Stevenson.] '^'^^ [Jan. 21, 



The general structure, then, must be as represented in Fig. 6, which shows 

 also the structure of Powell mountain. The Quinnimont series caps the 



^y- 



^ 



a. ^ & 



Fig 6 —Cross-section along Stony creek through Powell mountain and Buck- 

 ner's ridge, a, Powell mountain ; 6. Buckner's ridge. Numbers as in Fig. 1. 



bluff overlooking the valley of South Fork of Powell river. Thence for 

 several miles the dip is gentle, but within somewhat more than a mile from 

 the fault it suddenly increases, becoming rather more than 30 degrees, 

 and at the last exposure of the rock it is nearly 45 degrees. This change 

 in rate is so abrupt that where the narrow valley follows the line of change, 

 a fracture at once suggests itself as the only explanation of the condition. 

 It is altogether probable that a close, sharp fold exists within two or 

 three miles south-east from the Hunter Valley fault. The shales alongside 

 of Clinch river above the mouth of Stony creek are violently twisted and 

 the plications are as close as those frequently seen in Archaean schists. The 

 shales themselves in many places are jointed and have an indistinct slaty 

 cleavage ; but they show no other signs of metamorphism. The rock 

 forming the bluff on the opposite side of- the river is a pyritous sandy lime- 

 stone very like that which is at the base of the Knox group. A similar 

 condition was observed in crossing Buckner's ridge along the Jonesville 

 and Estillville road, at probably fourteen miles west from Stony creek. 



Copper ridge lies on the southerly side of Clinch river, until within 

 six miles of the Tennessee line, where it is crossed by that river. It is 

 a monoclina], but the dip is irregular, as is shown along the Stony creek 

 road as well as along the road leading from Gray's ford on Clinch river to 

 Nickelsville on the southerly slope of the ridge. The dip at Clinch 

 river is not far from 40 degrees ; at two miles from the river, the beds are 

 almost horizontal ; but toward the southerly side of the ridge, the dip in- 

 creases to almost 33 degrees. The only rocks exposed in this ridge belong 

 to the Lower Silurian groups. Prof Lesley, on the map accompanying his 

 memoir on Wise and Tazewell counties, colors Clinton along the southerly 

 side of this ridge; but no Clinton is present within Scott county.* The 

 structure of the ridge in this county suggests the possibility that, at no 

 great distance eastward, the ridge may consist of a double anticlinal with 

 a shallow synclinal along the crest, in which some Upper Silurian rocks 

 may be held. 



The Copper Creek Fault, as appears from Prof. Lesley's map, extends 

 for a considerable distance into Russell county, which adjoins Scott on the 

 north-east. It was examined by the writer very near the Russell county 



*Prof. Lesley did not visit this portion of Scott county. 



