688 GEOLOGY OP OHIO. 



Attention is called to one or two other points in connection with these 

 analysis. >■ 



(a.) The marked disparity in the amounts of phosphoric acid which soil 

 and subsoil respectively contain is doubtless due, in part at least, to the 

 abstraction of this substance from the surface by the crops that have been 

 raised here. Of all the constituents of the soil, this certainly is the one 

 that according to theory should be most reduced by the prevalent system 

 of tillage. There is still left in the soil a large aggregate of this sub- 

 stance, it is true, but it is to be remembered that plants can not go on 

 growing until all is removed. To make agriculture profitable, these min- 

 eral elements of plants must not only be present in the soil, but must be 

 every where diffused, so that each rootlet of each plant shall be able to 

 secure its share. It is altogether probable that the change of one-tenth 

 of one per cent, is enough to make the difference between sterility and 

 generous harvests. 



(6.) The chief notable lack in these analyses is in the soluble forms of 

 potash and soda, and in carbonate of lime. These are the very sub- 

 stances that would be furnished by the application of ashes and lime- 

 waste from the lime-kilns of the country. Ten thousand cords of wood 

 are burned every year at Springfield in the manufacture of lime ; but 

 until within the last two or three y«ar3 not one bushel in a thousand of 

 the ashes produced has ever been restored to the land. At Yellow 

 Springs and at Clifton — both of which are surrounded with clay soils of 

 this general description, and where large quantities of lime are annually 

 burned — the same thing is true, though lime and ashes may be had for 

 the carting. 



Two other analyses are added, in this division, of soils of better grade 

 than that already reported upon. No. 7 is from the farm of John How- 

 ell, Esq. (Mad River township, Clarke county), and No. 9 from the land of 

 John Snyder, Esq., of Springfield. Both of these analyses represent the 

 average yellow clays of this region. No. 8 represents the composition of 

 the subsoil of No. 7; but there is some reason to distrust the result! 

 shown in this analysis. In the comparatively large proportion of or- 

 ganic matter it can hardly represent the average. 



4. One variety still remains to be described, viz., the soil of the 

 black uplands of this region, including the upland prairies that are 

 occasionally met. This soil might with a measure of propriety be dis- 

 tributed among the two last named divisions, as it has differed in fortune 

 from one or other of them in but a single particular. By the accidents 

 of the later geological history of the country, these common deposits of 

 bowlder clay and stratified sand and gravel have been left generally in 



