1877.] 5^*^ [Ashburner. 



XII. Pottsville {Send) Conjlomerate, {Millstone Grit). 



30' 



\ 280' 



Upper member (Piedmont sandstone) No. 250 160' 



Middle " (Kanawlia River series\ Nos. 249, 48, 47, 46. . 40' 

 Lower " (No. XII proper) Nos. 245 and 244 80' 



1. The Upper member, or (Piedmont sandstone) consists of tliree parts : 

 upper white and reddish-white and gray, flaggy sandstone and conglomer- 

 ate ; in the middle part the conglomerate predominates, the pebbles liere 

 being the largest, but very irregularly distributed, while the strata them- 

 selves exhibit false bedding in a marked degree. The lower part of this 

 member is composed, principally, of thinly bedded and couglomeritic 

 sandstone. 



The beds of conglomerate do not seem to be persistent. It would appear 

 as if a bed, in force in one locality, feathers out from a centre of maximum 

 thickness in all directions and disappears entirely, while an upper or lower 

 conglomerate bed has its minimum tliickness at the very locality where the 

 other is at its thickest. 



Dr. Newberry, in Vol. II, Geology of Ohio, p. 107, suggests the origin 

 of the conglomerate in No. XII as being due to icebergs. He says, " From 

 the similarity of the deposits now being made by icebergs, over various 

 portions of the sea bottom, with tliose made by the same agency during 

 the Drift Period, and of both to the materials composing the carboniferous 

 conglomerate, I have suggested the possibility that they might all be pro- 

 ducts of the same agency. In this view tlie conglomerate should be com- 

 pared with the kames and eskers of the drift. This tlieory, liowever, is 

 not insisted upon, but is simply a suggestion, which has sprung from a 

 conviction of the entire inadequacy of any other solution of the problem 

 yet offered." 



2. The middle laemher, or Kanawha River Coal Series, so named from its 

 great development along the Kanawha River, in "West Virginia, consists 

 of sandstones and shales containing a seam of coal. No. 248, about 2 feet 

 thick, which represents undoubtedly the Mount Savage coal bed. This 

 set of beds resembles strongly in general cliaracter the rocks of the lower 

 productive coal measures. 



The coal bed No. 248 is overlaid by sandstone and shale No. 249, and 

 underlaid by massive gray sandstone No. 247, exliibiting f^xlse bedding, 

 with probably a bed of fireclay between the sandstone and coal. The 

 seam was located in many places on Wray's Hill and Rocky Ridge, but 

 there was only one locality (Rocky Ridge, west end of Wray's Hill tun- 

 nel) where its tliickness could be determined and it was impossible on ac- 

 count of water in the opening to ascertain tlie exact nature of the under- 

 lying stratum. 



No. 246 at the bottom of the middle member is 7 feet thick and (17 feet 

 below the coal seam) is composed of dark gray and black slate and slaty 

 sandstone ; the slate predominating. A small seam of coal was reported 

 to have been found in the black slate, but it is a little doubtful, as no traces 



