Geology and Paleontology 

of Canal Zone and 

Adjoining Parts of Panama

Description of Tertiary Mollusks 

(Additions to gastropods, scaphopods, 

pelecypods: Nuculidae to Malleidae)

GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E
Geology and Paleontology 

of Canal Zone and 

Adjoining Parts of Panama

Description of Tertiary Mollusks 

(Additions to gastropods, scaphopods, 

pelecypods: Nuculidae to Malleidae)

By W. P. WOODRING

GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E

A contribution to the history of 

the Panama land bridge

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

V. E. McKelvey, Director

Library of Congress catalog card No. 72-600341

For sale by the Superintendent of Documents, 

U.S. Government Printing Office,

Washington, B.C. 20402

Price: Paper cover $1.75, domestic postpaid; $1.50, GPO Bookstore 

Stock No. 2401-00217
CONTENTS

	Page 

Abstract __ ____._____________._______-____----__-- 453

Introduction. _.______________-_-_____---___-------- 453

Acknowledgments__ _ _______________---_--_-----_-_ 454

Change in age assignment_________________________ 454

New generic and subgeneric names----___ ___-____-__ 454

Faunal summaries-_________________________________ 454

Eocene series.._________________________________ 454

Gatuncillo formation______________________ 454

Marine member of Bohio(?) formation_______ 455

Oligocene series_________________________________ 455

Bohio formation.___________________________ 455

Caimito formation._________________________ 456

Miocene series___--____---______________________ 456

Culebra formation._________________________ 456

Cucaracha formation._______________________ 457

La Boca formation, including Emperador limestone member.___________________________ 457

Alhajuela formation_________________________ 460

Gatun formation___________________________ 461

Chagres sandstone, including Toro limestone

member-________________________________ 465

Description of Tertiary mollusks continued from

chapter D_______________________________________ 465

Gastropods continued from chapter D___________ 465

Family Neritidae-__________________________ 465

Family Vitrinellidae_-__-_-__________________ 467

Family Turritellidae-_____________________ 467

Family Pseudomelaniidae____________________ 468

Family Thiaridae___________________________ 469

Family Cerithiidae._____________________ 470

Descriptions of Tertiary mollusks Continued 

G astropods Continued

Family Architectonicidae____________________ 473

Family Calyptraeidae_______________________ 473

Family Cypraeidae_______________________ 475

Family Ovulidae____-____________-__________ 475

Family Naticidae.__________________________ 475

Family Cassididae._________________________ 476

Family Muricidae_________________________ 476

Family Buccinidae_______-__________________ 477

Family Melongenidae_______________________ 478

Family Xancidae_______-_________-_-------- 479

Family Cancellariidae.______________________ 481

Family Turridae.__________________ 481

Family Acteonidae._________________________ 481

Scaphopods__________________________________ 481

Family Dentaliidae_______________-------__- 481

Family Siphonodentaliidae.__________________ 486

Pelecypods________________________________ 488

Family Nuculidae________________________ 488

Family Nuculanidae________________________ 490

Family Arcidae____________________________- 495

Family Noetiidae.__________________________ 517

Family Glycymerididae___________________ 519

Family Mytilidae___________________________ 522

Family Pinnidae________________________ 525

Family Pteriidae_______________________ 526

Family Isognomonidae______________________ 526

Family Malleidae_________________________ 527

References cited.___________________________________ 528

Index.____________________________________________ 533

ILLUSTRATIONS

[Plates follow index]

PLATES 67-69. Late Eocene mollusks from Gatuncillo formation.

70. Late Eocene mollusks from Gatuncillo formation and marine member of Bohio (?) formation, and late Oligocene

mollusks from Bohio and Caimito formations. 

71-72. Late Oligocene mollusks from Caimito formation, and early Miocene mollusks from Culebra and La Boca formations.

73. Early Miocene mollusks from Culebra, La Boca, and Alhajuela formations, and middle Miocene mollusks from Gatun 

formation.

74. Early Miocene mollusk from La Boca formation and middle Miocene mollusks from Gatun formation.

75. Middle Miocene mollusks from Gatun formation and late Miocene mollusks from Chagres sandstone. 

76-79. Middle Miocene mollusks from Gatun formation.

80. Middle Miocene mollusks from Gatun formation and Costa Rica.

81. Middle Miocene mollusks from Gatun formation.

82. Middle Miocene mollusks from Gatun formation and late Miocene mollusks from Chagres sandstone.

in

GEOLOGY AND PALEONTOLOGY OF CANAL ZONE AND ADJOINING PARTS OF PANAMA

DESCRIPTION OF TERTIARY MOLLUSKS (ADDITIONS TO GASTROPODS, 

SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE)

By W. P. WOODRING

ABSTRACT

Chapter E adds 112 described species and subspecies (a few 

briefly described) to the some 440 covered in preceding chapters: 

27 additional gastropods, 18 scaphopods, and 67 pelecypods in 

10 families. It is estimated that about 125 species are to be 

added in chapter F, the final chapter.

The Arcidae is by far the largest family in the pelecypods so 

far studied: 30 species in six genera. The genus Anadara is the 

largest in that family: 25 species, representing the subgenera 

Hawaiarcaf, Rasia, Tosarca, Grandiaroa, Potiarca, and Cunearca. Potiarca, based on a living western Pacific species, is 

adopted for many American species heretofore assigned to 

Cunearca.

Eighteen of the 27 additional gastropods were found at a new 

locality in the late Eocene part of the Gatuncillo formation. 

They are assigned to 16 genera, 14 of which are not represented 

at other Gatuncillo localities. The genera include Faunus, Tympanotonos, and Besanconia, which are rare in America, and the 

rare endemic American genus Harrisianella.

The marine member of the Bohio(?) formation is now assigned to the late Eocene, instead of late Eocene or early Oligocene the only change in age assignment. Eocene affinities are 

especially strengthened by the presence of Samanoetia samanensis and Volvariellaf, if indeed the unnamed species represents 

that genus, as seems likely. Both the marine member of the 

Bohio( ?) and the late Oligocene part of the Bohio contain early 

small species of Anadara, subgenus Rasia.

The fossils from the moderately deep-water facies of the late 

Oligocene Caimito formation include the earliest hexagonal Den* 

talium of the subgenus Dentalium s.s., from the American mainland, and a widespread and abundant species of the essentially 

deep-water subgenus Fissidentalium.

Anadara chiriquiensis chiriquiensis, a relatively small form 

of the subgenus Grandiarca that is widely distributed in the 

Miocene Caribbean province, occurs in the Culebra formation. 

For the most part it indicates brackish water.

Among the fossils from the La Boca formation proper, Cyphoma aff. C. intermedia is the earliest representative of an 

endemic American genus, and Isognomon mimeticus, a remarkable, narrowly mytiliform species is the type of the new subgenus Mimonion. Both the Culebra and La Boca, both of early 

Miocene age, contain predecessors of Gatun species.

As in other chapters, the largest number of species is from the 

middle Miocene Gatun formation: 50 species. Bailya orossata 

is the first Tertiary species of the genus from the Caribbean 

region, and the earliest now known. A bizarre, incomplete gastropod is described as xancid?, genus?. The Gatun contains 13

of the 24 species of Anadara and half of the 12 species of the 

subgenus Rasia of that genus. In consideration of two battered 

and worn specimens of a large form of the subgenus Grandiarca, identified as Anadara grandis patricia?, the similar Tertiary forms in the Caribbean region are reviewed and divided 

into a brackish-water group and a marine group. The Gatun 

fauna now totals some 330 species.

INTRODUCTION

Chapter E covers 112 species and subspecies, distributed as follows:

Species and subspecies of mollusks described in chapter E

Number of

species and

Formation

Eocene series:

Gatuncillo 

Marine member of Bohio 1 (?) 

Oligocene series:

Bohio x _________ 

Caimito ______ 

Miocene series:

Culebra ___ 

La Boca proper__ 

Alhajuela _ _ 

Gatun 2 _______ 

Chagres proper_ .

22

8

5

7

7

23

5

50

6

1 In Spanish orthography Bohio. 

3 In Spanish orthography Gattin.

The original list of fossil localities was published on 

pages 112-130 of chapter A, but others were added in 

succeeding chapters, except the present one.

In the distribution tables the designation "sp." in 

locality columns indicates an incomplete or poorly preserved species that may or may not be the same as that 

in the species column, and the designation " ?sp." indicates that the genus is questioned. Symbols for relative 

frequency are as follows:

Symbols used for relative frequency

Number

of 

Symbol specimens

R, rare________ 1-2

F, few________ 3-5

C, common______ 6-20

A, abundant ___ >20

453
454 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

ACKNOWLEDGMENTS

I am indebted to my colleague Druid Wilson for advice, especially concerning the family Arcidae and the 

genus Exputens, and to members of the staff of the 

Division of Mollusks, National Museum of Natural 

History. Dr. Katherine V. W. Palmer and Dr. Horace 

G. Eichards provided facilities for the examination of 

collections at the Paleontological Research Institution 

and the Academy of Natural Sciences of Philadelphia, 

respectively.

CHANGE IN AGE ASSIGNMENT

As provisionally forecast in chapter D (p. 305), the 

age assignment for the marine member of the Bohio (?) 

formation is changed from late Eocene or early Oligocene to late Eocene.

It should be understood that the age assignments are 

Lyellian ages, not planktonic foraminiferal ages. For 

the Neogene of America, planktonic foraminiferal ages 

are almost invariably too young in terms of Lyellian 

ages.

NEW GENERIC AND SUBGENERIC NAMES

The following new generic and subgeneric names are 

proposed.

Charadreon, Pseudomelaniidae ?

Type: Charadreon leptus Woodring, n. sp., Gatuncillo formation, Eocene, p. 469. Gender masculine.

Leptomurex, Muricidae, Ocenebrinae ?

Type: Leptomurex acares Woodring, n. sp., Gatuncillo formation, Eocene, p. 476. 'Gender masculine.

Lissa/rwcula, subgenus of Ewiucula, Nuculidae.

Type: Nucula (Nuculopsis) Mlli Woodring, Bowden formation, Jamaica, Miocene, p. 489. Gender feminine.

Mimonion, subgenus of Isognomon, Isognomonidae. 

Type: Isognomvn (Mimoniori) mimeticus Woodring, n. sp., La Boca formation, Miocene, p. 526. 

Gender masculine.

FAUNAL SUMMARIES

EOCENE SERIES 

GATUNGILLO FORMATION

The species from the Gatuncillo formation are listed 

in the following table. They include 19 collected by 

Mr. R. H. Stewart, geologist of the Panama Canal 

Company, and his assistants at a new locality on the

upper course of Rio Palenque, 3.4 km west of Nuevo 

San Juan. This locality was mentioned on pages 303 

and 304 of chapter D, and was entered on page 301 as 

report locality 23b. According to a communication from 

Mr. Stewart, the Gatuncillo formation, consisting of 

conglomerate, siltstone, and silty mudstone, rests with 

marked unconformity on dark gray and green siliceous 

limestone of the basement complex. The fossils represent 

an unusual mixed shallow-water and moderately shallow-water biofacies unusual for the Gatuncillo formation. Fifteen of the Gatuncillo genera so far covered 

were not found at other Gatuncillo localities. Though 

the matrix consists of silty mudstone, it contains no 

foraminifera or ostracodes. Faunus now lives at the 

mouth of rivers in the western Pacific area and 

Tympanotonos in the same habitat along the coast of 

tropical western Africa.

Additional gastropods and pelecypods (Nuculanidae to Malleidae) 

from Gatuncillo formation

Gastropods:

Nerttina ectypha Woodring, n. sp.

Teinostoma (Idioraphe) elachisCharadreon leptus Woodring, n.

OTI

Faunus xenicus Woodring, n. sp. 

Potamidesfmicraulax Woodring,

Hannatoma antyx Woodring, n.

Tympanotonos acanthodes WoodHarrisianetta camptica WoodBezanconia cosmeta Woodring,

Calyptraea lispa Woodring, n. sp. 

Globularia (Olobularia) megista

Leptomurex acares Woodring, n.

Pelecypods:

Glycymeris (Olycymeris) cf. 0.

Exputens bostrychodes Woodring

Localities

Madden 

basin

9

F

11

B

12

R

R

Rfo Palenque

23b

R 

A 

C 

R

A 

A

A 

A

F 

A 

A 

A

A 

C

A

R 

R 

R

R

Rfo

Frfjol 

area

32

R 

R

R

Cerro 

Pelado

37a

R

Rfo

Casaya 

area

38

R

1 Recorded on p. 68 as Hannatomat cf. H. emendorferi Olsson. 

4 Not described.

Several of the gastropods from locality 23b are noteworthy. So far as I am aware, the operculum of Neritina ectypha, which was in place in the aperture of a 

shell, is the first fossil Neritina operculum to be recorded from America. Charadreon leptus, the type of a 

new genus of uncertain affinities, is represented by an 

estimated thousands of specimens and Hannatoma
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALLEIDAE 455

antyx by some 300. Faunus, Tympanotonos, and Bezanconia are rare in America, and Harrisianella is a rare 

Eocene endemic American genus. Leptomurex acares is 

the type of a new muricid genus. Its suture is not in the 

expectable location, but is a third of the way up the preceding whorl. An unnamed new species of Gymia is the 

earliest species of the subgenus Tritonopsis and of Gymia itself.

An unusual species of the Eocene genus Exputens, E. 

bostrychodes, was collected in Madden basin and in the 

Rio Frijol area.

Bayania, Gharadreon, Hannatoma, Harrisianella, 

Bezanconia, Globularia, Leptomurex, Tritonopsis, and 

Exputens are extinct.

Though all except one of the unequivocally identified 

species and also the unnamed Gymia are endemic, several others are related to species that occur elsewhere, 

as shown in the following table.

Mollusks from Gatuncillo formation and occurrence elsewhere of 

same or related species

Species from Gatuncillo formation

Gastropods: 

Nerita listrota Woodring,

n.sp. 

Teinostoma (Idioraphe)

elachistum Woodring, n.sp. 

Bayania epelys Woodring,

n.sp.

Faunus xenicus Woodring,

n.sp. 

Hannatoma antyx Woodring,

n.sp.

Tympanotonos acanthodes 

Woodring, n.sp.

Harrisianetta camptica 

Woodring, n.sp.

Bezanconia cosmeta Woodring, n.sp.

Globularia (Globularia) 

megista Woodring, n.sp.

Cymia (Tritonopsis) n.sp.

Pelecypod:

Glycymeris (Glycymeris) cf. 

G. caracoli Anderson.

Occurrence elsewhere of same or related

N. planospira Anton, Holocene. 

T. harrisi Palmer, middle

Eocene, Virginia. 

B. lactea (Lamarck), early to

late Eocene, western

Europe. 

F. ater (Linn6), Holocene.

H. emendorferi Olsson, late

Eocene, Peru, Colombia,

Venezuela. 

T. sp., middle Eocene,

Jamaica. 

Late Eocene, Tonosi area,

Panama. 

B. spirata (Lamarck), middle

Eocene, western Europe. 

G. recurva dumblei (Heilprin),

middle Eocene, Texas. 

C. subalveata (Conrad), early

Oligocene, Mississippi.

G. caracoli Anderson, late 

Eocene, Colombia.

MARINE MEMBER OF BOHIO(?) FORMATION

The table below lists the species from the marine 

member of the Bohio(?) formation. (For objections 

to that stratigraphic designation see page 304 of chapter D.) The identification of the unnamed Volvariella? 

is questioned solely because the columella is unknown. 

If it is a Volvariella, it is the youngest and largest species. Gadulus dolichus and the unnamed species are the 

earliest species of the subgenus G-adilopsis. Despite its 

age, Saccella phlyctaena is more similar in size and outline to S. acuta, which ranges from Miocene to the present time, than younger species of the genus in the 

faunas under consideration. Anadara carmanensis and 

the unnamed species are early small species of the subgenus Rasia. Samanoetia samanensis, the most characteristic species, was found in the three areas where this 

unit is recognized and was collected at Vamos Vamos 

by every collector who visited that now submerged locality, beginning with Alexander Agassiz in 1891 and 

ending with MacDonald and Vaughan in 1911.

Eocene affinities are strengthened by the presence of 

Anadara carmenensis, which occurs in late Eocene deposits in Colombia, /Samanoetia samanensis, found in 

the late Eocene of Peru, and presumably by Volvariella?. Samanoetia and presumably Volvariella? are 

extinct.

An additional gastropod, scaphopods, and pelecypods (Nuculanidae 

to Noetiidae) from marine member of Bohio (?) formation

Gastropod: 

Volvariellat sp _ . _ . ......

Scaphopods:

Dentalium (LaevidenCadulus (GadUopsis)

Pelecypods: 

Saccella phlyctaena WoodAnadara (Rasia) carmenenSamanoetia samanensis

Localities

Vamos Vamos

40

F

R

40a

F

F

40b

R

40d

?R

A

F

F

40e

R

....

Palenquilla 

Point

41

R

F

F

41a

....

F

41b

F

R

F

F 

R

C

Trinidad 

Island

42

F

C

R

42a

 -

C

42c

R

....

' Not described.

OLIGOCENE SERIES

BOHIO FORMATION

The few species from the upper part of the Bohio 

formation on Barro Colorado Island are as follows:

Scaphopods and pelecypods (Nuculanidae to Arcidae) from upper 

part of Bohio formation on Barro Colorado Island

Scaphopods :

Pelecypods :

Portlandia (Portlandellaf) euthynta Woodring, 

n.sp _____________-_---__----------------

Anadara (Rasia) lita Woodring, n.sp. _______--_

Localities

42d

R

R

C

C

42g

R

42i

R
456 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Adrana stena is related to A. crenifera, now living in 

the eastern Pacific Ocean, and Anadara lita to the 

Oligocene species^L. mississippiensis.

CAIMITO FORMATION

Barbatia cf. B. cancellaria (loc. 55b) is the only 

species from the shallow-water facies of the Caimito 

formation. It occurs also in the La Boca formation and 

is related to B. cancellaria^ living in the Caribbean 

region.

The fossils found in the moderately deep-water facies 

of the Caimito on Barro Colorado Island are listed 

below. Dentalium armillatum proterum, a forerunner 

of the Gatun nominate subspecies, is the earliest hexagonal species of the subgenus Dentalium s.s. to be 

recorded from the American mainland. D. uscarianum, 

assigned to the subgenus Fissidentalium, was found at 

six localities, as many as some 30 fairly complete specimens and about 100 fragments of varying size at a locality. The modern species of Fissidentalium for the most 

part live in deep water: 600 to 1,800 fathoms in the western Atlantic, but as shallow as 35 to 110 fathoms in the 

same region (Henderson, 1920, p. 61-65). Though Acila 

istJimica istJimica occurs in the Caimito, it ranges 

through the Miocene in the Canal Zone.

Scaphopods and pelecypods (NucuKdae to Nuculanidae) from 

moderately deep-water facies of Caimito formation on Barro 

Colorado Island

Scaphopods. 

Dentalium (Dentalium) armillatum 

proterum Woodring, n. subsp ___ ..

Dentalium (Fissidentalium ) uscarianum 

Olsson.. _ ...............

Pelecypods: 

Nucula (Nucula) cf. AT. spheniapsis 

Conrad.. __ ___ __ .. __

Acila (Acila) isthmica isthmica (Brown 

and Pilsbry) _----_-_--_.___._.______

JupUeria aipeia Woodring, n. sp_..--._

Saccella cf. S. subcerata (Woodring). ...

Localities

54g

F

64h

n

c

F

F

64j

F

54k

n

A

F 

0

R

641

F

F

54m

F

R

R

54n

sp.R

R 

R

The occurrence elsewhere and in other Canal Zone 

formations of Caimito fossils of moderately deep-water 

facies, and the affinities of others are as follows:

Mollusks from moderately deep-wzter fades of Caimito formation 

and occurrence elsewhere and in other Cxnzl Zone formations of 

same or related species

Species from Caimito formation

Scaphopods:

Dentalium (Dentalium) armillatum proterum Woodring, 

n. subsp. 

Dentalium (Fissidentalium)

uscarianum Olsson. 

Pelecypods:

Nucula (Nucula) cf. N. 

spheniopsis Conrad.

Acila (Acila) isthmica 

isthmica (Brown and 

Pilsbry).

Jupiteria aipeia Woodring,

n.sp. 

Saccella cf. S. subcerata

(Woodring).

Occurrence elsewhere and in other Canal 

Zone formations of same or related 

species

D. armillatum armittatum 

Toula, Gatun formation.

Early Miocene, Costa Rica. 

Also La Boca formation.

N. spheniopsis Conrad, late 

Eocene to early Oligocene, 

Mississippi.

Early Miocene, Colombia; 

middle Miocene, Costa Rica, 

Venezuela. Also La Boca 

and Gatun formations and 

Chagres sandstone.

J. brocchii (Bellardi), Miocene, 

Italy.

S. subcerata (Woodring), 

middle Miocene, Jamaica.

MIOCENE SERIES 

CULEBRA FORMATION

The present chapter covers 11 species from the early 

Miocene Culebra formation, which crops out only in the 

Gaillard Cut area along and near the Canal. One, 

however (the only gastropod), was already recorded 

and three others, identified only at the generic level, are 

not described. The species are listed in the accompanying table.

The unnamed, poorly preserved Anadara is doubtfully assigned to the central and western Pacific subgenus Hawaiarca, which is represented in the Caribbean region by very small species of early and middle 

Miocene age and occurs also in the late Miocene and 

Pliocene of Florida. Anadara dariensis progonica is a 

small predecessor of the Gatun nominate subspecies. 

Anadara cMriquiensis chiriquiensis, a greatly overnamed small form of the subgenus G-randiarca, occurs 

in the Culebra. It is widespread in the Miocene of the 

Caribbean region, as well as in Peru. For the most part 

it indicates brackish water. Despite its trivial name, the 

type locality is in the Rio Changuinola district of the 

Bocas del Toro area, in the extreme northwestern part 

of Panama. Though Mytilus canoasensis vidali is identified in the La Boca, AJhajuela, and Gatun formations, 

the best representation is in the Culebra.
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIBAE 457

Gastropod (corrected name) and pelecypods (Nuculidae to Mytilidae) from Culebra formation of Gaillard Cut area and occurrence in

La Boca formation

Gastropod (corrected name) :

Pelecypods : 

Acila sp.2 _______ __ ___ _ _ .

Saccella sp. (fine sculpture) 2 ____ __

Saccella aff. S. balboae (Brown and 

Pilsbry). ____ ___ ___ __ __ _

Adrana sp.2 __ ____ _ _______ __

Anadara (Hawaiarcaf) sp__ ___ _____

Anadara (Rasia) dariensis progonica 

Woodring, n. subsp__ _ __ ____ _

Anadara (Rasia) athroa Woodring, n. 

sp ___ ______ _ __ _______ __ _

Anadara (Grandiarca) chiriquiensis

Anadara (Grandiarca) balboai (Sheldon) 

Mytilus canoasensis vidali Ferreira and 

Cunha_---___ ________________

Localities

102

R

R 

R

?R

102a

R,

103

R,

IMa

R

104b

R

106

R,

F 

A

107

F

108c

R,

C

109

Rsp

R

110

A

A

HOa

F

?R

Ilia

C 

R,

lllb

F

112

C

112a

C

La 

Boca formation

X

X

X

X 

X

i Recorded on p. 286 as Xancus cf. X. rex Pilsbry and Johnson. 

3 Not described.

The occurrence elsewhere and in other Canal Zone 

formations of the same or related species is shown in 

the following table:

Mollusks from Culebra formation and occurrence elsewhere and in 

other Canal Zone formations of same or related species

Species from Culebra formation

Gastropod:

Xancus cf. X. validus 

(Sowerby) - 1

Pelecypods: 

Saccella aff. S. balboae 

(Brown and Pilsbry).

Anadara (Rasia) dariensis 

progonica Woodring, n. 

subsp.

Anadara (Rasia) athroa 

Woodring, n.sp.?

Anadara (Grandiarca) 

chiriquiensis chiriquiensis (Gabb).

Anadara (Grandiarca) 

balboai (Sheldon).

Occurrence elsewhere and in other Canal 

Zone formations of same or related species

X. validus (Sowerby), early 

Miocene, Dominican Republic, Haiti. Also La Boca formation proper and Emperador 

limestone member.

S. balboae (Brown and Pilsbry), 

Gatun formation, middle 

Miocene, Costa Rica. Also 

La Boca formation.

A. dariensis dariensis (Brown 

and Pilsbry), Gatun formation, middle Miocene, Costa 

Rica, Darie"n area, Panamd, 

Colombia, Dominican 

Republic, Perti; late Miocene, 

Panamd. Also La Boca 

formation.

A. athroa Woodring, n.sp., La 

Boca formation.

Early Miocene, Haiti, Peru; 

middle Miocene, Panama1 , 

Peru; middle (?) Miocene, 

Haiti, Venezuela; middle or 

late Miocene, Dominican 

Republic.

A. chiriquiensis chiriquiensis 

(Gabb.) For distribution see 

above. Also La Boca formation.

Recorded on p. 286 as Xancus cf X. rex Pilsbry and Johnson.

Mollusks from Culebra formation and occurrence elsewhere and in 

other Canal Zone formations of same or related species Continued

Species from Culebra formation

Pelecypods Continued 

Mytilus canoasensis vidali 

Ferreira and Cunha.

Occurrence elsewhere and in other Canal 

Zone formations of same or related species

Early Miocene, Brasil; middle (?) 

Miocene, Venezuela. Also 

La Boca, Alhajuela, and 

Gatun formations.

CUCARACHA FORMATION

Unidentifiable molds of Anadara were found in black, 

carbonaceous shale of the Cucaracha formation at locality 122.

LA BOCA FORMATION, INCLUDING EMPERADOR 

LIMESTONE MEMBER

Twenty-three described species in the present chapter 

added to the 48 in preceding chapters bring to 71 the 

total for the early Miocene La Boca formation proper. 

This total does not include 35, for the most part identified only at the generic level, that are recorded, but not 

described.

Five of the gastropods in the accompanying table 

were already recorded, as noted in the table footnotes. 

Cyphoma aff. C. intermedia is the earliest representative of the endemic American genus Cyphoma. The La 

Boca fossils include Dentaliwm uscarianum, a species 

of the subgenus Fissidentalium that occurs also in the 

moderately deep-water facies of the Caimito formation. 

Isognomon mimeticus, a remarkable narrowly mytiliform species, is the type of the subgenus Mimonion. 

Externally it mimics specimens of intermediate size 

of Mytilus canoasensis vidali. So far as known, 

Mimonion is extinct.
458 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Additional gastropods, scaphopod, and pelecypods

Gastropods : 

Nerita (Neritaf) sp_____________ _ _______________ __ __

Turritella collazica Maury J _ _ _ ___ _ _ ____ _ ____ ___ _

Turritella subgmndifera Dall 2 _____ _________

Architectonica (Architectonica) nobilis Roding, subsp.3 __ ________

Trochita sp.4_____ _____

Cyphoma aff . C. intermedia (Sowerby) _ _____ _____ ___ _ _

Semicassis (Echinophoria) tostoma Woodring, n. sp_ _ _ ___

Xancus cf.X.validus (Sowerby 1) 5 --- ------ _______ _____ _

Scaphopod: 

Dentalium (Fissidentalium) uscarianum Olsson ______________

Pelecypods :

Saccella sp. (fine sculpture) 6 _ __ __ ____ ____ _ __ _ ___

Saccella sp. (elongate) 6_ ____ _ ____ _______________ ____ __

Saccella aflf. S. balboae (Brown and Pilsbry) _ __ _ ______

Adrana sp.6 _______________ __ __ ___

Barbatia (Barbatia) cf. B. cancellaria (Lamarck). ___ _____ _

Acar domingensis (Lamarck) ?______ __ _ ___

Anadara (Rasia) dariensis progonica Woodring, n. subsp __ ____

Anadara (Rasia) athroa Woodring, n. sp_ _______ ___________

Anadara (Grandiarca) balboai (Sheldon) _ ___ __ _ _ _____ _

Glycymeris (Glycymeris) carbasina Brown and Pilsbry______ ____

Glycymeris (Tucetona) sp.6_______ ___ _______________ _______

Glycymeris (Tucetona) pedinata canalis Brown and Pilsbry ?_

Mylilus canoasensis vidali Ferreira and Cunha. _ __ ___________

Pteria inornata (Gabb)?_ _ _ ______ ___ ____ _____ _______

Localities

99a

?sp.R

99b

F

R

C

A

99c

R 

F

C

99d

R

F

R

99f

F

R

?sp.R

R 

R

99g

R

F

R

R

99h

R

100

R

R

1 Recorded on p. 98 as TurriteUa cf. T. collazica Maury. 

! Recorded on p. 105 as Turritella cf. T. subgrundifera Dall.

3 Recorded on p. 165 as Architectonica (Architectonica) cf. A. nobilis ROding

4 Recorded in list on p. 37 as TrochUat cf. T. trochiformis (Born).
GASTROPODS, SCAPHOPODS, PELEiCYPODS I NUCULIDAE TO MALLEIDAE 

(Nuculidae to Isognomonidae) from La Boca formation proper

459

Localities Continued

lOOa

?F

lOOb

R

R

101

F

lOla

R

lOlh

c

A

R 

A

F

F

R

lOli

F

A 

F

R 

R

114

R

R

115

R

115a

?sp.R

R

R

115b

?sp.R

R

R

C

116

F

C

R

life

C 

R

F 

A

R

C 

R

A

A

R

C 

A

R

F

119

R

R

119c

R

125

C 

R

F

127

R

127b

R

128

C

F

5 Recorded on p. 286 as Xancua cf. X. rex Pilsbry and Johnson. 

»Not described.
460 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

The table below lists the occurrence elsewhere and in 

other Canal Zone formations of the same or related 

species.

Mollusks from La Boca formation proper and occurrence elsewhere 

and in other Canal Zone formations of same or related species

Species from La Boca formation proper

Gastropods: 

Turritella collazica Maury L.

Turritella subgrundifera Dall 2 _

Architectonica (Architectonica) nobilis Roding, subsp.3 

Cyphoma afif. C. intermedia

(Sowerby). 

Scaphopod: 

Dentalium (Fissidentalium)

uscarianum Olsson. 

Pelecypods:

Acila (Acila) isthmica isthmica (Brown and Pilsbry).

Saccella afif. S. balboae 

(Brown and Pilsbry).

Barbatia (Barbatla) cf. B. 

cancellaria (Lamarck).

Acar domingensis (Lamarck) ? _

Andara (Rasia) dariensis 

progonica Woodring, n. 

subsp.

Anadara (Rasia) cf. A. 

medioamericana (Olsson).

Anadara (Rasia) athroa

Woodring, n. sp. 

Anadara (Tosarcd) campta

Woodring, n. sp.

Anadara (Grandiarca) balboai 

(Sheldon).

Anadara (Potiarca) afif. A. 

chavezi (Engerrand and 

Urbina).

Glycymeris (Glycymeris) 

carbasina Brown and 

Pilsbry.

Occurrence elsewhere anr] in other

Canal Zone formations of same or

related species

Late Oligocene, Puerto Rico.

Also Emperador limestone

member. 

Early to middle Miocene,

Florida ; early Miocene,

northeastern Me'xico. 

A. nobilis nobilis Roding,

early Miocene to Holocene.

C. intermedia (Sowerby), 

Holocene.

Early Miocene, Costa Rica. 

Also Caimito formation.

For distribution see table for 

Caimito formation. Also 

Caimito and Gatun formations and Chagres sandstone.

Saccella balboae (Brown and 

Pilsbry). Gatun formation, 

middle Miocene, Costa 

Rica. Also Culebra 

formation.

B. cancellaria (Lamarck), 

Holocene. Also Caimito 

formation.

Acar domingensis (Lamarck), 

Early Miocene to Holocene.

A. dariensis dariensis (Brown 

and Pilsbry), Gatun 

formation. For distribution 

see table for Culebra 

formation. Also Culebra 

formation.

A. medioamericana (Olsson), 

middle Miocene, Costa 

Rica.

Questionably also Culebra 

formation.

A. santarosana geraetera 

(Gardner), early Miocene, 

Florida.

A. chiriquiensis chiriquiensis 

(Gabb). For distribution 

see table for Culebra 

formation. Also Culebra 

formation.

A. chavezi (Engerrand and 

Urbina). For distribution 

see table for Gatun 

formation.

For distribution see table for 

Gatun formation. Also 

Gatun formation.

Mollusks from La Boca formation proper and occurrence elsewhere 

and in other Canal Zone formations of same or related species Con.

Species from La Boca formation proper

Pelecypods Continued 

Glycymeris (Tucetona) 

pectinata canalis Brown 

and Pilsbry?

Glycymeris (Tucetona)

secticostata schencki Nicol.

Mytilus canoasensis vidali 

Ferreira and Cunha.

Brachidontes sp.

Modiolus americanus

(Leach)? 

Botulafusca (Gmelin)?.

Pteria inornata (Gabb)?.

Occurrence elsewhere and in other

Canal Zone formations of same or

related species

G. pectinata canalis Brown 

and Pilsbry, Gatun formation. For distribution see 

table for Gatun formation.

G. secticostata secticostata 

Nicol, middle Miocene, 

Costa Rica; late Miocene, 

Panamd. Also Gatun formation and Chagres 

sandstone.

Early Miocene, Brasil; 

middle (?) Miocene, Venezuela. Also Culebra, 

Alhajuela, and Gatun 

formations.

B. mississippiensis (Conrad), 

Oligocene, Mississippi, 

Alabama.

M. americanus (Leach), 

Holocene.

B.fusca (Gmelin), Miocene 

to Holocene.

P. inornata (Gabb). For distribution see table for 

Gatun formation.

i Recorded on p. 98 as TurrUetta cf. T. cottazka Maury.

a Recorded on p. 105 as Turritetta cf. T. subgrundifera Dall.

» Recorded on p. 165 as Architedonka (ArchUectonica) cf. A. nobilis Roding.

Before the flooding of Gatun Lake, MacDonald collected Anadara dariensis progonica and Modiolus 

americanus? from limestone on Eio Chagres near the 

former site of Las Cruces (loc. 94). Both of these fossils are listed in the tables for the La Boca formation 

proper. The limestone may represent overlapping strata 

of the La Boca formation, although the La Boca has not 

been recognized in nearby areas.

Turritella collazica occurs in the Emperador limestone members of the La Boca in the Gaillard Cut area 

(loc. 123) and Xancus cf. X. validus in the Emperador 

of Madden basin (loc. Yl). Both also are listed in the 

tables for the La Boca proper.

ALHAJUELA FORMATION

The few species from the early Miocene Alhajuela 

formation and the occurrence of the same or related 

species elsewhere and in other Canal Zone formations 

are listed in the following tables.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALI/EIDAE 461

Pelecypods (Arcidae to Pinnidae) from Alhajuela formation

Area imbricata 

Bruguiere.. __.__.___

Anadara (Rasia) 

dariensis dariensis 

(Brown and 

Pilsbry)? .--

Anadara (Rasia) cf. A. 

fissicosta (Spleker) 1 ..

Anadara (Tosarca) cf. 

A. tectumcolumbae

Olycymeris (Tucetona) 

sp.1 .

Olycymeris (Tucetona) 

pectinata canalis 

Brown and 

Pllsbry)?..... ......

Mytttus canoasensis 

Mali Ferreira and 

Ovinha.

Atrina? sp.1 ...........

Localities

Lower member

76

R

77 79

R

82

R 

sp.R

82a

R

84a

R

Upper member

85

R

C

R

85a

R

86

R

87

R

89

R

90a

R

R

R

1 Not described.

GATUN FORMATION

The distribution table for the middle Miocene Gatun 

formation on pages 462, 463 lists 55 species. Four 

of the gastropods, however, are already recorded in 

preceding chapters and one of the pelecypods is not 

described. (See footnotes at end of table.) This leaves 

a net addition of 50 described species to the 289 covered 

in earlier chapters.

Bailya crossata is the first Tertiary species of the 

genus from the Caribbean region and the earliest now 

known. An unfortunately incomplete, bizarre gastropod

Pelecypods from Alhajuela formation and occurrence elsewhere 

and in other Canal Zone formations of same or related species

Species from Alhajuela formation

Area imbricata Bruguiere.

Anadara (Rasia) dariensis 

dariensis (Brown and Pilsbry)?

Anadara (Rasia) cf. A. fissicosta (Spieker).

Anadara (Tosarca) cf. A, 

tectumcolumbae (Maury).

Glycymeris (Tucetona) pectinata 

canalis (Brown and Pilsbry)?

Mytilus canoasensis vidali 

Ferreira and Cunha.

Occurrence elsewhere and in other Canal 

Zone formations of same or related species.

Late Oligocene to Holocene. 

Also Gatun formation.

A. dariensis dariensis 

(Brown and Pilsbry), 

Gatun formation. For distribution see table for 

Culebra formation.

A. fissicosta (Spieker), Gatun 

formation; early Miocene, 

Peru.

A. tectumcolumbae (Maury), 

late Miocene, Trinidad.

G. pectinata canalis Brown 

and Pilsbry, Gatun formation. For distribution see 

table for Gatun formation.

Early Miocene, Brasil; middle (?) Miocene, Venezuela. 

Also Culebra, La Boca, 

and Gatun formations.

is described as xancid?, genus?. Any suggestions concerning its affinities would be welcomed.

The Gatun fossils include 13 of the 24 species of 

Anadara and half of the 12 species of the subgenus 

Rasia of that genus. Anadara veatchi, a species of the 

subgenus Tosarca, is the earliest member of a lineage 

that culminates in Anadara hypJialopilema now living 

in eastern Pacific waters. Potiarca, as a subgenus of 

Anadara, is adopted for many American species heretofore assigned to the subgenus Cunearca, including 

Anadara chavezi of the Gatun fauna. Cunearca itself, 

however, is represented by a Gatun species.
462 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Gastropods, scaphopods, and pelecypods

Gastropods:

Melongena cf. M. propatula Anderson

Bcaphopods:

Pelecypods:

Localities

Lower part

 ^< 

co

?R

3

R

R

?C

C

C3 

§

R

F

?R

R

C

R

s

R

A

R

?R

C

F

5co

--

R

R 

R

R

R

8

A

R

C

A

C

R

I

A

F

R

C

C 

F 

R

C

R

R

1

R

F

R 

R

R

|

R

F

r

A

\

C

R

A

A

A

A

R

r,

R

C

p

i

C

r,

R

A

A

F

A

R

F

1

R

R

R

R

F

R

--

--

F 

R

R

38

R

R

R

C

C

F

C 

R

F

$

F

C 

R

F

--

Middle part

Eastern area

8

?R

sp.C

,

 -

I

A

fl

A 

F

A

R

C

R

--

F

R,

1

R

A

R

A

R

A

A

R

R

F

"(

1

F

C

R

--

R

1

R

R

C

R

A

--

R,

1

R

C

R

F

--

bfi

3

R

fl

C

C

F

--

R,

" >,

H,

§

R

R

-

(N *

R

--

5

sp.R

5

R

R

sp.F

1

sp.R

1

R

--

1

--

R,

9

R

--

5?

R

A

r

R

R

F

--

R,

5!

R

--

--

-

1 Recorded on p. 81 as Trochita trochiformis (Born).

2 Recorded on p. 220 as Typhis (Pilsbrytyphis) gabbi Brown and Pilsbry. 

s Recorded on p. 286 as Xancus salidus salidus (Sowerby)?.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCTJLIDAE TO MALLEIDAE 

(Nuculidae to Isognomonidae) from Gatun formation

463

Localities Continued

Middle part Continued

Eastern area Continued

e

s

c

A

A

A

A

A

R

sp.R

R

F

g *

F

--

R

1

-

R

§

F

R

§

C

A

R

R

C

§

R

F

A

A

C

r,

c

R

R

1

R

A

A

C

C

§

R

--

--

1

F

--

C

IQ

R

F

C

3

--

R

R

--

C

S3

R

R

F

CS

R

R

R

C

to to

R

R

F

R

C

R

R

F

F

F 

R

R

1

R

R

R

F

F

>o

c

R

C

C

gIO

A

C

R

R

t~ >o

R

F

R

F

r,

R

c

S

F

R

1

F

--

i

R

R

C

0

F

R

Western area

S

r,

-----

F

R

5

--

R

1

R

F

R

R

to

C

R

R

C

F

F

CS

to

R

R

R

A

,0

to

F

o

to

A

F

R

A

A

 d 

to

R

R

F

9

F

R

1

R

F

F

s

F

R

R

8

R

8

0

R

C

R

F

R

R

F

A

R

8

R

R

R

R

CS

8

R

?R

r

A

Upper part

Eastern area

8

F

F

!> 

R

R

R

R

R

S

R

T?

R

R

F

S

R

R

R

R

R

r,

e

r

R

--

S

R

R

R

S

C

F

R

R

R

C 

R

F

g

F

--

C3

S

R

R

R

R

F

p;

t- ^

--

R

A

r

F

e!> 

R

F

R

A

R

R

C

R,

R

o

r

R

R

R

g

R

?R

&

R

R,

-

fi

1

R

(

R

R.

R

--

Western are

58

R,

F

if

rt P <

00

1

., t

1

B (

R C

Rl

1 0

R,

\

^

I R 

3 R

---

4 Recorded on p. 286 as Xancus validm fakonemis H. K. Hodson. 

* Not described.
464 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Three battered and worn valves of Anadara, subgenus 

Grandiarca, were collected at locality 170. They were 

transported and buried some distance from their habitat, probably a brackish-water habitat, or were reworked 

from older strata. One represents a distinctive species: 

Anadara dolaticosta. The other two, identified as Anadara grandis patricia?, are allied to the large eastern 

Pacific type of Grandiarca, Anadara grandis. The Miocene and Pliocene allies of that species in the Caribbean

region are reviewed and divided into a brackish-water 

group and a marine group. My acceptance many years 

ago of an alleged type (lectotype) of Sowerby's Area 

patricia is repudiated, as was done, also many years ago, 

by Rutsch.

Six of the 36 unequivocally identified species and 

subspecies are endemic. The occurrence elsewhere of the 

other 30 is shown in the following table.

Occurrence elsewhere of mollusks from Gatun formation

Gastropods: 

Crucibulum (Crucibulum) spinosum (Sowerby) .......

Engina turbineUa (Kiener) ____________ _ ...

Xancus dodonaius praelaevigatus (E. H. Vokes) ........

Scaphopods: 

Dentalium (Dentalium) armttlatum armillatum Toula... 

Dentalium (Tesseracme) dissimile Guppy .

Dentalium (Laevidentalium) pyrum Pilsbry and Sharp.. 

Cadulus (GadUopsis) dentalinus (Guppy)

Cadulus (Platyschides) bushii Dall .. .

Pelecypods: 

Nucula (Nucula) tenuisculpta Gabb ..................

AcUa (Acila) isthmica isthmica (Brown and Pilsbry). .

Saccella acrita epacra Woodring, n. subsp __ _ _

Saccella balboae (Brown and Pilsbry)

Area imbrtcata Bruguiere _ .. ...

Calloarca (Taeniacra) cachla Olsson .

Acar domingensis (Lamarck) . ........

Anadara (Rasia) dariensis dariensis (Brown and Pilsbry) 

Anadara (Rasia) actinophora actinophora (Dall) .

Anadara (Rasia) lienosa trochala Woodring, n. subsp. . - .

Anadara (Tosarca) veatchi veatchi (Olsson)

Anadara (Grandiarca) dolaticosta (Pilsbry and Johnson.. 

Anadara (Potiarca) chavezi (Engerrand and Urbina) ... 

Noetia (Noetia) reversa macdonaldi (Dall) ___ .

Glycymeris (Glycymeris) carbasina Brown and Pilsbry . 

Glycymeris (Tucetona) epacra Woodring n. sp

Glycymeris (Tucetona) pectinata canalis Brown and 

Pilsbry............................... .

Mytdus canoasensis vidali Ferreira and Cunha

Crenella divaricata (d'Orbigny)

Gatun formation

Lower part

X 

X

X

X 

X

X

X 

X 

X

X 

X 

X

X

Middle part

X 

X

X 

X 

X

X 

X

X 

X

X 

X 

X

X 

X 

X 

X

X

X

Upper part,eastern ara

X

X 

X 

X

X

X

X 

X

X

X

X 

X

X

Upper part,western ara

X

X

X

X

X

X 

X

Late *Oligocene 

X

Miocene 2Early 

X

X

X

X

Middle Miocene

Southeastern 

Costa Rica3

X

X

X

X

X 

X 

X

Northwestern Colombia 4

X

X 

X 

X

Cercado formaDominican tion, 

Republic

X

X

X

X

Gurabo formaDominican tion, 

Republic

X

X

X

X

Bowden forma- tion, Jamaica

X

X

X

X

Other 5

X

X

X 

X

X 

X 

X 

X

X 

X

X

X

Late Miocene

Limon foration, Costa Rica 

X

X 

X 

X

X

I

o

X

X

Early Pliocene 8

X

X

X

X

Late Pliocene 9

X

X

Holocene

X 

X

X

X

X

X

1 San Sebastian formation, Puerto Rico.

2 Las Perdices shale and deposits of early Miocene age in Rfo San Juan-Rio Sinfi 

area, Colombia; Thomonde formation, Haiti; Ayam6n limestone and Ponce limestone, Puerto Rico; Pirabas formation, Brasil; Tampa limestone and Chipola formation, Florida; lower part of Zorritos formation, Peru.

3 Lower part of Olsson's Gatun formation.

4 Hibachero. Piojo, and TubarS formations.

5 D eppsits of middle Miocene age in Bocas del Toro, Chiriqui, and Darien Provinces, 

Panama; Cantaure formation, other deposits of middle Miocene age, and middle(?) 

Miocene part of Santa Ynfis group, Venezuela; middle Miocene part of Brasso formaIn marked contrast to the gastropods, no genus or 

subgenus in the scaphopod and pelecypod fauna of the 

Gatun formation so far covered is extinct. The following subgenera, however, are paciphiles; that is, they 

formerly lived in the Caribbean region, but now are 

extinct there and survive in the eastern Pacific Ocean.

Padphile subgenera in fauna of Gatun formation 

Tesseracme (subgenus of Dentalmm) 

Tosarca 1 (subgenus of Anadara). 

Grandiarca* (subgenus of Anadara) 

Noetia s.s.

1 Occurs also in La Boca and Alhajuela formations.

2 Occurs also in Culebra and La Boca formations.

tion, Trinidad; Agueguexquite formation and other deposits of middle Miocene 

age in Tehuantepec area and Chiapas, Mexico; Shoal River formation and Oak Grove 

sand member, Florida; Angostura and Daule formations, Ecuador; upper part of 

Zorritos formation, Cardalitos, and Montera formations, Peru.

« Upper part of Olsson's Gatun formation.

f Usiacuri formation, Colombia; Esmeraldas formation, Ecuador.

8 Playa Grande and Mare formations, Venezuela; Matura formation and Courbaril 

member of Morne 1'Enfer formation, Trinidad; Caloosahatchee formation, Florida.

9 Mofn formation, Costa Rica.

A few paciphiles, listed below, are at the species level: 

Padphile species in fauna of Gatun formation

Crucibulum (Crucibulum) spinosum (Sowerby) 

Dentalium (Episiphon) innumerable elassum Woodring,

n. subsp.

Saccella acrita epacra Woodring, n. subsp. 

Anadara (Grandiarca) grandis patricia (Sowerby)? 

Noetia (Noetia) reversa macdonaldi (Dall) 

Crenella ecudoriana santiaya Olsson

Botula fusca, which is doubtfully recorded from the 

La Boca formation, survives on both sides of the Panama 

land bridge.

One Bohio species and four Gatun species are more 

closely related to living eastern Pacific species than to
GASTROPODS, SCAPH'OPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 465

any known to be living in the western Atlantic Ocean. 

They are as follows:

Species from Bohio and Gatun formations more closely related to 

living eastern Pacific species than to any known to be Jiving in the 

western Atlantic Ocean

Fossil species

Species from Bohio formation:

Adrana stena Woodring, n. sp. 

Species from Gatun formation: 

Nucula (Nucula) cf. N. cahuitensis

Olsson 

Saccella balboae (Brown and

Pilsbry) 

Anadara (Rasia) dariensis

dariensis (Brown and Pilsbry) 

Anadara (Rasia) cf. A. emarginata (Sowerby)

Living eastern Pacific species

A. crenifera (Sowerby) 

N. exigua Sowerby 

S. fastigata (Keen) 

A. concinna (Sowerby) 

A. emarginata (Sowerby)

CHAGRES SANDSTONE, INCLUDING TORO 

LIMESTONE MEMBER

Mollusks from the Chagres sandstone proper covered 

in the present chapter are listed in the following table.

Scaphopod and pelecypods (Nuculidae to Pinnidae) from the 

Chagres sandstone proper

Scaphopod:

Dentalium (Fissidentalium) granadanum esmeraldum 

Olsson____ _ ____

Pelecypods:

Acila (Acila) isthmica isthmica 

(Brown and Pilsbry)

Saccella cf. S. ornata 

(d'Orbigny) _______

Anadara (Rasia) 

honensis adiaphora 

Woodring, n. 

subsp______ _ ___

Glycymeris (Tucetona) secticostata 

schencki Nicol __ _

Atrina (Servatrina) 

aff. A. serrata

Localities

198

R

202

R

203

R

206

R

F 

F

R,

206a

sp.R

206b

F

?sp.

208

c

F 

C

The occurrence elsewhere and in other Canal Zone 

formations of the same or related form is as follows:

Mollusks from Chagres sandstone proper and occurrence elsewhere 

and in other Canal Zone formations of same or related form

Species from Chagres sandstone proper

Scaphopod: 

Dentalium (Fissidentalium)

granadanum esmeraldum

Olsson 

Pelecypods: 

Acila (Acila) isthmica

isthmica (Brown and

Pilsbry) 

Saccella cf. S. ornata (d'

Orbigny) 

Anadara (Rasia) honensis

adiaphora Woodring, n.

subsp.

Glycymeris (Tucetona) secticostata schencki Nicol 

Atrina (Servatrina) aff. A.

serrata (Sowerby)

Occurrence elsewhere and in other Canal 

Zone formations of same or related form

Esmeraldas formation, late 

Miocene, Eucador.

Also Caimito, La Boca, and 

Gatun formations.

S. ornata (d'Orbigny), late 

Miocene to Holocene.

A. honensis honensis (Olsson), 

middle Miocene, Costa 

Rica, Jamaica.

Also La Boca and Gatun 

formations.

A. serrata (Sowerby), Holocene. Also Gatun formation.

Unidentifiable molds of Anadara, subgenera Rasia 

and Potiarca, and of Glycymeris, subgenus Tucetona, 

were collected from the Toro limestone member.

DESCRIPTION OF TERTIARY MOLLUSKS 

CONTINUED FROM CHAPTER D

GASTROPODS CONTINUED FROM CHAPTER D

Additions and corrections to families covered in preceding chapters: Twenty-six of the 35 gastropods described in the present chapter are in collections from 

the Gatuncillo, La Boca, and Gatun formations acquired 

since publication of chapter B. One is an overlooked 

species from the marine member of the Bohio (?) formation. The other eight were recorded in preceding 

chapters, but additional data, including corrections, are 

presented for them. The page citations in headings refer 

to preceding chapters.

Family NERITIDAE (p. 66) 

Subfamily NEBJTINAE (p. 66)

The collection from the Gatuncillo formation at locality 23b, on Eio Palenque, contains four species of 

neritids, an unusual number for an Eocene formation 

in the Caribbean region.

Genus Nerita Linne

Linne, Systema naturae, 10th ed., p. 776, 1758.

Type (logotype, Montfort, Conchyliologie systematique, v. 2, p.

347, 1810) : Nerita peloronta LinnS, living, Florida to

Trinidad.

This ancient genus is not common in the Tertiary 

Caribbean province. Three Paleocene species, two

475-796 O - 73 - 2
466 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Eocene, a Miocene, a Pliocene, and two of doubtful Pliocene age are on record. Opercula are unknown.

Subgenus?

Nerita listrota Woodring, n. sp. 

Plate 69, figures 11,12,17

Of medium size, moderately thick-shelled, practically 

flat-topped. Color, where not bleached, dark brown. 

Upper edge of early half of body whorl angulated, 

angulation progressively subdued on late half. Sculpture coarse, consisting of weakly, or obscurely, noded, 

closely spaced, spiral bands of varying width, that at 

angulation widest. Growth threads strong, or fairly 

strong. Outer lip thin, scalloped, short lirae within aperture. Columellar lip dentate: a wide, moderately strong, 

basal denticle, followed by five narrow, short denticles, 

and a strong, unequally bifid upper denticle. Callus 

sparsely papillate near columellar lip: two papillae distinct, two others obscure. Callus thick near lower border.

Height 15 mm, diameter 19 mm (type).

Type: USNM 646646.

Type locality: 23b (USGS 24553, Upper course of 

Rio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama). Gatuncillo formation.

The outline and sculptural pattern of Nerita listrota, 

represented only by the type, suggest alliance with 

N. gramdosa Deshayes (Cossmann and Pissarro, 1910- 

13, pi. 5, figs. 38-3), a late Eocene species from the 

Paris basin. The callus of the Panama species is thicker 

and not rugose, and the spiral bands are more closely 

spaced. In outline and sculpture N. listrota resembles 

also N. planospira Anton (Martens, 1887-89, p. 23, pi. 4, 

figs. 4-7, 1887), living in the western Pacific Ocean. 

The nonascending outer lip of N. listrota, thicker callus, 

small central denticles on the columellar lip, and the 

absence of two channels at the upper edge of the callus 

show that the two species are not allied. No similar 

fossil or living American species is known.

Occurrence: Gatuncillo formation (late Eocene), locality 23b.

Subgenus?

Nerita hadra Woodring, n. sp. 

Plate 67, figures 1, 2, 6-8,11,12

Small, moderately thick-shelled, practically flattopped. Overall color pattern generally spirally maculated. Sculpture fine, subdued, consisting of low, narrow, crowded, spiral threads, at intervals a thread wider 

than others. Threads generally colored with light 

brown, elongate rectangles or squares, longest rectangles on widest threads. On early three-quarters of body

whorl of one specimen color absent on some spiral strips 

and solid on others. Outer lip thin, short lirae within 

aperture, except on largest shell (type). Columellar 

lip weakly dentate: a weak basal denticle, followed by 

little denticles, and a conspicuous, slender, upper denticle. Callus very thick for size of shell, especially lower 

part.

Height 8 mm, diameter (not quite complete) 10.5 

mm (type).

Type: USNM 646647.

Type locality: Same as preceding species.

Twenty-one specimens of this small species were collected at locality 23b. The assignment to Nerita is based 

on the lirate outer lip and the thick callus. To be sure, 

the type, the largest specimen, shows no lirae. Though 

its outer lip is broken, the part where lirae appear on 

smaller specimens, two of which are shown on plate 67, 

figures 1, 2, 7, 8, is intact. On the aberrantly colored 

specimen (pi. 67, figs. 7, 8) the change in pattern takes 

place abruptly.

No comparable species are recognized.

Occurrence: Gatuncillo formation (late Eocene), locality 23b.

Subgenus Nerita s.s.?

Nerita (Nerita?) species

Plate 73, figures 5, 6

Small, thick-shelled, practically flat-topped. Color 

pattern bleached, spiral bands light-colored and spaces 

between them dark-colored. Spiral bands relatively 

widely spaced, obscurely noded where not worn. Interior of outer lip denticulate. Columellar lip denticulate, 

size and arrangement of denticles obscured by calcareous crust. Surface of callus not well preserved.

Height 10.5 mm, diameter 11.2 mm (figured 

specimen).

Seven specimens of this unnamed species, all found 

in the La Boca formation at locality 116a, range in 

diameter from 4.5 to 11.2 mm. The illustrated shell, 

much of which is worn, is the only one on which the 

aperture can be exposed safely.

The spire is lower than that of the living American 

species and their fossil allies, and the spiral bands are 

not as closely spaced.

Occurrence: La Boca formation (early Miocene), 

locality 116a.

Genus Neritina Lamarck (p. 67)

Though 13 species of Neritina from the Tertiary 

Caribbean province have been described, the operculum 

of N. ectypha is the first to be found; in fact, the first 

in America.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCTJLIDAE TO MALLEIDAE 467

Subgenus?

Meritina ectypha Woodring, n. sp. 

Plate 67, figures 3-5, 9, 10, 14, 15

Very small, globose, spire very low. Prevailing color 

pattern consisting of brown, hair-like, closely spaced, 

wavy, axial lines on light-colored background. Irregular brown blotches generally superimposed on lines on 

parts of shell. At middle of shell light-colored band 

bearing widely spaced, looped, fine lines, convex toward 

outer lip, and similar, generally narrower, band on lower part of shell present or absent. Hair-like lines absent 

on an aberrant specimen, colored by three maculated 

spiral bands and widely spaced, coarse, axial lines between uppermost band and suture. Columellar lip weakly denticulate, uppermost denticle most distinct. Callus 

thick, bulging, outer edge sharply limited. Operculum 

light brown, peg moderately slender, rib slender and 

strongly arched.

Height 6.4 mm, diameter 7.1 mm (type).

Type: USNM 646650.

Type locality: 23b (USGS 24553, Upper course of 

Kio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama) Gatuncillo formation.

This very small species is represented by 19 specimens. The thick, bulging callus and hair-like color 

pattern are noteworthy. The aberrantly colored shell 

is shown on plate 67, figures 5, 10. The operculum (pi. 

67, fig. 9) was extracted from the shell illustrated on 

plate 67, figures 3, 4). During extraction it was slightly 

nicked and after the drawing was made, part of the peg 

was broken.

Occurrences: Gatuncillo formation (late Eocene), 

locality 23a.

Subgenus?

Neritina species

Plate 69, figures 21, 22

Small, globose, thick-shelled, spire very low. Color 

pattern consisting of spirally arranged, colorless crude 

rectangles, or more rounded eyes, on a brown background. Spiral arrangement interrupted by a few irregularly shaped colorless blotches. Columellar lip 

corroded. Callus moderately thick, slightly bulging, 

partly corroded.

Height 10.2 mm, diameter 10.9 mm (figured 

specimen).

Though this may be a new species, the apertural face 

of the single specimen is badly corroded.

Occurrence: Gatuncillo formation (late Eocene), locality 23b.

Family VITRIWELLIDAE (p. 69)

Genus Teinostoma H. and A. Adams (p. 69)

Subgenus Idioraphe Pilsbry (p. 69)

The earliest species of Idioraphe, Teinostoma prenanum Wade (Sohl, 1960, p. 62, pi. 6, figs. 9,10) is of Late 

Cretaceous (late Campanian) age. The following is 

the first of pre-Mioceiie age from the Caribbean region.

Teinostoma (Idioraphe) elachistum Woodring, n. sp. 

Plate 70, figures 3, 9, 10

Minute, moderately thick-shelled to thin-shelled, depressed dome-shaped. Periphery narrowly rounded. 

Body whorl partly enveloping spire, which is more or 

less covered with glaze of enamel. Faint spiral striae 

visible on some shells. Umbilical and parietal callus 

coalesced.

Height 0.6 mm, diameter 1.3 mm (type).

Type: USNM 646654.

Type locality: 23b (USGS 24553, Upper course of 

Rio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama), Gatuncillo formation.

Teinostoma elachistum is most similar to T. harrisi 

(Palmer, 1937, p. 47, pi. 2, figs. 27, 28; middle Eocene, 

Virginia), but is smaller and more compressed. It is 

smaller also than T. verrilli Meyer (Palmer, in Harris 

and Palmer, 1946-47, p. 222, pi. 28, figs. 2, 4, 1947; late 

Eocene, Mississippi). That species, however, is more 

compressed.

Thirty-five specimens of this minute teinostome were 

collected at locality 23b. The glaze of a thin translucent 

shell is so thin that it does not conceal the spire.

Occurrence: Gatuncillo formation (late Eocene), locality 23b.

