Early and Middle 

Cambrian Trilobites 

From Antarctica

GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D
Early and Middle 

Cambrian Trilobites 

From Antarctica

By ALLISON R. PALMER and COLIN G. GATEHOUSE 

CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D

Bio stratigraphy and regional significance of 

nine trilobite faunules from Antarctic outcrops 

and moraines; 28 species representing 21 

genera are described

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1972
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

V. E. McKelvey, Director

Library of Congress catalog-card No. 73-190734

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

Washington, D.C. 20402 - Price 70 cents (paper cover)

Stock Number 2401-2071
CONTENTS

Abstract_ _ ________________________

I&troduction. _______________________

Biostratigraphy _____________________

Early Cambrian faunules.________

Australaspis magnus faunule_ 

Chorbusulina wilkesi faunule _ _ 

Chorbusulina subdita faunule _ _

Early Middle Cambrian f aunules __ 

Xystridura mutilinia faunule- _ 

Xystridura glacia faunule _____

Late Middle Cambrian faunules-__ 

Amphoton oatesi faunule ______

Schopfaspis granulosus faunule. 

Solenopleura pruina faunule___ 

Nelsonia schesis faunule_______

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4

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5

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5

5

5

5

5

6

Page

Physical stratigraphy______________________________ D6

Regional correlation within Antarctica ________________ 7

Systematic paleontology._____-_______-____-_-_-----_ 9

Summary of classification of Antarctic Early and

Middle Cambrian trilobites. ___________________ 9

Agnostida__ _ _________-____-_--____-----__---_ 9

Redlichiida. __-_--------------------------_---- 12

Corynexochida._________--________-_-_---_----_ 17

Ptychopariida._________________________________ 21

Unassigned trilobites_-__---_-_--_-___-----__. ___ 26

Collecting localities and f aunal lists ___________________ 32

References cited-___________________________________ 33

Index._______________________________-_-------_--- 37

ILLUSTBATIONS

[Plates 1-6 follow index]

PLATE 1. Early Cambrian Australaspis magnus and Chorbusulina wilkesi f aunules.

2. Early Cambrian Chorbusulina wilkesi and C. subdita faunules and early Middle Cambrian Xystridura multilinia 

faunule.

3. Early Middle Cambrian Xystridura multilinia and -X". glacia faunules and late Middle Cambrian Amphoton oatesi 

faunule.

4. Late Middle Cambrian Amphoton oatesi and Schopfaspis granulosus faunules.

5. Late Middle Cambrian Schopfaspis granulosus and Solenopleura pruina faunules.

6. Late Middle Cambrian Solenopleura pruina and Nelsonia schesis faunules and an unassigned faunule.

FIGURE 1. Index map of part of Antarctica showing localities mentioned in this report-__--_________---_--__-_-__-__---

2. Correlation chart showing biostratigraphic units mentioned in text and the approximate position of the Antarctic 

trilobite faunules______-______________________________-____________-_-__-__-_-_--_---_---_---------

3. Correlation chart suggesting possible relations of the Cambrian rock units of Antarctica______________________

m

Page 

D2

CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM

ANTARCTICA

By ALLISON R. PALMER x and COLIN G. GATEHOUSE 2

ABSTRACT

Eight trilobite faunules ranging in age from Early Cambrian 

to late Middle Cambrian have been recovered from fossiliferous 

moraine boulders at Mount Spann in the northeastern Argentina 

Range, Antarctica. One of the late Middle Cambrian faunules 

from Mount Spann and one additional Middle Cambrian faunule 

were collected in place in the lowermost part of the Nelson 

Limestone of the Neptune Range. Badly deformed and slightly 

metamorphosed Middle Cambrian trilobites from the Harold 

Byrd Mountains represent a probable tenth faunule. Almost 

all trilobites in these faunules are close relatives of Australian, 

Chinese, or Siberian forms. There are no significant relations 

between any of the faunules and the Cambrian trilobites of South 

or North America. Within Antarctica, the areas of the Neptune 

Range and possibly also the Harold Byrd Mountains were the 

last to be inundated by transgressing Cambrian seas. Limestones 

in the Argentina Range at the Weddell Sea end of the Transantarctic Mountains, and the Shackleton Limestone at the Ross 

Sea end of the mountains, are considerably older than the 

oldest limestones in the Neptune Range.

The trilobite faunas include 28 species representing 21 genera ; 

of these, 22 species and four genera are new. New taxa are: 

Pagetla, lonyispina n. sp., Pageti&esl antarcticus n. sp., Australaspis magnus n. gen., n. sp., Xystridura glacia n. sp., X. multilinia 

n. sp., Chorbusulina subdita n. sp., C. wilkesi n. sp., Amphoton 

oatesi n. sp., Kootenia styrax n. sp., Bathyuriscellus austraMs 

n. sp., B. modestus n. sp., Goldfieldia ningws n. sp., Chondranomocare australis n. sp., Liopeishania spawnensis n. sp., Suludellal 

davnii n. sp., 8. spinosa n. sp., Trinepea trinodus n. gen., n. sp., 

Solenopleura pruina n. sp., Glabrellu'i pitans n. sp., Nelsonia 

schesis n. gen., n. sp., Pensacola isolata n. sp., Schopfaspis 

granulosus n. gen., n. sp.

INTRODUCTION

Antarctica is the last of the world's continents to be 

explored geologically. It is also a key element of the 

late Paleozoic continent of Gondwana that has been 

fragmented into the present continents of Africa, South 

America, Australia, and Antarctica during the Mesozoic 

and Cenozoic eras. Until now there has been little direct 

evidence for the early Paleozoic regional relationships

1 State University of New York, Stony Brook, N.Y.

2 Delhi International Oil Corp., Adelaide, South Australia.

of Antarctica. Although Cambrian fossils were first described from Antarctica by Gordon (1920), that report 

and all subsequent descriptive studies recorded only 

Archaeocyatha. These fossils lack sufficient provinciality 

to assist greatly in problems relating to early Paleozoic 

geography (Zhuravleva, 1968). Thus, the discovery of 

Cambrian trilobites in 1964 opened up the possibility for 

more precise evaluation of early Paleozoic geographic 

relations of Antarctica. In this paper, the problems of 

the regional Cambrian stratigraphy of Antarctica and 

its relation to the other southern continents during the 

Cambrian is explored, and all known Early and Middle 

Cambrian trilobites of Antarctica are described.

Outcropping sequences of sedimentary rocks that 

include fossiliferous Cambrian limestones are known 

from five scattered areas in Antarctica (fig. 1). Four 

of these, the Argentina Kange, the Neptune Kange, the 

Harold Byrd Mountains, and areas adjacent to the ice 

shelf in southern Victoria Land are within the Transantarctic Mountains. The fifth area, the Heritage Kange, 

is now in West Antarctica, but Schopf (1969) has suggested that it is part of a dislocated segment of the 

Transantarctic Mountains that originally was north 

of the Argentina and Neptune Ranges.

Trilobite-bearing beds were first discovered in the 

1963-64 field season in the Heritage Range (Webers, 

1965) and the Neptune Range (Schmidt and others, 

1965). The following year, trilobites were collected in 

the Harold Byrd Mountains (Minishew, 1966). Additional collections from the Neptune Range and new 

collections from the Argentina Range were obtained 

during the 1965-66 field season. Trilobites have not yet 

been found in the ice-shelf areas of southern Victoria 

Land.

Trilobites from the Argentina and Neptune Ranges 

and the Harold Byrd Mountains constitute all the 

known Early and Middle Cambrian trilobites from 

Antarctica. The only known Late Cambrian trilobite 

fauna, from the Heritage Range, is being studied sepDl
D2 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

WEDDELL SEA

75

RONNE 

SHELF

EAST 

ANTARCTICA

WEST 

ANTARCTICA

100 300 KILOMETERS 

0 200

ROSS $&%>«

ICE SHELF

ROSS SEA

FIGURE 1. Index map of part of Antarctica showing localities mentioned in this report.
EARLY AND MIDDLE CAMBRIAN TR'ILOBITES FROM ANTARCTICA D3

arately by G. F. Webers of Macalester College, St. Paul, 

Minn.

All the trilobite collections, except the one made by 

Webers from the Heritage Range, were sent to Palmer 

at the U.S. Geological Survey for identification. After 

Palmer had moved to the State University of New 

York at Stony Brook, Gatehouse was assigned these 

collections for a study that resulted in a Master's thesis. 

Thus, much of the preparation of specimens and photography, and some of the suggestions about relations 

to described faunas, are the work of Gatehouse. The 

thesis has been completely revised by Palmer, however, and expanded to include some material not covered in the thesis study. Final responsibility for all 

conclusions are his.

Valuable stratigraphic and locality data have been 

provided by D. L. Schmidt (Neptune and Argentina 

Ranges) and J. M. Schopf (Argentina Range) of the 

U.S. Geological Survey and V. H. Minishew (Harold 

Byrd Mountains) of the University of Mississippi.

The systematics in this paper have benefitted greatly 

from comments by L. I. Yegorova of the Research 

Institute of Geology, Geophysics and Mineral Resources in Novosibirsk and L. N. Repina of the Institute 

of Geology and Geophysics of the Academy of Sciences 

in Academgorodok, who examined replicas of some of 

the Antarctic trilobites.

Typing of the final manuscript, much of the photography, and help with numerous details of specimen 

numbering by Miss Janet Gardner are gratefully acknowledged and sincerely appreciated.

BIOSTRATIGRAPHY

With the exception of trilobite assemblages from the 

Neptune Range, and the deformed and generically indeterminate trilobites from the Harold Byrd Mountains, all the Early and Middle Cambrian trilobites 

from Antarctica are from morainal debris or talus. 

In this paper, assemblages of species that occur in one 

or more samples are designated as faunules, and each 

faunule is named after its commonest constituent.

All the Antarctic Cambrian trilobite faunules have 

their strongest affinities with faunas from Australia, 

China, or Siberia. There is no common biostratigraphic 

framework for these areas; each has its own local nomenclature of zones and stages. Detailed correlation of 

these local biostratigraphic sequences is still not stabilized, and one of the largest unsolved problems, which 

affects the Antarctic faunas, involves the placement of 

the boundary between the Early and Middle Cambrian.

In Siberia, the Early Cambrian has traditionally been 

divided into two stages, an older Aldan Stage and a

younger Lena Stage (fig. 2). The definitive Early 

Cambrian fossils from the Russian viewpoint are Archaeocyatha. Olenellid trilobites, which are the defintive 

elements of the Early Cambrian, as originally defined 

by Walcott (1891), are found only in the Aldan Stage. 

Opik (1968 has pointed out this inconsistency and has 

suggested that beds of Lena Age be excluded from the 

Early Cambrian epoch. However, the problem is not so 

simply solved because precise correlation at the zone 

level between the American sequences that served as the 

original basis for the Early Cambrian and zone 

sequences elsewhere in the world is not yet possible. 

Khomentovskiy and Repina (1965) proposed a revision 

of the Early Cambrian biostratigraphy of Siberia based 

on careful analysis of the excellent exposures of beds 

of this age along the Lena River at the southern margin 

of the Siberian platform. They divided the old Lena 

Stage into two parts, a lower Botoma Stage and a 

younger Lena Stage (restricted). Furthermore, Repina 

(written commun., May 8, 1970) indicates that she has 

discovered in Siberia trilobites suggestive of forms from 

American lower Middle Cambrian beds in association 

with trilobites typical of beds of restricted Lena Age. 

Thus, Opik's views seem to be in part substantiated, but 

a consistent position for the Early Cambrian-Middle 

Cambrian boundary in all Cambrian sequences is not yet 

possible. Thus, throughout this paper, the primary age 

assignment for each faunule is in terms of the geographic 

area with which it has its greatest affinities.

Description of the position of faunules within the 

Lower Cambrian Series in general terms presents no 

major problems. However, the general positioning of 

the Middle Cambrian faunules may lead to some confusion. Most generalizations about the placement of 

faunas within the Middle Cambrian of Asia and Australia are best phrased in terms of a twofold division 

into early Middle Cambrian (Amga, pre-Taitzu and 

correlative beds) and late Middle Cambrian (Maya, 

Taitzu and correlative beds) (fig. 2). In northwestern 

Europe and North America, a threefold division into 

early, middle and late Middle Cambrian is generally 

used. Because the Antarctic Middle Cambrian faunas 

have their greatest affinities with Asia and Australia, 

their relative placement is phrased in this paper in terms 

of the twofold subdivision.

Figure 2 shows the approximate correlation of most 

of the biostratigraphic units mentioned in the discussions relating to the age of each faunule.

The nine faunules that have been recognized in Antarctica represent four age groups. The relative ages 

of each group of two or more faunules can be established 

with reasonable confidence (fig. 2), but the relative ages
CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

MIDDLE CAMBRIAN

z

o

SIBERIA

MAYA 

STAGE

AMGA 

STAGE

LENA

STAGE BOTOMA 

STAGE

ALDAN 

STAGE

AUSTRALIA

TEMPLETONIAN 

STAGE

OROIAN 

STAGE

CHINA

TAITZU 

STAGE

SWEDEN

Paradoxidts 

forchammtri 

STAGE

Paradoxidts 

p aradoxissimus 

STAGE

Paradoxides 

oelandicus 

STAGE

'Wit,

UNITED 

STATES

Bolaspidella 

ZONE

APPROXIMATE AGES 

OF 

ANTARCTIC TRILOBITE FAUNULES

I

Nelsonia schesis 

Solenopleura pruina

\ Schopfaspis granulosus 

I Amphoton oatesi

Xystridura glacia 

Xystridura multilinia

\Chorbusulina subdita 

\ Chorbusulina wilkesi 

\ Australaspis magnus

FIGURE 2. Correlation chart showing the biostratigraphic units (stages or zones) mentioned in the text and the approximate relative positions of the Antarctic trilobite faunules.

of faunules within an age group cannot be satisfactorily 

determined from presently available evidence.

The oldest age group includes the Australaspis 

magnus, Chorbusulina wilkesi, and G. subdita faunules 

that contain predominantly Siberian elements. They 

are approximately equivalent to Early Cambrian faunas 

of Botoma (early Lena unrestricted) Age. The next 

younger group contains the Xystridura multilinia and 

X. glacia faunules which have predominantly Australian elements of either Ordian or Templetonian (early 

Middle Cambrian) age. The third group includes the 

Amphoton oatesi and Schopfaspis granulosus faunules 

whose elements have affinities to Australian, Chinese, 

and Siberian faunas of about early late Middle Cambrian age. The youngest group includes the SoUnopleura 

pruina and Nelsonia schesis faunules of probable later 

Middle Cambrian age that have some affinities to Siberian faunas.

The composition of each faunule and the evidence for 

its age within the Cambrian are given below.

EARLY CAMBRIAN FAUNULES

AUSTRALASPIS MAGNUS F AUNULE

This faunule consists of two species, Australaspis 

magnus n. sp. and G-labrellal pitans n. sp., both of which 

are moderately common in two boulders (TJSGS colln. 

5939-CO and 6311-CO) from moraines on Mount 

Spann. The age of the faunule is based on the affinities 

of both species to species from the Early Cambrian of 

Siberia.

Australaspis has many peculiar cranidial features, 

particularly the structure of the palpebral lobes, ocular 

ridges, and frontal area, in common with Bulaiaspis, 

and it is almost certainly assignable to the Early Cambrian family Neoredlichiidae. Bulaiaspis ranges from 

the Tolbachan and Kameshkov horizons of late Aldan 

Age into the Uritsk horizon at the base of the Botoma 

(or Lena unrestricted) Stage.

G-la~brellal. pitans is certainly congeneric with G. mrassina Yegorova from the Obruchev horizon of Lena 

Age in southern Siberia.
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D5

The position of this faunule relative to the Ghorl)usulina wilkesi faunule is not determinable from presently available evidence.

CHORBUSULINA WILKESI FAUNULE

This faunule includes four species of trilobites, 

Bathyuriscellus australis n. sp., Ohorbusulina wilkesi 

n. sp., Pensacola isolata n. gen., n. sp., and Redlichia 

sp. undet., and an undetermined archaeocyathid. All 

the species were found associated in a single boulder 

(TJSGS colln. 6308-CO) at Mount Spann. Four other 

boulders in the same area had at least two of the trilobite species. The commonest species, both in numbers 

of individuals and frequency of occurrence are P. isolata 

and C. wilkesi. Determination of the age of the faunule 

is based on comparison with the Cambrian faunas of 

Siberia. Redlichia is reported only from the Olekminsk 

and Sanashtykgol horizons of the Botoma or early Lena 

(unrestricted) Stages (Repina, 1966) of the Siberian 

Early Cambrian. Bathyuriscellus ranges from the uppermost part of the Aldan Stage (Lazarenko, 1964) to 

the Angarsk horizon of the post-Botoma part of the 

Lena Stage (unrestricted) (Chernysheva, 1961) of the 

Siberian Early Cambrian but is most common in the 

intervening Olekminsk and Sanashtykgol horizons 

(Repina and others, 1964; Suvorova, 1960b). Ghorbusulina is reported only from the Judomia zone of the late 

Aldan Stage (Lazarenko, 1962; Lazarenko, 1964; 

Yegorova and Savitskiy, 1969). Thus, the most likely 

correlation of the C, wilkesi faunule is with latest Aldan 

or earliest post-Aldan (Lena, unrestricted, or Botoma) 

beds in Siberia.

CHORBUSULINA SUBDITA FAUNULE 

This faunule includes two species of trilobites, Ghorbusulina subdita n. sp. and Bathyuriscellus modestus 

n. sp., that are associated in one boulder. A second 

boulder at Mount Spann containing only G. subdita 

n. sp. is also considered to be representative of this 

fauna. Very little time difference probably exists between the Chorbusulina wilkesi and C. subdita f aunules, 

and the suggested correlation for the G. wilkesi faunule 

is also valid for the C. subdita faunule.

EARLY MIDDLE CAMBRIAN FAUNULES

XYSTRIDURA MULTILINIA FAUNULE 

This faunule includes four species of trilobites and 

several species of stenothecoidid, hyolithid, and helcionellid mollusks associated in a coquina from one boulder (USGS, colln. 6333-CO) in the moraines on Mount 

Spann. The trilobites include Xystridura multilinia n. 

sp., Pagetia longispina n. sp., Goldfieldia ninguis n. sp.,

and an undetermined ptychoparioid designated as 

"Genus and species undetermined 1."

Neither Pagetia, which is a genus ranging from Early 

to medial Middle Cambrian in age, nor Goldfieldia, a 

member of the long-ranging Oryctocephalidae that has 

been found previously at only one locality in Lower 

Cambrian beds in Western United States, contribute 

much to the problem of the age of the X. multilinia 

faunule.

Xystridura, however, is a genus found principally in 

beds dated as early Middle Cambrian in Australia and 

assigned to either the Ordian or overlying Templetonian Stages (Opik, 1968). The absence of species of Red 

lichia in the Antarctic faunule, a genus associated with 

Xystridura in beds of Ordian Age, suggests that the X. 

multilinia faunule may come from beds correlative with 

the Templetonian Stage. However, precise correlation 

of the faunule must await description of more of the 

Ordian and Templetonian trilobite faunas of Australia.

XYSTRIDURA GLACIA FAUNULE

This faunule consists only of the nominal species 

which occurs in a single boulder (USGS colln. 5938- 

CO) from the moraines on Mount Spann. X. glacia is 

distinct from all described species and is not associated 

with other trilobites. The genus is found in Australia in 

beds assigned by Opik (1968) to either the Ordian or 

Templetonian Stages of early Middle Cambrian age. 

Until X. glacia is found in context with elements of 

either of these stages, its age cannot be stated more precisely than early middle Cambrian.

LATE MIDDLE CAMBRIAN FAUNULES

AMPHOTON OATESI FAUNULE

This faunule, from USGS colln. 4446-CO in the lower 

part of the Nelson Limestone in the Neptune Range, is 

characterized by six trilobites: Amphoton oatesi n. sp., 

Chondranomocare australis n. sp., Trinepea trinodus 

n. gen., n. sp., Kootenia styrax n. sp., Peronopsis cf. 

P. fallow (Linnarsson), and Genus and species undetermined 4.

Amphoton is a characteristic genus of the late Middle 

Cambrian Taitzu Stage of eastern Asia (Kobayashi, 

1967). It is also found in upper Middle Cambrian beds 

of Australia (Opik, 1961) and in beds of Amga Age 

in Siberia (Chernysheva, 1961). Chondranomocare, on 

the other hand, is found only in beds of late Amga Age 

in Siberia, which Kobayashi (1967, p. 515) correlates 

with pre-Taitzu beds of Asia. Nepeidae are characteristic 

of upper Middle Cambrian beds in Australia, and species 

of Peronopsis most similar to those from the A. oatesi 

faunule are known from upper Middle Cambrian beds 

in China, Scandinavia, and Siberia. Kootenia is a long452-253 0-72-2
D6 .CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

ranging genus of little stratigraphic value. Most of the 

elements of the A. oatesi faunule are consistent with an 

early late Middle Cambrian age.

SCHOPFASPIS GRANULOSUS FAUNULE

This faunule includes five species of trilobites: 

Schopfaspis granulosus n. sp., Pagetides^. antarcticus 

n. sp., Liopeishania spannensis n. sp., Olenoides sp., and 

Genus and species undetermined 2. Rare mollusks are 

also present. The first three species are abundantly 

represented in four boulders (USGS collns. 6313-CO, 

6325-CO, 6327-CO, and 6364-CO) from the moraine 

011 Mount Spann. Olenoides sp. and the undetermined 

ptychoparioid are rare elements in USGS colln. 

6325-CO.

Schopfaspis granulosus is a ptychoparioid trilobite 

with no close relatives that might help to identify its 

stratigraphic age.

