Sample Detail of
Sample: Sample No. 60AWr60
Locality: Field No. 60AWr60
Description: Mt. McKinley National Park. Lat. 63 degrees 38.4' N., long. 149 degrees 29' W. West of Sanctuary River. Collected by Emil Peel, 1960.
Location: Alaska Quadrangle: Healy C-5
Lat.: 63o38.4 ' Long.: 149o29' "
Reference
Title: Report on Referred Fossils ,  1962 (01/11)
Report by: David L. Jones
Referred by: Florence R. Weber
Age: Cretaceous (mid-Cretaceous)
Comment:The fossil from this locality consists of the left valve of an Inoceramus close to I. concentricus Sowerby.

This species is known from Albian deposits of England, California, southern Alaska, and elsewhere. Your fossil has somewhat coarser concentric ribs than is usual for this species, and thus is closer to a form from Japan known as I. concentricus costatus Nagao and Matsumoto. This subspecies occurs in rocks of Cenomanian to Turonian ages.

Thus, a mid-Cretaceous age is indicated for the Mt. McKinley fossil, but without additional specimens a more precise age is not warranted.

Occurrence(s)
No. Group Name Qty Notes
1 Bivalves left valve of an Inoceramus close to I. concentricus Sowerby has somewhat coarser concentric ribs than is usual for this species, and thus is closer to a from known from Japan as I. concentricus costatus Nagao and Matsumoto