Eocene Mollusks 

From Eua, Tonga

GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C
Eocene Mollusks 

From Eua, Tonga

By HARRY S. LADD

LATE EOCENE FOSSILS FROM EUA, TONGA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C

Twenty-Jive mollusks are described 

from off reef tuffaceous limestone

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

Library of Congress catalog-card No. 77 608174

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

Washington, D.C. 20402 - Price 55 cents (paper cover)
LATE EOCENE FOSSILS FROM EUA, TONGA FOREWORD

One of the most widespread units of the Cenozoic 

section in the islands of the open Pacific is a series of 

limestones assigned to the upper Eocene (Tertiary 6). 

Such limestones, containing diagnostic larger Foraminifera, have been reported in many parts of an area 

spreading 4,000 miles across the tropical Pacific (fig. 1), 

from Palau and the Mariana Islands on the northwest 

through the Marshall Islands (Eniwetok) to Fiji and 

Tonga on the southeast (Whipple, in Hoffmeister, 1932, 

p. 79-86; Asano, 1939; Cole, 1950, 1957a, 1957b, 1960). 

In almost all the islands the limestones are dense and 

crystalline. Foraminifera and algae are abundant locally, but in most places fossils cannot be extracted and 

must therefore be studied in random thin sections. On 

the little island of Eua, Tonga, a locality was recently 

found where the Eocene limestone is tuffaceous, considerably weathered, and richly fossiliferous. Abundant 

fossils that represent a dozen organic groups were found. 

Such abundance and diversity signaled the find as a 

remarkable one that would add greatly to our knowledge of life in the western Pacific during the Eocene.

The island of Eua measures only 12 by 5 miles but 

it rises 1,000 feet above sea level. It occupies an interesting position tectonically, as its steep eastern side 

faces the Tonga Trench. In addition, Eua is the oldest 

island in the Tonga group that has a plutonic core 

(Guest, 1959) and a series of associated volcanic rocks, 

which are partly blanketed by thick limestones of late 

Eocene age. Younger volcanic rocks and sediments of 

late Tertiary age are also present (Hoffmeister, 1932).

This series of reports is concerned with one facies of 

the upper Eocene limestone. After the limestone series 

was deposited, Eua was uplifted periodically and a 

sequence of six terraces was cut in the limestones on 

the windward (eastern) side. Hoffmeister was the 

first to recognize the Eocene age of the main limestone 

of the terraces, three of which have veneers of Pliocene 

reef corals. He made a planetable map of the terraced 

eastern ridge and recorded the average altitudes of the 

terraces as 100, 200, 340, 400, 550, and 760 feet. The 

east-facing "rocky backbone" of Eua thus looks in 

profile like a giant staircase facing the Tonga Trench. 

The Eocene limestone may once have covered all of Eua

but is now largely limited to the eastern ridge (Hoffmeister, 1932; the Eocene Foraminifera were described by Whipple in this same report, p. 79-86).

The fossils described in this series of reports were 

obtained from an outcrop on the 400-foot terrace 

about a quarter of a mile north of Vaingana (fig. 2). 

At this locality, the limestone lies close to the underlying volcanic rock and is tuffaceous and partly 

weathered; almost everywhere else on Eua the limestone 

is pure, hard, and crystalline.

In 1943, Harold T. Stearns, then of the U.S. Geological Survey, also served as a consultant to the 

Armed Forces at Pacific bases and made a brief 

visit to Eua. He collected a sample that contained 

half a dozen fossil brachiopods from the 400-foot 

terrace on the eastern side of the island. Stearns recorded the locality as: "Tele-a-hiva at elevation 

of 400 feet about % mile north of army lookout tower, 

at the second stream north of Vaigana [sic]." The 

brachiopods were examined by G. A. Cooper of the 

U.S. National Museum. Some years later when I 

was studying other island fossils collected by Stearns, 

Cooper showed me the brachiopods and expressed 

a desire for additional specimens so that he could 

continue his study of their internal structures.

In 1966,1 learned that Yoshio Kondo of the Ber^ice 

P. Bishop Museum in Honolulu intended to visit Eua in 

connection with his studies of living Pacific island land 

snails (under National Science Foundation grant 

GB-3974). I sent Stearns' locality data and marked 

copy of Hoffmeister's Eua map to Kondo, and I informed Stearns of the plan to collect additional 

material.

Late in August 1967, Kondo reached Eua and, aided 

by a Tongan guide, Tomiki, and an interpreter, Mo^ese 

Vea, spent 2 days searching for the fossil locality. The 

lookout tower mentioned by Stearns no longer exists 

and Kondo found that Tele-a-hiva translates to "Fine 

Gulches." Traveling northward from "Vaigana" (Otu 

Vaingana) through heavy brush on exceedingly rugged 

karst topography for about 1,000 feet, he reached the 

first of the gulches. There he found a soft fossilife^ous 

layer between two harder limestones and collected a

in
40-pound sample of the material. This gulch locality 

is probably not the exact spot visited by Stearns. The 

two collections have minor differences in nature of preservation, but they obviously came from the same formation.

The exact extent of the richly fossiliferous bed is

not known but it is probably limited both horizontally 

and vertically. In 1926, when Hoffmeister made his 

map of the terraces, he did not come upon this facies, 

and in 1928 when I spent 2 weeks on Eua with Hoffmeister, reviewing his mapping, no exposures of this 

zone were seen although we visited Vaingana. AddiFIGURE 1. Location of Tonga and other island groups in the southwest Pacific where upper Eocene limestone has been identified. 

Dashed line marks structural boundary of the Pacific Basin (andesite line). Islands shown include the surrounding reefs.

IV
FIGURE 2. Map of Eua, Tonga, showing the location of the 

recently discovered fossil outcrop (X) and the main mass 

of Eocene limestone (patterned area) on the east side of 

the island, as mapped by Hoffmeister (1932).

tional fieldwork in the area of the rugged "Nine 

Gulches" would be worthwhile.

William Melson of the Smithsonian Institution examined hand specimens and thin sections of the tuffaceous limestone and noted that the volcanic constituents are highly altered, making it difficult to determine 

their original nature. The rock is composed of 50 

percent or more of volcanoclastic debris, much of which 

has been replaced by calcite. The predominant volcanic fragments are of porphyritic pumiceous glassy 

material; most of the phenocrysts are plagioclase, now 

largely replaced by calcite. The original groundmass 

of pumiceous glass is now devitrified and dark brown. 

Fragments of tuff are rare. There appears to be a 

large and varied assemblage of secondary minerals. 

The volcanic fragments are mainly porphyritic andesitic rocks, or possibly plagioclase-bearing dacites. The 

presence of abundant fossils suggests that the volcanic 

material has been reworked.

The soft tuffaceous limestone collected by Kondo 

was treated with a wetting agent and penetrant in the 

laboratory. The material broke down easily, revealing 

a variety of fossil remains: Foraminifera, discoasters, 

corals, hydrozoans, brachiopods, bryozoans, annelids, 

crinoids, echinoids, ostracodes, barnacles, decapod crustaceans, mollusks, shark teeth, otoliths, and spores and 

other plant microfossils.

W. Storrs Cole has described the larger Foraminifera; these fossils suggest to him a depth of deposit on 

of about 200 feet, but other groups notably the 

smaller Foraminifera, the corals, brachiopods, bryozoans, mollusks, ostracodes, and barnacles point to 

a considerably greater depth of deposition.

Material representing a total of 17 organic groups 

was distributed to paleontologists for study and report. 

Seven of these collections were small or were made up 

of incomplete specimens leading only to summary 

reports, but the others, except for the larger Foraminifera, contained much new material. The brachiopod, 

bryozoan, ostracode, barnacle, and mollusk collections 

contained the first identifiable Eocene species from the 

islands of the open Pacific, an area extending 4,000 

miles from Palau to Tonga.

HARRY S. LADD

CONTENTS

Foreword. ... . ____

Abstract. ____ ___ _ _ . - _-__-____

Introduction ______________

Acknowledgments __ _- _ ___

Age and conditions of deposition _ ___

Systematic paleontology __ _ _ ____

ScissUrellidae _ _ _ _ . _ _ __.

Trochidae __ _ _ .. ___ _

Turbinidae _ _ _ _ _ _.

Mathildidae-- __________

Page

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_-._-.__._ 1

1

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-________. 2

._____._._ 3

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K.

........ . 6

6

6

I Systematic paleontology Continued 

Xenophoridae __ _____ .__

Ovulidae ___ _ ___________ ____ _ _ _ _ _

Atyidae

Ostreidae _________ _ _ - _._

Corbulidae___ _____ _ ___ _ ___ ___

References cited_ __ ____________

Tndfix

C7

7

7

7

9

9

11

ILLUSTRATIONS

[Plates 1-5 follow index]

PLATE 1. Rock samples showing abundance, diversity, and size range of fossils.

