234 GEOLOGY OF ILLINOIS. 



gives no opportunity of determining the exact outlines of the group ; but it is 

 evident that the Coal Measures occupy but a narrow strip of the western side 

 of range 9, and the Niagara limestone a probably still narrower one on the 

 east side of range 10. 



A boring in Otto township, five and a half miles south of Kankakee City, 

 and eighty rods west of the railroad, started above the top of the highest beds 

 seen on the Iroquois ; and the following section of it was reported to me by 

 Mr. H. A. Williamson, of Kankakee City, who superintended the boring, 

 after it had reached the depth of two hundred and eighty-seven feet : 



FEET. 



1. Gravel and clay 47 



2. Clouded solid stone " not limestone " 388 



3. Shale, with limestone bands and flints 75 



4. Impure limestone, slacked but little 40 



6. Nearly black, slightly gritty shales 15 



6. Shale, with limestone bands and " flints " 83 



7. Pyrite ' 1 



8. White shaly limestone 1 



Total 651 



The three hundred and eighty-eight feet of "clouded solid stone," undoubt- 

 edly includes all the limestones, pure and impure, of the Niagara group. The 

 impression that it was " not limestone," arose from the fact that certain speci- 

 mens, when burned, did not slack. No. 3, with its " flints," may possibly be- 

 long to the Niagara; but I am more inclined to account it the top of the Cin- 

 cinnati group, and to suppose that the "flints" of both it and No. 6, are merely 

 thin layers of compact clinking limestone, sometimes pyritous, such as .are fre- 

 quently called flints by borers and quarrymen, although they contain no 

 noticeable amount of silica. Nos. 7 and 8 apparently represent the top of the 

 Trenton limestone. If that bed has here the thickness of two hundred feet, 

 which is usual in this part of the State, the top of the water-bearing St. Peters 

 sandstone would be reached at eight hundred and fifty-one feet, about one hun- 

 dred feet nearer the surface than it would be, if the dip observed in Grundy 

 and Will counties was continued to this place. 



Economical Geology. 



The local supply of all especially valuable minerals is small ; and the county 

 must rely for wealth, chiefly upon its agricultural and manufacturing capaci- 

 ties. Aside from the sandy ridges of its river bottoms, its soil is fertile and 

 already produces large crops. But much of the surface is yet uncultivated, 

 and, as elsewhere in fertile countries, the abundance of rich land leads to waste- 

 ful farming, which, before many years, must inevitably lead to the production 



