AGRICULTirrvAL MUSEUM 311 



c'srcu?!! stances cause the soil to be of a firmer and more 

 retentive quality, as is required by reason of its elevated 

 and uneven surface. 



j^nothcr trait which distinguishes this from the region 

 wc have denominated alluvial, is easily observable > I 

 mean the size of the forest trees. In the alluvial regi- 

 on, more especially in the first division of the alluvial re- 

 gion,, the soil is looser to a greater depth than in the hil- 

 ly region, and therefore the roots of the trees can pene- 

 tiate more easily, and to a much greater depth than in 

 the hilly region, where the first or upper strata, which by 

 the laws of gravitation are generally the lightest, have in 

 the course of ages been worn away with the rains and 

 the torrents, and brought to the surface a soil more im- 

 penetrable, especially at a small depth under ground. 

 Besides, the substratum in the hilly region, and particular- 

 ly in the mountainous region, of which we shall speak 

 in the sequel, is frequently rock of various kinds, chief- 

 ly sand stone, lime stone, marble, schisus, and granite. 

 These rocks in the hilly region are found but a few feet 

 underground, and frequently project above the surface. 

 The trees, therefore, meeting with these obstacles, are 

 not in general so large as m the alluvial region. In the 

 vallies of this region, however, there frequently is found 

 a soil of sufficient depth to admit of the growth of the 

 largesttrees. 1 donor wish to be understood, that the 

 fertility of the soil in these regions, differs in proportion 

 to the size of the forest trees. — No, it is a remarkable 

 fact, that many tracts of couRtry in the hilly region, that; 

 are covered with trees of slender and inferior dimensi- 

 ons to the trees generally found in the alluvial region, 

 are extremely fertile in small grain ; and in Virginia and 

 Maryland, grow good Indian corn, though the stalk is 

 not generally so large as in the alluvial region. The rea- 

 son is that the soil is firmer, more impermeable and re- 

 tentive, and yet not delicient in natural riches. The 

 fijirface to a sufficient depth for the growth of grain, may, 

 by being suiBcientJj pulverised by cultivation, be ren- 

 dered completely adapted to the growth of grains, grass- 



