Usage:
New Chicago Member of Logtown Ridge Formation (CA*)
Geologic age:
Jurassic, Middle*
Jurassic, Late(?)*
Type section, locality, area and/or origin of name:
Exposures in and near roadcut of Highway 49, in sec. 36, T. 7 N., R. 10 E., Amador Co., CA. Named from town of New Chicago (Duffield and Sharp, 1975).
AAPG geologic province:
Sierra Nevada province*
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 ([ ]).