Desolate, indeed, must have appeared the surroundings of the lake, with its salt-incrusted borders, as the Mormon emigrants gained the summit of the Wasatch Range and looked out over the vast expanse to the west. But as the slopes at the foot of the mountains seemed capable of producing food for their support, they stopped and made their homes there. Now in this same region, after half a century, one can ride for many miles through as beautiful and highly cultivated a country as the sun ever looked down upon. In the early days the barren plains were broken only by mountains almost as barren, which rose from them like the islands from the surface of the Great Salt Lake. The only pleasing prospect was toward the east, where stood the steep and rugged Wasatch Range, with its snow-capped peaks. From its deep canons issued large streams of pure, cold water, which flowed undisturbed across the brush-covered slopes, then unbroken by irrigating ditches, and at last were lost in the salt lake. One might think that streams of water apparently so pure would at last freshen the lake, but in reality they are carrying along invisible particles of mineral matter which add to its saltness day by day. The dry air steals away the water from the lake as fast as it runs in, but cannot take the minerals which it holds in solution. Great Salt Lake is still considered very large, but at one time it was ten times its present size, while still longer ago there was no lake at all. Without a basin there can be no lake, and at that far-away time, as we have already learned, the Great Basin did not exist, and the streams, if there were any, ran away to the ocean without hindrance. When the Great Basin was formed by a breaking and bending of the crust of the earth, many a stream lost its connection with the ocean and went to work filling up the smaller basins, thus giving rise to the lakes which have already been described. The largest of these bodies of water, and in some respects the most interesting, is Great Salt Lake. [Illustration: FIG. 53.--OLD SHORE LINE OF LAKE BONNEVILLE Foot of the Wasatch Range] This lake, lying close to the lofty Wasatch Range, received so much water from numerous streams during the Glacial period that it slowly spread over thousands of square miles, overrunning the desert valleys and making islands of the scattered mountain ranges. It extended from north to south across Utah, into southern Idaho and almost to the Arizona line, until this body of water, which arose from so small beginnings, had become a veritable inland sea, three hundred miles long, one hundred miles wide, and one thousand feet deep.