Biostratigraphy of the Middendorf 

Formation (Upper Cretaceous) in a 

Corehole at Myrtle Beach, South Carolina 

U.S. GEOLOGICAL SURVEY BULLETIN 2030 

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Biostratigraphy of the Middendorf 

Formation (Upper Cretaceous) in a 

Corehole at Myrtle Beach, South Carolina 

By GREGORY S. GOHN, HARRY J. DOWSETT, and 

NORMAN F. SOHL 

Prepared in cooperation with the South Carolina Water 

Resources Commission 

Biostratigraphic analysis of Santonian microfaunas and 

macrofaunas in a subsurface marine facies of the 

Middendorf Formation 

U.S. GEOLOGICAL SURVEY BULLETIN 2030 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, Jr., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names in this publication is for 

descriptive purposes only and does not imply endorsement by the 

U.S. Government 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1992 

For sale by 

Book and Open-File Report Sales 

U.S. Geological Survey 

Federal Center, Box 25286 

Denver, CO 80225 

Library of Congress Cataloging in Publication Data 

Gohn, Gregory S. 

Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a corehole 

at Myrtle Beach, South Carolina I by Gregory S. Gohn, Harry j. Dowsett, 

and Norman F. Soh I. 

p. cm.-(U.S. Geological Survey bulletin ; 2030) Prepared in cooperation 

with the South Carolina Water Resources Commission. 

Includes bibliographical references. 

Supt. of Docs. no. : I 19.3:2030 

1. Paleontology-Cretaceous. 2. Paleontology-South Carolina-Myrtle 

Beach. 3. Foraminifera, Fossil-South Carolina-Myrtle Beach. 4. Ostracoda, Fossil-South Carolina-Myrtle Beach. 5. Mollusks, Fossil-South 

Carolina-Myrtle Beach. 6. Middendorf Formation. I. Dowsett, Harry, j. II. 

Sohl, Norman F. (Norman Frederick), 1924- . Ill. Title. IV. Series. 

QE75.B9 no. 2030 

[QE734] 

557.3 s-dc20 92-17335 

[560'.1766'0975787] CIP 
CONTENTS 

Abstract 1 

Introduction 1 

Acknowledgments 1 

Regional Stratigraphy 2 

Middendorf Formation in the Myrtle Beach Core 3 

Paleontology 3 

Previous Work 3 

Planktic Foraminifers and Calcareous Nannofossils 4 

Ostracodes 6 

Macrofossils 7 

Biostratigraphic Summary 8 

Biofacies and Paleoenvironments 8 

Taxonomic Notes 8 

Foraminifera 8 

Mollusca 9 

Ostracoda 9 

References Cited 10 

PlATES 

[Plate follows References cited] 

1. Stratigraphically important fossils from the Middendorf Formation. 

FIGURES 

1. Regional map showing localities in the South Carolina Coastal Plain 2 

2. Map showing the location of the H0-973 corehole and two water wells in the 

Myrtle Beach area 2 

3. Electric log, sample distribution, contacts, and nomenclature for the Middendorf Formation 4 

4. Electric-log cross section showing the distribution of units in corehole H0-973 

and two water wells drilled at Myrtle Beach 5 

TABLES 

1. Distribution of selected stratigraphically important fossils in a corehole at Myrtle 

Beach, South Carolina 6 

Contents Ill 

Biostratigraphy of the Middendorf Formation 

(Upper Cretaceous) in a Corehole at Myrtle Beach, 

South Carolina 

By Gregory S. Gohn, Harry J. Dowsett, and Norman F. Sohl 

Abstract 

This report describes the biostratigraphy and generalized lithostratigraphy of a subsurface marine facies of 

the Upper Cretaceous Middendorf Formation encountered in a corehole drilled at Myrtle Beach, South Carolina. Whereas most outcrop and subsurface sections of 

the Middendorf Formation consist of fluvial to marginalmarine sediments containing few if any calcareous fossils, 

the section at Myrtle Beach contains abundant planktic 

foraminifers, calcareous nannofossils, ostracodes, and 

macroinvertebrates. The corehole section of the Middendorf consists of two lithologic subunits, a lower section of 

dense, olive-gray, calcareous silty clay (68ft thick) and an 

upper section of calcareous, clayey and silty, fine sand 

containing abundant bivalves (45ft). An overlying 15ft of 

grayish-olive-green, calcareous, silty and sandy clay is 

assigned to the Shepherd Grove Formation. 

Planktic foraminifers from the lower calcareous clay 

include Dicarinella concavata, Globotruncana area, Globotruncana linneiana, Marginotruncana marginata, and 

Rosita fornicata. These species indicate assignment of the 

Middendorf to the chronozones of the Dicarinella concavata Zone and the Dicarinella asymetrica Zone. The presence of the nannofossil Lithastrinus septenarius in the 

same interval indicates assignment to the chronozones of 

zones CC13 through CC16 (undifferentiated) of PerchNielsen (1985). The Santonian oyster Ostrea cretacea is 

abundant in the macrofossiliferous fine sand in the upper 

part of the formation. The ostracodes Brachycythere nausiformis, Veenia quadrialira, Schizoptocythere? compressa, 

and "Cythereis" veclitella indicate assignment of the Middendorf section to the chronozone of the Veenia quadrialira Zone of Hazel and Brouwers (1982). The presence of 

these species and chronozones and the absence of the 

single-keeled foraminiferal genus Globotruncanita and 

the nannofossil Aspidolithus parcus indicate a Santonian 

age for the Middendorf Formation at Myrtle Beach. The 

transition from microfossiliferous marine clays in the 

lower part of the Middendorf to nearshore oyster-rich 

Manuscript approved for publication April 13, 1992. 

sands in the upper part indicates a general shoalingupward trend within the unit. 

INTRODUCTION 

Calcareous fossils rarely are reported from the Upper 

Cretaceous Middendorf Formation of South Carolina. Of 

the existing reports, most refer to limited occurrences of 

fossils in marginal-marine beds. Now, however, an uncommon opportunity to study abundant calcareous fossils from 

a fully marine section of the Middendorf Formation is 

afforded by a continuously cored test hole drilled by the 

South Carolina Water Resources Commission (SCWRC) at 

Myrtle Beach, Horry County (fig. 1). In this report, we 

discuss planktic foraminifers, calcareous nannofossils, 

ostracodes, and macroinvertebrates from the Middendorf 

Formation of the Myrtle Beach core, following a brief 

review of the regional stratigraphy of that unit and a 

description of the Middendorf section in the core. 

The Myrtle Beach corehole (SCWRC-5S-fl; USGSH0-973) was drilled to a depth of 1,427 ft below a surface 

elevation of approximately 20 ft. Upper Cretaceous sediments constitute the entire corehole section between the top 

of basement-rock saprolite at 1,397 ft and the base of a 

surficial-sand unit at 80ft (Brenda Hockensmith, SCWRC, 

written commun., 1989). The drill site is located at the 

Myrtle Beach water treatment plant near the intercoastal 

waterway in the northeastern quarter of the Myrtle Beach 

7 .5-min quadrangle (fig. 2). 

Acknowledgments 

We are indebted to Joffre Castro (SCWRC) for 

providing access to the SCWRC Myrtle Beach core. We 

also wish to thank Brenda Hockensmith (SCWRC) for 

allowing us to review her lithologic descriptions of the core. 

