Usage:
Calhoun Shale of Shawnee Group (IA*,KS*,MO*,NE*)
Subunits:
Iowa Point Shale Member (MO).
Geologic age:
Late Pennsylvanian (Virgilian)*
Type section, locality, area and/or origin of name:
Named from exposures in Calhoun Bluffs, about 3 mi northeast of Topeka, Shawnee Co., eastern KS (Beede, 1898).
AAPG geologic province:
Forest City basin*
Nemaha anticline*
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 ([ ]).