The Nugget Sandstone is a Late Triassic to Early Jurassic geologic formation exposed in Colorado, Idaho, Wyoming, and Utah that preserves a vivid record of ancient desert environments in the western United States. In Wyoming, it includes a lower interval of hematite-stained siltstone and thin-bedded sandstone beneath a cliff-forming upper sandstone with massive bedding and large cross-beds left by migrating dunes. Reaching about 86.9 meters, or 285 feet, thick, it is especially important for its fossil record, including theropod footprints and other trace fossils, with rarer body fossils also known. Together, its dune structures and trackways document both arid landscapes and the animals that crossed them.