226 J. J. STEVENSON CARBONIFEROUS OF APPALACHIAN BASIN 



In the deep basin between Wilkesbarre and Nanticoke, there are above 

 the Hillman several coal beds, some of which are fairly regular; but the 

 accumulation of coal in available beds seems to have ceased at about 1,200 

 feet above the Eed Ash bed and the higher measures are barren; south- 

 east from Nanticoke to Dundee the upper measures for 900 feet have 

 been proved by borings to be without workable coal. 



Respecting the relations of the coal beds in this field to those in the 

 others, nothing can be determined by stratigraphy; a gap of almost 25 

 miles separates the areas. The Red Ash and the Baltimore are supposed 

 to be equivalent to the Buck Mountain and Mammoth respectively. The 

 important Shaft, or Archbold bed, evidently disappears southward before 

 reaching the Nanticoke area, and the Baltimore, the second important 

 bed above it, becomes so obscure and uncertain that its equivalent in the 

 Nanticoke region is still undetermined. The only coal beds retaining 

 their importance are the Red Ash, or Dunmore; the Ross, which, owing 

 to disappearance of the Archbold, becomes the second bed, and the Hill- 

 man. It has been seen that in the nearest portion of the eastern Middle 

 the Mammoth and Skidmore prove to be one bed, and that the interval 

 between that bed and the Buck Mountain is so diminished as to suggest 

 that they may unite at but a little way northward. It seemed possible, 

 therefore^ to seek in the Red Ash of the northern field the equivalent of 

 the Buck Mountain, Skidmore, and Mammoth; but this suggestion ap- 

 pears to be contrary to the evidence furnished by plant remains, as read 

 by Mr David White, so that it may not be accepted. The solution of the 

 problem remains with the paleontologist. 



The material filling intervals between coal beds in the northern end 

 of this field is for the most part rather fine. Sandstone prevails above 

 the Clifford-Dunmore, and one section shows 51 feet of conglomerate 

 resting on that bed ; but, higher up, sandstone and shale are in alternating 

 beds. Near Carbondale the sandstones are fine and the proportion of 

 slate is large, but near Jermyn the sections show little aside from sand- 

 stone. This is the condition near Olyphant even to the Diamond coal 

 bed. On the easterly border, near Winton, conglomerate appears in most 

 of the sections between the Dunmore and Clark beds; but in the Price- 

 ville-Dunmore-Scranton region coarse rocks are usually wanting and 

 shale is present in great proportion for 240 feet above the bottom. The 

 change from sandstone to slate is very abrupt in many places and a 

 record in Scranton shows a notable bed of conglomerate. 



Farther southwest one finds a persistent conglomerate above the Red 

 Ash in the Lackawanna-Pleasant Valley district; it is within the first 

 120 feet above that coal bed, and varies from 9 to 80 feet in thickness. 



