46 ECONOMICAL GEOLOGY. 



Total thickness .................................................................. 899 3 



The strata reported above seem to be about 13 feet more in 

 thickness than the depth of the shaft as measured after the 

 completion of the work. 



A boring at Hillsboro, in Montgomery county, made by the 

 Chicago Diamond Drill Company, was carried to the depth of 

 769 feet, and penetrated through the lower coal measures, and 

 into the upper division of the Lower Carboniferous formation. 

 The following is a copy of this boring kindly furnished by Mr. 

 Geo. C. Bryce: 



Ft. In. 



1. Yellow clay, sand and pebbles ...................................................... 14 



2. Hardpan .............. ................................................................. 23 



3. Quicksand ............................................................................ 1 



4. Hardpan ............................................................................... 16 



5. Yellow clay ........... '. ............................................................... 7 



6. Sand and gravel ...................................................................... 20 



7. Blue clay .............................................................................. 26 



8. Coarse sand and gravel .............................................................. 16 6 



9. Limestone ............................................................................. 8 



10. Clay shale ............................................................................. 52 6 



11. Limestone (Shoal Creek) ............................................................. 8 



12. Bituminous shale ..................................................................... 1 8 



13. Coal, No. 9 ............................................................................ 8 



14. Clay shale ............................................................................. 29 8 



15. Sandy shale and sandstone .......................................................... 65 



16. Fireclay. (Horizon of coal No. 8) .................................................. 8 



17. Sandy shale ........................................................................... 24 



18. Sandy slate ............................................................................ 78 



19. Clay shale, upper part nodular ..................................................... 9 



20. Hard limestone ....................................................................... 5 6 



21. Clayshale .............................................................................. 11 6 



22. Limestone ............................................................................. C 