Family TURRITELLIDAE (p. 97)

Genus Turritella Lamarck (p. 97)

Turritella collazica Maury

Plate 71, figure 18

Turritella collazica Maury, New York Acad. Sci., Scientific Survey of Porto Rico and Virgin Islands, v. 3, pt. 1, p. 51, pi. 

8, fig. 5,1920 (Oligocene, Puerto Rico).

Turritella cf. T. collazica Maury, Woodring, this report, p. 98, 

pi. 16, fig. 13, 1957 (Miocene, Canal Zone).

Large, apical angle wide. Whorl profile concave, 

dominated by basal carina. Basal carina somewhat undulated on best preserved specimen, tripartate: wide 

lower and upper parts and narrow middle part on best 

preserved specimen; more equally tripartate on another. 

Weak coarse spiral sculpture apparent on remainder of 

whorl. Base missing. Growth lines obscure, sinus apparently shallow and growth-line angle narrow.
468 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Height (3 whorls) 35 mm (estimated restored height 

TO mm), diameter 23 mm (figured specimen). Height (4 

whorls) 54 mm (estimated restored height 80 mm), 

diameter 29 mm (largest specimen).

Type: Am. Mus. Nat. Hist. 22556.

Type locality: Eio Collazo near San Sebastian, San 

Sebastian quadrangle, Puerto Rico, San Sebastian 

formation.

When chapter A was prepared, the crushed mold 

from the Emperador limestone member of the La Boca 

formation, identified as Turritella cf. T. collazica, was 

the only specimen in the Canal Zone collections. Two 

others from the La Boca proper are now available. The 

shell of that illustrated is replaced by calcite. The other, 

the large specimen mentioned on p. 431, is in poor condition.

Maury's type, which is not well represented by her 

drawing, is available through the kindness of Dr. N. D. 

Newell. It is a crushed mold, but shows more features 

than the Emperador mold. The whorl profile is more 

concave than indicated in the drawing. The basal carina 

is weakly bipartate and the sculpture above the carina is 

weaker and coarser than in the drawing.

As noted by Maury, T. collazica has no allies in the 

Caribbean region. Unequivocal allies elsewhere are not 

recognized.

Occurrence: La Boca formation (early Miocene), 

localities lOOb, 116a. Emperador limestone member of 

La Boca formation (early Miocene), locality 123. San 

Sebastian formation (late Oligocene), Puerto Rico.

Turritella subgrundifera Ball 

Plate 74, figure 1

Turritella subgrundifera Ball, Wagner Free Inst. Sci. Trans., v.

3, pt. 2, p. 313, pi. 22, fig. 23, 1892 (Miocene, Florida).

Pilsbry and Brown, Acad. Nat. Sci. Philadelphia Proc., v.

69, p. 35, 1917 (Miocene, Colombia). Merriam, California

Univ. Dept. Geol. Sci. Bull., v. 26, no. 1, p. 48, pi. 29, figs. 8",

9,1941 (Miocene, Florida). Gardner, U.S. Geol. Survey Prof.

Paper 142, p. 590, pi. 57, fig. 1, 1944 (Miocene, Florida).

Gardner, Geol. Soc. Am. Mem. 11, p. 153, 1945 (Miocene,

Mexico). 

Turritella cf. T. subgrundifera Ball, Woodring, this report, p.

105, pi. 16, fig. 3,1957 (Miocene, Canal Zone).

Height (incomplete) 32.2 mm, diameter 13.6 mm 

(figured specimen).

Type :USNM 113437.

Type locality: USGS 2214, Ten Mile Creek, 1 mile 

west of Baileys Ferry, Calhoun County, Florida, 

Chipola formation.

On the basis of seven additional specimens collected 

at locality lOlh, the slender carinate Turritella in the 

La Boca formation is unequivocally identified as T. 

subgnmdifera. Though the development of the sculpture 

and the growth line are still unknown, in size, apical

angle, whorl profile, including the carina near the base, 

and strength and spacing of spiral threads, the best of 

the La Boca fossils closely resemble those from the 

Chipola formation of Florida.

Merriam (1941, p. 48) pointed out that T. subgnmdifera is an early species of his T. ocoyana stock. It is a 

relatively small, slender, early ally of T. abrupta (p. 

106, 430) and the Californian T. ocoyana.

Occurrence: La Boca formation (early Miocene) localities 99d, lOlh. Miocene, Colombia (Brown and 

Pilsbry's record). Guajalote formation (early Miocene), northeastern Mexico. Chipola formation (early 

Miocene) and Oak Grove sand member of Shoal River 

formation (middle Miocene), Florida.

Family PSETJDOMELANIIDAE 

Genus Bayania Munier-Ghalmas

Munier-Chalmas, in Fischer, Manuel de conchyliologie, p. 698,

1885. 

Type (orthotype) : Melania lactea Lamarck, Eocene, Paris basin.

Bayania epelys Woodring, n. sp. 

Plate 68, figures 5, 6,11,12

Wayania sp., Trechmann, Geol. Mag., v. 62, p. 496, pi. 24, fig. 

2,1925 (Eocene, Barbados).

Large for the genus, moderately inflated, thickshelled or moderately thick-shelled, spire whorls almost 

flat-sided. Protoconch and earliest post-protoconch 

whorls almost flat-sided. Protoconch and earliest postprotoconch whorls not preserved. Whorls generally 

smooth; exceptionally upper part of mature body whorl 

or lower part of immature body whorl showing faint, 

coarse, spiral sculpture. Growth lines slightly arcuate on 

spire whorls and upper part of body whorl. Basal lip 

slightly patulous. Parietal callus fairly thick.

Height (incomplete) 26.7 mm (estimated restored 

height 31 mm), diameter 11.3 mm (type).

Type: USNM 646655; paratypes USNM 646656, 

646657,

Type locality: 23b (USGS 24553, Upper course of 

Eio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama), Gatuncillo formation.

Complete outer and basal lips are not preserved on 

any of the 36 specimens, repersenting growth stages 

from a height of 7 to 26.7 mm (estimated 8.5 to 31). The 

outline of the outer lip, however, is shown by the growth 

lines and the basal lip is preserved on two, one of which 

is illustrated (pi. 68, fig. 11). The type is the largest 

specimen, but a paratype (pi. 68, fig. 12) is in better 

condition.

The earliest preserved whorls are at a growth stage 

at which Bayania lactea, the early to late Eocene type 

of the genus, bears axial and spiral sculpture, which 

later disappears. The growth lines of B. epelys, and
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NTJCULIDAE TO MALLEIDAE 469

therefore the outer lip, are slightly more arcuate than 

that of B. lactea. Despite these differences, the two 

species have basically similar features, including a 

slightly patulous basal lip. The middle Eocene American B. secalis (Lea) (Palmer, 1937, p. 184, pi. 21, figs. 

18-20, 24) is much smaller (height 9 mm) and more 

slender. Like B. epelys, its early whorls lack axial and 

spiral sculpture. Trechmann's unnamed middle Eocene 

Bayania from Barbados may possibly be B. epelys.

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b. Scotland group (middle Eocene), Barbados 

(identification doubtful).

Family FSETJDOMELANIIDAE?

Genus Charadreon Woodring, n. gen.

Type: Charadreon leptus Woodring, n. sp., Gatuncillo formation.

Small, slender to very slender. Spire whorls, except 

earliest few, practically flat-sided and slightly turreted. 

Early sculpture reticulate. Later sculpture consisting of 

axial ribs overriden by closely spaced spiral threads. 

Axial sculpture disappearing on intermediate whorls. 

Spiral sculpture continuing with undiminished strength 

or subdued on last few whorls. Outer lip, as shown by 

growth lines, sinuate, apex of wide, shallow sinus at 

upper third of whorl. Siphonal notch shallow. Siphonal 

fasciole slightly inflated or not inflated, set off by low 

thread.

The family relations of Charadreon are uncertain. 

Though it is but a step from the patulous basal lip of 

Bayania to the shallow siphonal notch of Charadreon 

and from the arcuate outer lip of Bayania epelys to the 

sinuate lip of Charadreon, perhaps the notch and sinus 

are incompatible with assignment to the family Pseudomelaniidae. Whether Charadreon is related to the 

modern fresh-water thiarids is doubtful.

Charadreon leptus Woodring, n. sp. 

Plate 68, figures 1-4

Small, slender to very slender. Early post-protoconch 

whorls slightly bulging, other spire whorls practically 

flat-sided and slightly turreted. Body whorl slightly 

turreted. Protoconch blunt, 114 to 1%-whorled, end 

marked by gradual appearance of sculpture. Earliest 

sculpture reticulate, consisting of evenly spaced, fine, 

axial and spiral threads, absent on lower part of body 

whorl. At later stage axial threads transformed into 

more widely spaced ribs, and spiral threads into closely 

spaced, coarser threads overriding ribs. Axial ribs gradually disappearing at varying stage on intermediate 

whorls, generally last forming subdued nodes adjoining 

suture. Spiral threads persisting; on some shells fine, 

secondary threads between them, or subdued on last few 

whorls and so closely spaced that only a shallow stria

appears between them. Growth lines strongly arcuate 

on spire whorls, apex of arc little above middle of whorl. 

On body whorl forming a wide, shallow sinus, apex at 

upper third of whorl. Siphonal notch shallow. Siphonal 

fasciole slightly inflated or not inflated, set off by low 

thread. Parietal callus moderately thick.

Height (not quite complete) 18 mm, diameter 6.5 mm 

(type).

Type: USNM 646658; paratype USNM 646659.

Type locality: same as preceding species.

Charadreon leptus is extraordinarily abundant at 

locality 23b, where an estimated several thousand were 

collected. Some 50, including glassy specimens, are minute shells consisting of the protoconch, or the protoconch and one or two post-protoconch whorls. Among 

them are the only ones that have an undamaged outer 

lip, but they represent a stage before the sinus was 

formed. Of mature shells only the paratype has an undamaged siphonal notch.

As shown by the illustrations, this is a variable species 

in outline and sculpture. The disappearance of axial 

sculpture is invariable, but the stage at which it disappears is variable, and the strength and spacing of the 

spiral threads on late whorls are also variable. Moderately slender specimens mimic the Oligocene western 

European Bayania semidecussata (Lamarck) (Cossmann, 1909, p. 98, pi. 1, figs. 12-14) and very slender 

specimens mimic the middle Eocene western European 

B. bezanconi (Vasseur) (Cossman, 1899, p. 13, pi. 2, figs. 

11,12).

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Family THIARIDAE

Subfamily MELANOFSINAE

Genus Faunus Montfort

Montfort, Conchyliologie systelnatique, v. 2, p. 426,1810.

Type (orthotype) : Faunus melanopsis Montfort (=8trombus

ater Linn£), living, western Pacific islands and Australia,

at mouth of streams.

Faunus xenicus closely resembles F. ater not only in 

outline, practically smooth whorls, and apertural features, but even in closely spaced growth lines, which 

correspond to the lines marking darker color on shells 

of F. ater. It is more similar to F. ater than any of the 

Eocene European species that have been assigned to 

Faunus.

As pointed out by Olsson, Pseudofaunus bravoensis 

(Olsson, 1931, p. 86, pi. 15, figs. 9,11), a larger, thickshelled Oligocene Peruvian species that is the type of 

Pseudofaunus, is distinguished from Faunus chiefly by 

its strongly bulging siphonal fasciole. Its outer-lip 

sinus also is deeper, more symmetrical, and the apex is 

farther from the suture.
470 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Faunus xenicus Woodring, n. sp. 

Plate 69, figures 13, 14, 19

Moderately large, slender, spire whorls practically 

flat sided. Suture deeply incised. Mature body whorl set 

off by progressively widened sutural shelf, its outer edge 

swollen near outer lip. Earliest part of protoconch not 

preserved, remainder indistinguishable from early 

post-protoconch whorls. Sculpture limited to obscure 

spiral bands and threads, most distinct on lower part of 

body whorl, limited to that part on immature and some 

mature specimens; on others appearing on entire body 

whorl, or on that whorl and penult, or even antepenult. 

Growth lines closely spaced, asymmetrically arcuate on 

spire whorls, on body whorl forming wide, shallow, 

asymmetrical sinus, apex at upper fourth of whorl. 

Siphonal f asciole wide, flat, limited by low thread, bearing growth lines of wide, moderately deep, asymmetrical siphonal notch, apex near limiting low thread. 

Columellar lip thick.

Height (4 whorls) 37.5 mm (estimated restored 

height 55 mm), diameter (incomplete) 18 mm (type).

Type: USNM 646662; paratype 646663.

Type locality: Same as preceding species.

All of the 22 specimens are incomplete in fact, half 

of them consist of only a few whorls and none has 

undamaged apertural features. The closely spaced 

growth lines show that the outer-lip sinus is shallow. 

The growth lines on the siphonal fascicle, preserved on 

the type (pi. 69, fig. 14) and another specimen, reveal 

a moderately deep, asymmetrical siphonal notch. The 

f asciole itself is flat.

Faunus ater, the type of the genus, lacks a sutural 

shelf on mature body whorls, its suture is not as deeply 

incised, and the weak spiral sculpture on the base of 

the body whorl is more obscure.

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Family CERITHIIDAE (p. 170)

Subfamily POTAMIDINAE (p. 176)

Genus Potamides Brongniart (p. 176)

Potamides? micraulax Woodring, n. sp.

Plate 69, figures 4, 15, 16

Of medium size, slender, spire whorls flat sided. Low, 

wide varix on intermediate whorls of one specimen. 

Earliest preserved whorls sculptured with axial ribs 

overridden by closely spaced spiral threads. Ribs gradually disappearing. Sculpture of intermediate and late 

whorls consisting of flat spiral bands separated by narrow, vertical-sided channels. Base sculptured with 

narrow, more widely spaced bands. Outer lip, as shown 

by growth lines, widely sinuate, apex at middle of 

whorl. Siphonal notch wide, very shallow. Siphonal

fascicle flat, except a slight bulge near notch, limited by 

thread. Columellar lip thin.

Height (2+whorls) 20 mm (estimated restored 

height 38 mm), diameter (incomplete) 10.2 mm (type).

Type: USNM 646664; paratypes USNM 646665, 

646666.

Type locality: Same as preceding species.

The early sculpture is potamidine-like, but intermediate and late sculpture is like that of a sharply incised 

Telescopium. Though the outer lip, as shown by the 

growth lines, and wide, shallow siphonal notch are 

Potamides-lib&, typical Potamides lacks a siphonal fasciole. The fascicle is preserved only on the type. Its 

slight budge near the notch probably is an abnormality. The smaller paratype is the only one of the five 

specimens showing varices. All five are incomplete.

The sculpture of Morgania costata (Woods, 1922, p. 

83, pi. 9, figs. 7-10; Paleocene and Eocene, Peru) is 

similar, but the outline of the Peruvian species is 

pupoid.

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Genus Hannatoma Olsson (p. 68)

Hannatoma is classified as a potamidine cerithid, instead of as a thiarid. It is a unique genus without known 

close allies. It occurs in Eocene deposits in Peru, 

Panama, Colombia, and Venezuela, and in Oligocene in 

Peru. It is doubtful 'that it is a brackish-water genus.

Hannatoma antyx Woodring, n. sp. 

Plate 68, figures 9, 15,19, 20

Hannatoma? cf. H. emendorferi Olsson, Woodring, this report, 

p. 68, pi. 14, fig. 3,1957 (Eocene, Canal Zone).

Moderately large, moderately slender, thick-shelled, 

flat-whorled outlined modified by flange-like spiral 

cords, especially sutural cord. Protoconch slender, twowhorled, whorls inflated, end marked by gradual appearance of sculpture. Earliest two or three post-protoconch whorls oarinate below middle of whorl. Later 

early whorls evenly swollen. Earliest sculpture a carinaf orming spiral thread, followed immediately by a thread 

above oarina and later by other minor threads. Swollen, 

widely spaced axial ribs, overridden by spiral threads, 

appearing on third post-protooonch whorl and gradually disappearing on about tenth. As they disappear a 

sutural cord is strengthened and in few whorls dominates profile. Remaining whorls generally sculptured 

also with two generally flange-like cords, representing 

original carina-forming thread and later thread above 

it. On many specimens upper one reduced, exceptionally 

absent and lower cord almost as strong as sutural cord. 

Base of mature body whorl bearing three or four other 

widely spaced cords. Microscopic spiral sculpture on
GASTROPODS, SCAPHOPODS, PELBCYPODS: NTJCULIDAE TO MALLEIDAE 471

unworn surfaces. Growth lines strong, outlining outerlip wide, shallow sinus, apex between sutural cord and 

next lower cord. On fully mature specimens supplementary sinus on sutural cord of body whorl at resting 

stages marked by exaggerated growth lines. Siphonal 

notch wide, shallow, as shown by growth lines. Siphonal 

canal of moderate length, siphonal f asciole absent. Columellar lip thin.

Height (incomplete) 54.7 mm (estimated restored 

height 70 mm), diameter (almost complete) 20 mm 

(type).

Type: USNM 646667; paratype USNM 646668.

Type locality: Same as preceding species.

Hannatoma antyx, like Oharadreon leptus but on a 

smaller scale, is extraordinarily abundant at locality 

23b. Some 300 specimens, ranging in height from 4 to 

54.7 nun (estimated 70 mm), aore in the collection and 

perhaps an equal number, fragments of a whorl or two, 

were discarded. It is by far the largest collection of 

Hannatoma and the first collection to show the protoconch and the development of the sculpture. Of these 

hundreds, however, none has an undamaged aperture, 

not even any of the scores of very small specimens.

The type, which was damaged and repaired during 

growth, shows the prevailing sculptural pattern. The 

incomplete silicified specimen from the Rio Casaya area, 

described in chapter A, has only two subequal cords on a 

wihorl, like tihat shown on plate 68, figure 20. Disappearance of axial sculpture is shown on plate 68, figure 15.

The spiral cords are sharper and more flange-like 

than those of the other known species: H. emendorferi 

Olsson (1931, p. 82, pi. 15, figs. 3, 8; Eocene, Peru, Colombia, Venezuela), H. gesteri (Hanna and Israelsky) 

(Olsson, 1931, p. 81, pi. 16, figs. 2, 7; Oligocene, Peru), 

and H. tumbezia Olsson (1931, p. 82, pi. 15, figs. 1, 2; 

Oligocene, Peru).

Occurrence: Gatuncillo formation (middle and late 

Eocene), localities 23b, 38.

Genus Tympanotonos Schumaeher

Schumacher, Essai d'un nouveau systeme des habitations des 

vers testaces, p. 211,1817.

Type (monotype) : Tymponotonos fluviatills [fluviatilis] Schumacher ( =Murex fuscatus Linne), living, marshes at mouth 

of rivers, tropical west Africa.

The type species has been well illustrated by Pilsbry 

and Bequaert (1927, p. 246, pi. 20, figs. 1-9).

Tympanotonos acanthodes Woodring, n. sp. 

Plate 68, figures 8,10; plate 69, figures 23, 24

Large, slender, flat-whorled outline modified by 

spines near suture. Intermediate and some early whorls 

bearing a varix. Earliest preserved sculpture cerithoid, 

consisting of axial ribs, pinched off before reaching base

of spire whorls, overridden by three spiral threads, later 

converted into flat cords, narrowed between ribs. Later 

slightly undulated, narrower cord added at base of spire 

whorls. On intermediate and late whorls ribs progressively reduced between cords. Cord near suture progressively more swollen where ribs formerly intersected it, 

swellings eventually forming conspicuous spines. Other 

cords narrower and iioded, lower cord more closely 

noded than other two. Slightly noded secondary thread 

present or absent between those two. Microscopic spiral 

sculpture on unworn surfaces. Growth lines strong, 

exaggerated at intervals, outlining outer-lip wide, deep 

sinus, apex at about middle of spire whorls. Base bearing a strong cord near periphery, a lower cord below 

middle, and, at least on immature shells, microscopic 

spiral sculpture. Siphonal canal broken, siphonal notch 

shallow, according to growth lines. Siphonal fasciole 

slightly inflated, smooth, forming part of thick columellar lip. Columella of immature shells bearing a low 

median fold.

Height (3 whorls, siphonal canal broken) 36.5 mm 

(estimated restored height 75 mm), diameter (including spines) 27.5 mm (type).

Type: USNM 646671; paratypes USNM 646672, 

646673.

Type locality: Same as preceding species.

This species is represented by 21 specimens, all fragments of 2 to 10 whorls. As with many other gastropods 

from locality 23b, the outer lip and the end of the siphonal canal are missing on all. The type and two paratypes, however, are practically the equivalent of an 

entire mature shell and some of the apertural features 

are preserved on the type and immature shells. A columellar fold is not apparent on the type species. Whether 

it is present on mature shells of the Panama species is 

indeterminable.

Tympanotonos is rare in America. Trechmann recorded an unnamed early Eocene Jamaican species and 

one of middle Eocene age from Barbados (Trechmann, 

1924, p. 14, pi. 2, fig. 6; 1925, p. 495, pi. 24, fig. 5, respectively). The spines of the Jamaican species, represented by three topotypes in USNM collections (USGS 

18281, 21930), are blunter than those of T. acanthodes, 

and below the sutural cord spire whorls are sculptured 

with three coarsely noded cords and a fourth less noded 

cord at the base of whorls. According to the illustration, 

the Barbados species is not comparable to T. acanthodes.

T. lagunitensis Woods, 1922, p. 90, pi. 11, figs. 10-12; 

late Eocene, Peru) has been assigned to the endemic 

American genus Diplocyma (Pilsbry and Olsson, 1935, 

p. 11). Cossman (1906, p. 120) assigned Gerithium JiUlsboroensis Heilprin, an early Miocene Florida species, to 

Tympanotonos. It was placed under Potamides by Dall
472 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

(1890-1903, p. 286, pi. 15, fig. 12,1892) and is best left 

there, despite the low, blunt spines on the sutural cord. 

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Genus Harrisianella Olsson

Olsson, Bull. Am. Paleontology, v. 15, no. 57, p. 20, 1979. 

Type (orthotype) : Harrisicvnella peruviana Olsson, middle and 

late Eocene, Peru.

This curious Strioterebrum-\^k& cerithid genus is 

found in formations of middle and late Eocene age in 

Peru, in late Eocene deposits of eastern Colombia, and 

of the Tonosi area and Colon Province in Panama, and 

in a late Eocene formation in Texas.

Harrisianella camptica Woodring, n. sp. 

Plate 69, figures 3, 5-8

Of medium size, slender, whorls practically flat sided. 

Earliest whorls missing, earliest preserved whorls worn. 

Varix on early whorls of one specimen. Sculpture dominated by Strioterefirum-like, noded sutural cord. Nodes 

at first rectangular, later axially elongate and retractive. 

Eemainder of spire whorls and of body whorl above base 

sculptured with closely spaced, generally coarse axial 

ribs, alined with nodes on sutural cord and connected 

with them by slight swellings in groove setting off cord. 

Kibs and retractive nodes forming arc, outlining wide, 

moderately deep, outer-lip sinus, apex near sutural cord. 

Bibs abruptly terminated by deep groove at base of 

spire whorls and at periphery of body whorl. On three 

specimens ribs and nodes exceptionally narrow. Base 

sculptured with two strong upper, spiral threads and 

two weak lower ones. Siphonal canal apparently short, 

end not preserved. Lowermost preserved part of smooth 

siphonal fasciole set off by low thread, upper part 

merging into wide, thick columellar lip.

Height (almost complete) 31.6 mm, diameter (almost 

complete) 10 mm (type).

Type: USNM 646674; paratype USNM 646675.

Type locality: Same as preceding species.

Harrisianella camptica is based on 25 incomplete 

specimens. The early whorls and some later parts of the 

type and others are worn or corroded. Three fragments, 

one of which is illustrated (pi. 69, figs. 7, 8), have exceptionally narrow ribs and nodes, but there is no gradation between them and the prevailing coarser ribs.

The sutural-cord nodes and ribs form a stronger arc 

than that of H. peruviana Olsson (1929, p. 21, pi. 8, fig. 

7; middle and late Eocene, Peru), the type of the genus. 

In that respect H. campicta is similar to H. plicifera 

(Heilprin) (1880, p. 151, fig. 8; late Eocene, Texas), 

the only other described species of the genus. The ribs 

of that species, however, are wider, more closely spaced 

and disappear on the later part of the mature body

whorl. So far as sculpture is concerned, Heilprin's drawing is better than Aldrich's (1897, p. 4, pi. 3, fig. 2), but 

Aldrich's figure 2a adequately shows the lower part of 

the shell. His illustrations were reproduced by Palmer 

(in Harris and Palmer), 1946-47, p. 302, pi. 39, figs. 11, 

12,1947). My colleague Druid Wilson called my attention to a collection of some 20 specimens of H. plicifera 

from a well in Texas (USGS 11137, W. A. Everett No. 

1, Three Eivers, Live Oak County, depth unknown). 

They show a considerable range of variation in the width 

and spacing of ribs on immature whorls. None is as large 

as the largest of three in the type lot (USNM 8919).

H. camptica occurs also in the Bucaro formation of 

the Tonosi area in southwestern Panama: the species 

mentioned by Palmer (in Harris and Palmer, 1946-47, 

p.303,1947).

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b. Bucaro formation (late Eocene), Tonosi 

area, Panama (USGS 8286, 8414).

Subfamily CERITHHNAE (p. 170) 

Genus Bezanconia Bayle

Bayle, in Fischer, Manuel de conchyliologie, p. 680,1884. 

Type (monotype) : Cerithium spiratum Lamarck, middle 

Eocene, Paris basin.

This distinctive Eocene genus is rare in America. It 

has been found only in Jamaica, Panama, and Texas. 

At an early date Heilprin described the only Bezanconia 

from mainland North America as well as the only 

Harrisianella. His Fusus marnochi (Heilprin, 1880, 

p. 151, fig. 6; Aldrich, 1897, p. 5, pi. 3, figs. 4, 4a; late 

Eocene, Texas) is identified as an immature Bezanconia 

(type, USNM 8917).

Generic assignment of the Paleocene Peruvian 

cerithid described as Bezanconia pupoidea (Woods, 

1922, p. 89, pi. 11, figs. 6-8) is doubtful.

Bezanconia cosmeta Woodring, n. sp.

Plate 68, figures 14,16, 21

Of medium size, moderately slender to moderately inflated. Early whorls cerithoid, later whorls turreted, 

widely and deeply channeled adjoining suture. A varix, 

exceptionally two, on all whorls, except on a few earliest 

and mature body whorl; subdued on penult, or on penult 

and antepenult. Protoconch missing. Early sculpture 

like that of Tympanotonos acanthodes: axial ribs overridden by three spiral threads, later converted into 

cords and a narrow thread added at base of spire whorls. 

Kibs and later cords disappear at varying stage, exceptionally early on a few. Thread at base of spire 

whorls continuing, but subdued on some antepenult and 

later whorls. Immature base sculptured with spiral 

threads, uppermost two strongest, all generally subdued on mature shells. Microscopic spiral sculpture visi-
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 473

ble on unworn intermediate whorls. Growth lines forming shallow arc. Lirae or denticles on interior of some 

immature body whorls. Siphonal canal short. Siphonal 

notch apparently absent. Siphonal fasciole slightly inflated, smooth, on immature shells limited by overhanging shelf alined with columellar fold; on mature 

shells forming slightly inflated part of thick columellar 

lip. Mature columellar lip detached. Mature columellar 

fold weak, immature fold strong.

Height (incomplete) 41 mm (estimated restored 

height 51 mm), diameter (incomplete) 17 mm (type).

Type: USNM 646677; paratype USNM 646678.

Type locality: same as preceding species.

Twenty-eight specimens of this strongly sculptured 

Bezanconia were collected at locality 23b. Almost half 

of them, however, consist only of early whorls and another quarter are fragments of two or three whorls. 

As usual, the outer lip is broken on all. The type, a 

slender shell, has an undamaged mature columellar lip. 

Immature shells are distinguished from immature shells 

of Tympanotonous acanthodes by the consistent varices 

and stronger columellar fold of the Bezanconia, and by 

the internal lirae or denticles of at least some. No lirae 

or denticles are shown by an immature specimen of the 

type species, B. spirata, that has a height of 30 mm, the 

smallest available.

The strong early sculpture of B. cosmeta is unique. 

The earliest available whorls of B. spirata (diameter 

3 to 9 mm) are sculptured with fine spiral threads. As 

noted by Trechmann, B. woodsi (Trechmann, 1924, p. 

13, pi. 2, fig. 2; early Eocene, Jamaica), the only other 

known Caribbean species, is like a small version of B. 

spirata, but the channel adjoining the suture is narrower 

and shallower. The early whorls are missing on the 

type and a USNM topotype (USGS 18281).

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Family ARCHITECTONICIDAE (p. 163)

Genus Architectonica Roding (p. 163)

Submenus Architectonica s.s.

Architectonica (ArcMtectonica) cf. A. nobilis Roding, Woodring, 

this report, p. 165,1959 (Miocene, Canal Zone).

Architectonica (Architectonica) nobilis Roding, subspecies 

Plate 71, figures 4, 5,10,11

Moderately large, low-spired, umbilicus wide to moderately wide. Dorsal surface sculptured with four 

weakly noded cords, not including peripheral cord. 

Peripheral cord weakly noded. Ventral surface sculptured with narrow cord adjoining peripheral cord, 

coarsely noded umbilical cord, and wrinkles extending 

outward from umbilical cord.

Height 6.5 mm, diameter 13.5 mm (smaller figured 

specimen). Height (reduced by crushing) 8.5 mm, diameter 30.5 mm (larger figured specimen).

Despite replacement of shell material by calcite, 

among 25 specimens from the La Boca formation at 

locality lOlh and five at locality 116a, about half are 

in good enough condition to show that they are not 

ArcMtectonica nobilis nobilis, which ranges back to 

early Miocene time elsewhere in the Caribbean region 

(p. 167). The best preservation is shown by an immature 

specimen (pi. 71, figs. 4, .5, 11). The spire of the larger 

illustrated specimen is crushed and the dorsal sculpture 

is partly obliterated. The ventral sculpture is similar 

to that of the larger A. nobilis Tcarsteni (this report, 

p. 167, pi. 30, figs. 1-3; Chagres sandstone), but the 

umbilicus of that form is narrower.

Though this may be a new subspecies, no mature 

specimen is well enough preserved to serve as a namebearer.

The La Boca fossils (Culebra of chapter B, localities 

99b, 99c, 100, 116) recorded on page 165 as A. cf. A. 

nobilis presumably are the same as those from localities 

lOlh and 116a, but are unidentifiable as such.

Occurrence: La Boca formation (early Miocene), localities lOlh, 116a.

Family CALYPTRAEIDAE (p. 79)

Genus Calyptraea Lamarck (p. 80)

Calyptraea lispa Woodring, n. sp.

Plate 69, figures 1, 2,10

f'Calyptraea cf. C. aperta (Solander), Woodring, this report, p. 

80, 1957 (Eocene, Panama).

Of medium size, high-spired, base subcircular to elliptical. Early and intermediate whorls forming widebased cone, later part of mature body whorl shouldered. 

Suture distinct or indistinct. Protoconch consisting of 

iy2 to 1% capulid whorls, merging into first post- protoconch whorl. Growth lines strong. Diaphragm deeply 

sinuate at outer margin.

Height 9.5 mm, maximum diameter 19.2 mm (type). 

Height 2.3 mm, maximum diameter 5.5 mm (paratype).

Type: USNM 646680; paratype USNM 646681.

Type locality: 23b (USGS 24553, Upper course of 

Eio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama), Gatuncillo formation.

This species combines the outline of the widespread, 

long-ranging (Paleocene to Miocene) Oalyptraea 

aperta (Solander) (Cossmann and Pissarro, 1910-13, 

pi. 12, fig. 73-1), the lack of sculpture of O. levis 

Deshayes (1861-63, p. 276,1861; G. laevigata Deshayes, 

1824-37, p. 31, pi. 4, figs. 8-10, 1824, not O. laevigata 

Lamarck, 1822; Eocene, Paris basin) and other species,
474 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

and the deeply sinuate diaphragm of G. Idbellata 

Deshayes (1861-63, p. 277, pi. 9, figs. 5-7, 1861; Oligocene, Paris basin) and other species. In unsculptured 

surface and deeply sinuate diaphragm it is similar to 

C. centralis (Conrad), described on page 80, but the 

outline of that species is a smoothly tapering, low cone. 

The type is the largest of 15 specimens, two-thirds of 

which are immature, including the paratype, the only 

specimen that has an intact diaphragm. Though the 

limestone molds, described as G. cf. C. aperta, have the 

outline of G. lispa, their diaphragm is unknown.

Occurrence: Gatuncillo formation (late Eocene), localities 9, 12 (identification doubtful both localities), 

23b.

Genus Trochita Sch.umach.er (p. 80)

Trochita spirata Fortes?

Trochita trochiformis (Born), erroneous designation for T. 

radians (Lamarck), Woodring, this report, p. 81, pi. 19, 

figs. 11-14,1957 (Miocene, Panama).

After publication of chapter A, in a personal communication the late L. G. Hertlein, of the California 

Academy of Sciences, called my attention to Trochita 

spirata Forbes (1850 (1852), p. 271, pi. 11, fig. 1; living, 

Gulf of California; Keeve, 1859, species 8, pi. 2, figs. 8, 

8a), which was overlooked when the fossils from Panama were identified. At a later date Olsson and Petit 

(1964, p. 565) expressed the opinion that the Gatun species is more suggestive of T. spirata than of T. radians.

I am indebted to Dr. Hertlein for the loan of five 

specimens of T. spirata from the coast of the state of 

Michoacan, Mexico. The dark-colored interior a feature not available in fossils readily distinguishes that 

species from T. radians. In addition, however, the ribs 

are more widely spaced than those of T. radians. The 

ribs of the smaller Gatun specimen (pi. 19, figs. 11,12) 

are widely spaced, whereas those of the larger (pi. 19, 

figs. 13,14) are closely spaced. That is, the identification 

is equivocal.

The status of the middle Miocene Venezuelan fragment described as T. cf. T. radians (Jung, 1965, p. 497, 

pi. 66, figs. 1, 2) and of the early Pliocene Trinidad 

small specimens identified as T. radians (Jung, 1969, 

p. 473, pi. 47, figs. 12,13) is uncertain, but they evidently 

are not T. spirata. In any event the Trinidad form is the 

last western Atlantic Trochita.

Occurrence: Lower part of Gatun formation (middle 

Miocene), localities 136,136a.

Trochita species 

Plate 72, figures 12, 16, 19

Trochita? cf. T. trochiformis (Born), Woodring, this report, p. 

37 (list), 81 (mentioned without designation), 1957 (Miocene, Canal Zone).

Small, low-spired to moderately high-spired. Kibs of 

moderate width and height, closely spaced.

Height 12.5 mm, diameter 23.3 mm (figured specimen).

Some 40 specimens of Trochita from the La Boca 

formation at locality 116a are in better condition than 

the six formerly available. All are small, their diameter 

ranging from 12 to 30 mm. Their ribs consistently are 

closely spaced. Whether this Trochita is related to T. 

radians, as it appears to be, is questionable. On zoogeographic grounds it is doubtful that a Miocene Caribbean species is closely related to a species now living in 

waters bathed by the Humboldt Current: an aspect not 

considered in chapter A.

The ribs of the recently described late Miocene Florida species, T. floridana (Olsson and Petit, 1964, p. 563, 

pi. 81, figs, 2, 2a), the only species from eastern United 

States, not only are very closely spaced, they are also exceptionally high.

Occurrence: La Boca formation (early Miocene), localities 115a, 115b (Trochita? sp. for both localities, assigned to Culebra formation in chapter A), 116, 116a.

Genus Crucibulum Schumacher (p. 82)

Submenus Crucibulum s.s.

Crucibulum (Crucibulum) spinosum (Sowerby)

Plate 73, figure 7

Calyptraea spinosa Sowerby, The genera of recent and fossil 

shells, fasc. 23 [p. 142], pi. 151, fig. 4, 1824 (age and locality 

not specified).

Crucibulum spinosum (Sowerflby), Ball, U.S. Natl. Mus. Proc., v. 

37, p. 173, 233, 1909 (living, California to Chile).

Crucibulum (Crucibulum) spinosum (Sowerby), Olsson, Neogene 

mollusks from northwestern Ecuador, Paleontological Research Inst, p. 196, pi. 34, fig. 5, 1964 (Miocene, Ecuador).

Crucibulum auriculatum Chemnitz, Sowerby, Monograph of the 

family Calyptraedae: in Thesaurus conchyliorum, p. 60, pi. 

3, figs. 7-14, 1883 (living, Central America).

Crucibulum piliferum Guppy, Sci. Assoc. Trinidad Proc., pt. 3, 

p. 172,1867 (Pliocene, Trinidad) ; reprint, Bull. Am. Paleontology, v. 8, no. 35, p. 51,1921.

Crucibulum (Crucibulum) piliferum Guppy, Jung, Bull. Am. 

Paleontology, v. 55, no. 247, p. 475, .pi. 47, figs. 14-16, 1969 

(Pliocene, Trinidad).

Small, subcircular, low-spired, apex subcentral. 

Capulid protoconch and about first half of first postprotoconch whorl smooth. Kemainder of shell sculptured with radial ribs of two ranks: (1) narrow, widely 

spaced ribs bearing low broken spines, generally appearing as stubby tubes or vaulted scales; (2) low, crowded, 

more or less irregular, minutely nodose ribs, generally 

trending at low angle to first order ribs. Cup broken, except basal part.

Height 9.7 mm, diameter 15.2 mm (figured specimen).

A small nicked Crucibulum in the large collection 

from the lower part of the Gatun formation at locality 

138c is identified as G. spinosum, now living in eastern
GASTROPODS, SCAPHOPODS, PELE.CYPODS: NUCULIDAE TO MALLEIDAE 475

Pacific waters. It presumably is immature, but may represent a small Miocene race, smaller than the Pliocene 

O. piliferum, which is considered to be a synonym of 

O. spinosum.

This is an example of a paciphile at the species level; 

that is, a species that formerly lived in the present 

Caribbean region, but now is extinct there and survives 

in eastern Pacific waters. Examples at the species level 

are rare.

Occurrence: Lower part of Gatun formation (middle 

Miocene), locality 138c. Esmeraldas formation (late 

Miocene), Ecuador. Melajo clay member of Springvale 

formation (late Miocene), Trinidad (immature, identification doubtful). Courbaril member of Morne 

1'Enfer formation (early Pliocene), Trinidad (immature, identification doubtful). Matura member of Talparo formation (early Pliocene), Trinidad. Living, eastern Pacific Ocean.

Eamily CYPRAEIDAE (p. 193) 

Genus Siphocypraea Heilprin

Heilprin, Wagner Free Inst. Sci. Trans., v. 1, p. 86, 1887. 

Type (monotype) : Cypraea (Siphocypraea) problematica Heilprin, Pliocene, Florida.

Subgenus Muracypraea Woodring (p. 194)

Since Muracypraea was proposed as a subgenus of 

Oypraea its status has been discussed by several authors. 

The most satisfactory arrangement is that proposed by 

Olsson and Petit (1964, p. 577; 1968, p. 280), who classified it as a subgenus of Siphocypraea. Ooomans (1963, 

p. 54) rejected Muracypraea as a synonym of Akleistostoma (Gardner, 1943(1944)-48, p. 213, 1948; type 

(orthotype) : Cypraea carolinensis Conrad, late Miocene, North Carolina, Florida). Countless specimens of 

late Miocene age have turned up recently in Florida. 

They Show gradation in a carolinensis-problematica 

lineage (Olsson and Petit, 1964, p. 556-560). That lineage is unknown in the Caribbean region, and Muracypraea is unknown in Florida.

Family OVTJLIDAE 

Genus Cyphoma Roding 

Roding, Museum Boltenianum, p. 21, 1798.

Type (logotype, Herrmannsen, Indicis generum malacozoorum, 

v. 1, p. 355, 1847) : Ovula gibbosa (Linne) ; that is, Cyphoma 

gibbosa R'6ding=Bulla gibbosa Gmelw=Bulla gibbosa 

Linne, living, North Carolina to West Indies and northern 

South America.

As noted by Winckworth (1945, p. 139), though 

Cyphoma is a neuter noun, Roding chose to use it as 

though it were feminine.

Cyphoma aff. C. intermedia (Sowerby) 

Plate 72, figures 13, 14

Large, thin-shelled, strongly inflated. Internal mold 

of later part slightly -bulging at middle. Apertural 

features unknown.

Height (almost complete) 41 mm (estimated restored 

height 45 mm), diameter 20.3 mm (figured specimen).

An internal mold from the La Boca formation at 

locality lOlh is of special interest as the earliest representative of the endemic American genus Cyphoma. A 

little of the thin shell adheres to the mold. The outline 

indicates alliance to O. intermedia (Sowerby, 1848, p. 

479, pi. 100, figs. 61, 62), which ranges from North 

Carolina to Brazil. The fossil, however, is more inflated. 

The mold would not reproduce the low hump of C. intermedia, although it shows a slight bulge. A fine specimen of G. intermedia (USNM 646419) was found by 

Mrs. Shirley E. Hoerle in Olsson's unit A in peninsular 

Florida (Olsson, in Olsson and Petit, 1964, p. 521). It 

is as large as the La Boca fossil but is more slender. 

The anatomy of C. intermedia, was described by Bayer 

(1943, p. 109, pi. 14, fig. 27).

G. puana (Anderson) (1929, p. 1.40, pi. 9, figs. 9,10; 

Miocene, Columbia), a small species, evidently is related to C. intermedia.

G. mcgintyi Pilsbry (Pilsbry and McGinty, 1939, 

p. 2, pi. 1, figs. 3, 3a, 4,11,12) occurs in the late Miocene 

Limon formation of Costa Rica (USGS 20468) and 

O. gibbosa (Linne) in the late Pliocene Moin formation 

of that country: Dall's Ultimus precursor (in Guppy 

and Dall, 1896, p. 318, pi. 29, figs. 2,3).

Occurrence: La Boca formation (early Miocene), 

locality lOlh.

Family NATICIDAE (p. 84) 

Subfamily GLOBTTLARII1J-AE (p. 94) 

Genus Globularia Swainson (p. 94)

Subgenus Globularia s.s. (p. 94)

Globularia (Globularia) megista Woodring n. sp.

Plate 67, figures 13, 16-18

Large, subglo'bose, spire of moderate height, whorls 

narrowly channeled adjoining suture. Faint spiral lineatioii apparent on some shells. Aperture expanded. 

Umbilicus moderately wide. Sheath wide, bordered by 

sharp rim. Lobe wide, its outer edge generally well defined. (For terms sheath, rim, and Idbe see Wrigley, 

1946, p. 88 and p. 94 of present report).

Height 68 mm, diameter 57 mm (type). Estimated 

restored height 75 mm, diameter 60 mm (largest 

specimen).

Type: USNM 646682.

Type locality: 23b (USGS 24553, Upper course of 

Rio Palenque, 3.4 km in direct line west of Nuevo
476 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

San Juan and 1.3 km northwest of settlement of 

Palenque, Colon Province, Panama), Gatuncillo 

formation.

Fourteen half-mature to mature specimens (height 

aibout 40 to an estimated 75 mm) and 36 immature 

(height 1.'5 to 17 mm) of this large species are available. 

Partis of the outer and "basal lips are missing on all, 

except some of the immature shells, or cannot be reconstructed satisfactorily from small fragments.

In umbilical features (umMlicus, sheath, rim, and 

lobe) 6r. megista is similar to G. recurva recurva 

(Aldrich) (Palmer, 1937, p. 133, pi. 14, figs. 7, 8; middle 

Eocene, Alabama), but is larger and has a narrower 

sutural channel. In size, however, it is comparable to 

G. recurva dumblei (Heilprin) (Palmer, 1937, p. 134, 

pi. 14, fig. 10, 11; middle Eocene, Texas). Though in 

umbilical features 6r. megista closely resembles the middle and late Eocene G. patula (Lamarck) (Deshayes, 

1824-37, p. 169, pi. 21, figs. 3, 4, 1832; Wrigley, 1946, 

p. 90, fig. 5), of the Anglo-Parisian basin, that species 

has a sutural narrow step instead of a channel and is 

smaller.

Occurrence: Gatuncillo formation (late Eocene), 

locality 23b.

Family CASSIDIDAE (p. 197)

Genus Semicassis Mbrch (p. 198)

Subgenus Echinophoria Sacco (p. 198)

Semicassis (Echinophoria) tostoma Woodring, n. sp.

Plate 71, figures 9, 12-14

Small, subglobose, distinctly shouldered. Terminal 

varix missing, preceding varix on body whorl generally 

absent. Sculpture consisting of weakly noded, low, narrow spiral threads, alternating with narrower, undulated threads. Nodes strongest on shoulder spiral thread, 

progressively more subdued downward on body whorl. 

Two similar, but narrower, undulated threads between 

shoulder and suture, one to three fine, secondary threads 

between them and flanking them. Outer lip and end of 

siphonal canal missing. Preserved upper part of siphonal f asciole inflated.

Height (incomplete) 28 mm, diameter (terminal 

varix missing) 23.5 mm (type). Height (almost complete) 20.7 mm, diameter (terminal varix missing) 16.8 

mm (immature paratype).

Type: USNM 646713; paratype USNM 646714.

Type locality: lOlh (TJSGS 23652, Panama Canal, 

west side of Las Cascadas Eeach, Canal Stations 1608 

to 1612 plus 23 meters, near top of canal cliff, Canal 

Zone), La Boca formation.

Semicassis tostoma is abundant in the La Boca formation at the type locality (30 specimens) and four

immature specimens were collected at locality lOli. 

Much or all of the thin shell is missing on all of them.

The sculpture is more subdued than that of the two 

species from the Caimito formation described on pages 

198-199, and that of S. rondeleti (Basterot) (Cossmann 

and Peyrot, 1922-24, p. 423, pi. 12, figs. 16, 17, 1924) 

from the Burdigalian of Aquitaine.

Occurrence: La Boca formation (early Miocene), localities lOlh, lOli.

Family MUBICIDAE (p. 214)

Subfamily OCENEBRINAE?

Genus Leptomurex Woodring, n. gen.

Type: Leptomurex acares Woodring, n. sp., Gatuncillo formation.

Small, moderately inflated, distinctly shouldered, 

lacking spines and varices. Uppermost part of all except earliest whorls abruptly turned upward, greatly 

attenuated in thickness, and overlapping lower third of 

preceding whorl. Axial sculpture consisting of wide, 

widely spaced ribs; spiral sculpture of low, wide bands, 

confined to body whorl. Siphonal canal of moderate 

length, deflected laterally from axial alinement and 

slightly bent backward. Siphonal notch shallow.

The position of the suture is the most diagnostic 

feature of this genus. It is not located at the abrupt 

angulation of the whorl, where it would be expected, 

but a third of the way up the preceding whorl. Though 

it is undesirable to base a genus on a species represented by one specimen, so far as I am aware the suture 

is unique for a muricid.

The subfamily status is uncertain, but the lack of 

spines and varices favors assignment to the Ocenebrinae.

Leptomurex acares Woodring, n. sp.

Plate 68, figures 22, 23

Protoconch blunt, li/^-whorled, lower edge, except 

that of tip, slightly angulated, end marked by disappearance of angulation and appearance of axial ribs. 

Ten ribs on first post-protoconch whorl, first few closely 

spaced and weak. Seven ribs on body whorl. Growth 

lines strong, sublamellar on ribs. Outer lip broken back, 

only uppermost part preserved. Weak lirae within aperture at lower end of broken lip. Four widely spaced 

lirae far within aperture opposite penult rib. Other 

features as described under genus.

Height 11.3 mm, diameter 6.8 mm (type).

Type: USNM 646684.

Type locality: 23b (USGS 24553, Upper course of 

Rio Palenque, 3.4 km in direct line west of Nuevo San 

Juan and 1.3 km northwest of settlement of Palenque, 

Colon Province, Panama), Gatuncillo formation.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALLEIDAE 477

Whether the single specimen is immature is indeterminable. Small size, however, is not unusual among 

Eocene muricids.

Occurence: Gatuncillo formation (late Eocene), locality 23b.

Subfamily TYPHINAE (p. 220)

Genus Typhis Montfort (p. 220)

Subgenus Pilsbrytyphis Woodring (p. 220)

Typhis (Pilsbrytyphis) woodringi (Gertman)

Siphonochelus (Pilsbrytyphis) woodringi Gertman, Tulane

Studies Geology and Paleontology, v. 7, no. 4, p. 180, pi. 7,

figs. 6a, 6b, 1969 (Miocene, Canal Zone). 

Typhis (Pilsbrytyphis) gabbi Brown and Pilsbry, Woodring,

this report, p. 220, pi. 32, figs. 2, 3, 5, 7, 1959 (Miocene,

Canal Zone).

During the preparation of chapter B, I neglected to 

compare the Typhis identified as T. gcitibi with the 

type of that species. The type is smaller, less slender, 

and, as pointed out by Gertman, its sculpture is basically 

spiral rather than axial, and a buttress extends from a 

varix to the preceding whorl. The specimen illustrated 

in chapter B on plate 32, figures 5 and 7, was selected 

as the type of T. woodringi. When it was unpacked in 

Washington it was found to be damaged.

Contrary to Gertman's statement (1969, p. 179), the 

type of T. gabbi, from the middle part of the Gatun 

formation, is the only specimen of that species. He 

alleged that all the specimens of T. woodringi are from 

the upper part of the Gatun formation, although it was 

recorded from the middle part (loc. 147g) on page 

221. A total of 29 is now available from the upper part, 

but only one from the middle part. It seems strange that 

two species of this unusual subgenus are found in the 

Gatun formation.

Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle part, eastern area, locality 147g. Upper part, eastern area, localities 175,176, 

176a, 177b, a lot collected by John K. Embich.

Subfamily THAIDINAE (p. 222, as family) 

Genus Gymia Mbrch (p. 223) 

Subgenus Tritonopsis Conrad

Conrad, Am. Jour. Conchology, v. 1, p. 20,1865. 

Type (monotype) : Triton subalveatum Conrad, Oligocene, 

Mississippi.

Gymia (Tritonopsis) n. sp. 

Plate 70, figures 26, 27

Small, inflated, body whorl angulated at shoulder. 

Early whorls missing. Remaining whorls sculptured 

with three coarsely noded spiral bands between shoulder 

and suture, axial swellings between bands alined with 

nodes (nodes and swellings greatly reduced or suppressed on last third of body whorl), and two, later

three, secondary threads between them. Four bands, decreasing in width downward, on preserved part of body 

whorl below shoulder, one to three secondary threads 

between them. Strong growth threads on entire shell, 

especially between spiral bands and threads. Strong 

lirae on interior of outer lip. Columellar fold strong. 

Basal part of siphonal canal and all of siphonal f asciole 

missing.

Height (incomplete) 13.5 mm (estimated restored 

height 17 mm), diameter 10.3 mm (figured specimen).

The Gatuncillo formation at locality 23a yielded the 

earliest known species of Cymia. It is left unnamed, as 

the one specimen is in poor condition. It has been repaired as far as possible. The position of the columellar 

fold, far down on the columella, probably is an artifact, 

due to faulty repairing.

This new species is similar in sculptural pattern to C* 

subalveata, the Oligocene type of Tritonopsis, but the 

secondary sculpture of the Panama species is more delicate. It is angulated also at the shoulder, whereas the 

Oligocene species is rounded, as well as smaller, if the 

single specimen is mature.

Occurrence: Gatuncillo formation (late Eocene), 

locality 23a.

Family BTTCCINIDAE (p. 256) 

Genus Engina Gray

Gray, Zoology of Captain Beechey's voyage * * * in His Majesty's ship Blossom, p. 112,1839.

Type (logotype, Gray, Zool. Soc. London Proc., p. 133, 1847) : 

Engina zonata Gray (Enzina by error) (=Purpura turbinella Kiener), living, West Indies.

A photograph of the type species was published by 

Bartsch, who was misled by Gray's statement concerning the size. The error was corrected by Orr, who republished the photograph at original magnification, designated the specimen as the lectotype, and identified it as 

the common West Indian Engina turbinella. The two 

papers just mentioned are cited in the following 

synonymy.

Engina turbinella (Kiener) 

Plate 74, figures 4, 5

Purpura turbinella Kiener, Species g6ne"ral et inconographie des 

coquilles vivantes, Genre Pourpre, p. 29, pi. 9, fig. 25, 1835- 

36 (living, locality unknown [West Indies]).

Engina turbinella (Kiener), Warmke and Abbott, Caribbean 

sea shells, p. 116, pi. 21, fig. d, 1961 (living, Florida Keys) 

and West Indies).

Not Engina turbinella (Kiener), Dall, Wagner Free Inst. Sci. 

Trans., v. 3, pt. 1, 131, 1890 (Pliocene, Florida) ; =Engina floridana Olsson and Harbison.

Engina sonata Gray, Zoology of Captain Beechey's voyage * * * 

in his Majesty's ship Blossom, p. 113, 1839 (living, Atlantic 

Ocean). Bartsch, U. S. Nat. Mus. Proc., v. 79, art. 15, p. 7, 

pi. 1, fig. 6, 1931 (living, locality not specified). Orr, Nautilus, v. 75, p. 107, pi. 10, figs. A, B, 1962 (living, West Indiesi).
478 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Small, inflated, biconic, concave between shoulder and 

suture. Sculpture consisting of wide, swollen axial ribs 

(nine on body whorl), a subdued primary spiral cord 

near suture, seven primary spiral cords on body whorl 

between shoulder and base, swollen on ribs, and closely 

spaced secondary spiral threads between primary cords. 

Interior of outer lip coarsely denticulate. Elongate, low 

denticles on columellar lip, a stronger denticle on upper 

part of parietal wall opposite a denticle on outer lip. 

Base of columella thickened. Long, narrow ridge on 

outer-lip side of insertion of siphonal canal. Siphonal 

canal short; siphonal notch shallow; siphonal fascicle 

slightly inflated.

Height (not quite complete) 10.9 mm, diameter 7 mm 

(figured specimen).

A small specimen of Engina turbinella was found in 

the lower part of the Gatun formation at locality 138f. 

The tip is worn and corroded, and the apertural face is 

worn. Many living shells are in the same condition, as 

the species lives in water a few feet deep on rocky bottoms. Though the primary spiral cords are more uniform than those of the usual run of E. turbinella, the 

fossil closely resembles a shell from suction-dredge tailings on Payardi Island, 3 km northeast of locality 138f. 

Closely related forms on the Pacific side of Panama 

have been named E. panamensis and E. tabogaensis 

(Bartsch, 1931, p. 7, pi. 1, fig. 7; p. 8, pi. 1, fig. 8, 

respectively).

Occurrence: Lower part of Gatun formation (middle 

Miocene), locality 138f. Living, Florida Keys and Bahamas to northern Brazil.

Genus Bailya M[axwell] Smith

M[axwell] Smith, Panamic marine shells, p. 22,1944. 

Type (orthotype) : Triton anomalus Hinds, living, eastern Pacific Ocean, Nicaragua to Panama.

Triton parvus C. B. Adams (Clench and Turner, 

1950, p. 322, pi. 40, fig. 12) or the closely related, if not 

synonymous, Phos intricatus (Dall, 1883 (1884), p. 325, 

pi. 10, fig. 9) would have been a better choice as the type 

species. Triton anomalus is a rare species, and its radula 

is unknown. Two shells from the Gulf of Dulce, Costa 

Eica, are in USNM collections (424961). Dr. H. A. Kehder informs me that the radula of Triton parvus is 

buccinid.

Bailya crossata Woodring, n. sp. 

Plate 77, figures 14, 15

Moderately small, slender, somewhat turreted. Protoconch missing except last half whorl, which merges 

into first post-protoconch whorl. Sculpture consisting of 

narrow axial ribs, overridden by narrow primary spiral 

threads and closely spaced, low secondary spiral threads. 

Primary spiral threads swollen on ribs. Thirteen axial

ribs on body whorl and eight primary spiral threads 

above base. Base sculptured with four frilled primary 

spiral threads on siphonal fascicle, terminal frill strong 

(uppermost two threads more widely spaced than 

others), and a stronger, more widely spaced, frilled 

primary thread still higher. Axial ribs attenuated or 

suppressed between these basal primary threads. Secondary threads between them, as on remainder of 

whorl. Entire shell delicately frosted by microscopic 

growth threads. Outer lip varicose, edge frilled, interior 

bearing short, low lirae. Columellar lip narrow. An 

elongate denticle on upper part of parietal wall opposite a lira on outer lip. Siphonal canal short; siphonal 

notch moderately deep; siphonal fascicle slightly 

inflated.

Height 16.9 mm, diameter 7.5 mm (type).

Type :USNM 646724.

Type locality: 138e (USGS 22391, Spoil from refinery-site suction-dredge operations on west side of 

Payardi Island, Colon Province, Panama), lower part 

of Gatun formation.

The strongly frilled basal spiral threads alone distinguish Bailya crossata from other species. In addition 

it is slightly larger, and the spire is more distinctly turreted. It is the first Tertiary species from the Caribbean 

region to be recorded and the earliest species now 

known. The type is the only specimen.

Occurrence: Lower part of Gatun formation (middle 

Miocene), locality 138e.

Family MELONGENIDAE (p. 273)

Genus Melongena Schumacher (p. 273)

Melongena cf. M. propatula Anderson

Plate 73, figure 11

Of medium size, whorls uniformly overlapping earlier 

whorl. Spiral sculpture of wide, or fairly wide, bands on 

spire whorls and body whorl. On body whorl most distinct on and above shoulder, but extending in subdued 

form down to siphonal fascicle. A row of blunt spines 

on shoulder of body whorl (one spine on preserved half 

of penult). Another row of smaller spines near base. 

Siphonal fascicle narrow, strongly inflated.

Height (almost complete) 81.5 mm, diameter (not including spines), 49 mm (figured specimen).

The apertural face of the single specimen of this 

Gatun species is obliterated by corrosion. The wide, or 

fairly wide, spiral bands suggest alliance with Melongena propatula (Anderson, 1929, p. 133, pi. 11, figs. 1,2), 

a middle Miocene Colombian species. If it is that species, 

however, it represents a stage preceding development of 

the greatly expanded mature body whorl. The type of 

M. propatula is in poor condition and so is a somewhat 

larger virtual topotype (USGS 10987).
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLEIDAE 479

The sculpture of the incomplete La Boca specimen, 

mentioned on page 273, is comparable.

Occurrence: Lower part of Gatun formation (middle 

Miocene), locality 138f.

Family XANCIDAE (p. 285)

Genus Xancus Roding (p. 285)

Xancus cf. X. validus (Sowerby)

Xancus cf. X. rex Pilsbry and Johnson, Woodring, this report,

p. 286, 1964 (Miocene, Canal Zone).

Xancus sp., Woodring, this report, p. 286 (Oligocene [Miocene], 

Canal Zone).

E. H. Yokes (1964, p. 47, fig. 1), who illustrated the 

lectotype of Xancus validus, has shown that X. rex is a 

synonym of that species. The species recorded in chapter C as X. cf. X. rex occurs in the Culebra and La Boca 

formations.

X. validus is known to occur in the Baitoa formation 

of the Dominican Republic (USGS 8558, 8668), as well 

as in the Thomonde formation of Haiti (USGS 9779, 

9782, 9948), both of late early Miocene age. It was not 

found in the Cercado or Gurabo formations by the 

Maury or USGS expeditions. The fine specimen illustrated by Maury (1917, p. 83, pi. 13, fig. 5) was collected by Gabb. Col. Heneken, whose fossils were described by Sowerby, collected along Rio Yaque del 

Norte at and south of Santiago, and also farther west 

on Rio Amina, Rio Mao, and Rio Gurabo, and at other 

scattered localities (Heneken, 1853, p. 122-125). The 

Baitoa formation crops out on Rio Yaque del Norte 

south of Santiago. To be sure, however, 90 percent of 

the stratigraphically allocated species described by 

Sowerby occur in the Gurabo formation (and 20 percent exclusively in that formation), which also crops 

out on Rio Yaque del Norte south of Santiago, as well 

as on the other rivers mentioned.

