40 ECONOMICAL GEOLOGY. 



No. Ft. 



21. Fire clay 8 



22. Light shale 27 



23. Light hard limestone 9 



24. Fire clay and slate ' 1 



25. Coal : 8 



26. Fire clay and shale (dump) 20 



Total depth 401 



The boring made at Sorento previous to sinking the shaft 

 was carried to the depth of 612 feet without finding any other 

 seam of coal of practical value. The following beds were passed 

 through by the drill below the bottom of the shaft, as pub- 

 lished in the Greenville Sun: 



No. Ft. 1 



211 

 Shaft 401 



Total depth 612 



Although SorentO and Smithboro are but a few miles apart 

 there is a marked change in the character of the beds encount- 

 ered in the two shafts at these points. At Smithboro three 

 seams of coal were found in a depth of 537% feet while at 

 Sorento a single seam only was encountered in a depth of 612 

 feet. Such sudden changes in the character of the strata are 

 not of common occurrence in the Illinois coal field, though they 

 have been rarely encountered at other localities. 



Three coal shafts were commenced without a preliminary bor- 

 ing in Marion county, and all have been prosecuted to a suc- 

 cessful issue; one at Kinmundy, and the others at Odin and 

 Salem respectively. The shaft at Kinmundy, although the 

 deepest of the three, was the first completed, reaching the hori- 

 zon of coal No. 6 at the depth of 869 feet. The seam at this 

 point was found to be divided by a parting of shale and lime- 

 stone about seven feet in thickness, the upper division of the 



