Volcanic rocks of the El Modeno Area, Orange County, California Yerkes, R. F. 1923- creator author. Geological Survey (U.S.) issuing body. text bibliography dcu 1957 monographic eng remote 1 online resource (27 unnumbered pages) : illustrations, maps + 2 plates. by Robert F. Yerkes. Title from title screen (viewed September 26, 2014). "Description of extrusive pyroclastic and flow rocks of El Modeno volcanics of middle to late Miocene age." Includes bibliographical references (page 331) and index. n-us-ca Geology, Stratigraphic Miocene Igneous rocks California Orange County Volcanic ash, tuff, etc California Orange County Orange County (Calif.) Geology, Stratigraphic Igneous rocks Miocene Geologic Epoch Volcanic ash, tuff, etc California Orange County From 10 to 25 million years ago fast I 19.16:274-L I 19.16:274-L Volcanic rocks of the El Modeno Area, Orange County, California Yerkes, R. F., 1923-. (OCoLC)2701284 Geological Survey professional paper ; 274-L Shorter contributions to general geology https://purl.fdlp.gov/GPO/gpo86136 COP 140929 20211120182637.0 in00003972603 eng