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National Geologic Map Database

Geologic Unit: Wissahickon

Usage:

Wissahickon Formation of Glenarm Group (DE*,DC*,MD*,NJ*,PA*,VA*)
Wissahickon Formation (DE)
Wissahickon Schist of Glenarm Group (MD)
Wissahickon Group (VA)


Subunits:

Marburg Schist Member of Wissahickon Formation (PA).


Geologic age:

Late Proterozoic to Ordovician*


Type section, locality, area and/or origin of name:

Not designated. Named from Wissahickon Creek, in Philadelphia, PA.


AAPG geologic province:

Piedmont-Blue Ridge province*


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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).