If you do not need this report after it has served your purpose, please return it to the Geological 

Survey, using the official mailing label at the end

UNITED STATES DEPARTMENT OF THE INTERIOR

FORAMINIFERA, DIATOMS, AND

MOLLUSKS FROM TEST WELLS

NEAR ELIZABETH CITY

NORTH CAROLINA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 189-G

UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Professional Paper 189—G

FORAMINIFERA, DIATOMS, AND MOLLUSKS FROM TEST WELLS 

NEAR ELIZABETH CITY, NORTH CAROLINA

BY

L. G. HENBEST, K. E. LOHMAN, AND W. C. MANSFIELD

Shorter contributions to general geology, 1937

(Pages 217-227)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON: 1939

For sale by the Superintendent of Documents, Washington, D. C. ------ Price 10 cents
CONTENTS

__----_--__--__----______-_-_________-___________-______--____--_____--__--_.-_-_-------_---_-___- 217

Introduction __________________________________________________________________________________________________ 217

Foraminifera, by L. G. Henbest._-___._______________._--____________-__„___„-____-____________-_--__-___-_-__-_ 218

Correlation problem-_-_--______-___-____-___________-______-___--__-____________--________-__--_-_-_---_-__ 218

Check list of species._______________________________________________________________________________________ 218

Bibliography_______________________________„___________________.__..-__.___________.____-__ 220

Diatoms, by K. E. Lohman,____________________________________________________________________________________ 221

Check list of species.____________________________________________-___________.___-_______-____^________-____ 221

Correlations --_____-________-_______-__________-___.-_____________________._-___-_-_-_______-_-_-____--_-__ 223

Depth of 30 feet._______________________.________________-__-________--__--__.__-_---_-__.---_-_-.-__ 223

Depths of 45 to 75 feet—---- — __--_--_ — -._-._-__-_--.-__-- — --_------_-___- — _---_ — _---_--- — — — - 223

Depths of 145 to 330 feet______ _________________________________________________________________.__ 223

Mollusks, by W. C. Mansfield.______.______„___ — ______-__-__--._..-__._.___-___-_ — — - — _-.____-._.-. — ...-__ 224

Character and age.________________________________________________________________________________________ 224

Depths of 12 to 30 feet___________________________________________._-_____--______-___.____-_--__-_-__ 224

Depths of 50 to 55 feet__-__-______-_______________-______-_-___-_--_--._-___-----_-_-___-_-_----_---_-_ 224

Depths of 65 to 93 feet_________-___.____________________________„_______-__-__.-_________-____ 224

Summary -______._____________________________________--__________________„-________________-______--_ 224

Related faunas in North Carolina and Virginia._______________________________________________________________ 224

Tar Ferry, N. C.__________.._____._-___-__.______.________-__„_.._-___-_____ — --.-_-_ — ..___._______ 224

Dismal Swamp Canal, N. C._____-._____-__._-_._______._________________-__---___-----_.-_--_--__-_ 224

Localities near New Bern and Beaufort, N. C_-______._-____-___________-__-___-_-_------_----_----------_ 226

Summary of results___________________________________________________________________________________________ 226

Index______-__.________.___.___________..__._____.___._.._______________.._._„._.._______-______._____.__._. 227

ILLUSTRATIONS

Page 

FIGTJKE 28. Index map of North Carolina, showing location of Elizabeth City area_____________________________________ 217

29. Map of Elizabeth City and vicinity, showing location of test wells_-____-__-__-___------__--_--_________-_ 218

n
FORAMINIFERA, DIATOMS, AND MOLLUSKS FROM TEST WELLS NEAR

ELIZABETH CITY, NORTH CAROLINA

By L. G. HENBEST, K. E. LOHMAN, and W. C. MANSFIELD

ABSTRACT

Samples from the beds penetrated by 9 test wells in the vicinity of Elizabeth City, N. C., yielded 84 species and varieties 

of Foraminifera, 100 species and varieties of diatoms, and 86 

species and varieties of mollusks. The maximum depth penetrated was 482 feet in 1 deep drilled well; the other wells uere 

jetted to various depths less than 100 feet. The beds penetrated fall into three groups—(1) marine and brackish-water 

beds assigned to the Pleistocene; (2) brackish-water beds assigned 

to the interval from Pliocene to lower Pleistocene; and (3) marine 

beds assigned to the upper Miocene. The beds in group 1 are 

correlated with Pleistocene outcrops on the Neuse River below 

New Bern, N. C., near Beaufort, N. C., about 95 miles to the 

southwest; those in group 2 with exposures made during excavations in the Dismal Swamp, about 25 miles to the northwest, 

assigned to the upper Pliocene or lower Pleistocene; and those in 

group 3 with exposures on the Roanoke River near Hamilton 

Wharf, N. C., about 65 miles to the southwest, assigned to the 

upper part of the Yorktown formation, of upper Miocene age. 

The younger beds were deposited in somewhat brackish water, 

suggestive of an estuary or lagoon, and the older beds were 

deposited under a strictly marine environment.

INTRODUCTION

In the fall of 1932 a large number of test wells were 

put down in the vicinity of Elizabeth City, N. C., under 

the supervision of S. W. Lohnian, of the Geological

Survey, for the purpose of determining the possibility 

of developing a ground-water supply that would H 

adequate for the needs of the city. The results of this 

investigation have since been published. 1

One of these wells was drilled to a depth of 482 feet, 

and the others were jetted to various depths from 25 to 

93 feet. Samples were collected from each well as 

drilling proceeded and later were shipped to the Geological Survey for examination. A great many of the 

samples contained either Foraminifera, diatoms, or 

mollusks, the study of which formed the basis of tl ^ 

present paper.

Figure 28 shows the general location of the Elizabeth 

City area, and figure 29 shows the location of the welh, 

which bear the same numbers as were given to them in 

the report cited above.

We are indebted to Mr. S. W. Lohman for the use of 

the two figures, for the collection of the samples, and for 

a considerable amount of data regarding the deptH 

and locations of the wells.