Thanks are also extended to U.S . Geological Survey 

(USGS) Volunteer-for-Science Xenedee Bradley for preparIntroduction 
NORTH CAROLINA 

\ 

\ 

GEORGIA \ 

Figure 1. Regional map showing localities in the South 

Carolina Coastal Plain discussed in the text. The Cretaceous outcrop belt is stippled. 

ing the ostracode samples, to G. Lynn Wingard (USGS) for 

the scanning electron microscope (SEM) photographs of the 

ostracodes and mollusks, and to Kevin Foley (USGS) for 

the SEM photographs of the planktic foraminifers. Larry 

Harrelson (USGS) was of inestimable help in sampling the 

SCWRC core . 

REGIONAL STRATIGRAPHY 

The modem definition of the Middendorf Formation 

in the Cretaceous outcrop belt of North Carolina and South 

Carolina (fig. 1) was established primarily by Heron (1958) 

and Swift and Heron (1969), although this name had been 

applied intermittently to parts of the Cretaceous section in 

the Carolinas for decades (Sloan, 1907; Berry, 1914; 

Cooke, 1926; Dorf, 1952). Typical descriptions for outcrop 

sections of the Middendorf (for example, Swift and Heron, 

1969; Woollen and Colquhoun, 1977; Sohl and Owens, 

1991) refer to interbedded, noncalcareous clayey sands, 

sandy and silty clays, and quartz-pebble and clay-clast 

conglomerates, all of which occur in layers that tend to have 

lens or channel geometries. The most common sediment 

colors are light gray, white, and a variety of oxidation 

colors, although darker gray beds are locally present. 

Swift and Heron (1969) considered the Middendorf 

sediments to be a fluvial facies that grades downdip into a 

marginal-marine facies represented by outcropping sediments now assigned to the Black Creek Group. However, 

Siple and others (1956), Woollen and Colquhoun (1977), 

N 

t 

1 MILE 

I 

I 

-- -~ ...... ---- \ 

I 

! ~~ry~~~c~e~~:e I 

', 

'',,H0-218 

'',,, ',,, 

Figure 2. Location of the H0-973 corehole and two water 

wells, H0-338 and H0-218, in the Myrtle Beach area. 

Section A-A' is shown in figure 4. 

Pavich and others (1980), and Owens (1989) indicated or 

implied marginal-marine (estuarine or delta-plain) paleoenvironments for the outcropping Middendorf in South Carolina on the basis of burrows, physical sedimentary structures, and sparse microfossils. 

Recent regional studies tend to support the idea of 

lateral facies changes involving Middendorf sediments 

(Owens and Gohn, 1985; Gohn, 1990, 1992; Sohl and 

Owens, 1991) but in a manner different from that suggested 

by Swift and Heron (1969). In more recent reports, the 

concept of the Middendorf Formation is extended to include 

all of the sedimentary facies that are laterally contiguous 

and contemporaneous with the fluvial to marginal-marine 

facies of the traditional outcropping Middendorf Formation. 

That is, the Middendorf Formation, as used here, includes 

all the laterally and vertically gradational facies of a 

temporally unique sedimentary system and may consist 

locally of fluvial, marginal-marine, or marine facies. These 

facies constitute presently undefined stratigraphic subunits 

of member rank within the Middendorf Formation. 

Lithologically similar but stratigraphically higher and 

demonstrably younger sedimentary systems (sets of contiguous facies) constitute the Black Creek Group above the 

Middendorf in the outcrop belt (Owens, 1989; Owens and 

Sohl, 1989). In the subsurface near Charleston (fig. 1), two 

marine units, the Shepherd Grove Formation and the 

overlying Caddin Formation, are present between the Mid2 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
dendorf and the Black Creek Group (Gohn, 1992). Below 

the Middendorf, the Cape Fear Formation is a distinctive 

unit that everywhere consists of oxidized sands and clays 

arranged in multiple fining-upward cycles. Each cycle 

consists of a lower clayey, feldspathic quartz sand or 

gravelly sand that rests on an erosional contact and grades 

upward into an overlying red-brown silty and sandy clay 

(Heron and others, 1968; Fallaw and others, 1990; Gohn, 

1992). 

MIDDENDORF FORMATION IN THE MYRTLE 

BEACH CORE 

The contacts of the Middendorf Formation in the 

Myrtle Beach core are provisionally placed at depths of 961 

ft and 848 ft; as a result, the formation thickness is 

estimated to be 113 ft (fig. 3). The lower contact separates 

greenish-gray, abundantly microfossiliferous, calcareous 

silty clay of the Middendorf from oxidized, reddish and 

brownish clays and poorly sorted sands of the underlying 

Cape Fear Formation. The upper contact is between macrofossiliferous clayey sand of the Middendorf and graygreen, moderately fossiliferous, calcareous silty clay of the 

overlying Shepherd Grove Formation. 

The Middendorf section at Myrtle Beach consists of 

two lithologic subunits. Dense, olive-gray to dark-greenishgray, dominantly massive to bioturbated, calcareous silty 

clay is present from the basal contact at 961 ft to about 893 

ft. This 68-ft-thick clay contains abundant foraminifers, 

calcareous nannofossils, and ostracodes but only sparse 

macrofossils. Laminations of quartz silt and very fine sand 

are sparse near the base but increase upward in this interval. 

Between 893 ft and the upper contact at 848 ft, the 

Middendorf consists of 45 ft of dark-greenish-gray to 

olive-gray to medium-dark-gray, macro- and micro fossiliferous, clayey and silty, very fine to fine sand. The abundant 

macrofauna in this interval is dominated by small oysters 

that are locally concentrated in shell beds, some of which 

are indurated. Ostracodes are moderately abundant in this 

interval; however, benthic foraminifers are less common 

than below 893 ft, and planktic foraminifers are very 

sparse. 

Above 848 ft, a 15-ft-thick section of grayish-olivegreen, calcareous, silty and (very fine) sandy clay is 

assigned to the Shepherd Grove Formation. This clay 

contains trace amounts of silt- and sand-size lignitic plant 

material, mica, pyrite, sparse mollusk fragments, and 

moderately common ostracodes; no foraminifers were 

noted. This Shepherd Grove clay is similar lithically to the 

clay in the lower part of the Middendorf Formation but has 

a significantly reduced faunal and floral diversity and 

abundance. 

The distribution of the Middendorf Formation and 

Shepherd Grove Formation, and parts of the Cape Fear 

Formation and Black Creek Group, in the immediate Myrtle 

Beach area is shown on the cross section in figure 4. The 

marine clay in the lower part of the Middendorf is continuous across the section and is seen on the spontaneous 

potential logs to grade upward into the macrofossiliferous 

sands. These locally cemented, oyster-rich sands at the top 

of the Middendorf are readily discerned on the electric logs 

by their high electrical resistivities (and, where cemented, 

by high acoustic velocities on sonic logs). The fine-grained 

Shepherd Grove section above the Middendorf shows considerable variation in thickness along the line of section, 

probably owing to erosion along the base of overlying sandy 

basal deposits of the Black Creek Group. Clayey, nodular, 

glauconitic quartz sand that characterizes the Caddin Formation between the Shepherd Grove and the Black Creek in 

the Charleston area (Gohn, 1992) apparently is absent 

(eroded?) at Myrtle Beach. Low-resistivity sands and intervening clays characterize the Cape Fear section. The 

15-ft-thick fining-upward cycle at the top of the Cape Fear 

in the H0-973 corehole is particularly well displayed on the 

electric log (fig. 4). 

PALEONTOLOGY 

Previous Work 

The only report of calcareous fossils from a Middendorf Formation outcrop in South Carolina is by Siple and 

others (1956). These authors (p. 1757) reported "a scarce, 

depauperate fauna" of foraminifers from a section of black, 

carbonaceous clay and interbedded coarse sand of the 

Middendorf (their Tuscaloosa Formation) near Cheraw (fig. 

