56 FARM DEVELOPMENT 



covered with groves of large trees. In the dry season 

 of 1894, the forest fires in places burned away forests in 

 the Great Lakes region, and even burned the mosses 

 and other vegetable materials, so that in some bowlder 

 soils one could see a foot or more down among the 

 bowlders. Thus was destroyed in a day a forest-bear- 

 ing soil which nature had required many centuries to 

 build. 



In some places vast tracts of land are covered with 

 sand, and furnish most difficult conditions for vegeta- 

 tion to start. In case these sandy soils lie many 

 feet above the supply of underground water and are so 

 dry that plants cannot get their roots down to the 

 moisture, nature covers them with vegetation only with 

 great difficulty. The minute lichens, or even large plants, 

 have trouble here in securing a foothold, for the sand is 

 shifted about by the wind, and, in some cases, the shift- 

 ing is so regular that plants can never be produced by 

 nature in quantity to bind the sand into a soil and thus 

 cover it with a blanket of vegetation for protection. 

 Where the moisture is near the surface of the sand, as 

 where water seeps out through a hillside, or where clay 

 lies near the surface, or where the sand is near water 

 which passes back under it, plants can get their roots 

 into this water and more quickly fill the soil with de- 

 caying plant roots and other materials to protect them 

 from the winds. Thus some sandy lands lying high and 

 dry, shift before the wind and are never covered with 

 vegetation, while others that seem equally sandy at the 

 surface, but contain water within reach, are covered with 

 a luxuriant growth. 



Soil formation on moorlands. Where water lies on 

 flat areas and keeps roots and stems of mosses and 

 other plants from decaying, there is formed a layer 

 of partially decayed vegetable matter, called peat, 

 or peaty soils. The strangest place, however, for soil 