Foraminifera were found in samples from six welh, 

diatoms from one, and mollusks from eight.

i Lohman, S. W., Geology and ground water resources of the Elizabeth City area, 

North Carolina: Qeol. Survey Water-Supply Paper 773-A, 1936.

FIGURE 28.—Index map of North Carolina, showing the location of Elizabeth City.

22409—39 217
218 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1937

FIGUEE 29.—Map of Elizabeth City and vicinity, showing location of test wells.

FORAMINIFERA

By L. G. HBNBEST

A few samples of fossiliferous sand and clay from 

shallow test wells near Elizabeth City, N. C., were submitted to me by S. W. Lohman for age determination. 

Foraminifera were found in most of the samples, but they 

were rather sparsely distributed. Fortunately the shells 

were not filled with secondary mineral matter; so it 

was possible to concentrate them by flotation with 

carbon tetrachloride. The concentrates from the lower 

horizons—depths 50 to 93 feet—contained a varied 

fauna, which proved to be of Miocene age, probably 

upper Miocene. This fauna was represented by four 

samples. The remaining five samples were collected at 

depths of 12 to 25 feet and contained a less varied fauna 

of Pliocene or Pleistocene age or more probably a mixture of both.

CORRELATION PROBLEM

The more or less disconnected succession of Miocene, 

Pliocene, and Pleistocene sedimentary strata on the 

Atlantic Coastal Plain contain foraminiferal assemblages 

which have many species in common and cannot be 

distinguished by pronounced or radical differences. In 

a general way the historical changes in the assemblages 

are gradual and involved rather than abrupt; however, 

certain geographic and stratigraphic differences have

been discovered in these faunas by Cushman, Cole, and 

Ponton, that can be utilized in stratigraphic problems 

such as the one here treated if a large and varied 

foraminiferal fauna is recovered.

CHECK LIST OF SPECIES

The list on pages 219 and 220 shows the Foraminifera 

found in these samples.

In a general way the Foraminifera of the Florida 

region during and since Miocene time have belonged to 

a shallow subtropical facies, while those farther north 

lived in a cooler marine climate. This difference was 

probably related to general conditions rather than depth 

of water. Associated with the climatic differences are 

variations in faunal composition, for some of the elements in the fauna that are conspicuous and characteristic in one region are rare or absent in tl; Q. other, 

although the rocks that contain them are of supposedly 

similar age. This circumstance complicates correlation 

problems and in several places renders close correlation 

impossible. The time range of species is confusing at 

first glance, for many species of the varied, populous 

fauna of Miocene age have held over into the Pliocene 

and later time. The Pliocene in turn had a more varied 

fauna than the succeeding Pleistocene but le^s varied 

than the Miocene. Many Pliocene species persisted 

into the Pleistocene. Accordingly, it is not everywhere
FORAMINIFERA, ETC., FROM TEST WELLS NEAR ELIZABETH CITY, N. C. 219

easy to distinguish either Miocene from Pliocene or 

Pliocene from Pleistocene.

The Foraminifera obtained from wells 65 and 64 at 

depths of 65 feet and 50 to 55 feet, respectively, are so 

similar to those obtained at depths of 87 to 93 feet in 

well 71 that they evidently came from the same formation. The discrepancy in depth is reduced about 30 

percent when the dip of the rocks is taken into account. 

Specimens collected at depths of less than 25 feet 

evidently belong to a closely related succession of sediments and may be grouped together.

The stratigraphic and geographic distribution of the 

foraminiferal species are represented in the accompanying table. The table is self-explanatory, but certain of its features deserve comment. Only the forsil 

assemblage from depths of 50 to 93 feet in wells 64, 65 

and 71 contains a Miocene, probably upper Miocene, 

fauna, although many of the species would fit in a 

Pliocene fauna. The presence of Textularia candeiana 

D'Orbigny and other species of Textularia which are 

uncommon in the Pliocene; a Miocene variety of Cancris sagra (D'Orbigny); Cibicidesamericanus (Cushman),

Foraminifera in samples from test wells near Elizabeth City, N. C.

Wellno...... —— — — — ——_.._______.___.____________._________________._„

Depth (feet)... .—— — .———................................................

T. cf. T. gramen D'Orbigny _______

Quinqueloculina flexuosa D'Orbigny___ __ .

T. trigonula (Lamarck) ___ _____________ _ _ _

Articulina sagra D'Orbigny var. miocenica Cushman and Ponton

G. lactea (Walker and Jacob) var. earlandi Cushman and Ozawa

N. pompilioides (Fichtel and Moll.) __ _______ ____ ____

Elphidium fimbriatulum (Cushman) var. advenum (Cushman) _

E. poeyanum (D'Orbigny) __ _________ __ _ ___ _____

Elphidium? sp_ ____ ___________ _ ______

71

87

V

V

X

X

Y

3 sp

?

X

V

X

X 

X

V

X

X

V

?, sp

V

X

X

V

93

V

V

V

?

X

V

3sp.

X

X

vy

X

____

V

----

65

65

V

X

X

?

X

X

V

V

X

X

X

V

X

?

X

?

X

64

50-55

"•> /

X

X

X

V

----

X 

4 sp.

X

14

12-15

X

v

X

?

X

X 

X

___-

12

20

X 

X

X

X

-___

X

?

X 

X

66

25

X

X

X

----

X

X

X

X 

X

----

____

65

23-25

X

"x"

X

X 

X 

X

64

25

X

X

2 sp.

X

Previous fossil record. 

Atlantic Coastal Plain

Miocene

X 

X 

X 

X 

X 

X 

X 

X

X

X 

X

X

X 

X 

X 

X

X

X 

X

-X

X 

X 

X 

X 

X 

X 'X

X 

X

X

(')

X

X

X 

X 

X 

X

Pliocene

X 

X 

X

X 

X 

X

X

X 

X

X

?

~~x "

?

X

X 

X 

X

X

X 

X 

X 

X 

X

Pleistocere

X

X

______

?

X

X

X

X

X 

X 

X

1 Cushman's Miocene specimen is not like the post-Miocene forms in this collection.
220 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1937

Foraminifera in samples from test wells near Elizabeth City, N. C.—Continued

Wellno.----———————— — — ---—- — — — — . — — — — ———

Depth (feet)... _______________________ — . ___ _______._, .....

