The Tomstown Dolomite or Tomstown Formation is a geologic formation in Maryland, Pennsylvania, Virginia and West Virginia.Tomstown Dolomite in MarylandTomstown Dolomite in VirginiaTomstown Dolomite in West Virginia It preserves fossils dating to the Cambrian Period.
In Maryland it is described as "Interbedded light gray to yellowish-gray, thin- to thick-bedded dolomite and limestone; some shale layers; gradational contact with Antietam; thickness 200 to 1,000 feet."
In southern Maryland it is divided into four members:Brezinski, D.K, and Bell, S.C., 2009. Geologic Map and Karst Features of the Funkstown Quadrangle, Washington County, Maryland. Maryland Geological Survey, Quadrangle Geologic Map FUNKSGEO2009.1. Map Scale: 1:24,000 Dargan Member Interbedded and cyclical dolomite and limestone. Benevola Member Light gray to white, massive to poorly bedded, highly fractured sugary dolomite. Fort Duncan Member Medium- to dark-gray, thick bedded, mottled dolomite with white, void-filling sparry dolomite. Bolivar Heights Member Three lithologies from the basal layer of a tan, vuggy dolomite, to a light gray dolomitic marble called the Keedysville bed, to thin- to medium bedded layers of lime mudstone containing burrows.
See also
List of fossiliferous stratigraphic units in Maryland List of fossiliferous stratigraphic units in Pennsylvania List of fossiliferous stratigraphic units in Virginia List of fossiliferous stratigraphic units in West Virginia
References