana Dept. Conserv. Geol. Bull. 7, p. 16, pi. 1, figs. 1-5.'

Shell subovate in side view; highest about one-third 

from posterior end; dorsal margin gently arched, nearly 

straight in anterior two-thirds; ventral margin nearly 

straight; anterior margin uniformly rounded; posterior 

margin broadly rounded, subtruncate above, and with 

a short flange-like extension below. Greatest convexity 

in posterior third of shell. Right valve larger than left, 

surface smooth.

Along hinge and entire free margin, rabbeted edge 

of left valve fits inside edge of right valve. Muscle 

scar obscured by matrix. Length of figured specimen 

a left valve: 0.92 mm., height 0.55 mm.

Remarks: In possession of a straight hinge associated 

with a tendency toward a posterior "swing" (caused

8 "Cf." in this paper means either that (a) the specimen(s) are not 

well preserved, but their observable features conform to those prescribed for the species and identity, although not proven, is strongly 

suggested ; or (b), that descriptions and illustrations are insufficient for 

clear comparisons, but nevertheless concern forms to which my specimens may be referred. Both meanings are applicable to some species.

"Aff." means that the specimens probably belong to a related species, 

but available specimens are too poorly preserved or too few to warrant 

erection of a new species.

The writer believes that in a faunal study of this kind, it is more 

desirable and more useful to suggest tentative comparisons and possible 

similarities to or differences from species in other localities, by use of 

"cf." and "aff." than to imply identity by omitting "cf." or clear 

differences by introducing new specific names of doubtful validity,

9 For species designated by "cf." a bibliography of the species is given 

in the form of, but not the literal intent of, a synonymy.

by the post-ventral flange-like extension) this species 

resembles G. hannai Howe and Lea.

Occurrence: Esso Standard Oil Company Hatteras 

Light well no. 1, drill-cutting sample 1,160-1,170 feet, 

lower Miocene. U.S.N.M. 560595. Oligocene Vicksburg group and Red Bluff clay of Louisiana, Mississippi, and Alabama.

Cytherella cf. C. marlboroensis TFlrich

Cytherella marlboroensis Ulrich, 1901, Maryland Geol. Survey, 

Eocene, p. 117, pi. 16, figs. 9-13.

Occurrence: Lower Eocene, Karsten no. 1 Laughton 

well, 1,120-1,150 feet. U.S.N.M. 560724. Described 

from the Aquia formation, Upper Marlboro, Md.

Cytherella sp.

An imperfect right valve of a Oytherella (U.S.N.M. 

560725) was obtained. The outline is ovoid, posterior 

portion swollen, surface recrystallized, but apparently 

smooth.

Occurrence: Middle Eocene, North Carolina Esso 

well no. 2, 1,430-1,440 feet.

Cytherella spp. 

Text figures 3a-c

Two specimens, probably of two species of Cytherella, 

were obtained from the middle Miocene, Hatteras Light 

well no. 1, core 810-820 feet. One (text fig. 3A, 

U.S.N.M. 560726) is ovoid, smooth, with greatest convexity posterior. The other is smooth and subelliptical 

with a truncate anterodorsal margin. A specimen like 

the first example was found in the upper Miocene, Hatteras Light well no. 1, 280-290 feet.
CENOZOIC OSTKACODA 15

FIGURE 3.—Cytherellidae and Gytheridae.

a. Cytherellasp. Left side of a complete shell. Length 0.80 mm. Esso Standard Oil Co., Hatteras Light well no. 1,810-820 feet, middle Miocene, X 59. U.S.N.M. 

560726-

Page

14

6, c. Cytherella sp. Exterior and interior of a left valve. Length 0.87 mm. Esso Standard Oil Co., Hatteras Light well no. 1, 810-820 feet, middle Miocene, X 55.

U.S.N.M. 560726--.......——..._- — -—. — ._....._......—...-.—-—..--_—_.—..__.-._—.-.._.-._-_-_—- — .-—---——-—-————-—- 14

d. Xestoleberissy. Interior of a left valve. Length 0.58 mm. Esso Standard Oil Co., North Carolina Esso no. 2 well, 130-140 feet, upper Miocene, X 105. U.S.N.M.

560732-. ——__——-.__ ——————— ———__—__ ———__—__——_—_-—-———-—-_——-———-——————— ——-—— 18

e-h. Eucythere sp. Exterior and interior of left valve (X 114) and right valve (X 109) of a complete specimen. Length of left valve 0.57 mm., of right valve 0.55 mm.

Esso Standard Oil Co., Hatteras Light well no. 1, 460-470 feet, upper Miocene. U.S.N.M. 560731-.- — __——.__—————.. ——-——----- — ---------- 19

i-fc. Clithrocytheridea cf. C. broussardi (Howe and Qarrett). i, Eight side of a male; length 0.62 mm. (X 51). /. Left side of a female; length 0.75 mm. (X 56). «,

Dorsal view of a female; length 0.73 mm. (X 53). Naval Auxiliary Air Station well, 90 feet, middle Eocene. U.S.N.M. 560730. .. ———.———- —— — -—- 24 

1. Trachyleberisl cf. T. micula (Ulrich and Bassler). Exterior of a right valve. Length 0.37 mm. (X 114). Esso Standard Oil Co., Hatteras Light well no. 1, 

170-lSOfeet, upper Miocene. U.S.N.M. 560729-.—- ——..—.—— — — - — -..... — -—.—-----——-—-——-——---—--——— — —--———• 29

m, n. Acuticythereis cf. A. multipunctata Edwards. Exterior and interior of a right valve. Length 0.77 mm. (X 55). Esso Standard Oil Co., Hatteras Light well no.

1, 610-620feet, middle Miocene. U.S.N.M. 560728...——......—.—..—-—,—-—.———————-————— -———-— —-——-——- 42

o-q. Basslerites cf. B. giganticus Edwards. Dorsal, right side and ventral views of a complete shell (X 50). Length 1.22 mm. Esso Standard Oil Co. Hatteras

Light well no. 1,170-180 feet, upper Miocene. U.S.N.M. 560727———— — — ———————-_————————————————————— 47

Genus CYTHERELLOIDEA Alexander, 1929

Cytherelloidea howei Swain

Plate 1, figures 2, 3

Cytherelloidea howei Swain, 1948, Maryland Dept. Geology, 

Mines and Water Res., Bull. 2, p. 190, pi. 12, fig. 5.

Shell subquadrate in side view; dorsal margin 

slightly convex; ventral margin slightly concave 

medially; anterior margin broadly rounded, truncate.

medially. Right valve larger than left, overlap greatest 

along dorsum; greatest convexity posterior; wedgeshaped in dorsal view.

Anterodorsal, anterior, and posterior margins bear a 

broad marginal rim. A broad, ventral, longitudinal 

ridge rises about one-fourth from anterior end, and extends back to posterior end where it curves dorsaUy to 

postdorsal angle, then bends anteriorly to midlength. 

Above ventral portion of this ridge is a second, shorter
16 OSTRACODA FROM WELLS IN NORTH CAROLINA

longitudinal ridge. A, conspicuous median pit with a 

low ridge over it lies slightly above midheight. Internal features not observed.

Length of a complete shell (plate 1, fig. 2) 0.65 mm., 

height 0.38 mm., thickness 0.23 mm.; thickness of a 

second complete example (pi. 1, fig. 3) 0.27 mm.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 195 feet, lower Eocene U.S.N.M. 

560596. Described from the Aquia formation of the 

subsurface of Maryland (Swain, 1948).

Cytherelloidea sp.

An imperfect specimen representing this genus was 

collected. It bears a broad, moderately elevated marginal rim, with adjacent, inner, rather deep furrow; a 

prominent ventral longitudinal swelling, and other 

more dorsal swellings that are poorly preserved in this 

specimen.

Occurrence: Middle Eocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, 1,770-1,780 feet. U.S.N.M. 

560733.

Family CYPEIDAE Baird, 1846

Genus PAKACYPRIS Sars, 1866

Paracypris cf. P. franquesi Howe and Chambers

Plate 1, figure 6

Paracypris franquesi Howe and Chambers, 1935, Louisiana Dept. 

Conserv. Geol. Bull. 5, p. 10, pi. 2, figs. 9,13, pi. 4, figs. 15,19. 

Van den Bold, 1946, Contrib. to the study of Ostracoda, 

J. H. De Bussy, Amsterdam, p. 66, pi. 1, fig. 16. Stephenson, 1946, Jour. Paleontology, vol. 20, p. 309, pi. 42, fig. 4, 

pi. 44, fig. 11.

Paracypris strecca Schmidt, 1948, Jour. Paleontology, vol. 22, 

p. 408, pL 63, figs. 21,22.

Left valve elongate-acuminate in side view; highest 

about one-third from anterior end; dorsal margin moderately convex; ventral margin slightly concave; anterior margin uniformly rounded; posterior margin 

acuminate, extended below. Surface smooth.

Hinge of left valve formed of the slightly narrowed, 

rabbeted edge of valve, which apparently fits over right 

valve along dorsum. Other internal features obscured 

by matrix.

Length of figured specimen 1.10 mm., height 0.35 mm.

Remarks: P. franquesi Howe and Chambers was 

originally described as having a hinge groove on the left 

valve, whereas the present specimen appears to have the 

hinge of the left valve rabbeted; in shape the forms 

seem to be identical.

The type of Paracypris strecca Schmidt was examined and judged to be P. franquesi.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 2,720-2,730 feet, lower Eocene. U.S.N.M. 

560599. Occurs in the Jackson formation, upper

Eocene, of the central Gulf region (Howe and Chambers, 1935, p. 10; Bergquist, 1942, p. 105); in the Claiborne group, middle Eocene, of Texas (Stephenson, 

1946, p. 310); Aquia formation, lower Eocene of Virginia (Schmidt, 1948, p. 408) ; lower Oligocene of Cuba 

(van den Bold, 1946, p. 66).

Family BAIRDIIDJE Sars, 1887

Genus BAIRDIA McCoy, 1844

Bairdia cf. B. fortificata Brady

Plate 1, figure 14

Bairdia, fortificata Brady, 1880, Challenger Reports, vol. 1, pt. 

3, Ostracoda, p. 59, pi. 11, figs. 4a, b.

Shell subquadrate in lateral view; highest about twofifths from anterior end; hinge margin straight, about 

half of shell length, with well defined, broadly obtuse 

cardinal angles; ventral margin nearly straight in left 

valve, slightly sinuous in right; anterior margin narrowly rounded and extended medially, slightly convex 

and finely spinose below, strongly truncate above; posterior margin acuminately rounded and extended 

medially, slightly convex and finely spinose below, 

strongly truncate and slightly concave above. Left 

valve larger than right, overlapping and extending beyond the other around entire periphery; greatest overlap ventral and along dorsal slopes. Convexity of 

valves strong and nearly uniform, greatest medially. 

Surface strongly pitted, with width of interspaces 

equalling or exceeding diameter of pits.

Internal features not observed.

Length of figured specimen 0.73 mm., height 0.40 

mm., thickness 0.35 mm.

Remarks: This bairdiid specimen, unique in its 

strongly pitted surface, seems identical with Brady's 

Recent species but lack of knowledge of internal features makes the generic designation insecure. Specimens from the Tertiary of England assigned by Jones 

(1856, p. 52) to B. subdeltoidea (Muenster) are more 

finely punctate. Bairdia sp. from the Weches formation, middle Eocene of Texas (Stephenson, 1946, p. 

310, pi. 42, fig. 7) is close to B. fortificata.

Occurrence: Edenton Naval Air Base well no. 1 

Chowan County, N. C., 40 feet, upper Miocene. 

U.S.N.M. 560605. The species was originally collected 

off Booby Island at Lat. 10°36' S., Long. 141°55' E. in 

6 feet of water from a coral and sand bottom (Brady, 

1880, p. 59).

Bairdia sp.

A broken recrystallized specimen of this genus was 

obtained from the middle Eocene, Hatteras Light well 

no. 1, 2,040-2,050 feet. U.S.N.M. 560734.
CENOZOIC OSTRACODA 17

Bairdia cf. B. laevicula Edwards

Bairdia laevioula Edwards, 1944, Jour. Paleontology, vol. 18, p. 

506, pi. 85, figs. 3, 4.

Occurrence: Naval Air Base well no. 4, Edenton, N. 

C., 88 feet, middle Miocene. U.S.N.M. 560735. Described from the Duplin marl, upper Miocene at Natural Well, N. C.

Genus TRIEBELINA van den Bold, 1946

Triebelina van den Bold, 1946, Contrib. to study of Ostracoda,

J. H. De Bussy, Amsterdam, pp. 23, 73. 

Glyptobcwrdia Stephenson, 1946, Jour. Paleontology, vol. 20,

no. 4, pp. 345-347. 

Triebelina van den Bold, Stephenson, 1947, Jour. Paleontology,

vol. 21, no. 6, pp. 577-579.

Triebelina sp. 

Plate 1, figure 7

Two imperfectly preserved specimens represent this 

genus in the present collections. The surface bears three 

prominent longitudinal ridges, respectively dorsal, 

submedian, and ventral in position; ridges do not cross 

the compressed posterior end of the valve; ventral surface slopes steeply toward margin of valve, and posteriorly bears a large shallow excavation. Entire 

surface coarsely reticulate.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1,610-620 feet in the upper Miocene U. S. N. M. 

560789, and 1,380-1,390 feet in the lower Miocene. 

U. S. N. M. 560600.

Genus BAIRDOPPILATA Coryell, Sample and Jennings, 1935

Bairdoppilata? cf. B. delicatula Jennings

Plate 1, figures 8, 9

BairdoppiJ-ata delicatula Jennings, 1936, Bull. Am. Paleontology, vol. 23, no. 2, p. 45, pi. 6, fig. 7.

Shell subtriangular-ovate in side view; greatest 

height slightly postmedian; dorsal margin strongly 

arched; ventral margin gently convex; anterior margin rounded, extended medially, slightly truncate 

above; posterior margin narrowly rounded, extended 

slightly below midheight, truncate to slightly concave 

above. Left valve larger than right, greatest overlap 

dorsal and mid-ventral. Surface weakly and sparsely 

punctate.

Hinge of left valve consists of a groove for reception 

of edge of right valve. The right valve of one specimen 

was removed in an attempt to see the internal features. 

Small hinge-crenulations, characteristic of Baifdoppolita, occur near base of posterior dorsal slope; corresponding anterior features could not be seen.

Length of a figured specimen (plate 1, fig. 9) 1.25 mm., 

height 0.79 mm., thickness 0.60 mm.

Remarks: The present specimens are close to B. 

delicatula Jennings in external shell features. The internal structures are not completely known, so the 

generic assignment is tentative.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 2,135-2,145 feet, lower Eocene; U. S. N. 

M. 560602. N. C. Esso well no. 2,1,620-1,630 feet, middle Eocene. U.S.N.M. 560601. B. delicatula occurs in 

the Hornerstown formation, lower Eocene, of New 

Jersey (Jennings, 1936, p. 45).

Genus BYTHOCYPRIS Brady, 1880

Bythocypris? wicomicoensis Swain

Plate 1, figures 4, 5

BytJiocyprisf wicomicoensis Swain, 1948, Maryland Dept. 

Geology, Mines, and Water Kes., Bull. 2, p. 191, pi. 12, fig. 1.

The species was first described from the Miocene of 

the subsurface of Maryland, 200 feet below the top of 

the Calvert formation in the Ohio Oil Co.'s no. 1 Hammond well, Wicomico County. The present specimens 

closely resemble the Maryland example species. Recrystallization of the interior of the shells from both 

localities obscures the internal features so that the 

generic status remains uncertain.

Length of a figured specimen (plate 1, fig. 4) 0.93 

mm., height 0.47 mm., thickness 0.38 mm.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 1,740-1,750 feet, drill-cutting sample 

1,770-1,780 feet at top of middle Eocene. U.S.N.M. 

560597.

Bythocypris cf. B. parilis TTlrich

Bythocypris parilis Ulrich, 1901, Maryland Geol. Survey, Eocene, 

p. 117, pi. 16, figs. 5-8. Jennings, 1936, Bull. Am. Paleontology, vol. 23, no. 78, p. 45, pi. 6, fig. 8. Schmidt, 1948, Jour. 

Paleontology, vol. 22, p. 409, pi. 63, figs. 14-16.

Occurrence: Karsten no. 1 Laughton well, 1,213-1,244 

feet, in the lower Eocene U.S.N.M. 560736. Described 

from the Aquia formation, Upper Marlboro, Md., (Ulrich, 1901, p. 117, Schmidt, 1948, p. 409), and recorded 

from the Hornerstown formation of New Jersey (Jennings, 1936, p. 45).

Family CYTHERIDAE Baird, 1850

The members of this family are currently undergoing 

revision. Sylvester-Bradley (1948, p. 793) introduced 

the family Trachyleberidae to include the following 

genera discussed in this paper: Trachyleberis Brady, 

Hemicythere Sars, Pterygocythereis Blake, Buntonia 

Howe, and Favella Coryell and Fields. The present
18 OSTRACODA FROM WELLS IN NORTH. CAROLINA

writer agrees that the family Cytheridae needs revision, but doubts the validity of the Trachyleberidae as 

defined by Sylvester-Bradley (1948, p. 793) this is

Cytheracea with accommodation groove lacking or reduced to 

a narrow shelf; straight hinge, with subdivided median element; and compressed carapace (especially anteriorly and 

posteriorly) though sometimes with alae.

Many of the genera of this group of ostracodes have 

not been adequately defined and further study of them 

probably should be made before new families are proposed. In the present paper the genera listed above 

are left in the Cytheridae.

Genus XESTOLEBEBIS Sars, 1866 

Xestoleberis cf. X. longissima Schmidt

Plate 1, figure 10

Xestoleberis longissima Schmidt, 1948, Jour. Paleontology, vol. 

22, p. 411, pi. 63, figs. 11-13.

Shell elongate suboblong in lateral view; dorsal margin gently convex; ventral margin slightly concave 

medially; anterior margin narrowly rounded, extended 

below; posterior margin more broadly rounded. Left 

valve slightly larger than right, extending beyond the 

other along dorsum. Greatest convexity in posterior 

half. Surface details destroyed by recrystallization. 

Internal features also obscured by recrystallization.

Length of figured specimen 0.65 mm., height 0.25 

mm., thickness 0.26 mm.

Remarks: The present form was compared with the 

type X. longissima and on the basis of external characteristics the two are conspecific. Recrystallization of 

the surface and lack of knowledge of the internal features prevent accurate classification of the North Carolina forms. Schmidt (1948, p. 411) reported several 

similarly poorly-preserved specimens in her collections 

from the Aquia formation near Oak Grove, Md.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 2,390-2,400 feet, lower Eocene. U.S.N.M. 

560603. Described from the Aquia formation, lower 

Eocene, Maryland.

Xestoleberis? ventrostriata Swain, n. sp. 

Plate 4, figures 12, 13

Shell elongate-subovate in lateral view; greatest 

height median; dorsal margin moderately convex; ventral margin nearly straight; anterior margin narrowly 

rounded, slightly extended below; posterior margin 

more broadly rounded, extended below. Left valve 

larger than right, extending beyond the other most 

noticeably along dorsum. Ventral surface of each valve 

greatly inflated, overhanging ventral margin. Ventral portion bears weak longitudinal grooves; surface 

otherwise smooth. Internal features not observed.

Length of holotype 0.49 mm., height 0.26 mm., thickness 0.28 mm.

Relationships: This species is more elongate than X. 

dumblei Stephenson (1946, p. 320) from the Weches 

formation of Texas and X. sarsi Howe and Chambers 

(1935, p. 48) from the Jackson formation of Louisiana. 

In shape it resembles the smooth-surfaced X. incksburgensis Howe and Law (1936, p. 78) and to the 

papillate X. depressa Sars (1928, p. 244) and X. 

aurantia Baird (Sars, 1928, p. 243) of the Eecent, but 

differs from all of them in its weakly grooved ventrum.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 380-390 feet, upper Miocene. U.S.N.M. 

560659.

Xestoleberis? sp.

Text figure 3d

A left valve doubtfully assigned to this genus was 

obtained from the Upper Miocene. The shell is elongate-subovate, with the posterior margin greatly extended below midheight. The surface is minutely 

pitted, with weak longitudinal ridges along the ventral 

surface. It is much more elongate than X. ventrostriata Swain n. sp., and the ventral surface is not 

inflated.

The hinge consists of the simple edge of the valve and 

thus differs from the hingement prescribed for the 

genus. The left valve hinge of Xestoleberis according 

to Alexander (1934, p. 232) consists of an anterior 

notched groove, an interterminal denticulate bar, and 

a posterior socket. The specimen is very small and 

delicate and may be a miniature molt of Xestoleberis. 

The observed muscle scar consists of a vertical row of 

3 or 4 spots.

Occurrence: North Carolina Esso no. 2 well, 130-140 

feet, upper Miocene. U.S.N.M. 560732.

Genus ETTCYTHERE Brady 1866

Eucythere cf. E. chickasawhayensis Howe 

Plate 1, figures 11-13

Eucythere cMckasawhayensis Howe, 1936, Jour. Paleontology, 

vol. 10, no. 2, pp. 143-145, text figure 2.

Shell subtriangular in side view; greatest height 

slightly anterad of midlength; dorsal margin strongly 

convex, truncate in posterior portion; ventral margin 

nearly straight; anterior margin broadly rounded, 

slightly extended below; posterior margin narrowly 

rounded, extended ventrally, truncate above. Left 

valve slightly larger than right, greatest overlap middorsal. Greatest thickness in posterior third of shell.
CENOZOIC OSTRACODA 19

Surface more or less concentrically and coarsely 

reticulate.

Hinge of left valve consists of a prominent long 

ridge occupying the truncated postdorsal slope; near 

anterior end of ridge and joined to its ventral surface 

is a second, shorter toothlike ridge that defines a more 

dorsal, narrow, elongate socket; at posterior end of 

hinge is a narrow elongate crenulate socket; incised 

lines define the main ridge element dorsally and ventrally. Correspondingly, hinge of right valve consists of an anterior toothlike ridge and subjacent socket, 

a long narrow interterminal groove, and a posterior, 

weak, crenulate tooth. Inner lamellae are broad anteriorly but narrow abruptly to about half their width 

just anterad 10 of midventral region. The radial pore 

canals are rather widely spaced. Inner margin and line 

of concrescence are widely separated anteriorly. Muscle 

scar consists of three hourglass-shaped spots or six 

single spots in a median, curved, subvertical row, and 

an anterad U-shaped spot, open dorsally.

Length of figured specimen 0.69 mm, height 0.44 mm, 

thickness 0.43 mm.

Remarks: Howe (1936, p. 144) based his description 

of E. chickasawhayensis on two right valves, and illustrated the species by means of an outline drawing of the 

interior of one valve. The surface ornamentation of 

the present form is similar to that described but not 

illustrated by Howe. The description of the hingement 

of the present form differs in its wording from that of 

Howe, but there apparently is close similarity between 

the Gulf Coast and North Carolina examples.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 700-710 feet, upper Miocene. U.S.N.M. 

560604. Described from the lower part of the Chickasawhay formation, upper Oligocene, Wayne County, 

Miss. (Howe, 1936, p. 144).

Eucythere sp. 

Text figures 3, e-h

Outline of the single left valve found subovateacuminate, highest about one-third from anterior end; 

dorsal margin strongly arched; ventral margin nearly 

straight, slightly concave medially; anterior margin 

broadly rounded; posterior margin acuminate, strongly 

extended below. Posterior half of surface pitted. 

Greatest convexity ventral and slightly postmedian.

Hinge margin imperfect but probably consists of an 

anterior narrow rabbet-joint lying at position of great10 In this paper "posterad" and "anterad" are used as contractions 

of "posteriorad" and "anteriorad," respectively. The Latin suffix "ad" 

indicates the direction "toward"; "posterad," therefore, means "toward 

the rear," and "anterad" means "toward the front."

est height, a long ridge and a posterior narrow groove. 

Inner lamellae broadest anteriorly; line of concrescence 

and inner margin separate anteriorly. Muscle scar 

anteromedian, and consists of a curved row of 3 or 4 

spots and a more anterior large curved spot.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 460-470 feet, upper Miocene. U.S.N.M. 

560731.

Genus CYTHERIDEA Bosquet, 1852

Cytheridea? sp.

A broken and recrystallized specimen from the middle Eocene, probably is a Cytheridea or a related genus. 

The surface is coarsely pitted and the anterior margin 

is extended ventrally.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 2,180-2,190 feet. U.S.N.M. 560737.

Cytheridea? sp.

A poorly preserved incomplete left valve from the 

middle Miocene belongs to this, or to a related, genus. 

U.S.N.M. 560738.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 760-70 feet.

Genus CYTHERIDEIS Jones, 1856 

Cytheideis ashermani Ulrich and Bassler

CytJierideis ashermani Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene, p. 126, pi. 37, figs 10-16. Howe and 

others, 1935, Florida Dept. Conserv., Geol. Bull. 13, p. 14, 

pi. 3, figs. 8-10. Swain, 1948, Maryland Dept. Geology, 

Mines, and Water Res., Bull. 2, p. 195, pi. 13, fig. 1.

Cytherideis longula Ulrich and Bassler, Howe and others, idem., 

P. 14. ,

Cytherideis semicircularis Ulrich and Bassler, Howe and others, 

idem.

Occurrence: Esso Standard Oil Co., Hatteras Light 

well no. 1, 170-180 feet, upper Miocene, U.S.N.M. 

560739; from the Cape Lookout well, 101-125 feet, middle Miocene, U.S.N.M. 560740; and from the Hatteras 

Light well no. 1, 1,220-1,230 feet, lower Miocene, 

U.S.N.M. 560741. .Previously known from the middle 

Miocene.

Cytherideis longula Ulrich and Bassler

Cytherideis longula Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene, p. 128, pi. 3T, figs. 21-27. Swain, 1948, 

Maryland Dept. Geology, Mines, and Water Res., Bull. 2, 

p. 195, pi. 13, fig. 2.

Howe and others (1935) considered the form synonymous with C. ashermani Ulrich and Bassler. It may 

represent the male of that species, although it is not in 

all cases associated with the shorter and higher C.

ashermani.
20 OSTRACODA FROM WELLS IN NORTH CAROLINA

Occurrence: Middle Miocene (Calvert formation) of 

Maryland and upper Miocene at Hatteras Light well no. 

i; 170-180 feet, U.S.N.M. 560742.

Cytherideis rugipustnlosa Edwards

Gytherideis rugipustulosa Edwards, 1944, Jour. Paleontology, 

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

Occurrence: Middle Miocene, Esso Standard Oil Co., 

Hatteras Light well no. 1, 850-860 feet, U.S.N.M. 

560743; upper Miocene, North Carolina Esso well no. 2, 

350-360 feet, U.S.N.M. 560744; Pleistocene, Hatteras 

Light well no. 1, 90-100 feet, U.S.N.M. 560745. Edwards described the species from the Duplin marl of 

North Carolina.

Genus HAFLOCYTHERIDEA Stephenson, 1936

Haplocytheridea sp. aff. H. israelskyi Stephenson

Plate 1, figures 15-17

Shell subovate in side view; highest about one-third 

from anterior end; dorsal margin moderately arched, 

subtruncate behind position of greatest height; ventral 

margin nearly straight to slightly convex, somewhat 

sinuous in right valve; anterior margin broadly and 

nearly uniformly rounded, slightly spinose; posterior 

margin narrowly rounded, extended below, slightly 

truncate above. Left valve larger than right, and overlapping it except at posteroventral bend and middorsally.

Surface of each valve bears rows of large pits and intervening low ridges that are arranged concentrically 

on marginal third of surface. Two inconspicuous subvertical pitted groves occur about at midlength.

Hinge of right valve consists of an anterfor elongate 

elevated series of 6 or 7 denticles at about midheight, 

an interterminal structure that begins as a depressed 

series of tiny crenulations, gradually rises and becomes 

more coarsely crenulate and slightly broader, and a posterior elevated crenulate tooth. Some of the posterior 

crenulations are doublets. Above the back part of the 

hinge is a groove that receives a corresponding rabbeted 

overlap of the left valve. Hinge of left valve consists 

of an anterior, elongate, crenulate socket, and a crenulate structure rather strongly elevated at midlength 

but becomes progressively lower behind, and a shallow 

socket. Above midportion of hinge is a groove that 

receives the overlapping edge of right valve. Muscle 

scar consists of a subvertical row of four pits and two 

more anterior pits. Inner lamellae of moderate width, 

broadest anteriorly and sloping inward. Line of concrescence and inner margin separate. Radial canals 

numerous.

Length of figured specimen 0.77 mm., height 0.44 

mm., thickness 0.45 mm.

Remarks: In shape, hingement and coarsely pitted 

surface this form is close to H. israelskyi Stephenson 

(1944, p. 159) from the subsurface middle Tertiary of 

Jefferson County, Texas. The latter apparently lacks 

the terminal rows of pits and intervening low ridges of 

the present species. H. veatchi (Howe and Garrett) 

from the Wilcox and Claiborne groups of the Gulf 

states has stronger curving ridges and weaker pits. H. 

veatchi aquia Schmidt from the Aquia formation of the 

Middle Atlantic region is similar but lacks distinctive 

terminal ornamentation. The Aquia example seems to 

be much like the Claiborne form H. lisbonensis Stephenson which that author later (1946, p." 325) placed with 

H. veatchi. H. israelskyi to which the North Carolina 

species is most closely related is represented, in addition, in the Calvert formation, middle Miocene, of the 

subsurface of Maryland (Swain, 1948, p. 210).

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 60 feet, upper Miocene. A specimen probably of the same species, was obtained from 

the Esso Standard Oil Co. Hatteras Light well, no. 1, 

1,620-1,630 feet lower Miocene or Oligocene. U.S.N.M. 

560606.

Haplocytheridea montgomeryensis (Howe and Chambers) 

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

Cytheridea, montgomeryensis Howe and Chambers, 1985, Louisiana Dept. Conservation Geol. Bull. 5, p. 17, pi. 1, fig. 1, 

pi. 2, figs. 1-3, pi. 6, figs. 17, 18.

Cytheridea (Haplocytheridea) montgomeryensis Howe and 

Chambers, Stephenson, 1936, Jour. Paleontology, vol. 10, 

p. 700, pi. 94, figs. 3, 4, 9, text figs. Ig, h, j, k, Stephenson, 

1937, idem., vol. 16, p. 109, pi. 18, figs. 17,18.

Cytheridea montgomeryensis Howe and Chambers, Bergquist 

1942, Mississippi Geol. Survey Bull. 49, p. 106, pi. 11, fig. KL

Haplocytheridea montgomeryensis (Howe and Chambers) 

Stephenson, 1946, Jour. Paleontology, vol. 20, p. 322, pi. 42, 

fig. 29.

Shell subpyriform in side view; male dimorphs 

elongate, females shorter and higher; greatest height 

about one-third from anterior end; dorsal margin 

strongly convex, truncate behind point of greatest 

height; ventral margin nearly straight to slightly concave postmedially, the later particularly in male dimorphs; anterior margin broadly rounded, its ventral 

portion bearing several short spines; posterior margin 

acuminate,' extended below; postdorsal slope truncate, 

forming a very obtuse but distinct angle with dorsum. 

Anterior two-thirds of valves strongly convex, posterior 

third somewhat compressed. Median and anteromedian portions of shell bear eight or more subvertical, 

curved, sparsely pitted furrows, separated by inter-
CENOZOIC OSTRACODA 21

spaces that are approximately twice width of furrows; 

surface otherwise smooth.

Left valve larger than right, extending beyond the 

other most along dorsum and ventrum. Internal features not well preserved in specimens at hand.

Length of figured female shell (plate 2, fig. 1) 0.85 

mm., height 0.46 mm., thickness 0.35 mm.

