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• 2.04.6 of 200 ft. Where the conglomeratic facies is lacking or obscured by aurficial deposits, the Ohio Creek Formation is mapped within the Mesaverde Formation (Hail, 1972). The Eocene Wasatch Formation consists of variegated mudstone and ailtstone with interbedded medium gray lenticular sandstone, which is locally conglomeratic (lunge, 1978). Maximum thickness is reported to be approximately 1600 ft. (Hail, 1972), although exposures are largely obscured by aurficial deposits. The Wasatch Formation represents terrestrial sedimentation, dominated by fluvial processes, which preceded the Lacustrine Green River Formation. Structural Geology: The Piceance Creek Basin is a typical intermontane basin of the Rocky Mountain region in which coal bearing strata are present. Bounded on the north by the Uintah Uplift, and west by the Douglas Creek Arch, the basin is asymmetric with the synclinal axis trending with the Grand Hogback. The main synclinal axis • bifurcated southwest of Meeker, Colorado, and trends northwest. The Douglas Creek Arch, south of Rangely, Colorado, is characterized by extensive faulting and numerous subsidiary structural flexures present throughout the basin (Johnson, 1982). Abundant tertiary intrusive bodies, located in the southeastern portion, give the basin a northwesterly plunge. In the southwestern portion, 3 to 5 degree dips prevail while along the Grand Hogback, vertical to overturned beds are not uncommon. Although the Piceance Creek Basin was formed during the Larimide Orogeny, recent seismic activity detected near Carbondale, Colorado, may suggest the diastrophism is continuing or being reactivated. Maximum structural relief, measured from the tip of the pre-Cambrian, is estimated by Murray (1962) to be at least 27,000 ft. Elevation of the permit area ranges from 8000 feet plus in the northwestern portion to 6000 ft. near the proposed • truck loadout facilities. Exposed lithologies range in P6MIS 11PPLIGTIOR 2-~4 - 13 -