2. Scissurellidae and Trochidae.

3. Trochidae, Turbinidae, Adeorbidae, Xenophoridae.

4. Adeorbidae, Mathildidae, Cerithiopsidae, Epitoniidae, Ovulidae, 

Naticidae.

5. Fasciolariidae, Conidae, Terebridae, Pectinidae, Ostreidae, Corbulidae.

FIGURE 1. Map showing the location of Tonga and other island groups in the southwest Pacific where upper Eocene limestone has been identified- _____ 

2. Map of Eua, Tonga, showing the location of the recently discovered fossil 

outcrop and the main mass of Eocene limestone._________________

Page

TABLES

Page

TABLE; 1. Geologic range of genera and subgenera of mollusks from Eua, Tonga. __ C2 

2. Distribution and depths of living relatives of new Eocene species from

Eua, Tonga__________________________________________________ 2

VII

LATE EOCENE FOSSILS FROM EUA, TONGA

EOCENE MOLLUSKS FROM EUA, TONGA

By HARRY S. LADD

ABSTRACT

Twenty-five mollusks have been recovered from tuffaceous 

limestones of late Eocene age; 22 are gastropods, three are 

pelecypods. Nine species, all gastropods, are described as new. 

The assemblage suggests a depth of water of about 100 fathoms. 

A few shells suggest shallow water, but most of these are worn 

and probably have been carried in.

INTRODUCTION

The geographic and stratigraphic position of the 

fossiliferous beds and the circumstances leading to the 

collection of the material are discussed under the heading "Foreword." The rock is a tuffaceous limestone containing abundant fossils that represent many organic 

groups (pi. 1).

Eocene mollusks are known to occur in the crystalline 

limestones of Palau, the Mariana Islands (Cloud and 

others, 1956, p. 50), and the Marshall Islands (Ladd and 

Schlanger, 1960, p. 894-895). Several fossil mollusks 

from the limestones of Makatea in the Tuamotu Archipelago are said to have an Eocene aspect but they have 

not been fully described (Eepelin, 1919). Some of the 

Marshall Island shells have been identified, but descriptions have not yet been published. No closely comparable Eocene deposits have been described from 

Pacific islands, but water-laid tuffaceous rocks carrying 

well-preserved and abundant late Eocene Foraminifera 

have been reported from Guam (Cloud and Cole, 1953), 

and forereef outer slope limestone with corals, algae, and 

Eocene Foraminifera has been described from Eniwetok 

(Schlanger, 1963, p. 999-1002).

ACKNOWLEDGMENTS

I am indebted to Dr. Yoshio Kondo of the Bernice P. 

Bishop Museum, Honolulu, Hawaii, and his field assistants, Tomiki and Mosese Yea, for collecting the 

Tongan material. Warren Blow of the U.S. Geological 

Survey prepared most of the fossils herein described. 

All photographs were made by Robert H. McKinney of 

the Geological Survey, some being retouched by Mrs.

387-857 O 70 2

Elinor Stromberg, also of the Geological Survey. During the preparation of the paper, helpful discussions 

were held with Drs. Harald Render and J. P. E. Mcrrison of the U.S. National Museum and with Norman Sohl 

and Druid Wilson of the Geological Survey. The pr/per 

has benefited from critical reviews by Mrs. Katherine 

V. W. Palmer and A. A. Olsson of the Paleontological 

Research Institution, Ithaca, N.Y.

AGE AND CONDITIONS OF DEPOSITION

On the basis of nonmolluscan fossils, the age of the 

Eua deposits is fairly well established as late Eocene 

(Tertiary 6). Both smaller and larger Foraminifera 

support this interpretation (Todd, 1970; Cole 1970). 

Evidence from the calcareous nannoplankton is in general agreement with this determination, though an age 

of earliest Oligocene seems possible (M. N. Bramlette, 

in Todd, 1970, p. A18).

The molluscan fauna contains a variety of Ceno^oic 

genera and subgenera, many of which go back at l^ast 

to Eocene times (table 1). None of the mollusks can be 

identified with still-living species, but the assemWage 

does not have a characteristic "Eocene look." The 

Tongan mollusks are thought to have lived in deeper 

waters than most Eocene mollusks from other ar°,as, 

which may account for their more youthful appearance.

As recorded in the descriptions to follow, a variety of 

mollusks, mostly small, has been recovered and identified, generically or specifically. In addition, there are 

numerous sculptured shell fragments, mostly gastropods, and many molds of minute mollusks, both gastropods and pelecypods. More than half of the identified 

mollusks are represented by a single specimen, and 

many of these are incomplete.

Mollusks commonly found in the shallow waters over 

reef flats and in lagoons are sparsely represented. The 

nine species described as new are listed with their living 

relatives in table 2. The relationship is fairly clos?, in 

four species, less close in four others, and rather distant

Cl
C2 LATE EOCENE FOSSIL

TABLE 1. Geologic range of genera and subgenera of mollusks 

from Eua, Tonga

Scissurella (Anatoma) _ _ __

Sinezona _______ __

Basilissa (Ancistrobasis) 

Bathybembiz _ _ ___ _ _

Astele (Callistele). _ __ _ _

Pareuchelusl _ _____ ____

Daronia (Daronia) _ _ _ _ _ _ _

Lydiphnis. . _ _ _ _____ _

Mathilda (Fimbriatella?) _ _ _ _

Epitonium (Boreoscalal)

Pedicularia (Pedicularia) 

Latirus __ _ __

Cretaceous

 

Eocene

 

Oligocene

 

Miocene

 

Pliocene

 

Pleistocene

 

Holocene

in one species (Cregania). All but three of the related 

Holocene species are from the Indo-Pacific. Five of the 

new fossil species are represented in the collection by a 

dozen or more specimens, and living relatives of four of 

these species range into fairly deep waters. It is difficult 

to evaluate the molluscan evidence, but it seems probable that the limestone represents offreef deposition at a 

depth of about 100 fathoms.

TABLE 2. Distribution and depths of living relatives of new 

Eocene species from Eua, Tonga

Eua Eocene species

tongaensis. 

Do....................

padfica.

Astraea (Bolma) stearnsi...

hoffmehteri.

Living relative Area

. . . S. brevis (Hedley) ..__.. New Zealand. ....

Watson. 

.-- T. (P.) monisoni Ladd- Marshall Islands .

... A. (B.) bartscM (Dall)... Molucca Islands ..

(Melvill and 

Standen) .

Depth (fathoms)

20-434

73-100

50

15-640

0-30

205 

50-90

(')

156

740-1425

1 Beach.

SYSTEMATIC PALEONTOLOGY

Family SCISSURELLIDAE 

Genus SCISSTJRELLA d'Orbigny

d'Orbigny, 1823, Soc. Hist. nat. Paris Mem., v. 1, p. 343.

Type (by subsequent designation, Gray, 1847, List of genera of

Recent Mollusca, p. 146) : Scissurella laevigata d'Orbigny.

Living, Mediterranean Sea.

Scissurella, s.s. is characterized by a flattened spire and 

a slit high on the whorl.

Submenus ANATOMA Woodward

Woodward, 1859, Zool. Soc. London Proc., p. 204. 

Type (by original designation) : Scissurella crispata Fleming. 

Living, North Sea.

Anatoma has a slightly elevated spire and a slit near 

the middle of the whorl.

Scissurella (Anatoma) tongaensis Lade*, n. sp. 

Plate 2, figures 1-4

Shell small, spire moderately high, composed of 3i/£ 

whorls, body whorl large, suture distinct. Periphery of 

whorl near the midpoint, bearing a strong carina, above 

and below which the surface of the whorl is gently convex ; aperture broadly elliptical, inner lip extended below. Sculpture consisting of fine clof°,-set slightly 

flexuous axial threads.

Measurements. Holotype, USNM 650547: diameter 

2.0 mm, height 1.6 mm. Paratype, USNM 650548: diameter 2.1 mm, height 1.9 mm.

The Tongan fossil closely resemblos the living 

Seissurella proximo, Dall (1927, p. 10) that occurs in 

the eastern Atlantic, but the inner lip of the fossil is 

more deeply extended below; the fossil bears stronger 

axial threads below the peripheral carina, but lacks the 

spiral sculpture shown by 8. proximo,. 8. tongaensis 

also closely resembles 8. regia Mestayer (1916, p. 124, 

pi. 12, figs. 3-3c; 1919, p. 130) but lacks the spiral lirae 

ascribed to the Holocene species from the New Zealand 

area.

Occurrence. Represented by 50 specimens, none of 

which shows a complete aperture.

Genus SINEZONA Finlay 

Finlay, 1926, New Zealand Inst. Trans., v. 57, p. 341.

Type (by original designation) : ScMsmope brevis Hedley. Living, New Zealand.

