Permian ammonoids from western United States

All the known Permian material from the Great Basin and adjacent areas is considered. Representatives of Properrinites, Crimites, and Daraelites are described from the Wolfcampian of Nevada. From the Leonardian are recorded Perrinites, Popanoceras?, and Pseudogastrioceras in Arizona; Pseudogastrioceras in Utah; also Perrinites and Spirolegoceras, n. gen., in Idaho. An account of a new species of Stacheoceras from the Middle or Upper Permian of northern California is included. N THE region of the Great Basin, Late Paleozoic strata are extensively devel- oped anc well exposed. However, the only widespread ammonoid assemblage that they have yielded is Upper Mississippian in age, Pennsylvanian forms are entirely unknown, and Permian specimens are rare. During the present study an effort has been made to locate and investigate every reported occurrence of Permian ammonoids in the states west of the Rockies. Results