46 ECONOMICAL GEOLOGY. 



I refer No. 16 in this shaft to the horizon of coal No. 7, mainly 

 from its stratigraphical position, but it is not impossible that it 

 may represent No. 6 instead. No fossels were found in connection 

 with it, at the only outcrop of the seam I was enabled to examine, 

 and hence its stratigraphical position is the only evidence that was 

 available for its identification. The outcrop of this coal was found 

 in a deep ravine, just below the uplift at Split Rock, where an 

 opening had been made to procure the potter's clay, which forms a 

 heavy bed immediately below the coal. 



Two miles and a half north of La Salle, one of the deepest shafts 

 in the county has been sunk by the Caledonia Coal Company, and 

 the following details of it were kindly furnished by the pit boss, Mr. 

 JOHN P. DUNCAN: 



Ft. In. 



No. 1. Drift clay and gravel 13 



No. 2. Green and purple shales, with thin bands of impure limestone and a 



thin coal seam 60 



No. 3. Limestone, in two beds 27 



No. 4. Blue, green and gray shales 215 



No. 5. Black slate 8 



No. 6. CoalNo.7(?) 4 



No. 7. Fire and potter's clay 16 



No. 8. Clayshale 14 



No. 9. CoalNo.5 3 6 



No. 10. Fire-clay 5 



No. 11. Sandstone 5 



No. 12. Clayshale ." 54 



No. 13. Brown shale., 90 



No. 14. Blackslate 2 



No. 15. Sandstone 14 



No. 16. Black slate 2 



No. 17. Clayshale 14 



No. 18. Coal No. 2... 3 10 



Total depth 550 4 



The lower seam is the one worked at the present time, in this 

 shaft, and it is said to be underlaid here by a bed of excellent fire 

 clay, from 12 to 14 feet in thickness. The coal which it affords is 

 superior in quality to that from either of the upper seams. 



The beds above the main limestones, No. 3 of the Caledonia 

 shaft, were found well exposed, in the big cut on the Illinois Cen- 

 tral railroad north of the zinc works, and the following is a detailed 

 section of them as they appeared there : 



Feet. 



No. 1. Green and ash-gray clay shales 4 



No. 2. Nodular calcareous shale 8 



No. 3. Greenish clay shale 12 to 15 



No. 4. Impure chocolate- colored limestone 2 



No. 5. Red and green shales 10 



No. 6. Green, shaly clay 8 



