On back: "SAN FRANCISCO-OAKLAND BAY BRIDGE; Walter G. Swanson; 500 Sansome St. - GA rfield 1415. File 900.11 B-12/BD. Aerial view showing two 40-Ton Guy Derricks on top of Concrete Shaft of Pier W-4, the Concrete Center Anchorage, which will erect the huge steel A-Frame to which the cables of the twin suspension spans will be anchored. At the south side of the Pier may be seen the barge load of steel which will form the bottom section of the A-Frame. According to Chief Engineer C. H. Purcell, the height of the Concrete Center Anchorage from water level to top of concrete is 235.18 feet."
