What name comes from a Native American word meaning "wolf's rump?
Later, uplift exposed the Moenkopi Formation to erosion and Utah became part of a large interior basin drained by north and northwest-flowing
rivers in the Upper Triassic. Shallow river deposition along with volcanic ash eventually became the mineral-rich Chinle Formation. The irregular contact zone, or unconformity, between the Chinle and the underlying Moenkopi can be seen between Rockville and Grafton in southwestern Utah.
Petrified wood and fossils of animals adapted to swampy environments, such as phytosaurs, lungfish, and lacustrine bivalves, have been found in this formation as well as conifer trees, cycads, ferns, and horsetails. Relatively plentiful uranium ore, such as carnotite and other uranium-bearing minerals, has also been found. The purple, pink, blue, white, yellow, gray, and red colored Chinle also contains shale, gypsum, limestone, sandstone, and quartz. Iron, manganese oxides and copper sulfide are often found filling gaps between pebbles.  Purplish slopes made of the Chinle can be seen above the town of Rockville.
The sand, gravel, and petrified wood which made up these deposits were later strongly cemented by dissolved silica (probably from volcanic ash from the west) in groundwater. Much of the bright coloration of the Chinle is due to soil formation during the Late Triassic. The lowermost member of the Chinle, the Shinarump, consists of a white, gray, and brown conglomerate made of coarse sandstone, and thin lenses of sandy mudstone, along with plentiful petrified wood. The Shinarump was laid down in braided streams that flowed through valleys eroded into the underlying Moenkopi Formation. This member of the Chinle forms prominent cliffs with thickness up to 200 feet (60 m), and its name comes from a Native American word meaning "wolf's rump" (a reference to the way this member erodes into gray, rounded hills).A succession of volcanic-ash-rich mudstone and sandstone with a thickness of 350-foot (110 m) make up the Petrified Forest Member of the Chinle, which was deposited by lakes, highly sinuous rivers and on the surrounding floodplains. This is the same bright, multicolored part of the Chinle that is exposed in Petrified Forest National Park and the Painted Desert. Petrified wood is, of course, also common in this member.
Shinarump