Edinburg Formation

The Edinburg Formation is an Ordovician-age geological formation in Virginia. It is primarily composed of basinal (deep sea) limestone and shale, and is one of the younger units in the "Middle Ordovician" sequence of the Shenandoah Valley. However, fossils have shown that it actually was deposited in the early part of the Late Ordovician. There are two major facies encompassed by the Edinburg Formation. The more abundant Liberty Hall facies consist of evenly bedded black limestone and shale. In a few areas, the Liberty Hall facies intertongue with the Lantz Mill facies. The Lantz Mill facies are grainy or cobbly wackestone which weathers to a buff brown color. Fossils are diverse, including graptolites, brachiopods, and trilobites.^[2][3]

Edinburg Formation
Stratigraphic range: Late Ordovician
Outcrop along tracks of the C&O Railway near Staunton
Type	sedimentary
Sub-units	Botetourt limestone member, St. Luke limestone member
Underlies	Martinsburg Formation
Overlies	Lincolnshire Formation
Area	Virginia
Thickness	1200 feet[1]
Lithology
Primary	limestone, shale
Location
Region	Great Appalachian Valley
Country	United States
Type section
Named for	Edinburg, Virginia
Named by	Cooper & Cooper, 1946