Remarks: The internal features of the present specimens are not known but the form probably is conspecific 

with Haplocytheridea montgomeryensis. The flattened 

posterior and dorsal slopes, the ventrally acuminate 

posterior end, and the surface ornamentation are characteristic of the species.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 1,740-1,750 feet (male dimorphs only) 

middle Eocene; Esso no. 2 well 1,610-1,620 feet, middle 

Eocene; Naval Auxiliary Air Station well, Washington, N. C., 115 feet, middle Eocene; N. C. Esso no. 2 

well 1,950-1,960 feet, lower Eocene. In the Gulf region, 

the species occurs in the Claiborne group and the Jackson formation. U.S.N.M. 560607, 560612, 560613.

Haplocytheridea cf. H. veatchi (Howe and Garrett) 

Plate 1, figure 22

Cytheridea miilleri (Minister) (part), Cushman, 1925, Am.

Assoc. Petroleum Geologists Bull., vol. 9, p. 301, pi. 8,

figs. 4a-c. 

Cytheridea veatchi Howe and Garrett, 1934, Louisiana Dept.

Conserv. Geol. Bull. 4, p. 43, pi. 3, figs. 1-4. 

Cytheridea (Haplocytheridea) veatchi Howe and Garrett,

Stephenson, 1938, Jour. Paleontology, vol. 12, p. 574, pi. 67,

fig. 6, text figs. 25-27.

Cytheridea (Phractocytheridea) compressa Sutton and Williams, 1939, idem., vol. 13, p. 572, pi. 64, figs. 23-25. 

Cytheridea (Haplocytheridea) lisbonensis Stephenson, 1942,

idem., vol. 16, p. 108, pi. 18, figs. 11,12. 

Haplocytheridea lisbonensis Stephenson, 1944, idem., vol. 18,

p. 449, pi. 76, fig. 12. 

Haplocytheridea veatchi (Howe and Garrett) Stephenson, 1946,

idem., vol. 20, p. 325, pi. 42, fig. 27, pi. 44, fig. 14. 

Haplocytheridea veatchi aquia Schmidt, 1948, idem., vol. 22,

p. 424, pi. 63, figs. 1-7.

Valves subovate in side view; greatest height about 

one-third from anterior end; dorsal margin moderately 

arched, nearly straight in posterior two-thirds; ventral 

margin nearly straight, converging backward toward 

dorsum; anterior margin broadly and uniformly 

rounded, bearing 10 or more spines along its ventral 

part; posterior margin narrowly rounded, extended 

below. Left valve larger than right; complete shells 

not observed, but greater height of left as compared to 

right valves suggests that greatest overlap is not terminal. Entire surface of each valve bears subvertical, 

weak, rather closely spaced, narrow, pitted grooves that 

are convex forward in front of midshell and backward

behind midshell. Posteroventrally, surface bears several small pustules.

Hingement consists in right valve of terminal, narrow, elongate, taxodont teeth and intervening, less 

elevated, finely crenulate bar, bounded dorsally by a 

narrow groove. Hinge of left valve not clearly observed. Muscle scar consists of a vertical row of four 

spots, and two, more anterior spots. Inner lamellae 

broadest anteriorly; line of concrescence and inner margin separated terminally. Kadial canals not clearly 

observed.

Length of figured specimen 0.75 mm., height 0.44 mm., 

thickness 0.27 mm.

Remarks: The present form is close to H. veatcM 

(Howe and Garrett) in shape, hingement, and in the 

possession of numerous subvertical grooves on the surfaces of the valves. The intervening ridges are lower 

on the specimens at hand than on typical members of the 

species but Stephenson (1946, p. 325) reports that the 

strength of the ridges is varied. The type of H. veatchi 

aquia Schmidt from the Aquia formation of Maryland 

and Virginia was examined and although more weakly 

ornamented terminally than typical examples of H. 

veatchi is so similar that its separation as a distinct 

variety is of questionable value.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 1,740-1,750 feet, middle Eocene; 

U.E.N.M. 560611. Occurs in Wilcox and Claiborne 

groups of the Gulf region (Stephenson, 1946, p. 325), 

Aquia formation of the Middle Atlantic region 

(Schmidt, 1948, p. 425).

Haplocytheridea cf. H. Wallace! (Howe and Garrett) 

Plate 2, figures 6, 7

Cytheridea miilleri (Miinster) (part), Stadnichenko, 1927, Jour. 

Paleontology, vol. 1, p. 237, pi. 39, figs. 14-17, not fig. 13.

Cytheridea wallacei Howe and Garrett, 1934, Louisiana Dept. 

Conserv. Geol. Bull. 4, p. 44, pi. 3, figs. 5-8.

Cytheridea (Haplocytheridea) wallacei Howe and Garrett, 

Stephenson, 1938, Jour. Paleontology, vol. 12, p. 575, pi. 67, 

fig. 25, text figs. 17, 18.

Cytheridea, (Haplocytheridea) habropapillosa Sutton and Williams, 1939, idem., vol. 13, p. 570, pi. 64, figs. 20-22. Stephenson, 1942, idem., vol. 16, p. 107, pi. 18, figs. 21, 22.

Halplocytheridea habropapillosa (Sutton and Williams), Stephenson, 1944, idem., vol. 18, p. 449, pi. 76, fig. 4.

Haplocytheridea wallacei (Howe and Garrett), Stephenson, 

1946, idem., vol 20, p. 325, pi. 42, fig. 28.

The present specimens exhibit the following characteristics :

Shell subpyriform in side view; greatest height onethird shell length from anterior end; dorsal margin 

moderately to strongly arched, slightly truncate on posterior slope; ventral margin sinuous, convex in front,
22 OSTRACODA FROM WELLS IN NORTH CAROLINA

concave behind; anterior margin broadly and nearly 

uniformly rounded, slightly extended below and be^ring six short spines along lower portion in each valve; 

posterior margin acuminate, strongly extended below. 

Left valve larger than right, overlapping and extending 

beyond the other around entire periphery. Anterior 

two-thirds of shell strongly convex; midventrally the 

swollen shell overhangs ventral margin. Posterior end 

compressed, especially in ventral region. Shell subtriangular in end view.

Anteroventral two-thirds of each valve ornamented 

with large, low pustules that in part coalesce to form 

irregular ridges, and with large intervening pits. Anteriorly, pustules are in curved rows about parallel to 

anterior margin. Posterodorsal third of surface 

smooth.

Hinge of left valve consists of terminal, crenulate 

groove; hinge of right valve not seen. Other internal 

features not observable in these specimens.

Length of a relatively short high specimen (pi. 2, 

fig. 7), probably a female dimorph, 0.57 mm., height 

0.32 mm., thickness 0.33 mm. Length of a probable 

male dimorph (pi. 2, fig. 6) 0.61 mm., height 0.40 mm.

Remarks: The present specimens possibly are a distinct variety of H. wallacei as shells of that species do 

not bear pits between the surface pustules.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 1,740-1,750 feet, middle Eocene U.S.N.M. 

560615; North Carolina Esso well no. 2, 1,950-1,960 

feet, lower Eocene. U.S.N.M. 560616. According to 

Stephenson (1946, p. 326), E. wallacei occurs in the Wilcox and Claiborne groups of the Gulf States.

Haplocytheridea? cf. H.? subovata (TTlrich and Bassler) 

Plate 1, figures 19, 20

Cytheridea subovata, Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene volume, p. 124, pi. 37, figures 1-8.

Shell subovate-elongate in lateral view; greatest 

height slightly post-median; dorsal margin gently 

arched, its sloping posterior portion nearly straight; 

ventral margin gently convex in left valve; nearly 

straight in right valve; anterior margin broadly 

rounded, bearing 4 or 5 short spines in its ventral part; 

posterior margin narrowly rounded, extended below, 

truncate above, that of right valve bearing 5 short spines 

in its ventral part. Left valve larger than right, greatest extension in midventral portion.

Posterior surface of right valve bears two or three 

curved subvertical grooves; corresponding features on 

left valve are inconspicuous. Entire surface of each 

valve bears widely spaced shallow pits. Hingement 

and other internal features not observed.

Remarks: The present material probably is conspecific 

with Cyiheridea subovata Ulrich and Bassler from the 

Calvert formation, middle Miocene of Maryland. Its 

external shell characteristics resemble those of Haplocytheridea, but critical internal characters are 

unknown.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 1,620-1,630 feet, U.S.N.M. 560608 and 

560609. Lower Miocene or Oligocene; Bogue water 

well no. 65, Carteret County, 150 feet, upper Miocene(«); U.S.N.M. 560759.

Haplocytheridea sp. aff. H. hammondensis (Swain) 

Plate 1, figure 21

Shell subovate in side view; highest slightly anterad 

of midlength; dorsal margin gently arched, ventral 

margin nearly straight in right valve, slightly convex 

in left; terminal margins nearly equal in curvature, 

bearing ventral, short, flangelike extensions. Left 

valve larger than right and extending beyond it, except 

ventro-terminally. In edge view, posterior third of 

shell rather strongly swollen, possibly a female dimorphic feature; behind swollen area, surface slopes 

gradually to margins. Surface bears widely spaced 

pits of various sizes, without systematic arrangement.

Hinge of right valve consists of terminal, slightly 

elevated notched dental areas, with intervening finely 

crenulate bar formed of the narrowed valve edge. 

Hinge of left valve consists of terminal, shallow, 

notched sockets, connected by a narrow, crenulate 

groove. Muscle scar lies forward of shell beneath 

anterior end of hinge; it consists of a vertical row of 

four spots, and two or more anterior spots. Inner 

lamellae of moderate width anteriorly and vertically, 

becoming narrower posteriorly; line of concrescence and 

inner margin separated terminally. Radial pore canals 

were not clearly observed but probably are widely 

spaced.

Length of a complete shell (pi. 1, fig. 22) 0.58 mm., 

height 0.33 mm., thickness 0.27 mm.

Remarks: The present form resembles H. hammondensis Swain (Swain 1948, p. 210, pi. 14, fig. 15), 

and H. texana Stephenson (1944, p. 160). In internal 

features and general shape, particularly the relatively 

narrow anterior end, it is close to H. hammondensis 

from the Calvert formation, middle Miocene, of the 

subsurface of Maryland, but the Maryland example 

has a more weakly pitted surface and is less tumid. 

H. texana, from the middle Tertiary Marffinulina 

idiomorpJia zone of the subsurface of Texas, is highest 

at midlength, more pointed posteriorly and more 

weakly pitted than the North Carolina form.
CENOZOIC OSTRACODA 23

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., at a depth of 90 feet, middle Eocene; 

U.S.N.M. 560610.

Haplocytheridea? cf. H. goochi (Stephenson) 

Plate 2, figure 8

Cytheridea (Haplocytheridea) goochi Stephenson, 1942, Jour. 

Paleontology, vol. 16, p. 106, pi. 18, figs. 9,10.

Shell elongate-subquadrate in side view; highest 

about one-third from anterior end; hinge margin 

straight, about half of shell length, defined by broadly 

obtuse cardinal angles; ventral margin nearly straight, 

slightly concave medially in right valve; anterior margin truncate above, rounded and extended below; posterior margin narrower, truncate above, rounded and 

extended below. Left valve slightly larger than right, 

extending beyond it postdorsally and midventrally. 

Valves moderately convex; greatest convexity in posterior third. Surface bears large, scattered, rounded 

pits.

Internal features not observed in the single specimen 

at hand.

Length 0.61 mm., height 0.31 mm., thickness 0.28 mm.

Remarks: In shape and surface ornamentation this 

form is close to H. goochi (Stephenson) but the internal 

features on which positive generic placement can be 

made, were not seen.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, core 2,196-2,206 feet, middle Eocene 

U.S.N.M. 560617. Described from the Claiborne group 

of Alabama (Stephenson, 1942, p. 106).

Haplocytheridea cf. H. nowotnyi Stephenson

Haplocytheridea nmcotnyi Stephenson, 1946, Jour. Paleontology, 

vol. 20, p. 324, pi. 42, fig. 26.

Several specimens that seem to represent this species 

were obtained. The shell is subovate, strongly inflated 

and bears weak pits scattered over the surface.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 90 feet U.S.N.M. 560746, and from the 

Esso Standard Oil Co., Hatteras Light well no. 1, 

2,140-2,150 feet, middle Eocene, U.S.N.M. 560758.

Haplocytheridea? cf. H? hopkinsi (Howe and Garrett) 

Plate 2, figure 5

Cytheridea hopkinsi Howe and Garrett, 1934, Louisiana Dept.

Conserv., Geol. Bull. 4, p. 31, pi. 1, figs. 16-18. 

ICytheridea (Leptocytheridea) hopMnsi Howe and Garrett,

Stephenson, 1938, Jour. Paleontology, vol 12, p. 583, pi. 67,

figs. 13,14, text figs. 8,11,12. 

ICytheridea (Haplocytherideat) sp., Stephenson, 1942, idem.,

vol. 16, p. 110, pi. 18, figs. 7, 8.

Left valve subovate in side view; highest about onefourth from anterior end; hinge margin nearly straight 

behind position of greatest height, and equal to about 

half of shell length; ventral margin nearly straight to 

slightly concave postmedially, converging strongly 

backward with respect to dorsum; anterior margin 

broadly and nearly uniformly rounded; posterior margin acuminately curved at its ventral bend, truncate 

above. Surface finely pitted; anteromedially there is 

a cluster of larger, more conspicuous pits, some of which 

are arranged in short subvertical rows. Internal features not observed.

Length of figured left valve 0.63 mm., height 0.42 mm.

Remarks: The shape of the shell and the hinge characters as described by Howe and Garrett (1934, p. 31, 

Stephenson, 1938, p. 583) from the Nanafalia formation, 

suggest that this species belongs in Haplocytheridea 

Stephenson. The form referred by Stephenson (1938, 

p. 583) to Cytheridea (Leptocytheridea) hopkinsi Howe 

and Garrett, from the Nanaf alia and Tuscahoma formations has a hinge resembling that of Clithrocytheridea, 

but in other shell features it is similar to Haplocytheridea. Stephenson later (1941, pp. 426, 427) abandoned 

Leptocytheridea and considered species he had assigned 

to that subgenus to be immature molts of other cytherideid ostracodes. Subsequently Stephenson (1942, p. 

110) reported as Cytheridea (Haplocytheridea?) sp., 

specimens from the Claiborne group of Texas that "are 

closely similar to the form described by Howe and Garrett ... as Cytheridea hopkinsi."

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 2,840-2,850 feet, lower Eocene U.S.N.M. 

560614; Nanaf alia formation, lower Eocene of Louisiana; Nanaf alia and Tuscahoma formations, Wilcox 

group of Alabama; Claiborne of Texas.

Genus CLITHROCYTHERIDEA Stephenson, 1936

Clithrocytheridea cf. C. smithvillensis Stephenson

Plate 2, figure 9

Clithrocytheridea smithvillensis Stephenson, 1946, Jour. Paleontology, vol. 20, p. 327.

Shell subovate in side view; greatest height about 

two-fifths from anterior end; dorsal margin moderately convex; ventral margin nearly straight to 

slightly concave medially; anterior margin rounded, 

extended below, truncate above in right valve; ventral 

portion of anterior margin in each valve bears a low 

but distinct slightly spinose flange; posterior margin 

narrowly rounded, rather strongly extended below, 

truncate above in right valve; ventral portion of posterior margin bears a low flange. Left valve larger than
24 OSTRACODA FROM WELLS IN NORTH CAROLINA

right, greatest projection along dorsal slopes. Surface 

bears large scattered pits and numerous, very small, 

closely spaced, weak pits. Hingement and other internal features not observed.

Length of figured specimen 0.52 mm., height 0.27 

mm., thickness 0.23 mm.

Remarks: In outline and pitted surface ornamentation this form is like Haplocytheridea hadleyi (Stephenson) from the basal part of the Moody's Branch 

marl and underlying transition beds in Mississippi. 

As described, however, that species lacks the ventral 

terminal flanges. Clithrocytheridea rugata Schmidt 

(1948, p. 428) from the Aquia formation of Virginia 

has a more sinuous ventral margin and lesser convexity, 

but otherwise is closely similar to C. smithvillensis. 

Topotypes of C. smithvillensis resemble the specimens 

from North Carolina, but the internal characteristics 

of the latter are not known and the present designation 

is tentative.

Occurrence: Esso Standard Oil Co., North Carolina 

Esso no. 2,1,480-1^490 feet, middle Eocene U. S. N. M. 

560618. Described from the Weches formation, Claiborne group at Smithville, Tex. (Stephenson, 1946, p. 

327).

Clithrocytheridea virginica Schmidt

Plate 2, figures 10-13

Clithrocytheridea virginica Schmidt, 1948, Jour. Paleontology, 

vol. 22, p. 429, pi. 64, figs. 21-23.

The external features of the species have been adequately described by Schmidt.

Hinge of right valve consists of an anterior, moderately elevated, elongate, crenulate dental area; a posterior, shorter, less elevated, crenulate dental area; and 

an intervening long, finely crenulate rabbet-joint shelf 

that is bounded dorsally by a strong ridgelike extension 

of the valve margin, but ventrally lacks a confining 

ridge. Hinge of left valve consists of terminal elongate, crenulate sockets, and an intervening thick, 

crenulate bar, formed of the valve edge. Muscle scar 

lies beneath anterior end of hinge, and consists of a 

vertical row of four spots and two more anterior spots. 

Inner lamellae broad and parallel to free margins; 

inner margin and line of concrescence nearly coincide. 

Marginal pore canals numerous, closely but irregularly 

spaced, and present around entire free margin.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C. 115-120 feet, middle Eocene U. S. N. M. 

560619. Described from the Aquia formation of Maryland (Schmidt, 1948, p, 429).

Clithrocytheridea cf. C. caldwellensis (Howe and Chambers) 

Plate 2, figure 28

Cytheridea f caldwellensis Howe and Chambers 1935, Louisiana

Dept. Conserv. Geol. Bull., p. 11, pi. 1, fig. 7, pi. 2, figs. 4-6. 

Cytheridea (Clithrocytheridea) caldwellensis Howe and Chambers, Stephenson, 1937, Jour. Paleontology, vol. 11, p. 154,

pi. 26, fig. 13. 

Clithrocytheridea caldwellensis (Howe and Chambers) Stephenson, 1946, Jour. Paleontology, vol. 20, p. 327, pi. 42, fig. 13.

Shell subquadrate in side view ; greatest height about 

one-third from anterior end; hinge margin straight, 

about half of shell length; ventral margin nearly 

straight; anterior margin broadly roundedj slightly 

extended below ; posterior margin acuminate, extended 

below, truncate above.

Surface ornamentation consists of a marginal anterior 

broad, low, swelling; a posterior and postventral low 

inconspicuous ridge separated from shell margin by a 

compressed zone ; a posterior broad, longitudinal swelling bounded on all sides except the dorsal by a shallow, 

broad furrow ; most of surface coarsely pitted.

Internal features not observed because of poor 

preservation.

Length of a left valve (plate 2, fig. 28) 0.55 mm., 

height 0.31 mm.

Remarks: The specimen so closely resembles C. caldwellensis externally that probably the two are conspecific. Eecrystallization and matrix obscure the inner 

structures so that the identification is tentative.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no 1, core 2,135-3,145 feet, middle Eocene 

U.S.N.M. 560631 ; Claiborne and Jackson groups of the 

Gulf states (Stephenson, 1946, p. 327).

Clithrocytheridea cf C. broussardi (Howe and Garrett) 

Text figures 3i-fc

broussardi Howe and Garrett, 1934, Louisiana Dept. 

Conserv., Geol. Bull. 4, p. 30, pi. 1, figs. 12-15. 

Cytheridea (Clithrocytheridea) broussardi, Howe and Garrett, 

Stephenson, 1938, Jour. Paleontology, vol. 12, p. 576, pi. 67, 

fig. 24, text figs. 12-15.

Occurrence: Several examples were found in the 

middle Eocene samples from the Naval Auxiliary Air 

Station well, Washington, N. C., 90 feet; U.S.N.M 

560730 previously reported from the Wilcox group 

(lower Eocene).

Clithrocytheridea sp. 

Plate 2, figure 14

Shell subovate in side view ; highest about one-third 

from anterior end ; dorsal margin gently convex, nearly 

straight behind position of greatest height; ventral
CENOZOIC OSTKACODA 25

margin nearly straight to slightly concave medially; 

anterior margin rounded, extended below, subtruncate 

above. Valves nearly equal in size, the left slightly 

larger. Valves moderately convex, greatest convexity 

post median; posterior end somewhat compressed. 

Surface ornamented by strong scattered pits, corresponding to positions of normal canals; a conspicuous 

longitudinal broad furrow lying behind and slightly 

below middle of shell; an obscure dorsal longitudinal 

swelling and four weak subvertical furrows in dorsal 

third of valve. The anterior furrow trends obliquely 

forward and is suggestive of the anteromedian sulcus 

present in some Jurassic and Cretaceous cytherideids.

Hinge of right valve consists of terminal elongate, 

finely crenulate teeth and an interterminal, narrow, 

finely crenulate groove. Hinge of left valve correspondingly consists of terminal crenulate sockets and an 

interterminal high crenulate bar. Inner lamellae of 

moderate width, sloping steeply toward valve interior. 

Line of concrescence and radial canals not observed.

Length of a right valve 0.56 mm., height 0.30 mm.

Remarks: In general shape and surface ornamentation this form closely resembles Haplocytheridea harrisi 

(Stephenson) from the Nanafalia and Tuscahoma formations of the Wilcox group of Alabama. However, 

its hingement is that of Clithrocytheridea and not of 

Haplocytheridea. Three species of Clithrocytheridea 

in the Wilcox of Alabama are similar to the present 

form in outline and in coarsely ornamented surface: 

C. nanafaliensis (Stephenson), C. alexanderi (Stephenson), and C. broussardi (Howe and Garrett). G. 

nanafaliensis seems closest to the present species but, 

as illustrated it lacks the conspicuous posteromedian 

furrow. Clithrocytheridea virginica Schmidt from the 

Aquia formation of Maryland and Virginia possesses 

a submedian furrow but has a more acuminate posterior 

margin, and bears marginal swellings and enclosed 

furrows that are lacking in the present example.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, Dare County, N. C., core 2,593-2,603 feet, 

lower Eocene U.S.N.M. 560620.

Genus LOXOCONCHA Sars, 1865

Loxoconcha subrhomboidea Edwards

Plate 2, figures 18,19

Loxoconcha sulyrhomboi&ea, Edwards, 1944, Jour. Paleontology, 

vol. 18, p. 527, pi. 88, figs. 28-32.

Shell subrhomboidal in side view; highest about twofifths from posterior end; hinge margin slightly convex, 

length about half of shell; ventral margin somewhat 

sinuous, slightly concave about one-third from anterior 

end; anterior margin rounded, extended below, slightly

truncate ventrad of cardinal angle; posterior margin 

more broadly rounded, subacuminate to slightly caudate 

just above midheight. Valves of about equal size, 

greatest convexity median to somewhat postmedian. 

Free margins bear a narrow but distinct rim, broadest 

anteriorly. Marginal half of each valve bears 4 or 5 

narrow concentric ridges. Surface closely but weakly 

pitted.

Hinge of right valve consists of the following elements: an anterior small socket; a postjacent and 

slightly more ventrad, small, elongate tooth dorsad of 

which is a small, inconspicuous socket; an interterminal 

narrow, very weakly crenulate groove; and a posterior 

curved tooth, concave ventrally, with a median saddle 

and with several weak markings on its surface. Hinge 

of left valve consists of an anterior curved tooth, concave ventrally, very low and weak posteriorly; an interterminal narrow, very weakly crenulate bar formed of 

narrow edge of valve; and a posterior hinge process consisting of the following elements, progressing posteriorly : a small socket, a small beaklike tooth, a larger 

socket, and a tiny, inconspicuous tooth. Ventral margin 

of right valve grooved for reception of an interlocking 

ridge in marginal portion of left valve.

Inner lamellae rather broad, with the greatest width 

.anterior; posteriorly, lamellae formed as a rather broad 

platform, bounded on its inner side by a high knifeedged ridge; line of concrescence and inner margin 

widely separated terminally; ventrally they nearly 

coincide. Marginal pore canals few, simple, and widely 

spaced. Muscle scar consists of a slightly anteromedian 

curved row of four spots, concave anteriorly, and one 

large spot just in front of dorsal part of main group, 

a single spot located some distance in front of the main 

group, and two small spots anteroventrad of the main 

group.

Length of a figured specimen (pi. 2, fig. 18) 0.53 mm., 

height 0.31 mm., thickness 0.27 mm.

Remarks: The specimens from North Carolina wells 

were compared with the type of L. subrhomboidea Edwards. The weak concentric ridges are obscure except 

when the specimen is coated with ammonium chloride. 

The platform-like posterior portion of the inner 

lamellae is absent in some specimens and may be a 

dimorphic feature.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 75 feet, U.S.N.M. 560623 Esso Standard 

Oil Co.; Hatteras Light well no. 1, 320-330 feet, upper 

Miocene U.S.N.M. 560770; Edenton Naval Air Base 

well no. 4, Chowan County, 88 feet, middle Miocene 

U.S.N.M. 560768; Hatteras Light weU no. 1,1,090-1,100 

feet, lower Miocene U.S.N.M. 560769. Described from
26 OSTEACODA FROM WELLS IN NORTH CAROLINA

the Duplin marl, upper Miocene of North Carolina (Edwards, 1944, p. 527); present in Yorktown formation 

(upper Miocene) of Virginia.

Loxoconcha cf. L. reticularis Edwards

Loxoconcha reticularis Edwards, 1944, Jour. Paleontology, vol.

18, p. 527, pi. 88, figs. 26, 27.

Occurrence: Two examples from the upper Miocene, 

Esso Standard Oil Co., Hatteras Light well no. 1, 

460-470 feet, U.S.N.M. 560747; described from exposures of Duplin marl in North Carolina.

Loxoconcha edentonensis Swain, n. sp. 

Plate 2, figures 20, 21

Shell subovoid in side view; greatest height about 

median; dorsal margin gently convex; ventral margin 

nearly straight, passing with smooth curvature into posterior margin; anterior margin rounded, slightly 

truncate at dorsal bend; posterior margin broadly 

rounded, with median portion rather strongly curved. 

Valves approximately equal in size; greatest convexity 

in posterior portion of shell; posterior end compressed.

Entire margin of each valve bears a narrow, well 

defined, elevated rim. Mid-dorsally, exposed marginal 

rims flare apart to form a lenticular depression as seen 

in dorsal view. Entire surface ornamented by strong 

ridges that are concentrically arranged except in median portion, where they are short, discontinuous, and 

branching, but more or less longitudinal.

Hinge of right valve consists of an anterior small 

socket with postjacent and slightly more ventral 

rounded tooth, dorsad of which is a deep, short furrow; 

an interterminal narrow groove; and a posterior elongate, curved toothlike ridge, concave ventrally. Hinge 

of left valve consists of an anterior elongate, somewhat 

irregular toothlike ridge; an interterminal narrow bar 

formed of narrowed edge of valve, and a posterior, 

elongate, curved socket, below whose center is a small 

rounded tooth.

Muscle scar consists of an anteromedian curved row 

of four spots, a fifth spot lying just in front of dorsal 

part of main group, and a large spot considerably in 

front of main group. Inner lamellae fairly broad, line 

of concrescence and inner margin widely separated; 

posteriorly, inner lamellae form a small platform 

which, near its inner margin, is traversed by a distinct 

narrow ridge. Radial canals not clearly observed but 

seem to be few and widely spaced.

Length of holotype, a complete example, 0.65 mm., 

height 0.39 mm., thickness 0.32 mm.

Relationships: The ovoid shape and pattern of surface ridges apparently distinguish this species from

other described members of Loxoconcha. The transverse ridges on the posterior portion of the inner lamellae resemble those of L. subrhomboidea Edwards, which 

is probably a related species.

Occurrence: Edenton Naval Air Base well no. 1, 

Chowan County, N. C., 40 feet, upper Miocene; 

U.S.N.M. 560626 and 560627.

Loxoconcha cf. L. mcbeanensis Murray 

Plate 2, figures 22, 23

Loxoconcha mcbeanensis Murray, 1938, Jour. Paleontology, vol. 

12, p. 591, pi. 68, figs. 7, 10.

The specimens from North Carolina apparently are 

examples of this species. Except for its greater length, 

this form is very similar to Loxoconcha sp. aff. 

L. claibomensis and may indicate sexual dimorphism. However, the two forms were obtained from 

different stratigraphic levels.

Length of a figured specimen (pi. 2, fig. 22) 0.44 mm., 

height 0.22 mm., thickness 0.18 mm.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 130 feet, middle Eocene U.S.N.M. 

560628. Described from the McBean formation, middle 

Eocene, of Georgia.

Loxoconcha sp. aff. L. claibornensis Murray 

Plate 2, figures 16, 17

Shell subquadrate in side view; greatest height 

median; hinge margin straight, about five-eighths of 

shell length, with well-defined cardinal angles of which 

the anterior is the more obtuse; ventral margin nearly 

straight, passing with uniform broad curvature into 

posterior margin and bending more sharply into anterior margin; anterior margin broadly rounded, 

extended below, slightly truncate above; posterior margin broadly rounded, subacuminate a little dorsad of 

midheight, truncate above. Left valve slightly larger 

than right valve. Greatest convexity slightly postmedian.

Terminal areas strongly compressed. Margin of each 

valve bears a narrow distinct rim, continuous except at 

the postcardinal angle where there is an en echelon 

effect; a narrow groovelike depression forms inner boundary of rim along free margins. Remainder of shell 

ornamented by rather strong ridges and intervening 

pitted grooves; except anteriorly, outer series of ridges 

arranged more or less concentrically, exhibiting greatest 

strength in ventral region; more median series of ridges 

arranged longitudinally.

Internal features not observed owing to poor 

preservation.
CENOZOIC OSTRACODA 27

Length of a complete example (plate 2, fig. 16) 0.42 

mm., height 0.26 mm., thickness 0.21 mm.

Remarks: In describing L. claibornensis Murray 

(1938, p. 588) emphasized the concentrically arranged 

pits about the outer portion, arid a reticulate pattern of 

pits on the midportion. He did not specifically refer to 

ridges separating the rows of pits, such as characterize 

the present examples, nor did he refer to marginal rims. 

Stephenson (1946, p. 315) described the surface ornamentation as consisting of small pits aligned between 

low, rounded ridges. He stated that the species exhibits 

considerable variation but did not refer to distinct 

marginal rims. Loxoconcha corrugata Alexander, from 

the Wills Point formation, Midway group, of Texas, is 

closely similar but the midventral portion of the valves 

is perhaps more strongly inflated. A new species is not 

erected on the basis of the North Carolina specimens 

because the internal characters are unknown. Additional specimens may reveal this form to be a connecting 

link between L. corrugata and L. claibornensis.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 115-120 feet, middle Eocene U.S.N.M. 

560622.

Loxoconcha cf. L. creolensis Howe and Chambers 

Plate 2, figure 15

Loxoconcha creolensis Howe and Chambers, 1935, Louisiana 

Dept. Conserv. Geol. Bull. 5, p. 40, pi. v, fig. 13. Swain, 1948, 

Maryland Dept. Geology, Mines, and Water Res. Bull. 2, 

p. 194, pi. 12, fig. 13.

Shell subquadrate in side view; greatest height median ; hinge margin nearly straight, about two-thirds of 

shell length, bounded by broadly obtuse cardinal angles; 

ventral margin moderately convex, converging posteriorly with respect to dorsum; anterior margin broadly 

rounded, slightly extended below; posterior margin 

more narrowly rounded, extended and very slightly 

caudate above. Left valve slightly larger than right. 

Greatest convexity median.

