66 IPostelsia 



Iv 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 breach 

 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 su])p()rts. The soil therefore is large- 

 Iv of organic nature, of very dark color and of 

 fine consistency. A grouping of the vegetation 

 societies such as has loeen emj^loyed by various 

 American writers on lake strand vegetation 

 seems a])i)licable here, according to which we 

 consider first the front beach. 



a Front beach 

 Eqitisetum jJiiviatile society — This society ex- 

 hibits regular zonal distribution along the 

 beaches where there is no considerable propor- 

 tion of sand in the soil. It is therefore inter- 

 rupted by the stream inlets. The society ex- 

 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 