1). They considered this fauna to indicate a "basal Austin" 

or earlier Late Cretaceous age. Although Siple and others 

(1956) assigned this section to the Tuscaloosa Formation, it 

is now included in the Middendorf Formation on the 

regional map of Owens (1989); few, if any, modem 

workers still apply the name "Tuscaloosa" to outcrop 

sections in the Carolinas. 

Calcareous fossils are somewhat more common in 

subsurface Middendorf sections. Hazel and others (1977), 

Hattner and Wise (1980), and Valentine (1982) reported 

mollusks, calcareous nannofossils, and sparse foraminifers 

and ostracodes from marginal-marine sediments in the 

upper part of the Middendorf Formation (as revised by 

Gohn, 1990, 1992) of the USGS-Clubhouse Crossroads #1 

corehole, southern Dorchester County (fig. 1). Collectively, these fossils indicate a Santonian age for the Middendorf at Clubhouse Crossroads (Gohn, 1992). However, 

there are no reports of calcareous fossils from Middendorf 

sections in other stratigraphic test holes in South Carolina, 

and calcareous fossils in water-well cuttings from probable 

Middendorf sections are known only from a few wells 

(Boylan, 1982; Valentine, 1982). 

Paleontology 3 
Spontaneous 

Potential 

1--

w 

w 

LL 

Short-Normal Resistivity STRATIGRAPHIC 

UNIT 

- L____j + 

10 Millivolts 

30 

Ohm-meters 

60 

Black Creek Group 

(part) 

X Shepherd Grove Formation 

X 

X 

X 

X 

X 

Middendorf 

Formation 

Cape Fear Formation 

(part) 

X = FOSSIL SAMPLES 

Figure 3. Electric log, sample distribution, contacts, and nomenclature for the Middendorf Formation and 

associated stratigraphic units in the Myrtle Beach core. 

In contrast, palynologic studies have proved to be a 

reliable method for biostratigraphic analysis of the Middendorf Formation in outcrops and the subsurface. Several 

studies now assign the Middendorf to pollen zone V 

throughout the Carolinas and Georgia (Christopher and 

others, 1979~ Christopher, 1982a~ Prowell and others,l985). Pollen zone V, which Christopher (1979) 

divided into three formal zones, is Coniacian and Santonian 

in age (Christopher, 1982b; Gohn, 1992). At Myrtle Beach, 

pollen zone V occurs in cuttings at and below the 969- to 

953-ft interval (highest studied sample) in the lOth Avenue 

water well (H0-338, fig. 4) located about 1 mi south of the 

H0-973 corehole (R.A. Christopher, data used in Gohn 

and others, 1978). We assign the 964- to 854-ft interval in 

the lOth Avenue well to the Middendorf Formation. 

Planktic Foraminifers and Calcareous 

Nannofossils 

Planktic foraminifers were studied in three samples 

from the lower marine clay of the Middendorf Formation 

(table 1), and calcareous nannofossils were studied in three 

Middendorf samples and one Shepherd Grove Formation 

sample. The foraminifers are moderately abundant and well 

preserved at 952.5 ft and 927.0 ft but are less abundant at 

900.0 ft. Calcareous nannofossils are moderately abundant, 

are diverse, and show fair preservation at 952.5 ft and 900 

ft, whereas they are distinctly less abundant and diverse, 

and significantly less well preserved, at 848.5 ft and at 837 

ft in the Shepherd Grove Formation. 

Foraminiferal genera in the Middendorf include 

Archaeoglobigerina, Dicarinella, Globotruncana, Hedbergella, Heterohelix, Marginotruncana, and Rosita. Following the zonation of Caron ( 1985), the presence of Dicarinella concavata with Rositafornicata at 952.5 ft places this 

sample within the upper part of the chronozone of the 

Dicarinella concavata Zone or the lower part of the 

chronozone of the Dicarinella asymetrica Zone. The presence of Globotruncana area with D. concavata and R. 

fornicata at 927.0 ft restricts this sample to the middle of 

the chronozone of the Dicarinella asymetrica Zone. The 

absence of D. concavata and the presence of Globotruncana linneiana with Marginotruncana marginata place the 

4 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
4.05 Miles -------)-3111 0.95 Mile A' 

H0-338 •

Spontaneous tu 16 Inch Normal Potential w 

U-

~,. l .) ... , 

< > H0-218 H0-973 

Spontaneous 

~ _[__ ~ Spontaneous 1- STRATIGRAPHIC 

Potential Single Point 0 Potential ~ 16 Inch Normal UNIT 0 

~ ~ I 00 

~ ~ I<( Black Creek 

~ ( Group (part) !> ~ 

Shepherd Grove 

1 \. ( \ j \_ Formation .-

I 0 ' { '-..... DATUM _1 <.......... 0 

J: ~ ~ a> ? 

2_ -~ ~ { f 0 1 0 f 0 ~ Middendorf ( ; a> 

~ 0 ~ a> 

) Formation 

) I \ \ I 

.I I I I i 

J tl J - L_____j + 0 10 --- 10 Millivolts Ohm-meters 

~ } 

~ l Cape Fear 

~ g ~ Formation 

0 (part) 0 

<... ~ I I \. ~IJ I 

- L__j + 

20 Millivolts 

20 40 - L__j + 30 

Ohm-meters 10 Millivolts Ohm-meters 

Figure 4. Electric-log cross section showing the distribution of the Cape Fear Formation (part), Middendorf Formation, 

Shepherd Grove Formation, and Black Creek Group (part) in corehole H0-973 and two water wells drilled at Myrtle 

Beach. The location of the cross section is shown in figure 2; depths are in feet. Drill hole H0-973 is the cored section 

described in this report. Datum is the Middendorf-Shepherd Grove contact. 

900.0-ft sample in the upper part of the chronozone of the 

Dicarinella asymetrica Zone. 

The ages of these foraminiferal zones, and the ages of 

the calcareous nannofossil and ostracode zones discussed in 

following sections, depend in large part upon which biostratigraphic datum is chosen to mark the SantonianCampanian Stage boundary. Foraminiferal zonations published during the past decade are about evenly divided 

between using the first appearance datum of the singlekeeled genus Globotruncanita (and particularly the first 

appearance of G. elevata) or the younger extinction datum 

of the genus Dicarinella (and particularly D. asymetrica) to 

mark the stage boundary. Among nannofossil workers, the 

first appearance of Aspidolithus parcus is frequently taken 

to indicate the Santonian-Campanian boundary. Dowsett 

( 1989) recently considered the distribution of these and 

other planktic species relative to the stage boundary and 

included their distribution in the European stratotypes of the 

Santonian and Campanian Stages. We follow his preference 

for using the first appearance datum of Aspidolithus parcus, 

which occurs between the two foraminiferal datums, to 

mark the stage boundary. 

Accordingly, the Middendorf samples at 952.5 ft and 

927.0 ft assigned to the upper Dicarinella concavata or 

lower to middle Dicarinella asymetrica chronozones are of 

Santonian age. The sample at 900.0 ft assigned to the upper 

part of the Dicarinella asymetrica chronozone is early 

Campanian in age. Alternatively, the decreased abundance 

of foraminifers at 900.0 ft, compared to lower in the 

Middendorf, and the general shoaling-upward nature of the 

section, suggests that Dicarinella concavata may be absent 

at 900.0 ft only for environmental reasons. In that case, the 

entire marine clay in the lower part of the Middendorf 

would be Santonian. The presence of Heterohelix reussi in 

all three samples also supports a Santonian (or older) age 

(table 1), according to some authors (for example, Caron, 

1985), but not according to others (for example, Pessagno, 

1967). 

