PLATE 1 



Fig. 1. Pile from Associated Oil Co. wharf, Port Costa; driven 

 with bark on, presumably in 1910, removed in 1921. Borers at- 

 tacked where bark protection was damaged. 



Fig. 2. Concrete protected pile, Koetitz type, showing typical 

 rusting crack above high tide level. From bulkhead between 

 Piers 28 and 30, San Francisco; driven 1909. 



