88 



the rocks of one side of the globe, in those of the other, and will, 

 therefore, prefer a description of the object itself to any appellation 

 to which, from its supposed resemblances, it might be thought en- 

 titled. 



From the list above given, it will at once appear, that, there is no 

 material difference between the rocks of the Blue Ridge and those of 

 the South-west mountain and the intervening country, and that 

 they seem in the main to be distinctly referable to a sedimentary 

 origin. 



From the above view of the general structure of the ridge, we may 

 derive a suggestion of some importance in connexion with plans of 

 internal improvement projected in the state, which is, that the dense 

 and impracticable character of many of the rocks above described, — 

 for instance, those from six to twelve, — forbids any attempt at tun- 

 nelling the mountain, at least in those places which have been ex- 

 amined, and evinces the necessity, whenever such a plan shall be 

 proposed in reference to other parts of the ridge, of first ascertaining 

 whether it does not there also include near its axis materials equally 

 unfavourable to operations of this kind. 



The soils of the region from the Blue Ridge, east as far as the 

 limestone, are in many places of a deep red or chocolate colour, 

 while in others they present either a grayish or yellowish hue. 

 Those of the former kind are usually regarded as most fertile, and 

 chiefly give value to the lands of Albemarle, Amherst, and other 

 counties in this part of the state. In accounting for these striking 

 peculiarities of colour and agricultural properties of the soils in 

 question, it has been usual to regard them as resulting from the 

 hornblende, frequently met with in the rocks of this region, which 

 by its iron would give colour, and by its lime impart fertility, to the 

 land. There is, however, but a small portion of this deeply coloured 

 soil traceable to a decomposing rock of the description mentioned, 

 and by far the largest part of the land thus tinged had been produced 

 by the disintegration of the dark greenish-blue sandstone, such as 

 occurs so abundantly in the South-west mountain. Much of the 

 richest and darkest red soil of Amherst and Albemarle has no horn- 

 blende in its neighbourhood, while beneath and mingled with the 

 soil, fragments of the sandstone above referred to, may be seen in 

 all the gradations of condition, from the hard greenish rock recently 

 separated from the mass, to the crumbling half-earthy and deeply 



