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-la- The Maroon Formation conformably overlies the Eagle Valley Formation. This formation consists of over 2,000 feet of red to tan arkoslc sandstones, stltstone, conglomerates and locally some limestones. The 100 to 200 foot thick Entrada Formation unconformably overlies the Maroon Formation. This formation 1s a red to tan sandstone, which forms slopes along the Grand Hogback. The Morrison Formation is of Jurrasic Age and overlies the Entrada Formation. This formation consists of a thick sequence of brightly colored, variegated shales, slltstones and sandstone. The shale units within this formation are highly erosive. The Cretaceous Age, Dakota Sandstone overlies the Morrison Formation. This unit consists of 100 to 150 feet of hard gray to buff colored sandstone, which is locally quartzltic. The Dakota sandstone is very resistant to erosion and 15 a prominent ridge former. Sedimentary rock strata exposed within the general area of the mines are the Cretaceous Age Mancos Shale Formation and Mesaverde Group, and the Tertiary Age Wasatch Formation. The Mancos shale consists of 3,000 to 4,000 feet of dark gray marine shales, and silty shales. The Mancos shale consists of two shale members divided by a limestone member. This formation 1s highly erosive, which results in the formation of broad valleys along the strike of this formation and an increase in total suspended solids 1n areas east of the mines. The saline nature of this marine shale formation results to an increase in total dissolved solids downstream and east of the mines. Conformably overlying the Mancos shale is the Mesaverde Group. This group is divided into two formations; the Iles Formation and the William Fork formation. The Iles consists of the basal Cozette sandstone member; the middle member consisting of shales, slltstones and fine-grained sandstones; and the upper Rollins sandstones consist of medium to very fine-grained resistant sandstones. The two sandstones are ridge and cliff formers. The Williams Fork Formation co slltstones, shales and coals. Iles Formation and consists of The Williams Fork Formation 15 coal-bearing Bowie member, the non-coal-bearing Barren member tslsts of over 5,000 feet of sandstones, This formation conformably overlies the marine and terrestrial deltaic deposits. divided into three members; the lower upper coal-bearing Paonia member, and the The Bowie member 1s between 675 and '850 feet thick in the area of the mines, and is composed of four general submembers. In ascending order, these submembers are: 1) 420 to 480 foot thick coal-bearing lower Bowie shale; 2) 30 to 130 foot thick Middle sandstone; 3) 150 to 200 foot thick Upper Bowie shale submember; and 4) 50 to 100 foot thick Upper sandstone submember. The lower Bowie coal-bearing shale submember contains Several coal seams. These coal seams vary in thickness and lateral extent along ,'