17 x 22" 15 minute sheet is deceiving in its simplicity. Looks like any other, but has amazing period details relating to the early steamboat and rail system servicing Sonoma and Napa counties from San Francisco . Mare Island, Embarcadero, Wingo, Carneros at cuttings wharf are all evident and documented . Sears Point and the NWPRR and Sonoma Valley spur both in good operating order. riparian and land use data in icon form.