Fossil Butte National Monument is a unit of the National Park Service located 15 miles west of Kemmerer, Wyoming; the national monument was established on October 23, 1972. The site preserves the best paleontological record of Tertiary aquatic communities in North America and possibly the World, within the 50-million-year-old Green River lake beds.
Fossils preserved, including fish, alligators, bats, turtles, dog-sized horses, insects, and many other species of plants and animals suggest that the region was a low, subtropical, freshwater basin when the sediments accumulated, over about a 2 million-year period.
The Visitor Center features over 80 fossils and fossil casts on exhibit, including fish, a crocodile, turtle, bats, birds, insects and plants. A 13-minute video is shown about the fossils found at the site and what scientists have learned. Interactive exhibits let visitors create fossil rubbings to take home, and a computer program discusses fossils, geology and the current natural history of the monument.