36 J. J. STKVENSOX LOWER CARBONIFEROUS, APPALACHIAN BASIN 



enabling us to recognize the Protean of Safiford as distinguished from 

 the more calcareous Lithostrotion bed above. This Protean is traceable 

 easily into Alabama, where it is the Lauderdale of McCalle^^ and extends 

 far southward be3'ond the Grainger, resting for a great part of the dis- 

 tance on the still lower Chattanooga shales. In the southeasterly ex- 

 posures it becomes very thin and disappears before southern Shelby 

 county of Alabama has been reached. But much farther north it seems 

 to have been lost in the overlying Tuscumbia, equivalent to Safford's 

 Lithostrotion. The Lauderdale is sharply defined along Wills valley in 

 front of the Cumberland plateau as well as in Browns valle3^ within 

 that pleateau. It consists almost wholly of chert and disappears south, 

 so that it is recognizable onh^ with doubt in Bibb county of central 

 Alabama. 



The ivedern outcrops in Alabama, Tennessee, and Kentucky. — On the west 

 side of the plateau, the Lauderdale is practically the newest formation 

 exposed in the northwestern three counties of Alabama, where it con- 

 tains much limestone with much bedded chert, in this respect differing 

 from the overlying Tuscumbia, in which the chert is usuall^^ nodular, 

 rarely bedded. Its thickness varies from 175 to 225 feet.^ 



In Tennessee, Mr Hayes does not separate the Protean from the over- 

 lying Lithostrotion, but includes tbem both under the term Fort Payne, 

 but his reference to the abundance of chert in the lower portion enables 

 one to recognize the Lauderdale near the Alabama border.f Farther 

 north, in White county, Professor Safford gives a section of the Protean, 

 thus : 



Feet 



Limestone, cherty 100 



Limestone, without chert 30 



8haly rock 20 



Limestone and chert 127 



Total 277 



Chert increases downward, so that in the bottom 100 feet there is 

 merely a succession of chert beds separated by thin layers of crinoidal 

 limestone. Northeastward from White county a marked change occurs, 

 for in the next county the section is 



Feet 



Sandstone . ... 8 



Blue limestone, coarse, fetid 45 



Interval, nmch chert 216 



Total 265 



* For references to Mr McCal ley's Alabama reports, see chapter ii, where the whole series as it 

 occurs ill that state is described. This is necessarj' beoanse at many localities the separation of 

 Lauderdale and Tuscumbia will remain impossible until after much closer study has been made- 



fC. \V. Hayes: U. S. Geol. Survey folios. Sewanee, 1894; McMinnville, 1895. 