Occurrence: Culebra formation (early Miocene), localities 104a, 104b. La Boca formation (early Miocene), 

locality 116a (assigned to Culebra formation in chapter C). Emperador limestone member of La Boca formation (early Miocene), Madden basin, locality 71 (assigned to Caimito formation in chapter C).

Xancus validus hysterus Woodring, n. subsp. 

Plate 73, figure 10; plate 74, figures 2, 3

Xancus validus validus (Sowerby)?, Woodring, this report, p. 

286, pi. 47, fig. 13,1964 (Miocene, Canal Zone).

Larger than Xancus validus validus, but whorl profile similar. Earliest preserved whorls weakly shouldered; shoulder later progressively stronger. Earliest 

knobs low, wide, strongly pinched in plane parallel to 

suture; at later stage knobs stronger, but wider and 

more pinched than those of nominate subspecies. Earliest preserved whorls worn, showing wide axial ribs

and traces of spiral threads. A weak spiral cord appearing later well below shoulder. Mature body whorl sculptured with four widely spaced, subdued spiral cords between shoulder and pillar, and closely spaced, subdued 

cords on pillar. Microscopic spiral lineation visible on 

well-preserved shells. Growth threads occasionally exaggerated, but not strongly exaggerated at widely and 

regularly spaced intervals on slope between suture and 

shoulder.

Height (incomplete) 265 mm (estimated restored 

height 300 mm), diameter 110 mm (type).

Type: USNM 646726; paratype USNM 646727.

Type locality: 159b (USGS 6273, Lock site [at 

Gatun], Canal Zone, 10 to 50 feet (3 to 15 meters) below 

surface, middle part of Gatun formation.

The large size, late appearance of knobs, wider and 

more pinched knobs, and absence of strong, widely 

spaced, exaggerated growth threads on the slope between 

the suture and the shoulder distinguish this subspecies 

from the nominate subspecies. The exaggerated growth 

threads of the nominate subspecies are shown to good 

advantage in Maury's illustration (Maury, 1917, p. 83, 

pi. 13, fig. 5) and in Pilsbry's illustrations of Xancus 

rex (Pilsbry, 1922, p. 342, pi. 26, figs. 5, 8).

Only four specimens of X. validus hysterus are available. The specimen serving as the type was unaccountably overlooked when plate 47 was made up. The type 

and the immature paratype were collected at the same 

locality. Another large shell in the same lot somewhat 

larger than the type, but less complete is a little more 

inflated than the type (diameter 120 mm).

Occurrence: Middle part of Gatun formation (middle 

Miocene), eastern area, localities 155,159b.

Xancus dodonaius praelaevigatus (E. H. Yokes)

Xancus praevoideus (error for praeovoideus, see errata following

p. 251) Maury, Bull. Am. Paleontology, v. 5, no. 29, p. 83, pi.

14, fig. 18, 1917 (Miocene, Dominican Republic). Not TurMnella praeovoidea Vrendenberg, 1916. 

Xancus validus falconensis H. K. Hodson, Woodring, this report,

p. 286, pi. 46, figs. 4-6, 1964 (Miocene, Canal Zone). 

TurMnella praelaevigata E. H. Vokes, Tulane Studies in Geology,

v. 2, no. 2, p. 52, 1964; new name for Xancus praeovoideus

Maury.

Type: Cornell Univ. 36829. 

Type locality: Bluff 3, Cercado de Mao, Dominican Republic,

Cercado formation.

E. H. Yokes' (1964a, p. 96) objection to classifying 

Xancus falconensis as a subspecies of X. validus is justified.

Despite the identification in chapter C, which was 

made without benefit of specimens of X. falconensis, a 

series of 11 topotypes shows that X. falconensis is not 

a suitable name for the faintly knobbed or smooth Xancus from the Gatun. X. falconensis is slender and has
480 GEOLOGY AND PALEONTOLOGY OP CANAL ZONE

a strongly constricted pillar. Its shoulder, not far from 

the suture, is rounded or subrounded and on some specimens is marked by an obscurely undulated, low spiral 

thread. So far as known it is relatively small (maximum 

estimated restored height 170 mm).

Two species of Xancus are represented in the collection from the Oak Grove sand member of the Shoal 

Eiver formation at USGS locality 2646, one smooth, the 

.other knobbed. The only fairly complete specimen, 

which is smooth and immature, was selected as the type 

of X. dodonaius (Gardner, 1926-47, p. 440, pi. 49, fig. 2, 

1944). A fragment of the body whorl of a larger shell 

also is smooth. Another specimen, consisting of the 

spire and upper part of half of the body whorl, is 

larger and more inflated than the type. The body whorl 

has a distinct shoulder, undulated by long, thinly 

pinched vestigial knobs, like those of X. validus hysterus 

at a comparable growth stage. The fragment of a large 

shell mentioned by Gardner, was collected at a nearby 

locality (USGS 7054). It is strongly shouldered and 

bears long, pinched knobs, like mature X. validus hysterics. No mature shells of X. dodonaius are in USNM 

collections. A mature specimen from the Chipola formation (height 210 mm) was illustrated by E. H. Yokes 

(1964, p. 50, pi. 1, fig. 2a).

X. praelaevigatus occurs in the Cercado and Gurabo 

formations of the Dominican Republic. Five specimens 

are in USNM collections from each formation (USGrS 

8525; 3516, 8519 respectively). Maury's photograph 

of the type of her X. praeovoideus is a better representation than the drawing in her Brazilian monograph 

(Maury, 1925a, p. 623, pi. 7, fig. 12). This Xancus is so 

similar to X. dodonaius that it is given subspecific rank 

under that species. The chief difference is that the sculpture of X. praelaevigatus disappears at a later growth 

stage.

The Gatun Xancus, which occurs also in the Darien 

area, is now identified as a large, variable, slender to 

moderately inflated, faintly knobbed to smooth form of 

X. dodonaius praelaevigatus. The maximum estimated 

height of USNM Dominican Republic specimens is 

180 mm, but Pilsbry (1922, p. 343) estimated 200 mm 

for the largest in the Gabb collection. Estimated heights 

for the largest Gatun and Darien shells are 250 and 300 

mm, respectively.

Despite its name, it is unlikely that X. dodonaius 

praelaemgatus is a predecessor of the small, ovate, living Brazilian X. laevigatus.

Occurrence: For occurrence in Gatun formation see 

p. 287. Middle Miocene deposits, Darien area, Panama 

(USGS 8430, 8476, 8477, 8479). Cercado and Gurabo 

formations (middle Miocene), Dominican Republic.

Family XANCIDAE?

Genus? 

Plate 73, figures 12,13

Of medium size, spire of moderate height, whorls 

rapidly enlarging in diameter. Intermediate and late 

whorls strongly shouldered; widely spaced, spinose 

knobs on shoulder of late whorls. Earliest whorls missing, later early whorls worn, but showing gross features. 

Axial swellings on lower part of earliest preserved whorl 

transformed on next whorl into widely spaced knobs at 

base of whorl and evenutally into sinose knobs. Undulations on band adjoining suture transformed into closely 

spaced knobs, gradually flattened in plane parallel to 

suture, gradually becoming bipartate also in plane parallel to suture, and eventually transformed into strongly 

bifid knobs. Two widely spaced, low, undulated spiral 

cords near suture, followed by two closely spaced, low 

spiral threads near shoulder. Undulations transformed 

into pinched knobs on last bit of shell. Suture below 

shoulder knobs distinct on earliest preserved whorls, 

obscure or concealed on later whorls. Lower part of 

body whorl missing. Columella thick at broken end, 

upper part bearing 10 closely spaced, narrow wrinkles.

Height (incomplete) 36 mm, diameter (including 

knobs) 39.7 mm (figured specimen).

The affinities of this bizarre fossil are undetermined. 

The bifid knobs are especially bizarre. It is described 

and illustrated in the hope that a more complete specimen may be found eventually. It was more or less covered with a hydrozoon crust, especially the upper part 

of the spire, which was broken and worn before encrustration. The crust was removed, or almost entirely 

removed. Though the suture is distinct on the early 

preserved whorls, it is obscure or concealed on late 

whorls. Where the preservation is good on late whorls, 

fine growth lamellae extend across where the suture 

should be, indicating that an extension of the mantle 

covered it.

Were it not for the columella, it would not be unreasonable to interpret it as a bizarre Vasum. It is by no 

means certain, however, that it is a xancid; it may possibly be a cymatid.

Occurrence: Lower part of Gatun formation (middle 

Miocene), locality 138c.
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLEIDAE 481

Family CANCELLARHDAE (p. 334) 

Genus Cancellaria Lamarck (p. 334)

Subgenus Cancellaria s.s. 

Cancellaria (Cancellaria) epistomifera sathra Woodring, n. name

Cancellaria (Cancellaria) epistomifera lipara Woodring, this 

report, p. 337, 1970, not Cancellaria lipara Woodring, U.S. 

Geol. Survey Prof. Paper 222, p. 76, 1950 (1951).

To propose a junior homonym is unfortunate, but for 

an author to propose a name invalidated by one of his 

own names is doubly unfortunate. I am indebted to 

Mr. K. E. Petit for pointing out the error.

Family TTTRRIDAE (p.360) 

Subfamily CLAVINAE (p. 374) 

Genus Leptadrillia Woodring?

Woodring, Carnegie Inst. Washington Pub. 385, p. 159, 1928. 

Type (orthotype) : Turris (Surcula) parkeri Gabb, Miocene, 

Dominican Republic and Jamaica.

Leptadrillia? n. sp. 

Plate 69, figure 9

Of medium size, slender, whorls almost flat-sided. 

Early whorls missing. Sculpture consisting of narrow 

axial ribs, almost straight and axial on earliest preserved whorl, later arcuate and protractive; seven on 

last preserved whorl. Spiral sculpture limited to irregularly spaced lineation. According to ribs and growth 

lines, anal sinus wide and shallow. Aperture missing.

Height (incomplete) 22.5 mm, diameter (almost complete) 9.7mm (figured specimen).

Though this Eocene species has distinctive features, 

it is left unnamed, as both protoconch and aperture are 

missing on the only specimen.

It is larger and more flat-sided than the Miocene to 

living genus Leptadrillia, and has a narrower apical 

angle. It is much larger than early Tertiary clavine 

turrids from southeastern United States characterized 

by absence of spiral sculpture, except on the pillar. 

Pleurotoma tantula (Conrad, 1848, p. 115, pi. 11, fig. 21, 

a poor illustration; Oligocene, Mississippi), which has 

a height of 11 mm, is the largest of these early Tertiary 

species. They are not as flatsided as the Panama species.

Occurrence: Gatuncillo formation (late Eocene), locality 23b.

Family ACTEONIDAE (p. 415) 

Subfamily ACTEONTELLINAE?

Genus Volvariella Fischer 

Fischer, Manuel de conchyliologie, p. 553,1883. 

Type (monotype) : Volvaria lamarcki [lamarckii] Deshayes, 

Eocene, Paris basin.

Volvariella has been assigned to the Mitridae. Cernohorsky (1970, p. 64) recommended transferring it to

the Acteonacea, close to Cylindrites; that is, in the family where Fischer originally allocated it.

Volvariella? species 

Plate 70, figures 23-25

Large for the genus Volvariella, subcylindrical, slender. Spire high, somewhat loosely coiled. Sculpture subdued, consisting of low, narrow, flat, closely spaced 

spiral threads, minutely reticulated by microscopic axial 

threads. Growth lines exaggerated at irregular intervals 

and dark-colored axial bands on mature shells. Aperture narrow, base rounded. Columella not exposed.

Height (almost complete) 21.8 mm, diameter 7.5 mm 

(larger figured specimen). Height (almost complete) 

6.9 mm, diameter 2.6 mm (smaller figured specimen). 

Height (almost complete) 27.5 mm, diameter 8 mm 

(largest specimen).

Four specimens of this species were collected from 

the Bohio (?) formation at locality 41b and one at 

locality 41. All are internal molds to which some shell 

material, replaced by calcite, adheres.

On reasonable grounds these fossils represent the 

genus Volvariella. They have the outline and sculpture 

of that genus. Nevertheless the generic assignment is 

questioned, as the columella is unknown. The lower part 

of the columella was found to be dissolved on the one 

specimen that was ground down. If the species is a 

Volvariella, it is the largest and youngest, even if the 

marine member of the Bohio (?) is of late Eocene age, 

rather than early Oligocene. It is four times as 

large as the only other American species, V. aldrichi 

Cossmann (Palmer, 1937, p. 413, pi. 65, figs. 3, 4; early 

to middle Eocene, Alabama), and its spire is more 

loosely coiled. The early Eocene type of the genus, V. 

lamarckii (Deshayes) (1861-63, p. 543, pi. 104, figs. 1, 2, 

1862), has a height of 11 mm. According to Deshayes' 

illustration, the body whorl is somewhat loosely coiled, 

but Cossmann and Pissarro's illustration (1910-13, pi. 

43, fig. 205 ter-2) shows tighter coiling.

Occurrence: Marine member of Bohio(?) formation 

(late Eocene), localities 41,41b.

SCAPHOPODS

.Family DENTALIIDAE 

Genus Dentalium Linne

Linn6, Systema naturae, 10th ed., p. 785,1758.

Type (logotype, Montfort, Conchyliologie systematique, v. 2, p.

23, 1810) : Dentalium elephantinum Linne, living, western

Pacific Ocean.

The marine member of the Bohio(?) formation at 

localities 40a and 40d contains fragments of a small 

species listed as Dentalium sp.

475-796 O - 73 - 3
482 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Subgenus Dentalium s.s.

Dentalium (Dentalium) armillatum armillatum Toula 

Plate 75, figures 15, 24, 25

DentaUum armillatum Toula, K. k. Geol. Reichsanstalt Jahrb., 

v. 61, p. 496, pi. 31, figs. 8a, 8b, 1911 (Miocene, Canal Zone).

Of medium size, slender, slightly curved. Apical part 

hexagonal, the six ribs narrow and sharply sculptured. 

A secondary rib appearing in each interspace short distance from apical end. At later stage more secondary ribs 

added and cross section becoming circular. Eventually 

as many as 12 secondary ribs in each original interspace, 

and primary ribs reduced to their strength. Entire 

sculpture reduced on anterior part of fragments that 

have greatest diameter. Apical orifice simple.

Length (incomplete at both ends) 40.4 mm, anterior 

diameter 3.9 mm, apical diameter 1.6 mm (figured 

specimen).

Type: Technische Hockschule, Vienna.

Type locality: Gatun Locks excavation, Canal Zone, 

middle part of Gatun formation.

Dentalium armillatum armillatum is the only abundant and widespread Dentalium in the Gatun formation. 

No specimen is entirely complete; that illustrated is the 

largest. Most of the collections consist of fragments, 

chiefly apical fragments. Indeed, five collections (Iocs. 

138c, 139b, 147g, 147h, 147i) consist only of apical fragments at a stage before secondary ribs are introduced. 

Such fragments are indistinguishable from immature 

fragments of D. cossmannianum Pilsbry and Sharp 

(1898, p. 467, pi. 10, fig. 11, pi. 11, figs. 10, 11; Middle 

Miocene, Dominican Republic, Jamaica), which lacks 

secondary ribs at any growth stage. Fragments from 

locality 161 have only a few weak secondary ribs, and 

both primary and secondary ribs are subdued on 

anterior fragments, but are discernible. Five of 29 small 

fragments collected at locality 139b have faint to 

distinct, fine annular sculpture.

This Dentalium is larger than D. equisetum Olsson 

(1964, p. 203, pi. 38, figs. 8, 8a-c; Esmeraldas formation, 

Ecuador) and has stronger sculpture.

D. armillatum armillatwn occurs in the Globorotalia 

fohsi zone of the Brasso formation of Trinidad (USGS 

21230,21234).

Occurrence: Lower, middle, and upper parts of Gatun 

formation (middle Miocene). Lower part, localities 

138c, 138e. Middle part, eastern area, localities 139b, 

139c, 139d, 139e, 139f, 139g, 147b, 147c, 147g, 147h, 147i, 

150a, 158; western area localities 161, 161a, 162a, 169. 

Upper part, eastern area, localities 172,176a, 177, I77b. 

Middle Miocene part of Brasso formation, Trinidad.

Dentalium (Dentalium) armillatum proterum Woodring, n. subsp. 

Plate 71, figures 8, 17

Secondary ribs fewer and weaker than those of 

nominate subspecies. Both primary and secondary ribs 

indistinct on anterior part of shell or disappearing 

there.

Length (incomplete at both ends) 40.2 mm, anterior 

diameter 3.5 mm, apical diameter 1.3 mm (type).

Type :USNM 646697.

Type locality: 54h (USGS 18841, Barro Colorado 

Island, western part of island, mouth of first stream 

north of Zetek House, Canal Zone), Caimito formation.

This subspecies occurs in the moderately deep-water 

facies of the Caimito formation on Barro Colorado Island, where five fairly complete shells and 19 fragments 

were collected. The weakly sculptured fragments from 

the middle part of the Gatun formation at locality 161, 

already mentioned, are intermediate between typical 

forms of the two subspecies.

D. armillatum proterum is the earliest hexagonal 

Dentalium s.s. from the American mainland. According 

to Guppy's locality data ("Nucula beds, Naparima"), 

he found an earlier species in the early Oligocene part 

of the Cipero formation of Trinidad. It was identified 

by Dall (in Guppy and Dall, 1896, p. 325) as his 

D. gouldii, but is not that living species.

Occurrence: Caimito formation (late Oligocene), 

localities 54h, 54k.

Dentalium (Dentalium) bothrum Woodring, n. sp. 

Plate 75, figures 14, 23

Large, slightly curved, inflated, rapidly enlarging, 

strongly ribbed. Apex missing. Earliest preserved part 

sculptured with eight high ribs. Base of ribs pinched, 

crest rounded; interspaces strongly concave. Later a 

rapidly strengthened secondary rib appearing in each 

interspace. Still later a minor tertiary rib in some interspaces. Total of about 28 ribs on incomplete fragment, 

diameter 9 mm. Microscopic axial and annular threads 

on unworn parts of shell.

Length (incomplete at both ends) 39.5mm (estimated 

restored length 65 mm), anterior diameter 8.2 mm, 

apical diameter 3.6 mm.

Type: U'SNM 646730.

Type locality: 179 (USGS 8413, Upper edge of Chilas 

[Chila] village, Rio Indios [Indio], Colon Province, 

Panama), upper part of Gatun formation.

The type, and a fragment of slightly greater diameter, of this rapidly enlarging, strongly ribbed species 

were found in the upper part of the Gatun formation in 

the western area, west of the Canal Zone. The micro-
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 483

scopic sculpture is not preserved on slightly worn parts 

of the shell.

The rapidly enlarging, strongly ribbed shell recalls 

the western Pacific Dentalium elephantinum Linne, 

the type of the genus. D. laqueatum invalidum Emerson 

(1954, p. 184; new name for D. laqueatum regulare 

Henderson, 1920, p. 26, pi. 1, fig. 8; living, West Indies; 

not D. regulare Ahlburg, 1906), which is more slender 

than D. bothrum and has more ribs, is the most similar 

American form.

Occurrence: Upper part of Gatun formation (middle 

Miocene), western area, locality 179.

Subgenus Tesseracme Pilsbry and Sharp 

Pilsbry and Sharp, Manual of conchology, v. 17, p. 249, 1898. 

Type (logotype, Woodring, Carnegie Inst. Washington Pub. 366,

p. 199, 1925) : Dentalium quadrapicale Sowerby, living,

western Pacific Ocean.

Tesseracme is a paciphile subgenus that survived until 

Pliocene time in Florida. (For a definition of the term 

paciphile see p. 322).

Dentalium (Tesseracme) dissimile Guppy 

Plate 75, figures 12, 13

Dentalium dissimile Guppy, Geol. Soc. London Quart. Jour., v. 

22, p. 292, pi. 17, fig. 4, 1866 (Miocene, Jamaica). Gabb, Am. 

Philos. Soc. Trans., n. ser., v. 15, p. 244, 1873 (Miocene, Dominican Republic). Pilsbry and Sharp, Acad. Nat. Sci. 

Philadelphia Proc., v. 49 (1897), p. 469, pi. 11, figs. 3-5, 

1898 (Miocene, Dominican Republic). Maury, Bull. Am. 

Paleontology, v. 5, no. 29, p. 158, pi. 26, fig. 1, 1917 (Miocene, 

Dominican Republic). Pilsbry, Acad. Nat. Sci. Philadelphia, 

v. 73, p. 400, 1922 (Miocene, Dominican Republic).

Dentalium (Tesseracme) dissimile Guppy, Pilsibry, Acad. Nat. 

Sci. Philadelphia Proc., v. 63, p. 166, 1911 (Miocene 

Jamaica).

Dentalium (Tesseracme) dissimile dissimile Guppy, Woodring, 

Carnegie Inst. Washington Pub. 366, p. 199, pi. 27, figs. 

9-14, 1925 (Miocene, Jamaica).

Apical fragment quadrangular. Edges sharply raised. 

Faces smooth.

Length (incomplete at anterior end) 4 mm, anterior 

diameter 0.9 mm, apical diameter 0.6 mm (figured 

specimen).

Type: British Mus. (Nat. History) 64082.

Type locality: Bowden, Jamaica, Bowden formation.

A small apical fragment is the only specimen of this 

Miocene Caribbean species. It represents a stage before 

the appearance of secondary ribs and the assumption 

of a circular cross section. The length of a large Bowden shell is 51 mm and the smallest apical diameter of 

fragments 0.4 mm. An exceptionally large specimen 

from the Gurabo formation (USGS 8519) has a length 

of 73.5 mm, and the extreme apical part is missing.

Dentalium dissimile has been described and illustrated adequately by Pilsbry and Sharp, and Woodring. It first appeared in early Miocene time, was fairly

widely distributed in middle Miocene, and probably 

continued until late Miocene.

The shell of Dentalium ponderosum Gabb (Pilsbry 

and Sharp, 1898, p. 470, pi. 10, figs. 1-3, p. 11, figs. 15, 

16; Woodring, 1925, p. 200, pi. 27, figs. 15-17) is exceptionally thick, even thicker than the diameter of 

the orifice. It is associated with D. dissimile in the 

Bowden, Cercado, and Gurabo formations, and there 

are ^gradations between them. It is better treated as an 

infrasubspecific form of D. dissimile than as a variety 

or subspecies, as has been done.

Occurrence: Lower part of Gatun formation (middle Miocene), locality 137. Thomonde formation (early 

Miocene), Haiti (USGS 9907, 9945, 9946, 9782). Cercado and Gurabo formations (middle Miocene), Dominican Eepublic. Bowden formation (middle Miocene), Jamaica. Middle Miocene, southeastern Costa 

Rica (USGS 5882a, 5882b, 8343). Limon formation 

(late Miocene), Bocas del Toro area, Panama (USGS 

8496, identification doubtful).

Subgenus Fissidentalium Fisetier

Fischer, Manuel de conchyliologie, p. 894,1885. 

Type (monotype) : Dentalium ergasticum Fischer, living, eastern Atlantic Ocean.

The scaphopods of the subgenus Fissidentalium live 

mainly in deep water. They are found in the three formations under consideration that include moderately 

deep-water deposits: the Caimito and La Boca formations and the Chagres sandstone.

Dentalium (Fissidentalium) uscarianum Olsson 

Plate 71, figures 6, 7, 16

Dentalium uscarianum Olsson, Bull. Am. Palentology, v. 9, no. 

39, p. 166, pi. 15, fig. 1, 1922, assigned to subgenus Fissidentalium (Miocene, Costa Rica).

Large, moderately slender, slightly curved, strongly 

sculptured with high, rounded ribs. Apex hexagonal. 

Short distance from apex a rib appearing in each interspace. Other ribs added at later stages and cross section 

becoming circular. Total number of ribs on Caimito 

shells 20 to 26, usually 23, not including a few minor 

ribs. Apical orifice simple.

Length (incomplete at both ends) 52 mm, anterior 

diameter 7.3 mm, apical diameter 2.7 mm (larger figured specimen).

Type: Paleontological Research Inst. 21115.

Type locality: Rio Codes, Limon Province, Costa 

Rica, Uscari formation.

A Fissidentalium, identified as Dentalium uscarianum, is widespread in the moderately deep-water f acies 

of the Caimito formation on Barro Colorado Island. It 

is abundant at locality 54k. The collection from that 

locality consists of some 30 fairly complete shells and
484 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

about 100 fragments of varying size. In addition, scores 

of the smallest fragments were discarded. The anterior 

fragment of greatest diameter (loc. 541) is distorted by 

slight crushing and therefore has an oval outline. The 

diameter is 9.7 to 10.7 mm and the number of ribs is 

23. If this shell were complete, its length would be 

about 100 mm. At a diameter of 0.7 to 0.9 mm the apical 

orifice is simple.

The type of D. uscarianum (anterior diameter 12 

mm), is a fragment of a specimen larger than any Canal 

Zone specimen, and the sculpture is subdued on the anterior part. The apical sculpture of Uscari specimens 

is unknown.

Thirty fragments or poorly preserved specimens 

from the La Boca formation also are identified as D. 

uscarianum. The greatest diameter of those that clearly 

show ribs is about 6 mm. None has more than 15 widely 

spaced ribs. A fragment from the type region of D. 

uscarianum (USGS 8042) is sculptured with 15 ribs 

at the same diameter.

As noted by Olsson, the ribbing is similar to that 

of D. floridense Henderson (1920, p. 64, pi. 10, figs. 

1, 2, 6, 7; living, southern Florida, Barbados, 35 to 110 

fathoms). The ribs of that species are somewhat lower, 

and the apex bears a long, narrow slit on the convex 

side.

Occurrence: Caimito formation (late Oligocene) localities 54g, 54h, 54j, 54k, 541, 54m. La Boca formation 

(early Miocene), localities 99b, lOlh, lOli, 119. Early 

Miocene part of Uscari formation, Costa Rica.

Dentalium (Fissidentalium) granadanum esmeraldum Olsson

Plate 75, figures 32-34

Dentalium (Fissidentalium) esmeraldum Olsson, Bull. Am. 

Paleontology, v. 27, no. 106, p. 80, pi. 6, figs. 1, 2, 10, 1942 

(Oligocene [Miocene], Ecuador, Olsson, Neogene mollusks 

from northwestern Ecuador, Paleontological Research Inst, 

p. 204, pi. 37, fig. 13, pi. 38, fig. 9, 1964 (Miocene, Ecuador).

Large, moderately slender, slightly curved, thickshelled, sculptured with narrow, low, closely spaced ribs. 

Apex missing. Earliest preserved part sculptured with 

20 main and several minor ribs. Thirty main and some 

minor ribs at diameter of 10 mm. Eibs gradually suppressed at diameter of about 10 to 12 mm. Microscopic 

axial and annular threads on unworn parts of shell.

Length (incomplete at both ends) 72 mm, anterior 

diameter 10.3 mm, apical diameter 3.2 mm (large figured specimen).

Type: Paleontological Eesearcih Inst. 4069.

Type locality; Punta Gorda, Esmeraldas Province, 

Ecuador, Esmeraldas formation.

The Chagres sandstone yielded two incomplete shells 

and six fragments of this Ecuadoran species. The apical 

part of the larger illustrated shell (pi. 75, fig. 33) is

badly worn and the remainder somewhat worn, as is the 

type. The sculpture is shown to better advantage by the 

smaller illustrated shell (pi. 75, fig. 32).

As noted by Olsson (1942, p. 81), large shells of the 

nominate subspecies (Anderson, 1929, p. 144, pi. 13, fig. 

3; Las Perdices shale, Colombia) retain their sculpture 

to the anterior end. The nominate subspecies is interpreted as a predecessor of the late Miocene form.

Occurrence: Chagres sandstone (late Miocene), localities 206, 208. Esmeraldas formation (late Miocene), 

Ecuador.

Submenus Graptacme Pilsbry and Sharp

Pilsbry and Sharp, Manual of conchology, v. 17, p. 85, 1897. 

Type (logotype, Woodring, Carnegie Inst. Washington Pub. 366,

p. 201, 1925) : Dentalium eboreum Conrad, living, North

Carolina to West Indies.

Dentalium (Graptacme) species

A minute fragment (length 3 mm, anterior diameter 

0.8 mm, apical diameter 0.5 mm), which was broken in 

half in handling, is the only specimen of Graptacme. 

The sculptured stage is exceptionally restricted; only 

the posterior half bears fine, faint axial threads. A relatively wide, shallow apical notch may be a real notch or 

a break.

Occurrence: Middle part of Gatun formation (middle Miocene), locality 170a.

Submenus Khabdus Pilsbry and Sharp?

Pilsbry and Sharp, Manual of conchology, v. 17, p. 112, 1897. 

Type (orthotype) : Dentalium rectius Carpenter, living, British 

Columbia to California.

Dentalium (Khabdus?) species 

Plate 75, figure 28

Apical fragments distinctly curved, enlarging in diameter at moderately rapid rate. Sculptured with annular rings, oblique to axis of shell, closely spaced or 

more widely spaced. Apical orifice simple.

Length (incomplete at anterior end, not quite complete at apical end) 3.2 mm, anterior diameter 0.8 mm, 

apical diameter 0.3 mm (figured specimen).

Six minute apical fragments of this annulated Dentalium were found in the Gatun formation. The relatively strong sculpture, which is unique in American 

fossil and living species, probably is apical only, as it is 

subdued near the anterior end of the largest fragments. 

The apical diameter of some of the fragments is smaller 

than that of the illustrated specimen.

Omniglypta (Kuroda and Habe, in Habe, 1953, p. 

296; type (orthotype): Dentalium cerinum Pilsbry, 

living, Japan) has been proposed for an annulated western Pacific species. It is unlikely, however, that the 

presumably small Caribbean species is related to the 

moderately large, slender western Pacific species.
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 485

Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle paft, eastern area, locality 153a. Upper part, western area, locality 185.

Subgenus Laevidentalium Cossmann

Cossmann, Soc. Roy. Malacologique Belgique Annales, v. 23, p. 7, 

1888 (pt. 3, p. 11 of separate publication, 1888).

Type (orthotype) : Dentalium incertum Deshayes, lower and 

middle Eocene, Paris basin.

The marine member of the Bohio( ?) formation (loc. 

41b) and the Bohio formation itself (loc. 42d) contain 

smooth fragments indicating species having an estimated restored length of about 40 and 30 mm, respectively. The apical parts are missing. They are 

listed as Dentalium (Laevidentalium ?) sp. It is improbable that they represent the same species, as the 

Bohio fragments are slightly compressed laterally.

Dentalium (Laevidentalium) pyrum Pilsbry and Sharp

Plate 75, figures 5, 16, 31

Dentalium pyrum Pilsbry and Sharp, Acad. Nat Sci. Philadelphia Proc., v. 49 (1897), p. 472, pi. 11, figs. 6, 7, 1898 (Miocene, Dominican Republic).

Small, slender, slightly curved. Apical part circular, 

remainder slightly compressed laterally. Surface 

smooth, polished. Faint growth lines, slightly oblique 

to axis, showing through polished surface of some specimens. Apical orifice bearing a sheath; a narrow slit extending from sheath down into outer shell wall.

Length (incomplete at both ends) 13.6 mm, anterior 

diameter 2.1 by 2.4 mm, apical diameter 1.6 mm (larger 

figured specimen).

Type: Acad. Nat. Sci. Philadelphia 2714.

Type locality: Dominican Bepublic, Miocene.

Dentalium pyrum is known only by fragments wherever it has been found. It is characterized by its slightly 

flattened outline and apical sheath and slit. The largest 

of eight Gatun fragments, and also an apical fragment 

showing a perfectly preserved sheath and slit, are illustrated (pi. 75, figs. 5,16, pi. 75, fig. 31, respectively). The 

slit is longer on another specimen that has a preserved 

apex (locality 161c). Apical features of the type shown 

by both are found in some species of the subgenera 

Antalis. Fissidentalium, and Gfraptacme, but those 

species are ribbed throughout, or ribbed in the apical 

part.

Very small, circular apical fragments from localities 

138f and 173 are listed as D. (Laevidentalium} sp. They 

may represent D. pyrum or D. hay tense Gabb (Pilsbry 

and Sharp, 1898, p. 471, pi. 11, figs. 8,9; Woodring, 1925, 

p. 202, pi. 27, figs. 18-20; middle Miocene, Dominican 

Kepublic and Jamaica, respectively), which is circular,

or practically circular, throughout and has a simple 

apical orifice.

The age range of D. pyrum is late early to middle 

Miocene.

Occurrence: Lower, middle, and upper parts of Gatun 

formation (middle Miocene). Lower part, locality 138f 

(D. (Laevidentalium) sp.) ; middle part, western area, 

localities 161, 161c, 162, 162a, 170a (identification 

doubtful); upper part, eastern area, locality 173 

(D. (Laevidentalium) sp.). Thomonde formation 

(early Miocene), Haiti (USGS 9945 (identification 

doubtful), 9946). Cercado formation (middle Miocene), 

Dominican Kepublic (USGS 8737).

Subgenus Episiphon Pilsbry and Sharp

Pilsbry and Sharp, Manual of conchology, v. 17, p. 117, 1897. 

Type (logotype, Suter, Manual of the New Zealand Mollusca, 

p. 821, 1913) : Dentalium sowefbyi Guilding, living, North 

Carolina to West Indies.

Dentalium (Episiphon) innumerabile elassum Woodring, n. subsp. 

Plate 75, figure 26

Very small, very slender, barely increasing in diameter, barely curved, needle-like. Slightly compressed 

laterally, smooth. Base of broken pipe at apical orifice 

of type.

Length 5.5 mm, anterior diameter 0.6 mm, apical 

diameter outside pipe 0.4 mm (type).

Type :USNM 646738.

Type locality: 146 (USGS 5845, Quebrancha Hills 

overlooking Gatun Lake, 1.5 miles (2.4 km) northeast 

[east-southeast] of Gatun, Canal Zone), middle part of 

Gatun formation.

The type and a slightly larger specimen (length 

6 mm) of this small, excessively slender, needle-like 

Episiphon are from the Gatun formation. In outline it 

closely resembles the nominate subspecies (Pilsbry and 

Sharp (1897-98, p. 119, pi. 18, figs. 6-8, 1897; living, 

Baja California to Panama Bay), but is a third as large 

and more thick-shelled. As implied by the name, great 

numbers of the nominate subspecies were dredged by 

the Albatross not only in Panama Bay, where the type 

lot was dredged, but also off La Paz, Baja California.

A larger and more curved, needle-like species from 

the middle Miocene strata on Rio Banano, in southeastern Costa Rica (USGS 5882i), has fine, microscopic, 

closely spaced annular rings throughout its length. It 

is closely allied to Dentalium s&werbyi Guilding (Henderson, 1920, p. 77, pi. 13, figs. 2, 3, 10), the type of 

Episiphon.

Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle part, eastern area, locality 146; upper part, western area, locality 185.
486 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Family SIPHONODENTALIIDAE 

Genus Cadulus Philippi

Philippi, Enumeratio molluscorum Siciliae, v. 2, p. 209, 1844. 

Type (monotype) : Dentaliwm ovulum Philippi, living, Mediterranean Sea and eastern Atlantic Ocean.

Sub genus? 

Cadulus species

Small, moderately slender, slightly curved. Almost 

imperceptibly inflated at about a third of distance from 

broken anterior end. Apical end broken.

Length (broken at both ends) 5.1 mm, maximum diameter 0.8 mm, anterior diameter 0.7 mm, apical diameter 0.4 mm.

The affinities of this incomplete Cadulus from the 

Bohio formation of Barro Colorado Island are indeterminable.

Occurrence: Bohio formation (late Oligocene), locality 42d.

Subgenus Oadilopsis Woodring

Woodring, Carnegie Inst. Washington Pub. 366, p. 206,1925. 

Type (orthotype) : Ditrupa dentalina Guppy, Miocene, Jamaica.

Proposal of Gadilopsis was inspired by Pilsbry's 

treatment in his classic publication on scaphopods, prepared in collaboration with Sharp. It is a formal name 

for the "group of Cadulus dentalmus 1 "1 (Pilsbry and 

Sharp, 1897-98, p. 188, 1898). In simple apical orifice 

Gadilopsis resembles the subgenus Gadila, but the shell 

outline is different: needle-like, very slender, and the 

greatest inflation is close to the aperture. As noted by 

Pilsbry, his group includes species that are smooth, like 

Gadila, and species that are sculptured with fine annular 

rings [on the posterior part]. It may be added that the 

type species of Gadilopsis is sculptured or smooth. It 

would have been better to designate a living species 

as the type instead of a fossil species. Emerson (1962, 

p. 478; 1971, p. 79) rejected Gadilopsis as a synonym 

of Gadila.

Gadulus (Oadilopsis) dolichus Woodring, n. sp. 

Plate 70, figure 7

Large for the subgenus, slender, slightly curved, very 

slowly enlarging in diameter. Greatest diameter close 

to aperture, which is oblique to axis of shell. Surface 

smooth and polished. Microscopic, closely and regularly 

spaced growth lines parallel to oblique aperture. Irregularly outlined, faintly colored, alternating light and 

dark bands parallel to aperture on one specimen. Apical 

orifice simple, at least at diameter of 0.6 mm.

Length 11.8 mm, maximum diameter 1.2 mm, apertural diameter 0.9 mm, apical diameter 0.6 mm (type).

Type: USNM 646689.

Type locality: 41b (USGS 18839, East side of Palenquilla Point, head of cove north of triangulation station

and southwest of Corozo Island, Canal Zone), marine 

member of Bohio (?) formation.

Cadulus doliclws, from the marine member of the 

Bohio (?) formation at Palenquilla Point, is large, but 

not as large as the more slender and more strongly 

curved C. elegantissimus Pilsbry and Sharp (1898, p. 

473, pi. 11, figs. 28-30; middle Miocene, Dominican 

Eepublic), which reaches a length of 14 mm. The type 

is complete, or practically complete. So is a slightly 

smaller specimen, broken in handling, that shows faint 

color bands. A still smaller specimen and two fragments 

also are available. Though all these shells were encased 

in hard calcareous sandstone and are replaced by calcite, their surface is exceptionally well preserved.

Occurrence: Marine member of Bohio(?) formation 

(late Eocene), locality 41b.

Cadulus (Gadilopsis) species

Very small, very slender, slightly curved. Greatest 

diameter at slight inflation near aperture. Faint traces 

of what may be annular rings on apical part of some 

specimens. Apical orifice simple.

Length 4.5 mm, greatest diameter 0.7 mm, apertural 

diameter 0.5 mm, apical diameter 0.2 mm.

Six specimens of a small Cadulus were found in the 

marine member of the Bohio (?) formation on Trinidad 

Island. Most of the replaced shell material is corroded. 

This species is left unnamed, as these fossils are poorly 

preserved. It is a likely predecessor of the late Tertiary 

and living species of Gadilopsis, which are equally slender, but are larger and more inflated near the aperture.

This species and C. dolichus are the earliest known 

species of Gadilopsis.

Occurrence: Marine member of Bohio (?) formation 

(late Eocene), locality 42.

Cadulus (Oadilopsis) dentalinus (Guppy) 

Plate 75, figures 10, 11

Ditrupa dentalina, Guppy, Sci. Assoc. Trinidad Proc., v. 2, no. 2, 

p. 87, 1867 (Miocene, Jamaica) ; reprint, Bull. American 

Paleontology, v. 8, no. 35, p. 71, 1921, Guppy, Geol. Magazine, decade 2, v. 1, p. 445, pi. 16, fig. 11 (an unrecognizable 

illustration), 1874. Guppy, Geol. Magazine, decade 2, v. 2, 

p. 42, 1875 (Miocene, Jamaica). Guppy, Geol. Soc. London 

Quart. Jour., v. 32, p. 532, 1876 (Miocene, Dominican 

Republic).

Cadulus dentalinus (Guppy), Pilsbry and Sharp, Manual of Conchology, v. 17, p. 190, pi. 36, figs. 21, 22, 1898, assigned to 

section Gadila (Oligocene [Miocene], Jamaica). Pilsbry, 

Acad. Nat. Sci. Philadelphia Proc., v. 63, p. 168, 1911 (Oligocene [Miocene], Jamaica).

Cadulus (Gadilopsis) dentalinus (Guppy), Woodring, Carnegie 

Inst. Washington Pub. 366, p. 206, pi. 28, figs. 2, 3, 1925 

(Miocene, Jamaica).

?Cadulus (Gadila) aff. alHcomatus Ball, Toula, K. k. Geol. 

Reichsanstalt Jahrb., v. 61, p. 497, pi. 31, fig. 9, 1911 

(Miocene, Canal Zone).
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLEIDAE 487

Cadulus (Gadila) spiniformis Gardner, U.S. Geol. Survey Prof. 

Paper 142, p. 630, pi. 62, fig. 19, 1947, assigned to section 

Gadilopsis (Miocene, Florida).

Small, very slender, needle-like, curvature moderate. 

Greatest inflation near slightly oblique aperture, generally strong, exceptionally moderate. Surface generally 

smooth. Irregularly spaced, exaggerated growth lines 

generally present on apical part; exceptionally replaced 

by weak, closely spaced annular rings. Faint, narrow, 

brownish bands, parallel to aperture, visible on some 

shells. Apical orifice simple.

Height 8.4 mm, maximum diameter 1.2 mm, apertural 

diameter 0.7 mm, apical diameter 0.3 mm (larger figured 

specimen).

Type material: Lectotype, herewith designated, 

USNM 115607 (the syntype illustrated by Woodring, 

see synonymy).

Type locality: Bowden, Jamaica, Bowden formation.

Cadulus dentalinus is widespread in the middle and 

upper parts of the Gatun formation and is locally abundant in the middle part, especially at locality 147b, 

where several hundred specimens were collected. A 

slight range of variation in the degree of slenderness and 

in the strength of the inflation near the aperture is apparent. Only a few shells, one of which is illustrated 

(pi. 75, fig. 10), show distinct apical sculpture, whereas 

on Jamaican shells such sculpture is almost invariably 

present and extends over a larger part of the shell. 

C. spiniformis closely resembles Gatun shells that lack 

apical sculpture.

An exceptionally large Jamaican specimen (length 10 

mm) was named C. hendersoni (Woodring, 1925, p. 207, 

pi. 28, fig. 4). It should be treated as a form of C. 

dentalinus. Whether it is a subspecies or an infrasubspecific form is indeterminable. The Bowden molluscan 

fauna is a death assemblage swept up from many 

environments.

C. dentalinus is closely related to C. acus Dall (Henderson, 1920, p. 140, pi. 20, figs. 11,13; living, southern 

Florida, western Gulf of Mexico, West Indies) and C. 

perpusillus (Sowerby) (Emerson, 1971), also known as 

C. panamensis Pilsbry and Sharp (1897-98, p. 191, pi. 

36, figs. 23-25,1898; living, Baja California and Gulf of 

California to Panama). Both living species are apically 

sculptured. They run a little smaller than C. dentalinus, 

and 0. acus is not as strongly inflated near the aperture 

as the other two.

Occurrence: Middle and upper parts of Gatun f ormation (middle Miocene). Middle part, eastern area, localities 139b, 139c, 139g, 146, 147b, 147f, 147g, 147h, 151, 

155, 159d; western area, localities 161,169. Upper part, 

eastern area, localities 172, 173a, 175, 177b; western 

area, locality 183. Bowden formation (middle Miocene),

Jamaica. (Gurabo formation (middle Miocene), 

Dominican Republic (USGS 8714). Shoal River formation (middle Miocene), Florida.

Subgenus Platyschides Henderson 

Henderson, U.S. Natl. Mus. Bull. Ill, p. 104, 1920. 

Type (orthotype) : Cadulus grandis Verrill, living, Massachusetts 

to North Carolina.

Cadulus (Platyschides) epetrion Woodring, n. sp. 

Plate 75, figures 3, 2

Small, slender, slightly curved. 6radilopsis-\\k& in outline, greatest diameter at slight inflation near slightly 

oblique aperture. Surface smooth; faintly colored, alternating light and dark bands parallel to aperture 

on some specimens. Apex cut by four narrow, shallow 

notches.

Length 8 mm, maximum diameter 1.3 mm, apertural 

diameter 1 mm, apical diameter 0.4 mm (type).

Type: USNM 646741; paratype USNM 646732.

Type locality: 139c (USGS 22018, East side of road 

leading from Transisthmian Highway to refinery site 

on Payardi Island, Panama; about 100 meters southwest of refinery gate), middle part of Gatun formation.

Cadulus epetrion is widespread and locally abundant 

in the lower part of the Gatun formation and in strata 

near the base of the middle part, but was found at 

higher horizons at only three localities.

Were it not for the apertural features, this species 

would be assigned to the subgenus Gadilopsis. The 

paratype (pi. 75, fig. 2) and six other shells, among 

hundreds, show the apical notches, or at least some of 

them, but many others have ragged apical edges. C. 

annulatus Pilsbry (1911, p. 168; Woodring, 1925, p. 

207, pi. 28, figs. 5, 6; middle Miocene, Jamaica), incorrectly assigned to Polyschides in 1925, has a less pronounced inflation near the aperture and is sculptured 

with very fine annular rings.

Occurrence: Lower, middle, and upper parts of 

Gatun formation (middle Miocene). Lower part, localities 136a, 137, 138, 138a, 138b, 138c, 138d, 138e, 138f. 

Middle part, eastern area, localities 139b, 139c, 139d, 

139e, 139f, 139g, 155c. Upper part, eastern area, localities 177b, 178.

Cadulus (Platyschides) bushii Dall

Plate 75, figures 3, 4

Cadulus (carolinensis var.?) busMi Dall, Harvard Coll., Mus. 

Comp. Zoology Bull., v. 18, p. 430, 1889 (living, Barbados). 

Cadulus carolinensis bushii Dall, Pilsbry and Sharp, Manual of 

conchology, v. 17, p. 153, pi. 33, fig. 59,1898, assigned to subgenus PolyscMdes (living, Barbados).

Cadulus (Platyschides) bushii Dall, Henderson, U. S. Natl. 

Mus. Bull. Ill, p. 125, pi. 19, fig. 10, 1920 (living, Barbados).

Small, moderately curved, moderately inflated, greatest inflation at about anterior third. Apex slightly com-
488 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

pressed dorsoventrally. Surface smooth, polished. Apex 

cut by four narrow, shallow notches.

Length 7 mm, maximum diameter 1.2 mm, apertural 

diameter 0.8 mm, apical diameter 0.4 mm (slender illustrated specimen).

Type :USNM 95376.

Type locality: Barbados, living.

Though it was not found in the lower part of the 

Gatun formation, Cadulus bushii is widespread in the 

middle part and in the upper part in the eastern area. It 

was abundant in the construction-period fresh cuts on 

the Panama Railroad southeast of Gatun. Like C. 

dentalinus, several hundred specimens are in the collection from locality 147b. Six specimens from various 

localities show some, or all, of the apical notches.

Slight variation, shown by the illustrations, affects 

the degree of inflation. The slender form (pi. 75, fig. 3) 

closely resembles the type and other TJSNM species 

from the type region, dredged at depths of 35 to 100 

fathoms.

Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle part, eastern area, localities 139b, 146, 147b, 147f, 147g, 147h, 151, 153,153a, 

155; western area, localities 161,161c, 169,170a. Upper 

part, eastern area, localities 163, 175, 177, 177c. Living, 

Barbados.

PELECYPODS

Family NTTCTTLIDAE 

Genus Nucula Lamarck

Lamarck, Soc. Histoire Nat. Paris Mem., p. 87,1799. 

Type (monotype) : Area nucleus Linne, living, eastern North 

Atlantic Ocean and Mediterranean Sea.

The representation of this ubiquitous genus is meager.

Subgenus Nucula s.s.

Nucula (Nucula) cf. N. spheniopsis Conrad 

Plate 70, figures 11, 12

Small, trigonal, short, high, decidedly inequilateral. 

Sculpture consisting of narrow crowded concentric 

rugae, faintly undulated by indistinct radial threads. 

Hinge defective. Inner ventral margin crenulate.

Length 4.3 mm, height 4 mm, approximate diameter 

2 mm (larger figured specimen).

The moderately deep-water facies of the Caimito formation on Barro Colorado Island yielded four specimens of this small, trigonal Nucula. The larger illustrated specimen shows the outline, but the outer shell 

layer is missing. The exterior is shown by the smaller 

illustrated shell, the smallest in the lot, although it is 

not entirely free of sandy matrix.

The outline and sculpture suggest alliance to a larger 

species (length 6.5 mm) that occurs in the early Oligocene Red Bluff clay of Mississippi. Red Bluff specimens

in the Aldrich collection were identified by him as N. 

spheniopsis Conrad (Harris, in Harris and Palmer, 

1946-47, p. 63, pi. 14, figs. 24-30,1946). Though the outline of that late Eocene species is variable, the Caimito 

and Red Bluff fossils are less inequilateral.

Occurrence: Caimito formation (late Oligocene), localities 54h, 54n.

Nucula (Nucula) cf. N. cahuitensis Olsson 

Plate 75, figure 9

Minute, elongate, moderately inequilateral. Sculpture 

of main part of shell consisting of narrow, crowded 

rugae, minutely reticulated by radial riblets, which are 

indistinct in spaces between rugae. Anterior dorsal part 

set off by abrupt change in sculpture: rugae wider and 

fewer than on main part of shell, perpendicular to 

dorsal margin. Similar, but more crowded, rugae on 

depressed posterior dorsal part. Thirteen anterior teeth 

and five posterior. Ventral margin not preserved.

Length 1.7 mm, height (incomplete) 1.2 mm, diameter 0.4 mm (figured specimen).

The illustrated minute right valve, nicked along the 

ventral margin, is the only Nucula from the middle 

part of the Gatun formation. It is more elongate than 

the middle Miocene Costa Rican N. cahuitensis (Olsson, 

1922, p. 171, pi. 18, figs. 21-24), which has a subtrigonal outline. Like the species, the Gatun fossil has 

strongly discrepant dorsal sculpture. In that respect 

both species, as pointed out by Olsson for N. cahuitensis, 

are similar to the larger living eastern Pacific N. exigua 

Sowerby (Olsson, 1961, p. 56, pi. 1, figs. 2, 2a, 2b, 10, 

lOa). N. vieta Guppy (June, 1969, p. 316, pi. 13, figs. 

4-7; Matura formation, Trinidad) and the probably 

synonymous N. venezuelana Weisbord (1964, p. 36, pi. 1, 

figs. 1-6; Mare and Playa Grande formations, Venezuela), both of early Pliocene age, are the last allies of 

N. exigua in the present Caribbean region.

Occurrence: Middle part of Gatun formation (middle 

Miocene), eastern area, locality 139c.

Nucula (Nucula) tenuisculpta Gabb 

Plate 75, figure 8

Nucula tenuisculpta Gabb, Am. Philos. Soc. Trans., n. ser., v. 15, 

p. 255, 1873 (Miocene, Dominican Republic). Maury, Bull. 

Am. Paleontology, v. 5, no. 29, p. 161, pi. 26, fig. 8, 1917 

(Miocene, Dominican Republic). Pilsbry, Acad. Nat. Sci. 

Philadelphia Proc., v. 73, p. 401, pi. 38, fig. 6, 1922 (Miocene, 

Dominican Republic). Olsson, Bull. Am. Paleontology, v. 9, 

no. 39, p. 172, pi. 18, fig. 25, 1922 (Miocene, Costa Rica).

Very small, height a little less than length, very inequilateral. Microscopic radial sculpture (really hidden sculpture) very faint, not affecting surface profile, 

absent on parts of shell. Concentric sculpture limited 

to a few exaggerated growth lines. Eleven teeth in an-
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALLEIDAE 489

terior series and six in posterior. Inner ventral margin 

crenulate.

Length 3 mm, height 2.7 mm, diameter 0.8 mm (figured specimen).

Type: Acad. Nat. Sci. Philadelphia 2656.

Type locality: Dominican Republic, Miocene.

Three valves and a paired shell of a very small faintly 

sculptured Nucula, from the upper part of the Gatun 

formation in the eastern area, are identified as N. tenuisculpta. The illustrated right valve is the only one that 

is undamaged, aside from a slight posterior nick.

In the Dominican Republic N. tenuisculpta is abundant in the Cercado formation at USGS locality 8525. 

The sculpture is variable. Some shells are practically 

smooth, although at least some hidden microscopic 

radial sculpture is apparent. Concentric sculpture is 

irregular or absent. Both sets of sculpture are exaggerated in Pilsbry's drawing. No specimen in USNM 

collections is as large as the type (length 3.3 mm). The 

Gatun fossils are slightly more inequilateral than those 

from the Dominican Republic. A valve from the middle 

Miocene deposits in southeastern Costa Rica (USGS 

5882g), like that from the same area illustrated by 

Olsson, has very faint hidden sculpture on part of the 

shell.

Occurrence: Upper part of Gatun formation (middle Miocene), eastern area, localities 177b, 177c. Cercado 

formation (middle Miocene), Dominican Republic. 

Middle Miocene deposits, southeastern Costa Rica.

Genus Ennucula Ire dale

Iredale, Australian Mus. Records, v. 18, p. 202, 1931. 

Type (orthotype, p. 231) : Nuoula obliqua Lamarck, living, 

Australia.

The type of the type species was illustrated by 

Schenck (1934, p. 37, pi. 3, figs. 4a, 4b).

Subgenus Lissanucula Woodring, n. name

Nuculopsis Woodring, Carnegie Inst. Washington Pub. 366, 

p. 14, 1925. Not Nuculopsis Girty, 1911, or Rollier, 1912.

Type (orthotype) : Nucula (Nuculopsis) Mill Woodring, Miocene, Jamaica.

Of medium size, ovate, moderately inequilateral. Dorsal areas not depressed. Sculpture consisting of strong, 

closely spaced concentric rugae. Chondrophore moderately long, narrowly spoon-shaped, its axis slightly 

oblique to anterior tooth series. Inner ventral margin 

smooth.

Inasmuch as no records of any nuculids closely related to Nucula hitti have been found, it seems appropriate to propose a substitute name for Nuculopsis, a 

junior homonym on two counts, although no allies of 

that species are represented in the Panama faunas. 

Since it was first photographed, the type of N. hilli was

damaged and repaired at some unknown time. The 

repairing is satisfactory, except that the distal end of 

the chondrophore is missing.

As emphasized by Van de Poel (1955), the nuculids 

that have a smooth inner ventral margin differ in shell 

structure from those that have a crenulate margin. On 

that basis he classified the nuculids, aside from Acila, 

under two genera, Nucula and Nuculoma, and grouped 

other named taxa as subgenera. (Nuculoma Cossmann, 

1907, is the oldest name for the smooth group. For citation, description, and illustrations of Nuculoma and 

other forms that have a smooth inner ventral margin, 

see Schenck, 1934, p. 26-41).

Lissanucula is most similar to Ennucula. The type of 

Ennucula, however, lacks concentric sculpture other 

than growth lines; the posterior dorsal part is depressed; and the chondrophore is longer, slightly increasing in diameter, and its axis is not as oblique to the 

anterior tooth series.

Hertlein and Strong (1940, p. 383-384) speculated as 

to whether Nucolopsis or Nuculopsis was intended in 

1925, although the question could have been resolved 

unequivocally by an appeal to the author of the name. 

In the main heading the spelling is Nucolopsis, but in 

the species heading and discussions it is Nuculopsis. 

They settled for Nucolopsis, which in the original account was an unfortunate typographic error.

Nucula (Nucolopsis} schencki Hertlein and Strong 

(1940, p. 384, pi. 1, figs. 8-10; living, Port Guatulco, 

Oaxaca, Mexico) is not related to N. hilli. It is a minute 

species, or immature specimen, of Nucula s.s.

Genus Acila H. and A. Adams 

H. and A. Adams, The genera of Recent Mollusca, v. 2, p. 545,

1858. 

Type (logotype, Stoliczka, India Geol. Survey Mem., Palaeontologia Indica, Cretaceous fauna of southern India, v. 3, p.

XXI, 1870, p. 325, 1871) : Nucula divaricata Hinds, living,

western Pacific Ocean.

Two poorly preserved fossils from the Culebra formation are listed as Acila sp.

Subgenus Acila s.s. 

Acila (Acila) isthmica isthmica (Brown and Pilsbry)

Plate 70, figure 4, plate 71, figure 15, plate 76, figures 1-3, 6, 

plate 82, figure 2

Nucula (Acila) isthmica Brown and Pilsbry, Acad. Nat. Sci.

Philadelphia Proc. v. 63, p. 361, pi. 27, figs. 11, 12, 1911

(Miocene, Canal Zone). 

Acila (Acila) isthmica (Brown and Pilsbry), Schenck, Eclogae

Geol. Helvetiae, v. 28, p. 503, 1936 (Miocene, Colombia).

Schenck, Geol. Soc. America Spec. Paper 4, p. 87, pi. 13, figs.

1, 3, 5, 6, 1936 (Miocene, Columbia).

Of medium size, asymmetrically trigonal, posterior 

dorsal area depressed. Posterior end weakly rostrate, 

sinus setting off rostrum very shallow and extending
490 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

only short distance from ventral margin. Primary divarication roughly median, secondary divarication rare. 

Ribs closely or moderately closely spaced, faintly to distinctly irregularly noded. Ribs on anterior dorsal area 

fewer and wider than on main part of shell, ending perpendicular to dorsal margin. Similar, but more closely 

spaced, ribs on depressed posterior dorsal area. Twentytwo to 24 feet in anterior series, 9 to 11 in posterior. Innermost posterior tooth on right or left valve longer 

than others. Chondrophore wide, short, Inner ventral 

margin crenulate.

Dimensions: See following table.

Type: Acad. Nat. Sci. Philadelphia 1742. Now lost or 

misplaced, missing as early as 1964.

Type locality: Gatun Locks excavation, Canal Zone, 

middle part of Gatun formation.

Occurrence of Acila (Acila) isthmica isthmica and dimensions 

in mm of largest specimens

Age

Late 

Miocene

Middle 

Miocene

Early 

Miocene

Late 

Oligocene

Formation

Charges sandstone

Gatun formation

Upper part, 

western area

Upper part, 

eastern area

Middle part, 

eastern area

La Boca formation

Caimito formation

Number 

of 

specimens

11

39

4

2

22

10

Dimensions of 

largest specimen

Length

21.9

22.8

17.3

18

24

17

Height

17.5

18.5

13

13

17

14

As shown by the preceding table, Acila isthmica 

isthmica, which is the only Acila s.s. in the present Caribbean region, has an age range of late Oligocene to late 

Miocene. It presumably has its roots in the Pacific 

Ocean. A. isthmica burica Olsson (1942, p. 25, pi. 1, 

figs. 2, 6, 8, 9; Charco Azul formation, southwestern 

Costa Rica) survived later than the nominate subspecies. It is considerably larger than the nominate subspecies (length up to 31.5 mm). In the area under study, 

however, no relation between size and age in A. isthmica 

isthmica is apparent.

All of the Caimito specimens were collected from the 

moderately deep-water facies on Barro Colorado Island. 

That illustrated (pi. TO, fig. 4) does not show the weak 

rostrum and the accompanying shallow, short sinus, 

as the extreme posterior end is missing. Much of the 

shell is missing on the illustrated large La Boca fossil 

(pi. 71, fig. 15). Though the species was based on two

valves from the middle part of the Gatun formation, 

none is in some 60 collections from that part under 

study. The ribs on one of 30 shells from the upper part 

of the Gatun in the western area, shown on pi. 76, figs. 

3,6, are more widely spaced than on others. The discrepant dorsal sculpture duplicates that of N. cahuitensis 

and its allies.

Occurrence: Caimito formation (late Oligocene) 

localities 54k, 541, 54m, 54n. La Boca formation (early 

Miocene), localities lOli, 125, 127, 127b, 128. Middle 

and upper parts of Gatun formation (middle Miocene). 

Middle part, eastern area, Gatun Locks excavation 

(Brown and Pilsbry's record). Upper part, eastern 

area, localities 171, 173, I77b; western area, localities 

179, 183. Chagres sandstone (late Miocene), localities 

198, 203, 206, 208. Las Perdices shale (early Miocene), 

Colombia. Middle Miocene deposits, Darien area, 

Panama (USGS 8452, fragments, identification doubtful); southeastern Costa Rica (USGS 5883f); 

Venezuela (Schenck's record).

