Martinsburg Formation

Predominantly gray to dark shale, yellowish in the upper portion. Contains scattered thin limestone and sandstone interbeds, particularly in the lower portion. The upper portion constitutes the Reedsville Shale.
State West Virginia
Name Martinsburg Formation
Geologic age Ordovician
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale (Bed)predominantly gray to dark shale, yellowish in the upper portion; The upper portion constitutes the Reedsville Shale.
Minor
Sedimentary > Clastic > Sandstone (Bed)Contains scattered thin limestone and sandstone interbeds
Sedimentary > Carbonate > Limestone (Bed)Contains scattered thin limestone and sandstone interbeds
Comments Thickness: Northeastern 300-1800 ft, Western 995 ft, Southeastern 1200 ft. Reedsville Shale in Northeastern portion (Western Pendleton County) is 1800 ft thick.
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.

NGMDB product
Counties Berkeley - Grant - Hampshire - Hardy - Jefferson - Mercer - Monroe - Pendleton