A Coniacian and Santonian age for at least the lower 

part of the Middendorf section also is suggested by the 

Paleontology 5 
Table 1. Distribution of selected stratigraphically important fossils in a corehole at Myrtle Beach, South 

Carolina 

[Numbers are sample depths in feet. X, present; -, absent. Unmarked columns indicate unstudied samples] 

952.5 

Foraminifers 

Archaeoglobigerina cretacea X 

Dicarinella concavata X 

Globotruncana area 

Globotruncana linneiana 

Heterohelix reussi X 

Marginotruncana marginata X 

Rosita fornicata X 

Calcareous nannofossils 

Calculites ovalis X 

Eiffellithus eximius X 

Lithastrinus septenarius X 

Marthasterites furcatus X 

Mollusks 

Anomia argentaria 

Camptonectes sp. 

Lima acutilineata? 

Lima cf. L. oxypleura 

Lima sp. 

Ostrea cretacea 

Ostracodes 

Asciocythere macropunctata 

Brachycythere nausiformis X 

"Cythereis" veclitella X 

Schizoptocythere? compressa X 

Veenia quadrialira X 

calcareous nannoflora. Samples at 952.5 ft and 900 ft 

contain Lithastrinus septenarius in addition to other species, some of which are listed in table 1. Perch-Nielsen 

(1985) restricts L. septenarius (seven-rayed species of 

Lithastrinus) to her Coniacian and Santonian zones CC13 

through CC16. The absence of Aspidolithus parcus in these 

samples and at 848.5 ft and 837ft also supports an age older 

than Campanian for the Middendorf Formation and the 

lower part of the Shepherd Grove Formation, although the 

poor preservation and low diversity of the nannofloras in the 

two higher samples make this assertion questionable in part. 

Regionally, Dowsett (1989) recorded the Dicarinella 

asymetrica Zone in the Tombigbee Sand Member of the 

Eutaw Formation and in the basal part of the overlying 

Mooreville Formation (with Aspidolithus parcus) at Plymouth Bluff, eastern Mississippi (also see Smith and 

Mancini, 1983). Planktic foraminifers of Santonian age 

rarely are reported from the Atlantic Coastal Plain, due in 

large part to the predominantly marginal-marine nature of 

Santonian sediments throughout this province. An exception is Zarra's (1989) report of Dicarinella concavata, D. 

primitiva, and additional species of Dicarinella and Marginotruncana from the subsurface of eastern North Carolina. 

927.0 900.0 886.5 876.0 851.0 848.5 

X 

X 

X 

X X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

X X 

X 

X X X 

X 

X X X X 

X 

X X X 

Ostracodes 

Ostracodes were examined from six Middendorf Formation samples and one Shepherd Grove Formation sample 

(837 ft) of the Myrtle Beach core (table 1). Specimens are 

v ... eil preserved and abundant in all six samples; at the lower 

three depths, hundreds of valves were recovered from dry 

samples as small as 100 g. 

Stratigraphically important species in the Middendorf 

samples include Brachycythere nausiformis, "Cythereis" 

veclitella, Schizoptocythere? compressa, and Veenia 

quadrialira (table 1). These species indicate assignment of 

the studied Middendorf section to the chronozone of the 

Veenia quadrialira Interval Zone of Hazel and Brouwers 

(1982~ also see Dowsett, 1989). Brachycythere nausiformis 

is restricted to the Veenia quadrialira Zone on the range 

charts of Hazel and Brouwers (1982), and the lowest 

occurrence of V. quadrialira defines the base of that Zone. 

The lowest occurrence of S.? compressa is also at the base 

of the V. quadrialira Zone. "Cythereis" veclitella occurs 

throughout this Zone and in the over- and underlying zones. 

Most of the Middendorf and Shepherd Grove ostracodes represent undescribed species. The Cytherideidae are 

6 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
represented by several undescribed forms, including 

three moderate-size species of Haplocytheridea. A small 

suboval species that has large pits and an antimerodont 

hinge resembles species of Antibythocypris and Clithrocytheridea, although described Coastal Plain species of 

these genera are significantly younger than the faunas 

described here. A large, rounded species that has abundant 

small pits on the lateral surface and an indistinct dorsomedian sulcus is tentatively assigned here to Fossocytheridea? 

new species 1. In addition to these undescribed forms, 

three valves of Asciocythere macropunctata were found at 

848.5 ft. 

Two new species of Fissocarinocythere also are 

present. Fissocarinocythere new species 1 from the Middendorf is more strongly inflated than F. pittensis and is 

smaller than F. gapensis. This new species also differs from 

these described species in the position of transverse ribs 

along the ventral surface. The less common Fissocarinocythere new species 2 in the Shepherd Grove is similar to 

F. gapensis but also differs in the position of ventral 

transverse ribs and in other ornamental details. Additional 

genera represented by undescribed species include Brachycythere (two species), Orthonotacythere, Eocytheropteron, 

and Loxochoncha. Specimens representing several species 

of Cytherella are common to abundant at and below 886.5 

ft but are absent at 848.5 ft and very sparse in the Shepherd 

Grove at 837.5 ft. 

Following Dowsett (1989), the first appearance 

datum of the calcareous nannofossil Aspidolithus parcus is 

equated with a very low position in the Alatacythere 

cheethami Zone above the Veenia quadrialira Zone. On this 

basis, the Veenia quadrialira Zone is Santonian in age. 

Regionally, Hazel and Brouwers (1982, p. 168) placed the 

"upper part of the unnamed marly chalk of the Austin Group 

in central Texas," part or all of the Bonham Marl of 

northeast Texas, and part of the Tokio Formation of 

southwest Arkansas in the Veenia quadrialira Interval 

Zone. Dowsett (1989) placed the lower part of the Tombigbee Sand Member of the Eutaw Formation in the 

Mississippi-Alabama border area within the Veenia quadrialira Zone. 

Swain (1952), Brown (1958), and Brown and others 

(1972) reported Brachycythere nausiformis from numerous drill holes in eastern North Carolina; for example, 

Brown's (1958) report of B. nausiformis in the Clarendon 

Waterworks well in Wilmington. This distribution of B. 

nausiformis, as well as Zarra's (1989) report of Santonian 

foraminifers, suggests that marine or marginal-marine 

facies of the Middendorf are fairly extensive in North 

Carolina. Indeed the type localities of Brachycythere nausiformis, Veenia quadrialira, and Asciocythere macropunctata are the Esso Standard Oil-Hatteras Light number 1 and 

number 2 wells in Dare County, N.C. (Swain, 1952). 

Macrofossils 

Macrofossils were studied in three Middendorf Formation samples from the upper half of the unit (table 1). 

Mollusks are abundant and well preserved in all three 

samples, and a variety of other macro faunal elements also is 

present. 

The oyster Ostrea cretacea Morton strongly dominates the mollusk fauna. Anomia argentaria, Camptonectes 

sp., and species of Lima are present in significantly smaller 

numbers. A single internal mold of a snail, probably a 

turritellid, was noted at 851.0 ft. Additional macrofossils 

include branching and encrusting bryozoa, encrusting and 

free serpulid worms, Clione-sponge and barnacle borings in 

the oysters, worn bone fragments, fragments of shark and 

crocodillian teeth, a single barnacle plate (at 848.5 ft), and 

fish scales. 

From a biostratigraphic standpoint, the only significant macrofauna! species is Ostrea cretacea. Its type 

locality is in the Tombigbee Sand Member of the Eutaw 

Formation at Erie Bluff on the Tombigbee River, Ala. 

