Usage:
Rockyford Ash Member of Sharps Formation of Arikaree Group (SD)
Geologic age:
Tertiary
Miocene
Type section, locality, area and/or origin of name:
Type section: south end of Sheep Mountain Table, in SE/4 NE/4 NE/4 sec. 32, T. 43 N., R. 44 W., Shannon Co., SD (Harksen and others, 1961).
AAPG geologic province:
Sioux uplift
Chadron arch
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 ([ ]).