This early monumental survey took place in 1867, under the direction of Clarence King who was only 25 years old when he was appointed 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 King survey. His photographs were subsequently reproduced in lithograph form by Julius Bien for inclusion in the published volumes reporting on the expedition. Many of O’Sullivan’s original photographs from the 40th Parallel expedition are now in the collection of The George Eastman House in New York and are a unique archive depicting the American West. In 1879, the United States Geological Survey was established and appointed Clarence King its first director. In 1881, King resigned this position to pursue other scientific interests leaving John Wesley Powell (1834-1902) as his successor.