bottom for the retention of the water in the valley deposits. So great is the capacity for imbibition of these desert plains that every drop of rain upon them, except such as is evaporated, is quickly drunk in, and all the mountain streams of the vast region, with three exceptions, completely disappear upon reaching them, and are known as "lost rivers" in the parlance of the West. Under the old erroneous idea that the mountain rocks contained the artesian waters, many hundred futile and costly experiments have been made by the Government, railroad corporations, and private individuals, in boring wells at the margins of these deserts, where the mountain rock was seen disappearing beneath the valley deposit, instead of seeking the lowest topographic point in the
Fig. 10.—Desert Travellers.
plains, and relying upon the unconsolidated formation of the desert as the probable source of water.
Within the past few years there have been many accidental demonstrations of this principle; and when it is generally understood, it is probable that in nearly every one of these now useless waste places at least a small quantity of water will be secured, and in many instances good flowing artesian wells. Wells of this character have been procured in great number in California, at Riverside and in the San Joaquin Valley, not one of which penetrates to the underlying floor of impervious mountain rock, but are all secured in the detrital valley deposit. Similar wells have been found in numbers in the Great Salt Lake Desert of Utah, and
