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 Page Abstract______171 Examination of fish contents.______182 Introduction.______171 Foraminifera from pits.______----__ 184 Material studied______171 Local distribution of Calcarina and Baculogypsina ______186 Locality data_.______173 Notes on selected species.- ______186 Fauna______176 References cited-______188 Wet samples______181 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 coral reefs on the southwest side (fig. 40). Its dimen­ The distribution of 168 species and varieties of smaller Fo- sions are roughly 12 miles long and 4 to 5 miles wide. raminifera is recorded within the lagoon and on the reefs and Latitude and longitude at its northwestern end are beaches of Onotoa Atoll as represented by 33 surface samples and 23 pit samples. Nearly all the species are well known in 1°46' S. and 175°30' E. Its physical description may shallow-water sediments of the tropical Pacific; 7 are indetermi­ be found in a preliminary report by Preston E. Cloud, nate; none are described as new. The lagoon collecting localities Jr. (1952), who in 1951 made the collections upon were all but one from depths no greater than 20 feet, and mostly which this study is based. from areas protected from the open ocean. Preservation in Acknowledgments. I am indebted to Preston E. 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 Cloud, Jr., for making available the well-documented determination of the living places of certain of the species. material and to John E. Randall for the identifications Recognition of two major distinctive habitats- (a) reef sur­ of the fishes studied. For helpful suggestions and dis­ faces and their adjacent slopes and (b) limesand bottom of the cussions I am grateful to Preston E. Cloud, Jr., and to lagoon is based in part on the relative abundance of species Richard Cifelli. Invaluable help in preparation of and in part on the presence of live (stained) specimens. Four species Calcarina spengleri, Baculogypsina sphaerulata, material and tabulation of results was received from Amphistegina madagascariensis, and Marginopora vertebralis Doris Low. The illustrations of the individual speci­ make up quantitatively most of the foraminiferal material in mens of Foraminifera were made by Elinor Stromberg. the reef sediments. Major foraminiferal constituents of the lagoon sediments are, in quantitative order: Amphistegina MATERIAL STUDIED madagascariensis, Heterostegina suborbicularis, Marginopora vertebralis, and Elphidium striato-punctatum. Quantitatively Samples were studied from the following areas of insignificant because of their smaller size, but common or abun­ Onotoa Atoll: dant in most samples, are many species of miliolids and several (1) Area open to ocean on west (leeward) side of atoll species in each of the following families: Textulariidae, Penero- plidae, Buliminidae, Discorbidae, Cyinbaloporidae, Anomalini- (7 samples from depths between 3 and 18 feet); dae, and Planorbulinidae. Globigerinids are present, but only (2) Lagoon: rarely, and appear to have come in from the open ocean through (a) Southern part (8 samples from depths be­ breaks in the reef. Seventeen other families are represented tween 6 and 17 feet, with 1 exception, mostly by rare or scattered occurrences. f 11683 [GOC-55] collected from 48 feet) Stomach and gut contents of 22 fish were found to contain Foraminifera tests nearly as varied as the naturally occurring (b) Central and northern part (7 samples from fauna. The fact that most of the individual fish did not contain depths down to 20 feet); as great a variety as the composite of all the fish suggests a (3) Reef areas (3 samples from leeward side of atoll rather localized feeding area for each fish. and 2 from windward); Seven pits provide short sections a maximum of 10 feet into (4) Southern part of atoll (4 samples of fine sediment the sediments that make up the northern main island. These sediments are interpreted as beach sands overlying and transi­ and incipient beachrock); tional to reef flat deposits. (5) Islands along the east (windward) side of atoll (a) Beach sands (4 samples) INTRODUCTION (b) Material from pits having depths from 20 Onotoa Atoll is a "dry" atoll (referring to its rainfall inches to 11% feet. The pits start in beach [Cloud, 1952, p. 10-15]) in the southern part of the sands, in which many of the specimens are Gilbert Islands. It is elongate northwest-southeast severely corroded (13 samples), and pene­ and bordered nearly continuously on the northeast trate through progressively richer transi­ (windward) and south sides by narrow islands but either tional sediments (7 samples) into sedi­ open to the ocean or protected by discontinuous living ments of a reef-flat horizon (3 samples). 171 172 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

EXPLANATION O Foraminifera locality, showing per­ centage 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 u.s.o.s. loc. No. Field localities and descriptions The following locality and sample descriptions, taken shore) end of lagoon-side jetty at Govern­ from P. E. Cloud's field notes, are arranged in order of ment Station and 660 ft inshore from sea beach along line bearing S. 87° W. at Pacific their U.S. Geological Survey Foraminifera locality Science Board campsite. Pit similar to numbers. They include pertinent details of the various GOC-1. Pit section in descending order, environments from which the Foraminifera from Onotoa with unit thicknesses, is: Atoll, Gilbert Islands, were derived. f11644. GOC-2A. Medium- to fine-grained limesand, dark brownish gray from organic matter. U.S.G.S. loc. No. Field localities and descriptions Worn Calcarina about 60 percent; remainder of detrital fines. Roots uncommon. Some fl!639-fll643. GOC-1. Southern part of northern main island, about 1,100 ft S. 41° E. from east stones as much as three-fourths of an inch in (inshore) end of lagoon-side jetty at Govern­ diameter. Top 5 in. GOC-2B. Medium-grained limesand. Worn ment Station and 325 ft inshore from sea beach f11645. Calcarina about 70 percent with occasional along line bearing S. 87° W. at Pacific Science pebbles as much as three-eighths of an inch Board campsite. Pit in which water level in upper 7 in. Up to 95+ percent worn fluctuated with tide. Pit section in descend­ Calcarina below. Remainder is detrital ing order, with unit thicknesses, is: fl!639. GOC-1 A. 99+ percent medium-grained Cal- CaC03. Tan to flesh colored; darker above than below. Roots abundant, as much as carina sand, dark brownish gray from organic three-eighths of an inch in diameter. Thick­ matter. Roots very abundant, up to seven- eighths of an inch in diameter. Foraminifera ness, 19 in. worn or eroded by organic acids. Subaerial f 11646. GOC-2C. Loose CaC03 gravel composed of 50 percent CaCOs pebbles as much as 2J4 in. accumulation?. Top 9-10 in. long and 50 percent worn Calcarina and f 11640. GOC-1B. 99+ percent medium-grained dark- tan Calcarina sand, abruptly gradational to detrital CaCOs. Roots abundant, as much as one-fourth of an inch in diameter. Thick­ f 11639 (GOC-1 A). Sample f 11640 differs only in organic content, abundance of roots, ness, 11 in. and good preservation of Calcarina, suggest­ f11647. GOC-2D. Strongly indurated flesh-colored ing only slight transportation. Roots mod­ granule sandstone, of varied detrital CaCOs. erately abundant, as much as one-half of an One loose sand layer 2-4 in. from base. Roots inch in diameter, cutting off abruptly at very rare. Thickness, 15 in. base. Subaerial accumulation?. Thickness, f 11648. GOC-2E. Very fine grained flesh-colored 16-17 in. detrital limesand. No roots. Thickness, fl!641. GOC-1C. Similar to fl!642 (GOC-1D), which 6 in. follows, but has alternating layers of semi- f11649. GOC-2F. Zone of Heliopora. Essentially indurated to indurated material. Basal 1-4 same as fl 1643 (GOC-1E). No roots. Reef in. indurated. Roots rarely extend into unit flat horizon? Thickness, 51 in. C. Probably deposited along beach near fl!650-fll653. GOC-3. Southern part of northern main reef flat. Thickness, 7-10 in. island, about 870 ft S. 3° E. (true) from east fl!642. GOC-1D. Weakly indurated to nonindurated (inshore) end of lagoon-side jetty at Govern­ medium-grained limesand, 80 ± percent well- ment Station and 340 ft inshore from lagoon preserved Calcarina and 20 ± percent other beach along line bearing N. 87° E. through Foraminifera and detrital CaCOs, much of Pacific Science Board campsite strip. Pit it quite fine grained. Other Foraminifera similar to GOC-1 and GOC-2. Pit section include Marginopora. Color is light tan to in descending order, with unit thicknesses, is: flesh. Thickens where fl!641 (GOC-1C) thins and unit C apparently represents in­ f11650. GOC-3A. Dark-brownish-gray organically en­ cipient beachrock at top of unit D. No riched limesand similar to f 11644 (GOC-2A). roots. Probably deposited along beach near Roots common. Top 8 in. reef flat. Thickness, 14-17 in. f11651. GOC-3B. Similar to f 11650 (GOC-3A) but fl!643. GOC-1E. Zone of Heliopora. About 70 per­ with less organic matter and only dark-tan cent blue coral of which much may be but to light-brown color. Roots abundant as none is certainly in position of growth; 30± much as one-half of an inch in diameter. percent interstitial limesands are coarse to fine Subsoil. Thickness, 6 in. grained, light tan to flesh, of detrital CaC03 None. GOC-3C. Medium-grained flesh-colored (pink­ and Foraminifera. MarginQpora abundant; ish-tan) limesand with occasional granules Calcarina common; echinoid spines occa­ and small pebbles (to one-half of an inch in sional. Interpreted as reef-flat horizon, built diameter). Mostly 90 percent worn and up to about low tide level and then overrun smooth Calcarina but with occasional Foram­ by beach of f 11642 (GOC-1D). No roots. inifera of other sorts, echinoid spines, algal 16 in. above watermark. Thickness, 25 in. fragments, small mollusks, and detrital fl!644-f11649. GOC-2. Southern part of northern main CaCOs. Many roots, upper part. Thick­ island, about 940 ft S. 25° E. from east (in- ness, 38 in. 174 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