Terminal margins provided with low, unornamented 

rims; antero-midventrally are two short ridges, adjacent and subparallel to valve margins. Prominent 

curving ridges, forming slight alate expansions, occupy 

median and posterior portions of ventral surfaces; in 

ventral view midventral portion of ridges overhangs 

valve margins. Median two-thirds of valves ornamented with conspicuous large pits that are in part arranged in longitudinal rows. A small eye tubercle lies 

just beneath anterior cardinal angle. Internal features 

not observed.

Length of figured specimen 0.35 mm., height 0.23 mm., 

thickness 0.19 mm.

Remarks: The present form is similar to L. creolensis 

Howe and Chambers in general shape and surface ornamentation; particularly the ventral alaeform ridges 

that slightly overhang midventral portion of shell, and 

the horizontal rows of pits. Positive identification is 

impossible because the internal features are not exposed 

in the present example.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 90 feet, middle Eocene, U.S.N.M. 

560621. Described from the Jackson formation, upper 

Eocene of Louisiana (Howe and Chambers, 1935, p. 40), 

and also occurs in the subsurface Eocene of Maryland 

(Swain, 1948, p. 194).

Loxoconcha cf. L. surreala Murray 

Plate 2, figure 24

Loxoconcha surreala Murray, 1938, Jour. Paleontology, vol. 12, 

p. 590, pi. 68, figs. 5, 8.

Shell subovate in lateral view; greatest height median ; hinge margin slightly convex, about two-thirds of 

shell length; ventral margin gently convex, posteriorly 

converging with dorsum; anterior margin broadly 

rounded, slightly extended at ventral bend, truncate 

near dorsal bend; posterior margin narrowly rounded, 

extended and somewhat caudate a little above midheight, slightly concave above. Valves about equal, 

convexity moderate, greatest medially.

Ends rather strongly compressed; free margins bear 

narrow, low, but distinct rims; antero-midventrally, 

rims are absent at position of cythereid inturning of 

valve edges; narrow grooves bound marginal rims on 

their inner sides. Inner portion of surface of each valve 

ornamented as follows: a strong ridge subparallel and 

close to dorsal margin which gradually diverges from 

margin posteriorly and mid-dorsally extends rather 

strongly beyond margin of valve; a less distinct ridge 

that extends ventral! y from anterior end of dorsal 

ridge to a point below midheight; posterior end of dorsal ridge bifurcates into a short spur directed toward 

posterior cardinal angle and a long curving ridge that 

runs subparallel to posterior and ventral margins as far 

forward as anteroventral and marginal bend; midventrally, this ridge is strongly elevated and forms a short 

ala; just above midheight is a narrow, moderately elevated, somewhat angularly sinuous, longitudinal ridge; 

below it is a shorter, curved, longitudinal ridge; short 

spurs are directed inward from submarginal ridges at 

several places, and similar spurs project from flanks 

of median longitudinal ridge.

Internal features not observable in single whole specimen at hand.
28 OSTRACODA FROM WELLS IN NORTH CAROLINA

Length of figured specimen 0.38 mm., height 0.23 

mm., thickness 0.20 mm.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 135 feet, middle Eocene; U.S.N.M. 560629. 

Described from the Cook Mountain formation, Claiborne group, of Winn Parish, La. (Murray, 1938, p. 

590).

Genus TRACHYLEBERIS, Brady, 1898

Trachyleberis evax (Ulrich and Bassler)

Plate 3, figures 1-3

Cythere evax Ulrich and Bassler, 1904, Geol. Survey, Miocene 

vol., p. 119, pi. 36, figs. 6-8.

Gythere evax ollongula, Ulricll and Bassler, idem., figs. 9, 10.

Gythereis evax (Ulrich and Bassler), van den Bold, 1946, Contrib. to the Study of Ostracoda, Amsterdam, p. 90, pi. 21, 

fig. 19. Swain, 1948, Maryland Dept. Geology, Mines, and 

Water Res., Bull. 2, p. 204, pi. 12, figs. 19, 20.

The external features of the shell were described in 

detail by Ulrich and Bassler (1904, p. 119). In the 

specimens at hand, the submedian ridgelike swelling is 

weak on the elongate specimens (T. evax oblongula), 

but weak on the shorter ones. The surfaces of the valves 

are coarsely reticulate, with prominent nodes occurring 

principally at junctions of reticulating ridges, but also 

along their crests in some areas.

Hinge of right valve consists of an anterior high tooth 

bearing a depression on its ventral slope; a postjacent 

deep rounded socket; a long interterminal very minutely crenulate groove that expands into a shallow 

elongate socket at its posterior end; and a posterior high 

rounded tooth bearing several indistinct markings on 

its flattened summit. Hinge of left valve not observed.

Muscle scar lies in a large depression that externally 

forms the anteromedian swelling; scar consists of a 

subvertical row of several spots, but additional details 

could not be observed because of poor preservation. 

Inner lamellae rather broad; inner margin and line of 

concrescence are separated except along midportioii of 

ventrum. About 30 radiaPcanals occur about anterior 

end, mostly in pairs; posterior and ventral radial canals 

fewer but not clearly visible. Normal canals widely 

spaced, terminating interiorly in deep pits. A narrow 

groove for reception of a corresponding ridge on left 

valve borders free margins of right valve.

Length of a male left valve (pi. 3, fig. 1) 0.94 mm., 

height 0.50 mm.; length of a female left valve (pi. 3, 

fig. 3) 0.85 mm., height 0.50 mm.

Remarks: The shape, ornamentation, and hingement 

identify this species with Trachyleberis Brady, as 

emended by Sylvester-Bradley (1948, p. 794). The 

species is present in the middle and lower Miocene of 

North Carolina. Perhaps T. evax oblonffula (Ulrich

and Bassler) is a male dimorph and the specimens considered by Ulrich and Bassler to be typical of the species 

are female dimorphs. The writer does not agree with 

van den Bold (1946, p. 90) that T. oblongula represents 

the adult of the species and that the shorter but equally 

high forms are immature molts. A specimen believed 

to be an immature molt is figured on plate 3, fig. 2.

Occurrence: Trachyleberis evax occurs in the Esso 

Standard Oil Co. Hatteras Light well no. 1 middle 

Miocene at 810-820 feet (U.S.N.M. 561416) and below, 

lower Miocene at 1,200-1,210 feet (U.S.N.M. 560773), 

and in questionable Oligocene or lower Miocene 

at 1,540-1,550 feet (U.S.N.M. 561417). The species 

was described by Ulrich and Bassler (1904, p. 119) 

from the Calvert formation at Plum Point, Md., and 

was also reported from the Chesapeake group at Yorktown, Va.

Van den Bold (1946, p. 90) reports the species from 

8 localities in the Oligocene of Cuba, but it is not evident 

from his illustrations (pi. 10, figs. 19a-d) that lie is 

dealing with T. evax. There are no exterior views and 

the line drawings of the interiors of several specimens 

do not reveal the prominent, rounded posterior hingetooth characteristic of the species.

Trachyleberis rosetta Swain, n. sp. 

Plate 3, figure 7

Shell subquadrate in lateral view; dorsal margin 

nearly straight, about three-fourths of shell length; 

ventral margin slightly convex, converging posteriorly 

with respect to dorsum; anterior margin broadly 

rounded, truncate above; posterior margin more narrowly rounded. Left valve larger than right, greatest 

overlap at anterodorsal marginal bend. Surface has 

large, numerous pustules, widely spread, strongly elevated, and bearing 4 to 5 small papillae at their crests; 

between the pustules, surface covered by small papillae. 

Each valve has a narrow depressed, unornamented median area. Terminal margins bear a row of small 

pustules.

Hingement and other internal features not observed.

Length of holotype 0.85 mm., height 0.52 mm., thickness 0.47 mm.

Relationships: The only specimen obtained was 

found in association with Trachyleberis evax (Ulrich 

and Bassler) which it resembles in shape, but the papillate pustules are more widely spaced, tiny pustules cover 

the surface between the larger ones, and the low longitudinal ridge is lacking.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 840-850 feet, middle Miocene, U.S.N.M. 

560636.
CENOZOIC OSTRACODA 29

Trachyleberis? martini (Ulrich and Bassler) 

Plate 3, figures 8, 15

Cythere martini Ulrich and Bassler, 1904, Maryland Geol. Surv.

Miocene Vol., pp. 112-113, pi. 36, figs. 11-15. 

Cythereis martini (Ulrich and Bassler), Swain, 1948, Maryland

Dept. Geol., Mines, and Water Res., Bull. 2, p. 196, pi. 12,

figs. 16, 17.

Shell subquadrate in lateral view; highest about onefourth from anterior end; dorsal margin made sinuous 

by the high anterocardinal angle and postdorsal projection of valve surface; ventral margin nearly straight, 

posteriorly converging slightly toward dorsum; anterior 

margin broadly rounded, extended below, and bearing a 

fringe of tiny spines along ventral two-thirds; posterior 

margin narrower, rounded and finely spinose below, 

concave above. Left valve slightly larger and extending 

beyond the other at cardinal angles.

Free margins bear a narrow rim, bounded on its inner 

side by a narrow groove; both ridge and groove are distinct, except midventrally. Area enclosed by submarginal grooves coarsely reticulate; the pits elongated 

longitudinally. Just anterior of middle is a low swelling with a faint furrow behind it. A ridge, slightly 

more prominent than others of the reticulum extends 

sinuously from near post-cardinal angle obliquely and 

forward. Two other similar more prominent ridges 

occur behind median swelling above midheight. Small 

eye tubercles lie beneath anterior cardinal angles.

Hinge of right value consists of an anterior, ovate, 

coarsely crenulate tooth and postjacent small socket, a 

narrow finely crenulate interterminal groove, and a 

posterior elongate tooth whose surface is irregular but 

not crenulate. Hinge of left valve the antithesis of 

right, but interterminal bar is only faintly crenulate in 

a few places. Line of concrescence and inner margin 

nearly coincide; inner lamellae rather broad. Marginal 

pore canals numerous; about 30 in anterior half of shell; 

some occur in pairs, others are single.

Length of figured specimen 0.61 mm., height 0.31 mm., 

thickness 0.27 mm.

Remarks: In general shape and in surface ornamentation this form resembles Trachyleberis Brady, but the 

anterior hinge tooth and socket are crenulate as in 

Cythereis Jones. The posterior tooth and socket, 

although irregular, are not crenulate. The specimen 

figured here (plate 3, fig. 8) differs from some examples 

of T. martini in that it is more nearly equivalved, lacks 

the smooth posterior end and the postventral nodelike 

swelling. In the writer's collection from the same zone 

of the subsurface of Maryland are examples both of 

typical T. martini and of forms identical with those 

described here. The atypical specimens from Maryland

927335—52———3

are generally smaller than typical T.\ martini and 

probably represent immature molts, but the specimens 

from North Carolina are evidently mature.

Occurrence: Upper Miocene, Esso Standard Oil Co., 

Hatteras Light well no. 1, 210-220 feet, U.S.N.M. 

560T76; North Carolina Esso well no. 2, 290-300 feet; 

Edenton Naval Air Base well no. 1, 30 feet, U.S.N.M. 

560778; Edenton no. 4 well, 45 feet, Middle Miocene, 

U.S.N.M. 560777; Edenton no. 1 well, 50-55 feet, 

U.S.N.M. 560779, 560637; Williamston test well no. 2, 

90-95 feet, U.S.N.M. 560781. Lower Miocene, Hatteras 

Light well no. 1, 1,160-1,170 feet, U.S.N.M. 560780. 

The species occurs in the Choptank and Calvert formations of Maryland, the Chesapeake group at Yorktown, 

Va. (Ulrich and Bassler, 1904, p. 113), and in the Calvert formation of the subsurface of Maryland (Swain, 

1948, p. 196).

Trachylebris? cf. T. micula (Ulrich and Bassler) 

Text figure Bl

Cythere micula Ulrich and Bassler, 1904, Maryland Geol. Survey, 

Miocene, p. 116, pi. 36, figs. 18-20.

Tlie present specimen differs from T. ? martini (Ulrich and Bassler) in its smaller size and weaker 

ornamentation. Trachyleberis micula may include 

immature molts of T. martini.

Occurrence: Upper Miocene, Esso Standard Oil Co., 

Hatteras Light well no. 1, 170-180 feet, U.S.N.M. 

560728; Calvert formation of Maryland and the Chesapeake group of Virginia.

Trachyleberis? cf. T? angulata (Sars) 

Plate 3, figures 9-12

Cythereis angulata Sars, 1865, Oversight Forhandlingar Norges 

Ostracoda, Videnskabsselskabet, Christiana, p. 40.

Cythere clathrata nuda Brady, 1886, Zool. Trans., vol. 5, p. 377, 

pi. 59, figs. 9,10.

Cythere angulata (Sars), Brady, 1868, Mon. Recent British 

Ostracoda, p. 409, pi. 26, figs. 39-42. Brady, Grosskey, and 

Robertson, 1874, Post-Tertiary Entomostraco, Paleontographical Soc., p. 162, pi 4, figs. 21-24, pi. 10, fig. 22. Brady 

and Norman, 1889, Roy. Dublin Soc. Trans., vol. 4, ser. 2, 

pt. 2, p. 165.

Not Hemicythere angulata (Sars), Sars, 1923-1928, Curstacea 

of Norway, p. 187, pi. 86. fig. 2.

Shell subovate in lateral view; dorsal margin nearly 

straight, about 0.7 of shell length; greatest height at 

anterodorsal marginal bend, about one-fourth from anterior end; ventral margin slightly convex, converging 

posteriorly toward dorsum; anterior margin broadly 

rounded, extended below, slightly truncate above; posterior margin narrowly rounded, extended below, 

slightly angulate above. Left valve larger than right,
30 OSTRACODA FROM WELLS IN NORTH CAROLINA

overlapping and extending beyond the other most in 

anterodorsal region.

Valves have distinct marginal rims. A low swelling, 

bearing several pits lies slightly below and in front of 

center; a smaller swelling lies just behind and above 

the other. A low dorso-median ridge lies parallel to 

dorsal and postdorsal margins, and the ventral surface 

bears a narrow longitudinal ridge; posterior terminations of these two ridges elevated. Surface within marginal rim coarsely reticulate. Eye tubercles below anterodorsal marginal bend, distinct, and surrounded by 

a low swelling.

Hinge of right valve consists of an anterior high reniform tooth; a postjacent deep socket; an interterminal 

crenulate groove expanding posteriorly to form a shallow, elongate socket; and a posterior high oval tooth. 

Hinge of left valve consists of an anterior large socket, 

a postjacent rounded tooth; a strong interterminal 

crenulate bar ending in a small blunt tooth; and a posterior oval oblique socket.

Muscle scar lies on the posterior slope of a large submedian internal depression. It is composed of a subvertical row of 3 or 4 elongate parallel spots, and at 

least three more anterior spots. Inner lamellae broadest anteriorly; inner margin and line of concrescence 

only slightly separated. Pore canals not clearly 

observed.

Length of a figured left valve (pi. 3, fig. 9) 0.77 mm., 

height 0.48 mm.

Remarks: In outline and hingement this species resembles -Hemicy there Sars, but the submedian swelling, 

submarginal ridges terminating in blunt elevations, and 

the muscle scar pattern ally it to Trachyleberis with 

which it is here tentatively placed. The specimens at 

hand are close to "Cythereis" macropora Sars in general shape and ornamentation. The status of Tf angur 

lata is obscured by the fact that Sars (1928, p. 187) 

referred it to Hemicythere, but his description of the 

shell, and his illustrations (pi. 86, fig. 2) deal with an 

entirely different form.

Occurrence: Edenton Naval Air Base well no. 4, 

Chowan County, N. C., 70 feet, middle Miocene; 

U.S.N.M. 560638; previously reported from the Quaternary of Europe, North America, and Spitzbergen.

Trachyleberis? cf. T? reesidei (Swain) 

Plate 3, figure 13

Cythereis reesidei Swain, 1948, Maryland Dept. Geology, Mines, 

and Water Kes., Bull. 2, p. 199, pi. 14, fig. 3.

Shell of the present specimen subovate in lateral view; 

dorsal margin slightly convex; greatest height about 

one-fourth from anterior end; ventral margin gently

convex, converging posteriorly toward dorsum; anterior margin broadly rounded, extended below, subtruncate above; posterior margin narrowly rounded, 

extended below. Left valve larger than right, greatest 

overlap in anterodorsal region.

Entire margin of each valve bears a narrow, well 

defined, slightly elevated rim. A broad sparsely pitted 

swelling lies slightly behind and below middle of shell. 

Low dorsal and ventral swellings lie on posterior slope 

of each valve; low ridges converge backward from 

each swelling. Surface of valves coarsely reticulate. 

Eye spots distinct, in low anterodorsal swellings. Internal features not observed.

Length of figured specimen 0.79 mm., height 0.47 mm., 

thickness 0.38 mm.

Remarks: The hingement, subcentral node, and marginal rims of this species relate it to Trachyleberis 

Brady, but the subovate outline prevents definite classification. Externally, the species is indistinguishable 

from T. ? reesidei (Swain) (1948, p. 199) from the subsurface Upper Cretaceous of Maryland. The present 

specimen from the upper Miocene of North Carolina 

may have been reworked, although there is no direct 

evidence. The stratigraphic position of the original 

occurrence in a core sample from Maryland is much 

more certain. In general shape and ornamentation the 

species is close to "Cythereis" theeU Skogsberg (1928, 

p. 106), but surface pitting differs slightly.

Occurrence: Harvey Neck well, Perquimans County, 

N. C., 43-46 feet; upper Miocene; U.S.N.M. 560639.

Trachyleberis? rukasi (Gooch) 

Plate 4, figures 8-10

Cythereis rukasi Gooch, 1939, Jour. Paleontology, vol. 13, p. 58(5, 

pi. 67, figs. 20-22.

Shell subquadrate in side view; highest one-fourth 

from anterior end; hinge margin nearly straight, about 

three-fifths of shell length; ventral margin nearly 

straight to slightly convex, converging posteriorly toward dorsum; anterior margin broadly rounded, 

slightly extended below; posterior margin subacuminately rounded, strongly extended below, truncate to 

slightly concave above. Left valve larger than right, 

extending beyond it most along dorsal slopes. Greatest 

convexity about median.

Free margins have a narrow distinctly elevated rim. 

Postventrally there are several low, blunt spines. 

Bounded, well-developed, eye tubercles at anterocardinal angles. Posterior third of shell compressed. Just 

in front of and below posterior cardinal angle is a prominent node from which an irregular, slightly nodose 

ridge extends forward and terminates about at
CENOZOIC OSTRACODA 31

midlength but well below dorsal margin; a short ridge 

extends downward from node, parallel to posterior margin. About one-third from posterior end along ventrum is a second prominent node that forms the posterior termination of a long midventral alaform ridge. 

A low ridge connects the two postmedian nodes. Just 

in front of middle is a prominent rounded node from 

which in dorsal, ventral, and posterior directions radiate 

6 or more irregular, in part bifurcated ridges; 3 of these 

ridges are higher and end in small nodes.

Hinge of right valve consists of an anterior rounded 

tooth and postjacent socket, supported by a thickened 

subjacent cardinal process; an interterminal narrow, 

very faintly denticulate groove; and a posterior rounded 

tooth. Hinge of left valve the antithesis of right, with 

the interterminal ridge faintly denticulate and formed 

of the narrowed valve edge. Muscle scar not clear but 

probably consists of four spots in a curved row around 

posterior and dorsal flanks of median depression on 

interior of each valve, and additional spots in anterior 

part of depression. Inner lamellae broadest anteriorly; line of concrescence and inner margin nearly 

coincide except in a narrow anterior zone. Radial 

canals numerous, some in twos or in threes.

Length of a figured specimen (plate 4, fig. 8) 0.52 

mm., height 0.27 mm., thickness 0.21 mm.

Remarks: This is one of the cythereisid group that 

bear dorsal and ventral longitudinal ridges terminating 

posteriorly in pointed nodes. It is uncertain whether 

Trachyleberis should include such forms.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 115-120 feet, middle Eocene; 

U.S.N.M. 560649. Described from the Cook Mountain 

formation, middle Eocene of central Louisiana.

Trachyleberis? sp. aff. T? communis aquia (Schmidt) 

Plate 4, figure 11

An abraded left valve doubtfully referred to Trachyleberis exhibits the following features:

Subquadrate in lateral view; highest about onefourth shell length from anterior end at position of the 

cardinal angle; hinge margin about two-thirds of shell 

length, slightly concave just behind antero-cardinal 

angle; ventral margin nearly straight or slightly convex, rising posteriorly in relation to dorsum. Anterior 

margin broadly rounded, slightly extended below and 

bearing five thick, blunt spines along its ventral half; 

posterior margin more narrowly rounded, bearing several blunt spines. Greatest convexity posteromedian.

Anterior end bears a broad, coarsely pitted, marginal 

ridge that merges with general surface of valve just 

behind anteroventral bend; a rounded, probably imperfectly preserved eye tubercle lies at anterodorsal 

angle. Posterior one-fiftH* of valve compressed, with a 

narrow marginal rim; surface merges smoothly with 

the elevated median portion of valve. Anteriorly, a 

broad furrow, having several low, narrow cross-ridges, 

separates marginal rim from median surface; an anterior boundary of the latter is an inconspicuous curved 

ridge. Medially, there is a large rounded swelling, 

with a rather broad longitudinal ridge extending backward to margin of raised median area; near its junction 

with median swelling, ridge somewhat narrower, and 

ventrad of this narrowness lies a low, ovate, broad swelling. Midventral and postventral surface forms a small 

alate expansion that terminates posteriorly in a rounded 

elevation. A similar low ridgelike expansion, parallel 

to hinge margin, also ends in a posterior elevation. 

General median surface coarsely pitted, perhaps in a 

reticulate pattern, although shell is so abraded that 

these details are not clear.

Hinge of left valve consists of an anterior deep socket 

and postjacent large blunt tooth, both supported beneath by a thickening of shell wall; a long thick interterminal ridge, bounded dorsally by a faint groove; and 

a posterior large socket. Inner lamellae fairly broad, 

inner margin uniformly curved, nearly coinciding with 

line of concrescence. Radial canals and musculature not 

observed.

Length of figured specimen 0.61 mm., height 0.36 mm.

Remarks: This shell resembles T.% commimis aquia 

(Schmidt) but is somewhat more quadrate, higher in 

proportion to length, and has a subsidiary swelling below the postmedian longitudinal ridge that is not present in the examples from Maryland.

Occurrence: Esso Standard Oil Co. N. C. Esso well 

no. 2,1,810-1,820 feet, lower Eocene; U.S.N.M. 560650. 

T. aquia was described from the Aquia formation 

(Paspotansa greensand marl member) of Maryland 

(Schmidt, 1948, p. 420).

Trachyleberis hilgardi (Howe and Garrett) 

Plate 4, figures 14-16, 20, plate 5, figures 2-5, 16

Cythereis hilgardi Howe and Garrett, 1934, Louisiana Dept.

Conserv. Geol. Bull. 4, p. 53, pi. 4, figs. 14, 15. 

Cythereis sieffristae Schmidt, 1948, Jour. Paleontology, vol. 22,

p. 421, pi. 64, figs. 5-9.

Shell subquadrate in lateral view; greatest height 

slightly more than one-fourth from anterior end; hinge 

margin nearly straight, about three-fourths of shell 

length, with well-defined cardinal angles of which the 

posterior is the more obtuse. Ventral margin slightly 

concave medially; anterior margin broadly rounded, 

extended below, fringed with a double row of small 

spines; posterior margin more narrowly rounded,
32 OSTRACODA FROM WELLS IN NORTH CAROLINA

obtusely angulated medially, and bearing about 5 coarse 

spines. Left valve larger than right, extending beyond 

the other most at cardinal angles. Valves moderately 

convex, greatest convexity about median.

Shells that are higher but not much longer are presumed to represent females.

Anterior end of each valve provided with a distinctly 

elevated, slightly nodose rim separated from spinose 

margin by a narrow pitted groove; near its dorsal termination, rim bears a lucid eye tubercle. Posteriorly 

and ventrally, marginal area of each valve bears a narrow ridge that swings inward and terminates in the 

highly ornamented valve surface, about one-fifth from 

anterior end; along its posterior course ridge bears marginal spines previously mentioned. Middle half of 

dorsal marginal area in each valve bears a nodose ridge 

that sends 4 or 5 spurlike ridges ventrally, and at its 

posterior termination bends ventrally nearly to midheight. About one-third from anterior end is a small 

reticulate median swelling, before which are several 

reticulating ridges. Behind the swelling is a narrow 

longitudinal ridge with several side spurs that merges 

with end of ventrally extended dorsal ridge. Below 

midheight is a long, discontinuous ridgelike elevation 

with many side spurs. At first glance the valves appear 

to be coarsely reticulate, but the writer believes that 

the ornamentation can be more accurately described 

as a pattern of ridges with accompanying spurlike 

projections.

All available shells of this description are firmly 

closed, and internal features could not be observed.

A figured specimen (plate 5, fig. 3) measures, length 

0.69 mm., height 0.35 mm., thickness 0.28 mm.

Remarks: According to Stephenson (1946, p. 340), 

this species is close to Trachyleberis stenzeli (Stephenson) but is less strongly spinose. T. siegristae 

(Schmidt) (1948, p. 421) from the Aquia formation 

of Maryland and Virginia is so similar that it is placed 

in synonymy. T. marginoreticulata (Swain) (1948, 

p. 197) lacks the longitudinal ridges of T. Mlgardi and 

is more completely reticulate. In these respects, T. 

marginoreticulata is like T. smithvillensis (Sutton and 

Williams) from the Weches formation of Texas, and 

although the latter is not so narrowly rounded posteriorly, the two species may prove to be synonymous.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 115-165 feet, middle Eocene U.S.N.M. 

560661, 560662, 560663; Esso Standard Oil Co. Hatteras 

Light well no. 1, 2,390-2,400 feet and 2,531-2,541 feet 

(core), lower Eocene U.S.N.M. 560651 and 560652; described from the Nanafalia formation, Wilcox group, 

at Pendleton, Tex. (Howe and Garrett, 1934, p. 53).

Trachyleberis stenzeli (Stephenson) 

Plate 4, figures 17, 18, 22, plate 5, figure 1

Cythereis Mlgardi Howe and Garrett, Stephenson, 1944, Jour.

Paleontology, vol. 18, p. 450, pi. 76, fig. 1. 

Cythereis stenseli Stephenson, 1946, idem., vol. 20, p. 340, pL 45,

fig. 5.

Shell subquadrate in side view; greatest height about 

one-fourth from anterior end; hinge margin straight, 

about three-fourths of shell length, terminating in well 

defined cardinal angles of which the posterior is the 

more obtuse. Ventral margin gently convex, converging posteriorly with dorsmn; anterior margin broadly 

rounded, slightly extended below, fringed with a double 

row of small spines; posterior margin narrowly 

rounded, acuminate medially, coarsely and strongly 

spinose below, weakly spinose above, with most of 

ventrally located spines bifurcating in well preserved 

specimens. Left valve larger than right, extending beyond the other most at cardinal angles. Valves moderately convex, greatest convexity slightly postmedian.

Anterior end bears a narrow, strongly elevated, discontinuous rim; dorsally, rim is high and unbroken; 

ventrally, it is lower and bears several blunt spines. 

Anterodorsally is a well-defined eye tubercle with postjacent bifurcate, blunt spines. Along hinge margin are 

three stout, bifurcating spines and behind them a 

fourth smaller spine. Posterior end and posterior half 

of ventrum bear a low, narrow, marginal rim on which 

lie the marginal spines. Median part of each valve 

separated from marginal rims by a rather broad shallow 

furrow, but furrow terminates antero-midventrally, in 

ventral part of more elevated median portion of shell. 

Latter area coarsely reticulate and bears a longitudinal 

submedian, somewhat oblique, ridgelike swelling with a 

conspicuous node just in front of shell middle, and has 

bluntly spinelike projections at several other positions. 

A more oblique and less conspicuous longitudinal ridge 

that bears several blunt, bifurcated spines or strong 

nodes, occupies a lower position. Postdorsally is a high, 

narrow transverse plate that in well-preserved specimens is concave toward the posterior. Male dimorphs- 

(pi. 5, fig. 1) relatively more elongate and slightly lestconvex than females (pi. 4, figs. 18, 22).

Hinge of left valve consists of an anterior deep 

rounded socket; a postjacent high rounded and bluntly 

pointed tooth; a long interterminal ridge that endsposteriorly as a small swelling and is bounded dorsally 

by a faint groove; and a posterior slightly ovate socket
CENOZOIC OSTRACODA 33

that opens ventrally just beneath blunt end of interterminal ridge. Hinge of right valve the antithesis of 

left. Inner lamellae bear faint concentric striae; line 

of concrescence and inner margin coincide. Radial 

canals not clearly observed. Muscle scar lies in a 

rounded anteromedian depression represented by the 

conspicuous external node, but its details could not be 

determined.

Length of a male dimorph (pi. 5, fig. 1) 0.87 mm., 

height 0.42 mm.

Remarks: In general shape, marginal spines, surface 

reticulation, longitudinal spiny ridges, and postdorsal 

short subvertical plate, all the present specimens resemble T. stenzeli (Stephenson).

Stephenson (1946, p. 340) had difficulty in distinguishing T. stenzeli from T. Mlgardi (Howe and Garrett) and the same problem is encountered in the North 

Carolina material. The two species are associated in 

the collections from the Naval Auxiliary Air Base well 

at Washington, N. C. The specimens here assigned to 

T. Mlgardi are not so spinose as T. stenzeli and their two 

longitudinal ridges bear spurlike projections on each 

side, rather than spines on the ridges themselves. Both 

species have a short postdorsal subvertical ridge or plate 

on each valve, but that of T. hilgardi is not strongly 

elevated.

Trachyleberis exanthemata (Ulrich and Bassler) of 

the Miocene, and T. orelliana (Stadnichenko) of the 

middle Eocene are very close to T. stenzeli but are not 

reticulate. The short, postdorsal, subvertical ridge or 

plate is present in T. exanthemata and also in several 

species of Cythereis in rocks as old as the Washita 

group, Lower Cretaceous (G. worthensis Alexander). 

The plate is well developed in C. austinensis Alexander 

of the Austin group, Upper Cretaceous, and C. midwayensis of the Midway group, Paleocene. Species possessing this feature may seem to form a natural group, but 

such a grouping would put together species that differ 

in several important characters. The ridge may be an 

isomorphous structure developed, perhaps as a strengthening or stabilizing feature, by several unrelated species 

of Cythereis and of Trachyleberis.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 100-135 feet, middle Eocene, 

U.S.N.M. 560654, 560655, 560660; Esso Standard Oil 

Co. Hatteras Light well no. 1, drill-cutting sample 

1,860-1,870 feet, middle Eocene, U.S.N.M. 560G53; 

2,390-2,400 feet, core, 2,531-2,541 feet, lower Eocene; 

previously recorded from the Weches formation, middle 

Eocene of Texas (Stephenson, 1946, p. 340).

Trachyleberis davidwhitei (Stadnichenko) 

Plate 4, figure 19, plate 5, figures 6, 7

Cythereis davidwhitei Stadnicbenko, 1929, Jour. Paleontology, 

vol. 1, p. 240, pi. 39, fig. 24. Stephenson, 1946, idem., vol. 

20, p. 336, pi. 44, fig. 5, pi. 45, fig. 12.

Cythereis quinquespinosa Sutton and Williams, 1939, idem., vol. 

13, p. 566, pi. 63, figs. 10, 11.

Shell subquadrate in lateral view; highest about onethird from anterior end; hinge margin straight, about 

four-sevenths of shell length, bounded by distinct but 

widely obtuse cardinal angles; ventral margin nearly 

straight, posteriorly converging moderately toward 

dorsum; anterior margin broadly rounded, slightly 

extended below, and bearing about 15 small stout spines 

on each valve; posterior margin narrowly rounded to 

subacuminate, extended medially, truncate to slightly 

concave above, its ventral portion bearing 7 or more 

stout spines of variable size, most of the larger ones 

bifurcated. Left valve slightly larger than right, extending beyond the other most at anterior cardinal 

angle. Females relatively higher than males.

