Warren Angus Ferris (1810-1873) was a trapper, cartographer and diarist in the Rocky Mountains from 1830 to 1835. In 1829, he joined the American Fur Company to explore the Rocky Mountains. He kept a journal of his travels which were published as the book Life in the Rocky Mountains (1940), which gives an account of the Platte River Valley, Cache Valley, the area around Salt Lake City, and Snake River Country. Ferris found Native American guides and made a detour into what is today Yellowstone National Park.
In his journal Ferris gave one of the first descriptions of the geysers of the Yellowstone region: “From the surface of a rocky plain or table, burst forth columns of water of various dimensions, projected high in the air, accompanied by loud explosions, and sulphurous vapors, which were highly disagreeable to the smell. ... The largest of these wonderful fountains, projects a column of boiling water several feet in diameter, to the height of more than 150 feet.”