The Wind River Canyon provides a unique slice through geologic time, exposing rocks deposited when life was beginning and when Wyoming was covered by a sea with a tropical climate similar to the Gulf of Mexico today. Over the last 100 million years, the Owl Creek Mountains were uplifted, folded, faulted, and then eroded by the Wind River to form this spectacular canyon. Because the rocks were folded and tilted from a horizontal to a slight angle toward the north, the canyon reveals geologic formations in age from Precambrian, nearly 2.9 billion years old, to Triassic, over 200 million years old, spanning more than 2.7 billion years. Exposed rock types include granite, basalt, metamorphosed volcanic rocks such as amphibolite and schist, limestone, dolomite, sandstone, siltstone, and shale.