The California Coast Ranges, from the region around Santa Rosa north of San Francisco Bay to the San Fernando Valley near Los Angeles, and between the San Joaquin Valley and the coast, offer an unusual and interesting type of physiography. The region may extend south into the peninsular ranges as well as north of Santa Rosa, but the author knows of no other ranges of this type in this country.
The material for these notes was obtained in studies connected with the work of the Seismological Society of America in locating the active faults of the Coast Ranges. One summer, 1922, was spent in general reconnaissance work covering a good part of the region between Santa Rosa and San Luis Obispo. The autumn of the previous year, 1921, was spent in a detailed study of the southern Santa Cruz Range and the summer of 1923 in a similar study . . .