88 



these points, it is so nearly exclusively used is evidence of the degree of its superiority 

 in other particulars. 



One point illustrated by the case of Douglas fir is so often overlooked as to be 

 worth emphasis. Not the least of the merits of Douglas fir, as a species, for piling use, 

 is its relative cheapness and the fact that its axailable supply on the Pacific coast is 

 greater than that of any other species whatever. Species have been repeatedly recom- 

 mended to the Committee and are advocated for use, like the cottonwood and the 

 alder, which, whate\er their technical merits, could not be found in accessible and 

 available stands of suitable form to supply by any possibility the current demand. 

 Conceivably there might be cases where Douglas fir or other preferred species might 



Fig. 32. (1) Dolphin pile from Richmond Municipal Pier, driven December, 1917, broken out July, 

 1920. Note large tubes of Bankia and smaller ones of Teredo navalis, and erosion by Lim- 

 noria at breaking level. Sphaeroma also present. Breaking zone exposed at low tide. 

 (2) Section of same pile, one foot above break. 