Liopeishania spannensis n. sp. is an asaphiscid trilobite that is extremely similar to Liopeishania lubrica 

Chang (1959) from the Middle Cambrian Changhsia 

Formation of Taitzu Age in Shantung, China. Asaphiscidae are also present in the Middle Cambrian Bolaspidella zone and lower Upper Cambrian beds in North 

America. L. spannensis n. sp. shares many features with 

Asaphiscus wheeleri (Meek) from the lower part of the 

Bolaspidella zone which seems to be approximately correlative with the Taitzu Stage.

Pagetides^. antarcticus is as abundant as P.? granulosus, but pagetiids of the general aspect of this species 

which lack a terminal pygidial spine are presently 

known only from Lower Cambrian beds. The species 

differs significantly from typical species of Page-tides, 

however, in structure of the occipital spine and palpebral 

lobes.

Olenoides is a long-ranging Early to Late Cambrian 

genus.

Because the stratigraphic range of the Asaphiscidae 

is well established as late Middle Cambrian or younger 

and because Liopeishania spannensis shares so many 

features with known trilobites of this age, the age of this 

faunule is here considered to be late Middle Cambrian ; 

Pagetides ? antarcticus is considered to be a pagetiid that 

may be a derivative of Pagetia that has lost its spine and 

that only superficially resembles species of Pagetides.

SOLENOPLEURA PRUINA FAUNULE

This is a small faunule from a single boulder (USGS 

colln. 6320-CO) from the moraines on Mount Spann. 

It includes two trilobites, Solenopleura pruina 11. sp. and 

Suludella^. davnii n. sp., and fragmentary orthoid 

brachiopods. SoIenopUura is a characteristic Late Middle Cambrian genus, and the Antarctic species is most 

like species described by Chernysheva (1953) from beds

assigned to the Paradoxides forchammeri and P. davidus 

zones in eastern Siberia. Suludella is a genus characteristic of the Proasaphiscus privus zone of the middle 

part of the May a Stage in Siberia (Yegorova and 

Savitskiy, 1969). Thus, both elements in the 8. pruina 

faunule suggest a late Middle Cambrian age for the 

faunule. This faunule, with its strongest affinities to the 

late Middle Cambrian Maya Stage, is probably from 

slightly younger beds than the Amphoton oatesi faunule 

which contains some elements indicating affinity with 

the older Amga Stage.

NELSONIA SCHESIS FAUNULE

This faunule is characterized by two trilobites, Nelsonia schesis n. gen., n. sp. and Suludella? spinosa n. sp., 

and is particularly significant because it is the only 

faunule common to the outcrop areas of the Neptune 

Range (USGS colln. 4443-CO, 4445-CO, 4448-CO) and 

boulders from the moraines on Mount Spann more than 

165 miles away (USGS colln. 6355-CO).

Nelsonia schesis has no apparent close relatives, and 

the dating of the faunule depends on Suludella ? spinosa. 

This trilobite is most like species from the middle part 

of the late Middle Cambrian Maya Stage in Siberia. On 

this basis, the N. schesis faunule is tentatively dated as 

late Middle Cambrian.

PHYSICAL STRATIGRAPHY

Details are lacking for most stratigraphic sequences of 

Cambrian or possible Cambrian age in Antarctica. 

Nevertheless, enough information is now available to 

permit some regional considerations, and the stratigraphic data for each of the Cambrian areas are summarized below.

In the southern Argentina Range, the Schneider Hills 

in the south part have extensive outcrops of archaeocyathid limestone (D. L. Schmidt, written commun., 

Dec. 1966). At Mount Spann, about 40 miles to the 

northeast, moraine boulders (J. M. Schopf, written 

commun., May 1966) bear archaeocyathids, mixed 

archaeocyathids and trilobites, and trilobite-mollusk 

associations which indicate the presence of limestones 

ranging in age from Early Cambrian to late Middle 

Cambrian.

In the Neptune Range, the Cambrian sequence begins 

with the Nelson Limestone, a unit 600 to 700 feet thick, 

which lies with angular miconf ormity 011 the Patuxent 

Formation. Overlying the Nelson Limestone conformably is the Gambacorta Formation, a unit of volcanic and hypabyssal rocks more than 1,000 feet thick. 

The Wiens Formation, a unit of shale, siltstone, sandstone, and some oolitic limestone less than 1,000 feet 

thick conformably overlies the Gambacorta Formation.
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D7

All these units were deformed before deposition of the 

Elliott Sandstone (Schmidt and others, 1965).

The Nelson Limestone is the only f ossilif erous unit in 

the Neptune Range. It consists of five members: "(1) a 

basal red quartz-fragment conglomerate, 1 to 20 feet 

thick, which is composed largely of erosional detritus of 

the Patuxent Formation; (2) a local red-bed clastic 

succession which is as much as 60 feet thick; (3) a lower 

gray limestone, 200 to 300 feet thick, which consists of 

thin-bedded limestone containing interbedded lamellae 

of limy shale; (4) a middle gray limestone 200 to 300 

feet thick, which consists of thick-bedded massive limestone; and (5) an upper gray limestone, about 100 to 

150 feet thick, which consists of thin-bedded limestone 

and shaly limestone. The thin-bedded limestones, members 3 and 5, are commonly oolitic, pisolitic, and nodular." (Schmidt and others, 1965, p. D114.)

In the 1965-66 field season, Schmidt collected trilobites 

from the basal beds of member 3 and from two other 

horizons about 30 feet above the base of the member 

at Mount Dover. All of these collections contain the 

Nelsonia schesis faunule. Trilobites of this faunule 

and the Amphoton oatesi faunule were also collected 

earlier from unknown horizons within the Nelson Limestone about 8 miles to the northeast. Thus, in the Neptune 

Range area, the oldest limestone beds in the Cambrian 

section are medial or late Middle Cambrian in age.

In the Heritage Range, a partial section of Cambrian 

and possible Cambrian rocks includes a limestone unit 

ranging from 25 to 300 feet in thickness near the top 

that has yielded a rich trilobite-mollusk assemblage 

of Late Cambrian age (Webers, 1965). Below this is 

about 2,000 feet of dark pelitic rocks with rare thin 

carbonate interbeds; this overlies another limestone unit 

about 900 feet thick that has not as yet yielded any 

fossils (Craddock and others, 1964).

In the Harold Byrd Mountains, a sequence of limestones and shales above a unit of coarse arkosic arenites 

and below a unit of rhyolitic volcanic rocks. (V. H. 

Minishew, written commun., July 1966) has yielded a 

single collection of trilobites from a badly deformed 

and slightly metamorphosed limestone bed. Minishew 

believes that these units are unconformable above an 

older and more metamorphosed sedimentary sequence.

In the Nimrod Glacier-Beaumont Bay region of 

southern Victoria Land, Grindley and Laird (1969) 

have reported about 20,000 feet of limestones and terrigenous rocks assigned to the Shackleton Limestone. 

Massive limestones in the lowest exposed limestone unit 

in the type section have yielded archaeocyathids described by Hill (1964) that are comparable in age to 

the oldest trilobite-archaeocyathid associations at Mount 

Spann.

REGIONAL CORRELATION WITHIN ANTARCTICA

The key unit for regional correlation and interpretation of the regional stratigraphy is the Nelson Limestone. This is a part of a relatively thin Cambrian sequence that has a base no older than medial Middle 

Cambrian; it occupies a central position in the Transantarctic Mountains in the Atlantic sector. Toward 

the Weddell Sea, the Schneider Hills of the Argentina 

Range have outcrops of archaeocyathid-bearing limestones that must be older than the Nelson Limestone. 

Closer to the coast, the boulders from Mount Spann 

contain trilobite faunules found also in the Nelson 

Limestone as well as older archaeocyathid faunas. If 

the Heritage Range is placed on the Atlantic extension 

of the Transantarctic Mountains, as suggested by 

Schopf (1969), the Cambrian section there represents 

a still more seaward location, and the thick section of 

gray pelites with thin limestone interbeds that underlies the limestone unit bearing Late Cambrian trilobites could represent deeper water sediments beyond 

the main areas of carbonate sedimentation. Some confirmation of this would come from discovery of agnostid 

trilobites in the pelitic sequence, because these trilobites are only abundant in deposits below water bodies 

that had free access to the open ocean (Palmer, 1972). 

Because the Nelson Limestone has yielded trilobites only 

from its basal beds and these are of late Middle Cambrian age, it is reasonable to suggest that the younger 

beds of the formation could correlate with the thin 

Late Cambrian limestone of the Heritage Range.

In the Ross Sea sector of the Transantarctic Mountains, the section in the Harold Byrd Mountains is 

analogous to the section in the Neptune Range. The 

trilobite-bearing limestone unit is, at least in part, of 

Middle Cambrian age and probably correlative with 

the Nelson Limestone. In both areas, the trilobitebearing limestones are overlain by a unit of volcanic 

rocks. Although the terrigenous units underlying the 

limestones in both areas differ in thickness, they are 

unconformable on older deformed and metamorphosed 

sediments.

In southern Victoria Land, the extremely thick carbonate succession of the Shackleton Limestone has 

archaeocyathids in its lower beds that are comparable 

in age to the oldest beds dated in the Mount Spann area. 

Documentation for the age of the younger part of the 

Shackleton Limestone has not yet been presented, but 

it could include most of the Cambrian System and 

be analogous to the formation or formations that 

yielded the boulder sequences at Mount Spann.

Figure 3 is a speculative diagram with an interpretation of the Cambrian stratigraphic relationships of
D8 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

rZ

UJ 

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o

z

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o

HERITAGE 

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UNNAMED 

LIMESTONES

UNNAMED

PELITES

UNNAMED 

LIMESTONES

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ARGENTINA 

RANGE

7

^

UNNAMED 

LIMESTONES 

(SOURCE OF 

BOULDERS AT

MOUNT 

SPANN)*

UNNAMED

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LIMESTONES

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NEPTUNE 

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FORMATION

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SOUTH 

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FIGURE 3. Correlation chart suggesting possible relations of the Cambrian rock units of Antarctica. Dots indicate level

of beds in which fossils have been found.
EARLY AND MIDDLE CAMBRIAN TRULOBITES FROM ANTARCTICA D9

Antarctica. Further work in Antarctica should develop 

new evidence to test the ideas expressed here.

SYSTEMATIC PALEONTOLOGY

The classification of the Early and Middle Cambrian 

trilobites of Antarctica is summarized below. The taxa 

are listed in the order that they appear on the following pages. A diagnosis or description is provided for 

each species and for new genera. Lack of discussion of 

a supraspecific taxon indicates acceptance of this taxon 

as it is constituted in Part O of the "Treatise on Invertebrate Paleontology" (Harrmgton and others, 

1959) unless otherwise indicated. Most descriptive terms 

used here are defined or illustrated in the Treatise on 

pages 42, 44, 46, 47, and 117-126.

All illustrated specimens have been given U.S. National Museum catalog numbers and are deposited in 

the collections of that institution. The collection numbers are recorded in the Cambrian-Ordovician locality 

catalogs of the U.S. Geological Survey.

All figures show the exterior of the exoskeleton unless 

otherwise specified. All dimensions in the vertical plane 

that includes the axis of symmetry of the trilobite are 

sagittal dimensions, those in planes parallel to the sagittal plane are exsagittal dimensions, and those in a vertical plane at right angles to the sagittal plane are transverse dimensions. Particular dimensions on all parts 

were measured as straight-line distances between furrows or from margins to furrows as described earlier 

(Palmer, 1965, p. 23).

SUMMARY OF CLASSIFICATION OF ANTARCTIC EARLY AND 

MIDDLE CAMBRIAN TRILOBITJES

Agnostida

Agnostina

Quadragnostidae

Peronopsis Hawle and Corda 

P. cf. P.fallax (Linnarsson) 

Eodiscina

Pagetiidae

Pagetia Walcott 

P. longispina n. sp. 

Pagetides Rasetti 

P.? antarcticus n. sp. 

Redlichiida

Neoredlichiidae

Australaspis n. gen. 

A. magnus n. sp. 

Paradoxididae

Xystridura Whitehouse 

X. glacia n. sp. 

X. multilinia n. sp. 

Protolenidae

Chorbuslina Lazarenko 

C. subdita n. sp. 

C. wilkesi n. sp. 

Redlichiidae

Redhchia Cossmann 

RedlicMa sp.

Corynexochida

Dolichometopidae

Amphoton Lorenz

A. oatesi n. sp. 

Dorypygidae

Kootenia Walcott

K. styrax n. sp.

Olenoides Meek

Olenoides sp. 

Jakutidae

Bathyuriscellus Lermontova

B. australis n. sp.

B. modestrs n. sp. 

Oryctocephalidae

Goldfieldia Palmer

G. ninguis n. sp. 

Ptychopariida

Anomocaridae

Chondranomocare Poletaeva

C. australis n. sp. 

Asaphiscidae

Liopeishania Chang

L. spannensis n. sp. 

Conokephalinidae

Suludella Yegorova and Savitskiy

SJ davnii n. sp.

S.f spinosa n. sp. 

Nepeidae

Trinepea n. gen.

T. trinodus n. sp. 

Solenopleuridae

Solenopleura Angelin

S. pruina n. sp. 

Unassigned trilobites

Glabrella Lermontova

G.f pitans n. sp.

Nelsonia n. gen.

N. schesis n. sp.

Pensacola n. gen.

P. isolata n. sp.

Schopfaspis n. gen.

S. granulosus n. sp.

Genus and species undetermined 1

Genus and species undetermined 2

Genus and species undetermined 3

Genus and species undetermined 4

Order AGNOSTIDA Kobayashi

Suborder AGNOSTINA Salter

Family dUADRAGNOSTIDAE Howell

Genus PERONOPSIS Hawle and Corda

Peronopsis Hawle and Corda, 184", p. 115; Robinson, 1964, p. 

529; Palmer, 1968, p. 31 (see this for full synonymy).

Type species. Battus integer Beyrich, 1845, p. 44, 

pi. 1, fig. 19.

Discussion. The diagnosis of this genus by Robison 

(1964) summarizes the current concept of this common 

Middle Cambrian genus to which the Antarctic species 

conforms fully.
D10 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

Peronopsis cf. P. fallax (Linnarsson) 

Plate 4, figures 6, 7

Agnostus chinensis Dames. Walcott, 1913, p. 99, pi. 7, figs. 4, 4a,

4b. 

Peronopsis fallax minor (Brogger), Westergard, 1946, p. 38, pi. 3,

figs. 4, 5, 7. 

Peronopsis fallax (Linnarsson), Chernysheva, 1961, p. 48, pi. 1,

figs. 15-18. 

Peronopsis ex. gr. fallax (Linnarsson), Yegorova and Savitskiy,

1969, p. 107, pi. 6, figs. 1-7.

Discussion. The specimens cited above all share with 

the Antarctic specimens a well-defined bilobed glabella, 

no trace of a preglabellar median furrow, a long welldefined bluntly pointed pygidial axis that reaches to 

the posterior border furrow, a well-developed axial node 

on the pygidium, and no traces of transverse furrows 

on the pygidial axis.

A name for this group is not clear. When Endo and 

Eesser (1937) described A. comes, which might be an 

appropriate name, they included not only the specimens 

figured by Walcott (1913), but also other specimens 

with well-developed furrows at the sides of the pygidial axis, and they stressed this character in their comments (Endo and Eesser, 1937, p. 161). Thus, although 

no type was designated, their most representative specimens were not the specimens with an unfurrowed axis.

All other citations to Peronopsis specimens with an 

unfurrowed axis reaching to the border furrow are 

made with varying degrees of confidence to P. fallax, 

an apparently variable species which typically has a 

slightly shorter axis with indications of one or two 

furrows. Until a major revision of the species of Peronopsis is made, I prefer not to suggest another taxonomic assignment for the Antarctic species, and they 

are tentatively referred to P. fallax. This kind of agnostid has been reported only from beds of late Middle 

Cambrian age, that is, temporally equivalent to the 

American Bolaspidella zone.

Occurrence. Amphoton oatesi faunule. Moderately 

common (11 cephala, 11 pygidia), USGS colln. 4446- 

CO, Nelson Limestone, Neptune Range.

Suborder EODISCINA Kobayashi 

Family PAGETIIDAE Kobayashi

Genus PAGETIA Walcott

Pagetia Walcott, 1916, p. 407; Cobbold, 1931, p. 462; Lermontova, 1940, p. 121; Richter and Richter, 1941, p. 17; 

Kobayashi, 1943, p. 40; Kobayashi, 1944, p. 63; Shimer 

and Shrock, 1944, p. 615; Rasetti, 1945, p. 315; Lermontova, 1951b, p. 36; Yegorva and others, 1955, p. 104; 

Howell, 1959, p. 189; Pokrovskaya, 1960, p. 55; Yegorova, 

1961, p. 215; Repina and others, 1964, p. 253; Lazarenko, 

1964, p. 176; Rasetti, 1966, p. 503; Palmer, 1968, p. 35.

Type species. Pagetia lootes Walcott, 1916, p. 408, 

pi. 67, figs, la-11

Discussion. The characteristics of Pagetia have 

been thoroughly reviewed by Rasetti (1966), and the 

Antarctic species described below conforms in all 

essential respects to Rasetti's concept of the genus.

Pagetia longispina Palmer n. sp. 

Plate 3, figures 1-6

Description. Cephalon semicircular, gently convex 

transversely and longitudinally, moderately to strongly 

rounded anteriorly. Glabella well defined by broad deep 

axial furrows, tapered forward, bluntly pointed anteriorly. Occipital and glabellar furrows absent; posterior part of glabella extends backward into long 

slender horizontal spine about as long as glabella. 

Frontal area divided into broad, gently convex border 

and slightly narrower brim with median depression in 

front of glabella. Sagittal length of border slightly less 

than one-half length of glabella exclusive of spine.

Fixed cheeks gently convex, horizontal; width, exclusive of palebral lobes, slightly more than basal 

glabellar width. Narrow ocular ridge extends in gentle 

curve laterally from anterior part of glabella to small 

well-defined palebral lobes situated opposite glabellar 

midlength.

Posterior limbs broad exsagittally; transverse length 

slightly less than twice basal glabellar width; posterior 

border expands distally and bears short fixigenal spine. 

Posterior border furrow moderately broad, deep, curved 

forward distally.

Anterior and posterior sections of facial sutures subparallel, directed slightly anterolaterally from ends of 

palpebral lobe. Ornamentation consists of scattered 

granules on the cranidial border only. Radiating furrows are present on the border of some specimens.

Pygidium semicircular, gently convex transversely 

and longitudinally. Axis slender, elevated above pleural 

regions, tapered very slightly posteriorly, reaches 

nearly to narrow posterior border; width at anterior 

margin slightly more than one-third width of pleural 

region; posterior part continued into slender, horizontal 

spine about as long as pygidium. Two distinct ring furrows present posterior to articulating furrow on axis; 

each ring has low, broad median node. Pleural regions 

have narrow, weakly developed pleural furrows; only 

anterior pair retained on largest specimens. Border narrow. Lateral margin smooth. External surfaces of all 

parts smooth.

Discussion. This species differs from all others in 

the genus by having a combination of relatively well 

defined palpebral lobes, narrow ocular ridges, granular ornamentation on the cranidial border only, and 

short fixigenal spines.

Occurrence. Xystridura multilinia faunule. Rare
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA Dll

(10 cranidia, seven pygidia), USGS colln. 6333-CO, 

boulder from moraine on Mount Spann.

Genus PAGETIDES Rasetti

Pagetides Rasetti, 1945, p. 311; Howell, 1959, p. 190; Lazarenko, 

1959, p. 5; Rasetti, 1967, p. 63; Palmer, 1968, p. 36.

IPagetina, Lermontova, 1940, p. 121 [not Pagetina Barnard, 

1931] ; Lermontova, 1951b, p. 27.

INeopagetina, Pokrovskaya, 1960, p. 56; Yegorova, 1961, p. 217; 

Lazarenko, 1962, p. 37; Lazarenko, 1964, p. 177.

Type Species. Pagetides elegans Rasetti, 1945, 

p. 313, pi. 1, figs. 15-18.

Diagnosis. "Pagetidae that have a well-developed, 

strongly upturned occipital spine and well-defined 

palpebral furrows; and that lack significant development of axial pygidial spines" (Palmer, 1968, p. 36).

Discussion. The difficulties of distinguishing Pagetides from Neopagetina have been discussed by Rasetti 

(1967) and Palmer (1968). The Antarctic species conforms in most respects to the characteristics of Pagetides (sensu stricto) but differs in several possibly 

critical characters that raise questions about its generic 

assignment.

Examination of the 14 species assigned to Pagetides 

shows that eight bear a medially expanded cephalic border, three do not, and it is not clearly present on three 

Others. Six eastern North American species (Pagetides 

ampliforns Rasetti, P. elegans Rasetti, P. leiopygus 

Rasetti, P. minutus Rasetti, P. pustulosus Rasetti, and 

P. rupestris Rasetti) and two Soviet species (P. rjonsnitzkii Lermontova and P. primaeva Lermontova) appear to form a group characterized by an expansion of 

the anterior cephalic border. Two Alaskan species 

(P. occidentals Palmer and P. granulosu-s Palmer) and 

the Antarctic species (P. antarcticus n. sp.) characterize 

another group not bearing such an expansion.

In addition, the Antarctic species lacks distinct 

palpebral lobes, and the occipital spine is not upturned 

as in typical species of the genus. If this species is to be 

retained in Pagetides, the generic diagnosis will have to 

be modified, and the principal diagnostic features of 

tfagetides will be a narrow, multisegmented pydigial 

axis lacking a terminal axial spine. Until more species 

are found that share the distinctive characteristics of 

tjie Antarctic species, I hesitate to separate it from 

Pagetides.

