224 Geology, ^c. of Tennessee, <J/-c. 



inclined. Like the Cumberland, it contains immense rocks of 

 sandstone, but of a coarser grain, verging occasionally into 

 pudding stone. I was told by a white man, a professed mill- 

 wright, that among these sandstone rocks, he knew of many 

 which were suitable for millstones. At the missionary esta- 

 blishment, called " Brainerd," eight miles east of the moun- 

 tain, I saw one of them which was used for this purpose to 

 much advantage. It is composed of fine and large grains of 

 silicious stones, nearly white, and resembling pebbles of white 

 quartz : the texture is firm. 



Silicious Minerals, 4*c. 



1 will now notice an important fact, applicable to the whole 

 extent of limestone country, which has come under my obser- 

 vation. It is its association with a description of minerals, all 

 of which appear to be silicious. To describe them minutely, 

 would require several pages. From the time I entered the 

 limestone country till I left it this association was observed. 

 The minerals included in it differ much in their external 

 character. Their size varies from that of rocks to the smallest 

 fragments. Usually they lie loose upon the earth, in angular 

 forms, having the appearance of a stone that has been broken 

 in pieces by the hammer. Sometimes they cover the sides of 

 hills and mountains in such abundance as to prevent or im- 

 pede vegetation. When the disintegration is minute, they are 

 serviceable rather than otherwise ; and the farmer talks of his 

 " good black," or " white gravel land." It renders this ser- 

 vice, I presume, not by decomposition, but by preventing the 

 soil and its manure from being washed away. Indeed the 

 different varieties of it are generally scattered over the sur- 

 face, in pieces so small, that for convenience sake, the whole 

 may be denominated a silicious gravel. 



Sometimes the mineral is imbedded in limestone, in the 

 form of nodules, thus indicating their original cpnnexion 

 with it. 



