Charles C. Williams 

U. S. Geological Survey

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UNITED STATES DEPARTMENT OF THE INTERIOR

GEOLOGY AND BIOLOGY OF 

NORTH ATLANTIC DEEP-SEA CORES

PART 4. OSTRACODA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 196-C

C 

U. S. Geological S

UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Professional Paper 196-C

GEOLOGY AND BIOLOGY OF

NORTH ATLANTIC DEEP-SEA CORES

BETWEEN NEWFOUNDLAND AND IRELAND

PART 4. OSTRACODA

BY

WILLIS L. TRESSLER

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 194]

For sale by the Superintendent of Documents, Washington, D. C. ..... . - Price 15 cents

CONTENTS

	Pagre 

Outline of the complete report_._.__ _ ______________________________________________________________________________ v

Summary of the report-____________________________________________ _______________________________________________ vn

Foreword, by C. S. Piggot-______________________________________________________________________________________ xi

General introduction, by W. H. Bradley_____________________________________________„________________-_________._ xm

Significance of the investigation,___.__________________________.._________________________„._________-_-_____-_.. xm

Location of the core stations._______________________________________________________________________________ xiv

Personnel and composition of the report- _______________________--_______-_._____________-_-______---_------_- xiv

Methods of sampling and examination-__ ___________ ._____.___._______._____._.._______._-_____________---_--_... xiv

Part 4. Ostracoda, by Willis L. Tressler _ _____ .._____________.________________-._______________-__._-_-----_______- 95

Introduction._____________________________________________________________________________________________ 95

Ecology of the ostracodes___________________________________________________________________________________ 95

Systematic descriptions of the species.__________________-__-_____-----_______________--_---___--_--------____ 97

Discussion ________________________________________________________________________________________________ 103

Index ______---.--__-__--_-____._.__________..________________ _____________ ______._________..__________._-_--_---_-- xvii

ILLUSTRATIONS

PLATE 1. Bathymetric chart of a part of the North Atlantic Ocean showing the location of the core stations,__._ ..______ xv

2. Longitudinal sections of the ail-dried cores. _____________________________________________________________ xv

18. Chart showing position of the ostracode-bearing samples in the cores and the distribution of species ______ ______ 98

19. Ostracoda from the North Atlantic deep-sea cores...___________________________________________________ 106

FIGURE 1. Profile across the North Atlantic Ocean bottom along the line of the numbered core stations._ .__..____-_-._ - xiv

TABLES

TABLE 1. Geographic location, length of cores, and depth of the water from which they were taken___ __________________ xiv

14. Geographic distribution and depth and temperature ranges of the ostracodes._______________________________ 96

15. Distribution of the ostracodes in the core samples._________________________--______--__-__-_--______---_ 97

16. Distribution of Krithe bartonensis (Jones) in the cores-----_-----_-_------_---_-------------------------_- 99

17. Distribution of Krithe tumida Brady in the cores_______-___-_-_____________---__---_-_-_--__-___-_______ 100

18. Distribution of Cythereis echinata Sars in the cores-__---___-_-_-_---_-_____-_-_-_-----------_-----_------ 100

OUTLINE OF THE COMPLETE REPORT

Foreword, by C. S. Piggot.

General introduction, by W. H. Bradley.

PART 1. Lithology and geologic interpretations, by M. N. Brumlette and W. H. Bradley.

2. Foraminifera, by Joseph A. Cushman and Lloyd G. Henbest.

3. Diatomaceae, by Kenneth E Lohman.

4. Ostracoda, by Willis L. Tressler.

5. Mollusca, by Harald A. Rehder.

6. Echinodermata, by Austin H. Clark.

7. Miscellaneous fossils and significance of faunal distribution, by Lloyd G. Henbest.

8. Organic matter content, by Parker D. Trask, H. Whitman Patnode, Jesse LeRoy Stimson, and John R. Gay

9. Selenium content and chemical analyses,'by Glen Edgington and H. G. Byers.

SUMMARY OF THE REPORT

In May and June 1936 Dr. C. S. Piggot of the Geophysical 

Laboratory, Carnegie Institution of Washington, took a series of 

11 deep-sea cores in the North Atlantic Ocean between the 

Newfoundland banks and the banks off the Irish coast. These 

cores were taken from the Western Union Telegraph Co.'s cable 

ship Lord Kelvin with the explosive type of sounding device 

which Dr. Piggot designed. In the fall of that year he invited a 

group of geologists of the United States Geological Survey to 

study the cores and prepare a report. Biologists of the United 

States National Museum, the University of Buffalo, and chemists of the United States Department of Agriculture cooperated 

in the investigation and contributed to the report.

The westernmost core of the series (No. 3) was taken in the 

blue mud zone, but all the others were taken in parts of the ocean 

where the bottom is blanketed with globigerina ooze. The 

shortest cores are No. 8, taken on the mid-Atlantic ridge in 1,280 

meters of water, and No. 11, taken where the core bit struck 

volcanic rock. The cores range in length from 0.34 to 2.93 

meters and average 2.35 meters. They were taken at depths 

ranging from 1,280 to 4,820 meters.

Lithology and geologic interpretations.—In about 20 representative samples from each core the percentages of calcium carbonate, 

clay and silt, and sand were determined and plotted, and the 

relative abundance of Foraminifera, coccoliths, and diatoms was 

estimated. Material between these guide samples was examined 

microscopically, especially in certain critical zones.

Two zones were noted in which silicic volcanic ash (refractive 

index near 1.51) is common. The upper ash zone was found in 

all the cores except No. 11, but the lower one was found only in 

the lower part of cores 4 to 7. In core 3 the upper ash zone is 

represented by shards scattered very sparsely all through the 

core, as this core, despite its length of 2.82 meters, apparently did 

not reach the bottom of the ash zone. The upper ash zone, 

together with other adjacent lithologic zones, serves to correlate 

the cores, and the lower ash zone, found west of the mid-Atlantic 

ridge, helps to confirm the correlation.

Besides the zones of volcanic ash four other zones distinctive in 

lithologic character were found. These zones are characterized 

by a relative abundance of sand and pebbles, by a smaller 

percentage of calcium carbonate, and by a sparsity of Foraminifera and coccoliths. They are distinctive also in texture. The 

pebbles are subrounded to angular and include a wide variety of 

rock types—sandstone, gneiss, soft shale, and limestone—of 

which limestone is the most common. Some of the pebbles are 

as much as 2 centimeters across. These zones are interpreted as 

glacial marine deposits formed during the Pleistocene glacial 

epoch, when continental glaciers were eroding the land. Drift 

ice from the continental glaciers apparently transported consideraable quantities of rock debris far out into the ocean basin.

Between the glacial marine zones found in the North Atlantic 

cores the sediments consist chiefly of foraminiferal ooze or marl, 

much like that which is forming today in the same area.

The uppermost glacial marine zone is represented in all the 

cores except Nos. 3 and 11 and lies just below the upper volcanic 

ash zone. In cores 4 to 7 the glacial zones are relatively thin and 

are spaced at approximately equal intervals; between the third 

and fourth glacial zones (in descending order) is the lower volcanic 

ash. East of the mid-Atlantic ridge only the uppermost glacial

zone has been identified. Other glacial marine deposits are 

recognizable but their correlation is less certain.

Three interpretations are offered as possible explanations of 

the four glacial marine zones. The first is that each glacial 

marine zone represents a distinct glacial stage of the Pleistocene 

and that each zone of foraminiferal marl separating two glacial 

marine zones represents an interglacial stage. This interpretation seems least probable of the three. The second interpretation 

is that the upper two glacial marine zones and the intervening 

sediment may correspond to the bipartite Wisconsin stage, 

whereas the lower two represent distinct glacial stages of the 

Pleistocene separated from each other and from the zone representing the Wisconsin stage by sediments that represent interglacial epochs no greater in length than postglacial time. This 

interpretation seems to imply too short a time for most of the 

Pleistocene epoch. The third interpretation, which is favored 

by the authors, is that each of the four glacial marine zones 

represents only a substage of the Wisconsin stage. This implies 

that the North Atlantic at approximately 50° north latitude for 

comparatively long periods of time alternately contained an 

abundance of drift ice and then was quite, or nearly, free of ice, 

while on land a continental ice sheet persisted, though it alternately waned and grew.

In the four cores in which the postglacial sediments are 

thickest the pelagic Foraminifera, according to Cushman and 

Henbest, reveal an interesting condition. These organisms 

indicate that during the middle part of the postglacial interval 

the temperature of the surface water in that part of the North 

Atlantic was somewhat higher than prevails today.

On the assumptions that the top of the uppermost glacial 

marine zone represents the beginning of the postglacial epoch as 

defined by Antevs, and that this was probably as much as 9,000 

years ago, the postglacial sediment in these cores accumulated 

at a rate of about 1 centimeter in 265 years; but, because the sea 

probably cleared of detritus-laden drift ice long before the land 

in the same latitude was cleared of the retreating continental 

ice sheet, the average rate of accumulation may have been as 

low as 1 centimeter in 500 years.

Coarse-grained sediment on the tops of ridges and fine-grained 

sediment in the deeper basins indicate that currents move across 

these ridges with sufficient velocity to winnow out the finer 

particles and sweep them into deeper basins beyond.

The fact that the glass shards in the volcanic ash zones have 

been reworked and distributed without any gradation in size 

through many centimeters of the overlying sediments leads us 

to believe that mud-'feeding animals are continually working over 

these shards and other particles of sand and silt so that they are 

redistributed at successively higher levels. The shards and other 

particles may also be reworked by gentle bottom currents that 

move the material from mounds and ridges on the sea floor and 

drift it about over the adjacent flatter areas.

Several layers in the cores are sharply set off by the coarser 

grain size of the sediment or by a regular gradation in grain size 

from coarsest at the base to fine at the top. These may be a 

result of submarine slumping.

The term globigerina ooze is used loosely in this report to 

designate sediment, half or more than half of which, by weight, 

consists of Foraminifera. This usage accords more closely with

VII
VIII SUMMARY OF THE REPORT

the usage adopted by Correns in the Meteor reports than with 

the usage of Murray and Chumley in the Challenger reports, 

which was based solely on the carbonate content. Limy muds 

containing a lesser but still conspicuous number of Foraminifera 

are referred to as foraminiferal marl. The carbonate content 

of the globigerina ooze in these cores ranges from 46.6 to 90.3 

percent and averages 68.2 percent. In 191 samples representing 

all the lithologic types, the carbonate content ranges from 10.0 

to 90.3 percent and averages 41.3 percent. Coccoliths are 

abundant in many parts of the cores, but by reason of their small 

size they rarely make up as much as 10 percent of the sediment. 

Ptcropods are rather numerous in parts of the cores taken on the 

mid-Atlantic ridge and on the continental slope off the Irish 

coast.

Most of the calcium carbonate in these sediments consists of 

the tests and comminuted fragments of calcareous organisms. 

The finest particles of carbonate are of indeterminate origin, but 

their irregular shape and range in size suggest that they are 

largely the finest debris of the comminuted organisms rather 

than a chemical precipitate. Clusters or rosettes of calcium 

carbonate crystals were found in many samples, but they are not 

abundant. They evidently formed in the mud on the sea floor.

No conclusive evidence of an increase in magnesium carbonate 

with depth was found, though some of the data suggest it. The 

magnesium carbonate is somewhat more abundant in the glacial 

marine zones than elsewhere, but its concentration in those zones 

is probably accounted for by the presence of clastic grains and 

pebbles of dolomite.

Diatom frustules, radiolarian skeletons, and sponge spicules 

are the most common siliceous organic remains found in the 

cores, and these generally form less than 1 percent of the sediment. One notable exception is the sediment in the middle part 

of core 9, just east of the mid-Atlantic ridge, which contains 50 

percent or more of diatoms.

Ellipsoidal and elongate or cylindrical pellets that appear to 

be fecal pellets are plentiful in the mud at the tops of cores 10 

and 12, taken in the eastern part of the North Atlantic, but 

were not found elsewhere. No attempt was made to identify 

them further.

The sand-size material showed no marked variation in the 

mineral composition of the clastic grains at different horizons 

within individual cores and no conspicuous lateral variation 

from core to core. The mineral grains in the sand-size portions 

were not separated into light and heavy fractions, but simple 

inspection showed that grains of the heavy minerals are somewhat more common in the glacial marine deposits than elsewhere. Well-rounded sand grains are sparsely scattered through 

all the cores, but they are rather more plentiful in the glacial 

marine zones. These grains, which range in diameter from about 

0.1 to 1.0 millimeter and average 0.5 millimeter, have more or 

less frosted surfaces. They may have been derived from the 

reworking of glacial marine deposits or they may have been 

rafted by seaweeds. Little was done with the clay minerals 

other than to note that most of them have the optical properties 

of the beidellite or hydrous mica groups.

