WITH ANTICLINAL AXES AND FAULTS. 347 



ticularly deserving of attention. I mean, the almost entire ab- 

 sence, over its vast surface, of igneous or volcanic rocks. These 

 occur at only four or five points, without any observable relation 

 to axes, and away from the neighborhood of any known thermals, 

 and are in such small amount as together not to cover an area of 

 more than ten acres. Add to the preceding this further fact, that 

 our thermals are not confined to particular lines or axes, but are 

 scattered at remote points over the whole region, and it w411 at 

 once appear, with how much more reason they may be referred 

 to a pervasive subterranean heat, than to points or lines of vol- 

 canic action. To apply the latter explanation, we must give to 

 these local foci a diffusion beneath the surface, which would, in 

 fact, amount to abandoning the doctrine of merely local heating 

 action, and admitting that of a general internal heat ; while, in 

 adopting this latter, we see, in the peculiar positions of our ther- 

 mals in reference to axes, simply those mechanical conditions 

 IV hie h favor the access of air and water to the deep-seated, and 

 therefore hot strata in the interior, and their expulsion at the 

 surface. 



Adopting the language used by the eminently philosophic 

 Phillips, when referring to arguments urged in favor of the hy- 

 pothesis of local volcanic action, as the cause of thermal springs 

 in general, I would say, " These arguments, when taken in con- 

 nection, appear to us to prove, that the heat of the springs is de- 

 rived from the depths of the channels in which they flow below 

 the surface," and "it seems unnecessary to appeal to local vol- 

 canic excitement for an effect which spreads, both in time and 

 area, far beyond the traces of purely volcanic phenomena." Such 

 being the inferences of one of the ablest of geologists, from a 

 comparison of the chemical and geological relations of the ther- 

 mals of the old world, with what augmented force may they not be 

 reiterated, after the preceding developement of these relations in 

 a region which, like our Appalachian chain, is almost destitute 

 of even a trace of proper volcanic action ! 



