Usage:
Twin Creek Limestone (ID,UT*,WY)
Twin Creek Formation (ID*,UT*,WY*)
Subunits:
(alphabetical): Boundary Ridge Member (ID*,UT*,WY*), Giraffe Creek Member (ID*,UT*,WY*), Gypsum Spring Member (ID*,UT*,WY*), Leeds Creek Limestone Member (UT*) or Leeds Creek Member (ID*,UT*,WY*), Rich Member (ID*,UT*,WY*), Sliderock Member (ID*,UT*,WY*), Watton Canyon Member (ID*,WY*).
Geologic age:
Jurassic, Middle*
Bajocian*
Bathonian*
Callovian*
Type section, locality, area and/or origin of name:
Not designated. Named from exposures along Twin Creek, in secs. 1, 12, and 18, T. 21 N., R. 120 W., Lincoln Co., WY (Veatch, 1907).
AAPG geologic province:
Uinta uplift*
Uinta basin*
Yellowstone province*
Snake River basin*
Green River basin*
Great Basin province*
Wasatch uplift*
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 ([ ]).