Six samples were tested with a 10-inch spectograph, which 

revealed the presence of appreciable amounts of barium and 

somewhat less of boron in each sample. All the samples gave 

negative tests for antimony, beryllium, bismuth, cadmium, germanium, lead, silver, tin, and zinc.

The original porosity of several samples in core 3 was calculated from the porosity of the dried samples. The original 

porosity plotted against depth in the core seems to indicate that 

fine-grained blue muds buried to a depth of 2 or 3 meters in the 

ocean floor are appreciably compacted.

Partial mechanical analyses of nearly 200 samples were made 

and plotted, but only four complete mechanical analyses were

made. The complete analyses were made by the sedimentation 

method and include four distinctive types of sediment.

Pumiceous fragments and smaller shards of basaltic volcanic 

glass (index of refraction near 1.60) are scattered throughout all 

the cores, but are somewhat more common east of the mid-Atlantic ridge than west of it. Unlike the alkalic volcanic ash it 

shows no conspicuous concentration in zones. Most of the basaltic glass and pumice has a thin surface alteration film of palagonite. The films are thickest on fragments in cores taken from 

ridges where oxygen-bearing waters had free access to the sediments. Two varieties of palagonite are recognized.

Core 11 represents only 34 centimeters of the sea floor because 

the core bit encountered deeply altered olivine basalt. About 

15 centimeters of globigerina ooze rests on and within irregular 

cavities of the upper surface of a mass of clay that is apparently 

altered basalt. This clay is impregnated with manganese and 

contains nodular lumps of altered basalt. Part of the basalt 

near the base of the core is less altered. The clay contains scattered grains of sand and foraminiferal shells in which the original 

calcium carbonate has been replaced by a zeolite resembling phillipsite. This core may have penetrated the upper, deeply altered 

part of a submarine lava flow, but the evidence is not conclusive.

Core 10 contains two rather thick beds of distinctive clayey 

mud. About half of this mud is a beidellite or hydrous mica 

type of clay and the other half is made up of silt-size particles of 

basaltic glass, magnetite, augite, and calcic plagioclase. It 

contains very little common clastic material and exceedingly 

few Foraminifera. The composition and texture suggest that 

this mud was derived largely from a submarine volcanic eruption 

that threw into suspension clay particles perhaps partly from the 

normal sediment and from deeply altered basalt. A complete 

chemical analysis of this mud is given.

Foraminifera..—From these cores 184 samples representing 

every lithologic zone were examined for calcareous fossils. All 

but five samples contained Foraminifera. As in existing oceans 

deeper than several hundred meters, pelagic Foraminifera greatly 

outnumber the bottom-dwelling forms, though in variety of form 

and in number of genera and species the bottom forms greatly 

exceed the pelagic. Several zones of relatively pure globigerina 

ooze were found, and many in which the ooze was clayey or sandy. 

Though variations in temperature were reflected by faunal 

changes, the general bathymetric facies of the faunas appear to be 

rather uniform throughout each core. The bottom faunas are 

least varied and prolific in cores from the deepest water, whereas 

in cores from the shallowest water they are by far the most 

varied and prolific. Cores from intermediate depths contain 

faunas of intermediate bathymetric facies. These relations to 

depth are, in general, characteristic also of faunas in the existing 

oceans. A few scattered specimens of Elphidium or Elphidiella 

were found. These genera thrive in shallow water, but in these 

cores the shells are so rare, so erratically distributed, and in some 

so poorly preserved that it seems probable they were rafted in by 

seaweeds or ice and therefore have no significance as indicators of 

depth. No species peculiar to the Miocene or Pliocene were 

found. It appears, therefore, that all the sediments penetrated 

by the cores are younger than Pliocene. Alternation of faunas 

that are characteristic of the warm and cold climates of the 

present day indicates great climatic changes during the time 

represented by these cores. The foraminiferal facies characteristic of cold and warm climates correlate with the alternating 

sequence of glacial-marine and warmer-water sediments indicated 

by the lithology. This correlation suggests that all the sediments in these cores are of Recent and Late Pleistocene age.

Diatomaceae.—Fifty-two species and varieties of diatoms were 

found in these cores. A large percentage of the species are neritic, 

warm-water forms that are foreign to the region today. Several
SUMMARY OF THE REPORT IX

alternations of warm-water and cold-water diatom floras occur 

in most of the cores, but their position in the cores is not in 

accord with the alternations of temperature inferred from lithology and foraminiferal facies. It is suggested that this disagreement may be due to the much longer settling time of the diatoms 

and that allowance should be made for it. The time equivalent 

of this difference of phase, as calculated from the vertical displacement necessary for the best approximation to agreement 

between the foraminiferal and lithologic data on the one hand 

and the diatom data on the other is of the order of 23,000 years. 

This figure appears absurdly high and a figure of several hundred 

years, based on extrapolation of experimentally timed settling 

in a relatively small vessel, is considered more reasonable. The 

action of cold and warm currents, some surficial and some deep 

seated, is suggested as the possible cause of the apparently erratic 

distribution of the diatoms. The possibility that the phase difference of 23,000 years mentioned above is related to shifts of 

ocean currents caused by advances and recessions of drift ice is 

offered as a speculation. Of 52 species and varieties illustrated. 

2 species and 1 variety are described as new.

Ostracoda.—In preparing a series of samples from the cores for 

the study of the Foraminifera about 175 specimens of Ostracoda 

were f^und. These belong to 13 genera and 27 species, all living 

forms, though 12 of the species are known also as fossils. Most 

of the ostracodes were found in three cores that were taken in 

the shallowest water (1,280 to 3,230 meters). One of these cores 

(No. 8) was from the top of the mid-Atlantic ridge and the other 

two (Nos. 12 and 13) were from the continental slope southwest 

of Ireland. In the cores from deeper water (3,250 to 4,820 

meters) ostracodes were scattered very sparsely Like most 

marine ostracodes, all the species found in the cores are bottom 

dwellers. Most of the species are decidedly cold-water forms 

that are found in tropical waters only at great depth, where the 

temperature is near freezing. Northern forms predominate; only 

2 of the species have not previously been known from northern 

waters, and 10 species are definitely Arctic forms. A few species 

that have a wider temperature range live not only in cold waters 

but also in the deep warm water of the Mediterranean.

The predominance of distinctly cold-water ostracodes and the 

prevalence of Arctic forms suggest that the temperature of the 

water in this part of the North Atlantic was formerly somewhat 

lower. But, as might be expected from the fact that all the 

species in these cores are bottom dwellers, their distribution in 

the cores shows no evident relationship to the cold and warm 

zones indicated by the composition and texture of the sediments 

and by the pelagic Foraminifera.

Mollusca.—The mollusks recovered from these cores can be 

divided into two groups, the pteropods and the other gastropods 

and pelecypods. The pteropods are by far the more numerous. 

All the specimens of the pelecypods and gastropods, other than 

pteropods, are representatives of deep-water species that are now 

living in the same boreal or cold-temperate waters. Also, the 

fragments that could not be identified specifically belong to forms 

that have congeners now living in these waters. The fauna of 

these cores, even that taken from the lower parts of the cores, 

shows no appreciable difference from that now living in the same 

localities. Among these mollusks no evidence of shallower or 

considerably deeper water is demonstrable. Molluscan remains, 

other than those of pteropods, are too scarce to attempt to 

differentiate cold- and warm-water facies, as was done with the 

foraminiferal faunas.

The Pteropoda, which are far more abundant in the cores than 

the other mollusks, belong to two genera and three species. One 

of the species is new. The geographic distribution of the pteropods is limited more by the temperature of the surface water 

than by any other factor. Nevertheless, as one species is cosmopolitan, one boreal, and doe a new species thought to be the

northern analogue of a more southern species, and as all three 

species occur together, they have no significance for differentiating cold- and warm-water facies. These organisms are pelagic 

and their shells have a rather wide distribution, but, as they are 

found on the sea floor at depths ranging from 247 to 3,750 meters, 

they are of little aid as indicators of depth of the ocean at the 

time these deposits were laid down.

Echinodermata.—The remains of 9 species of Echinodermata 

were found in the cores. These include 1 ophiuroid, 7 echinoids, 

and 1 crinoid. No remains of asteroids were found. All the 

echinoderms found belong to species now living in that part, or 

adjacent parts, of the North Atlantic. Echinoderm remains are 

rather uniformly distributed among the cores, but they are most 

numerous in core 8, which was taken in 1,280 meters of water 

on the crest of the mid-Atlantic ridge. By far the commonest 

species is Pourtalesia miranda, remains of which were found in 

nearly two-thirds of the 82 echinoderm-bearing samples and in 

all the cores except 8 and 11.

Because the association of species in the cores is closely 

similar to the association of living species in that part of the 

North Atlantic and because the association of species within each 

core is independent of the distance below the top of the core it 

appears that neither the distribution nor the composition of the 

echinoderm fauna has changed significantly during the interval 

represented by these cores. No evident relationship was found 

between the distribution of the various species of echinoderms 

and the cold- and warm-water facies of the sediments indicated 

by both the Foraminifera and the lithology.

Miscellaneous fossils and significance of faunal distribution.— 

The principal fossil groups represented in the cores, listed in 

order of abundance, are foraminifers, diatoms, echinoids, siliceous 

sponges, radiolarians, ophiuroids (spines and plates), ostracodes, 

and pteropods. Remains of barnacles, brachiopods, pelecypods, 

holothuroids, bryozoans, gastropods, and teleost fishes (otoliths) 

were also found, but all these are rare. The foraminifers, diatoms, ostracodes, echinoderms, pelecypods, and gastropods were 

studied separately by specialists. The other groups are briefly 

noted and illustrated for the sake of the record. The most 

varied and prolific faunas were found in the three cores that 

were taken from the shallowest water and the least varied and 

least prolific were found in those from the deepest water. The 

bottom-living faunas throughout each core have a broadly similar bathymetric facies, and the bathymetric facies of each core 

appears to correspond to that of the fauna now inhabiting that 

locality. Faunas having the characteristics of very shallowwater marine faunas are either absent or, if present, are so rare 

and erratically distributed that they appear to be foreign in 

origin rather than indigenous. Ostracodes and pteropods are 

locally abundant in the cores from the shallower water, but are 

absent or rare at all horizons in those from the deeper water. 

The distribution and bathymetric facies of the faunas weigh 

heavily against the hypothesis of extreme changes in ocean 

level during the later part of the Pleistocene.

Organic matter content.—The content of organic matter, as 

determined from 123 samples, ranges from 0.1 to 1.0 percent of 

the total weight of the sec iments, and the average is about 0.5 

percent. As in near-shore sediments, it is influenced by the 

configuration of the sea bottom. It is small on ridges and large 

in the deeps. It is particularly large in the sediments at the 

base of the east slopes of ridges, owing in part, probably, to 

material washed from the vicinity of the ridges by eastwardsweeping ocean currents. The organic matter content of the 

upper layers of the sediments in the abyssal deeps is greater 

for a few hundred miles east of the mid-Atlantic ridge than it 

is for a similar distance west of the ridge. The organic content 

does not vary consistently with depth except in core three, 

taken at the foot of the continental slope east of the Grand

282255-41-
X SUMMARY OF THE REPORT

Banks, where it seems to decrease about 25 percent in the first 

1.5 meters. The organic matter content of the sediments tends 

to be greater in the warm zones, than in the cold zones, and in 

general it is slightly greater in sediments which, according to 

Cushman's determination of the Foraminifera, were probably 

deposited in areas in which the surface water was relatively 

warm. The organic content is rather closely related to the 

texture, and increases with increasing fineness of the sediments. 

The rate of deposition of organic matter is greater east of the 

mid-Atlantic ridge than west of it, presumably owing in part 

to a greater supply of plankton and in part to a slower rate of 

decomposition of the organic matter after it is laid down in the 

sediments. The slower rate of decomposition within the sediments is inferred from the greater state of reduction of the 

sediments, which is indicated by the nitrogen-reduction ratio. 

The nitrogen-reduction ratio suggests a slight increase in state 

of reduction with increasing depth of burial in the upper part 

of the deposits, but indicates no significant change in the lower 

part. The percentage of organic content tends to increase as 

the percentage of Foraminifera in the sediments decreases, but 

it shows no relationship to the calcium-carbonate content.

Selenium content and chemical analyses.—As a part of a comprehensive investigation of the distribution of selenium in marine

sediments and soils derived from them complete fusion analyses 

were made of 20 samples from the suite of 11 cores. These 

samples were taken from the tops of the cores and at intervals of 

approximately 1 and 2 meters below the top. In addition, 1 

core taken on the continental shelf off Ocean City, Md., and 3 

cores from the Bartlett Deep were sampled and analyzed, making 

a total of 31 analyses. The results of the analyses include all 

the normal analytical data obtained in a so-called complete soil 

analysis by the fusion method, and, in addition, determinations 

of organic matter, nitrogen, chlorine (in all but 12 analyses), 

hygroscopic water, and selenium. All the samples were analyzed 

with the entrained sea salts. The core from the continental 

shelf off Ocean City contained the most selenium—at the top 

0.6 part per million, at 1 meter 1.0, and at 2 meters 2.0 parts per 

million. The samples from the North Atlantic cores showed a 

selenium content ranging from 0.06 to 0.8 part per million. Of 

the samples from the Bartlett Deep one contained 0.2 part per 

million of selenium, but all the others contained less than 0.08 

part per million. No evidence was found of a relation between 

the selenium content and volcanic activity.

