In geology, the Paradox Formation Is a Pennsylvanian age formation which consists of abundant evaporites with lesser interbedded shale, sandstone, and limestone. The evaporites are largely composed of gypsum, anhydrite, and halite. The formation is found mostly in the subsurface, but there are scattered exposures in anticlines in eastern Utah and western Colorado. These surface exposures occur in the Black Mesa, San Juan and Paradox Basins and the formation is found in the subsurface in southwestern Colorado, southeastern Utah, northeastern Arizona and northeastern New Mexico.