US.

Foraminifera From

 \m

Onotoa Atoll 

Gilbert Islands

GEOLOGICAL SURVEY PROFESSIONAL PAPER 354-H

I

ft
Foraminifera From 

Onotoa Atoll 

Gilbert Islands

By RUTH TODD

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 354-H

Ecologic study of Recent assemblages from 

beaches , reefs, and shallow lagoon floor

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1961
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

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

Washington 25, D.C.
CONTENTS

Page

Abstract_________________________________________ 171

Introduction._ _____________________________________ 171

Material studied____________________________________ 171

Locality data_._________________________________ 173

Fauna___________________________________________ 176

Wet samples_______________________________________ 181

	Page 

Examination of fish contents.________________________ 182

Foraminifera from pits._______ ______________----__ 184

Local distribution of Calcarina and Baculogypsina _ _____ 186

Notes on selected species.- ________________________ 186

References cited-___________________________________ 188

Index.____________________________________________ 189

ILLUSTRATIONS

[Plates 22-25 follow index]

PLATE 22. Recent benthonic Foraminifera from Onotoa Atoll.

23. Recent benthonic Foraminifera from Onotoa Atoll.

24. Recent planktonic Foraminifera from Onotoa AtolL

25. Foraminifera sands from Onotoa Atoll. 

FIGURE 40. Map of Onotoa showing locations of samples studied and major occurrences and relative abundance of Calcarina

and Baculogypsina. _-_________________________________--__-____-__-_-__-------------------_------- 172

41. Diagrammatic sections of 7 dug pits on the northern main island of Onotoa Atoll-__---_-----_-------------- 185

TABLES

TABLE 1. Distribution of Recent Foraminifera of Onotoa Atoll______________.________________________-_-_--__.-----_ 177

2. Occurrence of Foraminifera in stomach and gut contents of fish from the lagoon at Onotoa Atoll- _ .____..-___-_ 183

in
SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS

Bv RUTH TODD

ABSTRACT

The distribution of 168 species and varieties of smaller Foraminifera is recorded within the lagoon and on the reefs and 

beaches of Onotoa Atoll as represented by 33 surface samples 

and 23 pit samples. Nearly all the species are well known in 

shallow-water sediments of the tropical Pacific; 7 are indeterminate; none are described as new. The lagoon collecting localities 

were all but one from depths no greater than 20 feet, and mostly 

from areas protected from the open ocean. Preservation in 

alcohol of 24 samples permitted a staining process to be used and 

an estimate to be made of the very small live-dead ratio, and 

determination of the living places of certain of the species.

Recognition of two major distinctive habitats- (a) reef surfaces and their adjacent slopes and (b) limesand bottom of the 

lagoon is based in part on the relative abundance of species 

and in part on the presence of live (stained) specimens.

Four species Calcarina spengleri, Baculogypsina sphaerulata, 

Amphistegina madagascariensis, and Marginopora vertebralis 

make up quantitatively most of the foraminiferal material in 

the reef sediments. Major foraminiferal constituents of the 

lagoon sediments are, in quantitative order: Amphistegina 

madagascariensis, Heterostegina suborbicularis, Marginopora 

vertebralis, and Elphidium striato-punctatum. Quantitatively 

insignificant because of their smaller size, but common or abundant in most samples, are many species of miliolids and several 

species in each of the following families: Textulariidae, Peneroplidae, Buliminidae, Discorbidae, Cyinbaloporidae, Anomalinidae, and Planorbulinidae. Globigerinids are present, but only 

rarely, and appear to have come in from the open ocean through 

breaks in the reef. Seventeen other families are represented 

mostly by rare or scattered occurrences.

Stomach and gut contents of 22 fish were found to contain 

Foraminifera tests nearly as varied as the naturally occurring 

fauna. The fact that most of the individual fish did not contain 

as great a variety as the composite of all the fish suggests a 

rather localized feeding area for each fish.

Seven pits provide short sections a maximum of 10 feet into 

the sediments that make up the northern main island. These 

sediments are interpreted as beach sands overlying and transitional to reef flat deposits.

INTRODUCTION

Onotoa Atoll is a "dry" atoll (referring to its rainfall 

[Cloud, 1952, p. 10-15]) in the southern part of the 

Gilbert Islands. It is elongate northwest-southeast 

and bordered nearly continuously on the northeast 

(windward) and south sides by narrow islands but either 

open to the ocean or protected by discontinuous living

coral reefs on the southwest side (fig. 40). Its dimensions are roughly 12 miles long and 4 to 5 miles wide. 

Latitude and longitude at its northwestern end are 

1°46' S. and 175°30' E. Its physical description may 

be found in a preliminary report by Preston E. Cloud, 

Jr. (1952), who in 1951 made the collections upon 

which this study is based.

Acknowledgments. I am indebted to Preston E. 

Cloud, Jr., for making available the well-documented 

material and to John E. Randall for the identifications 

of the fishes studied. For helpful suggestions and discussions I am grateful to Preston E. Cloud, Jr., and to 

Richard Cifelli. Invaluable help in preparation of 

material and tabulation of results was received from 

Doris Low. The illustrations of the individual specimens of Foraminifera were made by Elinor Stromberg.

MATERIAL STUDIED

Samples were studied from the following areas of 

Onotoa Atoll:

(1) Area open to ocean on west (leeward) side of atoll 

(7 samples from depths between 3 and 18 feet);

(2) Lagoon:

(a) Southern part (8 samples from depths between 6 and 17 feet, with 1 exception, 

f 11683 [GOC-55] collected from 48 feet)

(b) Central and northern part (7 samples from 

depths down to 20 feet);

(3) Reef areas (3 samples from leeward side of atoll 

and 2 from windward);

(4) Southern part of atoll (4 samples of fine sediment 

and incipient beachrock);

(5) Islands along the east (windward) side of atoll

(a) Beach sands (4 samples)

(b) Material from pits having depths from 20 

inches to 11% feet. The pits start in beach 

sands, in which many of the specimens are 

severely corroded (13 samples), and penetrate through progressively richer transitional sediments (7 samples) into sediments of a reef-flat horizon (3 samples).

171
172 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

EXPLANATION

O

Foraminifera locality, showing percentage of occurrence of Calcarina 

and Baculogypsina

t 

Church

Maneaba

ge meetinghouse

FtGUEE 40. Map of Onotoa showing locations of samples studied and major occurrences and relative abundance of Calcarina and Baculogypsina.
FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 173

LOCALITY DATA

The following locality and sample descriptions, taken 

from P. E. Cloud's field notes, are arranged in order of 

their U.S. Geological Survey Foraminifera locality 

numbers. They include pertinent details of the various 

environments from which the Foraminifera from Onotoa 

Atoll, Gilbert Islands, were derived.

U.S.G.S. loc. 

No.

fl!639-fll643.

fl!639.

f 11640.

fl!641.

fl!642.

fl!643.

fl!644-f11649.

Field localities and descriptions

GOC-1. Southern part of northern main 

island, about 1,100 ft S. 41° E. from east 

(inshore) end of lagoon-side jetty at Government Station and 325 ft inshore from sea beach 

along line bearing S. 87° W. at Pacific Science 

Board campsite. Pit in which water level 

fluctuated with tide. Pit section in descending order, with unit thicknesses, is:

GOC-1 A. 99+ percent medium-grained Calcarina sand, dark brownish gray from organic 

matter. Roots very abundant, up to seveneighths of an inch in diameter. Foraminifera 

worn or eroded by organic acids. Subaerial 

accumulation?. Top 9-10 in.

GOC-1B. 99+ percent medium-grained darktan Calcarina sand, abruptly gradational to 

f 11639 (GOC-1 A). Sample f 11640 differs 

only in organic content, abundance of roots, 

and good preservation of Calcarina, suggesting only slight transportation. Roots moderately abundant, as much as one-half of an 

inch in diameter, cutting off abruptly at 

base. Subaerial accumulation?. Thickness, 

16-17 in.

GOC-1C. Similar to fl!642 (GOC-1D), which 

follows, but has alternating layers of semiindurated to indurated material. Basal 1-4 

in. indurated. Roots rarely extend into unit 

C. Probably deposited along beach near 

reef flat. Thickness, 7-10 in.

GOC-1D. Weakly indurated to nonindurated 

medium-grained limesand, 80 ± percent wellpreserved Calcarina and 20 ± percent other 

Foraminifera and detrital CaCOs, much of 

it quite fine grained. Other Foraminifera 

include Marginopora. Color is light tan to 

flesh. Thickens where fl!641 (GOC-1C) 

thins and unit C apparently represents incipient beachrock at top of unit D. No 

roots. Probably deposited along beach near 

reef flat. Thickness, 14-17 in.

GOC-1E. Zone of Heliopora. About 70 percent blue coral of which much may be but 

none is certainly in position of growth; 30± 

percent interstitial limesands are coarse to fine 

grained, light tan to flesh, of detrital CaC03 

and Foraminifera. MarginQpora abundant; 

Calcarina common; echinoid spines occasional. Interpreted as reef-flat horizon, built 

up to about low tide level and then overrun 

by beach of f 11642 (GOC-1D). No roots. 

16 in. above watermark. Thickness, 25 in.

GOC-2. Southern part of northern main 

island, about 940 ft S. 25° E. from east (inu.s.o.s. loc.

No.

f11644.

f11645.

f 11646.

f11647.

f 11648.

f11649.

fl!650-fll653.

f11650.

f11651.

None.

Field localities and descriptions

shore) end of lagoon-side jetty at Government Station and 660 ft inshore from sea 

beach along line bearing S. 87° W. at Pacific 

Science Board campsite. Pit similar to 

GOC-1. Pit section in descending order, 

with unit thicknesses, is:

GOC-2A. Medium- to fine-grained limesand, 

dark brownish gray from organic matter. 

Worn Calcarina about 60 percent; remainder 

of detrital fines. Roots uncommon. Some 

stones as much as three-fourths of an inch in 

diameter. Top 5 in.

GOC-2B. Medium-grained limesand. Worn 

Calcarina about 70 percent with occasional 

pebbles as much as three-eighths of an inch 

in upper 7 in. Up to 95+ percent worn 

Calcarina below. Remainder is detrital 

CaC03 . Tan to flesh colored; darker above 

than below. Roots abundant, as much as 

three-eighths of an inch in diameter. Thickness, 19 in.

GOC-2C. Loose CaC03 gravel composed of 

50 percent CaCOs pebbles as much as 2J4 in. 

long and 50 percent worn Calcarina and 

detrital CaCOs. Roots abundant, as much 

as one-fourth of an inch in diameter. Thickness, 11 in.

GOC-2D. Strongly indurated flesh-colored 

granule sandstone, of varied detrital CaCOs. 

One loose sand layer 2-4 in. from base. Roots 

very rare. Thickness, 15 in.

GOC-2E. Very fine grained flesh-colored 

detrital limesand. No roots. Thickness, 

6 in.

GOC-2F. Zone of Heliopora. Essentially 

same as fl 1643 (GOC-1E). No roots. Reef 

flat horizon? Thickness, 51 in.

GOC-3. Southern part of northern main 

island, about 870 ft S. 3° E. (true) from east 

(inshore) end of lagoon-side jetty at Government Station and 340 ft inshore from lagoon 

beach along line bearing N. 87° E. through 

Pacific Science Board campsite strip. Pit 

similar to GOC-1 and GOC-2. Pit section 

in descending order, with unit thicknesses, is:

GOC-3A. Dark-brownish-gray organically enriched limesand similar to f 11644 (GOC-2A). 

Roots common. Top 8 in.

GOC-3B. Similar to f 11650 (GOC-3A) but 

with less organic matter and only dark-tan 

to light-brown color. Roots abundant as 

much as one-half of an inch in diameter. 

Subsoil. Thickness, 6 in.

