Late Paleozoic 

Gastropoda from 

Northern Alaska

By ELLIS L. YOCHELSON and J. THOMAS DUTRO, JR.

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

GEOLOGICAL SURVEY PROFESSIONAL PAPER 334-D

Descriptions and illustrations of 34. species and I 

new genus, with brief discussion of their stratigraphic significance

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1960
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

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

Washington 25, D.C. - Price 50 cents (paper cover)
CONTENTS

Page

Abstract-._ _-______---_-_-_________________-___-___ 111

Introduction-_------------_-________________.___.__ Ill

Stratigraphic distribution of the gastropods.___________ 113

Rock units-_______-__________________________-_ 113

Faunal zones_-------_---_--___-_______________- 115

Stratigraphic distribution___-__-_______-___._____ 115

Lower Mississippian undifferentiated. 

Upper Mississippian._______________

Permian,_________________________

Ecological and paleogeographical data_ _ ______

General considerations._____________________

Register of localities-_______________________

115

118

118

119

121

122

Page

Systematic paleontology----------------------------- 131

Superfamily Bellerophontacea____________________ 13]

Superfamily Euomphalacea_ _____________________ 133

Superf amily Pleurotomariacea_ ___________________ 135

Superfamily Platyceratacea______________________ 140

Superfamily Microdomatacea_____---__----_-_--__ 141

Superfamily Anomphalacea.______________________ 142

Superfamily Neritacea-_____-_-------------__--_- 142

Superfamily Murchisoniacea______________________ 144

Superfamily Loxonematacea._____--_------------- 144

Superfamily Subulitacea.________________________ 144

Class Scaphopoda_______________________________ 144

References cited____-___________-__-_____-_-----____ 145

Index-____________________________________________ 147

ILLUSTRATIONS

[Plates follow p. 148]

PLATES 12, 13, and 14. Late Paleozoic Gastropoda. pa&e 

FIGURE 23. Index map of northern Alaska._____-______________________________________--_____--__-_-_------_-_-__ 112

24. Mississippian Stratigraphic nomenclature and faunal zones.____________________--_--_----__----------_--_ 114

25. Ranges of gastropod species._________________________________________________________________________ 120

26. Schematic representation of terms for direction of growth lines____________________________ _______________ 121

27. Fossil-collecting localities in parts of the Misheguk Mountain quadrangle (^4), the Noatak quadrangle (B), the

Point Hope quadrangle (C), and the Howard Pass and Misheguk Mountain quadrangles (D), Alaska________ 123

28. Fossil-collecting localities in parts of the Killik River and Chandler Lake quadrangles (A), and the Chandler

Lake and Philip Smith Mountains quadrangles (B), Alaska.___________________________________________ 124

29. Fossil-collecting localities in parts of the Demarcation Point and Table Mountain quadrangles, Alaska and adjacent parts of Canada (A), and the Sagavanirktok and Mount Michelson quadrangles, Alaska (B)_________ 125

TABLE

TABLE 1. Distribution and number of Late Paleozoic gastropods in northern Alaska______________________________---_- 116

SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA

by ELLIS L. YOCHELSON and J. THOMAS DUTRO, Jr.

ABSTRACT

Late Paleozoic gastropods from northern Alaska occur in 

rocks of both Mississippian and Permian age; most of the 

fossils studied came from the Mississippian. Although the 

gastropods are of use for dating the rocks only in the broadest 

terms, locally they are useful in establishing informal faunal 

zonation. On the basis of predominant occurrence of certain 

gastropods, it is possible to distinguish rocks of Early Mississippian, Late Mississippian, and Permian age. Two divisions, based on the distribution of gastropods, are distinguished 

in the Upper Mississippian. One collection, consisting entirely 

of specimens of Glabrocingidum and Trepospira, may indicate 

the presence of rocks of Pennsylvanian age. Occurrence and 

distribution data are summarized in tabular form.

The gastropod faunule is composed primarily of euomphalaceans, platycerataceans, pleurotomariaceans, neritaceans, and 

bellerophontaceans, in that order of abimdance. There is no 

indication that a distinct boreal fauna is represented. Many 

of the specimens are poorly preserved, though some well-preserved shells occur, particularly among the pleurotomariaceans.

Thirty-four species are recognized in the systematic treatment ; nine of these are formally named as new species and 

one is referred to a previously described species. One new 

pleurotoniariacean genus, Nodospira, is described. At least 

two other new genera may occur in the faunule but specimens 

are too incomplete for adequate taxonomic description. The 

occurrence of two scaphopod specimens is reported.

Most of the fossils were collected from the Brooks Range 

during field work in connection with geologic investigations of 

Naval Petroleum Reserve No. 4 and adjacent areas. Some 

earlier collections from northern Alaska were restudied.

INTRODUCTION

This study deals primarily with specimens collected 

from 1944 to 1953 during the geologic exploration of 

Naval Petroleum Reserve No. 4. This is one of a 

series of papers by members of the U.S. Geological 

Survey planned to describe the various groups of Paleozoic fossils collected in northern Alaska. Mackenzie 

Gordon, Jr. (1957) has completed a study of the Mississippian cephalopods. Work on certain other fossil groups is in progress.

The philosophy that has guided this work was expressed by J. Brookes Knight (1953, p. 84) who, in

describing a poorly preserved Permian gastropod 

fauna from Mexico, remarked: "* * * a collection of 

fossils from beds in a region previously unstudied may 

tell us much, even though the specimens themselves 

are too poorly preserved to warrant detailed descriptions or naming of species/' Most of the fossil gastropods from northern Alaska are poorly preserved; 

nevertheless, their study contributes to our understanding of the classification and geographic distribution of Paleozoic gastropods. In addition, it presents detailed information useful in regional stratigraphic studies.

Mississippian gastropods were first collected from 

the Brooks Range by Philip S. Smith in 1911 (Smith, 

1913). George H. Girty listed gastropods from northern Alaska in several U.S. Geological Survey Bulletins, but did not describe any of the species. Most 

of his identifications are summarized in a single chart 

(Smith and Mertie, 1930, facing p. 182). Specimens 

identified by Girty were reexamined during the present investigation. A few dozen specimens were collected by A. G. Maddren, J. M. Jessup, and G. L. 

Harrington during the geologic reconnaissance of the 

Alaska-Canada boundary (Maddren, 1912, p. 297- 

314). Finally, several gastropods were obtained by 

E. de K. Leffingwell (1919) from the Canning Fiver 

district.

The paleontologic literature of Alaska is well indexed. Dutro (1956) compiled an annotated bibliography of Alaskan Paleozoic paleontology; in addition, 

Alaska is included in the excellent "Arctic Bibliography11 (U.S. Department of Defense, 1953-57). 

Neither of these sources records late Paleozoic gastropods from Alaska. About half a dozen papers illustrate a few specimens from other parts of the Arctic, 

but all figures examined are small-size reproductions 

of poorly preserved specimens. These few specimens 

are either unnamed or are compared with species described from western Europe.

Ill
to

168

140°

164 160° 156 152° 148° 144°

Outcrop of Mississippian rocks Approximate limit of outcrop of 

Siksikpuk formation

Approximate limit of outcrop of Approximate limit of outcrop of 

unnamed Permian formation Sadlerochit formation

O

FIGURE 23. Index map of northern Alaska showing quadrangles referred to In text, locations of figures 27, 28, and 29, generalized outcrop belt of Misslssippian rocks, and approximate

distribution of Permian rn<>k units.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 113

C. C. Branson's bibliographic index of Permian fossils described through 194:1 (Branson, 194:8) aids a 

search of the literature for previously named species. 

Mississippian fossils, on the other hand, have not been 

systematically indexed for many years. To the best 

of the writers' knowledge, the last major papers dealing with gastropods of Mississippian age or early 

Carboniferous, are those of Koninck (1881, 1883). 

Literature describing American Mississippian gastropods is scant.

The Brooks Eange physiographic province includes 

several distinct groups of mountains extending from 

near the 165th meridian eastward to the Canadian 

boundary. For most of its length the range lies essentially along the 68th parallel, forming the backbone of Alaska and constituting the divide for drainage to the Pacific and Arctic Oceans. Eastward from 

the 150th meridian the range makes a crescentic bend 

northeastward until the mountain front is only about 

25 miles south of the Arctic coast. The regional setting and topography were described in detail by 

Smith and Mertie (1930) and summarized by Payne 

and others (1951). The index map (fig. 23) shows 

the quadrangles from which gastropod specimens were 

collected.

The topography of the Brooks Range has been extensively modified by glacial action. Glaciers are not 

now common, but the climate remains severe. The 

isolated position of the region has complicated and 

handicapped fossil collecting. Many collections were 

backpacked by geologists from the collecting localities and cached in places accessible by airplane. This 

necessarily limited the number and size of the fossil 

collections. A few of the localities were visited more 

than once; most have been only casually sampled.

More than customary acknowledgment is due the 

fieldmeii because fielclwork in northern Alaska is rigorous and requires physical effort not normally associated with fossil collecting. Members, or former 

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

fossil material on which this paper is based are: A. L. 

Bowsher, W. P. Brosge, R. M. Chapman, R. L. Detterman, J. T. Dutro, Jr., Alien Feeler, W. A. Fischer, 

George Gryc, C. J. Gudim, A. S. Keller, B. H. Kent, 

C. E. Kirschner, A. H. Lachenbruch, M. D. Mangus, 

R. H. Morris, W. W. Patton, Jr., H. N. Reiser, E. G. 

Sable, I. L. Tailleur, and R. F. Thurrell, Jr.

Dr. J. Brookes Knight, Smithsonian Institution, retired, examined some of the specimens and made pertinent taxonomic suggestions. Photographs were 

taken by Nelson W. Shupe, U.S. Geological Survey.

STRATIGRAPHIC DISTRIBUTION OF THE GASTROPODS

The assemblage of gastropod genera dates the rocks 

as late Paleozoic, but the gastropods themselves are 

of little value in correlating individual stratigraphic 

units with rock sequences in regions outside Alaska. 

With the exception of PortlocMetta sp., Rkineoderma'l sp., and Twho-nellinal lata, n. sp., no g?,nera 

or species thought to be limited to rocks of Mississippian age are known. No species or genera diagnostic 

of Permian age were identified.

On the other hand, fieldwork has demonstrated that 

some of the gastropods are useful, locally, in providing supplementary evidence that helps determine the 

position of certain rock units. Units currently recognized in northern Alaska are discussed below on 

the basis of distribution of the gastropods.

ROCK UNITS

Rocks of late Paleozoic age in northern Alaska can 

be assigned to at least six formations. The Mississippian system, represented largely by a complex array of carbonate facies, is divided into two major 

parts. The nomenclature of Mississippian rock units 

in the central Brooks Range (fig. 24:) has been revised by Bowsher and Dutro (1957, p. 3-7). The 

lower part, essentially a black shale with a sandstone 

member at the base and argillaceous limestone beds 

near the top, is designated as the Kayak shale. The 

upper part, the Lisburne group, consists of the Wachsmuth limestone below and the Alapah limestone above. 

Elsewhere in northern Alaska, the Lisburne group has 

been subdivided into several formations, not as yet 

formally published. The approximate limits of the 

Mississippian outcrop belt are shown in figure 23.

No rocks of undoubted Pennsylvania!! age are known 

from northern Alaska. A carbonate rock sequence in 

the eastern Brooks Range, lying above the Alapah 

limestone, may represent some part of the Pennsylvania!! system. Fossils are rare in these rocks and no 

gastropods have been collected from them.

The Permian is represented by three quite different 

formations, each of which represents a predominantly 

clastic facies. The approximate limits of outcrop of 

these units are shown in figure 23. The Sadlerochit 

formation of Permian and Early Triassic age in the 

eastern Brooks Range was first defined as the Sadlerochit sandstone by Leffingwell (1919, p. 103). Its 

fauna was studied by Girty and, although the fc^mation was originally called Pennsylvania!!, it was Girty 

who recognized affinities with faunas now considered 

to be of Permian age (Smith, 1939, p. 32). The Siksikpuk formation of Permian(?) age in the central 

Brooks Range was described recently by W. W. Pat-
114 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

FORMATION FAUNAL ZONE

Alapah limestone

Wachsmuth limestone

Upper limestone

Fine-grained limestone

Gigantoproductus striato-sutmtus (Schwetzoff)

Light-gray limestone Lithostmtiontlla* sp.

Chert-shale

Cmiatitft crtnistna Philhl

Sciophyltum lambarti 

Marker and MacLaren

Platy limeston Eunietria ivstata (Hall)

Dark limestone Lithostrotwn aff. L. asiatieum 

(Yabe and Hayasaka)*

Shaly limestone tf tNaheopstsl suturimmpta Yochelson and Dutro*

Banded chert-limeston

Bmrhythyris suborheu/aris (Hall)*

Spirifer tenuteostatus (Hall)

Crinoidal limestone "Zaphrentis" komntki s. 1. 

Milne Edwards and Haime*

Red limestone 

Upper black shale

CryptMastus aff C. pis«n 

(Meek and Worthen)

Leptatna analiign (Phillips)

* Gastropod bearing.

FIGURE 24. Mississippian stratigraphic nomenclature and faunal zones in the Shainin Lake area, 

central Brooks Range (modified from Bowsher and Dutro, 1957).
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 115

ton, Jr. (1957, p. 41-43). It is essentially a finegrained clastic facies of the Sadlerochit formation. 

In some areas a minor amount of silicification is recorded. The third formation of Permian age, as yet 

unnamed, is a thick sequence of sandstone, quartzose 

limestone, shale, chert, and conglomerate that crops 

out extensively in the western part of the Brooks 

Range. This unit has produced the greatest variety 

of Permian fossils in northern Alaska and is correlative, in part, with the Sadlerochit and Siksikpuk 

formations.

FAUNAL ZONES

Mississippian collections yielding gastropods are 

listed in table 1 according to the faunal zones from 

which they were collected. These faunal zones were 

established by Bowsher and Dutro (1957, p. 5 and 6). 

Gastropods were collected from zones characterized 

by Scalaritu'ba sp., Leptaena analoga (Phillips), 

"Za-phrentis"1 konincki Milne Edwards and Haime 

(sensu lato), Brachythyris sul>orl>icularis (Hall), N. 

(Nnticopsis} suhmcompta Yochelson and Dutro, 

Lithostrotion cf. L. axiaticum (Yabe and Hayasaka), 

and Go-niatites crenistria Phillips (fig. 24 and table 1).

Gastropods were the basis for the erection of one of 

the faunal zones of Bowsher and Dutro. The fauna 

of the iVaticopsts houn Dawson zone (Bowsher and 

Dutro, 1957, p. 6) is essentially limited to gastropods. 

The species referred to as N. howi by Bowsher and 

Dutro is described in this paper as Naticopsis (Naticopsis] suturicompta, n. sp., and the name of the zoneis changed accordingly.

By an analysis of the cephalopoda of the Gomatites 

crenistria zone, these beds have been correlated with 

the latest Middle Visean and early Upper Visean by 

Gordon (1957, p. 15 and table 2). Regarding the 

cephalopod faunule, Gordon states (1957, p. 15) :

In the British section, forms identical with and closely related to the Alaskan species of the black chert and shale member are distributed through stratigraphic thicknesses of 150 

to nearly 400 feet. In the northern Alaska section, the fossils 

are limited to the lower 60 feet of the black chert and shale 

member. Goniatites suggesting three different subzones (B2, 

Pla and Pic) have been found at roughly the same stratigraphic level but each in a different river valley. Whether 

this means that the ranges of certain goniatite genera are 

somewhat telescoped in the Alaskan section, or whether the 

black chert and shale member transgresses the section rather 

irregularly, is not determinable on the basis of present evidence.

No faunal zones have been set up, as yet, for the 

Permian system in Alaska. The gastropod Straparolhis (Euomphalus} alaxkensis, n. sp. is commonly found 

in the lower part of the Siksikpuk formation, but has 

also been found in the other two Permian formations.

Several informal faunal zones have been distinguished 

in Dutro's research on the younger Permian, par^icularly in the unnamed rocks of the western Brooks 

Range. The only zone pertinent to this gastropod 

study is one characterized by Licharewia, a spiriferoid 

brachiopod that is of widespread occurrence in the 

upper Permian of Russia and parts of Europe and 

Asia. The gastropod Mo-urlmiml reloba, n. sp. occurs in this zone in northern Alaska.

Stratigraphic position was assigned to the individual collections either by the collector or by D itro. 

Dutro based certain of the assignments on observations made during fieldwork, knowledge of the lithology and regional stratigraphy, study of the general 

aspect of the fauna, and position of the collection 

within measured sections. These assignments are used 

in placing collections in the faunal or rock units listed 

in table 1. Within each unit, collections are listed in 

numerical order.

Principal causes of uncertainty as to stratigraphic 

placement of collections are increasing stratigraphic 

refinement as the fieldwork progressed, incomplete 

stratigraphic sequences, and poor preservation of fossils. Collections from measured type sections, or from 

closely associated sections on which considerable reliance as to correct stratigraphic assignment can be 

placed, are indicated by reference to footnote 1 preceding the locality number.

STRATIGBAPHIC DISTBIBUTION 

LOWER MISSISSIPPIAN TTNDIFFEKENTIATED

The Lower Mississippian rocks of northern Alaska 

include the Kayak shale and the Wachsmuth limestone, 

each of which contains three faunal zones (fig. 24). 

The few snails collected from these zones provide, in 

themselves, 110 basis for distinguishing any one zone 

from another. Accordingly, most collections fron localities other than type sections are treated as Lower 

Mississippian imdifferentiated.

The most important difference between the Lower 

and Upper Mississippian gastropod faunules is the 

apparent abundance of platycerataceans in the earlier 

beds compared with a virtual absence in the later 

beds. This may be simply a matter of facies, Platyceras apparently being able to live only on pelmatozoan echinoderms (Bowsher, 1955). Suitable habitats for crinoids apparently were few in Late Mississippian seas of northern Alaska. Most platyceratid specimens occur in dark bioclastic limestone containing much crinoidal debris. Platyceratids do cccur 

in Permian rocks and, rarely, in the Upper Mississippian of this region. Their presence is not, in itself, 

an index of an Early Mississippian age.
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Trepospira (Trepospira) sp .... (Angyomphalus'!) Trepospira 

si>. ......................... Mourlonia minuta, n. sp___ ._

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Spiroscala cf. Ssp-__ 

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f'n»vtltltmn'> or.

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Phymatopleura sp-____-__ New genus? A .. 

New genus? B . 

Indet pi eurotomariacean. . 

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Indet. neritacean. .

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Indet. inurchisoniacean 

Loxonematacea: Loionema sp 

Indet. loxonematacean __.

Subulitacea: 

lanthinopsis"! sp.. 

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Genus indet

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lred i2TnSve /(ien tYP6 SeCtl dely 1nassoclated section whch considerable °n rreliance beplaced on to correct stratigraphic assignments. can as tifiration
118 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Turbonellina'l lata n. sp. is found only in rocks of 

Early Mississippiaii age. Several other species are 

known from single specimens and little reliance can 

be placed on them for stratigraphic determinations. 

Ammatina rocky montanum (Shinier) is more common in the Lower Mississippiaii than in the Upper 

Mississippiaii. Euomphalaceans, mostly indeterminate 

as to genus and species, are more common in the Lower 

Mississippiaii; bellerophontaceans, also mostly indeterminate as to species, are less abundant. Pleurotomareans are less common and individual specimens 

are smaller in the Lower Mississippiaii than in the 

Upper Mississippian. Finally, iieritaceans are much 

rarer in the Lower Mississippiaii than in later beds.

