Pg. 3-4, sheet 1 (figs. 1-3, geol. map), sheet 2. China Butte Member, lower member of Fort Union Formation. Present in Washakie, Sand Wash, and Great Divide basins, Carbon County, southernmost Wyoming, and Moffat County, northwesternmost Colorado. Previously called lower zone (or part) of Fort Union. Consists of a basal conglomerate overlain by stacked, fining-upward cycles of sandstone, mudstone, carbonaceous shale, and coal. Thickness about 1,060 feet at type section. Includes (ascending) Red Rim (and equivalent), Wild Cow, lower Separation Creek, Olson Draw equivalent, lower Muddy Creek, upper Muddy Creek, and Fillmore Ranch coal zones. Unconformably overlies Red Rim Member (new) of Lance Formation; basal conglomerate marks regional unconformity separating Tertiary from Cretaceous age rocks. Underlies Blue Gap Member or, where absent, underlies Overland Member (both new; of Fort Union). Correlates with coal-bearing rocks in Sand Wash basin described by Tyler and McMurry (1994, Univ. Texas-Austin Bur. Econ. Geol. Rpt. Inv., no. 220). Age is early Paleocene, based on fossils. Samples from basal coal beds yielded palynomorphs typical of zone P2 of Nichols and Ott (1978, Palynology, v. 2, p. 93–112). Report includes geologic map, measured sections, correlation chart, cross sections.
Type section: in area referred to locally as the "Cedars," located astride Dad arch near WY State Highway 789. Base of section 1,200 ft from west line and 1,000 ft from south line of sec. 3, T. 16 N., R. 92 W., Doty Mountain 7.5-min quadrangle, Carbon County, southern WY; top lies on sec. line between secs. 4 and 9, 1,950 ft from southeast corner of sec. 4, T. 16 N., R. 92 W., Duck Lake 7.5-min quadrangle, Carbon Co., southern WY. Named from China Butte in northeastern part of Doty Mountain 7.5-min quadrangle.

Source: Publication.