This map database represents the integration of previously published and unpublished maps by several workers (see Sources of Data index map on Sheet 2 and the corresponding table below) and new geologic mapping and field checking by the authors with the previously published geologic map of San Mateo County (Brabb and
Pampeyan, 1983) and Santa Cruz County (Brabb, 1989, Brabb and others, 1997), and various sources in a small part of Santa Clara County. These new data are released
in digital form to provide an opportunity for regional planners, local, state, and federal agencies, teachers, consultants, and others interested in geologic data to have the new data long before a traditional paper map is published. The new data include a new depiction of Quaternary units in the San Francisco Bay plain
emphasizing depositional environment, important new observations between the San Andreas and Pilarcitos faults, and a new interpretation of structural and stratigraphic relationships of rock packages (Assemblages).
Additional Publication Details
USGS Numbered Series
Geology of the Palo Alto 30 x 60 minute quadrangle, California: a digital database