High and Low Water. The piles of driftwood found on the rocks in the Canyon reveal a difference of upwards of two hundred feet between high and low water. This, however, does not refer to the general condition of high water, but to exceptional cases. As, for instance, I myself once saw a mass of rock, the whole face of the cliff, containing doubtless millions of tons, fall into the trough of the stream. The whole course was at once dammed up, and the river rose sixty feet in one hour before the principal mass of rock was made topheavy by the power of the flood. Then it rolled over with the force of the millions of tons of water behind it, and crumbled as it rolled. The mighty wave dashed on, carrying everything before it. In less than another hour the rock mass had disappeared, and the water had resumed its normal level. A rise of fifty to seventy feet is not so very unusual in the heart of the gorge, where it is narrow and the waters would necessarily pile up. To see such a rise, without any evidence of a rain above, is a wonderful experience that one occasionally enjoys.