Pagetides? antarcticus n. sp.

Plate 5, figures 1-7

Description. Complete specimen ovoid, twice as long 

as wide. Cephalon semicircular, uniformly downsloping from tip of occipital spine to anterior border. Genal 

spines absent.

Glabella tapered forward, strongly convex transversely and well defined by deep axial furrows; anterior 

end strongly rounded; anterior lobe almost circular, 

variable in shape and separated from posterior lobe by 

a broad barely apparent transverse furrow; other 

glabellar furrows not distinctly discernible. Occipital 

furrow indistinct, variable in depth. Occipital ring 

poorly defined, extended into a short blunt spine of 

variable shape. Frontal area subequally divided into 

brim and border on axial line; sagittal length about 

four-tenths glabellar length including occipital ring, 

divided by a broad shallow depression in front of the 

glabella, slightly convex transversely. Anterior border 

furrow generally absent in front of glabella; border 

defined laterally by change in slope of frontal area. 

Border almost flat to flatly convex, not expanded in 

front of glabella; radial grooves barely apparent on 

some specimens.

Fixed cheeks as wide as glabellar base, convex, upsloping laterally, more inflated posteriorly. Ocular 

ridges present only in young stages; not present externally or internally in adult stages. Palpebral furrows 

absent.

Posterior border furrow deep at genal angle, divided 

anterolaterally, fades into posterior border midway 

from genal angle to axial furrow. Posterior border 

elevated at genal angle. Point of geniculation directly 

posterior to eye.

Anterior section of facial suture straight, directed 

forward at 70° to axial line; course of posterior section 

straight, perpendicular to border and axial line.

Free cheek simple, exsagittal length three times the 

width, consists of the border with narrow (transverse) 

slightly inflated subocular area. Eye surface not preserved. Length of eye about one-fourth sagittal length 

of glabella including occipital spine; line connecting 

anterior ends of eyes crosses glabella just behind 

anterior lobes.

Thorax of two segments. Width of segments slightly 

less than maximum width of pygidium; anterior segment with wide (sagittal) articulating half-ring; axial 

ring low and narrow. Pleural furrows developed on 

distal half of pleurae only, pleural tips directed posteriorly. Posterior segment has blunt axial node, pleural 

tips directed forward.

Pygidium as wide at anterior margin as maximum 

width of cephalon, tapering more rapidly than cephalon 

so as to fit inside cephalic doublure; outline semicircular ; strongly inflated. Axis clearly defined anteriorly, 

barely apparent posteriorly, five or six ring furrows 

apparent posterior to articulating furrow; anterior 

three rings bear moderately large axial nodes. Axial 

width one-quarter greatest pygidial width. Pleural 

regions smooth, except on youngest individuals where
D12 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

shallow furrows are barely apparent. Pygidial border 

narrow, one-tenth anterior axial width. Articulating 

facet as long transversely as half maximum pleural 

width.

External surfaces of all parts generally smooth. 

Fixed cheeks of some specimens have crude shallow pits 

only after whitening.

Discussion. This species differs from all other species of Pagetides by having a short, subhorizontal 

occipital spine and by lacking distinctly defined palpebral lobes. The uniform width of the cephalic border, 

poor definition of the border in front of the glabella, 

and presence of axial nodes on the first three axial segments of the pygidium are additional distinctive 

characteristics. Eeasons for questioning the generic 

assignment are given in the generic discussion.

The probability that this species is from beds of 

medial or late Middle Cambrian age, whereas all other 

species of Pagetides are found in beds of Early Cambrian age, also raises doubts about the real relationship 

of this species to undoubted representatives of 

Pagetides.

Occurrence. Schopfaspis granulosus faunule. Common (>40 cranidia and pygidia; one complete specimen) , USGS colln. 6313-CO, 6325-CO, 6327-CO, 636^- 

CO, boulders from moraine on Mount Spann.

Order REDLICHIIDA Bichter 

Family NEOREDLICHIIDAE Hup6

The general characteristics of the Neoredlichiidae 

and a good discussion of the generic content of this 

family are given by Repina (1966). The Antarctic 

species described below has the long convex palpebral 

lobes, short frontal area, and divided ocular ridge 

characteristic of several genera of Neoredlichiidae, such 

as Resserops and Bulaiaspis, and is here added to that 

family.

Genus AUSTRALASPIS n. gen.

Type species. Australaspis magnus n. sp.

Diagnosis. Neoredlichiidae that have glabella elongate, gently tapered, bluntly rounded anteriorly, reaching to anterior border; sides slightly concave. Palpebral 

lobes elongate, strongly curved. Ocular ridge bifurcated 

towards the glabella with anterior branch continuous 

around and adaxial to the anterolateral corners of the 

glabella. Posterior limbs moderately long, slender.

Free cheek has broad-based genal spine continuing 

curvature of lateral margin.

Pygidium has broad axis reaching nearly to posterior 

margin, with four narrow axial rings. Pleural regions 

less than half width of axis. Margin smoothly curved.

Discussion. Cranidia of the type species of this

genus most closely resemble some of those assigned to 

Bulaiaspis (Repina, 1966). However,, specimens and 

replicas were examined of several Bulaiaspis species 

provided by Dr. L. N. Repina of the Institute of Geology and Geophysics at Academgorodok, Siberia, 

U.S.S.R., and the Antarctic species differs from species 

of Bulaiaspis by having slightly concave sides to the 

glabella and particularly by having relatively long 

slender posterior limbs. The pygidium has a much 

broader axis than pygidia known for any genus of the 

Neoredlichiidae.

For these reasons, the Antarctic species is assigned to 

a new genus.

Australaspis magnus n. sp. 

Plate 1, figures 1-8

Desecription. Cranidium subquadrate, gently convex 

transversely and longitudinally; width between palpebral lobes slightly greater than length. Glabella 

moderately to poorly defined by changes in slope of 

exoskeleton; sides sub-parallel or slightly concave most 

distinct behind ocular ridges; anterior end poorly defined, bluntly rounded, separated from border by anterior branch of ocular ridge that wraps around glabellar front. Three pairs of glabellar furrows moderately 

deep on cranidia less than 1 cm (centimeter) in length, 

moderately to very deep on larger specimens; posterior 

pair curved slightly backward; large specimens have 

shallow fourth pair of furrows opposite junction with 

ocular ridge. Occipital furrow moderately deep. Occipital ring has axial node on posterior margin. Frontal 

area consists only of gently convex border. Border furrow shallow, curves backward from distal parts of 

frontal area towards anterolateral corners of glabella 

so that border is distinctly broader in front of glabella. 

Sagittal length of border increases from one-fifth to 

about two-fifths of sagittal glabellar length, exclusive of 

occipital ring, from small to large specimens.

Fixed cheek wide, flat, horizontal or slightly upsloping; width, exclusive of palpebral lobe, one-half or 

slightly more than one-half basal glabellar width. Palpebral lobes long, strongly curved, raised above cheek 

level and continuous with ocular ridge; exsagittal 

length between two-thirds and three-fourths sagittal 

glabellar length exclusive of occipital ring; line connecting posterior tips passes over glabella just anterior 

to occipital furrow. Ocular ridge divided by shallow 

furrow so that poorly defined anterior part continues in 

sigmoid course around anterolateral corners of glabella.

Posterior limb, slender, sharply pointed, transverse 

length about equal to basal glabellar width. Posterior 

border furrow shallow.

Course of anterior section of facial suture slightly
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D13

divergent forward from palpebral lobe to strongly 

curved anterolateral corners of cranidium. Course of 

posterior section divergent-sinuous.

Free cheek gently convex, lateral margin evenly 

curved. Border gently convex, slightly narrower than 

anterior breadth of ocular platform, denned by shallow 

lateral border furrow that meets shallow posterior border furrow at sharply rounded angle near base of genal 

spine. Genal spine long, slender; total length not known, 

but it exceeds length of posterior section of facial suture.

Pygidium(?) subovate, moderately convex transversely and longitudinally. Axis very broad, low, barely 

tapered, extended nearly to posterior margin, poorly 

defined; width slightly greater than two-thirds width 

of pygidium; one complete ring furrow and three furrows impressed only at sides of axis are present posterior to articulating furrow. Pleural regions small, border absent; one or two shallow furrows on inner part. 

Margin smooth.

External surfaces of all convex parts covered by very 

fine, closely spaced granular ornamentation.

Discussion. The differences between this species and 

other Neoredlichiidae are reviewed in the generic discussion. A. magnus is more variable than many trilobites in development of the glabellar furrows and in the 

distinctness of the border furrows and the furrows on 

the ocular ridges. This may be related to the comparatively large size of some specimens. Fragments indicate 

that cranidia 2 to 3 cm long were present.

Occurrence. Australaspis magnus faunule. Common 

(>40 cranidia, seven free cheeks, and two pygidia), 

USGS collns. 5939-CO, 6311-CO, boulders from 

moraine on Mount Spann.

Family PARADOXIDIDAE Hawle and Corda 

Subfamily XYSTRIDURINAE Whitehouse

Genus XYSTRIDTTRA Whitehouse

Xystridura Whitehouse, 1936, p. 74; Whitehouse, 1939, p. 197; 

Poulsen, 1959, p. 214.

Type species. Milesia templetonensis Chapman, 1929, 

p. 214 (synonymized with Bathyuriscus saint-smithi 

Chapman, 1929, p. 209, by Whitehouse, 1939, p. 199).

Discussion. Whitehouse (1939, p. 197) gives a good 

description of this genus that needs to be modified only 

by being less specific about the number of pygidial border spines to accommodate the Antarctic species described below. Trilobites of this genus differ from those 

assigned to Paradoxides by having the posterior glabeller furrows not connected across the glabella, generally 

wider fixed cheeks, a rostral plate separate from the 

hypostome, and a wide pygidium with several pairs of 

border spines.

Whitehouse (1936, p. 74) created confusion with regard to the type species of Xystridura that has been 

rectified in part by Opik (1957, p. 40) but without 

comment. Whitehouse unequivocally proposed Xystridura to replace the preoccupied name Milesia, Chapman, 

1929 [not Latrielle, 1804]. Thus the type species for 

Xystridura automatically became Milesia templetonensis, the only species assigned by Chapman to Milesia. 

The designation by Whitehouse of Ol-enellm^. ^rownii 

Etheridge as the type species was improper according 

to the rules of zoological nomenclature (Int. Kules Zool. 

Nomenclature, 1961, p. 65, Art. 67i). Further complication was added when Whitehouse (1939, p. 199), as 

first revisor, placed Milesia templetonensis in the synonymy of Xystridura saint-smithi (Chapman) and thus 

saint-smithi is the present valid name for the type 

species of Xystridura and not templetonensis as claimed 

by Opik (1957, p. 40; 1968, p. 136) (see Int. Kules Zool. 

Nomenclature, 1961, p. 25, Art. 24a).

Xystridura glacia n. sp.

Plate 3, figures 9,13-17

Description. Cranidium subquadrate, width slightly 

greater than length; anterior margin gently and evenly 

curved. Glabella long, low, unequally hourglass shaped, 

defined by abrupt change in slope from brim and fixed 

cheeks. Sides converge slightly forward from occipital 

ring to posterior glabellar furrow, than diverge forward 

to junction with poorly defined ocular ridges; margin 

anterior to ocular ridges nearly a semicircle; anterior 

end reaches nearly to border furrow. Two or three pairs 

of shallow glabellar furrows present; posterior pair 

directed slightly backward; middle pair almost straight 

transversely; anterior pair directed slightly forward; 

all furrows extend inward from sides of glabella about 

one-third glabellar width. Occipital furrow deep at sides 

of glabella, shallow or absent over axis. Frontal area 

consists of extremely narrow brim on axial line and 

gently convex, moderately wide border that maintains 

nearly constant sagittal and exsagittal length; sagittal 

length of frontal area about one-eighth sagittal length 

of glabella including occipital ring; sagittal length of 

brim about one-fourth sagittal length of border.

Fixed cheeks nearly flat, horizontal; width, including 

poorly defined palpebral lobe, about equal to glabellar 

width on line through posterior glabellar furrows. 

Palpebral lobes strongly curved, situated opposite 

posterior part of glabella; exsagittal length on large 

specimens slightly less than one-half sagittal glabellar 

length including occipital ring; posterior end adjacent 

to posterior border furrow; width about one-fourth of 

intraocular part of fixed cheek.

Posterior limb, adjacent to posterior section of facial

452-253 O - 72 - 3
D14 ^CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

suture, short, bluntly rounded, not extended laterally 

beyond margin of palpebral lobe; transverse length 

from occipital ring about two-thirds basal glabellar 

width.

Course of anterior section of facial suture moderately 

divergent forward from palpebral lobe to border furrow, then curved inward across border. Course of posterior section strongly curved from posterior end of 

palpebral lobe to posterior margin.

Hypostome, known only from fragments, has large 

inflated anterior body.

Free cheek narrow; lateral and posterior borders defined by shallow border furrows that meet in sharp 

curve at genal angle. Width of border lateral to eye 

notch slightly less than width of ocular platform. Genal 

spine long, slender; lateral margin continues curvature 

of cheek margin; distance from tip to inner genal angle 

about twice distance from inner genal angle to posterior 

section of facial suture.

Structure of thorax and number of thoracic segments 

not known.

Pygidium has axial length about twice width at 

anterior margin. Axis elevated above pleural regions, 

defined at sides by abrupt change in slope, not defined 

posteriorly; one distinct ring furrow present posterior 

to articulating furrow. Pleural regions gently convex, 

bear three or four shallow posterolaterally curved and 

divergent furrows that disappear before reaching margin ; distal parts of first, third, and fourth furrows point 

to bases of border spines. Margin bears three pairs of 

spines decreasing in length posteriorly; distance between middle pair and posterior pair about equal to 

distance between posterior pair, distinctly less than distance between anterior pair and middle pair; all spines 

directed nearly straight posteriorly.

External surfaces of all parts .except border regions 

smooth. Borders of cranidium, free cheek, and pygidium 

have low terrace lines; on mold, surfaces of brim and 

fixed cheek, exclusive of palpebral lobe, have dense network of anastomosing caecae.

Discussion. The presence of three pairs of border 

spines distinguishes this species from X. saint-smithi 

(Chapman). The differences between this and X. multilinia n. sp. are discussed under that species.

Several immature cranidia of X. glacia (pi. 3, figs. 

15,16) are characterized by having a wide brim in front 

of the glabella traversed by a median longitudinal 

preglabellar ridge analogous to the ridge on species of 

Paedeumias. Similar cranidia were illustrated by 

Whitehouse (1939, pi. 21, fig. 16) for X. saint-smithi. 

Such changes in the structure of the frontal area seem 

to be characteristic of many paradoxidid trilobites (cf. 

Hutchinson, 1962; Snadjr, 1958).

Occurrence. Xystridura glacia faunule. Common 

(six cranidia, two free cheeks, four pygidia only 

trilobite in sample), USGS colln. 5938-CO, boulder 

from moraine, Mount Spann.

Xystridura multilinia n. sp. 

Plate 2, figures 18-25

Description. Cranidium subquadrate, width slightly 

greater than length; anterior margin a slightly parabolic curve. Glabella long, low, unequally hourglass 

shaped, defined by abrupt change in slope from brim 

and fixed cheeks. Sides converge gently forward from 

occipital ring to posterior glabellar furrow, then 

diverge forward to junction with ocular ridge; anterior 

to ocular ridge sides again converge forward in gentle 

curve to bluntly pointed anterior end of glabella adjacent to border furrow; width of glabella at posterior 

glabellar furrows about two-thirds width at ocular 

ridges. Two pairs of glabellar furrows apparent; 

posterior pair deep, directed slightly posteriorly; 

anterior pair shallow, directed nearly straight laterally ; furrows extend inward from glabellar sides about 

one-third of glabellar width. Occipital furrow deep 

near sides of glabella, continuous across axial line only 

on small specimens. Occipital ring has low median node. 

Frontal area consists only of narrow, gently convex 

slightly downsloping border in front of glabella; sagittal length of border about one-tenth of sagittal length 

of glabella including the occipital ring. Anterior border 

furrow shallow, deepens slightly towards facial sutures.

Fixed cheek nearly flat, horizontal; width, including 

palpebral lobe, about equal to basal glabellar width on 

line through posterior glabellar furrows. Palpebral lobe 

broad, gently convex, poorly defined, strongly curved, 

situated opposite posterior part of glabella; width about 

two-thirds of interocular part of fixed cheek; relative 

length decreases with increasing size from slightly 

more than one-half sagittal glabellar length exclusive 

of occipital ring on small specimens, to about one-third 

sagittal glabellar length on large specimens; posterior 

tip adjacent to posterior border furrow.

Posterior limb, adjacent to posterior section of facial 

suture, short, bluntly rounded, not extended laterally 

beyond margin of palpebral lobe; transverse length 

about four-fifths basal glabellar width.

Course of anterior section of facial suture moderately 

divergent forward from palpebral lobe to anterior 

margin. Course of posterior section strongly curved 

from posterior end of palpebral lobe to posterior 

margin.

Hypostome has large, inflated anterior body; posterior body short, with narrow, convex, striated posterior
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D15

border; maculae well developed. Margin lateral to 

maculae has short blunt broad-based spine.

Free cheek narrow. Lateral border broad, gently 

convex, well defined by lateral border furrow that is 

continuous with posterior border furrow through a 

sharp curve at genal angle; width of lateral border 

slightly less than width of narrowest part of ocular 

platform lateral to eye notch. Genal spines slender; 

lateral margin continuous with lateral margin of 

remainder of cheek; distance from tip to inner genal 

angle about equal to length of posterior section of facial 

suture.

Number of thoracic segments and structure of thorax 

not known.

Pygidium has axial length slightly less than one-half 

greatest width. Axis moderately convex, elevated above 

pleural regions, defined at sides by abrupt change in 

slope, not defined posteriorly; width about one-fifth 

anterior pygidial width. Two ring furrows present 

posterior to articulating furrow. Pleural regions gently 

convex, bear three or four posterolaterally curved and 

divergent furrows that disappear before reaching margin ; distal parts of first, third, and fourth furrows point 

to bases of border spines. Margin bears three pairs of 

spines; two anterior pairs moderately long and slender; 

posterior pair short; distance between middle pair and 

posterior pair less than distance between posterior pair 

and between middle and anterior pairs; all spines 

directed nearly straight backward.

External surfaces of all parts except border regions 

smooth. Borders of cranidium, free cheek, and pygidium 

generally have well-developed terrace lines. All surfaces 

of internal molds smooth.

Discussion. This species is represented by abundant 

but generally fragmented parts in a trilobite coquina 

from one boulder. Thus, only relatively small specimens 

are available for illustration. Fragments indicate that 

whole individuals, based on comparison with proportions of complete Australian specimens, exceeded 75 

mm (millimeters) in length. This species differs from 

X. saint-smithi (Chapman) by having only two pairs 

of glabellar furrows developed, and by having three, 

rather than two, pairs of pygidial border spines. It 

differs from X. glacia n. sp. by having a bluntly pointed 

anterior glabellar margin, wider palpebral lobes, two 

ring furrows on the pygidial axis, less even spacing 

between the posterior two pairs of pygidial spines, and 

by lacking any evidence of a brim in front of the 

glabella.

Occurrence. Xystridura multilmia faunule. Abundant (100 fragments of various parts), USGS colln. 

6333-CO, boulder from moraine on Mount Spann.

Family PROTOLENIDAE Richter and Richter 

Genus CHORBTJSTJLINA Lazarenko

Chorbusulina Lazarenko, 1962, p. 56; Lazarenko, 1964, p. 196; 

Yegorova and iSavitsky, 1969, p 134.

Type species. Chorbusulina bella Lazarenko, 1962, 

p. 56, pi. 6, figs. 1-5.

Discussion. Chorbusulina is a monotypic genus of 

small Early Cambrian trilobites characterized by a 

short broad frontal area with a narrow well-defined 

border and a median transversely elongate swelling on 

the brim; a well-defined anteriorly tapered, furrowed, 

bluntly rounded glabella; eye ridges that are continuous with posteriorly located palpebral lobes; and short 

posterior limbs not extending laterally beyond the outer 

margins of the palpebral lobes. It is most closely similar 

to another monotypic genus, Charaulaspis (Lazarenko, 

1962, p. 54), but differs by having the glabella elevated 

so that it does not appear sunken between the fixed 

cheeks and the swelling on the brim. Both genera are 

found in the upper part of the Judomia zone at the top 

of the Aldan Stage in northern Siberia.

The Antarctic species described below seem to conform in most important respects to the concept of 

Chorbusulina and are not closely similar to any other 

described trilobites.

Chorbusulina subdita n. sp. 

Plate 2, Figures 11-15

Description. Cranidium subquadrate, gently convex 

transversely and longitudinally, moderately rounded 

anteriorly; width slightly greater than length. Glabella 

gently convex transversely and longitudinally, tapered 

slightly forward, bluntly rounded anteriorly, moderately well defined by broad shallow axial and preglabellar furrows; sides straight or slightly bowed outward. 

Three pairs of glabellar furrows barely apparent. Occipital furrow broad, shallow, deepest near posterolateral corners of glabella. Occipital ring gently convex 

and longest in sagittal plane; median node situated adjacent to posterior margin. Frontal are gently downsloping ; sagittal length one-half to slightly more than 

one-half length of glabella exclusive of occipital ring. 

Border narrow, flat or gently convex, best defined on 

small specimens, not apparent on some larger specimens; 

sagittal length slightly more than one-half sagittal 

length of gently convex brim. Brim somewhat more 

convex than border, has broad low median swelling that 

is defined posteriorly by broad shallow furrow extending slightly forward towards anterolateral corners of 

cranidium from anterolateral corners of glabella.

