102 



THE DEVONIAN AND CARBONIFEROUS. 



[bull. 80. 



tions, strictly speaking, are concerned, this was the case down to 

 details which were variable in the different counties of Pennsylvania. 

 As to the classification, the separation of the Conglomerate series from 

 the Lower Goal Measures was not found to express an actual change 

 in nature of the formations in eastern Ohio; and as late as 1884 Mr. 

 Orton, then State geologist, united these two, calling them both Lower 

 Coal Measures. 1 



In the sixth volume 2 the Coal Measures are classified as Carbonifer- 

 ous, thus : 3 



Feet. 



f 17. Upper Barren Coal Measures 500 



| 16. Upper Productive Coal Measures 200 



Carboniferous <( 15. Lower Barren Coal Measures 500 



I 14. Lower Productive Coal Measures 250 



i 13. Conglomerate group 250 



This is practically the Pennsylvanian classification. 



In the results already discussed, coal beds, as lithologic formations, 

 have been the chief means used in the classifying and correlating the 

 Coal Measures. 



Fossil plants served to distinguish the Carboniferous from the Triassic 

 and the Cretaceous Coal Measures, but have not heretofore been of much 

 use in subdividing the beds into groups. 



In Virginia and West Virginia the character of the plants found in 

 the Upper Barren Measures led Mr. Fontaine to correlate them with the 

 Permian formations of Europe. 



The report of his study of the plants and of Mr. White's study of the 

 structure is given in Eeport PP of the Second Pennsylvania Survey. 4 



A brief account is given of the floras of the Vespertine group (Pocono 

 formation), Conglomerate group (Pottsville formation), Lower Produc- 

 tive Coal Measures, particularly the Kittanuing Coal an<J the Upper 

 Freeport horizons, Lower Barren Measures, Upper Productive Coal 

 Measures, including the Waynesburg coal beds and the Upper Barren 

 Measures. The flora of the last formation, including the roof shales of 

 the Waynesburg coal, beds, is discussed at length, and the species 

 described and figured, the authors reaching the conclusion that the 

 " Upper Barrens of the Appalachian coal field are of Permian age." 5 



Most of the species described are from the roof of the Waynesburg 

 coal, and the authors suggest that " perhaps it might be best to sepa- 

 rate the roof shales of the Waynesburg coal and Waynesburg sandstone 

 and consider them transition beds, and the strata overlying and includ- 

 ing the great limestone below the Sewickley coal are to be considered 

 strictly Permian." 6 



1 Geol. Survey of Ohio, vol. 5, p. 10. 



* Ibid., Economic Geology, vol. 6, 1888. By Edward Orton. 

 s Ibid., p. 3. 



4 The Permian or Upper Carboniferous Flora of West Virginia and SW. Pennsylvania, by Wm. M. 

 Fontaine and I. C White, 1880, pp. 143, Pis. xxxvill. 

 6 Ibid., p. 110. 

 6 Ibid., p. 120. 



