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
Typesedimentary
Sub-unitsBotetourt limestone member, St. Luke limestone member
UnderliesMartinsburg Formation
OverliesLincolnshire Formation
AreaVirginia
Thickness1200 feet[1]
Lithology
Primarylimestone, shale
Location
RegionGreat Appalachian Valley
Country United States
Type section
Named forEdinburg, Virginia
Named byCooper & Cooper, 1946

References

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  1. ^ Eugene K. Rader, 1967. Geology of Staunton, Churchville, Greenville, and Stuarts Draft quadrangles, Virginia. Virginia Division of Mineral Resources, Report of Investigations 12. Map Scale: 1:24,000.
  2. ^ Read, J. Fred; Eriksson, Kenneth A. (2012). "Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau" (PDF). Virginia Tech Scholarly Works, Department of Geosciences.
  3. ^ Cooper, Byron N.; Cooper, G. Arthur (1946). "Lower Middle Ordovician Stratigraphy of the Shenandoah Valley, Virginia". Bulletin of the Geological Society of America. 57: 35–114.