By the time the fur trade began to collapse in the 1840s, motivating them to change jobs, the trails they had explored and turned into reliable mule trails and improved gradually into wagon-capable freight roads combined to allow them to hire themselves as guides and scouts. As the fur trade declined, mountain man Robert Newell told Jim Bridger: "e are done with this life in the mountainsdone with wading in beaver dams, and freezing or starving alternatelydone with Indian trading and Indian fighting. The fur trade is dead in the Rocky Mountains, and it is no place for us now if ever it was." At the same time the great push west along the newly opened Oregon Trail built up from a trickle of settlers in 1841 to a steady stream in 1844–46 and then became a flood as the highly organized Mormon migration exploited the road to the Great Salt Lake discovered by mountain man Jim Bridger in 1847–48. The migration would explode in 1849's "The Forty-Niners" in response to the discovery of gold in California in 1848. Manifest Destiny had received a powerful push in the spring and summer of 1846 with the international treaties settling the ownership of the Pacific coast territories and Oregon Country on the United States.