1884.] l'»l [Stevenson. 



on the tributary to Guest's river crossed by the Wheeler Ford road ; but it 

 is crossed by the Osborn's ford and Guest's Station road at little more than 

 a mile from Guest's river ; further westward it passes between Hish Knob 

 and Little Stone gap. The anticlinal can be traced thence to the Tennessee 

 line, the axis Ij'ing close to Stone or Cumberland mountain. 



The fold is utterlj^ insignificant on Russell and Bull creeks, biit becomes 

 well-marked on Guest's river. It is crossed by the Middle Coal measures 

 on the former streams, but the Lower Coal measures are brought up in 

 the gorge of Guest's river. Thence westward, the increase in strength is 

 rapid and the Lower Coal measures are raised quickly to form the Powell- 

 Stone mountain lying between Buckner's ridge and the valley of Butcher's 

 or South fork of Powell river. The dip on the southerly side is gentle 

 throughout, but soon becomes abrupt on the northerly side — at Guest's 

 river it is from 5 to 7 degrees, but at Little Stone gap the rocks are al- 

 most vertical and so remain to beyond Pennington's gap in Lee county. 



Three well-defined faults, described in the writer's previous memoir as 

 the Pattonsville, Wallens Valley and Poor Valley, develop on the souther- 

 ly side of this fold and cut off abruptly the clumsy Powell-Stone mountain. 

 The Carboniferous rocks have a curved outcrop at the westerly end of 

 that mountain, while in Powell mountain beyond North fork of Clinch 

 river, in Wallens ridge and in the broad vallej'^ of Powell river, the De- 

 vonian, Silurian and Cambro-Silurian are exhibited. From Big Stone gap 

 in Wise county the area affected by the fold embraces only the precipitous 

 Stone mountain and a very narrow space directly adjoining it on the south- 

 east. The fold from Little Stone gap to the State line is so abrupt as to 

 resemble a fault ; its trend is at an acute angle with the lines of faulting. 



Vertical Extent of the Faults. 



The following table shows approximately the vertical extent of the 

 several faults — the extremes only being given. 



Clinch 8500 to 1000 



New Garden 7500 to 6G00 



Stony ridge 2300 to ? ? 



Abb's valley 1700 to ? ? 



Saltville 10000 to 7000 



Walker mountain 7500 to 3000 



IL THE GEOLOGICAL GROUPS. 



Benches and terraces, beautifully preserved, were seen at many places, 

 but the time allotted to this reconnaissance left few opportunities for mak- 

 ing measurements of altitudes. Clinch river is bordered for the most part 

 bj^ high hills, so that in order to secure available grades, wagon roads 

 usually follow the gorges of tributary streams. For this reason, the 

 existence of terraces is concealed from the traveler until the river is 

 reached. But where, as in a few cases, the road descends directly from 



