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Reference
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| Title: |
Mississippian Cephalopods of North and Eastern Alaska
,
1957
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| Report by: |
Mackenzie Gordon
, Jr.
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| | Age: | Visean (late middle to early late Visean) |
| Formation: | Alapah Limestone |
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| Comment: | On Tiglukpuk Creek, in the southern part of the Siksikpuk River basin, a collection was made by Reiser from the black chert and shale member of the Alapah limetone, 525 feet below the top of the formation in measured section B-19. The following cephalopods are identified (USGS loc. 11804): Euloxoceras sp.
Sudeticeras alaskae Gordon, n. sp.
Eothalassoceras aurorale Gordon, n. sp. This collection is of special interest because it combines the first records of the genera Euloxoceras and Eothalassoceras in rocks earlier than Pennsylvanian age with the first record of Sudeticeras in the western hemispher. Euloxoceras occurs in rocks of Mississippian age elsewhere but this has not yet been recorded in the literature. Sudeticeras is not known above the Goniatites granosus (Psubscript2) zone. At this locality the total thickness of the Alapah limestone is approximately 1,870 feet, according to Brosge and Reiser (1951, written communication), the black chert and shale member is 185 feet thick, and the fossil collection came from a horizon 60 feet above the base of the member and a few feet above a phosphatic shale zone. (from p. 10) [Note by R.B. Blodgett: Table 2 on p. 14 indicates this locality to be part of "Beds with Goniatites crenistria and Beyrichoceras micronotum", exposed in the central Brooks Range, and which is shown as being of late middle to early late Visean age] |
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