TENNESSEE 115 



bed was seen directly under it and almost in contact with the Penning- 

 ton shale.* 



Professor Safford's detailed sections illustrate the formation as it 

 occurs in Fentress, Overton, and Putnam counties, the last two being 

 west and southwest from Fentress, which extends to the Kentucky 

 border. In southwest Fentress he finds both the Rockcastle and the 

 Bonair, the succession being as follows : 



Feet. 



1. Conglomerate [Rockcastle] 40 



2. Shale 51 



3. Sandstone 6 



4. Shale 21 



5. Sandstone ... 46 



6. Shale and sandy shale 50 



7. Conglomerate [Bonair] 90 



8. Coal bed to 3 



9. Fireclay, shale and sandstone 4 



10. Shale and iron ore 25 to 30 



He suggests that coal should occur in the shales, numbers 2, 4, and 6, 

 but no exposure was found. The shales number 10 may belong to the 

 Shenango (Pennington of Campbell). The lower conglomerate, " Main " 

 of SafFord, " Bonair 1 ' of Campbell, forms the cap-rock in much of the 

 region, while the Upper conglomerate, Rockcastle of Campbell, is the 

 cap-rock of much the greater part of Safford's northern division of the 

 Cumberland Plateau in Tennessee. 



In southeast Overton adjoining southwest Fentress, Professor Safford 

 found on the east fork of Obey river a coal bed at 110 feet below the 

 Rockcastle and 54 feet above the Bonair, underlying the sandstone, 

 number 5 of the section just given. This, which is 4 feet thick and 

 yields excellent coal, is evidently the " Sewanee coal bed," so important 

 farther south. The interval between the conglomerates here is 168 feet; 

 it is 174 at a few miles east within Fentress. Farther north in Overton 

 county, say 6 or 8 miles, a coal bed was seen at 180 feet below the Rock- 

 castle, and "at a mile farther east coal beds were seen at 95 and 165 feet 

 below the Rockcastle, 1 foot and 3 feet 6 inches thick ; and Safford says 

 respecting the lower bed " that this is followed not far below by the Main 

 conglomerate." At both of the northern localities the great sandstone 

 between the conglomerates shown in the southern Fentress section is 

 wanting, so that it may not extend farther north than southern Fentress. 

 No details are available for northern Overton, so that the northward 

 extent of the Bonair can not be determined. The presence of this 

 lower conglomerate in Overton county is interesting, for it is absent 



* M. R. Campbell : U. S. Geol. Survey, Standing Stone folio, 1899. 