UPPEK MISSISSIPPIAN

Naticopsis and Lithostrotion zones. Collections 

from the Naticopsis zone of the Upper Mississippian 

Alapah limestone, constitute a gastropod faunule 

composed primarily of large neritaceans and large 

bellerophontaceans. Most specimens are steinkerns in 

a blocky black limestone matrix. One specimen of 

Anenmtina and an indeterminate euomphalacean were 

also collected from rocks of this zone.

The Lithostrotion- zone yields a more diversified 

gastropod faunule. Nearly half the specimens are 

euomphalaceans, a considerable number of which cannot be assigned to genus with any degree of confidence. Several specimens are identified as Straparollus (Euomphalus} brooksenxis, n. sp. Other gastropods from this zone are single specimens of Porflock- 

?WZa? sp., Rhineoderm-a-1. sp., AnomphaJus sp., an indeterminate niiirchisoniaceaii, and an indeterminate 

neritaceaii. Two specimens each of Anematina and 

an indeterminate species of pleurotomariacean complete the faunule.

Neither zone can be distinguished solely on the 

basis of gastropod species present, although colleclections from the Lithostrotion zone show more taxonomic variety than those from the Naticopsis zone. 

In addition, many of the species and genera found in 

these two zones also occur in rocks of Early Mississippiaii age. Among these are Betterophon sp., Anematina rockymontanum- (Shimer), fttraparottus (Euomphahts} brooksensis, 11. sp., and, tentatively, 

Naticopsis (Naticopsis} sutiiricompta, n. sp. Nevertheless, fieldwork has demonstrated that the dark 

matrix and large size of the specimens from the 

Naticopsis zone are distinctive.

Certain collections from among those listed in table 

1 as '''Naticopsis or Lithostrotion- zones' 1 seem more 

likely to represent the Naticopsis zone. In this category are USGS (U.S. Geological Survey) localities

11799 and 13287. On much less certain grounds, collections from USGS localities 976 and 5430 may also 

represent the Naticopsis zone. Other collections cannot be assigned to either zone with any degree of 

confidence.

Goniatites zone and probable Goniatites zone. This 

assemblage, dominated by the large pleurotomariaceans Benibexial inunibilicata^ 11. sp. and Nodospira 

ornata^ 11. gen., n. sp., is the most distinctive of the 

gastropod faimules studied. With the exception of 

Euphemites and Loxonema, of which one and two 

specimens, respectively, occur in the Lower Mississippian, all specifically identifiable gastropods from rocks 

assigned to this zone are limited to it. Within this 

zone, cephalopods and gastropods occur together at 

USGS localities 11828, 11865, and 1208-t.

These gastropod studies suggest strongly that the 

collections listed as "probable Goniatites zone" in table 

1 should be referred to that zone without question. 

Nettsonial sp. and Euphemites sp. occur in both sets 

of collections, along with Nodospira orrmta, n. sp. and 

Bembexial iniimbilicata, 11. sp. In addition, Mourlonia mimita, n. sp. is present in collections questionably referred to the Goniatites zone and may be represented by a steinkern in a collection definitely from 

the Goniatites zone.

Upper Mississippian, undi-fferentiated. All specimens referred to this listing are exceedingly poorly 

preserved. No significant stratigraphic statement can 

be made on the basis of the available material.

PERMIAN

Euomphalaceans constitute nearly two-thirds of the 

Permian gastropod assemblage. Pleurotomariaceans, 

most of which are indeterminate as to genus and species, comprise much of the remainder but they are 

widely distributed and occur in nearly as many collections as the euomphalaceans. Several indeterminate bellerophontaceans and Platyceras complete the 

assemblage. The presence of Platyceris in beds of 

Permian age indicates that, in Alaska, the genus cannot be used as a guide to the Mississippian.

The euomphalacean species appear tc be relatively 

reliable guide fossils to the Permian rocks. Two of 

these species, StraparoUus (Euomphah'-s) alaskensis, 

11. sp. and Am.phiscapha (Cylicioscapha) grada, n. sp. 

are described. Among the pleurotomariaceans, Mourlonial reloba, 11. sp. is the most common species. 

Many kinds of pleurotoniariaceans seem to be represented in the poorly preserved material from the Permian of northern Alaska.

The gastropods suggest faunal relationships among 

the Siksikpuk, Sadlerochit, and unnamed Permian
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 119

formations. StraparoUus (EuompJialus} alaskensis, 

n. sp. occurs in all three formations, and Amphiscapha 

(C ylicioscapha] grada, n. sp. is present in the latter 

two. Finally, Mourfonia'l reloba, n. sp. occurs in the 

unnamed formation, is tentatively identified in collections from the Siksikpuk formation, and may be present in the Sadierochit formation.

USGS locality 14174, assigned to the Siksikpuk 

formation on the basis of rock type, is atypical. The 

collection consists of two specimens of Glabrocingulum 

(Glabrocingulum) sp. and one specimen of Trepospira 

(Trepospira) sp. Except for one questionable occurrence, Trepospira is unknown in Permian faunas elsewhere in the world. Furthermore, the specimens of 

Glabrocijiguhim differ from Permian species known 

from the southwestern United States and other wellknown areas of Permian exposures. It may be that 

this collection is actually of Pennsylvaniaii age. More 

fieldwork in northern Alaska and additional collections are needed to confirm the presence of Pennsylvanian rocks.

Known ranges of the more significant species are 

shown in figure 25.

ECOLOGICAL AND PALEOGEOGRAPHICAL DATA

Representatives of five superfamilies euomphalaceaiis, platycerataceans, pleurotomariaceans, neritaceans, and bellerophontaceans, in that order of abundance comprise virtually all the gastropods studied. 

The groups are represented by nearly equal numbers 

of specimens, with the euomphalaceans being perhaps 

half again as abundant as the bellerophontaceans. 

Although many of the pleurotomariaceans are poorly 

preserved, this group has considerably more generic 

diversity than the others.

Individual collections show little taxonomic variety. 

Less than 10 percent of the collections contain more 

than three taxa. This lack of diversification may reflect the small amount of collecting or it may, in part, 

reflect a time of unfavorable or relatively uniform environment. For example, fossils of Lower Mississippian strata of the western United States have been 

collected for nearly 100 years, but relatively few gastropods are known. It could be more than coincidence 

that both regions were the sites of predominantly clastic limestone deposition during the late Paleozoic.

Ecologic and paleogeographic inferences drawn 

from this study are listed below. Further work is 

needed before the generalizations can be applied to 

upper Paleozoic gastropods from other regions. These 

inferences involve examination of other fossil groups 

in the late Paleozoic faunas of the region. Documentation of some of the statements must necessarily

await the publication of research by other specialists.

1. Platyceras commonly occurs here in crinoidal limestone. This partially supports the hypothesis concerning life relationships of platyceratids on pelmatozoan calyxes (Bowsher, 1955).

2. In the Lower Mississippian where Platycerc# is 

common, the associated gastropods show less ^ariety than in the Upper Mississippian. This suggests that areas of limestone deposition favorable 

for crinoids were unfavorable for most benthonic 

gastropods.

3. StraparoUus occurs in limestone, sandstone, siltstone, and shale. This suggests that species of this 

genus had considerable ecologic tolerance.

4. Although large gastropods (an inch or mor?, in 

height) are not confined to the coarse clastic facies, 

they are the only snails that have been collected 

from rocks of this facies. These large gastropods 

apparently lived in a zone of heavy surf, the probable sedimentary depositional environment of the 

coarse clastic material. Some of the large shells 

occur in a siliceous conglomeratic matrix containing pebbles half an inch in diameter.

5. Cephalopods are rarely associated with the gastropods; the 2 groups occur together at only 6 lo~alities. Corals and gastropods also appear to be nearly 

mutually exclusive, although details of coral distribution have not been published as yet. On the 

other hand, except in the Naticopsis sutnricampta 

zone, gastropods are commonly associated with numerous taxonomically diversified brachiopods. Apparently environments favorable for diversified 

brachiopod faunas afforded optimum conditions for 

abundant gastropods. Conversely, it seems that only 

certain kinds of gastropods were able to live in environments well suited for corals and cephalop ods.

6. In the Naticopsis suturicompta zone, except for one 

collection, fossil assemblages consist entirely of gastropods. There is no obvious explanation for this 

apparent exclusion of other fossil invertebrates', 

Mississippian collections include genera known to 

be common in the lower Carboniferous elsewhere in 

the world. Heretofore they have not been reported 

from the American Arctic, and knowledge of their 

stratigraphic occurrence and geographic distribution 

fills an important gap in our information on paleogeographic distribution. There is no evidence at the 

family level, and most probably none at the gereric 

level, that any of the groups is conspicuously present 

or absent because of cold-water conditions. So far as 

can be interpreted from this study, a boreal marine 

invertebrate fauna did not exist in Mississippian time. 

The snail faunule is not particularly different, in gen507218
to

o

"~~~~~- - ^____SiYSTEM

TAXON~~~~^--^^__^^

Belleroptwn sp.

Straparollus (Euompkalus) brooksensis 

Yochelson and Dutro, n. sp.

Straparollus (Euomphalns) alaskensis 

Yochelson and Dutro, n. sp.

Amphiscapka (Cylicwscapka) grada 

Yochelson and Dutro, n. sp.

Trepospira (Trepospira) sp.

Mourlonia minuta 

Yochelson and Dutro, n. sp.

Mourtonia1! reloba 

Yochelson and Dutro, n. sp.

Nodospira ornata 

Yochelson and Dutro, n. sp.

Bembexial inumbilicata 

Yochelson and Dutro, n. sp.

Glabrocingulum (Glabrocingulum) sp. 

Neilsonial sp 

Platyceras (Platyceras) sp. 

Platyceras (Orthonychia) sp.

Anematina rockymantanum 

(Shimer)

Naticopsis (Natieopsis) suturicompta 

Yochelson and Dutro, n. sp.

CARBONIFEROUS

MISSISSIPPIAN

Kayak shale

?-H 

Lisburne group

Wachsmuth limestone

1 1 

1 

| | 

1 1 1 1 

1 

Alapah limestone

 H 1

 M

7 7 j ?

1 ? 

1 H

1 ?

?

?

 1 

-H «

-HI 1

PENNSYLVANIA!!!?*

? 1 ? 

? 1 ?

PERMIAN

Lower

H 1

7 

j 

| 

Upper

T

 i_?

T

 i

 i

tdd

H i i 

O

* 

00

400

I_

400 800

I

1200 Feet

FIGURE 25. Known ranges of the more significant late Paleozoic gastropod spectes in northern Alaska. Thickness of Mississippian rocks plotted to scale of type sections; Pennsylvania^?) and Permian thicknesses diagrammatic. Known occurrences indicated by vertical lines; question marks indicate doubt as to precise position with respect to type sections. 

Stratigraphic range, controlled by two or more occurrences, shown by horizontal bar; dashed bar indicates questionable range.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 121

eral aspect, from faunules found in Mississippian 

limestones of the western United States.

The abundance of many kinds of rugose corals, including both solitary and colonial forms, is contributing evidence to the consideration of the Mississippian 

in northern Alaska as a time of relatively warm shallow seas.

Permian collections are, unfortunately, too small 

and too scattered geographically to give any indication about climatic zonation. Stehli (1957) suggests 

that tropical and temperate zones occupied wider belts 

of latitude in Permian time than at the present.

GENERAL CONSIDERATIONS

A new classification of Paleozoic gastropods was 

completed recently by Knight, Batten, and Yochelson (in press). That classification is employed 

in this paper, except that Amphiscapha Knight is 

treated as a distinct genus rather than as a subgenus 

of Straparollus Montfort. Systematic descriptions are 

arranged in biologic order rather than in stratigraphic 

order.

Morphologic terminology employed is that of 

Knight (1941, p. 23-28) *and Cox (1955). Three 

terms not in common usage, referring to the course 

of growth lines over the shell, are "opisthocline," a 

course forward and downward; "orthocline," essentially straight downward; and "prosocline," backward 

and downward with reference to the aperture of the 

shell and the axis of coiling. These are shown diFICURE 26. Schematic representation of terms for 

direction of growth lines.

agrammatically in figure 26. Linear measurements in 

millimeters are given for the types of new species. 

Angular measurements were made with the axis of 

coiling vertical. They represent approximate rather 

than precise slope angles. Most ornament can be 

classed as either "colabraV parallel to the outer lip 

and growth lines, or "spiral,11 revolving around the 

whorls and parallel to the suture.

Because most of the collections contain few individuals, it is difficult to determine the variation within 

what might be considered a single population. More 

than one-third of the collections include only 011°, gastropod specimen, and about three-fourths of th°. collections have less than five gastropod specimens. The 

number of specimens identified in each taxon is listed 

on table 1.

The collection from USNM (U.S. National Museum) locality 3089 differs from the others in that it 

consists of silicified shells recovered by dissolving 

limestone blocks in hydrochloric acid. Commonly, 

more and better preserved specimens can be obtained 

by this method than can be collected by mechanical 

preparation from limestone. Further collecting in the 

region should be directed particularly toward a search 

for silicified fossils.

Most of the specimens are not well preserved; the 

illustrated specimens constitute a significant percentage of the better specimens. Taxonomic and stratigraphic conclusions based on poorly preserved material are necessarily less satisfactory than those based 

on better material.

Preservation seems to be related directly tc two 

factors. First, most of the collections are from relatively compact limestone. Because of the structure 

of the molluscan shell, exfoliated specimens are commonly produced when material is broken from a dense 

carbonate matrix. By way of contrast, identifiable 

brachiopods, and other types of fossils, commonly may 

be broken from a limestone matrix. Second, the severe climate of the high latitudes apparently permits 

little chemical weathering of shales and shaly limestones. In addition, an insignificant amount of disintegration appears related to frost action. In other 

regions, limy shales often produce the most abundant and best preserved molluscan shells. The small 

amount of weathering also seems to limit the actual 

number of specimens available at any one outcrop.

Because few specimens are available for study, an 

open system of nomenclature has been adopted, and 

formal names have been applied only to well-preserved 

material. Specific names are applied to 10 of tH 34 

forms recognized. In addition, because this is the
122 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

first study of gastropods from northern Alaska, the 

authors have proposed new names in every case but 

one, rather than use the terms "cf." or "aft1 ." to compare these specimens with species described from clisstant localities. Future studies based on new collections may place some of these names in synonymy 

with species described from regions far removed from 

northern Alaska. As a general principle, however, it 

seems wiser to erect new species. Indiscriminate identification of material with previously named species 

can imply unwarranted correlations.

This study suggests that several new generic categories are needed for Mississippian gastropods. With 

one exception the number of specimens available is too 

small or the specimens themselves are too poorly preserved to serve as a suitable basis for establishing new 

genera. Revision of the Mississippian gastropods, 

particularly the pleurotomariaceans, is needed to make 

them more useful for stratigraphic and biologic 

studies.

One unorthodox treatment is incorporated in this 

taxonomic study. Following each superfamily a brief 

section is devoted to material which would normally 

be considered as indeterminate. The possible systematic placement of some of the specimens is discussed 

briefly. It is recognized that these suggested identifications are not well founded, and, accordingly, they 

are clearly separated from the rest of the systematic 

study. These should be considered only as first approximations. Because of the considerable effort and 

relatively great expense involved in collecting the material from nothern Alaska, we feel that this attempt 

to obtain the maximum amount of stratigraphic information is justified. These scraps of additional information, together with suggestions of age significance based on studies of other elements of the total 

fauna, may eventually lead to the solution of some of 

the local stratigraphic problems. All specimens briefly 

mentioned are listed as indeterminate on table 1.

REGISTER OF LOCALITIES

Locality Nos. 3087 through 3279 refer to collections 

in the possession of the U.S. National Museum. Following them, localities of the U.S. Geological Survey 

are listed. Except for types and figured specimens 

transferred to the National Museum, tlnse collections 

are in the possession of the Geological Survey. Locality 7118b is a "green1" number in an old general 

register of Paleozoic localities. All ether numbers 

refer to the "blue" register of localities currently being maintained by the Upper Paleozoic Unit, Paleontology and Stratigraphy Branch. Collections 406 

through 1015 were made by members of earlier surveys. Collections from localities 9184 through 15829 

were made by members of the Navy Oil Unit, Alaskan Geology Branch.

Latitude and longitude given for the localities are 

based on the best data available to the collectors at 

the time this register was compiled (January 1957). 

Many geographic positions were plotted on the 

1:250,000-scale quadrangle map series published by 

the Geological Survey. Other positions were taken 

from the 1:48,000-scale preliminary mr p series compiled for the Geological Survey program of geologic 

mapping in Navy Petroleum Reserve No. 4 and adjacent areas.

Index maps (figs. 27, 28, and 29) showing the approximate positions of the localities are based on the 

World Aeronautical Chart series (maps 62-64, and 

76) published by the U.S. Coast and Geodetic Survey, 

(scale 1:1,000,000).
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 123

161' 160° 162°30'

68° 30' -

11865 X (H861 

U1867 

11890

68°45'-

B

166 C

159" 158' 157 C

*<K *

N| 14169^<

^oc,^*14947

68*30'

D

FIGDRE 27. Fossil-collecting localities in parts of the Misheguk Mountain quadrangle (A), the Noatak quadrangle (B), 

the Point Hope quadrangle (C), and the Howard Pass and Misheguk Mountain quadrangles (D), Alaska.
124 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

154 C 153' 152'

68° 30

151" 150° 149° 148°

68°30'

A? Nanushuk

, Lake ^3107

3087

3087a

3091 /x 13170

3113 3088

3115 3167

3186 3182

3188

14954

Itkillik

Laker, X^3172 

3089X 3173 

X 13272 

3100

CHANDLER LAKE PHILIP SMITH MOUNTAINS

FIGURE 28. Fossil-collecting localities in parts of the Killik River and Chandler Lake quadrangles (A) and the 

Chandler Lake and Philip Smith Mountains quadrangles (B), Alaska.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA

142° 141°

125

147° 146° 145°

69° 30' -~

FIGURE 29. Fossil-collecting localities in parts of the Demarcation Point and Table Mountain quadrangles, Alaska, and adjacent parts of Canada (A) and the Sagavanirktok and Monnt Michelson 

quadrangles, Alaska (B).
126 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

Register of localities

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic posi'fon and age

USNM 3087

3087a

3088

3089

3091

3095

3098

3100

3107

3110

3113

3115

3164

3167

3169

3170

F 7 of 11 June. 

F 1 of 13 June 

F 3 of 16 June

F 1 of 16 June.

F 5 of 24 July.

F 2 of 27 August.___

F 1 of 3 June.

F 3 of 22 June.

F 1 of 22 June.

F 2 of 20 August..--

F 2 of 21 July_-.___ 

F 6 of 23 July ____ 

F 3 of 3 August.---- 

F 1 of 12 July 

F 2 of 24 July ____

F 6 of 24 July.