Fixed cheek gently convex, horizontal; width, exclusive of palpebral lobe between one-half and two-thirds
D16 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

basal glabellar width. Ocular ridge broad, indistinct, 

directed only slightly posterolaterally from axial furrow opposite anterior end of glabella. Palpebral lobe 

gently arcuate, poorly defined anteriorly, situated opposite posterior part of glabella; transverse width between one-third and one-half that of inf raocular part of 

cheek; exsagittal length between one-half and twothirds sagittal glabellar length exclusive of occipital 

ring.

Posterior limb short, blunt, not extended laterally 

beyond outer edge of palpebral lobe; transverse length 

about two-thirds basal glabellar width; exsagittal 

length slightly more than one-third exsagittal length 

of palpebral lobe. Posterior border furrow broad, 

shallow.

Course of anterior section of facial suture slightly 

divergent forward from palpebral lobe, curved across 

border to anterior margin and continued along margin 

to sagittal line. Course of posterior section of facial 

suture directed slightly outward in broad curve from 

palpebral lobe to posterior margin.

Free cheek narrow; border lateral to large, convex 

eye notch is slightly wider than ocular platform. Posterior margin of cheek directed anterolaterally so that 

moderately long genal spine was somewhat advanced on 

cephalon; lateral margin of genal spine continuous with 

cheek margin. Anterior extension of doublure extended 

to sagittal plane of cephalon.

Rostral plate apparently absent; hypostome, thorax, 

and pygidium unknown.

External surface of exoskeleton on specimens that 

have glabellar lengths greater than 1 mm has fine scattered granules principally in axial furrows; top of 

glabella and occipital ring, surface of swelling on brim, 

border, outer parts of fixed cheeks, and palpebral lobes 

smooth. However, smaller specimens have fine granular 

ornamentation on all parts.

Discussion. This species is most similar to C. wilkesi 

n. sp. from which it differs principally in ornamentation of the larger specimens. In C. wilkesi, the granular 

ornamentation is retained on specimens of all sizes, 

whereas in C. subdita, specimens with glabellas longer 

than 1 mm have increasingly subdued granulation of the 

convex parts of the cranidium and loss of clarity of the 

occipital and border furrows. These differences are consistent between samples and are interpreted here to be 

differences between species.

C. subdita differs from the type and only other described species C. bella Lazarenko, by having shallower 

occipital and border furrows, a less prominent and 

somewhat more laterally directed ocular ridge, and 

granular ornamentation on only part of the cranidium.

The absence of a rostral plate, as indicated by the

long anterior doublure on the free cheek, is an unusual 

and distinctive feature that may be characteristic for 

all species of Chorbusulina and should be looked for on 

other Asiatic Early Cambrian ptychoparioid trilobites. 

Most American Early Cambrian ptychoparioids have 

a rostral plate almost as broad transversely as the 

anterior margin of the cranidium.

Occurrence. Chorbusulina subdita faunule. Common (20 cranidia; three free cheeks), USGS colln. 

6312-CO and 6321-CO, boulders from moraine on 

Mount Spann.

Chorbusulina wilkesi n. sp. 

Plate 2, figures 1, 2

Discussion. This species is known only from cranidia that have essentially the same proportions of their 

individual parts as do cranidia of C. subdita, but that 

consistently differ in their ornamentation. Thus, the description for C. subdita suffices also for C. wilkesi exclusive of ornamentation. C. wilkesi specimens of all 

sizes are completely covered with closely spaced granules, whereas larger specimens of C. subdita are consistently smooth on their convex parts. Specimens of 

C. wilkesi also have slightly better definition of the 

border, occipital, and palpebral furrows. Forms with 

the two types of ornamentation are not found associated. For this reason, they are considered here to represent two different specific taxa within Cho-rbusulina.

This species differs from C. bella Lazarenko by having the ocular ridge narrower and not so clearly a continuation of the palpebral lobe and by having the ocular 

ridges more nearly directed straight laterally.

Occurrence. Chorbusulina wilkesi faunule. Common (>20 cranidia), USGS colln. 5937-CO, 6308-CO, 

6329-CO, 6331-CO, 6352-CO; boulders from moraine 

on Mount Spann.

Family REDIlCHHDAE Poulsen 

Genus REDIICHIA Cossman

Redlichia Oossman, 1902, p. 62; Kobayashi, 1961, p. 195 (for 

synonymy to that date) ; Sdzuy, 1961, p. 532; Rapina, 1966, 

p. 36.

Type species. Hoeferia noetlingi Redlich, 1899, p. 3, 

pi. 1, figs. 1-8.

Discussion. Trilobites assigned to Redlichia are 

found in Lower and Middle Cambrian(?) beds in 

southern Asia, Australia, and the Mediterranean region, and more than 30 species have been described for 

this genus. Their cranidia are typified by a slender, 

anteriorly tapered glabella, long palpebrad lobes terminating backward near the occipital ring, a short 

frontal area, and widely divergent anterior sections to 

the facial sutures. Associated free cheeks, when found,
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D17

indicate that the genal spine is usually advanced. A number O'f fragmentary cranidia in one Antarctic collection 

represent an indeterminate species of Redlichia.

Redlichia sp. 

Plate 2, figures 3, 4

Discussion. No complete cranidia of this Antarctic 

species have been found, but two specimens provide most 

of the important morphologic information. The cra,- 

nidia seem to represent a species of the R. nooilis group 

(Kobayashi, 1961, p. 197) which is characterized by 

having anterior sections of the facial sutures that extend 

anterolaterally from the palpebral lobe to the border 

furrow and then outward along the border furrow before curving sharply across the border. Most of the surface except the border has closely spaced granules; the 

border has well-developed terrace lines.

Redlichia forresti from northwestern Australia 

(Opik, 1958), R. noetlingi from the Salt Range in 

Pakistan (Schindewolf and Seilacher, 1955), and 

R. nobilis from north China, all have similarities to the 

Antarctic species. However, R. forresti has palpebral 

lobes much narrower transversely than the inf raocular 

part of the fixed cheek, R. noetlingi has the posterior 

glabellar furrow moderately deep and continued across 

the glabella, and R. noMlis is shown by Walcott (1913, 

pi. 7, fig. 2) to have a distinct brim. The specimen from 

Iran described by King (1937, pi. 17, fig. 1) as R. 

chinensis is remarkably similar to the Antarctic species 

(cf. pi. 2, figs. 4, 5), but, as shown by the structure 

of the frontal area, it is certainly not correctly identified. King's specimen seems to have a slightly broader 

infraocular fixed cheek than the Antarctic specimens, 

but in all other features, including ornamentation, they 

are practically indistinguishable. Until more Antarctic 

material is collected, a definitive specific identification 

is not practicable.

Occurrence. Chorbusulina wilJcesi faunule. Moderately rare (three cranidia), USGS colln. 6308-CO, 

boulder from moraine on Mount Spann.

Order CORYNEXOCHIDA Angelin 

Family DOLICHOMETOPIDAE Walcott

Genus AMPHOTON Lorenz

Amphoton, Lorenz, 1906, pi. 75; Kobayashi, 1935, p. 137; Whitehouse, 1939, p. 236; Kobayashi, 1942, p. 162; Poulsen, 

1959, p. 222; Chernysheva, 1961, p. 83; Opik, 1961, p. 139.

Type species. Amphoton steinmanni Lorenz, 1906, 

p. 75, pi. 4, figs. 15-17 (synonymized with Dolichometopus deois Walcott, 1905, p. 94 by Kobayashi, 1935, 

p. 137).

Discussion. Kobayashi (1942), Opik (1961), and 

Chernysheva (1961) have all given good discussions of

the characteristics and relationships of Ampoton. The 

Antarctic species conforms in all respects to the characteristics of this genus. Kobayashi (1942) recognized 

three subgenera: Amphotonella, which has an anteriorly 

tapered glabella; Sunia, which has an anteriorly expanded glabella, occipital spine, and undivided frontal 

area; and Fouehouia, which has an anteriorly expanded 

glabella and a well-defined cranidial border. These all 

differed from the typical subgenus which included 

forms with an anteriorly expanded glabella, undivided 

frontal area, and an occipital ring lacking a spine. 

Opik (1961) questioned the value of such subgeneric 

separations.

The Antarctic species has the occipital spine and 

essentially undivided frontal area considered by 

Kobayashi as typical for Sunia. Opik placed Sunia in 

synonymy with Amphoton because the principal differences between the subgenera were presence or absence 

of an occipital spine a character that is more often of 

value only for discrimination of species. His suggestion 

is followed here.

Amphoton oatesi n. sp. 

Plate 4, figures 8, 11-13

Description. Cranidium elongate, trapezoidal, 

gently rounded anteriorly; length exclusive of occipital 

spine, four-fifths width between tips of posterior limbs. 

Glabella elongate, unfurrowed, slightly expanded forward, bluntly rounded anteriorly, gently convex longitudinally, moderately convex transversely, well defined 

by abrupt changes in slope of exoskeleton, basal glabellar with about five-eights length, exclusive of occipital 

ring. Occipital furrow deep near axial furrows, shallow 

across axis. Occipital ring bears short, slender, slightly 

upsloping, occipital spine. Frontal area short, slightly 

downsloping; sagittal length slightly more than onefifth sagittal glabellar length exclusive of occipital ring. 

A faint, narrow transverse ridge in front of glabella 

barely outlines a brim about half as wide as border.

Fixed cheek flat, horizontal; greatest width, exclusive 

of palpebral lobe, slightly less than one-half basal 

glabellar width. Palpebral lobe gently arcuate, anterior 

end much closer to glabella than posterior end; weakly 

defined by shallow palpebral furrow paralleling palpebral margin; situated opposite middle third of glabella; 

exsagittal length about one-half glabellar length exclusive of occipital ring.

Posterior limb moderately broad based, tapered 

laterally to blunt point. Posterior border furrow 

shallow.

Course of anterior section of facial suture slightly 

divergent forward to sharply rounded anterolateral
D18 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

corners of cranidium. Course of posterior section 

divergent-sinuous.

Free cheek has moderately curved lateral margin that 

is continuous with genal spine. Border poorly defined 

by shallow lateral border furrow that disappears near 

genal angle, width at anterior margin slightly less than 

width of gently convex ocular platform. Genal spine 

short, sharp; length from tip to posterior suture about 

one-half length of sutural margin. Posterior suture 

intersects margin near base of genal spine.

Pygidium transversely subovate, lateral margins 

sharply rounded; length about one-half greatest width. 

Axis elevated, well defined at sides by changes in slope, 

tapered slightly posteriorly, bluntly rounded at back 

and connected to margin by low, posteriorly tapered 

postaxial ridge. Two moderately deep ring furrows 

present posterior to articulating furrow. First axial 

ring has low median node. Pleural regions gently convex. Border poorly defined, width about equal to greatest width of pleural platform. Two broad shallow, 

posterolaterally directed pleural furrows cross pleural 

platform but do not extend onto border.

External surfaces of all parts smooth.

Discussion. This species differs from other species 

of Amphoton that have occipital spines by having fixed 

cheeks that are almost half as wide as the posterior part 

of the glabella and by having an axial node on the first 

axial ring, two ring furrows, and two pleural furrows 

on the pygidium. In addition, A. typica Kobayashi has 

much longer genal and occipital spines; A. bensoni 

Opik has shorter palpebral lobes, sharper posterolateral 

lim'bs, and more axial and pleural furrows on the pygidium; A. spinigerum Whitehouse has long genal spines; 

and A. serotinum Whitehouse has a better defined border and much shallower ring furrows on the pygidium.

Occurrence. Amphoton oatesi faunule. Common 

(>40 cranidia, pygidia, and free cheeks), USGS colln. 

4446-CO, Nelson Limestone, Neptune Kange.

Family DORYPYGIDAE Kobayashi 

Genus KOOTENIA Walcott

Bathyuriscus (Kootenia) Walcott, 1889, p. 446.

Kootenia, Walcott, 1925, p. 92; Kobayashi, 1935, p. 156; Lermontova, 1940, p. 139; Shimer and Shrock, 1944, p. 613; 

Rasetti, 1948, p. 332; Thorslund, 1949, p. 4; Lermontova, 

1951b, p. 122; Palmer, 1954, p. 64, Hup<$, 1955, p. 91; 

Ivshin, 1957, p. 37; Poulsen, 1959, p. 218; Suvorova, 

1960a, p. 78; Chernysheva, 1961, p. 126; Lazarenko, 1962, 

p. 60; L. N. Repina, in Repina and others, 1964, p. 301; 

Suvorova, 1964, p. 86; Lazarenko, 1964, p. 204; Palmer, 

1968, p. 47.

Notasaphus Gregory, 1903, p. 155; Whitehouse, 1939, p. 241.

Type species. Bathyuriscus (Kootenia} dwiusoni 

Walcott, 1889, p. 446.

Discussion. I have recently given a diagnosis of the 

critical characters of this genus (Palmer, 1968). The 

Antarctic species conforms in all respects to this diagnosis. The diagnosis should be modified, however, with 

regard to the number of pygidial border spines. R. A. 

Robison (written commun., 1970) pointed out that 

K. mendosa Resser (1939) has only two pairs of border 

spines. Except for that species and K. styrax, described 

below, all other species of Kootenia for which pygidia 

are known have at least five pairs of border spines.

Kootenia styrax n. sp. 

Plate 4, figures 4, 5

Description. Cranidium elongate, moderately 

rounded anteriorly, moderately convex transversely, 

gently convex longitudinally. Glabella long, unfurrowed, expanded very slightly forward, straight sided, 

reaches to anterior margin, well defined at sides by 

broad, shallow axial furrows. Occipital furrow deepest 

near axial furrows, shallow on midline. Occipital ring 

has short, slender, sharp upturned occipital spine. 

Frontal area absent on axial line; lateral parts without 

well-differentiated border.

Fixed cheeks narrow, gently convex, nearly horizontal ; width, exclusive of palpebral lobe, about one-third 

basal glabellar width. Palpebral lobe gently curved, 

situated slightly posterior to glabellar midlength; palpebral furrow broad, shallow; exsagittal length of palpebral lobe about one-fourth of glabella exclusive of 

occipital ring.

Posterior limb blunt; transverse length slightly 

greater than basal glabellar width. Posterior border 

furrow broad, shallow.

Course of anterior section of facial suture nearly 

straight forward from palpebral lobe to anterior margin. Course of posterior section widely divergent behind 

palpebral lobe, strongly curved backward near tip to 

intersect posterior margin perpendicularly.

Pygidium semicircular, bears four pairs of moderately short, slender evenly spaced border spines. Axis 

prominent, sides slightly concave. Three ring furrows 

present posterior to articulating furrow. First axial 

ring distinctly wider than more posterior rings. Terminal section of axis bears prominent posteriorly directed spine. Pleural fields crossed by three pleural 

furrows. Interpleural furrows not apparent. Border 

defined only by change in slope of pleura! region; two 

anterior pleural furrows continued, but very faintly, 

across border between border spines.

External surfaces of all parts smooth.

Discussion. This species is easily distinguished from 

all other species of Kootenia by having a posteriorly 

directed axial spine on the terminal section of the
EARLY AND MIDDLE CAMBRIAN TRTLOBITES FROM ANTARCTICA D19

pygidial axis and only four pairs of border spines. All 

other species for which pygidia are known, except 

K. mendosa Resser (see generic discussion above) have 

at least five pairs of border spines, and only Kootenia 

elongata ornata (Ivshin, 1957, p. 49, pi. 2, figs. 12, 13) 

has a terminal axial spine on the pygidium.

Occurrence. Amphoton oatesi faunule. Rare (three 

cranidia, one pygidium), USGS colln. 4446-CO, Nelson 

Limestone, Neptune Range.

Genus OLENOIDES Meek

Olenoides sp. 

Plate 5, figure 18

Discussion. Two fragmentary pygidia from one 

collection have a long, well-segmented axis, pleural, and 

interpleural furrows on the pleural platforms, and a 

spinose pygidial margin all typical characteristics of 

species of Olenoides. Lack of preservation of the form 

of the pygidial spines and lack of knowledge of other 

parts prevents identification or comparison of the specimens. The species that they represent is1 characterized by having four ring furrows on the axis posterior 

to the articulating furrow, three pleural-interpleural 

furrow pairs on the pleural regions, four pairs of large 

lateral border spines, and a fifth tiny pair behind the 

axis. The external surface is covered with low closely 

spaced granules that are barely apparent on most parts 

even after whitening.

Occurrence. Schopfaspis granulosus faunule. Rare 

(two pygidia), USGS colln. 6325-CO, boulder from 

moraine, Mount Spann.

Family JAKUTIDAE Suvorova 

Genus BATHYURISCELLUS Lermontova

Bathyuriscellus Lermontova, 1951b, p. 102; Suvorova, 1960b, 

p. 94; Suvorova and 'Chernysheva, 1960, p. 72; Chernysheva, 1961, p. 68; L. N. Repina, in Repina and others, 

1964, p. 290; Lazarenko, 1964, p. 203.

Type species. Bathyuriscellus robustus Lermontova, 

1951b, p. 103, pi. 14, figs. 2-2a.

Discussion. This genus is well described and discussed by Suvorova (1960b) and Chernysiheva (1961). 

One of the principal features that distinguishes species 

of Bathyuriscellus from those of Jakutus (Lermontova. 

1951b, p. 105) is their relatively narrow fixed cheeks 

I have examined replicas of the type species of both 

Bathyuriscellus and Jakutus. Although the cranidial 

proportions of both Antarctic species described below 

are most like those of B. robustus Lermontova, their 

ornamentation of terrace lines on the border and granules on the remainder of the cranidium is most like

that of Jakutus quadriceps Lermontova. Other species 

of Bathyuriscellus, such as B. firmus Ogienko, have 

granular ornamentation, however, so that the ornamentation of the Antarctic species merely serves to emphasize the close relationship between the genera. The relationship is further emphasized by the remarkable 

similarity in detail between the structure of the ocular 

ridge of B. modestus n. sp. and the type species of 

Jakutus, J. quadriceps Lermontova.

Except for the relatively narrow fixed cheeks, which 

the Russian workers consider to be a significant character, the Antarctic species could be assigned to either 

Jakutus or Bathyuriscellus. Perhaps the validity of the 

characters used to distinguish these genera should be 

reevaluated. According to the criteria presently in use, 

however, the Antarctic species conform in all critical 

features to Bathyuriscellus.

Bathyuriscellus australis n. sp. 

Plate 2, figures 6-10

Description. Cranidium, exclusive of posterior 

limbs, elongate, subquadrate, anterior margin gently 

rounded, gently convex transversely, moderately convex longitudinally. Glabella elongate, very slightly 

tapered forward, bluntly rounded at front, axial part 

reaches to border furrow, basal glabellar width about 

three-fourths glabellar length exclusive of occipital 

ring. Glabellar furrows broad, shallow, barely apparent. Occipital furrow straight, narrow, shallow on axial 

line, deeper towards axial furrows. Occipital ring gently 

convex in profile, upsloping; median node present at 

posterior margin. Brim absent in front of glabella. 

Border well defined by shallow, slightly curved border 

furrow, gently convex in sagittal profile; sagittal length 

between one-fourth and one-fifth sagittal glabellar 

length exclusive of occipital ring.

Fixed cheeks horizontal, gently convex; width slightly more than one-fourth basal iglabellar width. Ocular 

ridge poorly defined, directed strongly posterolaterally 

from anterior end of glabella, imperceptibly merged 

with palpebral lobe. Palpebral lobe poorly defined by 

palpebral furrow, crescentic; midlength slightly posterior to glabellar midlength; exsagittal length about 

four-ninths of sagittal glabellar length exclusive of 

occipital ring.

Posterior limb moderately short, sharply-pointed; 

transverse length slightly less than basal glabellar 

width. Posterior border furrow moderately broad and 

deep.

Course of anterior section of facial suture very slightly divergent forward in gentle curve from palpebral 

lobe to border furrow, then turned diagonally inward 

across border to intersect anterior margin distal to for-
D20 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

ward projection of anterolateral corners of glabella. 

Course of posterior section sigmoid, intersects posterior 

margin at acute angle.

Free cheek subtriangular, lateral margin gently 

curved, continuous with short, sharp, broad-based genal 

spine. Lateral and posterior border furrows merged in 

a sharp curve at genal angle. Border gently convex in 

profile; width constant, at anterior end about threefourths length of anterior section of facial suture. Distance from tip of genal spine to intersection of posterior section of facial suture with posterior margin 

slightly more than one-half length of posterior section 

of facial suture.

Pygidium, thorax, and hypostome not known.

Ornamentation on the glabella, lateral parts of the 

brim, inner part of the border, fixed cheeks and posterior 

limbs, exclusive of furrows and edges of palpebral lobes, 

consists of closely packed granules that merge with each 

other so that with some lighting the surface appears 

coarsely pitted. The outer half to three-fourths of the 

border on both the canidium and the free cheek bears 

a strong terrace ornamentation, and the areas between 

the terrace lines are pitted. The ocular platform and 

genal spine are covered with closely spaced, but distinct, 

granules.

Discussion. This species has the general cranidial 

proportions of several Siberian species 'of BathyurisceUus, such as B. robustus Lermontova, B. grandis 

Suvorova, and B. firmus Ogienko. It differs from these 

and all other species assigned to the genus by having 

short genal spines and by its unusual granular-pitted 

ornamentation. The anterior sections of the facial sutures are slightly less divergent forward than most described species of Bathyuriscellus.

None of these differences are great enough to warrant 

separation of B. australis at the generic level from the 

Siberian species of Bathyuriscellus. Ornamentation and 

the structure of the ocular ridge are the principal features that distinguish this species from the other Antarctic species, B. modestus n. sp.

Occurrence. Chorbusulina wilkesi faunule. Moderately rare (seven cranidia, one free cheek), USGS colln. 

