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National Geologic Map Database

Geologic Unit: Hermosa

Usage:

Hermosa Formation (AZ*,CO*,NM*,UT*)
Hermosa Group (AZ*,CO*,NM*,UT*)


Subunits:

GROUP STATUS (alphabetical): Honaker Trail Formation (AZ*,CO*,NM*,UT*), Lime Ridge Formation (CO,UT), Paradox Formation (CO*,NM,UT), Pinkerton Trail Formation (AZ*,CO*,NM*,UT*) or Pinkerton Trail Limestone (CO,UT).
FORMATION STATUS: Paradox Member (AZ,CO,UT).


Geologic age:

Middle to Late Pennsylvanian*


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

Named from Hermosa Creek, which flows into Animas River north of Durango, [Durango quadrangle, La Plata Co.], southwestern CO (Cross and Spencer, 1900).
Type section: in secs. 26 and 35, T. 37 N., R. 9 W., La Plata Co., southwestern CO (Roth, 1934).


AAPG geologic province:

Black Mesa basin*
Paradox basin*
Plateau sedimentary province*
San Juan basin*
San Juan Mountains province*


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 ([ ]).