F 1 of 28 August..__

F 1 of 23 Julv.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Shainin Lake area, 

southwest corner of ridge, top of Sugarloaf Hill; lat 

68°19'20" N., long 150°55'30" W.; measured section J, 84.5-93.3 ft above base of Alapha limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

same locality as 3087; 49 ft above base of Alapah 

limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

along west side of main ridge southeast of lake; lat 

68°22'20" N., long 150°29'34" W., 80 ft above base 

of Alapah limestone.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Philip Smith 

Mountains quadrangle; Itkillik Lake area, north 

slope of hill about 11,100 ft S. 85° E. of Itkillik Lake 

camp; lat 68°24'15" N., long 149°43'20" W.; 139- 

145 ft above base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Chandler Lake 

quadrangle; Shainin Lake area, top of lower massive 

cliff, southwest slope of Mount Wachsmuth; lat 

68° 18'50" N., long 150°55'25" W.; measured section 

I, 141.6-148 ft above base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T.. Jr.; 1949; Chandler Lake 

quadrangle; Shainin Lake area, head of small creek 

about 14,700 ft. S. 8° E. of Shainin Lake camp; lat 

68°16'25" N. long 150°57'25"W.; 720-777 ft above 

base of Kayak shale.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J., Feder, 

A.; 1949; Chandler Lake quadrangle; Shainin Lake 

area, north side of first valley south of Pinnacles; lat 

68° 17' N., long 150°55'15" W., 187-198 ft above 

base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T. Jr.; 1949; Philip Smith 

Mountains quadrangle; Itkillik Lake area, 8,500 ft 

S. 40° E. of Itkillik Lake camp; lat 68°23'15" N., 

long 149°45'50" W.; 73-75 ft above base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

south side of ridge, 10,000 ft N. 12° W. of Nanushuk 

Lake camp; lat 68°25'10" N., long 150°30'15" W.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

6,800 ft east of Nanushuk Lake camp; lat 68°23'30" 

N., long 150°26'20" W.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Chandler Lake 

quadrangle; Shainin Lake area, south face of Sugarloaf 

Hill; lat 68°18'50" N., long 150°55'35" W.; 957 ft 

above base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; same locality as 

3113; 845-849 ft above base of Wachsmuth limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

about 1,800 ft S. 34°E. of Nanushuk Lake camp; lat 

68°23'10" N., long 150°28'45" W.; lower 30 ft of 

Alapah limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

about 6,900 ft S. 6° W. of Nanushuk Lake camp; lat 

68°22'15" N., long 150°29'35" W.; 97-113 ft above 

base of Alapah limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Philip Smith Mountains quadrangle; Itkillik Lake 

area, about 13,900 ft N.60° E. of Itkillik Lake camp; 

lat 68°25'25" N., long 149°43'40" W.; 86.3 ft above 

base of Alapah limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Chandler Lake quadrangle; Nanushuk Lake area, 

about 2,500 ft N. 65° E. of Nanushuk Lake camp; lat 

68°23'40" N., long 150°28' W.; about 60 ft above 

base of Alapah limestone.

Dark limestone member, Alapah 

limestone Lithostrotion aff. L. 

asiaticum zone; Upper Mississippian.

Shaly limestone member, Alapah limestone; Naticopsis suturicompta zone; Upper Missississippian.

Shaly limestone member, Alapah 

limestone; Naticopsis suturicornpta zone; Upper Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; " Zaphrentis" konincH zone; Lower 

Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; "Zaphrentis" konind'i zone; Lower 

Mississippian.

Argillaceous limestone member, 

Kayak shale; Leptaena analoga 

zone; Lower Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; " Zaphrentis" konind'i zone; Lower 

Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone "Zaphrentis" konincH zone; Lower 

Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; " Zaphrentis" konincH zone; Lower 

Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; "Zaphrentis" konincki zone; Lower 

Mississippian.

Banded limestone n ember, Wachsmuth limestone; Brachythyris 

suborbicularis zone; Lower Mississippian.

Banded limestone member, Wachsmuth limestone; Brachythyris 

suborbicularis zone; Lower Mississippian.

Shaly limestone member, Alapah 

limestone; Naticopsis suturicompta zone; Upper Mississippian.

Dark limestone member, Alapah 

limestone; Litho->trotion aff. L. 

asiaticum zone; Upper Mississippian.

Dark limestone member, Alapah 

limestone; Lithostrotion aff. L. 

asiaticum zone; Upper Mississippian.

Shaly limestone member, Alapah 

limestone; Naticopsis suturicompta zone; Upper Mississippian.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 

Register of localities Continued

127

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic position and a^e

USNM 3171

3172

3173

3182

3186

3188

3247

3272

3279

USGS 7118b 

(Green)

USGS 406

408a

960

971

972

975

976

979

982

987

989a

F 4 of 11 August____

F 3 of 23 August..__

F 2 of 25 August....

F 1 of 26 July.

F 4 of 7 August. 

F 5 of 7 August. 

F 6 of 6 July _.

F 3 of 24 August-...

F 1 of 20 June.

19 D-__-_- 

11 Md 26._

11 Md 28a.

12 Md31._ 

12 Md 40.. 

12 Md 41__ 

12 Md 44_. 

12 Md 46__

12 Md 49. 

12 Md 53- 

12 Md 59- 

12 Md 61-

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Philip Smith 

Mountains quadrangle; Itkillik Lake area, about 

13,600 ft N. 60° E. of Itkillik Lake camp; lat 68°20'25' 

N., long 149° 43'05" W.; 63 ft above base of Alapah 

limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

same locality as 3171; about 140 ft above base of 

Alapah limestone.

Bowsher, A. L., Dutro, J. T., Jr., Gudim, C. J.; 1949; 

Philip Smith Mountains quadrangle; Itkillik Lake 

area, about 12,200 ft N. 65° E. of Itkillik Lake 

camp; lat 68°25'12" N., long 149°43'10" W.; float at 

b&SG of SGction

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Chandler Lake 

quadrangle; Nanushuk Lake area, about, 6,900 ft S. 

6° W. of Nanushuk Lake camp; lat. 68°22'25" N., 

long 149°43'40" W.; 80 ft above base of Alapah limestone.

Bowsher, A. L., Gryc, G., Fischer, W.; 1949; Chandler 

Lake quadrangle; Shainin Lake area, near south end 

of Sugarloaf Hill; lat 68°19'25" N., long 150°55'30" 

W.; 172 ft above base of Alapah limestone.

Bowsher, A. L., Gryc, G., Fischer, W.; 1949; same 

locality as 3186; 0.3 ft above locality 3186.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Chandler Lake 

quadrangle; Shainin Lake area, about 8,000 ft S. 32° 

W. of Shainin Lake camp; lat 68°17'45" N., long 

150°56'30" W.; 795.3-798 ft above base of Kayak 

shale.

Bowsher, A. L., Dutro, J. T., Jr.; 1949; Philip Smith 

Mountains quadrangle; Itkillik Lake area; lat 

68°25'30" N., long 149°42'40" W.; 91 ft above base 

of Alapah limestone.

Bowsher, A. L.; 1950; Chandler Lake quadrangle; upper 

Alapah Creek, about 600 ft S. 80° E. of Alapah 

Creek camp; lat 68°10'18" N., long 150°46'20" W.; 

lower 44 ft of Wachsniuth limestone.-

Leffingwell, E. de K.; 1908; Mount Michelson quadrangle, Ikiakpaurak vallev; approximate lat 69°28' 

N., long 145°50' W.

Maddren, A. G.; 1911; International Boundary Survey; 

about 4 mi south of east camp on Joe Creek of Firth 

River; lat 68°53'40" N., long 140°57'30" W.

Maddren, A. G.; 1911; International Boundary Survey; 

about 2 mi west of west camp on Joe Creek; lat 

68°57' N., long 141°22'30" W.

Jessup, J. M.; 1912: International Boundary Survey; 

west side of You Creek, north end of ridge; lat 68°44' 

N., long 141°04'25" W.

Jessup, J. M.; 1912; International Boundary Survey; 

northeast slope of main fork of Incog Creek; lat 

68°46'30" N., long 140°56" W.

Jessup, J. M.; 1912; International Boundary Survey; 

northeast slope of main fork of Incog Creek, near 

head of creek; lat 68°47'10" N., long 140°57'55" W.

Jessup, J. M.; 1912; International Boundarv Survey; 

southwest slope of Turner Mountain; lat 68°48'50" 

N., long 140°56'W.

Maddren, A. G.; 1912; International Boundary Survey; 

west end of Turner Mountain, on east slope of upper 

Boulevard Creek; lat 68°49'50" N., long 140°58'35" 

W.

Harrington, G. L.; 1912; International Boundary Survey; mountain spur 2}£ mi southeast of Joe Creek 

camp; lat 68°53'40" N., long 140°56' W.

Jessup, J. M.; 1912; International Boundary Survey; 

1 mi south of Joe Creek and % mi east of 141st 

meridian; lat 68°54'30" N., long 140°59'30" W.

Maddren, A. G.; 1912; International Boundary 

Survey; I}i0 mi west of 141st meridian, south of Joe 

Creek*; lat 68°55' N., long 141°03' W.

Maddren, A. G.; 1912; International Boundary 

Survey; north bank of Joe Creek, % mi west of 141st 

meridian; lat 68°55'30" N., long 141°02' W.

Shaly limestone member, Alapah 

limestone; Naticopsis suturicompta zone; Upper Mississippian.

Dark limestone member, Alapah 

limestone; Lithostrotion aff. L. 

asiaticum zone; Upper Mississippian.

Crinoidal limestone member, 

Wachsniuth limestone; "Zaphrentis" konincki zone; Lower 

Mississippian.

Shaly limestone member, Alapah 

limestone; Naticopsis suturicompta zone; Upper Mississippian.

Dark limestone member, Alapah 

limestone; Lithostrotion aff. L. 

asiaticum zone; Upper Mississippian.

Dark limestone member, Alapah 

limestone; Lithostrotion aff. L. 

asiaticum zone; Upper Mississippian.

Argillaceous limestone member 

Kayak shale; Leptaena analoga 

zone; Lower Mississippian.

Dark limestone member, Alapah 

limestone; Lithostrotion aff. L, 

asiaticum zone; Upper Missippian.

Shaly limestone member (?), 

Wachsniuth limestone; "Zaphrentis" konincki zone; Lower 

Mississippian.

Sadlerochit formation; Permian.

Alapah limestone (?), Lisburne 

group; Upper Mississippian(?).

Permian (?).

Permian (?).

Lisburne group; Upper Mississippian.

Alapah limestone, Lisburne 

group; Upper Mississippian.

Alapah limestone, Lisburne 

group; Upper Mississippian.

Alapah limestone, Lisburne 

group; Upper Mississippian.

Permian (?).

"Pennsylvanian shales" (of Maddren)"; Permian (?).

"Pennsylvanian shales" (of Maddren); Permian (?).

"Pennsylvanian shales" (of Maddren); Permian (?)
128 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Register of localities Continued

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic position and age

USGS 994

996

997

1004

1008

1009

1010

1014

1015

9184

9186

9187

10862

10868

10870

11785

11786

11799

11807

11808

11814

11815

11816

11823

12 Md 66. 

12 Md 68-

12 Md 69- 

12 Md 76-

12 Md 79-.

12 Md 80__ 

12 Md 81_.

12 Md 85-

12 Md 85a_ 

45 AKr 58-

45 AGr !___ 

45 AGr 2__. 

49 APa 384.

49 ATr 399-

48 ASa 47 _-

50 ABe 201.

50 ABe 200. 

50 ARr 49_.

50 ABe 115_

50 ABe 44_- 

50 AKe 238-

50 AKe 240- 

50 AKe 242_ 

50 AKt 329_

Harrington, G. L.; 1912; International Boundary 

Survey; ridge north of Joe Creek, from bed above 

reddish-weathering slaty limestone; lat 68°56'10" N., 

long 140°57'15" W.

Jessup, J. M.; 1912; International Boundary Survey; 

east slope of gulch north of Joe Creek, about % mi 

east of 141st meridian; lat 68°56'10" N., long 140°58' 

W.

Jessup, J. M.; 1912; same locality as 996; about 250 ft 

north of 996, along strike.

Maddren, A. G.; 1912; International Boundary 

Survey; northwest corner of limestone outcrop west 

of Tub Mountain; lat 68°58'50" N., long 141°06'35" 

W.

Harrington, G. L.; 1912; International Boundary 

Survev; south side Joe Creek, about 6^2 nil west of 

141st'meridian; lat 69°56'30" N., long 141°18' W.

Harrington, G. L.; 1912; same locality as 1008; about 

Ko mi west.

Jessup, J. M.; 1912; International Boundary Survey; 

north side Joe Creek valley about 1M mi west of 

141st meridian; lat 68°56' N., long 141°21' W.

Jessup, J. M.; 1912; Internitional Boundary Survey; 

north slope of gulch on vrest side Clarence River, 

about 1% mi west of 141so meridian; lat 69°25' N., 

long 141 °04' W.

Harrington, G. L.; 1912; same locality as 1014, from 

talus below outcrop.

Kirschner, C. E.; 1945; Killik River quadrangle; east 

bank of Okpikruak River, 16% mi S. 4° W. from 

forks of Killik River; lat 68°34'30" N., long. 

153°31' W.

Gryc, G.; 1945; Chandler Lake quadrangle; bluffs 

west of northernmost tip of Chandler Lake; lat 

68°17'30" N., long 152°36' W.

Gryc, G.; 1945; Chandler Lake quadrangle; bluffs 

west of northernmost tip of Chandler Lake; lat 

68° 17' N., long 152°36' W.

Patton, W. W., Jr.; 1949; Chandler Lake quadrangle; 

cutbank on north side of Monotls Creek; lat 68°22'- 

35" N., long 152°54' W.; from limestone bed overlying chert-shale member of Alapah limestone.

Tailleur, I. L.; 1949; Killik River quadrangle; cutbank 

on east side of Middle Fork of Okpikruak River; lat 

68°33' N., long 153°31' W.; near top of Alapah limestone.

Sable, E. G., Lachenbruch, A. H.; 1948; Mount Michelson quadrangle; north slope of Kikittut Mountain 

about 1 mi west of Hulahula River; lat 69°28' N., 

long 144°25' W.

Brosge, W. P.; 1950; Philip Smith Mountains quadrangle; Galbraith Lake area; approximate lat 68°29' 

N., long 149°13' W.; about 560 ft above base of 

Siksikpuk formation.

Brosge', W. P.; 1950; same locality and level as 11785__

Reiser, H. N.; 1950; Chandler Lake quadrangle; Siksikpuk River area; approximate lat 68°20' N., long 

151°50' W.; about 800 ft above base of Alapah limestone.

Reiser, H. N.; 1950; Chandler Lake quadrangle; Chandler Lake area, about 10,000 ft S. 85° E. of astronomical point on Little Chandler Lake; lat 68° 16'40" N., 

long 152°36'50" W.; 280 ft above base of Wachsinuth 

limestone.

Brosge, W. P.; 1950; same locality as 15408; 575 ft 

above base of Wachsmuth limestone.

Keller, A. S.; 1950; Chandler Lake quadrangle; cutbank 

on east side of Skimo Creek, a tributary of Tiglukpuk 

Creek; lat 68°17' N., long 151°53' W.; basal 60 ft of 

Siksikpuk formation.

Keller, A. S.; 1950; same locality as 11814; possibly 

slightly different Stratigraphic level.

Keller, A. S.; 1950; same locality as 11814; possibly 

slightly different Stratigraphic level.

Kent, B. H.; 1950; Howard Pass quadrangle; station K 

280; lat 68°36' N., long. 158°22' W.; in structurally 

complex area, Stratigraphic position unknown.

Alapah limestone, Lisburne group; 

Upper Mississippian.

Alapah limestone, Lisburne group; 

Upper Mississippian.

Alapah limestone, Lisburne group;

Upper Mississippian. 

Alapah limestone, Lisburne group ;

Upper Mississippian.

"Artinskian limestone" (of Maddren) ; Permian.

"Artinskian limestone" (of Maddren) ; Permian.

"Artinskian limestone" (of Maddren) , Permian.

Alapah limestone(?), Lisburne 

group; Upper Mississippian.

Alapah limestone. (?), Lisburne 

group; Upper Mississippian.

Alapah limestone, Lisburne group; 

Upper Mississipnian.

Lisburne group; Lower Mississippian (?).

Alapah limestone (?), Lisburne 

group; Upper Mississippian.

Alapah limestone; Goniatites crenistria zone; Upper Mississippian.

Alapah limestone Goniatites crenistria zone; Upper Mississippian.

Lisburne group; Upper Mississippian.

Siksikpuk formation; Permian(?).

Siksikpuk formation; Permian(?). 

Alapah limestone (middle part); 

Upper Mississipiian.

Wachsmuth limestone; Lower 

Mississippian.

Wachsmuth limestone; Lower

Mississippian. 

Siksikpuk formation; Permian(?).

Siksikpuk formation; Permian (?). 

Siksikpuk formation; Permian (?).

Unnamed Permiar formation (?); 

Permian (?).
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 

Register of localities Continued

129

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic position and age

USGS 11828

11843

11858

11861

11865

11867

11890

12084

12340

12342

12348

12355

12700

12701

12709

12773

12779

12785

12788

12798

13215

13216

13219

13222

13225

13228

13231

50 ATr 45-

50 ATr 189_

50 ASa 227 _

50 ASa 235. 

50 ASa 150. 

50 ASa 236 _

50 AMg 149__ 

F3 of 12 June.

50 ACh 41___. 

50 AKe 226_ _.

46 ATh 8... 

50 ABe 112.

11 AS 46__. 

11 AS 51-_-

50 ADu 16_

51 ATr 14_. 

51 ABe 5-_. 

11 AS77__. 

50 ADu 77 _

50 ADu 44.

51 ARr 100-

51 ARr 101- 

51 ARr 84- 

51 ARr 107- 

51 ATr 1__- 

51 ATr 10-- 

51 ATr 346-

Tailleur, I. L.; 1950; Howard Pass quadrangle; Etivluk 

River valley; lat 68°35' N., long 156°38' W.

Tailleur, I. L.; 1950; Howard Pass quadrangle; Ipnavik

River valley; lat 68°35' N., long 157°29' W. 

Sable, E. G.; 1950; Misheguk Mountain quadrangle; 

station Sa 350, Utukok River valley; 2 mi north of 

west fork of Utukok River; lat 68°34'40" N., long 

161°10'30" W.

Sable, E. G.; 1950; Misheguk Mountain quadrangle; 

2,800 ft southeast of locality 11858; lat 68°34'20" N., 

long 161°10' W.

Sable, E. G.; 1950; Misheguk Mountain quadrangle; 

station Sa 249, head of west fork of Utukok River; 

lat 68°34'40" N., long 161°16'50" W.

Sable, E. G.; 1950; Misheguk Mountain quadrangle; 

station Sa 350(15), north side of Kogruk Mountain, 

Utukok River valley; about 400 ft south of locality 

11861; lat 68°34'20" N., long 161° 10' W.

Mangus, M. D.; 1950; Misheguk Mountain quadrangle; 

divide between Iligluruk Creek and Kugururok 

River; lat 68°34' N., long 161°20'30" W.

Bowsher, A. L., Gryc, G.; 1950; Chandler Lake quadrangle; Anaktuvuk River valley; 1,500 ft east of 

Kanakutk Lake; lat 68°18' N., long 151°21' W.

Chapman, R.; 1950; Killik River quadrangle; Colamnagavik River valley; lat 68°35' N., long 154°32' W.

Keller, A. S.; 1950; Chandler Lake quadrangle; 100 ft 

south of locality 11814; lat 68°17' N., long 151°53' 

W.; upper 75 ft of Alapah limestone.

Thurrell, R.; 1946; Killik River quadrangle; upper 

Oolamnagavik River valley; lat 68°35' N., long 

154°32' W.

Gudim, C. J; 1950; Philip Smith Mountains quadrangle; 

Galbraith Lake area; approximate lat 68°28'30" N., 

long 149°21' W.; about 60 ft above base of Alapah 

limestone.

