A day or two later Fremont climbed out of the valley on the flank of the Wind River Mountains.

"We had reached a very elevated point," he says; "and in the valley below and among the hills were a number of lakes at different levels; some two or three hundred feet above others, with which they communicated by foaming torrents.

Even to our great height the roar of the cataracts came up, and we could see them leaping down in lines of snowy foam." Thus are the rills and the rivulets from the summits collected in these beautiful alpine lakes to give birth to the Colorado in white cascades, typical, at the very fountainhead, of the turbulence of the waters which have rent for themselves a trough of rock to the gulf.* Springing from these clear pools and seething falls, shadowed by sombre pines and granite crags, its course is run through plunging rapids to the final assault on the sea, where wide sand-barrens and desolation prevail.

Fremont understood this from his guides and says: "Lower down, from Brown's Hole to the southward, the river runs through lofty chasms, walled in by precipices of red rock." The descent "of the Colorado is but little known, and that little derived from vague report.

Three hundred miles of its lower part, as it approaches the Gulf of California, is reported to be smooth and tranquil; but its upper part is manifestly broken into many falls and rapids.