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National Geologic Map Database

Geologic Unit: Charles

Usage:

Charles Formation of Madison Group (subsurface of MT*,ND*,SD*)
Charles facies (informal) in Madison Group (ND-subsurface)

For informal usage, the rank or lithologic term should not be capitalized.


Geologic age:

Middle Mississippian (Visean; late Osagean to Meramecian)*


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

Type section (subsurface): depth-interval 3,200 to 3,800 feet, Arro Oil and Refining Company and California Company Charles No. 4 well, in sec. 21, T. 15 N., R. 30 E., Garfield Co., MT. Named from Charles lease (Seager, 1942; Perry and Sloss, 1943; Andrichuk, 1955).


AAPG geologic province:

Montana folded belt
Bighorn basin
Sweetgrass arch
Central Montana uplift
Powder River basin
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 ([ ]).