"The North Knobs UCG facility is located on the west flank of the Rawlins Uplift approximately eight miles northwest of Rawlins in Carbon County, Wyoming on the eastern side of Sec. 11, T21N, R89W. The Fort Union formation in this area has been informally subdivided into three members (Davis, et .al., no date). The lower member which is thought to unconformably overly the Cretaceous Medicine Bow Formation , is characterized by conglomeratic and coarse-grained sandstones. The middle member, which contains the coal seams of interest, is composed of interbedded sandstone, siltstone, mudstone, claystone and coal. This member is, in turn, overlain by alternating silty sandstone and mudstone of the upper member. The total thickness of the Fort Union Formation is approximately 3,273 feet at the North Knobs UCG site (Davis, et aI., date). These strata are here interpreted as braided and meandering river deposits and associated floodplain, swamp and crevasse splay deposits."