The Casselman Formation mapped

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

bedrock unit in

Pennsylvania Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Ma ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; ...

, and

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the ...

, of

Pennsylvanian Pennsylvanian may refer to: * A person or thing from Pennsylvania * Pennsylvanian (geology) The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timesca ...

age. It is the uppermost of two formations in the Conemaugh

Group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

, the lower being the Glenshaw Formation. The boundary between these two units is the top of the marine Ames Limestone. The Conemaugh Group overlies the Upper Freeport coal bed of the Allegheny Formation and underlies the

Pittsburgh coal seam The Pittsburgh Coal Seam is the thickest and most extensive coal bed in the Appalachian Basin; hence, it is the most economically important coal bed in the eastern United States. The Upper Pennsylvanian Pittsburgh coal bed of the Monongahela Group ...

of the Monongahela Group. The Conemaugh Group consists of cyclic sequences of shale, siltstone, sandstone, red beds, thin impure limestone, and thin nonpersistent coal. Red beds are associated with landslides. The thickness of the Conemaugh Group averages about 400 feet in Ohio, and it ranges from 450 feet on the Ohio River in West Virginia to 520 feet in Washington County, Pennsylvania, and then to 890 feet in Somerset County, Pennsylvania.Assessment of Appalachian Basin Oil and Gas Resources: Carboniferous Coal-bed Gas Total Petroleum System http://pubs.usgs.gov/of/2004/1272/2004-1272.pdf Citing Arkle and others, 1979; Collins; 1979; Edmunds and others, 1999 ''

Fedexia ''Fedexia'' is an extinct genus of carnivorous temnospondyl within the family Trematopidae. It lived 300 million years ago during the late Carboniferous period. It is estimated to have been long, and likely resembled a salamander.

'' remains are among the fossils that have been recovered from the formation.

Footnotes

Pennsylvanian Series Geologic formations of Pennsylvania Geologic formations of Maryland Geologic formations of West Virginia {{Maryland-geologic-formation-stub