Anterior end bears a marginal rim that terminates 

dorsally in a rounded transluscent eye tubercle, and 

dorsad of midheight is high and narrow; medially and 

ventrally it consists of a series of various-sized stout 

nodes and a few blunt spines. Posterior margin provided with a narrow, low, well-defined rim that extends 

forward beyond midlength. Shallow grooves bound 

each terminal marginal rim or inner side. Dorsal margins of each valve bear several long, thick spines; one 

lies just behind eye tubercle, three are in dorsal midsection, a fourth lies near posterior end of hinge and 

is connected to another spine just below it by a thickening of shell. Slightly in front of midlength a high, 

thick spine rises from a rounded swelling; two or three 

spines lie behind, and one or two spines lie below it; 

these spines form a row that dorsally curves slightly 

backward. A row of five stout spines along midventral 

surface more or less parallels the ventral margin. Between spines surface is smooth. Internal features not 

observed.

Length of a female (pi. 5, fig. 7) 0.68 mm., height 0.39 

mm., thickness 0.23 mm.; length of a male (pi. 5, fig. 6) 

0.68 mm., height 0.32 mm., thickness 0.21 mm.

Remarks: The present specimens closely resemble T. 

davidwhitei (Stadnichenko) in shape and ornamentation. The species, as described, has several spines just 

below posterior end of the hinge, whereas the North 

Carolina specimens have but one.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 115-120 feet, 130 feet, middle Eocene, 

U.S.N.M. 560664, 560665; Esso Standard Oil Co., North
34 OSTRACODA FROM WELLS IN NORTH CAROLINA

Carolina Esso no. 2, 1,610-1,620 feet, middle Eocene, 

U.S.N.M. 560772; North Carolina Esso no. 1, core, 

2,531-2,541 feet, lower Eocene, TT.S.N.M. 560656; and 

in the Yegua and Weches formations, middle Eocene of 

Texas (Stadnichenko, 1929, p. 240, Stephenson, 1946, 

p. 336).

Trachyleberis? pellucinoda (Swain)

Plate 4, figure 24, plate 5, figure 10

Cythereis pellucinoda Swain, 1948, Maryland Dept. Geol., Mines, 

and Water Res., Bull. 2, p. 200 (pi. 14, figs. 1, 2).

Shell subquadrate in lateral view; highest about onethird from anterior end; hinge margin nearly straight, 

about two-thirds of shell length; ventral margin sinuous, slightly concave medially; anterior margin broadly 

rounded, slightly truncate above; posterior margin narrowly rounded, extended below, truncate above. Left 

valve larger than right, extending beyond the other 

noticeably only at anterior cardinal angle and along 

postdorsal slope. Posterior end compressed; greatest 

convexity about median.

Free margins of each valve bear a narrow but distinct, 

moderately elevated rim; well-preserved specimens have 

a fringe of tiny spines along anterior, and along ventral 

half of posterior margins. Lucid, rounded eye spots 

situated anterodorsally. A narrow ridge, not well preserved in worn specimens, roughly parallels hinge margin but curves slightly away from margin near its 

anterior termination just above eye tubercle. A conspicuous longitudinal ridge extends from just below 

and behind eye tubercle posteriorly to a point below 

postcardinal angle, doubles back downward and forward 

to terminate at midlength; ridge highest posteriorly, 

where it forms the postdorsal node characteristic of the 

genus; three to four low, subvertical cross-ridges connect dorsal and ventral limbs of ridge. A conspicuous 

rounded, lucid node occupies a slightly anteromedian 

position; in front of node are three to four low, short, 

longitudinal ridges. Below the node a longitudinal 

ridge extends along nearly whole length of ventrum 

and posteriorly is expanded into a short ala. Raised 

median surface pitted in a roughly reticulate pattern.

Most internal characters obscured. Anteriorly, radial 

canals are numerous and appear to occur in groups of 

two or three.

Length of a figured specimen (pi. 4, fig. 24) 0.48 mm., 

height 0.26 mm., thickness 0.21 mm.

Remarks: The outline and the ornamentation of the 

present specimens agree closely with those of T. ? pellucinoda (Swain) from the Aquia formation of Maryland. 

On the holotype the ventral limb of the double postdorsal ridge is less strong than on the specimens described here, but the difference is not sufficient to 

distinguish the two forms.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 130 and 165 feet, middle Eocene, TT.S.N.M. 

560658 and 560669.

Trachyleberis? bassleri (Ulrich) 

Plate 5, figures 8,11-15

Cythereis tassleri Ulrich, 1901, Maryland Geol. Survey, Eocene, 

p. 120, pi. 16, figs. 19-21. Weller, 1907, Geol. Survey New 

Jersey Paleontology, vol. 4, p. 843, pi. 110, figs. 1-3. ?Cushman, 1925, Bull. Am. Assoc. Petroleum Geologists, vol. 9, 

p. 302, pi. 8, figs. 3a-c. Alexander, 1934, Jour. Paleontology, 

vol. 8, p. 219. ?Jennings, 1936, Bull. Am. Paleontology, vol. 

23, no. 78, p. 51, pi. 7, flgs. la-b. ?Van den Bold, 1946, 

Contrib. to the Study of Ostracoda, Amsterdam, p. 94, pi. 6. 

fig. 20. Schmidt, 1948, Jour. Paleontology, vol. 22, p. 422, pi. 

64, fig. 13. Swain, 1948, Maryland Geol. Survey, Bull. 2, 

p. 197, pL 13, fig. 7.

Cythereis toassleri lata Jennings, 1936, Bull. Am. Paleontology, 

vol. 23, no. 78, p. 52, pi. 7, figs. 2a-b.

Cythereis claibornensis Gooch, 1939, Jour. Paleontology, vol. 

13, p. 581, pi. 67, figs. 5, 6,10. Stephenson, 1946, idem., vol. 

20, p. 336, pi. 45, fig. 4.

Cythereis bassleri reticulolira Schmidt, 1948, idem., vol. 22, 

p. 423, pi. 64, figs. 14, 15.

Cythereis plusculmenis Schmidt, 1948, Jour. Paleontology, vol. 

22, p. 422, pi. 64, figs. 2-4.

ParacytTiereis potomaca, Schmidt, idem., p. 419, pi. 64, figs. 18,19.

Shell subquadrate in lateral view; highest about onefourth from anterior end; hinge margin nearly straight, 

about three-fourths of shell length; ventral margin 

straight, posteriorly converging moderately toward 

dorsum; anterior margin broadly and nearly uniformly 

rounded, fringed with small spines; posterior margin 

more narrowly rounded, truncate to slightly concave 

above, extended medially, and bearing several coarse 

spines below. Left valve slightly larger than right, 

extending beyond the other only at anterior cardinal 

angle.

Anterior and posterior one-fifth of each valve compressed; parallel to free margins of each valve is a narrow distinct rim. As viewed from beneath, opposing 

rims diverge from margins and just in front of midlength enclose a shallow depression formed by inward 

turning of valve edges, a podocopid characteristic (pi. 5, 

fig. 13). Anterodorsally, marginal rim ends in a small 

eye tubercle that is bounded above and on either side by 

a narrow groove. A narrow ridge rises near anteroventral marginal bend, extends backward and upward with 

increasing height, thus forming a small midventral ala; 

at a point about one-third shell length from posterior 

end (where it attains its greatest altitude) ridge bends 

abruptly toward dorsum, extends obliquely to near 

posterocardinal angle, then bends acuminately and
CENOZOIC OSTRACODA 35

extends forward and slightly downward to nearly onethird shell length from anterior end. In most specimens 

there is a slight dip in ridge just in front of its posterodorsal angulation. Anteromedially is a large, high, 

rounded node, steepest on its posterior slope. Entire 

surface within marginal rims, coarsely reticulate. In 

front of median node in most specimens are three short 

longitudinal ridges of which the most ventral is the 

strongest. Above and before submedian node in a large, 

(and possibly worn) shell that lacks anteromedian 

ridges reticulation has a slightly spiral arrangement 

(pi. 5, fig. 8).

Internal features not observed in the examples from 

North Carolina. The hingement of specimens from the 

subsurface of Maryland has been described (Swain, 

1948, p. 197).

Remarks: The writer considers the present specimens 

conspecific with T.\ bassleri (Ulrich) from the Aquia 

formation at Upper Marlboro, Md. Ulrich remarked 

(1901, p. 121), "considering that the specimens studied 

present considerable variation in surface sculpture, it is 

possible that they represent more than a single specific 

type." Ulrich's types have only weak anteromedian 

longitudinal ridges, possibly because of abrasion, and 

are most like figure 8, plate 5 of this paper. The other 

specimens of the present collection have the short anteromedian ridges preserved in various degrees of perfection. The best preserved shells have the strongest 

ridges. Comparison with hypotypes shows them to be 

conspecific with T.\ claibornensis (Gooch) (1939, p. 

581). This species is therefore placed in synonymy 

with T.\ b as si eri. Trachyleberisl plusculmenis 

(Schmidt) (1948, p. 422) is a slight variant of typical 

T. ? bassleri in that there are two and not three ridges in 

front of the median node. It thus resembles T. ? bicarinata (Swain) (1946, p. 376) which is, however, much 

more strongly sculptured. TJ bassleri reticulolira 

(Schmidt) (1948, p. 423) closely resembles Ulrich's 

syntypes of T. ? bassleri. Paracythereis potomaoa 

(Schmidt) (1948, p. 419) appears to be based on somewhat abraded specimens of an immature molt stage of 

T.% lassleri.

The generic position of the species is in doubt. The 

terminal elements of the hinge are not crenulate as in 

Cythereis and the species is therefore closer to TracJiyleberis Brady as emended (Sylvester-Bradley, 1948, p. 

794). In common with T.\ rukasi (Gooch) and some 

other cythereisid ostracodes, TA bassleri differs from 

typical Trachyleberis in possessing well defined dorsal 

and ventral longitudinal ridges that terminate posteriorly in elevated nodes. It may prove advantageous to 

erect a genus including such forms.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 100 and 165 feet, middle Eocene, 

U.S.N.MT 560666, 560667; Esso Standard Oil Co. N. C. 

Esso well no. 2, 1,610-1,620 feet, middle Eocene, 

U.S.N.M. 560771. It occurs in the Aquia formation of 

Maryland and Virginia (Ulrich, 1901, Schmidt, 1948, 

Swain, 1948), in the Claiborne group of Texas and 

Louisiana (Gooch, 1939, Stephenson, 1946). In a collection obtained by F. S. MacNeil in Sec. 15, T. 3 N., R 

19 E., Coffee County, Ala., just below Pea River bridge, 

T. ? ~bassleri is associated with T. ? vicksburgensis (Howe 

and Law), T. weaveri (H. and L.), and other fossils of 

Oligocene age. Presence of the species in the Mt. 

Laurel and Navesink formations, Upper Cretaceous, of 

New Jersey (Jennings, 1936, p. 51) is questionable— 

Jennings' illustrations are of a form that appears to lack 

the postmedian transverse ridge at the anterior margin 

of the compressed portion of the shell. Van den Bold 

(1946, p. 94) tentatively identified T. ? bassleri from the 

Paleocene and Eocene of Guatemala and British Honduras. Its range is Paleocene (?) to Oligocene.

Trachyleberis smithvillensis (Sutton and Williams) 

Plate 5, figure 9

Cythereis smithvillensis Sutton and Williams 1939, Jour. 

Paleontology, vol. 13, p. 564, pi. 63, figs. 18-20. Stephenson 

1947, idem., vol. 21, p. 580.

CytJiereis orelliana (Stadnichenko), Stephenson, 1946, idem., 

vol. 20, p. 338: (Not) Stadnichenko, 1927, Jour. Paleontology, vol. 1, p. 236, pL 39, figs. 8-10.

Shell subquadrate in lateral view; greatest height 

about two-sevenths from anterior end; hinge margin 

straight, about four-sevenths of shell length; ventral 

margin nearly straight, slightly concave medially, posteriorly converging moderately toward dorsum; anterior margin broadly rounded, slightly truncate above 

and fringed with many small spines; posterior margin 

narrowly rounded, subacuminate at midheight, strongly 

truncate above, and bordered by stout spines, some of 

which are bifurcated. Left valve slightly larger than 

right, extending beyond the other only along dorsal 

slopes. Valves moderately convex, greatest thickness 

median. Anterior and posterior ends of shell compressed.

Anterior margin with spinose. rim that ends just behind ventral marginal bend, and ends dorsally by the 

conspicuous eye tubercle; an high node lies just behind 

tubercle. Posterior end has a narrow rim from which 

project thick submarginal spines, and which extends 

along ventrum nearly to midlength. Surface of valves 

coarsely reticulate and spinose; spines rise from crests 

and junctures of reticulating ridges but without discernible pattern. Internal structures not observed.
36 OSTKACODA FROM WELLS IN NORTH CAROLINA

Length of figured specimen 0.68 mm., height 0.34 

mm., thickness 0.29 mm.

Remarks: In general shape and in coarsely spinose 

reticulate surface the present specimens resemble T. 

smithvillensis (Sutton and Williams) of the Weches 

formation. T. sdbinensis (Howe and Garrett) (1934, 

p. 55) from the Wilcox group is similarly reticulate, 

but lacks the spines and the dorsal and ventral margins 

are more nearly parallel. T. parexanthemata (Swain) 

(1946, p. 377), is spinose but possesses short ventral 

alae and is not reticulate.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 130 feet, middle Eocene, U.S.N.M. 560668; 

Weches formation, middle Eocene at Smithville, Tex.; 

Wilcox group, lower Eocene at Sabinetown, Tex.

Trachyleberis mundcrffi Swain, n. sp. 

Plate 5, figure 19, plate 6, figure 4

Shell subquadrate in lateral view; highest about onefourth from anterior end; hinge; margin nearly 

straight, about three-fifths of shell length; ventral 

margin slightly sinuous, posteriorly converging dorsum ; anterior margin broadly rounded, extended below, 

and fringed with two rows of tiny spines that extend 

around ventral bend; posterior margin narrower than 

the anterior, subtruncate, obtusely angulated at its 

dorsal and ventral bends. No complete specimens were 

found, but left valve is relatively higher at those places 

and presumably extends beyond right at ends of hinge.

Middle of each valve higher than ends; posterior end 

the more compressed. A fairly continuous narrow rim 

parallels free margins. Middle section of ventral rim 

double; around anteroventral bend rim is broken into 

about 4 nodes; at posterior end rim consists of a row 

of blunt nodes that become sparse above midheight; 

an oblique eye tubercle lies at anterodorsal termination 

of marginal ridge. A shallow trough separates marginal rim from raised median surface. Parallel to 

hinge margin is a low ridgelike swelling with about 5 

nodes: posterior node elongate with two weak downward spurs; next two nodes shorter and with stronger 

spurs; fourth node small and without a spur; fifth node 

forming dorsal termination of a subvertical ridge that 

extends to a point just below midheight and forms posterior boundary of raised portion of valve. A second 

longitudinal, irregular, and somewhat nodose ridge extends from below midheight obliquely backward nearly 

to edge of raised portion of valve and ends just above 

midheight; several spurs project from this ridge and 

in front of midlength it is enclosed within a submedian 

enlarged, pitted, thickened, swelled area of shell that is 

characteristic of genus; a narrow curved ridge extends

from area to eyespot. A third longitudinal ridge forms 

ventral boundary of raised portion of valve, and gives 

the shell a flattened aspect when viewed ventrally. The 

ridge consists mainly of about 7 nodes, of which the 

middle 3 or 4 send spurs toward the dorsum.

Hinge of right valve consists of an anterior high 

pointed tooth and postjacent small socket, a narrow 

nondenticulate interterminal groove, and a posterior 

low, narrow tooth that is elongated parallel to valve 

margin. Hinge of left valve the anthithesis of right. 

Muscle scar consists of a slightly anteromedian subvertical row of four tiny spots; other spots not observable. 

Inner lamellae rather narrow, broadest anteroventrally; 

line of concrescence and inner margin separate terminally, coincident ventrally. Pore canals not clear. 

• Length of a right valve (pi. 5, fig. 19) 0.69 mm., 

height 0.40 mm.

Relationships: There is very close relationship in 

surface ornamentation between T. mwidorffi and T. 

linospinosa (Sutton and Williams) (1939, p. 566) from 

the Weches formation of Texas. However, in that 

species the longitudinal ridges are not as high, the 

ventral ridge does not give a flattened aspect to the 

ventral surface of the shell, the posterior boundary of 

the raised median portion of the valves merges more 

evenly into the compressed posterior end, there are 

more numerous minor ridges on the valve surface, the 

submarginal furrow is not continuous ventrally, and 

the posterior margin is more pointed. In general shape 

and distribution of surface ridges, G. mimdorfji is closely 

related to several Cretaceous Gythereis, such as G. hazzardi Israelsky (1929, p. 19) and G. bicornis Israelsky 

(idem.), but small differences in surface ornamentation 

permit distinction of this new species. Trachyleberis 

exanthemata (Ulrich and Bassler), (1904, p. 117) of 

the Miocene bears rows of coarse nodes rather than 

longitudinal ridges, but otherwise is closely similar.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 60 feet, upper Miocene, U.S.N.M. 560672, 

560675. Edenton Naval Air Base well no. 1, Chowan 

Co., N. C., 55 feet, middle Miocene, U.S.N.M. 560782.

Trachyleberis pidgeoni (Berry) 

Plate 6, figure 1

Cytheridea pidgeoni Berry, 1925, Am. Jour. Sci., 5th ser., no. 9,

p. 485, figs. 7, 8. 

Cythereis pidffeoni (Berry), Schmidt, 1948, Jour. Paleontology.

vol. 22, p. 421, pi. 62, figs. 2-6.

Occurrence and remarks: The figured specimen 

(U.S.N.M. 560673) was obtained from the Naval 

Auxiliary Air Station well, Washington, N. C., at a 

depth of 115-120 feet, where it is associated with
CENOZOIC OSTRACODA 37

Haplocytheridea montgomeryensis (Howe and Chambers), Trachyleberis 1 rukasi (Gooch) and other characteristic Eocene ostracodes. C. pidgeoni has been 

reported from the Monmouth formation, Upper Cretaceous, and its present occurrence probably is due to 

reworking. The species was not found in undoubtedly 

Cretaceous beds in other wells, suggesting that it may 

have been restricted to a nearshore facies of the 

Cretaceous.

Trachyleberis? cf. T.? triplistriata (Edwards) 

Plate 6, figures 2,3

Cythereis triplistriata Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 522, pi. 87, figs. 24-26.

A collection of ostracodes from the upper Miocene 

Duplin marl, Natural Well, N. C., submitted by Mr. 

Mundorff, yielded the specimens discussed here. They 

resemble the holotype of T. ? triplistriata Edwards, but 

are coarsely pitted. Examination of the types reveals 

no pitting, and possibly they are immature molts or 

recrystallized shells. In the present collections, a specimen resembling the types was obtained from the Edenton Naval Air Base well no. 1, 45 feet, in the upper 

Miocene.

Ostracodes identified by Alexander (1934, p. 220) as 

Cythereis prestwichiana Jones and Sherborn from the 

Midway group, Paleocene, of Texas, are nearly identical 

with the present specimens, but they have a narrower 

posterior portion of the curving median ridge, and the 

posterior end of the ventral ridge is higher. Perhaps 

these slight differences are insufficient to make the 

Miocene specimens a distinct species. In hingement 

both forms resemble Trachyleberis Brady rather than 

Cythereis Jones. Other very similar species, G. austinensis Alexander (1929, p. 99) and C. paraustinensis 

Swain (1948, p. 199) occur in the Upper Cretaceous of 

Texas and Maryland, respectively.

Trachyleberis exanthemata (Ulrich and Bassler) 

Plate 6, figure 5

Gythere exanthemata Ulrich and Bassler, 1904, Maryland GeoL 

Survey, Miocene, p. 117, pi. 36, figs. 1-5.

Cythereis exanthemata marylandica, Howe and Huff, 1935, Florida Dept. Conserv. Geology Bull. 13, p. 18, pi. 1, figs. 1-5, 

pi. 4, fig. 7.

Cythereis exanthemata (Ulrich and Bassler), van den Bold, 

1946, Contrib. to the Study of Ostracoda, Amsterdam, p. 

88, pi. 10, fig. 2. Swain, 1948, Maryland Dept. Geology, 

Mines, and Water Res., Bull. 2, p. 204, pi. 12, figs. 14, 15.

This coarsely nodose and spinose form is widely distributed in the Miocene deposits of the Atlantic coastal 

region. It shows considerable range in its ornamentation, and a variety has been recognized, T. essanthemata

gomillionensis (Howe and Ellis) (1935, p. 19). Closely 

related forms in earlier Tertiary deposits are T. stenzeli 

(Stephenson) (1946, p. 340), and T. Ulgardi (Howe 

and Garrett) (1934, p. 53). T. mwidorffi Swain, n. sp., 

from the middle and upper Miocene, is very similar to 

T. exanthemata but medially has a longitudinal nodose 

ridge, rather than just a row of nodes or spines.

Occurrence: Edenton well no. 1, Chowan County, 45 

feet, Edenton no. 4 well, 45 feet, Naval Auxiliary Air 

Station well, Washington, N. C., 60 feet, both upper 

Miocene U.S.N.M. 560676 and 560774; Harvey Neck 

well, Perquimans County, 46 feet, middle Miocene 

U.S.N.M. 560775. The species occurs in the Calvert formation of Maryland (Ulrich and Bassler, 1904, p. 117; 

Swain, 1948, p. 204), in the Choptank formation of 

Maryland (Ulrich and Bassler, 1904, p. 117), in the 

Chesapeake group of Virginia (Ulrich and Bassler, 

1904, p. 117), in the Choctawhatchee formation of 

Florida (Howe and others, 1935, p. 18), and in the 

Miocene of Cuba and Guatemala (van den Bold, 1946, 

p. 88).

Trachyleberis vaughani (Ulrich and Bassler) 

Plates 6, figures 6, 7

Cythere vaughani Ulrich and Bassler, 1904, Maryland Geol. 

Survey, Miocene, p. 109, pi. 38, figs. 25-27.

Cythereis vaughani (Ulrich and Bassler), Howe and others, 

1935, Florida Dept. Conserv., Geol. Bull. 13, p. 25, pi. 3, 

figs. 24, 25, pi. 4, fig. 13. Coryell and Fields, 1937, Am. Mus. 

Novitates 956, p. 9, fig. lOa. Edwards, 1944, Jour. Paleontology, vol. 18, p. 522, pi. 87, figs. 27, 28. Van den Bold, 

1946, Contrib. to the study of Ostracoda, Amsterdam, p. 

88, pi. 10, fig. 1.

The external characteristics of the species were described in detail by Edwards (1944, p. 522), and additional information concerning the internal features is 

given here.

Hinge of right valve consists of an anterior pointed 

tooth and postjacent elongate shallow socket, an iuterterminal shallow, narrow, finely crenulate groove, and 

a posterior reniform tooth whose posterior lobe is 

higher. Hinge of left valve the antithesis of right. 

Inner lamellae rather uniformly broad, line of concrescence and inner margin nearly coincide; in the specimen examined there is anteriorly a broad calcified extension of the inner lamellae beyond the line of concrescence. Radial canals very numerous about entire 

periphery and much crowded in anterior border. Several canals bifurcate. Muscle scar not clearly observed. 

Marginal zone of each valve provided with a rabbetjoint interlocking process.

Occurrence: Harvey Neck well, Perquimans County, 

43-57 feet, middle and upper Miocene, U.S.N.M. 560677,
38 OSTRACODA FROM WELLS IN NORTH CAROLINA

560787, 560788; Esso Standard Oil Co. Hatteras 

Light well no. 1, 330-34:0 feet, upper Miocene. 

Other occurrences of the species are: Chesapeake group, 

James Kiver, Va. (Ulrich and Bassler, 1904, p. 109); 

Choctawhatchee formation of Florida (Howe and 

others, 1935, p. 25); Duplin marl of North Carolina 

(Edwards, 1944, p. 522).

Trachyleberis? rugipunctata (Ulrich and Bassler) 

Plate 6, figure 8

Oythere rugipunctata, Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene, p. 118, pi. 38, 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. 

Favellarugipunctata (Ulrich and Bassler), Edwards, 1944, Jour.

Paleontology, vol. 18, p. 524, pi. 88, figs. 5, 6. Van den Bold,

1946, Contrib. to the study of Ostracoda, Amsterdam, p. 100,

pi. 10, fig. 3.

The external features of the species have been described. Internal features of a typical specimen in the 

present collection are as follows:

Hinge of right valve consists of an anterior high 

pointed tooth and postjacent deep oval socket, an interterminal faint groove, and a posterior large, rounded, 

somewhat crenulate tooth; hinge of left valve consists of 

an anterior deep socket and postjacent high, pointed 

tooth; an interterminal narrow bar bounded dorsally by 

a faint groove, and a posterior large, coarsely crenulate 

socket. Along the straight portion of hinge, the slight 

groove in right valve simply overlaps the extended and 

slightly rabbeted edge of left valve. Muscle scar lies 

within deep anteromedian depression that externally 

produces a rounded eminence; it consists of a main 

group of five elongate spots of which the more anterior 

three form a subvertical row; in front of main group are 

two spots, the lower one a doublet. Inner lamellae 

fairly broad, line of concrescence and inner margin 

nearly coincide.

Remarks: Present knowledge is insufficient to distinguish this species from Trachyleberis as emended 

(Sylvester-Bradley, 1949, p. 794), and it is also doubtful 

that Favella Coryell and Fields (1937, p. 8) as it has 

been defined, differs sufficiently from Trachyleberis to 

permit its recognition. The species is tentatively classified as Trachyleberis rather than as Favella (Edwards, 

1944, p. 524) because of its shape, hingement, subcentral 

node, and compressed posterior end with anteriorly 

adjacent high dorsal and ventral areas. However, the 

muscle scar differs from that of many species of 

Trachyleberis in which the main element is a single 

subvertical row of pits.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 60 feet U.S.N.M. 560678, Edenton Naval 

Air Base well no. 1, 30-^35 feet U.S.N.M. 560785, Edenton well no. 4, 49 feet, Esso Standard Oil Company 

Hatteras Light well no. 1,320-330 feet U.S.N.M. 560784, 

N. C. Esso no. 2,130-140 feet U.S.N.M. 560786, all upper 

Miocene; Cape Lookout well, Carteret County, N. C., 

75-100 feet, middle Miocene U.S.N.M. 560783; Hatteras 

Light no. 1,1,210-1,220 feet, lower Miocene. Previously 

recorded from the Chesapeake group, James River, Va. 

(Ulrich and Bassler, 1904, p. 118), the Choctawhatchee 

formation of Florida (Howe and others, 1935, p. 23), 

the Duplin marl of North Carolina (Edwards, 1944, p. 

524), and the Miocene of Cuba, Guatemala, and British 

Honduras (van den Bold, 1946, p. 100).

Genus BUNTONIA Howe, 1935

Cythereisl Howe and Pyeatt, 1934, in Howe and Garrett, Louisiana Dept. Conserv. Geol. Bull. 4, p. 50; 1935, in Howe and 

Chambers, idem., Bull. 5, p. 33.

Buntonia Howe, 1935, Louisiana Dept. Conserv. Geol. Bull. 5, 

p. 22. Stephenson, 1947, Jour. Paleontology, vol. 21, p. 579.

Pyricythereis Howe, 1936, in Howe and Law, idem., Bull. 7, p. 65. 

Sutton and Williams, 1939, Jour. Paleontology, vol. 13, p. 569. 

Stephenson, 1944, idem., vol. 18, p. 453. Van den Bold, 1946, 

Contrib. to Study of Ostracoda, Amsterdam, pp. 30, 103. 

Stephenson, 1946, Jour. Paleontology, vol. 20, p. 329.

Buntonia howei (Stephenson) 

Plate 2, figures 25-27

Pyricythereis howei Stephenson, 1946, Jour. Paleontology, vol.

20, p. 330, pi. 42, figs. 16, 17. 

Buntonia howei (Stephenson), Stephenson, 1947, idem., vol. 21,

p. 579.

The external features of the present specimens are 

those of the species as described in detail by Stephenson (1946, p. 330).

Hinge of right valve consists of an anterior large, 

blunt tooth and postjacent socket; an interterminal, 

narrow, finely denticulate groove; and a posterior large, 

strongly elevated, rounded tooth. Hinge of left valve 

consists of an anterior deep socket and postjacent large 

tooth; an interterminal faintly denticulate bar f ormect 

of the extended and slightly thickened valve edge; and 

a posterior deep socket. Inner lamellae moderately 

broad, line of concrescence and inner margin nearly 

coincide; marginal pore canals rather numerous, apparently simple. Muscle scar obscured by matrix.

Length of a figured specimen (pi. 2, fig. 26) 0.48 mm., 

height 0.22 mm.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 115-120 feet, middle Eocene, U.S.N.M. 

560630. Described from the Weches formation, Claiborne group, at Smithville, Tex. (Stephenson, 1946, p. 

330).
CENOZOIC OSTRACODA 39

Buntonia? cf. B.? lacunosa (Jones) 

Plate 7, figure 21

Cythere lacunosa, Joaes, 1856, Tertiary Bntomostraca, Paleontographical Soc., p. 31, pL 3, figs. 5a-b.

Shell subelliptical in side view; highest about one 

third from anterior end; hinge margin nearly straight, 

more than half of shell length; ventral margin nearly 

straight, slightly concave medially; anterior margin 

broadly rounded, somewhat extended and finely spinose 

below; posterior margin more narrowly rounded, truncate above. Left valve slightly larger than right, ventrally extended beyond the other. Valves moderately 

convex, greatest thickness posteromedian.

Posterior margin and posterior three-fifths of ventral 

margin of each valve provided with a rounded rim and 

on its inner side an adjacent groove. Anterior end bears 

a deep narrow groove, lying close to margin. An inconspicuous low median node present on right valve 

but not on left valve of specimen at hand, possibly 

removed by abrasion. Surface bears coarse scattered 

pits, some of which are arranged in rows parallel to 

margins.

Length 0.57 mm., height 0.24 mm., thickness 0.22 mm.

Remarks: This small, perhaps abraded specimen, conforms in shape and general surface features to Buntonia Howe, but its internal characteristics have not 

been observed. It is closely similar to Oy there lacunosa 

Jones, except that, perhaps as a result of abrasion, it 

lacks, the prominent median node.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 130 feet, middle Eocene, U.S.N.M. 560704. 

B. ? lacunosa (Jones) was described from the Pliocene 

and Recent of England and Norway (Jones, 1856, 

p. 31).

Buntonia? planibasilis (Ulrica and Bassler) 

Plate 3, figures 4,5

Cythere plantbasilis Ulrich and Bassler, 1904, Maryland Geol. 

Survey Miocene vol., p. 99, pi. 38, figs. 1-3.

The external features of the present specimens are as 

described by Ulrich and Bassler. Dimorphism in the 

species is suggested by proportionally shorter, higher 

female shells (pi. 3, fig. 5) and longer, lower male shells 

(pi. 3, fig. 4).

Hinge of left valve as follows: an anterior very deep, 

rounded socket above an ocular depression, and defined 

postventrally by a delicate spurlike projection or by a 

continuous bar, and anteriorly by a rounded beadlike 

elevation; a postjacent rounded tooth; a long noncrenulate bar; and a posterior oblique socket. Hinge of right 

valve not observed.

Muscle scar median and consisting of a vertical row of 

four spots and one more anterior spot. Inner lamellae 

broadest anteriorly; inner margin smooth, nearly coinciding with line of concrescence. Radial canals numerous, with a few paired, and a few bifurcated near outer 

margin. In one specimen radial canals occur around 

entire free margin and penetrate shell beneath posterior 

hinge socket.

