Early as was the season, the men suffered much from mosquitoes. Spring kept company with the expedition. Herds of deer, elk, buffaloes and antelopes were seen grazing on the rich grass, and there seemed no end to swans and geese. Passing the alkali regions, the party reached, in the latter part of April, the mouth of a large river, to which they gave the name of Yellowstone. Joseph Fields, of Kentucky, ascended it for eight miles, and was the first white man to do so. Rains, high winds and cold weather welcomed them into the hills of Montana, and often the boats had to be dragged along the banks by means of elk-skin cords. They were thus laboriously making their way when, as has been shown, they were met by Deerfoot and the Shelton brothers at the mouth of the Musselshell River.
The story of the Lewis and Clark expedition, therefore, ended for George and Victor Shelton at the point named. It will not be uninteresting, however, to sum up the history of one of the most memorable enterprises connected with the development of the West. Captains Lewis and Clark gained a great deal of valuable knowledge from the boys, who had traversed a large part of the region which they intended to explore. The excellent memories and the marked intelligence of the youths were admired by the officers.
A few days after the meeting between the two parties Lewis climbed to the top of the highest elevation north of the river and gained his first view of the Rocky Mountains, known at that time as the Stony Mountains. All the numerous streams were described and named. It has been charged against the explorers that they were lacking in sentiment and imagination, for most of the names thus given by them have been supplanted by others, but it cannot be said that these changes have always been an improvement.
On the second day of summer the explorers had to face a puzzling problem. A large branch flowing from the north was so similar to the Missouri that it seemed it must be that river, while the one hitherto accepted as such bore to the south. Which was the branch that, according to the reports of the Indians, had its rise in the Rocky Mountains, near the source of the Columbia? To settle the question the party divided, one ascending either branch. Upon reuniting it was agreed that the south branch was the real Missouri. The northern stream was named the Maria. This was another of the few instances in which the title given by the explorers stuck.