(Stephenson, 1923, p. 135). In western Alabama, 0. 

cretacea occurs through about 10 to 15 ft of strata, but 

eastward in areas near the Chattahoochee River valley in 

Russell County, it ranges through about 130 ft of section. 

All of the outcrop occurrences of Ostrea cretacea in the 

eastern Gulf Coastal Plain appear to be in Santonian strata 

(Sohl and Smith, 1980). 

Along the Atlantic seaboard, the only outcrop occurrence of 0. cretacea is in the Magothy Formation of New 

Jersey, from which an internal mold of dubious affinities 

was assigned to this species by Weller (1907, pl. 42, fig. 

11). Although this taxonomic assignment cannot be satisfactorily determined, its stratigraphic position in the Cliffwood beds of the Magothy is compatible with its known 

stratigraphic range elsewhere. 

Undoubted specimens of Ostrea cretacea have been 

reported from the subsurface of the Carolinas. Stephenson 

(1923, p. 136; 1956, p. 240) reported 0. cretacea in 

cuttings at and below 1, 725 ft from the Charleston Consolidated Railway and Lighting Company well in Charleston, 

S.C. In North Carolina, he recorded this species from 

cuttings of the Clarendon Waterworks well, Wilmington, at 

and below depths of 720ft, and from 1,365 to 1,380 ft in 

the Fort Caswell well. The Clarendon well is the same well 

from which Brown (1958) reported Brachycythere nausiformis as high as 840ft (samples were unavailable to Brown 

from 840 to 670 ft). 

Ostrea cretacea also occurs in cores from a sand in 

the upper part of the Middendorf Formation (as revised by 

Gohn, 1992) in the USGS-Clubhouse Crossroads #1 corehole. At Clubhouse Crossroads, 0. cretacea occurs about 

40 ft below the highest occurrence of the nannofossil 

Eprolithus floralis (reported as Lithastrinus floralis) in the 

overlying Shepherd Grove Formation (Hazel and others, 

Paleontology 7 
1977; Hattner and Wise, 1980; Gohn, 1992). Perch-Nielsen 

( 1985) placed the highest occurrence of E. floral is at the top 

or within the Santonian. In addition, Valentine (1982, p. 

18) reported a "rich Santonian (nannofossil) assemblage" 

from just below the interval containing 0. eretaeea. 

Biostratigraphic Summary 

The planktic foraminifers, calcareous nannofossils, 

mollusks, and ostracodes from the Middendorf Formation 

of the Myrtle Beach core collectively indicate a Santonian 

age. The marine clay in the bottom half of the formation 

yields foraminiferal faunas assignable to the chronozones of 

the Diearinella eoneavata and Diearinella asymetriea 

Zones, nannofloras assignable to the chronozones of zones 

CC13 through CC16, and ostracode faunas that represent 

the chronozone of the Veenia quadrialira Zone. The chronozone of the Veenia quadrialira Zone also is present in the 

mollusk -rich clayey sands of the upper part of the formation 

that contain abundant specimens of the Santonian oyster 

Ostrea eretaeea. Biostratigraphic correlation of the Middendorf Formation with the Eutaw Formation of Alabama is 

strongly suggested by comparison of their respective faunas 

and floras (Sohl and Smith, 1980). 

Biofacies and Paleoenvironments 

The lithologic and paleontologic information for the 

Middendorf Formation section at Myrtle Beach suggests an 

upward trend in sedimentary paleoenvironments from lowenergy, offshore-marine sedimentation to higher energy, 

nearshore-marine deposition. The calcareous marine clay 

that constitutes the lower part of the formation (961 to 893 

ft) contains abundant and diverse planktic faunas and floras 

and benthic faunas. An upward increase in the quartz sand 

content and an upward decrease in the abundance of 

planktic fossils suggest a shoaling transition to the overlying 

clayey, oyster-rich sands. 

The macrofauna in the shelly sands and shell beds 

between 893 ft and 848 ft suggests a nearshore-marine to 

perhaps restricted-marine environment of deposition. 

Ostrea eretaeea dominates the fauna from this interval, 

including the fragmented fraction of the studied samples. 

The amount of fragmented and worn shell material suggests 

a high-energy regime or at least periodic storm activity. The 

oyster specimens are about half the size of specimens 

commonly found in the Alabama outcrop area; this difference suggests an area either of poorer nutrient production or 

of high sedimentation rate and rapid burial. The low 

diversity of the assemblages suggests a stressed environment, possibly of lower salinity, but probably not as low as 

present-day oyster-bank environments. The presence of 

clionid sponge borings indicates at least occasional periods 

of near-normal marine salinity. 

Marine ostracodes remain abundant in the 893- to 

848-ft interval, although the numbers of benthic and planktic foraminifers are distinctly reduced. However, moderate 

changes in the composition of the ostracode faunas at the 

generic level are apparent. Species of Haploeytheridea, 

Veenia, and Braehyeythere are still present in some numbers but constitute a lower percentage of the fauna than in 

the underlying clay. Instead, species of the smooth-valved 

genus Cytherella are the dominant form at 886.5 ft, and the 

finely pitted species assigned to Fossoeytheridea? dominates and is restricted to the 848.5-ft sample. Specimens of 

Fissoearinoeythere remain common, whereas "Antibythoeypris" and ornate species of Cytheropteron and Orthonotaeythere appear only at 848.5 ft. 

The faunal component of the Shepherd Grove Formation (848 to 833 ft) is significantly reduced from that 

found in the Middendorf. Unstudied, typically fragmented 

mollusks are sparse throughout this section, and no foraminifers were noted in the ostracode sample at 837 ft. The 

ostracode fauna in that sample consists almost entirely of 

specimens representing two species of Haploeytheridea, as 

well as a few valves of Fissoearinoeythere and cytherellids. 

The reduced diversity of this assemblage may indicate a 

nearshore to perhaps marginal-marine environment. 

TAXONOMIC NOTES 

Foraminifera 

Archaeoglobigerina cretacea ( d 'Orbigny) 

Globigerina eretaeea d'Orbigny, 1840, p. 34, pl. 3, figs. 

12-14. 

Arehaeoglobigerina eretaeea (d'Orbigny). Pessagno, 1967, 

p. 317-318, pl. 70, figs. 3-7. 

Dicarinella concavata (Brotzen) 

Plate 1, figure 3 

Rotalia eoneavata Brotzen, 1934, p. 66, pl. 3, fig. b. 

Diearinella eoneavata (Brotzen). Robaszynski and Caron, 

1979, p. 71-78, pl. 54, figs. 1, 2, pl. 55, fig. 1. 

Globotruncana area (Cushman) 

Pulvinulina area Cushman, 1926, p. 23, pl. 3, fig. la-c. 

Globotruneana area (Cushman). Cushman, 1927, p. 169, 

pl. 28, fig. 15a-c. 

Globotruncana linneiana (d'Orbigny) 

Plate 1 , figures 1 , 2 

Rosa/ina linneiana d'Orbigny, 1839, p. 106, pl. 5, figs. 

10-12. 

8 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
Globotruncana linneiana (d'Orbigny). Cushman, 1931, 

p. 90. 

Heterohelix reussi (Cushman) 

Plate 1 , figures 5, 15 

Gumbelina reussi Cushman, 1938, p. 11, pl. 2, fig. 6a, b. 

Heterohelix reussi (Cushman). Pessagno, 1967, p. 263, pl. 

85, figs. 1-9, pl. 86, figs. 1, 2. 

Marginotruncana marginata (Reuss) 

Rosa/ina marginata Reuss, 1845, p. 36, pl. 8, figs. 54a, b, 

74a, b. 

