288 ANALYSES OF SOILS. 



acid, and the growtli of the lower orders of vegetables, before the domesticated plants can 

 be cultivated with profit upon the soil formed of it. 



The rocks passing through the wheat district are arranged in terraces more or less distinct. 

 These are formed by the hard limestones and shales : the former are abrupt ; the latter 

 present a gradual ascent or descent. As terraces, therefore, the former are more distinct 

 than the latter, and present an approach to an elevated plain, while the shale terraces appear 

 in the form of rounded hills descending on all sides, so that their surfaces admit the rapid 

 disappearance of the water that falls upon them, by which they are liable to gully as well 

 as wash ; yet as slate is retentive of water, and its natural seams or joints are close and 

 almost impervious, its slojies and summits feel a drought less than the soils resting upon 

 hmestone. The latter are traversed by cracks or open joints, which suffer the water to 

 pass in streams, and thereby drain the surface to an injurious extent. In some instances 

 limestone hills are insulated, or cut entirely off from the succeeding shales, and, if naked, 

 or laid bare by denudation, would present on all sides a mural escarpment. It is easy to 

 understand that in such cases the water escapes, flows out from the escarpments, and 

 drains injuriously the whole tract insulated in the mode indicated above. 



An analysis of the soil reposing upon limestone gives less lime than that reposing upon 

 slate. I subjoin a few examples of analysis, which go to prove the truth of the position. 



Analyses of the soils resting upon the Pentamerus limestone, at Manlius square. 



SUBSOIL EIGHT INCHES BELOW THE SURFACE. 



Water of. absorption 1'48 



Organic matter 2*80 



Silicates 85-90 



Peroxide of iron and alumina 8 -57 



Carbonate of Hme 0'21 



Magnesia 0*05 



99-01 



This soil forms the first limestone terrace above (he village, towards Chittenango. 



SURFACE SOIL. 



Water of absorption 2-81 



Organic matter 4-59 



SiHcates - 84-64 



Peroxide of iron and alumina 7-28 



Carbonate of lime 0-50 



Magnesia 0-16 



_ 99-98 



The soil of this terrace is not supplied with a greater amount of drift than usual, and yet 

 the quantity of lime is less (ban upon (he Marccllus slate. 



