Usage:
Bootlegger Member of Blackleaf Formation of Colorado Group (MT*)
Geologic age:
late Early Cretaceous (Albian)*
Type section, locality, area and/or origin of name:
Type section (composite): begins near place where Bootlegger Trail crosses outcrop of member at northeast corner sec. 1, T. 21 N., R. 3 E., [Great Falls 15-min quadrangle], Cascade Co., northwestern MT, and extends westward for about 15 mi toward Muddy Creek along upper part of a south-facing escarpment to sec. 13, T. 22 N., R. 1 W., [Teton Co., Vaughn 15-min quadrangle, northwestern MT]. Named from Bootlegger Trail, a secondary road extending from Great Falls north toward Canada (Cobban and others, 1959).
AAPG geologic province:
Sweetgrass arch*
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 ([ ]).