Stevenson.] Jibo • [jan. 21, 



3. Dark fissile shale, with thia beds of sandstone, partial 

 exposures between Mendota and Moccasin gap, 

 but best sliown in the gap 150' 



Total 830' 



The sandstone beds in No. 3 are fine-grained, very white and prove to be an 

 excellent firestone. These are shown in the Abingdon road at several locali- 

 ties between Mendota and Moccasin gap, as well as just below the mouth 

 of the gap. Much of this material was used for lining at Bushong's fur- 

 nace, 40 miles away in Tennessee, to which it was carried by wagon. The 

 shales are very dark, and at many localities along the foot of Clinch moun- 

 tain they are as badly wrinkled as mica schist, but they show no evidence 

 of metamorphism. Two thin beds of highly carbonaceous shale occur at 

 the base of this group, which have been mistaken at several places for coal. 

 They contain enough carbonaceous matter to burn and sometimes they 

 yield a piece of fairly good coal. 



The Chemung rocks are shown in all the ravines crossing the first ridge 

 of Brushy mountain. An excellent exposure is afforded by the railroad ex- 

 cavation near the North Fork of Holston river, where the group is represent- 

 ed by shales and sandstone, mostly brownish gray and not far from 300 feet 

 thick. A conglomerate layer, 4 to 6 inches thick, was seen very near the 

 top and another of about the same thickness at 20 feet loM'^er. Fossils 

 were found immediately above the upper layer as well as at 10 feet below 

 it ; among these are Spirifera dinjuncta, Atrypa anpera and a Ghonetes. 

 For the most part the specimens are badly preserved, as the layers in 

 which they occur are ferruginous grits and the fossils are recognizable only 

 on the weathered surface. Spirifera disjwieta and Produciella hoydii were 

 found on fragments of sandstone belonging midway in the group, and a 

 Spiropliyton covers many layers near the base. 



The Chemung is succeeded by the lower member of thesilicious group of 

 the Lower Carboniferous. The two groups are conformable, and the junc- 

 tion is well shown in the railroad cut. 



A good section of the Lower Carboniferous was obtained between this 

 point and the Holston fault by following the railroad line. It is as fellows : 

 Mountain Limestone Oroup. 



1. Sandstones, limestones and shales 800' 



2. Calcareous shales 60' 



3. Concealed 40' 



4. Calcareous shale 100' 



5. Limestone 105' 



6. Imperfectly exposed 250' 



7. Limestone 15' 



8. Shales 20' 



9. Limestone 50' 



10. Sliale, imperfectly exposed 65' 



11. Limestone 15' 