GOC-3C. Medium-grained flesh-colored (pinkish-tan) limesand with occasional granules 

and small pebbles (to one-half of an inch in 

diameter). Mostly 90 percent worn and 

smooth Calcarina but with occasional Foraminifera of other sorts, echinoid spines, algal 

fragments, small mollusks, and detrital 

CaCOs. Many roots, upper part. Thickness, 38 in.
174 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

U.S.O.S. loc.

No. Field localities and descriptions

f 11652. GOC-3D. Similar to GOC-3C but has fairly 

numerous pebbles (one-half of an inch maximum diameter) and granules; small gastropods relatively common, and Marginopora 

common. Thickness, 20 in.

None. GOC-3E. Pinkish-gray granule gravel of 

fragmentary ramose calcareous algae with 

interstitial Calcarina sand (worn smooth). 

Thickness, 10 in.

fl!653. GOC-3F. Similar to fl!652 (GOC-3D).

Thickness, 40 in.

None. GOC-3G. Zone of large head-forming crustose 

corallines and occasional astraeiform corals 

and interstitial sand like f 11652 (GOC-3D) 

and f 11653 (GOC-3F). Only algae and 

corals sampled. Thickness, 8 in.

None. GOC-3H. Similar to fl!652 (GOC-3D) and 

f 11653 (GOC-3F). (Field observation, no 

sample taken.) Thickness, 8 in.

fl!654-f 11655. GOC-4. North-central part of northern main 

island, about 1,000 ft east-northeast from 

Taneang-Tekawa Maneaba. Section in area 

of fine clastic limesand that makes finegrained loamy soil at this place dry. Pit 

section in descending order, with unit thicknesses, is:

f 11654. GOC-4A. Very fine grained brownish-gray 

(from organic matter) limesand; grades down 

to fl!655 (GOC-4B). Roots common, as 

much as five-eighths of an inch in diameter. 

Top 10 in.

f 11655. GOC-4B. Pinkish-yellow clastic limesand 

mostly fine grained, with <10 percent 

Calcarina but local patches contain abundant 

Calcarina. Only occasional roots in upper 

part. Thickness, 26 in.

fl!656. GOC-5. North-central part of northern main 

island, about 1,700 ft northeast from Taneang-Tekawa Maneaba. Area of pebble coral 

gravel with interstitial limesands. Stonv 

and hard to dig. Dug down only 20 in., of 

which top 10 in. is organic-rich, brownishgray soil with plentiful roots. Lower 10 in. 

pinkish yellow.

fl!657-f 11659. GOC-6. North-central part of northern main 

island, about 2,400 ft north-northeast from 

Taneang-Tekawa Maneaba. Section in area 

of fine clastic limesands locally with thin 

gravel veneer at surface and locally of old 

dune sand material near shore. Pit section 

in descending order, with unit thicknesses, 

is:

f 11657. GOC-6A. Organic-rich, dark-gray-brown limesand, 20 ± percent worn Calcarina, few small 

pebbles (as much as one-half of an inch in 

diameter), many small roots. Top 6 in.

f 11658. GOC-6B. Dark-tan limesand, 30-40 percent 

worn Calcarina, many roots as much as onehalf of an inch in diameter; no pebbles. 

Thickness, 10 in.

f 11659. GOC-6C. Flesh-colored medium-grained limesand, 10-25 percent badly worn Calcarina. 

Thickness, 14 in.

U.S.O.S. loc. 

No.

fl!660-fll661.

f11660.

f!1661.

fl!662.

fl!663-f11664.

f11663.

f 11664.

None.

fl!665.

fl!666.

fl!667.

fl!668.

Field localities and descriptions

GOC-17. Central part of northern main 

island, about 2,100-2,200 ft due east from 

Buariki Maneaba. Area of fine clastic limesilt 

on which water lies close to surface, hardpan tends to form, ground water is brackish, 

and soil is generally poor. Pit section in 

descending order, with unit thick-nesses, is:

GOC-17A. Fine medium-grayish-tan limesand 

and limesilt. Many roots as much as threeeighths of an inch in diameter. Few Calcarina. Top 9 in.

GOC-17B. Light-tan medium-grained limesand, 10-15 percent Calcarina. Roots mainly in top inch or two but some to bottom. 

Thickness, 15 in.

GOC-19. Beach sand on the northwest shore 

of islet of Nanntabuariki. Excellently preserved Baculogypsina and Marginopora 

washed in from adjacent reef flats to north 

and east.

GOC-20. Southern main island, section above 

beach just south of Otoae village Maneaba, 

lagoon shore. Section in descending order, 

with unit thicknesses, is:

GOC-20 A. Limesand, 20 ± percent Calcarina, 

scattered pebbles as much as 2 in long. Top 

24 in.

GOC-20B. Shell bed, limesand (50 percent 

Calcarina) matrix small Cardium most 

abundant. Goes laterally to a pebble gravel. 

Thickness, 6 in.

GOC-20C. Limesand, 40-50 percent Calcarina, occasional pebbles as much as 2 in long. 

Thickness, 15 in.

GOC-27. About 9,200 ft S. 72° W. from offshore end of Government Station jetty (on 

southern part of northern main island) just 

south of main passage out of lagoon (Rawa 

ni Karoro) where coral shoals known as Aon 

te Rabata begin to deepen. Collection from 

area where reef knolls and patches rise above 

the limesand bottom at 16 ft depth. Most 

specimens from a low coral patch about 14 

ft below the surface.

GOC-28. Slightly less than 4 miles N. 85° W. 

from Aiaki Maneaba in outer lagoon. Reef 

patches and knolls rising above limesand 

bottom (at 14 ft) to within 6 ft of water 

surface. Fish taken from on and near reef 

knolls and sediment taken from bottom.

GOC-29. About 1 mile S. 32° W. from Tekawa 

church at lagoon margin of south end of reef 

stretch known as Aon te Baba. Collection 

from reef patches rising above limesand 

bottom (at a depth of 9 ft reduced to mean 

low tide) to within 1 ft of surface. Much 

Halimeda, many sheetlike crustose corallines 

red on under sides. Limesand very fine to 

limesilt at centers of open areas.

GOC-30. Heliopora flat at south end of the 

northern main island. At +1 ft low tide, 

tops of living Heliopora and few Porites lobata 

seen were just flush with water surface.
FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 175

U.S.G.S. toe. 

No.

£11669.

fl!670.

fl!671-f 11672.

fl!671. 

fl!672.

fll673-f!1674.

£11673.

fl!674.

fl!675.

fl!676.

f 11677.

fl!678.

Field localities and descriptions

GOC-31. Southeast end of northern main 

island. Scrapings from green algal crust 

on inner flat of windward reef about midway 

out (east) on reef flat from center of cove at 

southeast end of island. Sediment-binding 

green algae are matted with Baculogypsina, 

Marginopora, and other Foraminifera.

GOC-33. About 7,100 ft S. 50° W. from 

Tekawa church at seaward edge of Aon te 

Baba reef north of main boat passage. Reef 

area is broad and irregular, fronted seaward 

by area of limesand 18 ft deep at midtide or 

about 15 ft reduced to mean low tide. (At 

collecting locality reef itself at general depth 

of 3 ft at mean low tide, with holes to depth 

of 8 ft at mean low tide.) Medium-grained 

limesand with ripple marks parallel to reef 

front. Slopes gradually seaward with offlying reef patches.

GOC-35. About 8,600 ft N. 18° W. from 

Tabuarorae Maneaba in 17 ft of water at 

mean low tide.

GOC-35a. South bottom sample.

GOC-35b. North bottom sample. Area of 

many coral patches on limesand-gravel 

bottom. Anchored for first sample (f 11671 

GOC-35a) of limesand-gravel over an area 

richly floored with red bushy crustose corallines, but dragged anchor and drifted northwest about 100 yd where collected second 

bottom sample (£11672, GOC-35b) of relatively pure limesand.

GOC-36. Southeast end of reef area known as 

Rakai Ati (south side of big westward point 

of reef near center of atoll). A flourishing 

reef; collection from reef flat northeastward 

in shoal waters, from strip about one-half of 

a mile long running clear across the reef.

GOC-36a. Seaward or southwestward ±500 

ft is area of much coral in small and large 

patches with interspersed coarse limesand 

having a considerable gravel fraction of 

granule and pebble size.

GOC-36b. Lagoonward or northeastward 

±500 ft is mostly sand with scattered coral 

patches.

GOC-37. About one-third of the distance 

between the north point of the reef area 

known as Rakai Ati and the east end of 

Rakai Maneku, at inner part of point of reef 

that projects westward from near the center 

of Onotoa Atoll. Sediment sample taken from 

hole about 10-12 ft deep.

GOC-38. Lower beach at southwest corner of 

Tebaki, north end of northern main island. 

Sandy lagoon beach.

GOC-45. Area of Thalassia patches on coarse 

limesand bottom off northwest end of outer 

rib of elevated beachrock at north Tekawa, 

northwest Onotoa Atoll.

GOC-48. About 10,000 ft S. 62° W. from 

lagoon end of Government Station jetty at

U.S.G.S. toe. 

No.

fl!679.

£11680.

fl!681.

f 11682.

fl!683

fl!684.

fl!685.

Field localities and descriptions

north end of reefy shoal area known as Aon 

te Rabata. Coral patches rising to within 

5 ft of surface from lesser (30-50 percent of 

area) intervening areas of limesand bottom, 

12ft.

GOC-49. About 12,000 ft S. 63° W. from 

lagoon end of Government Station jetty, on 

the seaward side of the north end of a reefy 

shoal area known as Aon te Rabata, in patch 

reefs rising to within 6 ft of surface Limesand bottom at 18 ft deep.

GOC-51. About 3^ miles N. 31° W. from 

Tabuarorae Maneaba near center of Te 

Rawa ni Bao, a pass in south part of leeward 

reef. Collected from thickly set coral masses 

rising from 15 ft (sounded at low tide) of 

water to within about 8-10 ft of surface 

locally. Bottom of coral-algal rock anc' 

living corals and algae with minor pockets of 

very coarse limesand and calcareous gravel. 

Sediment sample taken in shoal area lagoonward in about 3 ft of water from hole containing coarse limesand and gravel.

GOC-52. About 12,000 ft N. 30° W. from 

Tabuarorae Maneaba at south end of Rakai 

ni Make, a reef area in southern part of 

leeward reef. Collected corals, algae, mollusks, and sample of coarse limesand and 

gravel, the latter from a hole in about 3 ft 

of water.

GOC-53. About 9,300 ft N. 30° W. from 

Tabuarorae Maneaba in southern part of 

Te Rawa Tekatobibi, a pass through south 

end of leeward reef. Collected from coral 

patches and knolls rising to occasional maximum of within 4 ft of surface from a bottom 

sounded at 18 ft.

GOC-55. About 13,400 ft S. 75° W. from 

Aiaki Maneaba in deep central part of the 

lagoon. Impalpably fine limemud from 

bottom of low scattered dead and living 

coral patches on intervening limemud and 

limesand about 30-40 percent sediments and 

60-70 percent coral.

GOC-56. About 8,300 ft S. 76° W. from 

Aiaki Maneaba on reef patch in the central 

lagoon. Complex mass of living coral 

with patches of limesand and fine gravel on 

surface, perhaps 150-200 yd in diameter, 

rising from surrounding bottom of ± 18 ft. 

Depths on knoll 4-10 ft at mean low tide, 

with coral heads rising to within 1 ft of 

surface. Sediment sample from mean low 

tide depth of ±6 ft.

GOC-57. About 7,500 ft S. 80° W. from 

Aiaki Maneaba on reef patch in central 

lagoon. Habitat, bottom types, and depth 

range similar to f 11684 (GOC-56), but much 

more limesand and less coral. Depth of 

sediment sample at ±6 ft at mean low tide 

datum.
176 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

U.S.O.S. loc.

No. Field locations and descriptions

f 11686. GOC-58. About 3,600 ft S. 80° W. from 

Aiaki Maneaba on reef patch in central 

lagoon. Generally similar to f 11684 (GOC56) and f 11685 (GOC-57) but smaller and 

deeper and contains even less coral than 

f 11685 (GOC-57). Bottom at ±10 ft at 

mean low tide datum, with patchy coral. 

