No. 422.] PHYLLOSPADIX AS A BEACH-BUILDER IO9 
The result of the accumulations, then, is that the water is 
made shallower, so that, though the pounding of the heavy 
seas upon the shore is lessened, the waves still race in over 
the shallows and carry up the smaller particles to deposit them 
on the beach. At the same time, even though the littoral 
drift be not held permanently by the eelgrass, yet the time 
required for it to pass the place, and hence its chance of 
contributing to the beach, is increased. 
Shoaler and shoaler grows the water, the shore line advan- 
cing as a low beach, and finally, — the littoral current being 
deflected seaward and the wave deposition continuing, — the 
terrace that was is overlaid by a sand-flat. 
That the long, hemp-like fibers of eelgrass lend coherence to 
the mass of sand and stones in which they are imbedded is 
attested by the fact that where, as above, we find a clump 
of eelgrass half-buried in the sand, the level of sand within the 
clump is often several inches above that of the surrounding 
beach. 
In closing, and to recapitulate, it seems probable that the 
spreading over a terrace of such a plant as Phyllospadix must 
tend, first, to protect the rocks from erosion and attrition ; 
second, to help, by trapping the shore-drift, to raise the terrace 
so as to form a beach, or a sublittoral sand-flat ; and last, by 
binding together its materials, to render the foundation of the 
beach, once formed, more coherent and stable. 
UNIVERSITY OF CALIFORNIA, BERKELEY, (CAL, 
