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National Geologic Map Database

Geologic Unit: Blackford

Usage:

Blackford Formation (GA,TN,VA*,WV*)
Blackford Formation of Chickamauga Group (TN)


Geologic age:

latest Middle and/or earliest Late Ordovician (Chazyan)*


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

Notable exposures along U.S. Route 19 at several places between Pounding Mill Branch and Pisgah Chapel, Tazewell Co., southwestern VA and near Blackford, Russell Co., southwestern VA (Butts, 1940).


AAPG geologic province:

Appalachian basin*


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 ([ ]).