Name: Oil Shale (Kerogen Shale)

Geologic Name:  Green River Formation

Reference:  Bradley, W.H., Origin and microfossils of the oil shale of the Green
River formation of Colorado and Utah: U.S. Geol. Survey Prof. Paper 168, 1931.

Microscopic characters:  A brown carbonaceous substance obscures the identity
of most of the mineral content of the rock.  Minute grains of feldspar, quartz,
sericite and magnetite are discernible.