In central Wyoming, Independence Rock stood along an east-west passageway through the Rockies created by geological events in which granite peaks rose, sank, were buried in sand and ashy sediments, and were later exposed by erosion as the Sweetwater Valley formed. The route was used first by game animals, Native Americans, and fur trappers, and by mid-century by wagon train and handcart emigrants, stagecoach passengers, and Pony Express riders traveling the Oregon Trail. For some, the rock marked the halfway point in a 2000-mile journey from the Missouri River to the West Coast, and those who reached it early in July celebrated Independence Day. In July, 1841, Jesuit missionary Pierre Jean De Smet called it the famous Independence Rock, said it was named because the first travelers to name it arrived there on the anniversary of the United States' emancipation from Great Britain, recorded that his party cut their names on the south side beneath the initials I.H.S., and, because of the many names, dates, and Indian warriors' hieroglyphics on it, called it 'The Great Record of the Desert.'