ECONOMICAL GKOLOGY. 39 



Greenville is undoubtedly located upon the line of one of the 

 ancient valleys that were excavated either at the commence- 

 ment of the drift period, or during the elevation of the surface 

 above the carboniferous sea beneath which the coal measure 

 rocks \\ere formed, and by comparing the boring at Greenville 

 with the shaft at Smithboro, we find the ancient valley attained 

 a depth of about one hundred feet more at Greenville than at 

 the latter point. A notable feature of the drift at Greenville, is 

 the great amount of sand and gravel which it contains, and 

 the small amount of clay. The 90 feet described as conglom- 

 erate by the men in charge of the boring, was probably a bed of 

 gravel, cemented either with ferruginous or calcareous material 

 such as may be frequently observed in surface outcrops of the 

 drift deposits. 



The coal shaft at Sorento, in Bond county, at a depth of 373 

 feet, penetrated a coal seam 8 feet in thickness. For the fol- 

 lowing copy of the n-conl J am indebted to Mr. Walton Kut- 

 ledge the mine inspector of that district: 



No. Ft 



1. Soil and clay 17 



2. Conglomerate 28 



3. Clay shale 20 



4. Limestone I 



5. Clay shale 4 



6. Light gray limestone 20 



7. Light limestone and chert 8 



X. Fin- clay j 



9. Black slate 



I", i 'lay shale w 



11. Red shale 



1 1'. ('.'< >al " m " m j 



13. Fire clay 



14. Brown shale ^ 



15. Light shale , 



Iti. Clay sha!< 



17. Magnesian limestone 



18. Clay shale '.'.'..'".'. 20 



19. Brown shale 



20. Light shale 



NoTE.-The sections of drift reported in connection with the coal shafts and 

 borings given in this chapter, were mainly obtained after the preceding chapter was 

 written, and tend to confirm the position hitherto assume,! j n regard to the origin of 

 the drift beds, and demonstrate very clearly to the mind of the writer, that they are 

 not the accumulations of land ice, but are largely if not wholly due to aqueous agencies. 

 A. H. \\ , 



