Sewell Mountains. — Valley of the Greenbrier. 93 



while the other rocks are found in order as you ascend or descend 

 the sides of the mountain ridges, which, in these ranges, are very- 

 abrupt and narrow. In descending the Sewell mountain into the 

 valley, we pass different colored clay slate, grey, yellowish and ash 

 colored sandstone rocks to the base. Coal is also found in its proper 

 place amidst the other strata in the sides of the mountain, which 

 dip in proportion to the rapidity of the rise of the range. About 

 ten miles south of the foot of the Sewell mountains, a very striking 

 change is observed in the character of the surface strata. The 

 sandstone rocks disappear and a dark calcareous deposit takes its 

 place. The hne of demarcation is so well defined that large frag- 

 ments are sometimes seen, one part of which is limestone and the 

 other part sandstone. The valley of the Greenbrier is from thirty 

 to forty miles wide at its S. W. extremity, where it rests on the 

 New river, narrowing gradually to a point, as the ranges of the Al- 

 leghany and the Greenbrier mountains approach each other at the 

 heads of the Greenbrier river, a distance of one hundred miles. 

 A thick deposit of calcareous rock covers the whole of this valley, 

 reposing on sandstone, which appears at many places on the sides 

 and tops of hills, into which the valley -is broken, in abrupt cliffs, 

 evidently showing the more recent formation of the limestone stra- 

 tum, over and amongst the sandstone deposits. The whole valley 

 abounds in extensive caverns, cut out of the limestone, from the 

 dissolution and wearing away of the rock, by the agency of water, 

 all the caves having streams running in some part of them, or bear- 

 ing evident marks of the course of former currents. Some of these 



O 



caverns abound in saltpetre earth, and contain fossil bones. The 

 bones of the megalonyx, described by Mr. Jefferson, were found in 

 a saltpetre cave in this valley. " Sink holes" are numerous, into 

 which the surface water discharges itself and finds hs way under 

 ground to the river, or rises again in some other place below : as the 

 whole valley has a rapid descent to the S. W. which is proved by 

 the numerous falls and rapids in the bed of the Greenbrier river. 

 This stream is about one hundred yards wide at its mouth, and has 

 a descent of more than six hundred feet, from its head at the base of 

 the Cheat and Greenbrier mountains, to its junction with the New 

 river ; that point, being thirteen hundred and twenty five feet above 

 the ocean, and its heads more than two thousand. The calcareous 

 soil of the valley, combined with decomposed vegetable matter, is 

 well suited to cultivation, and many fine wheat and grazing farms 



