In this manner it came about that a river of ice occupied the canon in which the old lake lay, and, displacing its waters, scraped and ground out the bottom and sides. The moving ice deposited the waste material at the lower end of the canon, where it joined the Columbia River, the canon of which was also occupied by a glacier coming from farther north. When the glacier began to retreat up the Chelan canon, it left a great mass of rock debris, forming a dam between its basin and the Columbia. After the ice had disappeared, water collected in the canon above the dam, and the narrow, deep lake was formed, enclosed within granite walls. As the snows melted, forests spread over the mountains, the bear, deer, and mountain goats came back again, while the streams, bringing down earth and rocks, began their work of filling up the lake. This task they will succeed in accomplishing some day unless something unforeseen happens to prevent. A valley, composed partly of meadow and partly of boulder-covered slopes, will then have taken the place of the lake. THE NATIVE INHABITANTS OF THE PACIFIC SLOPE The explorers and early settlers found a native race occupying nearly every portion of our continent. These people had many characteristics in common and were all called Indians. It is believed that they came originally from Asia, but their migration and scattering occurred so long ago that they have become divided into many groups, each having its own language and customs. In the western portion of the country, where the surface is broken by numerous barriers, such as mountains and deserts, almost every valley was found to be occupied by a distinct group of Indians called a "tribe." The language of each tribe differed so much from the languages of adjoining tribes that they could with difficulty understand one another. These tribes were almost continually at war. The Indians upon the Pacific slope were generally found to be inferior in most respects to those living in the central and eastern portions of the continent. One might suppose that the tribes possessing the fair and fertile valleys of California would be the most advanced in civilization, but such was not the case. Many of them were among the most degraded upon the continent. They seemed unable to adapt themselves to the white man and his ways, and in the older settled districts they have now nearly disappeared. In the newer portions of the Northwest and along the coast toward Alaska the Indians have not yet come into so direct contact with the white men, and remain more nearly in their primitive condition.