Usage:
Keyhole Sandstone Member of Fall River Formation (SD*,WY*)
Geologic age:
late Early Cretaceous (Albian)*
Type section, locality, area and/or origin of name:
Type section: in NE/4 SE/4 sec. 21, T. 51 N., R. 66 W., Crook, Co., WY, about 0.25 mi north of Keyhole Dam on Belle Fourche River, Carlile quadrangle. Traced throughout large part of northern Black Hills (Davis and Izett, 1958).
AAPG geologic province:
Powder River 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 ([ ]).