Fossil Mountain, a 10,921-foot peak in Wyoming’s Teton Range, is important chiefly for its exposed geology rather than its shape. Around the mountain, relatively flat-lying Madison Limestone sits above the Darby Formation, while cliffs and glacial valleys reveal older Ordovician and Cambrian rocks, together showing about 2,700 feet of lower and middle Paleozoic sedimentary strata. The limestones and dolomites include fossil-rich beds with shells and corals that gave the mountain its name and are protected by federal law. West of the peak, Fossil Mountain Ice Cave preserves layered ice and sediment that record local temperatures over the past 175 years, while also posing hazards and suffering damage from visitors.