SOILS OF ILLINOIS. 797 



abundant in the northern part of the region than the southern. Peat bogs 

 occur, however, south of the center of the State of Illinois. 



Many bogs are underlain by shell marl as well as by peat. The marl 

 is seldom sufficiently pure or abundant to be used in the manufacture of 

 lime. The marl beds are especially abundant on the south and east borders 

 of Lake Michigan. 



In many instances the bogs when drained, the peat being given time 

 to ripen and become warm, yield large crops of potatoes and other garden 

 truck. Wheat or other crops requiring mineral food in the ripening of 

 their grains can scarcely be expected to grow on such soil until it becomes 

 charged with earthy material by natural or artificial processes. 



