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Helderberg Group

Helderberg Group - mostly cherty limestone, with some sandstone and shale. Contains several named stratigraphic units, including the Keyser Formation, which is partly Silurian and includes the Clifton Forge Sandstone and Big Mountain Shale Members.
State West Virginia
Name Helderberg Group
Geologic age Devonian
Comments Includes: Rocky Gap Sandstone (USGS) used on Southeastern columnar section. Thickness: Northeastern 350-445 ft, Western 210 ft, Southeastern 0-50 ft, Southeastern - Rocky Gap Sandstone 175 ft.
Primary rock type limestone
Secondary rock type sandstone
Other rock types shale
Lithologic constituents
Sedimentary > Carbonate > Limestonemostly cherty limestone
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Mudstone > Shale
Map references
Digital version of 1968 printed map available from with the specific data available from
Unit references
Cardwell, D.H., Erwin, R.B., and Woodward, H.P., 1968 (slightly revised 1986), Geologic Map of West Virginia: West Virginia Geological and Economic Survey, Map 1, East Sheet, scale 1:250,000.
Counties Grant - Greenbrier - Hampshire - Hardy - Mineral - Pendleton - Pocahontas