This early monumental survey took place in 1867, under the direction of Clarence King Geologist in charge of the exploration along the 40th Parallel, which spanned from Eastern Colorado to California. This expedition represented the first major attempt to map the area in detail, and was one of the first expeditions to use the medium of photography to capture images and activities of the expedition. Timothy O’Sullivan (1840-1882), known for his images of the Civil War, was the photographer for the survey. During his seven seasons (1867–1874) traversing the mountain and desert regions of the Western United States, he created one of the most influential visual accounts of the American interior. His photographs were subsequently reproduced in lithograph form by Julius Bien for inclusion in the published volumes reporting on the expedition.