Eutrephoceras nebrascensis (Meek and Hayden, 1862)

Remarks

• Collector:    Unknown (cf.com collection)

• Formation:  Montana Group, Pierre Shale

• Location:     South Dakota

General Info

Synonyms (older names and misidentifications in the literature)

• 1816 Nautilus elegans Sowerby
• 1862 Nautilus elegans var. nebrascensis Meek and Hayden
• 1864 Nautilus elegans var. nebrascensis Meek
• 1876 Nautilus elegans var. nebrascensis Meek
• 1997 Nautilus "elegans" var. nebrascensis Meek and Hayden; Larson et al.

Stratigraphic Occurrence

• Montana Group, Pierre Shale, Unnamed Shale Member of South Dakota and Wyoming

Age

• Eutrephoceras nebrascensis Meek occurs from about the Didymoceras cheyennense (Meek and Hayden) zone to the Baculites eliasi Cobban zone, middle Upper Campanian to Basal Maastrichtian in the Western Interior of the United States (~74-71 mya).

Geographic Occurrence (not an all-inclusive list)

• Montana (county ?)
• Niobrara County, WY
• South Dakota (county ?)

Remarks

         For identification and descriptions, see:

• Meek, F. B.  1876.  "A Report of the Invertebrate Cretaceous and Tertiary Fossils of the Upper Missouri Country".  In:  Hayden, F. V.  Report of the United States Geological Survey of the Territories.  Washington:  Government Printing Office.
• Meek's placement of Eutrephoceras elegans var. nebrascensis in the Benton Group (Cenomanian-Turonian strata) was incorrect.