240 GEOLOGY OF ILLINOIS. 



ones ; and it is through the beds formed along the slopes of the valley that 

 the water probably finds means to escape to a higher level. It is only the top- 

 most layers of the boulder clay and those of the overlying clays of the Loess 

 which prevent its escape everywhere to the surface. 



Many persons have been inclined to suppose this to be " mineral water," or 

 " poisonous," because where the surplus overflow has been allowed to run 

 through orchards, it has killed the trees. But this was only in consequence of 

 their being suffocated, by the water preventing the access of air to their roots. 

 Care should be taken, in sinking these wells, to select points where the sur- 

 plus water can escape directly to the channels of natural drainage. 



The area within which these wells have been successfully sunk is about fif- 

 teen miles from north to south, and about thirty-seven from^east to west, in- 

 cluding a small part of Ford county, as indicated upon the map. At many 

 points outside of this area, the water comes within a few feet of the surface, so 

 as to be pumped out with the utmost ease. 



For information concerning this county, I am especially indebted to Edward 

 Rumley, Esq., of Onarga, and H. S. Wing, Esq., of Kankakee City. 