Sinezona kondoi Ladd, n. sp. 

Plate 2, figures 5-8

Shell small, spire composed of 3y2 whor]s, nearly flat; 

apex depressed, body whorl flattened above, broadly 

rounded below, these two parts of the whorl separated 

by a prominent selenizone that is perforated near the 

aperture by an oval foramen. Protoconch smooth, whorls 

of spire with sharply raised regularly spaced axial ribs 

that are of equal prominence above and below the selenizone ; axials conspicuously beaded where crossed by fine 

spiral threads. Umbilicus narrow, deep, smooth within, 

bordered by a sharply elevated edge. Aperture elongateoval.
EOCENE MOLLUSKS C3

Measurements. Holotype, USNM 650549: diameter 

1.7 mm, height 1.2 mm. Paratype, USNM 650550: diameter 1.6 mm, height 1.3 mm.

The Tongan fossil closely resembles the type of the 

genus, S. brevis (Hedley) (1904, p. 90, fig. 16), but is 

much more sharply angled at the selenizone than is the 

shell of the living species from New Zealand.

Occurrence. Represented by 13 specimens. The genus 

has not previously been reported prior to the Pliocene. 

This species is named for Dr. Yoshio Kondo of the 

Bishop Museum through whose efforts the Tongan material was collected.

Family TROCHIDAE 

Genus BASILISSA Watson

Watson, 1879, Linnean Soc. London Jour., v. 14, p. 593.

Type (by subsequent designation, Cossmann, 1888, Catatogue

illustre des coquilles fossiles de rfooene * * * de Paris, v.

3, p. 68) : Basilissa superba, Watson. Holocene, Australia.

Basilissa s.s. has a strong peripheral carina. 

Submenus ANCISTROBASIS Dall

Dall, 1889, Harvard Univ. Mus. Oomp. Zoology, Bull., v. 18, p.

32, 384. 

Type (by monotypy) : Basilissa costulata Watson. Holocene,

Caribbean.

Basilissa (Ancistrobasis) pacifica Ladd, n. sp. 

Plate 2, figures 9-11

Shell small, broadly conical, with a flattened base. 

Protoconch rounded and smooth, consisting of about 

11/2 whorls; spire of about four gently convex whorls. 

Sculpture consisting of close-set, sinuous axial ribs that 

are slightly beaded where they cross finer and more 

numerous spirals. On some shells, one or two spirals 

near the middle of the whorl are larger than the others 

and are more conspicuously beaded where crossed by the 

axials. Suture prominent; periphery of body whorl 

pinched to a sharp edge; base flattened and spirally 

ribbed; umbilicus wide and deep; aperture subquadrate, 

columella smooth, gently curved.

Measurements. Holotype, USNM 650560: height 1.6 

mm, diameter 2.3 mm. Paratype, USNM 650561: height 

1.3 mm, diameter 2.0 mm.

Basilissa (Ancistrobasis} pacifica resembles B. (A.) 

costulata, the Holocene type species of Ancistrobasis, in 

important features, but it is a smaller shell and the 

whorls of the spire are inflated, whereas the spire in B. 

(A.) costulata is slightly concave; likewise, the base of 

the fossil shell is more inflated than that of the living 

species.

I have not seen specimens of B. cossmanni Tate from 

the Eocene of Australia (Tate, 1894, p. 185, pi. 11, fig. 8) 

but it appears to be a larger shell with a higher and more 

flat-sided spire than that of the Tongan species.

Occurrence. Represented by a dozen specimens. The 

related living species, B. (A.) costulata, has been collected from a number of stations ranging in depth from 

119 to 640 fathoms and from one station at a depth of 

only 15 fathoms (Dall, 1881, p. 48; Watson, 1880, p. 

103).

Genus BATHTBEHBIX Crosse

Crosse, 1892, Jour. Conchyliologie, v. 40, p. 288-292. 

Type (by original designation) : Bem^ix aeola, Watson. Holo?ene, 

Japan.

Bathybembix? sp.

Plate 2, figures 12, 13

The recrystallized tips of two trochid shells bear 

axial sculpture suggestive of that shown by several 

living species of Bathybembix, including the type, B. 

aeola (Watson). The figured specimen shows parts of 

six whorls that form a flat-sided cone below the eroded 

protoconch; each whorl bears about 20 regularly spaced 

axial ribs that cross the whorl without curvature; suture 

marked by a spiral ridge slightly stronger than the 

axial ribs.

Measurements. Figured apical fragment, USNM 

650559: diameter 2.0 mm, height 1.4 mm.

Bathybembix includes large, thin-shelled forms. The 

genus is known from Oligocene to Holocene. Living 

species are widely distributed, but none have been found 

in water shallower than 150 feet; from such depths they 

range to more than 3,000 feet. The small Tongan shell 

probably represents a related genus.

Genus TTTRCICA A. Adams

Adams, A., 1854, Zool. Soc. London Proc., p. 37. 

Type (by monotypy) : Turcica monilifera A. Adams. Holocene, 

Morton Bay, Australia.

Submenus PERRINIA H. and A. Adams

Adams, H. and A., 1854, Genera of Recent Mollusca, v. 1, p. 419. 

Type (by subsequent designation, Pil^bry, 1889, Manual of

Conchology, v. 11, p. 15) : Monodonta angulifera A. Adams.

Holocene, Philippine Islands.

Turcica (Ferrinia) blow! Ladd, n. sp. 

Plate 2, figures 14-17

Shell small, conic, turreted; spire consisting of about 

three flattened whorls each with a prominent median 

carina that is extended into a series of flattened, triangular, and slightly upturned spines, 18 on the body 

whorl; at the base of the whorl a thin smooth carina 

extends outward beyond the median carina; between 

the median carina and the overlying suture are three 

secondary spirals; a series of broad slightly oblique 

axial ribs extend across the upper part of the whorl to 

the turned-up extensions of the median carina and 

continue as weakened axials to the peripheral carna; 

base convex, covered by threadlike spirals that are
C4 LATE EOCENE FOSSILS FROM EUA, TONGA

strongest near the periphery; suture deeply impressed; 

aperture subquadrate; imperforate; outer lip extended 

below; columella heavy with an obscure tooth near its 

base.

The apical whorl of the paratype shows traces of fine 

axial sculpture.

Measurements. Holotype, USNM 650567: height 1.5 

mm, diameter 1.7 mm. Incomplete paratype, USNM 

650568: height 1.4 mm, diameter 1.0 mm.

T. Nowi resembles T. morrisonl Ladd that lives at 

shallow depths in the Marshall Islands and has been 

recovered from Holocene and Miocene (Tertiary /) 

sediments in drill holes there (Ladd, 1966, p. 36, pi. 3, 

fig. 18, pi. 4, figs. 1-5). The Tongan shells are smaller 

than those of T. morrisoni, have a more prominent basal 

carina, weaker spirals on the base, and lack the apertural 

lirae that are present in T. nwrrisoni.

Two specimens were recovered, one being incomplete. 

The species is named for Warren C. Blow of the U.S 

Geological Survey, who prepared most of the material 

recently collected at Vaingana.

Genus ASTELE Swainson

Swainson, 1855, Royal Soc. Van Diemensland Papers, v. 3, p. 38. 

Type (by monotypy) : Troctius subcarinatus Swainson, Holocene, 

Tasmania.

Submenus CALLISTELE Cotton and Godfrey

Cotton and Godfrey, 1935, South Australian Naturalist, v. 16, 

no. 2, p. 20.

Type (by original designation) : Astele collision Verco. Holocene, Australia.

Astele (Callistele) sp. 

Plate 3, figures 1-3

Shell minute, trochoid spire with gently convex base; 

aperture subquadrate; umbilicus moderately wide and 

deep. Sculpture consisting of fine spiral threads, about 

six on the lower flat half of each whorl with additional 

but more obscure threads on the upper slightly concave 

half; coarse wavy axial threads are distantly but regularly spaced over all whorls; they override the spiral 

threads but are not beaded at the crossings; axial 

threads thicken near periphery, causing scallops in its 

sharp edge; base with three prominent spiral riblets, 

two near the periphery, the third close to a coarse beaded 

rib that descends into the umbilicus.

Measurements. Figured specimen, USNM 650578: 

height (incomplete) 1.2 mm, diameter 1.7 mm.

The Tongan fossil resembles Astele (Callistele} engebiensis Ladd (1966, p. 37, pi. 4, figs. 11-13) in many 

important features but differs from this form and from

the type species by the possession of the sinuous axial 

threads. The single incomplete Tongan specimen is 

made up of three whorls. It probably represents an undescribed form, but a name is withheld pending the 

discovery of better type material.

Family TTTRBIN1DAE 

Genus ASTRAEA Boding

Roding, 1798, Mus. Boltenianum, pt. 2, p. 79.

