CHAPTER LII. 



STRUGGLE FOR OCCUPATION OF LAND. 



681. Retention of made soil. — In the struggle of plants for 

 existence, there are a number of species which stand ready to 

 rush in where new opportunities present themselves by changed 

 conditions, or by newly made soil. The permanent drainage of 

 ponds or marshes brings changed conditions, and the flora there 



Fig. 476. 

 Made soil at mouth of stream, being overgrown by plants. Ithaca, N. Y. 



undergoes remarkable transformations. The deposits of the 

 washings of streams in protected places along the shores, or at 

 their mouths, where deltas or lateral plateaus are made by the 

 accumulations of soil scoured off the banks of the stream, or 

 washed off the fields during rains, make new ground. With such 

 banks of newly made ground are deposited seeds carried along 

 with the soil, or dropped there by the wind, by birds, or other 

 agencies of seed distribution. 



682. Figure 476 is from a photograph taken at the mouth of 

 one of the streams emptying into Cayuga Lake. At the left is 



374 