Family NTrCTTLANTDAE 

Genus Jupiteria Bellardi

Bellardi, Mongrafia delle Nuculidi trovate finora nei terreni 

terziari del Piemonte e della Liguria, p. 20, Torina, 1875.

Type (logotype, Ball, Wagner Free Inst. Sci. Trans., v. 3, pt. 

4, p. 579, 1898) : Leda concava (Bronn) (Nucula concava 

Bronn), Miocene and Pliocene, Italy.

The importance of the shape of the chondrophore in 

classifying nuculanids was emphasized by Stewart 

(1930, p. 51-55). The chondrophore of Jupiteria, and 

also of Saccella (the following genus), is triangular 

and symmetrical. In addition, the species of Jupiteria 

are small, short, equilateral or moderately inequilateral, 

more or less corbuloid, bluntly rostrate, and concentrically sculptured, but the sculpture is weak or of 

moderate strength.

Jupiteria aipeia Woodring, n. sp. 

Plate 72, figures 5, 9

Small, high and short to moderately elongate, bluntly 

rostrate. Dorsal areas very narrow, bearing only growth 

lines. Both areas set off by change in sculpture, posterior 

area more depressed than anterior. Concentric rugae 

moderately strong, closely spaced, uniform where not 

corroded. Chondrophore and hinge not exposed.

Length 8.6 mm, height 6.2 mm, diameter 3 mm (type).

Type :USNM 646703.

Type locality: 54h (USGS 18841, Barro Colorado 

Island, western part of island, mouth of first stream 

north of Zetek House, Canal Zone), Caimito formation.

Thirteen specimens of Jupiteria aipeia were found 

in the moderately deep-water f acies of the Caimito formation on Barro Colorado Island. An immature left 

valve is more elongate than the others (length 7 mm,
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLEIDAE 491

height 4.2 mm, locality 54k). The outline is similar to 

that of the Miocene Italian /. brocchii (Bellardi) 

(Sacco, 1898, p. 57, pi. 12, figs. 6-10), but the sculpture 

of the Canal Zone species is stronger.

Occurrence: Caimito formation (late Oligocene), localities 54h, 54k.

Jupiteria subtumida (Woodring)? 

Plate 75, figures 17, 22

Very small, moderately elongate, moderately inequilateral, bluntly rostrate. Dorsal areas not differentiated. 

Sculpture consisting of fine, crowded growth lines, 

slightly exaggerated here and there, and subdued on 

parts of shell. Chondrophore triangular. About 12 teeth 

in anterior and posterior series.

Length 3.4 mm, height 2.4 mm, diameter 1.1 mm 

(figured specimen).

The upper part of the Gatun formation in the Mount 

Hope area yielded three very small valves of Jupiteria, 

two of which probably were originally paired. They 

presumably are immature. They have the outline of the 

Miocene Jamaican /. subtumida (Woodring, 1925, p. 

19, pi. 1, figs. 13, 14). The umbos of that species show 

faint traces of fine growth lines. At a later stage mature 

shells (length 6.5 mm) are coarsely and irregularly 

sculptured.

In American fossil species of Jupiteria have been recognized in Jamaica and the Canal Zone. Leda solida 

Dall (1881, p. 126; on dubious grounds renamed Leda 

solidifacta Dall, 1886, p. 252, pi. 7, figs. 7a, 7b), the sole 

surviving American species, is larger and more corbuloid than the fossils (length 9.7 mm). It was recognized 

by Dall as similar to /. concava. The type, dredged off 

Bahia Honda, Cuba, depth 287 fathoms, is the only 

specimen in USNM collections.

Occurrence: Upper part of Gatun formation (middle 

Miocene), eastern area, localities I77c, I77d.

Genus Saccella Woodring

Woodring, Carnegie Inst. Washington Pub. 366, p. 15, 1925. Substitute name for Ledina Sacco, December, 1898, not Ledina 

Dall, October, 1898.

Type (orthotype of Ledma Sacco) : Ledina fragilis (Chemnitz) 

(Area frayilis Chemnitz )=Nucula commutata Philippi= 

Lembulus deltoideus Risso, living, Mediterranean Sea.

Stewart (1930, p. 55) pointed out that it is unfortunate in fact, he could have written inexcusable that 

"a species having a distinct type specimen was not selected as the type species" for this widespread genus; 

that is, it is unfortunate that /Saccella was not proposed 

as a new subgenus, rather than as a substitute name for 

Ledina Sacco, with a type species that has the above 

specification. Stewart went to great length in an attempt 

to fix the earliest available name for Area, fragilis* a

name that appeared in a publication that is nomenclatorially unavailable. He came to the conclusion that 

Lembulus deltoideus is the earliest name.

The species of Saccella are similar to those of Jupiteria, but are strongly rostrate and generally are 

strongly sculptured. Whether Saccella is to be treated 

as a genus or as a subgenus of Jupiteria is debatable.

Group of Saccella acuta

The following five species (possibly except the first, 

which is imperfectly known) are more or less similar to 

Saccella acuta (Conrad) (1831-33, p. 32, unnumbered 

pi., fig. 3,1832; Dall, 1886, p. 251, pi. 7, figs. 3a, 3b, 8). 

Many names have been proposed for nuculanids of the 

group of S. acuta, 20 in the Tertiary Caribbean province alone, ranging in age from Paleocene to Pliocene. 

All are strongly rostrate, and a sharp ridge limits the 

rostrum. Those features and the shape of the triangular, 

symmetrical chondrophore are not repeated in the 

descriptions.

Poorly preserved fossils from the Culebra and 

La Boca formations, perhaps not the same species, are 

listed as Saccella sp. (fine sculpture).

Saccella species

The collection from leached sandstone of the Gatuncillo formation capping Cerro Pelado (altitude 223 m), 

1 km north-northwest of Gamboa, includes an internal 

mold of a small right valve of Saccella. It is moderately 

elongate, subequilateral, and rostrate. Impressions of 

the hinge teeth are preserved. The exterior mold was 

not recovered.

Length 7.5 mm, height 4 mm.

An incomplete external mold of a larger right valve 

(estimated restored length 13 mm) in the same collection may possibly represent the same species. It shows 

concentric rugae, but the posterior part is missing.

Occurrence: Gatuncillo formation (middle(?) Eocene) , locality 37a.

Saccella phlyctaena Woodring, n. sp. 

Plate 70, figures 8,15,16

Moderately small, moderately elongate, moderately 

inequilateral. Shallow anterior groove present or absent, or represented by faint ridge corresponding to 

anterior border of groove. Posterior dorsal area moderately wide, sculptured with threads slightly oblique to 

dorsal margin, fewer than rugae on rostral ridge. Anterior dorsal area very narrow, sharply limited, bearing low, short pustules oblique to dorsal margin, fewer 

than rugae beyond area. Concentric rugae strong, uniform, spacing of moderate width. Chondrophore and 

hinge not exposed.
492 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Length 11 mm, height 6.5 mm, diameter 2.4 mm 

(type).

Type: USNM 646690.

Type locality: 40d (USGS 6028a, Vamos Vamos, 

lower bed, Canal Zone), marine member of Bohio(?) 

formation.

Saccella phlyctaena occurs in the three regions where 

the marine member of the Bohio(?) formation was 

found. Whether the anterior dorsal area is consistently 

pustular is not known, as many of the some 40 specimens 

do not show the area.

Among the species of the group of 8. acuta in the 

faunas under study, this late Eocene species is most 

similar to S. acuta, which has been living in western 

Atlantic waters since Miocene time. The rugae of S. 

acuta, however, are slightly more closely spaced and 

its anterior dorsal area is not pustular. 8. phlyctaena 

evidently is more closely related to the living eastern 

Pacific S. acapulcensis (Pilsbry and Lowe) (Olsson, 

1961, p. 65, pi. 2, figs. 8, 8a), which has a pustular 

anterior dorsal area. The fossils may be distinguished by 

their slightly finer concentric rugae.

The poorly preserved type of 8. incognita (Guppy) 

(1867, p. 501, fig. 1; Eocene, Trinidad) the only specimen is small and elongate (length 7.7 mm, height 

4.4 mm). Guppy later (1882, p. 172, pi. 7, fig. 9) 

thought it was 8. packardi (Forbes) (1848, p. 566, figs. 

2, 3; 1848a, p. 348, figs. 2, 3; Eocene, Barbados), which, 

according to Forbes' illustrations, is short and high.

Occurrence: Marine member of Bohio(?) formation 

(late Eocene), localities 40, 40d, 40e, 41, 41b, 42, 42c.

Saccella cf. S. subcerata (Woodring) 

Plate 71, figures 2, 3

Small, elongate, moderately inequilateral. Posterior 

dorsal area moderately wide, sculptured with threads 

slightly oblique to dorsal margin, fewer than rugae on 

rostral ridge. Anterior dorsal area very narrow, sculptured with closely spaced continuations of rugae beyond 

area. Concentric rugae moderately strong, not entirely 

uniform, closely spaced. Chondrophore and hinge not 

exposed.

Length 7 mm, height 4 mm, diameter 2 mm (figured 

specimen).

This species occurs in the moderately deep-water 

facies of the Oaimito formation on Barro Colorado Island. It remotely resembles Saccella subcerata (Woodring, 1925, p. 17, pi. 1, figs. 6, 7; Miocene, Jamaica), but 

is more strongly rostrate. Though it may be a new species, a better sample than the three specimens now available is needed to justify a name.

The rugae are more or less corroded on two of these 

fossils and are corroded also on the central part of that

illustrated. Despite the missing extreme posterior end, it 

can be seen that the illustrated right valve is faintly 

birostrate, a feature not shown by the other two.

Occurrence: Caimito formation (late Oligocene), localities 54k, 54m.

Saccella acrita epacra Woodring, n. subsp. 

Plate 75, figures 18-21, 27, 29, 30

Very small, elongate, moderately inequilateral. Shallow anterior groove generally present, low ridge on anterior side of groove generally stronger than that on posterior side. Posterior dorsal area very wide, sculptured 

with crowded threads slightly oblique to dorsal margin, 

continuous with rugae on posterior ridge. Anterior dorsal area very narrow; low, short pustules, oblique to dorsal margin, present or absent. Concentric rugae generally strong, generally closely spaced, exceptionally 

moderately coarse, exceptionally subdued. Fourteen to 

18 teeth in anterior series, 12 to 17 in posterior.

Length 5.6 mm, height 3.1 mm, diameter (both 

valves) 2.7 mm (type). Length 6.6 mm, height 3.9 mm, 

diameter 2.2 mm (largest figured specimen).

Type: USNM 646747.

Type locality: 147g (USGS 5899, Highest fossil-bearing beds, Quebrancha Hills, % mi. (1.2 km) out from 

Gatun, Canal Zone), middle part of Gatun formation.

Saccella acrita epacra is the most abundant and most 

variable, as well as the smallest, Saceella in the Gatun 

formation. Some 500 specimens are in collections from 

the three parts of the formation, but none from the 

upper part in the eastern area. Minute, immature 

shells, down to a length of 0.8 mm, are fairly common.

The degree of elongation, the absence or presence and 

distinctness of the anterior groove, the absence or presence of pustules on the anterior dorsal area, and the 

strength, width, and spacing of the rugae are variable. 

The prevailing outline and sculpture in the middle part 

of the Gatun are represented by the type (pi. 75, figs. 19, 

21). Rugae of intermediate spacing and a strong ridge 

on the anterior side of the shallow anterior groove are 

shown on plate 75, figure 27, and subdued rugae on plate 

75, figure 20. Though a considerable range of variation 

in sculpture, including moderately coarse rugae, is 

shown by some 60 specimens in a middle Gatun collection (locality 169), moderately coarse sculpture is noteworthy among shells from the lower part of the formation and from strata near the base of the middle part 

(pi. 75, fig. 30).

The consistently wider posterior dorsal area distinguishes the fossils from 8. acrita acrita (Dall, 1908, p. 

374), which was dredged in great numbers by the Albatross in Panama Bay and off La Paz, Baja California, at 

depths of 10 to 29 fathoms. Though the type lot of several hundred specimens shows variation in subduing of
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLETDAE 493

the fine sculpture and its absence on parts of the shell, 

the two faintly sculptured syntypes illustrated by Keen 

(1958, p. 20, fig. 16; 1971, p. 29, fig. 19) are not typical. 

Stronger sculpture, comparable to that of most of the 

Gatun fossils, is prevalent in the northern parts of the 

range, as shown by Olsson's illustration (1961, p. 60, pi. 

2, fig. 7) of a shell dredged off Baja California. Pustules 

were not observed on the anterior dorsal area of living 

shells, but they are present or absent on the fossils.

An unrecorded small Saccella in the middle Miocene 

deposits of southeastern Costa Kica (USGS 5882g and 

other localities on Bio Banano) has a somewhat narrower posterior dorsal area than the Gatun fossils and 

therefore is more similar to S. acrita acrita.

Small forms of Saccella, related to S. acrita, in the 

Alum Bluff group of Florida are overnamed. S. canonica 

(Ball, 1890-1903, p. 591, 1898; Gardner, 1926-47, p. 16, 

pi. 3, figs. 15-17, 1926; Chipola formation), which typically has exceptionally fine sculpture, is the oldest name. 

The type, a minute, immature valve (length 2.5 mm, fig. 

16 of Gardner's illustrations) by itself, without the 

available growth series of topotypes, is unrecognizable.

Occurrence: Lower, middle, and upper part of Gatun 

formation (middle Miocene). Lower part, localities 136a 

(identification doubtful), 138a, 138c, 138d. Middle part, 

eastern area, localities 139b, 139c, 139d, 139e, 139f, 139g, 

146, 147b, 147e, 147f, 147g, 147h, 158, 159d; western 

area localities 161d, 166, 169. Upper part, western area, 

locality 185. Middle Miocene deposits, Darien area, 

Panama (USGS 8477).

Saccella cf. S. ornata (d'Orbigny;

Moderately small, moderately to distinctly elongate, 

moderately inequilateral. Posterior dorsal area moderately wide, sculptured with threads slightly oblique to 

dorsal margin. Anterior dorsal area very narrow, set 

off by subdued sculpture. Concentric rugae strong, narrow, closely spaced, uniform, but generally subdued on 

rostral ridge. Chondrophore and hinge not exposed.

Length 8.6 mm, height 5.2 mm, diameter 2.4 mm 

(most nearly complete specimen).

Eight valves from the Chagres sandstone are identified as Saccella cf. S. ornata. All of them are in poor 

condition. In outline and sculpture the most nearly complete specimen closely resembles that species as it occurs 

in the Esmeraldas formation of Ecuador (Olsson, 1964, 

p. 21, pi. 1, fig. 12), but is larger and lacks an anterior 

groove. Though other Chagres shells are more elongate 

than that mentioned, none shows an anterior groove.

S. ornata occurs also in the Pliocene of Ecuador and 

is living along the coast of Ecuador and Peru (Olsson, 

1961, p. 60, pi. 2, figs. 3, 3a).

Occurrence: Chagres sandstone (late Miocene), 

localities 206, 206b.

Group of elongate species

An elongate species, represented in the La Boca formation by poorly preserved specimens, is listed as Saccella sp. (elongate).

Saccella cf. S. fabalis (Olsson) 

Plate 77, figures 10, 16

Very small, very elongate, subequilateral, strongly 

rostrate. Posterior dorsal area narrow, sculptured with 

weak threads slightly oblique to dorsal margin. Anterior dorsal area very narrow, sculptured with subdued continuation of rugae, oblique to dorsal margin. 

Concentric rugae strong, widely spaced, dorsal face 

concave; narrower and slightly insinuated by slight 

depression on ventral side of rostral ridge. Hinge not 

completely exposed.

Length 5.2 mm, height 2.5 mm, diameter 1.2 mm 

(figured specimen).

This evidently is a new species, but it is represented 

by a single specimen, which may be immature. In a 

general way it may be compared with Saccella fabalis 

(Olsson, 1964, p. 22, pi. 1, fig. 11; middle Miocene, Ecuador) , which is twice as large and has more closely spaced 

rugae that are not slightly insinuated on the ventral side 

of the rostral ridge.

Occurrence: Middle part of Gatun formation (middle 

Miocene), western area, locality 169.

Group of large species 

Saccella aff. S. balboae (Brown and Pilsbry)

Poorly preserved fossils from the Culebra and La 

Boca formations have the outline and sculpture of Saccella balboae, the following species. They presumably 

represent that species or a closely allied predecessor. 

The estimated maximum length is about 16 mm.

Occurrence: Culebra formation (early Miocene), locality 108c. La Boca formation (early Miocene), localities 99c, lOOb, lOli.

Saccella balboae (Brown and Pilsbry) 

Plate 77, figures 9,11,19, 20, 23

Leda balboae Brown and Pilsbry, Acad. Nat. Sci. Philadelphia

Proc., v. 63, p. 362, pi. 27, fig. 8,1911 (Miocene, Canal Zone).

Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 173, pi. 18, fig.

15,1922 (Miocene, Costa Rica). 

?Leda sp., Toula, K. k. Geol. Reichsanstalt Jahrb., v. 58, p. 719,

pi. 27, fig. 2,1909 (Miocene, Canal Zone).

Moderately large, high, subequilateral, strongly 

rostrate. Shallow anterior groove present or absent. 

Posterior dorsal area wide, sculptured with threads 

slightly oblique to dorsal margin, more or less continuous with rugae on rostral ridge. Anterior dorsal area 

very narrow, set off by low short pustules, practically
494 GEOLOGY AND PALEONTOLOGY OP CANAL ZONE

perpendicular to dorsal margin, or area not distinguishable. Concentric rugae strong, spacing of moderate 

width, dorsal face concave. Eighteen to 20 teeth in anterior series, 13 or 14 in posterior.

Length 19.6 mm, height 11.4 mm, diameter 8 mm 

(larger figured specimen).

Type: Acad. Nat. Sci. Philadelphia 1743 (larger of 

two specimens, as designated by Brown and Pilsbry).

Type locality: Gatun Locks excavation, Canal Zone 

middle part of Gatun formation.

Though Saccella ~balboae is widespread in the three 

parts of the Gatun formation, only three of some 70 

specimens, one of which is illustrated (pi. 77, figs. 9, 

23), are large. None of the three, however, is as large 

as the type (length 22.1 mm). In fact, immature shells, 

even to a minimum length of 1.1 mm, are common. Their 

coarser sculpture distinguishes them from immature 

shells of /S. acrita epacra, with which they are associated 

at seven localities.

The sculpture is uniform, except that the rugae of a 

small right valve (length 8.2 mm), the only specimen 

from locality 185, are more closely spaced than on the 

others. Pustules on the anterior dorsal area, like those 

shown on plate 77, figure 11, were observed on shells 

from the lower part of the Gatun that show the area, 

but on none from the middle and upper parts. The 

presence or absence of pustules on shells of /S. acrita 

epacra is devoid of stratigraph'ic significance.

/S. balboae is related to S. peruviana (Dall) (1890^ 

1903, p. 579,1898; Leda acuminata Nelson, 1870, p. 20'5, 

pi. 7, fig. 8, not Nucula [Leda] acuminata von Buch, 

1838; not Leda peruviana Dall, 1908, p. 377), a late 

Miocene species from Peru, and to S. davidana (Olsson) 

(1942, p. 28, pi. 1, fig. 3), an early Pliocene species from 

southwestern Panama. Both are a little larger (length 

25 and 27 mm, respectively), and the rugae of S. peruviana are slightly more closely spaced and those of 

S. davidana slightly coarser. The living eastern Pacific 

S. fastigata (Keen) (Olsson, 1961, p. 62, pi. 2, figs. 2,2a, 

pi. 3, fig. 9) is still larger (length 34 mm) and more 

coarsely sculptured than S. balboae. No comparable 

species has been found in western Atlantic waters.

Occurrence: Lower, middle, and upper parts of 

Gatun formation (middle Miocene). Lower part, localities 136,137,138,138a, 138c, 138d, 138e. Middle part, 

eastern area, localities 147b, 147f, 147g, 152, 153,153a; 

western area, locality 161a. Upper part, eastern area, 

localities 171,172,173,173a 174,175,177; western area, 

localities 183, 185. Middle Miocene deposits, southeastern Costa Rica.

Genus Adrana H. and A. Adams 

H. and A. Adams, the genera of Recent Mollusca, v. 2, p. 547,

1858.

Type (logotype, Stoliczka, India Geol. Survey Mem., Palaeontologia Indica, Cretaceous fauna of southern India, v. 3, 

p. XX, 1870, p. 820, 1871) : Nucula, lanceolata Lamarck, 

1819, not Nucula lanceolata, 3. Sowerfoy, 1917, = Leda, 

ta-ylori Hanley, living, Pacific coast of Guatemala.

Adrana stena Woodring, n. sp. 

PTaJte 70, figure 17

Large, slightly inequilateral, umbonal area slightly 

angulating dorsal margin. Anterior ventral margin 

broadly rounded, posterior ventral margin slightly insinuated. Posterior dorsal area narrow, set off by sharp 

carina. Anterior dorsal area very narrow, set off by suppression of sculpture and a weak carina. Entire shell, 

except dorsal areas, sculptured with narrow, closely 

spaced rugae, more closely spaced in umbonal area (absent on somewhat worn tips of umbos), somewhat 

coarser on and near posterior dorsal carina. Hinge not 

exposed.

Length (not quite complete) 48.5 mm, height 11.4 

mm, diameter (both valves) 5.5 mm (type).

Type :USNM 646693.

Type locality: 42d (TJSGS 18837, Barro Colorado Island, northern part of inland, stream heading west of 

Miller Trail near Miller 17, 'about 100 meters above 

mouth, Canal Zone), Bohio formation.

The type is the largest and most nearly complete of 

10 specimens found in the Bohio formation of Barro 

Colorado Island. Shell material is missing on part of 

posterior end of the left valve of the type, and the 

posterior tip is also missing.

Adrana stena is most similar to A. crenifera 

(Sowerby) (Olsson, 1961, p. 70, pi. 3, figs. 4, 4a, 4b), 

now living in eastern Pacific waters. The Bohio fossils 

are a little larger and lack a strong 'carina setting off 

the anterior dorsal 'area.

Fragmentary remains from the Culefora arid La Boca 

formations may represent A. stena, but are so poorly 

preserved that they are listed as Adrana sp. An incomplete external mold from the middle part of the Gatun 

formation (loc. 161d), comparable in size to A. stena, 

is also listed as Adrana sp.

Occurrence: Bohio formation (late Oligocene), 

localities 42d, 42g.

Adrana cf. A. newcombi (Angas)

Very small, very elongate, decidedly inequilateral, 

umbo at about anterior third of length. Umbonal area 

slightly angulatiing dorsal margin. Posterior dorsal area 

narrow, limited by a carina. Anterior dorsal area very 

narrow, weaMy set off by subdued carina. Sculpture of 

n'arrow, closely spaced rugae limited to umbonal area 

and anterior dorsal part of shell, or to as much as anterior half. Faint scales present or absent on posterior 

dorsal carina. Hinge not exposed.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALLE1DAE 495

Length 14 mm, height 3.7 mm, diameter (both valves) 

1.3 mm.

The description is 'based on three defective, small 

specimens from the middle part of the Gatun formation. In outline they are similar to immature valves of 

the living Caribbean Adrana newcombi. The sculpture 

of the living shells is finer and covers a larger part of 

the shell, all except about the posterior third or less, 

and the posterior dorsal carina is weaker and consistently lacks scales.

Treatment of three other defective, small, Gatun fossils is unresolvable without additional material. The 

anterior two-thirds of a right valve (loc. 139b) bears 

relatively 'coarse, widely spaced rugae. A posterior fragment of a left valve (loc. 138c) has relatively strong 

scales on the anterior part of the posterior dorsal carina 

and subdued scales on the remainder. It is associated 

- with an anterior fragment of a different left valve that 

shows faint scales on the extreme anterior part of the 

posterior dorsal carina. All these fossils are listed as 

Adrana sp.

Altena (1968) recently pointed out that Leda 

(Adrana) newcombi Angas (1878, p. 314, pi. 18, figs. 

16, 17), dredged in Navy Bay, Aspinwall that is, 

Limon Bay, Colon, of present terminology at a depth 

of eight fathoms, has many years precedence over 

YoUia perprotracta Dall (1912, p. 1; 1925, p. 32, pi. 18, 

fig. 3). Ball's name was based on fossils collected from 

the informally named Atlantic muck at USGS locality 

5850, near Mount Hope. The muck, formerly considered 

to be of Pleistocene age, is now known to have been deposited during the postglacial rise of sea level (p. 326 

of chapter D). A. newcombi is living on the coast of 

Panama in the Colon area and at Bocas del Toro Island, 

at an unspecified Cuban locality, and on the west and 

southwest coasts of Puerto Rico.

A late Miocene and early Pliocene species of Adrana 

from Trinidad has been doubtfully identified as 

A. perprotracta (Jung, 1969, p. 323, pi. 14, figs. 3, 4).

Occurrence: Middle part of Gatun formation (middle 

Miocene), eastern area, locality 158; western area, locality 161c.

Genus Portlandia Morch 

Morch, Prodromus faunae molluscorum Gronlandiae, p. 21,

Copenhagen, 1857. 

Type (Opinion 769, Internat. Comm. Zoological Nomenclature,

1966) : Nucula arctica Gray, living, Arctic and Boreal

provinces.

Subgenus Portlandella Stewart? 

Stewart, Acad. Nat. Sci. Philadelphia Special Pub. 3, p. 61,

1930. 

Type (orthotype) : Leda rosa M. A. Hanna, middle Eocene,

California.

Portlandia (Portlandella?) euthynta Woodring, n. sp. 

Plate 70, figure 14

Of medium size, moderately elongate, moderately inequilateral. Anterior dorsal margin slightly convex, 

posterior dorsal margin slightly concave at umbo, 

straight and slightly sloping from there to posterior 

end. Anterior and ventral margins rounded. Posterior 

margin curved and ascending steeply. Posterior dorsal 

area very narrow, lying between weak carinae, dorsal 

one wider and higher than ventral. Faint pustules, 

oblique to dorsal margin, visible in area and on ventral 

carina. Anterior dorsal area very narrow, faint pustules 

on ventral weak carina. Ventral middle part of shell 

sculptured with weak, closely spaced rugae. Chondrophore and hinge not exposed.

Length 13 mm, height 7.2 mm, diameter 2 mm (type).

Type :USNM 646694.

Type locality: 42i (USGS 18845, Barro Colorado 

Island, eastern part of island, stream east of Shannon 

Trail, about 365 meters southeast of Shannon 1, Canal 

Zone), Bohio formation.

An attempt to expose the chondrophore and hinge 

runs the risk of damaging the single specimen of this 

species from the Bohio formation of Barro Colorado 

Island. No species closely comparable to it has come to 

my attention, and subgeneric assignment is questionable. 

Alliance to Portlandella is suggested by the nonsinuate 

posterior ventral margin. The posterior dorsal margin 

of the type species of Portlandella, however, is more 

concave, the shell is more inflated, and sculpture other 

than growth lines is absent.

The posterior ventral margin of the living eastern 

Pacific Yoldia martyria Dall (1897, p. 9, pi. 2, fig. 15) 

is slightly insinuated, producing a subrostrate outline. 

The sinuation and rostration are not as pronounced as in 

Portlandia s.s., and the chondrophore is wider and 

shallower than that of Portlandia s.s. The type locality 

of Ball's species is off San Pedro Martir Island, in the 

Gulf of California, but it has a remarkable northward 

range to Prince of Wales Island, Alaska, at depths of 30 

to 135 fathoms (65 fathoms at the type locality). No 

lots are in U'SNM collections between northern Oregon 

and the type locality.

Occurrence: Bohio formation (late Oliogocene), locality 42i.

Family ARCIDAE

Subfamily ARCINAE 

Genus Area Linne

Linn<5, Systema naturae, 10th ed., p. 693,1758.

Type (Internat. Comm. Zoological Nomenclature, Opinion 189,

1945) : Area noae Linn£, living, Mediterranean Sea and

eastern Atlantic Ocean.
496 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Area imbricata Bruguiere 

Plate 73, figure 2, Plate 77, figure 17

Area imbricata Bruguiere, Encyclopedie methodique, v. 1, p. 98, 

1789 (living, "mer des In des, sur les c6tes du cap de Bonne 

Esperance"). Gabb, Am. Philos. Soc., Trans., n. ser., v. 15, 

p. 254, 1873 (Miocene, Dominican Republic). Gabb, Philadelphia Acad. Nat. Sci. Jour., 2nd ser., v. 8, p. 378, 1881 

(Pliocene, Costa Rica).

Area (Area) imbricata Bruguiere, Weisbord, Bull. Am. Paleontology, v. 45, no. 204, p. 54, pi. 3, figs. 1-8, 1964 (Pleistocene, living, Venezuela; additional citations). Jung. Bull. 

Am. Paleontology, v. 55, no. 247, p. 326, pi. 14, figs. 7, 8, 1969 

(Pliocene, Trinidad).

Area umbonata Lamarck, Histoire naturelle des animaux sans 

vertebres, v. 6, p. 37, 1819 (living, Jamaica). Maury, Bull. 

Am. Paleontology, v. 5, no. 29, p. 163, pi. 30, fig. 11, 1917 

(Miocene, Dominican Republic). Maury, New York Acad. 

Sci., Scientific Survey of Porto Rico and Virgin Islands, 

v. 3, pt. 1, p. 6, 1920 (Oligocene, Miocene, Puerto Rico). 

Pilsbry, Acad. Nat. Sci. Philadelphia Proc., v. 73, p. 403,1922 

(Miocene, Dominican Republic). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 182, pi. 22, fig. 2, 1922 (Miocene, Costa 

Rica). Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 35, 

pi. 3, fig. 6, pi. 8, fig. 4, 1925 (Pliocene, living, Trinidad). 

Ferreira, Mus. Paraense Emilio Goeldi Bol., n. ser., Geol., 

no. 9, p. 12, pi. 1,1964 (Miocene, Brazil).

Area (Area) umbonata Lamarck, Jung, Bull. Am. Paleontology, 

v. 49, no. 223, p. 420, pi. 51, figs. 2, 4, 1965 (Miocene, 

Venezuela).

Area (Area) umbonata morantensis Woodring, Carnegie Inst. 

Washington Pub. 366, p. 30, pi. 2, figs. 10, 11, 1925 (Miocene, 

Jamaica).

Area umbonata paezensis H. K. Hodson, Bull. Am. Paleontology, 

v. 13, no. 49, p. 3, pi. 1, fig. 7, 1927 ("Quaternary," 

Venezuela).

Small or of medium size, subrectangular except for 

posterior elongation, posterior angulation strong, byssal 

gape slight. Radial ribs relatively wide and widely 

spaced on posterior slope, narrow and closely spaced on 

. remainder of shell. Eibs imbricated by irregularly 

spaced concentric grooves. Ligament area long and 

moderately wide, a pair of subumbonal ligament 

grooves on small shell from Gatun formation.

Length 27.7 mm, height 16.5 mm, diameter 10.8 mm 

(figured specimen from lower member of Alhajuela 

formation). Length 16.4 mm, height 9.9 mm, diameter 

4.9 mm (figured specimen from Gatun formation).

Type: Unknown.

Type locality: Presumably Caribbean region, living.

The representation of this long-lived and far-ranging 

species is meager: a poorly preserved right valve of 

medium size from the lower member of the Alhajuela 

formation and a nicked small right valve from the 

lower part of the Gatun formation. The Alhajuela 

fossil, extracted from marly limestone at a now submerged locality on Rio Chagres above the present 

Madden Dam, was identified by Dall as Area umbonata, 

when it was received from MacDonald in 1911. Though

the ventral margin is imperfect, a growth line shows 

a slight byssal insinuation. Living shells reach a length 

of 85 mm, but the largest of Miocene age so far recorded 

is half as large.

The posterior angulation of the Gatun specimen is 

stronger than that of the small shells from Bowden, 

Jamaica, which were named A. umbonata morantensis. 

That name is to be suppressed.

Occurrence: Lower member of Alhajuela formation 

(early Miocene), locality 76. Lower part of Gatun formation (middle Miocene), locality 138e. San Sebastian 

formation (late Oligocene), Puerto Rico. Tampa limestone (early Miocene), Florida. Aymamon limestone 

(early Miocene), Puerto Rico. Pirabas formation (early 

Miocene), Brazil. Chipola formation (early Miocene), 

Florida. Cercado formation (middle Miocene), Dominican Republic. Bowden formation (middle Miocene), 

Jamaica. Deposits of middle Miocene 'age, Costa Rica. 

Cantaure formation (middle Miocene), Venezuela. Oak 

Grove sand member of Shoal River formation (middle 

Miocene), Florida. Limon formation (late Miocene), 

Costa Rica. Matura formation iand Courbaril member 

of Morne 1'Enfer formation (early Pliocene), Trinidad. 

Moin formation (late Pliocene), Costa Rica. Living, 

North Carolina to Parana, Brazil.

Genus Barbatia Gray

Gray, Synopsis of the contents of the British Museum, 44th ed., 

Mollusks, p. 81, 1842 (genus without species).

Type (monotype, Gray, Zool. Soc. London Proc., p. 197, 1847) : 

Area barbata Linne, living, Mediterranean Sea and eastern Atlantic Ocean.

Submenus Barbatia s.s. 

Barbatia (Barbatia) cf. B. cancellaria (Lamarck)

The genus Barbatia is represented by a poorly preserved specimen from the shallow-water facies of the 

Caimito formation and 11 specimens, also poorly preserved, from the La Boca formation. The moderate size 

(maximum length about 45 mm), relatively fine ribbing, 

especially on the posterior slope, and lack of distortion 

suggest alliance to B. cancellaria, now living in the Caribbean region, rather than to B. Candida, also living 

there.

B. Candida has a long Caribbean record, 'beginning in 

early Miocene time. The alleged five species of Barbatia 

from Bowden, Jamaica (Woodring, 1925, p. 34-36), including three based on very immature valves, are to be 

suppressed as B. Candida. In other words, Dall was justified in identifying B. Candida at Bowden (Dall, 1890- 

1903, p. 626, 1898).

Occurrence: Caimito formation (late Oligocene), 

locality 55b. La Boca formation (early Miocene), localities 99a (Barbatia^ sp.), 99g, 114,115a, 116a.
GASTROPODS, SCAFHOFOD8, PELBCYPODS: NUCTJLIDAE TO MALLEIDAE 497

Genus Calloarca Gray

Gray, Annals and Mag. Nat. History, 2nd ser., v. 19, p. 369, 1857. 

Type (monotype) : B[arbatia] alternata (Sowerby) [Byssoarca 

alternata], living, tropical eastern Pacific Ocean.

Subgenus Taeniarca Olsson

Olsson, Neogene mollusks from northwestern Ecuador, Paleontological Research Inst., p. 25, 1964. 

Type (orthotype) : Barbatia (Calloarca) taeniata Dall \_Barl)aUa (Cucullaria) taeniata], Pliocene, Florida.

Calloarca s.s. evidently is monotypic. Taeniarca lacks 

the carinat© posterior ridge of Calloarca s.s. and the 

coarse ribs on the posterior slope of that subgenus. It 

embraces the three Miocene and Pliocene species from 

Florida assigned to Calloarca by Keinhart (1935, p. 23) 

and the following species, which occurs in the Gatun 

formation as well as in the middle Miocene of Ecuador.

Calloarca (Taeniarca) cachla Olsson

Plate 77, figure 7

Calloarca (Taeniarca) cachla Olsson, Neogene mollusks from 

northwestern Ecuador, Paleontological Research Inst., p. 25, 

pi. 3, fig. 9,1964 (Miocene, Ecuador).

Small, inflated, elongate, decidedly inaequilateral, 

umbonal area wide. Middle ventral margin slightly insinuated and corresponding part of shell above insinuation slightly depressed. Ribs low and flat; those on main 

part of shell narrow, closely spaced, basically bipartate 

(exceptionally tripartite, or even quadripartate); 

tihose on posterior rounded ridge slightly wider and undivided ; those between ridge and posterior dorsal margin narrow. Cardinal area narrow, hinge not preserved.

Length (incomplete) 21.5 mm (estimated restored 

length 25 mm), height 12.5 mm, diameter 10.5 mm 

(figured specimen).

Type :USNM 643853.

Type locality: Cueva de Angostura, Rio Santiago, 

Ecuador, Angostura formation.

Twelve valves from the middle part of the Gatun 

formation are identified as Calloarca cacJila. All, except 

three very small valves (loc. 169), are more or less 

corroded. The ribs on and near the posterior ridge 

of the single Ecuadorean valve are somewhat wider 

than those of the Gatun fossils.

The ribs of the Miocene species from Florida C. 

phalacra (Ball, 1890-1903, p. 626, pi. 33, fig. 3, 1898, 

Chipola formation and Oak Grove sand member of 

Shoal River formation) and C. leonensis (Mansfield, 

1932, p. 42, pi. 5, figs. 1, 3, 5, Mansfield's late Miocene 

Cancellaria zone) are so closely spaced that the space 

between them is hardly wider than the groove dividing 

the ribs into two parts. C. phalacra has not yet been 

illustrated in exterior view. C. taeniata (Dall, 1890-1903, 

p. 631, pi. 25, figs. 1, la, 1898; Caloosahatchee formation) , of Pliocene age, is the youngest known species and

is far larger than any of Miocene age (length 52 to 55 

mm). The large double-valve specimen illustrated by 

Dall in his figure 1 is herewith designated the lectotype. 

Dall evidently instructed McConnell to reconstruct 

from smaller isolated left valves the interior view of 

figure la.

Occurrence: Middle part of Gatun formation (middle Miocene), eastern area, localities 146, 152; western 

area, localities 160, 169. Angostura formation (middle 

Miocene), Ecuador.

Genus Acar Gray

Gray, Annals and Mag. Nat. History, 2nd ser., v. 19, p. 369, 1857.

Type (logotype, Stoliczka, India Geol. Survey Mem., Palaeontologia Indica, Cretaceous fauna of southern India, v. 3, 

p. XXI, 1870) : B[arbatia] divaricata Sowerby [Byssoarca 

divaricata], living, western Pacific Ocean.

Stoliczka's type designation far antedates the 1925 

designation (Woodring, 1925, p. 37).

Acar domingensis (Lamarck) 

Plate 77, figures 4, 8

Area domingensis Lamarck, Histoire naturelle des animaux 

sans vertebres, v. 6, p. 40, 1819 (living, San Domingue).

Barbatia (Acar) domingensis (Lamarck), Woodring, Carnegie 

Inst. Washington Pub. 366, p. 37, pi. 3, figs. 17, 18, 1925 

(Miocene, Jamaica). Mansfield, Florida Dept. Conservation, 

Geol. Bull. 15, p. 199, pi. 10, fig. 13, 1937 (Miocene, Florida). 

Perrilliat Montoya, Mexico Univ. Nac., Inst. Geologia, Paleontologia Mexicana, no. 14, p. 5, pi. 1, figs. 3, 4, 1963 (Miocene, Mexico). Weisbord, Bull. Am. Paleontology, v. 45, 

no. 204, p. 61, pi. 4, figs. 1-9, 1964 (Pleistocene, living, Venezuela ). Jung, Bull. Am. Paleontology, v. 55, no. 247, p. 328, pi. 

15, figs. 1, 2, 1969 (Pliocene, Trinidad).

fBarbatia (Acar) sp. cf. B. (Acar) domingensis (Lamarck), 

Mansfield, Jour. Paleontology, v. 14, p. 175, pi. 25, fig. 11, 

1940 (Oligocene, Alabama).

Barbatia (Acar) reticulata (Gmelin), Dall, Wagner Free Inst. 

Sci., v. 3, pt. 4, p. 629, 1898 (Eocene to living, southeastern 

United States). Maury, Bull. Am. Paleontology, v. 5, no. 29, 

p. 166, pi. 30, fig. 16, 1917 (Miocene, Dominican Republic). 

Maury, New York Acad. Sci., Scientific Survey of Porto 

Rico and Virgin Islands, v. 3, pt. 1, p. 7, 1920 (Miocene, 

Puerto Rico). Hubbard, New York Acad. Sci., Scientific Survey of Porto Rico and Virgin Islands, v. 3, pt. 2, p. 106, 1920 

(Miocene, Puerto Rico). Maury, Bull. Am. Paleontology, 

v. 10, no. 42, p. 43, pi. 8, figs. 18, 21, 1925 (Pliocene, Trinidad ; living Venezuela).

Of medium size, inflated, subquadrate, decidedly inequilateral. Posterior slope sharply set off by reduction 

in strength of concentric ridges. Middle of ventral margin slightly insinuated. Sculpture coarsely reticulate; 

concentric ridges very coarse, widely spaced; radial 

threads narrower, more closely spaced, swollen on concentric ridges. Cardinal area narrow, a few ligament 

grooves on posterior part. Adductor muscle scars raised.

Length 18 mm, height 10.2 mm, diameter 4.8 mm 

(figured specimen).

475-796 O - 73 - 4
498 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Type: Unknown.

Type locality: Hispaniola, living.

Acar doming'ensis is represented by two valves (one 

in poor condition) from the middle part of the Gatun 

formation and probably by four poorly preserved, 

doubtfully identified valves from the La Boca formation. Though living shells have a length as great as 

34 mm, the length of the largest fossils so far recorded, 

or observed in USNM collections, is less than 21 mm.

On the Bermudan platform Bretsky (1967) found 

that A. domingensis is "attached by its byssus to the 

undersurfaces of corals and, less commonly, of rocks."

The descendants of the Miocene A. domingensis in 

the eastern Pacific Ocean are known as A. gradata 

(Broderip and Sowerby) (Olsson, 1961, p. 82, pi. 6, 

figs.6, 6a, 6b). Conchologically they are indistinguishable from the westsern Atlantic descendants. The slight 

hinge difference mentioned by Eeinhart (1939, p. 43) 

is by no means consistent. Heath (1941, p. 296), however, found that they are anatomically distinct.

Occurrence: La Boca formation (early Miocene; 

identification doubtful), localities 99f, 116a. Middle 

part of Gatun formation (middle Miocene), localities 

145, 160d. Chickasawhay limestone (late Oligocene), 

Alabama (identification doubtful). Tampa limestone 

(early Miocene), Florida. Thomonde formation (early 

Miocene), Haiti. Aymamon limestone (early Miocene), Puerto Rico. Ponce limestone (early Miocene), 

Puerto Rico. Chipola formation (early Miocene), Florida. Cercado and Gurabo formations (middle Miocene), 

Dominican Republic (Gurabo formation, USGS 8544). 

Bowden formation (middle Miocene), Jamaica. Agueguexquite formation (middle Miocene), Tehuantepec 

area, Mexico. Limon formation (late Miocene), Costa 

Rica. Caloosahatchee formation (early Pliocene), 

Florida. Matura formation (early Pliocene), Trinidad. 

Moin formation (late Pliocene), Costa Rica. Living, 

North Carolina to West Indies.

Subfamily ANADARINAE

As in other regions, anadarine arcids are abundant 

and highly diversified in the Tertiary Caribbean province. They range in length from 6 to 133 mm and in outline from narrowly elongate to subquadrate and to 

narrowly subtrigonal. Some 170 names have been proposed or used for Caribbean species of late Eocene to 

Pliocene age, all except 11 of which were based on 

Caribbean fossils. To be sure, some 30 are synonyms 

and perhaps others are. All except a few of the anadarines are the result of Miocene flowering.

A considerable percentage of Miocene Caribbean 

arcine species is still living: 50 percent of those in the 

present account. On the contrary, the percentage for

anadarine species is very low: not more than about 3, 

and less than 1 of those in the present account.

Genus Anadara Gray

Gray, Zool. Soc. London Proc., p. 198,1847.

Type (orthotype) : Area, antiquata Linn6, living, western Pacific 

and Indian Oceans.

The numerous fossil and living species of Anadara 

are difficult to classify satisfactorily. Nineteen names 

have been proposed for Anadara-lUke, species and perhaps others escaped the count. According to the grade 

of taxa adopted in the present report, they rate as 

subgenera, insofar as they are usable.

Dall (1890-1903, p. 617-619, 633-657,1898), who was 

influenced by the treatment adopted by Henry and Arthur Adams (1853-58, p. 537-538, 1857), assigned the 

American species to Scapharca (Gray, 1847, p. 198, 

Scapharea by error; type (orthotype) : Area inaequivalvis Bruguiere, living, Indian Ocean), as a subgenus 

of Area. As he adopted subdivisions (sections) under 

Scapharca, including Anadara, in headings the name 

Scapharca appears as a genus and his sections as subgenera. Following Dall's commanding lead, American 

paleontologists for many years used Scapharca for most 

of their anadarines.

Anadara and Scapharca appeared on the same page. 

It is irrelevant that Anadara immediately precedes 

Scapharca, but what is relevant is that the type species 

of Scapharca is an exceptional species. Anadara therefore is given precedence, as has been done tacitly by 

many paleontologists and zoologists. Area inaequivalvis 

is subquadrate, relatively thin-shelled, decidedly inequivalve, the left valve overlapping the right, and its ribs 

undivided. The cardinal area is microscopically striate 

vertically. Scapharca is rejected for American species, 

as was done by Olsson (1961, p. 87). Though some 

American species are inequivalve, that does not make 

them species of Scapharca.

The cardinal area of Area antiquata, described by 

Olsson (1961, p. 86) and H. E. Yokes (1969, p. 6), is 

vertically striate only, or combines the striae with shallow horizontal grooves, among which some short, generally slightly wavy, deeper grooves may be interspersed. Anadara s.s., like Scapharca, is rejected for 

American species, again as was done by Olsson (1961, 

p.86).

Subgenus Hawaiarca Dall, Bartsch, and Rehder 

Dall, Bartsch, and Rehder, Bernice P. Bishop Mus. Bull. 153, p.

27,1938. 

Type (orthotype) : Hawaiarca rectangula Dall, Bartsch, and

Rehder, living, Hawaii.

A noteworthy group of very small, elongate, early 

and middle Miocene Caribbean species, ranging in 

length from 7 to 11 mm, is doubtfully represented in the
GASTROPODS, SCAPHOPODS, PELE.CYPODS: NTJCULIDAE TO MALLEIDAE 499

faunas under consideration. This group includes Anadara guajatica (Sheldon and Maury) (Maury, 1920, p. 8, 

pi. 1, fig. 3; [Aymamon limestone], Puerto Kico), and 

the presumably synonymous A. cf. A. donacia (Dall) 

(Hubbard, 1920, p. 105, pi. 14, fig. 7, not fig. 6; Quebradillas [now Aymamon] limestone, Puerto Rico), a still 

unidentified species from the Thomonde formation of 

Haiti (USGS 9907, 9908), A. donacia (Dall) (Woodring, 1925, p. 48, pi. 5, figs. 8-11; Bowden formation, 

Jamaica), and A. cibaoica (Maury) (1917, p. 30, pi. 

19, fig. 20; Cercado and Gurabo formations, Dominican Republic). The umbo of these fossils is 

narrowly sulcate. On many a shallow depression, extending from the umbo to the middle of the ventral 

margin, slightly insinuates the margin. The ribs in 

the depression, or in a corresponding position in the 

event that the depression is absent, are slightly to distinctly narrower than on either side, and the interior 

fluting of the margin is reduced. The narrow cardinal 

area is smooth, although faint markings, vertical or 

horizontal, are visible on some valves. The depression 

is least distinct, or absent, on the Thomonde fossils and 

most distinct, and most generally present, on A. cibaoica. How many species are to be recognized, however, is 

questionable. A, cibaoica is represented by an estimated 

200 valves in USNM collections, and the Thomonde 

form and A. donacia by perhaps thousands. Five specimens of A. donacia, all immature, are articulated and 

show that the left valve is slightly larger than the 

right. They do not show a shallow depression or a gape, 

although the insinuation of the margin of many adult 

valves surely indicates a gape.

Through the generosity of my colleague Druid Wilson, it can be recorded that this group of species is represented, in late Miocene and Pliocene deposits in peninsular Florida, by a species larger (length up to 14.6 

mm) and less elongate than the Caribbean forms. On 

one of the late Miocene valves (USGS 23727) four narrow ligament grooves extend obliquely upward across 

the narrow posterior part of the cardinal area. The ligament presumably did not cover the short, wider anterior 

part.

The concept of Hawaiarca, as a subgenus of Anadara, 

may be extended to include these American species, although the ribs of the type species are strongly noded. 

The type species is slightly inequivalve and has a median ventral, narrow gape. In Japan Hawaiarca has an 

age range of Pliocene to the present time. (Noda, 1966, 

p. 75). The American species left no known descendants 

in American waters.

The Oligocene Belgian species Anadara sulcicosta 

(Nyst) (Schenck and Reinhart, 1938, p. 22, pi. 1, fig. 3, 

pi. 2, fig. 1) reaches a length of 33 mm. It has a sulcate

umbo and a slight median ventral gape. On account of 

the gape, Eames (1967) assigned the species to Barbatia, 

although it clearly is anadarine.

Many species of Anadara, both small and large, have 

a sulcate umbo, although the statement that it is found 

on every species examined, (Woodring, 1938, p. 30) 

means that the sampling was not extensive. The inference that the sulcate umbo indicates a median byssal 

gape at an early stage is confirmed by the life history of 

A, subcrenata, a Japanese species grown for food. On 

settling, the spat attaches itself to seaweed or some other 

object by a byssus; about a year after hatching, the 

attachment is abandoned and the animal buries in mud 

(Cahn, 1951, p. 37). On the contrary, A. granosa, also 

grown in Japan for food, has tightly closed valves even 

at an age of one month, when the length of the shell is 

about 2 mm (USNM 186586, hundreds of specimens).

Anadara (Hawaiarca?) species

Very small, elongate (height 56 percent of length), 

inequilateral (umbo at about anterior third of length). 

Umbo sulcate, shallow depression extending from sulcus 

toward ventral margin. Sculptured with about 29 

faintly noded ribs.

Length 6.6 mm, height 3.7 mm.

A poorly preserved left valve from the Culebra formation is almost entirely a mold. The size, sulcate umbo, 

and depression suggest Hawaiarca. It may, however, be 

an immature specimen of a species of Rasia.

Occurrence: Culebra formation (early Miocene), locality 102.

Subgenus Rasia Gray

Gray, Annals and Mag. Nat. History, 2nd ser., v. 19, p. 371, 1857. 

Type (logotype, Stewart, Acad. Nat. Sci. Philadelphia, Special 

Pub. 3, p. 86, 1980) : Area formosa Sowerby, living, eastern 

Pacific Ocean.

Rasia is the earliest unequivocal name for the bulk 

of the American anadarines characterized by tentshaped ligament grooves diverging at a wide angle. 

Gray's name was overlooked until attention was called 

to it by Stewart. The type species is elongate and its 

anterior ribs are divided. The status of Cora, introduced on the same page as Rasia, is uncertain. The type 

species, Area aviculoid.es Reeve, 1844 (avicularoides by 

error in Gray; not A. aviculoides deKoninck, 1842, 

=A. aviculaeformis Nyst, 1848), designated by Stewart 

on the same page as the designation for Rasia, has been 

held to be an immature specimen of A. formosa (Olsson, 1961, p. 90) and to be a valid eastern Pacific species 

(Rost, 1955, p. 202, pi. 14, figs. 21a-21c, 23). Even if 

it is a valid species, as interpreted by Rost, it falls 

within the concept of Rasia. In any event, Rasia is given 

precedence.

Other names have been proposed for more or less 

similar anadarines, differing in outline and ribbing.
500 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Diluvarca (Woodring, 1925, p. 40; type (orthotype) : 

Area diluvii Lamarck, Miocene to living, Mediterranean region), based on a misconception of Area antiquata and improperly assigned subgeneric rank under 

Barbatia, was repudiated a few years after it was proposed (Woodring, 1928, p. 18, footnote), but was resuscitated recently (Olsson, 1961, p. 87). The type species 

is of medium size, equivalve, moderately elongate, and 

its ribs are undivided. The type of Sectiarca (Olsson, 

1961, p. 97; type (orthotype) : Area floridana Conrad, 

living, Florida) is large, slightly inequivalve, elongate, 

and typically has divided ribs, except at the posterior 

end. The limits of these subgenera are vague.

For the present account the Caribbean anadarines 

assigned to Rasia are divided into four groups: (1) 

elongate (the group most similar in outline to the type 

species); (2) auriculate; (3) short; (4) subrounded. 

The group of elongate species is further divided into 

three subgroups based on size: small (length 6 to 30 

mm); medium (length 31 to 44 mm); and large (length 

45 to 117 mm).

In the following descriptions, if nothing is mentioned 

as to whether the shell is equivalve or inequivalve, it 

means that articulated shells, or valves that can be 

paired, are not available.

Group of elongate species

Subgroup of small species

Anadara (Rasia) oarmenensis Clark

Plate 70, figure 5

Anadara (Anadara) carmenensis Clark, in Clark and Durham, 

Geol. Soc. America Mem. 16, p. 51, pi. 2, fig. 3, 1946 (Eocene, 

Colombia).

Small, elongate (height 54 percent of length), moderately inequilateral (umbo a little behind anterior third 

of length). Sculptured with about 25 ribs, apparently 

all divided below umbonal region, except at posterior 

end. Cardinal area narrow, corroded.

Length 6.5 mm, height 3.5 mm (figured specimen).

Type: Calif ornia Acad. Sci. 7904.

Type locality: California Acad. Sci. 31694, 6 miles 

west of El Carmen, Bolivar, Colombia, deposits of late 

Eocene age.

Two small, presumably immature, valves from the 

marine member of the Bohio( ?) formation are identified as Anadara carmenensis. Though they are poorly 

preserved, the illustrated right valve has the outline and 

divided ribs of that species. The other specimen, a fragment of a left valve replaced by calcite, has strongly 

divided, faintly noded ribs.

In the type region A. carmenensis reaches a length of 

28 mm. The posterior end of the cardinal area of a rightvalve (length 13.6 mm) from the type region (USGS

11450) shows four closely spaced ligament grooves. The 

remainder of the area is corroded. No specimen from 

Colombia or the Canal Zone is well enough preserved 

to reveal whether the umbo is sulcate.

Occurrence: Marine member of Bohio(?) formation 

(late Eocene), locality 41b. Deposits of late Eocene age, 

Colombia.

Subgroup of species of medium size

Anadara (Rasia) dariensis progonica Woodring, n. subsp. 

Plate 71, figure 1

Of medium size, elongate (height 60 to 65 percent 

of length), inequilateral (umbo at about anterior third 

of length), left valve slightly larger than right. Sculptured with 28 to 31 faintly noded ribs, about as wide 

as space between them. Ribs apparently not divided, or 

faintly to distinctly divided, generally only on anterior 

and posterior ends, exceptionally on practically entire 

shell, especially near ventral margin. Space between 

ribs bearing closely spaced concentric threads, exaggerated at irregularly spaced intervals. Cardinal area 

inaccessible or corroded.

Length 24.6 mm, height 14.9 mm, diameter (both 

valves) 11.8 mm (type). Length 31 mm, height 19.2 

mm, diameter (both valves) 15 mm (largest specimen).

Type :USNM 646705.

Type locality: 112 (USGS 16910, West side of Gaillard cut, canal station 1759, about 30 meters southwest 

of edge of canal, basal part of bed 13 of section on p. 

35, Canal Zone), Culebra formation.

Anadara dariensis progonica is a small predecessor of 

the nominate subspecies. In addition to being consistently smaller, some, including the type, have divided 

ribs on practically the entire shell: a feature observed 

on only eight of some 800 specimens of the nominate 

subspecies. Though the type is an articulated specimen, 

only the right valve is well preserved. Left valves of 

the nominate subspecies are more strongly noded than 

those of A. dariensis progonica.

This small subspecies is fairly common in the Culebra 

and La Boca formations (72 and 28 specimens, respectively), and is identified also in a collection from a submerged locality on Rio Chagres at the former site of 

Las Cruces, upstream from Gamboa. The largest number was found in the transition zone between the Culebra and Cucaracha formations (localities 110, Ilia, 112, 

112a). Thirteen shells from the Culebra and two from 

the La Boca are articulated. None of these fossils is well 

enough preserved to show whether the umbo is sulcate.

Many are poorly preserved, but on some the effect of 

undivided ril?s on any part of the shell apparently is 

not the result of preservation. If so, it is another feature 

distinguishing the two subspecies.
GASTROPODS, SCAPHOPODS, PELEiCYPODS: NUCULIDAE TO MALLEIDAE 501

Fragmentary remains in carbonaceous shale near the 

base of the Cucaracha formation (loc. 122) are listed as 

Anadara sp.

Occurrence: Culebra formation (early Miocene), localities 106, 109 (Anadara sp.), 110, llOa, Ilia, lllb, 

112, 112a). La Boca formation (early Miocene), localities 99b, 99c, 99d, lOlh, 115b. Deposits of early Miocene 

age at Las Graces, locality 94.

Anadara (Basia) dariensis dariensis (Brown and Pilsbry) 

Plate 77, figure 3, 5, 13, 18, 21, 22, 24

Area dariensis Brown and Pilsbry, Acad. Nat. Sci. Philadelphia Proc., v. 63, p. 362, pi. 22, fig. 10, 1911 (Miocene, Canal 

Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. 184 

(assigned to subgenus Scapharca), pi. 22, figs. 10-13, 1922 

(Miocene, Canal Zone, Panama). Li, Geol. Soc. China Bull., 

v. 9, p. 252, pi. 1, figs. 3, 3a, 1930 (Miocene, Canal Zone).

ScapJiarca (Scapharca) dariensis (Brown and Pilsbry), Maury, 

Bull. Am. Paleontology, v. 10, no. 42, p. 55, pi. 6, fig. 5, 

1925 (Miocene, Canal Zone).

Area (Scapharca) dariensis Brown and Pilsbry, Anderson, California Acad. Sci. Proc., 4th ser., v. 18, no. 4, p. 147, 1929 

(Miocene, Colombia).

Area (Diluvarca) dariensis Brown and Pilsbry, Olsson, Bull. 

Am. Paleontology, v. 19, no. 68, p. 68, 1932 (Miocene, Peru).

Anadara (Scapharca) dariensis (Brown and Pilsbry), Oinomikado, Geol. Soc. Japan Jour., v. 46, p. 627, pi. 29, fig. 26, 

1939 (Miocene, Colombia). Diaz de Gamero, Univ. Central 

Venezuela, Escuela Geol., Minas, Metaliirgica, Geos, no. 17, 

p. 34,1968 (Miocene, Venezuela).

Not Area dariensis Brown and Pilsbry, Hubbard, New York 

Acad. Sci., Scientific Survey of Porto Rico and Virgin Is< 

lands, v. 3, pt. 2, p. 105, pi. 14, fig. 5, 1920 (Oligocene, 

Puerto Rico).

Area gatunensis Toula, K. k. Geol. Reichsanstalt Jahrb., v. 61, 

p. 493, pi. 30, fig. 4, 1911 (Miocene, Canal Zone).

Scapharca losquemadica Maury, Bull. Am. Paleontology, v. 5, 

no. 29, p. 173, pi. 30, fig. 1, 1917 (Miocene, Dominican 

Republic).

fArca cf. consobrina Moore, Toula, K. k. Geol. Reichsanstalt 

Jahrb., v. 58, p. 717, pi. 27, fig. 1, 1909 (Miocene, Canal 

Zone).

fArca (Anadara) diluvii Lamarck, Toula, K. k. Geol. Reichsanstalt Jahrb., v. 58, p. 718, 1909 (Miocene, Canal Zone).