5937-CO, 6308-CO, boulders from moraine on Mount 

Spann.

Bathyuriscellus modestus n. sp.

Plate 2, figures 16, 17

Description. The general morphology of the cranidium of this species is essentially the same as that of 

B. australis except for the structure of the ocular ridges 

and the cranidial ornamentation. Because of this, only 

these features are separately described.

Ocular ridges poorly defined, directed strongly posterolaterally from anterior end of glabella; axial end 

bifurcated by shallow furrow, and the anterior part of 

this ridge forms a sinuous structure that wraps around 

the anterolateral corner of the glabella and extends inward nearly to the axial line, separating the glabella 

from the border furrow.

Ornamentation consists of low granules on a,ll convex 

parts except the border and the palpebral lobe. There 

is a tendency for some 'of the granules to merge and 

form short variously oriented sinuous segments of 

ridges on the top of the glabella. The border and palpebral lobes have low terrace lines. The exoskeleton between the granules 'and terrace lines has scattered tiny 

pits.

Discussion. The features described above distinguish this species from all other species of Bathyuriscellus. The structure of the ocular ridges is essentially 

the same as it is for the specimen of Jakutus quadriceps 

figured by Lermontova (1951t>, pi. 15, fig. Ic) of which 

I have a replica.

Occurrence. Chorbusulina, subdita faunule. Rare 

(one oranidium), USGS colln. 6312-CO, boulder from 

moraine on Mount Spann.

Family OBTCTOCEPHAIJDAE Beecher

Genus GOLDFIELDIA Palmer 

Goldfieldia Palmer, 1964, p. 7.

Type species. Goldfieldia pacifica Palmer, 1964, p. 7, 

pi. 1, £.gs. 14,16-18.

Diagnosis. "Oryctocephalidae which have glabella 

poorly defined at front, narrowest at occipital ring; 

frontal lobe with median depression in anterior part. 

Posterior pair of glabellar furrows connected laterally 

to axial furrows. Anterior cranidial border wirelike" 

(Palmer, 1964, p. 7).

Discussion. Most oryctocephalid genera are widespread and have moderately long stratigraphic ranges. 

Goldfieldia is no exception. The Antarctic species described below conforms in all respects to the generic 

diagnosis just cited, which was based on a single species 

from Lower Cambrian beds in Nevada. The Antarctic 

occurrence greatly extends the geographic range of 

G-oldfieldia. The stratigraphic range is also extended 

because the Antarctic species appears +o be in an early 

Middle Cambrian assemblage.

Goldfieldia ninguis n. sp.

Plate 3, figures 7, 8

Description. Oryctocephalidae which have cranidium subtrapezoidal in outline, gently convex transversely, moderately convex longitudinally; width 

between anterior sections of facial sutures about three-
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D21

fourths width between tips of posterior limbs. Anterior 

margin gently curved.

Glabella well defined at sides; axial furrows shallow, 

subparallel between preoccipital and occipital furrows; 

divergent slightly forward between preoccipital and 

second glabellar furrows and then continued nearly 

straight forward to junction with ocular ridge. Anterior 

end of glabella defined laterally by change o<f slope, not 

defined at front, reaches nearly to narrow wirelike border. Brim, lateral to glabella, gently concave. Four pairs 

of lateral glabellar furrows present but not connected 

across top of glabella; posterior and anterior pairs connected laterally to axial furrows; middle two pairs are 

transversely elongate pits. Frontal glabellar lobe has 

shallow median depression on anterior part. Occipital 

furrow shallowest on axial line, moderately deep, narrow, 'adjacent to axial furrows.

Fixed cheek gently convex, slightly downsloping; 

width, exclusive of palpebral lobes about equal to basal 

glabellar width. Palpebral lobe well defined by sharp 

change in slope, slightly curved; exsagittal length 

slightly less than basal glabellar width; line connecting 

posterior tips passes over preoccipital furrow. Ocular 

ridge poorly defined, reaches axial furrow about opposite anterior glabellar furrow.

Posterior limbs bluntly rounded; transverse length 

about 1.1/2 times basal glabellar width. Posterior border 

furrow moderately deep except at tip of limb and near 

axial furrow.

Course of anterior section of facial suture nearly 

straight forward from palpebral lobe to anterior margin. Course of posterior section of facial suture moderately to strongly convex; strongly divergent 

immediately behind palpebral lobe.

Eternal surfaces of all parts of cranidium smooth.

Other parts not known.

Discussion. This species is remarkably similar to 

the type species, G. pacifica Palmer from Lower Cambrian beds of Nevada. The principal differences are the 

more slotlike middle glabellar furrows and slightly 

shorter palpebral lobes and posterior limbs.

Occurrence. Xystridura multilinia faunule. Rare (6 

cranidia), USGS colln. 6333-CO, boulder from moraine 

on Mount Spann.

Order PTYCHOPARHDA Swinnerton 

Family ANOMOCARIDAE Poulsen

Genus CHONDRANOMOCARE Poletaeva

Chondranomocare Poletaeva, 1956, p. 169; Yegorova and others, 

1960, p. 214 ; Chernysheva, 1961, p. 196.

Type species. Chondranomocare bidjensis Poletaeva, 

L956, p. 170, pi. 31, figs. 4,5. 

Discussion. A good diagnosis of this genus with a

discussion of its relations to other genera is given by 

Chernysheva (1961). The combination of a long, gently 

tapered, poorly furrowed glabella that is bluntly 

rounded anteriorly, narrow fixed cheeks, short brim, 

and broad concave border distinguishes cranidia of this 

genus from all others. The concave rather than flat or 

convex border distinguishes Chondranomocare from 

Pseudanomocarina.

Pygidia are generally transversely subovate and have 

several ring furrows on the axis and several pleural or 

interpleural furrows on the pleural regions. The margin 

lacks spines.

Chondranomocare is known at present only from the 

Amga Stage of early Middle Cambrian age in many 

parts of Siberia.

Chondranomocare australis n. sp. 

Plate 3, figures 18-24

Description. Cranidium elongate, subquadrate, 

gently rounded anteriorly; length slightly greater than 

width between palpebral lobes. Glabella long, gently 

convex transversely and longitudinally, tapered slightly 

forward, bluntly rounded anteriorly; moderately well 

defined at sides by shallow axial furrows, defined at 

front by abrupt change in slope. Glabellar furrows shallow to not apparent; posterior pair directed strongly 

backward from axial furrows. Occipital furrow very 

shallow on axial line, moderately deep near axial furrow. Occipital ring flat or slightly convex; small median 

axial node present. Frontal area gently concave, slightly 

downsloping. Brim narrow, separated from border by 

poorly developed border furrow that is barely apparent 

on larger cranidia. Border weakly concave in front of 

glabella, nearly flat laterally; sagittal length slightly 

more than twice sagittal length of brim.

Fixed cheek narrow, gently convex, horizontal; width, 

exclusive of palpebral lobes, about one-fourth basal 

glabellar width. Palpebral lobe strongly arcuate, both 

ends near axial furrows; palpebral furrow shallow, 

parallel to lobe margin; exsagittal length of palpebral 

lobe slightly more than one-half sagittal glabellar length 

exclusive of occipital ring. Short poorly defined ocular 

ridge connects palpebral lobe to glabella well back of 

anterior end.

Posterior limb slender, short, sharply pointed; transverse length about two-thirds basal glabellar width. 

Posterior border furrow shallow, straight.

Course of anterior section of facial suture strongly 

divergent forward to sharply rounded anterolateral 

corners of cranidium. Course of posterior section 

sinuous.

Free cheek has gently curved lateral margin. Ocular 

platform gently convex. Border flat, defined by shallow
D22 'CONTRIBUTIONS TO THE GEOLOGY OP ANTARCTICA

lateral border furrow that joins posterior border furrow in sharp curve at genal angle; width at anterior 

sutural margin about half width of ocular platform. 

Genal spine flat, sharply pointed; length from tip to 

posterior sutural margin about iy2 times length of posterior section of facial suture.

Pygidium transversely subovate, lateral margins 

sharply curved; length about one-half greatest width. 

Posterior margin evenly curved, nonspinose. Axis well 

defined at sides by abrupt change in slope, tapered 

slightly backward, bluntly rounded at rear, merged 

posteriorly with border. Two shallow ring furrows present posterior to articulating furrow. Pleural regions 

gently convex; border poorly denned, downsloping, 

about as wide as greatest width of pleural platform. 

Pleural platform and inner part of border crossed by 

three interpleural furrows; posterior furrow much shallower than anterior furrows; depth of all furrows decreases abruptly at inner margin of border.

External surfaces of pygidial axis, posterior part of 

glabella, and borders on cranidium, free cheek, and 

pygidium are covered with very fine low granules apparent only after whitening. Surfaces of all other parts 

smooth.

Discussion. The pygidial structure, structure of the 

frontal area, and ornamentation are the most distinctive characters of O. australis. This species differs from 

all described species of Chondmnomocare by having a 

weakly concave cranidial border and a poorly developed 

anterior border furrow. Pygidia are known for only 

two species of Chondmnomocare. The pygidia of O. 

australis lack the development of interpleural furrows 

that characterizes C. speciosum Romanenko (Yegorova 

and Savitskiy, 1969, pi. 39, figs. 17-21), and they have 

one less pleural furrow and two less ring furrows than 

C. exilis Yegorova (Yegorova and Savitskiy, 1969, pi. 

40, figs. 6-13).

Occurrence. Amphoton oatesi faunule. Moderately 

common (six cranidia, one free cheek, eight pygidia), 

USGS colln. 4446-CO, Nelson Limestone, Neptune 

Kange.

Family ASAPHISCIDAE 

Genus LIOPEISHANIA Chang 

Liopeishania Chang, 1963, p. 486.

Type species. Psilaspisf convexus Endo and 

Eesser, 1937, p. 350, pi. 59, figs. 1-4.

Diagnosis. Asaphiscidae having glabella poorly defined on external surface; glabellar furrows absent; 

occipital furrow shallow. Brim and fixed cheeks downsloping, nearly continuing curvature of glabella. Anterior border distinctly defined by abrupt change in 

slope. Fixed cheeks about one-half basal glabellar width.

Palpebral lobes situated about opposite glabellar midlength, poorly defined on external surface. Posterior 

limbs shorter than basal glabellar width; posterior 

border furrow shallow.

Free cheek narrow, lateral border poorly defined. 

Genal spine absent.

Pygidium semicircular. Axis narrower than pleural 

regions, tapered slightly, strongly rounded at rear, not 

extended to posterior margin. Border narrow, poorly 

defined. Axial and pleural furrows absent on external 

surface.

Surfaces of all parts smooth.

Discussion. Cranidia of the Antarctic species described below conform to the diagnosis of this genus 

given by Chang (1963) based only on cranidia. Yegorova (written commun., 1970) reported that in 1965, 

Chang included Peishania lubrica (Chang, 1959, p. 

234, pi. 4, figs. 7-11) in Liopeishania in a Chinese book, 

"Trilobites in China", that is not available to me. The 

Antarctic species is so similar to L. lubrica (Chang) 

that the diagnosis of the genus is expanded here to include information about the free cheek and pygidium 

based on the Antarctic material.

Liopeishania spannensis n. sp. 

Plate 4, figures 9,10,14-22

Description. Cranidium subtrapezoidal, anterior 

margin moderately rounded. Sagittal length about 

three-fourths width between tips of posterior limbs. 

Only posterior part of glabella defined on external 

surface by faint change in slope apparent only after 

whitening; entire glabella defined on mold, tapered 

forward, sharply rounded anteriorly, gently convex 

transversely and longitudinally, slides opposite palpebral lobes have slight short outward bulge. Occipital 

ring barely differentiated on external surface. Frontal 

area subsequently divided into brim and border. Brim 

continues downward curvature of front of galbella and 

is separated from border by strongly curved change in 

slope so that outer part of border is nearly horizontal 

and at distinct angle to brim. Small cranidia (pi. 4, fig. 

16) have glabella better defined and a median longitudinal depression on brim.

Fixed cheek downsloping, gently convex, continuing 

lateral curvature of glabella; width, including palpebral lobes, one-half or slightly less than one-half basal 

glabellar width. Palpebral lobe not defined by palpebral 

furrow, differentiated only by slight change in slope; 

situated opposite middle third of glabella; exsagittal 

length slightly less than one-fourth sagittal length of 

cranidium. Ocular ridges narrow, apparent only on surface of mold.

Posterior limb short, bluntly rounded; transverse
EARLY AND MIDDLE CAMBRIAN TRJILOBITES FROM ANTARCTICA D23

length about one-half basal glabellar width. Posterior 

border furrow not defined on external surface.

Course of anterior section of facial suture slightly 

convergent forward from palpebral lobe to border, 

then curved inward across margin; distance between 

intersections with margin about equal to basal glabellar 

width indicating moderately wide (transverse) rostral 

plate. Course of posterior section of facial suture directed outward behind palpebral lobe, then strongly 

curved backward to intersect posterior margin 

perpendicularly.

Free cheek narrow. Lateral border defined only in 

anterior part. Lateral margin evenly curved, genal angle 

strongly rounded. Border about equal in width to ocular platform.

Pygidium semicircular, moderately convex transversely; sagittal profile straight over axis, depressed 

posterior to axis. Axis defined only by change in slope, 

not furrowed on external surface, bluntly rounded posteriorly. Pleural regions smooth, convex, downsloping 

laterally; border not differentiated from pleural platform. Mold shows three or four shallow ring furrows 

posterior to articulating furrow and three or four pleural-interpleural furrow pairs on the pleural platform 

and inner part of border posterior to anterior pleural 

furrow. Border poorly defined, maintains nearly constant width that is about one-half maximum width of 

pleural platform. Axis reaches to inner margin of 

border.

External surfaces of all parts smooth, except for anterior part of cranidial border and anterolateral pygidial margins which have low terrace lines. Anterolateral 

facets of pygidium project slightly laterally beyond 

pygidial margin and have very faint granules on some 

specimens. Surfaces of mold coarsely pitted.

Discussion. This species is extremely similar to Liopeishania lubrica (Chang, 1959) from the Peishania 

zone of the Changhsia Formation in Shantung, China. 

The species are almost certainly congeneric, and the differences between them, based only on comparison with 

Chang's photographs and brief description, are minor.

L. spannensis has an occipital ring that is nearly uniform in breadth, whereas the occipital ring of L. lubrica 

is triangular. The pygidial border on L. spannensis 

seems to be narrower than that of L. lubrica. The 

validity of these apparent differences can only be determined by comparison of actual specimens. Until this 

can be done, the Antarctic specimens are considered to 

represent a species distinct from L. lubrica.

Occurrence. Schopfaspis granulosus faunule. Common (40 cranidia, pygidia, and free cheeks), USGS 

colln. 6313-CO, 6325-CO, 6327-CO, 6364-CO, boulders 

from moraine on Mount Spann.

Family CONOKEPHALHTIDAE Hup6 

Genus STILUDELLA Yegorova and Savitskiy 

Sitdudella Yegorova and Savitskiy, 1968, p. 64; 1969, p. 213.

Type species. Suludella solita Yegorova and Savitskiy, 1968, p. 64, pi. 10, fig. T.

Discussion. This genus is well characterized, with 

good illustrations of several species, by Yegorova and 

Savitskiy (1969). It includes trilobites that have cranidia with an anteriorly tapered, bluntly rounded, poorly furrowed glabella; a flat or concave border as wide 

or wider than the brim; anteriorly flared facial sutures; 

long arcuate palpebral lobes; and fixed cheeks one-third 

to one-half of the glabellar width. Pygidia are relatively 

small, with several axial and pleural furrows and with 

short anterolateral spines.

The Antarctic species described below are only questionably assigned to Suludella^ because the palpebral 

lobes are longer and more posteriorly placed than in 

the illustrated species of Suludella. Cranidia, without 

the associated pygidia, might be placed in GJiondranomocarej except that the fixed cheeks are wider than 

other species of that genus, and the inner ends of the 

palpebral lobes are farther from the glabella. Also, if 

the pygidial association is correct, the large axis and 

spinose margin are unlike all species of Ckondranomocare.

Suludella? davnii n. sp.

Plate 6, figures 1,2,5

Description. Cranidium subquadrate, anterior margin gently rounded; length slightly greater than width 

across palapebral lobes. Glabella gently convex transversely and longitudinally, tapered slightly forward, 

bluntly rounded anteriorly, moderately well defined 

at sides by shallow axial furrows, poorly defined at 

front by very shallow preglabellar furrow. Glabellar 

furrows barely apparent. Occipital furrow deep only 

near axial furrow, shallow across axis. Occipital ring 

gently convex, bears median axial node. Frontal area 

concave; sagittal length about one-half sagittal length 

of glabella exclusive of occipital ring. Brim flat, downsloping, separated from border by shallow border furrow. Border concave; sagittal length slightly more than 

twice sagittal length of brim.

Fixed cheeks gently convex, slightly upsloping; 

width, exclusive of palpebral lobes, about two-fifths 

basal glabellar width. Palpebral lobes strongly arcuate, 

moderately well defined by shallow palpebral furrow; 

exsagittal length about three-fourths lengths of glabella exclusive of occipital ring.

Posterior limb not known.

Course of anterior section of facial suture strongly 

divergent forward from palpebral lobe to strongly
D24 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

rounded anterolateral corners of cranidium. Course 

of posterior section not known.

Free cheek has evenly curved lateral margin. Genal 

spine slightly concave on proximal part; length from 

tip to posterior suture slightly greater than length of 

posterior section of facial suture. Ocular platform 

gently convex. Border concave, well defined by shallow 

lateral border furrow that meets posterior border furrow at sharp curve at genal angle. Width of border at 

anterior margin about half anterior width of ocular 

platform.

Pygidium known only from fragment of pleural 

region. Border gently concave, downsloping, separated 

from pleural field by slight change in slope; width 

about equal to greatest width of pleural platform. Short 

anterolateral spine present. Pleural field and inner 

part of border crossed by four pleural furrows that 

have distinct geniculation at inner edge of border. Posterior furrow very shallow, other furrows moderately 

deep.

External surfaces of all parts covered with fine, 

closely spaced granules apparent only after whitening.

Discussion. This species differs from all others in 

Suludella by having a line connecting the posterior tips 

of the palpebral lobes passing nearly over the occipital 

furrow rather than distinctly anterior to the furrow, 

and by having a considerably narrower brim. The cranidium is very similar to that of S.f spinosa n. sp., from 

which it differs by having a slightly wider brim and a 

more concave border on the free cheek. The pygidium 

has only one pair of short anterolateral spines, thus 

being more typical of Suludella, whereas S.f spinosa 

has several pairs of short spines.

Occurrence. Solenopleura pruina faunule. Moderately common (three cranidia, 10 free cheeks, one 

fragmentary pygidium), USGS colln. 6320-CO, boulder from moraine, Mount Spann.

Suludella? spinosa n. sp. 

Plate 6, figures 16-18, 20-23

Description. Cranidium subquadrate, gently convex 

transversely and longitudinally gently rounded anteriorly, width between palpebral lobes distinctly greater 

than length. Glabella low, well defined at sides by 

abrupt changes in slope of exoskeleton or by shallow 

axial furrows present only along midlength of sides; 

tapered slightly forward, bluntly rounded anteriorly. 

Anterrior end poorly defined. Glabellar furrows shallow, narrow, posterior pair directed posteriorly. Occipital furrow deep at glabellar sides, shallow across midline. Occipital ring simple. Frontal area short, concave, 

divided by shallow border furrow with slight median 

posterior inflection into broad, concave border and

extremely narrow brim. Sagittal length of frontal area 

about three-eight's sagittal glabellar length exclusive 

of occipital ring; sagittal length of border about threefourths sagittal length of frontal area.

Fixed cheek gently convex, flat or slightly upsloping; 

width, exclusive of palpebral lobe, about two-fifths basal 

glabellar width. Palpebral lobe long, strongly arcuate, 

continuous with short ocular ridge; situated opposite 

posterior half of glabella; exsagittal length slightly less 

than one-half sagittal glabellar length exclusive of occipital ring.

Posterior limb slender, length not known.

Course of anterior section of facial suture directed 

strongly anterolaterally from palpebral lobe to 

sharply curved anterolateral corner of cranidium. 

Course of posterior section divergent-sinuous.

Free cheek has gently curved lateral margin and 

flat genal spine of unknown length. Border flat, defined 

by shallow lateral border furrow that meets posterior 

border furrow at sharp angle near base of genal spine. 

Posterior border furrow deeper than lateral border furrow, continued as shallow furrow onto genal spine. 

Width of border at anterior sutural margin about twothirds width of ocular platform.

Pygidium subovate, moderately to strongly convex 

transversely and longitudinally. Axis high, tapered 

posteriorly to point nearly above posterior margin, 

bluntly rounded at back; width about equal to width of 

pleural platform. Two or three ring furrows present 

posterior to articulating furrow; anterior two furrows 

deepest. Pleural regions gently convex, downsloping; 

crossed by two or three moderately deep pleural furrows 

that continue onto narrow poorly defined border. Two 

shallow diagonal interpleural furrows are present on 

pleural platforms only. Border narrow, tapered towards 

axis, bears five pairs of short, sharp, slender spines.

Axial part of glabella and pygidium, outer part of 

border on cranidium, free cheek, and pygidium including spines covered with closely spaced coarse granules. 

Fixed cheek and ocular platform of free cheek have less 

dense covering of granules. Brim, inner parts of border 

on cranidium and free cheek, part of ocular platform, 

and all of pleural platform of pygidium lack distinct 

ornamentation.

Discussion. This species is assigned to Suludella because of the general cranidial characters and the presence of a narrow border and relatively large furrowed 

axis on the pygidium. The assignment is questioned because the palpebral lobes are more posteriorly situated 

than those of the Siberian species, and the pygidium has 

a multispinose margin. These characters distinguish 

S.f spinosa from all other species in the genus.

