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-..• The Placita. bed conformably overlies a heavy <br /> sandstone member , the "Upper Sandstone, " which with- the <br /> remainder of the interburden, is considered to be adequate <br /> to protect the bed for possible future mining . <br /> A thin bed of coal thought to be the "Sun- <br /> shine" seam, occurs 50'-60 ' above the Placita in the Paonia <br /> Shale Member . It ranges from 18" thick on the north fork. of <br /> Dutch Creek, to around 4 ' on the middle fork of Coal Creek, <br /> at the west end of the basin. The seam may be related to <br /> the 15 ' thick seam mined (by another operator) at the Thompson <br /> Creek No . 3 mine, some 10 miles north of Coal Basin . <br /> e. Coal seam related strata <br /> The strata beneath the lowest coal seam <br />' ,• occuring in Coal Basin is the Rollins Sandstone member of <br /> the Mesaverde Formation. The Rollins is 120 ' to 140 ' thick. <br /> A shale tongue of 5' to 30 ' thickness , and identical to the <br /> underlieing shale, occurs within the Rollins some 25 to 75 <br /> feet above the base. The Rollins Sandstone varies in grain <br /> from very fine to coarse, but medium size predominates . <br /> Calcareous ironstone concretions , some as <br /> large as 20 'or 30' long , occur mainly below the shale tongue . <br /> The sandstone varies from feldspathic to lithic , and is <br /> cemented by calcite and silica until the top 5 to 20 feet , <br /> where a silica-clay matrix predominates . The silica-clay <br /> matrix is common throughout the western Upper Cretaceous <br /> • where coal directly overlies sandstone. <br /> 20 <br />