Usage:
Keefer Sandstone (KY*,MD*,OH*,PA*,VA*,WV*)
Keefer Sandstone of Clinton Group (MD,PA,WV)
Keefer Formation (PA,VA,WV)
Keefer Sandstone Member of Clinton Formation (PA*,VA)
Keefer Member of Mifflintown Formation (PA)
Keefer Sandstone Member of Mifflintown Limestone (PA*)
Geologic age:
Silurian (Llandovery to Ludlow)*
Type section, locality, area and/or origin of name:
Named from Keefer Mountain, [Cherry Run and Big Cove Tannery 7.5-min quadrangles, Franklin Co., southern PA], a few mi northeast of Hancock, MD (Ulrich, 1911; Stose, 1912; US geologic names lexicon, USGS Bull. 1200).
AAPG geologic province:
Appalachian 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 ([ ]).