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• <br />CLIFF HOUSE SANDSTONE <br />The Cliff House Sandstone is [he upper formation of [he Mesa Verde Grou <br />area and is of marine origin. It generally consists of irregular to lenticular ledges o <br />medium-grained calcareous sandstone enclosed in softer argillaceous fine sandstor <br />silty shale. <br />Like the Point Lookout sandstone, the Cliff House sandstone is reported to <br />size in an eastward direction. Ten to fifteen miles east of the project area the form <br />soft dark-gray mudstone and fine sandy silt-shale with an occasional very thin lent. <br />in the lower part. <br />The Cliff House sandstone has an average thickness of 350 feet throughout <br />area. It shows a slight eastward thinning, probably due to the decrease in coarse cl <br />increase in compactable fine sediments. <br />LEWISSHALE <br />The Lewis Shale conformably overlies the Cliff House sandstone and cons <br />black homogeneous clay shale with scattered concretions of dense argillaceous lin <br />few thin seams of bentonite in the upper part. The formation is reported to be abo <br />with the basal contact being very sharp with black flaky clay-shale resting on gray <br />shale of the Cliff House sandstone. <br />STRUCTURE <br />The geologic structure of the Hesperus area is characterized by gentle sou <br />• from seven to two degrees away from the structurally high La Plata Mountains to <br />probable that a small amount of faulting is present in the vicinity of the town of H <br />a displacement of 33 feet has been reported in the Monarch mine about one mile r <br />Results of exploration drilling conducted in [he area have not revealed significant <br /> <br />2.04.6 page 3 <br />in the Hesperus <br />hard Yine to <br />mudstone, and <br />decrease in grain <br />uion is composed of <br />I of fine sandstone <br />most of the project <br />istics and the <br />of dark gray to <br />tone and with a <br />1,825 feet thick <br />idstone or sandy <br />and dips ranging <br />north. It is <br />eras. A fault with <br />yeast of Hesperus. <br />November 1993 <br />