U.S.O.S. loc. U.S.O.S. loc. No. Field localities and descriptions No. Field localities and descriptions f 11652. GOC-3D. Similar to GOC-3C but has fairly fl!660-fll661. GOC-17. Central part of northern main numerous pebbles (one-half of an inch maxi­ island, about 2,100-2,200 ft due east from mum diameter) and granules; small gastro­ Buariki Maneaba. Area of fine clastic limesilt pods relatively common, and Marginopora on which water lies close to surface, hard- common. Thickness, 20 in. pan tends to form, ground water is brackish, None. GOC-3E. Pinkish-gray granule gravel of and soil is generally poor. Pit section in fragmentary ramose calcareous algae with descending order, with unit thick-nesses, is: interstitial Calcarina sand (worn smooth). f11660. GOC-17A. Fine medium-grayish-tan limesand Thickness, 10 in. and limesilt. Many roots as much as three- fl!653. GOC-3F. Similar to fl!652 (GOC-3D). eighths of an inch in diameter. Few Cal­ Thickness, 40 in. carina. Top 9 in. None. GOC-3G. Zone of large head-forming crustose f!1661. GOC-17B. Light-tan medium-grained lime- corallines and occasional astraeiform corals sand, 10-15 percent Calcarina. Roots main­ and interstitial sand like f 11652 (GOC-3D) ly in top inch or two but some to bottom. and f 11653 (GOC-3F). Only algae and Thickness, 15 in. corals sampled. Thickness, 8 in. fl!662. GOC-19. Beach sand on the northwest shore None. GOC-3H. Similar to fl!652 (GOC-3D) and of islet of Nanntabuariki. Excellently pre­ f 11653 (GOC-3F). (Field observation, no served Baculogypsina and Marginopora sample taken.) Thickness, 8 in. washed in from adjacent reef flats to north fl!654-f 11655. GOC-4. North-central part of northern main and east. island, about 1,000 ft east-northeast from fl!663-f11664. GOC-20. Southern main island, section above Taneang-Tekawa Maneaba. Section in area beach just south of Otoae village Maneaba, of fine clastic limesand that makes fine­ lagoon shore. Section in descending order, grained loamy soil at this place dry. Pit with unit thicknesses, is: section in descending order, with unit thick­ f11663. GOC-20 A. Limesand, 20 ± percent Calcarina, nesses, is: scattered pebbles as much as 2 in long. Top f 11654. GOC-4A. Very fine grained brownish-gray 24 in. (from organic matter) limesand; grades down f 11664. GOC-20B. Shell bed, limesand (50 percent to fl!655 (GOC-4B). Roots common, as Calcarina) matrix small Cardium most much as five-eighths of an inch in diameter. abundant. Goes laterally to a pebble gravel. Top 10 in. Thickness, 6 in. f 11655. GOC-4B. Pinkish-yellow clastic limesand None. GOC-20C. Limesand, 40-50 percent Calcar­ mostly fine grained, with <10 percent ina, occasional pebbles as much as 2 in long. Calcarina but local patches contain abundant Thickness, 15 in. Calcarina. Only occasional roots in upper fl!665. GOC-27. About 9,200 ft S. 72° W. from off­ part. Thickness, 26 in. shore end of Government Station jetty (on fl!656. GOC-5. North-central part of northern main southern part of northern main island) just island, about 1,700 ft northeast from Tane­ south of main passage out of lagoon (Rawa ang-Tekawa Maneaba. Area of pebble coral ni Karoro) where coral shoals known as Aon gravel with interstitial limesands. Stonv te Rabata begin to deepen. Collection from and hard to dig. Dug down only 20 in., of area where reef knolls and patches rise above which top 10 in. is organic-rich, brownish- the limesand bottom at 16 ft depth. Most gray soil with plentiful roots. Lower 10 in. specimens from a low coral patch about 14 pinkish yellow. ft below the surface. fl!657-f 11659. GOC-6. North-central part of northern main fl!666. GOC-28. Slightly less than 4 miles N. 85° W. island, about 2,400 ft north-northeast from from Aiaki Maneaba in outer lagoon. Reef Taneang-Tekawa Maneaba. Section in area patches and knolls rising above limesand of fine clastic limesands locally with thin bottom (at 14 ft) to within 6 ft of water gravel veneer at surface and locally of old surface. Fish taken from on and near reef dune sand material near shore. Pit section knolls and sediment taken from bottom. in descending order, with unit thicknesses, fl!667. GOC-29. About 1 mile S. 32° W. from Tekawa is: church at lagoon margin of south end of reef f 11657. GOC-6A. Organic-rich, dark-gray-brown lime- stretch known as Aon te Baba. Collection sand, 20 ± percent worn Calcarina, few small from reef patches rising above limesand pebbles (as much as one-half of an inch in bottom (at a depth of 9 ft reduced to mean diameter), many small roots. Top 6 in. low tide) to within 1 ft of surface. Much f 11658. GOC-6B. Dark-tan limesand, 30-40 percent Halimeda, many sheetlike crustose corallines worn Calcarina, many roots as much as one- red on under sides. Limesand very fine to half of an inch in diameter; no pebbles. limesilt at centers of open areas. Thickness, 10 in. fl!668. GOC-30. Heliopora flat at south end of the f 11659. GOC-6C. Flesh-colored medium-grained lime- northern main island. At +1 ft low tide, sand, 10-25 percent badly worn Calcarina. tops of living Heliopora and few Porites lobata Thickness, 14 in. seen were just flush with water surface. FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 175

U.S.G.S. toe. U.S.G.S. toe. No. Field localities and descriptions No. Field localities and descriptions £11669. GOC-31. Southeast end of northern main north end of reefy shoal area known as Aon island. Scrapings from green algal crust te Rabata. Coral patches rising to within on inner flat of windward reef about midway 5 ft of surface from lesser (30-50 percent of out (east) on reef flat from center of cove at area) intervening areas of limesand bottom, southeast end of island. Sediment-binding 12ft. green algae are matted with Baculogypsina, fl!679. GOC-49. About 12,000 ft S. 63° W. from Marginopora, and other Foraminifera. lagoon end of Government Station jetty, on fl!670. GOC-33. About 7,100 ft S. 50° W. from the seaward side of the north end of a reefy Tekawa church at seaward edge of Aon te shoal area known as Aon te Rabata, in patch Baba reef north of main boat passage. Reef reefs rising to within 6 ft of surface Lime- area is broad and irregular, fronted seaward sand bottom at 18 ft deep. by area of limesand 18 ft deep at midtide or £11680. GOC-51. About 3^ miles N. 31° W. from about 15 ft reduced to mean low tide. (At Tabuarorae Maneaba near center of Te collecting locality reef itself at general depth Rawa ni Bao, a pass in south part of leeward of 3 ft at mean low tide, with holes to depth reef. Collected from thickly set coral masses of 8 ft at mean low tide.) Medium-grained rising from 15 ft (sounded at low tide) of limesand with ripple marks parallel to reef water to within about 8-10 ft of surface front. Slopes gradually seaward with off- locally. Bottom of coral-algal rock anc' lying reef patches. living corals and algae with minor pockets of fl!671-f 11672. GOC-35. About 8,600 ft N. 18° W. from very coarse limesand and calcareous gravel. Tabuarorae Maneaba in 17 ft of water at Sediment sample taken in shoal area lagoon- mean low tide. ward in about 3 ft of water from hole con­ fl!671. GOC-35a. South bottom sample. taining coarse limesand and gravel. fl!672. GOC-35b. North bottom sample. Area of fl!681. GOC-52. About 12,000 ft N. 30° W. from many coral patches on limesand-gravel Tabuarorae Maneaba at south end of Rakai bottom. Anchored for first sample (f 11671 ni Make, a reef area in southern part of GOC-35a) of limesand-gravel over an area leeward reef. Collected corals, algae, mol- richly floored with red bushy crustose coral­ lusks, and sample of coarse limesand and lines, but dragged anchor and drifted north­ gravel, the latter from a hole in about 3 ft west about 100 yd where collected second of water. bottom sample (£11672, GOC-35b) of rela­ f 11682. GOC-53. About 9,300 ft N. 30° W. from tively pure limesand. Tabuarorae Maneaba in southern part of fll673-f!1674. GOC-36. Southeast end of reef area known as Te Rawa Tekatobibi, a pass through south Rakai Ati (south side of big westward point end of leeward reef. Collected from coral of reef near center of atoll). A flourishing patches and knolls rising to occasional maxi­ reef; collection from reef flat northeastward mum of within 4 ft of surface from a bottom in shoal waters, from strip about one-half of sounded at 18 ft. a mile long running clear across the reef. £11673. GOC-36a. Seaward or southwestward ±500 fl!683 GOC-55. About 13,400 ft S. 75° W. from ft is area of much coral in small and large Aiaki Maneaba in deep central part of the patches with interspersed coarse limesand lagoon. Impalpably fine limemud from having a considerable gravel fraction of bottom of low scattered dead and living granule and pebble size. coral patches on intervening limemud and fl!674. GOC-36b. Lagoonward or northeastward limesand about 30-40 percent sediments and ±500 ft is mostly sand with scattered coral 60-70 percent coral. patches. fl!684. GOC-56. About 8,300 ft S. 76° W. from fl!675. GOC-37. About one-third of the distance Aiaki Maneaba on reef patch in the central between the north point of the reef area lagoon. Complex mass of living coral known as Rakai Ati and the east end of with patches of limesand and fine gravel on Rakai Maneku, at inner part of point of reef surface, perhaps 150-200 yd in diameter, that projects westward from near the center rising from surrounding bottom of ± 18 ft. of Onotoa Atoll. Sediment sample taken from Depths on knoll 4-10 ft at mean low tide, hole about 10-12 ft deep. with coral heads rising to within 1 ft of fl!676. GOC-38. Lower beach at southwest corner of surface. Sediment sample from mean low Tebaki, north end of northern main island. tide depth of ±6 ft. Sandy lagoon beach. fl!685. GOC-57. About 7,500 ft S. 80° W. from f 11677. GOC-45. Area of Thalassia patches on coarse Aiaki Maneaba on reef patch in central limesand bottom off northwest end of outer lagoon. Habitat, bottom types, and depth rib of elevated beachrock at north Tekawa, range similar to f 11684 (GOC-56), but much northwest Onotoa Atoll. more limesand and less coral. Depth of fl!678. GOC-48. About 10,000 ft S. 62° W. from sediment sample at ±6 ft at mean low tide lagoon end of Government Station jetty at datum. 176 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

U.S.O.S. loc. No. Field locations and descriptions 3. Reef areas f 11686. GOC-58. About 3,600 ft S. 80° W. from 4. Islands along east side of atoll. Aiaki Maneaba on reef patch in central In the last category are included both modern beach lagoon. Generally similar to f 11684 (GOC- sands and material from a series of dug pits inshore 56) and f 11685 (GOC-57) but smaller and from the sea beach. Samples from the pits are grouped deeper and contains even less coral than f 11685 (GOC-57). Bottom at ±10 ft at according to similarity of composition and in order mean low tide datum, with patchy coral. of increasing variety of species. With this arrange­ Collected bottom sample at 15 ft mean low ment, the samples fall into three subdivisions: those tide datum from lim'esand slope leading off interpreted as beach sands, those interpreted as reef to slightly deeper water. flat sediments, and those transitional between these two f 11687. 51-L-8. Southeast end of Tabuarorae islet corresponding to Aontebeke land area. types of deposits. Weakly bonded limesand along beach. As the Onotoa species are nearly all well known and fl!688. 51-L-9. Southwest end of Mangaia land area, well illustrated (Cushman, Todd, and Post, 1954; Todd, Tabuaurorae islet. Low, narrow north- 1957; Todd and Low, 1960), complete formal descrip­ trending ridge in area of lush vegetation, tions are not included in this report and only a selected apparently most easterly of a set of older dunesand ridges ±500 ft long, about 60 ft few are illustrated. In a later section, certain species across from intertrough to intertrough. Only that are not found in these three Professional Papers one of set that seems phosphatic. are discussed and selected references included for them. f 11689. 51-S-5. Central Tabuarorae islet. West end Major constituents of the Onotoa fauna are: of tidal flats encircled by islet. fl!690. 51-S-6. Tabuarorae islet. Near center of Amphistegina madagascariensis d'Orbigny north arm of tidal flats encircled by islet. Baculogypsina sphaerulata (Parker and Jones) fl!691. 51-S-7. About 4,400 ft N. 86° W. from Calcarina spengleri (Gmelin) northwest corner of Abanekeneke, sediment Elphidium striato-punctatum (Fichtel and Moll) taken in about 14 ft of water at mean low Homotrema rubrum (Lamarck) tide datum. Heterostegina suborbicularis d'Orbigny fl!692. 51-S-8. About 1,400 ft S. 60° W. from lagoon Marginopora vertebralis Blainville end of Government Station jetty. Drag Besides these, the following species, although they make sample of limesand bottom between sparse up negligible amounts of the population, are found in dead and living coral, taken in about 9 ft of water at mean low tide datum. most of the samples except the beach sand: f 11693. 51-S-9. About 4,200 ft S. 79° W. from lagoon Acervulina inhaerens Schultze end of Government Station jetty. Fine Cibicidella variabilis (d'Orbigny) limesand bottom at 20 ft depth at mean low Cornuspira planorbis Schultze tide datum. Patches of growing coral Cymbaloporetta bradyi (Cushman) mostly to about 10-15 ft in diameter anr C. squammosa (d'Orbigny) only 1-2 ft above bottom. Elphidium advenum var. dispar Cushman f 11694. 51-S-10. About 3# miles N. 30° W. from E. crispum (Linn£) Tabuarorae Maneaba. From coarse- to Gaudryina (Siphogaudryina) rugulosa Cushman medium-grained limesand bottom about 10 ft Haddonia torresiensis Chapman deep with coral pinnacles rising to within 6 ft Neoconorbina patelliformis (Brady) of surface. Planorbulina acervalis Brady fl!695. 51-S-ll. About 4,600 ft S. 65° W. from Pyropilus rotundatus Cushman lagoon end of Government Station jetty. Quinqueloculina polygona d'Orbigny Limesand bottom of reentrant or depression Reussella simplex (Cushman) in large lagoon reef patch. Rosalind candeiana d'Orbigny Schlumbergerina alveoliniformis (Brady) f 11696. 51-S-12. West side of Tebaki, northwest Siphogenerina raphana (Parker and Jones) Onotoa Atoll. Center of clean limesand Spirolina arietina (Batsch) area between southwestward extending lime- Spiroloculina angulata Cushman sand spits. Tretomphalus concinnus (Brady) T. planus Cushman FAUNA Triloculina irregularis (d'Orbigny) A total of 168 species and varieties have been found T. oblonga (Montagu) in the Onotoa samples. In table 1 the samples are The remaining 138 species and varieties are rare for grouped, according to similarity of environment, in the the most part, and their occurrences are scattered or following categories: single occurrences. Among them, however, are a few 1. Area open to ocean on west (leeward side) species whose distribution shows a restricted, and pos­ 2. Lagoon sibly 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]

