U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database

Geologic Unit: Old Mill Branch

Usage:

Old Mill Branch Metasiltstone Member of Popes Head Formation (VA*)


Geologic age:

Cambrian*
Ordovician


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

Exposures along Old Mill Branch between Clifton Road and the Occoquan Reservoir, Manassas 7.5-min quadrangle, Fairfax Co., VA (Drake and Lyttle, 1981).


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 ([ ]).