WITH ANTICLINAL AXES AND FAULTS. 341 



Of the mechanical and chemical agencies concerned in the pro- 

 duction of some of these thermal springs, I have already briefly- 

 expressed my views, while describing the structure of the Warm 

 Spring Valley, rnd its enclosing movmtains ; and I need hardly 

 add, that the same general explanation is equally applicable to 

 the other thermals, situated in anticlinal valleys. In carrying out 

 this view more in detail, and especially in applying it to cases 

 like that of the Sweet Spring Valley, where the anticlinal axis 

 passes into a prolonged line of fault, it has appeared to me to be 

 necessary as well as reasonable to admit, prst^ that the subterra- 

 nean channels, which operate both in furnishing the requisite 

 supplies of water and air to the depths belou", and in forwarding 

 the thermal stream under hydrostatic pressure, must have a direc- 

 tion conforming in general to the strike of the rocks ; and, sec- 

 ondly^ that the direction of the downward flow of the meteoric 

 waters, is in a great degree determined by the natm-al partings of 

 the strata, or, in other words, by the plane of dip. 



These conditions granted, it will at once appear, that in a 

 closed anticlinal valley, like that of the warm and liot springs, 

 thermals, if occurring at all, might be expected to appear along 

 its whole length, in a linear arrangement, and near its western 

 boundary. It would also seem, in this case, that the height of 

 the comparatively elevated gi-ound at the two ends of the valley 

 would determine the hydrostatic column employed in bringing 

 the Avater to the surface. 



Where, however, the valley is closed only at one end, as in 

 that of the Sweet Springs, the case is, I think, different. Ther- 

 mals may of course be looked for towards the closed end, and in 

 this position they are found ; but it is a remarkable fact, that the 

 line of fault constituting the prolongation of the axis of the Sweet 

 Springs, though continued to a distance of more than fifty miles, 

 does not disclose a single thermal throughout its whole extent, 

 nor have I yet succeeded in discovering more than one spring 

 of the kind, in other parts of the Appalachian chain, where simi- 

 lar geological conditions prevail. On the other hand, in the pro- 

 longed line of fault running along the southeastern base of the 

 Little North Mountain, close to the northwestern margin of our 



