KINDS OF SOILS. 145 



The surface of tlie country when covered with drift is 

 often or usually irregular and hilly, the hills themselves 

 being conical heaps or long lidges of mingled sand, gravel, 

 and boulders, the transported mass having often a great 

 depth. These hills or ridges are parts of the vast trains 

 of material left by the melting of preadamite glaciers or 

 icebergs, and have their precise counterpart in the moralneA 

 of the Swiss Alps. Drift is accordingly not confined to the 

 valleys, but the northern slopes of mountains or hills, whose 

 basis is unbroken rock, are strewn to the summit with it, 

 and immense blocks of transported stone are seen upon 

 the very tops of the Catskills and of the "White and 

 Green Mountains. 



Drift soils are for these reasons often made Tip of the 

 most diverse materials, including all the kinds of rock and 

 rock-dust that are to be found, or have existed for one or 

 several scores of miles to the northward. Of these often 

 only the harder granitic or silicious rocks remain in con- 

 siderable fragments, the softer rocks having been com- 

 pletely ground to powder. 



Towards the southern limit of the Drift Region the 

 drift itself consists of fine materials which were carried 

 on by the Avaters from the melting glaciers, while the 

 heavier boulders were left further north. Here, too, may 

 often be observed a partial stratification of the transported 

 materials as the result of their deposition from moving 

 water. The great belts of yellow and red sand that 

 stretch across New Jersey on its southeastern face, and 

 the sands of Long Island, are these finer portions of the 

 drift. Farther to the north, many large areas of sand 

 may, perhaps, prove on careful examination to mark the 

 southern limit of some ancient local glacier. 



Alluvial Soils consist of worn and rounded materials 

 which have been transported by the agency of rumiing 

 water (rivers and tides). Since small and light particles 

 are more readily sustained in a current of water thaa 



