Usage:
Ishi Tuff Member of Tuscan Formation (CA*)
Geologic age:
Pliocene*
Type section, locality, area and/or origin of name:
Type locality: exposures on the north rim of Big Chico Creek canyon, about 400 m northeast of Horseshoe Lake in Bidwell Park, city of Chico, in T. 22 N., R. 2 E., Richardson Springs 15-min quadrangle, Butte Co., CA. Named from Ishi Caves on the south wall of Deer Creek canyon, in sec. 11, T. 25 N., R. 1 E., Panther Spring 15-min quadrangle, CA (Harwood and others, 1981).
AAPG geologic province:
Sacramento 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 ([ ]).