Usage:
Hannold Hill Formation of Tornillo Group (TX)
Hannold Hill Member of Tornillo Formation of Chilicotal Group (TX)
Subunits:
Exhibit Sandstone Bed (TX) or Exhibit Sandstone Member (TX).
Geologic age:
Eocene
Type section, locality, area and/or origin of name:
Type section: about 0.75 mi northeast of the abandoned rock crusher site on southern Tornillo Flat, Brewster Co., Big Bend National Park, Brewster Co., southwestern TX. Named from Hannold Hill on the Big Bend Park Road in south-central Tornillo Flat (Maxwell and Hazzard, 1967).
AAPG geologic province:
Permian 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 ([ ]).