Smith, P. S.; 1911; Misheguk Mountain quadrangle; 

central Noatak River vallev; cutbank on south side 

of river; approximate lat 68°01' N., long 159°02' W.

Smith, P. S.; 1911; Misheguk Mountain quadrangle; 

central Noatak River valley, cutbank on north side 

of river; approximate lat 68°07'48" N., long 

159°53' W.

Dutro, J. T., Jr.; 1950; Misheguk Mountain quadrangle; Nimiuktuk River valley; lat 68°22'18" N., 

long 159°53'45" W.

Tailleur, I. L.; 1951; Howard Pass quadrangle; Ipnavik 

River valley; approximate lat 68°22' N.. long 157°28' W. *

Brosge, W. P.; 1951; Chandler Lake quadrangle; 

Monotis Creek section; lat 68°20' N., long 152°50'15" 

W. upper 100 ft of Alapah limestone.

Smith, P. S.; 1911; Noatak quadrangle; lower Noatak 

River valley; approximate lat 67°14'30" N., long 162°30' W."

Dutro, J. T., Jr.; 1950; Misheguk Mountain quadrangle; Nimiuktuk River valley; lat 68° 16'23" N., 

long 159°57'36" W.

Dutro, J. T., Jr.; 1950; Misheguk Mountain quadrangle; Nimiuktuk River valley; lat 68°24' N., long 

159°53' W.

Reiser, H. N.; 1951; Howard Pass quadrangle; station 

79d, Kiligwa River valley; lat 68°39' N., long 

158°38' W.

Reiser, H. N.; 1951; same locality as 13215; station 

79e.

Reiser, H. N.; 1951; Howard Pass quadrangle, Kiligwa 

River valley; lat 68°35' N., long 158°20' W.

Reiser, H. N.; 1951; Howard Pass quadrangle; same 

locality as 13219.

Tailleur, I. L.; 1951; Howard Pass quadrangle; Ipnavik 

River valley, lat 68°21' N., long 157°18' W.

Tailleur, I. L.; 1951; Howard Pass quadrangle; Ipnavik 

River valley; lat 68°22'30" N., long 157°15' W.

Tailleur, I. L.; 1951; Howard Pass quadrangle; Kuna 

River valley; lat. 68°22' N., long 157°42' W.

Lisburne group; Goniatites crenistria zone; Upper Mississippian.

Lisburne group(?); Lower Mississippian.

Lisburne group (lower formation) ; Lower Mississippfan.

Lisburne group (lower formation) ; Lower Mississippian.

Lisburne group (upper formation); Upper Mississippian.

Lisburne group (lower formation; Lower Mississippian.

Lisburne group (lower formation) ; Lower Mississippian.

Chert-shale member, Alapah limestone; Goniatites crenistria 

zone Upper Mississippian.

Alapah limestone (?); Upper Mississippian (?).

Alapah limestone; Upper Mississippian.

Alapah limestone (?); Upper Mississippian (?).

Shaly limestone member, Alapah 

limestone; Naticopsis suturicompta zone; Upper Mississippian.

Lisburne group (lower formation?); Lower Mississipnian.

Lisburne group; Lower Mississippian.

Lisburne group (lower formation); Lower Mississippfan.

Lisburne group; Lower Mississippian.

Chert-shale member, Alapah limestone; Goniatites crenistria 

zone; Upper Mississipp; an.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Unnamed. Permian formation; 

Permian.

Unnamed. Permian formation; 

Permian.

Kayak shale(?); Leptaena analoga 

zone(?); Lower Mississiopian.

Kayak shale(?); Scalarituba 

zone(?); Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Kayak shale; Leptaena analoga 

zone; Lower Mississippfan.
130 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 

Register of localities Continued

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic posit'on and age

USGS 13232

13234

13235

13236

13237

13238

13240

13241

13242

13245

13246

13247

13252

13254

13255

13258

13278

13286

13287

13288

13292

14035

14074

14097

14099

14150

14151

14152

14169

51 ATr 347_ 

51 ATr 350_ 

51 ATr 351_ 

51 ATr 352_ 

51 ATr 353- 

51 ATr 354- 

51 ATr 392_ 

51 ATr 393_ 

51 ATr 394- 

51 ATr 406. 

51 ATr 412. 

51 ATr 162- 

51 ATr 323-

51 ATr 328-

51 ATr 329 _ 

51 AKi 124. 

50 ABe 31.-

50 ABe 43.

50 ABe 45__ 

50 ABe 46_ _ 

50 ABe 117_

50 ARr 18-- 

49 AMg91_

49 ALa 5__-

50 ARr 23_ _ 

53 APa 105-

53 ABo.

Tailleur, I. L.; 1951; same locality as 13231.

Tailleur, I. L.; 1951; same locality as 13231... 

Tailleur, I. L.; 1951; same locality as 13231... 

Tailleur, I. L.; 1951; same locality as 13231..

Tailleur, I. L.; 1951; same locality as 13231.

Tailleur, I. L.; 1951; same locality as 13231...

Tailleur, I. L.; 1951; Howard Pass quadrangle; Kiligwa

River valley; lat 68°32' N., long 158°51' W. 

Tailleur, I. L.; 1951; same locality as 13240___-.-.--

Tailleur, I. L.; 1951; same locality as 13240 

Tailleur, I. L.; 1951; Howard Pass quadrangle; Kiligwa

River valley; lat 68°33' N., long 158°53' W. 

Tailleur, I. L.; 1951; Howard Pass quadrangle; Kiligwa

River valley; lat 68°30'30" N., long 158°48' W. 

Reiser, H. N.; 1951; Howard Pass quadrangle; Kiligwa

River valley; lat 68°33' N., long 158°54' W. 

Tailleur, I. L.; 1951; Howard Pass quadrangle; station

T-91, Kiligwa River valley; lat 68°25' N., long

158°26' W. 

Tailleur, I. L.; 1951; Howard Pass quadrangle; station

T-92, Kiligwa River valley; lat. 68°25' N., long

158C 27' W. 

Tailleur, I. L.; 1951; same locality as 13254__-._.-..

53 APa 122_ 

53 ASa 43--

Kent, B. H.; 1951; Howard Pass quadrangle; Kuna 

River valley; lat 68°22' N., long 157°42' W.

Brosge., W. P.; 1950; Chandler Lake quadrangle; 

Chandler Lake area; lat 68°18'30" N., long 

152°40'30" W.; section B-20, 40 ft above base of 

Wachsmuth limestone.

Brosge, W. P.; 1950; Chandler Lake quadrangle; 

11,000 ft N. 86° E. of astronomical point on Little 

Chandler Lake; lat 68° 17' N., long 152°36'30" W.; 

about 500-550 ft above base of Wachsmuth limestone.

Brosg4, W. P.; 1950; same locality as 13286; from float 

about 800 ft above base of Lisburne group (may be 

basal Alapah limestone).

Brosge, W. P.; 1950; same locality as 13286; from 

about 200 ft above base of Alapah limestone.

Gudim, C. J., Reiser, H. N.; 1950; Chandler Lake 

quadrangle; 5 mi west of Little Chandler Lake, from 

southern Lisburne klippe; lat 68° 18' N., long 152°45' 

W.; about 250 ft above base of Wachsmuth limestone.

Reiser, H. N.; 1950; Philip Smith Mountains quadrangle; Galbraith Lake area; lat 68°29' N., long 

149°13' W., possibly from upper part of formation.

Mangus, M. D.; 1949; Howard Pass quadrangle; 

about 5 mi east of Howard Pass Lake; lat 68° 12' N., 

long 156°38' W.

Lachenbruch, A. H.; 1949; Howard Pass quadrangle; 

Etivluk River valley, cutbank in Fay Creek, 5 mi 

west of Etivluk River; lat 68°20' N., long 156°53' W.

Reiser, H. N.; 1950; Philip Smith Mountains quadrangle; Galbraith Lake area; lat 68°29' N., long 

149° 13' W.; basal bed of Siksikpuk formation.

Patton, W. W., Jr., Bowsher, A. L., 1953; Chandler 

Lake quadrangle; cutbank near head of Kiruktagiak 

River; lat 68°20'30" N., long 152°54' W.; top of 

Alapah limestone.

Patton, W. W., Jr., Bowsher, A. L.; 1953; same locality 

as 14150.

Patton, W. W., Jr., 1953; same locality as 11814..._..

Sable, E. G.; 1953; Misheguk Mountain quadrangle; 

Nuka River valley; lat 68°39'30" N., long 159° 16' W.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Kayak shale(?); Leptaena analoga 

zone; Lower Miesissippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Kayak shale(?); Scalarituba 

zone(?); Lower Mississippian.

Lisburne group; Upper Mississippian (?).

Kayak shale(?); Leptaena analoga zone; Lower Mississippian.

Kayak shale (?); Leptaena analoga zone(?); Lower Mississippian.

Lisburne group; Lower Mississippian.

Lisburne group; Lower Mississippian.

Kayak shale; Leptaena analoga 

zone(?); Lower Mississippian.

Wachsmuth limestone; Brachythyris sub orbicular is zone; 

Lower Mississipnian.

Wachsmuth limestone; Brachythyris suborbicvlaris zone(?); 

Lower Mississipnian.

Alapah limestone (?); Naticopsis 

suturicompta zone or Lithostrotion zone; Upper Mississippian.

Alapah limestone; Lithostrotion 

aff. L. asiaticum zone; Upper 

Mississippian.

Wachsmuth limestone; Lower 

Mississippian.

Alapah limestone (upper part?); 

Upper Mississippian.

Wachsmuth limestone; "Zaphrentis" konincki zone(?); Lower 

Mississippian.

Wachsmuth limestone; Lower 

Mississippian.

Siksikpuk formation (basal part) ; 

Permian (?).

Chert-shale member(?); Alapah 

limestone; Goniatites crenistria 

zone; Upper Mi«sissippian.

Chert-shale (?) member; Alapah 

limestone; Goniatites crenistria 

zone; Upper Mississippian.

Siksikpuk formation (basal part); 

Permian(?).

Unnamed Permian formation; 

Permian.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA

Register of localities Continued

131

Locality No. Field No. Collector, year of collection, and description of locality Stratigraphic position and age

USGS 14174

14947

14954

14965

14984

14992

15408

15430

15453

15826

15829

49 ATr 449A.

53 ATr 79__- 

F4 of 2 June.

F3 of 10 June.

50 ABe 22.

50 ABe 3_- 

50 ABe 33.

47 AGr 182. 

53 ASa 247_

53 ABo 18__ 

51 ADt 147.

51 AKe 162.

52 AMo 5_- 

52 AMo 37 _

Tailleur, I. L.; 1949; Chandler Lake quadrangle; rubble

west of Kiruktagiak River; lat 68°23' N., long

152°54' W. 

Tailleur, I. L.; 1951; Misheguk Mountain quadrangle,

Nuka River valley; lat 68°36' N., long 159° 18' W. 

Bowsher, A. L.; 1950; Chandler Lake quadrangle;

Shainin Lake area; lat 68°19'21" N., long 150°55' W.

Bowsher, A. L.; 1950; Chandler Lake quadrangle; 

Shainin Lake area; lat 68°19'20" N., long 150°53'30" 

W.

Brosge', W. P.; 1950; Philip Smith Mountain quadrangle; Galbraith Lake area; lat 68°26' N., long 

149°22' W.

Brosge, W. P.; 1950; Chandler Lake quadrangle; Anaktuvuk River valley; lat 68°16'30" N., long 151°34' W.

Brosge', W. P.; 1950; Chandler Lake quadrangle; 

Chandler Lake area; lat 68° 17' N., long 152°36'30" 

W.; from section B-17.

Gryc, G.; 1947; Mt. Michelson quadrangle; Canning 

River area; lat 69° 17' N., long 145°59' W.

Sable, E. G.; 1953; Point Hope quadrangle; Cape 

Lisburne area, north side of Lisburne Hills; lat 

68°49' N., long 165°58' W.

Bowsher, A. L.; 1953; Point Hope quadrangle; Cape 

Lisburne area; approximate lat 68°52' N., long 

166°08' W.

Detterman, R. L.; 1951; Philip Smith Mountains 

quadrangle; Lupine River; lat 68°49' N., long 

148°22'30" W.

Keller, A. S.; 1951; Philip Smith Mountains quadrangle; Ribdon River, about 3 mi southwest of 

Elusive Lake; lat 68°40'10" N., long 148°27'45" W.; 

100 ft above base of Sadlerochit formation.

Morris, R. H.; 1952; Sagavanirktok quadrangle; 

Kemik Creek; lat 69°20'30" N., long 147°02' W.; 

10 ft above base of Sadlerochit formation.

Morris, R. H.; 1952; Mt. Michelson quadrangle; Cache 

Creek, Canning River; lat 69°28' N., long 145°49' W.

Siksikpuk(?) formation; Permian(?).

Lisburne group; Upper Mississippian (?).

Banded limestone member, 

Wachsmuth limestone; Brachythyris suborbicularis zone; 

Lower Mississippian.

Crinoidal limestone member, 

Wachsmuth limestone; "Zaphrentis" konincki zone; Lower 

Mississippian.

Alapah limestone (lower part) 

Upper Mississippian.

Alapah limestone (lower part); 

Upper Mississippian.

Alapah limestone; Naticopsis suturicompta zone; Uppe"1 Mississippian.

Alapah limestone; Upper Mississippian.

Siksikpuk formation; Permian(?).

Lisburne group; Upper Mississippian.

Sadlerochit formation 

part); Permian.

(basal 

Sadlerochit formation; Permian.

Sadlerochit formation; Permian.

Sadlerochit formation (basal 

part); Permian.

SYSTEMATIC PALEONTOLOGY

Class GASTROPODA

Superorder PROSOBRANCHIA

Order ARCHAEOGASTROPODA

Superfamily BELLEROPHONTACEA

Family SINTTITIDAE

Subfamily EUPHEMITINAE

Genus EUPHEMITES Warthin, 1930

Euphemites sp. 

Plate 12, figures 2-4

Discussion. Several specimens retain patches of 

shell showing the spiral lirae characteristic of the 

genus. One specimen has at least 18 lirae from one 

umbilicus to near the selenizone; all other specimens 

are less complete and lirae cannot be counted. The 

selenizone is relatively wide and slightly depressed. 

At least the first third of the body whorl is secondarily smoothed by a thin inductural layer or layers. Most specimens are of uniform size, about 12 mm 

across the axis of coiling. All are regularly and 

smoothly coiled.

Steinkerns, or internal fillings of the shells, have 

been referred to this species in one instance. These 

steinkerns are of the same general size and shape and 

occur in the same collection as identifiable specimens 

of Euphemites. To check this identification, an artificial steinkern was prepared by removing the shell from 

a specimen. This steinkern and the naturally occurring ones all show slightly wider umbilici with steeper 

walls than do steinkerns referred to Belterophcn.

Illustrated specimens. USNM 136507a, 136507b; USGS locality 12084.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 12340, two. Alapah limestone: USGS locality 12084, nine.

Family BELLEROPHONTIDAE

Subfamily BELLEROPHONTINAE

Genus BELLEROPHON Montfort, 1808

Bellerophon sp. 

Plate 12, figures 5-9

Discussion. Bellerophontacean steinkerns are common; three of these retain patches of shell showing

507218 O 6C
132 SHORTER CONTRIBUTIONS TO GENERAL! GEOLOGY

growth lines and a selenizone characteristic of Bellerophon. Other steinkerns were identified as Bellerophon by comparison with these three specimens. 

Most identifications of steinkerns as Bellerophon were 

based on the character of the umbilical openings. 

Among the Alaskan specimens at least, the umbilical 

openings are relatively narrower and have more arched 

walls and a slightly less abrupt juncture of side and 

umbilical opening than in umbilici in steinkerns referred to Euphemites. It is to be emphasized that 

these are not characters of the shell; there is suggestive evidence that the shell itself may have been 

anomphalous. Some of the steinkerns that exceed the 

size of the largest known specimens of Eupheinites 

are called Bellerophon sp. even though the umbilical 

characters of the steinkern are not certainly known.

Although some specimens are well rounded along 

the dorsum, having only a faint ridge at the position 

of the selenizone, others have flattened sides and a 

more prominent crestlike dorsum. In several, the dorsum is wide and depressed in the center. It is possible that these belle rophontaceans with flattened 

sides represent another taxon. Until better specimens 

are obtained so that this hypothesis can be tested, 

all the material is assigned to one species with some 

of the specimens presumed to have been compressed 

during deformation of the enclosing strata.

Several of the specimens are quite large for the 

genus; such an individual, measuring over 70 mm 

across the aperture, is shown on plate 12, figure 9. 

The only described American late Paleozoic species 

that approaches this size is the poorly known Bellerophon giganteu-s Worthen. Slightly larger specimens of Bellerophon have been illustrated by Koninck (1883) from the Carboniferous of Belgium.

In most cases steinkerns are of little use in paleontology and, indeed, specific identification of them can 

often do more harm than good. It may well be that 

several biologic species are included here under Belleropho>n sp. However, inasmuch as many of these 

specimens come from a single stratigraphic unit, it 

seems reasonable to conclude that these specimens belong to a single species. The occurrence of bellerophontacean steinkerns of this sort has been shown to 

be a good field guide to rocks of the lower part of the 

Alapah limestone and its equivalents. Because of the 

occurrence of similar steinkerns in both older and 

younger rocks in northern Alaska, caution is urged 

in their use for age determination. At best, these 

steinkerns should be used only to supplement more 

positive evidence of the age of a rock unit.

Illustrated specimens USNM 136508a, 1365(Fb, USNM locality 3088; USNM 136509, USGS locality 11799; USNM 

136510, USGS locality 15408.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 11807, one; 11808, one; 13234, one; 

13235, one. Alapah limestone: USGS locality 976, eight; 

13287, four; 15408, two; USNM locality 3088, nine; 3172, one. 

Upper Mississippian undifferentiated: USGS locality 11799, 

four.

Subfamily KNIGHTITINAE

Genus KNIGHTITES Moore, 1941

Submenus RETISPIRA Knight, 1945a

Knightites (Retispira?) sp. 

Plate 12, figure 1

Discussion. Identification is based on a single incomplete Mississippian specimen, showing spiral lirae 

and a raised selenizone. Uncertainty as to identification arises from two sources. First, the specimen is 

so incomplete that apertural characters, particularly 

the presence or absence of a ridge on the floor of the 

aperture, cannot be determined. Second, there is a 

slight chance that the specimen may be a pleurotomariacean, genus indeterminate, with the upper part 

of the shell destroyed. Orienting plate 12 with the 

left margin, downward shows the basis for this possible identification.

A second small poorly preserved specimen, of questionable Permian age, is more certainly referable to 

the subgenus. It cannot be determined if it is conspecific with the other specimen, and it is too poorly 

preserved to be illustrated or treated separately.

Illustrated specim en. USNM 136506, USGS locality 11843.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 11843, one. ?Permian: USGS 408a, 

one.

INDETERMINATE BELLEROPHONTAC! A.NS

Discussion. In addition to the material discussed 

above, other poorly preserved and indeterminate specimens may represent this superfamily. For a few of 

them, however, it is possible to assay a generic assignment. Collections not commented upon b?,low can be 

determined only to the superfamily level.