Buliminella elegantissima (D'0rbigny)____ ... _ Bulimina gracilis? Cushman ____________ . . .

B. marginata D'Orbigny ___ _______ ____

B. striatula Cushman ___ ____

Virgulina fusiformis Cushman___ __ _ __ _ V. cf. V. pontoni Cushman. __ ___ __ _

Loxostoma sp ________ _ _ _ _

Spirillina sp__ ____ ____ _ __ _ .

Discorbis caudeiana (D'Orbigny). , _

D. consobrina (D'Orbigny) __ _ _ D. floridana? Crshman _ ___ __ _ - _

D. orbicularis (Terquem) ____ ___ _____

D. vilardiboana (D'Orbigny) of Cushman, 1930 _ ________ _

Rotalia sp_ __________ _ __ __ _______

R. beccarii var. parkinsoniana (D'Orbigny)

R. beccarii var. tepida Cushman _ _ _ _

Eponides frigida (Cushman) var. calida Cushman and Cole

E. mansfieldi Cushman _ ___ _____ ___ ____ _________

Cibicides americanus (Cushman) _ _ _________ ______ __ ___

C. concentricus (Cushman) ____ __ _ ____________ ___ __ __

C. lobatulus (Walker and Jacob) var. ornatus (Cushman)

Acervulina cf. A. adhaerens Schulze _ _ __

Globigerinoides sp_ ____ _. __

71

87

V

2 sp.

V

X

x

X

v

V

93

V

X

X

X

?

X

vy

65

65

\f 

X

V

V

V

^/

?

V

X

3 sp

y

64

50-55

X

Y

X

X

14

12-15

X

V

V

X

v

V

x

12

20

X

?

\jf

X

X

v/

66

25

V

X

x /

X

X

65

23-25

?

X

x

64

25

X

X 

X

X

Previous fos"il record. 

Atlantic Coastal Plain

Miocene

X 

X

X

X 

X

X

V

X

X 

X 

X 

X 

X

X

X

X

X 

v

X

X

V

Pliocene

X

X

X

X

X 

1

X 

X

X

X

Pleistocene

X

X

------

x

X 

X

X

X

1 A primitive Miocene form.

whose range is Oligocene to Miocene; Massilina mansfieldi Cushman and Cahill; M. marylandica Cushman 

and Cahill; Eponides mansfieldi Cushman; and several 

others which are rare or absent in the Pliocene gives 

satisfactory evidence for Miocene age. The appearance 

of the assemblage as a whole agrees with this conclusion.

The fossils that were derived from the more shallow 

beds are clearly post-Miocene, but it is not at all easy 

to decide whether they are Pliocene or Pleistocene. The 

presence of Eotalia beccari Linne var. ornata Cushman 

especially and also of Eponides frigida (Cushman) var. 

calida Cushman and Cole is generally considered to be 

adequate evidence of post-Miocene age. The evidence 

for choosing between Pliocene and Pleistocene conflicts, 

as the table indicates. Although a faunal mixture was 

rather apparent, I was inclined to leave the question 

indeterminate, with a slight inclination in favor of 

Pliocene. The specimens from well 14, depth 12 to 15 

feet, were shown to Prof. W. Storrs Cole, who agreed 

with the conclusion that the fauna is mixed, but he was 

inclined to think that most of the evidence in that 

sample favored assignment to the lowest Pleistocene.

The known range of Guttulina lactea (Walker and 

Jacob) var. earlandi Cushman and Ozawa in the sediments of the Atlantic Coastal Plain is limited to the 

Miocene, but in the Mediterranean region this variety 

extends from Miocene to Recent. Inasmuch as careful

collecting has failed to disclose this variety in postMiocene rocks on our Atlantic coast, I am inclined to 

regard these specimens as erratics wherever they are 

found in these well samples above the Miocene zone. 

A similar problem is presented by the occurrence of 

Eponides frigida (Cushman) var. calida Cushman and 

Cole, a characteristic Pliocene and Pleistocene form 

which was found in the Miocene zone of the Elizabeth 

City test wells. The methods practiced in drill:ng these 

shallow wells make a mixture of this sort easily possible. 

As the specimens at handt>f Guttulina lactea var. earlandi 

are fragile and are perfectly preserved, it would appear 

improbable that they are redeposited fossils.

Fragments of woody tissue and a grass (?) Feed were 

found in test well 64, depth 50 to 55 feet.

BIBLIOGRAPHY

The problems touched upon in this paper are treated 

more extensively in these selected references: 

Cole, W. S., The Pliocene and Pleistocene Foraminifera of

Florida: Florida Geol. Survey Bull. 6, 1931. 

Cushman, J. A., Some Pliocene and Miocene Foraminifera of the 

Coastal Plain of the United States: Geol. Survey Bull. 676, 

1918.

Cushman, J. A., The Foraminifera of the Choctawhatchee formation of Florida: Florida Geol. Survey Bull. 4, 1930. 

Cushman, J. A., and Cahill, E. D., Miocene Foraminifera of the 

Coastal Plain of the eastern United States: Geol. Survey 

Prof. Paper 175-A, pp. 1-50, 1933.
FORAMINIFERA, ETC., FROM TEST WELLS NEAR ELIZABETH CITY, N. C. 221

Cushman, J. A., and Cole, W. S., Pleistocene Foraminifera from

Maryland: Cushman Lab. Foram. Research Contr., vol. 6,

pp. 94-100, 1930. 

Cushman, J. A., and Ponton, G. M., The Foraminifera of the

upper, middle, and part of the lower Miocene of Florida:

Florida Geol. Survey Bull. 9, 1932.

DIATOMS

By K. E. LOHMAN

The deep test well (no. 114) was the only one from 

which diatoms were obtained. The greater part of the 

samples consisted of very fine blue-green clay, fine silt, 

and some medium-coarse sand, in all of which diatoms 

were present only sparingly. A log of this well is given 

of page 14 of Water-Supply Paper 773-A. Much washing of the material was necessary, particularly of the 

fine clays, in order to obtain a sufficient concentration 

of diatoms for a fairly representative assemblage. Thus, 

although a total of 101 species and varieties, representing 41 genera, were found, it is believed that prolonged 

search on larger samples would increase this number.

