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National Geologic Map Database

Geologic Unit: Ranchester

Usage:

Ranchester Limestone Member of Amsden Formation (WY*)
Ranchester Dolomite Member of Amsden Formation (WY*)


Geologic age:

Mississippian, Late*
Chesterian, late*
Pennsylvanian, Early*
Morrowan*
Pennsylvanian, Middle*
Atokan*


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

Type section: in SE/4 sec. 33, T. 57 N., R. 87 W., Sheridan Co., WY (Mallory, 1967).
Reference section: in lower Tensleep Canyon (sta 190), in T. 47 N., R. 88 W., Washakie Co., WY (Mallory, 1967).
Reference section: in SW/4 sec. 34, T. 57 N., R. 87 W., Sheridan Co., WY (Sando and others, 1975).


AAPG geologic province:

Bighorn basin*
Green River basin*
Montana folded belt*
Powder River 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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).