From 1867-1872, geologist Clarence King (1842-1901) led the Geological Exploration of the 40th Parallel. The survey covered a large expanse of land, a total area 100 by 800 miles from the eastern edge of California to Wyoming. Timothy H. O’Sullivan (1840-1882) was the primary photographer for the 1867, 1868, 1869, and 1872 expeditions. This photograph of a lake in the Uinta Mountains in Utah was taken by O'Sullivan in 1869. The photograph shows pine trees and rocky cliffs surrounding the small alpine lake. The number 115 can be seen in the lower left corner, possibly corresponding with the original negative number. Printed on the front of the photograph mount: "U.S. Engineer Department. Geological Exploration. Fortieth Parallel. T.H. O'Sullivan, Photographer." Hand-written note in lower right corner, likely by photographer, reads: "View, Uinta Lake, [illegible]."