Length of a male left valve (pi. 3, fig. 4) 0.98 mm., 

height 0.55 mm.; length of female left valve (pi. 3, fig. 5) 

0.89 mm., height 0.53 mm.

Remarks: The hinge of this species is like that in 

Trachyleberis Brady, but in the subpyriform outline 

and generally more convex valves it resembles Bu-ntonia 

Howe. Buntonia? mcguirti Howe from the Vicksburg 

group and Red Bluff clay of the central Gulf region is 

very close to B.f planibasilis, but is more rounded posteriorly and less convex medially than that species. In 

both forms the anterior hinge socket of the left valve lies 

above an ocular depression, separated from it by a delicate spur or a complete ridge. Closely related species 

are "Cythere" septentrionalis Brady and C. marabilis 

Brady of the Quaternary, and C. laquaeta Jones of the 

Pliocene and Pleistocene. The whole group is rather 

closely related to the Cretaceous genus Protocythere 

Triebel in general form, but the latter bears a prominent 

anteromedian elevation and a median longitudinal 

ridge.

Occurrence: Esso Standard Oil Co. N. C. Esso well 

no. 2, 320-330 feet, upper Miocene, U.S.N.M. 560634; 

described from the Chesapeake group at James River, 

Va. (Ulrich and Bassler, 1904, p. 99).

Buntonia? cf. B.? garretti (Howe and McGuirt) 

Plate 3, figure 6, plate 4, figures 4-6

Cythereis garretti Howe and McGuirt, 1935, Florida Dept. 

Conserv. Geol. Bull. 13, p. 20, pi. 3, figs. 17-19, pi. 4, figs. 

5, 15.

The relationships of the specimens from the Miocene 

of North Carolina illustrated here are problematical. 

In shape, hingement, other internal features, and general pustulose surface the specimens resemble Buntonia 

Howe and are like B.f garretti Howe and McGuirt. 

They seem to be a little more finely pustulose than that 

species. In all other features except details of hingement they are identical with Buntonial okeechobiensis 

(Swain) from the Ocala limestone of the subsurface of 

Florida (Swain, 1946, p. 778, pi. 54, figs. lOa-b). The 

right ~ valve hinge o of the North Carolina form consists

of an anterior rounded, high tooth, a postjacent deep 

socket, a narrow interterminal ridge and an oblique, 

posterior, elevated tooth. In B.\ okeechobiensis the
40 OSTRACODA FROM WELLS IN NORTH CAROLINA

liinge of the right valve consists of an anterior rounded 

tooth and postjacent socket, an interterminal narrow 

ridge formed by the valve edge and a posterior angulate 

tooth formed of an elevated and thickened portion of the 

valve margin at its post-dorsal bend. The general similarity between B. ? garretti and B. ? okeechobiensis evidently is a matter of isomorphism and they are 

distinguished by the minor but clear difference in the 

hinge structure.

The muscle scar of the present form lies in an anteromedian depression and consists of a subvertical row of 

four spots and at least one more anterior spot.

Length of figured specimen, a right valve 1.01 mm., 

height 0.58 mm.

Occurrence: Esso Standard Oil Co. North Carolina 

Esso well no. 2, 400-410 feet, upper Miocene, U.S.N.M. 

560635, 560647; Esso Standard Oil Co. Hatteras Light 

well no. 1, 900-910 feet, middle Miocene, U.S.N.M. 

560646.

Buntonia? mcguirti (Howe)

Plate 4, figures 2, 3

Gythereis mcguirti Howe, 1936, Louisiana Dept. Conserv., Geol.

Bull. 7, p. 48, pi. 4, figs. 21, 22. 

Wrachycythere ~betzi Jennings, Swain, 1948, Maryland Dept.

Geology, Mines, and Water Res., Bull. 2, p. 209, pi. 14, figs.

12, 13.

Shell subovate in lateral view; greatest height about 

one-fourth from anterior end; dorsal margin nearly 

straight, about three-fifths of shell length; ventral margin gently convex, converging strongly backward with 

dorsum; anterior margin broadly rounded, slightly extended below, bearing three rows of marginal spines 

along its ventral half; posterior margin narrowly 

rounded, subacuminate, extended medially, slightly 

truncate above, weakly spinose. Valves nearly equal in 

size; greatest convexity behind center of shell.

Surface of each valve strongly swollen behind midventral area, and in some specimens midventral margin 

obscured by overhang of shell. Ends compressed; the 

anterior bears a narrow low marginal ridge; corresponding feature on posterior end is barely discernible. 

Inflated portion of valve surface weakly and coarsely 

reticulated; ventrally there are weak longitudinal 

ridges. Male ? proportionally longer than female ?, but 

contrary to usual relationships, the two forms are about 

the same height.

Hinge of right valve consists of an anterior rounded 

tooth and postjacent socket, an interterminal narrow 

groove, and a posterior oval tooth. Hinge of left valve 

the antithesis of right. Other internal features not 

clear.

Length of a figured male? dimorph (pi. 4, fig. 2) 0.95 

mm., height 0.53 mm.; length of a female? dimorph (pi. 

4, fig. 3) 0.87 mm., height 0.55 mm.

Remarks: The generic relationships of this species 

are obscure, but in a general way it is close to Buntonia 

Howe and is here provisionally included in that genus. 

Anticythereis van den Bold is similar in shape and 

hingement, but is said to have the right valve larger 

than the left (van der Bold, 1946, p. 30), a characteristic 

that is subject to question judging from the description 

of the genotype A. reticulata (Jennings). Jennings 

(1936, p. 56) erected Pseudocythereis with P. reticulata 

Jennings as genotype. Van den Bold, observing this to 

be an instance of homonymy with Pseudocytherein 

Skogsberg (1928) introduced Anticythereis for Jennings' specimen and provided the following generic 

summary:

Carapace small, subrectangular. Right valve larger than left, 

overlapping along the dorsal margin. Line of concrescence and 

inner margin coincide. Hingement like Cyfhereis (Range) 

Upper Cretaceous.

According to Jennings (1936, p. 56):

The righ valve overlaps the left on dorsal magrin; strongest 

development in center of dorsal region; left valve overlaps right 

on ventral margins, strongest near center.

It is not at all clear that the right valve in P. reticulata 

is larger than the left, and the overlap relationships are 

inconspicuous in dorsal view (Jennings, 1936, pi. 7, 

fig. lOb). Jennings' figure lOa suggests that the left 

valve is the larger, but this impression may be due to 

poor orientation of the specimen.

The writer believes that in this general group, including #.? mcguirti (Howe), B.\ okeechobiensis (Swain) 

and Leguminocythereis clarkana (Ulrich and Bossier) 

the valves are nearly equal in size and that slight differences in comparative size of the valves are not of 

generic value. Jennings described the hinge of "Pseudocythereis" as consisting of terminal teeth with an 

intervening groove in the right valve, and terminal 

sockets with an intervening ridge in the left. He illustrates (Jennings, 1936, pi. 7, fig. lOd) but does not 

mention crenulation of the interterminal ridge in the 

left valve. It is not known that such hinge crenulation 

is common in Anticythereis van den Bold ( =Pseudocythereis Jennings). Crenulation of the hinge was used 

to distinguish Butonia Howe (= Pyticythereis Howe) 

and in part to distinguish Paracythereis Jennings, 1936, 

(not Paracythereis Delachaux, 1928, or Paracythereis 

Elofson, 1941), but the writer considers crenulation 

alone an insufficient basis for generic distinction. 

Anticythereis has not been well defined, and although
CENOZOIC OSTRACODA 41

the present species is closely related, the writer hesitates 

to place it in that genus.

Occurrence: Esso Standard Oil Co., Hatteras Light 

well no. 1, core 1,740-1,750 feet, middle Eocene, 

U.S.N.M. 560645. The species was described (Howe 

and Law, 1936, p. 49) as "the commonest and most 

distinctive ostracode in the Vicksburg group" of Louisiana, Mississippi, and Alabama. The same or a 

closely related species was identified as Brachycythere 

betzi Jennings by Swain (1948, p. 209) from the subsurface Eocene of Maryland.

Genus FAVELLA Coryell and Fields, 1937 

Favella cf. F. mesacostalis Edwards

Favella mesacostalis Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 524, pi. 88, figs. 1-4.

One left valve of an immature specimen was obtained. 

The hinge consists of an anterior, somewhat elongate, 

very faintly crenulate socket, an interterminal bar 

formed of the valve edge, and a posterior slightly crenulate? socket. The hinge resembles that of Oligocythereis Sylvester-Bradley (1948, p. 795), a Middle 

Jurassic genus, and supports his theory of the evolu- 

" tion of the hinge in the Cytheracea. Other writers have 

observed the same relationships in the molts of several 

species of Cythereis and related genera. In mature 

specimens of F. mesacostdlis (Edwards 1944, p. 523), 

the left valve hinge consists of an anterior rounded high 

tooth, postjacent socket, long interterminal groove and 

posterior curved tooth.

Occurrence: Esso Standard Oil Co., Hatteras Light 

no. 1 well, 160-170 feet, upper Miocene, U.S.KM. 

560748. Described from the Duplin marl (upper 

Miocene) near Lumberton, N. C.

Genus PTERYGOCYTHEREIS Blake, 1929

Pterygocythereis washingtonensis Swain, n. sp.

Plate 4, figure 21

Shell elongate-subquadrate in side view; highest onefourth from anterior end at position of anterocardinal 

angle; hinge margin nearly straight, with small posterior cardinal node; ventral margin nearly straight, 

converging posteriorly with dorsum; anterior margin 

broadly and uniformly rounded, bearing 12 or more 

thick, blunt spines; posterior margin narrower, 

strongly truncate to slightly concave above midheight, 

and bearing several thick blunt spines below. Left 

valve slightly larger than right, extending beyond the 

other at cardinal angles; along straight portion of hinge 

right valve extends slightly beyond left.

Broad, low, anterior marginal rim merges with general surface of valve a short distance behind ventral 

bend. Lower rounded part of posterior end bears a narrow, rather elevated rim that extends anteriorly along 

ventrum, nearly to midlength, but is less elevated in 

front of ventral bend. Posterior and postventral areas 

of valves strongly compressed. Midventral surface of 

each valve strongly expanded, with short, high, postmidventral alae, that in ventral view give the shell the 

arrowhead outline characteristic of the genus. An inconspicuous ridge parallels dorsal margin and a high, 

rounded, elevation lies at posterior cardinal angle. Anterior half of each valve variably pitted; two subparallel 

rows of large pits lie behind anterior marginal rim; 

subcentrally, and below elongate low swelling with 

postjacent shallow groove, are 6 or 8 pits in two adjacent 

longitudinal rows; an oblique, narrow furrow consisting essentially of a row of closely spaced small pits 

lies below an anteromedian smooth area; dorso-medially 

are many small pits arranged in fairly good longitudinal rows; just beneath anterior cardinal angle are 

two oblique rows of tiny pits. A low ridge extends 

dorsally from anteromedian smooth area nearly to 

anterocardinal angle, terminating in an obscure swelling that may be an eye tubercle. Most of posterior half 

and of alate midventral area smooth; a few small pits 

occur postdorsally. Two or three short spurs extend 

forward from inner edge of posterior marginal rim.

Internal features not visible in the specimen at hand.

Length 0.74 mm., height 0.33 mm., thickness 0.26 mm.

Relationships: The general subquadrate form and 

ventral alae of this species clearly ally it to Pterygocythereis Blake. It is not so strongly pitted as the 

Eocene P. forbesiana (Miiller), and as compared to P. 

cornuta (Roemer) and var. americana (Ulrich and 

Bassler) it has a pitted surface, weaker dorsal ridges, 

more rounded alate expansions and a more uniformly 

curved anterior margin.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 135 feet, middle Eocene, U.S.N.M. 560657.

Pterygocythereis cornuta americana (Ulrich and Bassler)

Cythereis cornuta americana Ulrich and Bassler, 1904, Maryland 

Geol. Survey, Miocene, p. 122, pi. 37, figs. 29-33.

Cytliereis (Pterygocythereis) americana Howe and others, 1935, 

Florida Dept. Conserv., Geology Bull. 13, p. 26, pi. 2, figs. 19, 

21-24, pi. 4, fig. 24. Swain, 1948, Maryland Dept. Geology, 

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

A single right valve, from the upper Miocene is 

externally typical of the species. The hinge of this 

specimen consists of an anterior elongate tooth and 

postjacent socket, an interterminal crenulate groove, 

and a posterior kidney-shaped tooth. Howe (1935, p.
42 OSTRACODA FROM WELLS IN NORTH CAROLINA

26) did not report crenulation of the inter-terminal area 

in specimens from the middle Miocene of Florida.

Occurrence: North Carolina Esso well no. 2, 280-290 

feet, upper Miocene, U.S.N.M. 560749. Described from 

the Calvert formation of Maryland.

Genus CAUDITES Coryell and Fields, 1937

Caudites jacksonvillensis Swain, n. sp.

Plate 5, figures 17, 18

The two left valves at hand show the following 

features:

Shell elongate-subovate in side view; highest about 

one-third from anterior end; dorsal margin gently 

convex; ventral margin slightly sinuous, concave medially; anterior margin broadly rounded, slightly concave 

at dorsal bend; posterior margin bluntly acuminate, 

greatly extended below, concave above. Convexity moderate ; ends compressed, especially the posterior.

A narrow low rim borders anterior and ventral 

margins; just above ventrum is a somewhat sinuous 

longitudinal ridge that is highest about one-third from 

posterior end; just below dorsum in posterior half 

of shell is a ridge that extends back to posterior compressed area, turns downward and becomes higher and 

broader above midheight, then narrows and joins 

ventro-longitudmal ridge; just anterior of midlength is 

a low swelling; two divergent ridges project forward 

from swelling, and another projects toward postdorsal 

region. Anteromedially is a small eye tubercle.

Hinge of left valve consists of an anterior very large, 

rounded, deep socket, and postjacent knoblike tooth; a 

long narrow interterminal bar, formed of the extended 

valve edge; and a posterior ovate socket. Inner lamellae 

of moderate width terminally; line of concrescence and 

inner margin slightly separated. Other internal features not clear.

Length 0.61 mm., height 0.32 mm.

Relationships: The new species is close to C. sellardsi 

(Howe and Neill), (Ho.we and others, 1935, p. 29) of 

the Choctawhatchee formation of Florida, but has 

ridges below and behind a median node, and the postdorsal ridge lies closer to the margin.

Occurrence: Jacksonville Tent Camp well no. 2, 

Onslow County, N. C., 103-110 feet, middle Eocene, 

U.S.N.M. 5606TO and 560671.

Genus ACFTICYTHEREIS Edwards, 1944 

Acuticythereis cf. A. laevissima Edwards

Acuticythereis laevissima Edwards, 1944, Jour. Paleontology, 

vol. 18, p. 519, pi. 87, figs. 4-11.

Occurrence: A crushed specimen, U.S.N.M. 560750 

that may belong to this species was found at a depth

of 46 feet, middle Miocene, in the well at Harvey Neck, 

Perquimans County, N. C. Described from the Duplin 

Marl, upper Miocene at Lumberton and other localities 

in North Carolina.

Acuticythereis laevissima punctata Edwards

Acuticythereis laemssima punctata Edwards, 1944, Jour. Paleontology, vol. 18, p. 520, pi. 87, figs. 12, 13.

One somewhat recrystallized specimen (U.S.N.M. 

560751) represents this variety. The weak pits in the 

posterior half of the left valve distinguish this form 

from A. laevissima Edwards.

Occurrence: Well no. 65 at Bogue, Carteret, N. C., 

230-245 feet, upper Miocene. The variety was originally obtained from the Duplin marl at Natural Well, 

N. C.

Acuticythereis cf. A. multipunctata Edwards 

Text figures 3m, n

Acuticythereis multipunctata Edwards, 1944, Jour. Paleontology, vol. 18, p. 520, pL 87, figs. 14-16.

This species closely resembles Cytherideis ashermani 

Ulrich and Bassler, but in the latter the left valve is 

more nearly equal-ended, the hinge consists of terminal 

interlocking grooves and flanges rather than rounded 

teeth and sockets, the inner lamellae are narrower, and 

the valves are more convex.

Occurrence: Upper Miocene, Esso Standard Oil Co., 

Hatteras Light well no. 1 at 610-620 feet, upper 

Miocene, U.S.N.M. 560728. Described from the Duplin 

marl of North Carolina.

Genus HEMICYTHERE Sars, 1925

Hemicythere conradi Howe and McGuirt

Plate 6, figures 9-12

Hemicythere conradi Howe and McGuirt, 1935, Florida Dept. 

Conserv., Geol. Bull. 13, p. 27, pi. 3, figs. 31-34, pi. 4, fig. 17. 

Edwards, 1944, Jour. Paleontology, vol. 18, p. 518, pi. 86, 

figs. 17, 18.

The external features of the species have been described. The hingement of specimens from the Duplin 

marl, Natural well, N. C., submitted by Mr. Mundorff 

is as follows:

Hinge of right valve consists of an anterior deep oval 

socket and postjacent strong rounded tooth; an interterminal thick bar, bounded dorsally by a rabbeted platform and step; and a posterior ovate deep socket. 

Hinge of left valve consists of an anterior strong 

rounded tooth and postjacent deep socket; an interterminal broad furrow, and a posterior strong, slightly 

reniform tooth. An immature left valve has an anterior elongate shallow socket, an interterminal finely 

crenulate bar, bounded dorsally by two rabbeted steps,
CENOZOIC OSTRACODA 43

and a posterior elongate shallow socket. The conspicuous anterior teeth of the adult form are lacking 

in the immature molt whose hinge resembles that of 

Orthonotocythere Alexander of the Cretaceous and 

Paleocene, and Hutsonia Swain of the Upper Jurassic. 

Occurrence: Esso Standard Oil Company Hatteras 

Light well no. 1, 160-170 feet U.S.N.M. 560753; North 

Carolina Esso well no. 2, 350-360 feet, upper Miocene 

U.S.N.M. 560764; Edenton Naval Air Base well no. 4, 

Chowan County, 88 feet U.S.N.M. 560760; Cape Lookout well, Carteret County, 75-100 feet U.S.N.M. 560762, 

middle Miocene; North Carolina Esso well no. 1,1,130- 

1,140 feet, lower Miocene. Kecorded from the Choctawhatchee formation of Florida (Howe, et al., 1935, 

p. 27), from the Duplin marl of North Carolina (Edwards, 1944, p. 518); present in the writer's collections 

from the Yorktown formation of Virginia.

Hemicythere sp. aff. E. conradi Howe and McGuirt

A single left valve represents this species. The surface ornamentation consists of concentric narrow ridges 

and pitted grooves. The middle part of the valve is 

abraded, but bears deep small pits. The hinge consists 

of an anterior deep elongate socket, postjacent high 

tooth, an interterminal finely crenulate groove, and a 

posterior elongate socket that contains 1 or 2 denticular 

elevations. Inner lamellae broad, line of concrescence 

and inner margin separate. Radial canals very numerous, present along entire free margin. Muscle scar not 

seen.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1,60-70 feet, Pleistocene, U.S.N.M. 560752.

Hemicythere oonfragosa Edwards 

Plate 6, figures 13,14

Hemicythere confraffosa Edwards, 1944, Jour. Paleontology, vol. 

18, p. 518, pi. 86, figs. 23-26.

This species has been described in detail. It is much 

more rare than H. conradi Howe and McGuirt, and it 

has not been found in deposits older than late Miocene.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 60 feet, upper Miocene, U.S.N.M. 

560680; Duplin marl (upper Miocene) of surface exposures in North Carolina.

Genus LEGUMINOCYTHEREIS Howe, 1936

Leguminocythereis cf. L. scarabaeus Howe and Law

Plate 6, figures 15,16

Leguminocythereis scarabaeus Howe and Law, 1936, Louisiana 

Dept. Conserv., Geol. Bull. 7, p. 63, pi. 4, figs. 12, 17, pi. 5, 

figs. 15-17.

Specimens (U.S.N.M. 560681) that are not well preserved, but which probably belong to this species, were

obtained by Mr. Mundorff from the Castle Hayne formation at Pollacksville, N. C. They are slightly less 

extended dorsally than is typical of the species. The 

species was described from the Vicksburg group, Oligocene, of Louisiana and Mississippi (Howe and Law, 

1936, p. 63).

Leguminocythereis clarkana (TTlrich and Bassler) 

Plate 6, figure 18

Cythere clarkana Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene, pp. 98, 99, pi. 35, figs. 1-10. 

Leguminocythereis clarkana (Ulrich and Bassler), Swain, 1948,

Maryland Dept. Geology, Mines, and Water Res., Bull. 2,

p. 207, pi. 13, fig. 6.

This has been adequately described. The well-preserved specimen (U.S.N.M. 560683) figured here is 

characterized by a pattern of broad, polygonal pits outlined by closely and finely spinose ridges.

Occurrence: Bogue well no. 65, Carteret County, 130 

feet, upper Miocene U.S.N.M. 560683; Esso Standard 

Oil Company Hatteras Light well no. 1, 880-890 feet, 

middle Miocene U.S.N.M. 560767; Karsten no. 1 Laughton well, 471-508 feet U.S.N.M. 560765; North Carolina 

Esso well no. 1, 1,210-1,220 feet, lower Miocene. The 

species was described from the Calvert formation of 

Maryland, and was reported from the Chesapeake group 

at Yorktown, Va. (Ulrich and Bassler, 1904, p. 99; 

Swain, 1948, p. 207).

Leguminocythereis white! Swain, n. sp. 

Plate 3, figures 14, 16-18, plate 4, figure 1.

Shell subelliptical to elongate-ovate in lateral view; 

highest about one-fourth from anterior end; dorsal 

margin nearly straight, about four-fifths of shell 

length; ventral margin slightly sinuate; anterior margin 

broadly rounded, truncate in cardinal region on female 

dimorphs; posterior margin somewhat more narrowly 

rounded. Left valve slightly larger than right. Greatest convexity in posterior third of shell.

A narrow ridge, highest anteriorly, parallels free 

margins of valve. Terminal and ventral areas bear an 

additional ridge within and nearly parallel to marginal ridge. A third, more interior curved ridge occupies anterodorsal area, and a fourth ridge lies in a 

postdorsal position between marginal ridge and the 

more interior principal ridge. An elongate curved 

depression occupies a median position on each valve 

behind a low anteromedian swelling. Postdorsal fourth 

of valves somewhat swollen, especially in female 

dimorph. Entire surface coarsely and deeply pitted, 

subreticulate; interspaces only about one-fifth width 

of pits.
OSTRACODA FROM WELLS EST NORTH CAROLINA

Hinge of right valve consists of an ovate, oblique, 

smooth tooth, a postjacent elongate shallow socket, a 

long, narrow interterminal smooth groove and a posterior elongate-ovate socket. About one-fourth from 

anterior end of hinge and below groove is a subtriangular thick process of uncertain function. It may indicate 

position of attachment of a ligament for opening valves 

as it follows a corresponding process in left valve. 

Hinge of left valve consists of an anterior elongate 

socket, a narrow interterminal ridge that bears a bulbous 

toothlike expansion at its anterior end, and a posterior 

elongate socket.

Muscle scar lies on the flanks of submedian internal 

depression corresponding to external swelling described 

above; it consists of a vertical row of four spots (of 

which the uppermost is rounded, the middle two 

elongate, and the lowermost one ovate) and two more 

anterior spots, the upper one rounded, the lower one 

elongate.

Inner lamellae rather broad, especially at anterior 

end; line of concrescence and inner margin nearly 

coincide. Radial canals few and widely spaced terminally , more numerous and closely spaced in anteroventral area.

Length of holotype (pi. 3, fig. 17) 0.71 mm., height 

0.37 mm.

Relationships: Gythere ovalis Brady (1880, p. 66), 

a Recent species closely resembles Leguminocythereis 

wTiitei in general shape and coarsely pitted surface, but 

lacks the prominent marginal ridges. Oythere cancellata Brady (1868, p. 62), also from the Recent, is 

similar but has prominent transverse curved ridges. 

Lowoconchat postdecliva Swain (1948, p. 194) from the 

Eocene of Maryland resembles the new species but has 

a more strongly developed median sulcus that reaches 

the dorsal margin, has several prominent transverse 

curved ridges, and is more compressed posteriorly. In 

general shape, hingement, musculature, sparse terminal 

radial canals and general ornamentation the present 

species resembles Leguminocythereis Howe. Legwmnocyfhereis clarkana (Ulrich and Bassler) from the 

Miocene of Maryland is more finely pitted, partly 

spinose, has wider interpit areas and lacks the marginal 

ridge pattern of the new species.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 60-70 feet, Pleistocene, U.S.N.M 560711; 

North Carolina Esso no. 2, 370-380 feet U.S.N.M. 

560710 and 1,400-1,410 feet, lower Miocene or Oligocene 

U.S.N.M. 560642, upper Miocene; Edenton Naval Air 

Base well no. 1, Chowan County, 55 feet U.S.N.M. 

560640 and 560641, Edenton no. 4 well, 88 feet, middle 

Miocene U.S.N.M. 560643.

Genus BRACHYCYTHERE Alexander, 1933

Brachycythere cf. B. martini Hurray and Hussey

Plate 6, figure 26

Brachycythere martini Murray and Hussey, 1942, Jour. Paleontology, vol. 18, p. 177, pi. 28, figs. 6, 10, text figs. 2, 8-10. 

Stephenson, 1946, idem., vol. 20, p. 333, pi. 44, fig. 21, pi. 45, 

fig. 24.

A single specimen was obtained. Length of the 

figured specimen is 1.12 mm., height 0.63 mm., thickness 

0.59 mm.

Occurrence: Esso Standard Oil Co. North Carolina 

Esso well no. 2, 1,610-1,620 feet, middle Eocene, 

U.S.N.M. 560689. In the Gulf region, the species occurs 

in the Claiborne and Jackson groups (Stephenson, 1946, 

p. 333).

Brachycythere marylandica (Ulrich) 

Plate 7, figure 1

Cythere marylandica TJlrieh, 1901, Maryland Geol. Survey,

Eocene, p. 119, pi. 16, figs. 16-18. 

Brachycythere nanafaliana Howe and Pyeatt, Howe and Garrett,

1934, Louisiana Dept. Conserv., Geol. Bull. 4, p. 48, pi. 3,

fig. 18, pi. 4, figs. 1-3. Murray and Hussey, 1942, Jour.

Paleontology, vol. 16, p. 180, pi. 28, figs. 11,12, text fig. 2. 

Brachycythere marylandica (Ulrich), Schmidt, 1948, Jour.

Paleontology, vol. 22, p. 416, pi. 63, figs. 17-20.

This species was described in detail by Schmidt (1948, 

p. 416), who also placed B. l>etzi Jennings (1936, p. 47) 

in synonmy. Swain (1948, p. 209) described a specimen 

from the subsurface of Maryland that he believed to 

represent B. betzi; that example differs in several 

respects from B. marylandica^ but may represent 

Cythereis ? mcguirti rather than B. l>et&i.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 175 feet, lower Eocene, U.S.N.M. 560690; 

also in the Aquia formation of Maryland (Ulrich, 1901, 

p. 119; Schmidt, 1948, p. 416), the Nanafalia and 

Hatchetigbee formations (Wilcox group) of Louisiana 

and Alabama (Howe and Garrett, 1934, p. 48; Murray 

and Hussey, 1942, p. 180).

Brachycythere cf. B. hadleyi Stephenson 

Plate 7, figures 7-9

Brachycythere hadleyi Stephenson, 1946, Jour. Paleontology, 

vol. 20, p. 333, pi. 44, fig. 23, pi. 45, fig. 23.

Several specimens strongly resembling this species 

were found. Several allied species of Brachycythere^ 

including B. hadleyi Stephenson, B. "bernardi Murray 

and Hussey, B. alata (Bosquet) and B. watervalleyensis 

Howe and Chambers, are distinguished by differences 

in development of the ventral alae, extension of the 

posterior end, degree of elongation of the shell, and
CENOZOIC OSTRACODA 45

curvature of the dorsal margin. The difficulty of distinguishing these species with certainty reduces their 

stratigraphic value. The present specimens seem to be 

most similar to forms of middle Eocene (Claiborne)

Length of a figured specimen (pi. 7, figs. 7, 9) 1.11 

mm., height 0.73 mm., thickness 0.68 mm.

Occurrence: Esso Standard Oil Co., North Carolina 

Esso well no. 2, 2,060-2,070 U.S.N.M. 560696 and 2,150- 

2,160 feet U.S.N.M. 560695, Paleocene(?), 1,800-1,810 

feet U.S.N.M. 560755, lower Eocene; 1,470-1,480 feet 

U.S.N.M. 560756, middle Eocene; Esso Standard Oil 

Co., Hatteras Light well no. 1, 1,740-1,750 feet, middle 

Eocene U.S.N.M. 560754. Described from the Weches 

formation at Smithville, Tex. (Stephenson, 1946, p. 

333).

Brachycythere cf. B. jessupensis Howe and Garrett 

Plate 7, figure 10

Brachycythere jessupensis Howe and Garrett, 1934, Louisiana 

Dept. Conserv., Geol. Bull. 4, p. 47, pi. 3, figs. 14, 16, 17.

Shell subovate in side view; highest about one-third 

from anterior end. Dorsal margin moderately convex; 

ventral margin slightly convex, sinuous in right valve, 

converging toward dorsum posteriorly. Anterior margin broadly rounded, extended below, slightly truncate 

above, finely spinose in ventral half; posterior margin 

narrowly rounded, extended medially. Left valve much 

larger than right, extending beyond the other around 

entire periphery, greatest extension dorsal. Valves 

strongly convex, greatest thickness slightly postmedian. 

Ends compressed in relation to strongly inflated midportion of shell.

Median area of each valve coarsely pitted. Ventral 

surface inflated to form rounded alate expansions; a 

low longitudinal ridge present at crest of each ala. A 

low swelling, representing eye tubercle lies at anterior 

cardinal angle, and is defined below by a narrow oblique 

sulcus that ventrally bounds ornamented portion of 

valve. Anterior end bears a narrow, indistinct, marginal rim. Internal features not observed.

Length of figured specimen 1.07 mm., height 0.63 mm., 

thickness 0.50 mm.

Remarks: This form resembles B. interrasilis Alexander (1934, p. 217) of the Midway group, but is somewhat more coarsely pitted and has less strongly elevated ventral longitudinal ridges. Probably it is conspecific with B. jessupensis Howe and Garrett, but 

diagnostic internal characters are not visible in our 

specimens.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 160 feet, middle Eocene, U.S.N.M. 560697.

927335—52———1

Described from the horizon of the Nanafalia formation, 

Wilcox group, at Fort Jessup, La. (Howe and Garrett, 

1934, p. 47).

Brachycythere sp.

An imperfect left valve identified as Brachycythere 

was collected. The dorsal portion of the valve is missing; the ventral portion bears an alaform midventral 

swelling that has a low ridge at its summit; surface 

apparently smooth.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well, no. 1, 330-340 feet, upper Miocene, N.S.N.M. 

560753.

Genus CYTHERETTA Miiller, 1894

Cytheretta porcella (Ulrich and Bassler)

Plate 4, figure 7

Cythere porcella, Ulrich and Bassler, 1904, Maryland Geol. Survey, Miocene, p. 106, pi. 36, figs. 26-33.

The general shape and the hingement ally this species 

to Cytheretta, and transfer to that genus is here made. 

The present smooth-surfaced single valve evidently is 

identical with C. porcella of the middle and upper 

Miocene of Maryland and Virginia. In some of the 

type specimens the posterior half of the valve is weakly 

pitted.

Length of figured specimen 0.74 mm., height 0.37 mm.

Occurrence: Esso Standard Oil Company, Hatteras 

Light well no. 1, 1,480-1,490 feet, lower Miocene, 

U.S.N.M. 560648; described from the Calvert formation, Plum Point, Md.; reported also from the Chesapeake group, Yorktown, Va.

