Fossil Butte

This view is of Fossil Butte in Fossil Butte National Monument in southwestern Wyoming. The Monument was established in 1972 to preserve one of the richest fossil localities in the world. The park encompasses a rolling landscape developed on eroding sedimentary rocks that formed about 50 million years ago during the Eocene Epoch. The sedimentary section exposed in the park preserves deposits that accumulated in a lakebed and floodplain environments. Fossils of fish, alligators, bats, turtles, dog-sized horses, insects, and many other species of plants and animals suggest that the region was a subtropical, freshwater basin when the sediments accumulated over about a 2 million-year period. The fossils and sediments preserve a fantastic record of the ancient biological communities and environment for this period of Earth history (McGrew and Casilliano, 1975, NPS, 2006; NPS, 2009).