1881.1 Z^O [Stevenson. 



and the mountain to Powell mountain. There the ridge is narrow ; hut at 

 some miles further west the conditions are as in Fig. 3, whicli shows the 

 section from the Poor Valley fault on North Fork of Powell to the Wallen 

 Valley fault near Stickleyville. Here instead of the single ridge seen at 

 the Turkey Cove there are three ridges, known as Chestnut ridge. Elk 

 Knob and Wallen's ridge. The folds in Chestnut ridge are exceedingly 

 complex, and are well shown in the gap by which the Nortli Fork of 

 Powell river passes through it. The beds are folded without crushing, 

 though some of the angles are as sharp and close as the bent elbow. But 

 In Elk Knob the strata are practically horizontal until near the southerly 

 slope where the dip becomes nearly 15 degrees. The rate increases toward 

 Wallen's ridge as well as in the ridge, until, along the summit line, the 

 Medina dips at nearly 40 degrees. The UiDper Silurian rocks are reached 

 on the southerly slope of the ridge. 



The relations of Wallen's ridge to Powell mountain are somewhat com- 

 plicated by the Wallen Valley fault, which begins at the head of Wallen's 

 valley. As far as could be ascertained, no traces of that fault exist fui'ther 

 east. That part of Powell mountain which lies east from Slemp's gap, 

 through which the North Fork of Clinch flows, has a very different struc- 

 ture from that of the part lying west from that gap. The eastern division 

 is but a continuation of Wallen's ridge, the separation being due solely to 

 erosion ; for, on the bold bluff which Powell mountain presents to the 

 valleys of the South Fork of Powell river and the North Fork of Clinch 

 river, the section is but a continuation of that shown on the slope of 

 Wallen ridge ; and the Lower Helderberg, Oriskany, Hamilton, Lower Car- 

 boniferous and Quinnimont group appear in regular succession, while the 

 Quinnimont group covers the southerly slope of the mountain to where it 

 is cut off by the Hunter Valley fault. The conditions observed on this 

 side of Powell mountain will be described in connection with that fault. 



The Wallen Valley fault begins at the head of that valley, and continues 

 into Tennessee. It passes along the southerly side of Wallen's ridge, and 

 is crossed by the Jonesville and Estillville road at, say, nearly half a mile 

 from Wallen's creek. On its northerly side are the Lower Helderberg 

 rocks, ill-exposed where examined, dipping almost south-east at 45 degrees, 

 while the limestones of Formation III are shown on the southerly side dip- 

 ping in the same direction at 30 degrees. The upper part of No. II is 

 shown near the fault, but only a small part of that group is brought up 

 where the examinations were made. It is not wholly certain that tbis 

 fault begins within Wallen's valley, but no traces of it were seen on the 

 other side of the mountain, where, however, the forest is dense, and expo- 

 sures are few and not satisfactory. It is certainly absent from the valley of 

 North Fork of Clinch at three miles further up. This fault is important 

 economicallj'', for, in great measure owing to its sudden development, 

 Powell mountain west from Slemp's gap has been so far elevated that the 

 Devonian, Lower Carboniferous and Qaiunimoni group, still present on 

 the other division of the mountain, have been wholly removed by erosion. 



