44 



moreover, hold a similar relation to our primary rocks throughout 

 their entire range, from Vermont to Alabama, separated from 

 them by no other group of strata yet discovered, claiming an 

 earlier origin, I have deemed it expedient, for the sake of classi- 

 fication, to confer upon them the title of the Older Secondanj Strata 

 of the United States. Constituting ahnost the entire chain of the 

 Appalachian or Alleghany system of mountains, in which the 

 whole series is not only much more complete but better developed 

 than in an any other region of the continent, I have thought it 

 judicious elsewhere in my geological descriptions to propose 

 for these rocks the synonyme of the Appalachian System of 

 Strata.* 



Comparing them with the older secondary rocks of Europe, 

 Ihey are evidently related, as respects their date, more nearly to 

 the English silurian strata than to any other known system. The 

 probable extent of their affinity to these will be touched upon 

 under another more suitable head. 



Confining our attention in this place to those members of the 

 older secondary series which enter the territory of the State, they 

 will be found to comprise the five lon-ermost formations of that 

 extensive group, together with the lower division of the eighth 

 (the sixth and seventh being absent), counting always in the 

 ascending order. 



ThQ first, or lowest of these, seen only in two or three localities, 

 is a white sandstone, Formation I. of the general Appalachian 

 series ; the second in the order of superposition, is the blue lime- 

 stone of the Kittatinny Valley and its branches, and is Forma- 

 tion II. of that group ; the third great stratum is the slate of the 

 same wide valley, and in the general series is Formation III. ; 

 the fourth is the rock of the Kittatinny, or Blue Mountain, a 

 gray sandstone, passing into conglomerate, and is designated as 

 Formation IV.; the fifth is the red sandstone. Formation V., 

 occupying the northwestern flank and base of the Kittatinny 

 Mountain; while the sixth, and uppermost, is the blue fossiliferous 

 limestone, skirting the valley of the Delaware, from Wallpack 

 Bend to Carpenter's Point, being the lower division of Forma- 

 tion VIII. of the same Appalachian system. 



* See Annual Reports on the Geological Survey of Pennsylvania. 



