Mississippian Cephalopods of Northern and Eastern Alaska GEOLOGICAL SURVEY PROFESSIONAL PAPER 283 Mississippian Cephalopods of Northern and Eastern Alaska By MACKENZIE GORDON, JR. GEOLOGICAL SURVEY PROFESSIONAL PAPER 283 Descriptions and illustrations of 4.3 nautiloids and ammonoids and correlation of the assemblages with European Carboniferous goniatite zones UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1957 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 $1.50 (paper cover) CONTENTS Page Page Abstract..__________________________________________ 1 Stratigraphic and^geographic distribution—Continued Introduction. ________________________________________ 1 Brooks Range—Continued Previous work____________________________________ 1 Kiruktagiak River basin—Chandler Lake area, 7 Composition of the cephalopod fauna_______________ 2 Siksikpuk River basin_____-----__--__-_____ 10 Stratigraphic and geographic distribution of the cepha- Anaktuvuk River basin_________------__-_ 10 lopods_________________________________________ 2 Nanushuk River basm____--_-___----------- 10 Brooks Range._________________________________ 2 Echooka River basin_--_---_-_-_-_---__-_-_ 10 Cape Lisburne region________________________ 4 Eagle-Circle district.___________________________ 10 Lower Noatak River basin_____-______..______ 4 Age and correlation of the cephalopod-bearing beds___. 13 Western De Long Mountains-________________ 4 Mississippian cephalopod-collecting localities in Alaska. 16 Eastern De Long Mountains......____________ 6 Systematic descriptions.____________-_-_-__-_-_.-_-. 19 Ipnavik River basin___._ ____________________ 7 Bibliography.____________„_______________,____--_. 57 Etivluk River basin.________________________ 7 Index ____________________________________________ 59 ILLUSTRATIONS [Plates follow page 62] PLATE 1. Orthoconic nautiloids of the genera Rayonnoceras, Page Michelinoceras, and Bactrites? 11. Munsteroceras saginatum Gordon, n. sp., front 2. Orthoconic nautiloids of the genera Kionocerasf, view in outline and suture; M. sp., suture. _ 35 Cycloceras, Adnatoceras, Dolorthoceras, Euloxo- 12. Bollandites bowsheri Gordon, n. sp., suture ceras, and Pseudorthoceras. and front view in outline. ______________ 37 3. Coiled nautiloids: Stroboceras and Knightoceras; and 13. Bollandites kiligwae Gordon, n. sp., cross sec­ ammonoids: Dimorphoceras and Eothalassoceras. tion and suture _ _____________________ 38 4. Ammonoids of the genera Ammonellipsites, Miin- 14. Bollandites cf. B. sulcatum Bisat, cross sec­ steroceras, Bollandites, and Beyrichoceras. tion and suture____________________-___ 39 5. Goniatites crenistria Phillips. 15. Beyrichoceras micronotum (Phillips), sutures 6. Ammonoids of the genera Goniatites, Neoglyphio- of two specimens and front view in out­ ceras, Sudeticeras, Girtyoceras, Pronoritesf, and line. _________________________________ 41 Entogonites. 16. Beyrichoceras sp., suture and front view in Page outline. ______________________________ 42 FIGURE 1. Index map of the northern part of Alaska. __ 3 17. Goniatites crenistria Phillips, sutures of three 2. Preliminary correlation of Mississippian rocks specimens and cross section. ____________ 43 in the western and central Brooks Range. _ 18. Goniatites cf. G. sphaericus (Sowerby), front 3. Index map of the western part of the Brooks view in outline of two specimens and Range______________________________ 45 4. Index map of the central part of the Brooks 19. Goniatites cf. G. granosus Portlock, suture _ 46 Range_______________________________ 20. Goniatites? sp., suture _____--_____-_-____. 47 5. Geologic sketch map of the Kiruktagiak- 21. Sudeticeras alaskae Gordon, n. sp., front view Chandler Lake area___________________ in outline and suture_--_-_-----________ 48 6. Generalized geologic map of part of the Eagle- 22. Girtyoceras arcticum Gordon, n. sp., cross sec­ Circle district _________________________ 11 tion and sutures of two specimens. ______ 50 7. Rayonnoceras rangifer Gordon, n. sp., dia­ 23. Girtyoceras endicottense Gordon, n. sp., grammatic vertical section.____________ 19 suture.. _ _____________________________ 51 8. Knightoceras pattoni Gordon, n. sp., cross sec­ 24. Entogonites borealis Gordon, n. sp., cross sec­ tion of mature whorl___________________ 27 tion and suture________________________ 53 9. Stroboceras crispum Gordon, n. sp., cross sec­ tion and suture___________-____________ 28 25. Eothalassoceras aurorale Gordon, n. sp., front 10. Ammonellipsites (Fascipericyclus) polaris view in outline and suture. _____________ 54 Gordon, n. sp., cross section and suture; 26. Dimorphoceras algens Gordon, n. sp., front A. (F.) aff. A. polaris, part of suture_-__- 34 view in outline and suture ______________ 55 TABLES Page Page TABLE 1. Distribution of cephalopod species in the 2. Tentative correlation of the goniatite-bearing Brooks Range and in the Eagle-Circle dis­ beds of northern and eastern Alaska. ____ 14 trict __-_________-_______-_____-.