178 TRANSACTIONS OF THE 



In the same valuable report, which combines a greater 

 mass of useful practical information on the subject of 

 Pennsylvania coal than has ever before been presented 

 to the public, the writer of the article Number 27 in the 

 Appendix, at page 122, appears to have formed the same 

 conclusion, in classing the coals of Cumberland, Wills' 

 creek, and the Round Top (Broad Top?) mountain, on 

 the Raystown branch of the Juniata, with the secondary 

 bituminous coals of Clearfield and Lycoming. 



Having had some opportunities of investigating the 

 relative ages and geological order of position in most of 

 the deposits referred to, I feel no hesitation in assign- 

 ing the Bedford county coals, particularly the veins in 

 the Broad Top mountain, to their true position among 

 the grauwacke, or, as they are commonly denominated, 

 the transition rocks ; and in referring in all cases, from 

 the Potomac to the Susquehanna, the boundary between 

 the secondary coal field and the transition series contain- 

 ing the older coal beds, to the main range of the Alleg- 

 hany mountains. 



In every part where I have examined this mountain, 

 from its base upwards, the order of superposition is so 

 apparent, so constant, and so well defined, that it pre- 

 cludes all room for doubt. If there is one case in the 

 entire system of North American rocks, distinguished 

 from the rest by the absence of ambiguity, this is that 

 one. 



The old red sandstone (for as a group it were well 

 to retain a long known characteristic nomenclature) is 

 every where seen supporting the almost horizontal secon- 

 dary carboniferous formations, whose compact quartzose 

 grits and conglomerates, form the crest of the Alleghany 

 ridge, and the solid platform by which its highest table 

 land is maintained.* 



* In referring the old red sandstone to a position corresponding with its 

 place in the series of European rocks, and to which the American group 



DSl 



