Map and profile in pocket. Chapters 1-9 of pt. 1, with six chapters added, were pub. later (Meadville, Pa., 1895) under title: Canyons of the Colorado, by J.W. Powell ... pt. 1. History of the explorations of the cañons of the Colorado [May 24-Sept. 20, 1869] Report on a trip to the mouth of the Dirty Devil River [May 27-July 11, 1872] by A.H. Thompson.--pt. 2. On the physical features of the valley of the Colorado.--pt. 3. Zoology: Abstracts of results of a study of the genera Geomys and Thomomys, by Elliott Coues. Addendum A. The cranial and dental characters of Geomydæ, by Elliott Coues. Addendum B. Notes on the salamander of Florida (Geomys Tueza) by G.B. Goode. The present report does not include a narrative of the second descent of the river in 1871-1872, a detailed account of which may be found in F.S. Dellenbaugh's A canyon voyage, New York, 1908.