Usage:
Big Valley Bluff Formation (CA*)
Geologic age:
Ordovician(?) to Devonian(?)*
Type section, locality, area and/or origin of name:
Type locality: exposures on Big Valley Bluff [in sec. 25, T. 16 N., R. 12 E., approx. Lat. 39 deg. 13 min. 19 sec. N., Long. 120 deg. 34 min. 35 sec. W., Duncan Peak 7.5-min quadrangle], Placer Co., CA, and on north rim of canyon of North Fork of American River west and east of Big Valley Bluff. Named from Big Valley Bluff (Harwood and others, 1995).
Reference section: along Foresthill Divide Road between Tadpole Campground and Ford Point, in secs. 5 and 6, T. 15 N., R. 13 E., [approx. Lat. 39 deg. 11 min. 08 sec. N., Long. 120 deg. 33 min. 25 sec. W., Duncan Peak 7.5-min quadrangle, Placer Co., CA] (Harwood and others, 1995).
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 ([ ]).