Usage:
Atco Formation of Austin Group (TX*)
Atco Member of Austin Chalk (TX*)
Subunits:
FORMATION STATUS (alphabetical) --all in TX: Bruceville Marl Member, Vinson Chalk Member.
Geologic age:
Late Cretaceous (Coniacian to Santonian; Gulfian Provincial Epoch, Austinian Provincial Age)*
Type section, locality, area and/or origin of name:
Type locality: quarries of Universal Atlas Cement Company, town of Atco, McLennan Co., central TX (GNC index card files).
Occurs in type section of Austin Group, in vicinity of Austin, Williamson Co., central eastern TX (Murray, 1961, citing Durham, 1957, unpub. PhD dissert., Columbia Univ.).
AAPG geologic province:
Ouachita folded belt*
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 ([ ]).