Wyoming to Eastern British Columbia, stand cordons of stupendous mountains, the western outposts of the great Continental Divide. These constitute one spur after another, from whose profound cañons issues river after river to swell the torrents of the turbid and impetuous Snake on its thousand-mile journey to join the Columbia. Among these tributary streams are the Payette, the Boisé, the Salmon, and the Clearwater. Yet farther north, beyond the system of the Snake, are the Bitter Root, the Missoula, the Pend Oreille, the Spokane, and the Kootenai (we follow here the American spelling, the Canadian being Kootenay), with almost innumerable affluents, draining the huge labyrinths of the Bitter Root Mountains and the Silver Bow.
Thus our northward flight carries us to the international boundary in latitude 49 degrees.
Far beyond that parallel stretches chain after chain of divisions of the great Continental Range, the Selkirks, the Gold Range, Purcell's Range, sky-piercing heights, snow-clad and glaciated. Up and down these interlocking chains the Columbia and the Kootenai, with their great lakes and unexplored tributaries, seem to be playing at hide-and-seek with each other. These rivers form here one of the most singular geographical phenomena of the world, for so strangely are the parallel chains of mountains tilted that the Kootenai, rising in a small lake on the western flank of the main chain of the Canadian Rockies and flowing south, passes within a mile of the source of the Columbia at Columbia Lake, separated only by a nearly level valley. Connection, in fact, is so easy that a canal once joined the two rivers. From that point of con-
