Ostracodes from Lower Devonian Formations 

in Alaska and Yukon Territory 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 

Ostracodes from Lower Devonian Formations 

in Alaska and Yukon Territory 

By JEAN M. BERDAN and M. J. COPELAND 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 

Descriptions and illustrations of an ostracode 

assemblage comprising 7 3 taxa) including 6 new 

genera and 33 new species) of potential value for 

regional correlation in the Arctic province 

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

ROGERS C. B. MORTON, Secretary 

GEOLOGICAL SURVEY 

V. E. McKelvey, Director 

Library of Congress catalog-card No. 73-600212 

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

Washington, D.C. 20402- Price $1.75 (paper cover) 

Stock Number 2401-02407 
~bstract ---------------------------------------- Introd u~ion ________________________ --_---------

~cknowledgments ________ -- _- ____ ------------

Stratigraphy and sedimentation ------------------

~ge and correlation -----------------------------

List of localities ---------------------------------

Systematic paleontology --------------------------

Order Palaeocopida -------------------------- Genus Mesomphalus Ulrich and Bassler, 1913 

Genus Treposella Ulrich and Bassler, 1908 _ 

Genus Beyrichia 1\I'Coy, 1846 ------------

Genus Yulconibeyrichia n. gen -----------

Genus Alaskabolbina n. gen --------------

Genus Ogilvites n. gen ------------------

Genus Abditoloculina KesHng, 195.2 --------

Genus Parabolbina Swartz, 1936 ---------

Genus Hollina Ulrich and Bassler, 1908 ___ _ 

Genus Falsipollex Kesling and McMillan, 

1951 --------------------------------- Genus Hollinella Coryell, 1928 ------------

Genus Abortivelum n. gen ---------------

Genus Adelphobolbina Stover, 1956 --------

Genus Flaccivelum Kesling and Peterson, 

1958 ---------------------------------- Genus Infractivelum n. gen --------------

Genus Chironiptrum Kesling, 1952 --------

Genus Obotritia ~damczak, 1968 ----------

Genus Kirkbyella Coryell and Booth, 1933 _ 

Genus Hanaites Pokorny, 1950 ------------

Genus Subarc,tichites n. gen --------------

Genus Libumella Rozhdestvenskaya, 1959 __ 

Genus Neoaparchites Boucek, 1936 ________ _ 

Genus Aparchites Jones, 1889 ------------

Genus Eukloedenella Ulrich and Bassler, 

1923 --------------------------------- Genus Poloniella Giirich, 1896 ------------

CONTENTS 

Page 

1 

1 

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2 

4 

8 

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9 

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Systematic paleontology-Continued 

Order Podocopida ----------------------------

Genus Bairdia M'Coy, 1844 ---------------

Genus Rectobairdia Sohn, 1961 -----------

Genus Bairdiolites Groneis and Gale, 1939 __ 

Genus Newsomites Morris and Hill, 1952 __ 

Genus Acanthoscapha Ulrich and Hassler, 

1923 --------------------------------- Genus Shidelerites Morris and Hill, 1951 __ _ 

Genus Beecherella Ulrich, 1891 -----------

Genus Camdenidea Swain, 1953 -----------

Genus Tricornina Boucek, 1936 -----------

Genus Bicornina Jordan, 1964 ------------

Genus Berounella Boucek, 1936 ------------

Genus Bairdiocypris Kegel, 1932 ---------

Genus Kuresaaria ~d!amczak, 1967 -------

Genus Bairdiohealdites McGill, 1968 ------

Genus Praepilatina Polenova, 1970 --------

Genus Barychilina Ulrich, 1891 -----------

Genus Trypetera Kesling, 1954 ------------

Genus Voronina Polenova, 1952 -----------

Genus Cavellina Coryell, 1928 ------------

Genus Tubulibairdia Swartz, 1936 ---------

Pachydomellid indet. 1 -------------------

Pachydomellid indet. 2 -------------------

Genus Eriella Stewart and Hendrix, 1945 --

Genus Neocraterellina Krandijevsky, 1968 __ 

Genus Microcheilinella Geis, 1933 ----------

Ostracode indet. 1 -----------------------

Ostracode indet. 2 -----------------------

Ostracode indet. 3 -----------------------

References cited ---------------------------------

Index -------------------------------------------

ILLUSTRATIONS 

[Plates follow index] 

PLATE 1. Mesomphalus? and Treposella. 

2. Beyrichia (Beyrichia). 

3. Beyrichia (Scabribeyrichia). 

4. Yukonibeyrichia. 

5. Alaskabolbina and Alaskabolbina?. 

6. Ogilvit~s, Abditoloculina, Abortivelum, Adelphobolbina, and Hollina. 

7. Hollinella, Adelphobolbina, and Falsipollex?. 

8. Obotritia?, Chironiptrum, Flaccivelum, Parabolbina, and lnfractivelum. 

9. Kirkbyella, Hanaites, and Subarctichites. 

10. Libumella, Neoaparchites?, and "Aparchites." 

III 

Page 

30 

30 

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36 

36 

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37 

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40 

41 

45 
IV CONTENTS 

PLATE 11. Bairdia, Bairdiolites?, Beecherella?, Acanthoscapha, Rectobairdia, Shidelerites, Eukloedenella, and Poloniella (Framella). 

12. Tricornina, Bicornina, Berounella, BairdiofJJypris?, Bairdiocypris, and Kuresarria. 

13. Camdenidea, Praepilatina, Bairdiohealdites?, and Voronina. 

14 Eriella?, Microcheilinella?, Neocraterellina?, Cavellina (lnvisibila) ?, 

Newsomites?, Barychilina?, Trypetera?, Tubulibairdia, and ostracodes 

indet. 

Page 

FIGURE 1. Index map showing locations of sections from which ostracodes were 

collected in Alaska and Yukon Territory ------------------- 2 

2. Diagrammatic sections of the McCann Hill Chert and Michelle and 

Prongs Creek Formations showing positions of ostracode collections ----------------------------------------------------- 4 

3-7. Scatter diagrams showing length versus height of: 

3. Beyrichia (Beyrichia) brabbi -------------------------- 11 

4. Beyrichia (Scabribeyrichia) churkini -------------------- 12 

5. Yukonibeyrichia yukonensis ---------------------------- 13 

6. Chironiptrum limitaris --------------------------------- 23 

7. Hanaites brevis --------------------------------------- 26 

TABLE 

TABLE 1. Ostracode taxa described in this paper and the formations and collections in which they occur --------------------------------J 6 
OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN 

ALASKA AND YUKON TERRITORY 

By JEAN M. BERDAN and l\1. J. CoPELAND1 

ABSTRACT 

Residues of samples, dissolved in acetic and formis acid 

from the limestone and shale member of the McCann Hill 

Chert of eastern Alaska and the Michelle and Prongs Creek 

Formations of Yukon Territory have revealed the presence 

of a varied, silicified ostracode fauna. This fauna may serve 

as a basis for correlating strata from the Alaska-Yukon 

international boundary near lat 65° N. northeastward for 

more than 200 miles. 

Of the more than 40 genera present, hollinaceans and 

beyrichiaceans are the most distinctive. The hollinaceans 

find their closest affinity with genera from lower Middle 

Devonian (Eifelian) beds from the midcontinent region of 

North America, and the beyrichiaceans with genera from 

Lower Devonian and Silurian strata of Ap,palachian North 

America and of Europe. Conodonts and dacryoconarid 

tentaculites indicate that the age of the collections from 

which the ostracodes were obtained is late Early Devonian 

(Emsian), but the ostracode assemblage reported here does 

not resemble any described Emsian fauna. 

These ostracodes are considered to represent a provincial 

assemblage with some Silurian survivors and some precursors of Middle Devonian forms which subsequently migrated to Eurasia and central North America. In all, 73 

taxa, including 6 new genera and 33 new species, are described and illus·trated. 

INTRODUCTION 

The McCann Hill Chert of Alaska and the Michelle 

and Prongs Creek Formations of Yukon Territory, 

Canada, contain a large fauna of invertebrate fossils which includes a varied and abundant assemblage of ostracodes. Some of the silicified ostracodes 

from the McCann Hill Chert have been listed and 

illustrated by Berdan (in Churkin and Brabb, 1967), 

and silicified ostracodes from the Michelle and 

Prongs Creek Formations have been listed by Copeland (in Ludvigsen, 1970). Copeland (in Norris, 

1967a, sections 16, 17, and 19) also reported several 

nonsilicified specimens from the Michelle Formation 

in the vicinity of Hart and Blackstone Rivers, Yukon Territory. The present paper is the first comprehensive description of the silicified ostracode 

assemblage from these formations. 

1 Geological Survey of Canada, Ottawa, Ontario, Canada. 

The first of the silicified ostracode faunules was 

found in USGS collection 6492-SD, from the basal 

limestone and shale member of the McCann Hill 

Chert, one half mile west of Hillard Peak, Alaska, 

and 3.4 miles N. 41 o W. of International Boundary Commission monument 105, (64°57'03" N., 

141 °04'05" W.). From this collection, Berdan (in 

Churkin and Brabb, 1967, table 1, pl. 4) reported 20 

species belonging to 18 genera, and illustrated 14 of 

these species. Later, similar silicified ostracodes 

were obtained by Ludvigsen (1970) from five sections (I-V) in Yukon Territory, from the Michelle 

Formation of Blackstone and Hart Rivers (about 

65°41' N., 137°00' W.) and the Prongs Creek Formation of Solo Creek (65°51.4' N., 134°15.5' W.). Copeland (in Ludvigsen, 1970, p. 426) listed 10 species 

of 9 genera from each of the Michelle and Prongs 

Creek Formations. In all, the present authors previously recognized 19 known and 2 unnamed ostracode genera. Further study of the original and additional collections has resulted in this report, in 

which 73 ostracode taxa are described and illustrated. Of these, 6 genera and 33 species are new. 

The ostracode occurrences are scattered from near 

the Alaska-Yukon international boundary at lat 65° 

N. for more than 200 miles northeastward to eastern 

Yukon Territory (fig. 1). Although many of the 

species are known as yet from only one collection or 

locality, some of them are widely distributed, and 

the similarity of the ostracodes on the generic level 

suggests that they are approximately the same age. 

The silicified specimens described here may serve as 

a basis for widespread correlation within the Yukon 

Shelf of Alaska and Yukon Territory and, in Yukon, 

across the trough of the Richardson Mountains. 

Some of the taxa are similar to described species 

from the Devonian of Asiatic and European parts 

of the U.S.S.R. and may indicate routes of migration 

during the Devonian. 

ACKNOWLEDGMENTS 

We are grateful toR. Ludvigsen, Calgary, Alberta, 

for permission to describe the ostracode faunules 

1 
2 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

St Matthew 1\ 

CJ 

ARCTIC 

CHUKCHI 

SEA 

Barrow 

PACIFIC 

OCEAN 130° 

GULF OF ALASKA 56" 

0 100 200 MILES 

OCEAN 

FIGURE 1.-Locations of measured sections from which ostracodes have been collected in Alaska and Yukon Territory. 1, 

Type section of McCann Hill Chert described by Churkin and Brabb (1965); 2, sections II and III of the Michelle Formation described by Ludvigsen (1970); 3, section IV of the Michelle Formation described by Ludvigsen (1970); 4, 

s·ection I of the Michelle Formation described by Ludvigsen (1970); 5, s·ection V of the Prongs Greek Formation described by Ludvigsen (1972). 

obtained by him in Yukon Territory during the summer of 1968 while he was employed by Gulf Oil, 

Canada, Limited. Appreciation is expressed to R. 

Ludvigsen, to A. C. Lenz, University of Western 

Ontario, and to A. W. Norris, Geological Survey of 

Canada, for revision and comments on the Canadian 

stratigraphic part of the paper, and to Michael 

Churkin, Jr., E. E. Brabb, and J. T. Dutro, Jr., all 

of the U.S. Geological Survey, for review of the 

Alaskan stratigraphic part of the paper. I. G. Sohn, 

U.S. Geological Survey, and Thomas E. Bolton, Geological Survey of Canada, critically reviewed the 

manuscript. 

STRATIGRAPHY AND SEDIMENTATION 

Throughout the area under discussion, strata of 

the McCann Hill Chert and Michelle and Prongs 

Creek Formations overlie graptolitic shale of the 

Road River Formation containing Monograptus 

yukonensis Jackson and Lenz, 1963, which according 

to Jaeger (1970, p. 174-175) is Early Devonian in 

age (Siegenian? to possibly late Emsian). In the 

west, the contact of the McCann Hill Chert with the 

Road River Formation appears to be accordant in 

the section from which the ostracodes were obtained, 

although there is possible evidence of a stratigraphic 

break between the formations-a single cobble of 

graptolitic shale in the basal McCann Hill Chert 

(Churkin and Brabb, 1965, p. 181; 1967, p. 231). 

According to Ludvigsen (1970, p. 412), in the Hart 

River-Blackstone River area, the Michelle Formation has a gradational contact with the Road River 

Formation, although Norris (1967b, p. 758) suggested that the contact may be unconformable. The 
STRATIGRAPHY AND SEDIMENTATION 8 

contact of the Prongs Creek Formation with the 

Road River in the Solo Creek area has not been described in detail, but in the area that includes Solo 

Creek, Norris (1967b, p. 770) stated that the contact 

is within shales and was tentatively drawn above 

the highest occurrence of monograptids, although 

farther north at Trail River the contact is an erosional unconformity. Ludvigsen (1972, p. 302) also 

drew the contact of the Road River and Prongs 

Creek immediately above the highest occurrence of 

graptolites. 

The McCann Hill Chert in its type section, from 

which the ostracodes described in this report were 

obtained, is abruptly overlain by the lowermost sandstone beds of the Nation River Formation (Upper 

Devonian). According to Churkin and Brabb (1965, 

p. 181; 1967, p. 232-233) there is no evidence for a 

stratigraphic break at the contact, and the upper 

part of the McCann Hill contains spores similar to 

those in the overlying Nation River; consequently, 

the formations are probably conformable. The Michelle Formation is overlain by the Ogilvie Formation in the Hart River-Blackstone River area; the 

contact is sharp and may represent a disconformity 

(Norris, 1967b, p. 770; Ludvigsen, 1970, p. 412; 

1972, fig. 2). The Ogilvie is considered to be Early 

and Middle Devonian in age by Ludvigsen (1972, 

fig. 2). The section from which ostracodes were obtained in the Prongs Creek Formation is incomplete, 

and the contact of the Prongs Creek with the overlying formation is unknown. Norris (1967b, fig. 4) 

postulated a change of facies in the area in which 

this section occurs. 

The regional relationships and correlation of the 

McCann Hill Chert and the Michelle and Prongs 

Creek Formations have been discussed by Churkin 

and Brabb (1967), Lenz (1967, 1972), Norris 

(1967b), apd Ludvigsen (1972). Details about the 

type locality of the McCann Hill Chert and the associated faunas are given by Churkin and Brabb 

(1965, p. 184, figs. 2, 4) ; the locality is also shown 

on a geologic map of the Eagle (D-1) quadrangle, 

Alaska (Brabb and Churkin, 1965). Details of many 

sections of the Prongs Creek and Michelle Formations in Yukon Territory have been described by 

Norris ( 1967 a, 1968) . 

The general character of the lithologies of the 

McCann Hill Chert and the Michelle and Prongs 

Creek Formations in the sections from which ostracodes are described in this report and the stratigraphic position of the collections within the sections are shown in figure 2. The McCann Hill Chert 

is a 200- to 1,000-foot-thick sequence of thinly 

bedded, laminated light-gray to black chert alternating with siliceous shale and shale, and has a 250-footthick limestone and shale member at its base (Churkin and Brabb, 1965, p. 180, 181). The basal limestone and shale member, from which the ostracodes 

were obtained, consists of lenticular beds of darkgray bioclastic limestone interbedded with darkgray to grayish-black calcareous shale, siltstone, 

chert grit, and laminated limestone ( Churkin and 

Brabb, 1965, p. 180). According to Ludvigsen (1970, 

p. 410, 412), in the three sections from which collections were made, the Michelle Formation "consists of moderately resistant, grey and buff-orange 

weathering, platy to thick-bedded argillaceous limestone with minor non-argillaceous limestone and calcareous shale." The argillaceous limestone is dark 

gray to black, micrograined to very fine grained, and 

some beds are fetid. The Prongs Creek Formation 

on Solo Creek is "a drab sequence of unfossiliferous, 

black, calcareous shales with interspersed lenses and 

beds of breccia composed of limestone, dolomite, or 

completely replaced by silica" (Ludvigsen, 1972, p. 

302). These fossiliferous breccias are considered by 

Norris (1968, p. 23) and Ludvigsen (1972, p. 302) 

to have been deposited by turbidity currents. 

Hand specimens of the McCann Hill Chert, from 

its type section, that have yielded silicified ostracodes (USGS collns. 6492-SD, 7032-SD, and 7033-

SD) are gray bituminous bioclastic limestone in 

which many of the megafossils are broken, suggesting a high-energy environment. Two samples from 

the McCann Hill (USGS collns. 7037-SD and 7038-

SD), which were collected from outcrops 300 feet 

east of the type section and are therefore not shown 

on figure 2, are also bioclastic but are more siliceous 

and include a considerable amount of chert. These 

samples were described as being from thin beds of 

limestone conglomerate in a shale sequence (Brabb, 

written commun., 1963). In one of these collections, 

USGS collection 7037-SD, the ostracodes are in general smaller; many juvenile specimens occur, and 

also many species that have not been found in the 

other collections. USGS collection 7038-SD, which is 

only 5 feet higher than USGS collection 7037-SD, 

contains virtually the same assemblage as in USGS 

collections 6492-SD, 7032-SD, and 7033-SD from 

about 10 feet of the type section. The differences between the ostracode assemblage in USGS collection 

7037-SD and that in the other collections is believed 

to be due to local facies control rather than different 

stratigraphic position. 

Hand specimens of Ludvigsen's collections from 

the Michelle and Prongs Creek Formations were not 

available for study. 
4 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

ALASKA 300 FEET 

McCann Hill Chert 

200 

100 

0 

II 

116 MILES -

'I} 

-

><1 

- -

I J 1\ 

-L-~_r\ 

-

YUKON 

Michelle 

12 MILES 

11-14 

11-13 

IJ-11 

11-10 

III 

TERRITORY 

Formation 

IV 13 MILES 

IV-3 

I 

-

.:?<I 

'\ -

:?<:1 

-

II 

-

- -

Prongs Creek 

Formation 

v 

@1 I I 

EXPLANATION 

-

Conglomerate 

~ 

~ 

Graywacke Siliceous 

~ 

~ 

~ ~ 

shale 

Chert, 

bedded 

Calcareous 

shale 

Shaly 

limestone 

Limestone Limestone and Covered 

dolostone breccia interval 

FIGURE 2.-Diagrammatic sections showing generalized lithology of the McCann Hill Chert, Michelle Formation, and 

Prongs Creek Formation and positions of ostracode collections. Sections are arbitrarily arranged with reference to 

the top of the underlying Road River Formation, as determined by Churkin and Brabb in Alaska and Ludvigsen in 

Yukon Territory; overlying formations not shown. Adapted from Churkin and Brabb (1965, fig. 4, section 5), Fahrae.us 

(1971, fig. 2), and Ludvigsen (1972, fig. 5). 

AGE AND CORRELATION 

The McCann Hill Chert and Michelle and Prongs 

Creek Formations contain a wide and varied fauna 

of invertebrates and vertebrates. Churkin and Brabb 

(1967) listed and illustrated some of the fossils from 

the McCann Hill Chert, and Churkin and Carter 

(1970) described the tentaculite fauna. In addition, 

Ormiston (1969) described a trilobite from the 

lower limestone and shale member of the McCann 

Hill Chert (USGS colin. 6492-SD). Ludvigsen 

( 1970) discussed the fauna and illustrated brachiopods and tentaculites from the Michelle Formation 

and later (Ludvigsen, 1972) described the dacryoconarid tentaculites from the Michelle and Prongs 

Creek Formations. Stearn and Mehrota ( 1970) described the stromatoporoids of the Michelle and 

Prongs Creek Formations, Ormiston (1971) described the trilobites from the Michelle Formation, 

and Fahraeus (1971) described the conodonts from 

the Michelle and Prongs Creek Formations. The ages 

of the three formations have been assigned largely 

on the basis of the conodonts and the dacryoconarid 

tentaculites. 

The McCann Hill Chert fauna (USGS colin. 6492-

SD) of ostracodes, bryozoans, trilobites, brachiopods, 

pelecypods, conodonts, and tentaculitids listed by 

Churkin and Brabb (1967, p. 232-233) was considered by them to be Emsian (late Early Devonian) 

in age and to correlate with the upper part of the 

Salmontrout Limestone of the Porcupine-Salmontrout Rivers area, Alaska. A probable late Emsian 

Age for USGS collection 6492-SD is suggested by 

the occurrence of the tentaculitid N owakia barrandei Boucek and Prantl, reported from this collection 

by Churkin and Carter (1970, p. 63), which, accord-
AGE AND CORRELATION 5 

ing to Boueek (1967, p. 1278), is typical of "uppermost Zlichovian or even of very basal Eifelian" beds 

in Bohemia. Huddle (in Ormiston, 1969, p. 1210-

1211) reported the late Emsian conodont Polygnathus foveolatus Philip and Jackson from the same 

collection, and Klapper and others (1971, fig. 1) 

showed the basal McCann Hill as late Emsian and 

correlated it with the Blue Fiord Formation of 

Devon Island in the Canadian Arctic Archipelago 

and the upper Eurekaspirifer pinyonensis Zone of 

Nevada. Ormiston (1969, p. 1211-1212) considered 

the trilobite Koneprusia sp. from USGS collection 

6492-SD to be most like K. subterarmata (Barrande) from the upper Emsian of the Harz region 

in Germany. In addition, USGS collection 6492-SD 

contains the two-holed crinoid ossicle Gasterocoma? 

bicaula Johnson and Lane, which Johnson and Lane 

(1969, p. 70) considered late Emsian to Eifelian in 

age. Corals from the limestone and shale member of 

the McCann Hill which were considered Middle Devonian by Oliver (in Churkin and Brabb, 1965, p. 

181) do not come from the same localities as the 

ostracodes described here. 

The Michelle Formation fauna of brachiopods, 

tentaculites, nautiloids, trilobites, conodonts, and 

ostracodes was discussed and the brachiopods and 

tentaculites were illustrated by Ludvigsen (1970), 

who evaluated it as follows: (1) brachiopods indicate at least partial contemporaneity with those of 

the Eurekaspirifer pinyonensis Zone (Emsian) of 

Nevada; (2) the tentaculite fauna is tentatively correlated with the Guerichina strangulata Zone of late 

Praguian (early Emsian) Age in Bohemia; (3) trilobites indicate an undifferentiated Emsian Age, 

with no forms indicative of the late Emsian; ( 4) 

conodonts indicate correlation with the Polygnathus 

lenzi fauna of early Emsian Age. This assessment 

indicates that the age of the Michelle Formation is 

Emsian and possibly early Emsian. Later, Fahraeus 

(1971) described and illustrated the conodonts from 

Ludvigsen's collections from both the Michelle and 

Prongs Creek Formations. Fahraeus (1971, p. 670-

671) concluded that the Michelle collections were 

late early Emsian (late Praguian) in age, because 

of the presence of Polygnathus dehiscens Philip and 

Jackson, which he considered a senior synonym of 

P. lenzi Klapper. He noted that the highest collection (V-5, fig. 2) from the Prongs Creek Formation 

on Solo Creek also contained P. dehiscens, implying 

a correlation between this part of the Prongs Creek 

and the Michelle. Ludvigsen (1972) described the 

dacryoconarid tentaculites from the Michelle and 

Prongs Creek Formations and concluded that they 

indicated an early Emsian Age, he cautioned (Ludvigsen, 1972, p. 303), however, that a straightforward correlation with the Bohemian succession cannot be made because of the overlapping teilzones in 

the Michelle of the Praguian tentaculite Turkestanella acuaria (Richter) and the Zlichovian Nowakia 

parabarrandei. 

An undifferentiated Emsian Age was suggested by 

House (in House and Pedder, 1963, p. 508) for the 

goniatite Teicherticeras lenzi from beds later included by Norris (1967b, p. 759) in the Michelle 

Formation. The two-holed crinoid ossicle Gasterocoma? bicaula of late Emsian to Eifelian Age, which 

occurs in the limestone and shale member of the McCann Hill Chert, has also been reported from the 

Prongs Creek Formation (Norris, 1967b, p. 770) and 

the Michelle Formation (Ludvigsen, 1970, p. 427) 

but also occurs abundantly in the overlying Ogilvie 

Formation (Norris, 1967b, p. 773). 

In summary, previously described fossils suggest 

that the limestone and shale member of the McCann 

Hill Chert, the Michelle Formation, and the Prongs 

Creek Formation are all Emsian in age. Conodonts 

and dacryoconarid tentaculites indicate that Churkin and Brabb's collections from the limestone and 

shale member of the McCann Hill are late Emsian 

and that Ludvigsen's collections from the Michelle 

and Prongs Creek are early Emsian. 

The silicified ostracodes obtained by Churkin and 

Brabb are from five collections from the limestone 

and shale member in the type area of the McCann 

Hill Chert; two collections from the measured section are about 10 feet apart stratigraphically and 

about 140 to 150 feet above the base of the formation. Those obtained by Ludvigsen are from (1) 

six collections from the Michelle Formation, four 

of which, from one locality on the east side of the 

Blackstone River (Ludvigsen collections II-10 to 

14, fig. 2), span a stratigraphic thickness of about 

175 feet, starting about 300 feet above the base of 

the formation; and (2) three collections from the 

Prongs Creek Formation on Solo Creek which span 

a stratigraphic interval of about 140 feet, starting 

about 150 feet above the base of the formation. The 

ostracode taxa described in this paper and the collections in which they occur are listed in table 1. 

