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-s- l tinned by Woodward-Clyde Consultants (1978). As all borings 1 were augered, it was apparently difficult to define when the J top of the bedrock was encountered. It is quite possible 1 that a substantial thickness of the soils is, in fact, weath- ered bedrock of the Mesaverde Formation. It is thus theo- retically possible that the thickness of soils at the upper 1 (and also the lower) bench is much less than the numbers presented above. Woodward-Clyde Consultants believe that the top of the rock may lie within about 5 feet of the topo- l graphical surface. J It is evident that the estimation of the soil cover thickness and of its character is not sufficient at the present time; it will be necessary to investigate this item in the future. Our experience with exploratory drilling at the site confirms that the estimation of the top of bedrock is very ' difficult and that it requires special drilling methods. The lithology of the barren member which underlies the upper bench down to the top of the F coal seam is of sig- nificance for the purpose of our study. Although no drilling has been performed for this purpose, logs of borings per- formed by ARCO are available. We have reviewed and studied ' logs of 18 borings which were made available to us (boring Nos. 84, 85, 99, 96, 87, 82, 86, 92, 96, 89, 93, 95, 98, 94, ' 90, 97, 100, and 101). This evaluation enables the conclusion that there is no apparent continuity between layers of one 1 lithological type even for a very short distance. The layers seem to have a lenticular character and they cannot be ' followed for any significant distance. This appears to be in accordance with the origin of the barren member which was deposited in a landward fluvial environment. ' ~EONroao ca+su~nrw, wc.