72 J. J. STEVENSON — LOWER CARBONIFEROUS, APPALACHIAN BASIN 



the limestone becomes 400 feet, while in the northern part of that county 

 the Pennington shales disappear. The limestone contains a 10 to 30 foot 

 sandstone at 150 feet from the top/^ 



The eastern portion of the Cumberland plateau is known as Waldens 

 ridge in Roane, Rhea, and Hamilton counties, the last extending to the 

 Alabama Georgia line. The Newman limestone of Mr Campbell is 

 divided by Mr Hayes into Bangor limestone above and Fort Payne 

 chert below — a distinction more or less exact for the whole eastern out- 

 crop. Mr Hayes finds the Fort Payne 75 feet thick in Roane, but at a 

 little way farther east it is hardly distinguishable from the overlying 

 limestone. It thickens southwestwardl}^ until it becomes 150 feet in 

 Hamilton ; at the bottom it consists almost w^holly of heavy beds of 

 chert with little shale or limestone, while higher up it is more calcareous 

 and passes gradually into the limestone above. This is the silicious 

 group of Safford, t and Mr Haj^es's description enables us to recognize 

 here both divisions of that group, the Protean or Logan below the more 

 calcareous Lithostrotion above. The Bangor of Hayes, equivalent to 

 the Mountain limestone of SafFord and the upper Newman and Pen- 

 nington of Campbell, attains great thickness along this eastern side of 

 Waldens ridge, being apparently nowhere less than 800 feet, while in 

 Hamilton it is reported as 1,100 feet, which, added to the 150 feet of Fort 

 Payne, makes nearly twice the thickness reported from the Chilhowie 

 mountains. In the White Oak mountains, about 15 miles east from 

 Chattanooga and very near the Georgia line, a condition begins which 

 becomes more noteworthy in Alabama. The upper part of the Fort 

 Payne becomes a calcareous sandstone and is separated from the Bangor 

 limestone by from 600 to 800 feet of mostly black car'bonaceous shale, 

 the Floyd shale of Mr Hayes. This he recognizes as contemporaneous 

 with the lower portion of the Bangor farther w^est, for the limestone is 

 but 600 feet thick. The Floyd shale contains a few streaks of impure 

 limestone. A narrow strip of Mississippian is shown on the west side of 

 Waldens ridge in Cumberland, Bledsoe, Sequatchie, and Marion counties, 

 about 12 miles from the east face of the ridge. It is known as the Se- 

 quatchie valle}^ and extends for many miles into Alabama. The Bangor 

 is from 800 to 1,100 feet thick in this valley, and a hard sandstone, 15 

 to 20 feet thick, is seen at manj'' places about 280 feet from the top + 



Outcrops in Georgia. — Somewhat isolated areas of the Mississippian 

 remain in northwestern Georgia, west from the Oostanoula and north 



♦Arthur Keith: U. S. Geol. Survey folios— Morristown, 1896; Knoxville, 181)"); London, 1890; 

 Briceville, 1890; Wartburg, 1896. 

 t •!. M. Sattord : Geology of Tennessee, pp. 338-339. 

 I W. C. Hayes: U. S. Geol. Survey folios— Kingston, 189-2; Chattanooga, 1892; Pikeville, 1895. 



