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National Geologic Map Database

Geologic Unit: Fredericksburg

Usage:

Fredericksburg Group (AR*,NM,OK,TX*, and LA*-subsurface)
Washita Group and Fredericksburg Group, undifferentiated (MS-subsurface)


Subunits:

(alphabetical): Comanche Peak Limestone (TX*) or Comanche Peak Formation (NM), Edwards Limestone (TX*), Gatesville Formation (TX), Goodland Formation (LA,OK,TX) or Goodland Limestone (LA*,OK*,TX*), Kiamichi Formation (LA*,NM,OK*,TX*), Paluxy Formation (LA), Pryor Formation (TX), Telephone Canyon Formation (TX), University Mesa Marl (TX), Walnut Clay (AR*,LA*,OK*,TX*) or Walnut Formation (NM,TX*) or Walnut Marl (OK,TX).


Geologic age:

Early Cretaceous (Comanchean Provincial Epoch)*


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

Named from Fredericksburg, Gillespie Co., TX (Hill, 1887).


AAPG geologic province:

Permian basin*
Strawn basin*
Ouachita folded belt*
Bend arch*
Llano uplift*
Fort Worth syncline*
South Oklahoma folded belt*
Arkla basin*
Gulf Coast basin*
East Texas basin*
Kerr 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 ([ ]).