Mount Diablo is located at the north end of the Mount Diablo Range, which is the central group of the Coast Ranges. It stands between the great central valley of California and the Pacific Coast adjacent to San Francisco. Rising thus from near sea level to an elevation of 3,849 feet, it is in view from the eastern slopes of the Sierra Nevada Mountains to the Golden Gate and is a reference land mark for central and northern California. Mount Diablo proper is an ovate mass of metamorphic and igneous rocks, fifteen square miles in area, protruding through the center of a great anticlinal fold fifty miles long. Cretaceous and Tertiary sedimentary rocks in the flanks of the anticline make parallel ridges of erosion 1,500 to 2,000 feet high on the northeast and southwest sides of the mountain.
Surveys of Jurassic, Cretaceous, and Tertiary sedimentary rocks of . . .