8<, 



1. If a hill is surroTiuded l);.- other hills, a mesopliytic flora raa-j 

 often lie prodiioed. A hill protected hy higher hills nay have a 

 mesophytic flora to tlie top. 



In a V-shaped valley the flora will prohahly he raesophytic 

 being protected from excessive heat, wind and cold. Wliile the 

 slope tends to make the soil dry, this will he counteracted hy the 

 absence of strong lifjlit. Vfiien erosion changes a V-shaped valley 

 to a U-shaped one, one side will have a mesophytif; flora, the other 

 side protecting it just as hills surrounding it may protect .another 

 hill. Two factors tend to produce a mesophytic flora on hills. 



1. The physiographic changes of the hills. 



2. The accumulation of humis. 



Tius is beaut ifull:' shown in the Wlaite Ilountains wh'-'re we 

 have a raesophytic flora before a base level is teached. On the other 

 hand, on the seashore or desert, we may have base level without a 

 mesophytic flora. 



II. A hill exposed to ocean action must remain xerophytic as long as 

 the ocean remains, so will have a xerophytic flora in a mesophytic 

 climate. There may be a mesophytic flora if the ocean has encroached 

 on the land "bringing areas formerly removed from water action to 

 the coast. In order to have a mesophytic forest, there must be a 

 great amount of atmospheric moisture. 



