>fo. 1851. WAVERLYAN PERIOD OF TENNESSEE— BA88LER. 215 



of the Central Basin. East and northeast of this Chattanooga band 

 of outcrop, a similar black shale, but of undoubted Devonian age, 

 has been mapped as the Chattanooga shale. This shale in central 

 Tennessee will, therefore, according to the present classification, be 

 placed as the first formation of the Waverlyan. The remaining 

 Waverlyan formations of Tennessee form more especially the subject- 

 matter of the present article. 



WAVERLYAN SECTIONS IN TENNESSEE. 



The usual section of Waverlyan rocks in Tennessee is quite simple. 

 Along the eastern side of the Nashville dome the section given in the 

 MclVIinnville foHo of the U. S. Geological Survey is quite typical. In 

 fact, in a study of hundreds of exposures I have seen Httle deviation 

 from it. This section, with the formations Hsted according to present- 

 day nomenclature, is as follows: 



Geologic section of Waverlyan, McMinnville folio. 



Feet. 



Bangor limestone (of St. Louis and Chester age) 



Waverlyan : 



Fort Payne chert — 



Siliceous limestone with heavy beds of chert at the base 150-225 



Maiu-y green shale — 



Light blue to green shale holding glauconite locally and usually 



containing a layer of phosphatic concretions 0-2 



Chattanooga black shale — 



Carbonaceous fissile shale 10-30 



Ordovician limestone (usually of Trenton age) 



At a locality near Woodbury in Cannon County, just a few miles 

 west of the McMinnville quadrangle, Safford has recorded the typical 

 Keokuk fossil Agaricocrinus americanus.^ I have examined this and 

 many other similar sections in the Woodbury quadrangle and find 

 that the stratigraphic succession is identical with the McMinnville 

 section given above. The crinoids come from the basal part of the 

 Fort Payne chert, and as the lowest layers of the overlying Bangor 

 Hmestone contain Lonsdalia canadense,- the whole of the Fort Payne 

 chert falls within the Keokuk of the general time scale. The Chatta- 

 nooga black shale and the Maury green shale afforded no fossils, but 

 Kthologically they are identical with the formations so named in the 

 following sections. Tullahoma, the type-locaHty of the Tullahoma 

 chert formation of Safford and KilHbrew, is but a few miles to the 

 south. Here essentially the same section is presented and the Tulla- 

 homa formation at its type-locaHty is, from all the evidence so far as 

 known, Ukewise of Keokuk age. The Fort Payne chert at its type- 

 locaHty in northern Alabama does not include the St. Louis at its top 

 nor does it contain the Kinderhook shales at its base. It is, there- 

 fore, the same as the Tullahoma, and the latter term is discarded in 

 favor of the former on the ground of priority. 



1 Geology of Tennessee, 1869, p. 342. 