Marginotruncana marginata (Reuss). Robaszynski and 

Caron, 1979, p. 107-114, pl. 63, figs. 1, 2, pl. 64, 

figs. 1, 2. 

Rosita fornicata (Plummer) 

Plate 1 , figure 4 

Globotruncana fornicata Plummer, 1931, p. 198, pl. 13, 

figs. 4-6. 

Rosita fornicata (Plummer). Robaszynski, Caron, Gonzalez, and Wonders, 1984, p. 250, pl. 38, figs. 1-5. 

Mollusca 

Ostrea cretacea Morton 

Plate 1, figures 6, 7, 10 

Ostrea cretacea Morton, 1834, p. 52, pl. 19, fig. 3. Gabb, 

1861,p. 328;Coquand, 1869,p.52,pl.23,fig~. 3,4; 

White, 1884, p. 294; Johnson, 1905, p. 10; (?)Weller, 

1907, p. 434, pl. 42, fig. 11; Stephenson, 1923, p. 

134, pl. 28, figs. 8-17; Stephenson, 1956, p. 239, pl. 

40, figs. 11, 12, pl. 42, figs. 1-17; Richards, 1958, p. 

104, pl. 16, fig. 7; Sohl and Smith, 1980, pl. 2, figs. 

3, 5. 

Remarks.-The specimens of Ostrea cretacea from 

the Myrtle Beach corehole, figured on plate 1, have a shell 

outline, surface sculpture, hinge area, and adductor scar 

form and placement that fall well within the range of 

variability of the species as illustrated by Stephenson 

( 1956). Although the specimens are smaller than those from 

the outcrop area of the Eutaw Formation figured in Stephenson ( 1956), they are comparable in size to other specimens 

assigned to the species from the subsurface of the Carolinas 

(Stephenson, 1923, pl. 28, figs. 8, 16, and 18). 

The stratigraphic range and geographic occurrence of 

the species are discussed in the section "Macrofossils." 

Ostracoda 

Brachycythere nausiformis Swain 

Plate 1, figure 13 

Brachycythere nausiformis Swain, 1952, p. 80, pl. 8, figs. 

44-47. 

Brachycythere nausiformis Swain. Howe and Laurencich, 

1958, p. 88, text fig. on p. 89; Swain and Brown, 

1964, p. 28, pl. 3, fig. 3a-c; Hazel and Brouwers, 

1982, p. 185, pl. 4, fig. 7, pl. 6, fig. 7. 

"Cythereis" veclitella (Crane) 

Plate 1 , figure 12 

Cythereis bicornis veclitella Crane, 1965, p. 219, pl. 6, 

fig. 6. 

"Cythereis" veclitella (Crane). Hazel and Brouwers, 1982, 

p. 193, pl. 2, fig. 11. 

Remarks.-"Cythereis" veclitella (Crane), 1965, 

"Cythereis" bicornis (Israel sky), 1929, and related species 

constitute a distinctive species complex that occurs in 

Santonian and early Campanian sediments of the Atlantic 

and Gulf of Mexico Coastal Plains (Hazel and Brouwers, 

1982). Quadrate members of this complex having a continuous ventrolateral carina are considered to be "Cythereis" 

veclitella (Crane) (following <;:rane, 1965). 

Fissocarinocythere new species 1 

Plate 1 , figure 9 

Remarks. -Members of this species have a quadrate 

to elongate-rhombohedral outline; the ventrolateral ridge 

curves downward at the posterior end and joins with a 

double row of coarse reticulations along the ventral margin. 

The species is more strongly inflated than Fissocarinocythere pittensis. 

Fossocytheridea? new species 1 

Plate 1 , figure 14 

Remarks. -Specimens have a suboval outline and are 

flattened ventrally. They have a densely and finely pitted 

lateral surface and a very shallow dorsomedian sulcus. 

Males (illustrated) are more broadly rounded posteriorly 

than anteriorly and are distinctly larger than females. This 

species also occurs in the Eutaw Formation at the MarvynHurtsboro road exposure, northwestern Russell County, 

Ala. (Sohl and Smith, 1980, p. 400). 

Schizoptocythere? compressa (Hazel and Paulson) 

Plate 1 , figure 11 

Taxonomic Notes 9 
Pterygocythereis (Pterygocythereis) compressa Hazel and 

Paulson, 1964, p. 1061, pl. 157, figs. 5-7; pl. 159, 

fig. 2; text figs. 2-7. 

Schizoptocythere? compressa (Hazel and Paulson). Hazel 

and Brouwers (1982), p. 180, pl. 5, fig. 2. 

Veenia quadrialira (Swain) 

Plate 1 , figure 8 

Cythereis quadrialira Swain, 1952, p. 84, pl. 9, figs. 

27-30. 

Cythereis quadrialira Swain. Howe and Laurencich, 1958, 

p. 227, text fig. on p. 227; Swain and Brown, 1964, p. 

31, pl. 3, fig. 8a-c. 

Veenia quadrialira (Swain). Hazel and Brouwers 1982, p. 

189, pl. 3, figs. 5, 9; Dowsett, 1989, p. 15, pl. 6, 

fig. 4. 

REFERENCES CITED 

Berry, E.W., 1914, The Upper Cretaceous and Eocene floras of 

South Carolina and Georgia: U.S. Geological Survey Professional Paper 84, 200 p., 29 pls. 

Boylan, D.C., 1982, Stratigraphy and depositional environments 

of the lower South Carolina Coastal Plain between Charleston 

and Hilton Head Island: Columbia, S.C., University of South 

Carolina, unpub. M.S. thesis, 106 p. 

Brotzen, F., 1934, Foraminiferan aus dem Senon Palastinas: 

Zeitschrift des deutschen V ereins zur Erforschung Palastinas, 

V. 57, p. 28-72. 

Brown, P.M., 1958, Well logs from the Coastal Plain of North 

Carolina: North Carolina Division of Mineral Resources 

Bulletin 72, 68 p., 8 pls. 

Brown, P.M., Miller, J.A., and Swain, F.M., 1972, Structural 

and stratigraphic framework and spatial distribution of permeability of the Atlantic Coastal Plain, North Carolina to 

New York: U.S. Geological Survey Professional Paper 796, 

79 p. 

Caron, M., 1985, Cretaceous planktic Foraminifera, in Bolli, 

H.M., Saunders, J.B., and Perch-Nielsen, K., eds., Plankton 

stratigraphy: New York, Cambridge University Press, p. 

17-86. 

Christopher, R.A., 1979, Normapolles and triporate pollen assemblages from the Raritan and Magothy Formations (Upper 

Cretaceous) of New Jersey: Palynology, v. 3, p. 73-121. 

---1982a, Palynostratigraphy of the basal Cretaceous units of 

the eastern Gulf and southern Atlantic Coastal Plains, in 

Arden, D.D., Beck, B.F., and Morrow, E., Second symposium on the geology of the southeastern Coastal Plain: 

Georgia Geologic Survey Information Circular 53, p. 10-23. 

---1982b, The occurrence of the ComplexiopollisAtlantopollis Zone (palynomorphs) in the Eagle Ford Group 

(Upper Cretaceous) of Texas: Journal of Paleontology, v. 56, 

no. 2, p. 525-541. 

Christopher, R.A., Owens, J.P., and Sohl, N.F., 1979, Late 

Cretaceous palynomorphs from the Cape Fear Formation of 

North Carolina: Southeastern Geology, v. 20, no. 3, p. 

145-159. 

Cooke, C.W., 1926, Correlation of the basal Cretaceous beds of 

the Southeastern States: U.S. Geological Survey Professional 

Paper 140-F, p. 137-141. 

