m 



different places. Of the lead ore, gypsum, &,c. of the south-west, we 

 will speak hereafter. 



The numerous extensive caves occurring in this region, form one 

 of its most curious and interesting features, and serve to illustrate 

 some of those geological and chemical agencies to which allusion has 

 been made in explaining certain facts connected with formations in 

 other parts of the state. Thus, in the rich and variegated crystal- 

 line deposites and concretions, which render some of the caves ob- 

 jects of so much curiosity to the visiter — the solvent action of water 

 upon the various kinds of rocks composed of carbonate of lime, and 

 the ready tendency of the dissolved matter to separate in a pure and 

 crystallized condition, are both beautifully displayed, while the round- 

 ed surfaces of the rocks within the caves, and the generally curved 

 contour of the various apartments, give evidence of the wearing, as 

 well as the dissolving energy of subterranean streams. Usually 

 some disturbance of the rocky strata will be seen in and around 

 these caves ; and in the various fissures and deep clefts naturally 

 accompanying such dislocations of the strata, we are furnished with 

 a ready explanation of the means by which the agent that has thus 

 scooped them out, originally obtained access to the surface of the 

 rock. 



OP THE NORTH MOUNTAIN AND ALLEGHANY REGION. 



The numerous ranges of mountains which lie beyond the general 

 limits of the valley, present several features of great practical, as 

 well as scientific interest. In the profile view, a section of the Lit- 

 tle North mountain, as presented west of Mossy creek in Rocking- 

 ham, terminates the line of observation first examined ; and the pro- 

 file is resumed at a point farther south, in a direction from Coving- 

 ton across the Great North mountain into Rockbridge. The lesser 

 ranges of mountains which first interrupt the general undulating sur- 

 face of the valley, known by the various names of Little North 

 mountain, Catawba mountain, &c, indicate the commencement of a 

 series of rocks entirely distinct from those occurring in the valley, 

 being composed of sandstones and conglomerates, and of shales 

 subordinate to the veins of anthracite and semi-bituminous coal, 

 which here discover themselves. The dip of these, so far as ob- 

 served during the reconnoissance, is somewhat steeply west, as re- 



