Featured in this lot is this General Report mandated by The War Department for the Colorado Exploring Expedition lead by Lieutenant J.C. Ives, of teh Topographical Engineers of 1857-1858 and published in 1861. In late 1857, Lieutenant Joseph Christmas Ives of the U.S. Army Corps of Topographical Engineers was tasked with evaluating the navigability of the Colorado River as a potential supply route to Utah amid tensions leading up to the Utah War. Funded by the 1857 Army Appropriation Act, the expedition launched from Robinson’s Landing at the mouth of the Colorado on December 31, 1857, aboard a compact 54-foot sternwheeler named the Explorer, which had been built in Philadelphia, shipped in pieces to California, and assembled on site. Beginning in early 1858, Explorer steamed upriver from Fort Yuma, enduring slow progress and numerous groundings witnessed with amusement by the Yuma and Cocopah tribes, who nicknamed it the “chiquito boat.” Nonetheless, the craft made it to Black Canyon (near today’s Hoover Dam), marking the upper limit of navigable steam travel. From there, Ives and a select crew continued overland into the Grand Canyon floor, becoming the first party of Euro-Americans to descend into its depths, though Ives famously dismissed the region as “altogether valueless,” a misjudgment in hindsight. The expedition’s secondary, scientific mandate involved geological, botanical, zoological, and ethnographic exploration. Naturalist John S. Newberry collected specimens later named in his honor, including new plant species, while the artists Baldwin Möllhausen and Frederick von Egloffstein produced detailed illustrations and topographic mapping of the landscape, Indigenous tribes, and river terrain. Ultimately, the expedition returned downstream, then traveled overland from Beale’s Crossing through Fort Defiance, mapping and documenting a vast region and its Native communities. The resulting 1861 report, Report upon the Colorado River of the West, became a foundational geographical and hydrographic survey, complete with maps, lithographs, and appendices covering everything from river currents to local Indian customs. The condition of this of this two volume set is preserved with some wear to the outside cover of the books with some binding repair and shows browning to the pages consistent with age. The measurements of this pair of books is 11 3/4" x 9 1/2". The collective weight of these books is 7lb 2oz.