Collected bottom sample at 15 ft mean low 

tide datum from lim'esand slope leading off 

to slightly deeper water.

f 11687. 51-L-8. Southeast end of Tabuarorae islet 

corresponding to Aontebeke land area. 

Weakly bonded limesand along beach.

fl!688. 51-L-9. Southwest end of Mangaia land area, 

Tabuaurorae islet. Low, narrow northtrending ridge in area of lush vegetation, 

apparently most easterly of a set of older 

dunesand ridges ±500 ft long, about 60 ft 

across from intertrough to intertrough. Only 

one of set that seems phosphatic.

f 11689. 51-S-5. Central Tabuarorae islet. West end 

of tidal flats encircled by islet.

fl!690. 51-S-6. Tabuarorae islet. Near center of 

north arm of tidal flats encircled by islet.

fl!691. 51-S-7. About 4,400 ft N. 86° W. from 

northwest corner of Abanekeneke, sediment 

taken in about 14 ft of water at mean low 

tide datum.

fl!692. 51-S-8. About 1,400 ft S. 60° W. from lagoon 

end of Government Station jetty. Drag 

sample of limesand bottom between sparse 

dead and living coral, taken in about 9 ft of 

water at mean low tide datum.

f 11693. 51-S-9. About 4,200 ft S. 79° W. from lagoon 

end of Government Station jetty. Fine 

limesand bottom at 20 ft depth at mean low 

tide datum. Patches of growing coral 

mostly to about 10-15 ft in diameter anr 

only 1-2 ft above bottom.

f 11694. 51-S-10. About 3# miles N. 30° W. from 

Tabuarorae Maneaba. From coarse- to 

medium-grained limesand bottom about 10 ft 

deep with coral pinnacles rising to within 6 ft 

of surface.

fl!695. 51-S-ll. About 4,600 ft S. 65° W. from 

lagoon end of Government Station jetty. 

Limesand bottom of reentrant or depression 

in large lagoon reef patch.

f 11696. 51-S-12. West side of Tebaki, northwest 

Onotoa Atoll. Center of clean limesand 

area between southwestward extending limesand spits.

FAUNA

A total of 168 species and varieties have been found 

in the Onotoa samples. In table 1 the samples are 

grouped, according to similarity of environment, in the 

following categories:

1. Area open to ocean on west (leeward side)

2. Lagoon

3. Reef areas

4. Islands along east side of atoll.

In the last category are included both modern beach 

sands and material from a series of dug pits inshore 

from the sea beach. Samples from the pits are grouped 

according to similarity of composition and in order 

of increasing variety of species. With this arrangement, the samples fall into three subdivisions: those 

interpreted as beach sands, those interpreted as reef 

flat sediments, and those transitional between these two 

types of deposits.

As the Onotoa species are nearly all well known and 

well illustrated (Cushman, Todd, and Post, 1954; Todd, 

1957; Todd and Low, 1960), complete formal descriptions are not included in this report and only a selected 

few are illustrated. In a later section, certain species 

that are not found in these three Professional Papers 

are discussed and selected references included for them.

Major constituents of the Onotoa fauna are:

Amphistegina madagascariensis d'Orbigny

Baculogypsina sphaerulata (Parker and Jones)

Calcarina spengleri (Gmelin)

Elphidium striato-punctatum (Fichtel and Moll)

Homotrema rubrum (Lamarck)

Heterostegina suborbicularis d'Orbigny

Marginopora vertebralis Blainville

Besides these, the following species, although they make 

up negligible amounts of the population, are found in 

most of the samples except the beach sand:

Acervulina inhaerens Schultze

Cibicidella variabilis (d'Orbigny)

Cornuspira planorbis Schultze

Cymbaloporetta bradyi (Cushman)

C. squammosa (d'Orbigny)

Elphidium advenum var. dispar Cushman

E. crispum (Linn£)

Gaudryina (Siphogaudryina) rugulosa Cushman

Haddonia torresiensis Chapman

Neoconorbina patelliformis (Brady)

Planorbulina acervalis Brady

Pyropilus rotundatus Cushman

Quinqueloculina polygona d'Orbigny

Reussella simplex (Cushman)

Rosalind candeiana d'Orbigny

Schlumbergerina alveoliniformis (Brady)

Siphogenerina raphana (Parker and Jones)

Spirolina arietina (Batsch)

Spiroloculina angulata Cushman

Tretomphalus concinnus (Brady)

T. planus Cushman

Triloculina irregularis (d'Orbigny)

T. oblonga (Montagu)

The remaining 138 species and varieties are rare for 

the most part, and their occurrences are scattered or 

single occurrences. Among them, however, are a few 

species whose distribution shows a restricted, and possibly significant pattern.
TABLE 1. Distribution of Recent Foraminifera of Onotoa Atoll 

[A indicates abundant; C, common; R, rare. Symbol printed in boldface indicates presence of live specimens]

Hy peramminidae :

Lituolidae:

Textulariidae:

Verneuilinidae:

(Siphogaudryina) rugulosa Cushman (pi. 25, fig. 5b) _

Valvulinidae:

Miliolidae:

Massilina planata Cushman. ___ .. ___ . __ __ ...

Area open to 

ocean on west 

(leeward side)

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R

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553580 O 61-
180 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

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FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 181

The species Textularia joliacea Heron-Alien and 

Earland, with its variety oceanica, appears to be restricted to the central deeper part of the lagoon where 

the bottom is covered by fine to coarse limesand between 

patches of coral. Streblus beccarii (Linne) is a large 

robust form unknown in typical form in the Marshall 

Islands but is found fairly commonly around Saipan 

Island. At Onotoa Atoll it is present in some of the 

lagoonal sediments. It probably is not a reef dweller. 

The rare occurrences of Bolivinella folium (Parker and 

Jones) are all from limesand bottom in the central part 

of the lagoon.

Examples of the Foraminifera typical of the limesand 

bottom of the lagoon are illustrated on plate 25, figures 

4-6.

In general, the Onotoa fauna shows rather close 

correspondence in species composition to the faunas of 

other areas of the central Pacific. Comparisons with 

shallow-water faunas around Saipan, Mariana Islands, 

(Todd, 1957), and inside the lagoons of four atolls 

(Bikini, Eniwetok, Rongelap, and Rongerik) in the 

northern Marshall Islands (Cushman, Todd, and Post, 

1954) are of interest. At Saipan the material was 

collected from depths mostly not greater than 38 feet 

depths comparable to those at Onotoa which were 

mostly shallower than 20 feet. In the Marshall Islands 

most of the samples came from depths greater than 60 

feet. No striking differences in fauna were observed 

between Saipan and Onotoa when the rarer occurrences 

from each area are left out of consideration. In the 

Marshall Islands, on the other hand, where the material 

came from significantly greater depths than did the 

Onotoa material, three species that are unknown at 

Onotoa are present with more than scattered occurrences. Their absence at Onotoa may signify an upper 

depth limitation for them, somewhere between 20 and 

60 feet. The species are Operculina ammonoides 

(Gronovius), Calcarina hispida Brady, and Anomalinella rostrata (Brady).

WET SAMPLES

Twenty-four of the Onotoa samples were treated 

with alcohol when collected in 1951 and preserved wet 

in order that distinction between living specimens and 

empty tests would be possible. By this means an estimate of which species actually lived in various locations 

and which species may have been deposited there as 

empty tests could be made.

In the spring of 1957, after approximately 6 years, 

the samples were processed by staining in rose bengal 

solution as described by Walton (1952, p. 58), Relatively few specimens (such as of the order of 1 percent) 

gave a positive reaction to the stain. It is unknown 

whether or not a 6-year interval between collection and

processing may affect the apparent live-dead ratio. To 

me it seems doubtful that it had an appreciable effect 

on the Onotoa samples, as the stained specimens 

observed were mostly very clearly and unmistakable 

stained.

On table 1, the record of live specimens is indicated 

by the abundance symbol being printed in bold face. 

An A or C printed in bold face does not of course mean 

that the live specimens were abundant or common, but 

merely that among the abundant or common specimens 

were some live (stained) ones.

With the stained individuals forming so small a 

percentage of the total specimens present, it is not 

unreasonable to assume that evidence for these live 

specimens would be frequently missed. This assumption may be the explanation for the "lack" of stained 

specimens of a particular species in certain samples 

where unstained specimens of that species are common 

to abundant. The following common to abundant 

species are those of which living specimens probably 

occurred but were missed in the samples studied.

Amphistegina madagascariensis d'Orbigny 

Baculogypsina sphaerulata (Parker and Jones) 

Calcarina spengleri (Gmelin) 

Cymbaloporeita bradyi (Cushman) 

C. squammosa (d'Orbigny) 

Elphidium striato-punctatum (Fichtel and Moll) 

Heterostegina suborbicularis d'Orbigny 

Marginopora vertebralis Blainville 

Schlumbergerina alveoliniformis (Brady) 

Spirolina arietina (Batsch)

The assumption that specimens of the foregoing species 

lived where they occur commonly to abundantly seems, 

therefore, a safe one.

The two major distinctive habitats that are recognizable at Onotoa on the basis of the relative abundance 

of species in the sediments are the surfaces and slopes 

of reefs and the limesand bottom of the lagoon. Presence 

and absence of stained specimens (that is, collected as 

living individuals) of certain species in samples from 

these two areas confirms the distinction between these 

two habitats. The major inhabitants of reef surfaces 

and the slopes adjacent to reefs seem to be (in order of 

abundance):

Calcarina spengleri (Gmelin) 

Baculogypsina sphaerulata (Parker and Jones) 

Amphistegina madagascariensis d'Orbigny 

Marginopora vertebralis Blainville 

Cymbaloporetta bradyi (Cushman) 

C. squammosa (d'Orbigny)

The major inhabitants of the limesand bottom of the 

lagoon seem to be (in order of abundance):

Amphistegina madagascariensis d'Orbigny 

Heterostegina suborbicularis d'Orbigny 

Marginopora vertebralis Blainville 

Spirolina arietina (Batsch)
182 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Cymbaloporetta bradyi (Cushman)

C. squamosa (d'Orbigny)

Elphidium striato-punctatum (Fichtel and Moll)

Schlumbergerina, alveoliniformis (Brady)

Minor inhabitants of the limesand floor include four 

large arenaceous species, Valvulina davidiana Chapman, 

Haddonia torresiensis Chapman, and the two large 

species of Oaudryina (Siphogaudryina) a variety of 

miliolids; the peneroplids Peneroplis ellipticus d'Orbigny 

and Sorites marginalis (Lamarck); several buliminids 

including Reussella simplex (Cushman) and a few 

species of Bolivina; a few discorbids including several 

species of Rosalina and Neoconorbina; several species of 

Elphidium; a few forms belonging in the Cymbaloporidae (Pyropilus rotundatus Cushman and two species 

of Tretomphalus) and several species of the families 

Anomalinidae and Planorbulinidae that are usually 

attached forms.

In addition, the following species are present as live 

specimens in the lagoon but seem to be locally restricted, 

their local restriction being obvious from the limited 

distribution of their empty tests as well as of stained 

specimens:

Buliminoides williamsonianus (Brady)

Cassidulina minuta Cushman

Epistomaroides polystomelloides (Parker and Jones)

Epistominella tubulifera (Heron-Alien and Earland)

Placopsilinal sp.

Poroeponides cribrorepandus Asano and Uchio

Siphoninoides echinatus (Brady)

Spirillina (several species)

Streblus beccarii (Linne)

Textularia dupla Todd

T. foliacea Heron-Alien and Earland

T. foliacea var. oceanica Cushman

As for the remaining 76 species present in the 24 wet 

samples, for which no evidence of living specimens was 

found, with but two exceptions the species are rare 

with scattered occurrences. One interpretation of these 

76 may be that the specimens did not live precisely 

where found and the empty tests were deposited there 

after having been washed in from another, probably 

nearby, location. However, the possibility of missing 

stained specimens, in assemblages where the species 

in question occurs rarely, is very great. Thus a second 

interpretation is that evidence of live specimens was 

missed in many of these rare occurrences.

