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 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 ([ ]).