SOIL FORMATION: ROCK DISINTEGRATION. 321 



marginal zone 

 where they first 

 entered, and the 

 ground is some- 

 what more eleva- 

 ted, attained a 

 much greater 

 height. 



486. Fall of 

 the trees on the 

 marginal zone 

 when the wind jr 

 break was re- |" 

 moved. T h e s e 



ft 



large trees of the | 

 marginal zone, J 

 though they were w 

 rooted to a great Jl 

 extent in loose \ - 

 soil, nevertheless jf 

 were protected 

 from winds by the < 

 forests on the sur- | 

 rounding hills. g. 

 When, however, 8* 

 these hills on three 

 sides were cleared 

 for cultivation the 

 wind had full 

 sweep, and many 

 of the large trees 

 were uprooted by 

 the force of the 

 gales. This view 

 is supported by the 

 fact that the west- 



