LITERATURE REVIEW*

    During the Jurassic and Cretaceous periods (190- 5 million years before present) this area experienced submersion, uplift, and extreme erosional activity. The growing Sierra Nevada range was the source the source of the sediment that made up the Franciscan formation. This included the greywacke, shales, and bedded cherts (Oakeshott, 1971 ). The Gulf of Mexico received nearly 15,000 feet of sediment during this period, indicative of a more humid environment. Along the Pacific coast of North America the early Cretaceous was warm (as much as 20 F, warmer than at present). Later Cretaceous floristics indicate a cooling and development of present day types of  flora and Fauna (Frakes, 1979).

    The early Cenozoic era appears to have been comparatively warm and humid Western California , from the San Joaquin Valley onto the continental shelf, experienced rapid sedimentation (Dodd, 1981). All positive land above sea level was eroded as the mountains and land masses  rose. San Luis Obispo was alternately inundated by and elevated above rising sea levels (Oakeshott, 1971 ).

*Dayton, E. S. 1984. Central coast serpentine weathering processes theory and field product identification Senior project, Library, California Polytechnic State University, San Luis Obispo p. 28.