Type (by subsequent designation, Suter, 1913, Manual New

Zealand Mollusca, p. 166) : Trochits imperialis Gnielin=!T.

heliotropium Martyn. Holocene, New Zealand.

Subgenus BOLMA Risso

Risso, 1826, Hist. nat. des principales productions de 1'Europe 

meridionale * * *: v. 4, p. 117.

Type (by monotypy) : Turbo rugosa Linnaeus. Folocene, Mediterranean and eastern Atlantic.

Astraea (Bolma) stearnsi Ladd, n. ST. 

Plate 3, figures 6, 7

Shell small, trochoid; protoconch, of about one whorl, 

depressed; spire turreted, consisting of about five flatsided whorls; suture wide and deep; base gently convex, 

nonumbilicate; aperture subcircular, columella arcuate, 

smooth. The first two whorls of the spire nearly smooth 

but with traces of axial sculpture and an incipient 

peripheral cord that becomes a strong, beaded structure 

on later whorls; all but the earlier whorls bear four 

spiral lines of coarse beads in the flattened area between 

the periphery and the suture. Body whorl flattened below the periphery to form a wide band that carries three 

spiral rows of coarse beads; at the base of tr°, band there 

is a beaded cord stronger than those lying above; below 

this cord the base is smooth.

Measurements. Holotype, the only specimen, USNM 

650566: diameter (incomplete) 9.0 mm, height 11.2 mm.

The subgenus Bolma has been recorded from the 

Miocene of Europe, but it has not previously been reported from the Eocene. The Tongan she)! is the first 

fossil occurrence from the Pacific.

The nearest living relative of the Tongan fossil is 

Bolma bartschi Dall (1913, p. 591; 1926, p. 6, pi. 36, fig. 

9) based on a single shell dredged alive from a depth of 

205 fathoms in the Moluccas. The Holocene shell is much 

larger than the fossil, and there are differer?es in sculpture: the living species, for example, lacks the strong 

beaded spirals on the body whorl below th^, periphery; 

it has, instead, numerous wavy spiral threads.

A. (B.) steaa^nsi is named for Dr. Harold T. Stearns 

who collected the first megafossils from th^. rich Vaingaria locality in 1943.
EOCENE MOLLTJSKS C5

Genus PAREUCHELUS 0. Boettger

Boettger, O. 1907, Mitt, siebenb. ver. fiir Nat. zu Hermannstadt

Verb., v. 55, p. 187. 

Type (by original designation) : Euchelus excellens O. Boettger.

Miocene, Hungary.

Pareuchelus? sp. 

Plate 3, figures 8-10

Shell minute, globose, slightly turreted, higher than 

wide. Protoconch not preserved; spire consisting of 

about four inflated whorls, separated by a deep suture. 

Sculpture consisting of strong spiral keels, six above the 

base on the body whorl, the lower four coarser than the 

upper two, crossed and slightly beaded by close-set, 

regularly spaced, sharp, oblique axial ribs; base moderately convex; sculpture the same as rest of whorl, but 

more subdued; nonumbilicate; aperture rounded above, 

its lower edge extended to below the columella to form 

a right-angled plate.

Measurements. Figured specimen, USNM 650577: 

height (incomplete) 1.5 mm, diameter 1.5 mm.

Occurrence. Four incomplete specimens appear to 

represent an undescribed species, but a name is withheld 

pending the recovery of satisfactory type material.

Pareuchelus has a reported range of Eocene to Pliocene and is known from Europe and Indonesia (Keen, 

1960, p. 1267).

Family ADEORBIDAE

Genus DARONIA A. Adams

Adams, A., 1861, Annals Mag. Nat. History, 3d ser., v. 8, p. 244. 

Type (by original designation) : Cyclostrema spirilla A. Adams. 

Holocene, southwest Pacific.

Subgenus DARONIA s.s.

Daronia (Daronia) hoffmeisteri Ladd, n. sp.

Plate 3, figures 11-13

Shell small, spire depressed, planorboid, diameter approximately twice the height; protoconch smooth, followed by 2,1/2 rounded whorls; suture impressed; 

aperture circular, oblique, peristome continuous; 

umbilicus wide and deep, bounded by a distinct spiral; 

sculpture consisting of faint lines of growth.

Measurements. Holotype, USNM 650554: height 

0.9 mm, diameter 1.9 mm.

The type of Daronia. is a larger shell than the species 

here described; it is spirally striate and its last whorl 

becomes disjointed.

D. hofftneisteri appears to be closely related to D. 

jaffaensis (Verco), dredged off the coast of South Australia in 90 fathoms of water (Verco, 1909, p. 270, pi. 

20, figs. 6, 7) and off Tasmania at depths of 50-80 fathoms (Cotton, 1945, p. 158); Cotton chose it as the type 

of Eudaronia. D. jaffaensis has a spiral cord above in

addition to the one bounding the umbilicus, and it has 

a reniform aperture with incomplete peristome.

Occurrence. This is the most abundant mollusk in 

the fauna, being represented by more than 100 specimens. It is named for Dr. J. Edward Hoffmeister who 

mapped the island of Eua and determined its geologic 

history.

Genus MUNDITIELLA Kuroda and Habe

Kuroda and Habe, 1954, Venus, v. 18, no. 2, p. 86, 90-91. 

Type (by original designation) : Cyclostrema ammonocercs A. 

Adams. Holocene, Japan.

Munditiella euaensis Ladd, n. sp. 

Plate 3, figures 14-16 ; Plate 4, figures 1-3

Shell small, diameter exceeding height, upper part of 

spire nearly flat, body whorl descending; suture impressed; aperture semicircular, inner lip greatly extended below; umbilicus moderately wide and deep. 

Sculpture consisting of erect, regularly spaced axial 

ribs, about 20 on body whorl, that extend entirely across 

the exposed parts of all whorls.

Measurements. Holotype, USNM 650564: diaireter 

1.5 mm, height 1.2 mm. Paratype, USNM 650565: diameter 1.4 mm, height 1.0 mm.

M. euaensis resembles M. parryensis Ladd (196(% p. 

78), a species known from the Holocene and late Miocene 

(Tertiary g] of the Marshall Islands, but lacks the secondary axial lines and the obscure spiral ridges of that 

species. M. euaensis is smaller than the Holocene M. 

qualum (Hedley) that has been reported from the Pleistocene of Tongatapu, Tonga, and Eniwetok, Marshall 

Islands (Ladd, 1966, p. 77), and there are differences in 

sculpture: on M. qualum there are spiral threads and 

secondary axial threads, and the body whorl is flattened 

and free of axial ribs immediately below the suture and 

around the umbilicus. M. euaensis also resembles a living 

species from Hong Kong described by Gould (1859, p. 

142) as Liotia asteriscus, but that species has a cariiiated 

body whorl with a spiral rib that encircles the umbilicus.

Occurrence. Represented by 15 specimens, none of 

which is complete. The nearest living relative, M. qualuni, was collected by Hedley (1889, p. 406) from sr.nds 

on the lagoon shore of Funafuti. The Tongatapu and 

Marshall Island occurrences are in shallow-water limestones.

Genus LYDIPHNIS Melvill

Melvill, 1906, Malacological Soc. London Proc., v. 7, p. 25. 

Type (by monotypy) : Cyclostrema euchilopteron Melvill and 

Standen. Holocene, Gulf of Oman.

Lydiphnis vainganaensis Ladd, n. sp. 

Plate 4, figures 4-6

Shell small, nummuloidal; spire strongly depressed, 

consisting of a small rounded protoconch and two to
C6 LATE EOCENE FOSSILS FROM EUA, TONGA

three subsequent whorls; body whorl with two strong 

spiral keels that project from sharp peripheral angles 

above and below; a third but less sharply elevated keel 

is on the upper surface of the whorl midway between 

periphery and suture; upper surface of whorl marked 

with oblique lines of growth; aperture subquadrate, 

umbilicus wide and deep.

Measurements. Holotype, USNM 650576: height 0.8 

mm, diameter 2.2 mm.

L. vainga.naensis is similar to the Holocene type species but lacks the strong secondary spiral sculpture of 

that species. It is proportionately lower (flatter) than 

L. novi-castri (Van Winkle) (1919, p. 9, pi. 1, figs. 11, 

12; Palmer, 1937, p. 48, pi. 2, figs. 4, 5) from the Eocene 

of Virginia.

Occurrence. Represented by four nearly complete 

specimens and two internal molds of calcite.

Family MATHILDIDAE 

Genus MATHILDA Semper

Semper, 1865, Jour. Conchyliologle, v. 13, p. 330

Type (by subsequent designation, Cossmann, 1888, Catalogue

illustr6 des coquilles fossiles de 1'Eocene * * * de Paris, v.

3, p. 309) : Turbo quadricarimtus Brocchi. Pliocene, Sicily.

