180 GEOLOGY OF ILLINOIS. 



trict, there is but one boring which affords an artificial section of the beds 

 down to the base of this formation. This one is that made by Voris & Co., on 

 the bottom lands on the Tazewell county side of the Illinois river, and directly 

 opposite the city of Pepria. The first bed of the Coal Measures which is met 

 with in the boring, is about forty feet below the lower coal seam which is 

 worked in this section, No. 4 of the Illinois river section, as given by Prof. 

 Worthen. The following is a section of the first four hundred and fifty-nine 

 feet of the boring. Below that depth, the records kept by Messrs. Voris & 

 Co. were not complete, as to the thickness and material of all the different beds : 



FEET. FEET. 



1. Alluvial soil of river bottom , 4 



2. Sand 4 



3. Gravel (boulder drift) 20 



4. Clay shale 59 



5. Bituminous slate 3 



6. Fireclay 15 



7. Clay shale 15 



120 



8. Coal 4 



9. Clay shale 34 



10. Sandy and argill. shale (very hard) 34 



1 1. Sandstone 4 



12. Nodular, argill. limestone 6 



13. Compact, fine grained sandstone 5 



14. Hard, dark blue, sandy shale 25 



15. Coal 3 



235 



16. Sandy and argill. shale 25 



17. Bituminous shale, with thin bands of limestone 57 



18. "Cherty rock" 44 



19. Hard, silicious rock, mainly chert possibly chert and limestone intermixed . 33 



20. Fine grained sandstone 65 



459 



As nearly as the limits of the formations can be made out from this section, 

 I think that at least that portion between the base of the Alluvium and Drift, 

 and the bituminous shale and limestone No. 17 of the section, may be referred 

 to the Coal Measures. The remainder is Devonian, with perhaps some of the 

 upper beds Lower Carboniferous. The exact equivalents of the two beds of 

 coal passed through, may perhaps not be stated with certainty; the lower one, 

 however, is probably No. 1 of the Illinois river section. The greatest depth 

 reached in the boring was seven hundred and seventy-four feet, and the lowest 

 rock was a gray, porous limestone, the fragments of which, brought up by the 

 instruments, were exactly similar in appearance to some of the upper limestones 

 of the Niagara group, exposed in the northern part of the State, with which 

 formation this bed may doubtless be properly identified. 