The two exceptions where species were not rare are 

Spiroloculina clara Cushman and Homotrema rubrum 

(Lamarck). Specimens of Spiroloculina clara were 

probably washed into their collecting localities as 

empty tests. In Homotrema rubrum the red original 

color of the test would preclude recognition of any red 

stain if present. Furthermore, it is unlikely that 

broken-off fragments of such permanently attached 

forms as Homotrema would retain their protoplasm for

long. However, in other less firmly or less permanently 

attached forms, such as Planorbulina and Acervulina, 

staining proved that at least some of the detached 

specimens were still alive when collected.

EXAMINATION OF FISH CONTENTS

Stomach and gut contents of 22 fishes were examined 

for their Foraminifera, and many species were found in 

several of them (table 2). The fishes fall into five 

groups as follows:

Trigger fishes:

Nos. 2-4. Rhinecanthus aculeatus (Linnaeus)

8. R. rectangulus (Bloch and Schneider) 

5-7. Ralistapus undulatus (Park) 

20. Melichthys bunvia (Glinther) 

Surgeon fishes:

Nos. 16. Acanthurus gahhm (Forskal)

17. Ctenochaetus striatus (Quoy and Gaimard)

18. C. cyanoguttatus Randall 

Parrot fishes:

Nos. 9-15. Scarus sp. 

File fish:

No. 21. Cantherines sandwichensis (Quoy and Gaimard) 

Puffers:

Nos. 22, 24. Arothron nigropunctatus (Bloch)

From Cloud's observations in the field (written 

communication July 24, 1959), the feeding habits of 

these groups of fish are as follows: Trigger fishes and 

surgeon fishes browse mostly on algae and coral, but 

they also eat small echinoids and take in considerable 

amounts of the bottom sediment. The parrot fishes 

browse on algae, coral, and coral-algal rock, occasionally 

breaking off large chunks. The file fishes and puffers 

seem to eat mainly coral.

It can be seen from the occurrence table that a greater 

variety of Foraminifera species is found in the trigger 

and surgeon fishes (in which the habit of taking in 

bottom sediment is present) than in those fishes that 

ordinarily browse only on the various plants and animals that grow up from the lagoon floor.

In general, a larger proportion of attached forms are 

found in the stomach and gut contents than are found 

in the bottom sediments. In only one sample, however, 

was any foraminiferal material obviously bitten off by 

a fish: a large fragment of Planorbulinoides retinaculatus (Parker and Jones) found in one of the trigger 

fishes. Probably most of the specimens were taken in 

as a part of the bottom sediment incidental to the 

obtaining of other food. In some samples a large 

proportion of the specimens of Amphistegina still retain 

their light-green color and fresh appearance, suggesting 

they were living when taken in by the fish.

The composite fauna from the several fish examined 

is one characteristic of shallow conditions. The most 

abundant species is Amphistegina madagascariensis 

d'Orbigny, which is the dominant species in most
FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 183

TABLE 2. Occurrence of Foraminifera in stomach and gut contents of fish from the lagoon at Onotoa Atoll

Textulariidae:

Verneuilinidae:

Valvulinidae:

Miliolidae:

incisurd Todd

Ophthalmidiidae:

Parrina bradyi (Millett) .. ._._ .__.

Camerinidae:

Peneroplidae:

Buliminidae:

Spirillinidae:

Discorbidae:

Rotaliidae:

Elphidiidae:

Amphisteginidae :

Calcarinidae:

Cymbaloporidae:

Globigerinidae:

Anomalinidae:

Planorbulinidae :

Homotremidae:

Trigger fishes

aculeatus Rhinecanthus 

(Linnaeus)

2

X

X

X

X

X

X

X

X

X

X

X

X

X 

X

X

X 

X

X

3

X

X 

X

X 

X

X

4

X 

X

X

X

X 

X

Rhinecanthus rectangulus (Bloch and Schneider)

8

X

X

X 

X

X

Balistapus undulatus 

(Park)

5

X

X

X

X

X

X

X

X

X

X

5a

X

X

X

X

X

X

X

6

X

X

X

X

 -

X

X 

X 

X

X

X

7

X

X

X

X

X

X

X 

X 

X

X

X 

X

Melichthys buniva 

(Gunther)

20

X

X 

X 

X

X

X 

X

Surgeon 

fishes

gahhm Acanthurus 

(Forskal)

16

X

X

X

X

X

X 

X

X

X

X

striatus Ctenochaetus Gaimard) (Quoy and 

17

X

X

X

X

X

X 

X

X

....

Randall C. cyanoguttatus 

18

y

X

X

X

X

X

X

X

X

X

Parrot fishes

a

i

e 

$3

9

X

10

X

11

X

12

X

13

X

14

X

15

X

X

File 

fish

sandwichensis Cantherines 

and Gaimard) (Quoy 

21

X

X

Puffers

nigropunctatus Arothron 

(Bloch)

22

X

X

X

X

X

X

24

X

X

X

....

X

X
184 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

shallow waters of the tropical Pacific. The next most 

abundant species is Heterostegina suborbicularis d'Orbigny. Abundance of these two forms is known to vary 

greatly from place to place, possibly for reasons related 

to gregarious habit of Foraminifera. Likewise, their 

abundance varies greatly in the stomach and gut 

contents. Fish No. 15, for example, contained more 

specimens of Heterostegina than of any other genus of 

Foraminifera.

Miliolids are much more abundant than buliminids in 

the samples under discussion. Peneroplids (except for 

Marginopora vertebralis Blainville, a species that appears 

to live more abundantly on the reef flats than on the 

bottom of the lagoon) are rare, and arenaceous forms 

are almost completely missing. Globigerinids are also 

very rare in the stomach and gut contents. Quite a 

large proportion of the specimens found in the stomach 

and gut contents are attached forms, such as Neoconorbina, Rosalind, Cymbaloporetta, Cibicides, Cibicidella, Acervulina, Planorbulina, Planorbulinoides, and 

Homotrema.

In the bottom sediments, specimens of Tretomphalus 

are found in fair abundance; those with float chambers 

accompanied by rather large numbers of the Rosalinastages without float chambers. The morphogenetic 

relationship between these two forms was demonstrated 

and clearly illustrated by Myers (1943, pi. 3), who also 

presented other observations regarding the biology and 

ecology of the genus Tretomphalus. Myers concluded 

(1943, p. 21) that the planktonic stage of Tretomphalus 

was very brief and lasted usually no more than 18 hours 

unless the specimen became encrusted with minute 

algae or other organisms, in which case it would remain 

afloat indefinitely. If not thus supported, a planktonic 

specimen would promptly sink to the bottom after the 

escape of the gametes through the large pores in the 

spherical float chamber. Thus in a tropical environment where there is no marked seasonal temperature 

fluctuation and where the water temperature of about 

29° C is well above the 18° C observed to be the minimum temperature for development of the floating stages 

of Tretomphalus (Myers, 1943, p. 22), a steady supply 

of the fragile specimens with float chambers might be 

expected to be constantly added to the bottom 

sediments.

The Rosalina stages of Tretomphalus, however, presumably did not live in the bottom sands or muds but 

attached to algae or any sort of stemmed structure and 

thus could have been obtained by the fish as it browsed. 

Nevertheless, most of both forms of this genus were 

probably taken in as a part of the bottom sediment 

rather than in the process of browsing on algae or coral 

(Cloud, 1952, p. 26; 1959, p. 398-399, pis. 130, 131).

The trigger and surgeon fishes, most of which contain

a large proportion of reef-dwelling Foraminifera, such 

as Baculogypsina, Calcarina, and Marginopora, may be 

interpreted as being frequenters of reef flats and reef 

fronts. Other fishes, whose stomachs are free or nearly 

free of those large genera, probably fed mostly in patch 

reefs and sandy areas. The observation that certain 

fish had consumed large proportions of one or the other, 

but usually not both, of the two major genera (Calcarina and Baculogypsina} that inhabit the reef flats 

suggests that individual fish may be quite restricted 

in their food-gathering travels.

Study of stomach and gut contents of sedentary 

animals might throw additional light on the probable 

dwelling places of various species of Foraminifera, 

whether on algae of various kinds, or on coral, or in 

the sands or muds of the lagoon bottom.

Table 2 gives the species of Foraminifera found in 

the 22 samples of fish stomach and gut contents. In 

only three samples were species found in the fish that 

were not also found in the bottom sediments:

1. Clavulina multicamerata Chapman in fish No. 2. 

It differs from C. angularis d'Orbigny in a 

rounded cross section toward the apertural end 

instead of a triangular section throughout.

2. Triloculina terquemiana (Brady) in fish No. 3.

3. Eosalina rugosa d'Orbigny in fish No. 2. It differs 

from R. candeiana d'Orbigny in having very 

coarse perforations, which may prove to be not 

a specific distinction.

FORAMINIFERA FROM PITS

Samples were examined from seven pit sections well 

away from the beach. All the pits were shallow, three 

in the southern part and four in the central part of the 

northern main island. (See USGS Iocs, f 11639-f 11661 .) 

None of the four pits (GOC-4, GOC-5, GOC-6, and 

GOC-17) in the central part of the island exceeded 3 

feet in depth. The other three pits (GOC-1, GOC-2, 

and GOC-3) were deeper: about 6 feet, 9 feet, and 11 

feet, the deepest sample studied from the last hole, 

however, being at 10 feet.

Omitting the pit at GOC-17, all the excavations 

started in soil composed of nearly pure Calcarina sand, 

much darkened by organic matter, and in which roots 

were common. Some, but not all, of the specimens of 

Calcarina were much worn, presumably by abrasion 

before final deposition. The specimens also show the 

effects of corrosion by organic acids in the soil, in that 

many of the shells are porous with openings into the 

chamber cavities (pi. 25, fig. 7). The dark stain and 

porosity of the shells was not observed in material 

obtained from below a depth of about 1 foot.

The uppermost sections of the pits at GOC-1, 

GOC-2, and GOC-4 and the entire section of the pits
FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 185

at GOC-3, GOC-5, and GOC-6 are interpreted as 

beach sands. (See fig. 41.) These sands are composed 

of Calcarina with lesser amounts of Amphistegina, 

Marginopora, and Heterostegina. Minor elements, 

such as miliolids and species of Bolivina and CymbaJoporetta, increase with depth in pits GOC-3 and GOC-6. 

In the lower sections of these pits the orange color of 

the sand and good preservation of specimens is similar 

to that of modern beach sands, and there is only slight 

evidence of abrasion. Presumably the species in these 

pits lived not far from where they were deposited.

In pits GOC-1, GOC-2, and GOC-4 the beach sands 

are gradually transitional into sediments with a much 

smaller proportion of Calcarina and a greater variety 

of other Foraminifera. Nevertheless, even with the 

change, Calcarina remains the predominant element 

to the bottom of all the pits. (See pi. 25, figs. 8, 9.) 

These richer and more varied sediments are interpreted 

as a reef-flat horizon which was built up to become 

progressively shallower and finally to be overrun by 

the sediments of an adjacent beach sediments that 

now overlie it in the pits. The transition between 

beach sands and reef-flat sediment, however, occurs 

at different depths in the various pits. For example, 

the pit at GOC-3, although sampled to a greater depth 

than any other pit, did not even at a depth of 10 

feet reach the rich fauna of the reef flat horizon (fig. 41).

The pit at GOC-17 was dug through limesand and

limesilt throughout, and the entire 2-foot section is in 

sediments transitional between those of a reef-flat 

horizon and beach sands. No beach sands overlie the 

surface at GOC-17.

In addition to the pits on the northern main island, 

a small section is exposed above the beach on the 

lagoon side of the southern main island at GOC-20. 

Material in the 3%-foot section is beach sand (pi. 25, 

fig. 3), slightly richer and less well worn than that 

occurring in the area of the pits on the northern main 

island.

