Rock Specimens

Represents a Wide Range of Depositional Environments and Rock Textures

Earthy, porous calcareous tufa.

Buff-colored, coarse, detrital limestone, with cemented shell fragments.

Black, soft; most widely mined.

Gray to brown mudstone with abundant silt.

Hematite-cemented quartz; orthoquartzite.

Typical green-gray, fissile, clay-rich.

Brownish black, intermediate stage between peat and bituminous coal.

Black, fissile; commonly with carbonized fossil plant impressions.

White, mature, friable.