Occurrence and abundance. Kayak shale: USGS locality 

13245, may be Euphemites sp.; 13258, one, may be a Bellerophon, matrix differs from that yielding Bellerophon sp. Wachsmuth limestone: USNM locality 3115, one, may be a Bellerophon, matrix differs from that yielding Selleropt on sp. Lower 

Mississippian undifferentiated: USGS locality 11867, not a 

Bellerophon, in gross form this specimen reseirbles Sinuitina 

Knight, 1945a. Alapah limestone: USGS locality 406, one; 

1004, six; 14151, one; 14992, one. Upper Misstesippian undifferentiated: USGS locality 975, eight, slight indication this 

may be Bellerophon sp.; 996, one, slight indication this may 

be Bellerophon sp.; 10870, one. Sadlerochit formation: USGS 

locality 7118b (green), one, probably a bellercphontid, form 

approaches Bellerophon sp., but collection is krown to be of
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 133

Permian rather than Mississippian age. Unnamed Permian 

formation: USGS locality 11823, one, similar to BeUerophon 

sp., but collection is known to be of Permian rather than Mississippian age.

Superfamily EUOMPHALACEA

Family EUOMPHALIDAE 

Genus STRAPAROLLTTS Montfort, 1810 

Submenus EUOMPHALTTS Sowerby, 1814

Straparollus (Euomphalus) brooksensis Yochelson and Dutro,

n. sp.

Plate 12, figures 15, 20-23

Description. Low-spired euomphalids having a 

sharp upper angulation and rounded umbilical whorls; 

juvenile whorls well rounded and discoidal, sutures 

impressed only in this growth stage; mature shell low 

spired with body whorl embracing penultimate whorl 

at periphery; upper whorl surface flattened, inclined 

upward nearly 10° from horizontal in early growth 

stages, nearly horizontal to upper shoulder at maturity; upper shoulder angulated in most growth 

stages but not bearing a carina, the angulation becoming less distinct with age so that large specimens 

show a differentiation of upper and outer whorl faces 

but no sharp angulation; outer whorl face distinctly 

arched with periphery near midwhorl, becoming 

steeper and with a lower periphery in the gerontic 

stage; basal whorls well rounded in all growth stages, 

the profile following the arc of a circle from outer 

whorl face to umbilicus; umbilical sutures distinct; 

growth lines gently prosocline on upper whorl surface, gently prosocline to orthocline from upper angulation to periphery, seemingly gently prosocline below on outer whorl face, on basal whorl surface and 

up into umbilicus.

Discussion. The low spire, relatively large size, and 

rounded umbilical whorls differentiate Straparollus 

(Euomphalus) ~brooksensis from other Alaskan Euomphalidae. Several specimens bridge the gap from 

the discoidal earliest stages to the low-spired adult. 

In view of the long stratigraphic range of this form, 

it may very well be that more than one species is 

included. The number of specimens is so small and 

preservation is such that attempts to differentiate 

Lower Mississippian from Upper Mississippian forms 

have been unsuccessful. Pending study of additional 

specimens, it is assumed that this is a single species.

Several incomplete specimens have been tentatively 

referred to the species. These are indicated by the 

reference to footnote 2 in the proper column of the 

distribution chart (table 1).

Numerous low-spired euomphalids with rounded 

whorls have been named, particularly in European 

literature. Until these named forms have been systematically restudied, no comparison between them 

and S. (Euo<m,pkalus) brooksensis is warranted.

Illustrated specimens. Holotype: USNM 136515, USNM 

locality 3186; paratypes: USNM 136514, USGS locality 11890, 

and USNM 136513, USGS locality 13235.

Measurements. Measurements of the illustrated specimens 

(in mm) are given below:

Height of Width of 

Specimen Height Width aperture aperture

USNM 136513___-_--_-_ 5.4 13.0 ______ ____ 

136514_________- » 23 41.7 14.6 ' 16

136515__________ 10.7 21.0 __..__ -------

1 Estimated.

Occurrence and abundance. Wachsmuth limestone: USNM 

locality 3107, one; 3091, cf. one. Lower Mississippian undifferentiated: USGS locality 11890, one; 13235, two; 13240, cf. 

one. Alapah limestone: USNM locality 3087, two; 3186, one.

Straparollus (Euomphalus) alaskensis Yochelson and Dut~o, n. sp. 

Plate 12, figures 10-14, 16-19

Description. Very low spired euomphalids with 

nearly vertical umbilical walls; sutures distinc*, relatively deep in early growth stages; nucleus and juvenile whorls discoidal with rounded whorls, the upper angulation being poorly developed on largest 

juvenile whorl; mature whorl produced downward 

slightly so that it embraces penultimate whorl above 

midwhorl; upper whorl surface distinctly flattened, 

inclined 5°-10° from horizontal to a sharp, distinct, 

noncarinate outer angulation, the inclination of the 

upper whorl face increasing with age; outer whorl 

face inclined outward and downward following a concave outward curve for the upper one-third cf face, 

the lower edge of the curve being at the periphery, 

below which the outer whorl face is inclined inward 

20°-30° from vertical for most of distance below the 

periphery, curving more strongly near base; basal 

whorl face distinctly flattened, set off from the umbilicus by a sharp circumbilical angulation in all except the late mature and gerontic stages; umbilical 

walls turning abruptly from circumbilical angulation 

to nearly vertical; umbilicus wide and relatively deep 

for size and height of shell; growth lines gently prosocline from suture to upper angulation, on outer whorl 

face very gently opisthocline to periphery, there turning to prosocline and continuing straight down the 

lower part of the face across the base and into the 

umbilicus.

Discussion. The nearly vertical walls of the umbilicus readily distinguish Straparollus (Euomphalus) 

alaskengi-s from other known Permian species. The 

umbilical walls are even steeper than those of IS. 

(Euomphalus} levicarinatus Yochelson from the middle Permian of the southwestern United States (1956.
134 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

p. 217). Most cross sections do not appear to show 

the two shell layers characteristic of the family 

(Knight, 1934, pi. 26), but they can be observed on a 

few of the well-preserved specimens. The seeming 

lack of an outer shell layer, coupled with the poor 

development of the upper angulation in the earlier 

growth stages, suggested at first that specimens were 

only subinternal molds, that is, specimens lacking the 

outer shell layer. Subsequent finding of large specimens with a reasonably well developed upper angulation ruled out this possibility.

As in the case of other species described herein, 

some poorly preserved specimens have been tentatively 

referred to this species. These are distinguished by 

reference to footnote 2 in the appropriate column of 

the distribution chart (table 1).

Illustrated specimens. Holotype: USNM 136512, USGS 

locality 11823; Paratypes: USNM 13651 la, 136511b, and 

136511c, USGS locality 11814.

Measurements. Measurements of three of the illustrated 

specimens (in mm) are given below:

Specimen

USNM 136511b_ 

136511c136512_-

Height of Width of 

Height Width aperture aperture

6. 0 14. 1

6. 0 13. 9

12 27. 7

5. 0 

9. 1

5. 1

Occurrence and abundance. Siksikpuk formation: USGS 

locality 11785, six; 11814, twelve; 11816, seven; 14099, four, 

14152, nine; 11786, cf. three; 15453, cf. four. Sadlerochit 

formation: USGS locality 15813, one. Unnamed Permian 

formation: USGS locality 11823, one. ?Permian: USGS locality 982, one.

Straparollus (Euomphalus) sp. 

Plate 12, figures 24-26

Discussion. A third species of Euom-phalus in the 

Alaskan collections differs from the other two in being discoidal, with the earliest whorls depressed rather 

than low spired. The upper whorl surface is distinctly inclined upward to a carina on the outer 

angulation. The outer whorl face is slightly crushed 

in the specimen, but it appears to be arched outward 

to the periphery, located below midwhorl, and then 

less strongly curved inward to a basal angulation. 

Below this angulation, the basal whorl surface is flattened, except near the wide shallow umbilicus. The 

umbilical walls are steep, but no circumbilical angulation is present; the juncture with the basal surface is 

smoothly rounded. Growth lines are orthocline on the 

upper surface, essentially radial from the suture. On 

the outer whorl face they are gently opisthocline to 

the periphery, prosocline below, and finally straight, 

gently prosocline on the basal surface.

It does not seem appropriate to give a formal name 

to this single specimen. In some respects, particularly in the character of the umbilicus, this species is 

similar to Straparollus (Euomphalus) crateriformis 

(Koninck) from the Tournaisian of Belgium, but in 

that species the base is distinctly wider than the upper surface. A second incomplete small specimen has 

been tentatively referred to this species.

Illustrated specimen. USNM 136516, USGS locality 14954.

Occurrence and abundance. Wachsmuth limestone: USGS 

locality 14954, one. Alapah limestone: USGS locality 997, cf. 

one.

Genus AMPHICAPHA Knight, 194fl 

Subgenus CYLICIOSCAPHA Yoehelson, 1956

Amphiscapha (Cylicioscapha) grada Yochelson and Dutro, n. sp. 

Plate 12, figures 27-29

Description. Discoidal euomphalids w; th a shelf on 

outer whorl face and a prominent basal angulation; 

juvenile whorls rounded, depressed slightly below general upper surface of shell; sutures impressed in all 

growth stages; upper whorl surface distinctly inclined, following a curve gently concave upward from 

suture to a carmate angulation at the cuter edge of 

upper surface; outer whorl face inclined outward and 

strongly downward below sharp carina for about onethird of its total width, then bending abruptly to 

nearly horizontal for a short distance, rext abruptly 

flexed downward forming a step in the profile of the 

outer whorl face; below this step the outer whorl face 

is gently arched outward for a short distance to the 

periphery which is located just below iridwhorl; below the periphery the face steadily curves inward to 

the base, there being some evidence that in later growth 

stages a shallow groove and essentially vertical segment of the face occur just above the basal angulation; 

basal angulation distinct, slightly more than 90°, noncarinate; basal whorl surface flattened, nearly horizontal, curving gently inward as umbilicus is approached, then bending more abruptly into nearly 

vertical-walled wide umbilicus without, however, developing a circumbilical angulation; growth lines 

drthocline, radial from suture across inner half of upper whorl face, then gently curving prorocline to angulation, being nearly straight opisthocline on upper 

part of outer whorl face, but straight gently prosocline below the shelf, across the base, and into the 

umbilicus.

Discussion. The characteristic "step" on the outer 

whorl face readily distinguishes members of this subgenus from specimens of Euomphalus. In detail, 

Amphiscapha (Cylicloscapha) grada is discoidal, 

rather than low spired as are Straparollus (Euomphalus) brooksensis and /S. (Eu&mphalus) alaskensi<s. In 

basal view it is most similar to S. (Euomphalus) sp.,
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 135

but the basal angulation of that species is sharper 

and the basal whorl surface somewhat more inclined. 

A. (Cylicioscapha} grada lacks the nodes or rugosities on the upper angulation that are characteristic 

of other described species of the subgenus.

Illustrated specimen. Holotype: USNM 1365IT, USGS locality 11823.

Measurements. Measurements of the illustrated specimen 

(in mm) are as follows: height, 5.1; width, 16.2; height of 

aperture, 5.2; and width of aperture, 5.0.

Occurrence and abundance. Sadlerochit formation: USGS 

locality 15829, one. Unnamed Permian formation: USGS locality 11823, three.

INDETERMINATE ETTOMPHALACEANS

Discussion. As in the case of the bellerophontaceans, many specimens referable to this superfamily 

are poorly preserved, but most of these are relatively 

more poorly preserved than are the bellerophontaceans. Accordingly, for less than one-third of these 

specimens is it possible to express an opinion as to 

what species they represent.

Occurrence find abundance. Kayak shale: USGS locality 

13219, one; 13245, one; 13247, one. Wachsmuth limestone: 

USNM locality 3100, one; 3279, six, may be Straparollus (Euomplialus) brooksensis; USGS locality 13286, one; 14074, one, 

may be a distinct species from any described or discussed 

above. Lower Mississippian undifferentiated: USGS locality 

11807, one; 11858, one; 11861, one, may be Straparollus (EitompJialus) brooksensis; 12701, one; 12785, three; 13234, two; 

13241, one; 14097, two, may be Straparollus (Euomplialus} 

brooksensis. Alapah limestone: USNM locality 30S7a, one; 

3167, one; 3169, one; 3188, two; USGS locality 976, four, may 

be Straparollus (Euomplialus) brooksensis: 1015, one, may be 

Straparollus (Euomplialus) brooksensis; 12355, one; 14151, 

two; 15430, two, may be Straparollus (Euomplialus) brooksensis; 15455, one, may be Straparollus (Euomplialus) brooksensis. Upper Mississippian undifferentiated: USGS locality 

971, one; 11799, one may be Straparollus (EuompJialus) brooksensis. Siksikpuk formation: USGS locality 11815, two. Sadlerochit formation: USGS locality 1010, three. Unnamed Permian formation: USGS locality 13215, one, may be Straparollus (Euomplialus) alaskensis. ?Permian: USGS locality 989a, 

one.

Superfamily PLEUROTOMARIACEA

Family SINUOPEIDAE

Subfamily TURBONELLININAE

Genus RHINEODERMA Koninck, 1883

Rhineoderma? sp. 

Plate 12, figure 34

Discussion. A single specimen is questionably referred to this genus. The specimen is compressed and 

its original shape cannot be determined. There is some 

indication that the peripheral selenizone acted as a 

zone of weakness during compression, because growth 

lines are prosocline from suture to edge of specimen 

and are seemingly orthocline below. The specimen is 

phaneromphalous. The upper surface is ornamented

by spiral lirae, six major ones being present with 

finer lirae intercalated. The ornament and the presumed low-spired conical shape suggest a possible reference to RJimeodemna.

Illustrated specimen. USNM 136520, USNM locality 3167. 

Occurrence and abundance. Alapah limestone: USITM locality 3167, one.

Genus TTTRBONELLINA Koninck, 1881

Turbonellina? lata Yochelson and Dutro, n. sp.

Plate 12, figures 30-33

Description. Beehive-shaped phaneromphalous gastropods with a strong circumbilical angulation; nucleus and earliest whorls planispiral, more mature 

whorls moderately high spired; sutures distinct, 

slightly impressed; outer whorl face inclined outward 

and strongly downward, gently arched throughout its 

length, the flattened nearly horizontal base being set 

off from the outer whorl face by a relatively r arrow 

well-rounded periphery, the angle between outer face 

and base approximately 60°; narrowly phaneromphalons, with steeply inclined circumbilical walls, the 

umbilicus being set off by a sharp circumbilical angulation; growth lines on upper part of outer whorl 

surface prosocline, nearly 15° from vertical, their course 

below not certainly known, but seemingly with a sinus 

on the periphery; shell polished and unornamsnted.

Discussion. This species has a flattened nucleus and 

general whorl shape similar to that of the type species 

Turbanenina lepida (Koninck) from the ViseXn of 

Belgium. It differs in being smooth rather than elaborately ornamented. In addition, there is some question as to the course of the growth lines in T.I. lata. 

Until better specimens are available, the generic placement of the species must be questioned.

Illustrated specimens. Holotype: USNM 136518, USGS 

locality 13235; paratype: USNM 136519, USGS locality 13234.

Measurements. Measurements of the illustrated specimens 

(in mm) are given below:

Specimen Height Width

USNM 136518-------------------------- 4.0 5.2

l36519-_-_--------_------------- 10 10

Occurrence and abundance. Kayak shale: USNM locality 

3095, one. Lower Mississippian, undifferentiated: USGS 

locality 13234, two; 13235, one.

Family RAPHISTOMATIDAE

Subfamily LIOSPIRINAE

Genus TREPOSPIRA Ulrich and Scofield, 1897 

Subgenus TREPOSPIRA TTlrich and Scofield, 1897

Trepospira (Trepospira) sp. 

Plate 13, figures 1-3

Discussion-. A single specimen referable to this 

subgenus has been found in the Siksikpuk formation.
136 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

It is low spired and has a sharp keel. Ornament consists of short lirae radial from the suture. Unfortunately, most of the rest of the shell surface is lacking 

and details of the selenizone and other ornament cannot be determined. It appears likely that the shell is 

missing from the base and that the specimen originally had the umbilicus filled with callus.

Illustrated specimen. TJSNM 136522, USGS locality 14174. 

Occurrence and abundance. Siksikpuk formation: USGS locality 14174, one.

Subgenus ANGYOMPHALTTS Cossmann, 1915

Trepospira (Angyomphalus?) sp.

Plate 12, figures 35, 36

Discussion. A second species of Trepospira, from 

the Mississippian, appears to have a true umbilicus. 

The single specimen is a juvenile and cannot be contrasted with the preceding species except in the character of the umbilicus.

Illustrated specimen. USNM 136521, USGS locality 11843. 

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 11843, one.

Family EOTOMARIIDAE 

Subfamily EOTOMARIINAE

Tribe MOURLONIDES 

Genus MOTTRLONIA Koninck, 1883

Mourlonia minuta Yochelson and Dutro, n. sp. 

Plate 13, figures 4, 5

Description. Turbiniform gastropods with colabral 

ornament and a wide raised selenizone on the periphery; nucleus unknown; body whorl embracing penultimate whorl at lower edge of selenizone; upper whorl 

surface inclined outward and downward, slightly more 

arched near the selenizone, below which the whorl 

surface curves more strongly inward than above so 

that the upper whorl surface is distinctly more inclined toward vertical than the lower; base anomphalous; growth lines prosocline from suture, approximately 30° from the vertical, proceeding straight 

for most of the distance across the upper surface, 

curving more strongly backward near the selenizone, 

opisthocline below the selenizone for a short distance 

then turning to nearly orthocline; selenizone relatively wide, unbordered, raised slightly above the general level of the whorl surface, and bearing numerous 

lunulae; narrow parietal inductura in the upper part 

of the columellar lip; colabral ornament consisting of 

low rounded lirae above selenizone, somewhat weaker 

below, the interspaces being twice the width of the 

lirae.

Discussion. The relatively wide raised selenizone 

distinguishes Mourlonia minuta from other pleurotomariaceans in the Alaskan faunas. The ornament 

appears to be somewhat finer than that of other species 

having strong colabral ornament. This slight difference may be a reflection of the small size of the specimens of M. 'minuta, compared to the other pleurotomariaceans described.

Mourlonia minuta appears to be slightly higher 

spired with less well rounded whorls tran other species referred to Mourlonm. More significantly, the 

selenizone of this species is also relatively wider than 

that of other species currently placed in the genus. 

Further study of additional material may show that 

this represents a distinct genus.

Illustrated specimen. Holotype: USNM 1F6523, USGS locality 11865.

Measurements. Measurements of the illustrated specimen 

(in mm) are as follows: height, 9; width, 8.6; height of aperture, 5.4; and width of aperture, 5.

Occurrence and abundance. Alapah limeston^: USGS locality 

11865, seven.

Mourlonia? reloba Yochelson and Dutr->, n. sp. 

Plate 13, figures 6-9

Description. Turbiniform gastropoda with globose 

whorls and a narrow, bordered selenizone at periphery; shell moderately high spired; whorls embracing 

at upper edge of selenizone, the line of contact lowering very slightly with increasing maturity; sutures 

gently impressed; whorls well rounded from suture to 

peripheral selenizone, being somewhat less rounded 

below; anomphalous; growth lines orthocline at suture but, after leaving suture, prosocline, about 30° 

from vertical along upper whorl face to near edge of 

selenizone where they bend a little more strongly 

backward, below selenizone opisthocline for a short 

distance then turning to gently prosocline and proceeding straight to base of columella; selenizone relatively narrow, with closely spaced lunulae, and bordered by lirae; a narrow parietal inductura present 

on upper part of columellar lip, unl*nown below; 

colabral ornament of strong lirae above selenizone, 

slightly finer below, with fine colabrr.l lirae intercalated near the columella, the ornairent becoming 

less prominent with age.

