50 GEOLOGY OF ILLINOIS. 



by tbe growth of timber. TVhere tbis is mainly composed of two or 

 tbree varieties of oak and bickory, the soil is thin and poor, and will 

 require frequent applications of manure or otber fertilizers to keep it up 

 to the ordinary standard of productiveness for western lands. But 

 where the timber growth is largely interspersed with elm, black walnut, 

 linden, wild cherry, persimmon, honey locust, etc., the soil is good, and 

 will rank favorably with the best prairie lands in its productive qualities. 

 A large portion of the timbered land in the county is of this quality, 

 and when cleared and brought under cultis'ation, it produces nearly or 

 quite as well as the best prairie land. 



I am indebted to Mr. J. B. Wolf, of Olney, former county surveyor, 

 for much valuable information, and for personal attention and assist- 

 ance while at work in the county. 



