GeoSight— Fantasy Canyon
Geologic Information: The sandstone layer in which the pinnacles, pillars, arches, and knobs of Fantasy Canyon are formed consists of ancient river channel sediments. The underlying and overlying rock layers sandwiching the sandstone layer, and creating scenic badland topography around the canyon, are finer grained floodplain deposits.
During the Eocene Epoch, 55 to 34 million years ago, the Fantasy Canyon area was at the fringe of a vast subtropical lake – Lake Uinta – that at peak level stretched from the Wasatch Plateau to western Colorado. The lake was in a drying phase and retreating westward by the end of the Eocene.