EASTERN EDGE OF ALLEGHENY PLATEAU 53 



but the lower plate is less coarse.* Doctor White measured the forma- 

 tion on the westerly side of the basin in Somerset county, where the 

 beds rise toward the Allegheny mountains, and obtained the following 

 section : 



Feet. Inches 



1. Massive sandstone 75 



2. Mount Savage coal bed 4 



3. Mount Savage fireclay. 7 6 



4. Conglomerate sandstone 125 



5. Sandstone and shale 110 



6. Coal and shale 8 



7. Impure fireclay 10 



8. Shales 20 



9. Massive sandstone 35 



in all, 288 feet 2 inches. The same observer measured the formation on 

 the Potomac river near Westernport, Maryland, and Piedmont, West 

 Virginia ; also on the western side of the basin, where the succession is f 



Feet. Inches 



1. Sandstone (Homewood) 20 



2. Coal bed 2 



3. Dark shale with fossil plants 45 



4. Hard massive sandstone 40 



5. Shales and sandstone . . '. 42 



6. Coal bed 16 



7. Fireclay, shale, and sandstone 42 



8. Coal bed 16 



9. Shale and flaggy sandstone 42 



] 0. Pebbly sandstone 45 



11. Coaly shale 5 



12. Sandstone and shale 195 



13. Coal bed 10 



14. Sandstone and shale 110 



Total. 473 



Mr O'Harra gives as an average section of the formation in the Poto- 

 mac region in Maryland the following J (condensed from the original) : 



Feet. Inches 



1 . Massive sandstone 20 



2. Coal bed, Westernport 2 



3. Shales and sandstones 127 



* J. J. Stevenson (T 2), p. 100. 



fl. C White : Stratigraphy of the Bituminous coal field in Pennsylvania, Ohio, and West Vir. 



ginia. Bull. U. S. Geol. Survey, no. 65, 1891, p. 186. 



I C. C O'Harra : Maryland Geological Survey, Allegany County, 1900, p. 114. 



i 



VIII— Bull. Geol. Soc. Am., Vol. 15,1903 



