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• The Jack O'Lantern Seam is a low sulfur coal ranging in thickness from 4 <br />to 8 feet consisting of 3 recognizable coal units: <br />Upper Jack 1.5' <br />Upper Parting 0.2' <br />Middle Jack 4.0' <br />Lower Parting 0.1' <br />Lower Jack 1.5' <br />coal <br />bone and sandstone <br />coal <br />bone / carbonaceous shale <br />coal <br />Raton Formation. Unconformably overlying the Vermejo Formation are the <br />sediments of the Raton Formation. This unit consists of two members, a <br />basal sandstone and overlying sequence of interbedded mud and sandstones. <br />The basal sandstone is massive, cross-stratified, and white to light gray <br />in color with bentonitic cementation and extensive rounded to sub angular <br />conglomerate inclusions. Thickness of the basal unit varies from 60 to <br />90 feet. <br />The erosional base of this unit marks the top of the Vermejo Formation in <br />the Southfield mine area. Though coal bearing in the Raton Basin to the <br />south, the upper Raton Formation in the Canon City Basin contains no <br />significant coal and consists of a series of fluvial mudstones, sand, and <br />siltstones. The Raton Formation has a total thickness of approximately <br />650 feet. <br />Poison Canyon Formation. Unconformably overlying the Raton Formation <br />are the sediments of the Poison Canyon Formation. This formation consists <br />of 200 feet or more of alternating beds of mudstone and sandstone with a <br />basal conglomeratic sandstone. This formation is barren of coal and has <br />been mapped as part of the Raton Formation. Depositionally and physically <br />similar to the Raton, it is difficult to distinguish between the two <br />formations. <br /> Boulder Colluvium/Alluvium. Covering most of the topographic ridges and <br /> flats in and around the Southfield mine area are a series of Pleistocene <br />. boulder colluvial/alluvial deposits. The USGS (Scott 8 Taylor, 1974) <br />identified three stratigraphic horizons of boulder colluvial/alluvium in <br />the Southfield area: the Verdos, Rocky Flats, and Nussbaum alluvium. <br />2.04.6-7 <br />