Fossil Mountain, at the south end of Utah’s Confusion Range, became known for exceptionally abundant Ordovician fossils exposed on its slopes and cliffs rather than for its height. Early twentieth-century collecting by Frank Beckwith and Charles Kelly brought attention to its rich marine invertebrate fossil beds and helped attract both visitors and professional researchers. Later work by university geologists, Charles E. Resser, and Hintze made the mountain an important site for paleontological and stratigraphic study, including designation of the east slope as the type section for the Kanosh Shale. Its layered rocks, about 485 to 458 million years old, preserve diverse shallow-marine life and record changing coastal environments during the Ordovician.