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National Geologic Map Database

Geologic Unit: Brule

Usage:

Brule Formation of White River Group (CO*,MT*,NE*,ND*,SD*,WY*)
Brule Clay of White River Group (CO*,NE*,SD*,WY*)


Subunits:

(alphabetical): Orella Member (NE*,WY). Poleslide Member (SD), Scenic Member (SD), Whitney Member (CO,NE*,SD,WY).


Geologic age:

early Tertiary (Oligocene)*


Type section, locality, area and/or origin of name:

[Mr. Darton stated (personal commun. April 8, 1931) that he named this formation for the Brule Indians, who once roamed over Pine Ridge Indian Reservation in southern South Dakota, where the formation covers large areas, and that it is not present in Brule Indian Reservation, which occurs farther north in South Dakota (US geologic names lexicon, USGS Bull. 896; see Darton, 1899).]


AAPG geologic province:

Chadron arch*
Denver basin*
Sioux uplift*
Williston basin*
Wind River 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 ([ ]).