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National Geologic Map Database

Geologic Unit: Clear Fork

Usage:

Clear Fork Group (TX*)
[?] Clear Fork Formation (TX)


Subunits:

GROUP STATUS (alphabetical) --all in TX: Arroyo Formation*,Bullwagon Dolomite, Choza Formation*, Dean Sandstone, Kirby Lake Dolomite or Kirby Lake Limestone, /Lytle Limestone, Merkel Dolomite, Rainy Limestone, Standpipe Limestone, Vale Formation*.
[?] FORMATION STATUS (alphabetical) --all in TX: /Lytle Limestone Member, Rainy Limestone Member, Standpipe Limestone Member.


Geologic age:

Early Permian (Cisuralian; Leonardian)*


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

Probably named from Clear Fork of Brazos River, Jones and Shackelford Cos., central northern TX (US geologic names lexicons, USGS Bull. 896, 1200).


AAPG geologic province:

Bend arch
Palo Duro basin
Permian basin


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 ([ ]).