--_--- 13 HI MISSISSIPPIAN CEPHALOPODS OF NORTHERN AND EASTERN ALASKA By MACKENZIE GORDON, Jr. ABSTRACT ing these Alaskan investigations, the cephalopods are Cephalopods of Mississippian age occur in the rocks of the one of the most important because their relatively Brooks Range of northern Alaska and along the Yukon River short stratigraphic ranges make them excellent tools in the Eagle-Circle district in eastern Alaska. The cephalopod for stratigraphic correlation. faunas include goniatites that can be correlated with zones in northwest Europe, especially the British Isles. Twenty-four collections of fossil cephalopods de­ The earliest Mississippian goniatites are found in the western scribed in this paper were made during^ the course of part of the Brooks Range, where an unnamed black shale the Navy's oil exploration. A collection from near unit on Iligluruk Creek and a calcareous sandstone unit on a Cape Lisburne and one from the lower Noatak River branch of the Kiligwa River have yielded Munsteroceras prob­ valley near the west end of the Brooks Range are from ably of late Tournaisian age. Loose limestone blocks on the lower Noatak River and black shale on the Kiligwa River, both earlier reconnaissance work of the U. S. Geological tentatively referred to the lower part of the Lisburne group, Survej7, as are twelve additional collections from the contain the genus Ammonellipsites at a stage of development Eagle-Circle district of eastern Alaska. The 38 col­ that suggests very late Tournaisian or early Vise"an age. lections studied shed considerable light on the distri­ In the central Brooks range most of the cephalopods found bution of the cephalopods in a region where previously have come from the upper middle part of the Alapah limestone of the Lisburne group. These fossils can be correlated with very little was known about them. A rough correla­ three faunal units of the British Carboniferous section, the tion can now be made with the Carboniferous goniatite upper Beyrichoceras or Goniatites maximus (B2) zone, the G. zones of northwest Europe, particularly those of the crenistria (Pja) subzone, and the G. elegans (Pic) subzone, the British Isles. first of Middle Visdan and the last two of Upper Vise'an age. The writer is especially indebted to J. T. Dutro, Jr., They come, however, from within rather narrow stratigraphic limits in the Alaskan section. for stratigraphic information assembled for use in this The Goniatites granosus (Pz) zone, the uppermost of the report. Other unpublished stratigraphic data have Vis6an goniatite zones, is known only from the Eagle-Circle been supplied by A. L. Bowsher, W. P. Brosge, district where it occurs in the lower middle part of the Calico W. W. Patton, Jr., and I. L. Tailleur. J. B. Reeside, Bluff formation. Cravenoceras sp. possibly representing the Jr., and W. A. Cobban have contributed many helpful Eumorphoceras pseudobilingue (Ei) zone of early Namurian age has been found in the Calico Bluff formation at one locality in suggestions. The writer also wishes to express his the Eagle-Circle area. appreciation to members of the Geological Survey of The 19 nautiloid species described in this report have been Great Britain, particularly to T. Robertson, C. J. referred to 12 genera, as follows: Rayonnoceras, Michelinoceras, Stubblefield, F. M. Trotter, G. A. Kellaway, and Bactritesf, Cycloceras, Kionocerasf, Dolorthoceras, Adnatoceras, D. McGraw, who greatly facilitated his visit in 1952 to Euloxoceras, Pseudorthoceras, Endolobus, Knightoceras, and Stroboceras. Six new species of nautiloids are described. The Carboniferous sections in northern and western Eng­ 24 goniatite species are referred to 14 genera: Ammonellipsites, land. This made it possible for correlations of Alaskan Munsteroceras, Bollandites, Beyrichoceras, Goniatites, Sudeticeras, with British goniatite zones in this paper to be based Neoglyphioceras, Cravenoceras, Girtyoceras, Entogonites, Eothalas- largely on first-hand information. Thanks also are soceras, Dimorphoceras, Protocanitesf, and Pronoritcsf. Ten due to L. F. Spath who made cephalopod types and of the 24 species are new. specimens available for study at the British Museum INTRODUCTION (Natural History). Geologic reconnaissance and field mapping in the PREVIOUS WORK Brooks Range has greatly increased our knowledge of the late Paleozoic faunas of northern Alaska. Most