The silica-sesquioxide and silica-alumina ratios are tabulated 

and their significance as means of comparing the analyses is 

discussed.
FOREWORD

By C. S. PIGGOT

During the last cruise (1927-29) of the nonmagnetic 

ship Carnegie of the Department of Terrestrial Magnetism of the Carnegie Institution of Washington a' 

number of samples of the deep ocean bottom were 

obtained by means of • the telegraph snapper. The 

Geophysical Laboratory determined the radium content 

of these samples and found that they contained a concentration of radium 2 as astonishingly high as that 

reported by Joly 3 and Pettersson 4 from similar samples 

taken by the Challenger and Princess Alice II. This 

high radium concentration in the surface layer of the 

ocean bottom, which constitutes 72 percent of the surface of the globe, raises questions of great significance 

to both oceanography and geophysics. An obvious 

question is whether radium in so high a concentration is 

present down through all deep-sea sediments or only 

at the surface.6 If the first hypothesis is correct it 

indicates the presence of uranium throughout the sediments, whereas the second indicates the existence of 

radium itself, presumably separated out from the sea 

water. The study of this question requires samples of a 

type analogous to the cores so extensively used in subsurface exploration on land. Inquiries among oceanographic organizations established the fact that although 

some cores a meter or more in length had been obtained 

from relatively shallow water, many of them were much 

distorted by the time they reached the laboratory, and 

none as long as 1 meter had been obtained from a depth 

of 4,000 meters or more.6 Those engaged in such research 

emphasized the need of apparatus capable of obtaining 

undistorted cores from great depths. In 1933 the 

Council of the Geological Society of America approved a 

grant for the development of such apparatus.7 Fortunately, cooperation was obtained from several special

1 Geophysical Laboratory, Carnegie Institution of Washington.

* Piggot, C. S., Radium content of ocean-bottom sediments: Am. Jour. Sci., 5th 

ser., vol. 25, pp. 229-238, 1933.

3 Joly, J., On the radium content of deep-sea sediments: Philos. Mag., vol. 16, pp. 

190-197,1908.

1 Pettersson, Hans, Teneur en radium des depots de mer profonde: Resultats de 

Campagnes Scientiflques par Albert I« Prince Souverain de Monaco, vol. 81, 1930.

« Piggot, C. S., op. cit., p. 233.

«Since these inquiries were made D. Wolansky has published her review in the 

Geologische Rundschau (Band 24, Heft 6, p. 399,1933), in which she refers to the work 

of A. D Archanguelsky in the Black Sea (Soc. Naturalistes Moscow Bull., new ser., 

vol. 35, pp. 264-281,1927). Wolansky mentions cores 3 to 4 meters long from depths 

of 2,237 meters See also Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 

1925-27, Band 3, Teil 2, Lief. 1, pp. 4-28,1935.

7 Piggot, C. S., Apparatus to secure core samples from the ocean bottom: Qeol. 

Soc. America Bull., vol. 47, pp. 676-684,1936.

agencies, particularly the Burnside Laboratory of the 

E. I. du Pont de Nemours, whose ballistics expert, Dr. 

B. H. Mackey, offered fundamental suggestions and 

made many essential calculations and tests; also the 

United States Bureau of Lighthouses, from whose lightship tender, the S. S. Orchid, many experimental soundings were made. Several forms of the apparatus were 

developed and tested, and in August 1936 14 satisfactory 

cores were obtained from the canyons in the continental 

shelf off New Jersey, Delaware, and Maryland, and 

another from the ocean floor below 2,500 meters of 

water. 8 This first deep-sea test was made possible by 

the cooperation of the Woods Hole Oceanographic 

Institution and was carried out in connection with an 

investigation of the submarine canyons by H. C. Stetson 

of that institution. This test demonstrated the feasibility of the apparatus as built but suggested some 

minor changes in design. These were incorporated in 

another apparatus, which was put aboard the cable ship 

Lord Kelvin at Halifax, Nova Scotia. Through the 

courtesy of Mr. Newman Carlton, Chairman of the 

Board of Directors of the Western Union Telegraph Co., 

the Carnegie Institution of Washington was invited to 

have a member of its staff accompany the Lord Kelvin 

while that ship was engaged in making repairs to the 

North Atlantic cables, in order to test the apparatus in 

deep water. This offer was gladly accepted, and in 

May and June of 1936 I was on board the Lord Kelvin 

with the apparatus.

Because of the personal interest and cooperation of 

the commanding officer, Lt. Com dr. Bredin Delap, 

Royal Navy, retired, the undertaking was more successful than had been anticipated, and a suite of 11 

excellent cores was obtained, extending from the Grand 

Banks of Newfoundland to the continental shelf southwest of Ireland.

All but two of these cores (Nos. 8 and 11) are more 

than 2.43 meters (8 feet) long, and all contain ample 

material for study. Of the two short cores, No. 8 was 

taken from the top of the Faraday Hills, as that part 

of the mid-Atlantic ridge is known, where the material 

is closely packed and more sandy and consequently 

more resistant; No. 11 came from a locality where the

' Cushman, J. A., Henbest, L. Q., and Lohman, K. E., Notes on a core sample from 

the Atlantic Ocean bottom southeast of New York City: Qeol. Soc. America Bull., 

vol. 48, pp. 1297-1306, 1937.

XI
XII FOREWORD

apparatus apparently landed on volcanic rock that may 

be part of a submarine lava flow. Soundings at the 

localities where the cores were taken show depths ranging from 1,280 meters at the top of the Faraday Hills to 

4,820 meters in the deep water between the mid-Atlantic 

ridge and the continental shelf.

The thorough test made possible by the interested 

cooperation of everyone on board the Lord Kelvin fully 

demonstrated the capacity of the apparatus and produced material from strata of oceanic sediments deeper 

than have ever before been available.

In order that this pioneer material might be examined to the best advantage and an adequate estimate 

made of the potentialities of cores of this type, a group of 

investigators representing various fields of science was 

invited to examine them. Efforts have been made to 

arrange the sequence of these investigations in such a 

way that the maximum information may be obtained 

with the minimum destruction of the samples.

The cores are now at the Geophysical Laboratory of 

the Carnegie Institution of Washington, where they and 

others that may be obtained by this laboratory will be 

held available for further research.
GENERAL INTRODUCTION

By W. H. BKADLEY

SIGNIFICANCE OF THE INVESTIGATION

The long cores of deep-sea sediment considered in 

this report represent a longer span of the earth's late 

geologic history, as recorded in abyssal sediments, than 

has been heretofore accessible. In a measure, therefore, this study has been exploratory. Because of that exploratory aspect we have not only presented the observations but also have deliberately speculated upon various 

possible interpretations of the features observed in the 

cores and upon their relations with one another. Because the cores are few in number and widely spaced, 

we offer many of the interpretations not as definite 

conclusions but rather as suggestions to be tested by 

whatever coring may be done in the future in that part 

of the North Atlantic.

From this investigation it appears that glacial marine 

deposits may prove to be sensitive indicators of the climatic changes that caused the growth and decay of 

continental ice sheets during the Pleistocene. In particular, it seems that the glacial marine record may 

throw light on the climatic fluctuations that determined substages of the Pleistocene. The marine 

record was the result of a continuously operating series 

of causes such that the deposits of each glacial substage 

were separated from one another by the deposits of the 

intervening warmer substage. The record of each 

substage has remained intact and was not obliterated 

by readvances of the ice. As the equatorward extent 

of the glacial marine deposits implies a corresponding 

expansion of continental ice sheets, the extent of the 

deposits may be used as a measure of the intensity of 

the climatic changes, and their thickness may be used 

as a rough indicator of the duration of glacial substages. 

Similarly, the thickness and poleward extent of tongues 

of nonglacial sediment—the foraminiferal marl—are 

measures of deglaciation. The areal extent of these 

tongues of sediment can be determined by additional 

cores taken at properly located stations.

When the glacial marine record is more fully known 

it should provide a basis for correlating the Pleistocene 

history of Europe and North America.

Cores taken along the meridians in series extending 

from the Arctic regions into the tropical parts of the 

Atlantic should make it possible to map the southern 

limits of pack ice in the sea during successive glacial 

maxima, at least for the later part of the Pleistocene.

As the pelagic Foraminifera in these abyssal sediments 

are reliable indicators of surface-water temperatures in 

the Recent and Pleistocene epochs, it should be possible 

to trace southward into the tropics layers or beds of 

foraminiferal ooze that are the tune equivalents of 

glacial marine zones. Such layers of foraminiferal ooze 

could then be correlated with the layer of globigerina 

ooze in the tropics that Schott 9 identified as a relatively cold-water deposit that probably represents the 

last glacial epoch of the Pleistocene.

The study of climatology as well as geology may be 

advanced by the information to be derived from long 

sea-bottom cores. Significant evidence bearing on postglacial climatic changes may be obtained from minutely 

detailed study of the Foraminifera in cores taken in 

parts of the ocean where postglacial sedimentation has 

been comparatively rapid, as, for example, near the 

seaward edge of the blue-mud zone. On the assumption that such sediment accumulates at an essentially 

uniform rate, climatic fluctuations may be located approximately in tune within the postglacial interval and 

may be correlated from place to place along the ocean 

margins from the Arctic to temperate or even tropical 

latitudes and perhaps also from continent to continent.

Archeology, also, might profit from the knowledge 

of a relatively timed and correlated sequence of climatic changes, for such changes may well ha\e made a 

significant impress on the habits and migrations of 

peoples, particularly those that dwelt in regions where 

small changes in either temperature or rainfall were 

critical. As I have pointed out in an earlier paper, 10 

students of archeology and early history, particularly in 

the Mediterranean region, might profit much from 

detailed studies of long cores of the sediment in the 

deep basins of the Mediterranean. In cores from that 

sea, as elsewhere, changes in the foraminiferal faunas 

would indicate climatic changes, and the sediments 

would yield, in addition,'evidence of volcanic eruptions 

and earthquakes. The time when the Sahara became 

a desert should also be recorded in the Mediterranean 

sediments by wind-blown sand. Such a change might 

conceivably be integrated with the wealth of archeo-

• Schott, W., Die Foraminiferen in dem Squatorialen Teil des Atlantischen Ozeans: 

Wiss. Ergeb. Deutschen Atlantischen Exped. Meteor, 1925-27, Band 3, Teil 3, Lief. 1, 

pp. 120-128, 1935.

10 Bradley, W. H., Mediterranean sediments and Pleistocene sea levels: Science 

new ser., vol. 88, pp. 376-379, 1938.

XIII
XIV GENERAL INTRODUCTION

logical records of the region, and the later volcanic 

eruptions and earthquakes might be correlated with 

early history.

Some of the problems sketched so briefly here are 

touched upon in the several chapters of this report, 

but most of them must be left for future investigators. 

Nevertheless, methods by which such problems may 

be attacked are described and discussed at considerable 

length, particularly in the chapters on "Lithology and 

geologic interpretations" and "Foraminifera."

LOCATION OF THE CORE STATIONS

The cores were taken along a slightly irregular line 

between the easternmost part of the Newfoundland 

Banks and the banks off the southwest coast of Ireland, 

as shown in plate 1. Each core obtained by the Piggot 

coring device is numbered to correspond with the station 

number of the cable ship Lord Kel/in. Stations 1 and 

2 were trial stations at which preliminary tests were 

made to familiarize the crew with the apparatus, and 

no cores were preserved. The 11 cores studied are 

numbered consecutively, 3 to 13. The relation between

M. N. Bramlette, J. A. Cushman, L. G. Henbest, K. E 

LohmaD, and P. D. Trask. As the biologic phase of 

the work progressed it became evident that other 

organisms than the foraminifers and diatoms should be 

studied. Accordingly Mr. Henbest invited Dr. Willis 

L. Tressler, of the University of Buffalo, to examine the 

ostracodes, Dr. Austin H. Clark of the United States 

National Msueum, to examine the echinoderms, and 

Dr. Harald A. Rehder, also of the United States 

National Museum, to examine the mollusks.

The organic matter content of the sediments was 

studied by Mr. Trask in collaboration with Messrs. 

H. Whitman Patnode, Jesse LeRoy Stimson, and John 

R. Gay, all members of the American Petroleum 

Institute.

As part of a comprehensive research project on the 

distribution of selenium in marine sediments and the 

soils derived from them Dr. H. G. Byers and Mr. Glen 

Edgington, of the Bureau of Chemistry and Soils, 

United States Department of Agriculture, made complete chemical analyses of 20 samples from these deepsea cores. These analyses, together with analyses of

w

ST JOHNS 

NEWFOUNDLAND 

Meters

MID-ATLANTIC RIDGE 

" FARADAY HILLS" 

6 789

E.

