Usage:
Shannon Sandstone Member of Steele Shale (MT*,WY*)
Shannon Sandstone Member of Gammon Shale (MT*,SD*-notably in Williston basin)
Shannon Sandstone Member of Cody Shale (MT,WY*)
Shannon Member of Eagle Sandstone (MT)
Shannon Sandstone Bed of Gammon Member of Pierre Shale (WY*)
Shannon Sandstone Bed of Steele Member of Cody Shale (WY*)
Geologic age:
Late Cretaceous (Campanian)*
Type section, locality, area and/or origin of name:
Not designated. Named from town of Shannon, near Shannon oil field, in sec. 2, T. 40 N., R. 79 W., Natrona Co., central WY (Wegemann, 1911).
AAPG geologic province:
Powder River basin*
Wind River basin*
Williston 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 ([ ]).