Discussion. Mmirl-onia^. reloba differs from other 

pleurotomariacean species described herein in having 

a narrow, bordered selenizone at the periphery and a 

globose whorl profile. The strong colabral ornament 

is not an important taxonomic character as several 

unrelated pleurotomariacean lineages possess similar 

ornamentation. Specimens from localities 11816 and 

15153, are poorly preserved; these have been referred 

tentatively to the species.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 137

The Mourlo-nm* rel-oba form of shell with its narrow selenizone and globose whorls may be a distinct 

phylogenetic line. A Mississippian specimen in the 

U.S. National Museum collections, from near Fort 

Gibson, Okla., is remarkably similar to the specimens 

illustrated. Revision of the genus must be delayed, 

however, until more well-preserved specimens are at 

hand. No previously described Permian pleurotomareans are known that are comparable to M. ? reloba.

Illustrated specimens. Holotype: USNM 136525, USGS locality 14169; paratype: USNM 136524, USGS locality 14169. 

Measurements. Measurements of the illustrated specimens

(in mm) are given below:

Height of Width of 

Specimen Height Width aperture aperture

USNM 136524 ______ ! 37 29 ! 22 17

______ i 20 17.0 i 14 11. 9

i Estimated.

Occurrence and abundance. Unnamed Permian formation: 

USGS locality 14169, four. Siksikpuk formation: USGS locality 

11816, cf. one; 15453, cf. one.

NODOSPIRA Yochelson and Dutro, n. gen.

Type species. Nodospira ortiata Yochelson and 

Dutro, n. sp.

Diagnosis. Moderately high spired ornamented 

pleurotomariaceans with a bordered peripheral selenizone and well-rounded whorls; shell moderately high 

spired, the body whorl embracing the penultimate 

whorl at the lower edge of the selenizone; whorls 

relatively well rounded, with periphery near midwhorl; concave selenizone on periphery bordered by 

strong flanges; distinct colabral lirae.

Discussion. The genus Mourlonm Koninck appears 

to be much in need of revision for, as presently interpreted, it includes species from Middle Ordovician 

through Permian in age. Nodospira is proposed in 

an attempt to separate some species from the Mourlonia complex. The well-rounded whorls and the 

selenizone bordered by distinct strong flanges serve to 

distinguish Nodospira from Mourlonm. The colabral 

lirate ornament of this genus is similar to that of 

Ptychomphalina Fischer, which has been placed, perhaps improperly, in the synonymy of Mourlonm. 

Nodospira differs from Ptychomphalina in having 

the selenizone at midwhorl rather than below, and in 

having well-rounded whorls.

In the literature examined, no species have been 

found that can be referred to this genus. Mourlonia.- 

like forms occur in most Mississippian faunas. That 

no previously described species can be attributed to 

this genus is a reflection of the inadequacy of published illustrations and a lack of comparative material for study.

Nodospira ornata Yochelson and Dutro, n. sp. 

Plate 13, figures 14-17

Description. Conical pleurotomariaceans with 

strong subsutural protuberances and pronounced colabral lirae; earlier whorls unknown; shell moderately high spired with body whorl embracing penultimate whorl at lower edge of selenizone; upper whorl 

surface distinctly arched from suture, turning 

abruptly to horizontal at periphery and forming a 

relatively wide flange marking the upper borc1<3!r of 

the selenizone; below the selenizone the whorl surface 

is well curved, the profile following a curve nearly 

the arc of a circle; anomphalous; outer lip gently 

prosocline almost to selenizone, then sweeping strongly 

opisthocline for a short distance below selenizone and 

then swinging to distinctly prosocline on most of 

basal surface; columellar lip reflexed with a thir\ narrow inductura; selenizone concave between strong bordering flanges; ornament of strong colabral lirae on 

upper whorl surface in all growth stages known, the 

lirae somewhat finer below the selenizone; strong 

closely spaced, elongate, subsutural protuberances periodically interrupting the smooth profile of the upper 

whorl surface.

Discussion. The presence of the subsutural protuberances immediately distinguishes Nodospira ornata from other large pleurotomariaceans. In addition, the selenizone is wider than in Mourlonial reloba, 

and is raised. Colabral lirae are thicker than on 

Benibescia'i inumbilicata, and the gross shape differs, 

with the body whorl of this species embracing 1 igher 

on the penultimate whorl. These same features, and 

the lack of an umbilicus, distinguish N. ornata from 

new genus? B.

Illustrated specimens. Holotype: USNM 136528, USGS locality 14150; paratype: USNM 136529, USGS locality 14150.

Measurements. Measurements of the illustrated specimens 

(in mm) are given below:

Height of Width of 

Specimen Height Width aperture aperture

USNM 136528__-------- 32 27.3 18.7 15.4

136529__._____ 57 51 l 37 28

i Estimated.

Occurrence and abundance. Alapah limestone: USGS locality 

14150, six; 12340, twenty-two; 12348, ten.

Genus SPIROSCALA Knight, 1945 

cf. Spiroscala sp. 

Plate 13, figure 10

Discussion. Two specimens are tentatively referred 

to this genus. The first shows a conical, relatively 

high spired form with a peripheral flangelike eelenizone. The second specimen, not illustrated, is mashed
138 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

and incomplete, but shows an eavelike overhang of the 

selenizone and an absence of ornament near the suture. 

Lack of ornament distinguishes these specimens from 

a Mississippian form in the collections referred to 

Ph ym ato pleura.

Dlustrated specimen. USNM 136526, USGS locality 1008. 

Occurrence and abundance. Sartlerochit formation: USGS 

locality 1008, one; 15826, one.

Tribe EOTOMARIIDES 

Genus BEMBEXIA Oehlert, 1888

Bembexia? inumbilicata Yochelson and Dutro, n. sp. 

Plate 13, figures 30, 31

Description. Large conical aiiomphalous gastropods with bordered selenizone forming periphery; 

earlier whorls unknown; sutures impressed; body 

whorl embracing penultimate whorl below periphery; 

upper whorl surface inclined outward approximately 

35° from vertical and gently inflated, turning abruptly 

to horizontal and forming the upper bordering flange 

of the selenizone at the periphery; whorl profile below 

selenizone inclined steeply downward for approximately one-half of its length, then curving more 

strongly inward to the aiiomphalous base; concave 

selenizone located on the periphery between strong 

bordering flanges, the upper flange overhanging the 

lower; lunulae faint; growth lines prosocline from 

suture, approximately 20°, bending more abruptly 

backward just above the selenizone, below the selenizone opisthocline for a short distance then curving to 

prosocline, about 20° from vertical, and continuing 

straight downward; columellar lip with a narrow iiiductura; ornament of impressed growth lines alone.

Discussion. Bembe.ciat imniibnieata appears to be 

most similar, superficially, to Tropidostropha Longstaff, 1912, but lacks both an umbilicus and pitting in 

the shell. It differs from Bembe.via larteti (MunierChalmas), the type species, in being higher spired and 

in having the upper flange of the selenizone, rather 

than the lower flange, at the periphery. Because the 

significance of these differences cannot now be evaluated, generic placement of the species is questioned.

In addition to gross shape, Bembex'm'l rnumbilicata 

differs from Alaskan specimens referred to Mourlo'ii'm 

in lacking strong colabral ornament. It lacks nodes 

on the upper surface as are found in Nodospira ornata. The species is most similar in shape to specimens referred to as New genus? B., and at one time 

the two forms were confused. They differ however 

in the nature of the umbilicus, B. '? inum'bilic'ata being 

clearly aiiomphalous.

The spire of the holotype is incomplete and the 

aperture is slightly crushed. No meaningful measurements of the species can be presented.

Illustrated specimen. Holotype: USNM 13"536, USGS locality 10SG2.

Occurrence and abundance. Alapah limestone: USGS locality 10802, two; 12779, three; 14151, one; 12342, one.

Genus GLABROCINGULUM Thomas, 1940 

Subgenus GLABROCINGTTLUM Thomas 1940

Glabrocingulum (Glabrocingtilum) sp. 

Plate 13, figures 11-13

Discussion. This species is represented by two 

specimens from the Siksikpuk formation. They are 

moderately low spired, conical, and have the selenizone located at the periphery. The upper whorl surface bears a row of coarse nodes at the suture and at 

least three rows of fine nodes. The narrow selenizone is concave and bordered by shan lirae. The 

arched basal surface bears at least seven spiral carinae, 

all of which are noded. The base is aiiomphalous. 

The species does not warrant specific naming in view 

of the small number of specimens available.

Illustrated specimen. USNM 136527, USGS locality 14174. 

Occurrence and abundance. Siksikpuk formation: USGS 

locality 14174, two.

Subfamily NEILSONIINAE 

Genus NEILSONTA Thomas, 194C

Neilsonia? sp. 

Plate 13, figure 25

Discussion. Two collections from northern Alaska 

contain small, moderately high spired pleurotomariceans. All are poorly preserved, but enough remains 

of the shell to show the main features. The upper 

surface is distinctly inclined, but little arched. The 

selenizone forms the outer whorl face and is nearly 

vertical, the lower edge being at the periphery. The 

selenizone proper is concave and distinctly bordered. 

Below the selenizone the basal whorl surface is nearly 

straight, inclined inward for a distance about the ~ ^

width of the selenizone, at which place there is a 

distinct though slight angulation, below which the 

basal whorl surface curves inward and strongly 

downward. The base is aiiomphalous. The columellar lip is slightly reflexed. The upper whorl surface 

appears to have strong colabral ornament. No specimen is complete enough to show all the details 

given above, and a formal name does not appear 

justified.

Illustrated specimen. USNM 136533, USGS locality 9184. 

Occurrence and abundance. Alapah limestone: USGS locality 9184, fifty; 10868, twenty five.
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 139

Family PORTLOCKIELLIDAE 

Genus PORTLOCKIELLA Knight, 1945

Portlockiella ? sp. 

Plate 13, figures 18, 19

Discussion. A single specimen is questionably 

placed in this genus. It is a low-spired, relatively 

wide form. The specimen is either narrowly phaneromphalous or pseudoiimbilicate. Ornament consists 

of five widely spaced, low, spiral carinae. A selenizone 

probably occurs just below the last carina, below midwhorl, but just above the periphery. Growth lines, 

however, are not clear. On the base, below this presumed selenizone, ornament consists of revolving lirae, 

the exact number not determinable.

Illustrated specimen. -USNM 136530, USNM locality 3167. 

Occurrence and abundance. Alapah limestone: USNM locality 3167, one.

Family GOSSELETINIDAE

Subfamily GOSSELETININAE

Genus GOSSELETINA Fischer, 1885

Gosseletina? sp. 

Plate 13, figures 20, 21

Discusswn. A single specimen is characterized by 

a narrow selenizone high on the whorl, a distinctive 

feature of Gosseletina. The selenizone is concave and 

strongly bordered. Below the selenizone the whorl is 

ornamented by numerous spiral lirae. Whorls are 

moderately rounded and the specimen is relatively 

high spired for a pleurotomariacean. Except in the 

position of the selenizone, none of the features described are found on the low-spired smooth type species of Gosseletina. It may be that this form represents a new genus but, as with many of the specimens 

discussed, formal systematic treatment must be deferred until more specimens are available.

Illustrated specimen. USNM 136531, USGS locality 13236. 

Occurrence and abundance. Lower Mississippian umlifferentiated: USGS locality 13236, one.

Family PHYMATOPLETTRIDAE 

Genus PHYMATOPLETTRA Girty, 1939

Phymatopleura sp. 

Plate 13, figures 22-24

Discussion. A single well preserved specimen of 

Phymatopleura was collected from the Lower Mississippian. It shows the characteristic conical shape with 

a narrow, bordered, peripheral selenizone. The flattened base is ornamented by six revolving lirae. Ornament of the upper whorl surface is unusual in 

showing pronounced ontogenetic change. The penultimate whorl and earlier whorls bear five sharp spiral

lirae. The body whorl, on the other hand, is smooth 

except for growth lines and a noded subsutural lira.

Illustrated specimen. USNM 136532, USGS locality 13234. 

Occurrence and abundance. Lower Mississippian und !fferentiated: USGS locality 13234, one.

Family uncertain

New genus? A 

Plate 13, figures 26-28

Discussion. A new genus of pleurotomariaceans 

may occur in the Wachsmuth limestone. It is represented by a single distorted specimen and, therefore, 

the taxon is not formally named. The specimen does 

show several interesting morphological details.

The shell is conical and moderately low spirei, and 

has a peripheral selenizone located well below midwhorl. Sutures are distinct and impressed. Because 

of distortion the shape of the upper whorl surface 

cannot be determined with certainty, but it appears 

to have been essentially flattened from near the suture almost to the selenizone. The selenizone is narrow, raised and rounded, strongly convex outward. 

Below the periphery, the basal surface bends sharply 

inward. The base is anomphalous. Ornament consists of two elements, a series of short lirae Formal 

to the suture and fine threads normal to the growth 

lines. The intersections of these two sets form a 

reticulate pattern on the upper whorl surface. Growth 

lines are prosocliiie, about 30°, curving back more 

strongly near the selenizone. Below the selenizone, 

growth lines are orthocline, abruptly curving to prosocline on the base. In gross shape the specimen resembles Phymatopleura, but the convex selenizone of 

this specimen is distinctive. It is possible thrt this 

convexity is a result of distortion; more specimens 

are needed to determine this point. Phylogenetic position of this form within the Pleurotomariacea is 

most uncertain.

Illustrated specimen. USNM 136534, USGS locality T110. 

Occurrence and abundance. Wachsmuth limestone: USNM 

locality 3110, one.

New genus? B 

Plate 14, figures 26, 27

Discu-ssion. Two specimens from the unnamed Permian formation, may represent another new genus. 

One specimen is exceedingly fragmentary. Tl ^ second, illustrated, was partially cleaned from r, very 

resistant matrix. This specimen is incomplete and the 

body whorl has been offset by a small fracture.

The specimens are quite similar to Bembexial inumbilicata. They appear to be slightly lower spired, 

and have the body whorl embracing lower on the 

penultimate whorl. As there are only slight differ-
140 SHORTER CONTRIBUTIONS TO GENERAD GEOLOGY

ences between the two forms, incomplete specimens 

could be readily confused. They differ in that this 

form has a depression in the base. Unfortunately, it 

cannot be determined if a true umbilicus is present. 

There is some similarity to the Mississippian genus 

Tropidostropha Longstaff, 1912, but comparisons must 

be delayed until more complete specimens are available. So far as is known, this occurrence is unique 

in the Permian.

Illustrated specimen. USNM 136551, USGS locality 13215. 

Occurrence and abundance. Unnamed Permian formation : 

USGS locality 13215, two.

INDETERMINATE PLEUROTOMARIACEANS

Discussion. Numerous poorly preserved specimens 

can be referred to the Pleurotomariacea. Some few 

can be placed questionably in the taxa previously described. Others appear to represent additional genera 

and species too poorly preserved to discuss in detail. 

Still others are so incomplete that they cannot be 

placed in any taxon satisfactorily.

Occurrence and abundance. Kayak shale: USGS 

locality 13222, one, identification as pleurotomariacean 

uncertain. Wachsmuth limestone: USNM locality 

3173, three, two genera present, one with spiral ornament suggestive of Rhiiwoderma.'l sp., the other moderately high with a conical shape and possibly a genus 

not otherwise recorded in the fauna. Lower Mississippian undetermined : USGS locality 11807, one, may 

be Phymatopleura sp. ; 12700, one, pleurotomariacean; 

12701, three, with spiral ornament suggestive of 

RJi,meodenna,\ sp. ; 12785, three, moderately low spired 

and ornamented by spiral lirae, possibly a genus not 

otherwise recorded in the fauna; 13234, one, identification as pleurotomariacean uncertain; 13235, two, two 

genera present, one a pleurotomariacean, the other, so 

incomplete that identification as pleurotomariacean is 

uncertain; 13236, one, identification as pleurotomariacean uncertain. Alapah limestone: USNM locality 

3167, five, two genera present, similar, respectively, to 

those listed for USNM locality 3173; USGS locality 

1014, one, with spiral ornament suggestive of Rhineoderma'* sp. ; 12084, two, may be Mourlonia, minuta. 

Upper Mississippian undifferentiated : USGS locality 

972, one, conical with sutures little impressed and ornamented by spiral lirae, possibly a genus not otherwise recorded in the fauna. ?Upper Mississippian: 

USGS locality 14947, thirteen, moderately high spired 

with a peripherial selenizone and colabral ornament, 

may be a genus not otherwise recorded in the fauna. 

Siksikpuk formation : USGS locality 15453, one, pleurotomariacean with spiral ornament on base. Sadlerochit formation: USGS locality 7118h green, three, 

possibly Mourlonial reloba,; 1009, one, pleurotomariacean; 1010, one, may be cf. Spiroscala sp.; 15817, 

one, doubtfully Mourlonial reloba,. Unnamed Permian 

formation: USGS locality 11823, one moderately high 

spired with a concave selenizone near periphery, and 

spiral lirae on base, possibly a genus not otherwise 

recorded in the fauna; 13216, one, may t*> Mourlonial 

reloba. Permian: USGS locality 982, one, pleurotomariacean; 987, four, two genera present, one moderately high spired with a vertical outer whorl face, a 

selenizone at the juncture of upper and outer whorl 

faces, and spiral ornament, and may be a genus not 

otherwise recorded in the fauna, the otrer, identification of pleurotomariacean uncertain.

Superfamily PLATYCERATACEJ!

Family HOLOPEIDAE 

Genus YTTNNANIA Mansuy, 1912

Yunnania sp. 

Plate 13, figure 29

Discussion. One specimen is placed in this genus. 

It is moderately high spired with the upper whorl 

surface flattened, inclined outward and d ownward; sutures are not impressed. The outer whorl face is 

nearly vertical, and the basal surface is flattened, inclined inward and more strongly downward. The 

specimen is anomphalous. Ornament consists of spiral 

lirae on all three whorl faces, there beirg at least ten 

on the body whorl. The specimen is a steinkern retaining only one small patch of shell which does not 

show growth lines. It may be that this species is 

actually a pleurotomariacean, but slight evidence suggests that the outer lip did not possess a slit.

Illustrated specimen. USNM 136535, USGS locality 12785. 

Occurrence and abundance. Lower Mississirnian undifferentiated: USGS locality 12785, one.

Family PLATYCERATIDAE

Genus PLATYCERAS Conrad, 1810

Submenus FLATYCERAS Conrad, 18*0

Flatyceras (Flatyceras) ,sp. 

Plate 14, figure 28

Discussion. The genus Platyceras has been divided 

into several subgenera (Knight, Batten, and Yochelson, in press), the typical subgenus being restricted to 

those forms which have at least the earliest whorls in 

contact. This feature can be shown with certainty only 

for two collections of specimens, one from the Lower 

Mississippian and one from the Upper Mississippian. 

Except for the earlier whorls, the specimens are poorly
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 141

preserved and in other respects are similar to those 

identified as P1atycera$ (Orthonychia) sp. As used 

here, the grouping of Platyceras (Platyceras) sp. probably has no biologic meaning.

Numerous species of Platyceras have been described, 

particularly from rocks of Mississippian age, but no 

synthesis of the family has been attempted. Individual variation is great and definitive work on Platyceras should properly discuss the host echinoderms of 

the several species. Additional species names would 

only further complicate study of this family.

