66 Postelsia 
ly built up of sand and has a width of many 
meters (15-50 meters). Along the places where 
there are no natural drainage courses like those 
mentioned above, the building up of the beach 
has been more uniform and gradual and is 
formed by loam deposits carried down from the 
surrounding slopes by the washings of countless 
rains and also by decay of the vegetation that 
the beach supports. The soil therefore is large- 
ly of organic nature, of very dark color and of 
fine consistency. A grouping of the vegetation 
societies such as has been employed by various 
American writers on lake strand vegetation 
seems applicable here, according to which we 
consider first the front beach. 
a” “BPront beach 
Equisetum fluviatile society—This society ex- 
hibits regular zonal distribution along the 
beaches where there is no considerable propor- 
fion of sand /in the soil. "Ws thereforesmnner. 
rupted by the stream) inlets: “Phe society tex 
tends even out into the water but since it seems 
to attain its typical development just above the 
water line, it is classed as a part of the beach 
