Graywacke and shale of Martinsburg Formation (PAOmgs;23)

State	Pennsylvania
Name	Graywacke and shale of Martinsburg Formation
Geologic age	Ordovician
Original map label	Omgs
Primary rock type	shale
Secondary rock type	graywacke
Other rock types	sandstone
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale (Bed) Minor Sedimentary > Clastic > Sandstone (Bed)includes autochthonous sandstone and shale of Shochary Ridge Sedimentary > Clastic > Sandstone > Graywacke (Bed)
Map references	Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources, 2001, Bedrock Geology of Pennsylvania, edition: 1.0, digital map. Retrieved from internet 9-30-2004; <http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx> DL Data: pageoexp.zip [http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx]
Unit references	Berg, T. M., Edmunds, W. E., Geyer, A. R., and others, compilers, 1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., Map 1, 2nd ed., 3 sheets, scale 1:250,000. Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources, 2001, Bedrock Geology of Pennsylvania, edition: 1.0, digital map. Retrieved from internet 9-30-2004; <http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx> DL Data: pageoexp.zip [http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx]