In Utah, upon the Uintah Indian reservation, are found veins of asphaltum of remarkable purity, to which the name 'Gilsonite' has been given. It has been found very useful for insulation and a great variety of purposes, but has only been used in combination with softer material for paving.
Among the coast ranges of California there are deposits of asphaltum and siliceous asphalte of vast extent. At Santa Cruz, to the east and west of Santa Barbara, near the coast near San Buena Ventura and Los Angeles, on the Ojai ranch, and at Asphalto, in Kern County, the principal ones are found. Those of commercial value are at the works of the Alcatraz Company, west of Santa Barbara, and near Asphalto. At the works of the Alcatraz Company the bitumen is dissolved in a
solvent and conveyed through pipes some thirty miles to the coast, where the solvent is removed and the bitumen prepared for shipment.
At Asphalto, on the north side of the Coast range, in Kern County, the asphaltum occurs nearly pure in veins of great extent that have been mined to a depth of more than three hundred feet. From these statements it will be seen that the deposits of asphaltum and asphalte in the United States are of vast extent and variety.
While the bitumen in these different deposits in different parts of the world bears a generic relation, there are specific differences between the different varieties that render some of them more desirable for certain purposes than the others. The purest asphaltums are brilliant black, brittle solids that consist of compounds of carbon and hydrogen with small proportions of oxygen, sulphur and nitrogen. The latter
