101 



The sandstones, limestones, and slates of this region, are all of 

 them convertible to useful purposes. The pinkish variety of the 

 former is quarried in the North mountain to furnish hearths for fur- 

 naces, and has a hardness and sharp grit, which has led to its em- 

 ployment as a substitute for the more expensive millstones. The 

 slate is largely impregnated with iron pyrites, and upon exposure to 

 the air yields a great quantity of sulphate of iron or copperas, as well 

 as sulphate of alumina or alum. It is for this reason, that the springs 

 of this part of the state so frequently possess a sulphuretted, chaly- 

 beate, and acid character, and that some of them are so powerfully 

 remedial in cutaneous and various other diseases. The celebrated 

 alum rock on Jackson's river, consists of nothing but this slate, 

 which here rises in an abrupt and lofty cliff, forming a semi-circle at 

 the bend of the river, and presenting a scene which is at once curi- 

 ous and imposing. Over the surface of the wall-like precipice, 

 streaks and stains arising from the copperas or ferruginous matter 

 of the rock, may everywhere be seen, and large nodules of a 

 spheroidal form, and of the size of a bomb, lie here and there em- 

 bedded in the mass. Such is the amount of chalybeate and other 

 saline, as well as sulphureous matter in these slates, that the inhabi- 

 tants of the country, in lieu of resorting to the springs, of which 

 some, as the Alum spring, are much in vogue, are accustomed to 

 make use of the detached fragments of the rock, which in small 

 quantity will impart to water all the flavour and effects of the springs 

 themselves. 



Chalybeate and sulphuretted springs break forth in various 

 places from the pyritous slate above described, many of which, as 

 for example, the Botetourt, Augusta, Rawley, Shannondale, Yellow, 

 and Alum springs, have acquired reputation for their medicinal vir- 

 tues. Thermal waters abounding in free carbonic acid and nitrogen 

 gases, resembling those of the Warm spring valley, occur in some 

 localities, an interesting example of which may be seen in the neigh- 

 bourhood of Kaiser's, in the gorge of the Rich Patch mountain. 

 Analyses now on foot in relation to the characters of several of 

 those waters, forbid the publication at present of any decisive re- 

 sults, but it is hoped, that by an early day some account of their 

 constitution will be embodied in a treatise on the mineral waters of 

 Virginia, now in course of preparation. 



Of the limestone, it may be merely stated, that it is capable of fur- 



