Painted Rock Mountains The Gila River crosses all of southern Arizona from southwest New Mexico, and is the drainage for about 1/2 of Arizona (the south). The highest elevation in the mountains is "unnamed" at , and is located at the central & east region of the range. (The range has many northwest-by-southeast ridgelines.) Painted Rock Mountains The Painted Rocks Mountains are a short 15-mile (24 km) long mountain range of the north-central Sonoran Desert southwest of Phoenix, Arizona and in southwest Maricopa County. The Gila River flows through the central-north end of the range. The famous Painted Rock Petroglyph Site lies at
Painted Desert (Arizona) desert is composed of stratified layers of easily erodible siltstone, mudstone, and shale of the Triassic Chinle Formation. These fine grained rock layers contain abundant iron and manganese compounds which provide the pigments for the various colors of the region. Thin resistant lacustrine limestone layers and volcanic flows cap the mesas. Numerous layers of silicic volcanic ash occur in the Chinle and provide the silica for the petrified logs of the area. The erosion of these layers has resulted in the formation of the badlands topography of the region. In the southern portions of the desert the remains of a