A few of the species found in the pits were not found 

in the lagoon sediments. None of them occur more 

than very rarely and all are known as Recent species:

Bdelloidina aggregata Carter 

Conicospirillina trochoidea Cushman 

Elphidium milletti (Heron-Alien and Earland) 

Neoconorbina frustata (Cushman) 

Patellina advena Cushman 

Pegidia dubia (d'Orbigny) 

Rosalina orientalis (Cushman) 

Spiroloculina corrugata Cushman and Todd

Among the species found rather consistently in the 

lagoon and reef sediments, the following are conspicuous 

by their absence from the pits:

Baculogypsina sphaerulata (Parker and Jones) 

Elphidium striato-punctatum (Fichtel and Moll) 

Hauerina involuta Cushman 

Spiroloculina clara Cushman 

Valvulina davidiana Chapman

GOC-1 GOC-2 GOC-3 GOC-4 GOC-5 GOC-6 GOC-17

f11639 

f11640 

(11641 

f11642

fl!643 

WATER LEVEL

fl!644

f 11645

f 11646

(11648

f11649

(11650 

(11651

(11654

(11655

f 11656 §3 f 11658

(11657

(11659

||||fll660

(11661

(11652

FEET 

1-5

EXPLANATION

(11653

(11639 

USGS locality

FIGURE 41. Diagrammatic sections of seven dug pits on the northern main island of Onotoa Atoll. For detailed illustrations of Foraminifera sands of GOO-ID see

pi. 25, fig. 9; of QOC-2F, pi. 25, fig. 8; QOC-6A, pi. 25, fig. 7.
186 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

For the last four species listed it is probable that a 

shallow reef-flat horizon is not the preferred habitat 

(see occurrence of these species in table 1), and hence 

their absence is not unexpected. For Baculogypsina 

sphaerulata, on the other hand, its absence in an 

environment known to be its preferred habitat is 

surprising and suggests the existence of some prohibitive factor, as discussed in the following section.

LOCAL DISTRIBUTION OF CALCARINA AND 

BACULOGYPSINA

With but two exceptions, the more abundant species 

at Onotoa seem to be distributed more or less uniformly, though in varying proportions depending upon 

the facies. The two exceptions are Calcarina spengleri 

(Gmelin) and Baculogypsina sphaerulata (Parker and 

Jones). Both of these two species are believed to be 

mainly reef dwellers although some live specimens 

were also found in the bottom sediments adjacent to 

reefs and in some beach sands (f 11676, GOC-38) and 

coarse shallow sediments (f 11677, GOC-45) of the 

lagoon.

Figure 40 shows the 27 localities where either one 

or both of these species was found to constitute a 

significant part of the Foraminifera population. Symbols indicate the approximate relative abundance of 

these species to each other (not to the total fauna). 

In table 1 it ^ill be observed that either or both are 

present in many other samples, but less abundantly.

It may be seen that in the overall picture Calcarina 

dominates. It is present to the exclusion of Baculogypsina in 11 of the localities. In only 3 localities is 

Baculogypsina present alone, while in the remaining 13 

localities the 2 genera are found together, though 

possibly not living together. Even though live specimens were found in the same sample, easy transport 

over short distances by means of surf or currents leaves 

the possibility open that the two genera do not occupy 

precisely the same ecological niche. In general the 

samples where Baculogypsina is predominant are from 

localities in or near breaks in the reef and away from 

land areas (pi. 25, figs. 1, 2).

I have no theories as to the reason for the separate 

geographic occurrence, here and elsewhere, of these 

two genera. I believe it is more than a chance distribution, and more than a result of incomplete collection of 

or examination of samples. In each of the seven pits 

(fl!639-f 11661, GOC-1 to GOC-17) only Calcarina 

was found. As two of these pits (GOC-2 and GOC-3) 

afford sections of about 9 and 10 feet, respectively, 

the sediments penetrated probably represent deposition over a considerable period of time. The fact that 

only Calcarina was found in all the pit samples suggests 

that Baculogypsina may have been a comparatively

late comer to this atoll. However Baculogypsina is 

not a late comer in the general area of the western 

Pacific as is evidenced by the fact that at Bikini and 

Eniwetok atolls it is found in the shallow drillings but 

is not present in the Recent fauna.

NOTES ON SELECTED SPECIES

Chrysalidinella dimorpha (Brady) 

Plate 22, figure 10

Chrysalidinella dimorpha (Brady). Cushjnan, 1945, Cushman 

Lab. Foram. Research Contr., v. 21, p. 52, pi. 8, figs. 

21, 22.

This species is characterized by its elongate and 

straight-sided form. Only a single specimen was found.

Elphidium cf. E. poeyanum (d'Orbigny) 

Plate 23, figure 1

Rare specimens found in several of the lagoon samples 

are distinctive in having a nearly transparent wall, 

uninflated test, and very short retral processes. In 

these characteristics they are similar to Elphidium 

poeyanum (d'Orbigny) (Cushman, 1939, p. 54, pi. 14, 

figs. 25, 26), a common species of the West Indian 

region. They are easily distinguishable from E. simplex 

Cushman, which has an umbilical plug, a milky wall, 

and a tendency toward inflation of the later chambers. 

I have not observed this very transparent species 

elsewhere in the western Pacific.

Globigerina cf. G. inflata d'Orbigny 

Plate 24, figure 1

Rare specimens in the lagoon samples, mostly in 

those samples from areas open to the ocean on the 

southwest, seem related to Globigerina inflata d'Orbigny 

(Cushman, 1946, p. 16, pi. 3, fig. 3; pi. 4, figs. 1-4). 

They are close coiled with four chambers making up 

the final whorl and have a large, arched and rimmed 

aperture that opens into the umbilicus.

Globigerina inflata was not found in the Globigerina 

oozes around the Marshall Islands, nor was it observed 

among the rare globigerinids found in the shallow sediments around Saipan. Its nearest reported occurrence 

seems to be the Mid-Pacific seamounts (Hamilton, 

1953, p. 222).

Globigerinita glutinata (Egger) 

Plate 24, figure 3

Globigerinita glulinata (Egger). Phleger, Parker, and Peirson, 

1953, Swedish Deep-Sea Exped. Repts., v. 7, Sediment 

cores from the North Atlantic Ocean, no. 1, p. 16, pi. 2, 

figs. 12-15.

Rare specimens of this small globigerinid occur in 

the lagoon and in the area open to the ocean. One
FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 187

occurrence was from sediments interpreted as a reefflat horizon from the bottom of one of the pits.

Neoconorbina terquemi (Rzehak)

Rosalina orbicularis Terquem, 1876, Essai Classement Animaux

Plage Environs Dunkerque, Paris, fasc. 2, p. 75, pi. 9,

fig. 4. 

Rosalina terquemi Rzehak, 1888, Austria Geol. Reichsanst.,

Verb., p. 228. 

Conorbina orbicularis (Terquem). Parker, 1954, Harvard

Coll. Mus. Comp. Zoology Bull., v. Ill, no. 10, p. 522,

pi. 8, figs. 13, 14.

This species is type of the genus Neoconorbina; the 

name terquemi was proposed to differentiate Terquem's 

species from one described earlier under the name by 

d'Orbigny.

The species occurs in a few of the lagoon and reef-flat 

samples, in some samples fairly commonly. Their low, 

flat, scalelike shape suggests they were attached in 

life.

Nubeculina divaricata (Brady)

Nubeculina divaricata (Brady). Cushman, 1932, U.S. Natl. 

Mus. Bull. 161, pt. 1, p. 48, pi. 11, figs. 5, 6.

This miliolid with arenaceous coating is generally 

recognizable only when its uncoated tubular neck is 

preserved. It was found in a few of the lagoon and reef 

samples.

Placopsilina bradyi Cushman and McCulloch

Placopsilina bradyi Cushman and McCulloch, 1939, Allan Hancock Pacific Exped., v. 6, no. 1, p. 112, pi. 12, figs. 14, 15.

Placopsilina cenomana Brady [not d'Orbigny] 1884 [part], 

Challenger Rept., Zoology, v. 9, p. 315, pi. 36, fig. 1 [not 

figs. 2?, 3].

Several specimens of this permanently attached form 

were found on the surfaces of shells and algae from the 

reef edge (f 11681, GOC-52). They consist of a series 

of coarsely agglutinated chambers, initially coiled, then 

in a uniserial arrangement and an irregularly winding 

course.

The first mention of this species (see second reference 

in synonymy) included two and possibly three types of 

forms under the name Placopsilina cenomana: figure 1, 

coarsely arenaceous, white, and with transverse measurements of 0.30-0.45 mm; figure 3, arenaceous, orange, 

and with transverse measurements of 0.04-0.08 mm; 

and figure 2 possibly differing in being either finely 

arenaceous or not agglutinated. The distinction between the very small orange one and the larger white 

one was recognized by the erection in 1920 of P. confusa 

Cushman (1920, p. 71, pi. 14, fig. 6) for the former, 

leaving the latter in P. cenomana d'Orbigny. The 

original description of P. bradyi, however, included all

three of Brady's figures in synonymy, probably by 

oversight, as no mention of P. confusa is made, and the 

description, figures, and a paratype in the U.S. National 

Museum collection (USNM 35815) all indicate that a 

form equivalent to Brady's figure 1 (not fig. 3) is meant 

to carry the name of P. bradyi.

As comparison of type material of the two species, 

P. confusa and P. bradyi, indicates possible if not 

probable specific differences between the two, the name 

P. bradyi is retained for the Onotoa specimens.

Placopsilina? sp.

Plate 22, figures 3, 4; plate 25, figure 5d

Rare fragments of irregularly curving cylindrical 

agglutinated tubes, consisting of uniserial chambers 

varying in height but usually quite low and uneven in 

shape, were found in three lagoon samples. One unbroken end shows a smooth, round, and unrimmed 

apertural opening in the depressed center of the final 

chamber. These fragments may be the upward-growing 

parts of attached specimens of Placopsilina.

Quinqueloculina polygona d'Orbigny 

Plate 22, figure 5

Quinqueloculina polygona d'Orbigny, 1839, in De la Sagra, 

Histoire physique, politique et naturelle de 1'lle de Cuba, 

Foraminiferes, p. 198, pi. 12, figs. 21-23. 

Cushman, 1932 [part], U.S. Natl. Mus. Bull. 161, pt. 1, 

p. 25, pi. 6, fig. 6 [not fig. 5].

Typical specimens of this angular miliolid that was 

described from shore sands of Cuba are present, sometimes abundantly, in the Onotoa samples.

Rectobolivina? sp. 

Plate 22, figure 8

RectoboUvina sp. Todd, 1957, U.S. Geol. Survey Prof. Paper 

280-H, p. 290-291 (table)

In the Onotoa material, particularly that from the 

reef-flat horizons in pits GOC-1 and GOC-2, are rare 

specimens that are questionably referred to this genus. 

They are identical with some from Tanapag lagoon, 

Saipan. They are always in association with Siphogenerina raphana (Parker and Jones) from which they 

are distinguishable by their much smaller size (0.35- 

0.55 mm long), slenderer form (0.10-0.20 mm wide), 

more translucent wall, proportionally longer multiserial 

stage (becoming biserial but twisted in the present 

material), and the slightly indented sutures and hence 

slightly lobulated outline. They may prove to be 

related to Siphogenerina raphana, possibly being included in the same species.
188 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Rosalina candeiana d'Orbigny

Rosalind candeiana d'Orbigny, 1839, in De la Sagra, Histoire 

physique, politique et naturelle de 1'Ile de Cuba, Foraminiferes, p. 97, pi. 4, figs. 2-4.

Discorbis opima Cushman, 1933, Cushman Lab. Foram. Research Contr., v. 9, p. 88, pi. 9, fig. 3.

This is the commonest of the discorbids found at 

Onotoa, occurring in nearly all the lagoon samples and 

on the reef flats. It is too fragile to persist in the beach 

sands. As is typical of the family Discorbidae, specimens were probably loosely attached by their ventral 

surfaces during life, but not cemented, so that as 

empty tests they were easily washed down into the 

bottom sediments.

