[ Photographs ] O'sullivan, Timothy Entrance to Black Canon, Colorado River, from above. Albumen print, 8x 10.25inches, on the original Wheeler Survey mount, with the War Department, Corps of Engineers and Wheeler Expedition credits, plate number 10,

[ Photographs ] O'sullivan, Timothy Entrance to Black Canon, Colorado River, from above. Albumen print, 8x 10.25inches, on the original Wheeler Survey mount, with the War Department, Corps of Engineers and Wheeler Expedition credits, plate number 10, and title printed on mount recto. 1871