Subgenus FIMBRIATELLA Sacco

Sacco, 1895, Molluschi * * * del Piemonte e della Liguria, pt.

19, p. 36. 

Type (by original designation) : Cerithium fimftriatuni Michelloti. Late Miocene, Italy.

Mathilda (Fimbriatella?) sp. 

Plate 4, figure 7

Two incomplete shells have the unusual sculpture that 

seems to characterize Fimbriatella. Each of the several 

whorls bears a strong beaded spiral rib that caps a broad 

spiral ridge one-third of the distance above the suture. 

In the narrow band below this major spiral is a single 

secondary spiral; in the broader band above, there are 

two secondary spirals. Surface of shell cancellated by 

fine regularly spaced axial threads that cross the spirals 

at right angles and bead them in the process.

Measurements. Figured specimen, USNM 650551: 

height (incomplete) 2.5 mm, diameter 1.4 mm.

Species of Fimbriatella have been reported from all 

parts of the Tertiary Paleocene to Pliocene (Sohl, 

1960, p. 129).

Genus GEGANIA Jeffreys

Jeffreys, 1884, Zool. Soc. London Proc., p. 365, pi. 27, fig. 10. 

Type (by monotypy) : Gegama pinguis Jeffrey. Holocene, 

Atlantic.

Gegania whipplei ladd, n. sp. 

Plate 4, figures 8-11

Shell small and delicate; protoconch composed of 

four slightly inflated whorls covered by close-set slanted

axial riblets and arranged in an acute, heterostrophic 

coil; spire short, made up of about four inflated whorls, 

the body whorl larger than all the others combined: 

suture wide and deep; aperture elliptical, outer lip thin, 

inner lip reflected toward deep umbilicus. Sculpture 

reticulate, consisting of fine close-set spiral threads that 

are overridden but not 'beaded by more widely spaced 

axial threads.

Measurements. Incomplete holotype, USI TM 650574: 

height 1.7 mm, diameter 1.2 mm. Figured paratype, 

USNM 650575: height (incomplete) 2.6 mm, diameter 

1.9 mm.

The Tongan species with its multiwhored, heterostrophic protoconch and its prominent umbilicus is not 

a typical Gegania. It also differs from the type species 

and others of the genus by having axial threads that 

are less numerous than those in the spiral series.

Occurrence. Represented by a total of eight specimens. All seem smaller than the average of the genus, 

but they probably are mature shells. The species is 

named for the late G. Leslie Whipple who v^as the first 

to recognize Eocene fossils from Eua.

Family CERITHIOPSIDAE 

Genus CERITHIOPSIS s.l.

Cerithiopsis sp. 

Plate 4, figure 12

A single incomplete specimen of a cerithiopsid consists of four whorls of a small slender shell; each whorl 

has two major beaded spirals, the lower one much the 

larger; immediately above the suture is a weak spiral 

thread; base flattened, aperture subcircular.

Measurements. USNM 650573: height (incomplete) 

2.4 mm, diameter 0.9 mm.

The sculpture suggests Orth-ochetus Cossmann, a Cretaceous to Eocene genus questionably assigned to the 

Cerithiopsidae by Wenz (1938, p. 779).

Family EPITONIIDAE 

Genus EPITONIUM Roding

Roding, 1798, Mus. Boltenianum, pt. 2, p. 91.

Type (by subsequent designation, Suter, 1913, Mrnual of New 

Zealand Mollusca, p. 319) : Tur~bo scalaris Linnaeus. Holocene, western Pacific.

Subgenus BOREOSCALA Kobelt

Kobelt, 1902, Iconographie der schalentragenden europ&i'schen 

Meeresconchylein, v. 3, p. 23.

Type (by monotypy) : Scala groenlandica Chermitz (=/Sc«- 

laria, greenlandicum Perry). Holocene, circ^mpolar and 

south to northern Japan, New York.

Epitonium (Boreoscala?) sp. 

Plate 4, figure 13

Fifteen incomplete specimens of a small epitonid are
EOCENE MOLLUSKS C7

tentatively referred to Boreoscala. The figured specimen 

shows six convex whorls that form an apical angle of 

22°; suture prominent, aperture subcircular; imperforate. Sculpture consisting of numerous (19 on last whorl) 

erect, axial lamellae that are slightly bent backward; 

strong spiral threads between lamellae, with traces of 

secondary spirals.

Measurements. Figured specimen, USNM 650572: 

height (incomplete) 4.5 mm, diameter 2.1 mm.

The Tongan species seems to agree in essential features with/?. (B.) greerilatidicum, the much larger type 

of Boreoscala. Other incomplete fossil shells have a more 

acute spire and may represent a second species.

Family XENOPHORIDAE 

Genus XENOPHORA Fischer von Waldheim

Fischer von Waldheim, 1807, Museum Demidoff, ou catalogue 

syst£matique et raisson£ des curiosites de la nature, v, 3, 

p. 213.

Type (by ruling Internat. Comm. Zool. Nomenclature) : Troclius 

concJiyliophorus Born. Holocene, West Indies.

Xenophora sp. 

Plate 3, figures 4, 5

Minute, spire of moderate height, base flattened, 

whorls gently convex; a prominent keel lies immediately above the suture; margin of keel scalloped; upper 

surface of whorls have subcircular depressed areas, apparently the scars of attached objects; base concave 

near periphery; umbilicate. Aperture ovate; part of 

specimen shows fine axial lines.

Measurements. Incomplete1 figured specimen, USNM 

650557: diameter 5.1 mm, height 3.3 mm.

Family OVULIDAE 

Genus PEDICULARIA Swainson

Swainson, 1840, Treatise on malacology, p. 245, 357. 

Type (by monotypy) : Pedicularia, scitula Swainson. Holocene, 

Mediterranean.

Submenus PEDICULARIONA Ire dale

Iredale, 1935, Australian Zoologist, v. 8, p. 101. 

Type (by original designation) : Pedicitlaria stylasteris Hedley. Holocene, Australia.

Pedicularia (Fedicularioua) sp. 

Plate 4, figures 14, 15

A single, apparently worn, specimen is partly filled 

with tightly cemented material, obscuring internal features, but external features indicate clearly that the 

specimen is a pedicularid. The shell is subrectangular 

in outline with an undulating margin whose edge is thin 

anteriorly but thickened posteriorly. The apex is low; 

sculpture consists of somewhat irregular concentric

growth lines and traces of radial' threads; interior surface glossy.

Measurements. USNM 650571: length 11.0 mm, 

width 3.7 mm, convexity 1.9 mm.

The Tongan fossil bears a general resemblance to 

the variable P. pacifica Pease (1868, p. 96, pi. 11, figs. 

17, 18), a species now living in many parts of the western Pacific, but is more delicate, less convex, and Ircks 

the median constriction that characterizes the living 

species. The genus has not previously been found below 

the Miocene. The occurrence in the Tongan Eocene is 

also of interest because species of Pedicularia live today 

on octacorals and scleractinians normally found well 

below coral reef depths.

FAMILY NATICIDAE 

Genus NEVERITA Risso

Risso 1826,. Histoire naturelle des principales productions de 

1'Europe meridionale, v. 4, p. 149.

Type (by monotypy) : Neverita josephinia Risso. Holocene, Mediterranean Sea.

HTeverita? sp.

Plate 4, figure 16

A worn and partly crushed shell of a low-spired naticid is the only representative of the family Naticidae 

found in the Tongan Eocene collection. The occurrence 

is of interest, as the specimen is one of the largest riollusks in the collection and represents a group commonly 

found in the sands of shallow water.

The fossil has the width and the partly covered umbilicus of a typical iieveritid. Its suture appears depressed, but this may be due to crushing.

Measurements. USNM 650552: height 10.0 mm, diameter 11.2 mm.

Family FASCIOLARIIDAE 

Genus LATIRUS Montfort

Montfort, 1810, Conchyliologie systematique, v. 2, p. 531. 

Type (by original designation) : Latirus aurantiacus Montfort 

(= Murex gibbulus Gmelin). Holocene, Australia.

Latirus sp. 

Plate 5, figure 1

An incomplete specimen showing the protoconch and 

about three whorls of the spire preserves sculpture that 

appears to be that of a Latirus. The protoconch consists 

of at least three whorls, the lower two bearing strong, 

close-set axial ribs that parallel the axis of coiling. The 

whorls of the spire bear two major and several minor 

spirals that are coarsely beaded as they cross prominent, 

regularly spaced axial ribs; surface of the whorls between the major beaded axials show traces of fine, closeset axial threads.
C8 LATE EOCENE FOSSILS FROM EUA, TONGA

Measurements. Figured specimen, USNM 650556: 

height (incomplete) 3.3 mm, diameter 2.2 mm.

The sculpture of the spire is similar to that of L. sexcostatus Johnson (1899, p. 74) from the Claibornian, 

middle Eocene, of the Gulf Coast of North America, but 

the Tongan fossil has stronger axial threads.

