Marvine, A.R., 1875, Report on the geology of route from St. George, Utah, to Gila River, Arizona examined in 1871, Part II, in U.S. Army Engineer Department, Report upon geographical and geological explorations and surveys west of the one hundreth meridian, in charge of First Lieut. Geo. M. Wheeler - v. 3, Geology: Washington, D.C., U.S. Government Printing Office, p. 189-225.