This polygon shapefile describes the general distribution and identity of geologic materials in Sonoma County, Calfornia, from 1970 unitl 1980. Although based on the units distinguished on geologic maps, it is not itself a geologic map because it does not address geologic structure or the stratigraphic organization of the map units in a systematic way. The materials database delineates map units that differ in physical properties, although the differences between many of the units may be small, depending on the properties of interest for any particular application. The materials units are categorized in the database by general age and lithology, by the geologic units that they represent, and by the map labels used in the compilation sources, which permit direct correlation with the unit descriptions of those sources. This layer can be used for watershed analysis and planning in the Russian River region of California. Circuit Rider Productions and National Oceanic and Atmospheric Administration (2002). Summary Distribution of Slides and Earth Flows: Sonoma County, California, 1970-1999. Circuit Rider Productions. Available at: http://purl.stanford.edu/dd891cb7254 This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.