Of the 73 ostracode taxa listed in table 1, 51 have 

been found in the collections from the McCann Hill 

Chert, 28 in the collections from the Prongs Creek 

Formation, and 17 in collections from the Michelle 

Formation. Of the total number, 18 are represented 

by only 1 specimen and are therefore not significant 

for correlation between the formations; 6 of these 
6 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

TABLE !.-Ostracode taxa described in this paper and the for-mations and collections in which they occur 

Ostracodes 

J.feso-mphalus? sp --------------------------------------- Treposella borealis n. sp --------------------------------- Treposella sp. cf. T. lyoni (Ulrich) ----------------------- Beyrichia (Beyrichia) brabbi n. sp ----------------------- (Scabribeyrichia) churkini n. sp ---------------------

Yukonibeyrichia yukonensis n. sp ------------------------

solo n. sp ------------------------------------------ Alaskabolbina unilineata n. sp --------------------------

bilineata n. sp -------------------------------------- nodilineata n. sp ------------------------------------

sp ------------------------------------------------- ? sp ----------------------------------------------- Ogilvites bicornis n. sp --------------------------------- Abditoloculina clausa n. sp ------------------------------

clausa? --------------------------------------------

~~~~~~b~~a Falsipollex? ~~--=========~=============================== -multispinosus n. sp -------------------------

Hollinella ludvigseni n. sp -------------------------------

paucituberculata n. sp ------------------------------- Abortivelum truncatum, n. sp ----------------------------

Adelphobolbina aliquanta n. sp --------------------------

prongsens~ n. sp ---------------------------------- sp. cf. A. medialis Stover -----------------------------

Flaccivelum sp ----------------------------------------- lnfractivelum acuminatum n. sp -------------------------

spiculosum n. sp ------------------------------------ Chiro?ti'l!tru.m reticularis n. sp --------------------------

bm1tar1s n. sp ------------------------------------- Obotritia? sp ------------------------------------------- Kirkbyella (Kirkbyella) sp ----------------------------- Hanaites linearis n. sp -----------------------------------

brevis n. sp ---------------------------------------- spinosus n. sp -------------------------------------- Subarctichites serratulus n. sp --------------------------- Libumella sp. cf. L. discoides Rozhdestvenskaya ----------- sp. cf. L. circulata Rozhdestvenskaya ----------------- Neoaparchites? sp. aff. N.? insericus (Rozhdestvenskaya) 

"Aparchites" sp. aff. "A." auriculiferus Rozhdestvenskaya __ 

Eukloedenella recta n. sp ---------------------------------

soloensis n. sp ------------------------------------- Poloniella (Framella) sp. aff. P. (F.) scheii Weyant _______ _ 

Bairdia sp. cf. B. leguminoides Ulrich ---------------------

dejecta n. sp ---------------------------------------

Rectobairdia sp ---------------------------------------- Bairdiolites? sohni n. sp --------------------------------

Newsomites? sp ---------------------------------------- Acanthoscapha sp ----------------------- -------------- Shidelerites yukonensis n. sp -----------------------------

Beecherella? sp -----------------------------------------

Camdenidea sp ----------------------------------------- "Tr:icor'Y!ina" caurina n. sp ------------------------------

Tr1cornzna sp ------------------------------------------ B" . tcorntna sp ------------------------------------------- Berounella sp. aff. B. minuta Blumenstengel --------------- Ba~rd~ocypr~s? sp. cf. B.? cordiformis Rozhdestvenskaya ___ _ 

Ba1rdwcypr1s sp ---------------------------------------- Kuresaaria blackstonensis n. sp -------------------------

Bairdiohealdites? scapulatus n. sp ------------------------ Praepilatina sp. aff. P. praepilata sibirica Polenova ---------

Barychilina? sp _ ---------------------------------------

Trypetera? sp ------------------------------------------

McCann Hill 

X X X 

X X X 

X X X 

X X X 

X 

X X X 

X 

X X 

X 

X 

X X X 

X X 

X X 

X X X 

X X X 

X X X 

X X X 

X X X 

X 

X X 

X 

X 

X 

X X 

X 

X X 

X X X 

X X X 

X 

X 

X 

X 

X X 

X 

X X 

X X 

X 

X 

X X 

X X 

X 

X 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X X 

X 

X 

X X 

X 

X X 

Collections 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Michelle 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Prongs Creek 

X 

X 

X X 

X X 

X X X 

X X 

X 

X 

X 

X 

X 

X X 

X X 

X 

X X X 

X X 

X X X 

X X X 

X 

X X 

X 

X 

X 

X X X 

X 
AGE AND CORRELATION 7 

TABLE !.-Ostracode taxa described in this paper and the formations and collec.tions in which they occur-Continued 

Ostracodes 

Voronina sp. cf. V. inventa Rozhdestvenskaya --------------

Cavellina (lnvisibila)? sp ------------------------------- Tubulibairdia sp ---------------------------------------- Pachydomellid indet. 1 ---------------------------------- Pachydomellid indet. 2 ----------------------------------

Eriella? sp --------------------------------------------- Neocraterellina? crescentifera n. sp ---------------------- Microcheilinella? sp __________________ ----______________ _ 

Ostracode indet. 1 -------------------------------------- Ostracode indet. 2 ---------------------------------------

Ostracode indet. 3 --------------------------------------

rare specimens occur in the McCann Hill Chert, 6 in 

the Michelle Formation, and 6 in the Prongs Creek 

Formation. Three of the single specimens from the 

Michelle Formation are from Ludvigsen collection 

1-3, which is shown by Ludvigsen (1972, fig. 3) as 

being more than 200 feet below the other ostracodebearing collections from the Michelle. Of the 22 significant taxa in the Prongs Creek, 13 also occur in 

the collections from the McCann Hill Chert, and of 

the 11 significant taxa in the Michelle, 8 also occur 

in the McCann Hill collections. The Michelle and 

Prongs Creek collections have five taxa in common. 

These figures include three species of beyrichiids 

which occur in all three formations. The ostracodes, 

as well as the other groups of fossils, therefore, suggest that at least part of the Michelle and Prongs 

Creek Formations and the limestone and shale member of the McCann Hill Chert are approximately the 

same age. 

For purposes of intercontinental correlation the 

ostracodes are of little assistance in confirming the 

age of the Michelle and Prongs Creek Formations 

and of the limestone and shale member of the McCann Hill Chert as determined by other groups of 

fossils. This is partly because most of the species are 

new, but also because at least seven of the genera 

have not hitherto been reported from beds older than 

Middle Devonian (Eifelian), and six have not been 

reported from beds younger than middle Early Devonian (Siegenian). On a generic level, the most 

distinctive groups are the hollinaceans and the 

beyrichiaceans. The hollinacean genera A bditoloculina, Adelphobolbina, Falsipollex, Flaccivelum, H ollina, and H ollinella and the beyrichiacean Treposella 

would under other circumstances appear indicative 

McCann Hill 

X X 

X 

X X X X 

X X X X 

X 

X 

X X X X 

X 1--

0 

...... 

,..!., 

...... 

Collections 

...... 

...... 

~ 

Michelle Prongs Creek 

X 

X 

X 

X 

X 

of early Middle Devonian (Eifelian) age. All seven 

genera listed above occur with Eifelian conodonts 

(Huddle, oral commun., 1972) in collections from 

the Paraspirifer acurninatus Zone of the Jeffersonville Limestone at the Falls of the Ohio between 

Jeffersonville, Ind., and Louisville, Ky.; the hollinids 

have been described by Kesling and Peterson ( 1958) . 

None of them has been found in upper Lower Devonian (Emsian) formations in eastern North 

America such as the Camden Chert (Bassler, 1941 ; 

Swain, 1953) or the Schoharie Formation (Berdan, 

1971), nor have they been reported from formations 

of Emsian Age in the Rheinische Schiefergebirge 

(Groos and Jahnke, 1970; Stoltidis, 1971) or Ostthiiringen (Zagora, 1968) in Germany, nor from 

Emsian formations in the Salair district of Siberia 

(Polenova, 1968). 

Other Middle Devonian elements in the fauna are 

the forms closely related to Voronina inventa Rozhdestvenskaya, 1962, N eoaparchites? insericus (Rozhdestvenskaya, 1962), "Aparchites" auriculiferus 

Rozhdestvenskaya, 1962, Libumella discoides Rozhdestvenskaya, 1959, and Bairdiocypris? cordiformis 

Rozhdestvenskaya, 1959, all from beds considered to 

be Eifelian in Bashkiria, on the western slope of the 

Ural Mountains in the U.S.S.R. 

On the other hand, Early Devonian or older elements of the fauna are represented by such genera 

as Mesomphalus, Beyrichia (Beyrichia), Beyrichia 

(Scabribeyrichia), Parabolbina, N ewsomites, and 

Shidelerites. Beyrichia (Scabribeyrichia) and Shidelerites have not previously been reported from 

strata younger than Silurian; the other genera 

range from the Silurian into the early or middle 

Early Devonian (Gedinnian or Siegenian) but have 
8 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

not yet been reported from beds of Emsian Age. A 

form related to Praepilatina praepilata sibirica Polenova, 1970, from the upper Krekov beds in the 

Salair district of Siberia also suggests a Siegenian 

Age. The only Emsian element in the ostracode assemblage is the form closely related to Poloniella 

(Framella) scheii Weyant, 1968, from the lower 

part of the Blue Fiord Formation on Ellesmere 

Island, as this part of the formation is considered 

late Emsian by Boucot, Johnson, and Talent ( 1969, 

pl. 20). 

Although the ostracodes from Alaska and Yukon 

Territory show little affinity with any described Emsian ostracode fauna, late Early Devonian ostracodes have been relatively little studied in comparison with those from the Middle Devonian of the 

North American midcontinent region, Germany, 

Czechoslovakia, Poland, and Russia. Because the 

collections from which the ostracodes were obtained 

have been dated as Emsian on the basis of other 

groups of fossils, it is necessary to extend downward 

the ranges of at least seven genera not previously 

known below the Middle Devonian. The evidence 

from conodonts and dacryoconarid tentaculites that 

the McCann Hill collections are late Emsian and the 

Michelle and Prongs Creek collections are early 

Emsian suggests that many of the ostracodes described here have an undifferentiated Emsian range. 

This ostracode assemblage appears to represent a 

provincial fauna combining relict beyrichiaceans 

with ancestral hollinaceans and including elements 

that appeared later in widely separated areas. It will 

probably prove useful for Emsian correlation within 

the Arctic province. 

LIST OF LOCALITIES 

1. McCann Hill Chert, lower limestone and shale 

member. USGS collection 6492-SD, one-half mile 

west of Hillard Peak, 3.4 miles N. 41 oW. of International Boundary Commission monument 105, 

64°57'3" N., 141 °04'5" W., about 140 feet above 

base of McCann Hill Chert. USGS collection 7032-

SD, same locality as above but about 10 feet stratigraphically higher. USGS collection 7033-SD, 

same locality as above, composite sample from 

float material. USGS collection 7037-SD, from 

thin beds of limestone conglomerate in shale sequence, 300 feet east of USGS collection 6492-SD, 

64°57'2" N., 141 °4'9" W. USGS collection 7038-

SD, same locality as above, 5 feet above USGS 

collection 7037-SD. All collections from Eagle 

(D-1) quadrangle, Alaska, made by E. E. Brabb, 

1961, 1963. 

2. Michelle Formation. GSC locality 86588, Ludvigsen's sections II and III (fig. 2), east side of 

Blackstone River, 65°41.5' N., 137°26.5' W., Yukon Territory. Collections made by Rolf Ludvigsen. 

II-10; 260 feet below top of Michelle Formation. 

II-11; 200 feet below top of Michelle Formation. 

II-13; 160 feet below top of Michelle Formation. 

II-14; 100 feet below top of Michelle Formation. 

3. Michelle Formation. GSC locality 86589, Ludvigsen's section IV (fig. 2), south-facing ridge approximately halfway between Hart and Blackstone 

Rivers, 65°41' N., 137°01' W., Yukon Territory. 

Collections made by Rolf Ludvigsen. 

IV -3 ; 125 feet below top of Michelle Formation. 

4. Michelle Formation. GSC locality 86587, Ludvigsen's section I (fig. 2), west side of Hart River, 

65°38.2' N., 136°44' W., Yukon Territory. Collections made by Rolf Ludvigsen. 

I-3; about 75 feet above base of Michelle 

Formation. 

5. Prongs Creek Formation. GSC locality 86590, 

Ludvigsen's section V (fig. 2), Solo Creek, 65°51.4' 

N., 134°15.5' W., Yukon Territory. Collections 

made by Rolf Ludvigsen. 

V-3; 161 feet above Monograptus yukonensis. 

V -4; 196 feet above M. yukonensis. 

V -5; 305 feet above M. yukonensis. 

SYSTEMATIC PALEONTOLOGY 

Suprageneric classification of the Class Ostracoda 

is based largely on the "Treatise on Invertebrate 

Paleontology-Part Q, Arthropoda 3," edited by 

Moore (1961), except for the family Beyrichiidae, 

which is classified according to Martinsson (1962), 

and the superfamily Hollinacea, which is adopted 

from Bless and Jordan (1971). The terms used for 

morphologic features are based partly on the "Treatise," except for the terminology used for the beyrichiids, which follows that proposed by Martinsson 

(1962) and Henningsmoen (1965). Because this 

terminology is widely used by students of beyrichiids 

it seems desirable to use it here rather than to adhere to that of the "Treatise" ( 1961) for the sake of 

consistency. 

All measurements of specimens were made with a 

micrometer ocular. 

Abbreviations used for institutions from which 

collection or specimen numbers are cited are as follows: Geological Survey of Canada, GSC; U.S. Geological Survey, USGS; U.S. National Museum of 

Natural History, USNM. The section and collection 

numbers of Ludvigsen (1970) have been used to 

facilitate comparison with later papers by Fahraeus 

(1971) and Ludvigsen (1972). 
SYSTEMATIC PALEONTOLOGY 9 

Order P ALAEOCOPIDA Henningsmoen, 1953 

Suborder BEYRICHICOPINA Scott. 1961 

Superfamily BEYRICHIACEA Matthew, 1886 

Family BEYRICHIIDAE Matthew, 1886 

Subfamily CRASPEDOBOLBININAE Martinsson, 1962 

Genus MESOMPHALUS Ulrich and Bassler, 1913 

Mesomphalus? sp. 

Plate 1, figures 1, 2 

?Mesomphalus sp., Copeland in Ludvigsen, 1970, p. 426,427. 

Description.-Valves apparently subquadrate in 

lateral view; hinge straight. Anterior cardinal angle 

about 105°. Anterior margin smoothly rounded; 

venter straight; posterior margin unknown. Greatest height and length unknown. 

Valve surface papillose, papillae of uniform size. 

Trilobate, anterior lobe weakly developed, extending 

feebly to dorsum, separated from preadductorial 

node by a very low prenodal sulcus ; preadd uctorial 

node situated above midvalve and separated from 

syllobium by narrow, shallow, posteriorly convex 

adductorial sulcus. Syllobium unknown. Ventral part 

of valve dissected by obliquely curved longitudinal 

fissus extending from beneath preadductorial node 

posteriorly for unknown distance. Prominent velar 

ridge separated from domicilium by pronounced 

groove paralleling free margin ; velar ridge separated from incomplete marginal ridge by narrow 

groove. Marginal ridge composed anteriorly and 

posteriorly of short denticles or spines, none ventrally. 

Material.-Two incomplete tecnomorphic valves. 

Measurements.-Length of figured specimen GSC 

29438, 1.8 mm; height of figured specimen GSC 

29439, 1.25 mm. 

Types.-Figured specimens, GSC 29438, 29439. 

Discussion.-These specimens appear somewhat 

similar to M esomphalus hartley-i Ulrich and Bassler, 

1913, as figured by Kesling and Rogers (1957, pl. 

130, figs. 11-15). The marginal spines of the present 

specimens are more acuminate, and the preadductorial node apparently is in a more dorsal position. 

Without complete tecnomorphic and, more important, 

complete heteromorphic valves these specimens cannot be placed unequivocally within M esomphalus. 

Martinsson ( 1962, p. 188-190) has indicated the 

similarity of the Devonian genus M esomphalus to 

the Silurian genus Clintiella Martinsson, 1962. From 

the literature it appears, however, that differences 

exist between these genera based on velar and marginal structures. Cruminal differentiation is unknown. 

Occurrence.-Ludvigsen collection V -3, Prongs 

Creek Formation, Solo Creek, Yukon Territory. 

Subfamily TREPOSELLINAE Henningsmoen, 1954 

Genus TREPOSELLA Ulrich and Bassler, 1908 

Treposella borealis n. sp. 

Plate 1, figures 5-10 

Treposella sp., Berdan in Churkin and Brabb, 1968, table 1, 

pl. 4, figs. 16, 17. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426. 

Description.-Lateral outline amplete to preplete. 

Preadductorial lobe outlined by shallow indistinct 

prenodal sulcus; adductorial sulcus deep, narrow, 

widest at ventral end. Syllobium cuspate; cusp protrudes above hinge line. Fissus on syllobium connects 

with prenodal sulcus to form groove concentric to 

free margin. Velar ridge distinct, extends completely 

around free margin. Surface reticulate except for 

velar ridge and adductorial sulcus. Crumina ventral, 

elongate ovate, very finely punctate. Velar edge 

crosses crumina with two treposelline bridges; interior of crumina with strut about middle of length. 

M aterial.-Fourteen specimens from Alaska, one 

specimen from Yukon. 

M easurements.-The holotype, a heteromorphic 

valve, measures 2.35 mm in length and 1.50 mm in 

height. A paratype tecnomorphic valve measures 

2.25 mm in length and 1.43 mm in height. 

Types.-Holotype, USNM 170352; paratypes, 

USNM 170351, 173730, 173731, GSC 29453. 

Discussion.-Treposella bo'realis differs from T. 

lyoni (Ulrich, 1891), the type species of Treposella, 

in having a less prominently cuspate syllobium and 

in having a punctate rather than striate crumina. 

It differs from T. stellata Kesling, 1955, in having 

only one fissus across the syllobium and no crista on 

the crumina. The morphology of the ventral surface 

of the crumina ofT. borealis resembles that of Garniella Martinsson, 1962, as illustrated by Martinsson 

(1962, text fig. 89B). The dolonoid scar of Treposella 

lyoni, described by Martinsson (1962, p. 211-214) 

from the illustrations of Kesling and Rogers (1957, 

pl. 127, fig. 3), has not been observed on our specimens of T. borealis. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, from the McCann Hill Chert, Eagle 

(D-1) quadrangle, Alaska; Ludvigsen collection 

V -3, from the Prongs Creek Formation, Solo Creek, 

Yukon Territory. 

Treposella sp. cf. T. lyoni (Ulrich, 1891) 

Plate 1, figures 3, 4 

Discussion.-Two small tecnomorphic specimens 

with the lobation of Treposella lyoni (Ulrich, 1891) 

and coarser reticulation than T. borealis n. sp. have 

been found in the McCann Hill Chert. These specimens have the cuspate, vertically divided syllobium 
10 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

of T. lyoni but differ from that species in having a 

very reduced velar ridge. Because the only two specimens found are probably immature individuals, an 

unequivocal specific assignment is not possible. 

Measurements.-The figured specimen (pl. 1, fig. 

3) is 0. 75 mm long and 0.45 mm high. 

Types.-Figured specimens, USNM 173728, 

173729. 

Occurrence.-USGS collection 7037-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Subfamily BEYRICHIINAE Matthew, 1886 

Genus BEYRICHIA M'Coy, 1846 

Subgenus BEYRICHIA M'Coy, 1946 

Beyrichia (Beyrichia) brabbi n. sp. 

Plate 2, figures 1-8 

Beyrichia (Beyrichia) sp. A, Berdan in Ghurkin and Brabb, 

1968, table 1, pl. 4, figs. 11, 12. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426, 427. 

Description.-Lateral outline. preplete to amplete. 

Anterior lobe broad; prenodal sulcus distinct, inclined posteriorly and tending to isolate pyriform 

preadductoriallobe. Adductorial sulcus deep, curved 

anteriorly, extending half or more than half height 

of valve. Syllobium broad, undivided. Anterior cusp 

developed as spine; two posterodorsal spinose cusps 

on syllobium, widely separated, diverging at angle 

of about 40°. Velar ridge distinct, spinose. Surface 

covered with spines or pustules except for sulci and 

small field dorsal to adductorial sulcus, preadductorial lobe, and prenodal sulcus, in which are only 

two small spines, one dorsal to adductorial sulcus 

and one dorsal to preadductoriallobe. Finely granulose ornamentation superimposed on pustulose ornam.entation. Crumina of heteromorph large, ovate, 

anteroventral, distinctly set off from domicilium, 

bounded posteriorly by adductorial sulcus. Ornamentation of crumina like that of domicilium except that 

pustules are smaller on ventral surface. Trace of 

velar ridge across ventral surface of crumina indicated by row of small pustules or spines. 

Material.-More than 40 specimens from the McCann Hill Chert, more than 3 specimens from 

the Michelle Formation, and more than 6 specimens 

from the Prongs Creek Formation. 

Measurements.-The holotype, a heteromorphic 

right valve, measures 2.6 mm in length and 1.5 mm 

in height. A tecnomorphic right valve, a paratype, 

measures 2.5 mm in length and 1.5 mm in height. 

Measurements of 27 specimens from the McCann 

Hill Chert (USGS colin. 6492-SD) are shown in 

figure 3. 

Types.-Holotype, USNM 170346; para types, 

USNM 170347, 173732, 173733, 173734, 173735, 

173736, GSC 29473, 29474. 

Discussion.-This species is similar to Beyrichia 

(Beyrichia) arctigena Martinsson, 1960 in its undivided syllobium, the size and position of the crumina, and the presence of the two small spines above 

the adductorial sulcus and preadductoriallobe. However, unlike Beyrichia (Beyrichia) brabbi, B. (B.) 

arctigena is only very sparsely pustulose. In addition, the syllobial cusps of B. (B.) arctigena are 

closer together than those of B. (B.) brabbi. Both 

species differ from all other species assigned to 

Beyrichia in having undivided syllobia (Martinsson, 

1960, p. 17). The species is named for Earl E. Brabb 

of the U.S. Geological Survey, who collected the first 

specimens. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD from the McCann Hill Chert, Eagle 

(D-1) quadrangle, Alaska; Ludv:_igsen collection 

11-11 from the Michelle Formation, Blackstone 

River, Yukon Territory; Ludvigsen collections V-3 

and V-4, from the Prongs Creek Formation, Solo 

Creek, Yukon Territory. 

Subgenus SCABRIBEYRICHIA Martinsson, 1962 

Beyrichia (Scabribeyrichia) churkini n. sp. 

Plate 3, figures 1-9 

Beyrichia (Beyrichia) sp. B, Berdan in Churkin and Brabb, 

1968, table 1, pl. 4, figs. 13, 14. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426, 427. 

Description.-Latera1 outline preplete to amplete. 

Anterior lobe broad; prenodal sulcus narrow, distinct, curved posteriorly beneath preadductoriallobe. 

Preadductorial lobe subpyriform, slanted posteriorly; adductorial sulcus wide, extending about half 

height of valve. Syllobium wide, divided by sinuate 

curving fissus or syllobial groove which joins prenodal sulcus beneath adductorial sulcus and preadductorial lobe at angle of approximately 90°. Velar 

ridge narrow, spinose. Anterior lobe cuspate; two 

closely spaced spinose cusps on syllobium. Entire 

surface except for sulci covered with closely spaced, 

prominent tubercles, four of which tend to merge to 

form calcarine spine. Crumina large, ovate, anteroventral, pustulose. Tubercles on ventral surface of 

crumina not markedly different from those on domicilium except for row of small tubercles marking 

trace of velar ridge. 

M aterial.-More than 60 specimens from the McCann Hill Chert; more than 15 specimens from the 

Michelle Formation; more than 30 specimens from 

the Prongs Creek Formation. 

Measurements.-The holotype, a heteromorphic 

left valve, is 2.80 mm long and 1.55 mm high. A 

paratype tecnomorphic left valve is 2.60 mm long 
S·YSTEMAT'IC PALEONTOLOGY 11 

2.0,-------------~~------------~~------------~~------------~~------------~ 

rn 

a: 

w 

1-

w 1.5 ~ 

J 

...J 

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~ 

..... 

:r 

C) 

w 

:r 

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-

-

EXPLANATION 

• 

Tecnomorphic specimen 

Heteromorphic specimen 

Two specimens with 

identical measurements 

• 

• • 

• 

•• 

• 

•• 

• 

• 

• • 

• • . f ' 

• 

-

-

0.5~----------~7-'----------~~~------------L-'------------L~------------~ 0.5 1 .0 1.5 2.0 2.5 3.0 

MAXIMUM LENGTH, IN MILLIMETERS 

FIGURE 3.-Scatter diagram of maximum length versus maximum height for Beyrichia (Beyrichia) brabbi n. sp.; 27 specimens from the McCann Hill Chert (USGS colin. 6492-SD, paratype slide USNM 173735). 

and 1.55 mm high. Measurements of 57 specimens 

from the McCann Hill Chert are shown in figure 4. 

Types.-Holotype, USNM 170349 ; paratypes, 

USNM 170348, 173737, 173738, 173739, GSC 29469, 

294 70, 294 71, 294 72. 

Discussion.-This species is here placed in the 

subgenus Scabribeyrichia Martinsson, 1962, because 

of the characteristic zygal arch outlined by the junction of the fissus or syllobial groove with the prenodal sulcus. Although it superficially resembles 

species of Eobeyrichia Henningsmoen, 1954, as illustrated by Henningsmoen (1954, p. 21, pl. 1), Eobeyrichia has a fissus on the anterior lobe as well as on 

the syllobium. Beyrichia (Scabribeyrichia) churkini 

resembles the form described by Martinsson ( 1962, 

p. 301-302, fig. 165B, 165C) as Beyrichia (aff. Scabribeyrichia) sp., from the Wenlock of Gotland, but 

the North American species has a narrower, more 

distinct fissus and sharper cusps. It differs from 

other described species of Scabribeyrichia, such as 

Beyrichia (Scabribeyrichia) foliosa (Jones, 1888), 

in being more pustulose. This species is named for 

Michael Churkin, Jr., who has collected and studied 

the McCann Hill Chert fauna. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, 7038-SD, from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen 

collection 11-11, Michelle Formation, Blackstone 

River, Yukon Territory; Ludvigsen collections V -3, 

V -5, Prongs Creek Formation, Solo Creek, Yukon 

Territory. 

Genus YUKONIBEYRICHIA n. gen. 

Type species.-Yukonibeyrichia yukonensis n. sp. 

Species included.-Yukonibeyrichia solon. sp. 

Diagnosis.-Beyrichiine ostracodes with wide, 

flattened anterior supravelar field sharply set off 

from remainder of domicilium. Prenodal sulcus weak 

to obsolete so that anterior lobe and preadductorial 

lobe tend to merge. Adductorial sulcus wide and 

deep. Syllobium with single cusp, with or without 

fissus. Crumina of heteromorph inflates and obliterates anterior supravelar field and occupies anteroventral part of domicilium up to prenodal sulcus. 

Ornamentation pustulose. 

Discussion.-The lobation of this distinctive 

genus superficially resembles that of a hollinid 

rather than a beyrichiid, but the cruminal dimorph-
12 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

2.0~------------~,--------------~,------------~,--------------~~------------. 

(/l 

a: 

w 

1-

w 1.5 r- :2: 

...J 

...J 

:2: 

~ 

1-. 

I 

~ w 

I 

:2: 

:J 1.0 :2: ....__ 

X 

<( 

:2: 

EXPLANATION 

• 

Tecnomorphic specimen 

Heteromorphic specimen 

Two specimens with 

identical measurements 

• 

• I 

• •• •• 

• • • • 

II!• 

• 

• • • • • 

• 

• • 

• • • 

• 

-

_-

I I I I O.~L.S--------------~1.L0---------------1~.5----------------2~.0~------------~2.~5---------------3~.0 

MAXIMUM LENGTH, IN MILLIMETERS 

FIGURE 4.-Scatter diagram of maximum length ve.rsus maximum height for Beyrichia (Scabribeyrichia) c.hurkini n. sp.; 

57 specimens from the McCann Hill Chert (USGS coli. 6492-SD, paratype slide USNM 173739). 

ism indicates that it belongs with the latter group. 

It is apparently a late development of the line of 

Beyrichia s. s. The generic name is derived from 

Yukon Territory and the Yukon River area where 

it is found. 

Geologic range.--As yet this genus is known only 

from the Lower Devonian of Alaska and Yukon Territory. 

Yukonibeyrichia yukonensis n. sp. 

Plate 4, figures 5-11 

Beyrichiid, n. gen., n. sp., Berdan in Churkin and Brabb, 

19·68, pl. 4, fig. 10. [Imprint 19·67.] 

Description.-Lateral outline preplete; dorsal 

margin straight; anterior cardinal angle distinct; 

anterior margin curved smoothly into gently curved 

ventral margin; posterior margin gently curved ; 

posterior cardinal angle more acute than anterior 

angle. Wide supravelar field extends anterodorsally 

around anterior lobe and preadductorial lobe to adductorial sulcus. Prenodal sulcus weak; preadductorial lobe pyriform, only slightly separated from 

small arcuate anterior lobe. Adductorial sulcus wide 

and deep. Syllobium large, with shallow fissus. Anterior cardinal angle cuspate; anterodorsal cusp on 

supravelar field dorsal to prenodal sulcus. Dorsal 

tubercle on cusp on syllobium; uncular tubercle on 

posterior supravelar field below posterior cardinal 

angle. Small tubercle near dorsum above adductorial 

sulcus. Supravelar field granulose to weakly papillose; remainder of domicilium strongly pustulose 

except for sulci and fissus. Crumina pustulose like 

domicilium. Velar ridge apparently crosses ventral 

surface of crumina without deflection. 

Material.--Twenty-three valves from the McCann 

Hill Chert; more than three specimens from the Michelle Formation ; more than 20 specimens from the 

Prongs Creek Formation. 

Measurements.--The holotype, a large tecnomorphic left valve, is 2.80 mm long and 1.60 mm high. 

Another tecnomorphic left valve (USNM 173742) 

from the McCann Hill Chert is 2.60 mm long and 

1.35 mm high. Measurements of 20 specimens from 

the McCann Hill Chert are shown in figure 5. 

Types.-Holotype, GSC 29432, paratypes, GSC 

29433, 29434, USNM 170345, 173740, 173741, 

173742, 173743, 173744. 

