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And to this illustration of a fact, which may be proved, 

 I beUeve, by observation in every country of the globe, Sir 

 Charles Lyell adds a sentence, from which I am sure you 

 will at once draw an important, practical lesson. "On 

 reaching Texas, all these different classes are at fault, be- 

 cause the cretaceous strata in that country consist of a hard, 

 compact, siliceous limestone, which defies the decomposing 

 action of the atmosphere, and forms table lands of bare rock, 

 entirely unlike the marls, clay and sand, of the same age, 

 in Alabama." 



The tillers of the red land, of the pine barrens, of the 

 marshy prairies, and of the sea island swamps, are equally 

 at a loss when they migrate to a country of which the soils 

 and surface differ from all they have left. And how is 

 this ? Because they have no familiarity with those general 

 principles of chemical science on which all culture on all 

 soils depends — because, if they wish to continue the same 

 kind of tillage, and on soils similar to those they have left, 

 they have not such a knowledge of the general principles of 

 Geology as would enable them at once to say, to this or to 

 that country, I must go, for there alone am I likely to find 

 them. 



In my own country, I have been accustomed to press 

 upon the agricultural community the importance of such 

 geological knowledge to them, because of the numerous 

 colonies we possess in all parts of the world, and because of 

 the swarms of emigrants we yearly send off to subdue and 

 people them.* But to you whom I now address, who 

 already occupy, or in connection with kindred blood are 

 destined to subdue and people, nearly half a world — how 

 much more important must such knowledge be! Your 

 westward movement will continue for many generations, 



* See the Author's Elements of Agricultural Chemistry and Geology, Fifth 

 Edition, p. 616. 



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