On reaching the Peckágama summit, the channel of the Mississippi was found to flow more directly from the west, with a comparatively sluggish current. But the most distinctive trait of this part of the river was found to consist of a series of extensive savannahs, through which the river displays itself in the most elaborate windings. The junction of the Leech Lake branch takes place at this plateau, at the computed distance of fifty-five miles above the falls. After passing this point, the course of the river is again, generally, from the north-west, about forty-five miles to Lake Winnipec, a handsome body of clear water, estimated to be ten miles broad. The course of the ascent is then west, for about fifty miles, at which distance the river is found expanded into a more considerable lake, presenting an area of limpid water of, perhaps, 120 square miles. This sheet, which has subsequently been found to be the largest expansion of the Mississippi, is since denominated Cass Lake. It was the highest point reached. The party entered it on the 21st of July. The question of pursuing the stream further, was then submitted by Gov. Cass, to the gentlemen composing his party. Anxious as all were to see the actual source of so celebrated a stream, their wishes were controlled by circumstances. Inconveniences had been felt from leaving the supplies at so considerable a distance below, and as the waters were found to be low, and the preparations inadequate for a journey of indefinite extent, a decisive opinion was expressed in favor of a return from this point. This decision was immediately carried into effect. From the best information that could be obtained, the Mississippi was represented to have its origin in a lake called _La Biche_, supposed to be sixty miles distant, in a north-west direction. Upon this estimate, the length of the river was computed to be 3038 miles, and by a series of approximate estimates, its altitude placed at 1330 feet above the Atlantic. Numerous rapids and lakes were, however, stated to exist in this remote part of the stream, and a degree of vagueness and uncertainty exhibited in relation to it, which evinced, that the traders, who were relied on for information, either, had seldom frequented it, or preserved an indefinite recollection of its geographical features.