Discussion.-This species is characterized by its 

pustulose surface and prominent anterodorsal cusp. 
S.YS.TEMATIC PALEONTOLOGY 13 

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FIGURE 5.-Scatter diagram of maximum len,gth versus maximum height for Yukonibeyrichia yukonensis n. sp.; 20 specimens from the McCann Hill Chert (USGS coHn. 6492-SD, paratype slide USNM 173743; USGS coHn. 7032-SD, paratype slide USNM 173744). 

The uncular tubercle is also characteristic, although 

there is some variation in its relative size. The position of the uncular and other tubercles appears to 

be constant throughout the ontogeny of the species, 

but it is more prominent on immature specimens 

and better developed on specimens from the McCann Hill Chert than on specimens from the Prongs 

Creek Formation. The name of the species is based 

on its occurrence in the Yukon River Valley and 

Yukon Territory. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, from the McCann Hill Chert, Eagle 

(D-1) quadrangle, Alaska; Ludvigsen collections 

II-11, II-14, from the Michelle Formation, Blackstone River, Yukon Territory; Ludvigsen collections 

V -3, V -4, V -5, from the Prongs Creek Formation, 

Solo Creek, Yukon Territory. 

Yukonibeyrichia solo n. sp. 

Plate 4, figures 1-4 

Description.-Lateral outline preplete; anterior 

cardinal angle distinct. Anterior margin curved 

smoothly into gently curved ventral margin; posterior margin smoothly curved. Supravelar field wide 

anterodorsally, extends dorsally around end of anterior and preadductoriallobes to adductorial sulcus. 

No cusps or prominent tubercles on supravelar field. 

Prenodal sulcus obsolete, so that anterior and preadductorial lobes are fused. Adductorial sulcus wide 

and deep. Syllobium lacking fissus; syllobium has 

one blunt cusp which lacks prominent tubercle. Surface of domicilium with low pustules except for 

supravelar field, which is granulose. Crumina pustulose like domicilium; velar ridge appears to cross 

ventral surface of crumina as slightly sinuous line. 

Antrum or groove between velar ridge and marginal 

ridge partly constricted beneath crumina. 

Mat erial.-Three specimens from the Prongs 

Creek Formation. 

Measurements.-The holotype, a tecnomorphic 

right valve, is 2.30 mm long and 1.30 mm high. Paratype GSC 29436, a carapace, is 2.20 mm long and 

1.30 mm high. 

Types.-Holotype, GSC 29435; para types, GSC 

29436, 29437. 

Discussion.-Yukonibeyrichia solo differs from Y. 

yukonensis in the complete obsolescence of the prenodal sulcus, the lack of a fissus on the syllobium, 

and especially in the lack of the anterodorsal cusp, 

the uncular tubercle, and the tubercle above the adductorial sulcus. Although only three specimens have 

been found, the consistent character of the cusps and 

tubercles in several instars of Y. yukonensis suggests that the specimens lacking the anterodorsal 
14 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

cusp belong to a distinct and different species. The 

name of the species is derived from Solo Creek, 

Yukon Territory. 

Occurrence.-Ludvigsen collections V -3 and V -4, 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Subfamily indet. 

Genus ALASKABOLBINA n. gen. 

Type species.-Alaskabolbina unilineata n. sp. 

Species included.-Alaskabolbina bilineata n. sp., 

Alaskabolbina nodilineata n. sp. 

Diagnosis.-N onsulcate .paleocope ostracodes with 

central bulb or node and with anterodorsal and posterodorsal cusps or spines. Velum tubulous, incomplete, extending from anterior cardinal angle to 

posteroventral slope, ending in hollow spine. Domiciliar ornamentation pustulose. Ridge or ridges 

(torus?) on subvelar field parallel to free margin. 

Heteromorph not known. 

Discussion.-The tubulous velum of Alaskabolbina 

suggests beyrichiid or eurychilinid affinities, but 

until heteromorphs are found, the systematic position and relationship of this genus cannot be determined. The conspicuous bulb, which occupies the 

position of the median sulcus in other ostracodes, is 

similar to that of the Late Ordovician chilobolbinid 

genus Cystomatochilina Jaanusson, 1957, but Alaskabolbina lacks any trace of a median pit, and the 

velum does not extend around the entire free margin. Alaskabolbina may be related to the nonsulcate 

craspedobolbinine genera Apatobolbina Ulrich and 

Bassler, 1923, Leptobolbina Martinsson, 1962, and 

Schohariella Berdan, 1971, but these genera lack the 

median bulb. The name of the genus is derived from 

its occurrence in Alaska combined with -bolbina, in 

reference to the characteristic median swelling. 

Geologic range.-As yet this genus is known only 

from the Lower Devonian of Alaska and Yukon 

Territory. 

Alaskabolbina unilineata n. sp. 

Plate 5, figures 13-15 

Description.-Lateral outline amplete to slightly 

preplete. Large subcircular median node above midheight of valve. Median node verrucose, subconical 

in profile. Massive blunt verrucose anterodorsal and 

posterodorsal cusps protrude above hinge line. Surface finely papillose, with scattered tubercles arranged concentrically around median node; one large 

tubercle above node and between two dorsal cusps. 

Striated velum extending from anterodorsal angle to 

posterior part of free margin, ending in upward 

recurved spur. Velum curved away from contact 

margin in ventral view; subvelar field crossed by 

single finely denticulate toric ridge parallel to free 

margin. Heteromorph not known. 

M aterial.-One right valve, and a few fragments 

from the McCann Hill Chert. 

Measurements.-The holotype and only specimen 

is 1.70 mm long and 0.90 mm high. 

Types.-Holotype, USNM 1737 45. 

Discussion.-Although only one relatively complete specimen of this species has as yet been found, 

it is so distinctive that a specific name seems justified. It differs from other species of Alaskabolbina 

in having heavier dorsal cusps, a single toric ridge, 

and in being more sparsely papillose. 

Occurrence.-USGS collection 6492-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, 

Alaska. 

Alaskabolbina bilineata n. sp. 

Plate 5, figures 16--21 

Description.-Later~l outline amplete. Valve nonsulcate, with large subcircular median node at or 

slightly above center of valve. Domicilium cuspate 

at both ends; cusps spinose, extending above dorsal 

margin. Surface papillose, with scattered tubercles 

surrounding central node and distributed over valve 

surface. Striated velum extending from anterodorsal 

angle ( ?) to posterior part of free margin, ending in 

tubulous spur. In ventral view, velum bowed outward near midvalve, in contact anteriorly and posteriorly with double torus; toric ridges parallel to 

and at some distance from marginal ridge. 

Material.-Five specimens from the Michelle Formation. 

Measurements.-The holotype is 1.80 mm long and 

1.00 mm high. 

Types.-Holotype, GSC 29464; paratypes, GSC 

28465, 29466, 29467, 29468. 

Discussion.-This species differs from Alaskabolbina unilineata, the type species, in having spinose 

rather than nodose dorsal cusps, more tubercles on 

the surface of the valve and double subvelar toric 

ridges rather than a single denticulate torus. 

Occurrence.-Ludvigsen collection II-11, from the 

Michelle Formation, Blackstone River, Yukon Territory. 

Alaskabolbina nodilineata n. sp. 

Plate 5, figures 1-6 

Description.-Lateral outline amplete. Valves nonsulcate, with large subcircular median node above 

center of valve. Valves with wide anterior extralo-
SYSTEMATIC PALEONTOLOGY 15 

bate area. Valves with larger tubercles in position of 

cusps, extending above dorsal margin. Surface papillose with numerous scattered tubercles surrounding 

and encroaching on median node, extra-lobate area 

with few tubercles. Striated velum extending from 

midanterior to posterior part of free margin, ending in spur. In ventral view, velum bowed outward 

near midvalve, with subvelar area convex and traversed by double row of tubercles (torus?) parallel 

with free margin. Interior with deep impressions of 

central node and anteroventral lobe reminiscent of 

crumina. 

Mat erial.-Two specimens from Prongs Creek 

Formation. 

Measurements.-The holotype is 1.20 mm long and 

0.60 mm high. 

Types.-Holotype, GSC 29512; para type, GSC 

29513. 

Discussion.-This species differs from Alaskabolbina unilineata in having a large anterior extralobate area, in being more pustulose, and in having 

a double row of subvelar tubercles as a toric structure in the position of the single denticulate torus 

of A. unilineata. It differs from A. bilineata in having a large anterior extralobate area, in being more 

pustulose, and in having a double row of subvelar 

tubercles instead of a double ridge as in A. bilineata. 

The two valves which represent this species may 

be heteromorphic, but this is not certain. The ventral 

obesity of the specimens in lateral view, the convex 

nature of the subvelar field and the depth of the 

ventral lobate area in interior view suggest this possibility. However, they are not heteromorphs of 

either Alaskabolbina unilineata or A. bilineata because of the differences in the character of the ornamentation. 

Occurrence.-Ludvigsen collection V -3 from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Alaskabolbina sp. 

Plate 5, figure's 11, 12 

Discussion.-Two small specimens (USNM 

173844, 173845) from the McCann Hill Chert (USGS 

colln. 7037-SD) are apparently immature tecnomorphs of a species of Alaskabolbina. They have the 

prominent dorsal cusps and median bulb characteristic of the genus, but the velum of both specimens 

is relatively short and the torus is poorly developed, 

making it impossible to assign them to any of the 

described species. The flaring velum of the larger 

specimen (USNM 173845, pl. 5, fig. 12) is like that 

of A. nodilineata n. sp., but the dorsal cusps are not 

as well developed in that species. The smaller specimen is 0.55 mm long and 0.30 mm high; the larger 

specimen is 0.80 mm long and 0.40 mm high. 

Alaskabolbina? sp. 

Plate 5, figures 7-10 

Discussion.-Four small specimens which appear 

to be related to Alaskabolbina have been found in the 

McCann Hill Chert (USGS colin. 7037-SD). These 

have the median bulb of Alaskabolbina, but lack dorsal cusps and are less papillose than any of the species here assigned to the genus. Two of the figured 

specimens, USNM 173840 (pl. 5, fig. 7) and USNM 

173841 (pl. 5, fig. 8), have short vela which are bent 

almost perpendicularly to the plane of commissure; 

one, USNM 173842 (pl. 5, fig. 9), which is otherwise 

similar, has a longer and less recurved velum. The 

fourth figured specimen, USNM 173843 (pl. 5, fig. 

10), has a short but not recurved velum and is more 

papillose than the others. These specimens are probably immature forms of two or more species of 

which the adults are as yet unknown. The material 

is not adequate for a formal description, but is illustrated here to show the variety of the ostracode 

fauna. 

Superfamily DREPANELLACEA Ulrich and Bassler, 1923 

Family indet. 

Genus OGIL VITES n. gen. 

Type species.-Ogilvites bicornis n. sp. 

Species included.-K noxites argutula Zaspelova, 

1959. 

Diagnosis.-Small, straight-backed, bilobate drepanellids with prominent S2. Lobes coarsely reticulate; ventral part of valves with striae parallel to 

free margin and/ or reticulae. Velar bend parallel to 

free margin ; free margin smooth. 

Discussion.-The prominent, centrally located, 

nearly equal dorsal lobes of this genus distinguish it 

from other drepanellids. The position and types of 

ornamentation are likewise distinctive. The name of 

the genus is derived from the Ogilvie Mountains, 

eastern Yukon Territory, where it occurs. 

Geologic range.-Lower Devonian, Yukon Territory; Upper Devonian (Frasnian), U.S.S.R. 

Ogilvites bicornis n. sp. 

Plate 6, figure 1 

Description.-Valves subovate in lateral view, 

bilobate. Dorsum straight; free margins evenly 

rounded; cardinal angles curved. Left ( ?) valve 

slightly overlapping right ( ?) around free margin. 
16 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRIT'ORY 

Prominent 82 extends from dorsal margin to midvalve. Lobation consists of two conical tubercles, one 

on either side of 82, which extend well above hinge 

line. Tubercles reticulate with prominent ridges ; 

about 10 meshlike polygons on each. Reticulae on 

tubercles limited ventrally by ridge extending beneath 82 and dying out at anterior and posterior 

edges of reticulation. 

Ventral part of valve with five ridges paralleling 

free margin. Most dorsal ridge, mentioned above, 

limits tubercular reticulation; second ridge extends 

uninterruptedly to each cardinal angle ; third ridge 

only as long as most dorsal ridge and branches medially into several reticulae ; fourth ridge extends 

to each cardinal angle and branches near midvalve 

to form reticulae; fifth ridge borders entire margin 

of valve as velar bend ; marginal area smooth. 

M aterial.-One complete carapace from the 

Prongs Creek Formation. 

Measurements.-The holotype carapace is 0.9 mm 

long. The height to the hinge line is 0.60 mm; the 

height to the tip of the dorsal tubercles is 0.65 mm .. 

Types.-Holotype, GSC 29454. 

Discussion.-This species differs from Ogilvites 

argutula ( Zaspelova, 1959) from post-Snezha beds 

in the Novgorod district, U.S.S.R., in having more 

prominent dorsal tubercles wth reticulae more uniform in size and distribution. Both species have a 

similar type of surface ornamentation (Zaspelova, 

1959, pl. 8, figs. 7a, b), but 0. argutula has a more 

prominent velar flange rather than a velar bend as 

in 0. bicornis. 

Occurrence.-Ludvigsen collection V -3, Prongs 

Creek Formation, Solo Creek, Yukon Territory. 

Superfamily HOLLINACEA Swartz, 1936 

Family CTENOLOCULINIDAE Jaanusson and Martinsson, 1956 

Subfamily CTENOLOCULININAE Jaanusson and Martinsson, 1956 

Genus ABDITOLOCULINA Kesling, 1952 

Abditoloculina dausa n. sp. 

Plate 6, figures 2-8 

Abditoloculina sp., Berdtan in Ghurkin and Brabb, 1968, 

table 1, pl. 4~ fig. 3. [Imprint 1967.] 

Description.-Lateral outline amplete to preplete. 

L1 projecting as cusp above hinge line; L2 rounded 

node below hinge line; L3 rounded node about same 

size as L2 but set higher on valve. S1 weak; S2 deep, 

narrow, confined to dorsal third of valve. Prominent 

median spurlike node beneath S2, below and between 

L2 and L3. Two posterior tubercles, one just ventral 

to posterior cardinal angle, second in posteroventral 

quarter of valve beneath first tubercle. Tecnomorph 

with anterior node at or slightly above midheight on 

anterior margin; velum extends from node posteroventrally to posterior third of valve. Anteroventral 

spur above but merging with velum. Heteromorph 

with six loculi extending from anterior node to posterior third of valve; anteroventral spur on third 

loculus. Loculi closed in ventral view (pl. 6, fig. 4). 

Surface finely granulose. 

M aterial.-Seven tecnomorphic and 3 heteromorphic carapaces, and more than 10 valves from the 

McCann Hill Chert. 

Measurements.-The holotype, a heteromorphic 

carapace, is 0.90 mm long, 0.50 mm high, and 0.50 

mm wide, including the spur. A tecnomorphic carapace (USNM 173746) is 0.90 mm long, 0.47 mm 

high, and 0.50 mm wide. There is little variation in 

size of individuals. 

Types.-Holotype, USNM 170338; paratypes, 

USNM 173746, 173747, 173748, 173749. 

Discussion.-Kesling and Peterson (1958, p. 130) 

concluded that species of Abditoloculina may be discriminated by the number of loculi present in the 

heteromorphs. A. clausa differs from the 14 previously described species of Abditoloculina in having 

only 6 loculi; the lowest number previously recorded 

was 7 for the type species of the genus, A. insolita 

Kesling, 1952, and for A. binodata Kesling and 

Peterson, 1958. In addition, unlike any of the other 

species, the loculi of A. clausa are closed in ventral 

view (pl. 6, fig. 4) ; that is, in a complete carapace 

with the valves in contact, no locular openings can 

be seen. The adult tecnomorph of A. clausa differs 

from those of other species in having relatively subdued spurs and a well-developed velum. This species is similar to A. binodata in having two posterior 

tubercles. The name of the species is derived from 

the Latin clausus, -a, -u1n, referring to the closed 

loculi. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, and 7033-SD from the McCann Hill Chert, 

Eagle (D-1) quadrangle, Alaska. 

Abditoloculina dausa? 

Plate 6, figure 9 

Description.-Lateral outline preplete. L1 projecting as cusp above hinge line ; L2 rounded node below hinge line; L3 rounded node about same size as 

L2 but set higher on valve. S2 wide and deep. Prominent median spur beneath S2, below and between L2 

and L3. Two posterior tubercles, one just below posterior cardinal angle, second in posteroventral quarter of valve beneath first tubercle. Anterior node at 

or slightly above midheight on anterior margin. 

Anteroventral posteriorly curved spur in anterior 

third of valve, on anteroventral margin. 
SYSTE-MAT'IC PAL,EONTOLOGY 17 

Material.-Three tecnomorphic right valves from 

the McCann Hill Chert. 

Measurements.-The figured specimen is 0.70 mm 

long and 0.40 mm high. 

Types.-Figured specimen, USNM 173750. 

Discussion.-The lobation of these three valves resembles that of tecnomorphs of Abditoloculina 

clausa n. sp. except for the pronounced median and 

anteroventral spurs; they also differ in lacking a 

well-defined velum. The spurs are suggestive of A. 

binodata Kesling and Peterson, 1958, but the tecnomorph of A. binodata has not been described. They 

may possibly be immature tecnomorphs of A. clausa 

if the trimorphic concept (Bless and Jordan, 1971, 

1972) is substantiated. However, this material is not 

adequate either to prove or disprove the trimorphic 

concept. 

Occurrence.-USGS collections 7033-SD, 7037-

SD, and 7038-SD from the McCann Hill Chert, 

Eagle (D-1) quadrangle, Alaska. 

Subfamily PARABOLBININAE Bless and Jordan, 1971 

Genus PARABOLBINA Swartz, 1936 

Parabolbina sp. 

Plate 8, figures 17, 18 

Description.-Carapace elongate, slightly preplete, 

trilobate. Dorsal border straight; anterior border 

subround; ventral border gently convex; posterior 

border tapering, subround. Anterior cardinal angle 

abrupt, more than 90°; posterior cardinal angle 

acuminate. All lobes confluent with ventral inflation. 

L1 low, nearly merged with small L2; L3 broad, occupying posterior half of valve, separated anteriorly 

from L2 by deep geniculate S2 extending from dorsum and ending abruptly near midvalve. Lateral surface ornamented with papillae of various sizes, free 

border smooth. Spurs located at anteroventral and 

posteroventral parts of valve, large, blunt, ends 

broken. Anterior spurs flattened and closer to free 

margin than posterior spurs. 

Material.-One tecnomorphic carapace from the 

Michelle Formation. 

Measurements.-The figured specimen is 0.93 mm 

long, 0.52 mm high, and 0.50 mm wide. 

Types.-Figured specimen, GSC 29449. 

Discussion.-This possibly immature specimen is 

somewhat similar to Parabolbina pulchella Kesling 

and McMillan, 1951, from the Bell Shale of Michigan, but lacks a tuberculate free border. P. hypercala Kesling and Tabor, 1953, from the Genshaw 

Formation of Michigan is more papillose and has 

L3 more pronounced. P. granosa (Ulrich, 1900), the 

type species of the genus, has smaller spurs and a 

less distinct L2. 

Occurrence.-Ludvigsen collection II-10, from the 

Michelle Formation, Blackstone River, Yukon Territory. 

Family HOLLINIDAE Swartz, 1936 

Subfamily HOLLININAE Swartz, 1936 

Genus HOLLINA Ulrich and Bassler, 1908 

Hollina sp. 

Plate 6, figure 23 

Description. - Lateral outline amplete; hinge 

straight; cardinal angles obtuse. Free margins 

evenly rounded. L1large, vertically elongate parallel 

to anterior border, terminating near middle of anteroventral part of valve; L2 is small node; L3 is 

large bulb; L4 narrow, vertically elongate, smaller 

than Ll. S1 narrow, somewhat sinuous; S2 deep, 

particularly in dorsal half of valve, sinuous, dorsally 

confluent with S1, passing between L2 and L3 and 

between two ventral lobes ; S3 deep, vertical. All 

sulci reach ventral border. Two large ventral lobes, 

anterior one nodelike, ventral of L2, posterior one 

elongate-triangular, knoblike, ventral of L3. Marginal tubercles on ridge or bend parallel with entire 

free margin; tubercles of ventral part larger. Entire 

surface covered with papillae, those on lobes being 

larger than those in sulci. 

M aterial.-One tecnomorphic right valve. 

Measurements.-The figured specimen is 1.50 mm 

long and 0. 93 mm high. 

Types.-Figured specimen, GSC 29441. 

Discussion.-This specimen appears to represent 

a species which is similar to Hollina insolens (Ulrich, 1900) and H. pyxidata Kesling, 1953. Both of 

those species, however, have a different arrangement 

of the two ventral lobes, which project as spurs, and 

L1 and L4 are more nodelike and L2 is smaller. Also, 

H. pyxidata is more posteriorly acuminate. H. compressa Kesling and Peterson, 1958, has a flatter 

valve surface and elliptical spurs. 

Occurrence.-Ludvigsen collection V -3, Prongs 

Creek Formation, Solo Creek, Yukon Territory. 

Subfamily F ALSIPOLLICINAE Bless and Jordan, 1971 

Genus FALSIPOLLEX Kesling and McMillan, 1951 

Falsipollex? multispinosus n. sp. 

Plate 7, figures' 14-16 

Description.-Lateral outline amplete. Hinge line 

straight; anterior margin curved ; ventral margin 

less curved; posterior margin smoothly curved. L1 

subdued, separated from L2 by short, shallow Sl. 

L2 small, rounded; L3 bulbous, separated from 

ventral lobe by shallow groove. Velum in tecnomorph replaced by row of spines; velum in hetero-
18 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

morph forms an anteroventral, elongate elliptical 

dolonal pouch. Surface covered with fairly long 

blunt spines except for sulci. Ornamentation between 

spines finely granular. 

M aterial.-One heteromorphic right valve, one 

broken heteromorphic left valve, and one broken 

tecnomorphic left valve, all from the McCann Hill 

Chert. 

Measurements.-The holotype is 1.80 mm long and 

1.05 mm high. 

Types.-Holotype, USNM 173761 ; para types, 

USNM 173762, 173763. 

Discussion.-This species is only questionably assigned to Falsipollex because it apparently lacks the 

two ventral spurs on the tecnomorph which are considered diagnostic of the genus by Kesling and McMillan (1951, p. 67-68). However, the lobation, ornamentation and dolonate character of the heteromorphic velum are all more suggestive of Falsipollex 

than of any other hollinid genus. The specific name 

is derived from the abundant spines. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Family HOLLINELLIDAE Bless and Jordan, 1971 

Discussion.-Bless ::tnd Jordan (1971, p. 870-873, 

880-881) proposed the family Hollinellidae for hollinomorph ostracodes with velar and lobate dimorphism. They considered the "tecnomorphs" of hollinellid genera to be those with a wide frill and welldeveloped antrum and the "heteromorphs" to be 

those with a narrow frill and a canaliculus, because 

in genera such as Jordanites Bless, 1967 and Hollinella (Praehollinella) Bless and Jordan, 1971, juvenile specimens have a wide frill (Bless and Jordan, 

1971, p. 870-872). Later, Bless and Jordan (1972, 

p. 10-13) substituted the terms "presumable male" 

and "presumable female" for "tecnomorph" and 

"heteromorph," respectively. As originally proposed 

by Jaanusson and Martinsson (1956, p. 401-402), 

the term "tecnomorph" referred to juveniles of both 

sexes and the adult dimorph which resembled the 

juveniles; "heteromorph" referred to the adult dimorph which differed from the juveniles. Because 

there is no evidence that the adult male, rather than 

the female, did not develop dimorphism in the last 

molt, we are using the terms "tecnomorph" and 

"heteromorph" rather than "presumable male" and 

"presumable female." Although Bless and Jordan 

( 1971) considered the wide frilled forms with a 

relatively narrower L3 to be tecnomorphs in the 

Hollinellidae, the only hollinellid for which we have 

growth stages, Adelphobolbina aliquanta n. sp., has 

narrow frilled juveniles with a relatively wide L3. 

Pending further study of Early and Middle Devonian hollinellids, we are considering the tecnomorph 

to be the narrow frilled form in the following 

descriptions. 

Genus HOLLINELLA Coryell, 1928 

Hollinella ludvigseni n. sp. 

Plate 7, figures 1-3 

?Hollinella sp., Copeland in Ludvigsen, 1970, p. 426. 

Description.-Valves subelliptical, preplete; hinge 

line long and straight. L1 broad, low; L2 small, 

ovate, nearly joined to L1; L3 bulbous, hemispherical, projecting to or slightly above hinge line. S1 

short, shallow, indistinct; S2 deep, expanded ventrally below proximal parts of L2 and L3 ; a shallow 

groove present posterior to L3. Ventral lobe from 

L1-L2 to posterior part of valve. Surface ornamented with small, closely spaced papillae. Velar 

frill broad, papillose, extending from anterior cardinal angle to midposteroventral margin, with a 

posterior spinelike projection. Frill flat to slightly 

convex in tecnomorph, slightly concave in heteromorphic valves. Posteriorly, valves have marginal 

denticles. 

Mat erial.-Two specimens from the Prongs Creek 

Formation, one specimen from the McCann Hill 

Chert. 

Measurements.-A heteromorphic valve is 1.20 

mm long and 0. 75 mm high; a tecnomorphic valve is 

1.15 mm long and 0.70 mm high. 

Types.-Holotype, GSC 29462; para types, GSC 

29463, USNM 173764. 

Discussion.-This species differs from H ollinella 

antespinosa (Ulrich, 1891) and H. plauta Kesling 

and Tabor, 1953, in having L3 hemispherical, without a dorsal projection. From H. pumila Kesling, 

1953, and H. senticosa Kesling, 1953, it differs in 

having a much more pronounced frill in both dimorphs. 

Occurrence.-Ludvigsen collection V -3, Prongs 

Creek Formation, Solo Creek, Yukon Territory; 

USGS collection 6492-SD, McCann Hill Chert, 

Eagle (D-1) quadrangle, Alaska. 

Hollinella paucituberculata n. sp. 

Plate 7, figure's 6-8 

?Hollinella sp., Copeland in Ludvigsen, 1970, p. 426. 

Description.-Valves triangular-subelliptical, preplete; hinge long, straight. L1 broad, with dorsal 

cusp projecting above hinge line on left valve; L2 

elongate, joined ventrally to L1; L3 large, bulbous, 

hemispherical, projecting above hinge line. Sl short, 

shallow to threadlike; S2 deep, joined dorsally to S1, 

with smooth, shallow geniculate ventral extension 
SYSTEMATIC PALEONTOLOGY 19 

crossing ventral lobe to velar frill; an indistinct 

smooth groove along posterior edge of L3. Ventral 

lobe traversed by ventral extension of S2 and postL3 groove. Lobes ornamented with widely spaced 

tubercles which are especially sparse on posterior 

quarter of valves. Velar frill flat, broad in heteromorph, narrower in tecnomorph, extending from 

anterior cardinal angle to midposteroventral margin, 

with posterior spinelike projection. Valves with margin~} denticles posteriorly. 

M aterial.-More than 20 valves from the Prongs 

Creek Formation and the Michelle Formation. 

Measurements.-The average length of several 

specimens is 1.49 mm; the average height is 0.87 

mm. 

Types.-Holotype. GSC 29494; paratypes, GSC 

29495, 29496. 

Discussion.-The s1parsely tuberculate lobes, the 

very sparsely tuberculate posterior, and the anterior 

cusp on the left valve serve to distinguish this species from the other species of Hollinella which have 

a ventral extension of S2. H. paucituberculata differs from H. antespinosa (Ulrich, 1891) in having 

a more distinct ventral extension of S2, different 

surface ornamentation, and a differently shaped L3. 

It is more similar to H. sella Stover, 1956, but as 

illustrated by Stover (1956, pl. 111, figs. 1-6), H. 

sella has a more distinct L2 and a more bulbous L3 

than H. paucituberculata. Also, H. paucituberculata 

has a small, posteriorly directed spine at the posterior cardinal angle which may prove to be of specific 

importance. The presence of this spine, the anterodorsal cusp, and the pattern of the tubercles in this 

species are very similar to the same characters in 

Adelphobolbina aliquanta n. sp. 

Occurrence.-Ludvigsen collections 11-13, and 11-

14, from the Michelle Formation, Blackstone River, 

Yukon Territory, and Ludvigsen collection V-3, from 

the Prongs Creek Formation, Solo Creek, Yukon 

Territory. 

Genus ABORTIVELUM n. gen. 

Type species.-A bortivelum truncatum n. sp. 

Species included.-Only the type species. 

Diagnosis.-Hollinellid ostracodes with cuspate 

L1, distinct L2, L3 large and confluent with ventral 

lobe. Velum reduced to velar bend or ridge in tecnomorph, restricted to anterior and anteroventral part 

of valves in heteromorph. Heteromorphic velum not 

distinctly set off from domicili urn. 

Discussion.-The reduced and suppressed velum 

distinguishes this genus from other hollinellid 

genera. Abortivelum most closely resembles Flaccivelum Kesling and Tabor, 1952, by the lack of distinct separation between the heteromorphic velum 

and the domicili urn, but in Flaccivelum the velum 

extends posteriorly beyond S2 and ends in a sharp 

spur, whereas in Abortivelum the velum does not 

extend posteriorly beyond S2 and merges smoothly 

with the surface of the valve. The name of the genus 

is based on the suppressed character of the velum. 

Geologic range.-Lower Devonian of Alaska. 

Abortivelum truncatum n. sp. 

Plate 6, figures 10-16 

Description.-Lateral outline preplete. Hinge line 

straight; anterior margin rounded; ventral margin 

smoothly curved and merging with smoothly curved 

posterior margin. L1 cuspate on both valves; cusp 

projecting above hinge line in lateral view. L2 small, 

oblong, distinctly separated from L1 by very short 

