U. S. B. F.— Doc. 920. 



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FIG. 24.— SECTION OF SHORE LINE 10 MILES NORTH OF SILETZ BAY. 



The rocks paralleling the coast are densely covered with the large sea mussel, Mytilus cali- 

 fonrianus. This region is an isolated one. 



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FIG. 25. — PORTION OF SURFACE OF ONE OF THE ROCKS IN FIGURE 24. 

 Masses of the large sea mussel are shown in the upper half of this picture. 



