222 &eologyt ^c. of Tennessee, ^c. 



milea, to more than fifty. Its height is not perceptibly differ- 

 ent from that of the Blue Ridge. It forms a circuit, in a shape 

 somewhat resembling a half moon. Winding to the southwest, 

 it keeps a course north of the Tennessee river, in some places 

 nearly parallel with it ; passes a few miles to the southeast 

 of Huntsvillein the Alabama Territory, and not long after ter- 

 minates. At one part, over which I crossed, the mountain is 

 eighteen miles wide. This is about 160 miles southwest of 

 Knoxville, a little north of the 35th degree of N. Lat. I had 

 not ascended the mountain more than half way, before I found 

 sandstone begin to intermingle with limestone strata. As I 

 drew near the summit, the limestone disappeared entirely, and 

 sandstone prevailed in abundance, with no other mineral asso- 

 ciated until I reached the western descent, where I met bold 

 precipices of horizontal limestone, reaching from the base to 

 the summit. I examined several sandstone rocks while cross- 

 ing the mountain, found them usually imbedded in the earth, 

 generally with flat surfaces, of a fine grain, and strong texture. 

 The colour is usually a reddish brown, or grayish red. The 

 specimen which you have received is a good example. I cross- 

 ed this mountain in the vicinity of Huntsville, not less than one 

 hundred miles southwest of the place above-mentioned, and 

 found it not wider than mountains commonly are. Its height 

 had also become less, and horizontal limestone in regular strata 

 prevailed in every part. 



Although this mountain forms a part of the dividing line 

 which has been mentioned, it does not exclusively so : for the 

 Rackoon mountain, which crosses the Tennessee river, at the 

 place so well known by the name of " the Suck," and the 

 Look-Out mountain, which terminates abruptly about 6 miles 

 to the left of " the Suck," form an acute angle with the Cum- 

 berland, and are composed of horizontal strata of limestone. 

 Thus it would appear the line which divides the two kingdoms 

 of this rock, is nearly north and south, inclining perhaps a few 

 points to the east and west. 



