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~J <br />2.04.6 GEOLOGY DESCRIPTION <br />......................................................................................................................................................................... <br />........................................................................................................................................................................... <br />.................................................................................................................................................................. <br />The stratigraphy of the permit and adjacent area consists of the <br />Cretaceous Mesaverde Group. The Mesaverde Group is comprised of <br />the following units, in ascending order, Castlegate Sandstone, <br />Buck Tongue of the Mancos Shale, Sego Sandstone, Mount Garfield' <br />Formation and Hunter Canyon Formation. The coal seams that were <br />mined in previous permit terms (Anchor and Cameo seams) were <br />mined in the lower portion of the Mount Garfield Formation. <br />The Mount Garfield Formation consists of interbedded shales, <br />sandstones, siltsones and coal. The sandstone units range in <br />thickness from 2 to 40 feet and generally average less than 10 <br />feet in thickness and are laterally discontinuous. <br />The Mesaverde Group is underlain by the Mancos Shale formation. <br />The Mancos Shale is exposed along the lower portion of the Book <br />Cliffs and underlies much of the Grand Valley. This formation is ~ <br />• impermeable and will prevent any mingling of waters between the <br />strata of the Mesa Verde and any lower strata. <br />• <br />7/iy~12 2/13 <br />