Diatoms were found in all samples taken at depths 

between 30 and 75 feet. None were found between 

75 and 145 feet, below which they continued to be found 

to a depth of 330 feet. No diatoms were found in any 

samples taken at depths between 330 and 482 feet, the 

bottom of the well.

CHECK LIST OF SPECIES

The accompanying table indicates the distribution 

and frequency of occurrence of the diatoms at the 

different depths studied. The right-hand four columns 

show other significant occurrences of the same species. 

The relative abundance of the diatoms is indicated by 

the following symbols, based on the concentrated material: A, abundant; C, common; F, frequent; R, rare; 

X, present (used only in reporting work of other authors 

where relative abundance was not stated).

As all the samples received the same degree of 

concentration in preparation, the abundances indicated 

bear a fair relation to one another but have no absolute 

value.

Diatoms jrotn city test well 114, at Elizabeth City, N. C.

Depth (feet) ________ . ___ __ . _ ___ ... ___ ...... ____________ _ __

Melosira sulcata (Ehrenberg) Kiitzing_ _ . _ -

Liradiscus cf. L. circularis Hanna____--_ _____ _ . _ _ .

Pleistocene

1338

30

A

F

C

C

R 

F

C

R

Pleistocene to

Pliocene uppr 

1339

45

F 

A 

R

F

R

C

C

C 

R

F

R 

C

F 

F

F

R 

R

1340

75

R 

A 

R

F

F 

R

F

F

F

F

R

R

Upper Miocene

1342

145

F

F

F

F 

R

R

R

R

1343

175

F

F 

F

F

R

R

1344

200

C

F 

F

F

1345

250

C

F

1346

310

C

c

F

R

1347

330

C

c

F

R

R

Q

O2 

$

"3

1

W

2815

......

C

c

c

F

F

F

F

F

d

£ 

a

a 

1OS

5

x

X

"x"

X

X

ai

fa

tn

2-w 9

— —

C

c

F

""F"

R

R

F
222 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1937

Diatoms from city test ivell 114, at Elizabeth City, N. C.—Continued

Actinoptychus undulatus Ehrenberg___ _

Goniothecium rogersii Ehrenberg__ _ _

Periptera sp____ __________

Hemidiscus cf. H. simplissimus Hanna and Grant _ _ _

Rhaphoneis surirella Ehrenberg__ _ __ ____ ___

Rhaphoneis sp. aff. R. scalaris Ehrenberg_ __ _

Synedra sp. aff. S. fimbriatus Castracane__ _ _ _

Thalassiotrix longissima Cleve and Grunow_

Plagiogramma wallichianum Greville_ _____ . _

Cocconeis japonica Schmidt____ ___ ______ __ _ _____

Navicula brasiliensis Grunow ___ ____ _ ___

Navicula hennedyi W. Smith _ __ ______

Navicula humerosa var. constri eta Cleve _____

Navicula cf. N. irrorata Greville _ _ _ ______________ _

Navicula lyra Ehrenberg

Navicula lyra var. elliptica Schmidt __ __ __ ____ __

Navicula lyra var. signata Schmidt- _ _ ___ _ _

Navicula monilifera Cleve var. constricta Hustedt

Navicula pennata Schmidt- __ ____ ___ ___

Diploneis bombus Ehrenberg _ _ _

Diploneis elliptica (Kiitzing) Cleve_ __

Diploneis gemmatula (Grunow) Cleve

Diploneis gruendleri (Schmidt) Cleve _

Diploneis lineata (Donkin) Cleve

Diploneis crabro var. suspecta (Schmidt) Cleve ___

Trachyneis aspera (Ehrenberg) Cleve

Trachyneis aspera var. intermedia Grunow _

Caloneis permagna (Bailey) Cleve _

Amphora ovalis Kutzing__ _

Pleurosigma sp. _ _

Campylodiseus echeneis Ehrenberg _ __

Nitzschia circumsuta (Bailey) Grunow

Nitzschia granulata Grunow _

Nitzschia tryblionella Hantzsch

I

a 

8

o

'5 

S

1338

30

C 

R

F

R

F

C

C 

F

R

F

F

C

R

F 

R

R

R

F

0

~ §

Q> QJ

0.0

If

"S 9J

•s S E*

1339

45

F 

C 

R

F

R

R

R

R

R

C

C 

F

F 

R

F 

R

R

F 

F

R

R

C 

R 

R 

R

R

R

F

R

F

R

F 

R

R

R,

F 

R

1340

75

R

F

F

R

----

R

R 

R

R 

R

F 

R

R

F

R

R

F

R

R

Upper Miocene

1342

145

R

F 

C

F

R

F

R 

R

F

R

F

R,

F

F

F 

R

R

1343

175

F 

F

F

F

R 

R

F

R

F

F

1344

200

F 

F

A

F

F

R,

F

1345

250

F 

F

A

?

R,

R:

R:

F

F

1346

310

F 

F

C

R

R 

R

1347

330

F

F

F

?

R 

R

F

C. Horry clay,N. 

2815

R 

F 

F

F

F

F

0

R

R

R

R

R,

R.

C. N Dismal Swamp, 

"c"

F

y

y

y

y

y

X

X

____

F

*-t 

C3 

JK 

& .

a° 

I*

M

2679

C

c

F

C

F

F

F

----

~R~

----

"R"

F
FORAMINIFERA, ETC., FROM TEST WELLS NEAR ELIZABETH CITY, N. C. 223

CORRELATIONS

Depth of 30 jeet.—The assemblage obtained at a 

depth of 30 feet indicates marine deposition with a 

slight brackish-water influence, indicated by the 

presence in small numbers of such species as Diploneis 

elliptica, Campylodiscus echeneis, and Nitzschia granulala. The frequent occurrence of Triceratium javus at 

this level is a strong indication of Pleistocene age, 

probably late Pleistocene, as this species has never 

been found in older rocks on the Atlantic Coastal Plain. 

