The focus of the monument is a large promontory, or bluff, that rises 800 feet (244 metres) above the river. Consisting of layers of sandstone, volcanic ash, and siltstone, the bluff is part of an escarpment and was a prominent landmark on the Oregon (Oregon Trail) and Mormon trails. It remains a memorial to those who on foot, on horseback, and in covered wagons moved America westward (westward movement). The formation is named for Hiram Scott, a fur-company clerk, who died near the bluff in 1828. A museum at the base of the bluff displays the history of the pioneer travelers. The prairie habitat surrounding the bluff supports deer, rabbits, prairie dogs, foxes, coyotes, and rattlesnakes.