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to a short distance east of the mine. Throughout Coal Creek, Snowshoe <br />Creek, and Anthracite Creek Areas, in Townships 13 and 14 South, Range <br />89 West, the position of the Hawks Nest Coal is marked only by stringers <br />and thin beds, which are grouped as the Hawks Nest Coal Zone. <br />The Hawks Nest Coal Zone is overlain by a sedimentary sequence about 100 <br />to 200 feet thick, comprised dominantely of sandstone, which crops out <br />predominately. The top of this unit has been selected as the boundary <br />between the Upper Coal Member and the overlying Barren Member. A study <br />of the geological logs shows that the vertical intervals separating the <br />coal seams within each of the coal members varies considerably. Where <br />the interval between coal seams is great, a larger portion of sandstone <br />is present between the coals. This relation may be explained either by <br />the more rapid rate of deposition of sand as compared with clay, or by <br />the lower compaction ratio of sand. Either factor would cause a greater <br />separation of coal seams by sandstone than by shale. <br />• Barren Member. The upper part of the Mesaverde Formation lying above <br />the thick sandstone that overlies the Hawks Nest Coal horizon, is <br />referred to as the Barren Member. It consists of interbedded and <br />interlensed sandstone and shale of varying thicknesses. The general <br />character of these barren upper beds is the same as in the coal bearing <br />Members, except that the sandstone beds are more lenticular and the <br />shale zones are essentially barren of coal. The thickness of the Barren <br />Member varies greatly owing to the post-Mesa Verde erosion, but is <br />originally much in excess of 1,500 feet. Field evidence suggests a <br />southward truncation of the entire Mesa Verde Formation by <br />post-Cretaceous tilting and subsequent erosion. <br />Ohio Creek Conglomerate <br />The Ohio Creek Conglomerate of Tertiary Age rests on the Mesaverde <br />Formation and is separated from it by an irregular unconformity which <br />indicates some channeling. The Formation consists of light colored <br />• sandstone, locally containing abundant pebbles of chert, jasperoid <br />2.04-17 <br />