This rare, large map is considered by Wheat to be a landmark in the mapping of the region and "one of the most beautiful maps every published by the Army." According to Wheat there are several reasons for its importance. First, it is the first to show a trail to the junction of the Green and Grand Rivers. Second, it is the first to correctly establish the relationship between the San Juan and Colorado Rivers. Third, he praises the map for its depiction of numerous routes of other explorers. Finally, it demonstrates the culmination of the process developed by Egloffstein to convey the idea of altitude. The process used a combination of extremely fine lines and applying acid to the plate for varying times, thus giving the map a remarkable 3-dimensional realism unmatched in the period. The map covers Arizona, Utah, New Mexico and about 30% of Colorado.

The map is accompanied by Capt. Malcomb's "Report of the Exploring Expedition from Santa Fe, New Mexico, to the Junction of the Grand and Green River", produced in 1859 but not issued until 1876 due to the Civil War. The report includes 22 plates (11 tissue-guarded chromolithographic landscape views, 3 b&w views, and 8 plates of fossil specimens). Color plates drawn by J. J. Young from field sketches provided by J. S. Newberry. Quarto, 152 pp., hardbound in brown cloth.

References: Wheat (TMW) #983; Howes #M-179.

Condition: B+

Condition code is for the map, which is very good with light offsetting, several small fold separations that have been closed on verso with archival tape, and a few shot splits at the fold junctions. Plates are very good to fine with some dampstaining in the margins, and text is toned. Title page is missing and a former owner's bookplate is on the front pastedown. Covers have average wear and the spine is sunned.