Rosalina concinna (Brady)

Discorbina concinna Brady, 1884, Challenger Kept., Zoology, v 9, 

p. 646, pi. 90, figs. 7, 8.

Discorbis micens Cushman, 1933, Cushman Lab. Foram. Research Contr., v. 9, p. 89, pi. 9, fig. 5.

This small circular scalelike species was also attached 

during life. It is almost surely the early stage of the 

species of Tretomphalus that is called T. concinnus 

(Brady), referring to the same Brady reference as above. 

Thus the separation of these two forms is wholly 

artificial and a matter of convenience. In most samples 

where either is common, the two forms occur together.

Rosalina orientalis (Cushman)

Discorbis orientalis Cushman, 1926, B. P. Bishop Mus. Bull. 27,

p. 130 [imprint date 1925].

Todd, 1957, U.S. Geol. Survey Prof. Paper 280-H, p. 290- 

291 (table), pi. 90, fig. 13.

Comparison with the types indicates that this species 

is merely a high-spired form of Rosalina candeiana.

Spiroloculina rugosa Cushman and Todd

Spiroloculina rugosa Cushman and Todd, 1944, Cushman Lab. 

Foram. Research Spec. Pub. 11, p. 66, pi. 9, figs. 9-13.

A single specimen of this species with its distinctively 

rugose wall was observed in f 11667, GOC-29.

Spiroloculina venusta Cushman and Todd

Spiroloculina venusta Cushman and Todd, 1944, Cushman Lab. 

Foram. Research Spec. Pub. 11, p. 60, pi. 8, figs. 16, 17.

This species was found rarely in the lagoon samples. 

Svratkina sp.

Epistominella sp. D, Todd, 1957, U.S. Geol. Survey Prof. Paper

280-H, p. 292-293 (table), pi. 92, fig. 2. 

Svratkina sp. A, Todd and Low, 1960, U.S. Geol. Survey Prof.

Paper 260-X, p. 840.

The genus Svratkina was erected (Pokorny, 1956, p. 

257) for specimens that had been previously reported 

under various other names from Australia, Europe,

and America and from the Eocene (if not older) to the 

Recent. This compact and close-coiled genus is distinguished by large pores, particularly on the dorsal 

side, the pores sometimes surrounded by tubular necks, 

and by the aperture being a long, narrow opening extending from the umbilicus along the base of the 

apertural face to a depression beneath the periphery 

where it widens and extends upward into the apertural 

face.

The first reference cited above is to specimens of this 

genus from Recent lagoon sediments of Saipan; the 

second to specimens from the upper part of the Eniwetok drill holes in the Marshall Islands. Identical specimens are found rarely at Onotoa. They seem very 

close to the type of the genus, Discorbis tuberculata 

(Balkwill and Wright) var. australiensis Chapman, 

Parr, and Collins, but may prove to be distinct when 

sufficient material becomes available.

REFERENCES CITED

Cloud, P. E., Jr., 1952, Preliminary report on geology and marine 

environments of Onotoa Atoll, Gilbert Islands: Natl. Acad. 

ScL, Natl. Research Council, Pacific Sci. Board, Atoll Research Bull. 12, p. 1-73, figs. 1-8.

 1959, Geology of Saipan, Mariana Islands. Part 4,

Submarine topography and shoal-water ecology: U.S. Geol.

Survey Prof. Paper 280-K, p. 361-445, pis. 2, 120-139,

figs. 36-43. 

Cushman, J. A., 1920, The Foraminifera of the Atlantic Ocean.

Part 2, Lituolidae: U.S. Natl. Mus. Bull. 104, pt. 2, p. 1-

111, pis. 1-18.

 1939, A monograph of the foraminiferal family Nonionidae: U.S. Geol. Survey Prof. Paper 191, p. 1-100, pis. 

1-20.

1946, The species of Globigerina described between 1839

and 1850: Cushman Lab. Foram. Research Contr., v. 22, 

p. 15-21, pis. 3, 4.

Cushman, J. A., Todd, Ruth, and Post, R. J., 1954, Recent 

Foraminifera of the Marshall Islands: U.S. Geol. Survey 

Prof. Paper 260-H, p. 319-384, pis. 82-93, figs 116-118.

Hamilton, E. L., 1953, Upper Cretaceous, Tertiary, and Recent 

planktonic Foraminifera from Mid-Pacific flat-topped seamounts: Jour. Paleontology, v. 27, p. 204-237, pis. 29-32, 

figs. 1-5.

Myers, E. H., 1943, Biology, ecology, and morphogenesis of a 

pelagic foraminifer: Stanford Univ. Pubs., Biol. Sci., v. 9, 

no. 1, p. 1-30, pis. 1-4.

Pokorny, Vladimir, 1956, New Discorbidae (Foraminifera) from 

the upper Eocene brown Pouzdfany marl, Czechoslovakia: 

Prague, Univ. Carolina, Geologica, v. 2, no. 3, p. 257-278, 

figs. 1-15.

Todd, Ruth, 1957, Smaller Foraminifera, in Geology of Saipan, 

Mariana Islands. Part 3, Paleontology: U.S. Geol. Survey 

Prof. Paper 280-H, p. 265-320, pis. 2, 4, 64-93, tables 1-4.

Todd, Ruth, and Low, Doris, 1960, Smaller Foraminifera from 

Eniwetok drill holes: U.S. Geol. Survey Prof. Paper 260-X, 

p. 799-861, pis. 255-264, text figs. 256-259, tables 1-7.

Walton, W. R., 1952, Techniques for recognition of living Foraminifera: Cushman Found. Foram. Research Contr., v. 3, 

pt. 2, p. 56-60.
INDEX

A Page

Abanekeneke..____________-__ 176 

Acanthurus gahhm.......--................_ 182,183

acervalis, Planorbulina.....______ 176,180,183

Acervulina.................................. 182,184

inhaerens-................. ____ 176,180,183

sp ..._ 180

acicularis, Spirolina__- ....__.__.... 178

Acknowledgments.___...______.__ 171 

aculeatus, Rhinecanthus___________ 182,183 

advena altiformis, Patellina.................... 179

Patellina--- ........................ 179,185

advenum dispar, Elphidium............. 176,179,183

Elphidium......__._-...________ 179

aequilateralis, Olobigerinella.......... _____ 180

apglutinans, Quinqueloculina.................. 177

Textularia................................ 177

aggregata, Bdelloidina....................... 178,185

Aiaki Maneaba... . 174,175,176; pi. 25 

AUiatina translucens.--.....-............ 179; pi. 23

altiformis, Patellina advena-................... 179

alveola, Textularia-------------..... ...___ 177

Alveollnellidae.---------------------------_ 178

alveoliniformis, Ammomassilina-. .......__ 178

Schlumbcrgerina............ 176,178,181,182,183

A mmobaculitessp ------................ 177; pi. 22

A mmomassilina alveoliniformis_________ 178 

ammonoides, Operculina ..................... 181

Amphistegina ...................... 182,185; pi. 25

madayascoriensis.---. 176,179,181,182,183; pi. 25 

Amphisteginidae-______-_______ 179,183 

anguina arenata, Quinqueloculina............. 177

angularis, Clavulina----................. 177,183,184

angulata, Spiroloculina---............... 176,177,183

Anomalina glabrata........................... 180

Anomalintlla rostrata......................... 181

Anomalinldae------___.............. 180,182,183

Aon teBaba.. --- -. 174,175; pi. 25 

Aontebeke land area.-._______.___. 176

Aon te Rabata shoals... .-.______- 174,175 

arenata, Quinqueloculina anguina............. 177

arietini, Spirolina--_________ 176,178,181,183 

Arothron nigropunctatus....... ____..._ 182,183

Articulina elongata.-.......................... 178

pacifica____________________ 178 

auriculata, Wiesnerella........................ 178

australiensis, Discorbis tuberculata............. 188

australis, Miliolinella................... __ 178,183

B

Baculogypsina........... 172,174,175,184,186; pi. 25

sphaerulata...... 176,179,181,183,185,186; pi. 25

Balistapus undulatus....................... 182,183

Bdtlloidina aggregata-....................... 178,185

Beach sands. ...... .. 171,176,185,186; pi. 25

beccarii, Streblus.................... 179,181,182,183

tepida, Streblus............ ________ 179

berthelotiana, Quinqueloculina--.....____ 177

bicarinata, Triloculina----..................... 177

bidentata, Quinqueloculina---_____ 177,183; pi. 22 

Bikini atoll, Marshall Islands----.-....__ 181,186

Bolivina.................................... 182,185

compacta............................_.... 179

(Loxostomum) limbota....._.............. 179

mayori---............................. 179

rhomboidalis.. ________________ 179 

striatula................................ 179,183

subexcavata............................... 179

tortuosa.-................................. 179

Bolivintlla folium........................... 178,181

Borelis pulchrus..___.________ 178

[Italic numbers indicate descriptions]

