164 J. J. STEVEKSON — CARBONIFEROUS OF APPALACHIAN BASIN 



appears to be absent from Huntingdon county. This bed is at the Gal- 

 litzin horizon and the Dudley is at that of the Brush Creek.* 



The Georges Creek and Potomac area is farther southwest, beginning 

 in Bedford and Somerset counties of Pennsylvania and continuing across 

 Maryland into West Virginia. The observations in Pennsylvania are 

 somewhat conflicting, but the sections are clear in the other states. The 

 intervals at Barton in Maryland are: 



Feet. Tnches 



1. Pittsburg coal bed 



2. Shales, sandstone, and concealed 143 9 



3. Franklin coal bed and partings 6 10 



4. Shales, sandstone, and concealed 259 



5. Bakerstown coal bed 3 



0. Concealed and sandstone 92 



7. Masontown coal bed 1 7 



8. Shale and sandstone 51 5 



9. Sandstone 33 6 



10. Shale 3 6 



11. Upper Freeport coal bed 



Total 594 7 



The Franklin, or "Dirty Nine-foot," coal bed is thought by Doctor Mar- 

 tin to be at the Little Clarksburg horizon. The Bakerstown is evidently 

 the Barton of Tyson; farther southwest, at Blaine, it is about 357 feet 

 below the Pittsburg and about 90 feet above the Masontown, which is the 

 Brush creek. This lower bed at Blaine underlies the f ossiferous Brush 

 Creek limestone, which is associated with its characteristic black shale. 



The horizon of the Mahoning coal bed is marked at many places by 

 coal seldom more than 20 inches thick, and at one locality in West Vir- 

 ginia Doctor White saw a great thickness of limestone at the Mahoning 

 horizon. The Brush Creek coal bed is thoroughly persistent, usually less 

 than 2 feet thick, though at times yielding nearly 3 feet of coal and in 

 one instance swelling to a mass 9 feet thick, with five benches of coal 3 

 feet 8 inches in all. At one locality it shows 1 foot of coal underlying 5 

 feet of black shale with coal streaks, while at another the upper part for 

 2 feet 5 inches is an alternation of bone, slate, and coal. The Barton is 

 variable, but locally becomes thick and good. The variations in this bed, 

 as shown by figures in volume v, are worthy of careful study, for the bed 

 varies from apparently solid coal 3 feet thick to a double, triple, or even 

 quadruple bed with thick bone at top or bottom, while at times it is a 



* J. J. Stevenson: Bedford and Pulton counties (T 2), pp. 242, 659-662. 

 I. C. White: Huntingdon county (T 3), pp. 47-50. 



