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anticline structure and corresponding syncline to the south consist of thousands of feet of marine <br />deposited sediments of Cretaceous age <br />To the south of the anticline, the axis of the Collum Syncline, a downward fold, passes directly <br />through the permit area, striking north 70 degrees west and dipping from 0 to 20 degrees to the <br />North. In the southeastern comer of the permit area, neaz Streeter Fill, the Collum Syncline is <br />influenced by the Elkhorn Syncline and results in strata having an eastward dip and north-south <br />strike (see Map 7 and Figure 1 in the Permit). <br />There appears to be no evidence of faulting in the permit azea; however, linear features that may <br />be fault-related have been observed from aerial photographs. These lineations trend northwest <br />with a strike approximately north 70 degrees west, north 45 degrees west and north 30 degrees <br />east, with a near vertical inclination. <br />The coal bearing stratum of interest to the Colowyo operation aze stratigraphically located in the <br />Mesaverde Group within the Williams Fork Formation of upper Cretaceous age. The Williams <br />Fork consists of alternating beds of sandstone, sandy shale, carbonaceous shale and coal. The <br />coal section to be mined is a 392-foot interval in the Fairfield Member of the Williams Fork <br />Formation. The quality of the coal seams is midway between bituminous and sub-bituminous. <br />These coal beds are underlain by 9,000 feet of Mesozoic and 4,500 feet of Paleozoic sediments. <br />The Willianrs Fork Formation is estimated to be 1,600 feet thick in the permit area and is <br />underlain by the ridge-forming Trout Creek sandstone member of the Iles Formation. <br />The coal seams mined in the Colowyo operation are identified on page 15 above. Overburden <br />material consists of a sequence of sedimentary claystones, siltstones, shales and <br />carbonaceous-silty shales. These sediments aze typical of the cyclothems deposited along the <br />western interior of North America during Late Cretaceous time. The site-specific stratigraphy is <br />described in Exhibit 6 and on Map 8 of the Permit. There are four seams below the "F" seam <br />which cannot be economically mined by surface mining methods. These seams are described in <br />16 Revised October 30, 1997 <br />