116 J. J. STEVENSON — CARBONIFEROUS OF APPALACHIAN BASIN 



from western Fentress except in the extreme southwest. Professor 

 Safford's section at 4 miles west from Jamestown, near the Overton 

 border, shows a very abrupt change to the conditions described by Mr 

 Campbell in Fentress county, for the succession is 



1. Conglomerate, very heavy Not measured 



2. Shale and sandstones 97 to 102 



3. Coal bed 3 to 4 



4. Concealed 4 



5. Sandstone 20 



6. Concealed to the Mountain Limestone 30 



The coal bed is evidently the Sewanee, shown in southeast Overton 

 at 54 feet above the Main (Bonair) conglomerate. The* whole thickness 

 below the Rockcastle is but 158 feet. At 6 miles east from Jamestown, 

 in Fentress county, coal beds are shown at 40 and 61 feet below the 

 Rockcastle, the lower bed being 4 to 5 feet thick. 



Putnam county is south from Overton. Apparently there is little 

 here above the Main (Bonair) conglomerate, which in the central part 

 of the county is thin, with an unusual thickness of shale above and 

 below it, so that Professor Safford thinks it largely replaced by shale. 

 A thin coal bed, 2 feet, was seen above the conglomerate, and an 

 important though variable bed is directly under it. The underlying 

 shales vary greatly, for on Sinking Cane they are almost 100 feet, 

 whereas on Calfkiller creek, barely a mile away, they are but 61 feet.* 



Evidently Professor Safford regarded the conglomerate of western 

 Fentress as his Main conglomerate, but in view of the studies made in 

 Fentress and Cumberland by Mr Campbell and in eastern Fentress by 

 Mr Keith, the deposit must be taken as the Rockcastle of Campbell. 

 The Bonair, according to Mr Campbell, extends but little beyond Mon- 

 terey in Cumberland county, for it changes northwest from that point 

 and the shales underlying the Rockcastle are very much thicker there 

 than elsewhere. Though present in Overton, as shown by Safford's 

 sections, it is clearly wanting in much of Fentress. Its boundary is a 

 line from southwest Fentress northeastward, and passing just west of 

 Rugby, where oil borings prove its presence. Mr Campbell sa} 7 s that it 

 is unknown farther north on the south fork of Cumberland river, so that 

 it must be confined to southwestern Fentress. 



Southward from Fentress, Putnam, and western Cumberland, along the 

 western border, one has the work of Professor Safford and Mr Hayes to 

 the Alabama line. It may be well to adopt, for convenience of descrip- 

 tion, Professor Safford's division of the area, considering first the region 



J. M. Safford ; Geology of Tennessee, 1869, pp. 393, 396, 397, 398. 