Illustrated specimen. USNM 136552, USGS locality 14035.

Occurrence and abundance. Lower Mississippian undiffereiitiated: USGS locality 11807, three. Upper Mississippian undifferentiated: USGS locality 14035, five.

Subgenus ORTHONYCHIA Hall, 1843

Platyceras (Orthonychia) sp.

Plate 14, figures 17-19

Discussion. Orthonychia differs from the typical 

subgenus of Platyceras in having all growth stages, 

including the earliest, out of contact so that a mature 

specimen does not complete as much as one whorl. 

Specimens in nine of the collections preserve the earliest whorls, and in six others enough of the shell is 

preserved to indicate that it is unlikely that the early 

growth stages were coiled. Other incomplete specimens have been referred to this taxon as a convenience rather than having them listed separately as 

indeterminate platycerataceans.

Most of the specimens are tubelike, but a few are 

flattened, patelliform. None of the specimens is well 

enough preserved to warrant detailed description; almost all lack the aperture. A detailed study of the 

shape of the apertures of some specimens might reveal 

information about the host echinoderms (Bowsher, 

1956), but poor preservation makes this extremely unlikely.

The platyceratids show considerable individual variation because of their life, attachment to echinoderm 

calices. Variation results from the orientation of the 

gastropod on the calyx and the shape of the tegmen. 

Little is known of specific limits of platyceratids. The 

grouping used here probably does not reflect a biologically valid species. Orthonychia is of little value 

in dating rocks because it is known from beds of 

Devonian through Permian age.

Illustrated specimens. USNM 136544a, 136544b, USNM locality 3089; USNM 136545, USGS locality 9186.

Occurrence and abundance. Kayak shale: USNM locality 

3095, three; 3247, three; USGS locality 13231, six; 13238, two; 

13252, two; 13258, two. Wachsmuth limestone: USNM locality 3089, thirty three; 3100, one; 3113, one; 3173, two; 3279,

two; USGS locality 14965, two. Lower Mississippian undifferentiated: USGS locality 9186, one; 12773, one; 12785, two; 

12798, one; 13225, one; 13228, one; 13232, two; 1323", one; 

13237, two; 13254, four; 13292, one. Upper Mississippi undifferentiated: USGS locality 14984, one. Sadlerochit formation: USGS locality 1009, two. ?Permian: USGS locality 

960, one 979, one.

Superfamily MICRODOMATACEA

Family ELASMONEMATIDAE 

Genus ANEMATINA Knight, 1933

Anematina rockymontanum (Shimer)

Plate 14, figures 10-16

Loxonema rockymontanum Shinier 1926, Canada Geol. Survey 

Museum Bull. 42, p. 81-82, pi. 4, figs. 9a, b; 10.

Description . High-spired subtrochiform gastropods 

with a flattened outer whorl face; in early growth 

stages sutures distinct and impressed; outer whorl face 

straight, little arched in juvenile stages, with increasing age developing a low spiral ridge at suture, below 

which the whorl face is slightly concave to near midwhorl, becoming slightly convex to the periphery located low on the whorl, the overall face being strongly 

inclined downward; in maturity the whorl face gently 

but distinctly arched; below the periphery the whorl 

curving strongly and rather abruptly inward to base 

in early growth stages, the base itself being flattened 

to about 10° or 15° from horizontal, becoming slightly 

arched and less clearly set off from the upper whorl 

face with increasing maturity; base probably anomphalous but, doubtfully, minutely phaneromphalous; 

growth lines on outer whorl face straight, pro~ocline 

at about 15°, crossing periphery and forming a wide 

shallow sinus on the base; columellar lip rot reflexed; ornamented by numerous spiral lirae which 

are finer than the fine growth lines, the lirae becoming more obscure with increasing size; shell thin.

Discussion. The flattened outer whorl face and flattened base of the early growth stages, combined with 

the large size, mark this as a distinct species The 

type species, Anematina proutana (Hall), is characterized by extremely small size and by rounded whorls 

in all growth stages. Anematina, rocky?nor,tamum 

(Shimer) seems to be closely related to A. laqueata 

(Koniiick) from the Visean of Belgium, but differs in 

lacking a spiral ridge on the base.

Through the kindness of Dr. Hans Frebold, Chief 

of the Section of Stratigraphic Palaeontology, Geological Survey of Canada, we were able to examine 

H. W. Shimer's original specimens of Loxonema rovkymontanum (Shimer, 1926, p. 81). Geological Survey 

of Canada No. 5093 is the holotype, the original of
142 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY

Shimer's figures 9a and 9b. Geological Survey of 

Canada No. 5093a is a figured paratype, the original 

of Shimer's figure 10. The specimens were numbered 

some years after the original description was published. Four additional specimens are included in 

5093. They are poorly preserved but may belong to 

this species. Shinier also studied two specimens from 

lot 5095, an associated locality. These are so poorly 

preserved that they cannot be referred even questionably to this species. With the exception of one natural cross section, all of Shimer's specimens were broken from limestone.

There is no doubt that the specimens from northern 

Alaska are conspecific with Shimer's species. The 

close similarity between the types and the Brooks 

Range material is illustrated on plate 14. Unfortunately, many of the Alaskan specimens have been distorted. Others are incomplete or are steinkerns. This 

less well preserved material is only tentatively referred to the species.

Small steinkerns of Anematina can be separated 

from those of Loxonema by two characters. First, 

the more angular whorl face and flattened base are 

reflected in the steinkem; the profile of Loxon-ema is 

relatively well rounded. Second, the Anematina shell 

is thinner than that of Loxonema. This feature results in a relatively smaller gap between whorls of the 

steinkem.

In the holotype, the outer whorl face is flattened 

and set off rather abruptly from the flattened basal 

whorl surface. The slightly larger paratype, on the 

other hand, has a somewhat more rounded body whorl 

with the outer and basal faces distinctly arched and 

not so clearly separated. Although the whorl profiles 

of mature specimens of Loaconema and Anematina are 

not too dissimilar, the growth lines are fundamentally 

different. Poorly preserved specimens of the two 

genera could be confused.

Illustrated specimens. Holotype: GSC 5093; paratype: GSC 

5093a; hypotype: USNM 136542, USGS locality 13288; hypotype: USNM 136543, USGS locality 11808.

Measurements. Measurements of the illustrated specimens 

(in mm) are given below:

Specimen Height 

20.5

Width

1 10 

______ * 14

1 26 i 12 

1 14 5. 9

GSC 5093____________________________

5093a.__________________________

USNM 136542_ _______________________

136543________________________

1 Estimated.

Occurrence and abundance. Wachsmuth limestone: USNM 

locality 3098, one; 3173, cf. one; USGS locality 13278, one. Lower 

Mississippian undifferentiated: USGS locality 11808, two; 12785, 

one; 12701, cf. one. Alapah limestone: USNM locality 3182, 

one, 3272, one; USGS locality 13288, one; 9187, cf. two.

Anematina? sp.

Discussion. Ten high-spired specimens listed below 

are questionably placed in Anematina because of the 

poor quality of preservation. In spite of the present 

uncertainty it seems reasonable to suggest that further collecting will indicate that only a single species 

of the genus is present in Mississippian rocks of 

northern Alaska.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 13242, one. Alapah limestone: USNM 

locality 3167, one; USGS locality 1014, one. Upper Mississippian undifferentiated: USGS locality 975, seven.

Superfamily ANOMPHALACEA

Family ANOMPHALIDAE 

Genus ANOMPHALTTS Meek and Worthier. 1867

Anomphalus sp. 

Plate 14, figures 7-9

Discussion. One small well-preservec1 rotelliform 

gastropod is placed in this genus. The shell surface 

is typically polished and smooth except for two faint 

spiral lirae near the suture. Sutures are impressed. 

Growth lines are gently opisthocline on the upper 

surface to nearly halfway between suture and periphery, where they swing backward becoming distinctly 

prosocline on the lower part of the outer whorl face. 

The umbilicus is relatively wide and seemingly without any sort of an inductural constriction or filling, 

although preservation is such that the possibility of a 

pseudoumbilicate condition cannot be ruled out.

The species lacks the short radial ornament at the 

suture which apparently characterizes Anomphalus 

nerviensis Koninck, from the Lower Carboniferous of 

Belgium.

Illustrated specimen. USNM 136547, USNM locality 3167. 

Occurrence and abundance. Alapah limestone: USNM locality 3167, one.

Superfamily NEBITACEA

Family NERITOPSIDAE

Subfamily NATICOPSINAE

Genus NATICOPSIS M'Coy, 1844

Subgenus NATICOPSIS M'Coy, 1844

Naticopsis (Naticopsis) suturicompta Yochelson and Dutro, n. sp. 

Plate 14, figures 20-25

Description. Well-rounded neritopsic's with ornament on a subsutural ramp developed ir intermediate 

growth stages; sutures distinct, becoming more impressed with age; shell low spired, the body whorl 

embracing the penultimate whorl above the periphery; 

whorls relatively well rounded, "apple shaped," a narrow subsutural ramp in all intermediate growth 

stages, followed by a smooth curve which near the
LATE PALEOZOIC GASTROPODA FROM NORTHERN ALASKA 143

periphery approaches the arc of a circle, and a slight 

elongation of the whorl below the periphery; growth 

lines straight, gently prosocline from suture to columella; inductura and other apertural features unknown; ornamented by distinct subsutural lirae which 

appear after the earliest growth stages, coincident ally 

with the development of the subsutural ramp, and 

disappear at maturity simultaneously with disappearance of the ramp.

Discussion. The subsutural ornament' of Naticopsis (Naticopsis) suturicompta is similar to that of 

species referred to N. (Jedria) Yochelson, 1953. The 

relatively high-spired, elongate shape of the latter, 

however, is quite distinct from the well-rounded "apple shape'' of the typical subgenus. As closely as can 

be determined, this combination of well-rounded 

whorls and subsutural ornament is confined to this species. Certain American and Belgian species approach 

the shape of N. (Naticojms) suturicompta, but ornament either is not present or was overlooked and not 

figured by earlier workers.

This species characterizes the " Naticopsis howi zone""1 

of Dutro and Bowsher (1957") and is the same form 

referred to by them.

Partially exfoliated specimens show the presence of 

two shell layers. They also show, on the inner layer, 

growth lines parallel to those on the outer layer. 

These lines have not been observed on silicified specimens from the Permian of west Texas. Kather, the 

inner shell layer of those forms is characterized by 

structures essentially normal to the growth lines.

As with most of the gastropods from northern 

Alaska, preservation of specimens presents problems 

with the taxonomic treatment. The type of this species and a few other smaller specimens show the characteristic ornament. Most of the specimens do not 

preserve the early whorls or, if they are present, they 

are partially exfoliated or are steinkerns. However, 

in these specimens the shape of the mature body whorl 

agrees closely with the type. The alternatives of regarding these less well preserved specimens as a separate species or only tentatively comparing them to this 

species have been considered but rejected, and all Upper Mississippian specimens of fair preservation are 

placed in one species.

Several specimens from the Lower Mississippian are 

tentatively referred to the species. These are all small 

nearly globular shells possessing subsutural ornament 

but lacking a subsutural ramp. Some neritacean species are known to undergo considerable ontogenetic 

change. Further collections may show that the mature stage of these Lower Mississippian forms distinguishes them from the Upper Mississippian species. 

If they do represent another species, it would indicate 

that ornament alone is an unreliable criterion for identification of poorly preserved or immature specimens.

Illustrated specimens. Holotype: USNM 136549, USGS locality 9187; paratypes: USNM 136548, USNM locality, 3088; and 

USNM 136550, USNM locality 3170.

Measurements. Measurements of the illustrated specimens 

(in mm) are given below:

Height of Width of 

Specimen Height Width aperture aperture

USNM 136548---------- 1 55 55 47 43

136549_-___._--_ 26 24 20 16 

136550.-._..--_- '25 26 20 18

i Estimated.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 11808, cf. one; 12701, cf. one; ir240, cf. 

two. Alapah limestone: USNM locality 3088, twenty; 3164, 

one: 3170, two; 3171, one; 3182, cf. one; USGS locality 9187, 

three; 12355, three; 15430, one; 994, cf. one. Upper Mississippian undifferentiated: USGS locality 11799, three.

Naticopsis (Naticopsis) sp. 

Plate 14, figure 5

Discussion. A single small specimen from the Mississippian Lisburne group differs from juvenile specimens of Naticopsis (Naticopsis) suturicompta. It is 

markedly higher spired, and has an elongate, poorly 

rounded body whorl with the periphery well below 

midwhorl. No subsutural ramp is developed. The 

specimen has fainter subsutural ornament than is 

characteristic of N. (Naticopsis) suturicompta, but 

this may be a feature of immaturity. The specimen is 

too poorly preserved to warrant a formal specific name.

Illustrated specimen. USNM 136540, USGS locality 13235. 

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 13235, one.

INDETERMINATE NERITACEANS

Discussion. As with most of the other sup°,rfamilies treated herein, there are some specimens referable 

to the superfamily that are quite poorly preserved. 

Unlike the material from the other groups, most of 

these are not steinkerns, but are either distorted specimens or juveniles. It seems probable that most of 

these specimens are referable to Naticopsis in the broad 

sense. Specific identification is not possible.

Occurrence and abundance. Kayak shale: USGS locality 

13247, one. Wachsmuth limestone: USGS locality 132^6, one. 

Lower Mississippian undifferentiated: USGS locality 12701, 

eight; 12709, one; 12785, three; 12788, one; 13234, one; 13235, 

one; 13254, one; 13255, one. Alapah limestone: USGS locality 976, one; 997, one; USNM locality 3167, one. ?Upr^r Mississippian : USGS locality 13246, one.
144 SHORTER CONTRIBUTIONS TO GENERAL- GEOLOGY

Order MESOGASTROPODA 

Superfamily MURCHISONIACEA

Family MURCHISONIIDAE 

Genus MURCHISONIA Archiac and Verneuil, 1841

cf. Murchisonia sp. 

Plate 14, figure 1

Discussion. A single specimen is tentatively referred to this genus, as used in the broadest sense. 

The specimen is high spired, has impressed sutures 

and apparently well-rounded whorls. There is a spiral 

lira below the periphery forming what appears to be 

the lower border of a gently concave selenizone. The 

specimen is exceedingly poorly preserved, but it is 

unique in the fauna and has been figured.

A second, even more poorly preserved specimen is 

questionably placed in this taxon.

Illustrated specimen. USNM 136537, USGS locality 13240.

Occurrence and abundance. Lower Mississippian undiffereiitiated: USGS locality 13240, one. Alapah limestone: USGS 

locality 9184, cf. one.

Family PLETHOSPIRIDAE

Subfamily PITHODEINAE

Genus PLATYZONA Knight, 1945

Platyzona sp. 

Plate 14, figure 2

Discu-ssion. This species, identified from a single 

specimen, is not named. The specimen is fairly well 

preserved, but is incomplete. The shell is moderately 

high spired. Sutures are impressed and whorls are 

relatively broad and well rounded, being flattened near 

the suture. A broad concave selenizone is located on 

the periphery. Growth lines on the upper whorl surface are prosocline, sweeping backward from the suture to the selenizone. Below the selenizone they are 

gently opsithocline for about the upper third of the 

lower whorl surface. Details of the aperture and base 

are unknown.

Illustrated specimen. USNM 136538, USGS locality 13246. 

Occurrence and abundance. ?Upper Mississippian: USGS 

locality 13246, one.

INDETERMINATE MURCHISONIACEANS

Discussion. Four specimens are placed in this 

grouping. The first is a steinkern retaining patches 

of shell. The other three are incompletely silicified 

shells.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 13240, one, whorls ornamented by several spiral lirae; more angular than cf. Murcliisonia sp. Alapah limestone: USNM locality 3167, one, may show evidence 

of a selenizone; 3272, two, may show evidence of a selenizone.

Superfamily LOXONEMATACEA

Family LOXONEMA.TIDAE 

Genus LOXONEMA Phillips, 1841

Loxonema sp. 

Plate 14, figure 6

Discussion. Specimens referred to this species are 

typical of the genus. They are exceedingly high 

spired, have deep sutures and well-rounded whorls. 

Growth lines are arcuate, forming a wide, quite shallow sinus, the most posterior portion of which is near 

midwhorl. This sinus distinguishes the specimens 

from those called cf. Murchisonia sp. All the specimens are small and it is assumed that they are immature.

Illustrated specimens USNM 136541, USGS locality 11828. 

Occurrence and abundance. Alapah limestone: USGS locality 11828, three.

INDETERMINATE LOXONEMATACHANS

Discussion. Specimens placed here are poorly preserved steinkerns. It should be pointed out that reference to cf. MurcMsonm sp. would be nearly as feasible, because either of these fundamentally different 

shells, when exfoliated, produce almost identical steinkerns.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 9186; two, possibly Loxonema,; 13235, 

five, four to five times size of specimens of Loyonema sp.; 

Alapah limestone: USGS locality 976, seven, doubtfully Loxonema.

Order NEOGASTROPODA 

Superfamily STTBULITACEA

Family SUBUIITIDAE

Subfamily SOLENISCINAE

Genus IANTHINOPSIS Meek and Wortlen, 1866

lanthinopsis? sp. 

Plate 14, figure 3

Discussion. Two specimens from the Lower Mississippian show the low-spired subglobular shape characteristic of some of the soleniscinids. They are questionably placed in lanthinopsis, this being the most 

common upper Paleozoic genus. Keith?r shows features of the columellar lip, critical fc1** more exact 

placement. The specimens are in part exfoliated; the 

rest of the shell has been recrystallized.

Illustrated specimen. USNM 136539, USGS locality 12785. 

Occurrence and abundance. Lower Mississipnian undifferentiated: USGS locality 11867, one; 12785, one.

Glass SCAPHOPODA

Genus indeterminate

Plate 14, figure 4

Discussion. A single, incomplete scaphopod is present in the collection from USGS locality 13246. Faint
LATE PALEOZOIC GASTROPODA PROM NORTHERN ALASKA 145

traces of annular growth lines can be seen, but if other 

ornament was originally present, it is not preserved. 

The specimen does not warrant description and is included here only because Mississippian scaphopods are 

relatively rare and occurrences should be recorded. A 

second specimen from TJSGS locality 13240 seems to 

lack transverse ornament, and in that respect is similar to PT.agioglypta Pilsbry and Sharp (1897).

Illustrated specimen. USNM 136546, USGS locality 13246.

Occurrence and abundance. Lower Mississippian undifferentiated: USGS locality 13240, one. ?Upper Mississippian: 

USGS locality 13246, one.

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Geol. and Nat. Hist. Survey, final rept. 3, pt. 2, p. 813-

1081, pis. 61-82. 

U. S. Department of Defense, 1953-1957, Arctic bibliography:

v. 1-7. 

Warthin, A. S., Jr., 1930, Micropaleontology of the Wetumka,

Wewoka, and Holdenville formations: Oklahoma Geol.

Survey Bull. 53. 

Yochelson, E. L., 1953, Jedria a new subgenus of Naticopsis:

Washington Acad. Sci. Jour., v. 43, p. 65. 