Family CONIDAE 

Genus CONUS Linnaeus

Linnaeus, 1758, Systema Naturae, 10th ed., p. 712.

Type (by subsequent designation, Children, 1823, Lamarck's

genera of shells, p. 107.) : Conus marmoreus Linnaeus.

Holocene, Indo-Pacific.

Conus sp. 

Plate 5, figure 2

A single cone is small with a moderately high flat 

spire; the shoulder is rounded, the sides of body whorl 

flat; early whorls are scalloped at the suture, this feature 

less prominent on later whorls; anal fasciole concave; 

aperture narrow, widening slightly anteriorly; traces of 

low spirals are preserved anteriorly.

Measurements. USNM 650553; height 15 mm, diameter 7.7 mm; it is the largest gastropod in the extensive Eocene fauna. Most cones are found in warm equatorial waters where they are particularly abundant on 

rocky reef flats and other shallow-water terraces. A few 

cones have been taken alive from depths of 30-40 

fathoms, but the worn condition of the Eocene fossil 

suggests that it was carried to its final resting place from 

shallow water.

Family TERERRIDAE

Genus HASTULA H. and A. Adams

Adams, H. and A., 1853, Genera of Recent Mollusca, v. 1, p. 225. 

Type (by subsequent designation, Cossmann, 1896, Essaisde paleoconchologie comparee pt. 2, p. 53) : Buccinum strigilatum

Linnaeus. Holocene, Indo-Pacific.

Hastula sp. 

Plate 5, figure 3

Small, slender, flat-sided; whorls more than 13; suture distinct, giving the whorls a slight shoulder. Sculpture consisting of low axial ribs that extend without 

curvature from suture to suture, six to seven showing 

in side view; on the youngest whorls the ribs become less 

prominent anteriorly.

Measurements. USNM 650556: height (incomplete) 

8.7 mm, diameter 2.2 mm.

The Tongan fossil bears a general resemblance to H. 

liomala Woodring and H. jamawensis Woodring (renamed H. vautrini by Jung, 1965, p. 594) from the Miocene of Jamaica (Woodring, 1928, p. 143, pi. 4, figs. 4, 

5) but is straighter and more slender than either. It appears to be more closely related to H. lissa Jung from the 

Miocene of Venezuela (Jung, 1965, p. 593, pi. 79, fig. 16),

but the ribs on the Tongan shell are stronger and more 

persistent. Closer comparison must await more complete 

examples of both species.

Family ATYIDAE 

Genus ATYS Montfort

Montfort, 1810, Conchyliologie systematique, v. 2, p. 343. 

Type (by monotypy) : Atys cymbulus Montfort ( = Fulla naucmn 

Linnaeus). Holocene, Indo-Pacific.

Atys? sp. 

Plate 5, figure 4

A single, minute, recrystallized specimen seems to 

represent the Atyidae. It is broadly lenticular in outline, 

widest slightly below the midpoint. The aperture extends full length, widening slightly anteriorly; spire 

concealed, columellar fold obscure; no trace of surface 

sculpture.

Measurements. USNM 650558: height 1.8 mm, diameter 1.1 mm.

The generic position of this specimen is uncertain. In 

general configuration it resembles Atys 'volvulinus (A. 

Adams), a living Japanese species, type of tl Q, subgenus 

Nipponatys Kuroda and Habe (Habe, 1952, p. 141, pi. 

20, fig. 5).

Family PECTINIDAE

Genus PECTEN s.l.

Pecten? sp. 

Plate 5, figure 5

An incomplete, nearly flat valve, USNM 650579, measuring 14 mm in height bears about 15 low rib0 that show 

a tendency to divide into two or three ribs near the 

ventral margin. The shell is the largest of the pelecypods 

but it has few diagnostic features. The valve was possibly carried in from shallow water.

Family OSTREIDAE 

Genus CRASSOSTREA Sacco

Sacco, 1897, I molluschi clei terreni terbziarii de1 Piemonte e 

della Liguria, v. 12, p. 99.

Type (by original designation) : Ostrea virginica- Gmalin. Holocene, eastern America.

Crassostrea sp. 

Plate 5, figures 6-9

Half a dozen shells representing both left and right 

valves of oysters were recovered. All are small and thin, 

and all probably are young shells. Lateral margins are 

smooth, muscle scars obscure. The shells have the characteristic shape of Crassostrea but are not heavy as are 

adult shells of the genus. Shells mostly smooth but have 

irregular lamellar growth lines.
EOCENE MOLLUSKS C9

Measurements. Figured specimens: Plate 5, figures 

6, 7, a left (attached) valve, USNM 650569: length 4.1 

mm, height 5.8 mm, convexity 1.5 mm. Plate 5, figures 8, 

9, a right (upper) valve, USNM 650670: length 5.5 

mm, height 7.5 mm, convexity 1.3 mm.

None of the shells shows any trace of cellular structure such as characterizes salt-water oysters, and it seems 

probable that these light shells were carried seaward 

from the brackish waters of a nearby land area.

Family CORBTTLIDAE 

Genus CORBTTLA Lamarck

Lamarck, 1799, Prodrome d'une nouvelle class, des coquilles,

Soc. Hist. nat. Paris Mem., v. 1, p. 89. 

Type (by subsequent designation, Schmidt, 1818 fide Stewart,

1930, Acad. Nat. Sci. Philadelphia Spec. Pub. 3, p. 286-

.287) : Corbula sulcata Lamarck. Holocene, west coast of

Africa.

Submenus CUNEOCORBULA Cossmann

Gossmann, 1886, Catalogue illustre. des coquilles fossiles de

tl'Eocene. * * * Paris, v. 1, p. 37. 

Type (by subsequent designation, Dall, 1898, Wagner Free Inst.

Sci. Trans., v. 3, pt. 4, p. 838) : Carbula biangulata Deshayes.

Eocene, Paris Basin.

Corbula (Cuneocorbula?) sp. 

Plate 5, figure 10

A single, incomplete, right valve probably represents 

a species of Cuneocorbula. The shell is small, elongate, 

extend posteriorly, slightly truncated anteriorly. A 

strong ridge extends from the umbo to the posterior ventral margin. Sculpture consists of concentric lines that 

are weakly developed over most of the shell but are 

strong on the narrow strip dorsal to the umbonal ridge; 

this discrepancy in sculpture suggests that a second 

ridge may have been present dorsal to the one that is 

preserved.

Measurements. USN'M. 650562: length 6.7 mm, 

height 3.9 mm, convexity (one valve) 1.3mm.

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CIO LATE EOCENE FOSSILS FROM EUA, TONGA

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Schlanger, S. O., 1963, Subsurface geology of Eniwetok Atoll: 

U.S. Geol. Survey Prof. Paper 260-BB, p. 991-1066.

Sohl, N. F., 1960, Archeogastropoda, Mesogastropoda, and stratigraphy of the Ripley, Owl Creek, and Prairie Bluff Formations : U.S. Geol. Survey Prof. Paper 331-A, 151 p. [1961].

Tate, Ralph, 1894, Unrecorded genera of the older Tertiary 

fauna of Australia, including diagnoses of some new genera 

and species: Royal Soc. New South Wales Jour., v. 27, p. 

167-196, 4 pis.

Todd, Ruth, 1970, Smaller Foraniinifera of late Eocene age from 

Eua, Tonga: U.S. Geol. Survey Prof. Paper 640-A, 21 p., 

8 pis., 4 figs.

Van Winkle, Katherine, 1919, Remarks on Virginia Eocene fossils in Van Winkle, Katherine, and Harris, G. D., New or 

otherwise interesting Tertiary molluscan species from the 

east coast of America: Bulls. Am. Paleontology, v. 8, no. 

33, p. 6-12, 1 pi.

Verco, J. C., 1909, Notes on South Australian marine Mollusca 

* * *: Royal Soc. South Australia Trans., v. 3^, p. 270-342.

Watson, R. B., 1886, Voyage of H.M.S. Challenger * * * Scaphopoda and Gastropoda : 756 p., 53 pis.

Wenz, Wilhelm, 19S8-44, Gastropoda, Teil 1, ProsTbranchia, in 

Schindewolf, O. H., Handbuch der Palaozoologie: Berlin, v. 

6, 1639 p., 4211 figs. (pts. 1, 2, 1938; pt. S, 1939; pt. 4, 1940; 

pt. 5,1941; pt. 6,1943 ; pt. 7,1944).

Woodring, W. P., 1928, Miocene mollusks from Bowc'en, Jamaica ; 

Part II, Gastropods and discussion of results: Carnegie Inst. 

Washington Pub. 385, 564 p.
INDEX

[Italic page numbers indicate major references and descriptions]

Acknowledgments .....................

