Inscription: Inscribed in the negative: "91"; printed on mount, upper edge: "WAR DEPARTMENT [+ insignia]// Explorations in Nevada and Arizona. Expedition of 1871. Lieut. Geo. M. Wheeler, Com'd'g."; lower edge: "T. H. O'Sullivan, Phot.// COLORADO RIVER SERIES// WALL IN THE GRAND CAÑON// No. 91."
No. 91, Colorado River Series.