Coquand, Henri, 1869, Monographie du genre Ostrea-Terrain 

cretace: Marseille, H. Seran, 215 p., 75 pis. 

Crane, M.J., 1965, Upper Cretaceous ostracodes of the Gulf Coast 

area: Micropaleontology, v. 11, p. 191-254. 

Cushman, J.A., 1926, Some foraminifera from the Mendez shale 

of eastern Mexico: Cushman Laboratory of Foraminiferal 

Research, Contributions, v. 2, no. 1, p. 16-26. 

---1927, Some characteristic Mexican fossil foraminifera: 

Journal of Paleontology, v. 1, no. 2, p. 147-172. 

---1931, The foraminifera of the Atlantic Ocean (pt. 8): U.S. 

National Museum Bulletin, v. 104, p. 1-179. 

---1938, Some new species of rotaliform foraminifera from 

the American Cretaceous: Cushman Laboratory of Foraminiferal Research, Contributions, v. 14, p. 66-71. 

Dorf, Erling, 1952, Critical analysis of Cretaceous stratigraphy 

and paleobotany of the Atlantic Coastal Plain: American 

Association of Petroleum Geologists Bulletin, v. 36, p. 

2162-2184. 

Dowsett, H.J., 1989, Documentation of the Santonian-Campanian 

and Austinian-Tayloran Stage boundaries in Mississippi and 

Alabama using calcareous microfossils: U.S. Geological 

Survey Bulletin 1884, 20 p. 

Fallaw, W.C., Thayer, P.A., and Price, V., 1990, Basal Coastal 

Plain deposits in southwestern South Carolina [abs.]: Geological Society of America Abstracts with Programs, v. 22, 

no. 4, p. 13. 

Gabb, W.M., 1861, Description of new species of Cretaceous 

fossils from New Jersey, Alabama, and Mississippi: Proceedings of the Academy of Natural Sciences of Philadelphia, v. 

57, p. 4--28. 

Gohn, G. S. , 1990, Evolution of lithostratigraphic concepts in the 

study of Cretaceous sediments of the Carolinas, in Proceedings, Bald Head Island Conference on Coastal Plains Geology, 2d, 1990, Savannah River region-Transition between 

the Gulf and Atlantic Coastal Plains: November 6-11, 1990, 

Hilton Head, University of North Carolina-Wilmington, p. 

39-45. 

---1992, Revised nomenclature, definitions, and correlations 

for the Cretaceous formations in USGS-Clubhouse Crossroads #1, Dorchester County, South Carolina: U.S. Geological Survey Professional Paper 1518, 39 p. 

Gohn, G.S., Christopher, R.A., Smith, C.C., and Owens, J.P., 

1978, Preliminary stratigraphic cross sections of Atlantic 

Coastal Plain sediments of the Southeastern United StatesCretaceous sediments along the South Carolina coastal margin: U.S. Geological Survey Miscellaneous Field Studies 

Map MF-1015-A, 2 sheets. 

Rattner, J.G., and Wise, S.W., Jr., 1980, Upper Cretaceous 

calcareous nannofossil biostratigraphy of South Carolina: 

South Carolina Geology, v. 24, p. 41-117. 

Hazel, J.E., and Brouwers, E.M., 1982, Biostratigraphic and 

chronostratigraphic distribution of ostracodes in the 

Coniacian-Maestrichtian (Austinian-Navarroan) in the Atlan1 0 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
tic and Gulf coastal provinces, in Maddocks, R.F., ed., 

Texas Ostracoda-Guidebook of excursions and related 

papers for the eighth International Symposium on Ostracoda: 

Houston, Texas, University of Houston, Department of 

Geosciences, p. 166-198. 

Hazel, J.E., and Paulson, O.L., 1964, Some new ostracode 

species from the Austinian and Tayloran (Coniacian and 

Campanian) rocks of the East Texas embayment: Journal of 

Paleontology, v. 38, p. 1047-1064. 

Hazel, J.E., Bybell, L.M., Christopher, R.A., Frederiksen, N.O., 

May, F.E., McLean, D.M., Poore, R.Z., Smith, C.C., Sohl, 

N.F., Valentine, P.C., and Witmer, R.J., 1977, Biostratigraphy of the deep corehole (Clubhouse Crossroads corehole 

1) near Charleston , South Carolina, in Rankin, D. W. , ed. , 

Studies related to the Charleston, South Carolina, earthquake 

of 1886-A preliminary report: U.S. Geological Survey 

Professional Paper 1028-F, p. 71-89. 

Heron, S.D., Jr., 1958, History of terminology and correlations of 

the basal Cretaceous formations of the Carolinas: South 

Carolina Division of Geology Bulletin 2, p. 770-788. 

Heron, S.D., Jr., Swift, D.J.P., and Dill, C.E., Jr., 1968, Graded 

rhythmic bedding in the Cape Fear Formation, Carolina 

Coastal Plain: Sedimentology, v. 11, p. 39-52. 

Howe, H.V., and Laurencich, L., 1958, Introduction to the study 

of Cretaceous Ostracoda: Baton Rouge, Louisiana State 

University Press, 536 p. 

Johnson, C.W., 1905, Annotated list of the types of invertebrate 

Cretaceous fossils in the collection of the Academy of Natural 

Sciences, Philadelphia: Philadelphia Academy of Natural 

Sciences Proceedings, v. 57, p. 4-28. 

Morton, S.G., 1834, Synopsis of the organic remains of the 

Cretaceous Group of the United States: Philadelphia, W .P. 

Gibbons, 84 p., 19 pis. 

d'Orbigny, A.D., 1839, Foraminiferes, in de la Sagra, R., ed., 

Histoire physique, plitique et naturelle de l'ile de Cuba: Paris, 

A. Bertrand, v. 2, 244 p. 

---1840, Memoire sur les foraminiferes de la Craie Blanche 

du Bassin de Paris: Societe Geologique de France, Memoires, 

v. 4, no. 1, p. 1-51. 

Owens, J.P., 1989, Geologic map of the Cape Fear region, 

Florence 1 ox 2° quadrangle and northern half of the Georgetown 1 ox 2° quadrangle, North Carolina and South Carolina: 

U.S. Geological Survey Miscellaneous Investigations Map 

1-1948-A, scale 1:250,000. 

Owens, J.P., and Gohn, G.S., 1985, Depositional history of the 

Cretaceous Series in the U.S. Atlantic Coastal Plain: Stratigraphy, paleoenvironments, and tectonic controls of sedimentation, in Poag, C.W., ed., Geologic evolution of the United 

States Atlantic margin: New York, VanNostrand Reinhold, 

p. 25-86. 

Owens, J.P., and Sohl, N.F., 1989, Campanian and Maastrichtian 

depositional systems of the Black Creek Group of the 

Carolinas, in Carolina Geological Society field trip guidebook, October 28-29, 1989: Raleigh, North Carolina Geological Survey, 23 p. 

Pavich, M.J., Markewich, H.W., and Dwornik, E.J., 1980, 

Hollandite and lithiophorite in burrows of Late Cretaceous 

age, northeastern South Carolina: The Canadian Mineralogist, v. 18, pt. 4, p. 529-533. 

Perch-Nielsen, K., 1985, Mesozoic calcareous nannofossils, in 

Bolli, H.M., Saunders, J.B., and Perch-Nielsen, K., eds., 

Plankton stratigraphy: New York, Cambridge University 

Press, p. 329-426. 

Pessagno, E.A., Jr., 1967, Upper Cretaceous planktonic foraminifera from the western Gulf Coastal Plain: Paleontographica 

Americana, v. 5, no. 37, p. 245-445. 