Adeorbidae. _.-..-.........-...........

aeola, Bembix.---. _ .................

Age, Eua deposits. ___ ...............

ammonoceras, Cydostrema-. ............

Anatoma ........ ....................

(Anatoma), Scissurella. .................

tongaensis, Scissurella...............

Ancistrobasis . ................................

(Ancistrobasis) , Basilissa. .....................

costulata, Basilissa... .....................

pacifica, Basilissa..................... 2,3

angulifera, Monodcnta. .......................

Annelids...................................

Astele..... ...................................

(Callistele).. .............................

engebiensis ..........................

sp.-.. -..-...-...--... .....-. 4;

collision....... ...........................

asteriscus, Liotia. .......... ...................

Astraea. ......................................

(Bdma).. ................................

bartschi. ..............................

»tear»»i...... ..................... 2,4

Atyidae.. ....................................

Afys. . ...................................

cymbulus. ......... .......................

volvulinus- ...............................

sp-.....__ _ . . _______ 8

aurantiacus, Latirus ..........................

Page

Cl 

5 

3 

1 

5 

2

2 

; pi. 2

3

2

2.3 

pi. 2

3 

V

4 

2 

4 

pi. 3

4

5

4

2

2.4 

; pi. 3 

8 

8 

8 

8

pi. 5 

7

Barnacles...-...... ........................ V

bartschi, Astraea (Bolma)...................... 2,4

Bolma.................................... 4

Basilissa..................................... 3

cossmanni................................ 3

costulata.................................. 3

superba................................... 3

04ndsf ro&asis) .--.... .-..-.....-...-.. 2

cost wZata.............................. 2,3

pacifica........................... 2,3; pi. 2

BathybemWx.................................. 2,3

sp...................................... 3; pi. 2

Bembii aedla................................. 3

biangulata, Corbula........................... 9

Bibliography................................. 9

6Zown', Turcica..............................^. 4

Turcica (Perrinia).................... 2,3; pi. 2

Bolma... ......._........................... 4

bartschi................................... 4

(Bolma), Astraea.............................. 2

bartschi, Astraea.......................... 2, 4

stearnsi, Astraea. ..................... 2, 4; pi. 3

Boreoscala.................................... 6

(Boreoscala), Epitonium...................... 2

greenlandicum, Epitonium................. 7

sp., Epitonium....... ....__..._..... 6; pi. 4

Brachiopods................................. Ill, V

brevis, Schismope.............................. 2

Stnezona.................................. 2

Bryozoans_..._........................... V

Page 

Buccinum strigilatum......................... C8

BuUa naucum................................ 8

Callistele....--..-............................. 4

(Callistele'), Astele............................. 2

engebiensis, Astele......................... 4

sp., Astele............................... 4; pi. 3

collision, Astele............................... 4

Cerithiopsidae..-............................ 6

Cerithiopsissp.......................... 6;pl. 6

Cerithium fimbriatum......................... 6

conchyliophorus, Trochus...................... 7

Conidae......_............................. 8

Conus........................................ 8

marmoreus................................ 8

sp._--.....--.-.-.-....-..-._-..-.....-. 8; pi. 5

Corals.-...--..-.......-...........-...- V

Corbula....................................... 9

Corbula biangulata............................ S

suleata.................................... 9

(Cuneocorbula) sp....................... 9; pi. 5

Corbulidae...................._............ 9

cossm anni, Basilissa.......................... 3

costulata, Basilissa............................ 3

Basilissa (Ancistrobasis)................... 2, 3

Crassostrea................................... 8

sp...................................... 8; pi. 5

Crinoids .................................. V

crispata, Scissurella........................... 2

Cuneocorbula................................. 9

(Cuneocorbula) sp., Corbula................. 9; pi. 5

Cydostrema ammonoceras..................... 5

euchilopteron.............................. 5

spirilla....--.-.-...--.---------.-.--..--- 5

cymbulus, Atys................................ 8

D 

Daronia...................................... S

hoffmeisteri............................... 5

jaffaensis................................. 2, 5

(Daronia)................................. 2

hoffmeisteri...................... 2,6; pi. 3

(Daronia), Daronia........................... 2

hoffmeisteri,Daronia................. 2,5; pi. 3

Decapod crustaceans... 

Deposition, conditions.

Eua, age_.......

offreef.............

Discoasters............

sp.. ........................

eeoloey of...... .............

V

4

1

6

6

2

7

...... 6; pi. 4

5

1

... Ill

Page 

euaensis, Munditiella............... C2, B; pi. 3, pi. 4

Eucheluseicellens............................. 5

euchilopteron, Lydiphnis....................... 2

Eudaronia.................................... 5

excellens, Euckelus............................ 5

Fasciolariidae.... ............................. 7

Fimbriatetta.. ...... ........................... 6

(Fimbriatella), Mathilda... .................... 2

sp., Mathilda.... ...................... 6; pi. 4

fimbriatum, Cerithium... .......... ... ......... 6

Foraminifera... -- -------- ---- V

Foreword, by H. 8. Ladd.. ------------------ III

G 

Gegania .... _ . .--. - ---- 2,6

pinffMfs...-.--- ----------------------- 6

whipplei.. ...... ................... 2,0- pi. 6

(Geganid) ---------------------------------- 2

gibbulus, Murer... ..... ...... .... . ... ..... - - 7

greenlandicum , Epitonium (Boreoscala) ........ 7

Scalaria. ..... ............. ---------------- 6

groenlandica, Scala ... ...................-.---- 6

H 

Hastula .... ................--.-.-.--

homala... .......................-

jamaicensis. ...........~.-~. ---

lissa. ------------ ----------------

vautrini ... ....... -..- ....------

sp. _..- ----------------

heliotropium, Trochus.... .....................

hoffmeisteri, Daronia.... ............- 

Daronia (Daronia)......--. ........... 2,B

homala, Hastula. ...... .......... -------------

Hydrozoans------- - ---- - -------------------

2,8

8: pi. 5

4

5 

pi. 3

imperialis, Trochus. 

Indo-Pacific.-----

relation to Tonga Trench... __ III

jaffaensis, Daronia.-........------------------ 2, 5

jamaicensis, Hastula-........ ----------------- 8

josephinia, Neverita............ --------------- 7

kondoi, Sinezona... . ... --------------- * P^ 2

L 

Ladd, H. S., Foreword.. .-. -------------- HI

laevigata, Scissurella.------------- - -- --- 2

Latirus... ............... -- - --- 2,7

aurantiacus... . - .---. ------------ 7

seicostatus.------------------------------- %

sp... ............-. TVpl.5

Liotia asteriscus-- ... ----- ------ 5

lissa, Hastula..-..-.-------------------------- %

Lydiphnis------------------------------------ 2,5

euchilopteron- - .. --- --------------- 2

nopf-castrJ-------------------------------- ®

vainganaensis.-------------------------- #.'Pl- 4

Oil
C12 INDEX

M

marmoreus, Conus. ... .-

Mathilda...... ................

(Fimbriatella). .............. .

SP--. --------------- -

Mathildidae........ -...-.-.-.--.

Mollusks. ---._-.----------------

monilifera, Turcka ... ............

Monodonta angulifera ............

morrisoni, Turcka ...............

Turcica (Perrinia) ...........

Munditiella.. ....................

euaensis. ....................

parryensis ...................

qualum . .. -

Murex gibbulus ..................

N

Naticidae... ..--__-.-._.-.--.----

naucum, Bulla. .................

Neverita -....---......-.--.--..--

josephinia- ..................

sp. ...................... ...

Nipponatys...... ................

novi-castri, L ydiphnis ............

O

Oflreef deposition.. ---_...---.,-

Oligocene, early.. __..-.._..... ..

Orthochetus. .....................

Ostracodes .-.-.--.-.....----.-..

Ostrea virginka. .................

O streidae. . ......................

Otollths ..--... -- ----.

O vulidae. .......................

P

pacifica, BasUissa (Ancistrobasis) 

Pedicularia.................. 

Pareuchelus.... ..................

sp.. ........................

parryensis, Munditiella. ...-.--..

Pecten. --......------..----.-.--.

sp.. ........................

Page

............ C8

.---..--...... 6

-....---..-.. 2

............ 61; pl. 4

6

... .. ... V

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

3

.. .. 4

2

2,5

.-.. 2, 5; pl. 3, pl. 4

5

..- ..-..-.... 2,5

. . 7

....-... - 7

...........--- 8

.. .......... r

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

............ 7,-pl. 4

.............. 8

... ... ...... 6

... ...-.-.--. 2

........ ... 1

. .- . .... 6

V

8

. ......... 8

.. .... V

. -.---..-- 7

-.._.-..- 2,S;pl. 2 

.-...-......-. 7 

.............. 2,5

............ 5;pl.3

-....--..-.--- 5

............. 8

 ... . 8;pl. 5

Pectinidae _ .....---.-...---.--..