but deep Sl. L3 large, bulbous, projecting above 

hinge line in lateral view; separated from posterior 

slope of valve by shallow posterodorsal depression 

but not clearly separated posteroventrally or ventrally. S2 deep, narrow, extending from dorsal margin to about midvalve. Tecnomorph with velar bend 

extending from anterior cardinal angle to posteroventral quarter of valve; heteromorph with velar 

frill extending from anterior cardinal angle to below 

S2. Velar frill merges with lateral surface of valve 

and is not distinctly separated from it. Surface finely 

granulose. 

Material.-Nineteen specimens, including one 

complete heteromorphic and three complete tecnomorphic carapaces, from the McCann Hill Chert. 

Measurements.-The holotype is 1.35 mm long 

and 0.85 mm high. 

Types.-Holotype, USNM 173752; paratypes, 

USNM 173751, 173753, 173754. 

Discussion.-This distinctive species does not 

closely resemble any previously described hollinellid. 

The specific name is derived from the truncated 

appearance of the heteromorph. 

Occurrence.-VSGS collection 7032-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus ADELPHOBOLBINA Stover, 1956 

Adelpbobolbina aliquanta n. sp. 

Plate 6, figures 17-22 

Adelphobolbina sp., Berdan in Churkin and Brabb, 1968, 

table 1, pl. 4, fig. 6. [Imprint 1967.]; Copeland in 

Ludvigsen, 1970, p. 426 (part). 

Description.-Carapace elongate, amplete. Dorsum straight; anterior margin narrowly rounded; 

ventral margin smoothly curved ; posterior margin 

denticulate, gently curved to acuminate posterior 

cardinal angle. L1 large, inflated, dorsally with tu-
20 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

bercle projecting above hinge line, which is most 

prominent on left valve, posteriorly with shallow depression (S1) marking junction with fused L2. S2 

deep, extending from dorsal border to mid valve, 

geniculate, concave anteriorly. L3 large, inflated, 

extending smoothly into ventral lobe, distinctly separated from posterodorsal field. Posterior surface of 

valve sloping gently to posterior margin. Cardinal 

angles distinct, anterior about 110°, posterior about 

90°; some specimens with posterior cardinal spine. 

Velar frill extending from anterior cardinal angle 

to posteroventral part of valve, terminating posteriorly in spine. Lateral surface with numerous tubercles on lobate areas; posterior surface with few 

tubercles. Smaller tubercles along dorsal margin and 

at outer edge of velar frill. Heteromorphic valves 

with wide straight velar frill; tecnomorphic frill 

narrower. 

M aterial.-More than 40 specimens from the McCann Hill Chert; 1 specimen from the Michelle 

Formation. 

Measurements.-The holotype is 1.55 mm long and 

0.90 mm high. A smaller tecnomorph is 1.50 mm long 

and 0.85 mm high. 

Types.-Holotype, USNM 173755; paratypes, 

USNM 170341, 173756, 173757, 173758, GSC 29497. 

Discussion.-This species is similar to Adelphobolbina papillosa (Ulrich, 1891) but is less tuberculate on the posterior slope, has a velar frill ending 

abruptly rather than smoothly as in A. papillosa, 

has an anterodorsal cusp on the left valve, and is 

more acuminate posteriorly. A. aliquanta differs 

from A. megalia (Kesling and Tabor, 1953) and A. 

pinguis (Kesling and McMillan, 1951) in being more 

coarsely tuberculate, but it is not coarsely spinose 

like A. spicata (Kesling and McMillan, 1951). A. 

medialis Stover, 1956 and A. trilobata (Stewart, 

1936) have a longer S2 than A. aliquanta. According 

to Warthin (1937, card 66), A. bulbosa (Tolmachoff, 

1926), from the Middle Devonian (bed Db) of Ellesmere Island, is evenly pustulose, except on the velar 

frill, and A. papillata (Tolmachoff, 1926) is pustulose on the lobes but not on the posterior slope (Warthin, 1937, card 67). The specific name aliquanta 

refers to the moderate number of tubercles. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen 

collection II-13 from the Michelle Formation, Blackstone River, Yukon Territory. 

Adelphobolbina prongsensis n. sp. 

Plate 7, figures 9-13 

Adelphobolbina sp., Copeland in Norris, 1967a, p. 138, 140; 

Copeland in Ludvigsen, 1970, p. 426 (part). 

Description.- Carapace elongate, subelliptical, 

slightly preplete in lateral view. Dorsum straight; 

anterior margin rounded ; ventral margin gently 

curved ; posterior margin rounded. S2 deep, extending from dorsal border to midvalve, slightly concave 

anteriorly and continued as shallow narrow constriction nearly to ventral frill. L1 large, inflated, with 

shallow depression posteriorly marking junction 

with fused L2. L3 large, inflated, slightly constricted 

at confluence with gently curved ventral lobe. Posterior surface of valve sloping gently to posterior 

margin. Cardinal angles obtuse, anterior about 120°, 

posterior about 100°. 

Velar frill extending from anterior cardinal angle 

to posteroventral part of valve, wider anteriorly. 

Lateral surface with papillae of two sizes; smaller 

papillae on lobes and larger ones on posterior part 

of valves and, on tecnomorphic valve, between velar 

frill and lobate areas. Heteromorphic valve with 

wide, straight velar frill almost in contact with 

ventral lobe; larger papillae restricted to posterior 

part of valve. 

M aterial.-Five specimens from the Prongs Creek 

Formation. 

Measurements.-The holotype is 1.45 mm long and 

0.93 mm high. A tecnomorphic valve, paratype GSC 

29501, is 1.45 mm long and 0.84 mm high. 

Types.-Holotype, GSC 29498; para types, GSC 

29499, 29500, 29501, 29502. 

Discussion.-This species is most similar to Adelphobolbina papillosa (Ulrich, 1891), from the Jeffersonville Limestone of Indiana and A. megalia (Kesling and Tabor, 1953) from the Genshaw Formation 

of Michigan. A. papillosa, however, has more and 

larger papillae and, on the heteromorph, a more discrete, prominent velar frill (Kesling and Tabor, 

1953, pl. 3, figs. 16, 17) ; A. megalia has a broader 

L3, more discrete velar frill, and apparently lacks 

the faint ventral constriction at the base of S2 which 

slightly separates L1 from the ventral lobe. This 

ventral constriction or prolongation of S2 is not as 

well developed as that in A. medialis Stover, 1956, 

where it is a definite part of S2. A. medialis, unlike 

A. prongsensis, is evenly papillose. 

Occurrence.-Ludvigsen collections V -3, V -4, 

from the Prongs Creek Formation, Solo Creek, Yukon Territory. 

Adelphobolbina sp. cf. A. medialis Stover, 1956 

Plate 7, figures 4, 5 

Adelphobolbina medialis Stover, 1956, p. 1104-1105, pl. 112, 

figs. 4-9. 

Description.-Lateral outline amplete; dorsum 

straight; anterior and posterior margins evenly 

rounded; ventral margin smoothly curved. L1 large, 
SYSTEMATIC PALEONTOLOGY 21 

low, separated from small oval L2 by short, shallow, 

indistinct Sl. S2 wide, deep, extending more than 

half height of valve and continued ventrally to margin of domicilium by shallow depression. L3 large, 

inflated, merging with ventral lobe but distinctly 

separated from relatively narrow posterodorsal field. 

Cardinal angles obtuse. Velar frill extending from 

anterior cardinal angle to posterior edge of L3. Surface of domicilium evenly papillose except for deep 

parts of S2. A few scattered papillae present on 

velar frill. 

Material.-Twenty valves from the McCann Hill 

Chert. 

Measurements.-The two figured specimens are 

1.25 mm long and 0. 77 mm high and 1.25 mm long 

and 0.75 mm high, respectively. 

Types.-Figured specimens, USNM 173759, 

173760. 

Discussion.-The specimens from the McCann Hill 

Chert all appear to be immature tecnomorphs. They 

resemble Adelphobolbina medialis Stover, 1956, in 

having S2 long and extending in a shallow furrow 

to the velar frill, in the evenly papillose surface and 

in the inflated L3. However, in typical A. medialis, 

L2 is completely merged with L1, and S1 is entirely 

suppressed. Also, A. medialis appears to lack papillae on the velar frill. A. medialis is from the Windom 

Member of the Moscow Shale (Middle Devonian) of 

western New York, and until definite adult specimens from the Lower Devonian of Alaska can be 

found it seems better to compare the McCann Hill 

Chert specimens with A. medialis rather than assigning them to the species. 

Occurrence.-USGS collections 6492-SD, 7033-

SD, 7037-SD, 7038-SD, from the McCann Hill Chert, 

Eagle (D-1) quadrangle, Alaska. 

Genus FLACCIVELUM Kesling and Peterson, 1958 

Flaccivelum sp. 

Plate 8, figures 15, 16 

Description.-Valve elongate, amplete. L2 somewhat elongate, partly fused with L1; dorsal edge of 

L1 extending to hinge line. S2 deep, curved anteriorly, extending from hinge line to near midvalve. L3 

broad, extending slightly above hinge line. L1 and 

L3 confluent with ventral lobe. Posterior part of 

valve gently convex, not lobate. Heteromorph with 

broad flat frill, confluent with lateral surface and 

deflected laterally at its posterior end. 

M aterial.-One heteromorphic right valve from 

the Michelle Formation. 

Measurements.-The figured specimen is 1.10 mm 

long and 0.70 mm high. 

Types.-Figured specimen, GSC 29509. 

Discussion.-This specimen is most nearly similar 

to Flaccivelum teleutaea (Kesling and Tabor, 1952) 

and F. informis (Ulrich, 1891), but differs from both 

in lacking a posteroventral projection of the ventral 

lobe and in having L3 confluent with the ventral lobe. 

Occurrence.-Ludvigsen collection II-10, Michelle 

Formation, Blackstone River, Yukon Territory. 

Genus INFRACTIVELUM n. gen. 

Type species.-lnfractivelum acuminatum n. sp. 

Species included.-lnf1·activelum spiculosum n. sp. 

Diagnosis.-Hollinellid ostracodes with· distinct 

L2 and prominent L3 continuous with ventral lobe. 

Velum continuous from anterior cardinal angle to 

midposteroventral slope in both tecnomorphs and 

heteromorphs. Heteromorphic velum only weakly 

separated from lateral surface of domicilium. Tecnomorphic velum of same extent as heteromorphic 

velum but narrow and flaring away from free margin. L1 may extend as cusp above hinge line ol1 left 

valve of adult tecnomorph. 

Discussion.-The lobation of lnfractivelum differs 

from that of H ollinella Coryell, .1928, in having L3 

confluent with the ventral lobe rather than bulbous, 

and from that of Adelphobolbina Stover, 1956, in 

having L3 narrower and more prominent. lnf'ractivelum resembles Ruptivelum Kesling and Weiss, 

1953, in having a relatively distinct L2, but differs 

from that genus in having an uninterrupted tecnomorphic velum even in immature specimens (pl. 8, 

fig. 20). The heteromorphic velum of lnfractivelum 

is like that of Flaccivelum Kesling and Tabor, 1952, 

but lacks the outward posterior swing of that genus, 

and the lobation of lnfractivelum is more distinct. 

Jordanites Bless, 1967, and Hollinella (Praehollinella) Bless and Jordan, 1971, both have the velum 

merging gradually with the domicilium at its posterior end rather than truncated as in lnfractivelum. 

The name is based on the unbroken character of the 

velum. 

Geologic range.-Lower Devonian of Alaska and 

Yukon Territory. 

lnfractivelum acuminatum n. sp. 

Plate 8, figures 19-23 

Adelphobolbina sp., Copeland in Ludvigsen, 1970, p. 426 

(part). 

Description.- Carapace elongate, subelliptical, 

preplete, somewhat acuminate posteriorly. Dorsum 

long, straight; lateral borders subround; free margins gently curved. S2 deep, slitlike, extending from 

dorsal margin to midvalve, slightly concave anteriorly. L1 large, inflated, with short dorsal cusp extending above hinge line of left valve. L2 fused to L1 

ventrally but separated dorsally by short Sl. L3 

large, inflated, somewhat angular dorsally and extending to or beyond hinge line. Posterior surface of 
22 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

valve sloping gently to posterior margin. Anterior 

cardinal angle broad, about 110°; posterior cardinal 

angle narrow, nearly 90°. Velar frill extending from 

anterior corner to posteroventral part of valve, narrow in tecnomorphs. Heteromorphic valves with 

wider frill confluent with L1 and ventral lobe. Lateral surface with uniform fine papillae. 

Material.-Five specimens from the Prongs Creek 

Formation. 

Measurements.-The holotype is 1.60 mm long and 

1.00 mm high. A tecnomorphic left valve is 1.30 mm 

long and 0.75 mm high. 

Types.-Holotype, GSC 29503; para types, GSC 

29504, 29505, 29506, 29507. 

Discussion.-Small specimens which are considered to be immature tecnomorphs of this species do 

not have as acuminate an L3 as the adults. 

Occurrence.-Ludvigsen collections V -3 and V -4, 

from the Prongs Creek Formation, Solo Creek, Yukon Territory. 

lnfractivelum spiculosum n. sp. 

Plate 8, figures 24-27 

Hollinella? sp., Berdan in Churkin and Brabb, 1968, table 

1, pl. 4, fig. 7. [Imprint 1967.] 

Description.-Lateral outline preplete; dorsal 

margin straight; anterior margin smoothly curved ; 

ventral margin less sharply curved ; posterior margin curved up to sharp posterior cardinal angle, 

which is about 90°. Anterior cardinal angle rounded. 

L1 with anterodorsal cusp which projects over hinge 

line on both valves; L2 small, ovate, separated from 

L1 by short shallow S1; L3 bulbous, acuminate, with 

point directed perpendicular to lateral surface. S2 

wide, deep to about midheight of valve, curved anteriorly beneath L2 and extended as shallow groove 

around anterior end of ventral lobe to velar frill. 

Posterior part of valve slopes smoothly to posterior 

margin. Surface finely granulose with scattered large 

papillae on the lobate areas, especially prominent on 

L3 and parallel to velar frill. Velar frill extends from 

anterior cardinal angle to posteroventral part of 

valves; wide, confluent with lateral surface, and 

curved toward contact margin in heteromorph ; narrower and reflexed away from contact margin in 

tecnomorph. 

M aterial.-Six specimens from the McCann Hill 

Chert. 

Measurements.-The holotype is 1.55 mm long and 

0.92 mm high. A tecnomorphic paratype is 1.30 mm 

long and 0. 77 mm high. 

Types.-Holotype, USNM 107342; para types, 

USNM 173765, 173766, 173767, 173768. 

Discussion. - lnfractivelum spiculosum differs 

from I. acuminatum in having a more acuminate L3, 

distinct anterodorsal cusps on both valves and larger, 

and less regularly distributed papillae. The specific 

name refers to the sharp, anterodorsal cusps. 

Occurrence. - USGS collections 6492-SD and 

7033-SD, from the McCann Hill Chert, Eagle (D-1) 

quadrangle, Alaska. 

Superfamily KIRKBYACEA Ulrich and Bassler, 1906 

Family ARCYZONIDAE Kesling, 1961 

Genus CHIRONIPTRUM Kesling, 1952 

Chironiptrum reticularis n. sp. 

Plate 8, figures 9-14 

Chironiptrum sp., Copeland in Ludvigsen, 1970, p. 426, 427 

(part). 

Description.-Valves subelliptical, slightly postplete; right larger than left. Hinge line straight; 

free margins evenly curved. Deep pit near center of 

valve. Lateral surface surrounded by wide flaring 

frill confluent with dorsal ridge. Greatest height and 

width posterior. Lateral surface strongly reticulate; 

frill and channel smooth. Marginal ridge on both 

valves; ridge on right valve larger, somewhat tuberculate. Thin ridge at contact margin of right valve 

for closure against marginal ridge of left valve. 

Marginal ridge extending posteriorly beyond frill in 

some specimens. 

M aterial.-Six specimens from the Michelle Formation. 

M easurements.-Average of several specimens, 

length, 0.80 mm, height, 0.50-0.55 mm. 

Types.-Holotype, GSC 29456; paratypes, GSC 

29457, 29458, 29459, 29460, 29461. 

Discussion.-This species is typical of the genus, 

but differs from Chironiptrum oiostathmicum Kesling, 1952, the type species, in being more coarsely 

reticulate, in lacking papillae at the intersections of 

the reticulae, and in lacking spurlike projections at 

the cardinal angles. 

Occurrence.-Ludvigsen collections. II-10 and II13 from the Michelle Formation, Blackstone Creek, 

Yukon Territory. 

Chironiptrum limitaris n. sp. 

Plate 8. figures 2-8 

Chironiptrum sp., Berdan in Ghurkin and Brabb, 1968, table 

1, pl. 4, fig. 2. [Imprint 1967.]; Copeland in Ludvigsen, 

1970, p. 426, 427 (part). 

Description.-Valves subelliptical, slightly postplete; hinge line straight; anterior and posterior 

margins evenly curved ; ventral margin gently curved 

to nearly straight. Deep drop-shaped pit slightly anterior of center of valve. Lateral surface surrounded 

by wide flaring frill confluent with dorsal ridge, 

which is only faintly visible along dorsal margin in 

lateral view. Lateral surface finely reticulate, some 

papillae at junctions of ridges forming reticulation. 
SYSTEMATIC PALEONTOLOGY 23 

Frill and channel smooth. Marginal ridge around 

free margin. 

Material.-More than 60 specimens from the McCann Hill Chert, 1 specimen from the Prongs Creek 

Formation. 

Measurements.-The holotype is 0.80 mm long, 

0.50 mm high, and 0.40 mm wide. Measurements of 

53 other specimens are shown in figure 6. 

Types.-Holotypes, USNM 173770; paratypes, 

GSC 29455, USNM 170337, 173769, 173771, 173772, 

173773. 

Discussion.-This species is most similar to Chironiptrum oiostathmicum Kesling, 1952, in shape, 

size of reticulation, and presence of papillae on the 

lateral surface, but the reduction of the frill along 

the dorsal margin in C. limitaris distinguishes it 

from that species. C. limitaris differs from C. reticularis n. sp. in the presence of papillae on the lateral 

surface of the valve and in being more finely reticulate. 

This species is fairly abundant in collection from 

the McCann Hill Chert, but only one collection, 

USGS collection 7037-SD, contains many immature 

specimens ; the other collections contain mostly 

adults. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, 7038-SD, all from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; 

Ludvigsen collection V -3, Prongs Creek Formation, 

Solo Creek, Yukon Territory. 

Genus OBOTRITIA Adamczak, 1968 

Obotritia? sp. 

Plate 8, figure 1 

Description.-Lateral outline amplete to slightly 

preplete; hinge line straight; free margins evenly 

rounded. Subelliptical high carina approximately 

concentric about obscure muscle spot but eccentric 

to margins of valve; low dorsally, slightly sinuate 

anterodorsally, high and flaring anteroventrally, 

ventrally, and posteriorly. Posterior quarter of valve 

extends beyond carina. Anterior cardinal angle produced as anterodorsal spine; posterior cardinal 

angle broken. Lateral surface enclosed by carina 

very finely punctate; surface outside carina smooth. 

M aterial.-One left valve from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0. 70 mm 

long and 0.47 mm high. 

Types.-Figured specimen, USNM 17377 4. 

Discussion.-This single specimen is questionably 

assigned to Obotritia Adamczak, 1968, because it has 

a muscle spot rather than a central pit and an elliptical carina which is confluent with the dorsal ridge. 

However, Obotritia eifeliensis Adamczak, 1968, as 

described and illustrated by Adamczak (1968, p. 85-

0.5~----~------.-----,,,-----,,------r-,----,,------Tj----~~r-.----~~----~ 

-

EXPLANATION 

2 3 4 5 6 

Number of specimens with 

identical measurements 

I I 

• 

• •• • 

• 

I I 

• •• 

• • • • 

• • 

• 

I 

0.5 

•• 

• 

I 

MAXIMUM LENGTH, IN MILLIMETERS 

I 

• • 

I I 

-

-

-

-

1.0 

FIGURE 6.-Scatter diagram of maximum length versus maximum height for Chironiptrum limitaris n. sp.; 53 specimens from the McCann Hill Chert (USGS colln. 7037-SD, paratype slide USNM 173772). 
24 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

86, pl. 38, figs. 1-3) is coarsely reticulated and the 

carina is parallel to the free margins. 

Occurrence.-USGS collection 7037-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Family KIRKBYELLIDAE Sohn, 1961 

Genus KIRKBYELLA Coryell and Booth, 1933 

Subgenus KIRKBYELLA Coryell and Booth, 1933 

Kirkbyella (Kirkbyella) sp. 

Plate 9, figure 1 

Description.-Lateral outline amplete; anterior 

and posterior margins smoothly curved ; ventral 

margin straight. Essentially unisulcate; 81 obsolete, 

S2 narrow, deep, extending from hinge line to onehalf or one-third height of valve and curving dorsally and ventrally to outline small rounded L2. V entral lobe large, massive, projecting as sharp spine 

posteriorly, separated from ventral margin by narrow rim. Cardinal angles obtuse. Valve covered with 

very fine striations approximately parallel to margins. 

Material.-Three valves from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0.60 mm 

long and 0.30 mm high. 

Types.-Figured specimen, USNM 173775. 

Discussion.-These specimens have the narrow 

rim beneath the posterior part of the ventral lobe 

characteristic of Kirkbyella (Kirkbyella) as described by Sohn (1961, p. 143) and are consequently 

assigned to that subgenus. The specimens are not 

sufficiently complete to justify giving them a formal 

name, but the distinctive striated ornamentation is 

unlike that of any other described species of Kirkbyella. 

Occurrence.-USGS collection 7037 -SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Suborder NODELLOCOPINA Becker, 1968 

Superfamily NODELLACEA Becker, 1968 

Family NODELLIDAE Zaspelova, 1952 

Genus HANAITES Pokorny, 1950 

Type species.-Halliella (Hanaites) givetiana Pokorny, 1950. 

Species included.-P1·oplectrum platum Kesling 

and McMillan, 1951. 

?Eurychilina mirabilis Polenova, 1952. 

H ana'ites linearis n. sp. 

H anaites brevis n. sp. 

H anaites spinosus n. sp. 

Revised diagnosis.-Unisulcate paleocope ostracodes, preplete to amplete in lateral outline. Sulcus 

vertical or slanted posteriorly. Velum developed anteriorly as palmate or hooklike projection (hamus) 

in tecnomorph; heteromorph with velum widened 

and bent away from free margin anteriorly. Lateral 

surface reticulate or punctate; velum and sulcus 

smooth. 

Discussion.-Hanaites, originally considered a 

subgenus of Halliella by Pokorny (1950, p. 599), was 

placed in the Hollinidae by Stover (1956, p. 1105) 

because the velar dimorphism of the heteromorphs 

which he had found suggested a relationship with 

the hollinids. Recently Becker (1968a, p. 129-131; 

1968b, p. 553-555) proposed the suborder N odellocopina and the superfamily Nodellacea to include the 

family N odellidae Zaspelova, 1952, with two genera, 

Nodella Zaspelova, 1952, and Tetracm·nella Zaspelova, 1952, which have hamal dimorphism, that is, 

velar dimorphism in which the tecnomorphic velum 

forms a projection or hook (hamus) anteriorly and 

the heteromorphic velum widens and flares away 

from the contact margin anteriorly. This type of 

dimorphism is also characteristic of H anaites, which 

accordingly is here assigned to the family N odellidae. 

Geologic range.-Lower Devonian of Alaska and 

Yukon Territory; Middle Devonian of the eastcentral United States, Czechoslovakia, and possibly 

the U.S.S.R. 

Hanaites linearis n. sp. 

Plate' 9, figures 2, 3 

Description.-Carapace elongate; lateral outline 

preplete. Hinge line straight; anterior border 

evenly curved ; ventral border straight to convex, 

inclined ; posterior border more acutely convex, 

somewhat acuminate. Anterior cardinal angle about 

100°; posterior cardinal angle 75° to 80°. Sulcation 

consisting of S2, which slants slightly posteriorly 

from dorsal margin to slightly below midvalve. S2 

widens and deepens ventrally, ending in rounded pit, 

and is bounded, except dorsally, by smooth rim. Lobation consisting of confluent L1 and L2, ventral 

lobe and L3. 

Velar frill continuous from posterodorsal corner 

to midanterior margin, in heteromorph becoming 

broader anteriorly, in tecnomorph of equal width 

throughout and terminating anteriorly in a spurlike 

process (ham us). Smooth antrum between velar frill 

and fine marginal ridge. Marginal ridge projects 

slightly beyond velar frill posteroventrally. 

Surface of valves deeply reticulate, except for 82 

and anterodorsal corner, with row of reticulae at 

dorsal contact of velar frill and domicilium. Dorsal 

crest limits reticulae dorsally, extending as fine ridge 

from near anterior end of velar frill, above L1-L2, 

forming part of rim around S2, projecting across L3 

as a straight ridge posteriorly from the postero-
SYSTEMATIC PALEONTOLOGY 25 

dorsal corner of 82 and ending in a downcurved, 

more broadly projecting angulation. 

Material.-Four specimens from the Prongs Creek 

Formation. 

Measurements.-The holotype is 1.38 mm long and 

0.65 mm high. 

Types.-Holotype, GSC 29478; paratype, GSC 

29477. 

Discussion.-This species differs from H anaites 

givetiana Pokorny, 1950, the type species of the 

genus, in the development of a dorsal crest and in 

having 82 inclined posteriorly rather than vertical 

(Pokorny, 1950, p. 600.) H. platus (Kesling and McMillan, 1951) lacks the dorsal crest of H. linearis, 

has a more pronounced palmate anterior spur and a 

posterodorsal node. Eurychilina mirabilis Polenova, 

1952, appears to be referable to H anaites, but the 

illustrations of this species (Polenova, 1952, pl. 1, 

fig. 5; Rozhdestvenskaya, 1962, pl. 6, figs. 1, 2) indicate that it has a spine at the posterior cardinal 

angle and that its S2 is more vertical than that of 

H. linearis. Differences between H. linearis and the 

two new species, H. brevis and H. spinosus, are discussed under those species. The specific name of H. 

linearis is based on the linear character of the dorsal 

crest. 

Occurrence.-Ludvigsen collections V -3, V -4, and 

V -5 from the Prongs Creek Formation, Solo Creek, 

Yukon Territory. 

Hanaites brevis n. sp. 

Plate 9, figure-s 4-9 

Hanaites sp. B, Berdan in Churkin and Brabb, 1968, table 

1, pl. 4, fig. 5. [Imprint 1967.] 

Description.-Carapace short for genus; lateral 

outline slightly preplete. Hinge line straight; anterior border evenly curved ; ventral border gently 

convex, inclined posteriorly; posterior border more 

sharply convex. Anterior cardinal angle more than 

130°; posterior cardinal angle 90° to 115°. S2 slants 

slightly posteriorly to midvalve or slightly below, 

widens and deepens ventrally, ending in rounded pit, 

and is bordered by narrow, smooth rim. 

Velar frill narrow, reduced anterodorsally; in tecnomorph produced as small, thin, ventrally directed 

hooklike spur (hamus) at midheight of valves on 

anterior margin ; in heteromorph wider anteroventrally and deflected away from free margin at about 

midheight, spur lacking. Antrum between velar frill 

and marginal ridge reticulate in both heteromorph 

and tecnomorph. Marginal ridge widens posteroventrally, projects from beneath velar frill posteriorly, and is deflected away from contact margin on 

each valve posterodorsally so that a small oval chamber, open posteriorly, is formed on the posterodorsal 

end of both tecnomorphic and heteromorphic carapaces. 

Surface of valves deeply reticulate except for anterodorsal corner, S2, and velar frill. Row of larger 

reticulae at dorsal contact of velar frill and domicilium. Four to six reticulae between ventral end of 

S2 and velar frill. Narrow dorsal crest extends from 

posterodorsal end of S2 posteriorly and bends ventrally before reaching posterior cardinal angle. Posterior end of dorsal crest raised as low knob on som.e 

specimens. Narrow groove on each valve between 

dorsal crest and hinge line (pl. 9, fig. 8). 

Material.-More than 110 specimens from the McCann Hill Chert. 

Measurements.-The holotype is 1.33 mm long and 

0.75 mm high. A figured paratype (USNM·173776) 

is 1.35 mm long and 0. 70 mm high. The length and 

height of 54 specimens, including the holotype, are 

shown in figure 7. 

Types.-Holotype, USNM 173777; paratypes, 

17034~ 17377~ 173777a, 17377~ 173779. 

Discussion.-H anaites brevis differs from other 

species assigned to Hanaites in being relatively short 

and stout and in having a weak, poorly developed 

hamus. It most closely resembles H. linearis n. sp. in 

having a linear dorsal crest on each valve, but H. 

linearis is more elongate, the dorsal crest is better 

developed, and there are three to four reticulae between S2 and the velar frill rather than four to six 

as in H. brevis. Also, the heteromorphic velar frill is 

wider in H. linearis than in H. b1·evis. The specific 

name of H. brevis refers to its short lateral outline. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, and 7038-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Hanaites spinosus n. sp. 

Plate 9, figures 10-15 

Hancdtes sp. A, Berdan in Churkin and Brabb, 1968, table 

1, pl. 4, fig. 4. [Imprint 1967.]; Copeland in Ludvigs.en, 

1970, P• 426. 

Description.-Carapace elongate; lateral outline 

preplete. Dorsal border straight; anterior border 

broadly rounded; ventral border straight, inclined; 

posterior border narrowly rounded. Anterior cardinal angle about 110°, posterior cardinal angle about 

90°. Sulcation consisting of S2, which slants slightly 

posteriorly to midvalve, terminating in deep rounded 

pit. Lobation consisting of combined L1 and L2, 

ventral lobe, and L3, all confluent. 

Velar frill continuous from somewhat above midheight on anterior margin to posterodorsal cardinal 

angle; widest on anterior half of valve; projecting 

ventrally as hooklike spur in tecnomorphs, wider and 

bent away from free margin anteriorly in hetero-
26 OSTRACODES. FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

1.0~---------------------~,---------------------.,------~--------------· 

(/) 

a: 

w 

1-

w 

:E 

...J 

...J 

:E 

~ 

.... - 0.5-

I 

(!) 

w 

I 

:E 

:I 

:E 

X 

<( 

:E 

0 

EXPLANATION 

2 3 4 

Number of specimens with 

identical measurements 

I 

0.5 

• (j) (j) 

-. 

I 

1.0 

. •· 

• ' .. ••• 

• • • • ·•@•- - . . ... --

.. :·:r· ::. . - ... - .... 

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1.5 

MAXIMUM WIDTH, IN MILLIMETERS 

FIGURE 7.-Scatter diagram of maximum length versus maximum height for Hanaites brevis n. sp.; 54 specimens from the McCann Hill Chert (USGS colln. 6492-SD, paratype slide 173779). 

