COAL MEASURES. 5 



Ft. In. 

 No. 4. Coal, No. 1 ljto 5 



No. 3. Silicious sbaly fire-clay, containing Stigmaria Jicoides 2 to 3 



No. 2. Silicious shales, with concretions of carbonate of iron. In Gallatin county this bed 

 is from sixty to seventy feet in thickness, but is not found at all in the northern 



portion of the State to 70 



No. 1. Coarse sandstone or conglomerate forming the base of the Coal Measures. In the 

 southern portion of the State it is largely developed, with.au average thickness of 

 more than a hundred feet, but in the northern portion it is seldom found attaining 

 a thickness of more than twenty-live to thirty feet, and is often wanting altogether. 

 It appears at several localities in "Whiteside county, as outliers, of considerable 

 thickness, several miles beyond the present boundary of the coal field. Its thick- 

 ness usually ranges from 20 to 110 



Stems of Sigillaria and Lejridodendron are almost the only fossils it 

 affords, and eveu these are seldom found in a condition to be specifically 

 determined. 



The deepest shaft yet sunk in the State is the one at Centralia, which 

 commences about the horizon of coal No. 11, and has been carried down 

 to the depth of 576 feet. The following is a correct copy of the record 

 kept of the thickness and general character of the beds passed through 

 in this shaft, and is inserted here for comparison with the general 

 section, and with others that may hereafter be sunk through the corre- 

 sponding strata in other portions of the State. 



Shaft at Centralia. 



Ft. In. 



No. 1. Drift clay and aoil 12 



No. 2. Soapstone (clay shale) 11 



No. 3. Bine shale 47 



No. 4. Shale 8 



No. 5. Limestone 1 6 



No. 6. Coal 8 



No. 7. Blue shale 24 6 



No. 8. Soapstone (clay shale) 2 



No. 9. Limestone 5 6 



No. 10. Hard sandstone 5 



No. 11. Coal 2 



So. 12. Soft sandstone 6 



No. 13. Coal 6 



No. 14. Sandstone 2 6 



No. 15. Coal ■. 2 



No. 16. Soapstone (clay shale) 4 



No. 17. Limestone 2 



No. 18. Sandstone 12 2 



No.19. Bluerock 1 C 



No. 20. Fire-clay 2 



No. 21. Soapstone (clay shale) 15 6 



No. 22. Blue shale 29 



No. 23. Limestone (Carlinville bed) 11 



No.24. Shale 5 C 



No. 25. Coal 4 



No. 26. Clay shale 4 



No. 27. Sandstone 10 



No. 28. Shale 50 



No. 29. Limestone 1 



No. 30. Shale 2 



No. 31. Soapstone (clay shale) 3 



No. 32. Sandstone 24 



