Usage:
Portuguese Tuff Bed of Altamira Shale Member of Monterey Shale (CA*)
Geologic age:
Miocene, middle*
Type section, locality, area and/or origin of name:
Type region [area] in Klondike Canyon near Portuguese Bend [San Pedro 7.5-min quadrangle, Los Angeles Co., CA] (Woodring and others, 1946).
AAPG geologic province:
Los Angeles 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 ([ ]).