Usage:
O'Brien Spring Sandstone Member of Haystack Mountains Formation of Mesaverde Group (WY*)
Geologic age:
Late Cretaceous (Campanian)*
Type section, locality, area and/or origin of name:
Type section: 9.6 km north of town of Sinclair, southern Haystack Mountains, in NE/4 NE/4 sec. 22, NE/4 sec. 23, and SE/4 SE/4 sec. 14, T. 22 N., R. 86 W., Carbon Co., south-central WY. Named from exposures at O'Brien Spring, in SW/4 sec. 9, T. 24 N., R. 86 W., Seminole Dam SW 7.5-min quadrangle (Gill and others, 1970).
AAPG geologic province:
Green River 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 ([ ]).