"Specimens"

Gray to brown mudstone with abundant silt.

Brownish black, intermediate stage between peat and bituminous coal.

Hematite-cemented quartz; orthoquartzite.

Dense and massive.

Light gray, fine small clasts.

Red-brown to gray, coarse-grained, containing feldspar and mica.

Typical green-gray, fissile, clay-rich.

Black, soft; most widely mined.

Gray to buff, with numerous ooliths and fossil fragments.

Small, rounded pebbles and tightly cemented granules.

Gray with line crinoid columnal fragments.

Gray, fine to medium-grained “Berea grit”.

Brownish gray, kerogen-rich; commercial oil source.

Well-cemented, medium-grained orthoquartzite.

Earthy, porous calcareous tufa.

Buff, coarse, crystalline “Austin Marble” with shell casts and molds.