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National Geologic Map Database

Geologic Unit: Butler

Usage:

Butler Clay Member of Calvert Bluff Formation of Wilcox Group (TX)
Butler Clay Member of Rockdale Formation of Wilcox Group (TX)


Geologic age:

early Tertiary (Eocene)


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

Notable exposures in central and southern TX between Brazos and Frio Rivers. Typically exposed at town of Butler, [Elgin East 7.5-min quadrangle, Bastrop Co., central TX] (Plummer, 1933).


AAPG geologic province:

Gulf Coast 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 ([ ]).