A complex, relatively high velocity and likely braided stream system covered most of southern Utah in the Late Triassic. Various members of the resulting Chinle Formation are found over much of the Colorado Plateaus. Logs, sand, mud and wind-transported volcanic ash from distant eruptions were mixed by streams as they migrated over a subsiding basin to form the Chinle. Uranium salts accumulated in this formation in economically extractable quantities and petrified wood was formed (petrification was probably aided by the presence of volcanic ash). Chinle members represented in the Capitol Reef area are (from oldest to youngest):