LANDS END 

ENGLAND

FIGURE I.—Profile across the North Atlantic Ocean along the line of the numbered core stations shown on plate I.

the core stations and the submarine topography is 

shown in figure 1, which is a profile along the dashed 

line in plate 1 that connects the stations and extends 

from St. Johns, Newfoundland, to Lands End, England. 11

TABLE 1.—Geographic location, length of the cores, and depth of 

the water from which they were taken

Core number

3.. ...... ........... ... ..

4.. ........ ....................... ...

5........................... ...... ..

6

7....................................

8 .

9

10 .......... .... . ..

11 .-.... — _--.__ ....... .

12...................................

13 .. — ... — ..-......... . .

Depth 

of water 

(meters)

4,700

4,820

4, 125

3,250

3,745

4,190

3,230

1,955

Length 

of core 

(meters)

2.81

2.71

2.82

2.90

2.62

2.97

.34

2.21

Lat. N.

46°oroo"

48°38'00"

49°32'00"

4Q°^A'fln"

iOOOQ/fW/

4Q0l?7'ftft"

Long. W.

3^°^4'3n"

36°01'00"

29°21'00"

Qsjo^ii'nfl"

28°29'00"

17°09'00"

looq^'n/y

lOOog'AA"

PERSONNEL AND COMPOSITION OF THE REPORT

At the request of Dr. C. S. Piggot, of the Geophysical 

Laboratory of the Carnegie Institution of Washington, 

the following six members of the United States Geological Survey undertook a systematic study of the 11 

deep-sea cores from the North Atlantic: W. H. Bradley,

11 Data for plate 1 and figure 1 were taken from International Hydrographic Bureau, 

Carte Generate Bathymetrique des Oceans, 3d ed., sheets A-l and B-l, copies of 

which were furnished by the U. S Hydrographic Office.

samples from several other deep-sea cores and a discussion of the occurrence of selenium, are included in 

the chapter on "Selenium content and chemical

analyses."

METHODS OF SAMPLING AND EXAMINATION

The Piggot coring device l2 takes the cores in brass 

sampling tubes that have an inside diameter of 4.9 cm. 

As soon as a core is taken, the tube is cut off at the 

approximate length of the core and sealed. The cores 

here discussed were opened under Dr. Piggot's direction 

at the Geophysical Laboratory of the Carnegie Institution of Washington. A longitudinal cut was made 

along one side of each brass core barrel by means of a 

milling cutter so adjusted that it did not cut quite 

through the wall of the tube. The thin strip remaining 

was then ripped out without letting brass chips get 

into the core. After allowing the mud cores to dry 

somewhat, but not enough to shrink away from the 

tube walls, the cores and core barrels were cut in half 

longitudinally with a metal-cutting band saw. In this 

cutting, the milled slot was held uppermost so that the 

saw cut only the lower wall of the core barrel and 

threw the cuttings downward, away from the core.

'« Piggot, C. S., Apparatus to secure core samples from the ocean bottom: Qeol. 

Soc. America Bull, vol. 47, pp. 675-684.1936.
GEOLOGICAL SURVEY

60° (Follows p. XV) PROFESSIONAL PAPER 196 PLATE 1 10°

40°

20 IOC

Sea level to 

500 meters

500-2,000 

meters

2,000-4,000 

meters

4,000-6,000+ 

meters

BATHYMETRIC CHART OF A PART OF THE NORTH ATLANTIC OCEAN.

The numbered circles indicate the core stations. The dashed line connecting them is the line of the profile shown in figure 1. The light dotted line along the coasts is the 200-meter depth contour. The usual limit of drift ice is shown by the heavy dotted line. The small triangles indicate the position of icebergs reported far beyond their normal range during the period January 1900 to July 1916, according to information compiled by J. T. Jenkins (A Textbook of Oceanography, fig. 14, London, Constable & Co., 1921).

U.S. GOVERNMENT PRINTING OFFICE : 1940—0.228324


2 PLATE 196 PAPER PROFESSIONAL SURVEY GEOLOGICAL 

CORES. AIR-DRIED THE OF SECTIONS LONGITUDINAL 

Washington. of Institution Carnegie Laboratory, Geophysical by Photograph cut. not was itself core the but 11, core from removed was barrel core the of Half 
GENERAL INTRODUCTION XV

Each half core then remained undisturbed in its half 

cylinder cradle of brass core barrel. (See pi. 2.)

As several months elapsed between the time the cores 

were opened and the time this investigation began, the 

mud had dried thoroughly when Mr. K. E. Lohman 

took a succession of overlapping photographs of each 

core, about one fifth natural size. These photographs 

were then assembled as a key chart upon which were 

marked the parts from which samples for all phases of 

the investigation were taken. The dried segments of 

mud shifted somewhat from their original places each 

time samples were removed, though care was taken

to see that during sampling the segments kept their 

original order and orientation. By reference to this 

photographic key the findings of all the investigators 

have been correlated.

Most of the material was hard enough to be sawed 

into blocks with a hack saw, but a few of the most 

friable parts were sampled with small channel-shaped 

scoops of sheet metal after the loose material on the 

surface had been brushed away.

Samples for all phases of this investigation were 

taken from only one half of each core, the other half 

being held intact in the Geophysical Laboratory.

GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES 

BETWEEN NEWFOUNDLAND AND IRELAND

PART 4. OSTEAOODA

By WILLIS L. TRESSLER l

INTRODUCTION

The material described in this report was obtained 

in 1936 in the North Atlantic Ocean with the Piggot 

deep-sea core sampler 2 on board the Western Union 

cable ship Lord Kelvin. While looking over the samples 

for Foraminifera, L. G. Henbest of the Federal Geological Survey, found a few ostracodes, which were picked 

out and sent to me for identification. Some 175 ostracodes belonging to 13 genera and 27 species were 

identified and are discussed in the following pages. 

Photographs of specimens of all but two of the species 

were made by Mr. Henbest and are reproduced here as 

plate 19, figures 1 to 27. I am greatly indebted to 

Mr. Henbest and to W. H. Bradley, also of the 

Geological Survey, for much helpful criticism and 

assistance. Because few ostracodes have previously 

been described from marine core samples, this material 

is of particular interest.

ECOLOGY OF THE OSTRACODES

In his treatise on sedimentation, Twenhofel 3 says of 

the planktonic Arthropoda (phyllopods, copepods, and 

ostracodes) that "As they belong to the plankton, their 

distribution at all times has been independent of the 

character of the bottom, and they lend little to evaluation of conditions of the environment." This statement is certainly correct for the first two groups of 

planktonic Arthropoda, but it is not entirely true for 

the ostracodes.

The great majority of ostracodes are strictly bottomdwelling organisms; indeed many are entirely incapable 

of swimming. A brief review of the various groups of 

the Ostracoda will bear this out. The suborder Myodocopa includes both pelagic and benthonic forms. In 

some genera the females are confined to the bottom 

although the males are active swimmers and may be 

taken at the surface. The family Conchoecidae is entirely pelagic. The suborder Platycopa contains strictly

' Zoology Department, University of Maryland, College Park, Md. 

* Piggot, O. S., Apparatus to secure core samples from the ocean bottom: GeoJ, 

Soc. America Bull., vol. 47, pp. 675-684,1936. 

3 Twenhofel, W. H., Treatise on sedimentation, 2d ed., p. 182,1933.

benthonic forms, which are confined to the deeper parts 

of the ocean. The Cladocopa are good swimmers, but 

most of them live on the bottom. Polycope orbicularis, 

the only representative of this suborder found in the 

core samples, swims along the bottom at depths of 

10 to 35 meters. The largest of the suborders, 

the Podocopa, contains representatives of both pelagic 

and benthonic forms. Of the Cypridae, one genus, 

Pontocypris, contains active swimmers, but these forms 

rarely leave the bottom. The other marine genera are 

either poor swimmers and never leave the bottom or 

are without swimming organs. Macrocypris, Bythocypris, and Bairdia, genera which were found in the 

core samples, are distinctly bottom-dwelling forms. The 

family Cytheridae, to which all except four of the genera 

found in the core samples belong, is entirely restricted 

to the bottom. All 13 genera from the core samples, 

therefore, are known to be bottom-living forms. Although some forms are widely distributed in the oceans, 

many have a very restricted range, and all seem to be 

confined to fairly limited environmental conditions. 

In many of their relations to environment they resemble the Foraminifera.4 Both Foraminifera and ostracodes that are found at extreme depths in tropical 

climates are found in much shallower water in northern 

regions; for both classes of organisms cold water is an 

environmental factor limiting the distribution of the 

species. As an illustration of the distribution of presentday Ostracoda I shall cite two examples. Pseudocythere 

caudata occurs at the present time along the Norwegian 

coast at a depth of about 75 meters, whereas off Buenos 

Aires it was found at 3,480 meters where the bottom 

temperature was 0.0° C. Macrocypris minna occurs 

along the Norwegian coast at depths ranging from 35 

to 550 meters, whereas off the coast of Morocco it is 

found at depths ranging from 640 to 1,350 meters. In 

a series such as this, which includes so few ostracodes, 

it is impossible to make any general statement regarding the correlation of the present distribution of living

* Cushman, J. A., Geology and paleontology of the Georges Bank Canyons, Part IV. 

Cretaceous and late Tertiary Foraminifera: Geol. Soc. America, Bull. vol. 47, pp. 

413-440, 1936.

95
96 GEOLOGY AND BIOLOGY OF NOETH ATLANTIC DEEP-SEA COEES

forms with respect to depth as compared with that 

distribution observed in the several cores.

From the foregoing statements it will be evident, I 

believe, that marine ostracodes may be used as an aid 

in determining environmental conditions of the past. 

As fossils they have long been used as horizon indicators 

and particularly in the correlation of oil-bearing strata. 

The principal difficulty in using ostracodes as horizon 

indicators is that all identification must, of necessity, 

be made from the shell alone, and this is often very 

difficult, even with the diverse forms of marine ostracodes. It would be impossible to identify most freshwater forms from an examination of the shell without 

further aid from internal anatomy.

Plate 18 shows in graphic form the positions at which 

ostracode-bearing samples were taken and the distribution of the species in the cores. The numbers at the 

right of each sample correspond to species which are 

listed on plate 18.

A large proportion of the ostracodes found were in 

cores 8, 12, and 13, which were taken at shallower 

depths than the others. Very few were found in the 

cores taken at depths greater than 3,230 meters. At 

these greater depths the thin calcium carbonate shells 

of the ostracodes are presumably dissolved by the greater quantities of carbon dioxide that the cold deep water 

holds in solution. In a total of some 1,175 species

described, Miiller 5 lists only 4 that were taken below 

a depth of 4,200 meters. Of these, 3 were found at 

about 5,000 meters and 1 was doubtful. Only 12 

species were recorded from depths greater than 3,200 

meters, and only 24 had been found deeper than 2,000 

meters. The greatest depth at which a core was taken 

that contained ostracodes was 4,700 meters, this was 

core 3. The greater abundance of ostracodes found in 

the cores taken at depths of less than 3,250 meters is 

thus easily explained.

I|n core 8, which was taken on top of the Faraday 

Hills, a narrow part of the mid-Atlantic ridge, several 

ostracodes (Cyiheropteron sp. (b), Bythocythere constricta, Pseudocythere caudata, Paracytherois flexuosa, 

and P. producta) were found, which appeared nowhere 

else in the cores. Three of these, B. constricta, P. 

caudata, and P. flexuosa, are forms that are at present 

found in the Arctic seas as well as on the western coast 

of the Atlantic. They are also, however, rather widely 

distributed elsewhere but are decidedly cold-water 

forms. Pseudocythere caudata, the most widely distributed of the group, both in the core samples and in present-dayseas, is an unmistakable species. Pseudocy there 

is closely related to another member of the group, 

Bythocythere constricta. Although these data are insuf5 Miiller, G. W., Fauna und flora des Golfes von Neapel; Ostracoden: Zool. sta. 

Neapel, Mon. 21, pp. 173-387,1894.

TABLE 14.—Geographic distribution and depth and temperature ranges of the ostracodes

Poly cope orbicularis _ __ _

B. obtusata ..

Bairdiasp... .

Eucythere declivis.

Krithe bartonensis

K. glacialis

K. tumida. _

Hemicythere sp. (?)

Cythereis tuberculata _ _

C. echinata _

C. jonesi. .

C. ericea _ __ __

C. sp_____ __________ _ _

Cyiheropteron alatum.