Plummer, H.J., 1931, Some Cretaceous Foraminifera in Texas: 

University of Texas Bulletin 3101, p. 109-203. 

Prowell, D.C., Christopher, R.A., Edwards, L.E., Bybell, L.M., 

and Gill, H.E., 1985, Geologic section of the updip Coastal 

Plain from central Georgia to western South Carolina: U.S. 

Geological Survey Miscellaneous Field Studies Map 

MF-1737. 

Reuss, A.E., 1845, Die Versteinerungen der bohmischen Kreideformation: E. Schweizerbartsche Stuttgart, Abteilung 1, pt. 

2, 58 p. 

Richards, H.G., 1958, Porifera, Coelenterata, Annelida, 

Echinoidea, Brachiopoda, and Pelecypoda, pt. 1 of The 

Cretaceous fossils of New Jersey: Trenton, New Jersey, 

Bureau of Geology and Topography, Paleontology ser., 266 

p., 46 pis. 

Robaszynski, F., and Caron, M., coordinators, 1979, Atlas de 

Foraminiferes planctoniques du Cretace moyen: Cahiers de 

Micropaleontologie, pt. 1, 185 p.; pt. 2, 181 p. 

Robaszynski, F., Caron, M., Gonzalez, J.M., and Wonders, A., 

1984, Atlas of Late Cretaceous planktonic foraminifera: 

Revue de Micropaleontologie, v. 26, p. 145-305. 

Siple, G.E., Brown, P.M., and LeGrand, H.E., 1956, Stratigraphic significance of Foraminifera from an outcrop of the 

Tuscaloosa Formation at Cheraw, South Carolina: Geological 

Society of America Bulletin, v. 67, p. 1757-1758. 

Sloan, Earle, 1907, Geology and mineral resources, in Handbook 

of South Carolina State: South Carolina State Department of 

Agriculture, Commerce, and Immigration, ser. 2, p. 77-145. 

Smith, C.C., and Mancini, E.A., 1983, Calcareous nannofossil 

and planktonic foraminiferal biostratigraphy, in Russell, 

E.E., Keady, D.M., Mancini, E.A., and Smith, C.C., eds., 

Upper Cretaceous lithostratigraphy and biostratigraphy in 

northeast Mississippi, southwest Tennessee, and northwest 

Alabama, shelf chalks and coastal clastics: Society of Economic Paleontologists and Mineralogists, Gulf Coast Section 

spring field trip, April 7-9, 1983, Geological Survey of 

Alabama, p. 16-28, 1 pl. 

Sohl, N. F. , and Owens, J.P. , 1991 , Cretaceous stratigraphy of the 

Carolina Coastal Plain, in Horton, J.W., Jr., and Zullo, 

V .A., eds., The geology of the Carolinas (50th anniversary 

volume, Carolina Geological Society): Knoxville, University 

of Tennessee Press, p. 191-220. 

Sohl, N.F., and Smith, C.C., 1980, Notes on Cretaceous biostratigraphy, in Frey, R. W., ed., Excursions in southeastern 

geology: Falls Church, Virginia, American Geological Institute, v. 2, p. 392-402. 

Stephenson, L. W., 1923, Invertebrate fossils of the Upper Cretaceous formations, pt. 1 of The Cretaceous formations of 

North Carolina: North Carolina Geological and Economic 

Survey, v. 5, 604 p. 

---1956, Fossils from the Eutaw Formation, Chattahoochee 

River region, Alabama-Georgia: U.S. Geological Survey 

Professional Paper 274-J, p. J227-J250. 

References Cited 11 
Swain, F.M., 1952, Mesozoic Ostracoda, pt. 2 a/Ostracoda from 

wells in North Carolina: U.S. Geological Survey Professional 

Paper 234-B, 93 p., pls. 8, 9. 

Swain, F.M., and Brown, P.M., 1964, Cretaceous Ostracoda 

from wells in the Southeastern United States: North Carolina 

Department of Conservation and Development Bulletin 78, 

55 p., 5 pls. 

Swift, D.J.P., and Heron, S.D., Jr., 1969, Stratigraphy of the 

Carolina Cretaceous: Southeastern Geology, v. 10, p. 

201-245. 

Valentine, P.C., 1982, Upper Cretaceous subsurface stratigraphy 

and structure of coastal Georgia and South Carolina: U.S. 

Geological Survey Professional Paper 1222, 33 p. 

Weller, S., 1907, A report on the Cretaceous paleontology of New 

Jersey: Geological Survey of New Jersey, Paleontology ser., 

V. 4, 1,106 p. 

White, C.A., 1884, A review of the fossil ostreidae of North 

America and a comparison of the fossil with the living forms: 

Fourth Annual Report of the U.S. Geological Survey, p. 

273-430, pls. 34-82. 

Woollen, I.D., and Colquhoun, D.J., 1977, The Black Creek and 

Middendorf Formations in Darlington and Chesterfield Counties, South Carolina, their type area: South Carolina Geological Survey Geologic Notes, v. 21, p. 164-197. 

Zarra, Larry, 1989, Sequence stratigraphy and foraminiferal 

biostratigraphy for selected wells in the Albemarle embayment, North Carolina: North Carolina Geological Survey 

Open-File Report 89-5, 48 p. 

12 Biostratigraphy of the Middendorf Formation (Upper Cretaceous) in a Corehole at Myrtle Beach, South Carolina 
PLATE 1 

Contact photographs of the plate in this report are available, at cost, from U.S. Geological Survey 

Photographic Library, Federal Center, Denver, CO 80225 
PLATE 1 

[Figures 1-5, 8-9, 11-15, bar= 100 f..l; figures 6, 7, and 10, bar= 1 em] 

Figures 1, 2. Globotruncana linneiana (d'Orbigny) (p. 8). 

1. Umbilical view. 

2. Abapertural view. 

3. Dicarinella concavata (Brotzen) (p. 8). 

Apertural view. 

4. Rosita fornicata (Plummer) (p. 9). 

Spiral view. 

5, 15. Heterohelix reussi (Cushman) (p. 9). 

5. Side view. 

15 Apertural view 

6, 7, and 10. Ostrea cretacea Morton (p. 9). 

6. Interior view, right valve. 

7, 10. Exterior views, right and left valves, respectively. 

8. Veenia quadrialira (Swain) (p. 10). 

Exterior view, left valve. 

9. Fissocarinocythere new species 1 (p. 9). 

Exterior view, left valve. 

11. Schizoptocythere? compressa (Hazel and Paulson) (p. 9). 

Exterior view, left valve. 

12. "Cythereis" veclitella Crane (p. 9). 

Exterior view, left valve. 

13. Brachycythere nausiformis Swain (p. 9). 

Exterior view, left valve. 

14. Fossocytheridea? new species 1 (p. 9). 

Exterior view, left valve. 
U.S. GEOLOGICAL SURVEY BULLETIN 2030 PLATE I 

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STRATIGRAPHICALLY IMPORTANT FOSSILS FROM THE MIDDENDORF FORMATION 

SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS 

Periodicals 

Earthquakes & Volcanoes (issued bimonthly). 

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Professional Papers are mainly comprehensive scientific reports 

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Water-Supply Papers are comprehensive reports that present 

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series covers investigations in all phases of hydrology, including 

hydrogeology, availability of water, quality of water, and use of water. 

Circulars present administrative information or important 

scientific information of wide popular interest in a format designed for 

distribution at no cost to the public. Information is usually of short-term 

interest. 

. Water-Resources Investigations Reports are papers of an 

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principal scale is 1:24,000, and regional studies are at 1:250,000 scale 

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