OGLE COUNTY. 121 



No(7.s- and their products. The dark-colored loams are underlaid by a 

 light-colored, clayey or gravelly sub-soil. The loam is largely composed 

 of vegetable elements. If not made up of, it is at least greatly enriched 

 by the successive growth and decay, for ages, of our common prairie 

 grasses. This is the soil of our prairies. The timber soils are the usual 

 clayey deposits of the oak ridges, underlaid by a close, compact, yellow 

 sub-soil. Hungry, sandy soils are seldom met with. Leachy, loamy, 

 fat soils, well adapted for the best farming lauds, cover most of the 

 county. The soils in this portion of the State are composed of silica, or 

 the earth of flints ; alumina, or fine impalpable clays ; carbonate of 

 lime, or calcareous materials, making marly soils ; and various other 

 materials, such as the oxyd of iron, organic matter, and the b'ke. The 

 two first are the basis of all our soils. The" last gives them fertility. 

 y<> soil is composed of a single one of these elements ; but the mixture 

 or chemical combination of all these, and sometimes many other ele- 

 ments, exist in the same soil, making clay soils, clay loams, loamy 

 .soils, sandy soils, vegetable molds, marly clays or sands, and many 

 other kinds of soils, well known to agricultural chemistry. 



I think the general proposition is true, that where large tracts of coun- 

 try are underlaid by the same or closely related geological formations, 

 the soils will have some resemblance to those formations. They are un- 

 doubtedly, in part, derived from them ; and in many cases in this part 

 of the State, as I have already intimated, the soils and sub-soils seem 

 to show their origin from these subjacent rocks. But this remark must 

 be received with considerable allowance. The transporting, sorting, 

 and sifting agency of water, the ice action of glaciers and icebergs, and 

 the evidences that other geological forces have been at work all over 

 this region, leads us to greatly modify the statement just made, and to 

 believe that our soils are, in part at least, derived from many sources 

 some of them remote from their present localities. The same is true, I 

 think, of the sub-soils, and finer mateiials of the drift. These, originally 

 perhaps, were all alike : but chemical and atmospheric agencies and 

 the growth of vegetation changed the surface clays into rich fat soils ; 

 the sub-soils received less of these influences, but still felt them, and 

 were further changed by the percolating, saturating surface waters ; but 

 the deep lying clay and saudbeds received no change from these agen- 

 cies. Even the acids of the air could not penetrate to them, and they 

 remain unchanged. 



Ogle county shows more evidences of a transported soil than western 

 Stephenson or Carroll county. 



Geology, engaged in investigating these phenomena, is thus the hand- 

 maiden of agriculture, and ought to be encouraged and studied by the 

 farmer. He should not be slow to learn that all branches of human 



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