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National Geologic Map Database

Geologic Unit: Ledger

Usage:

Ledger Dolomite (PA*,MD*,VA*)
Ledger Formation (PA)


Subunits:

lower dolomite member, Willis Run Member, upper dolomite member (PA)


Geologic age:

Cambrian, Early
Cambrian, Middle*


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

Named from Ledger, Lancaster Co., PA (Stose and Jonas, 1922).


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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).