TIMOTHY O'SULLIVAN (1840-1882) Black Cañon, Colorado River, Looking Above from Camp 7. 1871. Albumen print, the image measuring 7⅞x10¾ inches (20x27.3 cm.), the two-toned Wheeler mount 16x20 inches (40.6x50.8 cm.), with O'Sullivan's printed credit, title, and plate number, and the U.S. Army Corps of Engineers Geological Survey credit and date, and the imprint of the War Department, Corps of Engineers, on mount recto.
