STRATIGRAPHIC SUMMARY. 639 



continental and marine and in the southwest largely of marine 

 origin with a change toward continental sedimentation at the top. 

 In the Appalachian region and the bituminous district of Ohio and 

 western Pennsylvania, the following divisions are recognized 

 (mostly continental sediments) : 



Permic. 



Dunkard formation (Upper Barren Coal Measures). 



Carbonic (Pennsylvanic). 



Monongahela formation (Upper Productive Coal 



Measures). 

 Conemaugh formation (Lower Barren Coal Measures). 

 Alleghany formation (Lower Productive Coal Measures). 

 Kanawha formation (Eastern Lower Productive in part). 

 Pottsville formation (Millstone grit). 



The Pottsville of the type section admits of division into four 

 parts: (i) Lower Lyckens, (2) Lower intermediate, (3) Upper 

 Lyckens and (4) Upper intermediate. In the northern Appalach- 

 ians a number of lithologic divisions are recognized. In the Great 

 Flat Top region of Virginia and West Virginia and in the New 

 River gorge these include :^^ 



Fayette or Nuttall sandstone no ft. 



Sewell formation 368 ft. 



Raleigh sandstone 80-155 ft. 



Quinnimont shale 300 ft. 



Clark formation 380 ft. 



Pocahontas formation 360 ft. 



The Lee conglomerate and Lookout sandstone are partial repre- 

 sentatives of the Pottsville in other parts of the southern 

 Appalachians. 



The Kanawha series, about 1,200 ft. thick in the type region, 

 rests upon the Fayette or Nuttall sandstone and is capped by the 

 Charlestown sandstone. It is of continental origin throughout and 

 contains a number of workable coal beds. 



In Ohio and western Pennsylvania, the beds below the Alleghany 

 comprise : 



^'•Pocahontas Folio. 



