Usage:
Tullock Member of Fort Union Formation (MT*,SD?,WY*)
Tullock Formation of Fort Union Group (MT)
Tullock Formation (ND?)
Subunits:
FORMATION STATUS (alphabetical) --all in MT: Collins Ranch Member, Nelson Ranch Member.
Geologic age:
early Tertiary (early Paleocene)*
Type section, locality, area and/or origin of name:
Named from exposures in valley of Tullock Creek, [in T. 3 N., R. 35 E., Treasure Co.], southeastern MT (Rogers and Lee, 1923).
AAPG geologic province:
Central Montana uplift*
Powder River basin*
Williston 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 ([ ]).