C. hamatum .

C. inflatum. ______ __

C. mucronalatum. _ _

C. sp. (a)____ _._ _ _ _

C. sp. (b). _______ _

Paracytherois flexuosa..... __ _ _ _

P. producta ______ _________ _ ____

Mid-Atlantic

X 

X

X

X

X

X

X 

X

X

I NorthAtlantic

1

X

X

X 

X

X

X

X

X

X

X

X

British Isles

X

X

X 

X

____

X 

X

X

X

X 

X 

X

X

Norway

X

X

X

X

X 

X

X

X

X 

X

X 

X 

X

X 

X 

X

X

X

Arctic Ocean

X

X

X

X 

X

X

X 

X 

X

Baffinay

X

X

X

X

Gulf ofSt.Lawrence

X

X

Cape Breton

X 

X 

X

South Atlantic

X

X

X

X

X

X

South Pacific

X

X

X

X

X

X

North Pacific

X

X

Indian Oce

X

X 

X

X

X

Mediterranean

X

X

X

X

X

X

X

X

1fe

X

X

~x~

X

X

X

X

X

X

X

X

X

Temperature'

a 

1

X

X

X

X

X 

X 

X

?

•0"3

o

X 

X 

X 

X

X 

X

X

X

X 

X 

X

"x"

X 

X 

X

X

X 

X 

X 

X 

X

Depth 3

1

1M

X 

X

"x"

X 

X

X 

X 

X 

X

X

"x"

X 

X

"x"

X

C,

8

Q

X 

X 

X 

X

X 

X 

X 

X

X 

X 

X 

X 

X

?

X 

X 

X

? 

X 

X

"x"

1 Beported in sediments of Pleistocene age or older.

8 Previous record of species. The present marine climate is taken as the mean temperature.

» Previous record of species. The 100-fathom (183-meter), or Murray's line, is taken as the boundary between shallow and deep water.
PAET 4. OSTRACODA 97

ficient to warrant more than a general statement, they 

seem to suggest colder water on the Faraday Hills at 

the periods represented by the various samples in this 

core. Besides the three Arctic species mentioned, all 

the other ostracodes found in core 8 are cold-water 

forms; Polycope orbicularis was found only in this core.

The present geographic distribution of all the species 

found in the cores is given in table 14, page 96, but the 

environmental factors are given in the systematic 

description of the individual species that follows. 

A column in table 14 summarizes the available information on bathymetric distribution. These data are 

inconclusive, however, because the records of depth 

ranges are either too scarce or too uncertain to place 

much confidence in them. The data in the column of 

table 14 giving present water temperatures in which 

these species have been found are also very general. 

In addition, the samples generally do not contain a 

sufficient number and variety of ostracode species to 

obtain the advantages of multiple evidence that a whole 

fauna would offer. These data, however, are of sufficient interest to be presented, whether they agree or 

disagree with other information.

The distribution of each species in the core samples is 

given in table 15. It is greatly to be hoped that more 

extensive core sampling will be possible in the future, 

so that a much more complete picture of conditions may 

be obtained.

SYSTEMATIC DESCRIPTIONS OF THE SPECIES

I follow G. 0. Sars' classification in the treatment of 

the ostracodes here discussed.

Suborder CLADOCOPA Sars 

Family POLYCOPIDAE Sars 

Genus POLYCOPE Sars

The genus Polycope includes several species, all of 

which are remarkable for the more or less orbicular 

shape of the shells as seen from the side. The valves 

are quite thin and are ordinarily smooth, although in 

some species they may be closely punctate or reticulate.

Polycope orbicularis Sars 

Plate 19, figure 13

Four specimens of this peculiar ostracode were obtained from samples H-69 and H-70, about 0.5 meter 

below the top of core 8. Length 0.74 millimeter, 

height 0.61 millimeter. Core 8 was. taken at a depth 

of 1,280 meters (700 fathoms), whereas the present 

distribution of this species seems to be confined to 

much shallower seas; it has never been recorded from 

water more than 290 meters deep. It is a common 

form along the coasts of Norway, where it is found at 

very moderate depths, 11 to 36 meters, on a sandy 

bottom covered with a thin layer of mud. It swims

TABLE 15.—-Distribution of the ostracodes in the core samples

Core..-- _ ___ --------- _ -.. __ __

Position of sample, in centimeters, below top of core

B. obtusata... ..

Bairdiasp. ... ...

Eucythere declicis.. _ -.

Krithe bartonensis -._-___-_____._ _____-_-_._-_..____

K.glacialis. .... ... ..... _. ..

K.tumida. .... ...... .. _____ ____ _ _ _ ._.

Hemicythere ? sp_ -

Cythereis tufoerculata __ _ C. echinata. ............ ._ _ _ __

C.jonesi. ------ ___ -

C.ericea. ....... ................ ..... ...... .... .

C.sp.. ............ ... ... .,

Cytherovteron alatum..

C.hamatum ___ ______ ______ _ _ . _ . -

C.inflatum.— .... .. _ .____-__-_ _ _ -_-._ _ _ . .

C.mucronalatum.---. . .

C. (sp. a). ............. __. - .-..-

C.(sp.b). ................................. ..- _-

Bythocythere constrkta. ........... .... ... ...... ....

Pseudoci/there caudata . ... . . . .

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98 GEOLOGY AND BIOLOGY OF NOETH ATLANTIC DEEP-SEA CORES

rapidly along the bottom but evidently is restricted to 

a benthonic existence. The present distribution of this 

form includes the British Isles, Spitzbergen, Cape of 

Good Hope, and the Torres Straits. At the Cape of 

Good Hope and at Torres Straits it was captured at a 

depth of about 275 meters (150 fathoms) on a sandy 

bottom by the Challenger Expedition.6 The temperature at 275 meters at the Cape of Good Hope was 8.3° C.

Suborder PODOCOPA Sars

Family CYPRIDAE Baird

Genus MACRO CYPRIS Brady

Macrocypris includes several species having very 

solid shells, which are rather elongate and which are 

acutely produced at the posterior end. The inner 

duplicatures of the shells are broad and have a narrow 

marginal zone with transverse striations. Scars of 

muscle attachments are arranged hi a circular pattern.

Macrocypris minna (Baird)

Plate 19, figure 26

Ten specimens of this large creamy white form were 

obtained from cores 12 and 13. Most of the individuals 

were miniature, but three adults were obtained from 

sample H-137, about 0.2 meter below the top of core 

13. Length 2.12 millimeters, height 0.83 millimeter. 

The immature specimens came from samples H-113, 

H-131, and H-133a in core 12, and H-136 in core 13. 

Core 12 was taken at a depth of 3,230 meters (1,770 

fathoms) and core 13 at 1,955 meters (1,070 fathoms). 

This ostracode, by far the largest and finest of the 

marine Cypridae, is strictly a bottom-dwelling form. 

On the bottom it crawls slowly. It is at present a 

common form along the Norwegian coast but is found 

at much shallower depths than those at which the cores 

were taken. Along the Norwegian coast and also off 

the Shetland Islands it is found at depths ranging from 

35 to 550 meters. Off the coast of Morocco, however, 

it has been obtained at depths ranging from 640 to 1,350 

meters. Macrocypris minna is known as a fossil from 

post-Tertiary beds in Calabria.

Genus BYTHOCYPRIS Brady

The shell in this genus is more or less oval, without 

hairs, and somewhat compressed, and the sides are 

entirely unarmed. Bythocypris is closely allied to the 

genus Bairdia, although the two genera may easily be 

distinguished by the difference in the shape of the shell. 

The genus is composed entirely of bottom-dwelling 

forms.

• Brady, G. S., Report on the Ostracoda dredged by the H. M. S. Challenger during 

the years 1873-1876, Challenger Kept., Zoology, vol. 1, pp. 16, 21, 169-170, 1880.

Bythocypris bosquetiana (Brady)

Plate 19, figure 22

Six specimens, five of which were mature individuals, 

were found in samples H-126, H-130, H-133a, H-133b, 

and H-134 in core 12. One adult was found in sample 

H-147, 1.1 meters below the top of core 13. Length 

1.19 millimeters, height 0.74 millimeter. This species 

is found along the Norwegian coast at the present time 

at a depth of 275 meters. It has also been taken in 

the Atlantic at a depth of 860 meters, hi the Mediterranean at 1,280 meters, in Bass Straits (between 

Australia and Tasmania), and in the waters of the 

West Indies. G. O. Sars 7 includes B. reniformis as a 

synonym, which would increase somewhat the range of 

distribution, but I am inclined to follow Miiller's 

synonomy 8 and consider B. reniformis as a distinct 

species. The shape of the shell of B. reniformis is 

quite different from that of the shells found in the core 

samples. B. bosquetiana is a bottom-living ostracode.

Bythocypris obtusata (Sars) 

Plate 19, figure 17

Three adult and five immature specimens of this 

species were found in samples H-20, and H-30 in core 

4; H-54a in core 7; H-126, H-131, H-133a, and 

H-133b in core 12; and H-141 in core 13. An adult 

form in core 4, sample H-30, was found 2.5 meters 

below the top of the core; one immature specimen was 

found in the top layer of core 7, sample H-54a; and the 

individuals in each of cores 12 and 13 were found 

between 1.3 and 1.9 meters below the top. Core 4 

was taken at a depth of 3,955 meters (2,165 fathoms) 

and core 7 at 3,250 meters (1,780 fathoms). Length 

of specimen 1.26 millimeters, height 0.80 millimeter. 

At present this species is found at a depth of 145 to 

165 meters along the Norwegian coast. It is also 

found in the waters adjacent to the British Isles and 

near the Kerguelen Islands, where it was found at a 

depth of 1,490 meters. Fossil forms have been reported from post-Tertiary deposits in Calabria.

Genus BAIRDIA M'Coy

Bairdia includes ostracodes with rhomboidal shells 

of comparatively great height and somewhat attenuated 

extremities that are usually denticulate at the edges of 

the valves. In the living state they are covered with 

coarse recurved hairs. This genus was described by 

M'Coy in 1844 and has been confused by many authors

7 Sars, G. O., An account of the Crustacea of Norway, vol. 9, Ostracoda, pp. 64-65, 

Bergen, Bergen Museum, 1928.

s Miiller, G. W., Das Tierreich. Lief. 31, Ostracoda: K. preuss. Akad. Wiss., 

p. 250, 1912.
GEOLOGICAL SURVEY 

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PROFESSIONAL PAPER 196 PLATE 18

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CHART SHOWING POSITION OF THE OSTRACODE-BEARING SAMPLES IN THE CORES AND THE DISTRIBUTION OF SPECIES.

262255—41 (Face p.
PART 4. OSTRACODA 99

with Nesidea. I shall use the genus in the restricted 

sense employed by G. O. Sars. Bairdia includes 

ostracodes that are strictly bottom-dwelling forms and 

that are widely dispersed at the present time. The 

genus is most abundantly distributed in tropical and 

southern waters, where in many places it is the dominant 

genus.

Bairdia sp. 

Plate 19, figure 27

Seven individuals of an ostracode referable to this 

genus were found in cores 8, 12, and 13. Four immature specimens were found within 0.4 meter of the top of 

core 8 in samples H-61a, H-64, and H-69, one immature specimen was found in core 13, sample H-133b, 

0.3 meter below the top of the core; and an adult was 

found 2.1 meters below the top of core 12, sample H-137. 

The anterior end of the shell of the adult specimen was 

broken off, but it was clearly identical with the immature forms. Length of adult 1.50 millimeters, height 

0.96 millimeter. The figured specimen is an immature 

form from core 8, sample H-61a, just beneath the top 

layer of the core. Length of figured specimen 1.26 millimeters, height 0.82 millimeter. I have been unable to 

identify this species with any described in the available 

literature. It is undoubtedly of Recent age.

Family CYTHERIDAE Baird 

Genus EUCYTHERE Brady

This genus contains species that are characterized by 

a triangular shell, which is compressed hi front and 

much higher at the anterior end than at the posterior. 

The valves are thin and pellucid and possess wide marginal zones, which are crossed by pore channels. The 

edges are smooth with few scattered hairs. This 

genus has only two species.

Eucythere declivis (Norman)

Plate 19, figures 2-3

Two adult specimens of this unmistakable species 

were found in core 8, sample H-68, and core 13, sample 

H-144, 0.3 and 0.8 meter, respectively, below the tops 

of the cores. Length 0.67 millimeter, height 0.41 millimeter. This species is at present distributed along the 

Norwegian coast, the British Isles, the Gulf of St. 

Lawrence, Franz Joseph Land, the Mediterranean, and 

along the European coast. In the Indian Ocean it was 

found at a depth of 358 meters. Cores 8 and 13 were 

taken at 1,280 and 1,955 meters (700 and 1,070 fathoms). Eucythere declivis, like the other Cytheridae, is a 

form that crawls slowly along the bottom.

Genus ERITHE Brady and Norman

The genus Krithe includes ostracodes with a thin and 

pellucid shell, which has a smooth, polished surface 

with marginal zones that contain scattered pore canals

Core 

number

3

7

8-__._

12....

Sample 

number

H-158_.

H-42___

H-49a_ _

H-64_ _ _

H-69._.

