CHAPTER III 



YPES OF AQUAT 

 ENVIRONMENT 



o 



I. LAKES AND 

 PONDS 



UT of the atmosphere 

 comes our water supply 

 -the greatest of our 

 natural resources. It 

 falls on hill and dale, 

 and mostly descends 



into the soil. The ex- 

 cess off-flowing from the 



surface and outflowing from springs and seepage, forms 

 water masses of various sorts according to the topo- 

 graphy of the land surface. It forms lakes, streams or 

 marshes according as there occur basins, channels or 

 only plant accumulations influencing drainage. 



The largest of the bodies of water thus formed are 

 the lakes. Our continent is richly supplied with them, 

 but they are of very unequal distribution. The lake 

 regions in America as elsewhere are regions of compara- 

 tively recent geological disturbance. Lakes thickly 

 dot the peninsula of Florida, the part of our continent 

 most recently lifted from the sea. Over the northern 

 recently glaciated part of the continent they are 



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