ALLEGHENY AND CONEMAUGH IN ANTHRACITE FIELDS 219 



The Mammoth is the great bed of both fields. In the Southern, 

 toward the end of the northern prong, it is but 2 to 4 feet thick ; thence 

 it increases and attains its maximum at the east end of the field, where, 

 within a small area, its splits are united into one bed 114 feet thick with 

 105 feet of coal. Mr Ashburner's section at one locality toward this end 

 shows three splits, 25, 13, and 8 feet, in a vertical distance of 83 feet; at 

 another locality the splits are two, 57, and 16 feet, 95 feet apart, while 

 at a third the bed is single and 115 feet thick. Similar variations occur 

 in the Pottsville and Tremont areas, while northwest, in the Hecksher- 

 ville area, the bed is in two or three splits in a vertical distance of 175 to 

 214 feet. In the western Middle, east from Mahanoy City, the splits 

 are usually three in a vertical distance of 150 to 200 feet; but the in- 

 tervals diminish westwardly until at Shenandoah the bed is single, 40 

 to 60 feet thick. Beyond that place the coal diminishes, and at Shamo- 

 kin the splits are 8 and 7 feet and from 10 to 150 feet apart. Like the 

 Buck Mountain and Skidmore, this is a coal bed much farther west here 

 than in the Southern field. In the eastern Middle the Mammoth is 

 thick everywhere except in a small area within the Black Creek basin, 

 where it is only 12 feet. Ordinarily it is a single bed 20 to 60 feet thick, 

 attaining its greatest thickness in the eastern part of the field; occasion- 

 ally it is in two splits, never widely separated. 



The Holmes coal bed is persistent in the Southern and western Middle, 

 but it has not been recognized in the eastern Middle. It is from 3 to 17 

 feet thick and carries a great proportion of refuse, except in the extreme 

 eastern part of the Southern and the western part of the western Middle, 

 in both of which it is important and yields good coal. 



The Primrose coal bed, like the Mammoth and the Buck Mountain, 

 tends to divide, but the interval between the splits is never great. It 

 varies greatly in thickness within the Southern field and, like the lower 

 beds, decreases westwardly ; yet it is more persistent in that direction than 

 even the Mammoth, for at the last exposure in the northern prong it still 

 has more than 2 feet of good coal. In the western Middle it has 6 to 7 

 feet of coal near Mahanoy City, but westward it is poor, until near 

 Shamokin it becomes important with 7 feet of marketable coal. It is 

 reached at only two localities in the eastern Middle and is not mined. 

 At most places the coal is poor and the bed is known generally as the 

 "Kough coal." 



The Orchard coal bed is persistent in the Southern field, where, unlike 

 the lower beds, it is best only near the beginning of the northern prong; 

 elsewhere it is almost worthless. In the western Middle it is fit to mine 

 only near Mahanoy City and Shamokin, but the refuse at the former 



