National Geologic Map Database
Geologic Unit: Orellan
Usage:
Geologic age:
Type section, locality, area and/or origin of name:
AAPG geologic province:
Usage:
Orellan age*
Geologic age:
Tertiary*
Oligocene, early
Type section, locality, area and/or origin of name:
Name based on Orella Member of Brule Formation, type locality, Orella, northwestern NE (Wood and others, 1941).
AAPG geologic province:
North America
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 ([ ]).