Cytheretta cf. C. plebeia (Ulrieh and Bassler)

Cythere plebeiu Ulrich and Bassler, 1904, Maryland Geol. Surrey,

Miocene, p. 102, pi. 35, figs. 20-29. 

Oytheretta plebia (Ulrich and Bassler), Swain, 1948, Maryland

Dept. Geology, Mines, and Water Res., Bull. 2, p. 212, pi. 13,

figs. 3, 4.

A broken left valve, probably of this species was obtained. The species has been reported from middle 

Miocene deposits only, and the present specimen may 

have been reworked.

Occurrence: Pleistocene sands, Esso Standard Oil 

Co. Hatteras Light well no. 1, 60-70 feet, U.S.N.M. 

560712. Described from the Calvert formation of 

Maryland, and the Chesapeake group of Virginia.

Cytheretta? sp. aff. C. plebeia (Ulrich and Bassler) 

Plate 6, figure 17

Shell elongate-subovate in lateral view; greatest 

height about one-fourth from anterior end; hinge
46 OSTRACODA FROM WELLS IN NORTH CAROLINA

margin nearly straight, about three-fifths of shell 

length; ventral margin gently convex, posteriorly converging moderately toward dorsum; anterior margin 

broadly rounded, slightly extended below; posterior 

margin more narrowly rounded, slightly extended 

above. Left valve larger than right, overlapping and 

extending slightly beyond the other around entire 

periphery; greatest extension midventral; greatest 

overlap at cardinal angles. Valves rather strongly convex, greatest convexity in posterior half. Surface ornamented by medium-sized, irregularly disposed pits, 

most of which lie in posterior half; posteroventrally, 

some pits arranged in short concentric rows.

Hinge not observed. Muscle scar not clear but seems 

to consist of a medial row of several spots and two more 

anterior spots.

Length of figured specimen 0.87 mm., height 0.46 

mm., thickness 0.41 mm.

Remarks: The specimen differs from typical C. 

plebeia in the more uniformly ovate outline of the 

smaller right valve, and more uniform convexity in the 

ventral region. It is much less strongly pitted and 

more uniform in outline than G. burnsi (Ulrich and 

Bassler). The internal features of the single specimen 

are not fully known, so that its relationships are 

obscure.

Occurrence: Edenton Naval Air Base well no. 1, 

Chowan County, N. C., 45 feet, upper Miocene, U.S.N.M. 

560682.

Cytheretta inaequivalvis (TTlrich and Bassler)

Cythere inaequivalvis Ulrich and Bassler, 1904, Maryland Geol.

Survey, Miocene, p. 101, pi. 35, figs. 15-17. 

Cytheretta inaequivalvis (Ulrich and Bassler) Swain, 1948,

Maryland Dept. Geology, Mines, and Water Res., Bull. 2,

p. 213, pi. 13, fig. 5.

Occurrences Well no. 65 at Bogue, N. C., 130 feet. 

U.S.N.M. 560713, and Esso Standard Oil Co. Hatteras 

Light Well no. 1, 670-680 feet, U.S.N.M. 560714, upper 

Miocene. It occurs also in the Calvert formation, 

middle Miocene, of Maryland.

Cytheretta cf. C. bassleri Howe

Cytheretta ftassleri Howe, 1935, Florida Dept. Conservation, 

Geol. Bull. 13, p. 32, pi. 3, figs. 21, 22.

Occurrence: One specimen, from uppermost Miocene, 

Esso Standard Oil Co. Hatteras Light well no. 1, 160- 

170 feet, U.S.N.M. 560715. Described from the Area 

zone of the Choctawhatchee formation, middle Miocene, 

of Florida.

Cytheretta karlana Howe and Pyeatt 

Plate 6, figure 19

Cytheretta Jcarlana Howe and Pyeatt, Howe and others, 1935, 

Florida Dept. Conserv., Geol. Bull. 13, p. 34, pi. 1, figs. 30, 

34, pi. 3, figs. 3, 4.

Cytheretta reticulata Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 525, pi. 88, figs. 7-10.

The present example (U.S.N.M 560684) from the 

water well at Harvey Neck, Perquimans County, N. C., 

at a depth of 55-57 feet, middle Miocene, was compared 

with the type of G. reticulata Edwards and found to be 

conspecific. Specimens of G. karlana Howe and Pyeatt 

have not been examined, but published descriptions and 

illustrations show that it resembles G. reticulata so 

closely that they are probably conspecific. 

, Occurrence: Cytheretta karlana was described from 

the Chipola formation, lower Miocene of Florida (Howe 

and others, 1935, p. 34). A slightly smaller and more 

delicate variety, G. karlana var. choctawhatchiensis 

Howe and Taylor was described from the Area zone of 

the Choctawhatchee formation of Florida. G. reticulata 

was described from the upper Miocene Duplin marl, 

Duplin County, N. C. (Edwards, 1944, p. 525).

Cytheretta darensis Swain, n. sp. 

Plate 6, figures 20-22

Sthell subovate in side view; greatest height median; 

hinge margin nearly straight to gently convex, slightly 

more than half of shell length; ventral margin of left 

valve gently convex, that of right valve nearly straight 

and somewhat sinuous; anterior margin rounded, 

slightly extended below; posterior margin more narrowly rounded, extended medially, truncate above in 

left valve, slightly concave above in right valve. Left 

valve much larger than right, extending strongly beyond the other along ventrum, and overlapping rather 

strongly at antero-cardinal angle. Greatest convexity 

just behind midlength where valve surfaces, especially 

that of the right, are strongly swollen. Surface smooth, 

except for several weak longitudinal ridges in.ventral 

portion of left valve.

Internal features not observed because of poor preservation.

Length of holotype, a complete specimen (pi. 6, fig. 

20) 0.90 mm., height 0.53 mm., thickness 0.46 mm.

Relationships: This species lacks the pitted surface 

of G. plebeia (Ulrich and Bassler) of the Miocene, and 

the strong longitudinal ridges of G. aleasanderi Howe 

and Chambers of the upper Eocene. Gythereis? ever-
CENOZOIC OSTEACODA 47

greenica (Stadnichenko) (1927, p. 235) of the middle 

Eocene resembles it in shape and nearly smooth surface, 

but lacks the cytherettid overlap at the ends of the 

hinge.

Occurrence: Esso Standard Oil Co., Hatteras Light 

well no. 1, 1,740-1,750 feet, middle Eocene, U.S.N.M. 

560685 and 560686.

Cytheretta cf. C. alexanderi Howe and Chambers 

Plate 6, figures 23-25

Cytheretta alexanderi Howe and Chambers, 1935, Louisiana 

Dept Conserv., Geol. Bull. 5, p. 45, pi. 5, figs. 17-21, pi. 6, figs.

27, 28.

Shell elongate-subovate in lateral view; greatest 

height about one-third from anterior end; hinge margin 

slightly convex, a little more than half of shell length; 

ventral margin of left valve gently convex, that of right 

valve sinuous to slightly concave medially; anterior 

margin slightly extended medially; posterior margin 

more narrowly rounded, extended medially, concave 

near cardinal angle, and bearing small spines along 

ventral portion. Left valve much larger than right, 

extending strongly beyond other along ventrum, and 

overlapping at anterocardinal angle. Convexity of 

valves moderate, posterior end compressed; greatest 

convexity behind and slightly below middle.

Several longitudinal ridges and grooves present, some 

converging posteriorly; grooves bear scattered coarse 

pits; just beneath anterocardinal angle in each valve is 

a short, shallow, oblique sulcus.

Internal features not observed because of recrystallization of shell material.

Length of a figured specimen (pi. 6, fig. 25) 0.83 mm., 

height 0.46 mm., thickness 0.38 mm.

Remarks: The present specimen probably belongs in 

this species but its poor preservation prevents comparison of internal features. The surface ridges and 

grooves are somewhat less strongly developed than indicated in illustrations of C. alexanderi^ but this may be 

the result of imperfect preservation.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 100 feet, middle Eocene U.S.N.M. 560688; 

Esso Standard Oil Co. North Carolina Esso well no. 2, 

1,620-1,630 feet U.S.N.M. 560687. Described (Howe 

and Chambers, 1935, p. 45) from the Jackson formation, 

upper Eocene, at Creole Bluff, Montgomery County, La.

Genus BASSLERITES Howe, 1937

Basslerella Howe, 1935, Florida Dept. Conserv., Geol. Bull. 13,

p. 30 (preoccupied). 

Basslerites Howe, Howe in Coryell and Fields, 1937, Am. Mus.

Novitates 956, p. 11.

Basslerites cf. B. miocenicus (Howe) 

Plate 7, figures 5, 6

Basslerella miocenica Howe, 1935, Florida Dept. Conserv., Geol.

Bull. 13, p. 31, pi. 1, figs. 19, 24-26. ' 

Basslerites miocenicus (Howe), Howe, in Coryell and Fields,

1937, Am. Mus. Novitates 956, p. 11. Edwards, 1944, Jour.

Paleontology, vol. 18, p. 521.

Shell subquadrate in side view; highest about onefourth from anterior end; hinge margin nearly straight, 

about two-thirds of shell length, with well-defined cardinal angles; ventral margin gently convex, converging 

moderately backward with respect to dorsum; anterior 

margin broadly rounded, slightly extended below; posterior margin less broadly rounded, somewhat extended 

above. Left valve larger than right, overlapping the 

other rather strongly at ends of hinge, less strongly elsewhere. Surface nearly smooth, ventral slope bears a 

few faint, discontinuous, longitudinal ridges; other 

faint ridges parallel dorsal margin in posterior half. 

Internal features not observed.

Length of a figured specimen (pi. 7, fig. 5) 0.83 mm., 

height 0.46 mm., thickness 0.37 mm.

Remarks: External characteristics like those prescribed for B. miocenicus but as the internal features are 

unknown, the present assignment is tentative.

Occurrence: Williamston test well no. 2, Martin 

County, N. C., 90-95 feet, middle Miocene U.S.N.M. 

560694. Described from the Choctawatchee formation 

of Florida (Howe and others, 1935, p. 31). The types 

include specimens from the upper part of the formation 

and from the Area zone below.

Basslerites cf. B. gigauticus Edwards 

Text figures 3o-q

Basslerites giganticus Edwards, 1944, Jour. Paleontology, vol. 

18, p. 521, pi. 87, figs. 19-23.

Occurrence: One specimen (U.S.N.M. 560727) from 

the upper Miocene, Esso Standard Oil Co., Hatteras 

Light well no. 1, 170-180 feet; described from the 

Duplin marl near Lumberton, N. C.

Genus EOCYTHEROPTERON Alexander, 1935

Eocytheropteron? sp.

Plate 7, figure 16

Shell subquadrate in lateral view; highest about onefourth from anterior end; dorsal margin nearly 

straight, about two-thirds of shell length; ventral margin sinuate and converging posteriorly toward dorsum; 

anterior margin broadly rounded, extended below; posterior margin narrowly rounded. Ventral portion of 

shell swollen, especially the posterior third where
48 OSTRACODA FROM WELLS IN NORTH CAROLINA

enlargement overhangs ventral margin as weakly developed alae. Posterior end somewhat compressed.

Surface has a faint reticulate pattern of narrow 

ridges and broad minutely punctate interspaces.

Hinge of left valve consists of terminal, elongate, 

weakly crenulate sockets, an interterminal crenulate 

ridge, dorsad of which is a narrow groove. Muscle 

scar of single specimen found consists of a subvertical 

row of three elongate spots. Inner lamellae fairly broad 

anteriorly, narrower elsewhere; antero-ventrally, inner 

margin and line of concrescence widely separated. 

Radial canals few, flaring where they open along line 

of concrescence, giving it a scalloped outline.

Length of figured specimen, a left valve, 0.44 mm., 

height 0.25 mm.

Remarks: In general outline and weak alation this 

specimen resembles Eocytheropteron Alexander, but the 

hingement is that of Cytheropteron Sars. The ornamentation of the specimen differs from that of species of 

Cytheropteron familiar to the writer, and it may represent a new species. The small specimen found may be 

an immature molt.

Occurrence: Esso Standard Oil Co. North Carolina 

Esso well no. 2, 380-390 feet, upper Miocene U.S.N.M. 

560700.

Genus CYTHEROPTERON Sars, 1865

Cytheropteron cf. C. subreticulatum van den Bold 

Plate 7, figures 11, 13

Cytheropteron subreticulatum van den Bold, 1946, Contrib. to 

the Study of Ostracoda, Amsterdam, p. 113, pi. 14, flg. 6.

Shell subovate in side view; highest slightly anterad 

of midlength; dorsal margin moderately convex in left 

valve, less convex in right valve; ventral margin 

slightly convex, somewhat sinuous; anterior margin 

rounded, extended below, subtruncate above; posterior 

margin more narrowly rounded with a median blunt 

caudal extension. Left valve larger than right, greatest 

extension in middorsal region.

Midventral surface of each valve strongly inflated to 

form blunt alae; crests of alae occupied by low longitudinal ridges. Anteromedian portion of valve coarsely 

pitted; postermedian portion bears strong, sub vertically elongate pits and intervening short ridges. 

Marginal areas smooth. Posterior caudate portion of 

valves strongly compressed.

Hinge of right valve consists of terminal small teeth, 

separated by a long denticulate groove; hinge of left 

valve consists of terminal sockets and intervening thick 

denticulate bar. Inner lamellae fairly broad with a 

distinctly wider postventral area; inner margin and line 

of concrescence widely separated; radial canals few,

widely and irregularly spaced. Muscle scar obscured 

by matrix.

Length of figured right valve (pi. 7, fig. 11) 0.58 mm., 

height 0.35 mm.

Remarks: In most features this form resembles G. 

subreticulatwn, but van den Bold's drawing shows 

weaker ornamentation.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 60 feet, upper Miocene, U.S.N.M. 560698. 

Described from the Miocene of Cuba (van den Bold, 

1946, p. 113).

Cytheropteron cf. C. variosum Martin 

Plate 7, figures 12,14,15

Cytheropteron variosum Martin, 1939, Jour. Paleontology, vol. 

13, p. 178, pi. 22, figs. 7-9.

The specimens appear identical with Martin's species 

from the Claiborne group of the Gulf region. As compared to G. cf. C. subreticulatum, the present species 

possesses more strongly elevated ridges on the alae, is 

smaller, and more coarsely pitted. G. montgomeryensis 

Howe and Chambers (1935, p. 19) from the lower part 

Jackson formation in the Gulf states is closely similar 

in shape but is more weakly ornamented. Perhaps G. 

subreticulatum and some of the more or less smooth 

specimens included by Martin in C. variosum are conspecific.

Length of a figured specimen (pi. 7, fig. 12) 0.43 mm., 

height 0.26 mm., thickness 0.23 mm.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 135 feet, middle Eocene, U.S.N.M. 560699. 

Described from the Cook Mountain formation of Louisiana, and recorded in the McBean formation of Georgia, and the Gosport sand of Alabama.

Cytheropteron sp. (a) 

Plate 7, figure 17

Left valve subquadrate in side view; highest medially; dorsal margin gently convex; ventral margin 

nearly straight; anterior margin extended and narnowly rounded below, truncate above; posterior margin 

extended above as a broad caudal process. Shell 

strongly alate ventrally, and medially bears a depression 

on the alate expansion; anterior margin bears a narrow 

rim. Surface of specimen at hand consists of granular 

calcite that obscures its original finer details.

Hinge of left valve consists of terminal elongate 

sockets connected by a high, narrow, finely denticulate 

ridge. Other internal features obscured by recrystallization of shell and matrix.

Length of figured left valve 0.60 mm., height 0.32 mm.
CENOZOIC OSTRACODA 49

Remarks: In outline, small size, and smooth surface 

this form resembles Oytheropteron crassipinnatum 

Brady and Norman from the Recent of the North 

Atlantic region as figured by Sars (1928, p. 227) but in 

that species the alae are longer and more pointed. Sars' 

illustration shows weaker surface pits and sharper alae 

than were indicated by Brady and Norman. The single 

poorly preserved left valve at hand does not allow a 

complete analysis of the species.

Occurrence: Esso Standard Oil Co. Hatteras Light 

well no. 1, 320-340 feet, upper Miocene, U.S.N.M. 

560701.

Cytheropteron sp. (b)

A small, probably immature, right valve represents 

this genus. The ventral surface is strongly swollen but 

not crested. The median portion of the valve bears weak 

and irregular longitudinal ridges.

Occurrence: Lower Miocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, 1,220-1,230 feet, U.S.N.M. 

560716.

Genus CYTHEROMORPHA Hirschmann, 1909

Cytheromorpha cf. C. warneri Howe and Spurgeon

Plate 7, figures 18,19

Cytheromorpha warneri Howe and Spurgeon, 1935, Florida 

Dept. Conserv., Geol. Bull. 13, p. ll»pl. 2, figs. 5, 8, 9, pi. 4, 

fig. 4.

The specimens from North Carolina wells appear to 

be intermediate between O. warneri Howe and Spurgeon 

and C. warneri okal&osaensis Howe and Spurgeon in 

that the anterior half to two-thirds of the valve surface 

is pitted rather than reticulate. The entire surface is 

somewhat more finely ornamented than illustrated for 

C. warneri. The present species is also much like C. 

rosefieldensis Howe and Law of the Vicksburg group, 

but lacks the median ventral ridge of that species.

Length of a figured specimen (pi. 7, fig. 18) 0.57 mm., 

height 0.31 mm., thickness 0.21 mm.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 60 feet, upper Miocene, U.S.N.M. 560702; 

the species occurs in the Choctawhatchee formation of 

Florida, and the Calvert formation of Maryland 

(Howe and others, 1935, p. 12). C. warneri okaloosaensis occurs in the Shoal River formation of Florida and 

the Calvert formation of Maryland (idem., p. 13).

Cytheromorpha curta Edwards 

Plate 7, figure 22

Cytheromorpha ourta Edwards, 1944, Jour. Paleontology, vol. 

18, p. 516, pi. 86, figs. 19-22.

The example figured here was compared with the 

holotype and found to be conspecific. Except for short

length in proportion to height, it is very much like O. 

warneri Howe and Spurgeon, and may prove to be an 

immature molt stage or a dimorphic variation of that 

species. .

Length of figured specimen 0.42 mm., height 0.28 mm., 

thickness 0.18 mm.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 60 feet, upper Miocene, U.S.N.M. 560705; 

described from the Duplin marl near Lumberton, N. C.

Cytheromorpha cf. C. eocenica Stephenson 

Plate 7, figure 20

Cytheromorpha eocenica Stephenson, 1946, Jour. Paleontology, 

vol. 20, p. 311, pi. 43, fig. 9.

Shell subelliptical in side view; highest about onefourth from anterior end; hinge margin nearly straight, 

about seven-tenths of shell length; ventral margin sinuous, concave medially, converging slightly toward 

dorsum posteriorly; anterior margin broadly rounded, 

somewhat produced ventrally; posterior margin more 

narrowly rounded, extended medially, concave above. 

Valves approximately equal in size and of moderate 

convexity; greatest thickness in posterior third.

Free margins with a narrow rim, except in midventral 

portion; a narrow groove, deepest anteriorly, bounds 

rim on its inner side. Midportion of valves slightly 

constricted. Surface within marginal grooves coarsely 

pitted in a reticulate pattern; terminally, pits somewhat 

smaller than medially.

Length of a figured specimen 0.51 mm., height 0.22 

mm., thickness 0.17 mm.

Remarks: The present example is somewhat more 

nearly equal-ended and less concave ventrally than that 

figured by Stephenson, but otherwise it fits his description.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 130 feet, middle Eocene, U.S.N.M. 560703. 

Described from the Weches formation, Claiborne group, 

at Smithville, Tex. (Stephenson, 1946, p. 311).

Cytheromorpha? sp. 

Plate 7, figure 26

Shell subquadrate in side view; highest about onefourth from anterior end; hinge margin nearly straight, 

about five-eighths of shell length; ventral margin 

slightly concave in midportion, converging toward dorsum posteriorly, anterior margin broadly rounded, 

somewhat extended ventrally, truncate dorsally; posterior margin more narrowly rounded, slightly extended 

medially. Left valve slightly larger than the right. 

Convexity moderate, with greatest thickness in midportion.
50 OSTRACODA FROM WELLS IN NORTH CAROLINA

Free margins have smooth rims. Surface coarsely 

pitted. A small node lies beneath anterocardinal angle 

and eye tubercle; two elongate longitudinal swellings 

occur dorsally a little behind middle of shell and ventrally at midlength; a broad depression lies in postventral area; a low subvertical ridge is present ventrad of 

postcardinal angle. Internal features not observed.

Length of figured specimen 0.42 mm., height 0.20 mm., 

thickness 0.15 mm.

Remarks: The general shape of this form allies it 

with CytJieromorpha Hirschmann, but in shape and 

ornamentation it resembles Limnocythere Brady, a 

fresh-water genus. Probably it represents a new species but, as only one specimen was found and the internal features are unknown, the form is not named.

Occurrence: Naval Auxiliary Air Station well, 

Washington, N. C., 130 feet, middle Eocene, U.S.N.M. 

560708.

Genus CYTHERURA Sars, 1865

Cytherura elongata Edwards

Plate 7, figures 24, 25

Cytherura elongata Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 527, pi. 88, figs. 21-25.

The present examples were compared with the types 

and found to be conspecific. The species apparently is 

a guide fossil for late Miocene age in this region, as it 

has not been found in deposits older than the Duplin 

marl. C. wardensis Howe and Brown, originally described from the Choctawhatchee formation of Florida, 

also occurs in the Duplin marl, together with C. reticulata Edwards and C. forulata Edwards. C. wardensis 

has a shorter hinge than C. elongata, more evenly reticulate surface, and no anterior submarginal ridges. C. 

reticulata has a shorter hinge than the present species, is 

more evenly reticulate, has a more uniformly convex surface and a more medially located posterior caudal extension. C. forulata has a more convex dorsum and 

more conspicuous longitudinal surface ridges.

Occurrence: Edenton Naval Air Base well no. 1, 

Chowan County, N. C., U.S.N.M. 560707, 45 feet; Esso 

Standard Oil Company Hatteras Light well no. 1, 220- 

230 feet, upper Miocene, U.S.N.M. 560757; Duplin marl 

near Lumberton, N. C.

Cytherura sp. aff. C. washburni Stephenson

Plate 7, figure 27

Shell subelliptical-acuminate in side view; dorsal 

margin gently convex, straight in midportion; ventral 

margin nearly straight to slightly concave; anterior 

margin broadly rounded; posterior margin greatly extended with well developed caudal process at midheight. Valves approximately equal in size, strongly 

convex; greatest thickness midventral.

Surface ornamentation consists of a midventral 

alaform ridge, highest posteriorly and merging with 

general surface of shell in anterior third; crest of ridge 

bears two narrow grooves. Flattened ventrum ornamented by several longitudinal grooves and intervening 

narrow ridges. Kemainder of the probably abraded 

surface weakly ornamented by inconspicuous pits and 

short ridges. Margins of each valve bear narrow low 

ridges. Internal features not observed.

Length of the single specimen at hand 0.42 mm., 

height 0.20 mm., thickness 0.20 mm.

Remarks: This species probably belongs in the alate 

group of Cytherura represented in the Oligocene by 

G. byramensis Howe and Law (1936, p. 69), C. wailesi 

Howe and Law (1936, p. 71), C. sylvernica Howe and 

Law (1936, p. 70), and in the Eocene by C. washburni 

Stephenson (1946, p. 317). It is less conspicuously 

pitted than C. fiyramensis and bears more abundant 

small ornamental features than C. washburni to which, 

perhaps, it is most closely related.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 135 feet, middle Eocene, U.S.N.M. 560709 ; 

species described from the Weches formation at Smithville, Tex.

Cytherura wardensis Howe and Brown

Cytherura wardensis Howe and Brown, Howe and others, 1935, 

Florida Dept Conserv., Geol. Bull. 13, p. 36, pi. 1, figs. 23, 

27, pi. 4, fig. 19.

Occurrence: Upper Miocene, Esso Standard Oil Co., 

Hatteras Light well no. 1, 160-170 feet, U.S.N.M. 

560717; and in the middle Miocene, Edenton Naval Air 

Base well no. 4, 88 feet, U.S.N.M. 560718, and the Cape 

Lookout well, 75-100 feet, U.S.N.M. 560719. Described 

from the Area zone of the Choctawhatchee formation of 

Florida.

Cytherura forulata Edwards

Cytherura forulata Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 526, pi. 88, figs. 21-25.

Occurrence: One specimen in Pleistocene sand, Esso 

Standard Oil Co. Hatteras Light well no. 1, 60-70 feet, 

U.S.N.M. 560720. Described from the Duplin marl, 

upper Miocene, near Lumberton, N. C.

Cytherura reticulata Edwards

Cytherura reticulata Edwards, 1944, Jour. Paleontology, vol. 18, 

p. 526, pi. 88, figs. 13-16.

Occurrence: Upper Miocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, 460-470 feet, U.S.N.M.
CENOZOIC OSTRACODA 51

560721. Described from the Duplin marl, near Lumberton, N. C.

Genus MONOCERATINA Both, 1928

Monoceratina cf. M. harrisi Stephenson

Plate 7, figure 23

Monoceratina harrisi Stephenson, 1946, Jour. Paleontology, vol. 

20, p. 313, pi. 43, fig. 14.

Shell subquadrate in side view; dorsal margin 

slightly convex, about four-fifths of shell length; ventral 

margin slightly convex, curving gently into posterior 

margin and much more sharply into anterior margin; 

anterior margin strongly produced above, subtruncate 

below. Valves nearly equal in size, the left slightly 

larger.

Free marginal areas of each valve compressed and 

separated from inflated median portion by a rather 

discontinuous submarginal groove. Medially and 

slightly above midheight is an oval depression. Postventral surface strongly inflated, forming a conspicuous 

subalaform elevation. Most of surface coarsely and 

deeply pitted. Internal features not observed.

Length of figured specimen, a somewhat damaged 

shell, 0.57 mm., height 0.29 mm., thickness 0.23 mm.

Remarks: The specimen closely resembles M. harrisi 

from the Weches formation, but the latter has a less distinct compressed marginal border. M. musei Stephenson, also from the Weches, is more sparsely punctate 

and has a Z-shaped median depression, but otherwise 

resembles the present form.

Occurrence: Naval Auxiliary Air Station well, Washington, N. C., 90 feet, middle Eocene, U.S.N.M. 560706. 

Described from the Weches, middle Eocene, from 

Smithville, Tex.

Genus PARACYTHERIDEA Miiller, 1894

A readily available generic description was provided 

by Edwards (1944, pp. 511-512; on page 512, seventh 

line, fourth word, read "left" instead of "right"). Van 

den Bold (1946, p. 26) also discussed Paracytheridea 

and stated its range to be Cretaceous to Recent, but 

placed Mooreina Harlton from the lower Pennsylvanian 

Johns Valley shale in synonymy.

Paracytheridea is close to Perissocytheridea Stephenson (1938), but in the latter alae are lacking and the 

line of concrescence does not coincide terminally with 

the inner margin. Hutsonia (Swain, 1946) from the 

upper Jurassic is similar to Perissocytheridea in general form and hingement but is typically bisulcate. 

Hutsonia may be close to the ancestral stock of the other 

two genera.

Paracytheridea nodosa (Ulrich and Bassler) 

Plate 3, figures 19-22

CytJieropteron nodosum Ulrich and Bassler, 1904, Maryland

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

Paracytheridea nodosa (Ulrich and Bassler), Howe and others,

1935, Florida Dept. Conserv., Geol. Bull. 13, p. 37, pi. 3,

fig. 7. 

"iParacytheridea altila Edwards, 1944, Jour. Paleontology, vol.

18, p. 512, pi. 85, figs. 20, 21.

The external characters of the species were described 

by Ulrich and Bassler. Internal features observed in 

the present material are as follows:

Hinge of right valve consists of an anterior elongate, 

low, crenulate tooth. Hinge of left valve comprises 

an anterior shallow crenulate socket, a narrow interterminal crenulate bar, and a posterior, shallow crenulate socket. Inner lamellae not well defined; inner 

margin and line of concrescence coincide throughout. 

Muscle scar a submedian vertical row of four spots, with 

possibly some anterior spots that were not observed 

clearly. Radial canals few and widely spaced.

Length of figured specimen (pi. 3, fig. 21) 0.66 mm., 

height 0.29 mm.

Occurrence: Edenton Naval Air Base well no. 1, 

Chowan County, N. C., at 55 feet, middle Miocene, 

U.S.N.M. 560644. Described from the Chesapeake 

group (undifferentiated) at James Eiver, Va. (Ulrich 

and Bassler, 1904, p. 130); occurs also in the Choctawhatchee formation at Red Bay, Walton County, Fla. 

(Howe and others, 1936, p. 37), and in the Miocene at 

several localities in Cuba and Guatemala (van den Bold, 

1946, p. 86). P. altila Edwards (1944, p. 512) from 

the Duplin marl of North Carolina may have been based 

on immature molts of P. nodosa.

Paracytheridea? wetherellii (Jones) 

Plate 7, figures 2-4

Cyfhere wetherellii Jones, 1854, Quart. Jour. Geol. Soc., London, 

vol. 10, p. 161, pi. 3, fig. 9; Jones 1856, Tertiary Bntomostraca of England, p. 27, pi. 4, fig. 15, pi. 6, figs. 16a-d.

Shell subtrapezoidal in lateral view; greatest height 

submedian; dorsal margin nearly straight, about twofifths of shell length with broadly obtuse cardinal 

angles; ventral margin gently convex; anterior margin 

narrowly rounded below, truncate above; posterior margin subacuminate below, truncate above. In posterior 

four-fifths ventral surface moderately alate, overhanging valve margin. Entire surface coarsely but not uniformly reticulate. Depressed areas between reticulating ridges finely papillate. Left valve overlaps right 

along free margins.
52 OSTRACODA FROM WELLS IN NORTH CAROLINA

Hinge of left valve consists of terminal oblique, 

elongate, crenulate sockets separated by a narrow, very 

finely crenulate ridge. Hinge of right valve the antithesis of the left. Inner lamella broadest anteriorly; 

line of concrescence and inner margin nearly coinciding. 

Muscle scar and other internal features obscured by 

matrix.

Length of a figured left valve 0.56 mm., height 0.31 

mm.

Remarks: The general outline, ventral alation, and 

hingement of the species resembles features of Paracytheridea Miiller, but the shell is not compressed posteriorly as are more typical members of the genus. The 

present specimens seem identical with P.\ wetherellii 

(Jones) from the middle Eocene.

Occurrence: Esso Standard Co. Hatteras Light well 

no. 1, 320-340 feet, U.S.N.M. 560691; North Carolina 

Esso no. 2, 340-350 feet, middle Miocene, U.S.N.M. 

560692. Described from the middle Eocene, Isle of 

Wight.

Paraeytheridea cf. P. rugosa Edwards

Paracytheridea rugosa Edwards, 1944, Jour. Paleontology, vol. 

18, p. 513, pi. 85, fig. 24.

A single right valve that probably belongs to this 

species was obtained. The hinge consists of an anterior 

crenulate dental area, not noticeably elevated, formed 

of the edge of the valve at its cardinal bend; an interterminal shallow serrate groove; and a posterior small 

perhaps crenulate tooth.

Occurrence: Upper Miocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, 160-170 feet, U.S.N.M. 

560722. Described from the Duplin marl, Lumberton, 

N.C.

Genus Pellucistoma Coryell and Fields, 1937 

Pellueistoma cf. P. magniventra Edwards

Pellticistoma mayniventra Edwards, 1944, Jour. Paleontology, 

vol. 18, p. 528, pi. 88, figs. 33-35.

Occurrence: An imperfect specimen of this species 

was obtained from the upper Miocene, North Carolina 

Esso well no. 2, 130-140 feet, U.S.N.M. 560723. The 

species was described from the Duplin marl near Lumberton, N. C.