Page 

bradyi, Cymbaloporetta.......... 176,179,181,182,183

Parrina .________________ 178,183 

Placopsilina............................ 178,187

Buariki Maneaba--_____._____-.... 174

Ruliminella milletti........................... 178

Buliminidae.------..-----.---...-.-...-.-. 178,183

JRuliminoides williamsonianus........-.-.-.. 178,182

bulloides, Globigerina__....___.--__-. 180

buniva, Melichthys. -.......________ 182,183

C

Calcarina............ 172,173,174,184,185,186; pi. 25

hispida.-................................. 181

spengleri............. 176,179,181,183,186; pi. 25

Calcarlnidae. -- - -. 179,183

Camerinidae---. ........................ 178,183

candeiana, Rosalina............. 176,179,183,184, 188

Textularia.............................. 177,183

Cantherines sandwichensis...........-------- 182,183

Cardium---................................... 174

Cassidulina minuta......................... 179,182

Cassidulinidae -- 179

cenomana, Placopsilina....................... 187

Chrysalidinella dimorpha............. 179, 186; pi. 22

Cibicidella... .................... . 184

variabilis - .................. 176,180,183

Cibicides -- -- 184

cicatricosus..-................ 180

lobatulus... . - 180,183

mayori-.-......................----------- 180

pseudoungerianus---------....------------ 180

cicotric"sus, Cibicides.........................- 180

clara lirata, Spiroloculina---................ - 177

Spiroloculina................... IT!, 182,183,185

Clavulina angularis..................... 177,183,184

multicamerata......._____.- 183,184

communis, Spiroloculina..............- 177

compacta, Bolivina.....................------- 179

concinna, Discarbina.......................... 188

Rosalind 179,183,188

concinnus, Tretomphalus..... 176,179,183,188; pi. 24

confusa, Placopsilina-_____----- - 187

conglobatus, Globiqerinoides-................... 180

Conicospirillina trochoidea-.......... 179,185

sp.--- 179,183; pi. 23

Conorbina orbicularis-.-....................... 187

Corvuspira planorbis--.................. 176,178,183

corrugata, Spiroloculina..................... 177,185

cribrorepandus, Poroeponides............ 179,182,183

crispum, Elphidium..................... 176,179,183

Ctenochaetus cyanoguttatus.................. 182,183

gtriatus. 182,183

cuneata, Triloculina-..................... 177,183

cyanoguttotus, Ctenochaetus.......... 182,183

Cymbaloporetta..................... .. 184,185

bradyi...................... 176,179,181,182,183

squammosa................. 176,179,181,182,183

Cymbaloporidae.--.... _ .... 179,182,183

D 

dovidiana, Valvulina.................... 177,182,185

decorata, Spirillina-........................... 179

denticulata, Pyrgo.-_____.__------ . 178

denticulo-granulata, Spirillina.....-- - 179; pi. 23

dimorpha, Chrysalidinetta.......... 179, 186; pi. 22

Discorbidae---.------------------------ 179,183,188

Discorbina concinna.-......................... 188

Discorbis micens..........____---- -- 188

opima.................................... 188

orientolis - 188

tuberculata australien sis................... 188

Page 

dispar, Elphidium advenum........._... 176,179,183

distcrqueata, Quinqueloculina ................ 177

Distribution of Calcarina and Baculogypsina, 

local ------.----.-_.....__-._.__., 186

Distribution of Recent Foraminifera.___ 177-180 

divaricata, Nubeculina....................... 178,187

diversa, Hauerina... . ............. 178

dubia, Pegidia.............................. 179,185

dupla, Textularia........................... 177,182

E

earlandi, Triloculina-______________ 177 

echinatus, Siphoninoides-.................... 179,182

eggeri, Olobigerina-......... .... 180;pl.24

ellipticus, Peneroplis___________ 178,182,183 

elongata, Articulina-....-.-.-....... 178

Elphidiidae-.. . - - 179,183

Elphidium.................................... 182

odvenum.................................. 179

dispar.......................... 176,179,183

crispum.. ____ 176,179,183

miaetti 179,185

poeyanum............ .... 179,186;pl.23

simplex............. ...-...-..... 179,183,186

striato-punctatum......................... 176,

179,181, 182,183,185; pi. 25

Eniwetok atoll, Marshall Islands.- 181,186,188 

Epistomaroides polystomelloides...-.......... 179, 182

Epistominella tubulifera ---- 179,182

sp.. 188

Examination offish contents....... 182-184

exigua, Planispirinella........................ 178

eximia, Spiroloculina-......................... 177

F

Fauna 176-181

ferussaci, Quinqueloculina........... 177

Fischerina pellucida.... 178; pi. 22

Fischerinidae.-___ 178

Fissurina lacunata. 178

lagenoides___.__ -- 178

milletti-... 178

foliacea oceanica, Textularia.......... 177,181,182

Textularid 177,181,182

folium, Bolivinella.............. - 178,181

frondescens, Sagenina......................... 177

frustata, Neoconorbina..--..........------ - 179,185

G

gahhm, Acanthurus.. 182,183 

Oaudryina pauperata.-. - 177,183

(Siphogaudryina)..........--. .. 182

rugulosa-..-. - 176,177; pi. 25

siphonifera.... .. - 177

glabrata, Anomalina............-------....... 180

Globigerina bulloides...........-.-------------- 180

eggeri................... . 180; pi. 24

inflate . 180, 186; pi. 24

Glcbigerinella aequilateralis-------------------- 180

Globig' rinida»-._......... 180,183

Globigerinita glutinata. 180, 186; pi. 24

Globigerinoides conglobatus............-------- 180

ruber- 180,183

sacculifer............ 180,183

globula, Oypsina........---- - - I80

glutinata, Globigerinita.- - 180, 186; pi. 24 

Government Station... 173,174,175,176; pi. 25 

Gypsina globula-- .....--- ---- ----------- 1^

plana.................- - --- I80

... 180 vesicularis.

