Fossil Mountain (Wyoming)

Fossil Mountain (10,921 feet (3,329 m)) is located in the Teton Range, within the Jedediah Smith Wilderness of Caribou-Targhee National Forest, U.S. state of Wyoming.

As mapped by J. D. Love and others, the peak of Fossil Mountain consists of relatively flat-lying beds of the Mississippian Madison Limestone and underlying Devonian Darby Formation. Underlying the Darby Formation and exposed in shear cliffs and floors of glacially modified valleys are the Ordovician Bighorn Dolomite, Cambrian Gallatin Formation, Gros Ventre Formation and Flathead Sandstone. In all, there is about 2,700 feet (820 m) of lower and middle Paleozoic sedimentary strata exposed within the area of Fossil Mountain.

The study of the sedimentary strata within the Teton Range, shows that these strata consist mostly of limestones and dolomites. The Madison Limestone consists of a basal, dark-colored, fine-grained dolomitic limestones overlain by hundreds of feet of gray limestone that is classified as fossiliferous oosparite and fossiliferous pelsparite. Abundant fossils of shells and corals, which are protected by federal laws, have been found in the Madison Limestone at Fossil Mountain. Underlying the Madison Limestone, the Darby Formation consists mostly of dolomites and limestones that commonly contain discontinuous layers of calcareous shale or sandstone.