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6 <br /> has a total thickness of 1200 to 1600 feet. The base of the Raton consists <br /> of a buff to gray pebble conglomerate a few inches to a few tens of feet <br /> thick. Bedding within the basal conglomerate is not prominent, but cross <br /> 1 <br /> lamination may be locally well developed. Most of the Raton consists of <br /> very fine to medium grained sandstones including arkose, orthoquartzite <br /> and graywake interbedded with gray to dark gray siltstone and shale. Coal <br /> mined by CF&I is located near the middle of the Raton. The upper 100 to <br /> 200 feet of the formation tends to be coarser grained, somewhat more arkosic <br /> and with lighter colored shales. The primary source area for the Raton <br /> is the igneous-metamorphic terrain to the west. <br /> J The Raton formation in the study area may be characterized as stream <br /> deposits including channel-point bar facies, floodplain deposits and swamp <br /> deposits. Excellent examples of channel sands are exposed in the walls of <br /> the Picketwire Valley. Local intraformational unconformaties and abrupt <br /> facies changes result in a great deal of lateral heterogeniety. <br /> l <br /> The Paleocene, Poison Canyon formation unconformably overlies the <br /> Raton and has a thickness of approximately 600 feet in the region. It <br /> occurs as small patches, probably no thicker than 200 feet near the study <br /> area. The formation consists of massive, very coarse arkosic sandstone, <br /> pebble conglomerate, and thick shale. These conglomerates and coarse sand- <br /> stones are buff to gray in color and weather to a reddish brown and contain <br /> granite, gneiss and quartzite lithic clasts. The shale is locally silty <br /> and carbonaceous. <br /> Sills and dikes associated with Tertiary volcanism intrude the Vermejo <br /> r� <br /> i� <br />