Usage:
Heath Formation of Big Snowy Group (MT*,ND*)
Heath Shale of Big Snowy Group (MT*)
Subunits:
(alphabetical) --all in MT: Bear Gulch Limestone Member, Tyler Sandstone Member.
Geologic age:
Late Mississippian (Chesterian)*
Type section, locality, area and/or origin of name:
Type section: north flank of Big Snowy Mountains, in sec. 6, T. 12 N., R. 20 E., Fergus Co., MT (Scott, 1935).
AAPG geologic province:
Central Montana uplift*
Powder River basin*
Williston basin*
Montana folded belt*
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 ([ ]).