1881.] -^4:7 [Stevenson. 



On emerging from the gap made through this low ridge, the stream 

 enters the North Fork, which there changes its course, and for a short dis- 

 tance flows irregularly along the strike. The road follows the right bank 

 of the stream, and winds so as to be now in the Lower Helderberg, then in 

 the Hamilton shales. The upper limestone of the Lower Helderberg is 

 "well exposed at the roadside, not far below the gap, where it underlies the 

 Oriskany, which is ferriferous. The river changes its course near Mr. James 

 Rohinet's place, and breaks across the Hunter Valley fault (Clinch River 

 uplift), whose course is marked by Buckner's ridge. The Hamilton shales 

 are fairly well exposed here and are dark throughout. Those resting on 

 the Oriskany are richly carbonaceous, and films of coal are common in one 

 layer, which is nearly 18 inches thick. 



No rocks newer than the Hamilton shales are shown between the crest 

 of Powell mountain and Buckner's ridge, as far, at least, as two miles west 

 from the North Fork gap in the latter ridge. If the Pattonsville fault were 

 absent, there would be ample room for the Lower Carboniferous groups, 

 which, indeed, are present on Powell mountain in the other division of 

 this area. A material change in the character of this fault must take place 

 at not far from the gap, for Prof. Safford's map shows that the Lower Car- 

 boniferous groups are present at the State line both on the slope of Powell 

 mountain, and on the ridge marked by the Pattonsville fault. 



The gap of North Pork of Clinch exhibits the complicated structure of 

 the Hunter Valley fault or Clinch River uplift. The pyritous calcareous 

 sandstouHs, belonging to the base of the Knox group, form a bold ridge 

 with the rocks dipping southward at almost 50 degrees ; but at the base of 

 the cliff on the northerly side, a considerable mass of limestones, reddish 

 and white sandstones was seen. This is not less than 150 feet thick. Be- 

 hind it is an imperfectly exposed interval between the base of this bluff 

 and the last exposure of Hamilton shale, in which are fragments of sand- 

 stone not unlike the Oriskany. This mass is covered with debris and the 

 succession of its beds could not be made out. Unsuccessful search w^as 

 made for fossils. A conglomerate of rounded quartz pebbles bound by red 

 hematite occurs here, and bears much resemblance to the Clinton ore ; 

 with it is a ferruginous sandstone, which, when casually examined, appears 

 to be an iron ore. It is, however, merely a very fine-grained ferruginous 

 sandstone. This is shown on both sides of the gap, and the apparent 

 amount of ore is very great. But the material is utterly worthless as ap- 

 pears from Mr. MrCreath's analyses ; No. 1 being the conglomerate, and 

 No. 2 the ferruginous sandstone. 



Metallic iron 12.050 11.550 



Sulphur 0.052 



Phosphorus 0.862 



Insoluble residue 69.400 



This was worked many j^ears ago in a forge, whose ruins still remain in 

 the gap. 

 Returning now to the Jonesville and Estillville road, one finds the Lower 



