Geological Survey geological map of the San Mateo Quadrangle, California, issued in October 1913. This map covers portions of San Francisco, San Mateo, and the surrounding Peninsula region, including San Francisco Bay, San Bruno Mountain, Half Moon Bay, Ocean Beach, and numerous historic place names and geological formations. Printed in color and professionally mounted on cloth backing for durability, a common practice used by universities, libraries, and geology departments during the early 20th century. The reverse bears a stamp from Michigan State College Department of Geology and Geography, indicating institutional use. Map features detailed geological formations, fault lines, topographic information, contour lines, and period transportation routes. An excellent piece for collectors of California history, geology, cartography, USGS materials, or antique scientific maps. Condition: Vintage condition with age-related toning, edge wear, and fraying to the cloth backing. Please review all photographs carefully for exact condition. Approximate size: 18″ x 22″. Original 1913 issue, not a modern reproduction.