USGS Visual Identifier
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Geologic Unit: Swift Run

Swift Run Formation (VA*,MD*,WV)

Proterozoic, Late*

Geologic Province:
Piedmont-Blue Ridge province*
Appalachian basin*

Areal Extent:

Type Locality:
Exposures on U.S. Highway 33, just east of Swift Run Gap, VA [now inaccessible]. Also exposed on Skyline Drive just north of the gap (Stose and Stose, 1944).
Reference section: good exposures of sericitic phyllite believed to be metatuff can be seen from entrance of Skyline Drive eastward from the gap. Exposures from Whitehall, Albemarle Co., into Sugar Hollow, make good substitute for type locality and are near the now-inaccessible type (Furcron, 1969).

Unit Name History:
Named (Stose and Stose, 1944).
Extended into MD (Stose and Stose, 1946).
Overview (Bloomer and Bloomer, 1955).
Revised (King, 1950).
Not used (Reed, 1955).
Contacts revised (Gooch, 1958).
Age modified; Areal limits; Overview (Brent, 1960). Revised (Nelson, 1962).
VA State Geol. Map usage (Milici and others, 1963).
Extended into WV (Cardwell, 1968).
MD State Geol. Map usage (Weaver and others, 1968).
Reference localities designated; Revised (Furcron, 1969).
Overview (Wehr, 1985).
Areal limits (Kline and others, 1991).
Revised (Rankin and others, 1993).
VA Geol. Survey usage (Rader and Evans, 1993).
Overview (Southworth, 1994).
Overview; Areal limits (Burton and others, 1995).
Revised; Areal limits (Kasselas, in press).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses ().

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013