Usage:
Risco Formation (CA)
Geologic age:
Late Cretaceous(?)
Type section, locality, area and/or origin of name:
Comprises upper parts of both Risco Canyon and next adjacent canyon to the west, west of Orchard Peak, Annette quadrangle, Kern Co., southern CA. Formation extends as nearly continuous band of outcrop from northwest corner of Orchard Peak area southeastward, then eastward almost to Devil's Den where it ends abruptly against Hex thrust (Marsh, 1956 [abs.], 1960).
AAPG geologic province:
San Joaquin 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 ([ ]).