Usage:
Bass Limestone of Unkar Group of Grand Canyon Supergroup (AZ*)
Bass Formation of Unkar Group of Grand Canyon Supergroup (AZ)
Subunits:
Hotauta Conglomerate Member (AZ).
Geologic age:
Mesoproterozoic*
Type section, locality, area and/or origin of name:
Named from Bass Canyon, south side of Colorado River, Grand Canyon, Shinumo quadrangle, Coconino Co., northern AZ, where typically exposed (Noble, 1914).
AAPG geologic province:
Southern Rocky Mountain region*
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 ([ ]).