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National Geologic Map Database

Geologic Unit: Otter

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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).