Currently uranium is found in Triassic-age rocks of the Colorado Plateau. Dinosaurs and primitive mammals appear. Ago Description of Events Permian 290 Deposition continues in the Oquirrh and Paradox basins. Red rocks form in the Paradox basin of sediments shed from the Uncompahgre highland. Pennsylvanian 330 Seas containing fusulinids, brachiopods, and conodonts cover most of Utah.
Sediments continue to accumulate in the Oquirrh basin.
The Paradox basin and the adjacent Uncompahgre highland develop in southeastern Utah. Salt, potash, and organic-rich shale accumulate in the shallow, restricted Paradox basin. Pennsylvanian-age reservoir rocks contain large volumes of oil and gas. Reptiles originate during this period. Mississippian 360 Warm, shallow seas rich with life cover Utah for most of this period.