Usage:
Rich Member of Twin Creek Limestone (ID*,UT*,WY*)
Geologic age:
Jurassic, Middle*
Bajocian, late*
Type section, locality, area and/or origin of name:
Type section: on north side of Birch Creek, about 8 mi west of Woodruff, near line of secs. 18 and 19, T. 9 N., R. 6 E., Rich Co., UT (Imlay, 1967).
AAPG geologic province:
Yellowstone province*
Snake River basin*
Green River basin*
Wasatch uplift*
Uinta uplift*
Uinta 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 ([ ]).