_____ 1956, Permian Gastropoda of the southwestern United

States: [pt.] 1. Euomphalacea, Trochoneinrtacea, Pseudophoracea, Anomphalacea, Craspedastomatacea, and Platyceratacea: Am. Mus. Nat. History Bull., v. 119, p. 173-

276, pis. 9-24.
INDEX

[Italic numbers indicate descriptions]

Page 

Acknowledgment _ --------- ...-... 113

Alapah limestone...------------- 113,116,117,118

alaskensis, Straparollus (Euomphalus)___ . 115,

116,117,118,119, 133, 134, pi. 12

Amphiscapha.---------------------------------- 121

(Cylicioscapha) grada--.- 116,117,118,119, 134, pl.12 

analoga, Leptaena......------ --------- .__ 115

Anematina lagueata.....-..-.-.-......--........ 141

proutana... -_-_- _---._ - - _- 141

rockymontanurn......-_.-_ 116,117,118, 141, pl. 14

sp_.------------------------ 116,117,118,140

(Angyomphalus), Trepospira. -__. 116,117,136,pi. 12 

Anomphalidae ---------------------- _ 142

Anomphalus nerviensis..-..--------------------- 142

sp - - ------- - --- 116,117,118,142, Pi. 14

asiaticum, Lithostrotion.....--------------------- 115

Bellerophon giganteus--.---------- ---------- 132

sp........ --------- 116,117,118, 131, pi. 12

Bellerophontaceans -.--.-_---.__ 116,117,118,119 

Bellerophontidae. _-__-_------.--.--.-_------- 131

Bellerophontinae_ __---_-..___.-._--__ 131 

Bembexia inumbilkata.. 116,117,118,137, 138, 139, pi. 13

larteti. . - - - 138 

Brachythyris suborbicularis.-.................... 115

zone_____---.__-____--_--.__ 115,116 

Brooks Range._--__-_.__--------- 111,113,115

brooksensis, Straparollus (Euomphalus)..... _-_-_ 116,

117,118,133,134, pi. 12

Canning River district.-- _______...._ 111

crateriformis, Straparollus (Euomphalus)-------- 134

crenistria, Goniatites.....------------------------ 115

(Cylicioscapha) grada, Amphiscapha... .......... 116,

117,118,119, 134, Pl. 12

Elasmonematidae---- - - __-_ __ _ 141-142

Eotomariidae.- __ ._____.......... 136

Eotomariinae...-- -------___------_-_ ----- 136

Euomphalaceans-.______.__... 116,117,118,119 

Euomphalidae---- _- ---- --_---------___-_- 133

Euomphalus ---------- -_ -_ - _ -- 134

(Euomphalus), Straparollus.-_..... 116,117, 1S4, pl. 12

alaskensis, Straparollus...___-_------__-.. 115,116,

117,118,119, 1SS, 134, pl. 12

brooksensis, StraparoHus_............... 116,117,

118, 133, 134, pl. 12

crateriformis, Straparollus.------... ..._... 134

leeicarinatus, Straparollus.------------------ 133

Euphemites sp. .......... 116,117,118, 131, 132, pl. 12

Euphemitinae_--- __.__--------- 131

giganteus, Bellerophon..... -___ _ . 132

Glabrocingulum (Glabrocingulum) sp_-....-.. 116,117,

119, 138, pl. 13 

(Glabrocingulum), Glabrocingulum....-------- 116,117,

119,138, pl. 13 

Goniatites crenistria. ----_- _- __ 115

zone.. - ---__------__-_----_--. 115,117,118

Gordon, Jr., Mackenzie, quoted..-_---------- 115

Gosseletinasp-.....-___...__.. 116,117, 139, pl. 13

Qosseletinidae-...---------- --...-__-_- .._-. 139

Gosseletininae__.____..-.-.____......_ 139

grada, Amphiscapha (Cylicioscapha)--.......- 116,117,

118,119,134, pl. 12

Pags

Holopeidae...--------------------------------.. 140

howi, Naticopsis---------.---.......--.------.-. 115

Naticopsis zone................... 115,117,118,143

lanthinopsissp..................... 116,117,144, pl. 14

inumbilkata, Bembexia _-__ __--__ _ 116,117, 

118,137, 138, 139, pl. 13

(Jedria), Naticopsis.................. -_-_. 143

Kayak shale- ----.-------.---__--._-_- 113,115,116

Knight, J. Brookes, ()uoted.-.___............. Ill

Knightites (Retispira) sp............ 116,117, ISt, pl. 12

Knightitinae.._---.-.__._____ . 132

konincki, 7.aphrenth __..,-.--------------------- 115

laqueata, Anematina---------------------------- 141

larteti, Bembexia------------.................... 138

lata, 1 urbonellina .......... 113,116,117,118, 135, pl. 12

lepida, 1urbonellina...... _-._.___............. 135

Leptaena analoga--............................. 115

zone......__-------__-_-__......... 115,116

levicarinatus, Straparollus (Euomphalus)-------- 133

Licharewia .... .........--........-....-- .... 115

Liospirinae.-. _ .- _ - ____ __- 135

Lisburne group-_-...-.---.-...-.-.-.-.-...--- 113 

Lithostrotion asiaticum-------------------------- 115

zone-......---..-...---.-.-.--- 115,116,117,118

Loxonema rockymontanum.--------------------- 141

sp--------------------- 116,117,118,142, 144, pi. 14

Loxonemataceans__........................ 116,117

L ox otiemat idae -.-..----.-.---.-.---.-.-.. -- 144

minuta, Mourlonia--....... 116,117,118, 136, 140, pl. 13

Mourlonia_____._ _ _-. __-- 137,138 

minuta................. 116,117,118, 136, 140, pl. 13

reloba - 115,116,117,118,119, 136,137, 140, pl. 13 

Murchisonia sp__-_-__-__-._-__-_. 116,117, 144, pl. 14 

Murchisoniaceans _- -__ ........ 116,117,118

Murchisoniidae __ .... -.---.....-.-.-.------..- 144

Naticopsinae--. .------------- ----------- . 142

Naticopsis howi..-...-.-.-...-...........-----.. 115

(Jedria) ___ ..__ __._._._ 143

(Naticopsis) suturicompta-..-- 115,116,117,118, 14S 

sp . __ -- 116,117, 143, pl. 14

suturicompta... ............................. 119

zone-..----------.------. 115,116,117,118,119,143

(Naticopsis), Naticopsis-.--------- 116,117, 143, pl. 14

suturicompta, Naticopsis...... 115,116,117,118,142

Naval Petroleum Reserve No. 4_......-..-. . Ill

Neilsonia sp... ................. 116,117,118,138, pl. 13

Neilsoniinae....------ ........................ 138

Neritaceans--------_-.---------.-._.- 116,117,118,119

Neritopsidae--__-------____._____-.. 142

nerviensis, Anomphalus-- --.-.----.- --.-..-. 142

New genus A ----------------- 116,117, 139, pl. 13

B-_ _-__...-....-_---- 116,117,139, pl. 14 

Nodospira---.- --.---------------.-----------. 137

ornate..... .. 116,117,118, 137, 138, pl. 13

Opisthocline, defined- . -___ - 121

ornate, Nodospira........... 116,117,118, 137, 138, pl. 13

Orthocline, defined.................. ........ 121

(Orthonychia), Platyceras........... 116,117, 141, pl. 14

Page 

Pelmatozoan calyxes-......................... . 119

echinoderms_-.....-.........-.......... 115

Phymatopleurasp.----.-- 116,117,138,139,140, pl. 13

Phymatopleuridae ___- ._._...____.. 139 

Pithodeinae--_....__............_.___ 144

Pfapio^ypte-,---------------------------------- 145

Platyceras- --. _- .-- 115,116,117,118,119,140 

(Orthonychia) sp_._............. 116,117,141, pl. 14

(Platyceras) sp......... 115,116,117,118, 140, pl. 14

(Platyceras), Platyceras---- 115,116,117,118, /40,pl. 14

Platycerataceans-----... __--......_.-----.. 115,119

Platyceratidae__ - _-- _ - -. 140 

Platyzona sp--.. .... ....... 116,117,144, pl. 14

Plethospiridae --.-----,-------------------- 144

Pleurotomariaceans ..--____ 116,117,118,119,122 

Portlockiellasp .......... 113,116,117,118,139, pl. 13

Portlockiellidae --------------------------- 139

Prosocline defined - _- . - 121

proutana, Anematina.- _--- --- - -_ - 141 

Ptychomphalina.-...------------- ............ 137

Raphistomatidae. ......._---------_--.... 135

reloba, Mourlonia.--------------- ... - _ 115,

116,117,118,119, 136, 137,140, pl. 13 

(Retispira), Knightites.-............ 116,117,132, pl. 12

Rhineodermasp------ 113,116,117,118,135,140, pl. 12

rockymontanum, Anematina---- 116,117,118,141, pl. 14

Loxonema-................................. 141

Rugose corals_. - -- _. - Ill

Sadlerochit formation............. 113,115,117,118,119

Scalarituba sp.._----------------------------- 115

Zone--.-------...-.--.---------.---.---.- 115,116

Scaphopod, genus indet----------- 116,117,144,pl. 14

Siksikpuk formation...---------- 113,115,117,118,119

Sinuitidae.. __..__-_ -.-____ 131 

Sinuopeidae..- - -- - - _- 135 

Soleniscinae. __...__..-.. _.............. 144

Spiroscalasp................... 116,117,137,140, pl. 13

Stelnkerns..........---...--. -..-.-.-..-... 118

Straparollus---...... .....__.....__..... 119,121

(Euomphalus) alaskensis ------------------ 115,

116,117,118,119,133,134, pl. 12 

brooksensis--..-.... 116,117,118,133,134, pl. 12

crateriformis----- ...-------------------- 134

levicarinatus--..----------.------------- 133

sp.......................... 116,117,134, pl. 12

suborbicularis, Brachythyris...................... 115

Subulitldae........--....-.......---.---...- 144

suturicompta, Naticopsis-....................... 119

Naticopsis (Naticopsis) .-..- 115,116,117,118,145

Trepospira (Angyomphalus) sp.__ 116,117,136, pl. 12 

(Trepospira) sp............ 116,117,119,135, pl. 13

(Trepospira), Trepospira------- 116,117,119,135, pl. 13

Tropidostropha...... _ ._ - - 140

Turbonellina lata.-------- 113,116,117,118, 135, pl. 12

lepida....................................... 135

Turbonellininae._ _ -- ____-_----- 135

Visean formation.--............................ 115

Wachsmuth limestone --- _ -- 11?, 115,116 

Yunnaniasp --................. 116,117,140. pl. 13

Zaphrentis konincki..--------------------------- 115

zone.......... ......................... 115,116

147

PLATES 12-14
PLATE 12

FIGURE 1. Knightites (Retispiral) sp. (p. 132)

Oblique top view, X 2; USNM 136506, from USGS loc. 11843, Lower Mississippian. 

2-4. Euphemites sp. (p. 131)

2. Oblique front view, X 2; USNM 136507a, from USGS loc. 12084, Goniatites zone, Alapah limestone. Oblique top 

view and side view, respectively, X 2; USNM 136507b, from USGS loc. 12084, Goniatites zone, Alapah limestone. 

5-9. Bellerophon sp. (p. 131)

5. Side view of small steinkern, X 2; USNM 136508a, from USNM loc. 3088, Naticopsis zone, Alapah limestone.

6. Front view showing selenizone, X 2; USNM 136509, from USGS loc. 11799, Naticopsis zone, Alapah limestone.

7. 8. Side and top views, respectively, of a steinkern, X 1; USNM 136508b, from USNM loc. 3088, Naticopsis zone,

Alapah limestone.

9. Top view of a large steinkern, X 1; USNM 136510, from USGS loc. 15408, Naticopsis zone, Alapah limestone. 

10-14. StraparoUus (Euomphalus) alaskensis Yochelson and Dutro, n. sp. (p. 133) 

16-19. 10. Section showing two shell layers, < 2; paratype, USNM 136511a, from USGS loc. 11814, Siksikpnk formation.

11. Slightly oblique side view, X 2; paratype, USNM 136511b, from USGS loc. 11814, Siksikpuk formation. 

StraparoUus (Euomphalus) alaskensis Yochelson and Dutro, n. sp. (p. 133)

12-14. Side, top, and basal views, respectively, X 2; paratype, USNM 136511c, from USGS loc. 11814, Siksikpuk

formation. 

16-19. Side, apertural, basal, and top views, respectively, X 1; holotype, USNM 136512, from USGS loc. 11823,

unnamed Permian formation(?). 

15, 20-23. StraparoUus (Euomphalus) brooksensis Yochelson and Dutro, n. sp. (p. 133)

15, 20. Basal and top views, respectively, of small specimen, X 2; paratype, USNM 136513, from USGS loc. 13235,

Lower Mississippian.

21. Apertural view, X 1; paratype, USNM 136514, from USGS loc. 11890, Lower Mississippian. 

22,23. Side and top views, respectively, X 2; holotype, USNM 136515, from USNM loc. 3186, L>'thostrotior> zone,

Alapah limestone. 

24-26. Straparollus (Euomphalus) sp. (p. 134)

Top, basal, and apertural views, respectively, X 2; USNM 136516, from USGS loc. 14954, Brachythyris zone,

Wachsmuth limestone. 

27-29. Amphiscapha (Cylicioscapha^i grada Yochelson and Dutro, n. sp. (p. 134)

Side, top, and basal views, respectively, X 2; holotype, USNM 136517, from USGS loc. 11823, urnamed Permian

formation(?). 

30-33. Turbonellinat lata Yochelson and Dutro, n. sp. (p. 135)

30-32. Side, basal, and oblique top views, respectively, X 2; holotype, USNM 136518, from USGS loc. 13235, Lower

Mississippian.

33. Basal view, X 4; paratype, USNM 136519, from USGS loc. 13234, Lower Mississippian. 

34. Rhineodermal sp. (p. 135)

Top view, X 2; USNM 136520, from USNM loc. 3167, Lithostrotion zone, Alapah limestone. 

35-36. Trepospira (Angyomphalus?) sp. (p. 136)

Top and basal views, respectively, X 4; USNM 136521, from USGS loc. 11843, Lower Mississippian.
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PLATE 13

FIGURES 1-3. Trepospira (Trepospira} sp. (p. 135)

Basal, top, and side views, respectively, X 1; USNM 136522, from loc. USGS 14174, Siksikpuk(?) formation. 

4-5. Mourlonia minuta Yochelson and Dutro, n. sp. (p. 136)

Side, and top views, respectively, X 2; holotype USNM 136523, from USGS loc. 11865, Lisburne group (upper

formation). 

6-9. Mourlonia? reloba Yochelson and Dutro, n. sp. (p. 136)

6, 7. Side and basal views, respectively, X 1; paratype, USNM 136524, from USGS loc. 14169, unnamed Permian

formation. 

8, 9. Top and adapertural views, respectively, X 2; holotype, USNM 136525, from USGS loc. 14169, unnamed

Permian formation. 

10. cf. Spiroscala sp. (p. 137)

Side view, X 2; USNM 136526, from USGS loc. 1008, Sadlerochit(?) formation. 

11-13. Glabrocingulum (Glabrocingulum) sp. (p. 138)

Top, adapertural, and basal views, respectively, X 2; USNM 136527, from USGS loc. 14174, Siksikpuk formation. 

14-17. Nodospira ornata Yochelson and Dutro, n. sp. (p. 137)

14-16. Top, apertural, and basal views, respectively, X 1; holotype, USNM 136528, from USGS loc. 14150,

Goniatites zone, Alapah limestone.

17. Apertural view, X 1; paratype, USNM 136529, from USGS loc. 14150, Goniatites zone, Alapah limestone. 

18, 19. Portlockiella? sp. (p. 139)

Adapertural and top views, respectively, X 3; USNM 136536, from USNM loc. 3167, Lithostrotion zone, Alapah

limestone. 

20, 21. Gosseletina? sp. (p. 139)

Basal and side views, respectively, X 2; USNM 136531, from USGS loc. 13236, Lower Mississippian. 

22-24. Phymatopleura sp. (p. 139)

Adapertural, top, and basal views, respectively, X 3; USNM 136532, from USGS loc. 13234, Lower Mississippian. 

25. Neilsoniat sp. (p. 138)

Side view, X 4; USNM 136533, from USGS loc. 9184, Alapah limestone. 

26-28. New genus? A (p. 139)

Adapertural, basal and top views, respectively, X 4; USNM 136534, from USNM loc. 3110, "Zaphrentis" zone

Wachsmuth limestone. 

29. Yunnama sp. (p. 140)

Adapertural view of steinkern, X 6; USNM 136535, from USGS loc. 12785, Lower Mississippian. 

30-31. Bembexiat inumbilicata Yochelson and Dutro, n. sp. (p. 138)

Apertural and side views, respectively, X 1; Holotype: USNM 136536, from USGS loc. 10862, Goniatites zone, 

Alapah limestone.
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FIGURE 1. cf. Murchisonia sp. (p. 144)

Side view, X 4; USNM 136537, from USGS loc. 13240, Lower Mississippian.

2. Platyzona sp. (p. 144)

Side view, X 2; USNM 13658, from USGS loc. 13246, probably Upper Mississippian.

3. lanthinopsis? sp. (p. 144)

Side view, X 2; USNM 13659, from USGS loc. 12785, Lower Mississippian.

4. Scaphopod, genus indeterminate (p. 144)

Side view, X 2; USNM 136546 from USGS loc. 13246, probably Upper Mississippian.

5. Naticopsis (Naticopsis) sp. (p. 143)

Side view, X 2; USNM 136540 from USGS loc. 13235, Lower Mississippian.

6. Loxonema sp. (p. 144)

Side view, showing growth lines, X 4; USNM 136541, from USGS loc. 11828, Goniatites zone, Lisburne group. 

7-9. Anomphalus sp. (p. 142)

Adapertural, top, and basal views, respectively, X 3; USNM 136547, from USNM loc. 3167, Lithrostrotion zone,

Alapah limestone. 

10-16. Anematina rockymontanum (Shimer) (p. 141)

10. 12, 13. Two side and basal views, respectively, X 2; holotype, GSC 5093, from Lower Mississippian of Lake Minnewanka Alberta.

11. Side view, X 2; paratype, GSC 5093a, from Lower Mississippian at Lake Minnewanka, Alberta.

14. Adapertural view, X 2; USNM 136542, from USGS loc. 11808, Lower Mississippian.

15. 16. Adapertural and apertural views, respectively, X 2; USNM 136543, from USGS loc. 13288, Lithostrotion zone,

Alapah limestone. 

17-19. Platyceras (Orthonychia) sp. (p. 141)

17. Side view, X 1; USNM 136544a, from USNM loc. 3089, "Zaphrentis" zone, Wachsmuth limestone.

18. Side view, X 1; USNM 136545, from USGS loc. 9186, Lower Mississippian.

19. Side view, X 1; USNM 136544b, from loc. 3089, "Zaphrentis" zone, Wachsmuth limestone. 

20-25. Naticopsis (Naticopsis) suturicompta Yochelson and Dutro, n. sp. (p. 142)

20. 21. Enlargement showing shell layers, and adapertural view, respectively, X 4 and X 1; paratype: USNM 136548,

from USNM loc. 3088, Naticopsis zone, Alapah limestone. 

22-24. Side, apertural, and top views, respectively X 1; holotype, USNM 136549, from USGS loc. 9187, Alapah

limestone (?).

25. Adapertural view, X 1; paratype, USNM 136550 from USNM loc. 3170, Naticopsis zone, Alapah limestone. 

26, 27. New genus? B (p. 139)

Basal and side views, respectively, X 1; USNM 136551, from USGS loc. 13215, unnamed Permian formation. 

28. Platyceras (Platyceras) sp. (p. 140)

Top view showing early whorls, X 4; USNM 136552, from USGS loc. 14035, Upper Mississippian.

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