Mahantango Formation (MD*,PA*,VA,WV*)
Mahantango Formation of Hamilton Group (PA*)
(alphabetical): Backbone Ridge Siltstone Member (PA), Chaneysville Siltstone Member (MD,PA,WV), Clearfield coral bed (PA; informal term not included in this lexicon -see 1960 State Geol. Map), Clearville Member (PA) or Clearville Siltstone Member (MD,PA,WV), Dalmatia Member (PA), Donation Siltstone Member (PA), Fisher Ridge Member (PA), Fort Hunter Sandstone Member (PA), Gander Run Shale Member (PA), Knobsville Beds (PA), Landes Limestone Member (PA), Nis Hollow Siltstone Member (PA*), Pokejoy Member (WV*,MD*,PA), Sherman Ridge Member (PA), Tully Member (PA*), Turkey Ridge Sandstone Member (PA).
late Middle Devonian (Givetian)*
Exposures in valley, North Branch of Mahantango Creek, Snyder Co., central PA (Willard, 1935).
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 ([ ]).