78 



OP THE ROCKS, ORES, SOIL, &C. OP THE REGION WEST OP THE LIMESTONE, 

 AS PAR AS THE WESTERN FLANK OP THE BLUE RIDGE. 



This extensive district of the state comprises a great variety of 

 slates, sandstones, schists and other rocks, almost uniformly dip- 

 ping east, and in general at a very steep angle. Quartz veins are 

 frequently met with, some of which are believed to be auriferous, 

 though as yet, no profitable mine of the precious metal has been 

 opened in them. Beds of trap occasionally occur, the material of 

 which, from its dark colour and extreme hardness, is usually known 

 by the name of iron rock. In some portions of the district, horn- 

 blende enters largely into the composition of many of the rocks, 

 while in others, talc and chlorite appear chiefly to abound. But it 

 is important to remark, that amid all the diversities in the mineral 

 character of the strata, a very general conformability of dip may be 

 observed. Looking merely to the mineralogical constitution of the 

 rocks in many localities, an impression of the undoubted primary 

 character of this district would naturally arise. But when a more 

 general exploration of the region discloses the existence of extensive 

 beds of genuine sandstone, and conglomerate rocks frequently in 

 contact with the former, and having the same uniform inclination, 

 we are unable any longer to maintain this view. This opinion, 

 however, would be found incompatible with the results of a more 

 extensive observation of the rocks, of which this region principally 

 consists. It would then be found, that a large portion of its area is 

 occupied by beds of genuine sandstone and conglomerate rocks, and 

 that the chief part of those strata, which at first view might be re- 

 garded as crystalline and primary in character, are in reality mo- 

 dified forms of sandstones and conglomerates, which, through in- 

 tense igneous action, have been made to assume appearances more 

 or less closely resembling those of rocks of the latter description, 

 thus disguising, almost entirely in some cases, the original sedimen- 

 tary structure by which they would be characterised as not apper- 

 taining to a primary formation. It is the existence of this curious 

 class of rocks in many parts of the region in question, as well as 

 the occurrence of occasional beds in which no appearance of the 

 sedimentary origin can be traced, which imparts to the minute geo- 

 logical investigation of this part of the state, so much of scientific 



