The formation of the intermountain lake environment in the area during the Eocene was a result of the Late Cretaceous Sevier orogeny to the west and the uplift of the Rocky Mountains during the Paleogene Laramide orogeny. The Eocene sedimentary basins thus received sediments from all directions. The Uinta uplift shed sediments north, east and south into the basins. The Winds RIver Mountains of west central Wyoming provided sediments from the north into the Green River basin. The Front Range, the Park Range, and the Sawatch Range of the Colorado Rockies provided sediments into the basins from the east. The Uncompahgre geanticline and the San Juan Mountains provided sediments from the south. To the west were the Wasatch Mountains of Utah and the ranges of eastern Idaho.