After a two-day respite at Travelers' Rest in early July, 1806, while Clark headed south towards Camp Fortunate, Lewis followed an Indian road up the Big Blackfoot River and over the Continental Divide towards the Great Falls of the Missouri, and back into buffalo country.
On July 7, just west of the divide, Lewis observed:
saw some sign of buffaloe early this morning in the valley where we encamped last evening from which it appears that the buffaloe do sometimes penetrate these mountains a few miles. we saw no buffaloe this evening. but much old appearance of dung, tracks, &c.
The following day, just east of the divide,
Josh. Fields saw two buffaloe below us some distance which are the first that have been seen. . . . much rejoiced at finding ourselves in the plains of the Missouri which abound with game.