H-133b _

Distance 

below 

top of 

core, in 

meters

0 0

1 8

2

2

4 

6

2 1

Number 

of specimens

1

1

1

2

2 

4

1

Core 

number

13

13

13

13

13"""

13....

Sample 

number

H-137 __.

H~138.__

H-144_ _ .

H-147___ 

H-150__-

H-153__.

Distance 

below 

top of 

core, in 

meters

0 3

4

6

8

1 1 

1 4

1 7

Number 

of specimens

ft

1

1

1

1 

1

1

rather irregularly arranged. At the anterior extremity 

is a thin hyaline border. Three species were found in 

the cores.

Krithe bartonensis (Jones)

Plate 19, figure 5

Numerous specimens of this species were found hi 

most of the cores. The locations are given in table 16.

TABLE 16.—Distribution oj Krithe bartonensis (Jones) in the cores

Length 0.75 millimeter, height 0.37 millimeter. Core 

number 3 was obtained at a depth of 4,700 meters 

(2,575 fathoms) and core 6 at 4,125 meters (2,260 

fathoms). At the present time this species is common 

along the Norwegian coast, where it is found at depths 

ranging between 35 and 90 meters on a muddy bottom. 

It is strictly a bottom-dwelling form. Its present distribution also includes the British Isles, Iceland, the 

Bay of Biscay, the European coast, and Kerguelen 

Island. At Kerguelen Island it was found at a depth of 

3,210 meters. It is known as a fossil from Tertiary 

and post-Tertiary deposits in Scotland, England, and 

Norway.

Krithe glacialis Brady, Crosskey, and Robertson

Plate 19, figure 9

Twenty individuals of this species, which is very 

closely allied to K. bartonensis, were taken from cores 

7, 12, and 13. In core 7, samples H~49a and H-54a, 

it was found at 0.3 and 1.3 meters below the top of 

the core;in core 12, samples H-121, H-130, and H-133a, 

at 0.8,1.7, and2.1 meters;andin core 13,samples H-139, 

H-145, H-147, and H-152 at 0.4, 1.0, 1.1, and 1.7 

meters. Length of figured specimen 0.83 millimeter, 

height 0.48 millimeter, K. glacialis was known as a 

fossil in post-Tertiary beds hi Scotland and Norway for 

some time before it was taken in dredge samples in 

the North Atlantic. It is not known from any other 

localities and apparently is another of the northern 

ostracodes.

Krithe tumida Brady

Plate 19, figure 1

A large number of specimens of this species were 

found in cores 6,7,12, and 13, the distribution of which 

is given in table 17.
100 GEOLOGY AND BIOLOGY OF NORTH ATLANTIC DEEP-SEA CORES

TABLE 17. — Distribution of Krithe tumida Brady in the cores

Core

number

6— __

6— __

6__.__

7 ._

7_._._

12_.__

12____

12____

Sample

number

H-40___

H-42...

H-46___

H-49a. _

H-54a. _

H-114__

H-121__

H-129--

Distance

below

top of 

core, in

meters

1.5

1.8

2.6

. 2

1.3

.2

\8

1.6

NumDGF 

of

speci1

1

1

2

1

1

1

1

Core

number

12__-

12....

12___.

12_.__

13_-__

13.-__

13.__.

13___.

Sample

number

H-130...

H-131-..

H-133a_.

H-133b__

H-137.__

H-141__.

H-144_ . _

H-150...

Distance

below

top of 

core, in

meters

1.8

1.9

2. 1

2.4

. 3

.6

. 8

1.4

Numof

speci1

1

4

2

1

1

3

1

This ostracode is a southern form in its present 

known distribution, having been found living at great 

depths in the South Atlantic and at 3,470 meters at 

Funafuti but so far it has not been reported from the 

Northern Hemisphere. It is significant, however, that 

in southern waters it is found only at great depths, 

where cold water prevails the year around. For 

example, off Buenos Aires, members of the Challenger 

Expedition found it living on the bottom in gray mud 

at a temperature of 0.0° C. Length of figured specimen 0.61 millimeter, height 0.37 millimeter.

Genus HEMICYTHERE Sars

Hemicytfiere includes forms that have a heavy 

calcareous shell somewhat resembling that of Cythere 

in shape. The valves are rather unequal and have 

much-pitted outer surfaces. This genus is in an intermediate position between Cythere and Cythereis, Eight 

species have been reported from Norway.

Hemicythere sp. (?)

The posterior third of a shell fragment which seems 

to agree most closely with a species of Hemicythere, 

was found in core 9, sample H-83, at 0.8 meter below 

the top of the core. Several species of this genus live 

in the North Atlantic and Arctic Oceans, whereas fossil 

forms are known from Scotland, Norway, and Germany. 

Some of the species are littoral and others live in deep 

water. It is possible that this species belongs to the 

deep-water northern group.

Genus CYTHEREIS Sars

This very large genus contains ostracodes whose 

shells have uneven surfaces, variously formed spines or 

projections, and denticulated anterior and posterior 

extremities. The sculpturing of the valves is usually 

less coarse than in Hemicytfiere and in some species 

it may be quite inconspicuous.

Cythereis tuberculata (Sars) 

Plate 19, figure 20

Six specimens of this species were found in cores 

6, 7, and 8. In core 6 the ostracodes were located in

sample H-38 and in core 7 in sample H-54a, both 1.2 

meters below the top of the core, and in core 8, samples 

H-69 and H-71, at about 0.5 meter below the top. 

Length 0.92 millimeter, height 0.52 millimeter. This is 

one of the commonest and most widely distributed of 

ostracodes living in British waters. It is also common 

along the Norwegian coast. In both regions it is now 

found at depths of 18 to 55 meters. It is further 

distributed in the waters near Iceland, and Spitzbergen, in the Bay of Biscay, the Mediterranean, and 

Baffin Bay, near the West Indies, and in the South 

Pacific, where it was found at 358 meters. It is also 

found in the deep cold waters of Vineyard Sound off 

the Massachusetts coast.9 Fossils of this species have 

been found in the post-Tertiary beds of Scotland, England, Ireland, and Norway.

Cythereis echinata Sars 

Plate 19, figure 24

Numerous specimens of this distinctive species were 

found in cores 3, 4, 6, 7, 12, and 13. Their distribution 

is given in table 18.

TABLE 18.—Distribution of Cytherois echinata Sars in the cores

Core 

number

3--.-

4,____

6— _-

7— .-

12__._

Sample 

number

H-158-.

H-21___

H-47_._

H-48___

H-133a_

Distance 

below 

top of 

core, in 

meters

0.0 1.1

2.8

.0

2. 1

Number 

of specimens

1

1

1

1

3

Core 

number

12.__.

13--_-

13.__-

13-.--

13_--_

S ample 

number

H-133b__

H-135.__

H-138--.

H-139-.-

H-144-5-

Distance 

below 

top of 

core, in 

meters

2 2

0

4

8

9

Number 

of specimens

1

?,

?,

1

2

Length 1.19 millimeters, height 0.75 millimeter. 

At the present time this is a common form along the 

Norwegian coast, where it is found on a muddy bottom 

at depths of 55 to 90 meters. It is also found near the 

Lofoten Islands at 550 meters, and the Challenger 

Expedition found it in the abyssal parts of the North 

Atlantic and South Atlantic at depths ranging from 

1,825 to 2,600 meters. North of Tristan d'Acunha it 

was taken at 2,600 meters in globigerina ooze, where 

the bottom temperature was 2.3° C.

Cythereis dunelmensis Norman

Plate 19, figure 21

Only one specimen of this highly ornamented ostracode was found, and that was in sample H-133a, 2.1 

meters below the top of core 12. Length 0.99 millimeter, height 0.48 millimeter. C. dunelmensis is 

decidedly a northern form at the present time. It is 

common along the coast of Norway, where it is found

9 Cushman, J. A., Marine Ostracoda of Vineyard Sound and adjacent waters: 

Boston Soc. Nat. Hist., Proc. vol. 32, no. 10. p. 376,1906.
PART 4. OSTEACODA 101

at depths of 18 to 90 meters on a muddy bottom, in the 

waters around the British Isles, Iceland and Spitzbergen and in Baffin Bay and the Gulf of St. Lawrence. 

As a fossil it is known from the post-Tertiary beds of 

Scotland, England, and Ireland.

Cythereis jonesi Baird

Plate 19, figure 14

A single specimen of this species was found in core 12, 

sample H-130, at 1.8 meters below the top of the core. 

Length 0.92 millimeter, height 0.54 millimeter. This 

is a more widely distributed species than C. dunelmensis, 

although it too appears to be a northern cold-water 

•form. In upper Oslo Fjord it lives on a muddy bottom 

at depths ranging from 55 to 90 meters. It has also 

been found in the waters adjacent to the British Isles 

and Spitzbergen and in the Bay of Biscay and the 

Mediterranean. Fossil forms have been found in the 

post-Tertiary beds of Ireland, hi Pliocene deposits in 

England, and in Eocene beds hi Belgium and France. 

This species and Krithe bartonensis are the only ostracodes found in the present series of cores that have also 

been found as fossils which antedate the Pleistocene.

Cythereis ericea (G. Brady)

Plate 19, figure 23

Two specimens of this very spiny ostracode were 

found in cores 7 and 12. In core 7, sample H-48, the 

figured specimen was at the very upper level of the 

core, whereas in core 12, sample H-130, an immature 

form, evidently of the same species, was found at 1.8 

meters below the top. Length 1.29 millimeters, 

height 0.71 millimeter. This species appears to be a 

southern form at the present time and has to date not 

often been encountered in dredged samples. It was 

discovered by the members of the Challenger Expedition 

off the coast of Brazil, near Pernambuco, at a depth of 

1,235 meters on a mud bottom. Since then it has been 

reported, but with some uncertainty, from two other 

localities, one off the southern tip of Africa and the 

other in the Indian Ocean off the northwestern coast 

of Australia. Both these collections were made in 

deep water, 2,630 and 3,125 meters, respectively, so 

that C. ericea is evidently a cold-water species.

Cythereis sp.

Plate 19, figures 18-19

One specimen of this distinctive species was found 

in core 13, sample H-135, at the very top of the core. 

I have not been able to identify it definitely with any 

described species of Cythereis in the available literature. 

Length 0.88 millimeter, height 0.49 millimeter.

Genus CYTHEROPTERON Sars

This genus is composed of ostracodes possessing more 

or less prominent lateroventral alaeform projections on 

each valve. The shape of the shell shows much variation, although it is generally thin, pellucid, and unsculptured. Cytheropteron is definitely a northern 

genus, its range extending into the Arctic seas on both 

sides of the Atlantic. Six species were found in the 

core samples.

Cytheropteron alatum Sars

Plate 19, figure 12

Eight individuals of this species were found in core 

3, sample H-158; core 7, sample H-49a; core 8, sample 

H-69; core 10, sample H-102; and core 12, sample 

H-113. In all the cores except 10 the ostracodes were 

found within 0.4 meter of the top of the core. In 

core 10, taken at 4,190 meters, a single specimen of 

this species was found 1.3 meters below the top. 

This was the only ostracode found in core 10. Length 

0.78 millimeter, height 0.41 millimeter. C. alatum is 

another form found principally in northern waters, 

but it is also found in southern waters. Its present 

distribution includes the southern coast of Norway and 

upper Oslo Fjord, where it occurs at 55 meters, the 

waters of the British Isles, and the Shetland Islands. 

It has been reported at Funafuti, but at what depth I 

am unable to determine with certainty (3,470 meters?).

Cytheropteron hamatum Sars 

Plate 19, figure 7

One specimen was found 0.2 meter below the top of 

core 8 in sample H-64. Length 0.69 millimeter, 

height 0.41 millimeter. Another northern form, this 

species is at present distributed along the Norwegian 

coast and the Lofoten Islands at depths of 220 to 550 

meters on muddy bottoms. It has also been taken 

near Spitzbergen and in Davis Strait. It is known as a 

fossil in post-Tertiary beds in Scotland.

Cytheropteron inflatum Crosskey

Plate 19, figure 6

Two specimens were found, in core 12, sample H-128, 

and core 13, sample H-138, -at 1.5 and 0.4 meters, 

respectively, below the tops of the cores. Length 0.70 

millimeter, height 0.48 millimeter. Also a northern 

form, it is at present found along the coast of Norway 

at depths of 55 meters on muddy sand, near the British 

Isles, and in the Arctic Ocean (Baffin Bay). It occurs 

as a fossil in Scotland in post-Tertiary deposits and 

also in post-Tertiary deposits in Canada.
102 GEOLOGY AND BIOLOGY OF NOETH ATLANTIC DEEP-SEA COEES

Cytheropteron mucronalatum Brady

Plate 19, figure 25

Two specimens of this striking form were found in 

core 12, samples H-114 and H-133a, at 0.2 and 2.1 

meters below the top of the core. Length 1.39 millimeters, height 0.85 millimeter. C. mucronalatum is 

decidedly a cold, deep-water species. It is widely distributed hi the Pacific Ocean from Patagonia to Japan 

and in the Atlantic has been taken between the Azores 

Islands and the Bay of Biscay (slightly south of core 12 

at a depth of 3,060 meters in globerigina ooze. This 

had previously been its most northern record in the 

Atlantic. The Challenger Expedition recorded this 

species hi globigerina ooze at a depth of 3,420 meters 

off the Caroline Islands, near the equator, where the 

bottom temperature was 1.3° C. In the North Pacific 

it was found at latitude 36° N. in gray ooze at a depth 

of 3,740 meters, where the bottom temperature was 

1.3° C. Again, off the coast of Chile near the Juan 

Fernandez Islands, it was found on red clay at a depth 

of 3,330 meters, where the bottom temperature was 

1.2° C.

