194 Bibliography. 



not formed the soil which covers them^ is far too general in its terms. 

 And if the preceding statements are correct, we must believe that rocks 

 do sometimes affect the vegetation which covers them. We beUeve there 

 is some truth in the common opinion, that Umestone regions are more 

 prohfic of vegetation than any others. How very different is the Flora 

 of the trap ranges in the Connecticut valley from that of the primary 

 ranges of equal height on the sides of the valley ! How different the 

 oaks, maples, beeches, and hemlocks of the Hoosac mountain, from 

 the chestnut groves of the Taconnic ! Must not these differences be in 

 part imputed to the peculiarities of the soil derived from the rocks ? 



The author refers to the cultivation of the different sorts of grain on 

 all soils and in all the temperate regions of the globe, as proof that 

 rocks do not affect the vegetation above them. But some species of 

 plants, like some species of animals, are adapted by the Creator to 

 almost all climates ; and as man is one of them, we should expect a 

 beneficent Providence would give the same power to those cerealia, 

 which furnish him food. But let us attempt to cultivate the numerous 

 peculiar species found in particular localities in all places where grain 

 will grow, and we should fail in nine cases out of ten. Does this argu- 

 ment then from the cereals prove the point ? Would not the argument 

 from the other species referred to, be equally good on the other side ? 

 But we have neither time nor space to say all on this subject which we 

 could wish. 



The fourth principle of agricultural chemistry is that " all soils con- 

 tain enough of lime, alkali, and other inorganic elements, for any crop 

 grown on themy We are constrained to say that we could wish this 

 rule also were expressed in terms less general and sweeping. To 

 prove it, the author has taken a strong case, — the soil of a barren pine 

 plain. He supposes it formed of the drift of granite, which, upon an 

 average, contains seven and a half pounds of potash, and three eighths 

 of a pound of lime. An acre then, six inches deep, would contain 

 3626 pounds of lime, and 73311 pounds of potash. 



Granting the premises, the conclusion is irresistible. We will admit 

 that the soil of a pine plain may have been originally derived from the 

 disintegration or abrasion of granite. But let almost any soil of this 

 description be examined, and it will be found that the feldspar and 

 often most of the mica have nearly disappeared ; while little re- 

 mains but grains of quartz, which contain neither lime nor alkaU. 

 Thus nearly all of these ingredients may be removed from a soil ; and 

 such we apprehend to be the fact in respect to the soil of most barren, 

 sandy plains. Most feldspars, it is well known, decompose with great 

 readiness ; and in our opinion, it is from this mineral rather than the 

 mica, that plants derive their supply of lime and potash. 