Of the 26 species of diatoms found at the 30-foot 

depth, 11, including Triceratium jams, also occur in 

the Pleistocene Horry clay near Myrtle Beach, S. C. 2 

These are listed in the accompanying table. No.definite correlation with the Horry clay is suggested by 

this comparison. It is merely offered as a check on the 

Pleistocene age assigned to the bed at a depth of 30 feet 

in the Elizabeth City well.

Depths of 45 to 75 jeet.—The diatom assemblage 

obtained at depths of 45 to 75 feet represents deposition 

in marine to somewhat brackish water. Out of a total 

of 69 species, 11 are now living in fresh or brackish 

water; the rest are marine. The water was thus more 

brackish than that indicated by the flora from a depth 

of 30 feet, and many of the diatoms found here are now 

living in brackish estuaries. This diatom flora strongly 

resembles one obtained by Woolman 3 from an excavation that was made for the purpose of widening the 

Dismal Swamp Canal in 1897-98. The diatoms were 

determined by C. S. Boyer, who listed 31 species, of 

which 18 are found in the Elizabeth City well. Of the 

remaining 13 species not found at Elizabeth City, only 

3 are diagnostic, whereas the bulk of those found are 

important and useful as a means of correlation. Woolman was of the opinion that the diatom assemblage 

from the Dismal Swamp excavation represented an 

admixture of reworked Miocene forms with some of 

uppermost Pliocene or Pleistocene age. This opinion 

was borne out by the examination of the mollusks from 

the same horizon, determined by H. A. Pilsbry and 

C. W. Johnston.4 Two species of diatoms in Woolman's list, Actinoptychus heliopelta Grunow and Aulacodiscus rogersii (Bailey) Schmidt, are characteristic of 

the Calvert formation (middle Miocene) along the 

Atlantic Coastal Plain, and the first is not known to 

occur in younger beds. The second is definitely known 

only from Miocene rocks, although Mann 5 reported it 

in a dredging off Lower California. As it has never

* Cooke, C. Wythe, The Pleistocene Horry clay and Pamlico formation near 

Myrtle Beach, S. C.: Washington Acad. Sci. Jour., vol. 27, no. 1, pp. 1-5, 1937.

3 Woolman, Lewis, Fossil mollusks and diatoms from the Dismal Swamp, Virginia 

and North Carolina; Indication of the geological age of the deposit, with notes on the 

diatoms by C. S. Boyer: Acad. Nat. Sci. Philadelphia Proc., vol. 50 (1898), pp. 414- 

428. 1889.

*Idem, p. 418.

been reported as definitely living, and as Mann gave 

no information regarding the state of preservation of 

the diatom in his material, it is possible that the Lower 

California dredging may represent reworked material, 

at least insofar as this species is concerned. 1\& 

Dismal Swamp species that are also present in the well 

are shown in the accompanying table.

The diatom flora from the well at depths of 45 to 75 

feet also shows the mixing of Miocene and later forms 

noted by Woolman, and his explanation—erosion from 

nearby Miocene diatom-bearing beds andredeposition— 

appears to be adequate here.

The absence of Triceratium javus, the lower stratigraphic position of this part of the section, and the 

striking similarity to the Dismal Swamp diatom flora 

strongly suggest a Pleistocene (probably lower Pleistocene) to upper Pliocene age for these beds.

Depths oj 145 to 330 jeet,—A marine diatom assemblage of 36 species and varieties was obtained from 6 

samples taken at depths between 145 and 330 fea-t. 

In addition to 14 species that are present in both the 

upper and lower beds, 21 species occur in the lower beds 

only. Their geologic ranges are summarized in the 

following list:

Recent to upper Miocene__________________ 9

Recent to middle Miocene.__...-__-__--____ 5

Upper Miocene only____________-_-----___ 2

Upper and middle Miocene. _______________ 3

Middle Miocene only__________ ____________ 2

21

The two species in this list whose known range is 

limited to middle Miocene (Calvert formation), Pseudopyxilla americana (Ehrenberg) Forti and Actinoptychus 

cf. A. cathedralis Brun, occurred rarely in sample 1342, 

from a depth of 145 feet. Only a fragment of the 

Actinoptychus was found, and the identification is, as 

indicated, uncertain. The probability that the beds 

at depths between 145 and 330 feet are of middle 

Miocene age is therefore extremely slight, as the two 

forms mentioned occurred only in the uppermost part 

of this interval. Negative evidence supporting the 

determination consists in the absence of a number of 

species of short geologic range but wide geographic 

distribution, known only from the middle Miocene of 

the Atlantic Coastal Plain and the Coast Kange in 

California.

All the other species found in the samples from the 

interval between 145 and 330 feet are known from rocks 

of upper Miocene age elsewhere, and five are extinct 

species known from the upper Miocene only or from 

both upper and middle Miocene. I have found 14 of

5 Mann, Albert, and Ricker, P. L., Report on the diatoms of the Albatross voyages 

in the Pacific Ocean, 1888-1904: Oontr. TJ. S. Nat. Herbarium, vol. 10, pt. 5, p. 281, 

1907.
224 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1937

the species listed in this interval at two localities on the 

Roanoke River near Hamilton Wharf, Martin County, 

N. C. (Geol. Survey diatom localities 2679 and 2680). 

The diatoms came from a buff to blue-gray silt immediately overlying a bed containing numerous mollusks 

which W. C. Mansfield 6 correlates with the upper part 

of the Yorktown formation, of upper Miocene age. 

The Hamilton Wharf species that occur in the Elizabeth 

City well are indicated on the extreme right of the 

table. The examination of the Hamilton Wharf 

material has not been completed, and it is quite probable that more species common to the two localities 

will be found.

As a result of the foregoing analysis and comparison 

the most probable age for the beds represented by the 

interval between 145 and 330 feet is upper Miocene.

No diatoms were found in any of the samples taken 

at depths between 330 and 482 feet, the bottom of the 

well.

