Usage:
Llaves Member of San Jose Formation (CO*?,NM*)
Geologic age:
Tertiary*
Eocene, early*
Type section, locality, area and/or origin of name:
Type section (composite): upper part in SW/4 sec. 4, T. 25 N., R. 1 W.; and lower part in N/2 sec. 18, T. 25 N., R. 1 E., Rio Arriba Co., NM. Named from exposures near mouth of Canoncito de Las Yeguas, about 1.25 mi northwest of Llaves Post Office, Rio Arriba Co., NM (Baltz, 1967).
AAPG geologic province:
San Juan 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 ([ ]).