Stratigraphic reference sections of the Wasatch, Green River, and Bridger (Washakie) Formations were measured on outcrops in the Green River and Washakie basins adjacent to the Rock Springs uplift in southwest Wyoming. The Washakie basin reference section is 7,939 feet thick and consists of 708 beds that were measured, described, and sampled to evaluate the origin, composition, and paleontology of the rocks. The reference section in the Green River basin is 6,587 feet thick and consists of 624 beds that were measured and described but were not sampled; this section was measured to correlate rock units with those in the Washakie basin. Columnar sections that have been prepared combine information on the Stratigraphic nomenclature, age, depositional environments, lithologies, and fossils of each bed in the reference sections. Eocene strata in the Green River and Washakie basins have been correlated biostratigraphically, chronostratigraphically, and lithostratigraphically. The time boundaries of the lower, middle, and upper Eocene rocks in the reference sections are located partly from biostratigraphic investigations and partly from chronostratigraphic investigations. The time boundaries agree with North American land mammal ages, which were used in the report because of their historical precedence. Major Stratigraphic units and key marker beds correlated between the reference sections appeared remarkably similar in thickness and lithology, which suggests that most depositional events were contemporaneous in both basins. One major difference between the sections is that the upper 875 feet of upper Eocene rocks in the Washakie basin is missing by nondeposition or by post-Eocene erosion in the Green River basin. Rocks sampled in the Washakie basin reference section were examined petrographically and were analyzed using heavy mineral separations, X-ray techniques, and assays. The mineralogy suggests that source rocks in the lower part of the Eocene were mostly of plutonic origin and that source rocks in the upper part of the Eocene were mostly of volcanic origin. Economically significant beds of oil shale and zeolite were identified by the analyses. Fossil pollen Manuscript approved for publication November 30, 1990. collected from 22 beds was used to identify plants that characterize five successive climates present in the Washakie basin during the Eocene Epoch. Dl D2 WASATCH, GREEN RIVER, AND BRIDGER (WASHAKIE) FORMATIONS BOUNDARY OF GREATER GREEN RIVER BASIN Lonetree McKinnon 7(530 50 MILES FIGURE 1. General locations (shaded) of Eocene reference sections, Green River and Washakie basins. For detailed locations, see index maps on plates 1 and 2. EOCENE ROCKS IN GREEN RIVER AND WASHAKIE BASINS, SOUTHWEST WYOMING D3 ACCESSIBILITY OF THE REFERENCE SECTIONS The reference section in the Green River basin is accessible by Wyoming Highway 530 south of Green River, Wyo., and Wyoming Highway 373 southwest of Rock Springs, Wyo. The reference section in the Washakie basin is accessible by Wyoming Highway 430 southeast of Rock ...