MOLLUSKS

By WENDELL C. MANSPIELD

The fossil mollusks were taken at depths between 12 

and 93 feet below the surface from eight of the test wells 

numbered 14, 12, 66, 62, 65, 64, 18, and 114. (See 

fig. 29.) Most of the specimens are either fragments of 

shells or immature individuals of larger shells, and some 

of them can be assigned only to genera or questionably 

to species. Nearly all the specimens have a dark-gray 

or nearly black color. Some of the specimens of gastropods have coarse-grained quartz sand in their 

apertures.

CHARACTER AND AGE

A list of the species occurring at different depths is 

given in the accompanying table.

Depths of 12 to 30 feet.—Of the mollusks from depths 

between 12 and 30 feet only Eangia sp. was found below 

the 25-foot level. The fauna is assigned to the Pleistocene and agrees closely with the molluscan fauna from a 

bed above a cypress-stump bed at Geological Survey 

station 10896, in a section on the Neuse River 10 miles 

below New Bern, N. C., and from station 10892, about 

10 miles northwest of Beaufort, N. C. (See p. 226.) 

The faunas from both of these localities I have referred 

to the Pleistocene, but that from station 10892 was 

considered a little younger than the one from station 

10896.

The following species from the Elizabeth test wells are 

identical with species from either station 10896 or 10892:

Acteocina canaliculata (Say).

Terebra concava (Say).

Terebra dislocata (Say).

Mangilia cerina (Kurtz and Stimpson).

Alectrion acuta (Say).

Astyris lunata (Say).

Pandora trilineatus Say.

Tellina sayi Dall.

Donax variabilis Say.

Mulinia lateralis Say, thin form.

6 Oral communication.

At a depth of 30 feet a fragment belonging to the 

genus Eangia was taken. This genus indicates a 

brackish-water condition at this depth.

Depths of 50 to 55 feet.—The mollusks observed at 

depths between 50 and 55 feet in the well indicate a 

change in the character of the fauna. Large specimens 

of Corbula inaegualis Say occur here. The specimens 

referred to this species are as a rule small in the Pliocene 

and larger in the Miocene. An exception is to H noted, 

however, in specimens from station 8167, 3 miles southwest of Riverdale, N. C.; although I have correlated 

this locality with the Pliocene Croatan sand, the shells of 

C. inaegualis found there are larger than those commonly found in the Pliocene.

The age of the fauna occurring between depths of 50 

and 55 feet is believed to be Tertiary and msy be no 

older than Pliocene.

Depths of 65 to 93 feet.—The fauna between depths of 

65 and 93 feet, although somewhat similar to that 

between depths of 50 and 55 feet, carries fragments of 

Turritella aff. T. alticostata Conrad that are scmewhat 

similar to shells of this species in the fauna in tl ?, upper 

part of the Yorktown formation at Tar Ferrr, N. C. 

(See below.) Corbula inaequalis and Cypraeolina 

dacria Dall (the latter a Miocene and Pliocene species) 

are also found in this part of the section. Tl e fauna 

between depths of 65 and 93 feet is in most respects 

different from the late Yorktown fauna at Tar Ferry, 

there being only a few species in common. About the 

only molluscan evidence that the upper Miocene has been 

reached in the Elizabeth City wells is that afforded by 

Turritella aff. T. alticostata. I found no Turritellas like 

this form in the Croatan sand of the Pliocene.

Summary.—The ages indicated by the mollusks at 

different depths are summarized below.

Between 12 and 30 feet—Pleistocene. 

Between 30 and 50 feet—no specimens. 

Between 50 and 55 feet—Tertiary; may be Pliocene. 

Between 55 and 65 feet—no specimens. 

Between 65 and 93 feet—Tertiary; questionably referred 

to the upper Miocene.

RELATED FAUNAS IN NORTH CAROLINA AND VIRGINIA

Tar Ferry, N. C.—At Tar Ferry, Wiccacor Creek, 

about 30 miles nearly west of Elizabeth City, and at 

Colerain Landing (upper beds), Chowan Rive'-, about 

30 miles southwest of Elizabeth City, are well-exposed 

beds carrying late Yorktown faunas comparable in age 

with the Duplin marl at the Natural Well, N. C., but a 

little later in time than the upper part of the Yorktown 

as exposed in the vicinity of Suffolk, Va. A list of the 

species at Tar Ferry is given by Miller. 7

Dismal Swamp Canal, N. C.—A collection of fossils 

was obtained by me from a spoil bank along the Dismal 

Swamp Canal about 3}£ miles south of the ^irginiaNorth Carolina State line and about 16 miles a little
FORAMINIFERA, ETC., FROM TEST WELLS NEAR ELIZABETH CITY, N. C.

Species of mollusks from test wells in and near Elizabeth City, N. C.

225

Gastropods

Acteocina canaliculata (Say) var

Terebra concava (Say) ___ _

Mangelia cerina (Kurtz and Stimpson) 

Olivella mutica (Say) _ _______ _ _ Marginalia aureocincta Stearns. _

Marginalia bella (Conrad)

Marginella cf. M. limatula Conrad _

Cypraeolina dacria (Dall) __

Marginella, sp. ind_ __ _

Alectrion acuta (Say) _ _ _ _

Alectrion trivittata (Say)

Alectrion near A. obsoleta (Say) _ -

Alectrion sp. (fragment) __ ___ _

Astyris lunata (Say)_ _ ________ _

Columbella? sp __________ ___ _

Eupleura caudata (Say)? (f ragmen t)__ 

Urosalpinx aff. U. cinereus (Say)

Urosalpinx sp _ ___ ___

Epitonium sp. a__ ____ ______ ___

Epitonium sp. b ____ ___ ____ ___

Melanella sp_ __ _ _ ______ ___

Melanella sp___ _____

Turbonilla sp. a (apparently 1 sp.)