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CENOZOIC OSTRACODA 53

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INDEX

Abstract—____----------------------.__________________________----____-.- 1

icuticythereislaevissima....... ...__....................._-------_ 12 (tab.), 42

laevissima punctata—-........ ..__.______.__.______ 12 (tab.), $

multipunctata___._......_....____..___.___,_...___ 12 (tab.), 15,42

alata, Brachycythere- ____-_________--.______________...._______ 44

alexanderi, Cytheretta—_________.....__....._____ 12 (tab.), 46, 47, pi. 6

altila, Paracytheridea-... ____-___-_-_-,__.-_.....__........_____. 51

americana, Cythereis cornuta...-...-..........______...._________ 41

Cythereis (Pterygocythereis)-.--- ...............______.__________ 41

Pterygocythereis cornuta--.-... ....__........._........-.--._ 13 (tab.), 4!

angulata, Cythere.----- —.__-..._..-....-.-.-...___...-.-----..-.__.. 29

Cythereis........——...................-_______.__._______ 29

Hemicythere.l_______._.___.......__..__...._...__-____ 29

Trachyleberis--———------------.--------------------. 14 (tab.), 09, pi. 3

Anticythereis reticulata....... _._.____._._._.___._....._......__ 40

aquia, Haplocytheridea veatchi. ._-....._.......____________..____ 20,21

Trachyleberis communis.----------.---...................-... 13 (tab.), SI, pi. 4

Area zone.- ———————— „.--.——-..-...______-.._.__.--_----_-__-—— 46

ashermani, Cytherideis.... __.................._..-....-...-__ 13 (tab.), 19, 42

(Ashtarotha) concentrica, Astarle_.----..........._....___-__--------- 8

Astarte (Ashtarotheca) concentrica-.-----,- __..................__..._ 8

Asterigerina........—.....__...... —..._.......—.________._.... 8

austinensis, Cythereis.---.--------------... _______-_---.-.__--_.--.-.____. 33,37

B

Bairdiaforfiflcata.---— ......................................... 12 (tab.), 16, pi. 1

laeticula...—.......^'............................................ 12 (tab.), 17

subdettoidea—----—;.---- — — ------—------ — — --........_.. 16

sp._.„————.*.__...-.-.—..--...-...-...___-—.-—.. 12 (tab.;, 16

Bairdiidae-.-._— — ...^.................................^................ 16

Bairdoppilata dellcatula..--.--.--—-............................ 12 (tab.), 17, pi. 1

Basslerella miocenica.......................................................... 47

bassleri, Cythereis.....—........ ._.______...._____.__._____ 34

Cytheretta—..—— — -- — --——-—-- — -——--——-. 12 (tab.), 46 

Trachyleberis......—.i"______________._______ 13 (tab.), 54, pi. 5

bassleri lata, Cythereis......................................................... 34

bassleri reticulolira, Cythereis-..-..........^............... ..__..-..___ 34

Trachyleberis.............................................................. 35

Basslerites giganticus........__.___....__.__________ 12 (tab.), 15, 47

miocenicus.-....................... _______--___.___. 12 (tab.), 47, pi. 7

bernardi, Brachycythere........................... ..._.__...._..___... 44

betzi, Brachycythere.--- ____._-----------_....____. _.._.__ 41,44

bicornis, Cythereis............................................................. 36

Brachycythere alata-----...... ...- —— ———-----------_....___..__... 44

bernardi.......--.-.-......-.-.-.—.....___...._________. 44

betzi....—............................................................... 41,44

hadleyi................................................... 6, 12 (tab.), 44, pi. 7

interrasilis.------...-... _.__-. ——..._.___....__...___.___ 45

jessupensis.......................—...._—...——__—— 12 (tab.), 45, pi. 7

martini....................................................... 12 (tab.), 44, Pi- 6

marylandica.... ——......——.. —._..........______ 12 (tab.), 44, pi. 7

nanafaliana... ....---__...____________._________ 44

watervalleyensis- — ---.............................______________ 44

SP----.__--- ——— —— ___.- —— ----..--.____.....________________ 45

broussardi, Clithrocytheridea............_____..__._. 12 (tab.), 15, 84, 25

Buntonia garretti....- _—------- — -.--..-_-.--.---.---..._. 12 (tab.), 59, pis. 3, 4

howei........................................................ 12 (tab.), 58, pi. 2

lacunosa..........—......................................... 12 (tab.), 59, pi. 7

meguirH................................................... 12 (tab.), 39, 40, pi. 4

okeechobiensis.--.............—. .______......____________ 39,40

planUxailw.......—......................................... 12 (tab.), 59, pi, 3

sp............—...........—........................................... 17,38

burnsi, Cytheretta....—...................................................... 46

byramensis, Cytherura......................................................... 50

Bythocgpris parilis...................................................... 12 (tab.), J7

wicomicoensis................................................. 12 (tab.), 17, pi. 1

0

caldwellensis, Clithrocytheridea ---------_____________. 12 (tab.), 84, pi. 2

Cytheridea ......—.—.—.—........................................... 24

cancellata, Cythere................. .————_____...—_._————__ 44

Cancris cubensis........... ...- —————— ————— ——— ——— ———————— 8

Cauditesjacksonvillensis-......—.-............................... 12( tab.), 42, pi. 5

sellardsi....---—————....———————————...—.—— ———————— 42

Oenozoic section, Hatteras Light Well no. 1__________________... 8-11 

chickasawhayensis, Eucythere....-......—..............—......... 13 (tab.), 18, pi. 1

choctawhatchiensis, Cytheretta karlana.................... .....--________ 46

claibornensis, Loxoconcha ....——.....................____ 13 (tab.), 86, pi. 2

Cythereis.................................................................. 34

clarkana, Cythere—..—...................................................... 43

Leguminocythereis......._________-_________ 13 (tab.), 40, 45, 44, pi. 6

Trachyleberis................................................—..—....... 35

Clithrocytheridea..-—..—...——.................................—... 12 (tab.)

broussardi......................................._______ 12 (tab.), 15, 84, 25

caldwellensis---........ ——— .................——........ 12 (tab.), 84, pi. 2

rugata......... —————————— — —— ----- — ------ ———.-————— 24

smtihvillensis—................................................ 12 (tab.), 05, pi. 2

virginica................................—........._._ 12 (tab.), 84, 25, pi. 2

sp————————--------——---..-.--.--------..--———..-—-. 84, pi. 2

concentrica, Astarte (Ashtarotha)............ __________.....__———————— 8

confragosa, Hemicythere........... ...__.________._____ 13 (tab.), 42, pi. 6

conradi, Hemicythere.................................... ..._ 13 (tab.), 48,45, pi. 6

cornuta, Pterygocythereis.—....—....—..............—..................... 41

Cythereis..... ———— ------ ——.. ————— — ———-—.———————— 41

Pterygocythereis................ ......-------—. ——— —— ——— - 13 (tab.), 41

corrugata, Loxoconcha......................................................... 27

Crassindla dupliniana........................................................ 8

crassipinnatum, Cytheropteron................................................. 49

creolensis, Loxoconcha.........................................—— 13 (tab.), 87, pi. 2

Cretaceous strata, well no. 2 ———— ——.... ——— --------- — —— ———— 12

cubensis, Cancris...................————___——----_ — ———— ——— 8

curta, Cytheromorpha..................................--.-.__. 13 (tab.), 49, pi. 7

Cushman, J. A., cited.—________._______...__....———.— 8

Cypridae___——————..—.„.——_........——...——.————— 16

Cythere angulata-...... .——.......—————.....—.——...————————— 29

cancellata....................——......... —————————————————— 44

clarkana.................................................................. 43

evax............-............................................-.-----.......• 28

oblongula...................................................---........... 28

exanthemata-................................................—............ 37

marylandica...................................................--...... 37

inequivatvis....—.............................................-............ 46

lacunosa.................................................................. 39

martini................................................................... 29

marylandica—...............—————————————————————————— 44

ovalis..-...------------.--------—--—---------—-—----................ 44

planibasilis.....—........................................................ 39

porcella......................................———————————————— 45

rugipiinctata.............................................................. 38

oaughani.......................................———...——— ——...— 37

wetherellii-............................................................... 51

Cythereis angulata...-..—.................................................... 29

austinensis....--- -.— --._-..---.-.- —— - ———.- ——————. —— —— -— 33,37

bassleri-........ —— ----------——.—...———i..................... 34

lata................................................................... 34

reticulolira............................................................ 34

bicornis................................................................... 36

claibornensis.............................................................. 34

cornuta americana....................................................—.. 41

davidwhitei................................................................ 33

evax....................................................................... 28

evergreenica....................................................——...... 46

exanthemata.......—..................................................... 37

garretti.................................................................... 39,40

hazzardi.................................................................. 36

55
56 INDEX

Cythereis—Continued

hilgardi .................................................................. 31,32

mcguirti.................................................................. 40,44

macropora..............................................................-. 30

martini........... ....................................................... 29

midwayensis..... ........................................................ 33

mundorffi................................................................. 36

orelliana.................................................................. 35

paraustinensis ............................................................ 37

pellucinoda............................................................... 34

pidgeoni-................................................................. 36

plusculmenis....................___________________..--.-- 34

guinquespinosa—.......................................................... 33

reesidd—................................................................. 30

rugipunctata............................................... ________ 38

rukasi.................................................................... 30

siegristae........................ .________-____________ 31

smithvillensis.............................................................. 35

stenzeli.-—....—........................................................ 32

theeli...-—--............................................................. 30

triplistriata—.-----....................................................... 37

vaughani.................................................................. 37

worthensis................................................................ 33

Cythereis (Pterygocythereis) americana......................................... 41

Cytherella hannai................................................. 12 (tab.), 14, pi. 1

marlboroensis....................................................... 12 (tab.), 14

sp........................................................... 12 (tab.), 14, P. 15

Cytherelloidea howei............................................... 12 (tab.), IS, pi. 1

sp————— ———————————————.————— 16

Cytheretta alexanderi....—.................................... 12 (tab.), 46, 4?, pi. 6

bassleri............................................................. 12 (tab.), 46

burnsi......__-_________.-___--..___-_________ 46

darenslt...................................................... 12 (tab.), 46, pi. 6

howei..................................................................... 7

inaequivalvis........................................................ 12 (tab.), 46

karlana....................................................... 12 (tab.), 46, pi. 6

choctawhatchiensis..................................................... 46

plebeia.................................................... 12 (tab.), 46, 46, pi. 6

porcetta....................................................... 12 (tab.), 45, pi. 4

reticulata..... ............................................................ 46

Cytheridae———----——--———--—--_--- — ----------._--__.. —.._. 17

Cytheridea caldwellensts....................................................... 24

habropaptllosa............................................-_________ 21

hopkinsi.................................................................. 23

montgomery ensis.--....................................................... 20

mulleri. ————————......_..___-------_------_..__———— 21

pidgeoni.................................................................. 36

subovata.................................................................. 22

veatchi....—.............................................................. 21

sp..............—................................................. 12(tab.),;0

Cytherideis ashermani................................................ 13 (tab.),i9,4?

longula.-----....................................................... 13 (tab.), 19

rugipustulosa....................................................... 13 (tab.), SO

semidrcularis............................................................. 19

Cytheromorpha curta.............................................. 13 (tab.), 49, pi. 7

eocenica............_____.______._--.._______ 13 (tab.), 49, pi. 7

rosefteldensis.............................................................. 49

warneri. .............-------_.____..--._________ 13 (tab.), 49, pi. 7

okaloosaensis.............................................................. 49

sp———————— —————————————— 13 (tab.), 49, pi. 7

Cytheropteron................................................................. 6

crassipinnatum........................................................... 49

montgomeryensis.......................................................... 48

nodosum.................................................................. 51

subreticulatum................................................ 13 (tab.), 48, pi. 7

variosum...................................................... 13 (tab.),48,pi. 7

sp. a— --------------------------------.-----------.-----.._.-. 13 (tab.), 48, pi. 7

sp. b.————.. ————. — — . — — — —— — . — — „-- 13 (tab ),49

Cytherura byramensis......................................................... 50

elongata—...................................____........ 13 (tab.), 50, pi. 7

forulata—..—..................................................... 13 (tab ),BO

reticulata......................................................__ 13 (tab.), BO

sylvernka................................................................. 50

tvailesi.................................................................... 50

wardensls—————_-_.________._____________ 13 (tab.), 50 

washburni......................................................... 13 (tab.), SO

D

darensis, Cytheretta................................................ 12 (tab.), 46, pi. 6

daeidwhitei, Cythereis.......................................................... 33

Trachyleberis............................................. 6,13 (tab.), S3, pis. 4,5

delicatula, Bairdoppilata.......................................... 12 (tab.), 17, pi. 1

depressa, Xestoleberis.......................................................... 18

dibollensis, Textularia......................................................... 8

dumblei, Xestoleberis.—.....................——————————————————— 18

dupliniana, Crassinella........................................................ 8

E

edentonensis, Loxoconcha.......................................... 13 (tab.),«5,pl. 2

elongata, Cytherura.........................................—.... 13 (tab.), 50, pi. 7

Eocene series. ___.___________————————————————————— 6 

well no. 1——--------_.__...... ——————— ———— ———————— 10

well no. 1................................................................. 11-12

eocenica, Cytheromorpha........................................... 13 (tab.), 49, pi. 7

Eocytheropteron................................................... 13 (tab.), 47, pi. 7

Eucythere chickasawhayensis....................................... 13 (tab.), 18, pi. 1

sp..————————————————————- 13 (tab.), 15, 19

evax, Cythere.................................................................. 28

Cythereis.................................................................. 28

Trachyleberis................................................ 7,14 (tab.), «8, pi. 3

evax oblongula, Cythere......................................................... 28

evax oblongus, Trachyleberis.................................................... 28

eeergreenica, Cythereis......................................................... 46

exanthemata, Cythere.......................................................... 37

Cythereis.................................................................. 37

Trachvleberis............................................ 14 (tab.), 33,36,ST.pl. 6

exanthemata gomillionensis, Trachyleberis..-------............................. 37

exanthemata marylandica, Cythere............................................. 37

F

Favetta mesacostalis..................................................... 13 (tab.),4^

rugipunctata............................—................................ 17,38

forbesiana, Pterygocythereis................................................... 41

fortificata, Bairdia................................................. 12 (tab.), 16, pi. 1

forulata, Cytherura...................................................... 13 (tab.),50

ranquesi, Paracypris..<............................................ 13 (tab.), 16, pi. 1

Gardner, Julia, quoted-.-._.__..__——————————————————-- 8 

garretti, Buntonia............................................. 12 (tab.), S9, pis. 3,4

Cythereis........—...—..—.............................................. 39,40

giganteus, Basslerites... __________-------------_------- 12 (tab.), 15, 47

Globigerina................................................................... 6,9

Olyptobairdia................................................................. 16

gomillionensis, Trachyleberis exanthemata.--------..............'............... 37

goochi, Haplocytheridea-.-..............--------__.——-.___----- 13 (tab.)

habropapillosa, Cytheridea..................................................... 21

Haplocytheridea.......................................------- — ——— —— 21

hadleyi, Brachycythere.......................................... 6,12 (tab.), 44, pi. 7

Haplocythereidea....... ____----------__..._--..___.___----- 24

hammond'ensis, Haplocytheridea.-................................. 13 (tab.), 88, pi. 1

Haplocytheridea goochi..................................................... 13 (tab.)

habropapillosa........—............... .................................. 21

hadleyi.................................................................... 24

hammondensis—-............................................. 13 (tab.), 88, pi. 1

harrisi.—-............................................ ................ 25

hopkinsi............................ ......................... 13 (tab.), 8S, pi. 2

israelskyi................................................... 7, 13 (tab.), SO, pi. 1

lisbonensis................................................................ 20,21

montgomeryensis..................................... 6,13 (tab.), HO, 37, pis. 1, 2

nowotnyi........................ ___........—..-._--------— 13 (tab.), SS

subovata....... ___-.______—------—--------_ 13 (tab.), 88, pi. 1

t ex ana........... —————————————————————————. - ————— 22

veatchi.................................................... 13 (tab.), 20, SI, pi. 1

aguia................................................................. 20,21

wallacei...................................................... 13 (tab.), SI, pi. 2

harrisi, Haplocytheridea....................................................... 25

Monoceratina................................................. 13 (tab.), SI, pi. 7
INDEX 57

hazzardi, Cythereis...,........................................................ 36

Hernia/there....—.——__.___________________________ 17

angulattt-....................—........................................... 29

confragosa.................................................... 13 (tab.), 4*, pi. 6

conrodi————————.————————__———____ 13 (tab.), 49, 4$, pi. 6

hilgardi, Cythereis.........................................,................... 31,32

Trachyleberis....................................... 13 (tab.), SI, 33,37, pis. 4,5

Aopfemsi, Cytheridea........................................................... 23

Haplocytheridea............................................... 13 (tab.), 85, pi. 2

Leptocytheridea............................................................ 23

howei, Buntonia-................................................ 12 (tab.), 58, pi. 2

Cytherella.................................................... 12 (tab.), 14, pi. 1

Cytherelloidea.—............................................. 12 (tab.), 15, pi. 1

Cytheretta...........................................•..................... 7

Pyricythereis——.......................................................... 38

Hutsonia..................................................................... 51

ineguiealvit, Cytheretta.................................................. 12 (tab.), 46

inequivalvis, Cythere........................................................... 46

interrasilis, Brachycythere...................................................... 45

Introduction_._._____________________________ l 

israelskyi, Haplocytheridea—................................... 7, 13 (tab.), SO, pi. 1

jacksonvQlensis, Caudites.......................................... 12 (tab.), 4$, pi. 5

jessupensis, Brachycythere......................................... 12 (tab.), 45, pi. 7

karlana, Cytheretta....._____._..______________ 12 (tab.), 46, pi. 6 

karlana choctawhatchieensis, Cytheretta......................................... 46

lota, Cythereit bassleri......................................................... 34

lacunosa, Buntonia............................................... 12 (tab.), 89, pi. 7

Cythere................................................................... 39

laevicula, Bairdia...........................................__........ 12 (tab.), 17

laevissima, Aeuticythereis. ....................................:___.. 12 (tab.), 42

punctata, Aeuticythereis............................................ 12 (tab.), 49

Leguminocythereis clarkana............................. 13 (tab.), 39, 40, 45,44, pi. 6

scarabaeut.......................—......................... 6,13 (tab.), 45, pi. 6

whitei—.................................................. 13 (tab.), 48, pis. 3, 4

Leptocytheridea hopkinsi..................... ................................. 23

linospinosa, Trachyleberis.-................................................... 36

lisbonensis, Haplocytheridea................................................... 20,21

Localities_______________.________________. 2 (map), 3-5 

longissima, Xestoleberis.........................................— 14 (tab.), 18, pi. 1

longula, Cytherideis..................................................... 13 (tab.), 19

Loxoconcha claibornensis......—————.—.———........._. 13 (tab.), 86, pi. 2

creolensis.-.-.-............................................... 13 (tab.),«7, pi. 2

corrugata.....__________._—._____.__...—...——.-.._. 27

edentonensis.................................................. 13 (tab.), 96, pi. 2

mcbeanensis........................................................... 13 (tab.)

postdecliva................................................................ 44

reticularis................. ........................................ 13 (tab.), 96

subrhomboidea...—...................................... 13 (tab.), 95, 26, pi. 2

surrealu—-.................................................. 13 (tab.), 97, pi. 2

M

mcbeanensis, Loxoconcha................................................... 13 (tab.)

mcguirti, Buntonia.......-...........-...-...----............. 12 (tab.), 39, 40, pi. 4

Cythereis.................................................................. 40,44

macropora, Cythereis......................................................-... 30

magniventra, Pellucistoma.............................................. 13 (tab.), 69

marginoreticulata, Trachyleberis................................................ 32

Marginulina idiomorpha zone...__.-..—....._....—.——.————— 22

marlboroensis, Cytheretta...........................................—... 12 (tab.), 14

martini, Brachycythere............................................ 12 (tab.), 44, pi. 6

Cythere................................................................... 29

Cythereis...............................................______..__ 29

Trachyleberis.......................--.-.-.-..__._...._. 14 (tab.), 99, pi. 3

marylandica, Brachycythere.............. — ....................... 12 (tab.), 44, Pi- 7

Cythere................................................................... 44

exanthemata........................................................... 37

mesacostalis, Favella.................................................... 13 (tab.), 41

micula, Trachyleberis..........--.----.--.....-.-.................... 14 (tab.), 15, 99

midwayenais, Cythereis____....—_.._———————————————-. 33

Miocene series____ 

well no. 1..........

well no. 2—.......

miocenica, Bassalerella.

................................................. 7

———————_——_———._——————_-. 9

_____________________________ 11 

_________________ . ___________ 47 

miocenicus, Basslerites ...... . ..................................... 12 (tab.), 47, pi. 7

Monoceratina harnsi... ......... ........................... ....... 13 (tab.), 61, pi. 7

musei ............... .... ... .... ...... .... ... .............. ............ .... 51

montgomeryensis, Cytheridea ..... ... ... ..... . ____ __ _________ _ 20

Cytheropteron .... ............ _______________________ 48

Haplocytheridea....................................... 13 (tab.), 80, 37, pis. 1, 2

Mooreina.... _____ __ ... _ _______________________ 51

mulleri, Cytheridea... ..... .........———— ——...... ........................ 21

multipunctata, Aeuticythereis... ...................................... 12 (tab.), 15, 49

mundorffi, Cythereis.. ... ... ... ... ________ .. __ .. __ ____ ___ 36

Trachyleberis....... ........................ ............ 13 (tab.), '36, 37, pis. 5, 6

musei, Monoceratina ......... . ___ ....... _ .. ____ .. _________ 51

N

nanafaliana, Brachycythere.............. ... . .... . ...... ....................... 44

nodosa, Paracytheridea _____ . _________________ 13 (tab.), 51, pi. 3 

nodosum, Cytheropteron- ... _ __ --- __ ------- _ ____ _ __ _______ 51

nowotnyi, Haplocytheridea.-... ... . ____ .. __ - _ .. _ — .. —

O 

oblongula, Cythere evax.. ........ ..----..._. _ — .. — _ — . —— __ . ____ 28

oblongus, Trachyleberis evax...... ____ — _ — -.-..-. —— .. — _______ 28

okeeehobiensis, Buntonia ....... .——..-——. _ . ________________ 39,40

Oligocene series. _____ _ __ .... _ ... _ --.. — _ ... __________ 6

well no. 2— ------ _ .__._-_..__---_---- _ .-.--.. __ .-._-.. __ ... _ _ 11

Oligocythereis . .....— ...... .—....— ————..—— . ______________ 41

orelliana, Cylhereis... ...... ... .... ... ... ... .... ....... ... ... .................. 35

Trachyleberis .... .-_----__---.-------.---------- _ —----___---.__-__—_ _ 33

okaloosaensis, Cytheromorpha warneri..... ... .... ... . ... .... ... ... ... ... ___ 49

ovalis, Cythere— .......... . ... ..... ... . ——— ... ——————————— __ ... 44

Paleocene series..———————————————————————————————;.. 5 

well 110. 2—_....——.—————-—————————————————————— 12

Paracyprisfranquesi...—.......——....-————————— 13 (tab.), 16, pi. 1

strecca.................—....—————..————.—.......—........ 16

Paracythereis...................................... ...............——————— 40

potomaca...........------------------- ..——.— -.- —— ——— -————— 34,35

Paracytheridea.... ———— — -- ——— --- —————————————— ———— 61

aUila—................................................................... 51

nodosa...............-..——.———...————..————... 13 (tab.), 51, pi. 3

rugosa......... ——— — --____- —. — — — —. — — ——— — 13 (tab.), SIS

wetherettii--.. —............................................. 13 (tab.), 61, pi. 7

paraustinensis, Cythereis.-...............................—................... 37

panlis, Bythocypris——------------—.-.----------------————-- 12 (tab.), 17

pellucinoda, Cythereis————————.————. —— -—————————————— 34 

Trachyleberis——-—.———————————— 13 (tab.), S4, pis. 4,5

Pellucistoma magnieentra—........................................—.. 13 (tab.), 59

Perissocytheridea..........-_.__-- —— —— _-__--.. — — --...—————————— 51

pidgeoni, Cythereis.--....------- — - —— — ------- — - —... —— _ ——— _.—— 36

Cytheridea--.—........ — ————.......———..——.—.——.——... 36

sills, Buntonia..—---.-...--..------.---.-------.-----. 12 (tab.), 59, pi. 3

Cythere. ———.————————— — ———————————— 39

eia, Cytheretta——— -•——————————————— 12 (tab.), 45, 46, pi. 6

Pleistocene series. ——————————— --——————————————————— 7 

well no. 1_-—— — ------- — —— -- ——. —— -- ———— —— — ——— -. 8

Pliocene series—————————————- ————— - ——— -——————————— 7 

well no. 1. _._-_—--—--_------------------------------—---------—------- 9

well no. 2__ ——————————————————— - — -———————————— 11 

plusculmenis, Cythereis..—................................—-................ 34

IVac%Ze6eris—--------------------------------------------------—---- 35

porcella, Cythere.... ————— - — ---------- — ------ —— __ — __-————— 45

Cytheretta.... —————————— ——————— — — 12 (tab.), 46, pi. 4

postdecliva, Loxoconcha...................------ ...------- —— ———————— — 44

potomaca, Paracythereis............... — ..................... —————— —.. 34,35

Protocythere...——————— — ---- —— - ———— - ——— ——— ————— -- 39

Pseudocythereis........——————-———— —.. —————————————— - 40

rrf»CM?a<a---------------------------------------------------------------- 40

Pterygocythereis........ ...---------- —..--. — —. — —— — ————————— 17

americana, Cythereis,--........................ —..... ——— — ——— ---- 41

cornitta. —..............------- — —— —— ----- —— — — -_„-- —— —.-. 41

americana............... „....---- —— -- —— --- — - — -———— 13 (tab.), 41

forbesiana...-............................-........................—.. — .- 41

washingtonensis..............—.............——- ——. — ..-. 13 (tab.), 41, pi. 4
58 INDEX

punctata, Acuticythereis laevissima.. — - _________________ 12 (tab.), 4%

Pyricythereis.--———____-_____-_-_..----______________________ 40

howei--.---...---------- ________________________________________ 38

quinguespinosa, Cythereis _ 33

Recent series.--______-________-___________.__________ 8

well no. l_-----_-----_--__-----__ ^---------------------------------------- 8

reticularis, Loxoconcha___. ______________________________________ 13 (tab.), Z6

reticulata, Anticythereis_--_____________-_. ______________________________ • 40

Cytheretta... ___— _____________________________________________.. 46

Cytherura-—------------------------------------------------ 13 (tab.). 50

Pseuiocyikereis--------------------------------------------------___ _..___ 40

reticulolira, Cythereisbassleri^ _______________________________________ 34

Trachyleberis bassleri--------------------. — . ________________________ 35

reesidei, Cj/_..«ms-------___-___-_________--_-__________________. ____________ 30

Trachyleberis-.---------.---------------------------------------- 14 (tab.), SO, pi. 3

rosefieldensis, Cytheromorpha-. —-------------------- __________._____- 49

ro&etta, Trachyleberis__________________------_-_-______________ 14 (tab.), 28, pi, 3

rugata, C^ithrocytheridea.- _.--_________--_---________________________ 24

rugipustulosa, Cytherideis..__ ----------------------------------- _____ 13 (tab.), 20

rugipunctata, Cythere- _________________________________________ 33

Cythereis--____---------------- -------___________________ 38

Favella.---------------------------------------- ________________ 38

Trachyleberis—.- — - _______________________________ 14 (tab.), 38, pi. 6

rugosa, Paracytheridea——___________---------_----.________________ 13 (tab.), 52

rukasi, Cythereis.- ___------__-----____--______________________ 30

Trachyleberis--------------------------------------- 13 (tab.), SO, 35, 37, pi. 4

scarabaeus, Leguminocythereis- ___________________________ 6,13 (tab.), 48, pi. 6

sellardsi, Caudites----. ___-_--__--___-----------.________________ 42

semidrcularis, Cytherideis.-------------------------------------- _______. 19

siegristae, Cythereis__.-._____._________--.___________________ 31

Trachyleberis_--_-____________--..-____________..._______ 32

smithvillensis, Clithrocytheridea—-------- ___---_---_________ 12 (tab.), 23, pi. 2

Cytheries__ —— ———— -------_-—.—_---_-_---______________ 35

Trachyleberis---...------------------------------------ 13 (tab.), 32, 35, pi. 5

Spangler, W. B., cited____________-_---___________________ 3

Stratigraphy, diagram showing_________________________ 5

summary,..— ———— --------____—________________________ 5-s

stenzdi, Cytheries----- _____________--______________________ 32

Trachyleberis-—---—_.—.__________—„-__--______ 13 (tab.), SS, 37, pis. 4, 5

strecca, Paracypris-- ____--—------__-________________________ 15

subdeltoidea, Bairdia.- ______--___________..__-_.-_____ 16

subovata, Cytheridea.... .---._..______.________________ 22

Haplocytheridea_____.__—_____——___________ 13 (tab.), B2, pi. 1

subreticulatum, Cytheropteron_______,__.____________ 13 (tab.), 48, pi. 7

subrhomboidea, Loxoconcha-- ___________________ 13 (tab.), 25, 26, pi. 2

surreala, Loxoconcha-.....-_-_-____-__._-__-__..-___._ 13 (tab.), 27, pi. 2

sylvernica, Cytherura-..... ___-_-__.________.__________________ 50

T

Tertiary strata, correlation.------__________________._ ______ 4

texana, Haplocytheridea_____ ..____—_.-.____________ 22

theeli, Cythereis---- ___.-._______-_________________ 30

Trachyleberis.... .---__--__.________________________ 9,17,39

angulata—-------------——-.-.. ......................... 14 (tab.), 29, pi. 3

batsleri————————.— — -...-—................... 13 (tab.), S4, pi. 5

reticulolira—————___.__---------________________ 35

claibornensis........_____-______________________ 35

communis aquia,-. ......... ——— __._--.__-___________ 13 (tab.), 31, pi. 4

davidwhitei—.....--_----.. .____.____ — .___:_____.____ 6,13 (tab.), SS, pis. 4, 5

dibollensis..........________-________.._________ 8

Traehyleberis—Continued

epos.—.—————————————————_ 7,14 (tab.), 28, pi. 3

oblongus_______________.—— —————————— ————— 28

exanthemata-..........................-_._______ 14 (tab.), 33, 36, 57, pi. 6

gomillionensis...........................— ——————————————— 37

hilgardi——........................................ 13 (tab.), SI, 33, 37, pis. 4, 5

linospinosa_____.-__-___-.____-..————————————————— 36 

marginoreticulata—...........................—.......................... 32

martini..-...... _.._———___——.—___..__—___——————— 14 (tab.), 29, pi. 3

micula——...................................................... 14 (tab.), 15, 29

mundorffl.... .________________________ 13 (tab.), 56, 37, pis. 5, 6

orelliana.. ————————— ————— ——— —— ———————— _ ——— ——— 33

pellucinoda.....—--.-....---... __—__——____———_. 13 (tab.), S4, pis. 4, 5

pidgeoni--.- ............................................... 13 (tab.), 56, pi. 6

plusculmenis____--._-__--_____...—— —— ——— ------————— 35

reesidei.- _________--_------.--_---------__-----_--_-__-_ 14 (tab.), SO, pi. 3

rosetta—.—......—........................................ 14 (tab.), 28, pi. 3

rugipunctata-....... ___ ————_——------—————————— 14 (tab.), S8, pi. 6

rukasi ....... ...................................... 13 (tab.), SO, 35, 37, pi. 4

siegristae_____________________————————..——.——— 32

smithvillensis——.......................................... 13 (tab.), 32, 55, pi. 5

stenzeli-- — -.....—-----.-----.---------- — ------.. 13 (tab.), S2, 37, pis. 4, 5

triplistriata-—............................................. 14 (tab.), 57, pi. 6

vaughani_____..---__--_-_--------------.-_ —— ——— 14 (tab.), 57, pi. 6

vicksburgensis___———_———._--_.- —. —— -———————————— 35 

weaverL ------------ —— _ — ——— _- — -- ——— ----- ———————— —— 35

Triebelinasp—-----------------------------------------—.... 14 (tab.), 17, pi. 1

triplistriata, Cythereis___________-----——————————————- — - 37

Trachyleberis—.————————————————— 14 (tab.), 57, pi. 6

variosum, Cytheropteron_______________--_------— 13 (tab.), 48, pi. 7

vaughani, Cythere______..—————_-.._—____-—————————————————— 37

Cythereis--...-------------------_-----.-_„-----.---————....——-. 37

Trachyleberis————— —————————————— 14 (tab.), 57, pi. 6

veatchi, Cytheridea____...—————_——-—__-.-——————————————— 21

Haplocytheridea——- ——— — -—---— — ----—— 13 (tab.), 20, 21, pi. 1

veatchi aquia, Haplocytheridea—-. ——-————----- — ---.———————————— 20,21

ventrostriata, Xestoleberis.-—- ______-.---__--- ———— —— 14 (tab.), 18, pi. 4 

s, Trachyleberis------------------------------—————.—-—— 35

—————-.— — — - ———- — — — — ——————-- 18

i, ClUthrocytheridea-—...........——....—............ 12 (tab.), 24, pi. 2

W

wailesi, Cytherura_______-_______-__-------.-_--_.__—— 60

wallacei, Haplocytheridea_________..____________ 13 (tab.), 21, pi. 2 

wardensis, Cytherura-- _________________________ 13 (tab.), 50

warnen, Cytheromorpha,.——.. ___________—.—_—... 13 (tab.), 4fl, pi. 7

warneri okaloosaensis, Cytheromorpha——.-.-_—„. —— ——— —————————— 49 

washburni, Cytherura _--.___ ——— — _--_----_.-_———— —— __———— 13 (tab.), 50

washingtonensis, Pterygocytheris-..-. _.-_._.-,---_---------_-. 13 (tab.), 41, pi. 4

watervalleyensis, Brachycythere—.____.-__,-___---------_------—— 44

weaveri, Trachyleberis............. ——.__-_-___———————..——————— 35

Wells, stratigraphy of....— ————— - —— ----- ———— -_.. ———————— —— 8

wetherellii, Cythere- ___.. —— _.-——_---__--_ — ----_—.————————— 51

Paracytheridea- ____________.__.________ 13 (tab.), 61, pi. 7 

whitei, Leguminocytheris...————__----------——._ — -— 13 (tab.), 45, pis. 3, 4

wicomicoensis, Bythocypris____.-_-_--_-----_-__-_____ 12 (tab.), 17, pi. 1

worthensis, Cythereis__ ————— -__--___-------—-__._——————-——— 33

X

Xestoleberis depressa....——————.—————.__ — ___ — — ———————.. 18

dumblei_______———————-.____.______________—.- 18

longissima. —————————————_ —————.——— 14 (tab.), 18, pi. 1

ventrostriata____________________________ 14 (tab.), 18, pi. 4 

vicksburgensis........——-—_-_—____---------______—— 18

sp.———.__——-1——————— ————— — —— 14 (tab.). 15, 18

o


PLATES 1-7
PLATE 1

Page

FIGURE 1. Cytherella cf. C. hannai Howe and Lea. Exterior of left valve, X 50. Lower Miocene, Esso Standard Oil Co.