The association of pygidium and cranidium is based
EARLY AND MIDDLE CAMBRIAN TRTLOBITES FROM ANTARCTICA D25

on their presence in two collections, from localities 

more than 100 miles apart, in which they occur with 

only one other common trilobite, Nelsonia schesis n. sp. 

The style of ornamentation, with granules principally 

on the axial parts and the outer margins, supports the 

association.

Occurrence. Nelonia schesis faunule. Moderately 

common (10 cranidia, one free cheek, six pygidia), 

USGS colln. 4443-CO, 6378-CO, 6379-CO, 6380-CO 

Nelson Limestone, Neptune Kange; 6355-CO, boulder 

from moraine on Mount Spann.

Family NEPEIDAE Whitehouse 

Genus TRINEPEA n. gen.

Type species. Trinepea trinodus n. sp.

Diagnosis. Nepeidae with three prominent bosses on 

brim; wide, upsloping fixed cheeks; prominent undivided ocular ridges; palpebral lobes opposite anterior 

third of glabella; and large backwardly flared posterior 

limbs.

Discussion. Opik (1963, 1967) has provided good 

discussions of the character and content of the Nepeidae. 

All genera in the family are characterized by a median 

boss on the brim. Trinepea differs from all other nepeids 

and alll other Cambrian trilobites by having a pair of 

prominent lateral bosses on the brim as well as the 

median boss. It also lacks a divided ocular ridge that is 

stated by Opik (1963, p. 340) to be typical of all nepeids. 

However, in view of the great majority of characters 

shared with Nepea and other nepeids, this difference is 

considered here to be of no more than generic 

importance.

Trinepea trinodus n. sp.

Plate 4, figures 1, 2

Description. Cranidium trapezoidal, moderately 

rounded anteriorly; sagittal length slightly more than 

half of width between tips of posterior limbs. Glabella 

prominent, slightly sunken, moderately tapered forward, truncate anteriorly, gently convex transversely, 

moderately convex longitudinally, well defined by deep 

axial and preglabellar furrows; sagittal length, exclusive of occipital ring, about equal to basal glabellar 

width. Three pairs of short deep lateral g'labellar furrows indent lateral glabellar margin at axial furrow; 

posterior pair longest, directed strongly backward. Posterior glabellar lobes extended laterally onto inner part 

of fixed cheeks. Occipital furrow deep adjacent to axial 

furrow, shallow across axis. Structure of occipital ring 

not known. Frontal area consists of broad moderately 

convex brim and narrow gently convex border, separated by broad deep border furrow; sagittal length 

frontal area about equal to sagittal length of glabella

exclusive of occipital ring; sagittal length of border 

about one-fourth sagittal length of brim. Brim has three 

large poorly defined bosses, one at midlength on axial 

line and others lateral to this and slightly closer to the 

facial suture than to the median boss.

Fixed cheek wide, upsloping; width, exclusive of 

palpebral lobe, about equal to basal glabellar width. 

Palpebral lobe short, sharply arcuate, well defined by 

broad palpebral furrow, connected to front of glabella 

by straight, nearly transverse, narrow well-defined undivided ocular ridge; exsagittal length of palpebral 

lobe slightly more than one-half sagittal glabellar 

length exclusive of occipital ring.

Posterior limb long, broad; downsloping lateral to 

palpebral lobe and posterior border strongly backswept. 

Posterior border furrow nearly straight, transverse, 

deep, broadens distally. Transverse length of posterior 

limb slightly more than iy2 times basal glabellar width.

Course of anterior section of facial suture nearly 

straight forward from palpebral lobe to anterior margin, further course not known. Course of posterior section of facial suture almost straight laterally from 

palpebral lobe, then curved strongly backward to posterior margin.

External surfaces of all convex parts covered with 

coarse granules. Furrows and extension of posterior 

glabellar lobe onto fixed cheek smooth.

Free cheek, thorax, and pygidium not known.

Discussion. This striking species, although represented by only two cranidia, is so unusual that it cannot 

be closely compared with any other described Cambrian 

trilobite. Both cranidia are quite large (length 12 to 14 

mm). An associated nepeid cranidium about one-third 

as large has only a median boss on the brim. This small 

specimen may be a younger individual on which the 

lateral bosses have not developed, but there is no indication of even incipient development, and it is recorded 

here as a separate, unnamed, nepeid (p. D32).

Occurrence. Amphoton oatesi faunule. Rare (two 

cranidia), 1780*8 colln. 4446-CO, Nelson Limestone, 

Neptune Range.

Family SOLENOPLEURIDAE Angelin 

Genus SOLENOPLETJRA Angelin

Solenopleura Angelin, 1854, p. 26; Lake 1931, p. 133; Kobayashi 

1935, p. 262; Westergard, 1953, p. 7; Chernysheva, 1953, 

p. 34; Yegorova and others, 1960, p. 231; Chernysheva, 

1961, p. 242.

Type species Calytnene canaliculata Angelin, 1851, 

p. 23, pi. 18, figs. 9,9a.

Discussion. Westergard (1953) and Chernysheva 

(1953) both give excellent summaries of the characters 

of this genus. Westergard points out that the correct
D26 'CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

type species is /S. canaliculata and not S. holometopa 

and compares all the Scandinavian species. Chernysheva 

tabulated the characters of eight Russian species in addition to her diagnosis of the genus.

/Solenopleura, as presently constituted, includes a 

variety of ptychoparioids that have a well-defined anteriorly tapered strongly rounded glabella, well-defined 

border, moderately wide fixed cheeks, generally small 

palpebral lobes variously situated with respect to the 

glabellar midlength, free cheeks with variably developed and directed genal spines, nonspinose pygidia 

with a variable number of axial and pleural segments 

and a generally granular ornamentation.

The Antarctic species seems closest in overall characters to the Siberian species described and illustrated by 

Chernysheva. They share relatively wide fixed cheeks 

and small upturned palpebral lobes on the cranidium, 

a pygidium with few axial and pleural furrows, and 

granular ornamentation. The Scandinavian species included in Solenopleura have a greater variety of craiiidial and pygidial characters, and none of the species 

closely resembles the Antarctic species.

Solenopleura pruina n. sp. 

Plate 5, figures 19-22

Description. Cranidium subquadrate, gently convex 

transversely, moderately convex longitudinally, moderately rounded anteriorly; length slightly less than 

width between palpebral lobes. Glabella well defined by 

deep axial and moderately shallow preglabellar furrows, 

moderately convex transversely and longitudinally, 

tapered forward, strongly rounded at front; length, 

exclusive of occipital ring, about equal to width. Glabellar furrows barely apparent. Occipital furrow straight, 

moderately deep. Occipital ring moderately convex, 

without occipital spine; width uniform. Frontal area 

includes strongly downsloping, gently convex brim and 

nearly horizontal gently convex border separated by 

broad shallow border furrow; sagittal length of brim 

about one-fourth sagittal length of glabella exclusive of 

occipital ring; sagittal length of border slightly less 

than three-fourths sagittal length of brim.

Fixed cheek gently convex, horizontal; width, exclusive of palpebral lobe, about one-half basal glabellar 

width. Palpebral lobe small, upturned, connected to anterolateral end of glabella by narrow, poorly defined 

ocular ridge, situated opposite middle third of glabella; 

exsagittal length slightly less than one-third sagittal 

glabellar lentgh exclusive of occipital ring.

Posterior limb blunt, transverse length about twothirds basal glabellar width. Posterior border furrow 

deep, straight.

Course of anterior section of facial suture slightly

divergent forward to strongly rounded anterolateral 

cranidial corners. Course of posterior section convex, 

intersects posterior margin nearly perpendicularly.

Free cheek has narrow, convex border defined by 

deep lateral border furrow that becomes shallow towards genal angle; width of border about two-thirds 

width of gently convex ocular platform along anterior 

sutural margin. Lateral margin gently curved, continuous with margin of moderately short sharp genal spine; 

distance from tip of spine to posterior facial suture 

about four-fifths length of posterior section of facial 

suture. Posterior suture intersects margin near base of 

genal spine.

Pygidium transversely subovate, lateral margins 

sharply rounded, posterior margin gently rounded, 

without spines. Axis prominent, broad, barely tapered, 

bluntly rounded posteriorly, reaches to inner edge of 

narrow poorly defined border; width slightly greater 

than width of pleural region. One or two ring furrows, 

present posterior to articulating furrow; anterior furrow deepest. Pleural regions gently convex, crossed by 

two or three broad shallow pleural furrows that reach 

to inner edge of a narrow border that is defined only 

by slight change in slope of pleural region.

External surfaces of all parts except glabellar and 

axial furrows, and palpebral lobes, covered with closely spaced fine granules; glabellar lobes, fixed cheeks, 

and brim on the cranidium and ocular platform on free 

cheek also have scattered larger granules.

Discussion. This species differs from the several 

Russian species of /Solenopleura described by Chernysheva (1953), with which it shares more characters 

than it does with the Scandinavian species described by 

Westergard (1953), by having narrower fixed cheeks 

than all but /S. zverewi Lermontova. The axis of the 

pygidium of the Antarctic species does not reach the 

posterior margin as it does in S. sverewi.

Occurrence. Solenopleura pruina faunule. Moderately common (seven cranidia, four free cheeks, four 

pygidia), USGS colln. 6320-CO, boulder from moraine, 

Mount Spann.

UNASSIGNED TRILOBITES 

Genus GLABRELLA Lermontova

Glabrella Lermontova, 1940, p. 120; Lermontova, 1951a, p. 28; 

Repina, 1960, p. 157; Yegorova, 1962, p. 158.

Type species. Gldbrella ventrosa Lermontova, 1940, 

p. 120, pi. 35, figs. 9,9a-d.

Discussion. This genus was proposed by Lermontova for small Middle Cambrian trilobites that lacked 

differentiation of the glabella and border on the cranidium. Yegorova (1962) included an Early Cambrian 

species that differed from the type species by lacking
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D27

the upturned palpebral lobes and by having the longitudinal profile of the cranidium more evenly curved. 

The Antarctic species described below is most like 

Grlabrella mrassina Yegorova, the only obvious difference being ornamentation. However, the description of 

that species is brief and the illustration is not clear so 

that other possible differences cannot be determined. 

The contrast in structure of the palpebral lobes and in 

the longitudinal profile between Gf. mrassina and the 

type species, G. ventrosa, suggests that they may be 

quite unrelated trilobites that have been grouped primarily because they both lack development of most 

cranidial furrows. For this reason, the generic assignment of the Antarctic species is questioned.

All Russian workers have included Grlabrella in the 

Pagetiidae. The structure of the palpebral lobe, course 

of the facial sutures, and breadth of the glabella for 

Gr. mrassina are all unlike any described pagetiids, and 

if the affinities to O. pitans n. sp. are real, this trilobite 

is an effaced ptychoparioid trilobite rather than a 

pagetiid trilobite. Without the opportunity to examine 

specimens of the type species of Gldbrella, this is further reason to question the assignment of the Antarctic 

species to this genus.

Glabrella? pitans n. sp. 

Plate 1, figures 9,10,13,14

Description. Cranidium subquadrate, moderately 

convex transversely and longitudinally; width between 

palpebral lobes slightly greater than length. Glabella 

not differentiated on external surface, barely recognizable even on surface of mold, low, tapered forward, 

strongly rounded anteriorly. Glabellar furrows absent. 

Occipital furrow extremely weak, barely apparent on 

many specimens. Occipital ring continues convexity of 

glabella. Frontal area not differentiated into brim and 

border, downsloping, continues anterior curvature of 

glabella; sagittal length about one-fourth sagittal 

length of glabella including occipital ring.

Fixed cheek gently convex, downsloping, continues 

lateral curvature of glabella; width, including undifferentiated palpebral lobe about three-fourths basal glabellar width. Very faint posterolateral ridges apparent on 

some specimens. Palpebral lobe situated opposite cranidial midlength, gently curved, not defined by palpebral furrow; exsagittal length about one-fourth sagittal 

length of cranidium.

Posterior limb short, blunt; transverse length about 

three-fourths basal glabellar width. Posterior border 

furrow shallow, divergent laterally from posterior 

margin.

Course of anterior section of facial suture nearly 

straight forward from palpebral lobe to moderately

rounded anterolateral cranidial margin. Course of 

posterior section convex.

Free cheek elongate, lateral margin gently curved, 

border not differentiated. Genal spine convex, broad 

based, margin slightly deflected from margin of anterior part. Distance from tip of spine to posterior section of facial suture about twice length of posterior 

section of facial suture.

Thoracic segments and pygidium not known.

Exterior surfaces of all specimens longer than 5 mm 

covered with scattered fine pits; smaller specimens are 

smooth. Terrace lines present along anterior margin 

of cranidium, posterior cranidial margin only at juncture of posterior limb and glabella, lateral margin of 

free cheek, and all of genal spine.

Discussion. The ornamentation, structure of the 

palpebral lobes, absence of almost all dorsal furrows, 

and presence of a large spine on the free cheek are the 

most characteristic features of this species that differentiate it from other smooth trilobites. The change from 

smooth to pitted ornamentation at a cranidial length 

about 5 mm is an unusual feature that may also be 

characteristic of this species. Fragments indicate that 

some specimens of this species had cranidia about 3 cm 

long.

Occurrence. Australaspis magnus f aunule. Common 

(>30 cranidia, one free cheek), USGS colln. 5939-CO, 

6311-CO, boulders from moraine on Mount Spann.

Genus Felsonia n. gen.

Type species. Nelsonia schesis n. sp.

Diagnosis. Tiny ptychoparioid trilobites. Glabella 

prominent, unfurrowed, tapered forward, well defined 

by axial and preglabellar furrows. Prominent median 

pit in preglabellar furrow on axial line. Occipital ring 

broad. Frontal area subequally divided by border furrow that is deep laterally and shallow on axial line. 

Fixed cheeks nearly flat, horizontal, wide. Palpebral 

lobes not well defined, about one-half glabellar length 

exclusive of occipital ring. Posterior limb blunt.

Course of anterior sections of facial sutures nearly 

straight forward from palpebral lobe. Course of posterior section convex, moderately divergent behind palpebral lobe.

Free cheek narrow. Border about as wide as ocular 

platform. Genal spine long, broad-based, continues curvature of margin. Most specimens retain the eye surface.

Pygidium subtriangular, strongly convex transversely and longitudinally. Axis defined only at sides, tapered 

posteriorly and sloped downward to posterior margin. 

Two ring furrows continuous across axis, one or two 

additional rings shown by furrows only at sides of axis. 

Pleural regions downsloping, crossed by four or five
D28 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

closely spaced pleural f urrow-interpleural furrow pairs. 

Border not present.

External surfaces of all parts obscurely granular.

Discussion. This distinctive little trilobite differs 

from all other ptychoparioids by the presence of a 

large deep pit in the preglabellar furrow on the axial 

line. The tendency for the free cheek to retain the visual 

surface is probably also a significant generic character.

No described trilobites can be closely compared with 

this trilobite.

Nelsonia schesis n. sp.

Plate 6, figures 3, 4, 6-14

Description. Cranidium small. Adult specimens 

rarely exceed 3 mm in length. Cranidium subquadrate, 

moderately rounded anteriorly, gently convex transversely and longitudinally; width between palpebral 

lobes slightly greater than length. Glabella prominent, 

unfurrowed, tapered forward or subparallel-sided, 

strongly rounded at front, strongly convex transversely, 

gently convex longitudinally, well defined by axial and 

preglabellar furrows. Large pit situated in preglabellar furrow on axial line. Occipital furrow deep, straight. 

Occipital ring broad; sagittal length about one-half 

sagittal length of remainder of glabella. Frontal area 

subequally divided by border furrow into convex border and nearly flat brim; sagittal length slightly less 

than one-half sagittal length of glabella exclusive of 

occipital ring. Border furrow very shallow on axial line, 

deep laterally.

Fixed cheek gently convex, slightly downsloping; 

width, including poorly defined palpebral lobe, from 

slightly more to slightly less than basal glabellar width. 

Exsagittal length of palpebral lobe about one-half or 

slightly more than one-half sagittal glabellar length.

Posterior limb blunt, transverse length equal to or 

slightly less than basal glabellar width. Posterior border furrow deep, narrow, of uniform depth.

Course of anterior section of facial suture nearly 

straight forward from palpebral lobe to moderately 

rounded anterolateral corners of cranidium. Course of 

posterior section convex, moderately divergent behind 

palpebral lobe.

Free cheek narrow, lateral margin gently curved, 

continuous with long, broad-based genal spine. Border 

convex, poorly defined by lateral border furrow; about 

as wide as ocular platform. Eye surface retained on 

most specimens, covered with obscure round facets. Distance from tip of genal spine to posterior section of 

facial suture about twice length of posterior section of 

facial suture.

Pygidium strongly convex transversely and longitudinally. Axis prominent, taipered posteriorly to margin, defined only at sides. Height decreases toward rear 

so that posterior part is barely elevated above pleural 

regions. Two ring furrows continue across axis behind 

articulating furrow. First ring furrow has crescentic 

pseudoarticulating ring on axial line. One or two additional ring furrows marked only at sides of axis. Muscle 

scars show on axis as low raised paired protuberances. 

Pleural regions not differentiated into pleural fields and 

border. Three or four pleural furrows cross pleural regions. All but anterior furrow are paired with shallow 

subparallel interpleural furrow. Posterior margin 

smooth.

External surfaces of 'all parts covered with o'bscure 

closely spaced granules.

Discussion. The distinctive characteristics of this 

species were discussed after the generic description.

Occurrence. Nehonia schesis faunule. Abundant 

(>40 cranidia, pygidia, and free cheeks), USGS colln. 

4443-CO, 6378-CO, 6379-CO, 638(MDO, Nelson Limestone, Neptune Range; 6355-CO, boulder from moraine 

on Mount Spann.

Genus PENSACOLA n. gen.

Type species. Pensacola isolata. n. sp.

Diagnosis. Redlichioid trilobites with prominent 

anteriorly tapered well-defined weakly furrowed glabella that is bluntly rounded anteriorly and reaches to 

nearly straight border furtow. Occipital furrow deep. 

Occipital ring with median node on posterior margin. 

Border convex in sagittal profile; anterior margin moderately rounded. Fixed cheeks upsloping, crescentic. 

Palpaberal lobes, situated about opposite glabellar midlength, form Continuous J-shaped structure with ocular 

ridges. Posterior limbs slender, tapered to sharp points.

Anterior sections of facial sutures extend nearly 

straight forward from palpeforal lobes; posterior sections widely divergent.

Free cheek has well-defined lateral border furrow and 

broad shallow poorly defined posterior border furrow. 

Genal spine short, sharp, broad-based.

Pygidium (?) has transversely elliptical outline and 

is occupied mostly by a 'broad poorly defined axis with 

two ring furrows. Pleural regions small, siibtriangular, 

with deep anterior pleural furrows and shallow second 

furrow. Pygidian margin smooth.

Discussion. This genus most closely resembles 

Asiatic Early Cambrian genera such as Minusinella 

(Repina, 1966, pi. 14, figs. 1-6) and Asiatella (Repina, 

1966, pi. 23, figs. 9-15) by having a J-shaped palpebral 

lobe-ocular ridge combination and a relatively long 

glabella. However, these genera differ from Pensacola 

by having the anterior part of the ocular ridge bifurcated and extended in part in front of the glabella.
EARLY AND MIDDLE CAMBRIAN TRTLOBITES FROM ANTARCTICA D29

The association of the free cheek with the cranidium 

}s based on similarity of ornamentation and comparable 

abundance in several samples. The pygidial association 

is less certain, but its form is consistent with an .assign- 

}nent to the Redlichioidea, and P. isolata is the comjnonest trilobite in the samples yielding pygidia.

Pensacola isolata n. sp. 

Plate 1, figures 11, 12, 15-22

Description. Cranidium moderately convex transversely and longitudinally; outline trapezoidal, anterior 

width twice posterior width; anterior margin moder- 

^itely rounded. Glabella well defined, tapered forward, 

bluntly rounded anteriorly, moderately convex transyersely and longitudinally, extended to inner margin 

<}>f border furrow. Three pairs of glabellar furrows present slightly indenting sides of glabella and continuing 

inward about one-third of glabellar width; posterior 

pair deepest, directed inward and backward from side 

of glabella. Occipital furrow deep, straight, moderately

t

ide, shallowest on axial line. Occipital ring convex, 

aintains nearly constant sagittal and exsagittal width, 

Ipears strong median node adjacent to posterior margin. 

t>asal glabellar width about four-fifths glabellar length 

exclusive of occipital ring. Frontal area composed of 

moderately broad convex border and broad deep border 

jfurrow. Border gently arched in anterior view; sagittal 

length about one-third sagittal g'labellar length.

Fixed cheek upsloping from broad deep axial furrow ; width, exclusive of palpebral lobe about one-half 

basal glabellar width. Palpebral lobe broad, arcuate, 

well defined posteriorly by palpebral furrow, merged 

Imperceptibly forward with poorly defined broad ocular 

ridge that extends posterolaterally from near anterior 

^nd of glabella, situated opposite middle third of 

glabella; width of palpebral lobe about one-half width 

<pf infraocular part of cheek; length between one-half 

^nd two-thirds length of glabella exclusive of occipital 

ring, longest on smaller specimens.

Posterior limb slender, tapered laterally to sharp

int. Posterior border furrow broad, deep; posterior 

3order increases in width distally. Length of posterior 

imb about equal to basal glabellar width.

Anterior section of facial suture directed nearly 

straight forward from palpebral lobe to border furrow, 

 ;hen turned inward across border to intersect anterior 

nargin about two-thirds of distance from anterior 

rani dial corner to axial line. Posterior section of suture 

sigmoid, intersects posterior margin at acute angle.

