On the summit and sides of the mountain were thousands of lakes of clear water, which received their supply from the masses of snow which are collecting throughout the winter on the mountain ranges, filling the gorges and half burying the forests. In summer the snow melted and poured down the mountain sides in millions of cascades, eventually forming the Colorado River, which grew into a mad torrent ere it reached the Gulf of California. Eventful indeed would be the history of these waters if traced from their starting point. Some of these streams ran across arid plateaus, being fed in their course by intermittent showers. Each year their channels became deeper and deeper, cutting their way out of solid rock. Every river, brook, creek and rill ran into a cañon, so that these vast areas were traversed by a labyrinth of deep gorges hewn out of the rock by the ever-flowing streams. If the Colorado plateau had been in such a country as the District of Columbia, the land lying adjacent to the river courses would have been washed down by the rains and streams, and instead of cañons there would now be a broad system of valleys. It was an error to regard that Colorado plateau as a region of great erosion or degradation. It was a vast system of cañons, caused by the water eating its way through the hard rock, with lofty stone walls on either side. Major Powell said that in 1867 and 1868 he had explored the Grand River and other tributaries of the Colorado, and these expeditions thrilled him with a desire to explore the vast cañons of the Colorado River itself. Accordingly in May, 1869, he started for this purpose with a small party of men and four boats from a point a few miles below where now the Union and Pacific Railroad crosses Yukon River. The first forty or fifty miles of their course was through low cañons, cut through the green and alcove lands of that region. Their course was southward. As they descended the river, a mountain seemed to stand athwart their path, and into this mountain the river penetrated. They followed around the base for a hundred miles or so, meeting the river beyond. Now, why had not the river flowed _round_ the mountain instead of cutting its way _through_? The answer was exceedingly simple. Because the river was there before the mountain, and had the right of way, keeping steadfastly on its southward course, across which the lands had been gradually elevated. These land upheavals had taken place very slowly, enabling the river to force its passage as the land rose inch by inch.