morphs. Smooth antrum between velar frill and fine 

marginal ridge, which projects posteriorly beyond 

velar frill. Dorsal ridge on left valve overreaches 

dorsal margin of right valve. Surface of valves, except for S2 and anterodorsal corner, deeply reticulate, with row of larger pitlike reticulae at dorsal 

proximal edge of velar frill. Anterodorsal corner 

more finely reticulate and with tendency to develop 

oblique ridge parallel to anterodorsal free margin. 

Large, blunt, posterodorsally inclined reticulate 

spine on L3 in posterodorsal part of valve below 

hinge line. 

Material.-Twenty-four specimens from the McCann Hill Chert and two specimens from the Michelle Formation. 

Measurements.-The holotype (USNM 173780) is 

1.30 mm long and 0.75 mm high. An immature tecnomorph (USNM 173781) from the McCann Hill 

Chert is 1.00 mm long and 0.50 mm high. An immature tecnomorph from the Michelle Formation is 

0. 70 mm long and 0.40 mm high ; a mature specimen 

(GSC 29479) from the Michelle Formation is 1.05 

mm long and 0.60 mm high. 

Types.-Holotype, USNM 173780; paratypes, 

USNM 170339, 173781, 173782, 173783, GSC 29479, 

29479a. 

Discussion.-Hanaites spinosus has a much more 

pronounced posterodorsal spine than H. platus (Kesling and McMillan, 1951) and is less elongate than 

that species. The other described species of H anaites 

apparently lack the prominent posterodorsal spine. 

H. linearis n. sp. and H. brevis n. sp. may develop a 

low node at the posterodorsal angulation of the dorsal crest, especially in immature tecnomorphs, but 

this node is not- as large as the spine of H. spinosus, 

nor does H. spinosus have the dorsal crest of these 

species. The spines of H. spinosus are better developed on the left valves of adults than they are on the 

right, and the presence or absence of the anterodorsal ridge appears to be variable within the species. 

Some specimens are nearly smooth; this may be 

caused by differences in preservation or may be a 

variation ·Within· the-species. There is also variation 

in the degree of development of the ventral lobe, 

which is prominent in some specimens, especially 

small tecnomorphs. Furthermore, the posterodorsal 

spine is more prominent in young individuals. 

Occurrence.-'-USGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, 7038-SD, from the McCann 

Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection 11-10, from the Michelle Formation, 

Blackstone River, Yukon Territory. 
SYSTEMATIC PALEONTOLOGY 27 

Superfamily OEPIKELLACEA Jaanusson, 1957 

Family APARCHITIDAE Jones, 1901 

Genus SUBARCTICHITES n. gen. 

Type species.-Subarctichites ser1·atulus n. sp. 

Species included.-Aparchites crossotus Kesling, 

1952. 

Diagnosis.-Long hinged aparchitid ostracodes 

with distinct cardinal angles; free margin with row 

of denticles on anterior and venter but not on posterior. Velar bend smooth or denticulate. Hinge incised, of ridge and groove type. No dimorphism 

observed. 

Discussion.-This genus probably includes numerous aparchitids described from the Devonian which 

have denticulate margins, but the presence or absence of marginal denticles is not mentioned in 

many descriptions. Subarctichites differs from Aparchites s.s. as discussed by Swartz (1969, p. 1239) in 

the character of the free margin. The anterior position of the denticles on the free margin distinguish 

Subarctichites from the nonsulcate and nonspinose 

species assigned to the dimorphic genus Gravia Polenova, 1953, in which the denticles are posterior or 

posteroventral. The lack of cruminal dimorphism in 

Subarctichites separates it from the superficially 

similar genera Saccarchites Swartz and Whitmore, 

1956, and Phlyctiscapha Kesling, 1953. The name of 

the genus is based on its occurrence near, but south 

of, the Arctic Circle. 

Geologic range.-Lower Devonian of Alaska and 

Yukon Territory, Middle Devonian of Michigan. 

Subarctichites serratulus n. sp. 

Plate 9, figures 16-24 

Saccarchites? sp., Berdan in Churkin and Brabb, 1968, table 

1, pl. 4, fig. 15. [Imprint 1967.] 

Sacc.archites sp., Copeland in Ludvigsen, 1970, p. 426. 

Description.-Valves subovate, amplete to slightly 

preplete in lateral outline. Dorsal border of left 

valve nearly straight; dorsal border of righ~ valve 

slightly arched. Free margins evenly rounded. Greatest height and length nearly median; greatest thickness slightly posteromedian. Cardinal angles nearly 

equal, about 120°. Margin of valves with row of 

stout discrete spines extending from above midanterior margin to posteroventral part of valve; spines 

larger and more distant from contact margin on 

right valve. Supramarginal bend of same extent, 

parallel to and separated from marginal spines. 

Surface smooth or finely granulose. Hinge of right 

valve grooved; ends of hinge of left valve with 

notches at cardinal angles. Muscle scar is dark, 

round spot in central part of valve. 

Material.-Thirty-six specimens from the McCann 

Hill Chert; six specimens from the Prongs Creek 

Formation. 

Measurements.-The holotype is 1.20 mm long, 

0.87 mm high, and 0.87 mm wide. The measurements 

of six specimens from the Prongs Creek Formation 

are as follows (in millimeters) : length, 1.05, height, 

0. 70; length, 1.40, height, 1.00; length, 1.20, height, 

0.85; length, 1.40, height, 1.00; length, 1.32, height, 

1.05; length, 1.35, height, 1.00. 

Types.-Holotype, USNM 173784; paratypes, 

USNM 170350, 173785, 173786, 173787, 173788, GSC 

29483,29484,29485,29486. 

Discussion.-This species is very similar to Subarctichites crossotus (Kesling, 1952), from the Bell 

Shale of Michigan, in shape and presence of a marginal row of spines. S. serratulus, however, has a 

more elevated right dorsal margin and a marginal 

row of spines and a supramarginal bend instead of 

two rows of marginal spines like S. crossotus. Both 

species apparently have approximately the same dimensions, although the holotype of S. crossotus 

(Kesling, 1952, p. 24) is somewhat smaller than 

most of the specimens of S. serratulus. The cardinal 

sockets on the inside of the left valve appear to be 

for the reception of the cardinal angles of the right 

valve; no teeth or other projections have been observed in the right valve which would fit these 

sockets. The specific name of S. serratulus refers to 

the marginal denticles. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, all from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen 

collections V -3, V -4, from the Prongs Creek Formation, Solo Creek, Yukon Territory. 

Genus LIBUMELLA Rozbdestvenskaya, 1959 

Libumella sp. cf. L. discoides Rozbdestvenskaya, 1959 

Plate 10, figures 1-5 

Libumella -discoides Rozhdes.tvenskaya, 1959, p. 134, pl. 4, 

figs. 1a, b. 

Libumella sp., Copeland in Norris, 1967a, p. 115, 127, 138, 

140; Berdan in Ghurkin and Brabb, 1968, table 1, pL 

4, fig. 9. [Imprint 1967.]; Copeland in Ludvigsen, 1970, 

p. 426. 

Description.-Carapace large, subcircular in outline; length greater than height; anterior mar~in 

lower than posterior. Hinge short, incised, at midvalve. Left valve larger than right, overlapping right 

along entire free margin; left valve overr"""aching 

right at hinge line. Each valve with thin marginal 

ridge. Valve surface ornamented with deep punctae 

except marginally and in area of circular adductor 

scar. 

Material.-More than 80 specimens from the McCann Hill Chert; more than 60 specimens from the 

Prongs Creek Fo· "nation. 

Measurements. - Several specimens from the 

Prongs Creek Formation -range from 0.95 to 1.45 
28 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

mm in length and from 0.80 to 1.20 mm in height; 

the length/height ratio is 1.2. 

Types. - Figured specimens, USNM 170344, 

173789 ; GSC 29480, 29481. 

Discussion.-These specimens may be conspecific 

with those described and drawn by Rozhdestvenskaya (1959, p. 134, pl. 4, figs. 1a, b) from the Biya 

beds (Eifelian) of Bashkiria. The punctae of the 

Russian specimens may be slightly larger than those 

of the North American specimens. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7033-SD, 7038-SD, from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen 

collections V -3, V -4, V -5 from the Prongs Creek 

Formation, Solo Creek, Yukon Territory. 

Libumella sp. cf. L. circulata Rozhdestvenskaya, 1962 

Plate 10, figures 6-8 

Libumella circulata Rozhdestvenskaya, 196·2, p. 179, pl. 3, 

figs. 3a-g. 

Description.-Lateral outline subcircular to elliptical; dorsum rounded ; free margins evenly curved. 

Narrow, subdued rim around free margins of overlapping valve continued as weak margin parallel to 

dorsum; overlapped valve without rim. Shell surface 

smooth. Hinge short, straight, apparently slightly 

incised. 

M aterial.-One specimen from the McCann Hill 

Chert; five specimens from the Prongs Creek Formation. 

Measurements.-The figured specimen from the 

McCann Hill Chert is 1. 70 mm long and 1.35 mm 

high. 

Types.-Figured specimens, USNM 173790, GSC 

29482. 

Discussion.-These specimens differ from Libumella circulata as illustrated by Rozhdestvenskaya 

(1962, pl. 3, figs. 3a, b) in having the rim parallel 

to the dorsum less well developed, and in the specimen from the McCann Hill Chert having a better 

developed rim around the free margins. Otherwise 

they appear close to figures of typical L. circulata. 

Occurrence.-VSGS collection 7032-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collections V -3, V -4, V -5, from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Suborder KLOEDENELLICOPINA Scott, 1961 

Superfamily PARAPARCHITACEA Scott, 1959 

Family PARAPARCHITIDAE Scott, 1959 

Genus NEOAP ARCHITES Bout'ek, 1936 

Neoaparchites? sp. aff. N.? insericus (Rozhdestvenskaya, 1962) 

Plate 10, figures 9-12 

Punctaparchites insericus Rozhdestvenskay.a, 1962, p. 174, 

pl. 1, figs. 5a-g. 

Description.-Lateral outline suboval, preplete. 

Dorsum very slightly curved ; anterior and posterior 

ends evenly curved ; ventral margin broadly curved. 

Hinge straight, slightly incised. Left valve overlaps 

right very slightly; interior of left valve channelled 

along free margin to receive edge of right. Surface 

punctate except for postcentral smooth, poorly defined muscle spot and narrow area concentric to 

free margins. Punctae coarser around muscle spot, 

becoming finer toward free margins. 

M aterial.-One complete carapace and one right 

valve from the McCann Hill Chert. 

Measurements.-The complete carapace is 1.70 

mm long, 1.25 mm high, and 0.85 mm wide. 

Types. - Figured specimens, USNM 173791, 

173792. 

Discussion.-The specimens from the McCann Hill 

Chert differ from N eoaparchites? insericus from the 

Eifelian of the southern Urals as illustrated by 

Rozhdestvenskaya (1962, pl. 1, figs. 5a, g) in having 

a smooth muscle spot and in having a gradation 

from the center to the margins in the size of the 

punctae. N. ? insericus has been removed from Punctaparchites Kay, 1934, to which it was originally 

assigned by Rozhdestvenskaya, because Harris 

(1957, p. 261-263) has demonstrated that the type 

species of Punctaparchites, P. rugosus (Jones, 1858) 

was incorrectly oriented and is a podocopid. However, N.? insericus is only questionably assigned to 

N eoaparchites Boucek, 1936, because, although Boucek ( 1936, p. 39) stated that N eoaparchites was proposed for species of Aparchites with rounded cardinal angles, the original illustration and description 

of the type species, Primitia obsoleta Jones and Holl, 

1865, indicate the presence of an obtuse but welldeveloped posterior cardinal angle. Further study 

of N eoaparchites obsoletus is required to clarify the 

characteristics of the genus. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus APARCHITES Jones, 1889 

"Aparchites" sp. aff. "A." auriculiferus Rozhdestvenskaya, 1962 

Plate 10, figures 13, 14 

Aparchites auriculiferus Rozhdestvenskaya, 1962, p. 171-

172, pl. 1, figs. 1a, h; 2a, b. 

Description.-Lateral outline subcircular; dorsum 

straight, forming chord across circular outline of 

free margins. Hinge slightly incised ; cardinal angles 

obtuse but distinct. Valves equal; essentially no 

overlap on free margins. No marginal structures. 

Shell surface smooth. 

M aterial.-One incomplete carapace from the McCann Hill Chert. 

Measurements.-The single specimen is 1.85 mm 

long, 1.65 mm high, and 1.10 mm wide. 
SYSTEMAT'IC PALEONTOLOGY 29 

Types.-Figured specimen, USNM 173793. 

Discussion.-The specimen from the McCann Hill 

Chert appears to have a somewhat shorter hinge line 

than the specimens from the Eifelian beds of the 

southern Urals and western Bashkiria figured by 

Rozhdestvenskaya but is otherwise similar. Swartz 

(1969, p. 1238-1239), in restudying the type species 

of Aparchites, A. whiteavesi Jones, 1889, has suggested that the genus Aparchites be restricted to 

those species, that resemble the type species in having inward bending and thickening of the free margins. This type of marginal structure is not present 

in uA." auriculiferus nor in the probably related 

species uA." chuchlensis Pribyl, 1952. These species 

appear to constitute a new genus in the Paraparchitacea, but additional material is necessary before 

such a genus is described. 

Occurrence.-USGS collection 7032-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Superfamily KLOEDENELLACEA Ulrich and Bassler, 1908 

Family KLOEDENELLIDAE Ulrich and Bassler, 1908 

Genus EUKLOEDENELLA Ulrich and Bassler, 1923 

Eukloedenella recta n. sp. 

Plate· 11, :figu.res 19-24 

?Eukloedenella sp., Copeland in Norris, 1967a, p. 138; Copeland in Ludvigsen, 1970, p. 426 [part]. 

Description.-Lateral outline subovate to subquadrate, amplete to slightly postplete; dorsal outline of 

heteromorphic carapace subtriangular; tecnomorphs 

lanceolate in dorsal view. Dorsal and ventral margins subparallel; anterior margin evenly rounded; 

posterior margin straight to slightly convex. Posterior cardinal angle curved, but projection of dorsal 

and posterior margins meeting at about 90°. Essentially equivalved, but right valve overlaps left 

slightly around free margins. Stragulum on right 

valve overlaps left valve from anterior cardinal 

angle to midlength of carapace; hinge behind stragulum slightly incised. Greatest height and length near 

midpoint of carapace; greatest width posterior. S2 

deep, elongated, pitlike. No indication of Sl. Surface 

with some punctae or smooth. 

Material.-Four specimens from the Michelle Formation; 1 carapace and 10 single valves from the 

McCann Hill Chert. 

Measurements.-The three figured carapaces from 

the Michelle Formation are 0.95 mm long, 0.60 mm 

high, and 0.52 mm wide; 0.80 mm long, 0.50 mm 

high, and 0.42 mm wide; 0.90 mm long, 0.60 mm 

high, and 0.50 mm wide, respectively. 

Types.-Holotype, GSC 29443; paratypes, GSC 

29444, 29445, 29446, USNM 173794, 173795. 

Discussion.-Most of the specimens are heteromorphic; a few tecnomorphic single valves are less 

abruptly truncated posteriorly in dorsal view and 

have a more lanceolate outline. Eukloedenella recta 

belongs to the group of E. umbilicata Ulrich and 

Bassler, 1923, the type species of the genus. However, it differs from other species assigned to this 

group by Ulrich and Bassler ( 1923, p. 669-671) by 

its wide, truncated dorsal outline and right-over;..left 

overlap. E. dalhousiensis Copeland, 1962 is also similar to E. recta, but according to Copeland (1962, p. 

42, pl. 10, figs. 2, 3) the stragulum of E. dalhousiensis is narrow and on the left valve, although the 

right valve has a slight angulation over the left immediately above the median sulcus. The specific 

name of E. recta refers to the straight or rectangular 

outline of the species. 

Occurrence.-Ludvigsen collections 11-10, 11-11 

from the Michelle Formation, Blackstone River, Yukon Territory; USGS collections 7032-SD, 7033-SD, 

7037-SD from the McCann Hill Chert, Eagle (D-1) 

quadrangle, Alaska .. 

Eukloedenella soloensis n. sp. 

Plate' 11, figure 28 

?Eukloedenella sp., Copeland in Ludvigse.n, 1970, p. 426 

(part). 

Description.-Lateral outline subovate, postplete, 

with strong posterior inflation extending above 

hinge line. Posterior margin more broadly rounded 

than ante·rior. Slight indication of Sl. S2 anterior of 

midvalve (1.0 mm. from anterior end), deep, slitlike, 

not extending to dorsum. Posteroventral margin 

flattened, flangelike. Surface finely punctate. Interior 

showing fold of S1 and well-defined subovate depression of L2. 

Material.-One heteromorphic? right valve. 

Measurements.-The type specimen is 2.30 mm 

long and 1.50 mm high. 

Type.-Holotype, GSC 29442. 

Discussion.-This species is similar in lateral outline to Eukloedenella sulcifron,s Ulrich and Bassler, 

1923, as emended by Swartz (1933, female specimens, pl. 30, 6a, d) but the sulcus of E. soloensis is 

more slitlike and the surface is punctate. Swartz 

( 1933, p. 258) indicated that some specimens of E. 

sulcifron,s have "a suggestion of a shallow undefined 

anterior sulcus" like that present on E. soloen,sis. E. 

punctillosa Ulrich and Bassler, 1923, is also similar 

to E. soloensis in lateral outline but is more regularly 

punctate and has a deeper sulcus. E. soloensis is unusually large for a species of Eukloedenella. 

Occurrence.-Ludvigsen collection V -3, from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 
30 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

Genus POLONIELLA Giirich, 1896 

Subgenus FRAMELLA Weyant, 1968 

Poloniella (Framella) sp. aff. P. (F.) scheii Weyant, 1968 

Plate 11, figures 25-27 

Poloniella (Framella) scheii Weyant, 1968, p. 103-104, pl. 

1, figs. 4, 5. 

Description.-Lateral outline amplete to slightly 

preplete. Dorsal margin in lateral view slightly sinuous to straight; anterior margin smoothly curved ; 

ventral margin weakly concave; posterior margin 

more sharply curved than anterior margin. Narrow 

marginal sulcus connects dorsally with S1 and posteroventrally with S3. S1 about half height of valve, 

narrowed ventrally, inclined anteriorly; S2 also 

about half height of valve, narrow, more slanted 

anteriorly than S1; S3 arcuate, concave anteriorly, 

extending from dorsal margin nearly to ventral margin where it connects with marginal sulcus. L1 ovate 

in outline; L2 sinuous, narrow ventrally, slanted 

anteriorly and with a dorsoposterior extension; L3 

large, slanted anteriorly, curved posteriorly, with 

narrow, shallow diagonal groove inclined anteriorly; 

L4 crescentic, narrow, concave anteriorly. Surface 

smooth. Stragular process poorly developed. Heteromorph not known. 

M aterial.-Five specimens, comprising four left 

and one right tecnomorphic valves, from the McCann Hill Chert. 

Measurements.-Two figured specimens are 0.60 

mm long and 0.30 mm high, and 0.67 mm long and 

0.35 mm high, respectively. 

Types.-Figured specimens USNM 173796, 

173797, 173798. 

Discussion.-These specimens are most like the 

tecnomorphs of Poloniella (Framella) scheii described &.nd illustrated by Weyant (1968, p. 103, pl. 

1, fig. 5), from the lower part of the Blue Fiord 

Formation of Ellesmere Island. However, the specimens from the McCann Hill Chert differ from Weyant's specimens in the presence of the diagonal 

groove on L3. 

Occurrence.-USGS collection 7037-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Order PODOCOPIDA Miiller, 1894 

Suborder PODOCOPINA Sars, 1866 

Superfamily BAIRDIACEA Sars, 1888 

Family BAIRDIIDAE Sars, 1888 

Genus BAIRDIA M'Coy, 1844 

Bairdia sp. cf. B. leguminoides Ulrich, 1891 

Plate 11, figures 10, 11 

Bairdia leguminoides Ulrich, 1891, p. 197, pl. 17, figs. 5ac; (for a complete synonymy see Sohn, 1960 [1961], p. 

29). 

Description.-Carapace elongate, spindle-shaped, 

with short straight hinge line and dorsally inclined 

acuminate ends prolonged as spines on larger left 

valve. Posterior end more acute. Left valve overlaps 

right all around. Dorsal and ventral borders convex. 

Both valves inflated, maximum thickness near middle 

of valve. Surface smooth, possibly with some punctae. 

Material.-Two specimens from the Prongs Creek 

Formation, three specimens from the McCann Hill 

Chert. 

Measurements.-The figured specimen from the 

Prongs Creek Formation is 1.20 mm long and 0.50 

mm high; the figured specimen from the McCann 

Hill Chert is 1.15 mm. long, 0.55 mm high, and 0.45 

mm wide. 

Types.-Figured specimens, GSC 29508, USNM 

173799. 

Discussion.-The specimens from the McCann Hill 

Chert have a longer hinge than the holotype of Bairdia leguminoides Ulrich, 1891 (USNM 41788), and 

also appear to have a slight ventral flattening. They 

differ from B. mucronata Rozhdestvenskaya, 1960, 

in lacking a marked ventral overlap, and differ from 

B. emaciata Kesling and Kilgore, 1952, in being less 

elongate. 

Occurrence.-Ludvigsen collections V -3 and V -5 

from the Prongs Creek Formation, Solo Creek, Yukon Territory; USGS collections 7032-SD, 7037-SD, 

and 7038-SD from the McCann Hill Chert, Eagle 

(D-1) quadrangle, Alaska. 

Bairdia dejecta n. sp. 

Plate 11, figures 1-4 

Description.-Lateral outline bairdioid; dorsum 

curved ; dorsoanterior margin long and nearly 

straight; dorsoposterior margin short and concave; 

ventroanterior and ventroposterior margins gently 

curved ; ventral margin slightly concave. Carapace 

narrow and fusiform in dorsal outline. Left valve 

overlaps right all around. Dorsoanterior and dorsaposterior margins of left valve prolonged as downward slanting spines. Shell surface smooth. 

M aterial.-One complete and one broken carapace 

from the McCann Hill Chert. 

M easurements.-The holotype is 1.40 mm long, 

0.55 mm high, and 0.40 mm wide. 

Types. - Holotype, USNM 173800 ; para type, 

USNM 173801. 

Discussion.-This species differs from other species of Bairdia in having the terminal spines directed obliquely downward rather than upward as 

in the group of Bairdia leguminoides Ulrich, 1891. 

The specific name refers to the downcast appearance 

of the specimens. 
SYSTEMATIC PALEONTOLOGY 31 

Occurrence.-USGS collection 7037-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus RECTOBAIRDIA Sohn, 1961 

Rectobairdia sp. 

Plate 11, figure 15 

Description.-Lateral outline bairdioid; dorsum 

straight, more than half length of valve. Dorsoanterior margin concave, meeting smoothly curved 

ventroanterior margin at an angle above midheight 

of valve. Ventral margin slightly concave. Dorsoposterior margin concave, meeting smoothly curved 

ventroposterior margin at an acute angle about midheight of valve. Dorsal outline of valve smoothly 

curved. Surface smooth. 

M aterial.-One left valve from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 1.20 mm 

long and 0.52 mm high. 

Types.-Figured specimen, USNM 173802. 

Discussion.-The long straight dorsum indicates 

that this specimen should be assigned to the genus 

Rectobairdia Sohn, 1961. 

Occurrence.-USGS collection 6492-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus BAIRDIOLITES Croneis and Gale, 1939 

Bairdiolites? sohni n. sp. 

Plate 11, figures 5, 6, 9 

Description.-Lateral outline fusiform; dorsum 

curved. Dorsoanterior and dorsoposterior margins 

straight to slightly concave; ventroanterior margin 

gently curved; ventral margin straight to slightly 

convex; ventroposterior margin nearly straight. Left 

valve overlaps right all around. Anterior and posterior ends sharply acuminate, extended as spines on 

larger left valve. Both valves with vertical shoulders 

or ridges on anterior and posterior quarters. Dorsal 

outline subfusiform, with parallel sides. Surface 

smooth. Duplicature well developed. Muscle scar 

round. 

M aterial.-One carapace and three valves, all 

from the McCann Hill Chert. 

Measurements.-The holotype is 1.25 mm long, 

0.47 mm high, and 0.40 mm wide. 

Types.-Holotype, USNM 173803; paratypes, 

USNM 173804, 173805, 173806. 

Discussion.-Bairdiolites? sohni superficially resembles Bairdia leguminoides Ulrich, 1891, because 

of its acuminate or spinose ends, but differs in having the two characteristic vertical ridges, and a more 

rounded dorsum. This species is only questionably 

assigned to Bairdiolites because the other described 

species of Bairdiolites lack the very acuminate ends 

of B.? sohni. Bairdiolites has previously been considered to range from the Late Mississippian into 

the Early Pennsylvanian (Sohn, 1960 [1961], p. 69-

70) ; however, two Middle Devonian species illustrated by Rozhdestvenskaya (1962, pl. 21, figs. 3a-v, 

4a-b), Bairdia transversocostata Rozhdestvenskaya, 

1962, and Bairdia navicula Martinova and Polenova, 

1955, may belong in Bairdiolites rather than Bairdia. 

Occurrence.-USGS collections 6492-SD, 7037-

SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus NEWSOMITES Morris and Hill, 1952 

Newsomites? sp. 

Plate 14, figures 17, 18 

Description.-Lateral outline ovate, preplete; 

dorsum gently curved ; anterior margin broadly 

rounded ; ventral margin gently curved ; posterior 

margin sharply curved. Dorsal outline oval; maximum width median. Hinge incised ; larger left valve 

overlaps anterior and posterior ends of right valve. 

In end view, carapace tumid and asymmetrical; left 

valve markedly larger than right, overlaps and overreaches right ventrally. Surface smooth. 

M aterial.-One carapace from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0.47 mm 

long, 0.32 mm high, and 0.40 mm wide. 

Types.-Figured specimen, USNM 173847. 

Discussion.-The preplete lateral outline suggests 

that this may be a juvenile specimen. The normal 

pore canals reported by Lundin and Newton ( 1970, 

p. 33, 34) for Newsomites pertu1nidus Morris and 

Hill, 1952, and N. profusus Lundin and Newton, 

1970, have not been observed in the specimen from 

the McCann Hill Chert; they have probably been 

obliterated by this type of silicification. Although 

Newsomites was originally described from the Silurian of the Eastern United States, Polen ova ( 1968, 

p. 72-74) has included in this genus a species and 

three subspecies from the Devonian of Siberia, extending its range to Middle Devonian. 

Occurrence.-USGS collection 7037-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Family BEECHERELLIDAE Ulrich, 1894 

Genus ACANTHOSCAPHA Ulrich and Bassler, 1923 

Acanthoscapha sp. 

Plate 11, figures 12-14 

Description.-Lateral outline subfusiform; dorsum long, slightly concave at either end, terminating in spines ; anterior margin more sharply curved 
32 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

than posterior margin; ventral margin slightly concave. Hinge line more than half length of carapace; 

left valve slightly overreaches right dorsally and 

overlaps right in ventral concavity. Anteroventral 

and posteroventral margins of both valves meet as 

flattened flange. Posterior terminal spine on left 

valve nearly parallel to hinge line, anterior terminal 

spine inclined slightly upward. Dorsal outline fusiform. Shell surface smooth. 

M aterial.-One poorly preserved carapace from 

the McCann Hill Chert. 

M easurements.-The figured specimen is 1.25 mm 

long, 0.35 mm high, and 0.32 mm wide. 

Types.-Figured specimen, USNM 173807. 

Discussion.-This single carapace is close to Acanthoscapha navicula (Ulrich, 1891) from the Kalkberg Limestone of eastern New York, but is too 

poorly preserved to identify specifically. 

Occurrence.-USGS collection 7037-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Genus SHIDELERITES Morris and Hill, 1951 

Type species.-Shidelerites typus Morris and Hill, 

1951. 

Species included.-Shidelerites yukonensis n. sp. 

Revised diagnosis. - Asymmetrical beecherellid 

ostracodes with upright or posteriorly slanted spine 

on anterodorsal end of larger left valve, acuminate 

posterior, and laterally compressed anteroventral 

and posteroventral marginal areas. 

Discussion.-Morris and Hill (1951, p. 698) oriented Shidelerites with the anterior spine pointed 

downward in an anteroventral position, and compared the genus to the Cypridinidae but noted that 

it lacks the opening for protrusion of the anterior 

appendages characteristic of that family. Later, 

Triebel (1961, p. 347-348) examined topotype specimens and suggested that the genus should be reoriented so that the spine is anterodorsal in position 

and the sinuous margin is ventral. He proposed a 

revised diagnosis for Shidelerites (Triebel, 1961, p. 

348) which is freely translated as follows : 

Carapace middle siz;ed, without distinct sculpture, spindlesh.ap,ed in dors~al outline, elongated in la1ieral view, height 

les~s than half length. Anterior end broadly rounded, pos,terior 

end dTawn out into a sharp process that is somewhat below 

the straight hinge line. Dorsal margin of left valve with a 

triangular upward-pointing process on the anterior, which 

is l~acking on the right (valve). Ventral margin slightly 

bent in before the middle, projecting to the ends in flat 

arcs. Carapace in these parts somewhat compress~ed, in the 

remaining (p~arts) ap~p~roximately ~e;venly arched. Left valve 

larger than right, very widely overreaching at the anterodorsal margin with its triangular process, less overreaching on the remaining dorsal margin, somewhat overlapping 

ventral'ly in the oral region. Along the anterior margin and 

the terminal part of the ventral margin the valves lie 

simply together. Inner ~haracters unknown. 

Triebel (1961, p. 349) noted that Shidelerites had 

been tentatively referred to the Bairdiidae by Betty 

Kellett Nadeau (note in Morris and Hill, 1951, p. 

699) and stated that no better classification could be 

made until the internal characters of the valves were 

known. Having noted the resemblance of Shidelerites 

to Acanthoscapha Ulrich and Bassler, 1923 (=Allanella Boucek, 1936; see Berdan, 1960, p. 471), 