Cytheropteron sp. (a)

Plate 19, figure 10

Two evidently immature specimens were found 0.3 

meter below the top of core 6, sample H-35, and at the 

top of core 8, sample H~61a. The shape of the shell 

and the rounded processes lead me to believe that these 

are immature forms, but of what species I have been 

unable to determine. Length 0.68 millimeter, height 

0.48 millimeter.

Cytheropteron sp, (b)

A broken right valve, which broke up further when 

handled, was found 0.6 meter below the top of core 8, 

sample H-71. The shell fragment of this truly remarkable ostracode showed two lateral processes, one 

behind the other, which were extremely serrated on 

their posterior edges.

Genus BYTHOCYTHERE Sars

This genus includes forms which have rather tumid 

shells, although the shape varies somewhat. They 

have lateral expansions of more or less prominence and 

the posterior end of the shell is obtusely pointed. The 

valves are comparatively thin and have a smooth or 

slightly punctate surface.

Bythocythere constricta Sars 

Plate 19, figure 16

Two specimens of this species were obtained from 

samples H-64 and H-71 in core 8 at 0.2 and 0.6 meter, 

respectively, below the top. Length 0.68 millimeter, 

height 0.38 millimeter. This is also a northern ostracode; at present it is distributed along the Norwegian 

coast at depths of 55 to 73 meters on soft clay bottoms. 

It is also found in the waters of the British Isles, Spitzbergen, Fosse de Cap Breton, and in the Bay of Biscay. 

Fossil forms are known from the post-Tertiary deposits 

of Scotland and Netherlands.

Genus PSEUDOCYTHERE Sars

Pseudocythere is a very easily identified genus and 

may be recognized by the peculiar shape of the shells. 

The shells are compressed, lack lateral expansions, and 

their posterior extremities are produced into a taillike 

process. The surfaces of the valves are smooth, but 

they have wide marginal zones crossed by prominent 

pore channels. The genus is closely allied to Bythocythere. Four species are now known, three from southern waters and one from northern.

Pseudocythere caudata Sars 

Plate 19, figure 15

Numerous specimens of this easily recognized species 

were found near the upper part of core 8 in samples 

H-61a,- H-62, H-64, H-68, H-69, and H-71. These 

samples were found within 0.6 meter of the top of the 

core. Length 0.78 millimeter, height 0.37 millimeter. 

This is a widely distributed species. It is found hi 

the Olso Fjord and other Norwegian fjords at a depth 

of 73 meters. It is also distributed around the British 

Isles, the Bay of Biscay, the Mediterranean, Fosse de 

Cap Breton, the NoFth Atlantic as far as Franz 

Joseph Land, and the South Atlantic to the Kerguelen 

Islands. Near the Kerguelen Islands it was taken at 

depths ranging from 36 to 220 meters, whereas off the 

coast of Brazil (Buenos Aires) it was taken at 3,470 

meters on a gray mud bottom, where the temperature 

was 0.0° C. It is found as a fossil in the post-Tertiary 

beds of Scotland and Ireland.

Genus PARACYTHEROIS Muller

This genus contains ostracodes with an elongate 

shell that is quite fragile. The marginal zones are 

comparatively broad and are crossed by irregular pore 

channels. Pamcytherois was first found in the Mediterranean but has since then been taken in northern waters. 

Two species were found in the core samples.

Paracytherois flexuosa (Brady)

Plate 19, figure 11

Two specimens were found in core 8, samples H-61a 

and H-69, within 0.4 meter of the top of the core. 

Length 0.70 millimeter, height, 0.24 milhmeter. At 

present this species is found off the western coast of 

Norway in deep water among hydroids. It has also 

been found hi the waters off the British Isles, Nether-
PAKT 4. OSTEACODA 103

lands, the Fosse de Cap Breton, Bay of Biscay, the 

Mediterranean, and as far north as Franz Joseph Land.

Paracytherois producta (Brady and Norman)

Plate 19, figure 8

Three specimens were found in core 8, samples H-64, 

H-69, and H-71, at 0.2 and 0.6 meter below the top. 

Length 0.70 millimeter, height 0.30 millimeter. 

Although the length of the ostracode found in the core 

sample is considerably greater than that given by Sars, 

the shape of the shell is very similar. P. producta is at 

present known only from Bergen Fjord and other places 

along the western coast of Norway and in the Mediterranean.

Genus PARADOXSTOMA Brady

This genus includes ostracodes with thin, fragile 

shells usually somewhat higher behind than in front. 

The valves have narrow inner duplicatures and narrow 

marginal zones with inconspicuous pore channels. The 

genus is distributed in both northern and southern 

waters.

Paradoxstoma ensiforme Brady

Plate 19, figure 4

Two specimens were found in core 8, sample H-71, 

0.6 meter below the top and one in core 13, sample 

H-137, 0.3 meter below the top. Length 0.78 

millimeter, height 0.43 millimeter. At present this 

form is found along the Norwegian coast, in the waters 

off the British Isles, and in the Bay of Biscay. The 

Challenger Expedition apparently found it in mud 

clinging to the anchor in Vigo Bay, Spain, at a depth of 

20 meters. This is a rather doubtful record, however. 

In the Indian Ocean it has been found at a depth of 

358 meters. It is known as a fossil in the post-Tertiary 

beds of the British Isles.

DISCUSSION

Brady, Crosskey, and Robertson 10 in 1874 found that 

in the postglacial beds in Scotland the fauria was the 

same as that inhabiting the adjacent seas, whereas in 

the glacial deposits the invertebrate fauna was mainly 

northern. The Mollusca of the glacial beds included 

some Arctic forms, which are absent from the neighboring seas. Moreover, some species that are now common in the Arctic were common in the glacial beds but 

are very rare in the seas adjacent to the British Isles. 

Of the ostracodes, 18 were either extinct or as yet 

unknown as living forms, and 10 were Arctic but still 

found in British waters. The fossil ostracodes from the 

glacial deposits of Scotland were found to be almost

10 Brady, a. S., Crosskey, H. W., and Robertson, D., A monograph of the postTertiary Entomostraca of Scotland: Paleontographical Soc. London, vol. 28, pp. 

96-99, 1874.

identical with those of Norway, and almost all were still 

living hi neighboring seas. A great similarity between 

the fauna of the Scotch glacial beds and the fauna of the 

glacial beds of Canada was also observed.

It is of interest to note that northern forms predominate among the ostracodes from these North Atlantic 

cores. Only two of the species identified have not 

previously been known from northern waters, and 10 

species are definitely Arctic forms. Furthermore, most 

of the species are decidedly cold-water forms and 

when found in tropical waters are confined to great 

depths where nearly freezing temperatures exist the 

year around. A few species that have a wider temperature range live not only in cold waters but also in 

the deep, warm water of the Mediterranean. The 

water below about 230 meters in the Mediterranean 

maintains a yearly temperature between 13° and 14° C. 

Eight species are forms that are at present distributed 

on the western shores of the Atlantic, in Baffin Bay, 

Davis Straits, off Cape Breton, or in the Gulf of St. 

Lawrence.

The age of the ostracodes found in the core samples is 

difficult to estimate with any certainty. Those in the 

upper levels of the core samples certainly represent 

Recent forms (see plate 18). All the identified species 

are known as living forms today, whereas 12 of the 27 

species are also known as fossils in the British Isles, 

Norway, Europe, and Canada. The sediments from 

which the core samples were obtained have been estimated from other evidence to be of Pleistocene and 

Recent age, and, as all except two of the species of 

ostracodes known as fossils have also been found in the 

Pleistocene beds in the above-mentioned countries, this 

seems quite reasonable. One ostracode, Cythereis 

jonesi, has been found as a fossil in Eocene deposits in 

France and in Pliocene deposits in England. However, 

it is at present represented by living forms in northern 

waters, the Bay of Biscay, and the Mediterranean. 11 

One specimen of Cythereis jonesi was obtained from 

sample H-130, core 12, taken at 3,230 meters. Krithe 

bartonensis has also been found in Tertiary and postTertiary beds in Scotland, England, and Norway. Its 

present distribution includes northern waters, the midAtlantic, and great depths in the Indian Ocean off 

Kerguelen Island. Many specimens of this ostracode 

were found in the cores.

The predominance of distinctly cold-water ostracodes 

and the prevalence of Arctic forms suggest that the 

water temperatures in this part of the North Atlantic 

were formerly much lower. However, the distribution 

of the ostracodes in these cores shows no evident relationship to the cold and warm zones indicated by the 

lithology of the sediments (see part 1, Lithology and

" Brady, G. S., Crosskey, H. W., and Robertson, D., idem., pp. 171-172.
104 GEOLOGY AND BIOLOGY OF NOETH ATLANTIC DEEP-SEA COEES

geologic interpretations) and by the pelagic Foraminifera. (See part 2, Foraminifera.) But the ostracodes 

hi these cores are all bottom dwellers that lived 1,280 

meters or more below the surface, and consequently 

there seems little reason to expect that they would be 

as sensitive to changes in surface-water temperatures as 

would strictly pelagic organisms. At depths of 1,280 

meters or more the water temperatures probably were

somewhat lower during the glacial stages of the Pleistocene than they are today, but it seems likely that any 

changes in temperature at those depths would have 

been so slow that they lagged far behind the climatic 

changes that produced them. Possibly the change was 

so slow that it masked the alternation of cold and warm 

epochs that left so clear an impress on the composition 

of the pelagic foraminiferal fauna.
PLATE 19

105
PLATE 19

[All figures magnified 30 diameters]

FIGURE 1. Krithe tumida Brady. Lateral view of right valve. North Atlantic deep-sea core 7, H^-49a.

2-3. Eucythere declivis (Norman). Lateral views of right valve. North Atlantic deep-sea core 8, H-68.

4. Paradoxstoma ensiforme Brady. Lateral view of right valve. North Atlantic deep-sea core 8, H-71.

5. Krithe bartonensis (Jones). Lateral view of right valve. North Atlantic deep-sea core 7, H-49a.

6. Cytheropteron inflatum Crosskey. Lateral view of right valve. North Atlantic deep-sea core 13, H-138.

7. Cytheropteron hamatum Sars. Lateral view of right valve. North Atlantic deep-sea core 8, H-64.

8. Paracytherois producta (Brady and Norman). Lateral view of right valve. North Atlantic deep-sea core 8, H-71.

9. Krithe glacialis Brady, Crosskey, and Robertson. Lateral view of left valve. North Atlantic deep-sea core 13, H-147.

10. Cytheropteron sp. (a). Lateral view of left valve. North Atlantic deep-sea core 6, H-35.

11. Paracytherois flej.uosa (Brady). Lateral view of right valve. North Atlantic deep-sea core 8, H-69.

12. Cytheropteron alatum Sars. Lateral view of left valve. North Atlantic deep-sea core 8, H-69.

13. Polycope orbicularis Sars. Lateral view of right valve. North Atlantic deep-sea core 8, H-69.

14. Cythereis jonesi Baird. Lateral view of right valve. North Atlantic deep-sea core 12, H-130.

15. Pseudocyihere caudata (Sars). Lateral view of right valve. North Atlantic deep-sea core 8, H-61a.

16. Bythocythere constricta Sars. Lateral view of left valve. North Atlantic deep-sea core 8, H-71.

17. Bythocypris obtusata Sars. Lateral view of right valve. North Atlantic deep-sea core 4, H-30.

18-19. Cythereis sp. Lateral views of right valve. North Atlantic deep-sea core 13, H-135.

2Q. Cythereis tuberculata Sars. Lateral view of left valve. North Atlantic deep-sea core 8, H-71.

21. Cythereis dunelmensis Norman. Lateral view of right valve. North Atlantic deep-sea core 12, H-133a.

22. Bythocypris bosquetiana (Brady). Lateral view of left valve. North Atlantic deep-sea core 12, H-130.

23. Cythereis ericea (Brady). Lateral view of left valve. North Atlantic deep-sea core 7, H-48.

24. Cythereis echinata Sars. Lateral view of left valve. North Atlantic deep-sea core 7, H-48.

25. Cytheropteron mucronalatum Brady. Lateral view of right valve. North Atlantic deep-sea core 12, H-133a.

26. Macrocypris minna (Baird). Lateral view of right valve. North Atlantic deep-sea core 13, H-137.

27. Bairdia sp. Lateral view of right valve. North Atlantic deep-sea core 8, H-61a. 

106
GEOLOGICAL SURVEY PROFESSIONAL PAPER 196 PLATE 19

OSTRACODA FROM THE NORTH ATLANTIC DEEP-SEA CORES.

