In the centre of the Rockies, occupying a large portion of Utah and adjacent States, is the "Great Basin," which, as remarked, has no drainage outlet for its waters. The geologists tell us that in ancient times this region was covered by two extensive lakes, one of them in the Pleistocene era occupying the now desert interior basin of Utah. This extinct lake, whose ancient shores can be distinctly traced, has been named Lake Bonneville. When at its greatest expansion, it covered twenty thousand square miles, and the waters were nearly a thousand feet deep, overflowing to the northward into a branch of Shoshoné River through a deep pass, and going thence to the Pacific. The waters of this lake, by climatic changes, gradually dwindled, the loss by evaporation overcame the rainfall supply, the overflow ceased, and then the lake dried up, revealing the desert bottom. Of its waters there now remain the Great Salt Lake of Utah, about eighty miles long and from thirty to fifty miles wide, very shallow, averaging only twenty feet depth, and not over fifty feet in the deepest place, having monotonously flat shores on the desert plateau, elevated forty-two hundred feet above the sea. Its dimensions vary according to the rainfall, the surface rising and falling in various periods of years. Several streams flow in, among them the Jordan River, forty miles long, draining Utah Lake to the southward. The waters are densely salt, varying from fourteen to twenty-two per cent. as the lake is high or low (compared with three to four per cent. in the ocean), and it is estimated to contain four hundred million tons of salt. Not a fish can live there excepting a small brine shrimp. A bath in the lake is novel, as the density makes the body very buoyant, easily floating head and shoulders above the water.