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 strati- graphic 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 Page Abstract-._ _-______---_-_-_________________-___-___ 111 Systematic paleontology----------------------------- 131 Introduction-_------------_-________________.___.__ Ill Superfamily Bellerophontacea____________________ 13] Stratigraphic distribution of the gastropods.___________ 113 Superfamily Euomphalacea_ _____________________ 133 Superf amily Pleurotomariacea_ ___________________ 135 Rock units-_______-__________________________-_ 113 Superfamily Platyceratacea______________________ 140 Faunal zones_-------_---_--___-_______________- 115 Superfamily Microdomatacea_____---__----_-_--__ 141 Stratigraphic distribution___-__-_______-___._____ 115 Superfamily Anomphalacea.______________________ 142 Lower Mississippian undifferentiated. 115 Superfamily Neritacea-_____-_-------------__--_- 142 Upper Mississippian._______________ 118 Superfamily Murchisoniacea______________________ 144 Permian,_________________________ 118 Superfamily Loxonematacea._____--_------------- 144 Ecological and paleogeographical data_ _ ______ 119 Superfamily Subulitacea.________________________ 144 General considerations._____________________ 121 Class Scaphopoda_______________________________ 144 References cited____-___________-__-_____-_-----____ 145 Register of localities-_______________________ 122 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 adja­ cent 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 describing a poorly preserved Permian gastropod rocks of both Mississippian and Permian age; most of the fauna from Mexico, remarked: "* * * a collection of fossils studied came from the Mississippian. Although the gastropods are of use for dating the rocks only in the broadest fossils from beds in a region previously unstudied may terms, locally they are useful in establishing informal faunal tell us much, even though the specimens themselves zonation. On the basis of predominant occurrence of certain are too poorly preserved to warrant detailed descrip­ gastropods, it is possible to distinguish rocks of Early Mis­ tions or naming of species/' Most of the fossil gas­ sissippian, Late Mississippian, and Permian age. Two divi­ tropods from northern Alaska are poorly preserved; sions, based on the distribution of gastropods, are distinguished in the Upper Mississippian. One collection, consisting entirely nevertheless, their study contributes to our under­ of specimens of Glabrocingidum and Trepospira, may indicate standing of the classification and geographic distri­ the presence of rocks of Pennsylvanian age. Occurrence and bution of Paleozoic gastropods. In addition, it pre­ distribution data are summarized in tabular form. sents detailed information useful in regional strati- The gastropod faunule is composed primarily of euomphala- graphic studies. ceans, platycerataceans, pleurotomariaceans, neritaceans, and bellerophontaceans, in that order of abimdance. There is no Mississippian gastropods were first collected from indication that a distinct boreal fauna is represented. Many the Brooks Range by Philip S. Smith in 1911 (Smith, of the specimens are poorly preserved, though some well-pre­ 1913). George H. Girty listed gastropods from north­ served shells occur, particularly among the pleurotomariaceans. ern Alaska in several U.S. Geological Survey Bulle­ Thirty-four species are recognized in the systematic treat­ tins, but did not describe any of the species. Most ment ; nine of these are formally named as new species and one is referred to a previously described species. One new of his identifications are summarized in a single chart pleurotoniariacean genus, Nodospira, is described. At least (Smith and Mertie, 1930, facing p. 182). Specimens two other new genera may occur in the faunule but specimens identified by Girty were reexamined during the pres­ are too incomplete for adequate taxonomic description. The ent investigation. A few dozen specimens were col­ occurrence of two scaphopod specimens is reported. lected by A. G. Maddren, J. M. Jessup, and G. L. Most of the fossils were collected from the Brooks Range during field work in connection with geologic investigations of Harrington during the geologic reconnaissance of the Naval Petroleum Reserve No. 4 and adjacent areas. Some Alaska-Canada boundary (Maddren, 1912, p. 297- earlier collections from northern Alaska were restudied. 314). Finally, several gastropods were obtained by E. de K. Leffingwell (1919) from the Canning Fiver INTRODUCTION district. This study deals primarily with specimens collected The paleontologic literature of Alaska is well in­ from 1944 to 1953 during the geologic exploration of dexed. Dutro (1956) compiled an annotated bibliog­ Naval Petroleum Reserve No. 4. This is one of a raphy of Alaskan Paleozoic paleontology; in addition, Alaska is included in the excellent "Arctic Bibliog­ series of papers by members of the U.S. Geological raphy11 (U.S. Department of Defense, 1953-57). Survey planned to describe the various groups of Pale­ Neither of these sources records late Paleozoic gastro­ ozoic fossils collected in northern Alaska. Mackenzie pods from Alaska. About half a dozen papers illus­ Gordon, Jr. (1957) has completed a study of the Mis­ trate a few specimens from other parts of the Arctic, sissippian cephalopods. Work on certain other fos­ but all figures examined are small-size reproductions sil groups is in progress. of poorly preserved specimens. These few specimens The philosophy that has guided this work was ex­ are either unnamed or are compared with species de­ pressed by J. Brookes Knight (1953, p. 84) who, in scribed from western Europe. Ill to 140° O 168 164 160° 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 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 fos­ STRATIGRAPHIC DISTRIBUTION OF THE GASTROPODS sils described through 194:1 (Branson, 194:8) aids a The assemblage of gastropod genera dates the rocks search of the literature for previously named species. as late Paleozoic, but the gastropods themselves are Mississippian fossils, on the other hand, have not been of little value in correlating individual stratigraphic systematically indexed for many years. To the best units with rock sequences in regions outside Alaska. of the writers' knowledge, the last major papers deal­ With the exception of PortlocMetta sp., Rkineo- ing with gastropods of Mississippian age or early derma'l sp., and Twho-nellinal lata, n. sp., no g?,nera Carboniferous, are those of Koninck (1881, 1883). or species thought to be limited to rocks of Mississip­ Literature describing American Mississippian gastro­ pian age are known. No species or genera diagnostic pods is scant. of Permian age were identified. The Brooks Eange physiographic province includes On the other hand, fieldwork has demonstrated that several distinct groups of mountains extending from some of the gastropods are useful, locally, in provid­ near the 165th meridian eastward to the Canadian ing supplementary evidence that helps determine the boundary. For most of its length the range lies es­ position of certain