Hat teras Light well no. 1, 1,160-1,170 feet. U.S.X.M. 560595____----__-_---_ _________ __ _._.__. ____ ____ 14

2, 3. Cytherelloidea howei Swain. Left side and dorsal views, X 66, of different specimens. Lower Eocene, Naval

Auxiliary Air Station well, Washington, N. C., 195 feet. U.S.X.M. 560596 _____________ ___________ _____ 15

4, 5. Bythocyprist wicomicoensis Swain. Right sides of two shells, X 60. Middle Eocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, core 1,740-1,750 feet, U.S.X.M. 560597 and cutting sample 1,770-1,780 feet. 

U.S.X.M. 560598 _ _________________________________________________________________________ 17

Paracypris cf. P. franquesi Howe and Chambers. Exterior of a left valve, X 55. Lower Eocene, Esso Standard

Oil Co. Hatteras Light well no. 1, 2,720-2,730 feet. U.S.X.M. 560599______ ________________________ 16

Triebelina sp. Exterior of an incomplete right valve, X 85. Lower Miocene, Esso Standard Oil Co Hatteras

Light well no. 1, 1,380-1,390 feet. U.S.X.M. 560600 ________________________ __________________________ 17

Bairdoppilata cf. B. deliratula Jennings. Right sides of two shells, X 50. 8, broken posteriorly, 1, 6, middle Eocene, 

Esso Standard Oil Co. Esso well no. 2, 1,620-1,630 feet, U.S.X.M. 560601. 9, middle Eocene, Esso Standard 

Oil Co. Hatteras Light well no. 1, 2,135-2,145 feet. U.S.X.M. 560602_________________________________. 17

10. Xestoleberis'' cf. A", longissima Schmidt. Right side of a poorly preserved shell, X 85. Lower Eocene, Esso

Standard Oil Co. Hatteras Light well no. 1, 2,390-2,400 feet. U.S.X.M. 560603_________________________ 18

11-13. Eucythere cf. E. chickasaichayensis Howe. Right side and interior of right valve, interior of left valve of a well 

preserved s]>ecimen, X 74, 12 and 13 slightly retouched. Upper Miocene, Esso Standard Oil Co. Hatteras 

Light well no. 1, 700-710 feet. U.S.X.M. 560604 ________________ _________ _________________ 18

14. Bairdia cf. B. fortificata Brady. Right side of a well preserved shell, X 78. Upper Miocene, Edenton Naval

Air Base, no. 1, Chowan Co., N. C., 40 feet. U.S.X.M, 560605.________________________________________ 16

15-17. Haplocytheridea sp. aff. H. israrlski/i Stepheiison. 15, 17 Interior of right and left valves, X 71, of a well preserved 

specimen. 16, Right side of another specimen, X 71. Upper Miocene, Xaval. Auxiliary Air Station well. 

Washington, N. C., 60 feet. U.S.XM. 560606__ _ ___ ______________________________________________ 20

18. Haplocytheridea montgomeri/ensis (Howe and Chambers). Right side of a poorly preserved specimen, X 74.

Middle Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, 1.950-.1.960 feet. U.S.X.M. 560607______ 20

1!)-20. Haplorytheridea cf. //. suborata (Ulrich and Bassler). Right sides of two specimens, X 59. Oligocene or lower

Miocene, Esso Standard Oil Co. Hatteras Light well no. 1, 1,620-1,630 feet. U.S.X.M. 560608, 560609 _____ 22

21. Haplocytheridea sp. aff. //. hammondensis (Swain). Right side, X 93. Middle Eocene, Xaval Auxiliary Air Station well, Washington, N. C., 90 feet. U.S.X.M. 560610_ __________________ __________^________ 22

22. Haplocytheridea reatrhi (Howe and Garretr). Exterior of a poorly preserved left valve, X 50. Middle Eocene,

Esso Standard Oil Co. Hatteras Light no. 1, core 1,740-1,750 feet. U.S.X.M. 560611___________________ 21
GEOLOGICAL SURVEY PROFESSIONAL PAPER 234 PLATE 1

CYTHERELLIDAE, CYPRIDAE, BAIRDIIDAE, CYTHERIDAE
PLATE 2

Page

FIGURES 1-4. Haplocytheridea montgomeryensis (Howe and Chambers) 1, 2, 4, Right sides and ventral view of a male and 

two female shells, all X 65. Middle Eocene, Xaval Auxiliary Air Station well, Washington, N. C., 115 

feet. U.S.X.M. 560612. 3, Right side of a poorly preserved male shell, X 50. Middle Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, core 1,740-1,750 feet. U.S.X.M. 560613-_________________ 20

5. Haplocytheridea? cf. H.? hopkinsi (Howe and Garrett) Exterior of a right valve, X 83, specimen broken.

Lowei Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, 2,840-2,850 feet. U.S.X.M. 560614____ 23 

6-7. Haplocytheridea cf. H. wallacei (Howe and Garrett) Exterior of a left valve, and right side of a complete specimen, X 88. 6, middle Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, core 1,740-1,750 feet. 

U.S.X.M. 560615. 7, lower Eocene, Esso Standard Oil Co. X. C. Esso well no. 2, 1,950-1,960 feet. U.S.N.M. 

560616. ______________________________________________ __________________________ 21

8. Haplocytherideal cf. //. goochi Stephensoii. Right side of a complete specimen, X 90. Middle Eocene, Esso

Standard Oil Co. Hatteras Light no. 1, core 2,176-2,206 feet. U.S.X.M. 560617____________ __ 23

9. Clithrocytheridea cf. C. smithvillensis Stephenson. Right side of an imperfectly preserved specimen, X85. Middle Eocene, Esso Standard Oil Co. X. C. Esso well no. 2, 1,480-1,490 feet. U.S.X.M. 560618________ 23 

10-13. Clithrocytheridea virginica Schmidt, X78. 10, Right side of a female example. 11, Left side of a male example. 

12, 13, Dorsal and ventral views of two specimens. Middle Eocene, Xaval Auxiliarj' Air Station well, Washington, X. C., 115-120 feet. U.S.X.M. 560619_ ________ ________________________________ 24

14. Clithrocytheridea sp. Right side of a delicate, thin-shelled specimen, X 82. Lower Eocene, Esso Standard Oil

Co. Hatteras Light well no. 1, core, 2,593-2,603 feet. U.S.X.M. 560620____________________ ..__ 24

15. Loxoconcha cf. L. creolensis Howe and Chambers. Right side of a somewhat recrystallized shell, X 106.

Middle Eocene, Xaval Auxiliary Air Station well, Washington, X. C., 90 feet. U.S.X.M. 560621_____ 27 

16-17. Loxoconcha sp. aff. L. claibornensis Murray. Left side and dorsal views of two specimens, X 100. Middle

Eocene, Xaval Auxiliary Air Station well, Washington, X. C., 115-120 feet. U.S.X.M. 560622________ 26

18-19. Loxoconcha subrhomboidea Edwards. 18, Leftside, X 85 and 19 ventral view, X 70, of two specimens. Upper

Miocene, Xaval Auxiliary Air Station well, Washington, X. C., 75 feet. U.S.X.M. 560623_________ 25 

20-21. Loxoconcha edentonensis Swain n. sp. 20, Right side of holotype, X 61, U.S.N.M. 560626. 21, ventral view

of paratype, X 61, U.S.X.M. 560627. Upper Miocene, Edenton Xaval Air Base well no. 1, Chowan Co.,

X. C., 40feet__________________ ________________________________ 26

22-23. Loxoconcha cf. L. mcbeanensis Murray. Left side and dorsal views of two specimens, X 100. Middle Eocene,

Xaval Auxiliary Air Station well, Washington, X. C., 130 feet. U.S.X.M. 560628_________________ 26

24. Loxoconcha cf. L. surreala Murray. Left side of a complete shell, X 130. Middle Eocene, Xaval Auxiliary

Air Station well, Washington, X. C., 135 feet. U.S.X.M. 560629__________________________________ 27

25-27. Buntonia howei (Stephenson). Right side, left side, and ventral views of three specimens, X 112. Middle

PJocene, Xaval Auxiliary Air Station well, Washington, X. C., 115-120 feet. U.S.N.M. 560630_________ 38

28. Clithrocytheridea cf. C. caldwellensis (Howe and Chambers). Exterior of a poorly preserved left valve, X 90.

Middle Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, core 2,135-2,145 feet. U.S.N.M. 560631__ 24
GEOLOGICAL SURVEY PROFESSIONAL PAPER 234 PLATE 2

CYTHERIDAE
PLATE 3

Page '

FIGURES 1-3. Trachyleberis eras (Ulrich and Bassler) 1,3, Exterior of a male left valve and interior of a female left valve,

X53. 3 slightly retouched. Middle Miocene, Esso Standard Oil Co. Hatteras Light, well no. 1, 840-850

feet. U.SiN.M. 560632. 2, Exterior of an immature lefl valve, X53. Middle Miocene, Hatteras Light

well no. 1, 900 910 feet. U.S.N.M. 560633 _ . - _._ _. 28

4 5. Binitonia? planibasilis (IT lrich and Bassler) Left sides of male and female dimorphs, X53. Upper Miocene,

Esso Standard Oil Co., N. C., Esso well no. 2, 320-330 feet. U.S.N.M. 560634 .. _ .. 39

6. liHutonia"! ef. 11. garretti (Howe and McGuirt). Exterior of a right valve, X55. Upper Miocene, Esso Standard

Oil Co., N. C. Esso well no. 2, 400-410 feet. U.S.N.M. 560635 . _ 39

7. Trachyleberis rosetta Swain, n. sp. Right side of holotype, X55. Middle Miocene, Esso Standard Oil Co.

Hatteras Light well no. 1, 840^850 feet. U.S.N.M. 560636 . - . ___ -. 28 

8, 15. Trachytebris? martini (Ulrich and Bassler) 8. Right side of a complete carapace, X82. 15, Ventral view of a 

complete specimen, X89. Middle Miocene, Edenton Naval Air Base well no. 1, Chowaii Co., X. C., 55 feet. 

U.S.N.M. 560637 ___. _ __._.._.._ .____...__ 29

9 12. Trachyleberis? cf. 77? angulata (Sars). Exterior views of a right and a left valve, X68. 11, 12, slightly retouched. Middle Miocene, Edenton Naval Air Base well no. 4, Chowaii Co., N. C., 70 feet. U.S.X.M. 

560638 _ ._______-_ - ____-__.__ 29

13. Trachyleberis? reesiftei (Swain). Right side of a well preserved shell, X66. Upper Miocene, Harvey Neck

well, Cartcret Co., N. C., 43-46 feet. U.S.N.M. 560639. Specimen possibly reworked from Cretaceous. __ . 30 

14, 16-18. LeginniHoci/thereis irhitei Swain, n. sp. 14, ventral view of paratype, X78, 17, holotype, right side, X78. Middle 

Miocene, Edenton Naval Air Base well no. 1, Chowaii Co., N. C., 55 feet, U.S.N.M. 560640, 560641 16, right 

side of a specimen referred provisionally to this species, X64. Lower Miocene or Oligoeene, Esso Standard 

Oil Co., N. C. Esso Well No. 2, 1,400 1,410 feet. U.S.N.M. 560642. 18, left side of a paratype, X67; 

middle Miocene, Edenton Naval Air Base well no. 4, Chowaii Co., N. C., 88 feet. U.S.N.M. 560643 ._ .. 43 

19-22 Pnracylheri<lca noiloisa (Ulrich and Bassler) 19, 20, interior views of right and left valves, X83. 19 slightly 

retouched. 21, exterior of a right valve, X83. 22, exterior of an immature left valve, X83. Middle 

Miocene, Edenton Naval Air Base well no. 1, Chowaii Co., N. C., 55 feet. U.S.N.M. 560644 _____ 51
GEOLOGICAL, SURVEY PROFESSIONAL, PAPER 234 PLATE 3

CYTHERIDAE
PLATE 4

Page

FIGURE 1. Leguminocytheris whitei, Swain, n. sp. Interior view of a paratype right valve, X69. Middle Miocene, Edenton

Naval Air Base, well no. 4, Chowan Co., N. C., 88 feet. U.S.N.M. 560643-___________________---_-----_ 43

2, 3. Buntonia? mcgnirti (Howe). Right side of a male shell, and left side of a female shell, X54. Middle Eocene,

Esso Standard Oil Co. Hatteras Light well no. 1, core 1,740-1,750 feet. U.S.N.M. 560645_________ __ 40 

4-6. Buntonia? cf. B? garretti (Howe and McGuirt).. 4,6 Exterior view (X50) and interior views (X33) of a left valve. 

Middle Miocene, Esso Standard Oil Co. Hatteras Light well no. 1, 900-910 feet. U.S.N.M. 560646. 5, Exterior view (X59) of a right valve. Upper Miocene, N. C. Esso well no. 2, 400-410 feet. U.S.N.M. 560647._ 39 

7. Cytheretta porcella (Ulrich and Bassler). Interior view of a right valve, X66. Lower Miocene or Oligocene,

Esso Standard Oil Co. Hatteras Light well no. 1, 1,480-1,490 feet. U.S.N.M. 560648_____ ________ 45

8-10. Trachyleberis^ rukasi (Gooch). Right, left, and dorsal views of three specimens, X96. Middle Eocene, Naval

Auxiliary Air Station well, Washington, N. C., 115-120 feet. U.S.N.M. 560649-_________ ________ ______ 30

11. Trachyleberis? sp. aff. T? communis aquia (Schmidt). Exterior of a somewhat abraded left valve, X70. Lower

Eocene, Esso Standard Oil Co., N. C. Esso well no. 2, 1,810-1,820 feet. U.S.N.M. 560650_____ - ____ _ 31 

12, 13. Xestoleberis? ventrostriata Swain, n. sp. Right side, X90, and ventral view, X94, of holotype. Upper Miocene,

Esso Standard Oil Co. Hatteras Light well no. 1, 380-390 feet. U.S.N.M. 560659.___ _ _______________ 18

14-16, 20. Trachyleberis hilgardi (Howe and Garrett) 14, Right side of a poorly preserved, immature? example, X78; lower 

Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, 2,390-2,400 feet. U.S.N.M. 560651. 15, 16, Left 

side, X71, and dorsal view, X66, of an imperfect specimen; lower Eocene, Hatteras Light well no. 1, core 

2,531-2,541 feet. U.S.N.M. 560652. 20, Dorsal view, X80; middle Eocene, Naval Auxiliary Air Station well, 

Washington, N. C., 115-120 feet. U.S.N.M. 560661__ _____________ _______________________ 31

17, 18, 22. Trachyleberis stenzeli (Stephenson) 17, Left side of a small shell, X64; lower Eocene, Esso Standard Oil Co., N. C. 

Esso well no. 2, 1,860-1,870 feet. U.S.N.M. 560653. 18, Right side of a large, well preserved shell, X79; 

middle Eocene, Naval Auxiliary Air Station well, Washington, N. C., 135 feet. U.S.N.M. 560654. 22, Right 

side of a carapace, X79, middle Eocene, Naval Auxiliary Air Station well, 100 feet. U.S.N.M. 560655________ 32

19. Trachyleberis davidwhitei (Stadnichenko). Right side of a complete shell, X54. Lower Eocene, Esso Standard

Oil Co. Hatteras Light well no. 1, core 2,531-2,541 feet. U.S.N.M. 560656_________ ________ ___ __ 33

21. Pterygocythereis washingtonensis Swain, n. sp. Left side of holotype, X78. Middle Eocene, Naval Auxiliary

Air Station well, Washington, N. C., 135 feet, U.S.N.M. 560657_____ _____________ ___________ 41

23. Pterygocythereis sp. Exterior of a left valve, broken posteriorly, X40. Middle Eocene, Esso Standard Oil Co. 

Hatteras Light well no. 1, core 1,740-1,750 feet. Specimen lost.

24. Trachyleberis? pellucinoda (Swain). Right side of-a complete shell, X96. Middle Eocene, Naval Auxiliary Air

Station well, Washington, N. C., 130 feet. U.S.N.M. 560668___ ______________________________________ 34
GEOLOGICAL SURVEY PROFESSIONAL PAPER 234 PLATE 4

CYTHER1DAE
PLATE 5

Page

FIGUKE 1. Trachyleberis stenzeli (Stephenson). Right side of a large, well preserved valve, X 72. Middle Eocene, Naval

Auxiliary Air Station well, Washington, N. C., 130. U.S.N.M. 560660_____________-_-___-_------- ------- 32

2 5, 16. Trachtjleberis hilgardi (Howe and Garrett) 2-4. Right sides and left side of three specimens, X 78. Middle 

Eocene, Naval Auxiliary Air Station well, Washington, N. C., 115- 120 feet. U.S.N.M. 560661. 5, Right side of 

a specimen from the same well, X 78, middle Eocene, 130 feet. U.S.N.M. 560662. 16, Interior of a left 

valve, X 78, same well, 165 feet. U.S.N.M. 560663----------------------------------------_________ 31

6, 7. Trachyleberif davidwhitei (Stadnichenko). Right side of a male shell, X 85. Middle Eocene, Naval Auxiliary 

Air Station well, Washington, N. C., 115-120 feet. U.S.N.M. 560664. 7, Right side of a female shell, X 79, 

middle Eocene, same wel! 5 130 feet. U.S.N.M. 560665 ______________ ,__. ____________________________ 33

8, 11-15. Trachyleberis? bassleri (Ulrich). 8, Left side of a large shell, X 74, that resembles the holotype in that the two 

ridges antcrad of median node are not strongly elevated. Middle Eocene, Naval Auxiliary Air Station well, 

Washington, N. C., 165 feet. U.S.N.M. 560666. 11 15, Right side, dorsal and ventral views, right and 

left sides of five specimens, X 74, that have somewhat higher antero-median ridges than the holotype. Eocene, 

same well, 100 feet. U.S.N.M. 560667___ ___ ___________.__--___-.____. .__-__-______-____ — -___ 34

9. Track yleberis smithvillensis (Sutton and Williams). Right side of a complete shell, X 84. Middle Eocene, Naval

Auxiliary Air Station well, Washington, N. C., 130 feet. U.S.N.M. 560668 ______________________________ 35

10. Trachyleberis? pellucinoda (Swain). Left side of an abraded shell, X 100. Middle Eocene, Naval Auxiliary Air

Station well, Washington, N. C., 165 feet. U.S.N.M. 560669 _______________________ _____________ 34

17, 18. Caudiies jacksonvillensis Swain, n. sp. Exterior of holotype, a right valve, and interior of paratype left valve.

X 81. Middle Eocene, Jacksonville Tent Camp, well no. 2, Onslow Co., N. C., 103-110 feet. U.S.N.M.

5(50670 and 560671. _________________________________________________ _______-______.-_-___- — ____ 42

19. Trachyleberis rrnmdorffi Swain, n. sp. Interior of right valve of holotype, X 75. Upper Miocene, Naval Auxiliary

Air Station well, Washington, N. C., 60 feet. U.S.N.M. 560672_._____._______._-___._. ._.__-_-_-_._.___ 36
GEOLOGICAL SURVEY PROFESSIONAL PAPER 234 PLATE 5

CYTflERTDAE
PLATE 6

Page

FIGURE 1. Trachyleberis pidgeoni (Berry). Right side of a complete shell, X 107 Middle Eocene, Naval Auxiliary Air Station well, Washington, N. C., 115-120 feet. U.S.N.M. 560673__ ______ __ . _.__ ___________________ 36

2, 3. Trachyleberis^ cf. T.? triplistriata (Edwards). Interior of a right valve and exterior of a left valve, X 69. Duplin

marl, Natural Well, X. C. U.S.N.M. 560674 ___. .__ .____ ______________________ 37

4. Trachyleberis mundorffi Swain, n. sp. Left side of a male paratypc, X 80. Naval Auxiliary Air Station well, Washington, X. C., 60 feet, in upper Miocene. U.S.N.M. 560675 _ _________ _______________________________ 36

5. Trachyleberis exanthemata (Ulrich and Bassler). Dorsal view of a male carapace, X 80. Duplin marl, Naval Auxiliary Air Station well, Washington, N. C., 60 feet U.S.N.M. 56067G . _ .___ ___________________________ 37

6, 7. Trachyleberis vauyhani (Ulrich and Bassler). Left side and ventral views of two specimens, X 64. Middle Miocene. Harvey Neck well, Perquimans Co., N. C., 54 feet U.S N M. 560677_________ __________________ 37

8. Trachyleberis'? rugipunctata (Ulrich and Bassler). Left side of a .veil preserved shell, X 79. Upper Miocene, Naval

Auxiliary Air Station well, Washington, N. C., 60 feet, U.S.N.M. 560678 _________________ ____ __.__ 38

9-12. Hemicythere conradi Howe and McGuirt, 9, Interior view of an immature left valve, X 91; 10, Right side, X 75, 

11, Left side, X 71, and 12, ventral view, X 81, of three mature specimens. Duplin marl, Natural Well, N. C. 

U.S.X.M. 560679___ . _.._ ___. ___ _ __ _^ _____ ___________________ 42

13, 14. Hemicythere confragosa Edwards. 13, Left, side. X 82, and 14, Ventral view, X 80, of two specimens. Upper Miocene, Naval Auxiliary Air Station well, Washington, N. C., 60 feet. U.S.N.M. 560680___________________ 43

15, 16. Legiiminocythereis cf. L. scarubaeus Howe and Law. 15, Left valve, X 60, 16, Ventral view, X 60, of two specimens.

Castle Hayne formation (u. Eocene (?)) at Pollacksville R R. Station pit, N. C U.S.N.M. 560681 __________ 43

17. Cytheretta*? sp. aff. C. plebeia (Ulrich and Bassler). Right side of a complete shell, X 59. Upper Miocene, Edenton

Xaval Air Base, well no. 1, Chowan Co., N. C., 45 feet. U.S.N.M. 560682. __ _______________________ 45

18. Leguminocylhercis clarkana (Ulrich and Bassler). Right side of a well preserved shell, X 41. Upper Miocene(?),

Bogue well no. 65, Carteret Co., N. C., 130 feet, U.S.N.M. 560683 ______________________ 43

19. Cytheretta karlana Howe and Pyeatt. Right side of a, complete shell, X 47. Middle Miocene, Harvey Neck well,

Perquimans Co., N C., 55-57 feet. U.S.N.M 560684 _ __ __ _. _ _____________ ______ __ 46

20-22. Cytheretta darensis Swain, n. sp. 20, Right side of holotype, X 64 21, 22, Right side and ventral views of two

paratypes, X 64. Middle Eocene, Esso Standard Oil Co. Hatteras Light well no. 1, core 1,740-1,750 feet. U.S.

N.M. 560685 and 560686 ____ _______ . _ _ ... __ ____ _____________ 46

23-25. Cytheretta alexanderi Howe and Chambers. 23, Right side of a shell that is damaged anteroventrally, X 46; mid

die Eocene, Esso Standard Oil Co., N. C. Esso well no 2, 1,620-1,630 feet, U.S.N.M. 560687. 24, 25, Dorsal

view and right side of two specimens, X 46; middle Eocene, Naval Auxiliary Air Station well, Washington, N.

C., lOOfeet, U.S.N.M. 560688 __ ______ ____ __ __ _____ _________ 47

26. Brachycythere cf. B. martini Murray and Hussey. Right side of a poorly preserved shell, X 45. Esso Standard

Oil Co., N. C. Esso well no. 2, middle Eocene, 1,610-1,620 feet. U.S.N.M. 560689_____ ___________________ 44
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 234 PLATE 6

CYTHERIDAE
PLATE 7

Page

FIGURE 1. Brachycylhere marylandica (Ulrich). Right side of a complete shell, X 51. Lower Eocene, Naval Auxiliary Air

Station well, Washington, N. C., 175 feet. U.S.N.M. 560690 __ _______________ _____-_ ____ 44

2-4. Paracytheridea? wetherellii (Jones) 2, Exterior of a right valve that has undergone recrystallization, X 85. Upper 

Miocene, Hatteras Light well no. 1, 320-330 feet. U.S.N.M. 560691. 3, Interior view of a right valve, X 85, 

slightly retouched. Upper Miocene, N. C. Esso well no. 2, 340-350 feet. U.S.N.M. 56C692. 4, Exterior of a 

right valve, X 85. Upper Miocene, Hatteras Light well no. 1, 330-340 feet. U.S.N.M. 560693_________ 51 

5, 6. Basslerites cf. B. miocenicus (Howe). Right side and dorsal views of two shells, X 58. Middle Miocene, Williamston test well no. 2, Martin Co., N. C., 90-95 feet. U.S.N.M. 560694_________________________ 47

7-9. Brachycythere cf. B. hadleyi Stephenson, 7, 9, Right side and ventral views of a complete shell, X 72; Paleocene(?), 

Esso Standard Oil Co., N. C. Esso well no. 2, 2,150-2,160 feet. U.S.N.M. 560695. 8, Exterior of a left valve, 

X 42, Paleocene(?), N. C. Esso well no. 2, 2,060-2,070 feet. U.S.N. M. 560696_______. ___________ 44 

10. Brachycythere cf. B. jessupensis Howe and Garrett. Right side of a complete shell, X 37. Middle Eocene, Naval

Auxiliary Air Station well, Washington, N. C. 160 feet. U.S.N.M. 560697________________________ 45

11. 13. Cytheropteron cf. C. subreticulatum van den Bold. Exterior of right and interior of left valve of a well preserved 

specimen, X 81. Upper Miocene, Naval Auxiliary Air Station well, Washington, N. C., 60 feet. U.S.N.M. 

560698__.___ _____. ___ _._______. _"__.._____..._________________-_________ 48

12, 14, 15. Cytheropteron cf. C. oariosum Martin. Left side, ventral and dorsal views of three specimens, X 102. Middle

Eocene, Naval Auxiliary Air Station well, Washington, N. C., 135 feet. U.S.N.M. 560699_.__________ 48

16. Eocytheropteron? sp. Exterior of a left valve, X 88. Upper Miocene, Esso Standard Oil Co., N. C. Esso well

no. 2, 380-390 feet. U.S.N.M. 560700________._________________________....________ 47

17. Cytheropteron sp. (a) Exterior of a recrystallized left valve, X 90. Upper Miocene, Esso Standard Oil Co. Hatteras

Light well no. 1, 330-340 feet. U.S.N.M. 560701______________________.._______________ 48 

18, 19. Cytkeromorpha cf. C. warneri Howe and Spurgeon. Left and right side of probable male and female dimorphs,

X 95. Upper Miocene, Naval Auxiliary Air Station well, Washington, N. C., 60 feet. U.S.N.M. 560702__ 49

20. Cytheromorpha cf. C. eocenica Stephenson. Right side of a well preserved shell, X 96. Middle Eocene, Naval

Auxiliary Air Station well, Washington, N. C. 130 feet. U.S.N.M. 560703________________________ 49

21. Buntonia? cf. B? lacunosa (Jones). Left side of a complete carapace, X 81. Middle Eocene, Naval Auxiliary Air

Station well, Washington, N. C., 130 feet. U.S.N.M. 560704____________________.....______ 39

22. Cytheromorpha curia Edwards. Right side of a shell, X 90. Upper Miocene', Naval Auxiliary Air Station well,

Washington, N. C., 60 feet. U.S.N.M. 560705_____________ ___________________________ 49

23. Monoceratina cf. M. harrisi Stephenson. Left side of a complete shell, X 95. Middle Eocene, Naval Auxiliary

Air Station well, Washington, N. C., 90 feet. U.S.N.M. 560706________________ ______________ 51 

24, 25. Cytkerura elongata Edwards. Left side and ventral view of two specimens, X 67. Upper Miocene, Edenton

Naval Air Base, well no. 1, Chowan Co., N. C., 45 feet. U.S.N.M. 560707_.._____________________ 50

26. Cytkeromorpha? sp. Left side of a complete shell, X 102. Middle Eocene, Naval Auxiliary Air Station well,

Washington, N. C., 130 feet. U.S.N.M. 560708-_______________________________________„ 49

27. Cytherura sp. aff. C. washburni Stephenson. Lef o side of a somewhat abraded specimen, X 102. Middle Eocene,

Naval Auxiliary Air Station well, Washington, N. C., 135 feet. U.S.N.M. 560709___________________ 50
GEOLOGICAL SURVEY PROFESSIONAL, PAPER 234 PLATE 7

CYTIfERIDAE