Usage:
Opeche Shale (CO*,MT*,NE*,ND*,SD*,WY*)
Opeche Shale Member of Goose Egg Formation (MT*,WY*)
Geologic age:
early Permian (late Kungurian)*
Type section, locality, area and/or origin of name:
Typically developed on Battle Creek, the Indian name of which is Opeche, [Custer Co.], western SD (Darton, 1901).
AAPG geologic province:
Chadron arch*
Denver basin*
Green River basin*
Powder River basin*
Williston basin*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).