189
190 INDEX

H Page 

Haddonia torresiensis.................... 176,178,182

Halimeda..................................... 174

Hauerina diversa..... ____ __ _____ _. 178

involuta .......................... 178,183,185

milletti- .............................. 178,183

pacified.......-.....------- __-_-. 178,183

serrata_________________ 178

speciosa ................................ 178

Heliopora .............................. 173,174

Heterohelicidae..________________ 178 

Heterostegina------................... 184,185; pi. 25

suborbicularis--.......n6, 178,181,183,184; pi. 25

hispida, Calcarina............................. 181

Homotrema ......... ................... 182,184

rubrum......................... 176,180,182,183

Homotremidae.________________ 180,183 

Hyperamminidae--______________ 177

I

inaeaualis, Spirillina-__________ __. 179 

incisura, Triloculina........................ 177,183

inflata, Globigerina-.................. 180, 186; pi. 24

inhaerens, Acervulina__________ 176,180,183 

Introduction___.- . ...____ 171 

involuta, Hauerina...................... 178,183,185

irregularis, Triloculina................. 176,177,183

Islands along east side________ 171,176,177-180

K

kerimbatica, Triloculina.........._____ 177,183

L 

labiosa, Miliolinella....................... .. 178,183

lacunata, Fissurina...___________ 178

lagenoides, Fissurina.....------............... 178

Lagoon._............. 171,176,177-180,181,182,184

Leeward side---.------...--------- 171,176,177-180

limbata, Bolivina (Loxostomum)............... 179

lirata, Spiroloculina clara. .................. 177

Lituolidae ...... ... ............... 177

lobata, Forties_____________..__ 174

lobatulus, Cibiddes.......................... 180,183

Locality data_________________ 173-176 

(Loxostomum) limbata, Bolivina............... 179

mayori, Bolh'ino.......................... 179

M

madagascariensis, Amphistegina............... 176,

179,181,182,183; pi. 25

Mangaia land area____._---_____-. 176 

marginalis, Sorites.......................... 178,182

Marginopora . . 173,174,175,184,185; pi. 25 

vertebralis ................ 176,178,181,183,184

Mariana Islands_______----____ 181

Marshall Islands.--__............... 181,186,188

marshallana, Triloculina...................... 177

Massilina planata............................ 177

Material studied..._______________ 171 

mayori, Bolivina (Loxostomum).............. 179

Cibiddes.................................. 180

Melichthys buniva........................... 182,183

micens, Discorbis- ......._________ 188

Mid-Paciflc seamounts..____________ 186 

Miliolidae .................. 177,178,183

Miliolivella australis........................ 178,183

labiosa.................................. 178,183

oceanica.........................___.. 178

milletti, Buliminella________..____ 178 

Elphidium.............................. 179,185

Fissurina--............................... 178

Hauerina............................... 178,183

minuta, Cassidulina.-..-................... 179,182

Monalysidium politum_....................... 178

multicamerata, Clavvlina--.................. 183,184

N

Nanntabuariki islet..._________ 174; pi. 25 

N"eoconorbina......... _________.. 182,184,187

frustata................................. 179,185

patflliformis........................ 176,179,183

terguemi................................ 179, 187

tuberocapitata_________.___. 179

Page 

neostriatula, Quinqueloculina-............... 177,183

nigropunctatus,Arothron. ................ 182

Nonion pacificum............................. 179

Nonionella sp___________________ 179 

Nonionidae -__________________ 179 

Notes on selected species-.-..-______-. 186-188 

Nubeculmadivaricata....................... 178,757

O

obliguiloculata, Pulleniatina...---------.180; pi. 24

oblonsa, Triloculina .................. 176,177,183

octanica, Miliolinella ---.-................... 178

Textulariafoliacea- ............... 177,181,182

Operculina ammonoides-...................... 181

Ophthalmidlidae-.-........................ 178,183

opima, Discorbis.............................. 188

orbicularis, Conorbina....... _______-__ 187

Rosalina--................................ 187

Orbulinauniversa........................ 180; pi. 24

orientalis, Discorbis........................... 188

Rosalina............................ 179,185, 188

Otoae village Maneaba_...__---_- 174; pi. 25

Pacific Science Board campsite____ 173; pi. 25

pacifica, Articulina--...___-_____-- 178

Hauerina............................... 178,183

pacificum, Nonion........................... 179

popifata, Sphatridia.-........................ 179

Parrina bradyi.............................. 178,183

patelliformis, Neocmorbina......... .. 176,179,183

Patellino advene............................ 179,185

advena attiformis.................__.--- 179

pauperota, Gaudryina....................... 177,183

Pegidiadubia............................... 179,185

Pegidiidae ........................ .. 179

ptllucida, Fischerina.................. 178, pi. 22

Peneroplidae. - 178,183

Peneroplis ellipticus.................... 178,182,183

proteus.......................... 178,183; pi. 22

Pitts, Foraminifera from ________ 171,

176, 177-180, 184-186; pi. 25

Placopsilina.................................. 187

bradyi.................................. 178,187

cenomcna________________ .. 187 

confuso......__________--.- . 187

sp . 178, 182, 187, pis. 24 25

Placopsilinidae_________________ 178 

plona, Gypsina............................... 180

planota, Massilina--................--.. 177

Plonispirinella exigua..........-.............. 178

planorbis, Cornuspira................... 176,178,183

Planorbulina............................... 182,184

acervalis-.. ...................... 176,180,183

rubra-.......................... 180

Planorbullnldae... 180,182,183

Planorbulin aides..............---------------- 184

retinaculatus - ................ 180,182,183

planus, Tretomphalus-.......... 176,179,183; pi. 24

poeyanum, Elphidium-.............. 179,186; pi. 23

politum, Monalysidium. ___------ - 178

polygona, Quingueloculina ... 176,177,187; pi. 22 

Polymorphinidae..__--.-_--- ---- 178

polystomellcides, Epistomaroides............. 179,182

Porites lobata................. --.-- - 174

Poroeponides cribrorepandus.- .... .... - 179,182,183

porrtcta, Uvigerina___-__ - 179 

proteus, Pentroplis................... 178,183; pi. 22

pseudoungerianus, Cibiddes................... 180

pulchrus, Borelis--........ ........... 178

Pullenfttinaobliquiloculata ............ 180; pi. 24

Pyrgo dentkulata... _____ 178 

Pyropilus rotundatus 176,179,182; pi. 22

Quinqueloculina agglutinans_ - --- 177 

anguina arenata. __----- ------ 177

berthelotiana___ 177

bidentata-... ........-. - 177,183; pi. 22

Quinqueloculina Continued Page 

distorgueata ... ............................ 177

ferussaci. ... .............................. 177

neostriatula-....-.-..... ................ 177, 183

polygona.... ... . ..... . ..... 176, 177, 187; pi. 22

sulcata... ....... . ... ....... ..... ..... ... 177, 183

tubus ..... ...... .... -...-.. ..-. 177

R

Rakai Ati reef. - 175 

Maneku. __ 175 

ni Make 175

raphana, Siphogenerina..... .... . ... 176,179,183,187

Rawa ni Karoro -- 174 

rectangulus, Rhinecanthus- ............. . .... 182,183

Rectobolivina sp~. 179, 183, 187; pi. 22

Reef areas 171, 176, 177-180, 181, 184, 185 

References cited 188 

retinaculatus, Planorbulinoides. ......... 180,182,183

Reussella simpl'x.... ... ............ 176, 179, 182, 183

revertens, Spirillina vivipara ................... 179

Rhinecanthus aculeatus. _ .- ___ .- 182, 183 

rectangulus........ ....... ........... ... 182,183

rhomboidalis, Bolivina-- ...... .......... ...... 179

Robertinidae -- - - - 179 

Rongelap atoll, Marshall Islands- -. 181 

Rongerik atoll, Marshall Islands ---------- 181

Rosalina 182, 184

candeiana 176, 179, 183, 184, 188

condnna . - - 179, 183, 188

orbicularis...- .......... ... ...... . ....... 187

orientalis . . 179, 185, 188

rugosa 183, 184

-------------------------------- 187

rostrata, Anomalinella- - 181 

Rotaliidae 179, 183

rotundatus, Pyropilus .......... 176, 179, 182; pi. 22

ruber, Globigerinoides ... .................. 180,183

rubra, Planorbulina. ....... 180

rubrum, Homotrema...... .......... 176, 180, 182, 183

rugosa, Rosalina- ...... - ---- 183,184

Spiroloculina-.---. . 177,188

rugulosa, Gaudryina (Siphogaudryina). 176, 177; pi. 25

sacculifer, Globigerinoides.. ----- 180,183

Sagenina frondescens............... ... - 177

Saipan Island-... 181,186,187,188

sandwichensis, Cantherines.................. 182,183

Scan/a sp__-- 182,183 

ScHumbergerina alveoliniformis- 176,178,181,182,183 

serrata, Hauerina........ ... ---------- 178

Sigmomorphina terguemiana 178 

simplex, Elphidium..... .- 179,183,186

Reussella--- - -- 176,179,182,183 

(Siphogaudryina), Gaudryina.................. 182

rugvlosa, Gaudryina..............176,177; pi.25

siphonifera, Gaudryina......... ....... 177

Siphogenerina raphana. .. 176,179,183,187 

siphonifera, Gaudryina (Siphogaudryina)-... 177 

Siphonina tubulosa 179

Sipl-oninoides echinatus................. . 179,182

Sorites marginalis...............- ----- 178,182

Southern part of atoll 171,177-180

speciosa, Hauerina............---------------- 178

spenf/leri, Calcarina.- 176,179,181,183,186; pi. 25 

Sphaeridia papillata.- . ---------------- 179

sphaerulata, Baculogypsina 176, 179, 181, 183, 185,

186; pi. 25 

spinata, Triloculina- 177

Spirillina.------------ ..- 182

decorata- .. . - -- 179

denticulo-granulata........ -..-- 179, pi. 23

inaeaualis.-.-......... 179

tuberculato-limbata............-... ..- 179

vivipara.. - 179,183

revertens--- 179

SpiriUinidae 179,183

Spirolina adcularis..-.. -.. - 178

arietina ........ 176,178,181,183
INDEX 191

Page

Spiroloculina angulata. . _. ________ 176.177,183 

cZara__ ---_--- --- ----- 177,182,183,185

lirata...... - ----- 177

communis...... .-__--- --------------- 177

corrugata.-.-.....___--- --_----- 177,185

ezimia........ --- -- ------ 177

rugosa.......-___---____-.-_-__ 177, 188

venusta.-...---------------------------- 177, 188

sguammosa, Cymbaloporetta..... 176.179,181,182,183

Streblus beccarii._____._____ 179,181,182,183 

beccarii tepida... ....................... 179

striato-punctatum, Elphidium.... 176, 179, 181, 182,

183,185, pi. 25 

striatula, Bolivina........................... 179,183

striatus, Ctenochaetus.........-_._____ 182,183

subexcavata, Boliiiina.......................... 179

suborbicularis, Heterostegina.... 176,178,181,183, 184;

pi. 25 

subplanciana, Triloculina......._____ 177,183

sulcata, Quinqueloculina.-----.............. 177,183

Svratkinasp............................ 179,183,^55

T 

Tabuarorae islet------__-____-__ 176; pi. 25

Maneaba.__________________ 175,176 

Taneang-Tekawa Maneaba-----__.__ 174, pi. 25

Tebaki 175, 176

Tekawa-.-.-----.---------------------------. 175

church-.. __- -- _-_ 174,175;pi. 25 

tepida, Streblus beccarii........................ 179

Te Rawa ni Bao . 175

Te Rawa Tekatoblbi.----... ____ _ 175

Page 

terquemi, Neoconorbina.....-------._-.-.---_ 179, 187

Rosalina..._________-____..__ 187 

terguemiana, Sigmomorphina.................. 178

Triloculina............................. 183,184

Textularia agglutmans......................... 177

alveata.................................... 177

candeiana............................... 177,183

dupla. ............................ 177,182

foliacea............................. 177,181,182

oceanica......................... IT!, 181,182

Textulariidae - - - ---. 177,183 

Thalassla..................................... 175

torresie nsis, Haddonia................... 176,178,182

tortuosa, Bolivina..............--------___ 179

transitions, Alliatina..................... 179;pi. 23

transversestriata, Triloculina................... 177

Tretomphalus............................ 182,184,188

concinnus................ 176,179,183,188; pi. 24

planus....................... 176,179,183; pi. 24

tricarinata, Triloculina........................ 177

trigonula, Triloculina....................... 177,183

Triloculina bicarinata...-.....-............... 177

cuneata................................. 177,183

earlandi.....-_.-__-___________-- 177

incisura................................. 177,183

irregularis........................... 176,177,183

kerimbatica................._____-. 177,183

marshallana............................... 177

oblonga............................. 176,177,183

spinata...--.-............................ 177

subplanciana............................ 177,183

Triloculina Continued Page 

terguemiana............................. 183,184

transversestriata...______________ 177 

tricarinata...........___________. 177

trigonula................................ 177,183

trochiidea, Conicospirillina.................. 179,185

tuberculata australiensis, Discorbis............. 188

tuberculato-limbata, Spirillina................. 179

tuberocapitata, Neoconorbina.......______ 179

tubulifera, Epistominella.................... 179,182

tubulosa, Siphmina........................... 179

tubus, Quinqueloculina___...._______ 177

U 

undulatus, Balistapus....................... 182,183

unirersa, Orbulina........................ 180; pi. 24

Uvigerinaporrecta....... ___--. 179

V 

Valvulina davidiana..................... 177,182,185

Valvulinidae-... ........................ 177,183

variabilis, Cibicidella..................... 176,180,183

venusta, Spiroloculina....................... 177,188

Verneuilinidae- - .-_-_..__-.-_ 177,183 

vertebralis, Marginopora......... 176,178,181,183,184

vesicularis, Gypsina.......________-- 180

visipara revertens, Spirillina................... 179

Spirillina............................... 179,183

W 

Wet samples----------_---------------- 181-182

Wiesnerella auriculata..................___ 178

williamsonianus, Buliminoides............... 178,182

Windward side 171

U. S. GOVERNMENT PRINTING OFFICE : 1961 O -553580
PLATES 22-25
PLATE 22

FIGURE 1. Ammobaculites sp. (p. 177 tab.)

USNM 626873, X 56; USGS fl!667, GOC-29. 

2. Quinqueloculina bidentata d'Orbigny. (p. 177 tab.)

USNM 626883, X 44; USGS fl!679, GOC-49; a, side view; b, apertural view. 

3, 4. Placopsilinat sp. (p. 187)

3. USNM 626879, X 27; USGS fl!678, GOC-48; a, b, opposite sides; 6, attached surface; c, edge view showing terminal 

aperture.

4. USNM 626880, X 27; USGS fl!678, GOC-48. Fragment of a terminal part that grew outward from initial 

attached portion.

5. Quinqueloculina polygona d'Orbigny. (p. 187)

USNM 626888, X 44; USGS f 11683, GOC-55; o, side view; b, apertural view.

6. Fischerina pellucida Millett. (p. 178 tab.)

USNM 626874, X 40; USGS fl!667, GOC-29.

7. Peneroplis proteus d'Orbigny. (p. 178 tab.)

USNM 626875, X 93; USGS f 11667, GOC-29.

8. Redobolivinal sp. (p. 187)

USNM 626872, X 140; USGS fl!649, GOC-2F; o, side view; b, top view.

9. Pyropilus rotundatus Cushman. (p. 179 tab.)

USNM 626889, X 56; USGS fl!684, GOC-56; o, dorsal view; b, ventral view; c, peripheral view. 

10. Chrysalidinella dimorpha (Brady). (p. 186)

USNM 626890, X 88; USGS fl!690, 51-S-6; o, side view; b, top view.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 354 PLATE 22

RECENT BENTHONIC FORAMINIFERA FROM ONOTOA ATOLL
PLATE 23

[a, Dorsal view; 6, ventral view; c, peripheral view, except as indicated]

FIGUBE 1. Elphidium cf. E. poeyanum (d'Orbigny). (p. 186)

USNM 626876, X 93; TJSGS fl!667, GOC-29; a, side view; b, peripheral view. 

2. AUiatina translucens (Cushman.) (p. 179 tab.)

USNM 626886, X 140; USGS f 11679, GOC-49; a, side view; b, peripheral view. 

3, 4. Conicospirillina sp. (p. 179 tab.)

3. USNM 626871, X 180; USGS fl!667, GOC-29.

4. USNM 626870, X 220; USGS f 11667, GOC-29. 

5. Spirillina denticulo-granulata Chapman, (p. 179 tab.) 

USNM 626881, X 93; USGS fl!679, GOC-49.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 354 PLATE 23

RECENT BENTHONIC FORAMINIFERA FROM ONOTOA ATOLL
PLATE 24

[a, Dorsal view; 6, ventral view; c, peripheral view]

FIGURE 1. Globigerina cf. G. inflata d'Orbigny. (p. 186)

USNM 626887, X 93; USGS £11679, GOC-49.

2. Orbulina universa d'Orbigny? (p. 180 tab.)

USNM 626891, X 112; USGS £11691, 51-S-7.

3. Globigerinita giutinata (Egger). (p. 186)

USNM 626877, X 194; USGS £11667, GOC-29.

4. Tretomphalus concinnus (Brady). (p. 179 tab.)

USNM 626885, X 93; USGS £11679, GOC-49. Side view.

5. Globigerina eggeri Rhumbler. (p. 180 tab.)

USNM 626878, X 112; USGS f 11670, GOC-33.

6. Tretomphalus planus Cushman. (p. 179 tab.)

USNM 626884, X 70; USGS fl!679, GOC-49. Side view.

7. Pulleniatina obliquiloculata (Parker and Jones), (p. 180 tab.) 

USNM 626882, X 70; USGS fl!679, GOC-49.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 354 PLATE 24

RECENT PLANKTONIC FORAMINIFERA FROM ONOTOA ATOLL
PLATE 25

[All figures X 15]

FIGURE 1. Baculogypsina sand from islet of Nanntabuariki on windward (northeast) side of Onotoa Atoll. USGS f 11662, GOC-19. 

Fresh specimens washed onto beach from adjacent reef flat.

2. Baculogypsina sand from southeast end of Tabuarorae islet, south end of Onotoa Atoll. USGS f 11687, 51-L-8. Wellworn specimens associated with Amphistegina and Calcarina.

3. Calcarina-bearing limesand from upper part of section above lagoon beach just south of Otoae village Maneaba, southern 

main island of Onotoa Atoll. USGS f 11663, GOC-20A. Specimens mostly well preserved.

4. Amphistegina-bearing limesand from lagoon floor in northern part of lagoon, about 4,600 ft S. 65° W. from lagoon end of 

Government Station jetty, Onotoa Atoll. USGS fl!695, 51-S-ll. From bottom of reentrant or depression in large 

lagoon reef patch.

5. Miscellaneous Foraminifera from limesand bottom at 14 ft in outer part of lagoon of Onotoa Atoll, slightly less than 4 

miles N. 85° W. from Aiaki Maneaba. USGS fl!666, GOC-28. Among others, Heterostegina suborbicularis d'Orbigny 

(a), Gaudryina (Siphogaudryina) rugulosa Cushman (6), Elphidium striato-punctatum (Fichtel and Moll) (c), Placopsilina? sp. (d), and Amphistegina madgascariensis d'Orbigny (e) are recognizable.

6. Amphistegina-bearmg limesand from seaward edge of Aon te Baba reef, west side of north end of Onotoa Atoll, about 

7,100 ft S. 50° W. from Tekawa church. USGS fl!670, GOC-33. Worn Amphistegina with associated Heterostegina 

and Marginopora.

7. Worn Calcarina beach sand, stained dark from organic matter and corroded by organic acids. From top 6 in. in pit 

GOC-6, north-central part of northern main island, about 2,400 ft north-northeast from Taneang-Tekawa Maneaba. 

USGS H1657, GOC-6A.

8. CaJcarina-bearing sand interpreted as reef-flat horizon from bottom of 9-ft pit GOC-2, southern part of northern main 

island, about 940 ft S. 25° E. from east (inshore) end of lagoon-side jetty at Government Station and 660 ft inshore 

from sea beach along line bearing S. 87° W. at Pacific Science Board campsite. USGS fl!649, GOC-2F.

9. Calcarina sand, interpreted as transitional between beach and reef flat, from near bottom of 6-ft pit GOC-I, southern 

part of northern main island, about 1,100 ft S. 41° E. from east (inshore) end of lagoon-side jetty at Government 

Station and 325 ft inshore from sea beach along line bearing S. 87° W. at Pacific Science Board campsite. USGS f 11642, 

GOC-1D. Both fresh (with spines) and worn specimens.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 354 PLATE 25

7 ^»*= V tfM»f ^ 8

FORAMINIFERA SANDS FROM ONOTOA ATOLL