Free cheek short, broad, lateral margin gently curved, 

glightly deflected outward by short broad-based sharp 

^enal spine. Lateral border well defined by border furrow that is deep at anterior margin but broadens, shallows, and merges backward with broad shallow posterior 

border furrow. Width of border at anterior margin 

about one-half length of anterior section of facial suture 

from border furrow to eye notch. Length of posterior 

margin from intersection of posterior section of facial 

suture to tip of genal spine slightly more than one-half 

length of posterior section of facial suture.

Pygidium, believed to be of this species, transversely 

subovate in outline, length slightly more than one-half 

greatest width. Axis broad, low, poorly defined, occupies 

most of pygidial surface, bears one distinct and one 

barely apparent ring furrow posterior to articulating 

furrow; width slightly less than three-fifths greatest 

pygidial width.

Pleural regions not differentiated into pleural field 

and border, anterior pleural furrow present along inner 

half of anterior margin. A second shallow furrow, 

marked by pits in the positions of the axial and border 

furrows, extends laterally from the first ring furrow. 

Lateral parts of pleural region concave. Posterior margin smooth.

Ornamentation consists of closely-spaced granules on 

all convex parts of the cranidium and free cheek and all 

parts of the pygidimn. The outer part of the cranidial 

border on some specimens and the lateral border of the 

free cheek have well-developed terrace lines. The furrows of the cranidium and free cheek and a narrow band 

along the outer margin of the palpebral lobe are smooth 

or have scattered very fine pits. Surface of the mold has 

scattered pits. On the free cheek, the granular part of 

the ocular platform has an irregular lateral margin near 

the border furrow that seems to be consistently indented 

at two places lateral and posterolateral to the eye notch. 

On the largest specimen, the indentations have a much 

finer granular ornamentation than the other parts of 

the ocular platform. On smaller cheeks, these areas seem 

to be smooth.

Discussion. The possible relationships of this species 

were discussed after the generic diagnosis.

Occurence. Chorbusulina ivttkesi faunule. Common 

(20 cranidia and free cheeks; two pygidia). USGS colln. 

5937-CO, 6308-CO, 6329-CO, 6331-CO, 6352-CO, 

boulders from moraine on Mount Spann.

Genus SCHOPFASPIS n. gen.

Type species. ScJiopfaspis granulosus n. sp.

Diagnosis. Ptychoparioid trilobites with cranidium 

subquadrate, strongly rounded anteriorly. Glabella well 

defined, straight sided, tapered forward, bluntly 

rounded anteriorly. Glabellar furrows shallow to moderately deep. Occipital furrow straight, deepest near 

axial furrows. Occipital ring has small centrally located 

axial node. Frontal area nearly as long as glabella, ex-
D30 CONTKIBUTIONS TO THE GEOLOGY OF ANTAKCTICA

elusive of occipital ring. Subequally divided into gently 

to moderately convex downsloping brim and gently convex subhorizontal border by broad shallow border furrow. A pair of shallow depressions is variably developed 

in the border furrow anterolateral to glabellar corners.

Fixed cheek gently convex, horizontal; width, exclusive of palpebral lobe, about one-half basal glabellar 

width. Palpebral lobes upturned, defined by change in 

slope, situated opposite glabellar midlength; exsagittal 

length slightly more than one-half sagittal glabellar 

length exclusive of occipital ring. Ocular ridges weak.

Posterior limb pointed; transverse length about equal 

to basal glabellar width. Posterior border furrow moderately deep.

Course of anterior section of facial suture slightly 

divergent forward from palpebral lobe; course of posterior section convex outward.

Free cheek narrow. Border convex, slightly wider 

than ocular platform. Lateral and posterior border 

furrows well defined, joined sharply at genal angle. 

Genal spine slender, continues curvature of margin of 

cheek.

Eostral plate wide transversely, with strong lateral 

notches.

Pygidium small, transversely subovate. Axis elevated, 

well defined, about one-third width of pygidium, reaches 

nearly to posterior margin, bluntly rounded posteriorly. 

One ring furrow present posterior to articulating furrow. Pleural regions crossed by several shallow pleural 

and interpleural furrows. Border not clearly defined. 

Posterior margin straight transversely behind axis, 

curved laterally, without spines.

Discussion. The most distinctive features of this 

genus, which differentiate it from other superficially 

similar ptychoparioids, are the presence of a pair of 

shallow depressions in the anterior border furrow of the 

cranidium, the relatively long frontal area and the 

strong curvatures of the anterior border furrow and 

the anterior cranidial margin.

The cranidial proportions (are similar to some Aphelaspidinae, but the presence of a wide (transverse) 

curved rostral plate in Schopfaspis instead of a triangular rostral plate and absence of depressions in the 

axial furrows at the anterolateral corners of the glabella 

typical of the Aphelaspidinae indicates that they are not 

closely related.

The cranidia also show relationships to some species 

of Alokistocare (cf. A. aoris, Rasetti, 1965, pi. 119, figs. 

1-4), but they lack the preglabellar median swelling on 

the brim typical of that genus. However, Schopfaspis 

might be considered as a member of the Alokistocaridae 

when the characteristics of that diverse family are adequately clarified.

Schopfaspis granulosus n. sp. 

Plate 5, figures 8-14

Description. Cranidium subtrapezoidal, anterior 

margin strongly rounded; length about five-sixths 

width between tips of posterior limbs. Glabella well 

defined by shallow axial and preglabellar furrows, 

straight sided, moderately convex transversely, gently 

convex longitudinally, tapered slightly forward, bluntly 

rounded at front. Glabellar furrows short, weakly to 

moderately impressed, posterior pair directed slightly 

backward from axial furrow. Occipital furrow straight, 

deep near axial furrow, shallow across axis. Occipital 

ring gently convex, slightly expanded on axial line, has 

tiny centrally located axial node. Frontal area broad, 

with well-defined brim and border. Sagittal length 

slightly less than sagittal glabellar length exclusive of 

occipital ring. Border furrow broad, shallow, bears pair 

of shallow depressions, variably developed, slightly 

lateral to point midway between axial line and anterolateral cranidial margin; parallel to anterior margin. 

Brim gently to moderately convex, downsloping; sagittal length about equal to sagittal length of evenly convex subhorizontal border.

Fixed cheek gently convex, horizontal; width, exclusive of palpebral lobes about one-half basal glabellar 

width. Palpebral lobe upturned, defined only by change 

in slope, situated opposite glabellar midlength, gently 

curved in plan view; exsagittal length slightly more 

than one-half sagittal glabellar length exclusive of occipital ring. Ocular ridge weakly developed to barely 

apparent, directed slightly posterolaterally from anterolateral corner of glabella.

Posterior limb pointed; transverse length about equal 

to basal glabellar width. Posterior border furrow deep.

Course of anterior section of facial suture slightly 

divergent forward from palpebral lobe to border 

furrow, then curved inward across border to intersect 

anterior margin distal to depressions in border furrow. 

Course of posterior section divergent behind palpebral 

lobe, curved backward to intersect posterior margin 

nearly perpendicularly.

Eostral plate broad transversely, moderately curved 

in plan view, strongly curved in sagittal section; lateral 

margins strongly indented; posterior margin shorter 

than anterior margin. Ventral surface, except for concave zone along anterior margin and strongly upturned 

posterior part, has strong terrace lines.

Hypostome and thoracic segments not known.

Free cheek narrow. Lateral border convex, of uniform 

width, slightly wider than ocular platform, well defined 

by moderately deep lateral border furrow that intersects 

equally deep posterior border furrow sharply at genal 

angle. Genal spine slender, round in cross section, con-
EARLY AND MIDDLE CAMBRIAN TRILOBITE S FROM ANTARCTICA D31

tinues curvature of lateral margin; length from 

posterior sutural margin to tip about 1% times length 

of posterior section of facial suture.

Pygidium small, transversely subovate, anterior and 

posterior margins gently curved, meet laterally at blunt 

point; posterior margin directly behind axis nearly 

straight transversely; margin without spines. Axis 

prominent, barely tapered posteriorly, reaches nearly 

to posterior margin, defined by abrupt change in slope. 

One broad shallow ring furrow present posterior to 

articulating furrow; one additional ring furrow indicated only at sides of axis. Pleural regions gently convex, crossed by two pleural and two interpleural 

furrows, all shallow, about equally spaced, and disappearing before reaching lateral margin. Border not 

clearly differentiated.

External dorsal surfaces of all parts except areas 

above glabellar muscle attachments and palpebral lobes 

are covered with closely spaced low granules.

Discussion. This species cannot be closely matched 

to any described species. Its general affinities and distinctive characteristics were presented in the generic 

discussion.

Occurrence. ScJwpfaspis granulosus faunule. Common (40 cranidia, free cheeks, pygidia, and rostral 

plates), USGS colln. 6313-CO, 6325-CO, 6327-CO, 

6364r-CO, boulders in moraine on Mount Spann.

Genus and species undetermined 1 

Plate 3, figures 10-12

Description. Cranidium subquadrate exclusive of 

posterior limbs, gently convex transversely and longitudinally; width between palpebral lobes about equial 

to length; anterior margin gently rounded. Glabella 

well defined by continuous narrow axial and preglabellar furrows, tapered forward, strongly rounded anteriorly. Occipital furrow slightly sinuous, deep near 

axial furrow, shallow across axis. Occipital ring 

widened slightly towards front on axial line, bears low 

median node. Frontal area downsloping, divided by 

narrow evenly curved border furrow into flat or gently 

convex border and brim; sagittal length about onehalf sagittal length of glabella including occipital ring. 

Border has narrow poorly defined slightly raised anterior rim; sagittal length of border about three-fourths 

sagittal length of brim.

Fixed cheeks moderately wide, gently convex, 

slightly downsloping; width, exclusive of palpebral 

lobes, about three-fifths basal glabellar width. Palpebral lobes small, sharply upturned, defined by change 

in slope, situated opposite or slightly posterior to glabellar midlength, connected to glabella by low straight 

barely apparent ocular ridge; exsagittal length about

one-third or slightly more than one-third of sagittal 

glabellar length exclusive of occipital ring.

Posterior limbs moderately long, bluntly pointed; 

transverse length about equal to basal glabellar width. 

Posterior border furrow deep.

Course of anterior section of facial suture slightly 

divergent forward from palpebral lobe to border furrow, then curved inward across border; intersection 

with anterior margin not apparent. Course of posterior 

section convex, widely divergent behind palpebral lobe, 

nearly perpendicular to posterior margin.

Free cheek narrow, width of border about equal to 

width of ocular platform. Lateral border furrow shallow, merges posteriorly with very shallow posterior 

border furrow. Genal spine flat, margin continuous with 

lateral margin of cheek; length of spine greater than 

length of posterior section of facial suture.

External surfaces of all parts generally smooth; one 

cranidium has faint closely-spaced granules on posterior 

axial part of glabella and occipital ring.

Discussion. This species resembles many nondescript Middle Cambrian ptychoparioid trilobites; without more specimens and a better knowledge of the whole 

trilobite, a meaningful identification is not possible.

Occurrence. Xystridura multilinia faunule. Rare 

(11 cranidia, two free cheeks) USGS colln. 6333-CO, 

boulder from moraine on Mount Spann.

Genus and species undetermined 2

Plate 5, figures 15-17

Discussion. Two incomplete cranidia of a distinctive 

ptychopiarioid trilobite are present in the Schopfapsis 

granulosus faunule. Possibly their discovery elsewhere 

may help to date this faunule more precisely.

The cranidia are characterized by a distinct anteriorly 

tapered truncate unfurrowed glabella that is defined 

only by abrupt changes in slope of the exoskeleton. The 

occipital furrow is very shallow, and the occipital ring 

is relatively broad and gently convex. The brim and 

fixed cheeks are gently convex, relatively broad, and 

downsloping from the glabella. The sagittal length of 

the brim is about half the sagittal length of the glabella 

exclusive of the occipital ring; the width of the fixed 

cheek, including the small, undifferentiated palpebral 

lobes, is slightly more than two-thirds the basal glabellar 

width. The border is concave, and its inner margin is 

extremely poorly defined by a faint narrow inflection of 

the exoskeleton. The deepest part of the concavity of the 

border gives the false impression of being a broad 

shallow border furrow. The sagittal length of the border 

is slightly less than the sagittal length of the brim. The 

anterior sections of the facial sutures are strongly flared 

forward from the palpebral lobes, which are situated
D3,2 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

opposite the middle third of the glabella. The posterior 

section of the facial suture is strongly divergent behind 

the palpebral lobe, but its full course is not known because none of the specimens have the posterior limb preserved. Faint narrow ocular ridges are apparent 011 the 

fixed cheeks after whitening. The cranidia are smooth 

except for a crudely triangular area of granular ornamentation that includes the occipital ring and the posterior part of the glabella (pi. 5, fig. 17).

The unusual ornamentation, flaring frontal area, 

broad brim and fixed cheeks, and generally poor development of all furrows distinguish this species 

from other ptychoparioid trilobites. However, more 

complete specimens are needed to adequately characterize the species for formal naming.

Occurrence. Schopfaspis granulosus faunule. Rare 

(two cranidia), USGS colln. 6325-CO, boulder from 

moraine, Mount Spann.

Genus and species undetermined 3 

Plate 6, figures 15, 19

Discussion. A single collection of badly deformed 

and slightly metamorphosed limestone from a nunatak 

in the Harold Byrd Mountains contains abundant and 

mostly indeterminate trilobite fragments. One distinctive trilobite is recorded here because it may help to 

date the sample. This species is characterized by a 

strongly developed plectrum on the frontal area, an 

anteriorly tapered strongly rounded glabella with two 

pairs of glabellar furrows, a simple occipital ring, 

arcuate palpebral lobes situated about opposite the 

glabellar midlength, and slender moderately long posterior limbs.

The most comparable trilobites are species assigned 

to Mapania, a late Middle Cambrian genus found in 

China and Australia. The specimens are not nearly well 

enough preserved to identify, but they indicate the 

probable presence of rocks of late Middle Cambrian age 

in the Harold Byrd Mountains.

Occurrence. Moderately common (10 cranidia), 

USGS colln. 5466-CO, Harold Byrd Mountains.

Genus and species undetermined 4 

Plate 4, figure 3

Discussion. A single small nepeid cranidium is associated with Trinepea trinodus n. sp. and may be a 

small individual of that species although the differences are much greater than usual between small and 

large holaspids. The small specimen is essentially indistinguishable from Trinepea trinodus posterior to the 

ocular ridges. The ocular ridges have a very shallow 

longitudinal furrow that is typical of most nepeids. The

brim contains only a single median boss, well defined 

by a pair of longitudinal furrows that extend from the 

preglabellar furrow to the border furrow. The border 

is downsloping rather than horizontal as in T. trinodus.

These differences would normally constitute adequate 

grounds for recognizing that the small specimen represents at least a species different from T. trinodus. 

However, until a larger sample of either taxon is obtained, the relationships between the two nepeids will 

be uncertain, and the nomenclature for the small specimen is kept open.

Occurrence. Amphoton oatesi faunule. Rare (one 

cranidium), USGS colln. 4446-CO, Nelson Limestone, 

Neptune range.

COLLECTING LOCALITIES AND FAUNAL LISTS

ARGENTINA RANGE

Mount Spann, 82° S., 41°20' W., close to west base of the 

mountain. Boulders from Holocene moraine. Collected by J. 

M. Schopf, D. L. Schmidt, and W. H. Nelson, January 

1966.

Amtralaspis magnus faunule 

5939-CO, 6311-CO

Australaspis magnus n. sp. 

Grlabrellat pitans n. sp. 

Chorbusulina wilJcesi faunule 

6308-CO

Ohorbusulina wilJcesi n. sp. 

Perisacolct isolata n. sp. 

Bathyuriscellus australis n. sp. 

Redlichia sp. 

5937-CO, 6331-CO

Ohorbusulina wilJcesi n. sp. 

Pensacola isolata n. sp. 

Ohorbusulina subdita faunule 

6312-CO

Ohorbusulina subdita n. sp. 

Bathyuriscellus modestus n. sp. 

6321-CO

Ohorbusulina subdita n. sp. 

Xystridura multiUnia faunule 

6333-CO

Xytridura multiUnia, n. sp. 

Goldfieldia ninguis n. sp. 

Pagetia longispina n. sp. 

Genus and species undetermined 1 

Xystridura glacia faunule 

5938-CO

Xystridura glacia n. sp. 

Schopfaspis granulosus faunule 

6325-CO

Schopfaspis granulosus n. gen., n. sp. 

Pagetidest antarcticus n. sp. 

Liopeishania spannensis n. sp. 

Olenoides sp.

Genus and species undetermined 2 

6313-CO, 6327-CO, 6364-CO

Schopfaspis granulosus n. gen., n. sp. 

Pagetidesl antarcticus n. sp. 

Liopeishania spannensis n. sp.
EARLY AND MIDDLE CAMBRIAN TRILOBITES FROM ANTARCTICA D33

Solenopleura pruina faunule 

6320-CO

Solenopleura pruina n. sp. 

Suludella! davnii n. sp. 

Nelsonia schesis faunule 

6355-CO

Nelsonia schesis n. gen., n. sp. 

Suludellal spinosa n. sp.

NEPTUNE RANGE

1. Outcrop, Nelson Limestone, 83°40' S., 55° 15' W, Collected 

by D. L. Schmidt, January 1964. 

Nelsonia schesis faiunule 

4443-CO

Nelsonia schesis n. gen., n. sp. 

Suludellal spinosa n. sp. 

4445-CO (morainal debris, same area) 

Nelsonia schesis n. gen., n. sp.

2. Outcrops, Nelson Limestone, Mount Dover, 83°50' S.. 55°45' 

W. Collected by D. L. Schmidt, December 1965. 

Nelsonia schesis faunule

6378-CO (basal beds of member 3, Nelson Limestone)

6379-CO (30 feet above base of member 3, Nelson 

Limestone)

6380-CO (31 feet above base of member 3, Nelson 

Limestone)

Nelsonia schesis n. gen., 11. sp. 

Suludellaf spinosa n. sp.

3. Outcrop, Nelson Limestone. 38°37' S., 55°05' W. Collected by 

D. L. Schmidt, January 1964. 

Amphoton oatesi faunule 

4446-CO

Amphoton oatesi n. sp. 

Chondranomocare australis n. sp. 

Kootenia styrax n. sp. 

Trinepea trinodus n. gen., n. sp. 

Peronopsis cf P. fallax (Linnarsson)

HAROLD BYRD MOUNTAINS

Outcrop, isolated nunatak north of Leverett Glacier in the 

Harold Byrd Mountains, 85°40' S., 146° W. Collected by V. H.

Minishew, January 1965. 

5466-CO

Genus and species undetermined 3

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 1916, Cambrian trilobites : Smithsonian Misc. Colln., v. 64, 

no. 5, p. 303-456.

 1925, Cambrian geology and paleontology, part 5, Cambrian and Ozarkian trilobites: Smithsonian Misc. Colln., v.

75, no. 3, p. 59-146. 

Webers, G. F., 1965, An Upper Cambrian archaeocyathid from

Antarctica [abs.] : Geol. Soc. America, Ann. Mtg., Kansas

City, Mo., 1965, Program, p. 180. 

Westergard, A. H., 1946, Agnostidea of the Middle Cambrian of

Sweden: Sveriges Geol. Undersokning, Arsb. 40, no. 1, Ser.

C, no. 477,107 p.

 1953, Non-agnostidean trilobites of the Middle Cambrian 

of Sweden, III: Sveriges Geol. Undersokning, Arsb. 46, no. 

2, Ser. C, no. 526, 42 p.

Whitehouse, F. W., 1936, The Cambrian faunas of northeastern 

Australia ; Part 1, Stratigraphical outline; Part 2, Trilobita 

(Miomera) : Queensland Mus. Mem., v. 11, pt. 1, p. 59-112.

 1939, The Cambrian faunas of northeastern Australia; 

Part 3, The polymerid trilobites: Queensland Mus. Mem., v. 

11, pt. 3, p. 179-242.

Yegorova, L. I., 1961, Trilobity nizhnego kembriya basseyna r. 

Katun' (Gornyy Altay) [Lower Cambrian trilobites from 

the Katun River basin (Altay Mountains) ], in Materialy po 

paleontologii i stratigrafli zapadnoy Sibiri: Sibir. NauchnoIssled. Inst. Geologii, Geoflzki i Mineral'nogo Syr'ya 

(SNIIGGIMS) Trudy, v. 15, p. 215-231.

 1962, O nakhodke novogo vida roda Glabrella v nizhnem 

kembrii [Concerning a discovery of a new species of Glabrella in the Lower Cambrian], in Materialy po paleontologii i stratigrafli zapadnoy Sibiri: Sibir. Nauchno-Issled. 

Inst. Geologii, Geofiziki i Mineral'nogo Syr'ya (SNIIGGIMS) 

Trudy, v. 23, p. 158-159.

Yegorova, L. I., and Savitskiy, V. E., 1968, Trilobity Mayskogo 

Yarusa severa Sibirskoy platformy [Trilobites of the Maya 

Stage, northern Siberian platform] : Paleont. Zhur., no. 1, 

p. 58-70.

 1969, Stratigrafiya i biofatsii kembriya Sibirskoy platformy, Zapadnoe Prianabar'ye [Stratigraphy and biofacies 

of the Cambrian of the Siberian platform, western preAnabar] : Sibir. Nauchno-Issled. Inst. Geologii, Geofiziki i 

Mineral'nogo Syr'ya (SNIIGGIMS) Trudy, v. 43, 408 p.
D36 CONTRIBUTIONS TO THE GEOLOGY OF ANTARCTICA

Yegorova, L. I., and others, 1955, in Khalfin, L. L., ed., Atlas 

rukovodyascbikll form iskopaemykh fauny i flory zapadnoi 

Sibiri [Atlas of leading forms of fossil fauna and flora 

from western Siberia] : Zapadno-Sibir. Geol. Uprav.-Tomsk. 