Lagoon Reef areas From islands along east side of atoll

Area open to Southern Pits inshore from sea beach (see text fig. 1) ocean on west part of (leeward side) Central and i atoll Beach Southern northern Leeward 3 sands Inte Interpreted as beach sands Transitional prete 1GOC-30, . sediments as re flats

< M < M GOC-35a GOC-35b OQ oo 9 GOC-36a GOC-36b < «! n n « ( O Q W H GOC-33 *? GOC-48 GOC-49 GOC-37 GOG-53 GOC-56 GOC-45 GOC-52 GOC-31 GOG-38 GOG-19 7* GOC-3A GOC-3B GOC-3D GOC-3F GOC-4A CD GOC-6C GOC-4B o ? ? ? 1 7 T i i ? i ? ? T ? f 51-S-12 f ? i ? 7 ? O ? O O o O CO CO g § O O O o o o o 0 O O O o O ^ i 4 O ? 5 j^ 0 O O o 0 o 0 o 0 o O 0 0 O 0 0 0 O O O O o o i>o 2>o >o "O >o o >o 3 ?E3 >o O O O o O o o o O O O o O O O o o

Hy peramminidae : R R Lituolidae: R Textulariidae: tel R R R R R R R R R R R R R R R R R R ...... R __ R __ R R R R R R R ? R R ? R R R R ? R R R- R R R Verneuilinidae: R (Siphogaudryina) rugulosa Cushman (pi. 25, fig. 5b) _ R C C R C C A -- -- R R C R R C R r R R C R R R R _. R R Valvulinidae: R R R R R R R R R R R R R R R C R R R R R C - R R R Miliolidae: R R R R R ? R R R R R R R R R C R C R R R R R R R R R R R R R R R R R ? ? R R C R R R R R R, R O R R R R R 9 r1 R .. R R R R R R R R -- R R R R R R R R R, R R r R R R R R R, C R R R A A R, R R R R R R R R R n R R R R R R C R R -- R -- R -- R -- R -- R R ------R ------R R R R R R R R R R R R R R R R ? R r, R R R R C r R, A A R A R R R R R R R R, R R R R R R R R R, R C R -- -- R R R R c C R R C C A C C A C C R R C R R R R - R R R R R R R R -- R R C R R, R R R R R R R R R R .. R R R R R R R R R, r R R R 0 R R R C R A C R R R n R f R, R R.. R R R -- R -- R R R R R R R A R R R -- R R ------R R R R R R, R c R R C A A C C C R ? R R R ? R R R R .. R R R R R R .. R R R R R R R R R R R R r, R r R f R R R R - R R R R C C R R R R R r, R R n R R R R ? R R R R R R -- R R R R R R R R R Massilina planata Cushman. ___ .. ___ . __ __ ... R R R R R R 178 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

JS-OOO PS PSPSP3 PS PS IPSP4 0 PSP4 P5-«J PS as-ooo PS 0 as PS PS :-

CTTOSTTTBTITTAt1eamniiaftm. ...------_- (pi.figs.?22,3,4;pi.flg.5d)_...... 25,sp...... Heterosteginasuborbicularisd'Orbigny(pi.flg.5a)25,__. "RS a a> azi Bolivinellafolium(ParkerandJones)...... Buliminoideswilliamsonianus(Bradv)....__ Fissurinalacunafa(BurrowsandHolland)... MarginoporavertebralisBlainville-__--..... &£ PlacopsilinabradyiCushmanandMcCulloch d'Orbignyproteus(pi.7)flg.22._____ FischerinapellucidaMillett(pi.flg.6)22, Sigmomorphinaterguemiana(Fornasini). BuliminellamillettiCushman_.._____ ">>' Peneroplisellipticusd'Orbienv...._... "£ Soritesmarainalis(Lamarck)__. Ifg a ^ "c1 a BdelloidinaCarter..aggregata...... Spirolinaacicularis(Batsch).___. c« t- 08 S-M lH fa >. S3 MonalvsidiumvolitumChaDman Borelispulchrus(d'Orbigny).. 1 .Ss'S « (£ i"ia co" BE HaddoniatorresiensisChapman. ^ H5 a -2 0. Parrinabradyi(Millett). a£ 'i'ii R'B £ a le 5- £ "5. o2-S c ^a s s o arietina(Batsch) "'}W22iw ppoj, a* >s&§> a J? » 2 e ' !? H w egoill3 ^.S s o 2 ..-S >-a » IS 05 0. CH s If III 3 j cd § OP« s.~ a oe _e s "52, 3 -a « .s~ Polymorphinidae: o e si 111 ^ S ^ S :S-fc ._~ Alveolinelliclae: Heterohelicidae: s^«. a-,1 T3 C Fischerinidae: Placopsilinidae: Peneroplidae: Ls oES'S 2'§ -§ S S .1S §. Camerinidae: Buliminidae: §'3 5 *^ Qj «~ S il S 's 2 S a ao « rS 0 1 St: *- PTO **. B k || 00^^ 1 3 c: sa S^r o. 1 O FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 179

^P?D P?P? P5 P?P? P?P? P5 P5 P5P5 P? P5 P?=- P50P5 o 0 *4 P5DP.P50 i?P?D P? P?P? P5P5P5 P5P?ff P?P? A ft

P?pc P5 P? 0 p: j 25 «) «) P? Pi P5 P? P? PC D <. P5 P? P?p: P p; PC PC ft P5 Iff £ -3 -3 P5C P5 M aj P5 «<) p! P? D «. 1 D «. ! D -. I 0

CushmanandWickendensubexcavata...... Amphistegina6).madagascariensisd'Orbigny(pi.figs.4,25, (Millett)rhomboidalis_____- .. Cushmanstriatula ....._-.. ..__-__. tortuosaJ.raay------__..- Cushmanmavori(Loxostomum) . _ ... (Cushman)--Eeussellasimvlex ___-. .... Chapmanfig.5)..denticulo-granulata(pi.23, -..-- striato-punctatum(FichtelandMoll)_____..__- Tretomphalus(Brady)fig.concinnus(pi.4)24,...... _. EpistominellatubuliferaEarland)(Heron-Alienand...... fig.dimorpha(Brady)(pi.10).-Chrysalidinella22,___.. BradySmrillinadecorata___------.._____. inaequalisBrady------___- ... Rhumbler.vivivararevertensvar...... Oushman..Conicosmrillinatrochoidea-...... PatellinaadvenaCushman....._...._...... _... orientalis(Cushman)-_--_--._----_------.------Neoconorbinafrustata(Cushman)---....-...... -.__--- Peaidiadubia(d'Orbienv')----...._.... Bacvlogypsina(ParkerandJones)sphaerulata(pi.25, fles.1.2).-______limbataBradv---...(Loxostomum'} ____._. BradyUvioerinavorrecta .- EhrenberEvivivara .__..._- .. tuberocavttata(ChaDman)-.______-___.. andEpistomaroidespolystomelloides(ParkerJones)__... Elvhidium(Cushman)...advenum______.... b/j PyropilusrotundatusCushmanfig.9)..-(pi.22,_____ Jones)..andSiphogenerina(Parkerraphana___.... UchioPoroeponidesandcribrorepandusAsano_.__ C SphaeridiapapillataAlienEarland---Heron-and_____ Calcarina(Qmelm)spenglerifigs.7-9)(pi.25,_____... Attiatinatranslucensfig.(Oushman)2)(pi.23.__._ (Brady)concinna _-.-. .--... m~ Cymbaloporettabradyi(Cushman)_------8)_.fig.Eectobolivina''.(pi.22,sp....__..,_.. Cushman...altiformisadvenavar.______..... (Cushman)beccariitemda______.... Cushman..advenumdisparvar.______.__ ^ IN NonionellaTodd.1957sp.______planusOushman(pi.fig.6)24,______..____ "«! 3 a ">, Jj£ C abj; 2 1PC C C Tt< 00 1 5 2- c CO a "a < ~i Pj iJS S S c

553580 O 61- 180 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

as-ooo P"3PH « PnPn 4 Pd i 0 sto *" ts PH PH PH PH 3d PH PH PH C S MC as-ooo M a« ai-ooo PH PH 13 03P Pd 03 ! as-ooo PH PH Pd PH 3d P3 PH 0 tf PH O ch(seefig.1)text Transitional ai-ooo sediments os-ooo tf Pd OT-OOO PH 0 azi-ooo PH PH 03 VZT-000 | islandsFromalongsideofatolleast a^-ooo PH PH ] as-ooo PH PH i3 PH si-ooo PH inshorefromPitsbeasea O9-OOO PH 0 Interpretedbeachsandsas 39-000 V9-OOO s-ooo v*-ooo as-ooo PH a s-ooo PH 0 98-OOO Pd vs-ooo vs-ooo vi-ooo aoz-ooo (i3 « Pd Pd Pi § vos-ooo 03 PH IS 6T-OOO O 03 P3 0 fl PQ M o 8S-OOO pel Pd Pd O O "«M 9-S-IS 13 s-s-is 6-q-is o a QD 8-a-is PH PC c^ 13 pi^puiA, TS-OOO PH Reefareas os-ooo PH V 8 Q9S-OOO « Pd Pd 4 P3 PS pel O B9S-OOD 33 P3 Pd ss-ooo PH f« pel PH K M M 0 < Pd o 2I-S-IS p: PH PH I Pd Pd ad ! andCentral s^-ooo i northern 6S-OOO tf tf C3 PC Pd o o Pd PH ! TT-S-TS 33 : Pd PH ! 6-S-TS f Pd PS 33 M M 03 8-S-TS pj ! Pd ! Pd ao z-s-is tf 1 PH Pd ! OT-S-TS 33 P3 Pd Pd Pd 1 8S-OOO 33 ! tf Pd Pd o Southern 8S-OOO 33 ! ! I zs-ooo tf 33 P3 PH PH 9S-OOO pel pel PH M ! ss-ooo pel PC PH PH PH qss-ooo J5 PS PH PH egg-oQO PS I PH 1 ES-000 V. 15 Pd PC PC pel Pelfd«pc; Pd < 8 |,§ TS-OOO X PH PC M ; ! M O C ? £ PC 0} zs-ooo PC Pd Pdo PH PH 6^-000 PC PC 0 PC PC PH Pd oc«PdPdpe PH < PC PH P«3O PH ft p5 £ D O 8^-000 PC c- < ^ OCJ zs-ooo PC pel PC Pd ««pc O 88-000 PC PC PH 33 PH 03 » 0 0 03 O