INDEX

A Page 

Acknowledgments for aid__ ________ __—____—_—_ XI, XIV, 95

Age of sediments __. — — — - — _ — — — — — _ — — — — - — _— — — - ——--- VIII

alatum, Cytheropteron..________ _ ________________________ ____ — — ___ 97,101, pi. 19

Analyses, chemical_ — — — __— — _— — — _—_——__- — ___— — — _ X 

mechanical ______ — ——_ — _ — __ — — — —-——_—_ — — — — — — — VIII

Archeology, significance of core study for_ __ — _— — —— — _— — _ _ _- XIII-XIV

Arthropoda._— — — — __ — — — — — — — — _ — _ — ___ — —_——— ——_ — — 95

Ash, volcanic, composition and distribution.______—-_ _ — __ — — — — — — — VII

B 

Bairdia _____________________ ________________ ___._.______— — 95,98-99

Bairdiasp——— - — — -__ — — -_-- --_____-------_--------_---.---- 97,99, pi. 19

Barium, in sediments—_—_ — — _____ —______ — __ —— __ — __ — ___ —__ — — — — __- VIII

bartonensis, Krithe_ ___________-_______--_-____-_- ______ 97,99,101,103, pi. 19

Basaltic glass, occurrence and character of--..-__-_ — — — — — — ._________ VIII

Boron, in sediments..______________..__ —_______ __ — _ ———__ VIII

bosquetiana, Bythocypris _ — __ — —____________ ___._--- — — 97,98, pi. 19

Bottom currents,.evidence of __——_- — — —_-_ — -__ — —-__ — - — — _- VII 

Bradley, W. H., introduction by_--_______.._______________________ XIII-XV

Bythocypris—— — - — ____—— „ — — -_ — — — _- — — -—.——__• 95,98

bosqLuetiana. — —— — — — — — — —— — — — — —— — — — — — — 97,98, pi. 19

obtusata. _____________________ ______ _________________________ 97,98, pi. 19

reniformis — — _ — — .— — — — — _ — — — — — — — _ — — - ——__ — — — 98

Bythocythere—— — —— — _- — — _— — — — —— — _ —_ — — — _ — -_ 102

constricta.-_______ —______ _____ — __ — — __— _____ — ___ — -__ 96,97,102, pi. 19

C 

Carbonate, in sediments—_ — _—— — — _ — — ___ — __ — — _— — — — _— — _ — __ VIII

Carnegie Institution of Washington, work on deep-sea cores by _______ VII, XI, XIV

caudata, Pseudocythere. —_ ____— — — — — — — —— _ — __ — 95,96,97,102, pi. 19

Cladocopa- —__ — _-_ —____ — -_ —___—_ — _ — ______ ——____—__ 95,97-98

Climate, relation of sediments to________-_-_________ _______ VII, VIII, X, XIII

Conchoecidae_._ — — — — — — _— — — — — — — _ — — — — — _ — .__ — 95

constricta, Bythocythere-________________________________________ 96,97,102, pi. 19

Core samples, methods used in obtaining._______________________________ XIV-XV

Core stations, location of____ ______________________________________ XIV

Correlation of zones represented in the cores., _______________________ VIII

Crinoids, in sediments________________________________________________________ IX

Currents, bottom, evidence of _______________________________________________ VII

Cypridae____________________________________ _____________________________ 95,98-99

Cythere--___.___.________ _______ ___________________________________________ 100

Cythereis...———— — _-____ —.-_-__ —— — __-—_ — —— _ — — — 100-101

dunelmensis..— — —— — — — _ — _— — — ___- — ______ 97,100-101, pi. 19

eehinata___________________________________________________________ 97,100, pi.19

ericea ______ ______________________________________________________ 97,101, pi.19

jonesi._---_________.______ ___________________________________ 97,101,103, pi. 19

tuberculata_ _______________________________________________________ 97,100, pi. 19

sp_———— — --___-_________-_._._ i _________ 97,101, pi. 19

Cytheridae_______ ____ __________________________________________________ 95,99-103

Cytheropteron_____ _________________________________________________________ 101-102

alatum ______________________________________ 97,101, pi. 19

hamatum.________________________________________ _______________ 97,101, pi. 19

inflatum-.,. — ---- — — — - — — -_ — — — — ____ — __ — _- 97,101, pi. 19

mucronalatum ____________________________________________________ 97,102, pi. 19

sp _ ____ -_-__.___ ___________ ____________________ 96,97,102, pi. 19

D 

declivis, Eucythere_____________________________________________________ 97,99,pi. 19

Diatomaceae_____ ______ ______________ _________________ VIII-IX

Diatoms, distribution of, in sediments ____________________________________ VIII-IX

dunelmensis, Cythereis._______ _______________________ __________ 97,100-101,pi. 19

E 

echinata, Cythereis_____ ____________________ ________________________ 97,100,pi. 19

Echinodermata _____------_-______.___________________ IX

Echinoids, association of._____________________________________________________ IX

Elphidiella__-_ ___________ ___________________ VIII

Elphidium... _____ _____________ _________________________ VIII

ensiforme, Paradoxstoma. ________ ____________________________________ 97,103,pi. 19

ericea, Cythereis_____-_____________ _______ _________________________ 97,101,pi. 19

Eucythere. ________________ ________ ________________________________________ 99

declivis.___________________________________________________________ 97,99,pi. 19

F Page 

Farraday Hills, features of___________________________________ XIV

Faunas, distribution of------------------------------------------------------- IX

Fecal pellets, evidence of, in sediments__--_----_-_---------------____-------- VIII

flexuosa.Paracytherois—-_ — -----__--___----_----_----_-_--- 96,97,102-103,pi. 19

Foraminifera, age and correlation of-.----..-----.----------------------------- VIII

distribution and environmental significance of___----_-----------__ VII-VIII

Foraminiferal marl, meaning of term__________________________________ VII-VIII

Fossils, miscellaneous, distribution of ___________________________ _______ IX

G 

Gastropods, environment ot....-.-.--,...-------------^-------------------- IX

Glacial marine deposits, age of__-__---___-_-----_---__-_----------------_---_- VII

features of.---_----------.- —--------------------------------------——— VII

glacialis, Krithe-.- ——- — — — — ---.--------------------------- 97,99,pi. 19

Glass shards, occurrence and character of___-_-____-_--__----_------_.---_-— VIII

Globigerinaooze, meaning of term. ________ ___________________________ VII-VIII

Grain size of sediments___________-_--____-__----------_----_----------------- VIII

H 

hamatum, Cytheropteron____.________________________________________ 97,101,pl. 19

Hemicythere.-------------------------------------------------------------- 100

sp...... — - — — —— — ———— — ——— — —— — - — - — — - 97

inflatum, Cytheropteron_.____________________________________________ 97,101,pl. 19

Introduction to complete report— — — —— — — — — —— — — — —— XIII-XV

jonesi Cythereis.———— ——— ——.—— —— ——— ~ ————— 97,101,103,pi. 19

K 

Krithe.....—— - — — -------- —— ---------.------ — - — — — - 99-100

bartonensis_-_______-__-_---___.---_____---___-------_----_ 97,99,101,103,pi. 19

glacialis..- — — — — - — -——- — — — - — - — — — - — ---— 97, 99, pi. 19

tumida___ _____________ ___________________ ______________________ 97,99-100, pi. 19

Lithologic zones in cores, correlation of_ ______________________________________ VII

Lithology and geologic interpretations_ _ _______________-_____------______ VII-VIII

Location of regionstudied____________________--______. _______________ VTI, XI, XIV

M 

Macrocypris_ — — — — .__- — - — _—_ — — - — — -_ — — _- -____ ---------

minna— —. — ..—.——- --------------- - - ------- 95,97,98,

Marl, foraminiferal, meaning of term________________________---_-.___-- VII

Mediterranean Sea, sediments in, significance of ________________________ XIII

minna, Macrocypris__ _____________-_-__-__ — -___ — ---__--_-____-_-_- 95,97,98,

miranda, Pourtalesia______________-_________-______------__----_--------- — —

Mollusca. ———— — — —— _- — —— _ — — — — — - — — — — — —— —

mucronalatum, Cytheropteron______________________________________ _ 97,102,

Mud-feeding organisms, role of— _ — — — - — - —-- — - — — — — — — — - — — —

Myodocopa__-_-.______--_____----_--_-__--__-----_----__-_---_- _____._ ———

95,98 

pi. 19 

-VIII

:-xiv

pi. 19 

IX 

IX

pi. 19 

VII

N

Nesidea,

O 

obtusata, Bythocypris._________________________________________________ 97,98,pi. 19

Ophiuroids, association of_______--_______--____------___---_-__------_-_--- IX

orbicularis, Polycope________________________ ___________ _________ _ 95, 97-98, pi. 19

Organic content of sediments___- -______-_-_ ___________-_____----____-_-___ IX-X

Ostracoda, age of— — — — — — — — — —— — —— — — — —— — — — — — — — — 103

ecology and distribution of _____________________ _. _ _ _ IX, 95-97, 103-104, pi. 18

systematic descriptions of-— — _ — — — — — — — -_— — _-- — — — — — — — 97-103

Outline, of complete report-______----__ — ---____ — _-___-_ — _-- — — -___ — — — -_ V

Palagonile, character and occurrence of—— — — — — ——___ — _ — __ —— — ___-_ V1H

Paracytherois- —.___-----__-----------_------------------------------------ 102-103

flexuosa ___________ ___________________________ 96,97,102-103, pi. 19

producta—-- —— — -- — - — --- —--- — - — - — --- — - 96,97,103, pi. 19 

Paradoxstoma _._____---__-_--_--------__-__----------_---_---_-_.------------ 103

ensiforme-...______ _________________ ____.________-_____.-____-.. 97,103,pi. 19

XVII
XVIII INDEX

Page 

Pelecypods, environment of..-.________-.___.___-------- IX

Piggot, C. S., coring device designed by---_.__--_---_-_-_-__- ..... VII, XIV-XV

foreword by..._.—.__....—...__.— „.——_..— — .__...._..__ XI-XII 

Plankton, relation of, to organic content.._-..---_.-.__..____.__. X 

Platycopa..__..__________----....__...___...._______.. 95 

Podocopa—.--..---.----.._..-.-—---.----.---.--.----..---..---.--- 95,98-103 

Polycope.------____.--.—--...-—.--.._-..--.---..---........---... 97-98

orbicularis___________________________.___ 95,97-98, pi. 19 

Polycopidae.-______._______________.___________ 97-98 

Pontocypris------____..-____— —__.-.-_---------____ ____.. 95

Porosity of the sediments_____________________________ VIII 

Pourtalesiamiranda_--------__—_---------_-__.-_-_.__—_ IX

producta, Paracytherois..__-...--__------------------------- 96,97,103,pi. 19

Pseudocythere________________________________ 96,102

caudata—__.._.....____............_............. 95,96,97,102, pi. 19

Pteropod shells, distribution of——...................................... VIII, IX

R

Radium, concentration of, on ocean bottom.-.—...... —........______ XI

Rare elements, spectroscopic tests for..______.._.__-..---.._.... VIII

Region sampled, extent of.-..._______________-------__, VII, XI

reniformis, Bythocypris__________.___________________ 98

Sampling and examination of cores, methods of...—_--...- —. —— — XIV-XV

Sediments, age and correlation of--. — — -- — - —. ——_ — — - ———_ — — —.- VIII

grain size of._— ———. —— - —— -———————————————————— VIII

organic content of——————... —. — — -. — — — ——— - ——. ——— —— IX-X

Selenium content of sediments——..-.. — ——.. — ——— —— —— —— -.———— X

Spectroscopic tests of sediments—------------ — _ —— — ------ —— ------—— VIII

Summary of complete report__ _..._..-.----..- — -... — ....-. — — -. VIII-X

T

Temperature, relation of type of sediment to————...—.——.—— VII, VIII, X 

Texture of sediments, relation of, to organic content.... —— — -——...- ———— X

tuberculata, Cythereis—-----------------------------_-----_-.. 97,100,pi.20

tumlda, Krithe—————— — ——————— — ——— 97,99-100, pi. 19

U 

Uranium, in ocean sediments——„.—..-—————...— .. ——.—-——— XI

Volcanic ash, composition and distribution of____..-.-.---.- — -...—. VII 

Volcanic glass, occurrence and character of—..-.._ — -..----.-—--.------ — .. VIII

Z 

Zones represented in the cores, correlation of- — ------ ——————.—— VII