Fossil Butte National Monument is located near Kemmerer, Wyoming. It containes Eocene Epoch (56 to 34 million years ago) animal and plant fossils associated with Fossil Lake—the smallest lake of the three great lakes which were then present in what are now Wyoming, Utah, and Colorado. Preserved fossils include fish, alligators, bats, turtles, dog-sized horses, insects, and many other species of plants and animals. Sediments accumulated over about a 2 million-year period.
