CLASSES OF SOIL. 19 



these preponderate, ranging from clay loams to sandy 

 loams. They differ, as a rule, from fertile clays in 

 possessing less organic matter, iron, and alumina, and 

 more phosphoric acid, carbonic acid, and silica. 



Marls are a mixture of clay and lime, and vary as 

 above, as one or the other ingredient is in excess. 



Calcareous soils are usually thin, and are composed 

 of the debris of the underlying stratum, with a greater 

 or less amount of organic matter. 



With all these soils, and their modifications, the 

 forester and agriculturist have to do ; there is, how- 

 ever, this essential difference, the latter has greater 

 command of it than the former. The latter may 

 choose the soil to the plant, or the plant to the soil, 

 but the former can only adapt the trees to the soil. 

 Herein is a great difference. The agriculturist, too, 

 as long as the subsoil is porous, naturally or artificially, 

 thinks or concerns himself little about it. He deals 

 with the surface, which is his storehouse. The 

 forester, on the other hand, must concern himself 

 with both, and especially with the subsoil. It will 

 not be sufficient to examine the surface and then 

 decide upon the tree to plant ; he must seek lower, 

 and ascertain what the trees will have to draw upon 

 in years to come. As an instance of this, and to show 

 the importance of it, we may mention a case in which 

 we were personally concerned. On inquiring into 

 the death of an ornamental tree, we found the top 

 soil to the depth of about eighteen inches perfectly 

 dry sand, not sand in the true sense of the word, but 

 a dry fine soil like dust ; immediately below this, and 

 with no blend, the soil was a yellow clay, wet and 



