I 



CLAflSnPICATION OF SOILS. St 



nearly all originally formed from this rock. Many of 

 these are very poor; but there are some sandstones 

 which make most excellent soils, as rich as any that 

 are cultivated. In particular cases they contain so 

 much lime as to be nearly marls, and then form very 

 fertile soils. Verj- many sandstones crumble away 

 quite readily, some showing the action of the atmo- 

 sphere almost immediately upon exposure. For this 

 reason the soils are ordinarily of good depth. 



2. Limestone is also common, and there are few 

 places where a teacher can not find some to exhibit to 

 his scholars. It is found of all colors from white to 

 black, and makes a ?reat variety of soils. As a ge- 

 tter:- ood, and < t' bearuMT 

 Vers I n'ismmli im among 

 the limestones as to ease ot decomposition. Many oi 

 them form a deep soil v. rv <....n, Init there are some of 

 the blue mountain lii which decompose witk 

 exceeding slowness. </ii iiu-.sf the soil is thin, bat 

 usually of rather good quality, espcciallv for partures. 



3. Clay is the principal ingr- i roofiog sllilif^ 

 in school slates, and in what .< .i shalu. Be- 

 side this, as is well known, it exist.s in large beds, 

 from which are made pii>es, bricks, tiles, etc. etc 

 Whenever it occurs largely in soils, tber arc flltf^ 

 tenacious, and nearly inii)er\'ious to oioisttire. ii 

 cmiBequence water remaias on the suHaee, and aoakes 

 them wet, difllicuh to plough, and h;r ! . [n 

 any way. They are, however, usual , , 

 and by proper skill may be made nitwt valuaWe. 



Soine writers haveclawifjed soils, according as they 

 contained more or less of one of these. First would 

 be a sand, then a sandy loam, then a clay loam, a stiff 

 clay, and fmully a brick or pipe day, the last bein« 

 too stiff for cultivation. Soils in which lime existed 

 largely, would l>e called calcareous. Where there 

 was more than 2() to 25 per cent, it would be a marl. 