Yruoraaoroigny. ------.----. Jones)(pi.(Parkerand24,Pulleniatinaobliquiloculata (Cushman)--.pseudoumgerianuscf.C...... - (d'Orbigny).-...----Cibiddellavariabilis----- .--- vesicularisandJones)(Parker_------__...-- fig.3)..(Egger)(pi.24,Globigerinataglutinata... fl?.2)d'Orbigny?(pi.24,Orbulinauniversa...... BradyacervalisPlanorbulina...-_..-.--..--._-- __. . ruber(d'Orbigny)- (Brady) sacculifer ------___ andJones)(ParkerPlanorbulinoidesretinaculatus b (Brady)conglobatusGlobigerinoides (Lamarck)rubrumHomotrema ff?s '<£ 2 1 i 13 I* a: >c il p HTlrhiomvhiijlnijvs,fUn^narSmn i- 3 II ii i ^ ^t- IT a c si il li il- o [i: 11 11 3- 3.1 \\N Planorbulinidae: Homotremidae: il* ! 11 Globigerinidae: k Anomalinidae: s ; !l ' Is! fl So 5 !l i FORAMINIFERA FROM ONOTOA ATOLL, GILBERT ISLANDS 181

The species Textularia joliacea Heron-Alien and processing may affect the apparent live-dead ratio. To Earland, with its variety oceanica, appears to be re­ me it seems doubtful that it had an appreciable effect stricted to the central deeper part of the lagoon where on the Onotoa samples, as the stained specimens the bottom is covered by fine to coarse limesand between observed were mostly very clearly and unmistakable patches of coral. Streblus beccarii (Linne) is a large stained. robust form unknown in typical form in the Marshall On table 1, the record of live specimens is indicated Islands but is found fairly commonly around Saipan by the abundance symbol being printed in bold face. Island. At Onotoa Atoll it is present in some of the An A or C printed in bold face does not of course mean lagoonal sediments. It probably is not a reef dweller. that the live specimens were abundant or common, but The rare occurrences of Bolivinella folium (Parker and merely that among the abundant or common specimens Jones) are all from limesand bottom in the central part were some live (stained) ones. of the lagoon. With the stained individuals forming so small a Examples of the Foraminifera typical of the limesand percentage of the total specimens present, it is not bottom of the lagoon are illustrated on plate 25, figures unreasonable to assume that evidence for these live 4-6. specimens would be frequently missed. This assump­ In general, the Onotoa fauna shows rather close tion may be the explanation for the "lack" of stained correspondence in species composition to the faunas of specimens of a particular species in certain samples other areas of the central Pacific. Comparisons with where unstained specimens of that species are common shallow-water faunas around Saipan, Mariana Islands, to abundant. The following common to abundant (Todd, 1957), and inside the lagoons of four atolls species are those of which living specimens probably (Bikini, Eniwetok, Rongelap, and Rongerik) in the occurred but were missed in the samples studied. northern Marshall Islands (Cushman, Todd, and Post, Amphistegina madagascariensis d'Orbigny 1954) are of interest. At Saipan the material was Baculogypsina sphaerulata (Parker and Jones) collected from depths mostly not greater than 38 feet Calcarina spengleri (Gmelin) depths comparable to those at Onotoa which were Cymbaloporeita bradyi (Cushman) C. squammosa (d'Orbigny) mostly shallower than 20 feet. In the Marshall Islands Elphidium striato-punctatum (Fichtel and Moll) most of the samples came from depths greater than 60 Heterostegina suborbicularis d'Orbigny feet. No striking differences in fauna were observed Marginopora vertebralis Blainville between Saipan and Onotoa when the rarer occurrences Schlumbergerina alveoliniformis (Brady) from each area are left out of consideration. In the Spirolina arietina (Batsch) Marshall Islands, on the other hand, where the material The assumption that specimens of the foregoing species came from significantly greater depths than did the lived where they occur commonly to abundantly seems, Onotoa material, three species that are unknown at therefore, a safe one. Onotoa are present with more than scattered occurren­ The two major distinctive habitats that are recog­ ces. Their absence at Onotoa may signify an upper nizable at Onotoa on the basis of the relative abundance depth limitation for them, somewhere between 20 and of species in the sediments are the surfaces and slopes 60 feet. The species are Operculina ammonoides of reefs and the limesand bottom of the lagoon. Presence (Gronovius), Calcarina hispida Brady, and Anomali- and absence of stained specimens (that is, collected as nella rostrata (Brady). living individuals) of certain species in samples from these two areas confirms the distinction between these WET SAMPLES two habitats. The major inhabitants of reef surfaces Twenty-four of the Onotoa samples were treated and the slopes adjacent to reefs seem to be (in order of with alcohol when collected in 1951 and preserved wet abundance): in order that distinction between living specimens and Calcarina spengleri (Gmelin) empty tests would be possible. By this means an esti­ Baculogypsina sphaerulata (Parker and Jones) mate of which species actually lived in various locations Amphistegina madagascariensis d'Orbigny Marginopora vertebralis Blainville and which species may have been deposited there as Cymbaloporetta bradyi (Cushman) empty tests could be made. C. squammosa (d'Orbigny) In the spring of 1957, after approximately 6 years, The major inhabitants of the limesand bottom of the the samples were processed by staining in rose bengal lagoon seem to be (in order of abundance): solution as described by Walton (1952, p. 58), Rela­ tively few specimens (such as of the order of 1 percent) Amphistegina madagascariensis d'Orbigny Heterostegina suborbicularis d'Orbigny gave a positive reaction to the stain. It is unknown Marginopora vertebralis Blainville whether or not a 6-year interval between collection and Spirolina arietina (Batsch) 182 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Cymbaloporetta bradyi (Cushman) long. However, in other less firmly or less permanently C. squamosa (d'Orbigny) attached forms, such as Planorbulina and Acervulina, Elphidium striato-punctatum (Fichtel and Moll) staining proved that at least some of the detached Schlumbergerina, alveoliniformis (Brady) specimens were still alive when collected. Minor inhabitants of the limesand floor include four large arenaceous species, Valvulina davidiana Chapman, EXAMINATION OF FISH CONTENTS Haddonia torresiensis Chapman, and the two large Stomach and gut contents of 22 fishes were examined species of Oaudryina (Siphogaudryina) a variety of for their Foraminifera, and many species were found in miliolids; the peneroplids Peneroplis ellipticus d'Orbigny several of them (table 2). The fishes fall into five and Sorites marginalis (Lamarck); several buliminids groups as follows: including Reussella simplex (Cushman) and a few Trigger fishes: species of Bolivina; a few discorbids including several Nos. 2-4. Rhinecanthus aculeatus (Linnaeus) species of Rosalina and Neoconorbina; several species of 8. R. rectangulus (Bloch and Schneider) Elphidium; a few forms belonging in the Cymbalo- 5-7. Ralistapus undulatus (Park) poridae (Pyropilus rotundatus Cushman and two species 20. Melichthys bunvia (Glinther) of Tretomphalus) and several species of the families Surgeon fishes: Nos. 16. Acanthurus gahhm (Forskal) Anomalinidae and Planorbulinidae that are usually 17. Ctenochaetus striatus (Quoy and Gaimard) attached forms. 18. C. cyanoguttatus Randall In addition, the following species are present as live Parrot fishes: specimens in the lagoon but seem to be locally restricted, Nos. 9-15. Scarus sp. their local restriction being obvious from the limited File fish: No. 21. Cantherines sandwichensis (Quoy and Gaimard) distribution of their empty tests as well as of stained Puffers: specimens: Nos. 22, 24. Arothron nigropunctatus (Bloch) Buliminoides williamsonianus (Brady) From Cloud's observations in the field (written Cassidulina minuta Cushman Epistomaroides polystomelloides (Parker and Jones) communication July 24, 1959), the feeding habits of Epistominella tubulifera (Heron-Alien and Earland) these groups of fish are as follows: Trigger fishes and Placopsilinal sp. surgeon fishes browse mostly on algae and coral, but Poroeponides cribrorepandus Asano and Uchio they also eat small echinoids and take in considerable Siphoninoides echinatus (Brady) amounts of the bottom sediment. The parrot fishes Spirillina (several species) Streblus beccarii (Linne) browse on algae, coral, and coral-algal rock, occasionally Textularia dupla Todd breaking off large chunks. The file fishes and puffers T. foliacea Heron-Alien and Earland seem to eat mainly coral. T. foliacea var. oceanica Cushman It can be seen from the occurrence table that a greater As for the remaining 76 species present in the 24 wet variety of Foraminifera species is found in the trigger samples, for which no evidence of living specimens was and surgeon fishes (in which the habit of taking in found, with but two exceptions the species are rare bottom sediment is present) than in those fishes that with scattered occurrences. One interpretation of these ordinarily browse only on the various plants and ani­ 76 may be that the specimens did not live precisely mals that grow up from the lagoon floor. where found and the empty tests were deposited there In general, a larger proportion of attached forms are after having been washed in from another, probably found in the stomach and gut contents than are found nearby, location. However, the possibility of missing in the bottom sediments. In only one sample, however, stained specimens, in assemblages where the species was any foraminiferal material obviously bitten off by in question occurs rarely, is very great. Thus a second a fish: a large fragment of Planorbulinoides retinacu- interpretation is that evidence of live specimens was latus (Parker and Jones) found in one of the trigger missed in many of these rare occurrences. fishes. Probably most of the specimens were taken in The two exceptions where species were not rare are as a part of the bottom sediment incidental to the Spiroloculina clara Cushman and Homotrema rubrum obtaining of other food. In some samples a large (Lamarck). Specimens of Spiroloculina clara were proportion of the specimens of Amphistegina still retain probably washed into their collecting localities as their light-green color and fresh appearance, suggesting empty tests. In Homotrema rubrum the red original they were living when taken in by the fish. color of the test would preclude recognition of any red The composite fauna from the several fish examined stain if present. Furthermore, it is unlikely that is one characteristic of shallow conditions. The most broken-off fragments of such permanently attached abundant species is Amphistegina madagascariensis forms as Homotrema would retain their protoplasm for 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