Politekh. Inst., Moscow, Gosudar. Nauchno-Tekh. Izd. Lit. 

Geol. i Okhrane Nedr, v. 1, 502 p.

 1960, in Khalfin, L. L., ed., Biostratigrafiya Paleozoya 

Sayano-Altayskoy gornoy oblasti; torn 1, Nizhniy [Biostratigraphy of the Paleozoic of the Sayan-Altay mountain

region, Volume 1, Lower Paleozoic] : Sibir. Nauchno-Issled. 

Inst. Geologii, Geofiziki i Mineral'nogo Syr'ya 

(SNIIGGIMS) Trudy, v. 19, 498 p.

Zhuravleva, I. T., 1968, Biogeografiya i geokhronologiya rannego 

kembriya po arkheotsiatam [Biogeography and geochronology of the early Cambrian according to archaeocyathids] : 

Internat. Geol. Cong., 23d, Prague, 1968, Problemy paleontalogii, p. 33-45.
INDEX

[Italic page numbers indicate descriptions and major references]

Page 

Acknowledgments______- __ __ D3

Agnoatus chinensis............................ 10

comes................__..........____ 10

j Lldan Stage, biostratigraphy.. __........... 3

lokistocare aoris.......... ............._... 30

Alokistocaridae__________.._...... 30

Imphoton... ....._.____.__.___._ 9, 17

bensoni................................ ... 18

oatesi.......................... 5, 9, 17, 33; pi. 4

faunule__________._____ 4, 

5, 6, 7,10,18, 19, 22, 25, 32, 33; pis. 3, 4 

serotinum........._____............. 18

spinigerum....................... ....__ 18

steinmanni............................. ... 17

typica.................................... 18

 mphotonella................................. 17

Anomocaridae____._____........... 9,21

.phelaspidinae ............................ 30

Archaeocyatha...___.__.____..._ 1,3 

Asaphiscidae__............................. 9,22

isaphiscus wheeleri........................... 6

Lsiatella... ...__.......................... 28

ustralaspis.................................. 9, 12

magnus........................ 4, 9, 12, 32; pi. 1

faunule................... 4, 13, 27, 32; pi. 1

Jlathyuriscettus............................... 9,19

au$tralU..................... 5, 9, 19, 20,32; pi. 2

firmus........................_._.... 19,20

grandis............... ...._.........__ 20

modestus... .................. 5,9,19,20,32; pi. 2

robustus.................................. 19,20

'athyuriscus....................... ...___ 13

(kootenia)............................. .... 18

dawsoni.......... ...___......__ 18

liattus integer................................. 9

Ibliography................................. 33

IHostratigraphy.____..____.......... 3

jtolaspidetta zone......__.................. 4,6,10

liulaiaspis.................................... 4,12

Calymenecanaliculata-------._...___..... 25

Charaulaspis............................. 15

Chondranomocare....................... 9,21,23

australis........................ 5,9,21,33; pi. 3

bidjensis.................................. 21

exilis..................................... 22

speciosum................................ 22

Ihorbusulina......................... ......... 9, IS

bella....................................... 15,16

subdtta.......................... 5,9,15,32; pi. 2

faunule________... 4,5,16,20,32; pi. 2 

wilkesi.......................... 5,9,16,32; pi. 2

faunule.......... 4,5,16,17,20,29,32; pis. 1,2

'lassiflcation, summary.- _._.... 9

ollecting localities______.._.__.... 32

!onokephalinidae.___.._.----.--._... 9,23

])olichometopidae.-.__-.-.--._...._. 9,17

Dolichometopus deois.......................... 17

Porypygidae._._____....._.__.... 9,18

Elllott Sandstone..____._._.__.__ 7

'aunal lists.

'OMCftOMio...

Page 

Gambacorta Formation.____._........ D6

Genus and species undetermined 1.. ____ 5,

9, SI, 32; pi. 3

Gonus and species undetermined 2..___.. 6,

9, 31, 32; pi. 5

Genus and species undetermined 3.. ___.. 9,

32,33; pi. 6 

Genus and species undetermined i........... 5,

9, S3; pi. 4 

Glabrella..................................... 9,26

mrassina................................. 4,27

pitans.......................... 4,9,07,32; pi. 1

ventrosa.................................. 26,27

GoldfieUia.................................... 9,20

ninguis......................... 5,9,20,32; pi. 3

pacifica... ................................ 20,21

Gondwana. _.___._-----------_....-....- 1

Hoeferia noetlingi.......................------ 16

Jakutidae............................. . 9,19

Jakutus.. _____-----------_------ .- 19

quadriceps................................ 19,20

Judomia zone____-------.-.- ------------ 5,15

Kootenia..................................... 9,18

elongata ornata............................ 19

mendosa.........____--...._ .. 18,19

styrax. ....................... 5,9, 18, 33; pi.4

Lena Stage, biostratigraphy..... __..-....- 3

Liopeishania.......... ___...----.. .. 9,22

lubrica.................................. 6,22,23

spannensis ................... 6,9, 22, 32; pi.4

Mapania..................................... 32

Milesia templetonensis.......-----...---------- 13

Minusinella............-..--.-...-.-.--------- 28

Nelson Limestone, regional correlation .- 7 

stratigraphy..---.-..-------- ---------- 6

Nelsonia...................................... 9,27

schesis................... 6, 9, 25, 27, 28, 33; pi. 6

faunule..----....---- 6, 7,25,28, 33; pi. 6

Neopagetina................................ 11

Neoredlichiidae.................... - 4,9,1*

Nepea......................................-- 25

Nepeidae.. .- -- 6,9.25

Notasaphus--.----. --------------------------- 18

Olenettus brownii...........------------------ 13

Olenoid.es.......-... .- --- 6,9, 19, 32; pi. 5

sp.._ ..-.....-.- 9,19

Oryctocephalidae...----------------------- 5,9,20

Paedeumfas. 

getia.....

bootes....

................... 5,9,10,32;

Pagetides..................-------------------

ampliforns.-.........-.-.-..............--

antarcticus..-.................. 6,9,11,32;

granulosus.

minutus-... 

occidentalis. 

primaeva.... 

puatulosus..

14

9.10

10 

pi. 3

9.11

11

pi. 5 

11

6,11 

11 

11 

11 

11 

11

Page 

Pagetides Continued

rupestris........ .........-__......- Dll

rjonsnitzkii................................ 11

Pagetiidae --_. - - -- 9,10 

Pagetina...................................... 11

Paradozides................................... 13

davidus.............---------------------- 6

forchammeri....--------------------- ...- 4

oelandicus................................ 4

paradoxissimus............................ 4

Paradoxididae. - . 9,13

Patuxent Formation __ - ... ... 6 

Peishania lubrica.............................. . 22

zone......._........ ------ -.-- 23

Pensacola..................................... 9,28

isolata......................... 9,28,29,32; pi. 1

Peronopsis..............................------ 9

ftllax......................... 5,9,10,33; pi. 4

minor.._.____ 10 

Proasaphiscus prims -- 6

Protolenidae...........---..----------------- 9,15

Pseudanomocarina......................------ 21

Psilaspis convexus.---................... 22

Quadragnostidae...-- ----- 9

Redlichia........... ......... .. ... 9,16

chinensis........-.-.-- -------- 17; pi- 1

forresti. ............... . 17

noetlingi.....------.........--.....-...... 17

sp.......... - 5, 9,17, 32; pi. 2

RedUchlidae ------------------------------- 9,16

Resserops...........-------------------------- 12

Schopfaspis.... . - ----- --------- 9,29

gmnulorni -. - 4, 6, 9, 29, 30, 32; pi. 5

faunule- -- 6, 12,19, 23, 31, 32; pis. 4, 5

Shackleton Limestone.. - 7

Solenopleura................------------------ 9,25

canaliculata...........-------------------- 26

holometopa ..................--..------- 26

pruina..........-.. 4, 6, 9, 26, 33; pi. 5

faunule-..----- - 6, 24, 26, 33; pis. 5, 6

zverewi.........--------------------------- 26

Solenopleuridae.. 9,25 

Stratigraphy..-.---------------------------- e

Suludella............ - 9,23,24

damii ................... 6, 9, 23, 33; pi. 6

solita............... . -- --- 23

spinosa................ ..... 6, 9, 24, 33; pi. 6

Sirafa.- 17

Systematic paleontology------------------ 9

Trilobites, first discovery.......... .. 1

Trinepea.- . --------------------- 9,25

trinodus. . 5, 9, 25, 32, 33; pi. 4

TJnassigned trilobites-.-..------------------ ge

Wiens Formation.. 6

Xystridura.-.-......------.--------------- 

glacia.......... 5, 9, IS, 15, 32; pi

faunule.... 4,5,14, 32; pi

multilinia.............. - 5, 9, 14, 32; Pi

faunule- -- 4,5,10,15, 21, 31, 32; pis. 2,

saint-smithi... - 14'

Xystridurinae....----------------------------

D37

PLATES 1-6

Contact photographs of the plates in this report are available, at cost, from U.S. Geological 

Survey Library, Federal Center, Denver, Colorado 80225.
PLATE 1

Early Cambrian

Australaspis ntagnus faunule

FIGURES 1-8. Australaspis magnus n. sp., all figures from USGS colln.

5939-CO except figure 5 from USGS colln. 6311-CO (p. D12).

1. Latex cast of large cranidium, X 1, USNM 169057.

2. Holotype cranidium, X 2, USNM 169058.

3. Cranidium with deep glabellar furrows, X 2, USNM 169059.

4. Cranidium, X 3, USNM 169060.

5. Pygidium, X 4, USNM 169061.

6. Cranidium with shallow glabellar furrows, X 4, USNM 169062.

7. Latex cast of small cranidium, frontal area not fully exposed, X 5, 

USNM 169063.

8. Right free cheek, X 3, USNM 169064. 

9, 10, 13, 14. Glabrella? pitans n. sp. (p. D27).

9, 10, 13. Top, left side, and front views of holotype cranidium, X 3, USNM

169065, USGS colln. 5939-CO. 

14. Close-up of right posterolateral corner of holotype cranidium showing

details of ornamentation, X 10.

Chorbusulina ivilkesi faunule

11, 12, 15-22. Pensacola isolata n. sp.; figures 11, 12, 15, 16, and 18 from USGS colln. 5937- 

CO; figures 17, 21, and 22 from USGS colln. 6331-CO; figures 19 and 20 

from USGS colln. 6308-CO (p. D29).

11. Left free cheek, X 5, USNM 169066.

12. 15. Top and left profile of partly exfoliated cranidium, X 2, USNM 

169067.

16. 18. Top and left profile of pygidium, X 7, USNM 169068.

17. 22. Top and oblique views of small cranidium, X 5, USNM 169069,

19. Holotype cranidium, X 9, USNM 169070.

20. Right free cheek, X 2, USNM 169071.

21. Immature cranidium, X 10, USNM 169072.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D PLATE 1

^ ^^^ HMT^ ^H^^-^w^^^^ ^w«- 

19 20 21 22 

EARLY CAMBRIAN AUSTRALASPIS MAGNUS AND CHORBUSULINA WILKESI FAUNULES
PLATE 2 

Early Cambrian

Chorbusulina wilkesi faunule

FIGURES 1, 2. Chorbusulina wilkesi n. sp. (p. D16).

1. Holotype cranidium, X 6, USNM 169073, USGS colln. 

6329-CO.

2. Small cranidium, X 10, USNM 169074, USGS colln.

6308-CO. 

3-5. Redlichiasp. (p. D17).

3. 4. Fragmentary cranidia, X 4, USNM 169075, 169076,.USGS colln. 

6308-CO.

5. Cranidium of Redlichia "chinensis" from Iran, X 2, illustrated by King 

(1937, pi. 17, fig. 1) for comparison with Antarctic specimens. Photograph of silicone rubber replica 432 in Palmer replica collection, State 

University of New York at Stony Brook.

6-10. Bathyuriscellus australis n. sp., all specimens from USGS colln. 6308-CO 

(p. D19).

6. 7. Top and left side views of holotype cranidium, X 2, USNM 169077.

8. Cranidium, X 2, USNM 169078.

9. Right free cheek, X 2, USNM 169079.

10. Closeup of ornamentation of border of cranidium shown in figure 

8, X 10.

Chorbusulina subdita faunule

11-15. Chorbusulina subdita n. sp., all figures from USGS colln.

6321-CO except figures 11 from USGS colln. 6312-CO (p. D15).

11. Cranidium, X 9, USNM 169080.

12. Right free cheek, X 5, USNM 169081.

13. Holotype cranidium, X 7, USNM 169082.

14. 15. Top and right side views of cranidium, X 5, note contrast in

development of border, USNM 169083. 

16, 17. Bathyuriscellus modestus n. sp. (p. D20).

16. Holotype cranidium, X 1, USNM 169084, USGS colln. 

6312-CO.

17. Closeup of ornamentation of border of holotype cranidium, X 10.

Early Middle Cambrian

Xystridura multiltnia faunule

18-25. Xystridura multilinia n. sp., all specimens from USGS colln. 

6333-CO (p. D14).

18. Cranidium, X 5, USNM 169085.

19. Pygidium, X4, USNM 169086.

20. Cranidium, X 2, USNM 169087.

21. Pygidium, X 4, USNM 169088.

22. Left free cheek, X 2, USNM 169089.

23. Holotype cranidium, X 2, USNM 169090.

24. Pygidium, X 2, USNM 169091.

25. Hypostome, X 3, USNM 169092.
[GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D PLATE 2

10

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19

EARLY CAMBRIAN CHORBUSULINA WILKESI AND C. SUBDITA FAUNULES AND EARLY 

MIDDLE CAMBRIAN XYSTRIDURA MULTILINIA FAUNULE
PLATE 3

Early Middle Cambrian

Xystridura multilinia faunule

FIGURES 1-6. Pagetia longispina n. sp., all specimens from USGS colln. 

6333-CO (p. D10).

1. 6. Top and right oblique views of cranidium, X 15, USNM 169093.

2. Holotype cranidium, X 15, USNM 169094.

3. Pygidium and cranidium, X 12, USNM 169095.

4. 5. Pygidia showing post-axial spine, X 15, USNM 169096, 169097. 

7, 8. Goldfieldia ninguis n. sp., both specimens from USGS colln. 6333-CO 

(p. D20).

7. Holotype cranidium, X 4, USNM 169098.

8. Small cranidium, X 9, USNM 169099.

10-12. Genus and species undetermined 1, all specimens from USGS colln. 6333-CO 

(p. D31).

10. 12. Cranidia, X 6, USNM 169100, 169102.

11. Left free cheek, X 8, USNM 169101.

Xystridura glacia faunule

9, 13-17. Xystridura glacia n. sp., all specimens from USGS colln. 

5938-CO (p. D13).

9. Holotype cranidium, X 1.5, USNM 169103.

13. Latex cast of pygidium, view of doublure showing distribution of 

spines, X 2, USNM 169104.

14. Cranidium, X 1, USNM 169105.

15. 16. Immature cranidia, X 10, USNM 169106, 169107.

17. Latex cast of pygidium, X 2, USNM 169108.

Late Middle Cambrian

Amphoton oatesi faunule

18-24. Chondranomocare australis n. sp., all specimens from USGS colln. 4446-CO 

(p. D21).

18. Small exfoliated cranidium, X 7, USNM 169109.

19. 20. Top and left oblique views of holotype cranidium, X 3, USNM 

169110.

21. Left free cheek, X 5, USNM 169111.

22. Pygidium, X 3, USNM 169112.

23. 24. Right side and top views of partly exfoliated pygidium, X 3.5. 

USNM 169113.
PROFESSIONAL PAPER 456-D PLATE 3

EARLY MIDDLE CAMBRIAN XYSTRIDURA MULTILINIA AND X. GLACIA FAUNULES 

AND LATE MIDDLE CAMBRIAN AMPHOTON OATESI FAUNULE
PLATE 4

Late Middle Cambrian

Am photon oatesi faunule

FIGURES 1, 2. Trinepea trinodus n. gen., n. sp. (p. D25).

Top and left oblique views of holotype cranidium, X 3, USNM 169114,

USGS colln. 4446-CO. 

3. Genus and species undetermined 4 (p. D32).

Crandidium, X 7, USNM 169115, USGS colln. 4446-CO. 

4, 5. Kootenia styrax n. sp., both specimens from USGS colln. 4446-CO (p. D18).

4. Cranidium, X 2.5, USNM 169116.

5. Holotype pygidium, X 3, USNM 169117.

6, 7. Peronopsis cf. P.fallax (Linnarsson), X 10, both specimens from USGS colln. 

4446-CO (p. DIG).

6. Cephalon, USNM 169118.

7. Pygidium, USNM 169119. 

8, 11-13. Amphoton oatesi n. sp., X 4, all specimens from USGS colln. 4446-CO

(P. ) 

8. Left free cheek, USNM 169120.

11, 12. Top and left side views of holotype cranidium, USNM 169121.

13. Pygidium, USNM 169122.

Schopfaspis granulosus faunule

9, 10, 14-22. Liopeishania spannensis n. sp., all specimens from USGS colln. 6325-CO 

(p. D22).

9, 10, 14. Top, left side, and front views of holotype cranidium, X 5, 

USNM 169123.

15. Pygidium, X 3, USNM 169124.

16. Small cranidium, X 11, USNM 169125.

17. 21, 22. Top, front, and left side views of exfoliated cranidium, X 3, 

USNM 169126.

18. Left free cheek, X 5, USNM 169127.

19. Closeup of right anterolateral corner of pygidium shown in figure 15 

showing detail of ornamentation, X 10.

20. Exfoliated pygidia, X 4, USNM 169128.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D PLATE 4

22 

LATE MIDDLE CAMBRIAN AMPHOTON OATESI AND SCHOPFASPIS GRANULOSUS FAUNULES
PLATE 5 

Late Middle Cambrian

Schopfaspis granulosus faunule

FIGURES 1-7. Pagetides? antarcticus n. sp., all specimens from USGS colln. 6325-CO 

(p. Dll).

1-4. Cephalon, lateral profile, thorax, and pygidium of holotype, X 15, 

USNM 169129.

5. Pygidium, X 10, USNM 169130.

6. 7. Right oblique and top views of almost perfect cephalon, X 10,

USNM 169131.

8-14. Schopfaspis granulosus n. sp., all specimens from USGS colln. 6325-CO 

(p. D30).

8. Holotype cranidium, X 6, USNM 169132.

9. Partly exfoliated cranidium, X 5, USNM 169133.

10. Small cranidium, X 9, USNM 169134.

11. 12. Top and left oblique views of cranidium, X 4, USNM 169135.

13. Pygidium, X 5, USNM 169136.

14. Free cheek, X 11, USNM 169137.

15-17. Genus and species undetermined 2, both specimens from USGS colln. 6325- 

CO (p. D31).

15. Latex cast of cranidium, X 5, USTSTM 169138.

16. Cranidium, X 5, USNM 169139.

17. Closeup of unusual ornamentation of occipital area on specimen

shown in figure 16, X 10. 

18. Olenoides sp. (p. D19).

Pygidium, X 5, USNM 169140, USGS colln. 6325-CO.

Solenopleura pruina faunule

19-22. Solenopleura pruina n. sp., all from USGS colln. 6320-CO (p. D26).

19, 20. Top and front views of holotype cranidium, X 3.5, USNM 

169141.

21. Pygidium, X 7, USNM 169142.

22. Right free cheek, X 7, USNM 169143.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 456-D PLATE 5
PLATE 6

Late Middle Cambrian

Solenopleura pruina faunule

FIGURES 1, 2, 5. Suludella? davnii n. sp., all from USGS colln. 6320-CO (p. D23).

1. Holotype cranidium, X 9, USNM 169144.

2. Free cheek, X 6, USNM 169145.

5. Incomplete pygidium, X 5, USNM 169146.

Nelsonia schesis faunule

3, 4, 6-14. Nelsonia schesis n. gen., n. sp.; figures 3, 4 from USGS colln. 6355-CO; 

figures 6-14 from USGS colln. 4443-CO (p. D28). 

3, 4. Cranidia, X 10, USNM 169147, 169148.

6. 10. Right oblique and top views of holotype cranidium, X 10, 

USNM 169149.

7. Cranidium, X 10, USNM 169150.

8. Right free cheek, X 14, USNM 169151.

9. Close-up of visual surface of specimen shown in figure 8, X 40.

11. 14. Top and left side views of pygidium, X 20, USNM 169152.

12. Pygidium, X 10, USNM 169153.

13. Small cranidium, X 10, USNM 169154.

16-18, 20-23. Suludella? spinosa n. sp.; figures 17, 18, and 22 from USGS colln. 4443-CO; 

figures 16, 20, 21, and 23 from USGS colln. 6355-CO (p. D24).

16. 20, 21. Posterior, top, and right side views of holotype pygidium, 

X 5, USNM 169157.

17. Pygidium, X 5, USNM 169158.

18. Incomplete left free cheek, X 4, USNM 169159.

22. Cranidium, X 4, USNM 169160.

23. Cranidium, X 3, USNM 169161.

Faunule unassigned

15, 19. Genus and species undetermined 3, both specimens from USG& colln, 

5466-CO (p. D32).

15. Cranidium, X 4, USNM 169155. 

19. Cranidium, X 2, USNM 169156.
PROFESSIONAL PAPER 456-D PLATE 6

23

LATE MIDDLE CAMBRIAN SOLENOPLEURA PRUINA AND NELSONIA 

SCHESIS FAUNULES AND AN UNASSIGNED FAUNULE