The lake bed is now the seat of an important industry--the gathering of the borax and its refining. There are extensive buildings at one spot upon its border, and men come and go across the blinding white surface. A twenty-mule team dragging three huge wagons creeps slowly along the base of the distant mountains, but all that can be distinguished is a cloud of dust. [Illustration: FIG. 45.--FREIGHTING BORAX ACROSS THE DESERT] The slow crumbling of the rocks, and the setting free of those constituents which are soluble, the work of the streams in gathering the rock waste into the lakes, the dry air and the heat of the long summer days, have all conspired together to give us these valuable deposits in the dried-up lakes of the Great Basin. No portion of the earth seems to be without value to man. The great bodies of water are convenient highways. The rich valleys and timbered mountains offer useful products. Even the deserts, where living things of every description find the struggle for existence very hard, become indispensable. If the climate in the Great Basin had been moist, the salts would not have been preserved, but would have been carried away to the ocean, from which only common salt could have been recovered in commercial quantities. [Illustration: FIG. 46.--MUSHROOM ROCK, PYRAMID LAKE Formed of calcareous tufa] The crossing of the Great Basin was dreaded by the early emigrants on their way to the Pacific coast. In many cases the locations of the few springs and water-courses were unknown, and the journey over the vast barren stretches was fraught with danger. Stand upon a mountain in the desert some clear day in summer and you will see range after range, with intervening sandy wastes, stretching away to the horizon. The air below is tremulous with heat, and every living thing that can move has sought the shade of some rock or cliff. The plants seem almost dead, for the little springs, hidden at rare intervals in the deep canons, are of no use to them. What transformations would be wrought upon these desert slopes if it were possible for the soil to receive and retain large quantities of water! Forest-covered mountains, green hillsides, rippling streams, lakes, farms, orchards, and towns would appear as if by magic. FREMONT'S ADVENTURES IN THE GREAT BASIN Fremont, "the Pathfinder," did greater service than any other man in making known the geographic features of the Cordilleran region. In the fifth decade of the last century, while California still belonged to Mexico and the pioneers were turning their attention to the Oregon country, Fremont organized and conducted three exploring expeditions under the direction of the government. When in California upon the third expedition he took part in the skirmishes which resulted in the transference of this section to the United States.