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<br />The Cretaceous Yermejo Formation conformably overlies the Cretaceous <br />Trinidad formation. Typically, the Vermejo Formation consists of three <br />lithologies; slightly arkosic sandstone, carbonaceous shale, and coal. <br />The Vermejo rapidly thickens west of the town of Cokedale to over <br />300 feet. <br />The Cretaceous to Paleocene aged Raton Formation is exposed at the <br />surface in the study area. It rests unconformably above the <br />Vermejo Formation and has a total thickness of 1,200 to 1,600 ft. The <br />base of the Raton Formation consists of a buff to gray pebble <br />conglomerate a few inches to several feet in thickness. <br />Most of the Raton Formation is composed of very fine to medium grained <br />sandstones including arkose, orthoquartzite and graywacke which are <br />interbedded with gray to dark gray siltstone and shale. The upper 100 to <br />200 feet of the formation tends to contain coarse grained, arkosic <br />sandstones and light colored shales. <br />The coal seam which is being mined at the Golden Eagle Mine is the <br />Maxwell seam; the New Elk Mine is located in the Allen seam. Both the <br />Allen and Maxwell seams are located in the middle of the Raton Formation <br />of Cretaceous age. The Allen seam lies stratigraphically beneath the <br />Maxwell coal seam. The seams are separated by a thin interbedded strata <br />which varies in thickness from a few feet in the New Elk Mine to a few <br />tens of feet in the Golden Eagle Mine. <br />The Paleocene Poison Canyon formation unconformably overlies the <br />Raton Formation and has a thickness of approximately 600 feet in the <br />study area. It occurs as sm311 isolated outcrops, probably no thicker <br />than 200 feet near the study area. This formation consists of massive, <br />very coarse arkosic sandstone, pebble conglomerates, and thick shales. <br />Sills and dikes associated with Tertiary vulcanism intrude the Vermejo <br />and Raton Formations and are visible in the Picketwire Valley. They <br />range in thickness from a few inches to greater than 20 feet and are <br />primarily composed of basalt. <br />Quaternary deposits consist primarily of river terrace and floodplain <br />deposits associated with the Purgatoire River and its tributaries. The <br />study area contains two levels of rock benches that formerly may have <br />been referred to in the literature as Beshoar and Barilla pediments. The <br />applicant's consultant has interpreted these as strath terraces with an <br />alluvial veneer. These strath terraces are located approximately 90 to <br />170 feet above the river in the study area. They have been eroded from <br />shale and siltstone containing thin interbeds of fine to very fine, silty <br />sandstone. The overlying alluvium has a maximum thickness of <br />approximately 35 feet and is composed of predominantly silt and sand <br />containing pebbles and occasional boulders. <br />Two levels of alluvial terraces were identified adjacent to the <br />Purgatoire River. These terraces are located 5 to 10 feet and 40 to <br />50 feet above the river in the study area and have been investigated by <br />Powell, 1952. They are composed of relatively unweathered, gray to light <br />tan alluvium overlain by medium to dark brown sandy overbook deposits. <br />-10- <br />