We sleep another night by the spring on the summit of the Kaibab, and next day we go around to Point Sublime and then push on to the very verge of the Kaibab, where we can overlook the canyon at the mouth of the Little Colorado. The day is a repetition of the glorious day before, and at night we sleep again at the same spring. In the morning we turn to the northeast and descend from Kaibab to the back of Marble Canyon and cross it at the foot of the Vermilion Cliffs, and find our packers camped at Jacob's Pool, where a spring bursts from the cliff at the summit of a great hill of talus. In the camp we find a score or more of Indians, who have joined us here by previous appointment, as we need their services in crossing the river.
On the last day of September we follow the Vermilion Cliffs around to the mouth of the Paria. Here the cliffs present a wall of about 2,000 feet in height,--above, orange and vermilion, but below, chocolate, purple, and gray in alternating bands of rainbow brightness. The cliffs are cut with deep side canyons, and the rainbow hills below are destitute of vegetation. At night we camp on the bank of the Colorado River, on the same spot where our boat-party had camped the year before. Leaving the party in charge of Mr. Graves and Mr. Bishop, while they are building a ferryboat, I take some Indians to explore the canyon of the Paria. We find steep walls on either side, but a rather broad, flat plain below, through which the muddy river winds its way over quicksands. This stream we have to cross from time to time, and we find the quicksands treacherous and our horses floundering in the trembling masses.
These broad canyons, or canyon valleys, are carved by the streams in obedience to an interesting law of corrasion. Where the declivity of the stream is great the river corrades, or cuts its bottom deeper and still deeper, ever forming narrow clefts, but when the stream has cut its channel down until the declivity is greatly reduced, it can no longer carry the load of sand with which it is fed, but drops
DANCE PARAPHERNALIA FROM TUSAYAN.
a part of it on the way. Wherever it drops it in this manner a sand bank is formed. Now the effect of this sand bar is to turn the course of the river against the wall or bank, and as it unloads in one place it cuts in another below and loads itself again; so it unloads itself and forms bars, and loads itself with more material to form bars, and the process of vertical cutting is transformed into a process of lateral cutting. The rate of cutting is greatly increased thereby, but the wear is on the sides and not on the bottom. So long as the declivity of the stream is great, the greater the load of sand carried the greater the rate of vertical cutting; but when the declivity is reduced, so that part of the load is thrown down, vertical cutting is changed to lateral and the rate of corrosion multiplied thereby. Now this broad valley canyon, or "box canyon," as such channels are usually called in the country, has been formed by the stream itself, cutting its channel at first vertically and afterwards laterally, and so a great flood-plain is formed.