Triebel (1961, p. 349) concluded that Acanthoscapha 

also should be assigned to the Bairdiidae rather than 

the Beecherellidae. His reasons for removing Acanthoscapha from the Beecherellidae were based on the 

flattened venter of Beeche1"ella as opposed to the 

lateraJly compressed ventral margins of Acanthoscapha, the hollow ventroterminal spines of Beecherella as opposed to the dorsoterminal spines of 

Acanthoscapha, and the resemblance of Acanthoscapha to Bairdia. In our opinion, the flattened venter 

of Beecherella should not be considered a family 

characteristic, because this, feature appears at random in otherwise unrelated stocks. Acanthoscapha 

may well be ancestral to Bairdia, but should be retained in the Beecherellidae because of its long 

straight hinge line and attenuated outline. In addition to Shidelerites, Scaphina Polenova, 1968 and 

Celechovites Pokorny, 1950, should be included in 

the Beecherellidae, as suggested by Polenova (1968, 

p. 54). These genera all resemble Beecherella in 

having a long straight hinge line and height less 

than half the length of the valves. · 

To facilitate comparison with Shidelerites yukonensis n. sp., the holotype (USNM 116420) and a 

paratype (USNM 116421a) of Shidelerites typus 

Morris and Hill, 1951, are illustrated with the revised orientation on plate 11, figures 16, 17. 

Geologic range.-Waldron Shale (Middle Silurian) 

of Indiana ; Prongs Creek Formation (Lower Devonian) of Yukon Territory. 

Shidelerites yukonensis n. sp. 

Plate 11, figure 18 

Description.-Carapace elongate in lateral view, 

acuminate at each end; fusiform in dorsal view; oval 

in end view. Left valve larger than right, overreaching it dorsally and overlapping it midventrally and 

posteroventrally. Greatest height in posterior half, 

excepting anterior spine; greatest length in dorsal 

half. Hingeline straight, in anterior three-fourth of 

valve. Posterodorsal margin sloping ventrally to 

acuminate posterior cardinal corner, slightly concave; posteroventral margin evenly curved to midventer. Ventral margin concave at midlength, curv-
SYSTEMATIC PALEONTOLOGY 33 

ing smoothly into anteroventral and posteroventral 

margins. Anteroventral margin gently curved to 

meet vertical anterior margin. Anterior cardinal 

angle of right valve with slight dorsal angulation; 

anterior cardinal angle of left valve wrapped around 

that of right valve and produced into strong vertically directed spine or horn. Lateral surface 

smooth ; anteroventral and posteroventral areas 

slightly concave parallel with the free margin, anteroventral area apparently larger. Internally, duplicature visible through hole in left valve continuous 

at least in posterior half of valve as fine shelflike 

thickening of free margin. 

Mat erial. - One complete carapace from the 

Prongs Creek Formation. 

Measurements.-The holotype is 1.55 mm long and 

0.60 mm high. 

Types.-Holotype, GSC 29440. 

Discussion.-Shidelerites yukonensis differs from 

S. typus Morris and Hill, 1951, the type species of 

the genus, in having the anterior margin nearly vertical rather than smoothly curved, and in having the 

anterodorsal spine erect rather than slanted posteriorly. 

Occurence.-Ludvigsen collection V -3, Prongs 

Creek Formation, Solo Creek, Yukon Territory. 

Genus BEECHERELLA Ulrich, 1891 

Beecherella? sp. 

Plate 11, figures 7, 8 

Description.-Lateral outline subtrapezoidal; both 

ends acuminate; greatest length ventral; greatest 

height in anterior quarter. Hinge line straight, not 

parallel to ventral margin, sloping slightly posteriorly. Venter flat, extended laterally as ala with 

minute posteriorly directed spine. Dorsal outline subtriangular. Shell surface smooth. Duplicature poorly 

developed. 

Material.-One right valve from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0.55 mm 

long, 0.25 mm high, and 0.25 mm wide. 

Types.-Figured specimen, USNM 173808. 

Discussion.-This single right valve is suggestive 

of Beecherella in its lateral outline and flattened 

venter, but the relatively short hinge, poorly developed duplicature, and wide alate process are not 

typical of the genus Beecherella as represented by 

the type species, B. carinata Ulrich, 1891. The flattened venter and alate process are like similar structures developed in the genus Pseudocyproides Morris and Hill, 1952, but the type species of this genus, 

P. alatus, is described by Morris and Hill (1952, p. 

16, pl. 1, fig. 4) as having a strongly arched dorsum. 

Examination of the holotype of P. alatus Morris and 

Hill, 1952 (USNM 123230) suggests that the resemblance is homeomorphic. 

Occurrence.-USGS collection 7037-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Superfamily CYPRIDACEA Baird, 1845 

Family UNCERTAIN 

Genus CAMDENIDEA Swain, 1953 

Camdenidea sp. 

Plate 13, figures, 1-4 

Description.-Lateral outline subreniform; dorsal 

margin smoothly curved, merging with more sharply 

curved anterior margin; ventral margin straight to 

concave; posterior margin acuminate. Dorsal outline 

subelliptical. Right valve overlaps left around free 

margins; left valve with crescentic depressed areas 

on anterior and posterior margins which are absent 

on right valve. Surface smooth. Duplicature narow. 

Material.-Two left valves, one right valve, and 

one carapace from the McCann Hill Chert. 

Measurements.-The carapace is 0.55 mm long, 

0.27 mm high, and 0.32 mm wide. 

Types.-Figured specimens, USNM 173812, 

173813, 173814. 

Discussion.-These small specimens differ from 

Camdenidea camdenensis Swain, 1953, the type species of the genus, in having the right valve larger 

than the left and in having anteroventral and posteroventral compressed areas on the left valve only. 

A formal name is not proposed for them here because of the probability that they are immature 

individuals. 

Occurrence.-USGS collection 7037 -SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Superfamily indet. 

Family TRICORNINIDAE Blumenstengel, 1965 

Genus TRICORNINA Boucek, 1936 

"T ricornina" caurina n. sp. 

Plate 12, figures 1-3 

Description. - Carapace boat-shaped; greatest 

length along dorsal margin; posterior cardinal angle 

acuminate; posteroventral margin sloping to relatively straight ventral margin; anterior cardinal 

angle more than 90°, anterior margin broadly 

rounded. Anterior and posterior margins with narrow marginal flange. Surface smooth, evenly curved 

from lateral margins to very long hollow spine at 

midvalve. Spine base large, diameter about threequarters height of valve; spine extending at right 

angles to valve, tapering distally with slight dorsal 

and posterior swing. 
34 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

M aterial.-One right valve from the Prongs Creek 

Formation. 

Measurements.-The holotype is 1.35 mm long and 

0.60 mm high. The spine is 0.85 mm long. 

Types.-Holotype, GSC 29448. 

Discussion.-The size and orientation of the lateral spine of this species is extremely distinctive. 

The anterodorsal corner of the valve is slightly 

broken so it is impossible to determine if an anterodorsal spine or projection should be present. 

Occurrence.-Ludvigsen collection V -3, from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

T ricomina sp. 

Plate 12, figure, 4 

Description.-Valve boat-shaped; dorsal margin 

greatest length; posterior angle acuminate; anterior 

angle with strong, dorsally directed spine. Surface 

smooth, with long straight only slightly tapering 

spine near mid ventral part of valve. Spine projects 

posterolaterally at about 45 o to the valve surface'. 

Material.-One small incomplete (now broken) 

left valve from the Michelle Formation. 

Measurements.-Specimen broken, not measured. 

Types.-Figured specimen, GSC 29510. 

Discussion.-This specimen is too poorly preserved 

for adequate comparison with other tricorninids. It 

has the general features of the genus. 

Occurrence.-Ludvigsen collection I-3 from the 

Michelle Formation, Hart River, Yukon Territory. 

Genus BICORNINA Jordan, 1964 

Bicornina sp. 

Plate, 12, figures 5-7 

Description.-Lateral outline boat-shaped; dorsal 

margin straight to slightly convex; free, margins 

smoothly curved. Anterior cardinal angle acute, produced as spine on larger left valve; posterior cardinal angle blunt or rounded. Dorsal outline arrowshaped; posteroventral half of both valves occupied 

by large hollow spine which projects posteriorly and 

curves dorsally, extending beyond posterior margin 

of carapace. Shell surface smooth. No duplicature. 

M aterial.-One broken, poorly preserved carapace, 

two left valves, and one right valve from the McCann Hill Chert. 

Measurements.-The figured left valve is 0.65 mm 

long without theanterior spine and 0.35 mm high .. 

The length, including both spines, is 0.85 mm. 

Types.-Figured specimens, USNM 173809, 

173810. 

Discussion.-Jordan (1964, p. 58-59) distinguished Bicornina from Tricornina Boucek, 1936 on 

the basis that Bicornina lacks the posterodorsal spine 

of Tricornina. The blunt posterior angle of the specimens from the McCann Hill Chert suggests that 

they belong in Bicornina. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7037-SD, 7038-SD from the McCann Hill Chert, 

Eagle (D-1) quadrangle, Alaska. 

Fa'mily BEROUNELLIDAE Sobn and Berdan, 1960 

Genus BEROUNELLA Boucek, 1936 

Berounella sp. aff. B. minuta Blumenstengel, 1970 

Plate 12, figures 8, 9 

Berounella minuta Blumenstengel, 1970, p. 19-20, pl. 1, figs. 

10, 11. 

Description.-Lateral outline subtrapezoidal; dorsal margin straight to slightly concave; ventral margin straight, parallel to dorsal margin; anterior margin slightly sinuous; posterior margin concave, curving posteriorly parallel to dorsal margin. Posterior 

end of valve drawn out into long hemitube characteristic of genus. Valve trilobate; L1 nearly vertical, 

extending from. anterodorsal to anteroventral margins of valve; L2 knoblike, anteromedian in position; 

L3 curved obliquely forward. L3 with long hollow 

spine arising from ventral part and projecting posteriorly and slightly dorsally. Small spine at midheight of posterior margin. Three, possibly four, 

small digitate spines on anterodorsal part of anterior 

margin. Anteroventral and posteroventral margins 

slightly flattened. Duplicature best developed on 

anterior and posterior margins. 

M aterial.-One right valve from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0.95 mm 

long, including the spine, and 0.30 mm high. 

Types.-Figured specimen, USNM 173811. 

Discussion.-The single right valve from the McCann Hill Chert resembles Berounella minuta Blumenstengel, 1970, in having a long prominent spine 

on L3, which is apparently not as well developed, if 

present, on the other species of B erounella listed by 

Blumenstengel (1965, p. 56). However, our specimen 

differs from B. minuta in the arrangement of the 

anterodorsal spines. Blumenstengel (1970, p. 19, pl. 

1, fig. 10) described and illustrated B. minuta as 

having a prominent anterodorsal spine which curves 

upward and forward, and a second smaller spine 

beneath this. Our specimen has three short spines 

on the anterodorsal part of the anterior margin. A 

fourth may have been present and then broken off, 

but it could not have been as prominent as the anterodorsal spine shown by Blumenstengel. 

Occurence.-VSGS collection 7037-SD, from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 
SYSTEMATIC PALEONTOLOGY 35 

Suborder METACOPINA Sylvester-Bradley, 1961 

Superfamily HEALDIACEA Harlton, 1933 

Family BAIRDIOCYPRIDIDAE Shaver, 1961 

Genus BAIRDIOCYPRIS Kegel, 1932 

Bairdiocypris? sp. cf. 8.1 cordiformis Rozhdestvenskaya, 1959 

Plate 12, figures 10, 11 

Bairdiocypris( ?) cordiformis Rozhdestvenskaya, 1959, p. 167, 

pl. 25, figs. 1a, b; 2a, b. 

Description.-Carapace reniform to heart-shaped ; 

greatest length in ventral third; greatest height 

slightly anterior of midlength. Left valve overlaps 

right along dorsal margin; greatest overlap posterodorsal. Right valve with low marginal flange at 

anteroventral and posteroventral corners ; flange not 

present midventrally where both valves are slightly 

concave. 

M aterial.-One carapace from the Prongs Creek 

Formation and one from the McCann Hill Chert. 

Measurements.-The specimen from the Prongs 

Creek Formation is 0.90 mm long and 0.70 mm high. 

Types.-Figured specimens, GSC 29450, USNM 

173840. 

Discussion.-The figured specimens are very similar to Bairdiocypris? cordiformis from the Biya beds 

(Eifelian) of Bashkiria; the Yukon specimen, however, has its greatest height slightly anterior of midvalve, that of B.? cordiformis is slightly posterior of 

mid valve. 

Occurrence.-Ludvigsen collection V -3 from the 

Prongs Creek Formation, Solo Creek, Yukon Territory; USGS collection 7037-SD from the McCann 

Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Bairdiocypris sp. 

Plate 12, figure 12 

"Bythoc,ypris" sp., Copeland in Norris, l967·a, p. 128, 130, 

138, 140, 141. 

Description.-Carapace subovate in lateral view, 

slightly concave midventrally, regularly convex dorsally. Left valve overlapping right along all margins; least overlap at anteroventral margin. Hinge 

curved, about one-third greatest length, inclined posteroventrally, and situated in posterior half of valve. 

Surface smooth. 

Material.-More than 10 specimens from the 

Prongs Creek Formation. 

Measurements.-The figured specimen is 1.20 mm 

long and 0.80 mm high. 

Types.-Figured specimen, GSC 29476. 

Discussion.-Some variation in overlap occurs in 

this species, some specimens showing more left-overright overlap posteroventrally. In general, however, 

the greatest overlap is as indicated above. 

Occurrence.-Ludvigsen collections V -3, V -4, V -5, 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Genus KURESAARIA Adamczak, 1967 

Kuresaaria blackstonensis n. sp. 

Plate 12, figures 13-25 

Bairdiocypris sp., Bevdan in Churkin and Brabb, 19·68, table 

1, pl. 4, fig. 8 [imprint 1967]; Copeland in Ludvigsen, 

1970, p. 426 (part). 

Description.-Carapace subovate to subtriangular 

in lateral view; anterior and posterior margins 

evenly rounded; dorsal margin highly arched ; ventral margin convex. Carapace fusiform in dorsal 

view. Left valve larger than right, overlapping right 

all around ; greatest overlap along dorsum and 

venter. Valves moderately convex, smooth; greatest 

thickness median in ventral half. Hinge straight, 

sloping posteriorly, about one-half greatest length of 

valve, consisting of simple groove and ridge hingement. Left valve with contact groove terminating in 

two ventral stop ridges, not present midventrally. 

Right valve more angular than left. Hinge of right 

valve prominent, with abrupt terminal angulations; 

anterior margin extended ventrally, ventral margin 

sloping upward to regularly curved posterior margin. Muscle scar on median inner surface, circular 

in outline but less distinct on its dorsal edge, apparently consisting of numerous small scars. Shell very 

thick. 

Material.-Nine specimens from. the Michelle Formation; three specimens from the· Prongs Creek Formation ; more than 90 specimens from the McCann 

Hill Chert. 

Measurements.-Three left valves from the Michelle Formation are 1.35 mm long and 0.95 mm 

high, 1.02 mm long and 0.70 mm high, and 1.10 mm 

long and 0.75 mm high, respectively. Two right 

valves from the Michelle Formation are 1.32 mm 

long and 0.80 mm high, and 1.25 mm long and 0. 78 

mm high, respectively. 

Types.-Holotype, GSC 29487; paratypes, GSC 

29488, 29489, 29490, 29491, 29492, 29493, USNM 

170343, 173815, 173816, 173817, 173818. 

Discussion.-This species is considered to belong 

in K uresaaria because of the character of the contact groove and ventral stop ridges, although the 

hinge is straighter than that of typical Kuresaaria. 

It differs from K. gotlandica Adamczak, 1967, the 

type species of the genus, in having the greatest 

height more median and lacking the shallow anterodorsal depression of K. gotlandica. An unusually 

thick shell has been demonstrated for K. gotlandica 

by Adamczak (1967, figs. 3C, D) ; this condition prevails inK. blackstonensis also. One specimen (pl. 12, 

fig. 23) from the McCann Hill Chert, which is imperfectly silicified, shows structures that appear to 

be siliceous fillings of small pore canals in the shell 
36 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

wall. These are smaller and more closely spaced than 

those of the pachydomellids. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, 7037-SD, and 7038-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; 

Ludvigsen collections 11-10, 11-13, 11-14, and IV-3 

from the Michelle Formation, Blackstone River, Yukon Territory; Ludvigsen collection V -3 from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Genus BAIRDIOHEALDITES McGill, 1968 

Bairdiohealdites? scapulatus n. sp. 

Plate 13, figures 8-11 

Description.-Lateral outline subreniform; dorsal 

outline sublanceolate. Dorsal margin smoothly 

curved, sloping abruptly into short, straight posterodorsal margin ; posteroventral margin sharply 

curved; ventral margin straight to slightly concave; 

anterior margin sharply curved, merging smoothly 

into gently curved anterodorsal slope. Left valve 

overlaps right around free margins, overreaches 

right along straight hingeline. Greatest height median to posteromedian; greatest width in posterior 

third of carapace. Shoulderlike swelling or ridge on 

posterodorsal third of both valves, most prominent 

on right valve. Lateral surface of both valves flattened anterior to shoulder. Surface smooth. Muscle 

scar median to anteromedian in position, round, composed of many small flecks. Marginal structures not 

observed. 

Material.-More than 15 specimens from the McCann Hill Chert. 

Measurements.-The holotype is 1.60 mm long, 

1.00 mm high, and 0.80 mm wide (maximum width 

through shoulders) . 

Types.-Holotype, USNM 173819; paratypes, 

USNM 173820, 173821, 173822, 173823, 173824. 

Discussion.-This species is questionably assigned 

to Bairdiohealdites because of its overlap and outline, especially the abrupt posterodorsal slope, and 

because of the distinct circular muscle scar, which 

was noted by McGill (1967, p. 1080) in the type 

species of the genus, B. rozhdestvenskayae. Bairdiohealdites? scapulatus, however, differs from other 

species referred to the genus in having a distinct 

posterodorsal shoulder. Although this character suggests a relationship to Condracypris Roth, 1929, 

Lundin ( 1968, p. 57-59) has noted that Condracypris 

has a duplicature, a structure that is lacking in B.? 

scapulatus. Furthermore, species assigned to Condracypris characteristically have the greatest height 

anterior to the midlength, whereas in B.? scapulatus 

the greatest height is posterior to the midlength. 

Lundin (1968, p. 58) does not consider the elongate 

nodes of Condracypris binoda Roth, 1929, the type 

species of the genus, to be a generic character. It 

appears likely that these features may develop in 

other genera. The specific name of B.? scapulatus 

refers to the posterodorsal shoulder characteristic 

of the species. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, and 7037-SD from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska. 

Genus PRAEPILA TINA Polenova, 1970 

Praepilatina sp. aff. P. praepilata sibirica Polenova, 1970 

Plate 13, figures 5-7 

Description. -Lateral outline subsemicircular; 

dorsal margin nearly a semicircle; posterior margin 

steeply inclined; ventral margin straight to slightly 

concave; anterior margin sharply rounded. Left 

valve apparently overlaps right; posteroventral margin of left valve sharply rounded ; posteroventral 

margin of right valve extended as small spine or 

angulation. Valves evenly convex in dorsal view. Surface smooth. 

M aterial.-About 12 valves, many broken, from 

the McCann Hill Chert. 

Measurements.-The two figured right valves are 

0. 75 mm long and 0.50 mm high, and 0. 75 mm long 

and 0.50 mm high, respectively. The figured left 

valve is 1.10 mm long and 0.85 mm high. 

Types.-Figured specimens, USNM 173825, 

173826, 173827. 

Discussion.-This form appears to be most similar to Praepilatina praepilata s·ibirica from the 

Lower Devonian of the Altai-Sayan region of Siberia 

as illustrated by Polenova ( 1970, pl. 24, figs. 3, 5 ) 

in the posteroventral projection of the right valve. 

Polenova (1970, p. 49) distinguished P. praepilata 

sibirica from P. praepilata praepilata (Polenova, 

1960), the type species, on the basis that the left 

valve showed more dorsal overlap in P. p. sibirica. 

Unfortunately, we have no carapaces and hence cannot determine the degree of overlap; however, figures of P. p. praepilata (Polenova, 1960, pl. 8, fig. 5; 

1970, pl. 24, fig. 2) show a rounded rather than 

acuminate posteroventral margin. 

Occurrence.-USGS collections 7037-SD, 7038-

SD from the Eagle (D-1) quadrangle, Alaska. The 

holotype of P. p. sibirica is from the Lower Devonian upper Krekov beds of the Salair district in 

Siberia. 

Family BARYCHILINIDAE Ulrich, 1894 

Genus BARYCHILINA Ulrich, 1891 

Barychilina? sp. 

Plate 14, figure 19 

Description. - Valve subrhomboidal; hingeline 

straight; overlap unknown. Deep elongate sulcus ex-
SYSTEMATIC PALEONTOLOGY 37 

tending from dorsal margin about one-third the distance to the ventral border. Shallow depression on 

anterodorsal corner; L1 broad, tumid. Surface of 

valves finely punctate with longitudinal ridges in 

posterior half, depressed areas between ridges finely 

reticulate. 

M aterial.-One right valve from the Michelle Formation. 

Measurements.-The figured specimen is 0.90 mm 

long and 0.50 mm high. 

Types.-Figured specimen, GSC 29451. 

Discussion.-This species is very similar to Barychilina? opisthorhysa (Kesling and Kilgore, 1952), 

but has a shorter sulcus and finer reticulate posterior 

ridges. 

Occurrence.-Ludvigsen collection 1-3 from the 

Michelle Formation, Hart River, Yukon Territory. 

Genus TRYPETERA Kesling, 1954 

Trypetera 1 sp. 

Plate 14, figure 21 

Description.-Dorsal margin straight; anterior 

margin smoothly curved ; ventral margin gently 

curved; posterior margin broken. Deep round pit in 

anterodorsal part of right valve. Surface ornamentation consisting of large round punctae. 

Material.-One broken right valve from the Michelle Formation. 

Types.-Figured specimen, GSC 29447. 

Discussion.-This form is known only from the 

anterior part of a right valve. The identification of 

this specimen is extremely questionable but appears 

plausible on the basis of the description of Trypetera 

by Kesling (1954, p. 178). No direct comparison with 

Trypetera barathrota Kesling, 1954, is attempted. 

Occurrence.-Ludvigsen collection 11-13 from the 

Michelle Formation, Blackstone River, Yukon Territory. 

Family CAVELLINIDAE Egorov, 1950 

Genus VORONINA Polenova, 1952 

Voronina sp. cf. V. inventa Rozhdestvenskaya, 1962 

Plate 13, figures 12-17 

Description.-Lateral outline ovate; dorsal and 

ventral margins smoothly curved ; anterior margin 

sharply curved; posterior margin bluntly subangulate. Carapace markedly asymmetrical; right valve 

larger than left, overlaps it all around. Greatest overlap dorsal; ventral overlap slightly less than dorsal 

overlap. Junction between lateral surface and marginal overlapping surface of right valve bluntly subangular; low keel may be developed at junction dorsally. Lateral surface of right valve flattened in end 

view; lateral surface of left valve smoothly convex. 

Dorsal and ventral margins of left valve nearly 

parallel ; ends asymmetrically rounded, sharpest 

curve of anterior end ventral and sharpest curve of 

posterior end dorsal in position, so that lateral outline of left valve approximates a parallelogram. Interior of right valve with contact groove around free 

margins; hinge broken on only single valve (USNM. 

173829) but apparently a simple sharp edge in right 

valve. Low swelling in anterodorsal half of right 

valve, anterior to which is possible oval muscle scar 

composed of large individual flecks. Exterior surface of valves smooth or finely punctate. 

Mat erial.-Two carapaces and a right valve from 

the McCann Hill Chert. 

Measurements.-The figured carapace (pl. 13, figs. 

12-14) is 1.85 mm long, 1.35 mm high and 0.85 mm 

wide. 

Types.-Figured specimens, USNM 173828, 

173829, 173830. 

Discussion.-This form is very close to Voronina 

inventa Rozhdestvenskaya, 1962, but is apparently 

relatively shorter and higher. Rozhdestvenskaya 

(1962, p. 205) considered the right valve of V. inventa to be larger than the left, the reverse of the 

orientation suggested by Polenova (1952, p. 140) for 

V. voronensis Polenova, 1952, the type species of the 

genus. The specimens from Alaska appear to agree 

with Rozhdestvenskaya's orientation for V. inventa, 

as the presumed muscle scar is anterior in position 

and the greatest width is postmedian. Tolmachoff 

(1926, p. 36) described Ellesmeria ovata, the type 

species of his genus Ellesmeria, as having the right 

valve larger than the left, with greater overlap dorsally and ventrally than on the anterior and posterior ends; however, he also described E. ovata as 

having a shallow anterior sulcus on both valves, a 

feature which is not present in Voronina. Should the 

presence of a sulcus prove to be nondiagnostic for 

Ellesmeria, V. inventa Rozhdestvenskaya, 1962, and 

the Alaskan specimens might be considered to belong 

to Ellesmeria. 

Both Polenova (1952, p. 141) and Rozhdestvenskaya ( 1962, p. 205) described dimorphism in Voronina, the tecnomorphs being flatter than the heteromorphs in dorsal view. The specimens from1 Alaska 

are considered to be heteromorphs ·by comparison 

with V. inventa; no tecnomorphic specimens have 

been found. 

Occurrence.-USGS collections 6492-SD and 

7032-SD, from the McCann Hill Chert, Eagle (D-1) 

quadrangle, Alaska. 

Genus CAVELLINA Coryell, 1928 

Subgenus INVISIBILA Polenova, 1960 

Cavellina (lnvisibila) 1 sp. 

Plate 14, figures 12-14 

Description.-Lateral outline suboval; dorsal margin gently curved ; anterior and posterior ends evenly 
38 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 

rounded; ventral margin straight or slightly concave. 

Carapace narrow in dorsal view. Shell thin, shell surface smooth. 

Material.-One sheared carapace and one right 

valve from the McCann Hill Chert. 

Measurements.-The right valve of the carapace 

(USNM 173848) is 0.75 mm long and 0.40 mm high. 

Types.-Figured specimens, USNM 173848, 

173849. 

Discussion.-The valves of the only carapace are 

sheared so that the character of the overlap and 

hingement cannot be determined. The general outline of the valves, however, resembles that of GavelUna (lnvisibila) porrecta Polenova, 1960 (p. 33-34, 

pl. 5, fig. 5). 

Occurrence.-VSGS collection 7037-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Family PACHYDOMELLIDAE Berdan and Sohn, 1961 

Genus TUBULIBAIRDIA Swartz, 1936 

Tubulibairdia sp. 

Plate 14, figures 27-29 

Description.-Lateral outline of carapace suboval; 

dorsal margin broadly curved ; anterior and posterior ends more closely curved ; ventral margin 

gently curved to straight. Valves unequal; left valve 

overlaps right on free margins, narrowly on anterior 

and posterior ends and broadly ventrally, and overreaches right slightly dorsally. Hinge incised, half 

or more length of valve. Surface smooth. 

M aterial.-One specimen from the Prongs Creek 

Formation; more than 15 specimens from the McCann Hill Chert. 

Measurements.-The figured specimen from the 

McCann Hill Chert is 1.25 mm. long, 0. 75 mm high, 

and 0.80 mm wide. 

Types.-Figured specimens, USNM 173831, GSC 

29475. 

Discussion.-Most of the specimens of Tubulibairdia from the McCann Hill Chert are noticeably 

poorly silicified in comparison to specimens of other 

genera in the same collections ; some are steinkerns 

that show fillings of the characteristic tubules of 

Tubulibairdia. This poor preservation may be due to 

the coarsely porous character of the shell walls. The 

material at hand is not adequate to discriminate the 

species. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7033-SD, and 7037 -SD from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen 

collection V -3, Prongs Creek Formation, Solo 

Creek, Yukon Territory. 

Pacbydomellid indet. 1 

Plate 14, figures 24-26 

Description.-Lateral and dorsal outlines of carapace subovate; anterior outline roughly heartshaped. Valves asymmetrical ; left much larger than 

right, overreaching it dorsally and overlapping it 

ventrally and around ends. Hinge line deeply incised. Carapace very tumid ; width greater than 

height, greatest width postmedian. Posterior of left 

valve with conspicuous compressed area; posterior 

of right valve also compressed, but not as much. 

Both anterior and posterior ends sharply rounded. 

Shell surface smooth or very faintly striatopunctate. 

Material.-Two broken carapaces and nine left 

valves from the McCann Hill Chert. 

Measurements.-The figured carapace is 0.60 mm 

long, 0.40 mm high, and 0.45 mm wide. 

Types.-Figured specimens, USNM 173832, 

173833. 

Discussion.-The pronounced asymmetry, incised 

hinge line, and thick shell suggest that these specimens belong in the Pachydomellidae, although the 

preservation is such that the characteristic tubules 

of that family cannot be seen. The compressed posterior of both valves and the tumidity are characteristic of the genus Newsomites Morris and Hill, 1952, 

which Lundin and Newton (1970, p. 33, 34) consider 

similar to the pachydomellids although retaining it 

in the Bairdiidae pending further study. However, 

species assigned to Newsomites, such as N. pertumidus Morris and Hill, 1952, N. profusus Lundin 

and Newton, 1970, and N. notabilis (Polenova, 1955) 

have the greatest thickness median rather than postmedian as in the pachydomellids and the specimens 

