Usage:
El Pico Clay of Claiborne Group (TX*)
Geologic age:
early Tertiary (middle Eocene)*
Type section, locality, area and/or origin of name:
Type section (composite): exposed in many places along breaks of the Rio Grande for at least 25 mi upstream from mouth of Sombrerito Creek, Webb Co., southern TX (Eargle, 1968; see also Lonsdale and Day, 1937, USGS Water-Supply Paper 778, fig. 3, p. 35-37).
Named from El Pico, a conspicuous mesa-butte in Webb Co., about 8.5 airline mi northwest of downtown Laredo, in approx. center of shoe-shaped bend of the Rio Grande (thus, name of ranch on which it is located, La Bota, the boot), about 1 mi northwest of mouth of Sombrerito Creek [Lat. 27 deg. 37 min. 23 sec. N., Long. 99 deg. 33 min. 59 sec. W., Laredo West 7.5-min quadrangle], Webb Co., southern TX (Eargle, 1968).
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 ([ ]).