Pedicularia ........................

pacifica....--..-...--.-.--..-..

stylisteris. .....................

(Pedkularia). .................

sp... ......................

(Pedkularia) , Pedkularia..... .....

sp., Pedkularia. ...............

Pediculariona. .....................

Perrinia ...........................

(Perrinia) blowi, Turcka ... ........

morrisoni, Turcica. .. ..........

Turcka. .......................

pinguis, Gegania. ..................

Plant microfossils __ ... ..........

Q

quadrkarinatus, Turbo. ............

qualum, Munditiella. ...............

 R

regia , Scissurella ...................

rugosa, Turbo. ... ..----.-......---.

S

Scale groenlandica _ . ...............

Scalaria greenlandicum.... .........

scalaris, Turbo....... .... ... ... ....

Schismope brevis ...................

Scissurella.... ... ..................

crispata... ..-..----.----..--.-.

laevigata -----------------------

regia.. .........................

tongaensis .... . .................

(Anatoma) ... ..................

tongaensis .... ..... ... .....

Scissurellidae _ ...................

seicostatus, Latirus. ............... 

Shark teeth.. __ ..-..-...-...---.-

Sinezona ..... ......................

brevis..........................

kondoi. .......................

spirula, Cyclostrema.. ..............

Page

-........._ C8

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

.. . 7

. .... ... 7

o

.......... 7;pl. 4

2

.......... 7;pl. 4

,. ........ 7

S

....... 2,S;pl. 2

2

2

6

V

-...-.--. 6

............ 2,5

.. .... - 2

...-- .- 4

..-....--.- 6

............ 6

.......... 6

............ 2

............ 2

.... 2

2

2

2

2

.......... «;pl.2

2

. . ----- 8 

V

. ------ S

2

.......... 2,'pl. 2

5

Stearns, H. T., quoted..... . .

stearnsi, Astraea (Bolma).. .. ..

strigilatum, Buccinum ... ...... ...

stylasteris, Pedkularia ...... .. ... ..

subcarinatus, Trochus. ............

sulcata, Corbula .... ........... ...

fuperba , BasUissa .................

T

Tele-a-hiva... ....................

Terebridae... -....-....---.......

Tertiary 6..... ...................

tongaensis , Scissurella. ............

Scissurella (Anatoma).........

Trochus conchyliophorus ...... .....

heliotropium.... ..............

imperialis. ....................

subcarinatus.. ... .............

Turbinidae.. ___ ... _ .........

Turbo quadrkarinatus ... ..........

rugosa......... ...............

sealarii. ................ .... ..

Turcka......-..-.-...-.--..-..-..

blowi...... .... ........ __ ...

monilifera. ....................

morrisoni. ....................

(Perrinea).. ... ...............

blowi... .... ---.-.--.....--

morrisoni.. ........... ... .

V

Vaingana. _ ... _ ...............

vainganaensis, Lydiphnis. .........

vautrini, Hastula... ..--....--.---.

virginica, Ostrea ... ................

volvulinus, Atys. ..................

W 

Whipplei Gegania... ..............

X

Xenophora....... .................

SP........ ....................

Xenophoridae. ...................

Page

...---...... Ill

...... C2,4;pl.3

............ 8

-.-.....-.- 7

--.......-.. 4

-...-....-.. 9

...--....-.. 3

............ Ill

.-.-..-....- 8

............ 1

....---.-..- 2

. -..... *; pl. 2

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

.---...-.... 4

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

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

4

6

4

6

S

.... 4

S

..... 4

2

....... 2,3; pl. 2

.-.. .-- 2

...-....-.-- Ill

......... ^ pl. 4

............ 8

8

......... 8

........ 2,6,-pl. 6

............ 2,7

......... 7; pl. 3

............ 7
PLATES 1-5
PLATE 1

[Rock samples showing abundance, diversity, and size range of fossils; X 2]

FIGURE 1. Part of hard unweathered bed. This material is not dolomitized or silicified. 

Some of the elongated fragments (echinoid spines and coral branches) are 

subparallel, suggesting current action.

2. Weathered rock containing small forms and grains of altered volcanic material. 

3, 4. Samples of soft rock that have been etched to bring out corals, Foraminifera, 

and shells (brachiopods and mollusks).
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C PLATE 1

ROCK SAMPLES SHOWING ABUNDANCE, DIVERSITY, AND SIZE RANGE OF FOSSILS
PLATE 2

[All views x 20]

FIGURES 1-4. Scissurella (Anatoma) tongaensis Ladd, n. sp. (p. C2).

I, 2. Holotype, height 1.6 mm, USNM 650547. 

3, 4. Paratype, height 1.9 mm, USNM 650548. 

5-8. Sinezona kondoi Ladd, n. sp. (p. C2).

5, 6. Holotype, height 1.2 mm, USNM 650549. 

7, 8. Paratype, height 1.3 mm, USNM 650550. 

9-11. Basilissa (Ancistrobasis) pacifica Ladd, n. sp. (p. C3). 

9, 10. Holotype, height 1.6 mm, USNM 650560.

II. Paratype, height 1,3 mm, USNM 650561. 

12, 13. Bathybembix? sp. (p. C3).

Diameter 2.0 mm, USNM 650559. 

14-17. Turcica (Perrinia) blowi Ladd, n. sp. (p. C3).

14-16. Holotype, height 1.5 mm, USNM 650567.

17. Paratype, height 1.5 mm, USNM 650568.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C PLATE 2

SCISSURELLIDAE AND TROCHIDAE
PLATE 3

FIGURES 1-3. Astele (Callistele) sp. (p. C4).

Diameter 1.7 mm, X 20, USNM 650578. 

4, 5. Xenophora sp. (p. C7).

Height 3.3 mm, X 8, USNM 650557. 

6, 7. Astraea (Bolma) stearnsi Ladd, n. sp. (p. C4).

Holotype, heignt 11.2 mm, X 4, USNM 650566. 

8-10. Pareuchelusf sp. (p. C5).

Diameter 1.5 mm, X 20, USNM 650577. 

11-13. Daronia (Daronia) hoffmeisteri Ladd, n. sp. (p. C5).

Holotype, diamater 1.9 mm, X 20, USNM 650554. 

14-16. Munditiella euaensts Ladd, n. sp. (p. C5).

Holotype, diameter 1.5 mm, X 20, USNM 650564.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C PLATE 3

16

TROCHIDAE, TURBINIDAE, ADEORBIDAE, XENOPHORIDAE
PLATE 4

FIGURES 1-3. Munditiella euaensis Ladd, n. sp. (p. C5).

Paratype, diameter 1.4 mm, X 20, USNM 650565. 

4-6. Lydiphnis vainganaensis Ladd, n. sp. (p. C5).

Holotype, diameter 2.2 mm, X 20, USNM 650576. 

7. Mathilda (Fimbriatellat) sp. (p. C6).

Height 2.5 mm, X 20, USNM 650551. 

8-11. Gegania whipplei Ladd, n. sp. (p. C6).

8-10. Holotype, diameter 1.2 mm, X 20, USNM 650574. 

11. Paratype, diameter 1.9 mm, X 20, USNM 650575.

12. Cerithiopsis sp. (p. C6).

Height 2.4 mm, X 20, USNM 650573.

13. Epitonium (Boreoscala?) sp. (p. C6).

Height 4.5 mm, X 15, USNM 650572. 

14, 15. Pedicularia (Pediculariona) sp. (p. C7).

Length 11.0 mm, X 5, USNM 650571. 

16. Neverita! sp. (p. C7).

Diameter 11.2 mm, X 4, USNM 650552.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C PLATE 4

ADEORBIDAE, MATHILDIDAE, CERITHIOPSIDAE, EPITONIIDAE, OVULIDAE, NATICIDAE
PLATE 5

FIGURE 1. Latirus sp. (p. C7).

Height 3.3 mm, X 15, USNM 650556.

2. Conus sp. (p. C8).

Height 15 mm, X 3, USNM 650553.

3. Hastulasp. (p. C8).

Height 8.7 mm, X 10, USNM 650556.

4. Atysl sp. (p. C8).

Height 1.8 mm, X 20, USNM 650558.

5. Pectenl sp. (p. C8).

Height 14 mm, X 3, USNM 650579. 

6-9. Crassostrea sp. (p. C8).

6, 7. Attached valve, length 4.1 mm, X 10, USNM 650569. 

8, 9. Upper valve, length 5.5 mm, X 10, USNM 650570. 

10. Corbulasp. (p. C9).

Length 6.7 mm, X 10, USNM 650562.

U.S. GOVERNMENT PRINTING OFFICE :I970 O 387-857
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-C PLATE 5

FASCIOLARIIDAE, CONIDAE, TEREBRIDAE, PECTINIDAE, OSTREIDAE, CORBULIDAE