This rare pair of maps represents the earliest geological maps of the Grand Canyon region prepared as part of one of the most important exploring efforts of the American Southwest. Ives published his explorations in a series of four maps, two topographical and two geological; these being the rarer geological maps. In his book Mapping of the Trans-Mississippi West, Carl Wheat devotes several pages to the topographical versions of these maps saying they are two of the best created by the remarkable F.W. von Egloffstein. They were engraved using his system that imparts the appearance of depth to the topography and nearly mimics a satellite image. A remarkable accomplishment for the time. The maps were prepared by J.S. Newberry M.D., Geologist to the Expedition, with topography by von Egloffstein and lettering by F. Courtenay. Each approximately measures the size given as listed.

The maps are bound in the original report "Colorado Exploring Expedition, Lieutenant J.C. Ives, Topographical Engineers, 1857-58. Geological Report. By Dr. J.S. Newberry, Geologist to the Expedition," dated 1861. The quarto report contains the 154 pp. geology report with the two maps, three full page lithographic plates, three paleontology plates, and 27 wood engraved views within the text, followed by a 30 pp. section on Botany and Zoology. This report contains the official geological results of the first of three great explorations of the Colorado River undertaken by the Federal government during the mid-19th century (Ives, Macomb and Powell). Ives used the steamboat Explorer (disassembled in Philadelphia and shipped via the Isthmus of Panama to the mouth of the Colorado River where it was reassembled) to transport his party. According to Goetzmann, "the comprehensive observations of Ives and the scientists accompanying his expedition were a distinct contribution to the knowledge of a little-known and superficially explored region." Newberry correctly attributed the Canyon's existence to fluvial erosion, but erred in unraveling its geologic history. Very uncommon to find the maps and report together and intact, more so given only a portion of the Senate issued report contained the geological maps.

The first map shows the topography and geology of the lower Colorado River in four panels (each about 8.5" x 14"), beginning at the Gulf and ending in Black Canon at Fortification Rock. Locates and names Pt. Invincible, Ogden's Landing, Fort Yuma, Lighthouse rock, The Needles, the location of Beale's Crossing, Bullshead (today's Bullhead City), Painted Canon, Fortification Rock, and much more. Numerous rapids are noted including Roaring Rapid 3 large rocks & one sunken rock below, and Violent Rapid with rocks on both sides. Geological formations are shown in only two colors thus reflecting Newberry’s interpretation of limited geological complexity in the lower canyon.

The second map details the region around the Grand Canyon and Little Colorado River. It shows the river from about Needles (Whipple's Crossing and Mojave Canyon) north through Black Canyon, to the Little Colorado and then north to beyond the survey's limit as the riverbed fades to nothing. The map locates Fort Defiance, Campbell's Pass, Zuni, Moquis (Hopi) Pueblos, San Francisco Springs (Flagstaff), Las Vegas, the Mormon Road, numerous Indian tribes, and much more. Several important exploration routes and trails are shown including The Old Spanish Trail, Whipple's trail 1854-4 and Beale's trail. A very unusual map for its use of pastel colors including pink for delineating the seven geological formations of the main canyon region as conceived by Newberry..

References: Marcou & Marcou #784.

Condition: B+

Both with some light and occasional marginal foxing, the map images are fine less a binding trim tear (2") that is closed on verso. The report is disbound and generally very good, but toward the back there is bookworm damage to spine area at back of the book: no plates affected.