from the McCann Hill Chert. 

Occurrence.-VSGS collections 6492-SD, 7032-

SD, 7037-SD, and 7038-SD from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska. 

Pachydomellid indet. 2 

Plate 14, figure 23 

Description.-Lateral outline suboval; dorsum 

curved ; anterior end evenly curved ; ventral outline 

straight to gently convex; posterior end more acute 

than anterior. Hinge straight, incised. Surface covered with spines, which are longest at ventral edge 

of lateral surface and shortest on flattened venter. 

Shell thick, apparently tubulous. 

Mat erial.-Two left valves from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 0.55 mm 

long and 0.30 mm high. 

Types.-Figured specimen, USNM 173846~ 

Discussion.-These specimens resemble the inter-
SYSTEMATIC PALEONTOLOGY 89 

nal molds of Tubulibairdia in which the shell is dissolved and the traces of the filled tubules appear as 

spines. However, in these valves the shell is preserved and appears to be tubulous, although the silification obscures the structure. They may represent 

a Tubulibairdia-like form in which the setae which 

were presumably in the tubules became sheathed in 

spines, although the preservation is such that the 

spines do not appear to be hollow. 

Occurrence.-USGS collection 7037-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Superfamily QUASILLITACEA Coryell and Malkin, 1936 

Family QUASILLITIDAE Coryell and Malkin, 1936 

Genus ERIELLA Stewart and Hendrix, 1945 

Eriella1 sp. 

Plate 14, figures 1, 2 

Description.-Right valve subovate in lateral outline; greatest height median; anterior and posterior 

margins equally rounded. Hinge long, nearly onethird the greatest length, situated near median and 

incised below dorsal shoulder. Surface coarsely reticulate, reticulae in concentric rows about a central 

reticulate area near mid valve; central pit, if present, 

the same size as surrounding reticulae. 

M aterial.-One right valve from the Michelle Formation, four specimens from the McCann Hill Chert. 

Measurements.-The figured specimen from the 

Michelle Formation is 0.50 mm long and 0.30 mm 

high. 

Types.-Figured specimens, GSC 29452, USNM 

173834. 

Discussion.-This species is smaller, more ovate 

and more coarsely reticulate than the type species, 

Eriella robusta Stewart and Hendrix, 1945, from the 

"Plum Brook Formation" of Ohio. The specimens 

from the McCann Hill Chert are somewhat more 

finely reticulate than the specimen from the Michelle, and may not be conspecific. The figured right 

valve from the McCann Hill Chert has a small posteroventral spine as described for Eriella. 

Occurrence.-Ludvigsen collection I-3 from the 

Michelle Formation, Hart River, Yukon Territory; 

USGS collection 7037-SD, McCann Hill Chert, Eagle 

(D-1) quadrangle, Alaska. 

Superfamily THLIPSURACEA Ulrich, 1894 

Family THLIPSURIDAE Ulrich, 1894 

Genus NEOCRA TERELLINA Krandijevsky, 1968 

Neocraterellina 1 crescentifera n. sp. 

Plate 14, figures 5-11 

Healdia sp., Berdan in Churkin and Brahb, 1968, table 1, 

pl. 4, fig. 1. [Imprint 1967.] 

Description. - Lateral outline ovate; dorsum 

smoothly curved ; anterior margin sharply rounded; 

ventral margin nearly straight to slightly convex; 

posterior margin smoothly curved. Left valve larger 

than right, overreaching it dorsally and overlapping 

it distinctly on posterior and ventral margins, overlapping it narrowly on anterior margin. Dorsal outline subovate; hinge line narrowly incised. Greatest 

length median ; greatest height slightly posteromedian ; greatest width posteromedian. Left valve with 

crescentic groove subparallel to posterior margin, 

extending from posterodorsal third of valve to posteroventral quarter. Right valve with similar, shorter 

groove in posterior third which does not extend as 

far dorsally as groove in left valve. Shell surface 

otherwise smooth. Muscle scar apparently oval, situated on low ridge or swelling which is not seen on 

exterior of valve. Hinge short, straight; details of 

hingement not known. Contact groove present 

around free margins of left valve, apparently interrupted ventrally. 

M aterial.-Eight carapaces and five single valves 

from the McCann Hill Chert. 

Measurements.-The holotype is 0.75 mm long, 

0.45 mm high, and 0.40 mm wide. 

Types.-Holotype, USNM 173835; paratypes, 

USNM 170336, 173836, 173837, 173838. 

Discussion.-This species was originally assigned 

to H ealdia because of the crescentic posterior groove ; 

however, it lacks the characteristic posterodorsal 

flattening of true H ealdia. Further study of the muscle scar and the character of the groove suggests that 

N eocraterellina? crescentifera is a thlipsurid. Krandijevsky (1968, p. 72) proposed the genus Neocraterellina, with Craterellina oblonga Ulrich and Bassler, 1913, as the type species, for thlipsurids with 

one curved or horseshoe-shaped or round closed furrow. Thlipsurella orthoclefta Swartz, 1932, was included in this genus by Krandijevsky (1968, p. 72). 

This species is comparable to N.? crescentifera in 

having a single posterior groove, but the groove of 

N. orthoclefta is straight rather than crescentic as 

inN.? crescentifera. The holotype of N. orthoclefta 

(USNM 86504) from the Shriver Chert in Pennsylvania appears to have a more strongly curved dorsum than illustrated by Swartz (1932, pl. 11, fig. 

3a) and thus is closer to N.? crescentije1·a than is 

shown by the figures of both species. 

Occurrence.-USGS collections 6492-SD, 7032-

SD, 7033-SD, and 7037-SD from the McCann Hill 

Chert, Eagle (D-1) quadrangle, Alaska. 

Family indet. 

Genus MICROCHEILINELLA Geis, 1933 

Microcheilinella 1 sp. 

Plate 14, figures 3, 4 

Description.-Carapace small, tumid, subovate in 
40 OSTRACODES FROM LOWER DEVONIAN FORMA.TIONS IN ALASKA AND YUKON TERRITORY 

lateral view. Left valve overlapping right all around 

except dorsally. Hinge half greatest length, occupying middorsal area, incised between shoulders of 

both valves. Greatest height and length median; 

greatest width in posterior third. Surface smooth. 

Mat erial.-Two specimens from the Prongs Creek 

Formation. 

Measurements.-The figured specimens are 0.60 

mm long, 0.34 mm high, and 0.35 mm wide. 

Types.-Figured specimens, GSC 29514, 29515. 

Discussion.-This species is not readily distinguishable from numerous other small ovate smooth 

ostracodes of microcheilinellid type. The hinge of 

this species may be more incised than that of many 

other species, but this could be a matter of preservation. Until a complete revision of this genus is 

attempted, it is felt that a specific designation is 

unnecessary. 

Occurrence.-Ludvigsen collection V -3 from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 

Ostracode indet. 1 

Plate 14, figure 20 

Description.-Hinge line straight; prominent median sulcus in anterior half of valve; sulcus extends 

nearly to mid valve. Presulcal node ovate, indistinct; 

slight indication of S1 in anterodorsal corner of 

valve. Lateral outline subovate. Surface slightly 

papillose with faint posterior lineation. Anteroventral flange or spur projecting from right valve margin in position of spur on Hanaites. Pronounced 

tubercle present in posterodorsal quarter of valve. 

No other marginal structure observed. 

Material.-Two incomplete specimens from the 

Michelle Formation. 

Measurements.-The incomplete figured specimen 

is 0.90 mm long and 0.55 mm high. 

Types.-Figured specimen, GSC 29511. 

Discussion.-The specimens are crushed and too 

poorly preserved for more exact identification. Superficially they appear to have some characteristics 

of H anaites but apparently are not reticulate. 

Occurrence.-Ludvigsen collection I-3 from the 

Michelle Formation, Hart River, Yukon Territory. 

Ostracode indet. 2 

Plate 14, figure 22 

Description.-Lateral outline semielliptical, amplete to postplete. Hinge line straight; anterior margin smoothly rounded ; ventral margin gently curved, 

swinging up into more acutely curved posterior margin. S1 shallow and poorly defined; S2 wide, somewhat deeper than S1, extending about half height of 

valve; weak S3 or hemisulcus in posterior quarter of 

valve. L1 broad, smoothly arched; L2 small, ovate, 

set below hinge line; L3 broad, slightly humped above 

hinge line; L4 smooth, sloping to posterior margin. 

Anterior end of valve with poorly defined velar bend 

which extends posteriorly to beneath L3 but merges 

with surface anterior to small posteroventral spine. 

Small anterodorsal spine above S2. Shell surface 

apparently smooth to very finely granulose. 

M aterial.-One left valve from the McCann Hill 

Chert. 

Measurements.-The figured specimen is 1.30 mm 

long and 0. 75 mm high. 

Types.-Figured specimen, USNM 173839. 

Discussion.-The anterior position of the weak 

velar bend, the small posteroventral spine and the 

humping of L3 above the hinge line suggest that this 

specimen may be an aberrant hollinid, but the weak 

sulcation and poorly developed velar structures are 

atypical of the Hollinacea. 

Occurrence.-VSGS collection 6492-SD from the 

McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. 

Ostracode indet. 3 

Plate 14, figures. 15, 16 

Description.-Carapace small, tumid, subovatetriangular in lateral view. Right valve overlapping 

left all around except dorsally. Hinge half greatest 

length, occupying middorsal area, incised between 

shoulders of both valves. Valves with narrow anterior and posteroventrally drawn-out flanges; more 

pronounced on right valve. Greatest height and 

width median; greatest length in ventral half. Surface somewhat granular, possibly with internal 

tubules. 

Mat erial.-Two specimens from the Prongs Creek 

Formation. 

Measurements.-The figured specimens are 0.60 

mm long, 0.35 mm high, and 0.40 mm wide. 

Types.-Figured specimens, GSC 29516, GSC 

29517. 

Discussion.-If these specimens are interpreted 

correctly, they possess right-over-left overlap. A reversal of overlap may exist with some pachydomellid 

genus, but this cannot be substantiated with the material at hand. These specimens are similar to the 

specimens from the McCann Hill Chert previously 

described as "pachydomellid, indet. 1" but differ in 

having the greatest thickness median rather than 

posterior and in having both anterior and posterior 

flanges. 

Occurrence.-Ludvigsen collection V -3 from the 

Prongs Creek Formation, Solo Creek, Yukon Territory. 
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Page 

A 

Abbreviations 8 ------------------------

Abditoloculina ------------------------- 7, 16 

binodata ------------------------- 16, 17 

claUBa ----------------------- 6, 16, pl. 6 

insolita --------------------------- 16 

sp -------------------------------

Abortivelum --------------------------

16 

19 

truncatum ------------------- 6, 19, pl. 6 

Acanthoscapha ----------------------- 81, 32 

navicula -------------------------- 32 

sp -------------------------- 6, 81, pl. 11 

Acknowledgments --------------------- 1 

acuminatum, lnfractivelum ___ 6, 21, 22, pl. 8 

Adelphobolbina --------------------- 7, 19, 21 

aliquanta -------------------- 6, 19, pl. 6 

bulbosa --------------------------- 20 

medialis ---------------------- 6, 20, pl. 7 

megalia -------------------------- 210 

papillata ------------------------- 20 

papillosa -------------------------- 20 

pinguis --------------------------- 20 

prongsensis ------------------ 6, 20. pl. 7 

spicata --------------------------- 20 

trilobata ------------------------- 20 

sp ---------------------------- 19, 20, 21 

Ages of formations ------------------- 4 

Alaskabolbina ------------------------- 14 

bilineata ------------------ 6, 14, 15, pl. 5 

nodilineata --------------- 6, 14, 15, pl. 5 

unilineata ----------------- 6, 14, 15, pl. 5 

sp --------------------------- 6, 15, pl. ·5 

alatus, Pseudocyproidea --------------- 33 

aliquanta, Adelphobolbina -------- 6, 19, pl. 6 

Allanella ----------------------------- 32 Altai-Sayan region, Siberia, U.S.S.R. __ 36 

antespinosa, Hollinella ---------------- 18, 19 

Aparchites --------------------------- 27, 28 

auriculiferus -------------- 6, 7, 28, pl. 10 

chuchlensis ----------------------- 29 

crossotUB ------------------------- 27 

whiteaveai ------------------------ 29 

Aparchitidae -------------------------- 27 

Apatobolbina ------------------------- 14 

arctigena, Beyrichia (Beyrichia) ------ 10 

Arcyzonidae -------------------------- 22 

argutula, Kno:x:ites -------------------- 15 

Ogilvites ------------------------- 16 

auriculiferua, Aparchites ------ 6, 7, 28, pl. 10 

B 

Bairdia --------------------------- 80, 31, 32 

dejecta ---------------------- 6, 80, pl. 11 

emaciata ------------------------- 30 

leguminoides ------------- 6, 90, 31, pl. 11 

mucronata ------------------------ 30 

navicula -------------------------- 31 

transversocostata ------------------ 31 

Bairdiidae ---------------------------- 90, 32 

Bairdiocyprididae --------------------- 95 

Bairdiocypris ------------------------- 95 

cordiformis --------------- 6, 7, 95, pl. 12 

sp -------------------------- 6, 85, pl. 12 

INDEX 

[Italic page numbers indicate major reference} 

Page 

Bairdiohealdites ----------------------- 86 

rozhdeatvenskayae ----------------- 36 

scapulatUB ------------------ 6, 96, pl. 12 

Bairdiolitea --------------------------- 91 

sohni ----------------------- 6, 91, pl. 11 

barathrota, Trypetera ----------------- 37 

Barychilina --------------------------- 86 

opisthorhysa ---------------------- 37 

sp -------------------------- 6, 96, pl. 19 

Barychilinidae ------------------------ 86 

Bashkiria, U.S.S.R. -------------- 7, 28, 29,35 

Beecherella --------------------------- 32, 99 

carinata -------------------------- 33 

sp -------------------------- 6, 88, pl. 11 

Beecherellidae ------------------------ 91, 32 

Bell Shale ---------------------------- 17,27 

BerouneUa ---------------------------- 84 

minuta --------------------- 6, 84, pl. 12 

Berounellidae ------------------------- 94 

Beyrichia ---------------------------- 10, 12 

(Beyrichia) ----------------------- 7,10 

a'l"ctigena --------------------- 10 

b'l"abbi ------------------- 6, 10, pl. 2 

sp. A ------------------------ 10 

sp. B ------------------------ 10 

(Scabribeyrichia) ------------------ 7, 10 

churkini ----------------- 6, 10, pl. 3 

foliosa ------------------------ 11 

sp --------------------------- 11 

(Beyrichia) arctigena, Beyrichia ----- 10 

brabbi, Beyrichia ------------- 6, 10, pl. 2 

sp. A, Beyrichia ----------------- 10 

sp. B, Beyrichia ----------------- 10 

Beyrichiidae 

Beyrichiinae --------- ___ --------------

Bibliography -------------------------

8, 9 

10 

41 

Bicornina ----------------------------- 84 

sp -------------------------- 6, 94, pl. 12 

bicornis, Ogilvites ---------------- 6, 15, pl. 6 

bilineata, Alaskabolbina -------- 6,14, 15, pl. 5 

binoda, Condracypris ------------------ 36 

binodata, Abolitoloculina -------------- 16, 17 

Biya beds, Bashkiria, U.S.S.R. ------- 28, 35 

Blackstone River ----------------- 1, 2, 3, 5, 8 

blackstonensis, Kuresaaria ------- 6, 85, pl. 12 

Blue Fiord Formation -------------- 5, 8, 30 

Bohemia ----------------------------- 5 

borealis, Treposella ---------------- 6, 9, pl. 1 

brabbi, Beyrichia (Beyrichia) ----- 6, 10, pl. 2 

brevis, Hanites ------------ 6, 24, 25, 26, pl. 9 

bulbosa, Adelphobolbina -------------- 20 

Bythocypris sp ----------------------- 35 

c 

Camden Chert 7 

camdenensis, Camdenidea ------------- 33 

Camdenidea ----- -------------------- 93 

camdenesis ----------------------- 33 

sp -------------------------- 6, 93, pl. 13 

Canadian Arctic Archipelago --------- 5 

carinata, Beecherella ----------------- 33 

caurina, Tricornina ------------- 6, 38, pl. 12 

Cavellina ----------------------------- 97 

(Invisibila) ---------------------- 97 

porrecta --------------------- 38 

sp ---------------------- 7, 97, pl. 14 

Celechovites 

Page 

32 

Chironiptrum ------------------------- 22 

limitaris --------------------- 6, 22, pl. 8 

oiostathmicum -------------------- 22, 23 

reticularis ---------------- 6, 22, 23, pl. 8 

sp --------------------------------

chuchlensis, Aparchites ---------------

churkini, Beyrichia 

22 

29 

(Scabribeyrichia) ---- 6, 10, pl. 3 

circulata, Libumella ------------- 6. 28, pl. 10 

claUBa, Abditoloculina ------------ 6, 16, pl. 6 

Clintiella ------------------------------ 9 

compressa, Hollina ------------------- 17 

Condracypris -------------------------- 36 

binoda ---------------------------- 36 

Contact, McCann Hill Chert-Road 

River Formation ---------- 2 

Michelle and Road River Formations 2 

Nation River Formation-McCann 

Hill Chert --------------- 3 

Ogilvie and Michelle Formations__ 3 

Prongs Creek and Road River 

Formations -------------- 3 

cordiformis, Bairdiocypris -------- 6, 95, pl. 12 

Correlation --------------------------- 4 

intercontinental 7 

Craspedobolbininae ------------------- 9 

Craterellina oblonga ------------------- 39 

crescentifera, Neocraterellina ---- 7, 99, pl. 14 

crossotus, Aparchites ----------------- 27 

Subarctichites --------------------- 27 

Ctenoloculinidae 

Ctenoloculininae ___ ---------------- __ _ 

Cypridinidae --------------------------

Cystomatochilina _ ------------------ __ _ 

D 

16 

16 

32 

14 

dalhousiensis, EukloedeneUa ----------- 29 

dejecta, Bairdia ----------------- 6, 90, pl. 11 

Devon Isliand, Canada ----------------- 5 

discoides, Libumella ----------- 6, 7, 27, pl. 10 

E 

Eag!e (D-1) quadrangle, Alaska ------ 3, 8 

eifeliensis, Obotritia ------------------ 23 

Ellesmere Island ------------------- 8, 20, 30 

Ellesmeria ---------------------------- 37 

ovata ----------------------------- 37 

emaciata, Bairdia -------------------- 30 

Eobeyrichia --------------------------- 11 

Eriella ------------------------------- 99 

robusta --------------------------- 39 

sp -------------------------- 7, 99, pl. 14 

Eukloedenella ----------------------··-- 29 

dalhousiensis --------------------- 29 

recta ----------------------- 6, 29, pl 11 

soloensis -------------------- 6, 29, pl. 11 

sulcifrons ------------------------- 29 

umbilicata ------------------------ 29 

sp -------------------------------- 29 

Eurekaspirifer pinyonensis Zone ------ 5 

Eu'l"ychilina mirabilis ------------------ 24, 25 

45 
46 

Page 

F 

Falls of the Ohio River 7 

FalsipoUe~ --------------------------- 7, 17 

multispinosus ----------------- 6, 1'!, pl. 7 

Falsipollicinae ------------------------ 1'! 

Flaccivelum ------------------------- 7, 9, 21 

informis -------------------------- 21 

teleutaea ------------------------- 21 

sp --------------------------- 6, ~1. pl. 8 foliosa, Beyrichia (Scabribeyrichia) ___ 11 

Fossil collections ----------------------3, 5, 8 

(Framella), Poloniella ---------------- 90 

scheii, PolonieUa ---------- 6, 8, 90, pl. 11 

G 

GarnieUa ----------------------------- 9 Gasterocoma bicaula _____________ _:____ 5 

Genshaw Formation ------------------ 17,20 

givetiana, Halliella (Hanaites) -------- 24 

Hanaites ------------------------- 25 

gotlandica, Kuresaaria ---------------- 35 

granosa, Parabolbina ----------------- 17 

Gravia ------------------------------- 27 

Guerichina strangulata Zone 5 

H 

HallieUa ------------------------------ 24 

(Hanaites) givetiana ------------- 24 

Hanaites ----------------------------- 24, 40 

brevis ----------------- 6, 24, 25, 26, pl. 9 

givetiana ------------------------- 25 

linearis --------------- 6, 24, 25, 26, pl. 9 

platus --------------------------- 25, 26 

spinosus ------------------ 6, 24, 25, pl. 9 

sp. A ---------------------------- 25 

sp. B ----------------------------- 25 

(Hanaites) givetiana, Halliella ------- 24 

Hart River ------------------------ 1, 2, 3, 8 

hartleyi, Mesomphalus ----------------- 9 

Harz region, Germany ---------------- 5 

Healdia ------------------------------- 39 

sp ------------------------------- 39 

Heteromorph, defined ----------------- 18 

Hillard Peak ------------------------- 1, 8 

Hollina ------------------------------ 7,1'! 

compressa ------------------------ 17 

insolens -------------------------- 17 

py~idata ------------------------- 17 

sp --------------------------- 6, 1'!, pl. 6 

Hollinella -------------------------- 7,18, 21 

antespinosa ---------------------- 18, 19 

ludvigseni ------------------- 6, 18, pl. 7 

paucituberculata -------------- 6, 18, pl. 7 

plauta ---------------------------- 18 

(Praehollinella) ------------------ 18, 21 

pumila --------------------------- 18 

sella ------------------------------ 19 

senticosa ------------------------- 18 

sp ------------------------------- 18,22 

Hollinellidae -------------------------- 18 

Hollinidae ---------------------------- 1'!, 24 

Hollininae ---------------------------- 1'! 

hypercala, Parabolbina ---------------- 17 

I 

informis, Flaccivelum ----------------- 21 

lnfractivelum ------------··----------- 21 

acuminatum --------------- 6, 21, 22, pl. 8 

spiculosum ---------------- 6, 21, 22, pl. 8 

insericus, Neoaparchites ---------- 6, 28, pl. 10 

Punctaparchites ------------------ 28 

insolens, Hollina ---------------------- 17 

INDEX 

Page 

insolita, Abditoloculina --------------- 16 

inventa, Voronina ------------- 6, 7, 97, pl. 13 

(lnvisibila), Cavellina --------------- 9'! 

porrecta, Cavellina ---------------- 38 

sp., Cavellina --------------- 7, 97, pl. 14 

J 

Jeffersonville, Ind -------------------- 7 

Jeffersonville Limestone -------------- 7, 20 

Jordanites --------------------------- 18, 21 

K 

Kalkberg Limestone ------------------ 32 

Kirkbyella ---------------------------- f4 

(Kirkbyella) --------------------- 24 

sp ----------------------- 6, f4, pl. 9 

(Kirkbyella), Kirkbyella -------------- 24 

sp., Kirkbyella ---------------- 6, 24, pl. 9 

Kirkbyellidae ------------------------- 24 

Kloedenellidae 

Kno~ites argutula -------------------

Koneprusia subterarmata --------------

sp -------------------------------

Krekov beds, Salair district, Siberia, 

U.S.S.R. ------------------

29 

15 

5 

5 

36 

Kuresaaria --------------------------- 95 

blackstonensis --------------- 6, 95, pl. 12 

gotlandica ------------------------ 35 

L 

leguminoides, Bairdia -------- 6, 90, 31, pl. 11 

Leptobolbina -------------------------- 14 

Libumella ----------------------------- 27 

circulata -------------------- 6, 28, pl. 10 

discoides ------------------ 6, 7, 27, pl. 10 

sp ------------------------------- 27 

limitaris, Chironiptrum ----------- 6, 22, pl. 8 

linearis, Hanaites -------- 6, 24, 25, 26, pl. 9 

Localities ---------------------------- 8 

Louisville, Ky ------------------··----- 7 

ludvigseni, Hollinella ------------- 6, 18, pl. 7 

lyoni, Treposella -------------- 6, 9, 10, pl. 1 

M 

McCann Hill Chert -------------------- 2 

collection localites ---------------- 8 

fauna ---------------------------- 4 

lithology ------··------------------- 3 

medialis, Adelphobolbina ---------- 6, 20, pl. 7 

megalia, Adelphobolbina -------------- 20 

Mesomphalus ------------------------- 7, 9 

hartleyi -------------------------- 9 

sp ---------------------------- 6, 9, pl. 1 

Michelle Formation ------------------- 2 

collection localites ---------------- 8 

fauna ---------------------------- 5 

lithology -------------------------- 3 

Microcheilinella ----------------------- 99 

sp -------------------------- 7, 99, pl. 14 

Migration routes --------------------- 1 

minuta, Berounella ------------- 6, 94, pl. 12 

mirabilis, Eurychilina ----------------- 24, 25 

Monograptus yukonensis -------------- 2, 8 

mucronata, Bairdia -------------------- 30 

multispinosus, Falsipolle~ -------- 6, 17, pl. 7 

N 

Nation River Formation 3 

navicula, Acanthoscapha -------------- 32 

Bairdia ------------------------··-- 31 

Neoaparchites ------------------------ 28 

Page 

insericus ------------------ 6, 7, 28, pl. 10 

obsoletus ------------------------- 28 

Neocraterellina ----------------------- 99 

crescentifera ---------------- 7, 39, pl. 14 

Newsomites ------------------------ 7, 31, 38 

notabilis -------------------------- 38 

pertumidus ----------------------- 31, 38 

profusus ------------------------- 31, 38 

sp -------------------------- 6, 91, pl. 14 

NodeUa --------------------··---------- 24 

Nodellidae --------------------------- 24 

nodilineata, Alaskabolbina ----- 6, 14, 15, pl. 5 

notabilis, Newsomites ------------------ 38 

Novgorod district, U.S.S.R. ----------- 16 

Nowakia barrandei ------------------ 4 

parabarrandei -------------------- 5 

0 

oblonga, Craterellina ----------------- 39 

Obotritia ----------------------------- 29 

eifeliensis ------------------------ 23 

sp --------------------------- 6, 29, pl. 8 

obsoletus, Neoaparchites -------------- 28 

Primitia -------------------------- 28 

Ogilvie Formation -------------------- 3, 5 

Ogilvites ------------------------------ 15 

argutula -------------------------·· 16 

bicornis ---------------------- 6, 15, pl. 6 

oiostathmicum, Chironiptrum --------- 22, 23 

opisthorhysa, Barychilina -------------- 37 

orthoclefta, Thlipsurella -------------- 39 

Ostracode collections ----------------- 5, 8 

Ostracode indet. 1 -------------- 7, 40, pl. 14 

indet. 2 -------------------- 7, 40, pl. 14 

indet. 3 -------------------- 7, 40, pl. 14 

Ostthuringer, Germany --------------- 7 

ovata, Ellesmeria --------------------- 37 

p 

Pachydomellid indet. --------- 7, 98, pl. 14 

indet. 2 --------------------- 7, 98, pl. 14 

Pachydomellidae ---------------------- 98 

papillata, Adelphobolbina ------------- 20 

papillosa, Adelphobolbina ------------- 20 

Parabolbina --------------------------- 7, 17 

granosa -------------------------- 17 

hypercala ------------------------- 17 

pulchella ------------------------- 17 

sp --------------------------- 6, 17, pl. 8 

Parabolbininae ------------------------ 17 

Paraparchitidiae ----------------------- 28 

Paraspirifer acuminatus Zone --------- 7 

paucituberculata, Hollinella ------ 6, 18, pl. 7 

pertumidus, Newsomites --------------- 31,38 

Phlyctiscapha ------------------------- 27 

pinguis, Adelphobolbina -------------- 20 

platum, Proplectrum ----------------- 24 

platus, Hanaites ---------------------- 25,26 

plauta, Hollinella --------------------- 18 

Plum Brook Formation --------------- 39 

Poloniella ---------------------------- 90 

(Framella) ----------------------- 30 

scheii -------------------- 6, 8, 90, pl. 11 

Polygnathus dehiscens ---------------- 5 

foveolatus ------------------------- 5 

lenzi ----------------------------- 5 

Porcupine River ---------------------- 4 

porrecta, Cavellina (lnvisibila) 38 

(Praehollinella), Hollinella ----------- 18, 21 

praepilata praepilata, Praepilatina ----- 36 

sibirica, Praeplatina ------ 6, 8, 36, pl. 13 

P'f'aepilatina -------------------------- 36 

praepilata praepilata -------------~ 36 

praepilata sibirica --------- 6, 8, 36, pl. 13 

Primitia obsoletus -------------------- 28 
Page 

profusus, Newsomites ----------------- 31, 38 

Prongs Creek Formation -------------- 2 

collection localities --------------- 8 

lithology ------------------------- 3 

prongsensis, Adelphobolbina ------- 6, 20, pl. 7 

Proplectrum platum ------------------ 24 

Pseudocyproides ----------------------- 33 

alatus ---------------------------- 33 

pulchella, Parabolbina ---------------- 17 

pumila, Hollinella -------------------- 18 

Punctaparchites ----------------------- 28 

insericus ------------------------- 28 

rugosa --------------------------- 28 

py:~:idata, Hollina --------------------- 17 

Q 

Quasillitidae 99 

R 

recta. EukloedeneUa ------------ 6, 29, pl. 11 

Rectobairdia -------------------------- 91 

sp -------------------------- 6, 91, pl. 11 

Regional relationships ---------------- 3 

reticularis, Chironiptrum ------ 6, 22, 23, pl. 8 

Rheinische Schiefergebirge, Germany___ 7 

Richardson Mountains ---------------- 1 

Road River Formation --------------- 2 

robusta, ErieUa ------------------------ 39 

rozhdestvenskayae, Bairdiohealdites ___ 36 

rugosa, Punctaparchites -------------- 28 

Ruptivelum --------------------------- 21 

s 

Saccarchites sp ----------------------- 27 

Salair district, Siberia ---------------- 8 

Salmontrout Limestone --------------- 4 

Salmontrout River ------------------- 4 

(Scarbribeyrichia), Beyrichia --------- 7, 10 

churkini, Beyrichia ----------- 6, 10, pl. 3 

!oliosa, Beyrichia ----------------- 11 

sp., Beyrichia -------------------- 11 

INDEX 

Page 

Scaphina ----------------------------- 32 

scapulatus, Bairdiohealdites ------ 6, 96, pl. 13 

scheii, Poloniella (Framella) __ 6, 8, 30, pl. 11 

Schoharie Formation ----------------- 7 

SchoharieUa -------------------------- 14 

Sedimentation ------------------------ 2 

sella, HollineUa ----------------------- 19 

senticosa, HollineUa ------------------ 18 

serratulus, Subartichites ---------- 6, 27, pl. 9 

Shidelerites --------------------------- 7, 32 

typus ----------------- ---- 32, 33, pl. 11 

yukonensis ------------------ 6, 32, pl: 11 

Shriver Chert ------------------------- 39 

sibirica, Praepilatina praepilata_ 6, 8, 36, pl. 13 

sohni, Bairdiolites --------------- 6, 91, pl. 11 

Solo Creek ----·---------------------- 1, 3, 5 

solo, Yukonibeyrichia ---------- 6, 11, 19, pl. 4 

soloensis, Eukloedenella ---------- 6, 29, pl. 11 

spicata, Adelphobolbina --------------- 20 

spiculosum, lnfractivelum ----- 6, 21, 22, pl. 8 

spinosus, Hanaites ----------- 6, 24, 25, pl. 9 

Stratigraphy ------------------------- 2 

steUata, TreposeUa ------------------- 9 

Subarctichites ------------------------- 27 

crossotus ------------------------- 27 

serratulus -------------------- 6, 27, pl. 9 

sulci/rona, Eukloedenella -------------- 29 

