Mount Rushmore still disputed on the basis of the 1868 Treaty of Fort Laramie (see section "Controversy" below). Among American settlers, the peak was known variously as Cougar Mountain, Sugarloaf Mountain, Slaughterhouse Mountain, and Keystone Cliffs. It was named Mount Rushmore during a prospecting expedition by Charles Rushmore, David Swanzey (husband of Carrie Ingalls), and Bill Challis. Historian Doane Robinson conceived the idea for Mount Rushmore in 1923 to promote tourism in South Dakota. In 1924, Robinson persuaded sculptor Gutzon Borglum to travel to the Black Hills region to ensure the carving could be accomplished. Borglum had been involved in sculpting the
Mount Rushmore average per year, enough to support abundant animal and plant life. Trees and other plants help to control surface runoff. Dikes, seeps, and springs help to dam up water that is flowing downhill, providing watering spots for animals. In addition, stones like sandstone and limestone help to hold groundwater, creating aquifers. A study of the fire scars present in tree ring samples indicates that forest fires occur in the ponderosa forests surrounding Mount Rushmore around every 27 years. Large fires are not common. Most events have been ground fires that serve to clear forest debris. The area is a climax