Geologic units in Brooke county, West Virginia

Monongahela Group (Pennsylvanian) at surface, covers 39 % of this area

Non-marine cyclic sequences of sandstone, siltstone, red and gray shale, limestone, and coal. Contains the Uniontown and Pittsburgh Formations. Extends from the top of the Waynesburg coal to the base of the Pittsburgh coal. Includes the Waynesburg, Uniontown, Sewickley, Redstone and Pittsburgh coals. Thickness is 170 feet in Mineral and Grant Counties.

Conemaugh Group (Pennsylvanian) at surface, covers 36 % of this area

Cyclic sequences of red and gray shale, siltstone, and sandstone, with thin limestones and coals. Mostly non-marine. May be divided into Casselman and Glenshaw Formations. Extends from the base of the Pittsburgh coal to the top of the Upper Freeport coal. Includes the Elk Lick, Bakerstown, and Mahoning coals, and the Ames and Brush Creek Limestones.

Dunkard Group (Permian/Pennsylvanian) at surface, covers 19 % of this area

Non-marine cyclic sequences of sandstone, siltstone, red and gray shale, limestone, and coal. Contains the Greene, Washington and Waynesburg Formations. Extends from the top of the exposed bed rock section to the top of the Waynesburg coal. Includes the Washington coals and limestones. Palynological evidence favors a Pennsylvanian age, at least for the lower portion.

Quaternary Alluvium (Quaternary) at surface, covers 6 % of this area

Alluvial deposits of sand, gravel, silt, and clay.

Conemaugh Group (Pennsylvanian) at surface, covers 0.4 % of this area

Shale, siltstone, and mudstone: Shale, black, gray, green and red; clayey to silty; locally contains marine fossils in lower half of unit; calcareous in part. Siltstone, gray, green and red, locally variegated; clayed to sandy; thin bedded to nonbedded. Mudstone, black, gray, green, red, and yellow, variegated in part; clayey to silty; locally calcareous; commonly nonbedded. Sandstone, green-gray weathers to shades of yellow-brown; mostly very fine to medium grained, locally conglomeratic; thin to massive to cross bedded; locally calcareous. Limestone and coal; thin and discontinuous. Limestone, black, gray and green; micritic to coarse grained; thin bedded to concretionary with marine fossils common in lower half of interval; thin to medium bedded, nonmarine limestone common in upper half of unit. Coal, thin, bituminous, impure; very locally thick enough for economic development. Lateral and vertical lithic variability and gradation common. Unit as much as 500 feet thick.

Monongahela Group (Pennsylvanian) at surface, covers 0.1 % of this area

Cyclic sequences of limestone, shale, sandstone, and coal; commercial coals present; base is at bottom of Pittsburgh coal.

Waynesburg Formation (Permian and Pennsylvanian) at surface, covers < 0.1 % of this area

Cyclic sequences of sandstone, shale, limestone, and coal; commercial coals present; base is at bottom of Waynesburg coal.

Casselman Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Cyclic sequences of shale, siltstone, sandstone, red beds, thin, impure limestone, and thin, nonpersistent coal; red beds are associated with landslides; base is at top of Ames limestone.

Washington Formation (Permian) at surface, covers < 0.1 % of this area

Cyclic sequences of sandstone, shale, limestone, and coal; includes some red shale; base is at bottom of Washington coal.

Greene Formation (Permian) at surface, covers < 0.1 % of this area

Cyclic sequences of sandstone, shale, red beds, thin limestone, and thin, impure coal; base is at top of Upper Washington limestone.

Glenshaw Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Cyclic sequences of shale, sandstone, red beds, and thin limestone and coal; includes four marine limestone or shale horizons; red beds are involved in landslides; base is at top of Upper Freeport coal.