Trigger fishes Surgeon Parrot fishes File Puffers fishes fish

(BlochandSchneider) RandallC.cyanoguttatus sandwichensisCantherines nigropunctatusArothron aculeatusRhinecanthus Rhinecanthusrectangulus Gaimard)(Quoyand andGaimard)(Quoy Balistapusundulatus striatusCtenochaetus Melichthysbuniva gahhmAcanthurus (Linnaeus) (Gunther) (Forskal) a (Park) (Bloch) ie $3

2 3 4 8 5 5a 6 7 20 16 17 18 9 10 11 12 13 14 15 21 22 24

Textulariidae: Verneuilinidae: X Valvulinidae: X Miliolidae: X X incisurd Todd X X X X X X X X X y X

X X X X

X Ophthalmidiidae: X Parrina bradyi (Millett) .. ._._ .__. X Camerinidae: X X X X X X X X X X Peneroplidae: X X X X X X X X X X X X X X Buliminidae:

Spirillinidae:

Discorbidae: X X X X

X X Rotaliidae:

Elphidiidae: X X - X X X

Amphisteginidae : X X X X X X X X X X X X X X X X X X X Calcarinidae: X X X X X X X X X X X Cymbaloporidae: X X X X X X X X X X X X X X X X X X X .... Globigerinidae:

Anomalinidae: X X X X X X X X Planorbulinidae : X X X X X Homotremidae: X X X X X .... X X X X X X 184 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY shallow waters of the tropical Pacific. The next most a large proportion of reef-dwelling Foraminifera, such abundant species is Heterostegina suborbicularis d'Or- as Baculogypsina, Calcarina, and Marginopora, may be bigny. Abundance of these two forms is known to vary interpreted as being frequenters of reef flats and reef greatly from place to place, possibly for reasons related fronts. Other fishes, whose stomachs are free or nearly to gregarious habit of Foraminifera. Likewise, their free of those large genera, probably fed mostly in patch abundance varies greatly in the stomach and gut reefs and sandy areas. The observation that certain contents. Fish No. 15, for example, contained more fish had consumed large proportions of one or the other, specimens of Heterostegina than of any other genus of but usually not both, of the two major genera (Cal­ Foraminifera. carina and Baculogypsina} that inhabit the reef flats Miliolids are much more abundant than buliminids in suggests that individual fish may be quite restricted the samples under discussion. Peneroplids (except for in their food-gathering travels. Marginopora vertebralis Blainville, a species that appears Study of stomach and gut contents of sedentary to live more abundantly on the reef flats than on the animals might throw additional light on the probable bottom of the lagoon) are rare, and arenaceous forms dwelling places of various species of Foraminifera, are almost completely missing. Globigerinids are also whether on algae of various kinds, or on coral, or in very rare in the stomach and gut contents. Quite a the sands or muds of the lagoon bottom. large proportion of the specimens found in the stomach Table 2 gives the species of Foraminifera found in and gut contents are attached forms, such as Neo- the 22 samples of fish stomach and gut contents. In conorbina, Rosalind, Cymbaloporetta, Cibicides, Cibi- only three samples were species found in the fish that cidella, Acervulina, Planorbulina, Planorbulinoides, and were not also found in the bottom sediments: Homotrema. 1. Clavulina multicamerata Chapman in fish No. 2. In the bottom sediments, specimens of Tretomphalus It differs from C. angularis d'Orbigny in a are found in fair abundance; those with float chambers rounded cross section toward the apertural end accompanied by rather large numbers of the Rosalina- instead of a triangular section throughout. stages without float chambers. The morphogenetic 2. Triloculina terquemiana (Brady) in fish No. 3. relationship between these two forms was demonstrated 3. Eosalina rugosa d'Orbigny in fish No. 2. It differs and clearly illustrated by Myers (1943, pi. 3), who also from R. candeiana d'Orbigny in having very presented other observations regarding the biology and coarse perforations, which may prove to be not ecology of the genus Tretomphalus. Myers concluded a specific distinction. (1943, p. 21) that the planktonic stage of Tretomphalus was very brief and lasted usually no more than 18 hours FORAMINIFERA FROM PITS unless the specimen became encrusted with minute Samples were examined from seven pit sections well algae or other organisms, in which case it would remain away from the beach. All the pits were shallow, three afloat indefinitely. If not thus supported, a planktonic in the southern part and four in the central part of the specimen would promptly sink to the bottom after the northern main island. (See USGS Iocs, f 11639-f 11661 .) escape of the gametes through the large pores in the None of the four pits (GOC-4, GOC-5, GOC-6, and spherical float chamber. Thus in a tropical environ­ GOC-17) in the central part of the island exceeded 3 ment where there is no marked seasonal temperature feet in depth. The other three pits (GOC-1, GOC-2, fluctuation and where the water temperature of about and GOC-3) were deeper: about 6 feet, 9 feet, and 11 29° C is well above the 18° C observed to be the mini­ feet, the deepest sample studied from the last hole, mum temperature for development of the floating stages however, being at 10 feet. of Tretomphalus (Myers, 1943, p. 22), a steady supply Omitting the pit at GOC-17, all the excavations of the fragile specimens with float chambers might be started in soil composed of nearly pure Calcarina sand, expected to be constantly added to the bottom much darkened by organic matter, and in which roots sediments. were common. Some, but not all, of the specimens of The Rosalina stages of Tretomphalus, however, pre­ Calcarina were much worn, presumably by abrasion sumably did not live in the bottom sands or muds but before final deposition. The specimens also show the attached to algae or any sort of stemmed structure and effects of corrosion by organic acids in the soil, in that thus could have been obtained by the fish as it browsed. many of the shells are porous with openings into the Nevertheless, most of both forms of this genus were chamber cavities (pi. 25, fig. 7). The dark stain and probably taken in as a part of the bottom sediment porosity of the shells was not observed in material rather than in the process of browsing on algae or coral obtained from below a depth of about 1 foot. (Cloud, 1952, p. 26; 1959, p. 398-399, pis. 130, 131). The uppermost sections of the pits at GOC-1, The trigger and surgeon fishes, most of which contain 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 limesilt throughout, and the entire 2-foot section is in beach sands. (See fig. 41.) These sands are composed sediments transitional between those of a reef-flat of Calcarina with lesser amounts of Amphistegina, horizon and beach sands. No beach sands overlie the Marginopora, and Heterostegina. Minor elements, surface at GOC-17. such as miliolids and species of Bolivina and CymbaJopo- In addition to the pits on the northern main island, retta, increase with depth in pits GOC-3 and GOC-6. a small section is exposed above the beach on the In the lower sections of these pits the orange color of lagoon side of the southern main island at GOC-20. the sand and good preservation of specimens is similar Material in the 3%-foot section is beach sand (pi. 25, to that of modern beach sands, and there is only slight fig. 3), slightly richer and less well worn than that evidence of abrasion. Presumably the species in these occurring in the area of the pits on the northern main pits lived not far from where they were deposited. island. In pits GOC-1, GOC-2, and GOC-4 the beach sands A few of the species found in the pits were not found are gradually transitional into sediments with a much in the lagoon sediments. None of them occur more smaller proportion of Calcarina and a greater variety than very rarely and all are known as Recent species: of other Foraminifera. Nevertheless, even with the Bdelloidina aggregata Carter change, Calcarina remains the predominant element Conicospirillina trochoidea Cushman to the bottom of all the pits. (See pi. 25, figs. 8, 9.) Elphidium milletti (Heron-Alien and Earland) Neoconorbina frustata (Cushman) These richer and more varied sediments are interpreted Patellina advena Cushman as a reef-flat horizon which was built up to become Pegidia dubia (d'Orbigny) progressively shallower and finally to be overrun by Rosalina orientalis (Cushman) the sediments of an adjacent beach sediments that Spiroloculina corrugata Cushman and Todd now overlie it in the pits. The transition between Among the species found rather consistently in the beach sands and reef-flat sediment, however, occurs lagoon and reef sediments, the following are conspicuous at different depths in the various pits. For example, by their absence from the pits: the pit at GOC-3, although sampled to a greater depth Baculogypsina sphaerulata (Parker and Jones) than any other pit, did not even at a depth of 10 Elphidium striato-punctatum (Fichtel and Moll) Hauerina involuta Cushman feet reach the rich fauna of the reef flat horizon (fig. 41). Spiroloculina clara Cushman The pit at GOC-17 was dug through limesand and Valvulina davidiana Chapman

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

fl!644 (11657 f11639 (11650 (11654 ||||fll660 (11651 f 11656 §3 f 11658 f 11645 f11640 (11661 (11655 (11659 (11641 f 11646

f11642

(11648

fl!643 FEET EXPLANATION (11652 1-5 WATER LEVEL

f11649

(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 late comer to this atoll. However Baculogypsina is shallow reef-flat horizon is not the preferred habitat not a late comer in the general area of the western (see occurrence of these species in table 1), and hence Pacific as is evidenced by the fact that at Bikini and their absence is not unexpected. For Baculogypsina Eniwetok atolls it is found in the shallow drillings but sphaerulata, on the other hand, its absence in an is not present in the Recent fauna. environment known to be its preferred habitat is surprising and suggests the existence of some prohibi­ NOTES ON SELECTED SPECIES tive factor, as discussed in the following section. Chrysalidinella dimorpha (Brady)

