"Specimens"

Glassy; most specimens float in water.

Gray to brown mudstone with abundant silt.

Lustrous, black 'hard coal'.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Fightly cemented, medium-to-coarse quartz grains.

Brownish black, intermediate stage between peat and bituminous coal.

Hematite-cemented quartz; orthoquartzite.

Pale pink felsite, with small sanidine phenocrysts.

Dense and massive.

Light gray, fine small clasts.

Gray to white, coarse crystalline, carbonate rock.

Typical green-gray, fissile, clay-rich.

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

Silvery, paragranite and muscovite-rich with medium garnet crystals.

Chlorite-mica with perfect slaty cleavage.

Dark gray with abundant gas pocket vesicles.