Of medium size, elongate (height 60 to 67 percent of 

length, exceptionally 56 percent), inequilateral (umbo 

at about anterior third of length). Left valve decidedly 

larger than right. Umbo of smallest valves, and of well 

preserved larger valves, faintly to distinctly sulcate, 

especially on left valves. Sculptured with 27 to 33 ribs 

(generally 30 to 33). On both valves anterior and posterior ribs divided, except one or two adjoining anterior 

dorsal margin and as many as five adjoining posterior 

dorsal margin. Anterior ribs more widely spaced than 

posterior and divided by wide, shallow depression; 

posterior ribs by narrow groove. With eight exceptions 

among some 860 specimens, ribs on remainder of shell 

undivided; those on left valve strongly noded and wider 

than smooth or weakly noded ribs of right valve. Both

branches of divided ribs noded, nodes stronger on anterior ribs than on posterior. Space between ribs bearing 

concentric threads of irregular strength and spacing, 

more conspicuous in wide spaces of right valve. Cardinal area narrow; one to four (generally two or three) 

paired ligament grooves and one or two (generally one) 

additional posterior limbs.

Length 36.3 mm, height 22 mm, diameter 9.1 mm 

(lectotype). Length 42.3 mm, height 24.6 mm, diameter 

11.4 mm (largest specimen, figured).

Type material: Lectotype, herewith designated, right 

valve figured by Brown and Pilsbry, Acad. Nat. Sci. 

Phila. 1744.

Type locality: Gatun Locks excavation, Canal Zone, 

middle part of Gatun formation.

Anadara dariensis dariensis, which was well described 

by Brown and Pilsbry, is widespread and locally abundant throughout the Gatun formation, but less so in the 

upper part than in the other two. It is represented by 

some 860 specimens, ranging in length from 2 to 41.5 

mm, 42 of which are articulated.

As shown by the illustrations, a considerable range 

of variation in the ratio of height to length is apparent. 

Variation affects also to some extent the degree of inflation. The most notable variation, however, is shown 

by eight valves that have divided median ribs: one 

from locality 138f, five from 139c, one from 146, and 

one from 183. Both right and left valves are affected, 

but on the five right valves and one left the ribs are 

divided only near the ventral margin. On two left valves 

the division extends some distance from the margin 

(pi. 77, figs. 3, 5). That shown on plate 77, figure 3 is 

remarkable, as it is the most elongate of the some 860 

specimens.

As usual, locality 147b is notable for the large number 

of minute shells: 29 under 4 mm. The length of the 

largest specimens in the three parts of the Gatun is 

shown in the following table:

Length of largest specimens of Anadara dariensis dariensis

Qatun formation

Upper part. ....... _ _...... __ .... __ . _ . ........

Middle part _ . _ .......... _ ...... _ ____ . __ .

Lower part.... .................. _ .._....... _ .......

Number of 

specimens

24

399

444

Length in mm 

of largest 

specimen

41.5

42.3

36.5

This anadarine has no allies in present western 

Atlantic waters. It is closely allied, however, to the 

eastern Pacific A. concinna (Sowerby) (Olsson, 1961, 

p. 98, pi. 8, figs. 1, la), which first appeared in the 

fossil record during Pliocene time (Pilsbry and Olsson, 

1941, p. 51). The living species is smaller and has a 

lonsistently low ratio of height to length and undivided 

posterior ribs. A. inaequilateralis (Guppy) (Woodring, 

1925, p. 45, pi. 5, figs. 1-3; Bowden formation, Jamaica)
502 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

also is allied. It is smaller than A. dariensis dariensis, 

has a consistently low ratio of height to length, and left 

valves are not as strongly noded.

Occurrence: Lower member of Alhajuela formation 

(early Miocene), locality 84a (mold, identification doubtful). Upper member of Alhajuela formation (early 

Miocene), locality 90a (mold, identification doubtful. 

Lower, middle, and upper parts of Gatun formation 

(middle Miocene). Lower part, localities 134 (immature, identification doubtful), 136 (immature, identification doubtful), 136a, 137 (immature, identification 

doubtful), 137a, 138,138a, 138b, 138c, 138d, 138f, 138g. 

Middle part, eastern area, localities 139 (molds, identification doubtful), 139b, 139c, 139e, 139f, 140, 142, 146, 

147, 14Yb, 147c, 14Yd, 14Ye, 14Yf, 14Yg, 147h, 150a, 151, 

153,153a, 155,155a, 155b, 155c, 15Y, 158,159,159d; western area, localities 160d, 161,161a, 161b, 169. Upper part, 

eastern area, localities 171,175,176a, I77c, 178; western 

area, localities 182, 182a, 183. Deposits of middle Miocene age, Darien area, Panama (USGS 8429, 8430, 

8433, 8477). Gurabo formation (middle Miocene), Dominican Eepublic. El Veral formation (middle or late 

Miocene), Venezuela. Tubara formation (middle Miocene), northeastern Colombia. Deposits of middle 

Miocene age, southwestern Colombia. Cardalitos formation (middleMiocene), Peru. Limon formation (late 

Miocene), Bocas del Toro area, Panama.

Subgroup of large species 

Anadara (Rasia) cf. A. medioamericana (Olsson)

Moderately large, elongate, inequilateral, umbonal 

area wide. Median ribs divided at early stage by groove 

somewhat narrower than branches; posterior ribs, except those near dorsal margin, divided by narrow 

groove; anterior ribs not preserved. Median ribs faintly 

noded.

Length (incomplete) 41.5 mm (estimated restored 

length 48 mm), height 28 mm, diameter 16 mm.

Five left valves and a right of a moderately large, 

elongate species from the La Boca formation are in 

poor condition. It can be seen, however, that the median 

ribs are divided, even at a height of 10 mm.

In general features this anadarine resembles the middle Miocene Costa Bican A. medioamericana (Olsson, 

1922, p. 188, pi. 23, figs. 4-6). The median ribs of that 

species are divided at a later stage by a narrower groove.

Occurrence: La Boca formation (early Miocene), 

localities 99d, 99g.

Anadara (Rasia) honensis adiaphora Woodring, n. subsp.

Plate 82, figures 3, 6-8

Moderately large, elongate (height 67 to 69 percent 

of length), inequilateral (umbo at about anterior third 

of length), strongly inflated. Left valve slightly larger

than right. Umbo of smallest specimen slightly sulcate. 

Sculptured with 29 to 33 ribs (generally 30 or 31), 

narrower than space between them, except at anterior 

and posterior ends. Ribs undivided, except a few anterior ribs of largest left valves divided near ventral 

margin. At early stage ribs of left valve moderately 

noded, at later stages less strongly noded; at early stage 

ribs of right valve weakly noded, later faintly noded or 

almost smooth. Concentric threads of irregular strength 

and spacing. Cardinal area of moderate width; three 

of four paired ligament grooves and one or two additional posterior limbs.

Length 52.5 mm, height 35.2 mm, diameter 20.7 mm 

(type). Length 46.7 mm, height 32.2 mm, diameter 17.6 

mm (larger figured left valve).

Type :USNM 646779.

Type locality: 208 (USGS 8437, Caribbean coast at 

mouth of Eio Indies [Indio], Panama), Chagres sandstone.

Sixteen specimens, four of which are articulated, 

from the Chagres sandstone are classified as a subspecies 

of Anadara honensis (Olsson, 1922, p. 187, pi. 22, figs. 

8, 9; middle Miocene, Costa Eica). A. honensis adiaphora is larger than the nominate subspecies, less elongate, and is sculptured with more ribs (29 to 33 as 

compared with 26 or 27). In the type region southern 

Limon Province the maximum length of the nominate 

subspecies is 39 mm. A larger somewhat worn valve 

(length 45.5 mm) was collected farther north in Limon 

Province, probably on Eio Blanco (USGS 8343). A 

valve from Bowden, Jamaica, which was overlooked or 

unavailable when the Bowden pelecypods were described (Woodring, 1925) has a length of 49.9 mm.

A. margaretae (Maury, 1917, p. 169, pi. 28, fig. 1; 

middle Miocene, Dominican Kepublic) is much larger 

than the subspecies of A. honensis (length 80 mm). The 

anterior and median ribs of the left valve are strongly 

noded and the space between posterior ribs bears strong 

concentric lamella.

Occurrence: Chagres sandstone (late Miocene), locality 208.

Anadara (Rasia) actinophora actinophora (Ball) 

Plate 76, figures 4, 7, 9, 11

Scapharca (Scapharca) actinophora Ball, Wagner Free Inst.

Sci. Trans., v. 3, pt. 4, p. 647, pi. 33, fig. 26, 1898 (Miocene,

Canal Zone). 

Area actinophora (Ball), Olsson, Bull. Am. Paleontology, v. 9,

no. 39, p. 185 (assigned to subgenus SoapJiarca), pi. 23, figs.

7, 8, pi. 25, fig. 3, 1922 (Miocene, Canal Zone, Panama,

Costa Rica). 

Area (Scapharca) actinophora (Ball), Hodson, Hodson, and

Harris, Bull. Am. Paleontology, v. 13, no. 49, p. 12, 1927

(Miocene, Venezuela). Anderson, California Acad. Sci.

Proc., 4th sen, v. 18, no. 4, p. 147, 1929 (Miocene, Colombia).
GASTROPODS, SCAPHOPODS, PELECYPODS: NTJCTJLIDAE TO MALLEIDAE 503

fAnadara (Anadara) istmica Perrilliat Montoya, Mexico Univ. 

Nac., Inst. Geologla, Paleontologia Mexicana, no. 8, p. 12, 

pi. 1, figs. 3-5,1960 (Miocene, Mexico).

Moderately large, elongate (height 53 to 71 percent 

of length, 62 to 71 for mature shells), inequilateral 

(umbo at about anterior third of length), strongly inflated, ventral margin strongly arcuate, except on some 

immature shells. Left valve slightly larger than right. 

Umbo distinctly sulcate. Sculptured with 33 to 41 ribs 

(generally 40 or 41). On right valve ribs narrower than 

space between them except at anterior and posterior 

ends; on left valve almost as wide, or fully so. Eibs undivided, except a few anterior ribs on largest specimen 

(loc. 175), and practically all ribs on a right valve (loc. 

177e). Ribs of left valve strongly and closely noded except a few near posterior dorsal margin; those of right 

valve less strongly, or weakly, noded. Concentric 

threads, for most part regularly spaced, conspicuous in 

space between ribs, alined with nodes. Cardinal area 

of moderate width; two or three paired ligament 

grooves and one to three additional posterior limbs.

Length 46 mm, height 29 mm, diameter 13.8 mm 

(type). Length 48.8 mm, height 32.3 mm, diameter 

(both valves) 27 mm (larger figured specimen). Length 

(incomplete) 54.2 mm (estimated restored length 60 

mm), height 42.7 mm, diameter (both valves) 34 mm 

(largest specimen).

Type :USNM 135597.

Type locality (see explanation of Dall's plate) : 

Panama Railroad at Monkey Hill [Mount Hope], 

Canal Zone, upper part of Gatun formation.

Anadara actinophora actinophora is rare in the middle part of the Gatun formation (1 valve) and common 

in the upper part in the eastern area (34 specimens, 13 

of which are articulated). The proportion of articulated 

shells is noteworthy: 38 percent of those from the upper 

part and half of the 14 from locality 175. The size range 

in the upper part is 2.5 to an estimated 60 mm. Two immature valves from locality 175 (length 32 mm) are 

more elongate and have a less arcuate ventral margin 

than others of the same size collected at other localities. 

A right valve, the only specimen from locality 177e, is 

unique in having practically all the ribs divided. The 

sample shows a marked range of variation in the ratio 

of height to length, less so for mature specimens.

This anadarine is a large representative of a group 

characterized by a strongly arcuate ventral margin, and 

its left valve is strongly noded. The left valve of A. 

istmica (length 41) is unknown. The right valve, however, is indistinguishable from Canal Zone valves of the 

same size. The anterior and posterior ribs, and median 

ribs near the ventral margin, are divided on the type, 

but not on a USNM valve (USGS 10346). A. marksi

(Olsson, 1964, p. 27, pi. 2, fig. 8, pi. 3, figs. 2, 2a, length 

46 mm; middle Miocene, Ecuador) has weakly noded 

ribs on the left valve. It is considered to be a subspecies 

of A. actinophora. Gardner realized that her A. strebla 

(Gardner, 1926-47, p. 33, pi. 8, figs. 1, 2, 1926, length 

45.5 mm; Shoal River formation, Florida) is related to 

A. actinophora. Its posterior end is more pointed and 

the ribs of the left valve are weakly noded.

Occurrence: Middle and upper parts of the Gatun 

formation (middle Miocene). Middle part, eastern area, 

locality 155b. Upper part, eastern area, localities 163, 

172, 173, 174, 175, I76a, 177, 177b, 177d, I77e, 178. Deposits of middle Miocene age, Costa Rica, Venezuela. 

Tubara formation (middle Miocene), Colombia. Limon 

formation (late Miocene) Bocas del Toro area, Panama.

Anadara (Kasia) lienosa trochala Woodring, n. subsp. 

Plate 76, figures 5, 8, 10

Large, elongate (height 57 or 58 percent of length), 

inequilateral (umbo at about anterior third of length), 

strongly inflated, posterior margin rounded. Left valve 

slightly larger than right. Umbo distinctly sulcate. 

Sculptured with 40 or 41 ribs. Lower half of anterior 

ribs of left valve divided, others and all of right valve 

undivided. Ribs of right valve slightly narrower than 

those of left, except at posterior end. Ribs of left valve 

moderately noded, except at posterior end; those of 

right valve weakly noded. Concentric threads, of regular or irregular spacing, conspicuous in spaces between 

ribs. Cardinal area wide; six paired ligament grooves, 

and an additional anterior limb in middle of series and 

two additional posterior limbs at upper end of series.

Length 67.6 mm, height 38.6 mm, diameter 21.6 (type, 

right valve). Length 68.2 mm, height 39.6 mm, diameter 

21.3 mm (paratype, left valve).

Type: USNM 646763; paratype, USNM 646764.

Type locality: 175 (USGS 8410, Cuts on north [west] 

side of French Canal [East Diversion], Mount Hope, 

Canal Zone), upper part of Gatun formation.

The upper part of the Gatun formation at locality 175 

yielded a right valve and a left valve, which can be 

paired, of the largest and most elongate of the species 

of the subgenus Rasia in the faunas under consideration.

The general plan is that of Anadara lienosa lienosa 

(Say) and its living descendant A. lienosa secticostata 

(Reeve), also known as A. floridana (Conrad). The upper part of the posterior margin of both subspecies is 

truncated, whereas the entire posterior margin of A. 

lienosa trochala is rounded. To be sure, the Gatun 

sample is meager. Two left valves and a right (maximum length 70 mm) of A. lienosa trochala are in a collection from strata of middle Miocene age in the 

Tehuantepec area of Mexico (USGS 7251). Unlike the
504 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Gatun shells, the ribs, except the posterior ones, are 

divided 011 the lower third to lower half of the valves, 

depending on the size. The nominate subspecies itself 

occurs in the Agueguexquite formation of the Tehuantepec area (Perrilliat Montoya, 1960, p. 14, pi. 1, figs. 

1, 2; length 95 mm). If the Agueguexquite formation is 

of middle Miocene age, the nominate subspecies is a 

Caribbean migrant in southeastern United States, where 

it is unknown earlier than late Miocene.

A. floridana, that is, A. lienosa secticostata, is the type 

of the subgenus Sectiarca (Olsson, 1961, p. 97).

Occurrence: Upper part of Gatun formation (middle 

Miocene), eastern area, locality 175. Middle Miocene 

deposits, Tehuantepec area, Mexico.

Group of auriculate species

Anadara (Rasia) cf. A. emarginata (Sowerby)

Plate 77, figures, 1, 2

Small, elongate (height 64 percent of length), very 

inequilateral (umbo almost at anterior fourth of 

length), strongly inflated, auriculate. Ventral margin 

sloping downward toward posterior end, slightly insinuated. Umbo sulcate. Sculptured with 30 ribs. Median 

ribs narrower than space between them. Anterior ribs 

and lower part of anterior median ribs weakly divided. 

Concentric threads between ribs greatly subdued. 

Anterior ribs weakly noded, median ribs almost smooth, 

posterior ribs, as usual, smooth. Cardinal area very narrow ; posterior limb of a ligament groove only.

Length 20.9 mm, height 13.4 mm, diameter 6.3 mm 

(figured specimen).

A small, presumably immature (and therefore not 

named), left valve, from the upper part of the Gatun 

formation in the western area, is the only auriculate 

anadarine. It has no fossil or living allies in the Caribbean region, but is allied to the living eastern Pacific 

Anadara emarginata (Sowerby) (Maury, 1922, p. 23, 

pi. 2, figs. 5, 10; Olsson, 1961, p. 91, pi. 8, figs. 6, 6a). 

Although the number of ribs is the same or about the 

same, the posterior ribs of the living species are wider 

than those of the Gatun fossil and the anterior and 

median ribs are noded. A. emarginata reaches a length 

of almost 50 mm.

The slight insinuation of the ventral margin of the 

Gatun fossil indicates a gape. An exceptional paired 

right and left valve of A. emarginata (USNM 716408; 

Santa Elena, Ecuador; length 32.5 mm) has a distinct 

gape and extraordinarily narrow median ribs in line 

with the gape. Its six ligament grooves are bent, rather 

than angulated, a little behind the umbo.

The byssus of immature and mature A. auriculata 

that is, A. notabilis, a western Atlantic auriculate 

species was described by Perry (1940, p. 29, pi. 1, figs.

6a, 6b), and her figure 6a shows the mature byssus. She 

was mistaken, however, in mentioning a byssal notch.

Occurrence: Upper part of Gatun formation (middle 

Miocene), western area, locality 184. 

Group of short species

Many species show gradations between the arbitrarily 

divided groups of elongate and short species. The early 

Tertiary species of both groups in the faunas under consideration are small.

Anadara (Rasia) species

Small, short (height about 78 percent of length), 

very inequilateral (umbo a little behind anterior fourth 

of length). Sculptured with about 24 undivided ribs, 

about twice as wide as space between them, except at 

anterior and posterior ends. Cardinal area inaccessible.

Length (practically complete 14.1 mm, height (incomplete) 9 mm (estimated restored height 11 mm), 

diameter 6 mm.

This unnamed species is represented in the marine 

member of the Bohio( ?) formation by two poorly preserved right valves, the larger incomplete and the other 

very small (length 5 mm). The ribs of the larger valve 

are wide for the size of the shell.

Occurrence: Marine member of Bohio( ?) formation 

(late Eocene), locality 40d.

Anadara (Rasia) lita Woodring, n. sp. 

Plate 70, figures 1, 2, 6,13

Small, short (height 77 to 79 percent of length), inequilateral (umbo near anterior third of length), 

strongly inflated. Umbo slightly sulcate. Sculptured 

with 22 to 24 ribs. At early stage ribs about as wide as 

space between them, later a little narrower than space. 

Ribs of right valve weakly or faintly noded; a few near 

anterior end weakly divided near ventral margin on 

type. Kibs of left valve strongly noded, except those on 

posterior area. Cardinal area wide for size of shell; a 

pair of ligament grooves and an additional posterior 

limb on type.

Length (not quite complete) 18 mm, height 14.2 mm, 

diameter7.5mm (type).

Type: USNM 646695; paratype 646854.

Type locality: 42d (USGS 18837, Barro Colorado 

Island, northern part of island, stream heading west of 

Miller Trail near Miller 17, about 100 meters above 

mouth, Canal Zone), Boh'io f ormation.

The upper part of the Bohio formation on Barro 

Colorado Island yielded two right 'and four left valves 

of Anadara lita. A more elongate right valve (length 

10.1 mm, height 6.6 mm) from the same locality is 

doubtfully referred to it.

A. mississippiensis (Conrad) (Sheldon, 1916, p. 32, 

p'l. 7, figs. 12-16, as Area lesueuri (Dall); Byram marl, 

Mississippi) is more elongate; the ribs of the left valve
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALI/EIDAE 505

are strongly noded and divided, whereas those of the 

right valve are weakly or faintly noded and undivided, 

or only the anterior ribs are divided. [Area mississippiensis Conrad, 1847, is not a secondary homonym of 

Byssowrca mississippiensis Conrad, 1840. Therefore 

Ball's substitute name, Scapharca lesueuri (Dall, 1890- 

1903, p. 643,1898), is not justified ].

Anadara meroensis (Olsson) (1931, p. 39, pi. 2, figs. 

2, 3, 5, 6; Heath formation, Peru) 'also is more elongate 

and its ribs are divided, as well as narrower and more 

numerous than those of A. lita.

Occurrence: Bohio formation ('late Oligocene), 

locality 42d.

Anadara (Rasia) athroa Woodring, n. sp.

Plialte 72, figures 4, 6, 8

Of medium size, moderately to distinctly short 

(height 67 to 76 percent of length), very inequilateral 

(umbo a little behind anterior fourth of length). Sculptured with 34 to 39 (generally 37 to 39) closely spaced, 

weakly to strongly noded, undivided ribs. Cardinal area 

moderately narrow, not completely exposed.

Length 37.9 mm, height 26.5 mm, diameter 12 mm 

(type). Length 45.5 mm, height 31.8 mm, diameter 16 

mm (largestspecimen).

Type:USNM64uYl6.

Type locality 116a (USGS 20956, East bank of 

Panama Canal at Canal station 1870, near Paraiso, 

Canal Zone), La Boca formation.

The collections from the La Boca formation contain 

29 valves of this species, characterized by the large 

number of closely spaced, weakly to strongly noded ribs. 

Most of them, embedded in crumibly, pebbly sandstone, 

are fragile. The largest specimen is poorly preserved. 

Two small, incomplete valves from the transition zone 

between the Culebra and La Boca formations are 

doubtfully identified as Anadara athroa.

No close ally is recognized.

Occurrence: Cufebra formation (early Miocene), locality Ilia (identification doubtful). La Boca formation (early Miocene), localities 116,116a.

Anadara (Rasia) sechurana (Olsson)

Plate 79, figures 1-6, 8

Area (Diluvarca) sechurana Olss'on, Bull. Am. Paleontology, 

v. 19, no. 68, p. 67, pi. 4, fig. 1, 1932 (Miocene, Peru).

Of medium size, Lunarca-like in outline. Moderately 

short to very short (height 70 to 87 percent of length), 

inequilateral (umbo at about anterior third of length), 

moderately to strongly inflated. Left valve slightly 

larger than right. Umbo of smallest valves distinctly 

sulcate. Posterior margin rounded to obliquely truncated. Anterior part of ventral margin of smallest 

valves (length 1.5 to 7 mm) sloping more steeply than

at later stage. Sculptured with 31 to 35 ribs of varying 

width and spacing, generally wider than space between 

them. Ventral part of few anterior ribs on three right 

and three left valves divided by shallow groove; faint 

trace of groove on a few others; otherwise ribs undivided. Ribs of left valve generally moderately or weakly 

noded; those of right valve smooth or faintly noded. 

Cardinal area very narrow to very wide; ligament 

grooves variable: an unpaired anterior and posterior 

limb; or as many as three posterior limbs and no anterior ones; or one to four (generally one or two) paired 

grooves, bent rather than angulated, and one or two 

additional posterior limbs.

Length 35.8 mm, height 27.6 mm, diameter 10.2 mm 

(figured left valve). Length 38.4 mm, height 30.4 mm, 

diameter 10.8 mm (largestSpecimen).

Type: Paleontological Research Inst. 2175.

Type locality: Punta Picos, Tumbes Dept, Peru, 

upper part of Zorritos formation.

Three hundred and fifty specimens of Anadara sechurana from the Gatun formation, including eight that 

are articulated, are available. All except five were found 

in the lower part of the formation, 175 at locality 138c. 

The exceptions occur in the middle part, three of them 

near the base of that part.

This species is widely variable in almost every diagnostic feature: outline, inflation, width and spacing of 

ribs, and width of cardinal area and arrangement of 

ligament grooves. Relatively elongate (pi. 79, fig. 5) and 

sharply truncated (pi. 79, fig. 8) valves, however, are 

rare, and so are those that have a very wide cardinal 

area (pi. 79, fig. 4).

No closely comparable fossil or living species is recognized. A transversa (Say) (S'heldon, 1916, p. 47, pi. 11, 

figs. 4-6), which ranges from Massachusetts to Florida 

and the Gulf o'f Mexico, is less Lunarca-liks.

Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, localities 137a, 

138, 138a, 138b, 138c, 138d, 138f, 138g. Middle part, 

eastern area, localities 139g, 144, 144a. Upper part of 

Zorritos formation and Montera formation (both middle Miocene), Peru.

Anadara (Rasia) fissicosta (Spieker) 

Plate 78, figures 1-6

Area (Scapharca) fissicosta Spieker, John® Hopkins Univ., 

Studies in Geology, no. 3, p. 102, pi. 5, fig. 11, 1922 (Miocene, 

Peru).

Of medium size, almost invariably Lunarca-like in 

outline. Moderately short to very short (height 70 to 

91 percent of length, generally 78 to 84), very inequilateral (umbo at about anterior fourth of length), moderately inflated. Left valve larger than right. Umbo 

sulcate. Posterior margin rounded to obliquely subtrun-
506 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

cated. Sculptured with 32 to 45 (generally 38 to 45) 

narrow, closely spaced ribs, generally wider than space 

between them. Faint trace of median groove on few anterior ribs of two right valves, otherwise ribs undivided. 

Ribs of left valve almost invariably strongly and closely 

noded, exceptionally moderately noded on some small 

valves; those of right valve smooth or faintly noded. 

Cardinal area narrow to moderately narrow; one to 

three (generally one) paired ligament grooves, generally bent, exceptionally angulated, and an additional 

posterior limb; or no paired grooves and only a posterior 

limb.

Length: 29.5 mm, height 23.8 mm, diameter (both 

valves) 21.4 mm (figured articulated specimen). Length 

36.6 mm, height (not quite complete) 29 mm (estimated 

restored height 32 mm), diameter 15.5 mm (largest 

specimen, figured).

Type :USNM 562365.

Type locality: Quebrada Zapotal, Zorritos area, 

Tumbes Dept., Peru, lower part of Zorritos formation.

Anadara fissicosta^ like A. sechurana, is abundant in 

the lower part of the Gatun formation and rare in the 

middle part. Two of the 92 specimens, 10 of which are 

articulated, were collected from strata near the base of 

the middle part: a minute right valve and the illustrated 

relatively elongate left (pi. 78, fig. 2). These fossils 

range in length from 2 to 36.6 mm. The largest has also 

the widest cardinal area (pi. 78, figs. 1, 3). Two poorly 

preserved specimens from the upper member of the Alhajuela formation are listed as Anadara cf. A. fissicosta.

It is noteworthy that both short anadarines in the 

Gatun formation are Peruvian species. Those two species 

are allied. A. fissicosta is distinguished by its generally 

higher rib count and especially by the almost invariable 

strong noding of left-valve ribs; it also runs smaller and 

shorter. To be sure, the rib count overlaps in the two 

species. Nevertheless some 80 percent of the shells of 

A. fissicosta have a count of 38 to 45. A total of 15 left 

valves, all of moderate or small size, have a count of 32 

to 37 (seven from locality 138c, four locality 138d, 

three locality 138f, and one locality 139c). That from 

locality 139c (pi. 78, fig. 2) has the lowest ratio of 

length (70 percent). It resembles in a general way 

A. perplwa (Woodring, 1925, p. 44, pi. 4, fig. 7; Bowden 

formation, Jamaica), which is more inflated and has 

wider ribs.

In Panama A. fissicosta reaches a slightly larger 

size than in Peru. A few anterior ribs on the type, a right 

valve, are divided near the ventral margin. Two right 

valves from Panam& (Iocs. 138c and 138g) show a faint 

trace of a median groove on a few anterior ribs, but the 

difference in that feature is of no taxonomic significance. 

No Peruvian left valve is available.

Perhaps too many other names have been proposed 

for short anadarines in the Zorritos formation of 

Peru: A. zapatolensis, A. singewaldi, and A. swgewaldi 

doma (Spieker, 1922, p. 101, pi. 5, fig. 10; p. 103, pi. 5, 

figs. 12, 13; p. 106, respectively), and A. spiekeri (Olsson, 1932, p. 65, pi. 2, figs. 2, 3, 6). The anadarines that 

bear those names are smaller than A. fissicosta and like 

that species show a considerable range in outline. Their 

rib count is 31 to 36 as compared with 39 for the single 

Peruvian A. fissicosta. (The 50 count cited for A. singewaldi doma evidently is a typographic error for 30, actually 31.)

Comparable short anadarines occur in early and middle Miocene formations in Venezuela: A. zuliana and 

the synonymous A. zuliana maracaibensis (H. K. Hodson, in Hodson, Hodson, and Harris, 1927, p. 4-5, pi. 4, 

figs. 7-11, and A. cf. A. spiekeri (Jung, 1965 p. 432, pi. 

53, figs. 6,7).

Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, localities 136, 

136a, 137, 137a, 138a, 138b, 138c, 138d, 138f, 138g. Middle part, eastern area, localities 139b, 139c. Lower part 

of Zorritos formation (early Miocene), Peru.

Group of subrounded species

The group of subrounded species is not represented in 

the faunas under consideration. It is typified by Anadara pennelli (Gabb) (Pilsbry, 1922, p. 403, pi. 39, figs. 

3, 4), which is abundant in the Cercado formation of 

the Dominican Republic. That species has seven synonyms, including A. tolepia (Dall, 1890-1903, p. 649, pi. 

33, figs. 7, 8, 1898; Miocene, Dominican Republic), A. 

arthurpennelli (Maury, 1917, p. 178, pi. 29, figs. 9, 10; 

Miocene, Dominican Republic), and A. microtera 

(Woodring, 1925, p. 49, pi. 5, figs. 12, 13: Miocene, 

Jamaica).

Subgenus Tosarca Noda 

Noda, Palaeontological Soc. Japan, Trans. and Proc., no. 59, p.

104, 1965.

Type (orthotype) : Anadara (Tosarca) tosaensis Noda, Pliocene, 

Japan.

Tosarca is used for subquadrate anadarines, which 

are further characterized by a wide umbonal area.

Anadara (Tosarca) campta Woodring, n. sp.

Plate 73, figure 8

Of medium size, very short (height 81 percent of 

length), very inequilateral (umbo at about anterior 

fourth of length), umbonal area wide and inflated. Outline subquadrate, anterior margin rounded, posterior 

margin obliquely truncated. Posterior umbonal slope 

subangulated, posterior area slightly concave. Left valve 

sculptured with about 33 moderately noded ribs, slightly 

wider than space between them. Ribs divided, except on 

posterior area. Right valve unknown. Cardinal area
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 507

moderately wide; traces of three posterior limbs of ligament grooves visible.

Length (practically complete) 34.6 mm, height 28 

mm, diameter about 17 mm (type).

Type :USNM 646719.

Type locality: lOlh (USGS 23652, Panama Canal, 

west side of Las Cascades Reach, Canal stations 1608 to 

1612 plus 23 meters, near top of Canal cliff, Canal 

Zone), La Boca formation.

Though little shell material is left on two left valves 

of Anadara campta from the La Boca formation, the 

outline and ribbing, except the ribbing on part of the 

posterior area, are well shown on the larger (the type) 

and the cardinal area is exposed on the smaller.

The ribs of this species are narrower and less strongly 

noded than those of the left valve of A. santarosana 

geraetera (Gardner, 1926-47, p. 31, pi. 7, figs. 1, 2,1926; 

Chipola formation, Florida) and the median ribs are 

divided.

Occurrence: La Boca formation (early Miocene), locality lOlh.

Anadara (Tosarca) cf. A. tectumcolumbae (Maury) 

Plate 73, figure 3

Of medium size, very short (height 80 to 81 percent 

of length), inequilateral (umbo at anterior third of 

length). Outline subquadrate, anterior margin rounded, 

posterior margin obliquely truncated. Posterior umbonal slope subangulated, posterior area slightly concave. 

Sculptured with 30 or 31 ribs, slightly wider than space 

between them. Anterior ribs faintly divided, weakly 

noded at least on left valve. Cardinal area narrow, corroded.

Length 36.5 mm, height (not quite complete) 25.5 mm 

(estimated restored height 30 mm), diameter about 13 

mm (figuredspecimen).

This species occurs in the upper member of the Alhajuela formation. It is most similar to Anadara tectumcolmribae (Maury, 1925, p. 52, pi. 7, fig. 4; G. D. Harris 

in Waring, 1926, p. 109, pi. 20, figs. 1, 2, as a variety; 

Savaneta glauconitic sandstone member of Springvale 

formation, Trinidad), which is larger (length 40 to 

60 mm), shorter (height 85 to 88 percent of length), 

and has more ribs (35 to 39).

The 11 specimens are molds, or almost entirely molds. 

That illustrated is a latex cast.

Occurrence: Upper member of Alhajuela formation 

(early Miocene), localities 85, 85a, 89, 90a.

Anadara (Tosarca) veatchi veatchi (Olsson) 

Plate 78, figures 7-11

Area Veatchi Olsson, Bull. Am. Paleontology, v. 9, no. 39, p. j.89 

(assigned to subgenus Scapharca), pi. 23, figs. 1-3, 1922 

(Miocene, Panama).

Area (Scapharca?) veatchi Olsson, Anderson, California Acad.

Sci. Proc. 4th ser., v. 18, no. 4, p. 150, 1929 (Miocene,

Colombia). 

Area (Scapharca) veatchi Olsson, Barrios, Colombia Servicio

Geol. Nac., Bol. Geol., v. 6 nos. 1-3 (Informe 1082), p. 230,

pi. 1, figs. 4, 5, 1960 (Miocene, Colombia).

Large, Oardium-like, very short (height almost equal 

to length), inequilateral (umbo at about anterior third 

of length), umbonal area wide and inflated. Outline subquadrate, anterior margin broadly rounded, posterior 

margin slightly rounded. Anterior part of ventral margin of smallest shells (length 10 to 12.7 mm) sloping 

more steeply than at later stage. Left valve slightly 

larger than right. Umbo sulcate. Sculptured with 40 

to 48 (generally 42 to 45) narrow, closely spaced ribs; 

as usual, anterior and posterior ribs wider and more 

widely spaced than elsewhere. Ribs of right valve 

faintly noded or smooth, except for stronger noding on 

anterior ribs; anterior and posterior ribs divided by one 

to three grooves (generally one). Ribs of left valve 

strongly and closely noded, except for weaker noding 

on anterior and posterior ribs; anterior and posterior 

ribs, and ventral part of median ribs, divided by one 

to three grooves. Concentric threads between ribs, alined 

with nodes, generally conspicuous. Cardinal area narrow ; one to two pairs of ligament grooves and an additional posterior limb.

Length 54.5 mm, height 49.2 mm, diameter 20.5 mm 

(largest figured specimen). Length (incomplete) 55.2 

mm (estimated restored length 63 mm), height 56.3 mm, 

diameter (both valves, reduced by crushing) 34 mm 

(largest specimen).

Type: Paleontological Research Inst. 21201.

Type locality: Water Cay, Bocas del Toro area, Panama Limon formation.

This handsome species was the first of its lineage to 

be named. Though it occurs in the middle Miocene of 

Panama, Colombia, and Venezuela, and in the late Miocene of Panama, it left no descendants in the western 

Atlantic Ocean. The lineage was continued in the Pliocene of Ecuador by Anadara hopMnsi (Pilsbry and Olsson, 1941, p. 51, pi. 11, figs. 1,2), which is larger than A. 

veatchi (length 93 mm), less distinctly noded, and its 

ribs are divided by more numerous grooves, and servives in the eastern Pacific Ocean: A. hyphalopilema 

(Campbell, 1962; off Guaymas, Mexico). The living 

species is larger than A. veatchi (length and height 60 

mm) and, like A. hopkinsi, its ribs are divided by more 

numerous grooves and it is less distinctly noded. It has 

a remarkable feltlike periostracum.

A. veatchi veatchi occurs throughout the Gatun formation but is nowhere abundant. Eight of the 23 specimens are immature and two are represented only by 

fragments.
508 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

The ribs of the only available left valve from Colombia are moderately noded. A Venezuelan subspecies A. veatchi matarucana (H. K. Hodson, in Hodson, Hodson, and Harris, 1927, p. 10, pi. 3, figs. 4, 5; 

Jung, 1965, p. 429, pi. 52, figs. 5, 6, 9; Caujarao and 

Cantaure formations) has an ill-defined, rounded 

posterior umbonal slope.

Occurrence: Lower, middle, and upper parts of Gatun 

formation (middle Miocene). Lower part, locality 138a. 

Middle parts, eastern area, localities 147b, 147g, 155, 

157. Upper part, eastern area, localities 174, 175, I76a, 

178; western area, localities 182a, 183, 184, 185. Tubara 

formation (middle Miocene), Colombia. Limon formation (late Miocene), Bocas del Toro area, Panama.

Anadara (Tosarca) species

Two immature left valves from the middle part of 

the Gatun formation have a length of 3 and 9 mm. The 

umbo of the smaller is faintly sulcate and of the larger 

not sulcate. The anterior part of the ventral margin 

slopes less steeply than that of the smallest valves of 

Anadara veatcM veatchi. They are sculptured with 32 

or 36 closely spaced, narrow ribs, which are not quite 

as strongly noded as those of left valves of A. veatchi 

veatchi.

Perhaps this anadarine is an unnamed species that 

occurs in middle Miocene deposits in southeastern Costa 

Rica (USGS 5882c) and northeastern Colombia 

(USGS 11323,11334, and other localities). It reaches a 

length of 45 mm and has 30 to 32 ribs. At a mature 

stage the ribs are more widely spaced than those of 

A, veatchi veatchi.

Occurrence: Middle part of Gatun formation (middle 

Miocene), eastern area, localities 144c, 155c.

Subgenus Grandiarca Olsson 

Olsson, Mollusks of the tropical eastern Pacific; PanamicPacific Pelecypoda, p. 93, Paleontological Research Inst.,

1961. 

Type (orthotype) : Area grandis Broderip and Sowerby, living,

eastern Pacific Ocean.

The sole surviving species, the type species, and also 

the Tertiary species now assigned to Grandiarca have 

been referred to the genus Senilia (Gray, 1842, p. 81, 

genus without species; type (orthotype and tautotype, 

Gray, 1847, p. 198) : Area senilis Linne, living, west 

coast of Africa) by several authors (Morch, 1861, p. 

205; Lamy, 1907, p. 262; Woodring, 1928, p. 58, 71, 

79-80; Olsson, 1932, p. 71-76). Eeinhart's (1935, p. 41) 

objection to that arrangement was justified, but his 

assignment of them to his Larkinia (Eeinhart, 1935, 

p. 41; type (orthotype and tautotype) : Anadara 

larkinii (Nelson) [Area larkinii Nelson]; Miocene, 

Peru) was hardly an improvement. Anadara larkinii 

(Olsson, 1932, p. 75, pi. 2, figs. 1, 4, 5) is a remarkable

species; it combines a narrow umbo, subtrigonal outline, 

angular posterior umbonal slope, flattened, barely concave posterior area, coarsely noded ribs, and very wide 

cardinal area; in addition it is equivalve. The only resemblance to Grandiarca lies in the coarsely noded undivided ribs, very wide cardinal area, and equal size of 

the valves. A. larkinii has no known predecessors. It survived until early Pliocene time in Ecuador (Pilsbry 

and Olsson, 1941, p. 53). A closely related new species 

occurs in the early Pliocene El Salto formation of 

Nicaragua (USGS'3094).

Anadara grandis lives in mud or muddy sand bordering mangrove swamps, as does Senilia senilis (Yonge, 

1955, p. 202). Great piles of the big thick shells of 

A. grandis may be seen along the brackish-water lower 

course of Rio Tumbes in northern Peru, where, as elsewhere, it is used for food. Rio Tumbes is the southern 

limit of A. grandis and of mangrove swamps on the 

Pacific coast of South America (Olsson, 1961, p. 94).

The species of Grandiarca in the Tertiary Caribbean 

province are found in brackish-water, mixed brackishwater and marine, and marine assemblages; tftiait is, they 

evidently tolerated a considerable range of salinity. 

Though they occur in the western Atlantic part of the 

province in Jamaica, Haiti, the Dominican Republic, 

Anguila, Tobago, Trinidad, Venezuela, Colombia, 

Panama, and Costa Rica, none survives in the western 

Atlantic Ocean, and only the type species survives in 

the eastern Pacific Ocean. The age range in the Caribbean part of the province is early Miocene to early Pliocene; in the Pacific part early Miocene to the present 

time.

Two groups of Grandiarca are represented in the Tertiary Caribbean province: a group of small or relatively 

small species, typified by Anadara chiriquiensis, and a 

group of large species typified by A. grandis.

Group of small species

Anadara (Grandiarca) chiriquiensis chiriquiensis (Gabb) 

Plate 72, figures 17, 18

Area, chiriquiensis Gabb, Acad. Nat. Sci. Philadelphia Proc., 

1860, p. 567, 1861 (Miocene, Panama). Pilsbry. Acad. Nat. 

Sci. Philadelphia Proc., v. 73, p. 405, pi. 40, figs. 2-6, pi. 41, 

figs. 1-3, 1922 (Miocene, Panama, Dominican Republic).

Scapharca (Scapharca) chiriquiensis (Gabb), Ball, Wagner 

Free Inst. Sci. Trans., v. 3, pt. 4, 642, 1898 (Miocene, 

Panama, Dominican Republic). Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 59, pi. 2, fig. 2, 1925 (Miocene, 

Dominican Republic).

Scapharoa chiriquiensis (Gabb), Maury, Bull. Am. Paleontology, 

v. 5, no. 29, p. 174, pi. 28, fig. 2, 1917 (Miocene, Dominican 

Republic). Woodring, in Woodring, Brown, and Burbank, 

Geology of the Republic of Haiti, Republic Haiti Geol. 

Survey, p. 191, pi. 16, figs. 6-8, 1924 (Miocene, Haiti).

Not Area (Scapharca) chiriquiensis Gabb, Tucker and Wilson, 

Bull. Am. Paleontology, v. 18, no. 65, p. 4, pi. 1, figs. 1, 5,1932 

(Miocene, Florida), = Area (Anadara) sellardsi Mansfield.
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 509

Area welsteri Pilsbry, Acad. Nat. Sci. Philadelphia Proe., v. 62, 

p. 488, 1910 (Miocene, Haiti). Not Area websteri Forbes, 

Tertiary fluvio-marine formation of the Isle of Wight: Geol. 

Survey Great Britain and Mus. Practical Geol. Mem., p. 62, 

68, explanation of plate, pi. 3, figs. 8, 8a, 1856.

Area, chiriquiensis welsteri Pilsbry, Pilsbry, Acad. Nat. Sci. 

Philadelphia Proc., v. 73, p. 406, pi. 41, fig. 4, 1922 (Miocene, 

Haiti).

Scapharca chiriquiensis websteri (Pilsbry), Woodring, in Woodring, Brown, and Burbank, Geology of the Republic of Haiti, 

Republic Haiti Geol. Survey, p. 201, pi. 16, flgs. 9-11, 1924 

(Miocene, Haiti).

Scapharca chiriquiensis bolivari Weisbord, Bull. Am. Paleontology, v. 14, no. 54, p. 8, pi. 1, figs. 4-9, 1928 (Miocene, 

Colombia).

Area (Senilia) chiriquiensis bolivari (Weisbord), Barrios, Colombia Servicio Geol. Nac. Bol. Geol., v. 6, nos. 1-3 (Informe 

1082), p. 229, pi. 1, fig. 2, 1960 (Miocene, Colombia).

Anadara sp. aff. A. chiriquiensis bolivari (Weisbord), Hedberg, 

Geol. Soc. Am. Bull., v. 48, p. 2,011, pi. 8, figs. 1, la, 2, 1937 

(Miocene, Venezuela).

fArca septifera Grzybowski, Neues Jahrb., Beilage-Band, v. 12, 

p. 633, pi. 18, figs. 2, 2a, 1899 (Miocene, Peru).

fArca (Anadara) septifera Grzybowski, Spieker, Johns Hopkins 

Univ., Studies in Geology, no. 3, p. 117, pi. 6, figs. 5, 6, 1922 

(Miocene, Peru).

fArca (Senilia) chiriquiensis septifera Grzybowski, Olsson, Bull. 

Am. Paleontology, v. 19, no. 68, p. 73, pi. 1, fig. 5, 1932 

(Miocene, Peru).

Area obesiformis Grzybowski, Neues Jahrb., Beilage-Band, v. 

12, p. 633, pi. 18, figs. 3, 3a, 1899 (Miocene, Peru).

Area (Soapharca) olesiformis Grzybowski, Spieker, Johns Hopkins Univ., Studies in Geology, no. 3, p. 115, pi. 6, figs. 1, 2, 

1922 (Miocene, Peru).

Area (Senilia) chiriquiensis obesiformis Grzybowski, Olsson, 

Bull. Am. Paleontology, v. 19, no. 68, p. 74, 1932 (Miocene, 

Peru).

Area (Soapharca) imporoata Spieker, Johns Hopkins Univ., 

Studies in Geology, no. 3, p. 113, pi. 5, figs. 19, 20, 1922 (Miocene, Peru).

Area (Scapharca) crescens Spieker, Johns Hopkins Univ., Studies in Geology, no. 3, p. 116, pi. 6, fig. 34, 1922 (Miocene, 

Peru).

Area (Anadara) nelsoni Spieker, Johns Hopkins Univ., Studies 

in Geology, no. 3, p. 119, pi. 6, figs. 7, 8, 1922 (Miocene, 

Peru).

Area (Anadara) toroensis Spieker, Johns Hopkins Univ., Studies 

in Geology, no. 3, p. 121, pi. 6, figs. 9, 10, pi. 7, fig. 1, 1922 

(Miocene, Peru).

Area (Senilia) chiriquiensis toroensis Spieker, Olsson, Bull. Am. 

Paleontology, v. 19, no. 68, p. 11, pi. 1, figs. 3, 4, 1932 (Miocene, Peru).

Area (Anadara) toroensis crassa Spieker, Johns Hopkins Univ., 

Studies in Geology, no. 3, p. 124, pi. 7, fig. 2, 1922 (Miocene, 

Peru).

Area (Anadara) toroensis prolata Spieker, Johns Hopkins Univ., 

Studies in Geology, no. 3, p. 125, pi. 7, fig. 3, 1922 (Miocene, 

Peru).

Of medium size, very short (height 86 to 96 percent 

of length), inequilateral (umbo at anterior third of 

length), strongly inflated. Posterior margin obliquely 

subtruncated, extended at ventral end. Sculptured with 

31 or 32 ribs, wider than space between them. Anterior

and median ribs of left valve strongly to moderately 

noded. Eibs of available right valves corroded. Cardinal 

area very wide for size of shell; at least three paired 

ligament grooves.

Length 42.2 mm, height 37.6 mm, diameter 23 mm 

(figured corroded specimen).

Type: The specimen illustrated by Pilsbry (1922, 

pi. 40, fig. 2; see explanation of his plate), Acad. Nat. 

Sci. Philadelphia 2724.

Type locality: Bio Changuinola district, Bocas del 

Toro area, Panama, deposits of middle Miocene age.

Anadara chiriquiensis chiriquiensis is identified in 

collections from two localities in the Culebra formation: 

a left valve from locality 103 (pi. 72, fig. 18), where 

it is associated with Crassostrea, and 25 corroded valves 

from locality 110, one of which is illustrated (pi. 72. fig. 

17). Locality 110 is in the transition zone between the 

Culebra and Cucaracha formations. The fossils in that 

zone represent a mixed brackish-water and marine association.

This greatly overnamed anadarine is variable in outline. Eight names have been proposed for specimens 

from the Zorritos formation of Peru. All occur in the 

upper part of the formation and one in both upper 

and lower parts. Should population studies be undertaken, some of the names may be found useful.

The type and paratype lots, now consisting of eight 

specimens, were collected by John Evans (18,61, p. 48) 

during his exploration for coal (lignite) in extreme 

northwestern Panama. He found fossils ("cardium, cerithium, area, obeliscus, pinna, solen, natica, &c.") in 

strata ovelying coal-bearing rocks on two tributaries 

of Bio Changuinola. Gabb gave to Dall three articulated 

specimens from the original lot (TJSNM 13229). The 

paratype illustrated by Pilsbry (1922, plate 40, figure 3) 

(length 73 mm) is the largest so far recorded. Orcutt 

collected a fine large left valve in the Central Plain of 

Haiti (USNM 496471, length 60 mm). The recorded rib 

count ranges from 27 to 32.

Area websteri was based on a relatively elongate 

Haitian form. The name is a junior homonym.

Area anguillana (Cooke, 1919, p. 127, pi. 5, figs. lOa, 

lOb; Anguilla formation, Anguilla) is tentatively classified as a small subspecies of Anadara chiriquiensis 

(length 31.3 mm). The type, a right valve, is the only 

specimen. It has the outline of the typical form of the 

nominate subspecies, but the ribs are more closely spaced 

and more finely noded than those of the typical form. 

A larger sample is desirable.

Anadara garitensis (Olsson, 1932, p. 75, pi. 1, fig. I), 

which occurs in the late Miocene Tumbes formation of 

Peru, is the largest and highest of the group of small 

species of Grandiarca (length 78 mm, height 80 mm). 

It is sculptured with about 24 ribs.
510 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Occurrence: Culebra formation (early Miocene) localities 103,110. Deposits of middle Miocene age, Bocas 

del Toro area, Panama. Lower and upper parts of Zorritos formation (early and middle Miocene, respectively), Peru. Thomonde, Maissade, and Las Cahobas 

formations (early and middle(?) Miocene), Haiti. Middle(?) Miocene part of Santa Ines group, Venezuela. 

Deposits of middle or late Miocene age, Dominican 

Republic. Deposits of middle Miocene age, Columbia.

Anadara (Grandiarca) balboai (Sheldon) 

Plate 72, figures 10, 11, 15

Area dalli Brown and Pilsbry, Acad. Nat. Sci. Philadelphia Proc.,

v. 64, p. 510, pi. 24, fig. 4, 1913 (Miocene, Canal Zone). Not

Area (Macrodon) dalli E. A. Smith, 1885. 

Area 'balboai Sheldon, Palaeontographica Americana, v. 1, no. 1,

p. 69, 1916. Substitute name for Area dalli Brown and

Pilsbry. 

ScapJiarca (Scapharca) balboae (Sheldon), Maury, Bull. Am.

Paleontology, v. 10, no. 42, p. 65, 1925 (Miocene, Canal

Zone). 

Area invalida Hanna, California Acad. Sci. Proc., 4th ser.,

v. 13, no. 10, p. 157, 1924. Substitute name for Area dalli

Brown and Pilsbry.

Of medium size, moderately short to very short 

(height 73 to 94 percent of length, generally 83 to 89), 

inequilateral (umbo at anterior third to almost fourth 

of length), strongly inflated, equivalve. Posterior margin slightly rounded to obliquely subtruncated, extended or broadly rounded at ventral end. Sculptured with 

27 to 37 (generally 31 to 33) ribs, slightly to decisively 

wider than space between them. Anterior ribs of right 

valve moderately to strongly noded, others weakly noded 

to smooth. Ribs of left valve moderately to strongly 

noded. Cardinal area moderately narrow to moderately 

wide; two paired ligament grooves and an additional 

posterior limb.

Length 38 mm, height 29.5, diameter 19 mm (larger 

figured specimen). Length 38.2 mm, height 28 mm, 

diameter about 15 mm (largest specimen).

Type: Acad. Nat. Sci. Philadelphia 3831, now lost or 

misplaced.

Type locality: Bottom of Culebra Cut, near Tower 

N, Canal Zone, lignitic clay below "Pecten bed;" that is, 

Las Cascadas Reach, Gaillard Cut, near Canal station 

1600, La Boca formation.

Anadara balboai occurs in the Culebra and La Boca 

formations (16 and 70 specimens, respectively, three 

articulated). It is a variable species variable in outline and spacing of ribs. The greatest variability is 

shown by well-preserved immature shells from the La 

Boca at locality 116a. The size range at that locality is 

7.7 to 33.3 mm. The specimens from locality 99b are virtual topotypes so far as locality is concerned, but are 

from a higher level in the La Boca than the type. They 

are not well preserved. The largest specimens were 

found in the Culebra formation.

In general features A. ~baTboai is similar to A. chiriquiensis. It is not only smaller than that species, it 

also has more slender rib nodes, and its cardinal area is 

narrower. In fact, for a species of Grandiarca the cardinal area is unexpectedly narrow. Perhaps A. balboai 

represents a branch of the A. chiriquiensis lineage 

adapted to an open sea habitat, although at six of the 

nine localities where it is unequivocally identified, it was 

collected in association with Potamides and Crassostrea, 

both of which prefer brackish water. At those localities, however, also normal marine genera were collected.

This species has not been found elsewhere.

Occurrence: Culebra formation (early Miocene), localities 102 (identification doubtful), 106, 107, 108c, 

109, HOa (identification doubtful). La Boca formation (early Miocene), localities 99b, lOOa (identification doubtful), 101, lOla, 115b, 116a.

Anadara (Grandiarca) dolaticosta (Pilsbry and Johnson)

Plate 80, figures 6-9, 12

Area dolaticosta Pilsbry and Johnson, Acad. Nat. Sci. Philadelphia Proc., v. 69, p. 188, 1917 (Miocene, Panama). Pilsbry, 

Acad. Nat. Sci. Philadelphia Proc., v. 73, p. 406, pi. 41, 

figs. 5, 6,1922 (Miocene, Panama).

Moderately large (but not as large as largest Anadara chiriquiensis), (7ardium-IikQ, length and height 

almost equal, almost equilateral, umbonal area very wide 

and very inflated. Margins defective. Sculptured with 

26 wide ribs, wider than space between them. Ribs of 

right valve, except a few near dorsal margins, coarsely 

and strongly noded. Cardinal area wide; three paired 

ligament grooves and an additional posterior limb.

Length (incomplete) 48 mm (estimated restored 

length 55 mm), height (incomplete) 49.2 mm (estimated restored height 57 mm), diameter 30 mm (figured 

specimen from locality 170).

Type: Acad. Nat. Sci. Philadelphia 2738.

Type locality: Same as preceding species.

This remarkable species is represented by a battered, 

corroded right valve, which clearly was transported and 

buried some distance from its habitat, or was reworked 

from older strata. It was found in the middle part of the 

Gatun formation in the western area.

The type of Anadara dolaticosta and another specimen were collected by Evans at the type locality of A. 

chiriquiensis. In 1917 I collected, from middle Miocene 

strata, 13 specimens, six articulated, at three localities 

(USGS 8009, 8010, 8011) on Quebrada Schawb (prob-
GASTROPODS, SCAPHOPODS, PELBCYPODS: NUCULIDAE TO MALLEIDAE 511

ably an erroneous transliteration of an Indian name), 

the first upstream southeastward-flowing tributary of 

Rio Yorkin; that is, on the Costa Eican side of the 

Costa Rica-Panama boundary, about 40 km northwest 

of the type region. The length of the Costa Eican fossils 

ranges from 12.4 to 57 mm. One of medium size is illustrated (pi. 80, figures 7, 8, 12) to show the outline and 

the uncorroded ribs. The ribs are narrower than those 

of the Gatun fossil, but that feature is variable in the 

Costa Rican sample.

A closely related species, or a subspecies of A. dolaticosta, is found in middle Miocene strata on the Pacific 

side of Panama in both Darien and Chiriqui Provinces 

(USGS 8432, and 6513, 6514, 7958, respectively). The 

ribs of the Pacific form are lower and not as coarsely 

noded. A. zorritosensis (Woods, 1922, p. 112, pi. 18, figs. 

5a-5c; Olsson, 1932, p. 74; Zorritos formation, Peni) 

also is closely related. According to the illustration, the 

wide ribs are separated by very narrow spaces. It was 

not represented in the Zorritos collections studied by 

Spieker (1922) and Olsson (1932).

A. dolaticosta as noted by Pilsbry and Johnson, a 

very distinct species left no descendants.

Occurrence: Middle part of Gatun formation (middle Miocene), western area, locality 170. Middle Miocene deposits, southeastern Costa Rica, northwestern 

Panama.

Group of large species

The group of large species of G-randiarca embraces 

the living Anadara grandis grandis and its fossil allies, 

many of which are some 100 mm long. A grandis grandis 

itself is the largest. A massive valve (USNM 3622) has 

a length of 145 mm and weighs 1.2 kg.

The fossil allies are widespread in the Miocene of the 

present Caribbean region and there range into the Pliocene. They are subdivided as brackish-water and marine 

species, or subspecies. Evidence is available that A. 

grandis patricia lived in a brackish-water habitat in 

the northern part of the Dominican Republic (Maury, 

1917a, p. 25; 1922, p. 32), in Trinidad (Rutsch, 1942, p. 

221), and in southeastern Costa Rica, where it occurs in 

strata interbedded with lignite. Though the habitat of 

the specimens from the Gatun formation is unknown, 

they did not live with the marine fossils collected at 

the same locality and are arbitrarily classified as 

brackish-water. On the contrary, A. grandis colombiensis is associated with marine fossils in Colombia, as 

noted by Anderson (1929, p. 149), Venezuela, and the 

southwestern part of the Dominican Republic. A. 

waringi also is associated with marine fossils.

A survey of 270 fossil and living USNM specimens is 

tabulated on page 512. A short, high form of A. grandis 

patricia is recorded from Tobago (Trechmann, 1934, p. 

488, pi. 25, figs. 12,13), but none is available. All of those 

tabulated, except the articulated specimen from the 

southwestern part of the Dominican Republic listed as 

Anadara n. sp., are more or less similar in outline, and 

all are similar in number of ribs and noding of anterior 

ribs. A. grandis colombiensis, as identified, is the most 

variable of the fossil forms, even at a single locality 

in Colombia. A. ivaringi, an endemic Trinidad species, 

is the least variable. It is the smallest, and its median 

ribs generally are noded. Only one specimen is in collections from the San Jose calcareous silt member of 

the Manzanilla formation; the others are from the overlying Montserrat glauconitic sandstone member. (For 

citations for the species and subspecies see footnotes at 

end of table).

Anderson (1929, p. 148) commented on the hinge of 

his Area usiacurii (that is, Anadara grandis colombiensis) as compared with that of Anadara grandis grandis. Though he emphasized the branching of the teeth 

near the ends of the hinge of his fossils, that feature 

is trivial or nonexistent. His illustrations (Area usiacurii, pi. 19, fig. 6, pi. 21, fig. 4; Area grandis, pi. 18, 

fig. 1) show that the hinge of the fossils is higher. 

The difference, however, is not consistent. As listed 

in the table, the hinge of 67 percent of the Colombian 

fossils that show the hinge, including all of medium 

size, is higher than that of Anadara grandis grandis, 

but 14 percent, all large valves, resemble the living 

form in that feature. There is also no consistency in 

marine forms as compared with brackish-water forms. 

Nevertheless in the brackish-water group a hinge as 

high as that of many valves of A. grandis colombiensis 

was observed only on some valves of A. grandis patricia 

from Trinidad. The tendency toward a high hinge 

and the marine habitat are considered to be justification 

for the recognition of A. grandis colombiensis.

As shown in the table, the age range of the Caribbean 

fossils is early (?) Miocene to early Pliocene. At three 

of the four localities in the southwestern, part of the 

Dominican Republic (USGS 8572, 8590, 8760) A. grandis colotnbiensis and Anadara n, sp. are associated with 

Orthaulax aguadillensis. Elsewhere that species occurs 

in formations dated as early Miocene, although, of 

course, it may have survived later in the Dominican 

Republic. Marine fossils recently found in the Caparo 

clay member of the Talparo formation in central Trinidad are of Pliocene age (June, 1969a, p. 85), early 

Pliocene.
512 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Tertiary and living large species of Anadara, subgenus Grandiarca

^ 

w

I

MM

.§

Marine sp

Species and 

subspecies

Anadara 

grandis 

grandis 

(Broderip 

and Sow- erby)!, 2

Anadara 

grandis 

patricia 

(Sowerby) 7

Anadara 

grandis 

colombiensis (Weisbord) ion

Anadara 

waringi (Maury) 13 "

Anadara 

grandis 

colombiensis 

Weisbord)

Anadara n.sp.

Age

Pliocene to 

Holocene

Early 

Pliocene

Late(?) 

Miocene

Middle

Middle to 

late 

Miocene

Middle 

Miocene

Early(?)