LOCAL DISTRIBUTION OF CALCARINA AND Plate 22, figure 10 BACULOGYPSINA Chrysalidinella dimorpha (Brady). Cushjnan, 1945, Cushman With but two exceptions, the more abundant species Lab. Foram. Research Contr., v. 21, p. 52, pi. 8, figs. 21, 22. at Onotoa seem to be distributed more or less uni­ formly, though in varying proportions depending upon This species is characterized by its elongate and the facies. The two exceptions are Calcarina spengleri straight-sided form. Only a single specimen was found. (Gmelin) and Baculogypsina sphaerulata (Parker and Elphidium cf. E. poeyanum (d'Orbigny) Jones). Both of these two species are believed to be mainly reef dwellers although some live specimens Plate 23, figure 1 were also found in the bottom sediments adjacent to Rare specimens found in several of the lagoon samples reefs and in some beach sands (f 11676, GOC-38) and are distinctive in having a nearly transparent wall, coarse shallow sediments (f 11677, GOC-45) of the uninflated test, and very short retral processes. In lagoon. these characteristics they are similar to Elphidium Figure 40 shows the 27 localities where either one poeyanum (d'Orbigny) (Cushman, 1939, p. 54, pi. 14, or both of these species was found to constitute a figs. 25, 26), a common species of the West Indian significant part of the Foraminifera population. Sym­ region. They are easily distinguishable from E. simplex bols indicate the approximate relative abundance of Cushman, which has an umbilical plug, a milky wall, these species to each other (not to the total fauna). and a tendency toward inflation of the later chambers. In table 1 it ^ill be observed that either or both are I have not observed this very transparent species present in many other samples, but less abundantly. elsewhere in the western Pacific. It may be seen that in the overall picture Calcarina Globigerina cf. G. inflata d'Orbigny dominates. It is present to the exclusion of Baculogyp­ sina in 11 of the localities. In only 3 localities is Plate 24, figure 1 Baculogypsina present alone, while in the remaining 13 Rare specimens in the lagoon samples, mostly in localities the 2 genera are found together, though those samples from areas open to the ocean on the possibly not living together. Even though live speci­ southwest, seem related to Globigerina inflata d'Orbigny mens were found in the same sample, easy transport (Cushman, 1946, p. 16, pi. 3, fig. 3; pi. 4, figs. 1-4). over short distances by means of surf or currents leaves They are close coiled with four chambers making up the possibility open that the two genera do not occupy the final whorl and have a large, arched and rimmed precisely the same ecological niche. In general the aperture that opens into the umbilicus. samples where Baculogypsina is predominant are from Globigerina inflata was not found in the Globigerina localities in or near breaks in the reef and away from oozes around the Marshall Islands, nor was it observed land areas (pi. 25, figs. 1, 2). among the rare globigerinids found in the shallow sedi­ I have no theories as to the reason for the separate ments around Saipan. Its nearest reported occurrence geographic occurrence, here and elsewhere, of these seems to be the Mid-Pacific seamounts (Hamilton, two genera. I believe it is more than a chance distribu­ 1953, p. 222). tion, and more than a result of incomplete collection of or examination of samples. In each of the seven pits Globigerinita glutinata (Egger) (fl!639-f 11661, GOC-1 to GOC-17) only Calcarina Plate 24, figure 3 was found. As two of these pits (GOC-2 and GOC-3) Globigerinita glulinata (Egger). Phleger, Parker, and Peirson, afford sections of about 9 and 10 feet, respectively, 1953, Swedish Deep-Sea Exped. Repts., v. 7, Sediment the sediments penetrated probably represent deposi­ cores from the North Atlantic Ocean, no. 1, p. 16, pi. 2, tion over a considerable period of time. The fact that figs. 12-15. only Calcarina was found in all the pit samples suggests Rare specimens of this small globigerinid occur in that Baculogypsina may have been a comparatively 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 reef- three of Brady's figures in synonymy, probably by flat horizon from the bottom of one of the pits. oversight, as no mention of P. confusa is made, and the description, figures, and a paratype in the U.S. National Neoconorbina terquemi (Rzehak) Museum collection (USNM 35815) all indicate that a Rosalina orbicularis Terquem, 1876, Essai Classement Animaux form equivalent to Brady's figure 1 (not fig. 3) is meant Plage Environs Dunkerque, Paris, fasc. 2, p. 75, pi. 9, to carry the name of P. bradyi. fig. 4. As comparison of type material of the two species, Rosalina terquemi Rzehak, 1888, Austria Geol. Reichsanst., Verb., p. 228. P. confusa and P. bradyi, indicates possible if not Conorbina orbicularis (Terquem). Parker, 1954, Harvard probable specific differences between the two, the name Coll. Mus. Comp. Zoology Bull., v. Ill, no. 10, p. 522, P. bradyi is retained for the Onotoa specimens. pi. 8, figs. 13, 14. This species is type of the genus Neoconorbina; the Placopsilina? sp. name terquemi was proposed to differentiate Terquem's Plate 22, figures 3, 4; plate 25, figure 5d species from one described earlier under the name by Rare fragments of irregularly curving cylindrical d'Orbigny. agglutinated tubes, consisting of uniserial chambers The species occurs in a few of the lagoon and reef-flat varying in height but usually quite low and uneven in samples, in some samples fairly commonly. Their low, shape, were found in three lagoon samples. One un­ flat, scalelike shape suggests they were attached in broken end shows a smooth, round, and unrimmed life. apertural opening in the depressed center of the final Nubeculina divaricata (Brady) chamber. These fragments may be the upward-growing Nubeculina divaricata (Brady). Cushman, 1932, U.S. Natl. parts of attached specimens of Placopsilina. Mus. Bull. 161, pt. 1, p. 48, pi. 11, figs. 5, 6. This miliolid with arenaceous coating is generally Quinqueloculina polygona d'Orbigny recognizable only when its uncoated tubular neck is Plate 22, figure 5 preserved. It was found in a few of the lagoon and reef Quinqueloculina polygona d'Orbigny, 1839, in De la Sagra, samples. Histoire physique, politique et naturelle de 1'lle de Cuba, Foraminiferes, p. 198, pi. 12, figs. 21-23. Placopsilina bradyi Cushman and McCulloch Cushman, 1932 [part], U.S. Natl. Mus. Bull. 161, pt. 1, Placopsilina bradyi Cushman and McCulloch, 1939, Allan Han­ p. 25, pi. 6, fig. 6 [not fig. 5]. cock Pacific Exped., v. 6, no. 1, p. 112, pi. 12, figs. 14, 15. Typical specimens of this angular miliolid that was Placopsilina cenomana Brady [not d'Orbigny] 1884 [part], described from shore sands of Cuba are present, some­ Challenger Rept., Zoology, v. 9, p. 315, pi. 36, fig. 1 [not figs. 2?, 3]. times abundantly, in the Onotoa samples.

