1881.1 ^OL [Stevenson. 



1. Shales and sandstones, with some thin limestones 705' 



2. Limestones and calcareous shales 150' 



under which comes the massive limestone of the Silicious group. But in 

 Brushy mountain, where the exposures are almost complete, the section is : 



1. Shales and sandstones, with thin limestones 800' 



3. Limestones and calcareous shales 1470' 



No measurements were made on Powell mouDtain, but the thickness of 

 the group is not materially different from that shown in the Stone moun- 

 tain gaps. The succession is complete on the Holston, and the exposures 

 are so good that there is not the slightest reason to suspect a fault ; as, in- 

 deed, will be apparent to any one who will consult the detailed section 

 given in the chapter on the Holston area. The shales and sandstones on 

 top are more or less calcareous ; some of the sandstones are almost sky- 

 blue, and they break with an irregular fracture ; others are calcareous 

 grits, but there are some which are comparatively soft. Several beds are 

 used for the manufacture of hones and grindstones. This part of the group 

 is well shown in Pennington's ga.p, when the river is low. It is exposed 

 also in the "Wolf creek gorge, which is followed from Holston river by the 

 Bristol Narrow Gauge Railroad. 



The greater part of the lower division in Stone mountain consists of cal- 

 careous shale, there being comparatively little limestone ; but in Brushy 

 mountain, there is very little shale, and many of the limestone beds are re- 

 markably free from foreign matter ; chert occurs in small quantity in some 

 of the lower beds both in Stone mountain and near the Holston. 



Fossils characteristic of the Chester limestone occur plentifully in some 

 beds at all localities. Pentremites godonii, Productus semi-reticulatus and 

 an undetermined ZapJirentis were found in Hunter valley ; Productus semi- 

 retici(,latus, Hemiproniies crassus, Spirifera leidyi, Athyris stibquadrata, 

 Oyrtoceras, Fenestella and Zaphrentis sptinuUfera were obtained in Penning- 

 ton's gap ; in Brushy mountain the stems of crinoids and Ohonetes are com- 

 mon in some of the shale beds of the upper part of the group. The higlier 

 limestones are made up mostly of a Fenestella, with occasionally a Zaph- 

 rentis or a Productus ; while in the lower limestones crinoid stems, 

 Fenestella, Zaphrentis, Productus cora, Productus elegans, Spirifera leidyi, 

 Athyris subquadrata, Pinna missouriensis ? , and J.Z?(?risma are very com- 

 mon, along with other forms not recognized during the hurried examination. 



The Silicious Group. 



In Tennessee, according to Prof. Satford's statement, this group is double, 

 consisting of 



1. The Lithostrotion or coral bed, a cherty limestone, fossiliferous and 

 everywhere characterized by Lithostrotion canadense. 



2. The Lower or Protean member, variable, mostlj" silico-calcareous ; 

 often limestone ; often sky-blue ; contains much chert in its middle and 

 lower portions ; sometimes beds of crinoidal limestones. 



