U ECONOMICAL GEOLOGY. 



be found in that portion of the State of sufficient thickness to be of 

 practical value. 



DANVILLE BOEING. 



Ft. In. 



No. 1. CoalNo.7 



No. 2. Shale 



No. 3. Coal (lower division of No. 7) > 6 



No. 4. Blue and gray shale 1~ 11 



No. 5. Blackshale 1 H 



No. 6. Coal No. 6 (Grape creek) 2 11 



No. 7. Fire-clay 2 7 



No. 8. Limestone and shale <> 5 



No. 9. Sandy shales 16 5 



No. 10. Grayshale $2 10 



No. 11. Black shale 



No. 12. Dark gray shale 16 2 



No. 13. Sandstone and shale 14 4 



No. 14. CoalNo.4 1 6 



No. 15. Shale 9 4 



No. 16. CoalNo.3 8 



No. 17. Grayshale 1 6 



No. 18. Variegated shales, bottom black 23 



No. 19. CoalNo. 2 4 1 



No. 20. Shale and limestone 3 



No. 21. Coal upper division of No. 1 9J6 



No. 22. Blackshalo 3 



No. 23. Coal lower division of No. 1 1 9 



No. 24. Shale and sandstone... ..66 10 



Total 286 5 



This boring has demonstrated that coal No. 2 may be found in 

 this portion of the State with a more than average thickness of fou 

 feet, and the superior quality of the coal wnich it affords will stim- 

 ulate those largely interested in coal mining operations to carry their 

 shafts down to this horizon, even where the thicker seams above 

 are well developed. The Ellsworth Coal Company are entitled to 

 the credit of making the first effort to ascertain what could be found 

 on the eastern borders of the Illinois coal field below the horizon of 

 coal No. 6. 



On the western border of the coal field in nearly the same lati- 

 tude, a shaft was recently sunk through the lower portion of the 

 Coal Measures, but developing no coal that was more than thirty 

 inches in thickness. For the following details of the shaft at Prairie 

 City, in McDonough county, I am indebted to Mr. B. F. Worden, 

 of that place : 



Ft. In. 



No. 1. Soil and drift clay 37 



No. 2. Black fissile rock 1 



No. 3. Cannel coal No. 4? 8 



No. 4- Clay shale...,,..,,,., , ,,.. n 



