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Show 42 THE SHORTEST ROUTE TO CALIFORNIA. area have an average altitude of about five thousand five hundred feet, which is for much the larger portion of the area about fifteen hundred feet higher than said basin, and for the Mojave portion over four thousand feet higher, it will at once be apparent that, as a whole, the Basin should be conceived as an elevated central region extended over much the greater por-tion, and, in proximity to the circumference, sloping toward the sub- basins bordering the circumference. When this idea is entertained, and this extended central portion is in addition conceived of as being traversed by high and extensive ranges of moun-tains, on an average about fifteen miles apart, rang-ing north and south and forming intermediate valleys of commensurate lengths; bearing in mind at the same time that the order of depression of the basins is from Lake Sevier, where it is least, around suc-cessively by Great Salt Lake, Humboldt River Val-ley, Carson Lake, Walker's Lake, to the valley of the Mojave, where it is much the greatest; a very good mental daguerreotype can be had of the Great Basin inside of its inclosing mountains. From this descrip-tion we think it will be obvious that while the so-called Great Basin is in some small degree a Basin of lakes and streams, it is pre- eminently a Basin of moun-tains and valleys! In regard to the geological character of the mountains within the Great Basin, Captain Simpson's explora-tions show that from Camp Floyd west, as far as about Kobeh Valley, those of carboniferous origin pre-dominate; though over the desert proper, between Simpson's Springs and the Tots- arr Range, the igneous |