19thcentury aerialphotography antiquities archaeology asia barnstablecounty belgic belize bronzeage california capecod china commerce economicconditions england essex excavations(archaeology) governmentpolicy history kites massachusetts mayas neolithicperiod pictorialworks pottery prehistoric prehistoricantiquities prehistoricsaltminesandmining railroads roman salt saltmarshes saltminesandmining sanfranciscobay sanfranciscobayarea seasalt seawater soc003000 socialscience socialsciences socialstructure zhongbasite