La Mesa, Poway, and SW1/4 Escondido quadrangles
by
Michael P. Kennedy and Gary L. Peterson
In 1965 the California Division of Mines and Geology, in cooperation with the City of San Diego, "egan a comprehensive geologic investigation of the greater San Diego metropolitan area. This report deals with the geology of the eastern half of that investigation. A similar report has been written on the western half and includes the geology of the Del Mar, La Jolla, and Point Loma quadrangles (Kennedy, 1975). The La Mesa, Poway, and SW 114 Escondido .quadrangles comprise more than 25 percent of the greater San Diego metropolitan area. This area is underlain by San Diego's richest sand, gravel, and crushed stone resources, deemed feasibly extractable in today's market for use in the Mission Valley, Mira Mesa, Poway, and Escondido suburbs. These resources and others, including rich clay deposits, are being rapidly covered by urban development. The clay deposits, which are locally expansible, in turn constitute a serious geologic hazard to development. The geologic mapping and detailed descriptions of the rock units are intended to be used as aids in planning for land use and future development. The stratigraphic relationship between the rock units underlying the study area and those that underlie the area to the west (discussed by Kennedy, 1975) are shown in figure 2. Previous geologic investigations that have been especially useful in this study include a ground water investigation by A.J. Ellis (1919), a stratigraphic and paleontologic study of the La Jolla quadrangle by M.A. Hanna (1926), two papers on geology and paleontology of the San Diego area by L.G. Hertlein and U.S. Grant l[V (1939, 1941, and a monograph on the mineral resources of San Diego County by F.H. Weber, Jr. (1963).
The authors would like to extend special thanks to D.M. Morton and G.W. Moore of the United States Geological Survey for their suggestions and contributions pertinent to the results of this study. Acknowledgment is due also to M.O. Woodburne, P.K. Morton, G.B. Cleveland, F.H. Weber, Jr., C.H. Gray, Jr., M.A. Murphy, J.P. Kern, R.G. Strand, and Y.H. Smitter for their enthusiastic help, interesting discussions, and review of the maps and manuscript. |