Turbonilla sp. b ___

Turbonilla sp. c_ ____ ___

Pyramidella sp_ ___

Odostomia sp__ ____ ___

Alaluna sp ___________

Seila adamsii (H. C. Lea)_ ______

Caecum regulare Carpenter, _ _ _ _

Turritella sp. a aff. T. alticostata 

Conrad (fragments) __ ____

Turritella sp. b aff. T. alticostata 

Conrad (fragments) _ __

Crepidula fornicata (Linne) _

Calyptraea sp____ _ __ _

Tectonatica pusilla (Say) _ _ _

Pelecypods 

Nucula proxima Say_ _____ __ _

Nuculana acuta (Conrad) _ _ _ _

Yoldia sp__ ________ _

Glycymeris americana (Defrance)

Pleistocene

12-25 

feet

X

X

X

X 

X

X

X

X 

X

X

X

X

X

X

X 

X

X

X

X

30 feet

Tertiary

50-55 

feet

X

X

X

X

65 

feet

y

x

X

X

X

?

X

X

X 

X

87-93 

feet

X

X

X 

X

V 

y \

X

X 

X

X

X

"x"

X

X 

X

X 

X 

X 

X

X

X 

X 

X

Pelecypods — Continued 

Glycymeris sub ovata (Say)? (young)

Area (probably more than 1 sp.) 

(young) ______________ — ________

Ostrea sp. (young) ___ _____ _ __

Pecten eboreus Conrad? (fragments) __

Crenella aff. C. glandula Totten__ _

Pandora trilineata Say _ _

Pandora sp. (fragments)-- __ __-_

Astarte cf. A. concentrica Conrad 

(fragment). _ _ ____ ______ _

Astarte sp. (fragment) _ ________

Crassinella lunulata (Conrad) _____

Venericardia granulata Say _ _

Phacoides trisulcatus (Conrad) _

Phacoides multilineatus (Tuomey and

Sportella constricta (Conrad) _ _ _

Rochefortia planulata Stimpson _

Callocardia sp_ ______ _____ _

Gemma magna Dall_ _ ____ _.___

Tellina aff. T. declivis Conrad _ _

Tellina sayi Dall_ _______________ _

Donax variabilis Say __ __ ___ ___

Ensis directus Conrad_____ __ ____

Mulinia congesta Conrad? _________

Paramya subovata Conrad- _ _

Corbula inaequalis Say _______ ___

Corbula aff. C. cuneata Say___ __

Corbula conracta Say

Pleistocene

12-25 

feet

X

y

X 

y

?

X

x

X

x

x

X

x

X

x

X

x

X

X

X

X

x

x

30 

feet

-___

X

Tertiary

50-55 

feet

X

x

X

X 

X

?

x

X

X

65 

feat

X

X

X

x

X 

X 

X

X

X 

X

X

X

X

y

87-93

feet

X

X

X

X 

X 

X

X

"x"

X 

X

x"

X

X 

X

X

X

X

X

X 

X

X

X

west of north of Elizabeth City. The following is a list 

of the species with their geologic ranges:

Marginella limatula Conrad, Miocene to Recent; same as 

Recent specimens at Smiths Island, Va.

Olivella mutica (Say), Miocene to Recent.

Busy con caricum (Gmelin), more like Pleistocene and Recent forms.

Alectrion trivittata (Say), Pliocene?, Pleistocene, and 

Recent.

Ilyanassa obsoleta (Say), Pleistocene and Recent.

Urosalpinx cinereus (Say), Pleistocene and Recent.

Vermetus sp.

Crepidula sp.

Polynices duplicatus (Say), Miocene to Recent.

Nucula proxima Say, Miocene to Recent.

Area (Noetia) limula Conrad, similar to a Pliocene Waccamaw form.

Area plicatura Conrad var., more nearly like the Pliocene 

form.

7 Miller, B. L., The Tertiary formations: North Carolina Qeol. and Econ. Survey, 

vol. 3, pp. 233, 234, 1912.

Modiolus sp.

Venericardia tridentata Say (has two or three more ribs

than the Recent northern form), probably more nearly

like the Pliocene form.

Divaricella quadrisulcata (D'Orbigny), Miocene to Recent. 

Cumingia tellinoides (Conrad), Pleistocene and Recent. 

Ensis directus Conrad, Miocene to Recent. 

Mulinia lateralis Say, Miocene to Recent, a light form and

more nearly like Pleistocene and Recent. 

Spisula sp. cf. S. procera Solander. 

Coral.

Some of the species in this list—Ilyanassa obsoleta 

(Say), Urosalpinx cinereus (Say), Cumingia tellinoides 

(Conrad), and perhaps others—appear to have b?,en 

taken from the Pleistocene, whereas other specie?— 

Area limula Conrad, Area plicatura Conrad var., Venericardia tridentata Say, and perhaps others—appear to 

have been taken from the Pliocene. The collection 

appears, therefore, to be a mechanical mixture of P' : ocene and Pleistocene species.
226 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1937

Nine of the names listed are the same as names listed 

by Woolman 8 in his "table of species of mollusks 

dredged from the Dismal Swamp Canal in North Carolina and Virginia." I have not had an opportunity to 

compare his specimens with mine.

Localities near New Bern and Beaufort, N. C.—Plio8 Woolman, Lewis, Acad. Nat. Sci. Philadelphia Proc., vol. SO, p. 418,

cene and Pleistocene faunas found in the outcrops along 

the Neuse River below New Bern and Pleistocene faunas 

from ditches 10 miles northwest of Beaufort, N. C., 

were described in 1927. 9 These localities are about 100 

miles nearly south of Elizabeth City.

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

Pliocene and Pleistocene faunas from North Carolina: Qeol. Survey Prof. Paper 

150-F, 1927.

SUMMARY OF RESULTS

Studies of the three classes of fossils have given results that are in fairly close agreement. They are summarized

below in tabular form.

Depth

(feet)

Foraminifera (wells 12, 14, 64, 65, 66, and 71) Diatoms (well 114) Mollusks (wells 12, 14, 18, 62, 64, 65, 66, aid 114)

Age Age Ecology Age Ecology

No Foraminifera. No mollusks

No diitoms.

Pliocene or Pleistocene. Pleistocene. Brackish water.

Pleistocene. Marine to brackish water.

No Foraminifera. No diatoms. No mollusks.

Pleistocene to upper PlioMiocene (probably upper).

