PREFACE 



with trees has varied less than might be supposed, 

 while the swamps remain practically unchanged. 



The swamps are evidently the basins of what 

 were once ponds or small lakes. These have become 

 filled with sediment or covered over with aquatic 

 growths of one kind and another which in time at- 

 tained sufficient thickness and stability to support, 

 first, the bulrushes and alders spreading out from the 

 shore, and, finally , forests of willows and water-ash 

 and maple. The tree-roots bound the whole together 

 and penetrated downward into the water beneath, 

 now steadily being filled up and confined to slowly 

 diminishing channels and underground basins, which 

 I believe are still in existence beneath many of our 

 swamps to an extent not generally suspected. 



I know of one quite extensive swamp in this 

 vicinity, drained at one end by a brook which for the 

 first part of its course is roofed over or bridged by 

 several feet of black loam, which breaks down here 

 and there for a few yards, and reveals the silent 

 course of the stream beneath. Although the water 



