THE ANTHRACITE STRIP 39 



tion exhibited at Pottsville in the Southern Anthracite field, with the 

 Buck Mountain coal bed as the roof, was taken by J. P. Lesley as equiv- 

 alent to Serai conglomerate, to which he gave the name Pottsville. This 

 term was applied in the Bituminous fields, and the typical section ob- 

 tained by Doctor I. C. White in northwestern Penns3 7 lvania was recog- 

 nized by Professor Lesley as equivalent to that at Pottsville. Doctor 

 White's section is 



Homewood sandstone ; 



Tionesta coal bed ; 



Mercer group, with two or more coal beds and two limestones ; 



Upper Connoquenessing sandstone ; 



Quakertown shales and coal bed ; 



Lower Connoquenessing sandstone ; 



Sharon shales and coal beds ; 



Sharon sandstone — 



a succession which is distinct in a great part of the basin. 



THE ANTHRACITE STRIP 



Location and extent of the fields.— -In the study of the Pottsville forma- 

 tion the same general course will be followed as in the former memoir, 

 but the complexity of conditions in Virginia and West Virginia renders 

 a slight modification necessary, and that area will be examined last of 

 all. The study begins, then, in Pennsylvania with the Anthracite strip. 



The Anthracite fields are three in number, occupying small areas in 

 northeastern Pennsylvania. The Southern, the largest, beginning at a 

 little way from the Susquehanna river, extends eastwardly for about 70 

 miles. Owing to the development of a strong anticline, it forks at the 

 west, and the whole of the Coal Measures passes out in each canoe before 

 the Susquehanna is reached ; but the synclinal basins have been traced 

 far beyond that river by Professor Clay pole, who found that the north- 

 erly basin, curving toward the south, continues through Perry and Cum- 

 berland counties into Franklin, where it is distinct until within 40 miles 

 of the Maryland line, or to about the latitude of the Broad Top coal 

 field, in Bedford and adjacent counties. This Southern field lies wholly 

 east or southeast from North or Tuscarora mountain and is within the 

 Great valley. 



The Middle field, divided into the western Middle and the eastern 

 Middle, lies next toward the north. The western Middle is practically 

 in contact with the Southern at the most northerly point of the latter, 

 and extends rudely parallel to it for upward of 30 miles, but reaches 

 hardly so far westward. The eastern Middle, farther north, overlaps 

 the western for a few miles at its west extremity and extends east almost 