100 —

No Foraminifera below 93 feet. No'diatoms.

200—

Upper Miocene.

300-

No diatoms below 330 feet

Pliocene (?). Marine.

Marine to brackish water. 

Estuarine. No mollusks.

Miocene (probably upper). Marine.

No mollusks below 93~feet.

Marine.
INDEX

Page 

Abstract....._----___-_.-_——————————_————_............._ 217

Actinoptychus eathedralis__-.______..._________.-_.-_ 223

heliopelta.—.-._—___..______.-___—....__________ 223

cf. A. cathedralis.---________.____________________ 223

alticostata, Turritella______.__________________--..____ 224

americana, Pseudopyxilla______-___---..._-.-_-.-.____. 223

americanus, Cibicides...._____________...___...-..--_.., 219-220

Arcalimula.____________________________.-.____._ 225

plicatura var...________.___.____._-______._____ 225

Aulacodiscusrogersii.-..__________..-_------_.......__... 223

Beaufort, N. C., faunas of...__------_-________.--______ 226

beccari, Rotalia. ___..—______....____________._______ 220

Bibliography............................................................. 220-221

calida, Eponides frigida___....________.__.___________.. 220

Calvert formation, correlation of.—____-_------__--__..__._.. 223

Campylodiscus echeneis_____...__..-._____..__________. 223 

Cancris sagra...___..__._________._—___._______ 219-220 

candeiana, Textularia__.....__.....______.______._____.. 219

cathedralis, Actinoptychus.._..._________.__.._......._------__._ 223

Cibicides americanus.__..................._____------__....__-- 219-220

cinereus, Urosalpinx___.___.........______.___.___...___ 225

Colerain Landing, N. C., faunas of., — ._____-________-___.__ 224 

Corbula inaequalis...__.._.__._____.....______....__._ 224

Cumingia tellinoides____..-____-.-.,_____.---__----------_ 225

Cypraeolina dacria..------------------__-..-.._..--_______-_.. 224

dacria, Cypraeolina_____._____....._____________.___.. 224

Diatoms, correlations of.. — ___..._______________._____ 223-224

depth of occurrence of- — ._____.______.—____..______ 226

list of species of____..______.______-______.___ 221-222

Diploneis elliptica________...____._____________._____ 223

Dismal Swamp Canal, N. C., list of species from....__....______.. 224-225

earlandi, Guttulinalactea...__-...._...___.__-___..____ 220

echeneis, Campylodiscus....__-__________.___.________ 223

elliptica, Diploneis...___.______._____...____..._____ 223

Eponides frigida calida—-— — -——_--_______--.--...___...__ 220

mansfleldi__..______._____.______-__________ 220

favus, Triceratium________.____________.___ ___._____ 223

Foraminifera, age of..___.______.________________.__ 219,226

depth of occurrence of......___..__...___.._____..___. 226

list of species of______________.______._______... 219-220 

frigida, Eponides—__.______________....________.___ 220

Gastropods, list of___..___....________—.._.——___.__ 225

granulate, Nitzschia...._____________________._______ 223

Guttulina lactea earlandi___.______..________——____._ 220

heh'opelta, Actinoptychus____________________________. _ 223 

Horry clay, age of—.————————-....————————.—————————.. 223

o

Jlyanassa obsoleta.__..._-.-_ — _________..._-.-.._..._ 225

inaequalis, Corbula-_———.-- — --—-. — -- — ————— ——— ------—— 224

lactea, Guttulina-______.___.__.______.______.____ 220

limula, Area______-______-______..._____________— 225

mansfleldi, Eponides.-._..——.-—..-_........— -.....—————— 220

Massuina—....._..—.....__. — ..———.——.___—...—— 220

marylandica, Massilina_____,__--------__._..._-———. — — _.. 220

MassUina mansfleldi________-..._-_.._____.---..___.. 220

marylandica__.________._____...__—.....———._..... 220

Miocene beds, correlation of ._____.......__---------——...._.___.._ 223

fossils from................................................. 218,219,220.22'-226

Mollusks, character and age of———.—— ——_— ——_ ————.. ——— —— 224

depth of occurrence of._____..__.--.--...---.-.....———-....—— 226 

list of species of.__............................_.__.__........ 221-225

New Bern, N. C., faunas of___._____......_______.___.. 226

Nitzscbia granulata__.______....___-__..-..„...———_..—— 223

obsoleta, Ilyanassa__.——..__.——...... — ------- —- — .-.-_— —— —— 225

ornata, Rotaliabeccari.-._....__._ ——.— ————-------------——-. 220

Pelecypods, list of.....______--„..-------...----.__..-.-.-.-.---.-. 225

Pleistocene deposits, correlation of—____-_-..-....-___—......... 223

fossilsfrom.......... ——.........-...—..——.——. — ... 218, 219, 220,22'-226

plicatura, Area, var..__..______.______._____———..———— 225

Pliocene beds, correlation of.___...__...—__-------- —— ————— —— 223

fossilsfrom.———————— ——..——— — -———— 218,219,220, TOf -226

Pseudopyxilla americana.-____..__._..__————.——— -———— 223

Eangiasp.___________________...__._....———„———— 224

rogersii, Aulacodiscus____ __._._.————.——————————————— 223

Rotalia beccari ornata.__._.__________.__....—————...——— 220

sagra, Cancris..._....._......._..„...-__..__...__-...—.. 219-220

Tar Ferry, N. C., faunas of—————————————_„......—... 224

tellinoides, Cumingia.-—.-..___...-_...———.——__.__...—— 225

Textularia..———————————————— —— --——————————— 219

candeiana-________.______._—___———————.———— 219

Triceratium favus__.___._......_..——_.—...—..——...——— 223

tridentata, Venericardia-_-—__-..._--------—... —..———— — ——.. 225

Turritella aff. T. alticostata...... ———— ———————.................... 224

Urosalpinx cinereus__..__..-- —— ------------- — —— — — — —..———— 225

Venericardia tridentata____-_____.-..__———._——.. —..—— 225

Yorktown formation, correlation of.___..—__——......—————.——— 224

227