"In 1869 David Folsom, Charles Cook, and William Peterson explored the Yellowstone area. On September 22, they measured the height of the falls. They took Peterson's ball of twine and a forked stick and reeled it out. Cook was at the top of the falls, while Peterson was below giving instructions to Cook. They were unsuccessful in securing an accurate measurement due to the turbulence of the water and mist from the water. They were more successful measuring the height of the Upper Fall which they concluded was 115 feet. The actual height of the Upper Fall is considered to be 109 feet. Further down the river, a few miles from the Lower Fall, is the Bannock Ford. The Bannock Ford was used by the Bannocks, the Nez Perces, and the Shoshonis to cross the Yellowstone on their way east to Montana's and Wyoming's "Buffalo Country" from 1840 through the 1870s.
"Henry D. Washburn was a former major general in the Union army who used his influence to obtain the post of surveyor general for Montana Territory. Nathaniel P. Langford, who later became the first Yellowstone Park Superintendent, visited with Jay Cooke in Philadelphia where he presented a case for the exploration of Yellowstone and how this would benefit the Northern Pacific Railroad. The Washburn party was formed; and Nathaniel P. Langford, who had lost his job as tax collector for Montana, Lieutentant Doane and others would form the group. While the group was in the Upper Geyser Basin, they named several of the geysers including Grotto Geyser."