1.S81.] ZJ-J.J [Stevenson. 



tance, the Hamilton shales are the lowest beds exposed on the northerly 

 side of the fault, while at several localities lower groups, even down to the 

 Medina, have been brought up. 



At the gap of North Fork of Clinch, the Hamilton shales are well ex- 

 posed on the northerly side at some distance from the line of break, where 

 they are abnormally thick, show a strike N. 80° E. mag. and are dipping 

 toward the fault at 40 degrees. Some sandstones seen between these and 

 the foot of Buckner's ridge may represent the Lower Helderberg, and the 

 Clinton rocks are exposed at the foot of the ridge. Whether or not the 

 succession is complete, was not determined, as the side of the ridge is 

 deeply covered with debris ; but fragments of quartzite-like white sand- 

 stone were seen, which bear mucli resemblance to tlie Medina sandstone as 

 shown in Moccasin gap of Clinch mountain. The exposures are all poor 

 and the Clinton was recognized only by its fossil ore. The probable struc- 

 ture is doubtless as represented in Fig. 5. 



6 



f 

 Fig. 5.— Probable structure of Hunter Valley fault at North Fork gap. /, Hun- 

 ter Valley fault. Numbers as in Fig. 1. 



The fault is crossed by the Jonesville and Estillville road at two or three 

 miles further east. Tliere the Hamilton shales, shown in the river " bot- 

 tom," appear to be in contact with the calcareous sandstones of the Knox 

 group, which form a bold wall along the line of fault. These shales are 

 dipping toward the fault, but they may be folded as they are near the North 

 Fork gap. At four or five miles further east, one has passed bej^ond the 

 influence of the Pattonsville and Wallen Valley faults, and has reached the 

 southerly foot of Powell mountain in Hunter valley. Standing here at the 

 railroad line, he can follow with his eye, the course of the fault in each 

 direction, for it is marked by the low and sharply serrate ridge known as 

 Buckner's ridge. This seems to follow an almost straight line from the 

 county line to the North Fork gap. 



In the Hunter valley, the wall of Knox sandstone is as well marked as it 

 is along the North Fork of Clinch, while on the other side the Qainnimont 

 group covers the slope of Powell mountain and extends into the ralley. 

 Near the end of the valley, the North Gap structure is repeated, but only 

 the Lower Carboniferous and the Devonian are turned up. Beyond this, 

 no exposures exhibiting the structure were seen until Stony creek was ap- 

 proached. The sandstone wall is distinct all the way, but the debris from 

 the conglomerates covers the whole "bottom " deeply even to the foot of 

 the wall. Toward Stony creek, the structure becomes verj-- similar to that 

 observed in the North Fork gap, but time did not admit of working out its 

 details. The Lower Carboniferous, the Devonian and the Silurian as far 

 down as the Clinton at least, were recognized on Stony creek between the 

 last exposure of the Quinnimont series and the wall of Knox sandstone. 



