Lyman.] 



306 



LNov. 2, 



been only quite locally thicker there. It seems on the whole very much 

 more likely that Mitchel's coal was the same as Jerrold's. 



Comparison with the Northern West Virginia Section. 



According to Prof. J. J. Stevenson (Trans. Am. Phil. Soc, Vol. 

 XV, pp. 17-31, 1872), the section of the carboniferous rocks of a portion of 

 Monongalia and Marion counties, in the northern edge of West Virginia, 

 near the southwest corner of Pennsylvania, is as follows, from above 

 downward : 



UPPER coal group — MONONGAHELA RIVER SERIES. 



MEAN. 



1. 



2. 

 3. 



4. 



5. 



G. 



7. 



8. 



9. 

 10. 

 11. 

 13. 

 13. 

 14. 

 15. 

 16. 

 17. 

 18. 

 19. 

 20. 

 21. 

 22. 

 23. 

 24. 

 25. 

 26. 

 27. 

 28. 



1, 

 2 

 3 



FT. FT. 



Sandstone, "Waynesburg" 30- tO 35 



Shale 1-15 8 



Coal, "Waynesburg".... 6-9 7 



Sandstone 15 15 



Shale 8 8 



Limestone 5 5 



Shales and sandstone 20 20 



Limestone and shale 30 30 



Sandstone and shale 3) 35 



Limestone 6 6 



Sandstone 15 15 



Limestone 7 7 



Sandstone 10 10 



Limestone 8 8 



Sandstone and shales 23 23 



Shale 1-25 12 



Coal, " Sewickley " 4^-6 5 



Shale 5-8 6 



Limestone 9 9 



Sandstone 4-10 7 



Limestone 22 22 



Coal, "Redstone" 4-5 4 



Fireclay 1 1 



Limestone 12 12 



Shale 5-12 8 



Sand&tone 0-35 17 



Coal, "Pittsburgh" 7-14 10 



Fireclay 3 3 



LOWER BARREN GROUP — BARREN MEASURES. 



. Shale with iron 14 14 



Limestone 2-4 3 



Coal 1^-2 1 



IX. 





 

 6 

 

 

 

 

 

 

 

 

 

 

 

 

 6 

 3 

 6 

 

 

 

 6 

 

 

 6 

 6 

 6 

 



43 



I- 194 



44 



1- 39 



10 



[- 20 



