Description of a Natural Tunnel, 351 



its floor. The width of the tunnel varies from fifty to one hundred 

 and fifty feet ; its course is that of a continuous curve, resembling 

 the letter S, first winding to the right as we enter on the upper 

 side, then to the left, again to the right, and then again to the 

 left, on arriving at the entrance on the lower side. Such is its 

 peculiar form, that an observer, standing at a point about mid- 

 way of its subterranean course, is completely excluded from a 

 view of either entrance, and is left to grope in the dark through 

 a distance of about twenty yards, occupying an intermediate 

 portion of the tunnel. When the sun is near the meridian, and 

 his rays fall upon both entrances, the light reflected from both 

 extremities of the tunnel, contributes to mollify the darkness of 

 this interior portion into a dusky twilight. 



" The extent of the tunnel from its upper to its lower extremity, 

 following its meanders, is about 150 yards, in which distance the 

 stream falls about ten feet, emitting, in its passage over a rocky 

 bed, an agreeable murmur, which is rendered more grateful by 

 its reverberations upon the roof and sides of the grotto. The dis- 

 charge of a musket produces a crash-like report, succeeded by a 

 roar in the tunnel, which has a deafening etfect upon the ear. 



" The hill through which this singular perforation leads, de- 

 scends in a direction from east to west, across the line of the 

 creek, and affords a very convenient passage for a road which 

 traverses it at this place, having a descent in the direction just 

 mentioned, of about four degrees." 



The rocks found in this part of the country are principally 

 sandstone and limestone, in stratifications nearly horizontal, with * 

 occasional beds of clay slate. A mixture of the two former fre- 

 quently occurs among the alternations presented by these rocks. 

 A variety of rock resembling the French burr, occurs in abun- 

 dance on Butcher's fork, of Powell's river, about twenty miles 

 northwardly of the natural tunnel. Fossils are more or less 

 abundant in these and other rocks. Fossil bones of an interesting 

 character have been found in several places. Salt-petre caves 

 are numerous. Coves, sinks, and subterranean caverns are strik- 

 ingly characteristic, not only of the country circumjacent to the 

 natural tunnel, but of the region generally situated between the 

 Cumberland mountain and the Blue ridge or Apalachian moun- 

 tain. Bituminous coal, with its usual accompaniments, abounds 

 in the northerly parts of this region ; and in the intermediate and 