Several specimens of this permanently attached form Rectobolivina? sp. were found on the surfaces of shells and algae from the reef edge (f 11681, GOC-52). They consist of a series Plate 22, figure 8 of coarsely agglutinated chambers, initially coiled, then RectoboUvina sp. Todd, 1957, U.S. Geol. Survey Prof. Paper in a uniserial arrangement and an irregularly winding 280-H, p. 290-291 (table) course. In the Onotoa material, particularly that from the The first mention of this species (see second reference reef-flat horizons in pits GOC-1 and GOC-2, are rare in synonymy) included two and possibly three types of specimens that are questionably referred to this genus. forms under the name Placopsilina cenomana: figure 1, They are identical with some from Tanapag lagoon, coarsely arenaceous, white, and with transverse meas­ Saipan. They are always in association with Sipho- urements of 0.30-0.45 mm; figure 3, arenaceous, orange, generina raphana (Parker and Jones) from which they and with transverse measurements of 0.04-0.08 mm; are distinguishable by their much smaller size (0.35- and figure 2 possibly differing in being either finely 0.55 mm long), slenderer form (0.10-0.20 mm wide), arenaceous or not agglutinated. The distinction be­ more translucent wall, proportionally longer multiserial tween the very small orange one and the larger white stage (becoming biserial but twisted in the present one was recognized by the erection in 1920 of P. confusa material), and the slightly indented sutures and hence Cushman (1920, p. 71, pi. 14, fig. 6) for the former, slightly lobulated outline. They may prove to be leaving the latter in P. cenomana d'Orbigny. The related to Siphogenerina raphana, possibly being in­ original description of P. bradyi, however, included all cluded in the same species. 188 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Rosalina candeiana d'Orbigny and America and from the Eocene (if not older) to the Rosalind candeiana d'Orbigny, 1839, in De la Sagra, Histoire Recent. This compact and close-coiled genus is dis­ physique, politique et naturelle de 1'Ile de Cuba, Forami- tinguished by large pores, particularly on the dorsal niferes, p. 97, pi. 4, figs. 2-4. side, the pores sometimes surrounded by tubular necks, Discorbis opima Cushman, 1933, Cushman Lab. Foram. Re­ and by the aperture being a long, narrow opening ex­ search Contr., v. 9, p. 88, pi. 9, fig. 3. tending from the umbilicus along the base of the This is the commonest of the discorbids found at apertural face to a depression beneath the periphery Onotoa, occurring in nearly all the lagoon samples and where it widens and extends upward into the apertural on the reef flats. It is too fragile to persist in the beach face. sands. As is typical of the family Discorbidae, speci­ The first reference cited above is to specimens of this mens were probably loosely attached by their ventral genus from Recent lagoon sediments of Saipan; the surfaces during life, but not cemented, so that as second to specimens from the upper part of the Eniwe- empty tests they were easily washed down into the tok drill holes in the Marshall Islands. Identical speci­ bottom sediments. mens are found rarely at Onotoa. They seem very close to the type of the genus, Discorbis tuberculata Rosalina concinna (Brady) (Balkwill and Wright) var. australiensis Chapman, Discorbina concinna Brady, 1884, Challenger Kept., Zoology, v 9, Parr, and Collins, but may prove to be distinct when p. 646, pi. 90, figs. 7, 8. sufficient material becomes available. Discorbis micens Cushman, 1933, Cushman Lab. Foram. Re­ search Contr., v. 9, p. 89, pi. 9, fig. 5. REFERENCES CITED This small circular scalelike species was also attached Cloud, P. E., Jr., 1952, Preliminary report on geology and marine during life. It is almost surely the early stage of the environments of Onotoa Atoll, Gilbert Islands: Natl. Acad. species of Tretomphalus that is called T. concinnus ScL, Natl. Research Council, Pacific Sci. Board, Atoll Re­ (Brady), referring to the same Brady reference as above. search Bull. 12, p. 1-73, figs. 1-8. Thus the separation of these two forms is wholly 1959, Geology of Saipan, Mariana Islands. Part 4, Submarine topography and shoal-water ecology: U.S. Geol. artificial and a matter of convenience. In most samples Survey Prof. Paper 280-K, p. 361-445, pis. 2, 120-139, where either is common, the two forms occur together. figs. 36-43. Cushman, J. A., 1920, The Foraminifera of the Atlantic Ocean. Rosalina orientalis (Cushman) Part 2, Lituolidae: U.S. Natl. Mus. Bull. 104, pt. 2, p. 1- Discorbis orientalis Cushman, 1926, B. P. Bishop Mus. Bull. 27, 111, pis. 1-18. p. 130 [imprint date 1925]. 1939, A monograph of the foraminiferal family Non- Todd, 1957, U.S. Geol. Survey Prof. Paper 280-H, p. 290- ionidae: U.S. Geol. Survey Prof. Paper 191, p. 1-100, pis. 291 (table), pi. 90, fig. 13. 1-20. 1946, The species of Globigerina described between 1839 Comparison with the types indicates that this species and 1850: Cushman Lab. Foram. Research Contr., v. 22, is merely a high-spired form of Rosalina candeiana. p. 15-21, pis. 3, 4. Cushman, J. A., Todd, Ruth, and Post, R. J., 1954, Recent Spiroloculina rugosa Cushman and Todd Foraminifera of the Marshall Islands: U.S. Geol. Survey Spiroloculina rugosa Cushman and Todd, 1944, Cushman Lab. Prof. Paper 260-H, p. 319-384, pis. 82-93, figs 116-118. Foram. Research Spec. Pub. 11, p. 66, pi. 9, figs. 9-13. Hamilton, E. L., 1953, Upper Cretaceous, Tertiary, and Recent planktonic Foraminifera from Mid-Pacific flat-topped sea- A single specimen of this species with its distinctively mounts: Jour. Paleontology, v. 27, p. 204-237, pis. 29-32, rugose wall was observed in f 11667, GOC-29. figs. 1-5. Myers, E. H., 1943, Biology, ecology, and morphogenesis of a Spiroloculina venusta Cushman and Todd pelagic foraminifer: Stanford Univ. Pubs., Biol. Sci., v. 9, Spiroloculina venusta Cushman and Todd, 1944, Cushman Lab. no. 1, p. 1-30, pis. 1-4. Foram. Research Spec. Pub. 11, p. 60, pi. 8, figs. 16, 17. Pokorny, Vladimir, 1956, New Discorbidae (Foraminifera) from the upper Eocene brown Pouzdfany marl, Czechoslovakia: This species was found rarely in the lagoon samples. Prague, Univ. Carolina, Geologica, v. 2, no. 3, p. 257-278, figs. 1-15. Svratkina sp. Todd, Ruth, 1957, Smaller Foraminifera, in Geology of Saipan, Epistominella sp. D, Todd, 1957, U.S. Geol. Survey Prof. Paper Mariana Islands. Part 3, Paleontology: U.S. Geol. Survey 280-H, p. 292-293 (table), pi. 92, fig. 2. Prof. Paper 280-H, p. 265-320, pis. 2, 4, 64-93, tables 1-4. Svratkina sp. A, Todd and Low, 1960, U.S. Geol. Survey Prof. Todd, Ruth, and Low, Doris, 1960, Smaller Foraminifera from Paper 260-X, p. 840. Eniwetok drill holes: U.S. Geol. Survey Prof. Paper 260-X, p. 799-861, pis. 255-264, text figs. 256-259, tables 1-7. The genus Svratkina was erected (Pokorny, 1956, p. Walton, W. R., 1952, Techniques for recognition of living Foram­ 257) for specimens that had been previously reported inifera: Cushman Found. Foram. Research Contr., v. 3, under various other names from Australia, Europe, pt. 2, p. 56-60. INDEX [Italic numbers indicate descriptions] A Page Page Page Abanekeneke..______-__ 176 bradyi, Cymbaloporetta...... 176,179,181,182,183 dispar, Elphidium advenum...... _... 176,179,183 Acanthurus gahhm...... --...... _ 182,183 Parrina .______178,183 distcrqueata, Quinqueloculina ...... 177 acervalis, Planorbulina..... ______176,180,183 Placopsilina...... 178,187 Distribution of Calcarina and Baculogypsina, Acervulina...... 182,184 Buariki Maneaba--_____._____-.... 174 local ------.----.-_.....__-._.__., 186 inhaerens-...... ____ 176,180,183 Ruliminella milletti...... 178 Distribution of Recent Foraminifera.___ 177-180 sp ..._ 180 Buliminidae.------..-----.---...-.-...-.-. 178,183 divaricata, Nubeculina...... 178,187 acicularis, Spirolina__- ....__.__.... 178 JRuliminoides williamsonianus...... -.-.-.. 178,182 diversa, Hauerina...... 178 Acknowledgments.___...______.__ 171 bulloides, Globigerina__....___.--__-. 180 dubia, Pegidia...... 179,185 aculeatus, Rhinecanthus______182,183 buniva, Melichthys. -...... ______182,183 dupla, Textularia...... 177,182 advena altiformis, Patellina...... 179 Patellina--- ...... 179,185 C E advenum dispar, Elphidium...... 176,179,183 Calcarina...... 172,173,174,184,185,186; pi. 25 earlandi, Triloculina-______177 Elphidium...... __._-...______179 hispida.-...... 181 echinatus, Siphoninoides-...... 179,182 aequilateralis, Olobigerinella...... _____ 180 spengleri...... 176,179,181,183,186; pi. 25 eggeri, Olobigerina-...... 180;pl.24 apglutinans, Quinqueloculina...... 177 Calcarlnidae. -- - -. 179,183 ellipticus, Peneroplis______178,182,183 Textularia...... 177 Camerinidae---...... 178,183 elongata, Articulina-....-.-.-...... 178 aggregata, Bdelloidina...... 178,185 candeiana, Rosalina...... 176,179,183,184, 188 Elphidiidae-.. . - - 179,183 Aiaki Maneaba... . 174,175,176; pi. 25 Textularia...... 177,183 Elphidium...... 182 AUiatina translucens.--.....-...... 179; pi. 23 Cantherines sandwichensis...... ------182,183 odvenum...... 179 altiformis, Patellina advena-...... 179 Cardium---...... 174 dispar...... 176,179,183 alveola, Textularia------...... ___ 177 Cassidulina minuta...... 179,182 crispum.. ____ 176,179,183 Alveollnellidae.------_ 178 Cassidulinidae -- 179 miaetti 179,185 alveoliniformis, Ammomassilina-...... __ 178 poeyanum...... 179,186;pl.23 Schlumbcrgerina...... 176,178,181,182,183 cenomana, Placopsilina...... 187 Chrysalidinella dimorpha...... 179, 186; pi. 22 simplex...... -...-..... 179,183,186 A mmobaculitessp ------...... 177; pi. 22 striato-punctatum...... 176, A mmomassilina alveoliniformis______178 Cibicidella...... 184 variabilis - ...... 176,180,183 179,181, 182,183,185; pi. 25 ammonoides, Operculina ...... 181 Eniwetok atoll, Marshall Islands.- 181,186,188 Amphistegina ...... 182,185; pi. 25 Cibicides -- -- 184 cicatricosus..-...... 180 Epistomaroides polystomelloides...-...... 179, 182 madayascoriensis.---. 176,179,181,182,183; pi. 25 Epistominella tubulifera ---- 179,182 Amphisteginidae-______-______179,183 lobatulus... . - 180,183 mayori-.-...... ------180 sp.. 188 anguina arenata, Quinqueloculina...... 177 Examination offish contents...... 182-184 angularis, Clavulina----...... 177,183,184 pseudoungerianus------....------180 cicotric"sus, Cibicides...... - 180 exigua, Planispirinella...... 178 angulata, Spiroloculina---...... 176,177,183 eximia, Spiroloculina-...... 177 Anomalina glabrata...... 180 clara lirata, Spiroloculina---...... - 177 Spiroloculina...... IT!, 182,183,185 Anomalintlla rostrata...... 181 F Anomalinldae------___...... 180,182,183 Clavulina angularis...... 177,183,184 Aon teBaba.. --- -. 174,175; pi. 25 multicamerata...... _____.- 183,184 Fauna 176-181 Aontebeke land area.-.______.___. 176 communis, Spiroloculina...... - 177 ferussaci, Quinqueloculina...... 177 Aon te Rabata shoals... .-.______- 174,175 compacta, Bolivina...... ------179 Fischerina pellucida.... 178; pi. 22 arenata, Quinqueloculina anguina...... 177 concinna, Discarbina...... 188 Fischerinidae.-___ 178 arietini, Spirolina-- ______176,178,181,183 Rosalind 179,183,188 Fissurina lacunata. 178 Arothron nigropunctatus...... ____..._ 182,183 concinnus, Tretomphalus..... 176,179,183,188; pi. 24 lagenoides___.__ -- 178 Articulina elongata.-...... 178 confusa, Placopsilina- _____------187 milletti-... 178 pacifica______178 conglobatus, Globiqerinoides-...... 180 foliacea oceanica, Textularia...... 177,181,182 auriculata, Wiesnerella...... 178 Conicospirillina trochoidea-...... 179,185 Textularid 177,181,182 australiensis, Discorbis tuberculata...... 188 sp.--- 179,183; pi. 23 folium, Bolivinella...... - 178,181 australis, Miliolinella...... __ 178,183 Conorbina orbicularis-.-...... 187 frondescens, Sagenina...... 177 Corvuspira planorbis--...... 176,178,183 frustata, Neoconorbina..--...... ------179,185 B corrugata, Spiroloculina...... 177,185 cribrorepandus, Poroeponides...... 179,182,183 G Baculogypsina...... 172,174,175,184,186; pi. 25 crispum, Elphidium...... 176,179,183 Ctenochaetus cyanoguttatus...... 182,183 gahhm, Acanthurus.. 182,183 sphaerulata...... 176,179,181,183,185,186; pi. 25 Oaudryina pauperata.-. - 177,183 gtriatus. 182,183 Balistapus undulatus...... 182,183 (Siphogaudryina)...... --. .. 182 cuneata, Triloculina-...... 177,183 Bdtlloidina aggregata-...... 178,185 rugulosa-..-. - 176,177; pi. 25 cyanoguttotus, Ctenochaetus...... 182,183 Beach sands...... 171,176,185,186; pi. 25 siphonifera...... - 177 Cymbaloporetta...... 184,185 beccarii, Streblus...... 179,181,182,183 glabrata, Anomalina...... ------...... 180 bradyi...... 176,179,181,182,183 tepida, Streblus...... ______179 Globigerina bulloides...... -.------180 berthelotiana, Quinqueloculina--..... ____ 177 squammosa...... 176,179,181,182,183 Cymbaloporidae.--.... _ .... 179,182,183 eggeri...... 180; pi. 24 bicarinata, Triloculina----...... 177 inflate . 180, 186; pi. 24 bidentata, Quinqueloculina--- _____ 177,183; pi. 22 D Glcbigerinella aequilateralis------180 Bikini atoll, Marshall Islands----.-....__ 181,186 dovidiana, Valvulina...... 177,182,185 Globig' rinida»-._...... 180,183 Bolivina...... 182,185 decorata, Spirillina-...... 179 Globigerinita glutinata. 180, 186; pi. 24 compacta...... _.... 179 denticulata, Pyrgo.- _____.__------. 178 Globigerinoides conglobatus...... ------180 (Loxostomum) limbota....._...... 179 denticulo-granulata, Spirillina..... -- - 179; pi. 23 ruber- 180,183 mayori---...... 179 dimorpha, Chrysalidinetta...... 179, 186; pi. 22 sacculifer...... 180,183 rhomboidalis.. ______179 Discorbidae---.------179,183,188 globula, Oypsina...... ------I80 striatula...... 179,183 Discorbina concinna.-...... 188 glutinata, Globigerinita.- - 180, 186; pi. 24 subexcavata...... 179 Discorbis micens...... ____------188 Government Station... 173,174,175,176; pi. 25 tortuosa.-...... 179 opima...... 188 Gypsina globula-- .....------1^ Bolivintlla folium...... 178,181 orientolis - 188 plana...... - - --- I80 Borelis pulchrus.. ___.______178 tuberculata australien sis...... 188 vesicularis. ... 180 189 190 INDEX

