From Ohio History Central
The Bedford Shale was named for exposures near Bedford, in Cuyahoga County, where it is about 95 feet thick. The unit is primarily gray in color but has a red phase that is evident in central Ohio. The Bedford Shale is well exposed in northern, central, and southern Ohio and has been used as a source of clay for making bricks and other ceramic products. Traditionally, the Bedford has been considered to be Mississippian in age but recently the unit, along with the overlying Berea Sandstone, has been assigned a Late Devonian age. The Bedford Shale represents sediment washed into the Ohio sea from uplands to the north in Canada and from the Catskill delta to the east.