T 

Tecnomorph, defined ------------------ 18 

Teicherticeras lenzi ------------------- 5 

teleutaea, Flaccivelum ---------------- 21 

Terminology -------------------------- 8 

Tetracornella ------------------------- 24 

Thlipsurella orthoclefta ---------------- 39 

Thlipsuridae -------------------------- 99 

Trail River --------------------------- 3 

tranB'/Jersocostata, Bairdia ------------ 31 

TreposeUa ---------------------------- 7, 9 

borealis ----------------------- 6, 9, pl. 1 

lyoni ----------------------- 6, 9, 10, pl. 1 

steUata --------------------------- 9 

sp ------------------------------- 9 

47 

Page 

Treposellinae ------------------------- 9 

Tricornina --------------------------- 39, 34 

caurina --------------------- 6, 33, pl. 11 

sp -------------------------- 6, 94, pl. 12 

Tricorninidae ------------------------- 93 

trilobata, Adelphobolbina -------------- 20 

truncatum, Abortivelum ---------- 6, 19, pl. 6 

Trypetera ---------------------------- 97 

barathrota ------------------------ 37 

sp -------------------------- 6, 97, pl. 14 

Tubulibairdia ------------------------- 98, 39 

sp -------------------------- 7, 38, pl. 14 

Turkestanella acuaria ----------------- 5 

typus, Shidelerites ------------- 32, 33, pl. 11 

u 

umbilicata, Eukloedenella 29 

unilineata, Alaskabolbina ------ 6, 14, 15, pl. 5 

Ural Mountains -------------------- 7, 28, 29 

v 

voronensis, Voronina ----------------- 37 

Voronina ----------------------------- 37 

inventa -------------------- 6,7, 97, pl. 13 

voronensis ------------------------ 37 

w 

Waldron Shale 

whiteavesi, Aparchites ----------------

Windom Member, Moscow Shale ------

y 

Yukon Shelf 

32 

29 

21 

yukonensis, Monograptus -------------- 8 

Shidelerites ----------------- 6, 92, pl. 11 

Yukonibeyrichia ------- 6, 11, 12, 13, pl. 4 

Yukonibeyrichia ---'-"'----------------- 11 

solo ----------------------- 6, 11, 19, pl. 4 

yukonensis ------------- 6, 11, 12, 13, pl. 4 

PLATES 1-14 
PLATE 1 

[All figures X 30] 

FIGURES 1, 2. Mesomphalus? sp. (p. 9). 

Broken tecnomorphic right and left valves from the Prongs Creek Formation, Ludvigsen collection V -3. 

Figured specimens, GSC 29439, 29438. 

3, 4. Treposella sp. cf. T. lyoni (Ulrich, 1891) (p. 9). 

Immature tecnomorphic right and left valves from the McCann Hill Chert, USGS collection 7037-SD. 

Figured specimens, USNM 173728, 173729. 

5-10. Treposella borealis n. sp. ( p. 9). 

5. Small tecnomorphic left valve from the McCann Hill Chert, USGS collection 6492-SD. Paratype, 

USNM 170351. 

6. Tecnomorphic right valve from the Prongs Creek Formation, Ludvigsen collection V -3. Para type, 

GSC 29453. 

7. Ventral view of holotype, USNM 170352, showing the treposelline bridges across the ventral surface of the crumina. McCann Hill Chert, USGS collection 649·2-SD. 

8. Lateral view of heteromorphic right valve, holotype, USNM 170352. 

9. Interior view of a heteromorphic left valve from the McCann Hill Che·rt, USGS collection 7032-SD, 

showing the s·trut across the crumina. Paratype, USNM 173731. 

10. Large tecnomorphic right valve from the McCann Hill Chert, USGS collection 6492-SD. Paratype, 

USNM 173730. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE I 

MESOMPHALUS? AND TREPOSELLA 
PLATE 2 

FIGURES 1-8. Beyrichia (Beyrichia) brabbi n. sp., X 30 (p. 10). 

1. Small tecnomorphic left valve, paratype, GSC 29474, from the Prongs Creek Formation, Ludvigsen 

collection V -3. 

2. Small tecnomorphic right valve, paratype, USNM 173732, from the McCann Hill Chert, USGS collection 6492-SD. 

3. Tecnomorphic left valve, paratype, USNM 173733, from the McCann Hill Chert, USGS collection 

6492-SD. 

4. Tecnomorphic left valve, paratype, GSC 29473, from the Prongs Creek Formation, Ludvigsen collection V- 3. 

5. Ventral view of heteromorphic right valve, paratype, USNM 173734, from the McCann Hill Chert, 

USGS collection 6492- SD. 

6. Large tecnomorphic right valve, paratype, USNM 170347, from the McCann Hill Chert, USGS collection 6492-SD. 

7. Heteromorphic right valve, holotype, USNM 170346, from the McCann Hill Chert, USGS collection 

6492-SD. 

8. Heteromorphic left valve, paratype, USNM 173736, from the McCann Hill Chert, USGS collection 

6492-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 2 

BEYRICHIA (BEYRICHIA) 
PLATE 3 

FIGURES 1-9. Beyrichia (Scabribeyrichia) churkini n. sp., X30 (p. 10). 

1. Small tecnomorphic right valve, paratype, USNM 173737, from the McCann Hill Chert, USGS collection 6492-SD. 

2. Small tecnomorphic left valve, paratype, USNM 173738, from the McCann Hill Chert, USGS collection 6492-SD, showing four spines fusing to form calcarine spine. 

3, 4. Tecnomorphic right valves, paratypes, GSC 29472, 29471, from the Prongs Creek Formation, Ludvigsen collection V -3. 

5. Large tecnomorphic left valve, paratype, USNM 170348, from the McCann Hill Chert, USGS collection 6492- SD, showing unusually well developed fissus. 

6, 7. Ventral and lateral views of heteromorphic right valve, holotype, USNM 170349, from the McCann 

Hill Chert, USGS collection 6492-SD. 

8. Tecnomorphic left valve, paratype, GSC 29470, from the Prongs Creek Formation, Ludvigsen collection V-5. 

9. Heteromorphic left valve, paratype, GSC 29469, from the Prongs Creek Formation, Ludvigsen collection V -3 . 
GEOLOGICAL SURVEY PROFESSIONAL PAPER R25 PLATE 3 

BEYRICHIA (SCABRIBEYRICHIA) 
PLATE 4 

[All figures X 30] 

FIGURES 1-4. Yukonibeyrichia solon. sp. (p. 13). 

1. Tecnomorphic left valve, paratype, GSC 29436, from the Prongs Creek Formation, Ludvigsen 

collect~on V -3. 

2. Tecnomorphic right valve, holotype, GSC 29435, from the Prongs Creek Formation, Ludvigsen 

collection V-3. 

3, 4. Heteromorphic left valve, lateral and ventral views, para type, GSC 29437, from the Prongs Creek 

Formation, Ludvigsen collection V -4. 

5-11. Yukonibeyrichia yukonensis n. gen., n. sp. (p. 12). 

5, 6. Broken heteromorphic right valve, lateral and ventral views, paratype, USNM 173740, from the 

McCann Hill Chert, USGS collection 7032-SD. 

7. Small tecnomorphic right valve, paratype, GSC 29434, from the Prongs Creek Formation, Ludvigsen collection V -3. 

8. Small tecnomorphic right valve, paratype, USNM 173741, from the McGann Hill Chert, USGS 

collection 7032-SD. 

9. Small tecnomorphic left valve, paratype, USNM 170345, from the McCann Hill Chert, USGS collection 6492-SD. 

10. Tecnomorphic left valve, holotype, GSC 29432, from the Prongs Creek Formation, Ludvigsen collection V -3. 

11. Heteromorphic left valve, paratype, GSC 29433, from the Prongs Creek Formation, Ludvigsen 

collection V -3. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 4 

YUKONIBEYRJCHJA 
PLATE 5 

[All figures X 30] 

FIGURES 1-6. Alaskabolbina nodilineata n. sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p. 14). 

1. Lateral view of heteromorphic? right valve, holotype, GSC 29512. 

2. Interior of holotype showing possible cruminal structure. 

3. Ventral view of holotype showing double row of subvelar tubercles. 

4-6. Lateral, interior, and dorsal views of heteromorphic? left valve, paratype, GSC 29513. 

7-10. Alaskabolbina? sp., from the McCann Hill Chert, USGS collection 7037-SD (p. 15). 

7. Small right valve, figured specimen, USNM 173840. 

8. Small left valve, figured specimen USNM 173841. 

9. Larger broken right valve, figured specimen, USNM 173842, showing more extended velum. 

10. Small papillose right valve, figured specimen, USNM 173843, lacking dorsal cusps. 

11, 12. Alaskabolbina sp. (p. 15). 

11. Small immature right valve, figured specimen, USNM 173844, from the McCann Hill Chert, USGS 

collection 7037-SD, showing dorsal cusps. 

12. Immature left valve, figured specimen, USNM 173845, from the McGann Hill Chert, USGS collection 7037-SD. Possibly juvenile form of Alaskabolbina nodilineata, n. sp. 

13-15. Alaskabolbina uniz.ineata n. gen., n. sp. (p. 14). 

13. Right valve, holotype, USNM 173745, from the McCann Hill Chert, USGS collection 6492-SD. 

14. Ventral view of holotype showing single toric ridge. 

15. Dorsal view of holotype. 

16-21. Alaskabolbina bilineata n. sp., from the Michelle Formation, Ludvigsen collection II- 11 (p. 14). 

16. Broken left valve, paratype, GSC 29465, showing dorsal tubercles. 

17. Broken left valve, paratype, GSC 29467. 

18. Broken right valve, paratype, GSC 29468. 

19. Broken right valve, paratype, GSC 29466. 

20. Left valve, holotype, GSC 29464. 

21. Ventral view of holotype showing double toric ridges. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 5 

ALASKABOLBINA AND ALASKABOLBINA? 
FIGURE 

PLATE 6 

[All figures X 30] 

1. Ogilvites bicornis n. sp. (p. 15). 

Left ( ?) lateral view of holotype, GSC 29454, from the Prongs Creek Formation, Ludvigsen collection 

V-3. 

2-8. Abditoloculina clausa n. sp., from the McCann Hill Chert (p. 16). 

2-4. Left-lateral, right-lateral, and ventral views of the holotype, U SNM 170338, a heteromorphic 

carapace, USGS 'collection 6492-SJ?. Figure 4 shows the closed loculi characteristic of the 

species. 

5, 6. Ventral and left-lateral views of a tecnomorphic carapace, paratype, USNM 173746, USGS collection 6492-SD. 

7, 8. Exterior and interior views of a heteromorphic left valve, paratype, USNM 173747, showing 

loculi, USGS collection 7033-SD. 

9. Abditoloculina clausa? (p. 16). 

Lateral view of an immature tecnomorphic right valve from the McCann Hill Chert, USGS collection 

7033-SD. Figured specimen, USNM 173750. 

10-16. Abortivelum trunc.atum n. gen., n. sp., from the McCann Hill Chert, USGS collection 7032-SD (p. 19). 

10, 11. Right-lateral and ventral views of a heteromorphic carapace, paratype, USNM 173751. 

12-14. Right-lateral, ventral, and dorsal views of a tecnomorphic carapace, paratype, USNM 173753. 

15, 16. Exterior and interior views of a heteromorphic left valve, the holotype, USNM 173752. 

17-22. Adelphobolbina aliquanta n. sp. (p. 19). 

17. Immature tecnomorphic right val right valve, paratype, USNM 170341, from the McCann Hill 

USGS collection 6492-SD. 

18. Lateral view of a tecnomorphic right valve, para type, USNM 170341, from the McCann Hill 

Ohert, USGS collection 6492-SD. This specimen was originally thought to be a heteromorph. 

19. Tecnomorphic left valve, paratype, USNM 173756, from the McCann Hill Chert, USGS collection 6492-SD, showing anterodorsal cusp. 

20, 21. Exterior and interior views of a heteromorphic right valve, the holotype, USNM 173755, from 

the McCann Hill Chert, USGS collection 6492-SD, showing the character of the velum. 

22. Tecnomorphic left valve from the Michelle Formation, Ludvigsen collection Il-13, paratype, 

GSC 29497. 

23. Hollina sp. (p. 17). 

Tecnomorphic right valve, figured specimen, GSC 29441, from the Prongs Creek Formation, Ludvigsen 

collection V -3. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 6 

OGIL VITES, ABDITOLOCULINA, ABORT/VELUM, ADELPHOBOLBINA, AND HOLLINA 
FIGURES 

PLATE 7 

[All figures X 30] 

1-3. Hollinella ludvigseni n. sp. (p. 18). 

1. Tecnomorphic right valve, paratype, USNM 173764, from the McCann Hill Chert, USGS collection 6492-SD. 

2. Tecnomorphic right valve, holotype, GSG 29462, from the Prongs Creek Formation, Ludvigsen collection V -3. 

3. Heteromorphic right valve, paratype, GSC 29463, from the Prongs Creek Formation, Ludvigsen 

collection V -3. 

4, 5. Adelphobolbina sp. cf. A. medialis Stover, 1956 (p. 20). Technomorphic left and right valse, figured specimens, USNM 173759, 173760, from the McCann Hill Chert, USGS collection 6492-SD. 

S-8. Hollinella paucituberculata n. sp., from the Michelle Formation, Ludvigsen collection II-13 (p. 18). 

6. Heteromorphic right valve, paratype, GSC 29495. 

7. Tecnomorphic left valve, paratype, GSC 29496. 

8. Heteromorphic left valve, holotype, GSC 29494. 

9-13. Adelphobolbina prongsensis n. sp., from the Prongs Creek Formation (p. 20). 

9. Tecnomorphic left valve, paratype, GSC 29501, Ludvigsen collection V-3. 

10. Tecnomorphic left valve, paratype, GSC 29502, Ludvigsen collection V-4, showing papillose posterior. 

11. Heteromorphic right valve, holotype, GSC 29498, Ludvigsen collection V-3. 

12. Heteromorphic left valve, paratype, GSC 29,500, Ludvigsen collection V-3. 

13. Heteromorphic left valve, paratype, GSC 29499, Ludvigsen collection V-3. 

14-16. Falsipollex? multispinosus n. sp. (p. 17). 

14. Broken tecnomorphic left valve, paratype, USNM 173762, from the McCann Hill Chert, USGS 

collection 6492-SD. 

15. Heteromorphic right valve, holotype, USNM 173761, from the McCann Rill Chert, USGS collection 7032-SD. 

16. Interior of holotype showing dolonal pouch. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 7 

HOLL/NELLA, ADELPHOBOLBINA, AND FALSIPOLLEX? 
FIGURE 

PLATE 8 

[All figures X 30 except as noted] 

1. Obotritia? sp. (p. 23). 

Left valve, figured specimen, USNM 173774, from the McGann Hill Chert, USGS collection, 7037-SD. 

2-8. Ckironiptrum limitaris n. sp., (p. 22). 

2. Left-lateral view of carapace, paratype, USNM 173769, from the McCann Hill Chert, USGS collection 6492-SD. 

3, 4. Right-lateral and left-lateral views of carapace, paratype, USNM 170337, from the McCann Hill 

Chert, USGS collection 6492-SD. 

5. Right valve, paratype, GSC 29455, from the Prongs Creek Formation, Ludvigsen collection V -3. 

6, 7. Left-lateral and dorsal views of carapace, holotype, USNM 173770, from the McGann Hill 

Chert, USGS collection 7033-SD. 

8. Right valve, paratype, USNM 173771, from the McCann Hill Chert, USGS collection 6492-SD. 

9-14. Ckironiptrum reticularis n. sp., from the Michelle Formation (p. 22). 

9. Left valve, paratype, GSC 29459, Ludvigsen collection II-13. 

10. Dorsal view of carapace, paratype, GSC 29461, Ludvigsen collection II-10. 

11. Ventral view of carapace, paratype, GSG 29460, Ludvigsen collection II-10. 

12. Left-lateral view of carapace, paratype, GSC 29458, Ludvigsen collection Il-10. 

13. Left-lateral view of carapace, paratype, GSC 29457, Ludvigsen oollection 11-10. 

14. Right valve, holotype, GSC 29456, Ludvigsen collection 11-10. 

15, 16. Flaccivelum sp., (p. 21). 

Right valve, lateral aru:l ventral views, figured specimen, GSC 29509, from the Michelle Formation, 

Ludvigsen collection II-10. 

17, 18. Parabolbina sp., X 40 (p. 17). 

Ventral and left-lateral views of a carapace, figured specimen, GS.C 29449, from the Michelle Formation, Ludvigsen collection Il-10. 

19--23. lnfractivelum acuminatum n. gen., n. sp., from the Prongs Creek Formation (p. 21). 

19. Tecnomorphic left valve, paratype, GSC 29506, Ludvigsen collection V-3. 

20. Small tecnomorphic left valve, paratype, GSC 29507, Ludvigsen collection V-3. 

21. Heteromorphic right valve, holotype, GSC 29503, Ludvigsen collection V-3. 

22. Tecnomorphic right valve, para type, GSC 29505, Ludvigsen collection V-4. 

23. Heteromorphic right valve: paratype, GSC 29504, Ludvigsen collection V-3. 

24-27. lnfractivel?~m spiculosum n. sp., from the McCann Hill Chert (p. 22). 

24. Tecnomorphic right valve, paratype, USNM 173766, USGS collection 7033-SD. 

25. T~nomorphic left valve, pratype, USNM 173765, USGS collection 7033-SD. 

26. Tecnomorphic left valve, paratype, USNM 173767, USGS collection 6492-SD. 

27. Heteromorphic left valve, holotype, USNM 107342, USGS colleotion 6492-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 8 

OBOTRITIA? , CHIRONIPTRUM, FLACCIVELUM, PARABOLBINA, AND INFRACT/VELUM 
PLATE 9 

[All figures X 30] 

FIGURE 1. Kirkbyella (Kirkbyella) sp. (p. 24). 

Left valve, figured specimen, USNM 173775, from the McCann Hill Chert, USGS collection 7037-SD. 

2, 3. Hanaites linearis n. sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p. 24). 

2. Tecnomorphic left valve, paratype, GSC 29477. 

3. Heteromorphic right valve, holotype, GSC 29478. 

4-9. Hanaites brevis n. sp., from the McCann Hill Chert, USGS collection 6492-SD (p. 25). 

4. Tecnomorphic right valve, paratype, USNM 173776. 

5. Left-lateral view of small tecnomorphic carapace, paratype, USNM 173778. 

6. Tecnomorphic left valve, paratype, U SNM 170340. 

7-9. Right-lateral, dorsal, and ventral views of heteromorphic carapace, holotype, USNM 173777. 

10-15. Hanaites spinosus n. sp. (p. 25). 

10. Small tecnomorphic right valve, paratype, USNM 173781, from the McCann Hill Chert, USGS collection 7033-SD. 

11. Right-lateral view of heteromorphic carapace, paratype USNM 173782, from the McCann Hill Chert, 

USGS collection 6492-SD. 

12. Dorsal view of heteromorphic carapace, paratype, USNM 173783, from the McCann Hill Chert, 

USGS collection 6492-SD. 

13. Heteromorphic left valve, holotype, USNM 173780, from the McCann Hill Chert, USGS collection 

6492-SD. 

14. Tecnomorphic left valve, paratype, GSC 29479, from the Michelle Formation, Ludvigsen collection 

II-10. 

15. Tecnomorphic left valve, para type, U SNM 170339, from the McCann Hill Chert, USGS collection 

6492-SD. 

16-24. Subarctichites serratulus n. sp. (p. 27). 

16. Right-lateral view of holotype, USNM 173784, from the McCann Hill Chert, USGS collection 6492-

SD. 

17. Dorsal view of holotype. 

18. Ventral view of holotype showing rows of spinules. 

19. Interior of broken carapace, paratype, USNM 173785, from the McCann Hill Chert, USGS collection 

6492-SD, showing thin walls and narrow duplicature. 

20. Left valve, paratype, USNM 170350, from the McCann Hill Chert, USGS collection 6492-SD. 

21. Interior of left valve, para:type, GSC 29483, from the Prongs Creek Formation, Ludvigsen collection V-4. 

22. Right valve, paratype, GSC 29486, from the Prongs Creek Formation, Ludvigsen collection V- 3. 

23. Interior of left valve, paratype, GSC 29484, from the Prongs Creek Formation, Ludvigsen collection V-3. 

24. Interior of right valve, paratype, GSC 29485, from the Prongs Creek Formation, Ludvigsen collection V-3. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 9 

KIRKBYELLA , HANAITES, AND SUBARCTJCHITES 
FIGURES 

PLATE 10 

[AU figures X 30] 

1-5. Libumella sp. cf. L. discoides Rozhdestvenskaya, 1959 (p. 27). 

1. Lateral view of carapace, figured specimen, GSC 29480, from the Prongs Creek Formation, 

Ludvigsen collection V-3. 

2. Lateral view of carapace, figured specimen, GSC 29481, from the Prongs Creek Formation, Ludvigsen collection V - 3. 

3. Lateral view of carapace, figured specimen, USNM 170344, from the McCann Hill Chert, USGS 

collection 6492-SD. 

4, 5. Lateral and dorsal views of larger carapace, figured specimen, USNM 173789, from the McCann 

Hill Chert, USGS collection 7032- SD. 

6-8. Libumella sp. cf. L. circulata Rozhdestvenskaya, 1962 (p. 28). 

6. Right valve, figured specimen, GSC 29482, from the Prongs Creek Formation, Ludvigsen collection 

V-3. 

7, 8. Left valve, exterior and interior views, figured specimen, USNM 173790, from the McCann Hill 

Chert, USGS collection 7032-SD. 

9-12. Neoaparachites? sp. aff. N.? insericus (Rozhdestvenskaya, 1962) (p. 28). 

9, 10. Right valve, exterior and interior views, figured specimen, USNM 173791, from the McCann Hill 

Chert, USGS collection 6492-SD. 

11, 12. Right-lateral and dorsal views of carapace, figured specimen, USNM 173792, from the McCann 

Hill Chert, USGS collection 7032 - SD. 

13, 14. "Aparchites" sp. aff. 'A." auriculiferus Rozhdestvenskaya, 1962 (p. 28). 

Lateral and dorsal views of broken carapace, figured specimen, USNM 173793, from the McCann Hill 

Chert, USGS collection 7932-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 10 

LIBUMELLA, NEOAPARCHITES?, AND "APARCHJTES" 
PLATE 11 

[All figures X 30] 

FIGURES 1-4. Bairdia dejecta n. sp. (p. 30). 

1. Right-lateral view of incomplete carapace, paratype, USNM 173801, from the McCann Hill 

Chert, USGS collection 7037-SD. 

2-4. Right-lateral, left-lateral, and dorsal views of holotype, USNM 173800, from the McCann Hill 

Chert, USGS collection 7037-SD. 

5, 6, 9. Bairdiolites? sohni n. sp. (p. 31). 

5, 6. Right-lateral and dorsal views of holotype, USNM 173803, from the McCann Hill Chert, USGS 

collection 7037-SD. 

9. Interior of right valve, paratype, USNM 173804, from the McCann Hill Chert, USGS collection 7037-SD. 

7, 8. Beecherella? sp. (p. 33). 

Dorsal and lateral views of right valve, figured specimen, USNM 173808, from the McCann Hill 

Chert, USGS collection 7037-SD. 

10, 11. Bairdia sp. cf. B. leguminoides Ulrich, 1891 (p. 30). 

10. Right-lateral view of carapace, figured specimen, GSC 29508, from the Prongs Creek Formation 

Ludvigsen collection V-5. 

11. Left valve, figured &pecimen, USNM 173799, from the McCann Hill Chert, USGS collection 7038--

SD. 

12-14. Acanthoscapha sp. (p. 31). 

Right-lateral, left-lateral, and dorsal views of poorly preserved carapace, figured specimen, USNM 

173807, from the McCann Hill Chert, USGS collection 7037-SD. 

15. Rectobairdia sp. ( p. 31). 

Left valve, figured specimen, USNM 173802, from the McCann Hill Chert, USGS collection 6492-SD. 

16, 17. Shidelerites typus Morris and Hill, 1951 (p. 32). 

16. Right-lateral view of holotype, USNM 116420, from the Waldron Shale of Indiana. 

17. Right-lateral view of para type, U SNM 116421a, showing anterior spine. 

18. Shidelerites yukonensis n. sp. ( p. 32). 

Right-lateral view of carapace, holotype, GSG 29440, from the Prongs Creek Formation, Ludvigsen 

collection V-3. 

19-24. Eukloedenella recta n. sp. (p. 29). 

19, 20. Left-lateral and dorsal views of carapace, paratype, USNM 173794, from the McCann Hill 

Chert, USGS collection 7037-SD. 

21. Left-lateral view of carapace, paratype, GSC 29445, from the Michelle Formation, Ludvigsen 

collection 11-10. 

22. Right valve, paratype, GSC 29446, from the Michelle Formation, Ludvigsen collection 11-11. 

23. Right valve, holotype, GSC 29443, from the Michelle Formation, Ludvigsen collection 11-10. 

24. Dorsal view of carapace, paratype, GSC 29444, from the Michelle Formation, Ludvigsen collection 11-10. 

25--27. Poloniella (Framella) sp. aff. P. (F.) scheii Weyant, 1968, from the McCann Hill Chert, USGS collection 

7037-SD (p. 30). 

25. Left valve, figured specimen, USNM 173796. 

26. Left valve, figured specimen, USNM 173798. 

27. Left valve, figured specimen, USNM 173797. 

28. Eukloedenella soloensis n. sp. (p. 29). 

Right valve, holotype, GSC 29442, from the Prongs Creek Formation, Ludvigsen collection V-3. 
PROFESSIONAL PAPER 825 PLATE II 

BAIRD/A, BAIRDIOLITES?, BEECHERELLA?, ACANTHOSCAPHA, RECTOBAJR'DIA, 

SHIDELERITES, EUKLOEDENELLA, AND POLONIELLA (FRAMELLA) 
FIGURES 

PLATE 12 

[All figures X 30] 

1-3. "Tricornina" caurina n. sp. (p. 33). 

Lateral, posterior, and dorsal views of right valve, holotype, GSC 29448, from the Prongs Creek Formation, Ludvigsen collection V -3. 

4. Tric.ornina sp. (p. 34). 

Broken left valve, figured specimen, GSC 29510, from the Michelle Formation, Ludvigsen collection 1-3. 

5-7. Bicornina sp. (p. 34). 

5, 7. Left-lateral and dorsal views, figured specimen, USNM 173810, from the McCann Hill Chert, 

USGS collection 7037-SD. 

6. Left-lateral view of carapace, figured specimen, USNM 173809, from the McCann Hill Chert, 

USGS collection 6492-SD. 

8, 9. Berounella sp. aff. B. minuta Blumenstengel, 1970 (p. 34). 

Right-lateral and dorsal views, figured specimen, USNM 173811, from the McCann Hill Chert, USGS 

collection 7037-SD. 

10, 11. Bairdiocypris? sp. cf. B.? cordiformis Rozhdestvenskaya, 1959 (p. 35). 

10. Right-lateral view of carapace, figured specimen, GSC 29450, from the Prongs Creek Formation, 

Ludvigsen collection V-3. 

11. Right-lateral view of small carapace, figured specimen, USNM 173840, from the McCann Hill 

Chert, USGS collection 7037-SD. 

12. Bairdiocypris sp. (p. 35). 

Right-lateral view of carapace, figured specimen, GSC 29476, from the Prongs Creek Formation, Ludvigsen collection V -3. 

13-25. K uresaaria blackstonensis n. sp. ( p. 35). 

13. Right-lateral view of small carapace, paratype, USNM 173818, from the McCann Hill Chert, 

USGS collection 6492-SD. 

14. Interior of left valv:e, paratype, USNM 173816, from the McCann Hill Chert, USGS collection 

7037-SD. 

15. Dorsal view of carapace, paratype, USNM 173817, from the McCann Hill Chert, USGS collection 7032-SD. 

16. Interior of left valve, paratype, GSC 29490, from the Michelle Formation, Ludvigsen collection II-13, showing hinge. 

17. Interior of right valve, paratype, GSC 29492, from the Michelle Formation, Ludvigsen collection II-13, showing hinge and muscle scar. 

18. Right view of carapace, holotype, GSC 29487, from the Prongs Creek Formation, Ludvigsen 

collection V -3. 

19. Right valve, paratype, GSC 29491, from the Michelle Formation, Ludvigsen collection II-13. 

20. Left valve, paratype, GSC 29488, from the Michelle Formation, Ludvigsen collection 11-13. 

21. Broken specimen, paratype, GSC 29493, from the Michelle Formation, Ludvigsen collection 11-

13, showing thickness of shell. 

22. Interior of left valve, paratype, GSC 29489, from the Michelle Formation, Ludvigsen collection 11-13, showing muscle scar and ventral stop ridges. 

23. Right view of corroded carapace, paratype, USNM 173815, from the McCann Hill Chert, USGS 

collection 6492-SD, showing possible mural pores replaced by silica. 

24, 25. Right-lateral and left-lateral views of large carapace, paratype, USNM 170343, from the McCann Hill Chert, USGS collection 6492-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 12 

"TRICORNINA;' BICORNINA, BEROUNELLA, BAIRDIOCYPRIS?, BAIRDIOCYPRIS, AND KURESAARIA 
PLATE 13 

[All figures X SO] 

FIGURES 1-4. Camdenidea sp., from the McCann Hill Chert, USGS collection 7047-SD (p. 33) . 

1. Right valve, figured specimen, USNM 173813. 

2, 3. Left-lateral and interior views, figured specimen, USNM 173814. 

4. Left-lateral view of carapace, figured specimen, USNM 173812. 

5-7. Praepilatina sp. aff. P. praepilata sibirica Polenova, 1970, from the McCann Hill Chert, USGS collection 

7437-SD (p. 36). 

5. Small right valve, figured specimen, USNM 173825. 

6. Interior of small right valve, figured specimen, USNM 173826. 

7. Large left valve, figured specimen, USNM 173827. 

8-11. Bairdiohealdites? scapulatus n. sp., from the McCann Hill Chert (p. 36). 

8, 9. Right-lateral and dorsal views of carapace, holotype, USNM 173819, USGS collection 7033-

SD. 

10. Interior of left valve, paratype, USNM 173824, USGS collection 7037-SD, showing muscle 

scar. 

11. Interior of left valve, paratype, USNM 173820, USGS collection 6492-SD, showing character of dorsal margin. 

12-17. Voronina sp. cf. V. inventa Rozhdestvenskaya, 1962, from the McCann Hill Chert (p. 37). 

12-14. Left-lateral right-lateral, and dorsal views of carapace, figured specimen, USNM 173828, 

USGS collection 7032-SD. 

15, 16. Right-lateral and interior views, figured specimen, USNM 173829, USGS collection 6492- SD. 

17. Left-lateral view of large carapace, figured specimen, USNM 173830, USGS collection 7032-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 13 

CAMDENIDEA, PRAEPILATINA, BAIRDIOHEALDITES?, AND VORONINA 
FIGURES 

PLATE 14 

[All figures X 30 1 

1,2. Eriella? sp. (p. 39). 

1. Right valve, figured specimen, USNM 173834, from the McCann Hill Chert, USGS collection 

7037-SD. 

2. Right valve, figured specimen, GSC 29452, from the Michelle Formation, Ludvigsen collection 

I-3. 

3, 4. Microcheilinella? sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p. 39). 

3. Right-lateral view of carapace, figured specimen, GSC 29515. 

4. Dorsal view of carapace, figured specimen, GSC 29514. 

5-11. Neocraterellina? crescentifera n. sp., from the McCann Hill Chert, USGS collection 6492-SD (p. 39). 

5, 6. Right-lateral and ventral views of carapace, paratype, USNM 173836. 

7. Left valve, paratype, USNM 170336. 

8, 9. Right-lateral and dorsal views of carapace, holotype, USNM 173835. 

10. Interior of left valve, paratype, USNM 173837. 

11. Interior of left valve, para type, U SNM 173838. 

12-14. Cavellina (lnvisibila)? sp., from the McCann Hill Chert, USGS collection 7037-SD (p. 37). 

12, 13. Right-lateral and left-lateral views of carapace, figured specimen, USNM 173848. 

14. Interior of right valve, figured specimen, USNM 173849. 

15, 16. Ostracode indet. 3 (p. 40). 

15. Right-lateral view of carapace, figured specimen, GSC 29517, from the Prongs Creek Formation, Ludvigsen collection V-3. 

16. Dorsal view of carapace, figured specimen, GSC 29516, from the Prongs Creek Formation, 

Ludvigsen collection V -3. 

17, 18. Newsomites? sp. (p. 31). 

Right-lateral and dorsal views of carapace, figured specimen, USNM 173847, from the McCann Hill 

Chert, USGS collection 7037-SD. 

19. Barychilina? sp. (p. 36). 

Right valve, figured specimen, GSC 29451, from the Michelle Formation, Ludvigsen collection I-3. 

20. Ostracode indet. 1 (p. 40). 

Broken right valve, figured specimen, GSC 29511, from the Michelle Formation, Ludvigsen collection 

1-3. 

21. Trypetera? sp. (p. 37). 

Broken right valve, figured specimen, GSC 29447, from the Michelle Formation, Ludvigsen collection 

11-13. 

22. Ostracode indet. 2 (p. 40). 

Left valve, figured specimen, USNM 173839, from the McCann Hill Chert, USGS collection 6492-SD. 

23. Pachydomellid indet. 2 ( p. 38). 

Left valve, figured specimen, USNM 173846, from the McCann Hill Chert, USGS collection 7037-SD. 

24-26. Pachydomellid indet. 1 (p. 38). 

24. Left valve, figured specimen, USNM 173832, from the McCann Hill Chert, USGS collection 

7037-SD. 

25, 26. Right-lateral and dorsal views of carapace, figured specimen, USNM 173833, from the McCann 

Hill Chert, USGS collection 7032-SD. 

27-29. Tubulibairdia sp. (p. 38). 

27, 28. Right-lateral and dorsal views of broken carapace, figured specimen, USNM 173831, from the 

McCann Hill Chert, USGS collection 7032-SD. 

29. Right-lateral view of carapace, figured specimen, GSC 29475, from the Prongs Creek Formation, Ludvigsen collection V -3. 

« U. S. GOVERNMENT PRINTING OFFICE : 1973 0 - 509-058 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 14 

ERIELLA?, MICROCHEILINELLA?, NEOCRATERELLINA?, CA VELLINA (INVISIBILA)?, NEWSOMITES?, 

BAR YCHILINA?, TR YPETERA?, TUBULIBAIRDIA, AND OSTRACODES INDET