Green River Formation
The Green River Formation layer is one of the known rock layers that contains the largest reserve and the richest forms of oil-shale in the world; both clay and carbon enriched. The Green River Formation is a lake sediment that is composed of various layers: sandstones, oil-shales, siltstone s and mudstone (Brenes, Fleming, Rao, & Smith, 1998). The main contributor behind this rich oil-shale deposit is blue-green algae that was there during the Eocene epoch. During the Eocene, much of the Colorado Plateau was still covered by a small sea.