H Page Page Quinqueloculina Continued Page Haddonia torresiensis...... 176,178,182 neostriatula, Quinqueloculina-...... 177,183 distorgueata ...... 177 Halimeda...... 174 nigropunctatus,Arothron...... 182 ferussaci...... 177 Hauerina diversa..... ______. 178 Nonion pacificum...... 179 neostriatula-....-.-...... 177, 183 involuta ...... 178,183,185 Nonionella sp______179 polygona...... 176, 177, 187; pi. 22 milletti- ...... 178,183 Nonionidae -______179 sulcata...... 177, 183 pacified...... -.....------__-_-. 178,183 Notes on selected species-.-..-______-. 186-188 tubus ...... -...-.. ..-. 177 serrata______178 Nubeculmadivaricata...... 178,757 R speciosa ...... 178 Rakai Ati reef. - 175 Heliopora ...... 173,174 O Maneku. __ 175 Heterohelicidae..______178 obliguiloculata, Pulleniatina...------.180; pi. 24 ni Make 175 Heterostegina------...... 184,185; pi. 25 oblonsa, Triloculina ...... 176,177,183 raphana, Siphogenerina...... 176,179,183,187 suborbicularis--...... n6, 178,181,183,184; pi. 25 octanica, Miliolinella ---.-...... 178 Rawa ni Karoro -- 174 hispida, Calcarina...... 181 Textulariafoliacea- ...... 177,181,182 rectangulus, Rhinecanthus- ...... 182,183 Homotrema ...... 182,184 Operculina ammonoides-...... 181 Rectobolivina sp~. 179, 183, 187; pi. 22 rubrum...... 176,180,182,183 Ophthalmidlidae-.-...... 178,183 Reef areas 171, 176, 177-180, 181, 184, 185 Homotremidae.______180,183 opima, Discorbis...... 188 References cited 188 Hyperamminidae--______177 orbicularis, Conorbina...... ______-__ 187 retinaculatus, Planorbulinoides...... 180,182,183 I Rosalina--...... 187 Reussella simpl'x...... 176, 179, 182, 183 inaeaualis, Spirillina- ______. 179 Orbulinauniversa...... 180; pi. 24 revertens, Spirillina vivipara ...... 179 incisura, Triloculina...... 177,183 orientalis, Discorbis...... 188 Rhinecanthus aculeatus. _ .- ___ .- 182, 183 inflata, Globigerina-...... 180, 186; pi. 24 Rosalina...... 179,185, 188 rectangulus...... 182,183 inhaerens, Acervulina______176,180,183 Otoae village Maneaba_...__---_- 174; pi. 25 rhomboidalis, Bolivina-- ...... 179 Introduction___.- . ...____ 171 Robertinidae -- - - - 179 involuta, Hauerina...... 178,183,185 Rongelap atoll, Marshall Islands- -. 181 irregularis, Triloculina...... 176,177,183 Pacific Science Board campsite____ 173; pi. 25 Rongerik atoll, Marshall Islands ------181 Islands along east side______171,176,177-180 pacifica, Articulina--... ___-_____-- 178 Rosalina 182, 184 Hauerina...... 178,183 candeiana 176, 179, 183, 184, 188 K pacificum, Nonion...... 179 condnna . - - 179, 183, 188 kerimbatica, Triloculina...... _____ 177,183 popifata, Sphatridia.-...... 179 orbicularis...- ...... 187 L Parrina bradyi...... 178,183 orientalis . . 179, 185, 188 labiosa, Miliolinella...... 178,183 patelliformis, Neocmorbina...... 176,179,183 rugosa 183, 184 lacunata, Fissurina... ______178 Patellino advene...... 179,185 ------187 lagenoides, Fissurina.....------...... 178 advena attiformis...... __.--- 179 rostrata, Anomalinella- - 181 Lagoon._...... 171,176,177-180,181,182,184 pauperota, Gaudryina...... 177,183 Rotaliidae 179, 183 Leeward side---.------...------171,176,177-180 Pegidiadubia...... 179,185 rotundatus, Pyropilus ...... 176, 179, 182; pi. 22 limbata, Bolivina (Loxostomum)...... 179 Pegidiidae ...... 179 ruber, Globigerinoides ...... 180,183 lirata, Spiroloculina clara...... 177 ptllucida, Fischerina...... 178, pi. 22 rubra, Planorbulina...... 180 Lituolidae ...... 177 Peneroplidae. - 178,183 rubrum, Homotrema...... 176, 180, 182, 183 lobata, Forties______..__ 174 Peneroplis ellipticus...... 178,182,183 rugosa, Rosalina- ...... - ---- 183,184 lobatulus, Cibiddes...... 180,183 proteus...... 178,183; pi. 22 Spiroloculina-.---. . 177,188 Locality data______173-176 Pitts, Foraminifera from ______171, (Loxostomum) limbata, Bolivina...... 179 176, 177-180, 184-186; pi. 25 rugulosa, Gaudryina (Siphogaudryina). 176, 177; pi. 25 mayori, Bolh'ino...... 179 Placopsilina...... 187 M bradyi...... 178,187 cenomcna______.. 187 sacculifer, Globigerinoides.. ----- 180,183 madagascariensis, Amphistegina...... 176, confuso...... ______--.- . 187 Sagenina frondescens...... - 177 179,181,182,183; pi. 25 sp . 178, 182, 187, pis. 24 25 Saipan Island-... 181,186,187,188 Mangaia land area____._---_____-. 176 Placopsilinidae______178 sandwichensis, Cantherines...... 182,183 marginalis, Sorites...... 178,182 plona, Gypsina...... 180 Scan/a sp__-- 182,183 Marginopora . . 173,174,175,184,185; pi. 25 planota, Massilina--...... --.. 177 ScHumbergerina alveoliniformis- 176,178,181,182,183 vertebralis ...... 176,178,181,183,184 Plonispirinella exigua...... -...... 178 serrata, Hauerina...... ------178 Mariana Islands______----____ 181 planorbis, Cornuspira...... 176,178,183 Sigmomorphina terguemiana 178 Marshall Islands.--__...... 181,186,188 Planorbulina...... 182,184 simplex, Elphidium...... - 179,183,186 marshallana, Triloculina...... 177 acervalis-...... 176,180,183 Reussella------176,179,182,183 Massilina planata...... 177 rubra-...... 180 (Siphogaudryina), Gaudryina...... 182 Material studied...______171 Planorbullnldae... 180,182,183 rugvlosa, Gaudryina...... 176,177; pi.25 mayori, Bolivina (Loxostomum)...... 179 Planorbulin aides...... ------184 siphonifera, Gaudryina...... 177 Cibiddes...... 180 retinaculatus - ...... 180,182,183 Siphogenerina raphana. .. 176,179,183,187 Melichthys buniva...... 182,183 planus, Tretomphalus-...... 176,179,183; pi. 24 siphonifera, Gaudryina (Siphogaudryina)-... 177 micens, Discorbis- ...... ______188 poeyanum, Elphidium-...... 179,186; pi. 23 Siphonina tubulosa 179 Mid-Paciflc seamounts..______186 politum, Monalysidium. ___------178 Sipl-oninoides echinatus...... 179,182 Miliolidae ...... 177,178,183 polygona, Quingueloculina ... 176,177,187; pi. 22 Sorites marginalis...... ------178,182 Miliolivella australis...... 178,183 Polymorphinidae..__--.-_------178 Southern part of atoll 171,177-180 labiosa...... 178,183 polystomellcides, Epistomaroides...... 179,182 speciosa, Hauerina...... ------178 oceanica...... ___.. 178 Porites lobata...... --.-- - 174 spenf/leri, Calcarina.- 176,179,181,183,186; pi. 25 milletti, Buliminella______..____ 178 Poroeponides cribrorepandus.- ...... - 179,182,183 Sphaeridia papillata.- . ------179 Elphidium...... 179,185 porrtcta, Uvigerina___-__ - 179 sphaerulata, Baculogypsina 176, 179, 181, 183, 185, Fissurina--...... 178 proteus, Pentroplis...... 178,183; pi. 22 186; pi. 25 Hauerina...... 178,183 pseudoungerianus, Cibiddes...... 180 spinata, Triloculina- 177 minuta, Cassidulina.-..-...... 179,182 pulchrus, Borelis--...... 178 Spirillina.------.. - 182 Monalysidium politum_...... 178 Pullenfttinaobliquiloculata ...... 180; pi. 24 decorata- .. . - -- 179 multicamerata, Clavvlina--...... 183,184 Pyrgo dentkulata... _____ 178 denticulo-granulata...... -..-- 179, pi. 23 N Pyropilus rotundatus 176,179,182; pi. 22 inaeaualis.-.-...... 179 Nanntabuariki islet...______174; pi. 25 tuberculato-limbata...... -... .. - 179 N"eoconorbina...... ______.. 182,184,187 vivipara.. - 179,183 frustata...... 179,185 Quinqueloculina agglutinans_ - --- 177 revertens--- 179 patflliformis...... 176,179,183 anguina arenata. __------177 SpiriUinidae 179,183 terguemi...... 179, 187 berthelotiana___ 177 Spirolina adcularis..-.. -.. - 178 tuberocapitata______.___. 179 bidentata-...... -. - 177,183; pi. 22 arietina ...... 176,178,181,183 INDEX 191

Page Page Triloculina Continued Page Spiroloculina angulata. . _. ______176.177,183 terquemi, Neoconorbina..... ------._-.-.---_ 179, 187 terguemiana...... 183,184 cZara__ ---_------177,182,183,185 Rosalina... ______-____..__ 187 transversestriata... ______177 lirata...... ------177 terguemiana, Sigmomorphina...... 178 tricarinata...... ______. 177 communis...... -__------177 Triloculina...... 183,184 trigonula...... 177,183 corrugata.-.-..... ___--- --_----- 177,185 Textularia agglutmans...... 177 trochiidea, Conicospirillina...... 179,185 ezimia...... ------177 alveata...... 177 tuberculata australiensis, Discorbis...... 188 rugosa...... -___---____-.-_-__ 177, 188 candeiana...... 177,183 tuberculato-limbata, Spirillina...... 179 venusta.-... ------177, 188 dupla...... 177,182 tuberocapitata, Neoconorbina...... ______179 sguammosa, Cymbaloporetta..... 176.179,181,182,183 foliacea...... 177,181,182 tubulifera, Epistominella...... 179,182 Streblus beccarii._____._____ 179,181,182,183 oceanica...... IT!, 181,182 tubulosa, Siphmina...... 179 beccarii tepida...... 179 Textulariidae ------. 177,183 tubus, Quinqueloculina___....______177 striato-punctatum, Elphidium.... 176, 179, 181, 182, Thalassla...... 175 U 183,185, pi. 25 torresie nsis, Haddonia...... 176,178,182 undulatus, Balistapus...... 182,183 striatula, Bolivina...... 179,183 tortuosa, Bolivina...... ------___ 179 unirersa, Orbulina...... 180; pi. 24 striatus, Ctenochaetus...... -_._____ 182,183 transitions, Alliatina...... 179;pi. 23 Uvigerinaporrecta...... ___--. 179 subexcavata, Boliiiina...... 179 transversestriata, Triloculina...... 177 suborbicularis, Heterostegina.... 176,178,181,183, 184; Tretomphalus...... 182,184,188 V pi. 25 concinnus...... 176,179,183,188; pi. 24 Valvulina davidiana...... 177,182,185 subplanciana, Triloculina...... _____ 177,183 planus...... 176,179,183; pi. 24 Valvulinidae-...... 177,183 sulcata, Quinqueloculina.-----...... 177,183 variabilis, Cibicidella...... 176,180,183 tricarinata, Triloculina...... 177 Svratkinasp...... 179,183,^55 venusta, Spiroloculina...... 177,188 trigonula, Triloculina...... 177,183 Verneuilinidae- - .-_-_..__-.-_ 177,183 T Triloculina bicarinata...-.....-...... 177 vertebralis, Marginopora...... 176,178,181,183,184 Tabuarorae islet------__-____-__ 176; pi. 25 cuneata...... 177,183 vesicularis, Gypsina...... ______-- 180 Maneaba.______175,176 earlandi..... -_.-__-______-- 177 visipara revertens, Spirillina...... 179 Taneang-Tekawa Maneaba-----__.__ 174, pi. 25 incisura...... 177,183 Spirillina...... 179,183 Tebaki 175, 176 irregularis...... 176,177,183 Tekawa-.-.-----.------. 175 kerimbatica...... _____-. 177,183 W church-.. __- -- _-_ 174,175;pi. 25 marshallana...... 177 Wet samples------_------181-182 tepida, Streblus beccarii...... 179 oblonga...... 176,177,183 Wiesnerella auriculata...... ___ 178 Te Rawa ni Bao . 175 spinata...--.-...... 177 williamsonianus, Buliminoides...... 178,182 Te Rawa Tekatoblbi.----... ____ _ 175 subplanciana...... 177,183 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. Well- worn 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), Placop- silina? 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

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FORAMINIFERA SANDS FROM ONOTOA ATOLL