II SOILS ir 



elapsed during which the natural forces we have been 



considering have been at work, we cannot understand how 



the soil could possibly have been made by the slow wearing 



away of granite and other hard rocks. But the more we The marvels 



study these great questions, the more marvellous does Nature ^^ Nature. 



appear to us to be. 



Local Soils and Transported Soils.— As we have 

 seen, the soil may be carried long distances by the agency of 

 water and wind, and thus the soil may be found to be very 

 different in its character from that made from rocks in the 

 neighbourhood. When this occurs the soil is said to be 

 transported. And when the soil formed in a place is not 

 carried away but remains where it was made, it is said to 

 be locals or indigenous^ or sedentary —yN\\\Q\\ really means 

 that the soil is, so to speak, home-made, and not imported 

 from other places. 



Surface Soil and Sub-soil.— If a deep hole be dug in 

 the land, it will usually be found that at some distance below 

 the surface the character of the soil becomes altered. On 

 the top the soil is darker in colour and much easier to dig, surface soil. 

 because it is looser ; this is called the surface soil, and its 

 darker colour is caused by the decayed leaves and roots and 

 stems of plants it contains. The lighter and closer soil at Sub-soil. 

 the bottom of the hole is called the sub-soil^ and it varies 

 considerably in character. It may be made up of sand, or 

 of gravel or clay, or it may be like the surface soil. The 

 sub-soil may be a local soil, and the surface soil a trans- 

 ported one, or vice vers-d, and when this happens they will 

 usually be very different in their nature. The surface soil 

 varies in thickness according to its position and surround- 

 ing influences. In forests and highly cultivated lands, it 

 is usually deep, but on steep hill sides and in dry places, it 



is shallow. Earthworms 



Earthworms. — Darwin, the great naturalist, has shown f^ '" ^^^ 



^ ° ' formation 



that earthworms exert a wonderful influence in the forma- ofsoil. 



