Monongahela Group

Shale, siltstone, and mudstone; black, red, gray and green to variegated red and yellow in the southeastern areas of Ohio; clayey to sandy; nonbedded to thin bedded; locally calcareous. Sandstone, greenish-gray weathers to shades of yellow-brown, silty to locally conglomeratic; thin to massive to cross bedded; locally calcareous. Limestone, gray, micritic, clayey to silty, thin to medium bedded; generally more common in middle and lower portions of unit. Coal, banded, bituminous, thin to as much as 8 feet thick in central and northern areas, thinner to absent in southeastern Ohio. Lateral and vertical lithic variability and gradation common. Unit as much as 350 feet thick.
State Ohio
Name Monongahela Group
Geologic age Pennsylvanian
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone (Calcareous)black, red, gray and green to variegated red and yellow in the southeastern areas of Ohio; clayey to sandy; nonbedded to thin bedded; locally calcareous.
Sedimentary > Clastic > Siltstone (Calcareous)black, red, gray and green to variegated red and yellow in the southeastern areas of Ohio; clayey to sandy; nonbedded to thin bedded; locally calcareous.
Sedimentary > Clastic > Mudstone > Shale (Calcareous)black, red, gray and green to variegated red and yellow in the southeastern areas of Ohio; clayey to sandy; nonbedded to thin bedded; locally calcareous.
Minor
Sedimentary > Clastic > Sandstone (Calcareous)greenish-gray weathers to shades of yellow-brown, silty to locally conglomeratic; thin to massive to cross bedded; locally calcareous.
Sedimentary > Carbonate > Limestone (Bed)gray, micritic, clayey to silty, thin to medium bedded; generally more common in middle and lower portions of unit.
Incidental
Sedimentary > Coal > Bituminousbanded, bituminous, thin to as much as 8 feet thick in central and northern areas, thinner to absent in southeastern Ohio.
References

Slucher, E.R., (principal compiler), Swinford, E.M., Larsen, G.E., and others, with GIS production and cartography by Powers, D.M., 2006, Bedrock geologic map of Ohio: Ohio Division of Geological Survey Map BG-1, version 6.0, scale 1:500,000.

NGMDB product
Counties Athens - Belmont - Carroll - Gallia - Guernsey - Harrison - Jefferson - Lawrence - Meigs - Monroe - Morgan - Muskingum - Noble - Washington