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Monongahela Formation

Monongahela Formation - Interbedded claystone, argillaceous limestone, shale, sandstone, and coal beds; Waynesburg coal at top; Pittsburg coal at base; thickness 240 feet in west, increases to 375 feet in east.
State Maryland
Name Monongahela Formation
Geologic age Pennsylvanian
Primary rock type claystone
Secondary rock type limestone
Other rock types shale; sandstone; coal
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Claystone
Sedimentary > Carbonate > Limestone
Minor
Sedimentary > Clastic > Mudstone > Shale
Incidental
Sedimentary > Clastic > Sandstone
Sedimentary > Coal
Map references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unit references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD
Counties Allegany - Garrett