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National Geologic Map Database

Geologic Unit: Loudoun

Usage:

Loudoun Formation of Chilhowee Group (MD*,PA*, VA*,WV*)
Loudoun Formation (MD)


Geologic age:

Early Cambrian*


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

Named for fact all of its varieties are well developed in Loudoun Co., northern VA (Keith, 1894).


AAPG geologic province:

Piedmont-Blue Ridge province*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 ([ ]).