DescriptionFourteen miles west of Kemmerer on US 30, Fossil Butte National Monument rises nearly 1,000 feet above the Twin Creek Valley. The buff-to-white beds of the Green River Formation contain one of the world's largest deposits of the fossils of freshwater fish that lived 50 million years ago. Fossils of mammals, reptiles, fish, insects and plants can be seen at the visitor center; a video presentation also is available.
A self-guiding hiking trail, 2.5 miles long, leads to the site of a historic fossil quarry, and a 1.5-mile trail takes visitors through an aspen tree grove. Interpretive programs are offered June through August.
Allow 2 hours, 30 minutes minimum. Grounds open all year but may be snow-covered Oct.-Apr. Visitor center daily 9-5:30, May-Sept.; 8-4:30, rest of year. Closed winter holidays. Free. Phone (307) 877-4455.