Number of 

specimens

48 

(Holocene)

81

2

1

fragment 

of left 

valve

2

3

66

8

59

8

1

Maximum 

length, 

in mm

145

(USNM 

3622)

94 

(103,

Maury) *

133

(British 

Mus. Nat. 

History 

98047)

110±

88.5,

estimated 

restored 

95

95±

80

119

94

69

(72, 

Maury) is

95±

111

Height in 

percentage 

of length

76-87

87-96

90-92

90±

90±

90±-93±

95-97

85-100

91-96

87-98

90^-95

81

Outline

Inequilateral, ventral 

part of posterior 

margin slightly to 

distinctly extended.

Inequilateral, ventral 

part of posterior 

margin somewhat 

extended.

Inequilateral, ventral 

part of posterior 

margin somewhat 

to strongly extended.

Inequilateral, ventral 

part of posterior 

margin extended

-....do .___ ....__..-.

- do. ._. ..-

--..do .-......_.-

Very variable. Inequilateral to 

subequilateral. Posterior part short to 

long. Ventral part 

of posterior margin 

extended to 

rounded.

Inequilateral to subequilateral, ventral 

part of posterior 

margin slightly to 

moderately extended.

part of posterior 

margin moderately 

to strongly extended.

Inequilateral, ventral 

part of posterior 

margin somewhat 

extended.

Very inequilateral, 

posterior margin 

strongly rounded.

Number 

of ribs

23-27

24-27

25-27

27

25

26

26-28

23-29

25-27

25-27

27-28

25

Noding of ribs, 

other than 

anterior ribs

Ventral part of 

median ribs of 

some shells 

irregularly 

noded.

Ventral part of 

median ribs 

generally irregularly noded.

Ventral part of 

median ribs of 

some shells 

noded.

Ventral part of 

median ribs irregularly noded.

.. ...do-.-. ........

 ..do ....... ...

tral parts of 

median ribs 

noded.

Ventral part of 

median ribs of 

some shells 

noded.

Median ribs generally noded.

...-do ..........

Ventral part of 

median ribs of 

some shells 

noded.

Ventral part of 

median ribs irregularly 

noded.

Height of 

hinge

Low to intermediate

Low to 

high

Intermediate

Inaccessible

Worn and

corroded

High.... .-.

..--do 

Low (14%), 

intermediate 

(19%), 

high 

(67%)

Intermediate

Low to 

high

Inaccessible

Occurrence

Holocene, Baja California 

to northern Peru.2 

Pleistocene, Ecuador,3 

Peru. 2 Pliocene, Carmen 

Island, Gulf of California.*

Caparo clay member of 

Talparo formation, 

Trinidad.s «

Strata of late(?) Miocene 

age in valley of Bio 

Yaque del Norte, 

Dominican Republic.7 8 9

"Carbon Creek," north 

side of Talamanca 

Valley, southeastern 

Costa Bica( US GS 

7841).

Middle part of Gatun

formation. See following description. Identification doubtful.

August Town formation,

Jamaica (USGS 11203).

Cerros de Sal formation,

Barahona Province, 

Dominican Republic 

(USGS 8742)

Hibachero, Piojo and 

Tubara formations 

(middle Miocene) and 

Usiacuri formation 

(late Miocene), Atlantico 

Dept., Colombia.i° " 

Middle Miocene deposits, 

Rio Sinu-RIo San Juan 

area, Rio Atrato area, 

Colombia (USGS 11555, 

11562,11587,11654).

Chiguaje formation (middle Miocene, USGS 

24700) and La Vela 

formation (middle or 

late Miocene), 12 Falcon, 

Venezuela.

San Jose calcareous silt

member and Montserrat glauconitic sandstone member of 

ManzanUla formation, 

Trinidad." "

Azua Province, Dominican Republic (USGS 

8570, 8572, 8760)

Azua Province, Dominican Republic (USGS 

8590).

1 Maury, 1922, p. 32, pi. 3, fig. 13, as Scapharca (Scapharca) grandis.

2 Olsson, 1961, p. 93, pi. 7, figs. 1, la-lc.

s Reinhart, 1943, p. 65, as Anadara (Larkinia) grandis.

4 Hanna and Hertlein, 1927, p. 140, as Area grandis.

5 Maury, 1925, p. 57, pi. 2, fig. 5, as Scapharca (Scapharca) patricia. 

« Rutsch, 1942, p. 214, pi. 8, figs, la, Ib, as Anadara (Larkinia) patricia.

7 Sowerby, 1850, p. 52, as Area patricia.

8 Maury, 1917, p. 173, pi. 27, as Scapharca patricia.

Anadara (Grandiarca) grandis patricia (Sowerby)?

Plate 79, figures 12,13

Large, thick-shelled, height about 90 percent of 

length, inequilateral (umbo at about anterior third of 

length). Posterior margin defective, but ventral part 

apparently extended. Sculptured with 25 ribs, of about 

same width as space between them. Despite corrosion,

9 Pilsbry, 1922, p. 404, pi. 40, fig. 1, as Area grandis.

i» Weisbord, January, 1929, p. 5, pi. 1, fig. 1, as Scapharca grandis colombiensis; p. 8, 

pi. 1, figs. 2, 3, as Scapharca grandis cedraknsis.

11 Anderson, March, 1929, p. 148, pi. 19, fig. 6, pi. 20, fig. 6, pi. 21, fig. 4, as Area 

(Anadara) usiacurii.

1 2 Hodson, Hodson, and Harris, 1927, p. 7, pi. 7, figs. 1, 4, as^rca grandis waringi.

13 Maury, 1925, p. 58, pi. 3, figs. 2, 5, as Scapharca patricia waringi.

n Rutsch, 1942, p. 219, pi. 8, figs. 2a, 2b, as Anadara (Larkinia) waringi.

irregularly arranged, coarse nodes apparent on ventral 

part of anterior and median ribs. Cardinal area very 

wide, corroded. Hinge completely worn away.

Length (incomplete) 88.5 mm (estimated restored 

length 95 mm), height (incomplete), 67.5 mm (estimated restored height 85 mm), diameter about 40 mm 

(figured specimen).
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCTJLIDAE TO MALLEIDAE 513

The illustrated left valve and a fragment of the 

posterior ventral part of a smaller left valve were collected at the same locality as Anadara dolaticosta. In 

addition, the collection includes two fragments of 

Grandiarca too incomplete for identification. All these 

specimens of Grandiarca are battered and corroded. 

Their condition stands in marked contrast to the 14 

well-preserved marine species with which they are 

associated.

Noding of median ribs and distinct extension of the 

ventral part of the posterior margin is more common 

in A. grandis patricia than in A. grandis grandis, although better preservation is needed for satisfactory 

identification. Perhaps the assumed habitat influenced 

the identification.

Area patricia, described, but not illustrated, by Sowerby, was the first of the grandis-\\kz fossils to be 

named. In 1925 the late L. R. Cox, of the British Museum (Natural History), forwarded a cast of the alleged type, actually lectotype, of that species (12828 of 

the Kegister of Geological Society of London Collection). It is a right valve of a much-named small Anadara of the subgenus Rasia, named Area pennelli by 

Gabb. (See p. 506 of present account.) Though it was 

naive to suppose that this is Sowerby's species, I accepted it (Woodring, 1925a). Sowerby was an experienced conchologist. He compared his species with Area 

grandis and he named it Area patricia. There is nothing 

patrician about Area pennelli. For these reasons Weisbord (1929, p. 7) was skeptical about the alleged lectotype, and Kutsch (1942, p. 215) rejected it. On the 

contrary, Anderson (1929, p. 149) proposed anew name, 

Area patriarcha, for the traditional Area patricia.

Charles Davies Sherborn, the meticulous compiler 

of the Index Animalium, registered the Heneken collection, which originally included Area patricia, after 

it was transferred from the Geological Society of London to the British Museum (Natural History). On page 

385 of the original of the Register of the Geological 

Society of London Collection, Foreign Series, he wrote 

the following warning, published in German translation 

byPflug(1961,p.8):

Sowerby certainly drew from these specimens; none of 

the types were marked; the loose papers have been shifted 

about; identification has in many cases been difficult, so 

the searcher must in every case verify my conclusions and 

accept or reject as he thinks proper.

It seems strange that Sherborn identified the small 

species as Area patricia, although, as a matter of fact, 

he added two question marks in the Register.

Two left valves of Area patricia are in the collections 

of Caribbean fossils in the British Museum (Natural 

History) (98047 in Register 19 of Additions to Department of Paleontology, entered in 1879). A strip of 

paper glued to the better of the two reads "Miocene, St. 

Domingo." The Register entry reads "8 bivalves, Miocene, St. Domingo, Col. Heniker [Heneken] Collection." 

Unless grounds are apparent for doubting the authenticity of the Register data, this lot qualifies as the type 

lot, or perhaps what is left of the type lot. The better of 

the two valves has a length of 124 mm, the other, which 

is much worn, is a little larger, 133 mm.

According to Col. Heneken's account (1853, p. 128), 

he found "large Conchifera of the family of Arcacea 

in great abundance; they cover the surface in patches 

of compact seams" on "the sandstone plain of Savaneta 

[Sabaneta]," on the south side of Rio Yaque del Norte 

between Rio Cana and Rio Guayubin. The Maury expedition collected the large arcid on Rio Cana (Maury, 

1917a, p. 25) from strata that are younger than the 

early middle Miocene Cercado formation farther upstream. Their relations to the late middle Miocene 

Gurabo formation are unknown, but they presumably 

were deposited during the regressive stage of the transgression that started with the early Miocene Baitoa 

formation and continued during the middle Miocene, 

and probably are of late Miocene age.

The only USNM Dominican Republic specimens are 

in two lots collected in the foothills of the Cordillera 

Septentrional, on the north side of Rio Yaque del Norte.

Occurrence: Middle part of Gatun formation (middle Miocene), western area, locality 170.

Subgenus Fotiarca Iredale

Iredale, Great Barrier Reef expedition, 192S-29, Scientific Reports, v. 5, no. 6, Mollusca, pt. 1, p. 284, British Museum 

(Natural History), 1939.

Type (orthotype) : Potiarca (pilula) saccula Iredale; that is, a 

subspecies of Area pilula Reeve, living, western Pacific 

Ocean.

Ever since Dall's treatment in 1898 (Dall, 1890-1903, 

p. 633-636,1898) the American fossil and living species 

of Potiarca have been assigned to his subgenus Ounearca, the next subgenus under consideration. I am indebted to my colleague Druid Wilson for pointing out 

that Potiarca is available for American species as well 

as western Pacific species. To be sure, Potiarca and 

Gunearca are more or less similar in several features. 

Both are inequivalve, the sculpture of the two valves 

of both is discrepant, and the ribs of both, with the exception of two Miocene species of Potiarca, are undivided. The outline of both also is similar, although most 

species of Potiarca are less elongate. The cardinal area 

of both is wide and triangular. The progressively 

greater overlap of the left valve progressively greater 

from the anterior end to the posterior end of the ventral 

margin is the most characteristic shell feature of 

Ounearca, whereas the overlap of Potiarca is less pro475-796 O - 73 - 5
514 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

nounced and of uniform extent. The ribs of the left 

valve of Cunearca are wider than those of Potiarca and 

are separated by a narrow space. The cardinal area of 

Cunearca is horizontally striated. Some species of Potiarca have a similar cardinal area, but other species have 

ligament grooves of various shapes, ranging from one 

or two angulated chevrons to as many as four bent or 

wavy continuous, or discontinuous, grooves. Still other 

species include specimens that are only horizontally 

striate and specimens that have ligament grooves. 

Stanley (1970, p. 126, pi. 6, fig. 3) found that Anadara 

chemnitzii a species of Potiarca secretes an unusual 

byssus, consisting of a single thread with a sheet-like 

terminal pad.

Potiarca is widespread and locally exceptionally 

abundant in the Miocene of the Tertiary Caribbean 

province. The earliest are of early Miocene age. In 

southeastern United States, however, the subgenus is 

unknown before late Miocene time. It survives on both 

sides of Panama: Anadara chemnitzii (Philippi) in the 

western Atlantic Ocean and the closely related A. nux 

(Sowerby) in the eastern Pacific.

The fossil species in the present Caribbean region 

are overnamed, especially those of Miocene age. Twentyfive names have been proposed, including six for those 

in the early Miocene Pirabas formation of Brasil and 

the same number for those in the Miocene of the Dominican Republic.

Anadara cumanensis (Ball, 1890-1903, p. 633) is 

identified as a small A. chemnitzii. Though the catalog 

specifies only one specimen, a right and a left valve are 

under the catalog number 115678. The left valve practically agrees with Ball's measurements and is designated the lectotype, and Cumana, Venezuela, is designated the type locality. The left valve from an island 

in Lago de Enriquillo, Dominican Republic, loaned to 

Maury and illustrated by her (1925, p. 70, pi. 5, fig. 4) 

is missing or misplaced. Anadara aff. A. filicata, from 

the Pliocene of Trinidad (Jung, 1969, p. 333, part, not 

pi. 15, fig. 7), also is identified as a small A. chemnitzii. 

The type material of Area limonica (Ball, 1912, p. 2: 

post-glacial "Atlantic muck," Canal Zone) consists of 

three minute, subcircular right valves (length 2.4 to 

3.5 mm). They doubtless are immature A. chemnitzii. 

To designate a lectotype would serve no useful purpose.

Molds from the Toro limestone member of the 

Chagres sandstone are listed as Anadara sp.

Anadara (Potiarca) aff. A. chavezi (Engerrand and TTrbina) 

Plate 72, figure 2

Of medium size, height a little less than length, 

inequilateral. Posterior margin barely rounded, ventral 

part not extended. Right valve sculptured with about

27 ribs, slightly narrower than space between them, 

except at anterior and posterior ends, where they are 

of about same width as space, or a little wider. Anterior 

ribs noded, others smooth. Cardinal area missing.

Length 18 mm, height about 17 mm, diameter about 

7.5 mm (figured specimen).

An almost complete, but defective, right valve is the 

only Potiarca found in the La Boca formation. So far 

as it goes, it is comparable to Anadara chavezi, the next 

species. If it is not that species, it is its immediate 

predecessor.

Occurrence: La Boca formation (early Miocene), locality 116.

Anadara (Potiarca) chavezi (Engerrand and TTrluna) 

Plate 81, figures 1-3, 6, plate 82, figure 5

Area (Scapharca) chavezi Engerrand and Urbina, Soc. Geol. 

Mexicana BoL, v. 6, p. 131, pi. 60, figs. 56-60, 62-65, 1910 

(Miocene, Mexico).

Anadara cf. A. Chavezi (Engerrand and Urbina). Alencaster Y, 

in Rios Macbeth, Asoc. Mexicana Ge61ogos Petroleros BoL, 

v. 4, p. 347, pi. 17, figs. 6, 7, 1952 (Miocene, Mexico).

Scapharca cor-cupidonis Maury, Bull. Am. Paleontology, v. 5, 

no. 29, p. 175, pi. 30, figs. 5-7, 1917 (Miocene, Dominican 

Republic).

Scapharca riocanensis Maury, Bull. Am. Paleontology, v. 5, 

no. 29, p. 176, pi. 30, figs. 3, 4, 1917 (Miocene, Dominican 

Republic).

Area perfaceta Pilsbry and Johnson, Acad. Nat. Sci. Philadelphia Proc., v. 69, p. 190, 1917 (Miocene, Dominican Republic). Pilsbry, Acad. Nat. Sci. Philadelphia Proc., v. 73, 

p. 407, pi. 39, figs. 17-20, 1922 (Miocene, Dominican 

Republic).

Area pomponiana Pilsbry and Johnson, Acad. Nat. Sci. Philadelphia Proc., v. 69, p. 190, 1917 (Miocene, Dominican Republic). Pilsbry, Acad. Nat. Sci. Philadelphia Proc., v. 73, 

p. 407, pi. 42, figs. 4-6, 1922 (Miocene, Dominican 

Republic).

Barbatia (Diluvarca) opthanta Woodring, Carnegie Inst. Washington Pub. 366, p. 50, pi. 5, figs. 14, 15, 1925 (Miocene, 

Jamaica; immature).

?Anadara (Cunearca) sp., Alancaster-Ibarra, in Masson and 

Alencaster-Ibarra, Asoc. Mexicana Ge61ogos Petroleros 

BoL, v. 3, p. 204, fig. 4, 1951 (Miocene, Mexico).

Of medium size to moderately large. Left valve larger 

than right. Umbo of smallest shells faintly sulcate. Outline variable, height somewhat less than length to 

somewhat more, moderately unequilateral. Posterior 

margin of mature shells slightly rounded to obliquely 

subtruncated, ventral part slightly to distinctly extended. Small shells (length 5 to 8 mm) generally subcircular; smallest (length<5 mm) invariably subcircular, though still slightly inequilateral. Sculptured with 

24 to 31 ribs (generally 26 to 28, with peak at 26). Median ribs of right valve slightly narrower than space between them, or of about same width; anterior ribs 

strongly noded, posterior ribs less strongly noded, median ribs generally smooth, exceptionally more or less
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 515

noded on ventral part. Ribs of left valve wider than 

space between them; all ribs noded, but nodes subdued 

or absent on outermost part of posterior ribs. Cardinal 

area wide; horizontally striate, ligament grooves present or absent; if present, consisting of one or two angulated or bent chevrons, or bent or wavy, continuous or 

discontinuous, irregular grooves.

Length 23.2 mm, height 20 mm, diameter 10.1 mm 

(figured right valve of medium size). Length 30.5 mm, 

height 26.4 mm, diameter 14.6 mm (figured large left 

valve).

Type: Location unknown.

Type locality: Zuluzum, a folk name for a locality 

on Rio Chacamas, near Palenque, northeastern Chiapas, 

Mexico, deposits of middle Miocene age.

Anadara chavezi is represented in the Gatun formation by 265 specimens, two of which are articulated. 

The distribution in the three parts of the formation 

is very uneven, as shown by the following table.

Distribution of Anadara (Potiarca) chavezi

Gatun formation

Upper part, eastern area ___ __ _ _ _ _ __ .

Middle part, western area. _ _ _ ___ _ __ .

Lower part- _ _ _ __ _ __ _ _ __ __ _.

Number of 

specimens

1

12

38

214

The distribution suggests that A. chavezi, like 

A. chemnitzii, preferred shallow water. The Gatun 

formation represents deposition in progressively deeper 

water in the eastern area, from the lower part upward.

All the specimens from the lower part are small or 

of medium size, ranging in length from 1.7 to 26 mm 

(pi. 81, figs. 2, 6, pi. 82, fig. 5). The collections from the 

middle part include shells that are small, of medium 

size, and four decidedly larger, two of which are illustrated (pi. 81, figs. 1, 3). The 27 valves from locality 

161c are the only ones showing a graded size series from 

large to very small. The single valve from the upper 

part is small and short (length 14.4 mm, height 

15.3 mm).

The numerous specimens from the lower part are 

fairly uniform in outline, whereas those from the middle part show a range from elongate (pi. 81, fig. 1) to 

short (pi. 81, fig. 3). The ventral part of the median ribs 

of 12 percent of right valves of suitable size (length > 

10 mm) are more or less noded, but not as strongly noded 

as the median ribs of left valves. A noded right valve 

is shown on plate 81, figure 6.

A collection from a middle Miocene locality 3 km 

northeast of Santa Rosa, in the Isthmus of Tehuantepec 

(USGS 9995, 23737), contains perhaps tens of thousands of A. chavezi. The locality is about 350 km west

of the type locality. A casual inspection indicates that, 

like those from the lower part of the Gatun formation, 

they are fairly uniform in outline and size. The maximum length is about 25 mm. Small shells are subcircular. The ribs of a small sample number 24 to 29, with 

peaks at 24 and 26. No right valve examined has distinct 

nodes on median ribs. The cardinal area is horizontally 

striate only or bears as many as four bent ligament 

grooves. The collection, made by Brace Wade in 1920, 

was divided between the U.S. National Museum and 

The Johns Hopkins University. Both parts are now in 

the National Museum. The molluscan fauna of an estimated 450 species is being monographed by Sra. Dra. 

Carmen Perrilliat de Perez, of the Institute de Geologia 

of the Universidad Nacional Autonoma de Mexico.

Several hundred topotypes of A. corcupidonis, from 

the Cercado formation of the Dominican Republic 

(USGS 8525), are available. They also are fairly uniform in outline and size, and small valves are subcircular. The maximum length is 26 mm and the rib count 

is 24 or 25. As in the Santa Rosa collection, the median 

ribs of the right valves examined are not distinctly 

noded. All the large valves examined bear ligament 

grooves: one or two angulated chevrons, or as many 

as three bent, wavy, or even zigzag grooves.

It might be expected that a Gatun species of Potiarca 

would be A. pittieri (Dall), based on middle Miocene 

fossils from southeastern Costa Rica (Dall, 1912, p. 9; 

1925, p. 5, pi. 17, fig. 7; Olsson, 1922, p. 192, pi. 24, 

figs. 2-6). Dall selected, from several hundred specimens collected at USGS locality 5882h on Rio Banano, 

five valves as types. The left valve he later illustrated 

is herewith designated the lectotype. The median ribs 

of right valves are almost invariably noded, but on a 

few the nodes are greatly suppressed. A. hindsi (Olsson, 1922, p. 193, pi. 24, figs. 7-9) was based on even 

greater suppression. The chief difference, however, between A. pittieri and A. cliavezi lies in the elongate outline of small shells of A. pittieri.

Occurrence: Lower, middle, and upper parts of Gatun 

formation (middle Miocene). Lower part, localities 137, 

137a, 138, 138a, 138b, 138c, 138d, 138e, 138f, 138g. Middle part, eastern area, localities 139 (Anadara sp., 

molds), 139c, 143 (Anadara sp.), 144 (Anadara sp., 

molds), 144a (Anadara sp., molds), 147b (Anadara sp., 

minute), 155, 155a, 155c, 159d; western area, localities 

160 (Anadara sp., mold), 160d, 161, 161c, 161d, 162, 

162a, 169 (Anadara sp.), 170 (Anadara sp., minute). 

Upper part, eastern area, locality 177e. Cercado formation (middle Miocene), Dominican Republic. Bowden formation (middle Miocene), Jamaica. Deposits of 

middle Miocene age, Chiapas, Mexico.
518 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

the Springvale formation, where it reached a larger size 

than in the Pliocene deposits. The subsurface species 

from southeastern United States N. gardnerae (MacNeil, 1938, p. 37, pi. 6, figs. 16, 17) was based on two 

small valves recovered from a well in Texas. Druid 

Wilson called my attention to two larger valves (length 

18.1 and 19.8 mm) from a well in the lower part of 

Plaquemines Parish, Louisiana (USGS 9279). As realized by MacNeil, N. gardnerae is closely related to N. 

sTieldoniana; it may eventually be found to be that 

species.

Area (Scapharca) cJiaranensis (Spieker, 1922, p. 109, 

pi. 5, fig. 15, an inadequate illustration), from the lower 

part of the Zorritos formation of Peru, suggests a species of the subgenus Eontia, an earlier occurrence than 

any in southeastern United States.

Noetia (Noetia) reversa macdonaldi (Dall)

Plate 81, figures 12,13, plate 82, figures 1, 4

Area (Noetia) macdonaldi Dall, Smithsonian Misc. Oolln., v. 59,

no. 2, p. 9,1912 (Miocene, Costa Rica). Dall, U.S. Natl. Mus.

Proc., v. 66, art. 17, p. 5, pi. 17, fig. 9, 1925 (Miocene, Cbsta

Rica). Hodson, Hodson, and Harris, Bull. Am. Paleontology,

v. 13, no. 49, p. 3, 1927 (Miocene, Venezuela). Anderson,

California Acad. Sci. Proc., 4th ser., v. 18, no. 4, p. 147,

1929 (Miocene, Colombia). Barrios, Colombia Servicio Geol.

Nac., Bol. Geol., v. 6, nos. 1-3 (Informe 1082), p. 228, pi. 1,

fig. 3,1960 (Miocene, Colombia). 

Area macdonaldi Dall, Olsson, Bull. Am. Paleontology, v. 9, no.

39, p. 194 (assigned to subgenus Noetia), pi. 25, figs. 4, 5,

1922 (Miocene, Costa Rica). 

Noetia macdonaldi MaoNeil, U.S. Geol. Survey Prof. Paper 189-

A, p. 35, pi. 6, figs. 10-13, 1938 (Miocene, Costa Rica,

Colombia). 

Area macdonaldi subreversa Olsson, Bull. Am. Paleontology, v.

9, no. 39, p. 194 (in discussion), pi. 25, figs. 6, 7, 1922

(Miocene, Costa Rica). 

Noetia, macdonaldi alta MacNeil, U.S. Geol. Survey Prof. Paper

189-A, p. 36, pi. 6, figs. 1, 2, 8, 9, 1938 (Miocene, Costa

Rica.) 

Noetia macdonaldi truncata MacNeil, U.S. Geol. Survey Prof.

Paper 189-A, p. 36, pi. 6, figs. 3, 4, 1938 (Miocene, Colombia ). 

Noetia colombiana MacNeil, U.S. Geological Survey Prof. Paper

189-A, p. 34, pi. 5, figs. 10, 11, 1938 (Miocene, Colombia). 

Noetia matiryae MacNeil, U.S. Geol. Survey Prof. Paper 189-A,

p. 34, pi. 5, figs. 18, 19, 1938 (Miocene, Colombia). 

Noetia ecuadoria MacNeil, U.S. Geol. Survey Prof. Paper 189-A,

p. 33, pi. 5, figs. 12, 13, 20, 1938 (Miocene, Ecuador). 

Noetia (Noetia) ecuadoria MacNeil, Olsson, Neogene mollusks

from northwestern Ecuador, Paleontological Research Inst.,

p. 32, pi. 2, fig. 10,1964 (Miocene, Ecuador). 

Noetia dauleana Marks, Bull. Am. Paleontology, v. 33, no. 139,

p. 52, pi. 1, figs. 7-9,1951 (Miocene, Ecuador). 

Noetia dauleana paraguanensis Jung, Bull. Am. Paleontology,

v. 49, no. 223, p. 434, pi. 53, figs. 10, 11, 1965 (Miocene,

Venezuela).

Moderately large, ratio of height to length variable 

(75 to 91 percent). Posterior margin obliquely truncated or subtruncated, ventral part strongly to slightly

extended, moderately inequilateral. Umbo moderately 

high to high, umbonal area relatively narrow to wide. 

Degree of angularity of posterior umbonal slope variable, posterior area flat to slightly concave. Sculptured 

with 30 to 38 low, flat ribs (generally 32 to 35). Eibs 

on main part of shell narrower than space between 

them, those at anterior and posterior ends wider than 

space. An interstitial thread (exceptionally two) generally present between ribs on posterior area near angulated posterior unbonal slope, or between few ribs on 

both sides of slope, exceptionally only between few 

ribs in front of slope. Exaggerated growth lamellae of 

variable distinctness convex upward on ribs and concave upward in space between ribs. Vertically striated 

ligamental part of cardinal area in front of umbo, short 

posterior part set off from main part of shell by groove 

or shelf.

Length 46.5 mm, height 37.7 mm, diameter 19.5 mm 

(figured larger left valve, largest specimen).

Type material: Lectotype, herewith designated, 

USNM 214344.

Type locality: USGS 5882m, Eio Banano, Limon 

Province, Costa Rica, middle Miocene.

This Noetia occurs in the lower and middle parts of 

the Gatun formation, but is nowhere abundant. Even 

the small sample of 19 complete specimens shows the 

variability of features on which species and subspecies 

have been based: height of umbo, width of umbonal 

area, extension of ventral part of posterior margin, degree of angularity of posterior umbonal slope, and 

presence or absence of interstitial threads near the posterior umbonal slope. The illustrated larger left valve 

(pi. 81, figs. 12, 13) is the largest of the Gatun fossils. 

The illustrated smaller left valve (pi. 82, fig. 4) has 

the features of N-. 'macdonaldi alta; that is, a high ratio 

of height to length, high umbo, and narrow umbonal 

area. The illustrated right valve (pi. 82, fig. 1) is 

elongate, and its umbo is low. It is similar to the type 

of N. coloinbiana, but not all the valves in the type lot 

of that form are so elongate.

After extracting some minute valves, Dall selected as 

types of N. macdonaldi the entire lot of 12 valves collected by MacDonald at locality 5882m on Rio Banano. 

The right valve (length 55.6 mm) he later illustrated, 

reduced almost one-half, was accepted as the holotype 

by MacNeil, but is now designated the lectotype. It is 

almost twice as large as the largest of the remaining 

syntypes and also the largest of any specimens in eight 

other collections from Rio Banano available to Dall. A 

comparable specimen from Colombia has been illusstrated (MacNeil, 1938, pi. 6, fig. 11). Those two are 

the only large ones in USNM collections. The Costa 

Rican fossils are variable in outline. One of the re-
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 519

maining syntypes (length 25.5 mm, height 23.8 mm) 

has the outline of N. macdonaldi alta.

N. macdonaldi and the cited synonyms are so similar 

to the living N. reversa (Maury, 1922, p. 9, pi. 1, figs. 7, 

11; Olsson, 1961, p. 101, pi. 10, figs. 1, la, Ib) that it may 

be a strained interpretation to distinguish them, even at 

the subspecific level. Of 50 specimens of the nominate 

subspecies in USNM collections three have a decidedly 

extended outline; about five percent show interstitial 

threads; and a posterior nonligamental part of the 

cardinal area is indistinguishable, or very narrow. The 

posterior umbonal slope of immature valves of the nominate subspecies (length 25 mm) is more sharply angulated than that of Gatun valves of the same size, but 

remaining syntypes of N. macdonaldi of the same size 

are as sharply angulated as living shells. It is evident 

that the fossils present a greater range of variation than 

the nominate subspecies, and that is the chief basis for 

classifying A. macdonaldi and its synonyms as a subspecies of N. reversa. Olsson's comments (1961, p. 102; 

1964, p. 32) are appropriate.

Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, localities 137a, 

138a, 138c, 138f. Middle part, eastern area, localities 

146,155, 155a; western area, localities 160,170. Early to 

late Miocene deposits Colombia. Cantaure formation 

and other middle Miocene deposits, Falcon, Venezuela. 

Middle Miocene deposits, Limon Province, Costa Kica. 

Daule and Angostura formations (middle Miocene), 

Ecuador.

Family G1YCYMEBJDIDAE 

Genus Glycymeris da Costa

da Costa, The British Conchology, p. 168,1778.

Type (tautotype) : Glycymeris orUcularis da Costa ( Area

glycymeris Linn6), living, northern eastern Atlantic Ocean

and Mediterranean Sea.

Submenus Glycymeris s.s.

Glycymeris (Glycymeris) cf. G. caracoli Anderson 

Plate 69, figure 18

Of medium size, subcircular, umbo median. Dorsal 

margins sloping. Traces of weak ribbing on ventral 

part of internal molds.

Length 25 mm, height 25.3 mm, diameter 7.5 mm (figured specimen).

The outline and what is shown of the ribbing of 

seven internal molds, from limestone of the Gatuncillo 

formation in Madden basin, suggest Glycymeris caracoli (Anderson, 1928, p. 21, pi. 1, fig. 9; Clark, in 

Clark and Durham, 1946, p. 54, pi. 2, figs. 9-11, 13), a 

late Eocene Colombian species.

Occurrence: Gatuncillo formation (late Eocene), localities 9,11,12.

Glycymeris (Glycymeris) carbasina Brown and Pilsbry

Plate 79, figures 9,10, plate 81, figures 9,10 

Glycymeris carbasina Brown and Pilsbry, Acad. Nat. Sci.

Philadelphia Proc., v. 63, p. 363, pi. 28, fig. 9, 1911 (Miocene,

Canal Zone). Olsson, Bull. Am. Paleontology, v. 9, no. 39,

p. 179, pi. 19, figs. 1, 2, 5, 1922 (Miocene, Costa Rica). 

Glycymeris carbasina Brown and Pilsbry?, Anderson, California

Acad. Sci. Proc., v. 18, no. 4, p. 152, 1929 (Miocene,

Colombia). 

Pectunculus (Axinaea) gatunensis n. f., aff. Axinaea albolineata

Lischke, Toula, K. K. Geol. Reichsanstalt Jahrb., v. 61, p.

493, pi. 31, fig. 2, 1911 (Miocene, Canal Zone).

Moderately large, subcircular, equilateral, umbo median, tip of umbo slightly opisthogyrate. Dorsal margin 

short, horizontal, roimding into anterior and posterior 

margins. Umbo of unworn shells and small immature 

shells sculptured with many low, narrow ribs, generally 

a little wider than space between them. At later stage, 

fine closely spaced radial striae superimposed on ribs, 

which gradually become still lower, and on space between them. Fine, closely spaced concentric striae appearing at very early stage, the two sets of striae forming almost microscopic decussated surface. Main ribs 

absent near dorsal margins, except on umbo. Cardinal 

area narrow, amphidetic, symmetric or slightly asymmetric on mature shells, asymmetric on most immature 

shells, anterior part longer than posterior.

Length 42.7 mm, height 40.5 mm, diameter 13.2 mm 

(larger figured specimen, largest specimen).

Type material: Lectotype, herewith designated, the 

specimen illustrated by Brown and Pilsbry, the largest 

of four in the type lot, Acad. Nat. Sci. Philadelphia 

1745.

Type locality: Gatun Locks excavation, Canal Zone, 

middle part of Gatun formation.

The description is based on 28 specimens from the 

Gatun formation. Though the species ranges 'through 

the formation, the only valve from the lower part is 

minute (length 3.5 mm). Five imperfect valves, four of 

which are large, from the La Boca formation also are 

identified as Glycymeris carbasina.

The lectotype is immature (length 18 mm), representing a stage before the ribs become very low and when 

radial striae appear only near the ventral margin. Olsson recorded a length of 55 mm for large Costa Rican 

shells. The largest Colombian shell in USNM collections 

has a length of 50 mm, but an incomplete valve suggests almost 65. The ventral part of the posterior margin 

of the larger illustrated valve is nicked, not subtruncated. The asymmetric cardinal area of a well-preserved 

immature valve is shown on plate 79, figure 9.

This species is identified along the southwest border 

of the Caribbean Sea: in southeastern Costa Rica, 

Panama and Colombia. It is especially abundant in the 

Piojo formation of Colombia. Its age range is early to
520 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

middle Miocene. The sculpture is the same as that of 

G. jamaicensis (Dall, 1890-1903, p. 608, 1898; Woodring, 1925, p. 24, pi. 2, figs. 1-3; Miocene, Jamaica), but 

the ventral part of the posterior margin of that species 

is obliquely subtruncated (specified as anterior margin in the 1925 account). It would be better to treat 

6r. jamaicensis as a Miocene subspecies of G. undata 

(Linne), now living in the Caribbean region. The 

Miocene subspecies is distinguished by its smaller size 

and more strongly ribbed umbo.

Occurrence: La Boca formation (early Miocene), localities 99g, 116a, 119c. Gatun formation (middle Miocene). Lower part, locality 138c. Middle part, eastern 

area, localities 155,155a, 155b, 159; western area, locality 

169. Upper part, eastern area, localities 171,172,177b; 

western area, locality 182. Early Miocene deposits, Rio 

San Juan-Rio Sinu area, Bolivar Dept., Colombia, Middle Miocene deposits, Limon Province, Costa Rica. Hibachero, Piojo, and Tubara formations (middle Miocene) , Atlantic© Dept., Colombia.

Subgenus Tucetona Iredale

Iredale, Australian Mus. Records^ v. 18, p. 202, 1931. 

Type (orthotype) : Glycymeris flabellatus Tenison-Woods [Pectunculus flabellatus], living, South Australia.

It seems strange that no species of Tucetona is in collections from the lower part of the Gatun formation. 

The Gatun specimen, or specimens, recorded by Brown 

and Pilsbry (1911, p. 364) as Glycymeris acuticostata 

(Sowerby) were not found.

Group of Glycymeris subovata

The group of Glycymeris subovata, characterized by 

wide, almost flat ribs, separated by a linear, or slightly 

wider, groove, is widespread in the Miocene of southeastern United States from Virginia to Florida, and is 

found also in the Caribbean region. It became extinct 

at the end of Miocene time.

Glycymeris (Tucetona) epacra Woodring, n. sp. 

Plate 81, figures 7, 11

Glycymeris lloydsmithi Pilsbry and Brown, Olsson, Bull. Am. 

Paleontology, v. 9, no. 39, p. 181, pi. 25, figs. 8-10, 1922 

(Miocene, Costa Rica), Weisbord, Bull. Am. Paleontology, 

v. 14, no. 54, p. 10, pi. 1, figs. 12, 13, 1929 (Miocene, Colombia). Anderson, California Acad. Sei. Proc., v. 18, no. 4, 

p. 152, 1929 (Miocene, Colombia).

Of medium size, trigonal-ovate, um'bonal area narrow, 

its margins steeply sloping. Height slightly greater than 

lengtih, posterior margin slightly to distinctly extended. 

Umbo worn. Sculptured with 'about 28 to about 31 very 

low, almost flat ribs, separated by linear groove, except 

near upper margins, where space between them is 

slightly wider than elsewhere. Ribs fading out adjoining upper margins, less distinct near ventral margin of 

mature shell. Cardinal area short, narrow, amphidetic.

Length 33.7 mm, height 36.2 mm, diameter 11 mm 

(type, largest specimen).

Type :USNM 646880.

Type locality: 182a (USGS 8488, Caribbean coast 

east of San Miguel [Rio Miguel], station 25 plus 400 

feet (120 meters), Panama), Upper part of Gatun 

formation.

Glycymeris epacra is repersented by five immature 

valves from the middle part of the Gatun formation, 

two immature from the upper part in the eastern area, 

and six, including mature valves, from the upper part 

in the western area. Most of tlhose from the western area, 

including the type, are more or less worn. The illustrations show the range of variation in outline.

The typical form of G. subovata (Say) (Gardner, 

1926-47, p. 35, pi. 8, figs. 3-8, 1926) and G. drymanos 

Gardner (1926-47, p. 36, pi. 9, figs. 1, 2,1926), which is 

extraordinarily abundant in the Oak Grove sand member of the Shoal River formation of Florida, are more 

subcircular than G. epacra.

There is a possibility that G. epacra is G. lloydsmithi 

(Pilsbry and Brown, 1917, p. 39, pi. 6, fig. 6; Miocene, 

Colombia), as Olsson, Weisbord, and Anderson thought. 

The type, and only specimen, however, is badly worn 

and the type locality so indefinite that topotypes cannot be recovered.

Occurrence: Middle and upper parts of Gatun formation (middle Miocene). Middle part, western area, localities 168, 169. Upper part, eastern area, locality 173; 

western area, localities 182, 182a. Middle Miocene deposits, Limon Province, Costa Rica; Atlantico Dept., 

Colombia.

Group of Glycymeris pectinata

Molds from the lower member of the Alhajuela formation and the Toro limestone member of the Chagres 

sandstone are listed as Glycymeris sp.

Glycymeris (Tucetona) pectinata canalis Brown and Pilsbry 

Plate 81, figures 4, 5, 8

Glycymeris canalis Brown and Pilsbry, Acad. Nat. Sci. Philadelphia Proc., v. 63, p. 364, pi. 28, fig. 10, 1911 (Miocene, 

Canal Zone). Nicol, Jour. Paleontology, v. 19, p. 622, pi. 85, 

figs. 1, 2, type [lectotype], (Miocene, Canal Zone).

fGlycymeris canalis Brown and Pilsbry, Hodson, Hodson, and 

Harris, Bull. Am. Paleontology, v. 13, no. 49, p. 15, 1927 

(Miocene, Venezuela). Barrios, Colombia Serv. Geol. Nac., 

Bol. Geol., v. 6, nos. 1-3 (Informe 1082), p. 235, pi. 3, figs. 

6, 7, 1960 (Miocene, Colombia).

fPectunculus spec. ind. (n. sp?) Toula, K. k. Geol. Reichsanstalt 

Jahrb., v. 58, p. 718, pi. 28, fig. 13, 1909 (Miocene, Canal 

Zone).

Not Glycymeris canalis Brown and Pilsbry, Olsson, Bull. Am. 

Paleontology, v. 9, no. 39, p. 177, pi. 18, figs 2-7, 1922 (Miocene, Costa Rica) ; = G. secticostata Nicol.
GASTROPODS, SCAPHOPODS, PELE;CYPOI>S: NUCULIDAE TO MALLEIDAE 521

Not Glycymeris canalis Brown and Pilsbry, Maury, Bull. Am. 

Paleontology, v. 10, no. 42, p. 31, pi. 18, figs. 3, 4, 1925 

(Miocene, Trinidad).

Of medium size, trigonal-ovate, umbonal area narrow, 

its margins sloping. Height equal to length, or slightly 

greater than length, posterior margin slightly extended. 

Sculptured with 22 to 31 (generally 30) low, arched 

primary ribs of moderate width, wider than space between them; space between ribs exceptionally very narrow. Ribs generally fading out near upper margins. 

Minor secondary sculpture appearing at height of 10 

to 20 mm: an interstitial narrow rib or thread in some 

spaces between ribs, especially anterior ribs, generally 

at edge of space immediately adjoining primary rib, 

exceptionally in middle of space. On unworn surfaces 

fine, closely spaced concentric threads on ribs and in 

space between them. "Resting stages" conspicuous on 

many shells, especially those of large size. Cardinal 

area short, narrow, amphidetic.

Length 34.6 mm, height 36 mm, diameter 11 mm 

(figured right valve).

Type material: Lectotype, herewith designated, the 

specimen illustrated by Brown and Pilsbry, the largest 

of four in the type lot, Acad. Nat. Sci. Philadelphia 

1747.

Type locality: Gatun Locks excavation, Canal Zone, 

middle part of Gatun formation.

Though the upper part of the Gatun formation 

yielded two immature valves of Glycymeris pectinata 

canalis, the remaining 31 specimens identified without 

qualification are from the middle part. Collections from 

the Gatun Third Locks excavation are the most satisfactory and include the only fully mature valves. 

Eighteen specimens in one of those collections (155b) 

represent a growth series from a length of 9.8 to 35 mm. 

Eight valves from the La Boca formation, ranging in 

length from 9 to 21.8 mm, and an external mold from 

the lower member of the Alhajuela formation (length 

12.6 mm) are doubtfully identified as G. pectinata 

canalis. The ribs of another small La Boca valve, listed 

as Glycymeris sp., are somewhat angular.

The lectotype is immature (length 14.6 mm), at a 

growth stage preceding the appearance of minor secondary sculpture. Plate 81, figure 5, shows an immature left valve that has a very narrow space between 

primary ribs and a faint trace of an interstitial thread 

between some anterior ribs.

The middle Miocene Glycymeris in southeastern 

Costa Rica that has arched, instead of angular, ribs is 

accepted as G. pectinata canalis. Only a few immature 

valves are in Rio Banano TJSNM collections (TJSGS 

5882g, 5882h). Typical mature shells are found in middle Miocene deposits on the Pacific side of Panama in 

Chiriqui Province (USGS 7955). Despite unillustrated

records, it is doubtful whether the typical form occurs 

in Colombia and Venezuela. On the ventral part of the 

shell of G. canalis colombiensis (Weisbord, 1929, p. 11, 

pi. 2, figs. 3, 4) the ribs are separated by linear grooves.

As recognized by Brown and Pilsbry, G. pectinata 

canalis is closely related to G. pectinata pectinata 

(Gmelin), living in the Caribbean region. Many large 

specimens of the nominate subspecies show minor secondary sculpture like that of the fossils. The nominate 

subspecies, however, is somewhat smaller (maximum 

length 32 mm in USNM collections); in fact, most lots 

are decidedly smaller. A very narrow space between ribs 

is the prevailing sculpture among living shells.

Occurrence: La Boca formation (early Miocene; 

identication doubtful), localities 115,116a. Lower member of Alhajuela formation (early Miocene; identification doubtful), locality 82 (sp.), 82a. Middle and upper 

parts of Gatun formation (middle Miocene). Middle 

part, eastern area, localities, 144d, 147b, 155,155a, 155b; 

western area, localities 160, 160c. Upper part, eastern 

area, locality 173. Middle Miocene deposits, Limon 

Province, Costa Rica. Middle Miocene deposits, Chiriqui 

Province, Panama.

Group of Glycymeris arctata

A group of species typified by Glycymeris arctata 

(Conrad) (1848, p. 1£:5, pi. 13, fig. 24; Oligocene, Mississippi) is unknown in southeastern United States later 

than early Miocene time. It is represented in the Tampa 

limestone, of that age, by G. lamyi (Dall, 1915, p. 122, 

pi. 20, figs. 11, 13; G. lamyi tampae Mansfield, 1937, p. 

190, pi. 10, figs. 4, 6, 7, is a synonym.) On the contrary, 

the group survived in the Caribbean region until late 

Miocene time, but left no descendants in western 

Atlantic or eastern Pacific waters.

Glycymeris (Tucetona) secticostata schencki Nicol 

Plate 72, fig are 1, plate 75, figures 6, 7

Glycymeris schencki Niccl, Jour. Paleontology, v. 21, p. 349, pi. 

50, figs. 1-6,1947 (Miocene, Canal Zone).

Moderately small, trigonal-ovate, umbonal area narrow, its margins sloping. Height slightly less to slightly 

greater than length, posterior margin slightly extended. 

Umbo sculptured with 19 to 26 arched primary ribs of 

uniform width and spacing, or partly irregular in width 

and spacing. Ribs of about same widths as space between 

them, or narrower than space, exceptionally wider than 

space. At height of 4 to 12 mm, primary ribs split into 

two parts, eventually on large shells into three or four 

parts. At about same stage as splitting of ribs, interstitial rib or thread appearing in space between primary 

ribs, eventually two or three. Interstitial rib exceptionally as wide as branches of primary ribs on main part of 

shell. One to five primary ribs adjoining upper margins
522 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

not split. Fine closely spaced concentric threads in space 

between ribs and on unworn ribs. Cardinal area short, 

narrow, amphidetic.

Length 24.5 mm, height 23.3 mm, diameter 7.2 mm 

(largest figured specimen, a topotype).

Type: Stanford Univ. 7880.

Type locality: 173 (Stanford Univ. 2654, Panama 

Railroad realinement [Third Locks realinement], cut 

about % mile (1 km) north of north end of Gatun Third 

Locks excavation, Canal Zone), upper part of Gatun 

formation.

All of the 11 Gatun specimens of this highly sculptured G-lycymeris in USNM collections were found in 

the upper part of the Gatun formation in the eastern 

area. Nicol, however, recorded one from the lower part, 

and another from the middle part. It occurs also in the 

La Boca formation and the Chagres sandstone. In the 

La Boca 21 were collected at locality 116a (length 10 to 

20.8 mm), many of which are more or less worn, and a 

large, poorly preserved one (estimated restored length 

29.5 mm) at locality 119. One of the better preserved 

valves from locality 116a is illustrated (pi. 72, fig. 1). 

It is exceptional in having, on the main part of the 

shell, interstitial ribs of the same width as branches of 

the primary ribs. A Gatun shell, on which the secondary sculpture appears at a later stage than on others is 

shown on plate 75, figure 6. The Chagres fossils consist 

of two external molds.

At an early stage the type of G. secticostata secticostata (Nicol, 1945, p. 623, pi. 85, fig. 3; the specimen illustrated as G. canalis, variety, by Olsson, 1922, p. 178, 

pi. 18, fig. 4) is sculptured with 25 ribs, which are split 

at a height of 15 mm. Four other available specimens, all 

illustrated by Olsson and designated as paratypes by 

Nicol, have about the same number. In this small sample 

the stage at which the ribs are split and interstitial ribs 

appear varies from a height of 15 to 22 mm. The only 

significant differences between the nominate subspecies 

and G. secticostata schencM lie in the angular or subangular primary ribs of the nominate subspecies, as 

compared with the arched ribs of the Canal Zone subspecies, and in the later appearance of rib-splitting in 

the nominate subspecies.

The nominate subspecies occurs also in the late 

Miocene Limon formation of the Bocas del Toro area. 

Panama (USGS 8345, 8495, 8500).

So far as size is concerned, the group of G. arctata 

culminated in G. usiacurii (Anderson, 1929, p. 153, pi. 

22, figs. 3, 4), which occurs in middle Miocene deposits 

in Venezuela and in the late Miocene Usiacuri formation of Colombia. It is the largest species of the group, 

reaching a length of 47 mm in Colombia. G. lamyi Dall 

(Anderson, 1929, p. 152, pi. 22, figs. 7, 8), G. lloydsmitU

striatidenta (Nicol, 1945, p. 624; substitute name for 

G. lloydsmithi multicostata Weisbord, 1929, p. 10, pi. 2, 

figs. 1, 2, not Pectunculus [G-lycymeris] multicostatue 

Sowerby, 1833), G. canalis democraciana F. and H. 

Hodson (in Hodson, Hodson, and Harris, 1927, p. 17, 

pi. 2, figs. 2, 5, pi. 3, fig. 2), and G. aff. G. democraciana 

(Jung, 1965, p. 437, pi. 54, figs. 2, 5, 6) are synonyms 

of G. usiacurii. The affinities of G. lloydsmithi are mentioned under G. epacra.

Occurrence: La Boca formation (early Miocene), 

localities 116a, 119. Lower, middle, and upper parts of 

Gatun formation (middle Miocene). Lower part, locality 138a (Nicol's record). Middle part, eastern area, 

locality 155 (Nicol's record). Upper part, eastern area, 

localities 171, 173, 176a, 177b. Chagres sandstone (late 

Miocene), locality 202.

Family MYTILIDAE

Aside from a species of Mytilus and the genus 

 Cren&lla, mytilids are meagerly represented in the 

faunas under consideration.

Genus Mytilus Linne

Linne, Systema naturae, 10th ed., p. 704, 1758.

Type (logotype, An ton, Verzeichniss der Conchy lien, p. 17,

1839) : Mytilus edulis Linn6, living, eastern and western

North Atlantic Ocean.

Mytilus canoasensis vidali Ferreira and Cunha

Plate 73, figures 1,4 

Mytilus sp., Hedberg, Geol. Soc. America Bull., v. 48, p. 2024,

pi. 8, fig. 6, 1937 (Miocene, Venezuela).

Mytilus vidali Ferreira and Cunha, Mus. Paraense Emilio Goeldi 

Bol., n. ser., Geol., no. 8, p. 22, pi. 2, figs, la, Ib, 1959 (Miocene, 

Brasil).

Moderately large, height 45 to 53 percent of length. 

Umbo at extreme anterior end. Umbonal swelling close 

to ventral margin. Ventral margin slightly concave, 

apex of concavity at middle of shell; dorsal margin 

broadly and strongly arcuate; posterior margin narrowly arcuate. Exterior apparently marked only by 

growth lines, some of which are impressed on some internal molds. Impressions of resilial-ridge pits on two 

molds. Other internal features unknown.

Length 77 mm, height 34.7 mm, diameter (reduced 

by crushing) 9 mm (larger figured specimen).

Type: 4773, Mus. Nacional, Univ. Fed. Rio de Janeiro.

Type locality: Colonia Pedro Teixeira, 2.5 km north 

of Capanema, Para, Brasil, Pirabas formation.

The Culebra formation at locality 106 yielded some 

30 internal molds of a mytilid ranging in length from 

9.5 to 77 mm. The larger illustrated specimen (pi. 73, 

fig. 4) is the only large one. Most of the others are small, 

but three are of intermediate size, one of which is illustrated (pi. 73, fig. 1). It shows the impression of pits 

on part of the resilial ridge, although they do not show
GASTROPODS, SCAPHOPODS, PELE,CYPODS: NUCULIDAE TO MALLEIDAE 523

on the photograph. On one of the others of intermediate 

size the pits extend along a considerable length of the 

resilial ridge. A small mold from the La Boca formation, two small molds from the lower member of the 

Alhajuela formation, and a small mold from the middle 

part of the Gatun formation are identified as the Culebra form. The Gatun specimen shows the impression of 

pits on the anterior part of the resilial ridge.

Though the internal features, other than the pitted 

resilial ridge, are unknown, this mytilid is assigned to 

Mytilus. M. canoasensis vidali, as represented in the 

Culebra formation, is three times as large as the nominate subspecies (Olsson, 1931, p. 41, pi. 1, fig. 12; length 

24.5 mm; Oligocene, Peru), although in Brasil it is of intermediate size (length 50 mm) and in Venezuela is comparable in size to the nominate subspecies. Larger samples, especially from Peru, may indicate that size is not 

a reliable guide for distinguishing the Oligocene and 

Miocene forms.

Occurrence: Culebra formation (early Miocene), locality 106. La Boca formation (early Miocene), localities 99f (Mytilus f sp.), 100. Lower member of Alhajuela 

formation (early Miocene), locality 79. Middle part of 

Gatun formation (middle Miocene), eastern area, locality 139g. Pirabas formation (early Miocene), Brasil. 

Middle (?) Miocene part of Santa Ines group, eastern 

Venezuela.

Genus Brachidontes Swainson 

Swainson, A treatise on malacology, p. 384,1840. 

Type (monotype) : [Modiola] sulcata [Lamarck, 1819] =

Mytilus citrinus Roding = Area modiolus Linne, living,

western Atlantic Ocean.

A small (length 10 mm), thin-shelled, incomplete 

valve from the Gatuncillo formation at locality 23b is 

listed as Brachidontes? sp.

Brachidontes species 

Plate 72, figure 7

Of medium size, height about 55 percent of length. 

Extreme anterior end missing. Umbonal swelling about 

median on anterior third of shell, closer to ventral 

margin than to dorsal margin on middle third, flattened 

on posterior third. Ventral margin slightly convex; 

posterior margin arcuate; dorsal margin defective. 

Sculptured with very narrow, very low, very closely 

spaced riblets, which are subdued near ventral margin 

near anterior end of shell. Internal features unknown.

Length (not quite complete) 27.5 mm (estimated restored length 29 mm), height 16 mm, diameter 8.5 mm 

(figured specimen).

This unnamed, evidently new, species is remarkable 

for its minute ribbing. It is represented by three valves: 

that illustrated, another of about the same size but less 

complete, and a poorly preserved, immature valve, all

from the La Boca formation. Not only is the extreme 

anterior end of the illustrated specimen missing, the 

anterior part of the umbonal ridge is pinched by 

compression.

The riblets are narrower and lower than those of 

Braohidontes mississippiensis (Conrad, 1848, p. 126, 

pi. 12, fig. 19; Mansfield, 1940, p. 176, pi. 25, fig. 40; 

Oligocene, Mississippi, Alabama), and the La Boca 

species is less elongate.

Occurrence: La Boca formation (early Miocene), 

localities 99f, 99g.

Genus Modiolus Lamarck

Lamarck, Soc. Hist. Nat. Paris Mem., p. 87, 1799.

Type (monotype and tautotype) : Mytilus modiolus Linne, living,

northern eastern and western Atlantic, and northern eastern

Pacific Oceans.

Though Volsella Scopoli, 1777, has priority, Modiolus was validated by the International Commission on 

Zoological Nomenclature in Opinion 325, published in 

1955.

The Gatuncillo formation at locality 32 yielded an 

incomplete valve listed as Modiolus? sp.

Modiolus americanus (Leach) ? 

Plate 72, figure 3

Small to moderately small, height about 60 percent 

of length. Umbo little short of anterior end of shell. 

Umbonal swelling wide and strong, decreasing in 

strength on posterior third of shell. Ventral margin 

almost straight, anterior dorsal margin straight, sloping toward anterior end of shell; posterior dorsal margin convex; posterior margin arcuate. Growth lines 

closely spaced on best preserved part of shell. Internal 

features unknown.

Length 25.6 mm, height 15 mm, diameter 10,7 mm 

(figured specimen).

Three valves one from the La Boca formation and 

two from a submerged locality on Eio Chagres at the 

former site of Las Cruces are doubtfully identified as 

Modiolus americanus (Reeve, 1858, pi. 4, fig. 15, and 

accompanying text, as Modiola tulipa Lamarck), the 

common species living off southeastern United States, 

the West Indies, and southward to northern Brasil. 

The small illustrated valve, the only complete one, and 

the larger La Boca specimen (estimated restored length 

33 mm) retain shell material. Specimens of Modiolus 

that are small or of moderate size are notoriously difficult to identify. Though the fossils have the outline of 

M. atnericanu-s, the most characteristic feature of that 

species, however, is the reddish or reddish purple coloration, or brownish rays, on the umbonal swelling and 

dorsal part of the shell. Perhaps M. waringi (Maury, 

1925, p. 93, pi. 17, fig. 1; Savaneta glauconitic sandstone
524 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

member of Springvale formation, Trinidad) is an exceptionally large form of M. americanus (length 127 

mm).

An eastern Pacific species, tentatively identified as 

M. americanus (Soot-Eyen, 1955, p. 67, pi. 6, figs. 27, 

28, text fig. 56), has been described as a new species, 

M. pseudotulipus (Olsson, 1961, p. 127, pi. 14, figs. 2, 

2a). If two species are represented, they doubtless had 

a common ancestry.

Occurrence: La Boca formation (early Miocene), locality 99f. Deposits of early Miocene age at Las Cruces, 

locality 94.

Genus Crenella Brown 

Brown, Illustrations of the conchology of Great Britain and

Ireland, pi. 31, figs. 12-14,1827.

Type (monotype) : Crenella elliptica Brown = Mytilus decussatus Montagu, living, northern eastern and western Atlantic, and northern eastern Pacific Oceans.

Crenella divaricata (d'Orbigny) 

Plate 80, figures 10, 11

Nuculocardia divaricata d'Orbigny, Mollusques, in de la Sagra, 

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

v. 2, p. 311, pi. 27, figs. 56-69, 1847(?) (living, Cuba).

Crenella divaricata (d'Orbigny), Dall, Wagner Free Inst. Sci. 

Trans., v. 3, pt. 4, p. 803, 1898 (Pliocene, Florida; living, 

North Carolina to West Indies). Weisbord, Bull. Am. 

Paleontology, v. 45, no. 204, p. 102, pi. 9, figs. 9-12, 1964 

(Pliocene, Venezuela).

fCrenella divaricata (d'Orbigny), Maury, Bull. Am. Paleontology, v. 10, no. 42, p. 95, pi. 18, fig. 13, 1925 (Miocene, 

Trinidad).

Not Crenella divaricata (d'Orbigny), Gabb, Am. Philos. Soc. 

Trans., n. ser., v. 15, p. 252, 1873 (Miocene, Dominican 

Republic) ; = C. diuturna Pilsbry and Johnson. Maury, 

Bull. Am. Paleontology, v. 5, no. 29, p. 194, pi. 26, 

fig. 18 (unrecognizable), 1917 (Miocene, Dominican Republic) ; = C. diuturna Pilsbry and Johnson.

'Small, broadly ovate, asymmetric, posterior part more 

extended than anterior. White prodissoconch distinctly 

set off by darker coloration of remainder of shell or by 

"resting stage." Sculpture subdued, riblets divaricating 

along submedian line. Faint trace of microscopic decussation. Four to six coarse teeth in anterior series (generally four or five) ; nine to 12 fine teeth in posterior 

series. Other margins of shell generally strongly 

crenulated.

Length 1.6 mm, height 2.1 mm, diameter 0.8 mm (figured specimen).

Type: Probably in British Museum (Natural 

History).

Type locality: Living, off Cuba.

This living species occurs in the lower part of the 

Gatun formation and in the middle part in the eastern 

area, but is nowhere abundant. A total of 34 specimens, 

one of which is articulated, are in the collections. The 

decussation is fainter than on most living shells 

examined.

These Gatun fossils are smaller and more narrow than 

Crenella diuturna (Pilsbry and Johnson, 1917, p. 195; 

Pilsbry, 1922, p. 414, pi. 38, fig. 7, text fig. 37); their 

decussation is less distinct, and their teeth more delicate. 

C. diuturna is abundant in the Cercado formation of 

the Dominican Eepublic. The late Miocene Trinidad 

Crenella, recorded as C. divaricata, reaches a height of 

5 mm and its decussation is relatively coarse.

Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, localities 138c, 138d, 

138e. Middle part, eastern area, localities 139b, 139c, 

139d, 147b, 152, 159d. Caloosahatchie formation (Pliocene), Florida. Playa Grande and Mare formations 

(Pliocene), Venezuela. Living, North Carolina to 

northern Brazil.

Crenella ecuadoriana santiaga Olsson 

Plate 80, figures 2, 3

Crenella ecuadoriana santiaga Olsson, Neogene mollusks from 

northwestern Ecuador, p. 33, pi. 1, fig. 13, Paleontological 

Research Inst., 1964 (Miocene, Ecuador).

Very small, narrowly ovate, almost symmetric. Prodissoconch forming a conspicuous cap or less distinctly 

set off. Sculpture generally strong, riblets divaricating 

along median line. Near ventral margin of mature shells 

one or two median riblets split into two parts. On same 

part of mature shells a thread appearing in one or two 

spaces between riblets. Three to six coarse teeth in 

anterior series (generally three); seven to nine fine teeth 

in posterior series. Other margins of shell moderately 

crenulated.

Length 2.3 mm, height 3 mm, diameter 0.6 mm (figured specimen).

Type :USNM 644250.

Type locality: Cueva de Angostura, Eio Santiago, 

Ecuador, Angostura formation.

This Crenella is a small Miocene predecessor of the 

Pliocene nominate subspecies (Pilsbry and Olsson, 1941, 

p. 55, pi. 18, figs. 2, 3; height up to 3.6 mm), which is 

still living in eastern Pacific waters (Olsson, 1961, p. 

130, pi. 17, figs. 7, 7a). The Gatun fossils are slightly 

more narrow than the type of C. ecuadoriana santiaga 

and their sculpture generally is stronger. So far as 

sculpture is concerned they closely resemble the nominate subspecies.

Contrary to the meager representation of C. divaricata, 175 specimens of C. ecuadoriana santiaga were collected, 11 of which are articulated. All, however, were 

found in the middle part of the Gatun formation in the 

western area.

Occurrence: Middle part of Gatun formation (middle 

Miocene), western area, localities 161c, 166, 169, I70a. 

Angostura formation (middle Miocene), Ecuador.
GASTROPODS, SCAPHOPODS, PELECYPODS: NTJCULIDAE TO MALLEIDAE 525

Genus Botula Morch

Morch, Catalogus conchyliorum * * * Comes de Yoldi, pt. 2, p.

55,1853. 

Type (logotype, Dall, Bartsch and Rehder, Bernice P. Bishop

Mus. Bull. 153, p. 59, 1938) : Mytilus fuscus Gmelin, living.

western Atlantic and eastern Pacific Oceans.

The type designation was discussed by Iredale (1939, 

p. 415), who designated the species designated by Dall, 

Bartsch, and Rehder a year earlier.

Botula fusca (Gmelin) ?

Small, elongate, subcylindrical, umbo terminal. 

Anterior margin subtruncated; dorsal margin slightly 

convex; posterior margin arcuate; ventral margin almost straight. Posterior part of shell marked by finely 

engraved, closely spaced growth lines. Internal features 

unknown.

Length 13 mm, height 5.5 mm, diameter (both valves) 

6.3 mm.

An articulated specimen from the La Boca formation is doubtfully identified as Botula fusca (SootRyen, 1955, p. 86, pi. 9, fig. 52, text figs. TO-T2; Warmke 

and Abbott, 1961, p. 163, pi. 31, fig. 9). The fossil is 

badly cracked and will not stand much handling; 

in fact, several patches of shell peeled off during 

examination.

Most shells of B. fusca, formerly designated B. cinnamomea (Lamarck), have a low swelling extending 

from the umbo to the ventral margin, an insinuation of 

the margin behind the swelling, and irregularly spaced 

and strongly marked "resting stages." The species has 

an age range of early Miocene to the present time and is 

living in both western Atlantic and eastern Pacific 

waters. B. hispaniolae (Maury, 1917, p. 193, pi. 35, fig. 

11; Miocene, Dominican Republic) is a typical representative.

Occurrence: La Boca formation (early Miocene), 

locality 116a.

Family PINNIDAE 

Genus Atrina Gray

Gray, Synopsis of the contents of the British Museum, 44th ed., 

Mollusks, p. 83, 1842 (genus without species).

Type (monotype. Gray, Zool. Soc. London Proc., p. 199, 1847) : 

P[inna] nigra [Chemnitz] [Dillwyn] =Pinna vexillum 

Born, living, western Pacific Ocean.

Internal molds from the upper member of the Alhajuela formation are listed as Atrina? sp.

Subgenus?

Atrina species

Plate, 69, figure 20

Small, broadly wedge-shaped, moderately inflated. 

Dorsal margin straight; ventral margin slightly convex. Dorsal and median parts sculptured with six wide

ribs, wider than space between them, except near dorsal 

margin. Ventral part sculptured with wide concentric 

swellings, wider than space between them. Internal 

features unknown.

Length (incomplete) 33 mm (estimated length by 

projecting missing anterior part 45 mm), height 26 mm, 

diameter 9 mm (figured specimen).

This coarsely sculptured species, found in the Rio 

Frijol area of the Gatuncillo formation, is represented 

by a gaping articulated internal mold, the right part 

of which is in better condition than the left. An unknown 

length of the posterior part presumably is missing. This 

species evidently is new.

Occurrence: Gatuncillo formation (late Eocene), 

locality 32.

Subgenus Servatrina Iredale

Iredale, Great Barrier Reef expedition, 1928-29, Scientific Reports, v. 5, no. 6, Mollusca, pt. 1, p. 317, British Museum 

(Natural History) 1939.

Type (orthotype) : Pinna assimilis Reeve, living, western Pacific 

Ocean.

Atrina (Servatrina) aff. A. serrata (Sowerby) 

Plate 82, figures 9-11

fAtrina sp., Woodring, Carnegie Inst. Washington Pub. 366, 

p. 57, pi. 6, fig. 9, 1925 (Miocene, Jamaica).

f Atrina sp., Jung, Bull. Am. Paleontology, v. 49, no. 223, p. 439, 

1965 (Miocene, Venezuela).

f Atrina sp., Jung, Bull. Am. Paleontology, v. 55, no. 247, p. 342, 

1969 (Miocene, Trinidad).

Moderately large (estimated length at least 125 mm), 

wedge-shaped so far as known, moderately inflated, thinshelled. Dorsal margin straight; ventral margin slightly 

concave near anterior end, convex farther from anterior 

end. Dorsal and median parts sculptured with narrow, 

closely spaced ribs. Ventral part sculptured with concentric swellings. Swellings smooth or inner nacreous 

layer bearing small, narrow, rectangular pustules, alined 

parallel to ribs, corresponding calcite layer generally 

missing. Nacreous layer extending to broken posterior 

end of specimen having highest posterior end (height 

something more than 40 mm).

Length (incomplete) 64.5 mm, height 25 mm, diameter about 5 mm (larger figured specimen).

This pinnid occurs in the lower and middle parts of 

the Gatun formation and in the Chagres sandstone. All 

of the 19 specimens are incomplete, especially at the 

posterior end, as usual with fossil pinnids; a few are 

almost complete at the anterior end. Much, or all, of the 

thin calcite layer is missing, revealing the equally thin 

nacreous layer. The most satisfactory specimens were 

found at locality 139g, in the middle part of the Gatun, 

where 14 were collected, five of which are small fragments. By projecting the missing anterior part of the
526 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

highest specimen, mentioned in the description, a length 

of about 100 mm is indicated. Inasmuch as the nacreous 

layer extends about two-thirds to three-fourths of the 

length of the shell (Turner and Rosewater, 1958, p. 

310), a total length of at least about 125 mm is estimated, 

even if the nacreous layer extends no farther than the 

broken posterior end. Only a few specimens, two of 

which are illustrated (pi. 82, figs, 10,11), show pustules 

on the ventral part of the shell.

These fossils are interpreted to represent a pinnid 

allied to the living western Atlantic Atrina serrata 

(Sowerby) (Turner and Eosewater, 1958, p. 320, pis. 

170, 171). The typical form of that species is sculptured with many narrow ribs bearing closely spaced 

vaulted scales. The sculpture, however, is not uniform. 

The early part of a pair of valves from Port-au-Prince, 

Haiti (TJSNM 347210), for example, is sculptured much 

like the Panama fossils, and low scales do not appear 

until a late stage. The sculpture of other Miocene forms 

resembles that of the Panama species: A. harrisi (Dall, 

1890-1903, p. 663, pi. 29, fig. 11,1898; Choptank formation, Maryland; the type is in poor condition, but better specimens are now available, for example, a topotype, USNM 646825) ; specimens from the Oak Grove 

sand member of the Shoal River formation of Florida, 

identified by Dall as A. chipolana (Dall, 1890-1903, 

p. 662,1898), though the type material, from the Chipola 

formation, is unidentifiable; and specimens of late Miocene of Pliocene age from Florida (USNM 646824) 

that show pustules like those on the two Gatun fragments. Though the diagnostic feature of Servatrina 

the location of the posterior adductor scar, well within 

the posterior border of the nacreous layer is not observable on any of these fossils, they are assigned to that 

subgenus, as it is unlikely that the external features 

belie the affinities.

The doubtfully identified fossils from Jamaica, Venezuela, and Trinidad are small fragments.

Occurrence: Lower and middle parts of Gatun formation (middle Miocene). Lower part, locality 136a. 

Middle part, eastern area, locality 139g; western area, 

localities 166, 169. Chagres sandstone (late Miocene), 

localities 206 206b (Atrina? sp.). Identification doubtful: Bowden formation (middle Miocene), Jamaica; 

Cantaure formation (middle Miocene), Venezuela; 

Melajo clay member of Springvale formation (late Miocene) , Trinidad.

Family PTERIIDAE

Genus Pteria Scopoli

Scopoli, Introductio ad Mstoriam naturalem, p. 397, 1777. 

Type (monotype) : Mytilu# Mrundo Linn6, living, eastern Atlantic Ocean and Mediterranean Sea.

Pteria inornata (Gabb) ? 

Plate 73, figure 9, plate 80, figures 4, 5

Small, moderately inflated. Anterior auricle subtriangular, swollen, set off by groove. Length of posterior 

auricle unknown.

Length (incomplete) 28 mm, height 24 mm, diameter 

about 6 mm (largest figured specimen).

Unsatisfactory material from the La Boca and Gatun 

formations is doubtfully identified as Pteria inornata 

(Pilsbry, 1922, p. 408, pi. 43, figs. 6,7; Miocene, Dominican Republic). Almost all of these fossils are parts of 

left valves or molds of incomplete left valves. Five were 

recovered from the La Boca and some 30 from the 

Gatun, but most of the Gatun fossils are small shell 

fragments.

The type of P. inornata, shown in Pilsbry's figure 6, 

is in poor condition. As remarked by Pilsbry, the small 

mold illustrated in his figure 7 shows the outline. Fragments of small valves, smaller than the type, are abundant in the Cercado formation on Rio Mao at USGS 

locality 8525 (Maury's bluff 3). The species has been 

recognized in the Bowden formation of Jamaica (Woodring, 1925, p. 58, pi. 6, fig. 11), the middle Miocene deposits of southeastern Costa Rica (Olsson, 1922, p. 195, 

pi. 28, fig. 9), and possibly in the late Oligocene San 

Sebastian formation of Puerto Rico (Maury, 1920, p. 

13).

The perfect preservation of the moderately large Oligocene species, P. argentea (Conrad) (1848, p. 126, pi. 

12, fig. 10), as represented in the Mint Spring marl 

member of the Marianna limestone, stands in marked 

contrast to the wretched condition of many of the 

American Tertiary species.

Occurrence: La Boca formation (early Miocene), localities 99h, 114,115a. Lower and middle parts of Gatun 

formation (middle Miocene). Lower part, localities 138, 

138c, 138d. Middle part, eastern area, localities 139b, 

139c, 139e, 139g, 147g, 155,159d.

Family ISOGNOMONIDAE 

Genus Isognomon [Lightfoot]

Ligthtfoot, anonymous in Catalogue of the Portland Museum, 

p. 9, 1786.

Type (tautotype) : Ostrea isognomon [isognomum] Linne, living, 

western Pacific Ocean. "176, Ostrea, isognomon L., called 

Isognoma, llgnea by S[olander]". For the usage of Isognoma 

and Isognomon in the Portland Catalogue see Render (1967, 

p. 6), but for item 3041 in that account substitute 1242. 

The gender of Isognomon is masculine.

Subgenus Mimonion Woodring, n. subgen.

Type: Isognomon (Mimonion) mimeticus Woodring, n. sp., Miocene, Canal Zone.

Of medium size, narrowly mytiliform, barely and 

broadly inflated, moderately thick-shelled. Anterior
GASTROPODS, SCAPHOPODS, PELECYPODS: NUCULIDAE TO MALLEIDAE 527

margin slightly concave, apex of shallow concavity near 

dorsal third of height; dorsal and posterior margins 

forming broad arc; ventral margin narrowly arcuate. 

Ventral and posterior surface bearing very low, irregularly spaced undulations. Eight wide ligament grooves 

about as wide as space between them. Shell margin bent 

inward at site of byssus. Muscle scar close to posterior 

margin of shell, elongate, upper end hook-shaped, but 

not bent.

The type is a remarkable, narrowly mytiliform species. The outline is strikingly different from that of the 

hammer-shaped type of Isognomon s.s. It differs also 

from the subovate outline of Melina, cited under the 

next subgeneric heading. Mimonion is much more narrowly mytiliform than the Jurassic subgenus Mytiloperna (von Ihering, 1903, p. 123; type (monotype) : 

MytUoperna americana (Forbes) (Pema americana 

Forbes), Jurassic, Chile), the type of which is an enormous species (height 295 mm). Small European species 

also are more broadly mytiliform.

Isognomon (Mimonion) mimeticus Woodring, n. sp. 

Plate 71, figures 19, 20

Features of the subgenus, which is monotypic.

Height 49 mm, width 25 mm, diameter 6.5 mm (type).

Type :USNM 646893.

Type locality: 116a (USGS 20956, East bank of 

Panama Canal at Canal station 1870, near Paraiso, 

Canal Zone), La Boca formation.

Isognomon mimeticus is represented by the type (a 

complete, but badly cracked, right valve) and three 

fragments. As the type will not stand much pressure, 

thorough cleaning, including dislodging the pebble on 

the interior, was not attempted.

The exterior mimics specimens of intermediate size 

of Mytilus canoasensis vidali, such as that shown on 

plate 73, figure 1. It can be seen, however, that /. 

mimeticus lacks a swollen umbonal ridge, the apex of the 

concavity of the anterior margin (designated ventral 

for Mytilus) is farther toward the umbo, and part of 

the surface is weakly undulated.

Occurrence: La Boca formation (early Miocene), 

locality 116a.

Subgenus Melina Betzius?

Retzius,, Dissertatio historico-naturalis nova testaceorum genera, p. 22,1788.

Type (logotype, Herrmannsen, Indicis generum malacozoorum, 

v. 2, p. 37, 1847) : Ostrea ephippium Linne, living, western 

Pacific Ocean.

Isognomon (Melina?) species 

Plate 80, figure 1

I'Isognomon sp., Woodring, Carnegie Inst. Washington Pub. 366, 

p. 58, pi. 6, fig. 10,1925 (Miocene, Jamaica).

Presumably moderately large, at least dorsal part 

thick-shelled, outline unknown. Thirteen ligament 

grooves (three modified by deformity caused by boring 

organism) slightly wider than space between them. 

Byssal groove moderately wide, moderately deep.

Height (incomplete) 29 mm, width (incomplete) 37.5 

mm, thickness of shell in dorsal area 6.8 mm.

The middle part of the Gatun formation at locality 

170 yielded two fragments of Isognomon: the illustrated 

thick-shelled dorsal fragment of a right valve and a 

thin-shelled fragment of another right valve, the ligament area of which is missing.

The illustrated specimen is more thick-shelled than 

any species of the genus living in American waters. Perhaps it is the unnamed species represented at Bowden, 

Jamaica, by a thick-shelled dorsal fragment of a left 

valve that retains only the anteriormost three ligament 

grooves. The byssal groove of that fragment, however, 

is wide and deep. Though the outline of the immature 

left valve from Bowden (height 7 mm) was described as 

subquadrate, the posterior margin defective and therefore the outline is questionable. Three of the four ligament grooves are remarkably wide.

Occurrence: Middle part of Gatun formation (middle 

Miocene), western area, locality 170. Bowden formation 

(middle Miocene), Jamaica (identification doubtful).

Family MALLEIDAE 

Genus Exputens Clark

Clark, Jour. Paleontology, v. 8, p. 270,1934.

Type (logotype, H. E. Vokes, New York Acad. Sci. Annals, v. 38, 

p. 51,1939) : Exputens llajasensis Clark, Eocene, California.

Though Clark doubtless intended Exputens llajasensis to be the type, he did not so designate it. The other 

species described by Clark, E. alexi, evidently is a small 

form of E. llajasensis.

This Eocene genus is recorded from the middle 

Eocene of California and the middle Eocene of the 

Ukraine (Zelinska, 1963, p. 104, pi. 1, figs. 9, 9a, as 

Vulsella longicauda (Archiac) ; Ostrea longicauda 

Archiac, 1850, p. 439, pi. 13, fig. 3, however, is not a 

species of Exputens), and the late Eocene of Florida: 

Vulsella ocalensis MacNeil, 1934, p. 431, figs. 5-11; assigned to Exputens by Palmer, in Palmer and Brann, 

(1965, p. 143). My colleague Druid Wilson has 

recognized the genus in the late Eocene of Georgia 

(USGS 7126, 7127, 7121), and in the middle Eocene 

(USGS 7832) and middle or late Eocene (USGS 22369) 

of North Carolina. Mr. Wilson also offered advice concerning the age of the occurrences in the southeastern 

states and called my attention to the Russian publication.
528 GEOLOGY AND PALEONTOLOGY OF CANAL ZONE

Exputens bostrychodes Woodring, n. sp. 

Plate 68, figures 7, 13, 17, 18

Of medium size, short, height almost equal to length, 

equilateral or apparently almost equilateral. Anterior 

and posterior margins arcuate. Wide swollen ridge extending obliquely downward from umbo. Posterior part 

compressed. Tip of umbo coiled. Conspicuous concave 

auricle extending outward and upward from posterior 

side of umbo. Ligament groove deep, triangular, curving posteriorly from tip of umbo, sharply limited on 

anterior side. Surface marked by irregularly spaced and 

irregularly exaggerated growth lines, most conspicuous 

on umbonal ridge and anterior part of shell.

Length 23.7 nun, height 20.4 mm, diameter (both 

valves) 13 mm (type). Length (incomplete) 30 mm 

(estimated restored length 35 mm), height 26.2 mm, 

diameter (both valves) 14.6mm (paratype).

Type: USNM 646890; paratype USNM 646891.

Type locality: 12 (USGS 17162, Madden basin, 

Panama, lumber road south of Kio Puente, 4 km east of 

Casada Larga), Gatuncillo formation.

In many respects Exputens bostrychodes is a remarkable species. Other species are auriculate, but their 

auricle is not so large in proportion to the size of the 

shell; the ligament groove of other species is shallower 

and not curved; no other species is so short, high, and 

equilateral.

The type and paratype are articulated, but the valves 

of both are slightly rotated. The posterior part of the 

ligament groove of the right valve of the paratype is 

shallow. It evidently is malformed; perhaps the missing 

auricle of that valve was broken off during life. Unlike 

the other mollusks from the marly limestone at the type 

locality, the shell material of these two specimens is 

preserved, although the outer calcite layer is missing in 

small patches. A poorly preserved right valve was collected from sandstone at locality 32.

Occurrence: Gatuncillo formation (late Eocene), 

localities 12,32.

REFERENCES CITED

Adams, Henry, and Adams, Arthur, 1853-58, The genera of Recent Mollusca, v. 2, 660 pv London.

Aldrich, T. H., 1897, Notes on Eocene Mollusca, with descriptions 

of some new species: Bull. Am. Paleontology, v. 2, no. 8, 26 

p., 5 pis.

Altena, C. O. van Regteren, 1968, Yoldia perprotracta Ball, a 

synonym of Leda neivcombi Angas: Basteria, v. 32, p. 3.

Anderson, F. M., 1928, Notes on lower Tertiary deposits of 

Colombia and their molluscan and foraminiferal fauna: 

California Acad. Sci. Proc., 4th ser., v. 17, no. 1, p. 1-28, pi. 1.

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3 figs.

Zelinska, V. O., 1963, Mollusks of middle Eocene strata in 

Pobuzhzhe district: Geologichnye Zhur., v. 23, no. 4, p. 99- 

105,1 pi. (inRussian).

INDEX

[Italic page numbers indicate major references and descriptions]

Page 

abrupta, Turritella............................ 468

acanthodes, Tympanotonos_____.___. _ 454,

455, 471-472, 473, pis. 68, 69 

acapulcensis, Saccetta........................ 492

Acar.......................................... 497

domingensis.....A50, 462, 434, 497-498, pi. 77

domingensisf............................ 458,460

gradata................................... 498

acares, Leptomurex.......... 454, 455, 476-477, pi. 68

Acila......................................... 489

s.s........................................ 489

isthmica burica............................ 490

sp...................................... 457,489

(Acila) isthmica........................... 489

isthmica isthmica...................... 456,

458,460,462,464,465,489-490, pis. 70, 71, 

76,82

Acknowledgments_______________ 454 

acrita, Saccetta.............................. 492,493

epacra, Saccetta...... 462,464, 492-49S, 494, pi. 75

Acteonacea__________________ 481 

Acteonellinae? ______________ __ 481 

Acteonidae.__________________ 481 

actinophora, Anadara........................ 503

Area,...................................... 502

(Scapharca)........................... 502

Scapharca (Scapharca).................... 502

actinophora, Anadara (Rasia)............. 462,

464, 502-503, pi. 76 

acuminata, Leda.............................. 494

Nucufa [Leda}....^........................ 494

acus, Cadulus................................. 487

acuta, Saccella.......................... 455,491,492

acuticostata, Glycymeris....................... 520

adiaphora, Anadara (Rasia) honensis. A65, 502, pi. 82 

Adrana....................................... 494

crenifera............................ 458,465,494

newcambi................................. 495

cf. A. newcmibi..................... 462,494-495

perprotracta............................... 495

stena..................... 455,456,465, 494, p. 70

fp.......................... 457,458,462,494,495

aguadittensis, Orthaulax....................... 511

aipeia, Jupiteria................ 456, 490-491, pi. 72

Akleistostama................................. 475

albicomatus, fCadulus (Gadilla) afl.._____ 486 

albolineata, Pectunculus (Axinaea) gatunensis 

n.f., afl. Axinaea....--...-._...._....... 519

aldrichi, Volvariella............................ 481

alexi,Exputens............................... 527

Alhajuela formation....__.__..__._ 460-461

aUa,Noetiamacdonaldi ..................... 518,519

alternata, Barbatia............................ 497

Byssoarca................................ 497

americana, Mytiloperna...................... 527

Perna.................................... 527

americanus, Modiolus................... 460, 523, 524

americanusf, Modiolus..... ...458, 460, 62S-524, pi. 72

Page

Anadara. .............................. 461,464,498

s.s._. .--....._.__.._______._________... 498

actinophora.. .......... . ............ . ..... 503

arthurpenneltt. ........................... 506

auriculata. ............................ ... 504

berjadinensis ... ...... . ................. ... 516

boggsi.. ..... . ..... . .................. ..... 516

cf.^4. chavezi. ............................. 514

sp. afl. A. chiriquiensis bolivari. ........... 509

cibaoica ... . ............... . ......... ...... 499

concinna.... ..... . .................... 465, 501

corcupidonis. ............................. 515

cumanensis.. .......................... ... 514

donacia.. .. _______________ 499 

emarginara... .......... . ................ 465, 504

afl. A.filicata.. ........................... 514

floridana. .............................. 503, 504

garitensis. .................... ....... ----- 509

granosa .... ...... ............... . ... . ..... 499

guajatica... .................. ... .......... 499

hindsi. ................................... 515

honensis .............................. .... 502

honensis.. ............................ 465

hopkinsi.. ................................ 507

hyphalopUema. ......................... 461, 507

inaeguilateralis ...... ...................... 501

istmica.. ................................. 503

tarkinti.. ................................. 508

Henosalienosa.. ....... .. ........... . .... . 503

secticostata ______ __________ .. 503, 504

margaretae..... ... ..... .... ... ............ 502

marksi.. ....... ... .... ... . ... -... ... .... .. 503

medioamericana ......... . ......... . ... .. 460, 502

meroensis.--- .... ... ..... ... ....... ... .... 505

micotera. ................... . ......... . ... 506

mississippiensis ... . ....... . ... .... ...... 453, 504

notabilis.. ................................ 504

nux. ............................ . ....... . 514

pennelli. ....... .......................... 506

perplura ......... .. .............. . ..... ... 506

pittieri. . ............................... 515

santarosanageraetera....... ... ... ...... 460, 507

singewaldi. ............................... 506

doma. .... . .... .... ....... .. .... ...... 506

spiekeri ............................ ....... 506

cLA.spiekeri.. ........ ........... ..... 506

subcrenata.. ....... ... ..... .... ...... .... . 499

sulcicosta ..... . ........ .... .............. . 499

tectumcolumbae.. ....................... 461,507

tolepia....... ............................. 506

transversa ............. . ... . ............... 505

veatchi matarucana .... ... ................. 508

zapatolensis ........................... .... 506

zorritosensis ........................ ....... 511

zuliana ... ................................ 506

maracaibensis. .... .................... 506

sp......... ......................... 457,501,515

(Anadara) carmenensis ....... ... .......... 500

I 'Anadara (Anadara) istmica.. ____ - 503 

Anadara (Argina) campechmsis . ____ ----- 516

(Cunearca) eumeces.. ..... .... ... .... 462,516, pi.

? Anadara (Cunearca) sp. ------------------- 577

Page

Anadara (Grandiarca) balboai. 457,458,460, 510, pi. 72 

(Grandiarca) chiriquiensis........... 508,509,510

chiriquiensis chiriquiensis.............. 456,

457,460. £08-5*0, pi. 72 

dolaticosta ....... 462,464, 610 611, 513,pi.80

grandis............................. 464,508

colombiensis...................... 511,512

grandis....................... 511,512,513

patricia....................... 511,512,513

patricia?........... 462,464, 512-51S, pi.79

waringi............................. 511,512

n. sp................... . 511,512

(Hawaiarcaf) sp. .- - - 456,457,499 

(Larkinia) grandis........................ 512

patricia............................... 512

waringi............................... 512

(Potiarca) cf. A. berjadinensis.... 462,516, pi. 77

chavezi................................ 460,

461,462,464, 514 515, 516, pis. 81,82 

afl. A. chavezi............. 458,460, 614, Pi- 72

chemnitzii........................... 514,515

sp.................................. 465,514

(Rasia) actinophora actinophora........... 462,

464,502-508, pi. 76 

athroa................ 457,458,460,505,pi. 72

athroaf............................... 457

carmenensis................... 455,500,pl. 70

dariensis dariensis..... . 547,

460,461,462,464,465, 501-602, pi. 77 

dariensisf........................... 461

progonica........................... 456,

457,458,460,500, pi. 71 

cf. A. emarginata...................... 462,

465,504, pi. 77 

fissicosta.............................. 461,

462-464, 505-606, pi. 78 

cf. A. fissicosta...................... 461,506

honensis adiaphora............ 465,502,pi. 82

lienosatrochala.......... ...... . 462,

464,508-504, pi. 76 

lita................. 455, 456, 504-505, pi. 70

cf. A. medioamericana........... 458,460, 502

sechurana........... 462, 464, 505, 506, pi. 79

sp ........... . 455,465,504

(Scapharca) dariensis. _____ ...--- 501

(Tosarca) campta....... 458, 460, 506-507, pi. 73

cf. A. tectumcolumbae....... 461, 507, pi. 73

tosaensis..........-------------------- 506

veatchi...................... .. 461,507

ve&tchi............ 462, 464, 507-508, pi. 78

sp..-.---. - - 462,508

Anadarinae_------------ ------ - 4&8

anguillana, Area .............---------------- 509

annulatus, Cadulus........ - 487

anomalus, Triton.....--- ... - - - ------ 478

Antalis. ..................... . - 485

antiquata, Area......................-....-- 498,500

antyx, Hannatoma.......... 454, 455, 470-471, pi. 68

aperta, Calyptraea.............--------------- 473

Calyptraea cf. C....................... 474

f Calyptraea ct. C. ----------------------- 473

533
534 INDEX

Page

Area......................................... 495

actinophora............................... 502

anguulana................................ 509

antiquata............................... 498,500

aviculaeformis............................. 499

avicularoides.............................. 499

aviculoides............................_ ... 499

balboai.................................... 510

barbata...............................__ 496

brasiliana................................. 516

chiriquiensis.............................. 508

websteri............................... 599

tArea cf. consobrina........................... 501

Area datti..................................... 510

dariensis.................................. 501

dUuvii.................................... 500

dolaticosta................................. 510

domingensis....... .........___........ 497

floridana.................................. 500

formosa................................... 499

fragttis.................................... 491

gatunensis................................ 501

glycymeris................................ 519

grandis......................... 508,511,512,513

waringi............................... 512

imbricata............. 461,462, 464, 496, pis. 73, 77

inaeguivalvis.............................. 498

incongrua................................. 516

invalida................................... 510

larkinii................................... 508

lesueuri................................... 504

ttmanica.................................. 514

macdonaldi................................ 518

subreversa............................. 518

mississippiensis........................... 505

modiolus.................................. 523

noae...................................... 495

nucleus................................... 488

obesiformis................................ 509

ovalis..................................... 516

patriarcha................................. 513

Patricia............................. 464,512,513

pennelli................................... 513

perfaceta.................................. 514

pexata.................................... 516

pilula..................................... 513

pomponiana.............................. 514

reversa.................................... 517

senttis.................................... 508

fArca septifera................................ 509

Ana umbonata................................ 496

umbonata paezensis....................... 496

Veatchi................................... 507

websterL.................................. 509

fArca (Anadara) dUuvii....................... 501

Area (Anadara) nelsoni....................... 509

(Anadara) sellardsi........................ 508

fArca (Anadara) septifera..................... 509

Area (Anadara) toroensis...................... 509

(Anadara) toroensis crassa................. 509

toroensis prolata....................... 509

usiacurii............................ 511,512

(Area) imbricata.......................... 496

umbonata............................. 496

morantensis......................... 496

(Argina) samanensis...................... 517

(Dttuvarca) dariensis...................... 501

sechurana............................. 505

(Macrodon) dalli.......................... 510

(Noetia) macdonaldi....................... 518

(Scapharca) actinophora................... 502

charanensis........................... 518

chavezi................................ 514

chiriquiensis.......................... 508

crescens............................... 509

dariensis.............................. 501

fissicosta.............................. 505

imporcata..---........................ 509

obesiformis............................ 509

veatchi................................ 507

Page 

Area Continued

(Scapharcaf) veatchi....................... 507

(Senilia) chiriquiensis bolivari............. 509

chiriquiensis obesiformis............... 509

fArca (Senilia) chitiquiensis septifera.......... 509

Area (Senilia) chiriquiensis toroensis........... 509

Architectonica................................. 473

s.s ....___.._._...........__.. 473

nobilisnobilis........................... 460,473

(Architectonica) cf. A. nobilis...... 458, 460, 473

nobilis karsteni........................ 473

subsp................ 458, 460, 473, pi. 71

Architectonicidae...................._..... 473

Arcidae..__................._._._.-.- 495

Arcinae........_..............._..__- 495

arctata, Glycymeris.......................... 521,522

arctica, Nucula............................... 495

argentea, Pteria............................... 526

Arginella.-.................................... 517

samanensis............................... 517

armillatum, Dentalium......................... 482

armittatum, Dentalium (Dentalium)....... 456,

462, 482, pi. 75 

proterum, Dentalium (D entalium)......... 456,

464, 482, pi. 71 

arthurpennelli, Anadara.. ----------------__ 506

assimilis, Pinna.............................. 525

ater, Faunus........................... 455, 469, 470

Strombus................................. 469

athroa, Anadara (Rasia).....-..-.-.....-----. 457,

458, 460, 505, pi. 72 

athroaf, Anadara (Rasia)..................... 457

Atrina........................................ 525

chipolana................................. 526

harrisi.................................... 526

serrata................................. 465, 526

sp............. ..-- 454, 525, pi. 69

Atrinafsp............................. 461,525,526

fAtrina sp...---.__._.__----- . 525

Atrina (Servatrina) aflf. A. serrata............. 462,

465, 6&S-5&6, pi. 82 

auriculata, Anadara........................... 504

auriculatum, Crucibulum..................... 474

aviculaeformis, Area........................... 499

avicularoides, Area............................ 499

aviculoides, Area.................-------...... 499

Bailya........................................ $8

crossata.................... 461, 462, 478, pi. 77

balboae, Anadara (Grandmrca)................ 457,

458, 460, 610, pi. 72 

Leda.---.------.. --.- - - 493

Saccella... 457, 480, 462, 464, 465, 493-494, pi. 77 

aff. S.........- .-... 457, 458, 460, 493

Scapharca (Scapharca)-------------- --- 510

balboai,Area..............---------------- 510

barbata, Area................................. 496

Barbatia................................ 490,499,500

s.s . . .- -. - - 496 

alternate....................- . - ---- 497

cancellaria ........................... 456,496

Candida.....................--------...... 496

divaricata-................................ 497

Barbatia? sv ....................... .-- 496

Barbatia (Acar) domingensis................... 497

f Barbatia (Acar) sp. cf. B. (Acar) domingensis. 497 

Barbatia (Acar) reticulata........-.......--- 497

(Barbatia) cf. B. cancellaria....- 456,458,480,496

(Cattoarca) taeniata....................... 497

(CucuUaria) taeniata................. ----- 497

(Diluvarca) opthanta--...........--------- 514

Bayania................................ 455,408,469

bezanconi..... ----------------------- 469

epelys..................... 454,455, 468-469, pi. 68

lactea............................... 455,468,469

secalis. ... .......... ----- - 469

semidecussata............................. 469

f Bayania sp...-------------------- - ---- 468

Page 

herjadinensis, Anadara........................ 516

Anadara (Potiarca) cf. A......... 462, 516,pi. 77

bezanconi, Bayania............................ 469

Bezanconia................................. 455, 472

cosmeta.- ............454, 455, 479-478, pi. 68

pupoidea.. .............................. 472

spirata..----.-.......................... 455,473

woodsi....-.--.-....----... ... ..... - 473

boggsi, Anadara---............................. 516

Bohio formation.-.-....-...-....-...-....-- 455-456

Bohio(?) formation, marine member......--.. 455

bolivari, Anadara sp. aff. A. chiriquiensis....... 509

Area (Senilia) chiriquiensis................ 509

Scapharca chiriquiensis-...............-... 509

bostrychodes, Exputens............ 454,455, 628, pi. 68

bothrum,Dentalium (Dentalium).. 462, 482-488, pi. 75 

Botula........................................ 525

cinnamomea.............................. 525

fusca ..-......................... 460,484,525

fuscaf.............................. 458,480,505

hispaniolae................................ 525

Brachidontes---.............................. 523

mississippiensis......................... 460,523

sp...... ... ......---- 458, 460, 523, pi. 72

Brachidontesfsp............................ 454,523

brasiliana, Area............................... 516

bravoensis, Pseudofaunus...................... 469

brocchii, Jupiteria.....---------------------- 456,491

Buccinidae.--- ___--.----. ... 477

Bulla gibbosa................................. 475

burica,AcUa isthmica.......................... 490

bushii, Cadulus carolinensis.------------------ 487

Cadulus (Platyschides)....--..--....... . 462,

464, 487-488, pi. 75 

Byssoarca alternata........ ............. 497

divaricata......... ..................... 497

,...--.-- ---.- 505

cachla, Cattoarca (Taeniarca)...... 462,464, 497, pi. 77

Cadulus.....-..------------------------- -- 486

acus......................---------....... 487

annulatus................................ 487

carolinensis bushii......................... 487

(carolinensis var. ?) bushii......... ....... 487

dentalinus................................ 486

elegantissimus............................ 486

grandis.........................-......... 487

hendersoni.. ............................ 487

panamensis.................. ----- -- 487

perpusillus. ................- --- 487

sp....----------.----------------------- 455,^86

f Cadulus (Gadtta) aff. albicomatus............. 486

Cadulus (Gadila) spiniformis.................. 487

( GadUopsis) dentalinus........ --. ....... 462,

464, 486-487, 488, pi. 75 

dolichus.................... 455, 486, pi. 70

sp - 455,486

(Platyschides) bushii...... 462,464,487-488, pi. 75

epetrion ...................... 462,487, pi. 75

cahuitensis, Nucula--....................... 488,490

Nucula (Nucula) cf. N........ 462,465,488, pi. 75

Caimi to formation.._. ..........--.----- 456

Calloarca.... 4&

8.8... - 497

leonensis...........----------------------- 497

phalacra....................-- ---------- 497

taeniata -...... 497

(Taeniarca) cachla........... 462,464,497, pi. 77

Calyptraea...... --------------------- ------ 473

aperta....................----------- 473

cf. C. aperta.................------- - - 474

f Calyptraea cf. C. aperta- -..---------------- 47a

Calyptraea centralis.----------------------- 474

labellata--- . 474

laevigata...... - --------------------- 473

lispa..... 454,473-474, pi. 69

spinosa..... -. ---------------- ----- 474
INDEX 535

Page

Calyptraeidae__________..._____ 473 

campechensis, Anadara (Argina).............. 516

campta, Anadara (Tosarca).A5S, 460, 506-507, pi. 73 

camptica, Harrisianella..... .454, 455, 472, pi. 69

canalis, Glycymeris..................____ 520,521

fGlycymeris............................... 520

Glycymeris (Tucetona) pectinata.......... 460,

461,462,464, 520-521, pi. 81

canalis? Glycymeris (Tucetona) pectinata. 458,460,461 

canalis colombiensis, Glycymeris. ____. _. 521

democraciana, Glycymeris..... .._-...__ 522

var., Glycymeris.. ____...._........ 522

Cancellaria. _____________.___ 431

s.s........................................ 481

lipara...............................__. 481

(Cancellaria) epistomifera lipara.......... 481

epistomifera gathra........................ 481

Cancellaria, Barbatia...................... 456, 496

Barbatia (Barbatia') cf. B........456,458,460,456

Cancellariidae____.__....__.__... 481

Candida, Barbatia............................. 496

canoasensis vidali, Mytilus.................... 456,

457, 458,460, 461,462, 464, 522-523, 527, 

pi. 73----------------------

canonica, Saccella.. ____.....____._ 493

Cara......................................... 499

caracolt, Glycymeris......................... 455,519

Glycymeris (Glycymeris) cf. G. 454,455,5/9, pi. 69 

carbasina, Glycymeris......................... 519

Glycymeris (Glycymeris).................. 458,

460,462,464,5/9-520, pis. 79, 81 

carbasina? Glycymeris......................... 519

carmenensis, Anadara (Anadara).............. 500

Anadara (Rasia)................ 455, 500, pi. 70

carolinensis bushii, Cadulus................... 487

Cypraea.................. .._______ 475

Cassididae___________________ 476 

cedralensis, Scapharca grandis................. 512

centralis, Calyptraea.......................... 474

cerinum, Dentalium................... ........ 484

Cerithiidae_.___........._............ 470

Cerithlinae________.....__....... 472

Cerithium hillsboroensis.... _.. ___ _ __ 471

spiratum.................................. 472

Chagres sandstone, Including Toro limestone

member._...__.__......... 465

Change in age assignment...._..--.-._.. 454

Charadreon........... ..........___. 454,455 469

leptus........ ............ 454, 469, 471, pi. 68

charanensis,Arca (Scapharca)................. 518

chavezi, Anadara, cf.A...... .....__........ 514

Anadara (Potiarca)....................... 460,

461,462,464,5/4-5/5,516, pis. 81,82 

(Potiarca) afl. A.... 458,460,5/4, pi. 72

Area (Scapharca)......................... 514

chemnitzii, Anadara (Potiarca).............. 514,515

chipolana.Atrina.-.....__.................... 526

chiriquiensis, Anadara (Grandiarca).. 508,609,510

Area......... .................______ 508

(Scapharca)........................... 508

Scapharca..... ....__._______.... 508

(Scapharca)..............._____. 508

bolivari, Anadara sp. afl. A....__...._. 509

Area (Senilia)........................ 509

Scapharca................... ......... 509

chiriquiensis, Anadara (Grandiarca)-....... 456,

457,460, 508-5/0, pi. 72

obesiformis,Arca (Senilia)................. 509

septifera, ?Arca (Senilia).................. 509

toroensis, Area (Senilia)................... 509

websteri, Area............................. 509

Scapharca.....___.__......._ 509

cibaoica, Anadara............................. 499

cinnamomea, Botula_____._............ 525

citrinus, Mytilus.............................. 523

Clavinae...................._...._...._ 481

collazica, Turritella.. ......... 458,460,407-468, pi. 71

Turritetta cf. T................. 458,460,467,468

colombiana, Noetia................... ......... 518

Page

colombiensis,Anadara (Grandiarca) grandis... 511,512 

Glycymeris canalis............ ......... 521

Scapharca grandis......................... 512

commutata, Nucula....____._.____ 491

concava, Jupiteria............................. 491

Leda...................................... 490

Nucula.. ........_.....-...-.-...-.--..- 490

concinna,Anadara.......................... 465,501

consobrina, ?Arca cf..._._____.____ 501 

corcupidonis, Anadara......................... 515

cor-cupidonis, Scapharca...................... 514

cosmeta, Bezanconia......... 454,455,472-473, pi. 68

cossmannianum, Dentalium................... 482

costata, Lunarca.............................. 516

Morgania................................. 470

crassa,Arca (Anadara) toroensis............... 509

Crassostrea................................. 509,510

CreneUa. ................................... 522,524

diuturna.................................. 524

divaricata.................... 462,464,524, pi. 80

fCrenella divaricata........................... 524

CreneUa ecuadoriana santiaga.... 462,464,524, pi. 80

emptied................................... 524

crenifera,Adrana....................... 456,465,494

crescens,Arca (Scapharca).................... 509

crossata, Bailya................... 461,462,478,pi. 77

Crucibulum....................... ......_... 474

s.s..-............................ .-.. 474

auriculatum............................... 474

pttiferum............................... 474,475

spinosum.-...........................-... 474

(Crucibulum) piliferum................... 474

spinosum............ 462,464,474-475,pi. 73

Cucuracha formation___.___...___ 457 

cueva, Lunarca............................... 516

Culebraformation...___..__.---....- 456-457

cumanensis, Anadara..............-.....-__ 514

Cunearca........................... 461,513,514,5/6

Cyllndrites.................................... 481

Cymia.. .................................... 455,477

( Tritonopsis) subalveata................. 455,477

n.sp..--..-....-.-- 454, 455, 477, pi. 70

Cyphoma................................... 457,475

gibbosa................................... 475

intermedia.............................. 460,475

aff. C. intermedia......... 457,458,460,475, pl.72

mcgintyi.................................. 475

puana.................................... 475

Cypraea......................... ........... 475

carolinensis............................... 475

(Siphocypraea) problematic............... 475

Cypraeidae__.___..._ ...... 475

D

dalli,Area.................................... 510

Area (Macrodon).......................... 510

dariensis?, Anadara (Rasia) dariensis.......... 461

dariensis, Anadara (Scapharca)................ 501

Area..................................... 501

(Diluvarca)........................... 501

(Scapharca).......................... 501

Scapharca (Scapharca).................... 501

dariensis,Anadara (Rasia).. ___.___ 457, 

460, 461, 462, 464, 465, 50/-502, pi. 77

dariensis?, Anadara (Rasia)............... 461

progonica, Anadara (Rasia) .456, 457, 458, 460,

500, pi. 71

dauleana, Noetia...________.._...... 518

paraguanensis, Noetia..................... 518

davidana, Saccella............................. 494

decussatus, Mytilus........................... 524

deltoideus, Lembulus.......................... 491

democraciana, Glycymeris afl. G............... 522

Glycymeris canalis........................ 522

Dentaliidae....---............-..--........-. 481

dentalina, Ditrupa............................ 486

dentalinus, Cadulus_____.___. __._ 486

Cadulus (Gadilopsis). 462,464, 486-487, 488, pi. 75

Page 

Dentalium.................................. 464,48/

s.s._ 456,482

armttlatum............................... 482

cerinum.................................. 484

cossmannianum......................- 482

dissimtte.. ............................. 483

eboreum................................... 484

elephantinum......... ................ 481,483

equisetum................................- 482

ergasticum...--........................... 483

floridense.-------------------------------- 484

----------------------- 482

..........--.......... - 485

incertum............ --. ...-------.... 485

laqueatum invalidum.^.................... 483

regulare............ ...........-........- 483

ovulum................................... 486

ponderosum..........-------.............- 483

pyrum.................................... 485

quadrapicale- --........................... 483

rectius..... ........-.................... 484

regulare.................. ...---- -- 483

sowerbyi....... ... - 485

sp . 455,481

(Dentalium) armillatum armittatum........ 456,

462, 482, pi. 75 

armillatum proterum..... 456, 464, 482, pi. 71

bothrum..... .....--.-...- 462, 482-483, pi. 75

(Episiphon) innumerabUe elassum......... 462,

464, 485, pi. 75 

(Fissidentalium) esmeraldum.............. 484

granadanum esmeraldum..... 465,484, pi. 75

uscarianum. 456, 457, 458, 460, 488-484, pi. 71 

(Graptacme) sp.. 462,484

(Laevidentalium) pyrum..... 462, 464, 485, pi. 75

sp...... 485

(Laevidentaliumf) sp.........-.........- 455,485

(Rhabdus?) s^>............... 462, 484-485, pi. 75

(Tesseracme) dissimile....... 462, 464, 483, pi. 75

dissimtte dissimile..................... 483

Description of Tertiary moUusks.... ...-- 465-528

Diluvarca.................................-- 500

diluvii, Area.-----.--- . - 500

fArca (Anadara)......................-.. 501

Diplocyma.. _-------------------.------------- 471

dissimile, Dentalium......................----- 483

Dentalium (Tesseracme)..... 462, 464, 483, pi. 75

dissimile, Dentalium (Tesseracme)......... 483

Ditrupa dentalina...................---------- 486

diuturna, Crenella..........................-- 524

divaricata, Barbatia.......................... 497

Byssoarca..........-..,.----------------- 497

CreneUa.............. . 462, 464, 524, pi. 80

?Cren^o.......------------------------ 524

Nucula...... -------....-------------- 489

Nuculocardta ----------------------------- 524

dodonaius, Xancus........-------------------- 480

praelaevigatus, Xancus.-..------ 462,464,479-480

dolaticosta, Anadara (Grandiarca)......-....... 462,

464,5/0-5//,513,pl. 80 

Area 510

dottchus, Cadulus (Gadilopsis)........ 455,456,pi. 70

doma, Anadara singewaldi..................... 506

si*, Acar......... 460,462,464,497-498, pi. 77

?, Acar.... .. - 458,460

a, Area. 497

Barbatia (Acar) 497

fBarbatia (Acar) sp. cf. B. (Acar)......... 497

donacia, Anadara....... .... ............... 499

drymanos, Glycymeris....... ...--------------- 520

dumblei, Globularia recurva................ -- 455,476

E

eboreum, Dentalium............. ...- -- 484

Echinophoria -.......... -- - ---- - 476

ectypha.Neritina............. . . 454, 467, pi. 67

ecuadoria, Noetia............................. 518

Noetia (Noetia).. .----------- 518

ecuadoriana santiaga, Crenella..... 462,464,524, pi. 8°
536 INDEX

Page 

edulis, Mytilus................................ 522

elaschistum, Teinostoma (Idioraphe)........... 454,

455,467, pi. 70

elassum, Dentalium (Episiphon) innumerable. 462,

464,485, pi. 75 

elegantissimus, Cadulus....................... 486

elephantinum, Dentalium................... 481,483

ellipttca, Crenetta............................. 524

emarginata, Anadara........................ 465,504

Anadara (Rasia) cf. A....... 462,465,504, pi. 77

emendorferi, Hannatoma..................... 455,471

Hannatoma? cf. H...................... 454,470

Emperador limestone member of La Boca formation............................ 457-160

Engina....................................... 477

floridana.................................. 477

panamensis............................... 478

tabogaensis................................ 473

turbinetta................. 462,464,477-47S,pi. 74

zonata.................................... 477

Ennucula................................... 454,459

Enzina....................................... 477

Eocene series......... ................... 454-155

Eontia........................................ 518

epacra, Glycymeris (Tucetona). 162,464,520,522, pi. 81 

Saccetta acrita........ 462,464, 492-493, 494,pi. 75

epelys, Bayania............... 454,455,468-469,pi. 68

epetrion, Cadulus (Platyschides)....... 462,487,pi. 75

ephippium, Ostrea............................ 527

Episiphon.................................... 485

epistomifera lipara, Cancellaria (Cancellaria).. 481 

sathra, Cancellaria (Cancellaria')........... 48t

equisetum, Dentalium......................... 482

ergasticum, Dentalium......................... 483

esmeraldum, Dentalium (Fissidentalium)....... 484

Dentalium (Fissidentalium) granadanum... 465,

484, pi. 75 

eumeces, Anadara (Cunearca)......... 462, 616, pi. 77

euthynta, Portlandia (Portlandettaf)... 44, 495, pi. 70 

exigua, Nucula.............................. 465,488

Exputens______.____._______. 455,527 

alexi.____._______.________ 527 

bostrychodes.................. 454,455,508, pi. 68

. 527

F

fabalis, Saccella ci. S................. 462, 493, pi. 77

falconensis, Xancus........................... 479

Xancus validus.......................... 463,479

fastigata, Saccella........................... 465,494

Faunal summaries_____.____...__ 454-465 

Faunus____ __._.._____..... 454,455,469

ater................................. 455,469,470

melanopsis................................ 469

xenicus.................. 454,455, 469,470, pi. 69

filicata, Anadara aff. A........................ 514

fissicosta, Anadara (Rasia).................... 461,

462, 464, 506-606, pi. 78 

Anadara (Rasia) cf. A................... 461,506

Area (Scapharca)......................... 505

Fissidentalium.......................... 456,483,485

flabeUatus, Glycymeris......................... 520

Pectunculus.............................. 520

Uoridana, Anadara.......................... 503,504

Area...................................... 500

Engina..................______..... 477

Trochtta.................................. 474

floridense, Dentalium.......................... 484

fluviatilw, Tymponotonos...................... 471

fluviatUls [fluviatilis], Tymponotonos........... 471

formosa, Area,................................. 499

fragilis, Area.................._............... 491

Ledina.................................... 491

fusca,Botula........................... 460,464,525

fusca?,Botula........................... 458,460,505

fuscatus, Murex............................... 471

fuscus, Mytilus................................ 525

Fusus marnochi............................... 472

G

Page

gabbi, Typhis (Pilsbrytyphis)................ 462,477

Gadila........................................ 486

Gadilopsis.............................. 455,486,487

gardnerae, Noetia............................. 518

garitensis, Anadara........................... 509

Gastropods__________._._.._ 465-481 

Gatunformation.. _. -__- _ -.- 461-465 

Gatuncilloformation.--------------_----- 454-455

gatunensis, Area.............................. 501

n. f., aff. Axinaea albolineata, Pectunculus

(Axinaea)........................ 519

geraetera, Anadara santarosana.... ..--..---. 460,507

gesteri, Hannatoma........................... 471

gibbosa, Butta................................. 475

Cyphoma................................. 475

Ovula.................................... 475

Globularia.................................. 455,475

s.s......,__._._____-...................... 475

patula.................................... 476

recurvadumblei......................... 455,476

recurva............................... 476

(Globularia) megista....... 454,455,475-476, pi. 67

Globulariinae...___............__..--.- 475

Glycmerididae..._----------------_------ 519

Glycymeris.................................... 519

s.s........................................ 519

acuticostata............................... 520

arctata.................................. 521,522

canalis.................................. 520,521

^Glycymeris canalis........................... 520

Glycymeris canalis colombtensis................ 521

canalis democraciana...................... 522

canalis, var...______--------------- 522

caracoli................................. 455,519

carbasina................................ 519

carbasinaf................................ 519

aff. G. democraciana...................... 522

drymanos.---............................. 520

flabellatus.. ---------------------------- 520

jamaicensis--------...................... 520

lamyi................................... 521,522

tampae.................. ........... 521

lloydsmithi.......................--. 520,522

multicostata........................... 522

striatidenta........................... 522

multicostata............................... 522

orbicularis..............................- 519

pectinata................................. 520

pectmata............................. 521

schencki.................................. 521

secticostata......................-. ...... 520

secticostata.....-..........---.--. 460,522

subovata............................. ... 520

undata........... . ................... 520

usiacurii.................................. 522

(Glycymeris) cf. G. caracoli.... 454, 455, 5f9,pl. 69

carbusina. 158,4f0,462,464, 519-520, pi?. 79, 81 

( Tucetona) epacra........ 462,464, 520, 522, pi. 81

pectinata canalis...................... 460,

461,462,464,500-50/, pi. 81 

pectinata canalis?....... .- 458,460,461

secticostata schencki................... 458,

460,462,465,5^-500, pis. 72, 75

sp. . 458,461,465,520,521

glycymeris, Area........ .................... 519

gouldii, Dentalium............................ 482

gradata, Acar................................. 498

granadanum esmeraldum, Dentalium (FissidenUium).. .465,484, pi. 75 

Grandiarca................................. 464,508

grandis, Anadara (Grandiarca)..... ..... 464,508

Anadara (Larkinia).....-......... ...... 512

Area...-................ . 508,511,512,513

Cadulus....... ........................... 487

Scapharca (Scapharca)..... .___----- 512

cedralensis, Scapharca..... .. .......... 512

colombiensis, Anadara (Grandiarca)..... 511,512

ScapAorco.------------__------_------ 512

Page

grandis Continued

grandis, Anadara (Grandiarca)...... 511,512,513

patncta, Anadara (Grandiarca)...... 511,512,513

patriciaf, Anadara (Grandiarca)........... 462,

464, 612-613,pl. 79 

waringi, Area.... .............. ..... 512

granosa, Anadara............................. 499

granulosa, Nerita..........------------------- 466

Graptacme.. ....................... 484,485

guajactica, Anadara........................... 499

H

hadra, Nerita......................... 454,466,pl.67

Hannatoma. ...................... 455,470

antyx.................. 454, 455, 470-471, pi. 68

emendorferi............................. 455,471

Hannatoma? cf. H. emendorferi........ . - 451,470

Hannatoma gesteri................ ........... - 471

tumbezia...........................--..... 471

harrisi, Atrina................................ 526

Teinostoma.---...-------- . 455,467

Harrisianella.-- .-.---------- 455,470

camptica..................... 454,455, 470, pi. 69

peruviana..... ........... -............ 472

plicifera................................. 472

Hawaiarca.. ........................ 456,498-499

rectangula........ ......... ... -....- 498

haytense, Dentalium........................... 485

hendersoni, Cadulus...------------------------ 487

hilli, Nucula (Nuculopsis).................. 454,489

hillsboroensis, Cerithmm............ ... 471

hindsi, Anadara............. ................ 515

hirundo, Mytilus............ . ----- ---- 526

hispaniolae, Botula..............-------------- 525

honensis, Anadara..... .. ... ............. 502

adiaphora, Anadara (Rasia)..... 465, 502, pi. 82

honensis, Anadara.... ........... ....- 465

hopkinsi, Anadara............- - ----- 507

hyphalopilema, Anadara.................... 461,507

hystems, Xancus validus..... 462,479, 480, pis. 73, 74

Idioraphe..............................------- 467

imbricata, Area...... 461, 462, 464, 496, pis. 73, 77

Area (Area).. -.- - 496

imporcata, Area (Scapharca).------- -------- 509

inaequilateralis, Anadara... ... ----------- -- 510

inaequivalvis, Area--......... - .. -... 498

incertum, Dentalium................ 485

incognita, Saccella................... .....-- 492

incongrua, Area......................-. -- - 516

innumerabtte elassum, Dentalium (Episiphon). 462,

164,485, pi. 75 

inornata, Pteria.... - - - 460,526

inornata?, Pteria....... 458, 460, 162, 526, pis. 73, 80

intermedia, Cyphoma.. .... .-... .-- 460,475

Cyphoma, aff. C......... 457, 458, 460, 475, pi. 72

intricatus, Phos............------------------- 478

Introduction,_.- . - ---- 453

invalida, Area....... .... ... .. -- 510

invalidum, Dentalium laqueatum.............. - 483

Isognoma....................----------- -- 526

lignea.------...------ - - - -- 526

Isognomon..................... ...-... -- 454,506

s.s.. ... - - 527

flsognomon sp. --------- - ----- - 527

Isognomon (Melina?) sp..... 462, 527, pi. 80

(Mimonion) mimeticus......... ......---- 454,

457, 458, 526, 507, pi. 71 

isognomon [isognomum], Ostrea................ 526

Isognomoiiidae---.. ._. --------- 4o4,526

isognomum, Ostrea.......... - ...---- ----- 526

isthmica, Acila (Acila).-.....------------ 489

Nucula (Acila). - - 489

burica, Acila... . - 490

isthmica, Acila (Acila)..........------ -- 456,

458, 460, 462, 464, 465, 489-490, pis. 70, 

71, 76, 82
INDEX 537

Page

istmica, Anadara.............................. 503

fAnadara (Anadara)...................... 503

jamaicensis, Olycymeris....................... 520

Jupiteria................................... 490,491

aipeia........................ 456, 490-491, pi. 72

brocchii................................. 456,491

concava................____._._.. 491

subtumida................................ 491

subtumida?...................... 462, 491, pi. 75

K

karsteni, Architectoniea (Architectoniea) nobilis. 473

labettata, Calyptraea........................... 474

La Boca formation, including Emperador

limestone member__.__.,_ 457-460 

lactea, Bayania........................ 455,468,469

Laevidentalium................................ 435

laevigata, Calyptraea.......................... 473

laevigatus, Xancus............................ 480

lagunitensis, Tympanotonos................... 471

lamarcki [lamarckii], Volvaria.................. 481

lamarckii, Volvaria............................ 481

lamyi, Olycymeris........................... 621,622

tampae, Glycymeris........................ 521

lanceolata, Nucula............................ 494

laqueatum invalidum, Dentalium.............. 483

regulare, Dentalium....................... 483

Larkinia...................................... 508

larkinii, Anadara............................. 508

Area..................................... 508

Leda acuminata............................... 494

balboae.................................... 493

concava................................... 490

peruviana................................. 494

rosa...................................... 496

solida..................................... 491

solidifacta................................. 491

taylori.................................... 494

fLeda sp_________._.........___ 493

Leda (Adrana) newcombi...................... 495

Ledina....................................... 491

fragilis.................................... 491

Lembulus deltoideus........................... 491

leonensia, Colloarca........................... 497

Leptadrlllia................................... 481

Leptadrilliaf.................................. 48!

n. sp............................. 454,48jf.pl. 69

Leptomurex............................ 454,455,476

acares................... 454,466, 476-477, pi. 68

leptus, Charadreon............... 454, 469, 471, pi. 68

lesueuri,Arca................................. 504

Scapharca................................ 505

lienosa lienosa, Anadara....................... 503

secticostata, Anadara.................... 503, 504

trochala, Anadara (Easia) 462,464,503-504, pi. 76 

lignea, Isognoma.............................. 526

limonica, Area................................ 514

lipara, Cancellaria............................ 481

Cancellaria (Cancellaria) epistomifera...... 481

lispa, Calyptraea................. 454, 473-474, pi. 69

Lissanucula. __._ ____ 454, $9 

listrota, Nerita................... 464, 456, 466, pi. 69

lita, Anadara (Rasia)........ 455,466, 504-505, pi. 70

Hajasensis, Exputens.......................... 527

lloydsmithi, Olycymeris........ .......___ 520,522

multicostata, Olycymeris................... 522

striatidenta, Olycymeris.................... 522

longicauda, Ostrea............................. 527

Vulsella.................................. 527

losquemadica, Scapharca....................... 501

Lunarca...................................... 516

costata---..-.............................. 516

cueva..................................... 516

ovalisf....................... 462, 516-517, pi. 79

M

Page

macdonaldi,Arca............................. 618

Area (Noetia). ......................... 618

Noetia.................................... 618

(Noetia) reversa....................... 462,

464, 518-519, pis. 81,82 

alta, Noetia..................... ..... 618,619

subreversa, Area........................... 618

truncata, Noetia........................... 618

MaUeidae.........-- ...................... 627

maracaibensis, Anadara zuliana............... 606

margaretae, Anadara.......................... 502

Marine member of Bohio(?) formation.__ 455 

mar ksi, Anadara.............................. 503

marnochi, Fusus.............................. 472

martyria, Yoldia....... .. . ..... . 495

matarucana, Anadara veatchi.................. 508

mauryae, Noetia............------------- -- 518

mcgintyi, Cyphoma................. 476

medioamericana, Anadara................... 460,502

Anadara (Rasia) cf.A.............. 458,460,502

megista, Globularia (Olobularia)............... 454,

465,475-470, pi. 67

Melanopsinae__-_.--.._..._-_.-.- 469 

melanopsis, Faunus........................... 469

Melina ..................................... 627

Melina?....................................... 527

Melongena.................................... 478

propatula... ______-________--- 478 

cf. M. propatula............. 452, 478-479, pi. 73

Melongenidae__._____________-.- 478 

meroensis, Anadara........................... 506

micraulax, Potamidesf.........--... 454,470, pi. 69

microtera, Anadara.............--------------- 506

mimeticus, Isognomon (Mimonion)............. 454,

467, 458, 525, 627, pi. 71 

Mimonion.......................... 454,467, 626-527

Mocene series..-----_____----_-----.--- 456-466

Mississiyiensis, Anadara................ 458,504

Area.-.-.-.-......-... - 606

Brachidontes............... 460,523

Byssoarca.............................. 505

Mitridae..--.. - .... ..-- ..-- - 481

Modiolasulcata-..................- ......... 623

tulipa....... ............................. 523

Modiolus..................................... 523

americanus---------------------- 460,523,624

americanus"!. ............ 468,460, 523-624, pi. 72

pseudotulipus................ ... 524

waringL.................................. 523

Modiolust SV-............................... 454,523

modiolus,Arca................................ 523

Mytilus...................... - ..- 523

morantensis, Area (Area) umbonata........ _- 496

Morgania costata..........____--__ 470

multicostata, Olycymeris....................... 522

Glycymeris UoydsmiM..................... 522

multicostatus, Pectunculus [Olycymeris]........ 522

Muracypraea.................-...------------ 475

Murexfuscatus.-........------------ ------ 471

Muricidae. . 454,476

Mytffidae.. _ 622

MytUoperna.............................-.... 627

americana.-------------------------- -- 627

Mytilus . 622,527

canoasensis Mali............. ...--------- 466,

457, 458, 460, 451, 462, 464, 622-623, 527, 

pi. 73 

citrinus................................... 523

decussatus.....................----__- 524

edulis.. ..-. . 622 

fuscus..................---------_____ 625

hirundo... ______.......................... 626

modiolus.................................. 523

vidali..........-........ ............. 522

sp 522

MytUusf sp.-.- 623

N

Page

Naticidae....... --... - 476

nelsoni,Arca (Anadara).. ...... ......... 509

Nerita... 465-466

s.s.?. . ... . - -- - 466 

granulosa. ...... .. ..... ...... ......... .... 466

hadra. . - 454, 466, pi. 67

listrota ... 454, 455, 466, pi. 69 

peloronta.... ... ........ ...... .... ... ..... 465

planospira ... .. ..... 466,463

(Neritaf) sp...... . 458,4^, pi. 73

Neritidae... 465

Neritina .. 454,4<?<?

ectypha. ....... ..---... - .....-. 464, 467, pi. 67

sp 454, 4<?7, pi. 69

Neritinae..... --. -- - 465

newcombi, Adrana. .... ... .. ... .. 496

Adranact.A..... .--- 462,494-495

Leda (Adrana) ........ .... ... .... ...... ... 495

New generic and subgeneric names. 454 

nigra, Pinna ...... .......... ....... ..... ...... 626

noae,Arca..... ... ... .... ... . ... -------------- 496

nobilis, Architectoniea (Architectoniea) cf.A .... 468,

460,473

karsteni, Architectoniea (Architectoniea)..-- 473 

nobilis, Architectoniea. ...... .... .... 460,473

subsp., Architectoniea (Architectoniea) .... 458,

460, 473, pi. 71 

Noetia..... 617

colombiana .... . .. ..... . 618

dauleana. ... .... _ - --------- . 618

paraguanensis.----- ... ........... ... - 618

ecuadoria.. ..... . ... ... ... ---------------- 618

gardnerae. __ _ _ ---- -. 618

macdonaldi ...... ....... ........... ..... ... 618

alta - .----..... ....---. 518,619

truncata-.... .... . ... . ... ... --- 618

mauryae- .......... 618

reversa....-... ...... ... ... ... 519

sheldoniana...- ........ . --.... ...- 517,618

triangularis ......... ... .. ... .. . .. 617

vientoensis.---- ....... ... . ... ... ... ..... -. 617

(Noetia) ecuadoria ........ ....... ... . ... --- 618

reversa macdonaldi--..., ........... ... 462,

464, 518-619, pis. 81, 82

Noetiidae... ___. - --- - - 517 

Noetiinae. .............. . . -- 617

notabilis, Anadara ....... .. ... -... - ----- 504

nucleus, Area .... ...... .... ------------ ---- 488

Nucolopsis ... ...... .. - 489

Nucula 4«S,489

s.s 488,489

[Leda] acuminata ....... . 494

arctfaj . 496

cahuitensis .- ...... . 488,490

commutata.. .... ... . .... ... ... ... - ------ -- 491

concaoa.-.- .... ....... ... -...-. ....... -. 490

divaricata,. ........... 489

exigua.... 466,488

lanceolata ... . ... . ... . ... ... ------- 494

obligua........ ........ - --- 489

spheniopsis.... .... . -... - .....-....... 466,488

tenuisculpta ......... . ... -- ... ... ------- 488

venezuelana ... ... . ... .... .... ------------- 488

vieta... 488

(Acila) isthmica 489

(Nucolopsis) schencki ... . . .-.. . ...... ... 489

(Nucula) cf. N. cahuitensis- 462, 466, 488, pi. 76

cf. N.spheniopsis . 456, 488, pi. 70

tenuisculpta.. 462, 464, 488-489, pi. 76

(Nuculopsis) hUli. 454,489

Nuculanidae. . . - _ -------- - ---- 490

Nuculidae 454,488

Nuculocardia divaricata.... ... - - 524

Nuculoma.. ... __ 489

Nuculopsis. .......... --- -.-- - .. . .. 489

nux, Anadara ... ...... ..... ....... .... ........ 614
538 INDEX

Page 

obesifarmis. Area.............................. 509

Area (Scapharca)......................... 509

(Senilia) chiriguiensis................. 509

obliqua, Nucula......... ....____-....--.. 489

ocalensis, Vulsella............................. 527

Ocenebrinae?_______._________ 454,476 

ocoyana, Turrttella............................ 468

Ollgocene series_______.__.__.. 455-456 

Omniglypta................................... 484

opthanta, Barbatia (Diluvarca)............. _- 514

orbicularis, Olycymeris........................ 519

ornate, Saccella............................. 465,493

SacceUact. S............................ 465,493

Orthaulax aguadillensis....................--.. 511

Ostrea ephippium............................. 527

isognomon [isognomum].................... 526

longicauda................................ 527

avails, Area................................... 516

ovalisf Lunarca.................. 462,5/0-5/7, pi. 79

ornlis, Samanoetia............................. 517

Ovula gibbosa................................. 475

Ovulidae..- .__ .- - -- - 475 

ontlum, Dentalium............................ 486

packardi, Saccella............................. 492

paezensis,Arcaumbonata..................... 496

panamensis, Cadulus.......................... 487

Engina................................... 478

paraguanensis, Noetia dauleana............... 518

parkeri, Tunis (Surcula)...................... 481

parvus, Triton................................ 478

patriarcha, Area............................... 513

patricia, Anadara (Orandiarca) grandis.. 511,512,513 

patriciaf Anadara (Orandiarca) grandis........ 462,

464,5/2-5/3, pi. 79 

patricia, Anadara (Larkinia).................. 512

Area................................ 464,512,513

Scapharca................................ 512

Scapharca (Scapharca).................... 512

waringi, Scapharca........................ 512

patula, Olobularia............................. 476

pectinata, Olycymeris.......................... 520

canalls, Olycymeris (Tucetona)............ 460,

461,462,464, 520-521, pi. 81 

canalist, Olycymeris (Tucetona)..... 458,460,461

pectinata, Olycymeris...................... 521

PectunculusflabeUatus........................ 520

[Olycymeris] multicostatus................. 522

tPectunculus spec. Ind. (n. sp?)_____ - 520 

Pectunculus (Axinaea) gatunensis n. f., aff. 

