MAN'S MEANS OF OVERCOMING LOSS OF LAND 3?$ 



and bear evidence of constant struggle against wave destruction 

 (Fig. 242). 



Man's means of overcoming loss of land. Oceans like 

 rivers level down high places and build up low places. In 

 doing this they often cause serious inconvenience and loss to 

 man. The building up of sand bars dangerous to commerce 

 is no return to the farmer for fertile soil carried away by streams ; 

 neither is the piling up of soil on the ocean bottom any return 

 for a retreating shore line and loss of beach. In general, water 

 removes soil from places where it is useful and transfers it to 



FIG. 244. Mangroves in Florida. 



places where it is useless and even harmful. There are several 

 methods of lessening land erosion and loss of land. In Boston 

 harbor, for example, sea walls have been erected as a protection 

 against waves; and in places along the shores of the Mississippi 

 River willow trees have been planted as water breaks. Plants 

 are an excellent protection against waves. Where thick masses 

 of seaweed abound (Fig. 243), the rocks are less worn because 

 plants " give with " the waves and form an elastic covering 

 against which waves beat with little result. Along the New 



