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April 29, 2003 Job Number. LG03-103 Page 4 There are no wells on the subject property;therefore, no water quality samples were taken. VL GEOLOGY, SOILS, AND PERCOLATION TEST The surficial geology of the site is separated into many areas comprised of three types of geologic formations. The Mehrten Formation is the oldest on the subject property. It is described as andesitic conglomerate, sandstone, mudstone and lahars. The Mehrten Formation formed in the Miocene and Pliocene epochs of which the Miocene(oldest)began 24 million years ago. The Laguna Formation is the second oldest formation on the subject property. It is described as arkosic gravel, sand and silt with some inter-bedded volcanic detritus derived from the Mehrten Formation; moderately consolidated in contrast with weaker consolidation of younger deposits below the soil zone (Redding and Corning soils, deep variant). The Laguna Formation formed during the Pliocene epoch,which began approximately five million years ago. The Modesto Formation- Foothill is the most recently deposited formation found on the subject property. It is described as derived alluvial silt, clay and minor sand forming terraces, upper fans and following distributaries across lower fans; abundant volcanic detritus (Honcut, Wyman, Capay soils). The Modesto Formation-Foothill was formed during the Pleistocene epoch which began 1.6 million years ago.' The Riverbank in the San Joaquin Valley is predominantly arkosic alluvium while the Sacramento Valley contains more mafic igneous rock fragments' (Plate 6). Essentially, these formations are consolidated older alluvium. The surface and near surface soils located on the site are reported to be the Corning- Redding complex, Kaseberg loamy sand,Kaseberg fine sandy loam, Pardee cobbly loam, Redding ` gravelly complex and the Yellowlark gravelly loam(Plate 7).° Table 3 presents an excerpt of some selected engineering properties for soils located on the subject property. 'Marchand,D.E. and Bartow,J.A-, 1979. Preliminary Geologic Map Of Cenozoic Deposits Of The Bellotti Quadrangle, California;U.S. Geologic Survey Open File Report 79.664, scale 1:62,500. 3 Helley,E.J.,and Harwood,D.S., 1985. Geologic map of the Cenozoic Deposits of the Sacramento tr Valley and Sierran Foothills,California;U.S. Geologic Survey Miscellaneous Field Studies Map,MF-1790,scale 1:62,500. t. ° USDA Soil Conservation Service, 1992, Soil Survey of San Joaquin County,California, Sheet 7. 6. pFFS 4 6. O