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-21- <br /> The 100 to 200 foot thick Entrada Formation unconformably overlies the Maroon <br /> Formation. This formation is a red to tan sandstone, which forms slopes along <br /> the Grand Hogback. <br /> The Morrison Formation is of Jurrasic Age and overlies the Entrada Formation. <br /> This formation consists of a thick sequence of brightly colored, variegated <br /> shales, siltstones and sandstone. The shale units within this formation are <br /> highly erosive. <br /> The Cretaceous Age, Dakota Sandstone overlies the Morrison Formation. This <br /> unit consists of 100 to 150 feet of hard gray to buff colored sandstone, which <br /> is locally quartzitic. The Dakota sandstone is very resistant to erosion and <br /> is a prominent ridge former. <br /> Sedimentary rock strata exposed within the general area of the mines are the <br /> Cretaceous Age Mancos Shale Formation and Mesaverde Group, and the Tertiary <br /> Age Wasatch Formation. The Mancos shale consists of 3,000 to 4,000 feet of <br /> dark gray marine shales, and silty shales. The Mancos shale consists of two <br /> shale members divided by a limestone member. This formation is highly <br /> erosive, which results in the formation of broad valleys along the strike of <br /> this formation and an increase in total suspended solids in areas east of the <br /> mines. The saline nature of this marine shale formation results in an <br /> increase in total dissolved solids downstream and east of the mines. <br /> Conformably overlying the Mancos shale is the Mesaverde Group. This group is <br /> divided into two formations; the Iles Formation and the William Fork <br /> Formation. The Iles consists of the basal Cozzette sandstone member; the <br /> middle member consisting of shales, siltstones and fine-grained sandstones; <br /> and the Upper Rollins sandstones consist of medium to very fine-grained <br /> resistant sandstones. The two sandstones are ridge and cliff formers. <br /> The Williams Fork Formation consists of over 5,000 feet of sandstones, <br /> siltstones, shales and coals. This formation conformably overlies the Iles <br /> Formation and consists of marine and terrestrial deltaic deposits. The <br /> Williams Fork Formation is divided into three members; the lower coal-bearing <br /> Bowie member, the upper coal-bearing Paonia member, and the non-coal-bearing <br /> Barren member. <br /> The Bowie member is between 675 and 850 feet thick in the area of the mines, <br /> and is composed of four general submembers. In ascending order, these <br /> submembers are: 1) 420 to 480 foot thick coal-bearing Lower Bowie shale; 2) <br /> 30 to 130 foot thick Middle sandstone; 3) 150 to 200 foot thick Upper Bowie <br /> shale submember; and 4) 50 to 100 foot thick Upper Sandstone submember. The <br /> Lower Bowie coal-bearing shale submember contains several coal seams. These <br /> coal seams vary in thickness and lateral extent along the Grand Hogback. In <br /> the area around the Sunlight Mine, there are three minable coal seams; the <br /> "A-B" seam, the "C" seam, and the "D" seam. The "A-B" seam and the "C" seams <br />