Brush Creek chert

Brush Creek chert comes from the Brush Creek limestone member of the Pennsylvanian-age Conemaugh Group, which crops out across central and southeastern Ohio and into northern West Virginia, western Pennsylvania and eastern Kentucky. In Ohio the limestone runs in a thin belt from Columbiana and Jefferson counties to Lawrence and Gallia counties, and its chert facies occurs in Muskingum, Morgan, Perry, Athens, Meigs, Vinton, Gallia and Lawrence counties. The member varies a great deal: dark shales, dark gray limestone, black flint and gray shaly flint all occur. The chert is usually gray, with buff, olive-brown and light green varieties common, and it breaks with imperfect conchoidal fracture, probably because of inclusions and high carbonate content. Archaeologists in the upper Ohio Valley list it among recorded regional lithic sources.

Brush Creek limestone member of the Conemaugh Group, Pennsylvanian. In central Ohio two beds of fossiliferous limestone or chert are separated by 10-30 feet of shale; in southern Ohio the member is chert or dark gray fossiliferous limestone, thickening south from about 5 feet to 22 feet or more (Stout 1927; Stout and Schoenlaub 1945, as summarized in the PennDOT synthesis).