Pg. 5-7, sheet 1 (figs. 1-3, geol. map), sheet 2. Overland Member, upper member of Fort Union Formation. Present in Washakie, Sand Wash, and Great Divide basins, Carbon County, southernmost Wyoming, and Moffat County, northwesternmost Colorado. In places, forms spectacular badlands. Called "basal sandy unit" and "upper shaly unit" of Fort Union by Tyler and McMurry (1994, Univ. Texas-Austin Bur. Econ. Geol. Rpt. Inv., no. 220). Divided into (ascending): (1) basal sandstone zone, light-gray, coarse-grained sandstones; (2) fine-grained interval, light-gray, silty sandstone, sandy siltstone, and mudstone; and (3) Cherokee coal zone. Thickness 925 feet at type section. Regional unconformity separates Overland from underlying Blue Gap Member or, where absent, the China Butte Member (both new; of Fort Union). Unconformably underlies Wasatch Formation, locally underlies Battle Spring Formation equivalent. In eastern Washakie and southeastern Great Divide basins, age is late middle and late Paleocene, based on palynomorphs (zones P3 or P4 through P6 of Nichols and Ott, 1978, Palynology, v. 2, p. 93–112); vertebrate fossils, from at or near base of member, indicate a latest Torrejonian to early Tiffanian age (see Hettinger and others, 1991, USGS Misc. Inv. Ser. Map I-2151).
Type section: in area referred to locally as the "Cedars," located astride the Dad arch near WY State Highway 789. Base of section about 2,150 ft from east line and 1,300 ft from south line, in sec. 34, T. 17 N., R. 92 W.; top is 600 ft from west line and 1,150 ft from south line of sec. 34, T. 17 N., R. 92 W., Doty Mountain 7.5-minute quadrangle Carbon Co., southernmost WY. Named from Overland Trail, which passes across exposures in Doty Mountain 7.5-minute quadrangle.

Source: Publication.