Usage:
Otter Formation of Big Snowy Group (MT*,ND*)
Originally called Otter Creek.
Geologic age:
Late Mississippian (Chesterian)*
Type section, locality, area and/or origin of name:
Notable exposures south of town of Belt, along Little Otter and Belt Creeks, [eastern Cascade and western Judith Basin Cos.], Little Belt Mountains, central northern MT (see Weed, 1892, 1899).
AAPG geologic province:
Central Montana uplift*
Montana folded belt*
Sweetgrass arch*
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 ([ ]).