Axinaea albolineata......................... 519

Pelecypods -- - - _- - 488-528 

peloronta, Nerita.............................. 465

pennetti, Anadara............................. 506

Area..................................... 513

perfaceta, Area................................ 514

Perna americana.............................. 527

perplura, Anadara............................ 506

perprotracta, Adrana.......................... 495

Yoldia ................................. 495

perpusiUus, Cadulus.......................... 487

peruviana, HarrisianeUa...................... 472

Leda..................................... 494

SacceUa.................................. 494

pexata, Area.................................. 516

phalacra, CaUoarca........................... 497

phlyctaena, Saccetta............ 455, 491-492, pi. 70

Phos intricatus................................ 478

pttiferum, Crudbulum...................... 474,475

Crucibulum (Crudbulum)................. 474

Pusbrytyphis................................. 477

pUula,Arca.................................. 513

Pinna assimilis............................... 525

nigra..................................... 525

vexittum.................................. 525

Page 

Pinnidae................--.-------..-------- 525

pittieri, Anadara ............ .. ................ 515

planospira, Nerita.. ........ . ... .. .... ...... 455,466

Platyschides. ..................... ... ......... 487

Pleurotoma tantula.. .... ... - .... --- - 481

plicifera, HarrisianeUa. ....... .... ........... . 472

PoZj/scAzdes. --------------------------------- 487

pomponiana, Area. ..... . ... ... ------ .... .. 514

ponderosum, Dentalium... _ ------- - --- 483

Portlandetta. ................................. 495

Portlandia..... ............................... 495

s.s.-.---. _ ...........--------.---------- 495

(Portlandellaf) euthynta. -- 455,495, pi. 70 

P^amides. ............................. 470,471,510

Potamidesf micraulax. --------------- 454, 470. pi. 69

Potamidinae.. --. --- --- -- 470 

Potiarea.. .......................... 461, 5/3-5/4, 516

(pttula) saccula.. .... ....- ... .... ... . 513

praelaevigata, Turbinella ------- ... . ...... 479

praelaevigatus, Xancus dodonaius .... 462,464,479-480

praeovoidea, Turbinella ...... .................. 479

praeovoideus, Xancus.. ....... ...... ........ 479,480

praevoideus, Xancus... ...... ----- .- 479

precursor, Ultimus. .............. . ........... - 475

prenanum, Teinostoma (Idioraphe).. ...... . ... 467

problematica, Cypraea (Siphocypraea) ......... . 475

progonica, Anadara (Rasia) dariensis... ....... 456,

457, 458, 460, 500, pi. 71 

prolata, Area (Anadara) toroensis ... ........ ... 509

propatula, Melongena. ........... 478

Melongena cf. M. ............. 462, 478-479, pi. 73

proterum, Dentalium (Dentalium) armittatum.. 456,

434, 482, pi. 71 

Pseudofaunus ....... .. ..... - ______ -. __ 469

bravoensis ......... .. ..... ....... . ...... ... 469

Pseudomelaniidae. _ .. ___ _____ - _ - 468 

Pseudomelaniidae? ___ . _______ ... 454,469 

pseudotulipus, Modiolus ................... .--- 524

Pteria.. ...................................... 526

argentea... ............................. .. 526

inornata _________ ___ ___ 460,526 

inornatat .......... 458, 460, 462, 526, pis. 73, 80

Pteriidae. -- -..... -- - ---- . 526

puana, Cyphoma ...... . .... ........ ... .... ... . 475

puntabravoensis, Samanoetia ...... - 517

pupoidea, Bezanconia _________ - _ --- 472 

Purpuraturbinella... .. . . - __ .. __ 477

py rum, Dentalium... ..... . ... . .... .-- ....... . 485

Dentalium (Laevidentalium).. 462, 464, 485, pi. 75

Q

guadrapicale, Dentalium.... ......... -... 483

R 

radians, Trochita......______.-_-__ 474

Trochitacl. T... 474

Rasia........................... 455,461,499-500,513

rectangula, Hawaiarca............. .___. 498

rectius, Dentalium................-............ 484

recurvadumblei, Olobularia.................. 455,476

recurva, Globularia...............---. -- 476

References cited-----.---..-------.----- 528-531

regulare, Dentalium........................... 483

Dentalium laqueatum........ ....... 483

reticulata, Barbatia (Acar) ..................... 497

reversa, Area...............____.___--.. 517

Noetia..................... ............ 519

macdonaldi, Noetia (Noetia)............... 462,

464, 518-519, pis. 81, 82 

rex, Xancus............................__... 479

Xancus cf. X....................... 457,459,479

Rhabdusf..................................... 484

riocanensis, Scapharca......................... 514

rondeleti, Semicassis........................... 476

roaa, Leda.................................... 495

Page 

Sacetta...... .............................. 490

acapulcensis.............................. 492

acrita..................................... 493

acn'to...-_--------------------- 492,493

epacra. ... . 462,464,492-493,494, pi. 75 

acuta............................... 455,491,492

balboae..... 457,460, 462,464,465, 493-494, pi. 77

aff. S. balboae................... 457, 458, 460, 493

canonica..................... ._._._.. 493

davidana.................................. 494

cf. S.fabalis...................... 462, 493, pi. 77

fastigota................................ 465, 494

incognita...........-____________ 492

ornata.................................. 465,493

cf. S. ornata........--.......... ....... 465,493

packardi.................................. 492

peruviana................................. 494

ptilyctaena.................... 455, 491-492, pi. 70

subcerata............................... 456, 492

cf. S. subcerata.................. 456, 492 pi. 71,

sp...-.... .- .- - - 454, 49/

(elongate)..... 458, 493

(fine sculpture)... .. - 457,458, 491 

saccula Potiarea (pilula)...................... 513

samanemis Area (Argina).................... 517

Arginetta. ..... ..................... 517

Samanoetia....................... 455,5/7 pi. 70

Samanoetia................................. 455, 517

oualis..................................... 517

puntabravoensis........................... 517

samanemis...................... 455, 5/7, pi. 70

santarosana geraetera, Anadara.............. 460,507

santiaga, Crenella ecuadoriana.... 462,464,524, pi- 80

sathra, Cancellaria (Cancellaria) epistomifera.. 48!

Scapharca... _______.__________ 498

chiriguiensis.............................. 508

bolivari............................... 509

wefcrferi...---------------------------- 509

cor-cupidonis............................. 514

grandis cedralemis........................ 512

eolombiensis.......................... 512

lesueuri................................... 505

losguemadica.............................. 501

patricia................................... 512

waringi........__.__ .__----- 512

riocanensis................................ 514

(Scapharca) actinophora................... 502

balboae............................... 510

chiriquiensis.......................... 508

dariensis.............................. 501

grandis.............................-- 512

patricia............................... 512

Scapharea.................................... 498

Scaphopods....----.-------------------.-.- 481-488

schencki, Glycymeris.......................... 521

Glycymeris (Tucetona) secticostata......... 458,

460, 462, 465, 521-522, pis. 72, 75 

Nucula (Nucolopsis)...................... 489

secalis, Bayania............................... 469

sechurana, Anadara (Rasia) 462, 464, 505, 506, pi. 79 

Area (DUuvarca).......................... 505

Sectiarca_____________________ 500,504 

secticostata, Anadara lienosa.. ............... 503,504

Olycymeris.............------...-.....---. 520

schencki, Olycymeris (Tucetona)........... 458,

460, 4-i2, 465, 521-522, pis. 72, 75 

secticostata, Glycymeris.................. 460,522

sellardsi, Area (Anadara)...................... 508

Semicassis................._________.. 476

rondeleti.................................. 476

(Echinophoria) tostoma.......... 458, 476, pi. 71

semidecussata, Bayania........................ 469

Senilia........................................ 508

sen&is.................................... 508

senilis, Area.................................. 508

Senttia.................................... 508

septifera, fArca............................... 509

fArca (Anadara).................... ._ 509

fArca (Senilia) chiriguiensis............... 509
INDEX 539

Page 

serrata,Atrina.............................. 465,526

Atrina (Servatrina) aft. A................. 462,

465, 526-626, pi. 82 

Servatrina.................................... 526

sheldoniana,Noetia..._..................... 517,518

singewaldi, Anadara........................... 506

doma,Anadara..... _____._______ 506

Siphocypraea................................. 475

Siphonochelus (Pilsbrytyphis) w oodringi....... 477

Siphonodentallidae_.____.___.__. 486 

solida, Leda.....................___.___ 491

solidifacta, Leda............................... 491

sowerbyi, Dentalium........................... 485

spheniopsis, Nucula......................... 456,488

Nucula (Nucula) cf. N.......... 456, 488, pi. 70

spiekeri, Anadara............................. 506

Anadara cf. A............................ 506

spinlformis, Cadulus (Gadila)................. 187

spinosa, Calyptraea........................... 474

spinosum, Crucibulum........................ 474

Crucibulum (Crucibulum)................. 462,

464, 474-476, pi. 73 

spirata, Bezanconia......................... 455,743

Trochita.................................. 474

spirata?, Trochita................... 462, 474, pi. 72

spiratum, Cerithium........................... 472

stena.Adrana............... 455, 456, 435, 494, pi. 70

striatidenta, Glycymeris Hoydsmithi............ 522

Strombus ater................................. 469

subalveata, Cymia (Tritonopsis)............. 455,477

subalveatum, Triton........................... 477

subcerata, Saccella........................... 456,492

Saccettacf. S..................... 456,492, pi.71

subcrenata, Anadara.......................... 499

subgrundifera, Turrttella.......... 458,460,^8,pi. 74

TurriteUa cf. T..................... 458,460,468

subovata, Glycymeris.......................... 520

subreversa, Area macdonaldi................... 518

subtumida, Jupiteria.......................... 491

subtumida?, Juptteria................. 462,49J,pl. 75

sulcata, Modiola............................... 523

sulcicosta, Anadara............................ 499

sit, Engina........................... 478

Taeniarca..................................... 497

taeniata, Barbatia (Calloarca).................. 497

Barbatia (Cucullaria)..................... 497

Calloarca................................. 497

tampae, Glycymeris lamyi...................... 521

tantula, Pleurotoma........................... 481

taylori, Leda.................................. 494

tectumcolumbae, Anadara.................... 461,507

Anadara (Tosarca) cf. A.......... 461,507,pi. 73

Teinostoma................................... 467

harrisi.................................. 455,467

verrttli- ............................... 467

(Idioraphe) elaschistum........ 454,455, 467, pi. 70

prenanum............................ 467

Telescopium.................................. 470

tenuisculpta, Nucula.......................... 488

Nucula (Nucula)......... 462,464,488-488,pi. 75

Tesseracme................................. 464,483

Thaidinae-. . _ 477 

Thiaridae.................................... 469

tolepia, Anadara.............................. 506

Toro limestone member of Chagres sandstone.. 465 

toroensis,Arca (Anadara)..................... 509

Area (Senilia) chiriquiensis................ 509

crassa,Arca (Anadara).................... 509

prolate, Area (Anadara)................... 509

Page 

tosaensis, Anadara (Tosarca).................. 506

Tosarca..................................... 464,506

tostoma,Semicassis(Echinophoria)..... 458,476, pi. 71

transversa, Anadara........................... 505

triangularis, Noetia........................... 517

Triton anomalus.............................. 478

parvus.................................... 478

subatveatrm............................... 477

Tritonopsis . .......................... 455,477

trochala, Anadara (Rasia) lienosa............... 462,

464, BOS-504, pi. 76 

trochiformis, Trochita....................... 462,474

Trochita? cf. T......................... 458,474

Trochita...................................... 474

floridana.................................. 474

radians................................... 474

cf. T.radians............................. 474

spirata.................................... 474

spirataf........................ 462, 474, pi- 72

trochiformis............................ 462, 474

Trochita? cf. T. trochiformis....----.-----.-- 458,474

Trochita sp................................. 458, 474

TVocMtof sp 458,474

truncata, Noetia macdonaldi................... 518

Tucetona.................. .__________ 620

tulipa, Modiola................................ 523

tumbezia, Hannatoma......................... 471

Turbinellapraelaeeigata....................... 479

praeovoidea............................... 479

turbinella,Engina............ 462,464, 477-478, pi.74

Purpura.................................. 477

Turridae..................................... 481

Tunis (Surcula) parkeri...................... 481

Turrttella..................................... 467

abrupta................................... 468

coUazica. ................. 458,460, 467-468, pi.71

cf. T.collazica.................. 458,460,467,468

ocoyana................................... 468

subgrundifera................ 458,460, 468, pi. 74

cf. T. subgrundifera................ 458,460,468

Turritellidae...-_. 467

Tympanotonos....................... 454, 455, 471

acanthodes-. 454, 455, 471-472, 473, pis. 68, 69 

lagunitensis ............................. 471

sp - - - 455

Tymponotonos fluviatttls [fluviatilis].........--- 471

Typhinae...___..--_..__-.-__--...-- 477 

Typhis.................-...--..-.....---..--. 477

(Pilsbrytyphis) gabbi.................... 462,477

woodringi........................... 462,477

U 

Ultimus precursor............................. 475

umbonata,Arca............. .................. 496

Area (Area)............................... 496

morantensis,Arca (Area).................. 496

paezensis, Area........................... 496

undata, Glycymeris............................ 520

uscarianum, Dentalium (Fissidentalium)....... 456,

457, 458, 460, 483-484, pi. 71 

usiacurii, Area (Anadara).................... 511,512

Glycymeris................................ 522

V 

validus, Xancus............................ 457,479

Xancus cf. X.................. 457, 458, 460, 479

validus?, Xancus validus.................... 462, 479

validus falconensis, Xancus................. 463,479

hysterus, Xancus........ 462,479,480, pis. 73, 74

validus, Xancus........................... 479

validus?, Xancus....................... 462,479

Page 

veatchi,Andara (Tosarca)................... 461,507

Veatchi,Arca................................. 507

veatchi, Area (Scapharca)...................... 507

Area (Scapharcaf)........................ 507

matarucana, Anadara..................... 508

veatchi, Anadara (Tosarca)................ 462,

464, 607-608, pi. 78 

venezuelana, Nucula.......................... 488

verriUi, Teinostoma........................... 467

vexillum, Pinna............................... 525

vidali, Mytilus................................. 522

MytUus canoasensis....................... 456,

457, 458, 460, 461, 462, 464, 622-623, 527, 

pi. 73 

vientoensis, Noetia............................. 517

vieta, Nucula................................. 488

VitrineHIdae--. 467

Volsella...................................... 523

Volvaria lamarcki [lamarckii\................... 481

Volvarietta.................................. 455, 481

aldrichi................................... 481

Volvarietta? sp....................... 455, 481, pi. 70

Vulsellalongicauda.-..-------------..--.----. 527

ocalensis.................................. 527

W

waringi, Anadara (Grandiarca).............. 511,512

Anadara (Larkinia)....................... 512

Arcagrandis...........................--. 512

Modiolus...........'.........-............ 523

Scapharca patricia. -..................... 512

websteri,Arca................................. 509

Area chiriquiensis......................... 509

Scapharca chirigu iensis.................... 509

woodringi, Siphonochelus (Pilsbrytyphis)....... 477

Typhis (Pilsbrytyphis)........--.... . 462,477

woodsi, Bezanconia........................... 473

X

Xancid?, genus?. .. - - 461,462, 480, pi. 73 

Xancidae - 479

Xancidae?. - 480

Xancus...........--.......-.........--- -- 479

dodonaiws.......................... 480

praelaevigatus.............. 462, 464,479-480

falconensis............... ...-....------- 479

laeoigatus.------------------------........ 480

praeouoideus............................ 479,480

praevoideus............................... 479

rear.. - 479

cf. X. rex........................... 457,459,479

validut..... .......................... 457,479

cf. X. validus...... .-.... 457,458,460,479

validus falconensis....................... 463,479

hysterus... ......_. 462,479,480, pis. 73,74

validus...........------------.- - 479

validus?..... ..................... 462,479

sp... 479

xenicus, Faunus...... . 454,455,469,470, pi. 69

Yoldiamartyria... ......................... 495

perprotracta................. ............ 495

Z

zapatolensis, Anadara......................... 506

zonata, Engina.___ 477

zorritosensis, Anadara............ ........... 511

zuliana, Anadara............................. 606

maracaibensis, Anadara................... 506

PLATES 67-82

[Contact photographs of the plates In this report are available, at cost, from U.S. Geological Survey Library, Federal Center,

Denver, Colorado 80225]
PLATE 67

[All specimens from loc. 23b]

FIGURES 1, 2, 6-8, 11, 12. Nerita hadra Woodring, n. sp. (p. 466).

1, 2. Height 5.5 mm, diameter 7 mm. USNM 646648.

6. 11, 12. Type. Height 8 mm, diameter (not quite complete) 

10.5 mm. USNM 646647.

7. 8. Height 5.8 mm, diameter 7.5 mm. USNM 646649. 

3-5, 9, 10, 14, 15. Neritina ectypha Woodring, n. sp. (p. 467).

3,4. Height 5.3 mm, diameter (incomplete) 4.8 mm. USNM

646651. 

5, 10. Height 6.3 mm, diameter (incomplete) 7 mm. USNM

646652.

9. Operculum originally in place in aperture of shell shown in 

figs. 3,4. Length 2.9 mm, width 1.7 mm. USNM 646651.

14, 15. Type. Height 6.4 mm, diameter 7.1 mm. USNM

646650. 

13, 16-18. Globularia (Globularia) megista Woodring, n. sp. (p. 475).

13, 16, 18. Type. Height (incomplete) 68 mm, diameter (incomplete) 57 mm. USNM 646682.

17. Immature. Height 14.8 mm, diameter 12.5 mm. USNM 

646683.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 3C6-E PLATE 67

LATE EOCENE MOLLUSKS FROM GATUNCILLO FORMATION
PLATE 68

[Specimens frgjn loc. 2&b, unless otherwise specified]

FIGURES 1-4. Charadreon leptus Woodring, n. sp. (p. 469).

1. Paratype. Height (incomplete) 8.9 mm, diameter 3.5 mm. USNM 646659.

2. Height (not quite complete) 12.9 mm, diameter 4 mm. USNM 646660.

3. Height (incomplete) 13.7 mm, diameter 3.7 mm. USNM 646661.

4. Type. Height (not quite complete) 18 mm, diameter 6.5 mm. USNM

646658. 

5, 6, 11, 12. Bayania epelys Woodring, n. sp. (p. 468).

5. 6. Type. Height (incomplete) 26.7 mm, diameter 11.3 mm. USNM 

646655.

11. Paratype. Height (not quite complete) 22.2 mm, diameter 9.8 mm. 

USNM 646657.

12. Paratype. Height (not quite complete) 23.4 mm, diameter 9.7 mm.

USNM 646656. 

7, 13, 17, 18. Exputens bostrychodes Woodring, n. sp. (p. 528).

Locality 12. 

7, 13, 17. Type, articulated specimen. Length 23.7 mm, height 20.4 mm.

USNM 646890. 

18. Paratype, articulated specimen. Length (incomplete) 30 mm. USNM

646891. 

8, 10. Tympanotonos acanthodes Woodring, n. sp. "(p. 471).

8. Paratype. Height (incomplete) 34 mm, diameter (incomplete) 17mm.

USNM 646672. 

10. Paratype. Height (incomplete) 9.6 mm, diameter (incomplete) 4.5 mm.

USNM 646673. 

9, 15, 19, 20. Hannc toma antyx Woodring, n. sp. (p. 470).

9. Protoconch and early post-protoconch whorls. Height 0.8 mm,

diameter 0.4 mm. USNM 646670. 

15. Paratype. Height (not quite complete) 41.8 mm, diameter (almost

complete) 15 mm. USNM 646668.

19. Type. Height (incomplete) 54.7 mm, diameter (almost complete) 20 

mm. USNM 646667.

20. Height (incomplete) 44.8 mm, diameter (almost complete) 16.8 mm.

USNM 646669. 

14, 16, 21. Bezanconia cosmeta Woodring, n. sp. (p. 472).

14. Paratype. Height (almost complete) 28.5 mm, diameter (incomplete)

llmm. USNM 646678. 

16. Height (incomplete) 43.2 mm, diameter (incomplete) 20 mm. USNM

646679. 

21. Type. Height (incomplete) 41 mm, diameter (incomplete) 17mm.

USNM 646677. 

22, 23. Leptomurex acares Woodring, n. sp. (p. 476).

Type. Height 11.3 mm, diameter 6.8 mm. USNM 646684.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 68

X5

22 

LATE EOCENE MOLLUSKS FROM GATUNCILLO FORMATION

23

475-796 O - 73 - 7
PLATE 69

[Specimens from loc. 23b, unless otherwise specified]

FIGURES 1, 2, 10. Calyptraea lispa Woodring, n. sp. (p. 473).

1. Paratype. Height 2.3 mm, maximum diameter 5.5 mm. USNM 

646681.

2. 10. Type. Height 10.5 mm, maximum diameter 19.2 mm. USNM

646680. 

3, 5-8. Harrisianella camptica Woodring, n. sp. (p. 472).

3. Paratype. Height (incomplete) 14.5 mm, diameter (almost complete) 

6.5 mm. USNM 646675.

5, 6. Type. Height (almost complete) 31.6 mm, diameter (almost complete) 10 mm. USNM 646674.

7, 8. Height (incomplete) 15 mm, diameter (almost complete) 9 mm.

USNM 646676. 

4, 15, 16. Potamides? micraulax Woodring, n. sp. (p. 470).

4. Paratype. Height (not quite complete) 18.9 mm, diameter (incomplete) 7.2 mm. USNM 646666.

15. Type. Height (incomplete) 20 mm, diameter (incomplete) 10.2 

mm. USNM 646664.

16. Paratype. Height (not quite complete) 27 mm, diameter (incomplete) 9.8 mm. USNM 646665. 

9. Leptadrillia? n. sp. (p. 481).

Height (incomplete) 22.5 mm, diameter (almost complete) 9.7 mm.

USNM 646686. 

11, 12, 17. Nerita listrota Woodring, n. sp. (p. 466).

Type. Height 15 mm, diameter 19 mm. USNM646646. 

13, 14, 19. Faunus xenicus Woodring n. sp. (p. 470).

13, 14. Type. Height (incomplete), 37.5 mm, diameter (incomplete)

18 mm. USNM 646662.

19. Paratype. Height (not quite complete) 41.5 mm, diameter (incomplete) 14.5 mm. USNM 646663.

18. Glycymeris (Glycymeris) cf. G. caracoli Anderson (p. 519). 

Length 25 mm, height 25.3 Locality 12. USNM 646851. 

20. Atrina sp. (p, 525).

Length (incomplete) 33 mm, height 26 mm. Locality 32. USNM 646889. 

21, 22. Neritina sp. (p. 467).

Height 10.2 mm, diameter 10.9 mm. USNM 646653. 

23, 24. Tympanotonos acanthodes Woodring, n. sp. (p. 471)

Type. Height (incomplete) 36.5 mm, diameter (including spines) 27.5 

mm. USNM 646671.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE

21 22 23 

LATE EOCENE MOLLUSKS PROM GATUNCILLO FORMATION

24
PLATE 70

FIGURES 1, 2, 6, 13. Anadara (Rasia) lita Woodring, n. sp. (p. 504). 

Locality 42d. Bohio formation.

1. 6. Type. Length (not quite complete) 18 mm, height 14.2 mm. 

USNM 646695.

2. Length 9 mm, height 7mm. USNM 646696. 

13. Paratype. Length 13.7 mm, height 10.5 mm. USNM 646854. 

3, 9, 10. Teinostoma (Idioraphe) elachistum Woodring, n. sp. (p. 467).

Type. Height 0.6 mm, diameter 1.3 mm. Locality 23b. Gatuncillo 

formation. USNM 646654.

4. Acila (Acila) isthmica isthmica (Brown and Pilsbry) (p. 489).

Length 15.5 mm, height 12.3 mm. Locality 541. Caimito formation. 

USNM 646702.

5. Anadara (Rasia) carmenensis Clark (p. 500).

Length 6.5 mm, height 3.5 mm. Locality 41b. Marine member of

Bohio (?) formation. USNM 646692. 

7. Cadulus (Gadilopsis) dolichus Woodring, n. sp. (p. 486).

Type. Length 11.8 mm, maximum diameter 1.2 mm, apical diameter 

0.9 mm. Locality 41b. Marine member of Bohio (?) formation. 

USNM 646689. 

8, 15, 16. Saccella phlyctaena Woodring, n. sp. (p. 491).

Marine member of Bohio (?) formation. 

8, 16. Type. Length 11 mm, height 6.5 mm. Locality 40d. USNM

646690.

15. Length 9.7 mm, height 5.5 mm. Locality 41b. USNM 646691. 

11, 12. Nucula (Nucula) cf. N. spheniopsis Conrad (p. 488). 

Caimito formation.

11. Length 3 mm, height 3 mm. Locality 54n. USNM 646701.

12. Length 4.3 mm, height 4 mm. Locality 54h. USNM 646700. 

14. Portlandia (Portlandella?) euthynta Woodring, n. sp. (p. 495).

Type. Length 13 mm, height 7.2 mm. Locality 42i. Bohio formation.

USNM 646694. 

17. Adrana stena Woodring, n. sp. (p. 493).

Type. Length (not quite complete) 48.5 mm, height 11.4 mm. Locality

42d. Bohio formation. USNM 646693. 

18-22. Samanoetia samanensis (Olsson) (p. 517).

Marine member of Bohio (?) formation.

18. Length 20.2 mm, height 19.5 mm. Locality 42a. USNM 646853.

19. 20. Length 22 mm, height 18.5 mm. Locality 42a. USNM 646887.

21. Length 19 mm. height 17.2 mm. Locality 41b. USNM 646852.

22. Length (not quite complete) 25.8 mm, height 21 mm. Locality

40b. USNM 135225. 

23-25. Volvariella? sp. (p. 481).

Marine member of Bohio (?) formation.

23. Height (almost complete) 21.8 mm, diameter 7.5 mm. Locality 

41. USNM 646687.

24. 25. Height (almost complete) 6.9 mm, diameter 2.6 mm. Locality

41b. USNM 646688. 

26, 27. Cymia (Tritonopsis) n. sp. (p. 477).

Height (incomplete) 13.5 mm, diameter 10.3 mm. Locality 23b. 

Gatuncillo formation. USNM 646685.
GEOLOGICAL SURVEY 

J'^

PROFESSIONAL PAPER 306-E PLATE 70

: iilKMj^ 

.ft-jGOTj/ilr - J 1 -A'- ,4

LATE EOCENE MOLLUSKS FROM GATUNCILLO FORMATION AND MARINE MEMBER 

OF BOHIO(?) FORMATION, AND LATE OLIGOCENE MOLLUSKS 

FROM BOHIO AND CAIMITO FORMATIONS
PLATE 71

FIGUKE 1. Anadara (Rasia) dariensis progonica Woodring, n. subsp. (p. 500).

Type. Length 24.6 mm, height 14.9 mm. Locality 112. Culebra formation.

USNM 646705. 

2, 3. Saccella cf. S. subcerata (Woodring) (p. 492).

Length 7 mm, height 4 mm. Locality 54k. Caimito formation. USNM 646704. 

4, 5, 10, 11. Architectonica (Architectonica) nobilis Roding, subsp. (p. 473).

Locality lOlh. La Boca formation.

4, 5, 11. Height 6.5 mm, diameter 13.5 mm. USNM 646709. 

10. Height (reduced by crushing) 8.5 mm, diameter 30.5 mm. USNM 646710. 

6, 7, 16. Dentalium (Fissidentalium) uscarianum Olsson (p. 483). 

Locality 54k. Caimito formation.

6. Apical end of specimen shown in fig. 7.

7. Length (incomplete at anterior end) 13.6 mm, anterior diameter 2.7 mm,

apical diameter 0.9 mm. USNM 646699. 

16. Length (incomplete at both ends) 52 mm, anterior diameter 7.3 mm,

apical diameter 2.7 mm. USNM 646698.

8, 17. Dentalium (Dentalium) armillatum proterum Woodring, n. subsp. (p. 482). 

8. Apical end of specimen shown in fig. 17.

17. Type. Length (incomplete at both ends) 40.2 mm, anterior diameter 3.5 

mm, apical diameter 1.3 mm. Locality 54h. Caimito formation. USNM 

646697. 

9, 12-14. Semicassis (Echinophoria) tostoma Woodring, n. sp. (p. 476).

Locality lOlh. La Boca formation. 

9, 12, Paratype. Height (almost complete) 20.7 mm, diameter (terminal

varix missing) 16.8 mm. USNM 646714. 

13, 14. Type. Height (incomplete) 28 mm, diameter (terminal varix missing)

23.5 mm. USNM 646713. 

15. Acila (Acila) isthmica isthmica (Brown and Pilsbry) (p. 489).

Length 24 mm, height 17 mm. Locality lOli. La Boca formation. USNM

646715. 

18. Turritella collazica Maury (p. 467).

Height (incomplete) 35 mm, diameter 23 mm. Locality 116a. La Boca formation. USNM 646707. 

19,20. Isognomon (Mimoniori) mimeticus Woodring, n. sp. (p. 527).

Type. Height 49 mm, width 25 mm. Locality 116a. La Boca formation. 

USNM 646893.
PROFESSIONAL PAPER 306-E PLATE 71

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PLATE 72

FIGUKE 1. Glycymeris (Tucelona) secticostata schencki Nicol (p. 521).

Length 20.3 mm, height 19.9 mm. Locality 116a. La Boca formation. USNM 

646862.

2. Anadara (Potiarca) aff. A. chavezi (Engerrand and Urbina) (p. 514).

Length 18 mm, height about 17 mm. Locality 116. La Boca formation. USNM 

646861.

3. Modiolus americanus (Leach)? (p. 523).

Length 25.6 mm, height 15 mm. Locality 94. La Boca formation USNM

646888. 

4, 6, 8. Anadara (Rasia) athroa Woodring, n. sp. (p. 505).

4. Length 29.3 mm, height 20 mm. Locality 116. La Boca formation. USNM

646717. 

6. Length 16 mm, height 8.4 mm. Locality 116a. La Boca formation. USNM

646718. 

8. Type. Length 37.9 mm, height 26.5 mm. Locality 116a. La Boca formation.

USNM 646716. 

5, 9. Jupiteria aipeia Woodring, n. sp. (p. 490).

Type. Length 8.6 mm, height 6.2 mm. Locality 54h. Caimito formation.

USNM 646703. 

7. Brachidontes sp. (p. 523).

Length (not quite complete) 27.5 mm, height 16 mm. Locality 99f. La Boca

formation. USNM 646863. 

10, 11, 15. Anadara (Grandiarca) balboai (Sheldon) (p. 510).

10, 11. Articulated specimen. Length 21.9 mm, height 18 ujn. Locality 116a.

La Boca formation. USNM 646860. 

15. Length 38 mm, height 29.5 mm. Locality 108c. Culebra formation. USNM

646857. 

12, 16, 19. Trochita sp. (p. 474).

Height 12.5 mm, diameter 23.3 mm. Locality 116a. La Boca formation. USNM

646711. 

13, 14. Cyphoma aff. C. intermedia (Sowerby) (p. 475).

Height (almost complete) 41 mm, diameter 20.3 mm. Locality lOlh. La Boca

formation. USNM 646712. 

17, 18. Anadara (Grandiarca) chiriquiensis chiriquiensis (Gabb) (p. 508).

17. Length 42.2 mm, height 37.6 mm. Locality 110. Culebra formation. USNM 

646856.

18. Length 42.3 mm, height 36.5 mm. Locality 103. Culebra formation. USNM 

646855.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 72

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18

LATE OLIGOCENE MOLLUSKS FROM CAIMITO FORMATION, AND EARLY 

MIOCENE MOLLUSKS FROM CULEBRA AND LA BOCA FORMATIONS
PLATE 73

FIGURES 1, 4. Mytilus canoasensis vidali Ferreira and Cunha (p. 522).

1. Length 49.2 mm, height 23.7 mm. Locality 106. Culebra formation.

USNM 646859. 

4. Length 77 mm, height 34.7 mm. Locality 106. Culebra formation.

USNM 646858.

2. Area imbricata Bruguiere (p. 496).

Length 27.7 mm, height 16.5 mm. Locality 76. Alhajuela formation. 

USNM 646720.

3. Anadara (Tosarca) cf. A. tectumcolumbae (Maury) (p. 507).

Latex cast. Length 36.5 mm, height (not quite complete) 25.5 mm.

Locality 85a. Alhajuela formation. USNM 646721. 

5, 6. Nerita (Neritaf) sp. (p. 466).

Height 10.5 mm, diameter 11.2 mm. Locality 116a. La Boca formation. 

USNM 646706.

7. Crucibulum (Crucibulum) spinosum (Sowerby) (p. 474).

Height 9.7 mm, diameter 15.2 mm. Locality 138c. Lower part of Gatun 

formation. USNM 646722.

8. Anadara (Tosarca) campta Woodring, n. sp. (p. 506).

Type. Length (practically complete) 34.6 mm, height 28 mm. Locality lOlh. 

La Boca formation. USNM 646719.

9. Pteria inornata (Gabb)? (p. 526).

Length (incomplete) 24.5 mm, height (incomplete) 23.5 mm. Locality 114. 

La Boca formation. USNM 646892.

10. ~Kancus validus hysterus Woodring, n. subsp. (p. 479).

Immature paratype. Height (incomplete) 77 mm, diameter 45 mm. Locality 

159b. Middle part of Gatun formation. USNM 646727.

11. Melongena cf. M. propatula Anderson (p. 478).

Height (almost complete) 81.5 mm, diameter (not including spines) 49

mm. Locality 138f. Lower part of Gatun formation. USNM 646725. 

12, 13. Xancid?, genus? (p. 480).

Height (incomplete) 36 mm, diameter (including knobs) 39.7 mm. Locality 

138c. Lower part of Gatun formation. USNM 646728.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 73

m

EARLY MIOCENE MOLLUSKS FROM CULEBRA, LA BOCA, AND ALHAJUELA 

FORMATIONS, AND MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 74

FIGUEE 1. Turritella subgrundifera Dall (p. 468).

Height 32.2 mm, diameter 13.6 mm. Locality lOlh. La Boca formation. USNM

646708. 

2, 3. Xancus validus hysterus Woodring, n. subsp. (p. 479).

Slightly reduced. Type. Height (incomplete) 265 mm, diameter 110 mm.

Locality 159b. Middle part of Gatun formation. USNM 646726. 

4, 5. Engina turbinella (Kiener) (p. 477).

Height (not quite complete) 10.9 mm, diameter 7 mm. Locality 138f. Lower 

part of Gatun formation. USNM 646723.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 74

EARLY MIOCENE MOLLUSK FROM LA BOCA FORMATION AND 

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 75

FIGURES 1, 2. Cadulus (Platyschides) epetrion Woodring, n. sp. (p. 487). 

Locality 139c. Middle part of Gatun formation.

1. Type. Length 8 mm, miximum diameter 1.3 mm, apertural diameter 1 mm, apical diameter 0.4 mm. USNM 

646741.

2. Paratype. Length 7 mm, maximum diameter 1.2 mm, apertural diameter 0.9 mm, apical diameter 0.3 mm.

USNM 646732. 

3, 4. Cadulus (Platyschides) bushii Dall (p. 487).

Locality 147b. Middlepart of Gatun formation.

3. Length 7 mm, maximum diameter 1.2 mm, apertural diameter 0.8 mm, apicald iameter 0.4 mm. USNM 646733.

4. Length 6.5 mm, maximum diameter 1.4 mm, apertural diameter 1 mm, apical diameter 0.5 mm. USNM 646734. 

5, 16, 31. Dentalium (Laevidentalium) pyrum Pilsbry and Sharp (p. 485). 

Middle part of Gatun formation.

5. 16. Length (incomplete at both ends) 13.6 mm, anterior diameter 2.1 mm, apical diameter 1.6 mm. Fig. 16

anterior end. Locality 162a. USNM 646736.

31. Apical end. Diameter at lower end of sheath 0.7 mm. Locality 162. USNM 646737. 

6, 7. Glycymeris (Tucetona) secticostata schencki Nicol (p. 521). 

Upper part of Gatun formation, eastern area.

6. Length 19 mm, height 20 mm. Locality 171 USNM 646886.

7. Topotype. Length 24.5 mm, height 23.3 mm. Locality 173. USNM 646885.

8. Nucula (Nucula) tenuisculpta Gabb (p. 488)

Length 3 mm, height 2.7 mm. Locality 177b. Upper part of Gatuii formation, eastern area. USNM 646743.

9. Nucula (Nucula) cf. N. cahuitensis Olsson (p. 488).

Length 1.7 mm, height (incomplete) 1.2 mm. Locality 139c. Middle part of Gatun formation. USNM 646742. 

10, 11. Cadulus (Gadilopsis) dentalinus (Guppy) (p. 486).

Locality 147b. Middle part of Gatun formation.

10. Height 8.4 mm, maximum diameter 1.2 mm, apertural diameter 0.7 mm; apical diameter 0.3 mm. USNM 

646740.

11. Height 5.4 mm, maximum diameter 0.9 mm, apertural diameter 0.6 mm, apical diameter 0.3 mm. USNM

646739. 

12, 13. Dentalium (Tesseracme) dissimile Guppy (p. 483).

Length (incomplete at anterior end) 4 mm, anterior diameter 0.9 mm, apical diameter 0.6 mm. Fig. 12 anterior

end. Locality 137. Lower part of Gatun formation, USNM 646731. 

14, 23. Dentalium (Dentalium) bothrum Woodring, n. sp. (p. 482).

Type. Length (incomplete at both ends) 39.5 mm, anterior diameter 8.2 mm, apical diameter 3.6 mm. Fig. 14

apical end. Locality 179. Upper part of Gatun formation, western area. USNM 646730. 

15, 24, 25. Dentalium (Dentalium) armillatum armillatum Toula (p. 482).

Length (incomplete at both ends) 40.4 mm, anterior diameter 3.9 mm, apical diameter 1.6 mm. Fig. 15 apical

end: fig. 25, anterior end. Locality 177b. Upper part of Gatun formation, eastern area. USNM 646729. 

17, 22. Jupiteria subtumida (Woodring)? (p. 491).

Length 3.4 mm, height 2.4 mm. Locality 177c. Upper part of Gatun formation, eastern area. USNM 646746. 

18-21, 27, 29, 30. Saccella acrita epacra Woodring, n. subsp. (p. 492).

18. 20. Articulated specimen. Length 6 mm, height 3.6. Locality 139c. Middle part of Gatun formation. USNM

646748.

19. 21. Type, articulated specimen. Length 5.6 mm, height 3.1 mm. Locality 147g. Middle part of Gatun formation. USNM 646747. 

27, 29. Length 6.1 mm, height 3.7 mm. Locality 185. Upper part of Gatun formation, western area. USNM

646749.

30. Length 6.6 mm, height 3.9 mm. Locality 138c. Lower part of Gatun formation, USNM 646750. 

26. Dentalium (Episiphori) innumerable elassum Woodring, n. subsp. (p. 485).

Type. Length 5.5 mm, anterior diameter 0.6 mm, apical diameter outside pipe 0.4 mm. Locality 146. Middle

part of Gatun formation. USNM 646738 

28. Dentalium (Rhabdus?) sp. (p. 484).

Length (incomplete at anterior end, not quite complete at apical end) 3.2 mm, anterior diameter 0.8 mm, apical

diameter 0.3 mm. Locality 185. Upper part of Gatun formation, western area. USNM 646735. 

32-34. Dentalium (Fissidentalium) granadanum esmeraldiim Olsson (p. 484). 

Locality 208. Chagres sandstone.

32. Length (incomplete at both ends) 42.8 mm, anterior diameter 8.4 mm, apical diameter 3.6 mm. USNM 

646777.

33. 34. Length (incomplete at both ends) 72 mm, anterior diameter 10.3 mm, apical diameter 3.2 mm. Fig. 34 

anterior end. USNM 646776.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 75

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION AND 

LATE MIOCENE MOLLUSKS FROM CHAGRES SANDSTONE
PLATE 76

FIGURES 1-3, 6. Acila (Acila) isthmica isthmica (Brown and Pilebry) (p. 489).

Upper part of Gatun formation, western area. 

1, 2. Length 21.9 mm, height 17.5 mm. Locality 183. TJSNM 646745.

3. 6. Length 22.8 mm, height 18.5 mm. Locality 179. USNM 646744. 

4, 7, 9, 11. Anadara (Rasia) actinophora actinophora (Dall) (p. 502). 

Upper part of Gatun formation, eastern area.

4. Type. Length 47 mm, height 29 mm. Locality 177. USNM 135597. 

7, 9, 11. Articulated specimen. Length 48.8 mm, height 32.3 mm. Locality 175. USNM 646762. 

5, 8, 10. Anadara (Rasid) lienosa trochala Woodring, n. subsp. (p. 503).

Locality 175. Upper part of Gatun formation, eastern area. 

5. Paratype. Length 68.2 mm, height 39.6 mm. USNM 646764. 

8, 10. Type. Length 67.6 mm, height 38.6 mm. USNM 646763.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 76

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XI

11

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION

475-796 O - 73 -
PLATE 77

FIGURES 1, 2. Anadara (Rasia) cf. A. emarginata (Sowerby) (p. 504).

Length 20.9 mm, height 13.4 mm. Locality 184. Upper part of

Gatun formation, western area. USNM 646765. 

3, 5, 13, 18, 21, 22, 24. Anadara (Rasia) dariensis dariensis (Brown and Pilsbry) (p. 501).

3. Length 24 mm, height 13.5 mm. Locality 138f. Lower part of

Gatun formation. USNM 646761. 

5. Length 29 mm, height 17.5 mm. Locality 139c. Middle part of

Gatun formation. USNM 646760. 

13, 22, 24. Articulated specimen. Length 35.3 mm, height 22.7

mm. Locality 147h. Middle part of Gatun formation. USNM

646759. 

18. Length 41.5 mm, height 24 mm. Locality 183. Upper part of

Gatun formation, western area. USNM 646758. 

21. Length 42.3 mm, height 24.6 mm. Locality 155b. Middle part

of Gatun formation USNM 646757. 

4, 8. Acar domingensis (Lamarck) (p. 497).

Length 18 mm, height 10.2 mm. Locality 160d. Middle part of

Gatun formation. USNM 646756.

6. Anadara (Potiarca) cf. A. berjadinensis (H. K. Hodson) (p. 516).

Length 33.9 mm, height 27.8 mm. Locality 138e. Lower part of 

Gatun formation. USNM 646872.

7. Caltoarca (Taeniarca) cachla (Olsson) (p. 497).

Length (incomplete) 21.5 mm, height 12.5 mm. Locality 160.

Middle part of Gatun formation. USNM 646755. 

9, 11, 19, 20, 23. Saccelto balboae (Brown and Pilsbry) (p. 493).

9,23. Length 19.6 mm, height 11.4 mm. Locality 171. Upper

part of Gatun formation, eastern area. USNM 646752. 

11, 19,20. Length 10.7 mm, height 6.1 mm. Locality 136. Lower

part of Gatun formation. USNM 646753. 

10, 16. Saccella cf. S. fabalis (Olsson) (p. 493).

Length 5.2 mm, height 2.5 mm. Locality 169. Middle part of

Gatun formation. USNM 646751. 

12. Anadara (Cunearca) eumeces Woodring, n. sp. (p. 516).

Type. Length 20.5 mm, height 17 mm. Locality 138c. Lower part 

of Gatun formation. USNM 646873. 

14, 15. Bailya crossata Woodring, n. sp. (p. 478).

Type. Height 16.9 mm, diameter 7.5 mm. Locality 138e. Lower

part of Gatun formation. USNM 646724. 

17. Area imbricata Bruguiere (p. 496).

Length 16.4 mm, height 9.9 mm. Locality 138e. Lower part of 

Gatun formation. USNM 646754
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 77

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 78

FIGURES 1-6. Anadara (Rasid) fissicosta (Spieker) (p. 505).

1, 3. Length 36.6 mm, height (not quite complete) 29 mm. Locality 138c.

Lower part of Gatun formation. USNM 646772. 

4-6. Articulated specimen. Length 29.5 mm, height 23.8 mm. Locality 136.

Lower part of Gatun formation. USNM 646771. 

2. Length 22.6 mm, height 16.5 mm. Locality 139c. Middle part of Gatun

formation. USNM 646773. 

7-11. Anadara (Tosarca) veatchi veatchi (Olsson) (p. 507).

7, 8, 11. Articulated specimen. Length 46.6 mm, height 44.7 mm. Locality

183. Upper part of Gatun formation, western area. USNM 646775.

9. Length 54.5 mm, height 49.2 mm. Locality 155. Middle part of Gatun 

formation. USNM 646774.

10. Length 47.8 mm, height 44.9 mm. Locality 182a. Upper part of Gatun 

formation, western area. USNM 646905.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 78

*^^

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 79

FIGURES 1-6, 8. Anadara (Rasia) sechurana (Olsson) (p. 505).

Locality 138c. Lower part of Gatun formation. 

1, 2. Length 33 mm, height 27.2 mm. USNM 646766.

3. 6. Length 35.8 mm, height 27.6 mm. USNM 646767.

4. Length 31.2 mm, height 25.7 mm. USNM 646770.

5. Length 27.2 mm, height 19.4 mm. USNM 646768. 

8. Length 26.6 mm, height 23.2 mm. USNM 646769. 

7, 11. Lunarca ovalis (Bruguiere)? (p. 516).

Length 23.7 mm, height 20.9 mm. Locality 160d. Middle part of Gatun

formation. USNM 646874. 

9, 10. Glycymeris (Glycymeris) carbasina Brown and Pilsbry (p. 519).

Immature. Length 19.2 mm, height 17.2 mm. Locality 172. Upper part of

Gatun formation, eastern area. USNM 646879. 

12, 13. Anadara (Grandiarca) grandis patricia (Sowerby)? (p. 512).

Length (incomplete) 88.5 mm, height (incomplete) 67.5 mm. Locality 170. 

Middle part of Gatun formation. USNM 646866.
GEOLOGICAL SURVEY

PROFESSIONAL PAPER 306-E PLATE 79

Xl%

* " :11%

XI

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 80

FIGURE 1. Isognomon (Melina?) sp. (p. 527).

Height (incomplete) 29 mm, width (incomplete) 37.5 mm. Locality 170.

Middle part of Gatun formation. USNM 646901. 

2, 3. Crenella ecuadoriana Santiago, Olsson (p. 524).

Length 2.3 mm, height 3 mm. Locality 170a. Middle part of Gatun formation.

USNM 646895. 

4, 5. Pteria inornata Gabb? (p. 526).

4. Length (incomplete) 28 mm, height 24 mm. Locality 147g. Middle part of 

Gatun formation. USNM 646899.

5. Length (incomplete) 26 mm, height (incomplete) 20 mm. Locality 139g.

Middle part of Gatun formation. USNM 646900. 

6-9, 12. Anadara (Grandiarcd) dolaticosta (Pilsbry and Johnson) (p. 510).

6. 9. Length (incomplete) 48 mm, height (incomplete) 49.2 mm. Locality 170. 

Middle part of Gatun formation. USNM 646864.

7. 8, 12. Length 45 mm, height 45.8 mm. USGS 8010, Quebrada Schawb,

Costa Rica. Deposits of middle Miocene age. USNM 646865. 

10, 11. Crenella divaricata (d'Orbigny) (p. 524).

Length 1.6 mm, height 2.1 mm. Locality 159d. Middle part of Gatun formation. USNM 646894.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 80

t M V'l In';* !>n«,*

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION AND COSTA RICA
PLATE 81

FIGUBES 1-3, 6. Anadara (Potiarcd) chavezi (Engerrand and Urbina) (p. 514).

1. Length 30.5 mm, height 26.4 mm. Locality 159d. Middle part of 

Gatun formatiou. USNM 646870.

2. Length 18.8 mm, height 17.4 mm. Locality 138c. Lower part of Gatun 

formation. USNM 646868.

3. Length 24.5 mm, height 27 mm. Locality 159d. Middle part of Gatun

formation. USNM 646871. 

6. Length 14.5 mm, height 13.7 mm. Locality 138c. Lower part of Gatun

formation. USNM 646869.

4, 5, 8. Glycymeris (Tucetona) pectinata canalis Brown and Pilsbry (p. 520). 

Middle part of Gatun formation, eastern area.

4. Length 34.6 mm, height 36 mm. Locality 155a. USNM 646882.

5. Length 24.4 mm, height 25.4 mm. Locality 155a. USNM 646884. 

8. Length 35 mm, height 35 mm. Locality 155b. USNM 646883. 

7, 11. Glycymeris (Tucetona) epacra Woodring, n. sp. (p. 520).

Upper part of Gatun formation, western area. 

7. Length 24.8 mm, height 25 mm. Locality 182. USNM 646881. 

11. Type. Length 33.7 mm, height 36.2 mm. Locality 182a. USNM

646880. 

9, 10. Glycymeris (Glycymeris) carbasina Brown and Pilsbry (p. 519).

Length 42.7 mm, height 40.5 mm. Locality 155. Middle part of Gatun

formation. USNM 646878. 

12, 13. Noetia (Noetia) reversa macdonaldi (Dall) (p. 518).

Length 46.5 mm, height 37.7 mm. Locality 138a. Lower part of Gatun 

formation. USNM 646875.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 81

12 13 

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION
PLATE 82

FIGURES 1, 4. Noetia (Noetia) reversa macdonaldi (Dall) (p. 518). 

Middle part of Gatun formation, eastern area.

1. Length 36.4 mm, height 27.3 mm. Locality 155a. USNM 646877. 

4. Length 35.7 mm, height 30 mm. Locality 155. USNM 646876. 

2. Acila (Acila) isthmica isthmica (Brown and Pilsbry) (p. 489).

Length 21.9 mm, height 17 mm. Locality 208. Chagres sandstone. USNM

646778. 

3, 6-8. Anadara (.Basra) honensis adiaphora Woodring, n. subsp. (p. 502).

Locality 208. Chagres sandstone. 

3. Length 46.7 mm, height 32.2 mm. USNM 646780. 

6, 7. Type. Length 52.5 mm, height 35.2 mm. USNM 646779.

8. Length 30.2 mm, height 21.5 mm. USNM 646906. 

5. Anadara (Potiarca) chavezi (Engerrand and Urbina) (p. 514).

Length 23.2 mm, height 20 mm. Locality 137. Lower part of Gatun formation. USNM 646867.

9-11. Atrina (Servatrina) aff. A. serrata (Sowerby) (p. 525). 

Locality 139g. Middle part of Gatun formation.

9. Length (incomplete) 64.5 mm, height 25 mm. USNM 646896.

10. Ventral fragment. Length (incomplete) 40 mm, height (incomplete) 

20 mm. USNM 646898.

11. Length (incomplete) 60 mm, height 23 mm. USNM 646897.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 306-E PLATE 82

X 1

MIDDLE MIOCENE MOLLUSKS FROM GATUN FORMATION AND 

LATE MIOCENE MOLLUSKS FROM CHAGRES SANDSTONE

U. S. GOVERNMENT PRINTING OFFICE : 1973 O - 475-796