Usage:
Threadgill Member of Tanyard Formation of Ellenburger Group (TX*)
Threadgill Limestone (TX)
Geologic age:
Early Ordovician*
Type section, locality, area and/or origin of name:
Type section: on Threadgill and Mormon Creeks, south of Lange's Mill, northwest Gillespie Co., TX (Cloud and others, 1946).
AAPG geologic province:
Llano uplift*
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 ([ ]).