104 



of sandstone of the Warm spring mountain, dipping rather steeply 

 to the east — on the western base of which, we meet with a fossilife- 

 rous limestone, having the same dip, and therefore lying beneath the 

 sandstone. Bounding this valley on the west, the Little Warm spring 

 mountain and its prolongations, exhibit the same rocks in the same re- 

 lative position, with this important difference, that they all dip west. 

 The relation of the rocks thus described, and as they are represented 

 in the section, admits of a simple explanation, by conceiving a violent 

 upthrow to have occurred along the line in which the valley now 

 exists. The sandstones thus thrown off on both sides, left the deep 

 fissure in which the limestones elevated by the same upheaving ac- 

 tion, were revealed to observation. In this view, the mountains 

 bounding the valley have been formed merely by the forcible pro- 

 trusion on either side of beds of sandstone of enormous thickness, 

 which were originally in a horizontal position — and the limestone 

 which appears dipping in opposite directions and beneath the moun- 

 tains, was brought into view by the same agency, although previous 

 to its elevation it must have existed at a depth of nearly 2000 feet 

 below the surface. This valley has, therefore, the character of an 

 enormous fissure, and considering it in that light, we have no diffi- 

 culty in accounting for the number of thermal springs which it con- 

 tains. The well established fact that the temperature of the earth's 

 strata increases with their depth from the surface, in connexion with 

 the structure of the valley here described, will at once explain the 

 elevated temperature which all these springs display, while pecu- 

 liarities in the mineral ingredients of the subjacent beds, ^hiciiit 

 may readily be imagined would account for the gases which they 

 evolve, as well as the saline and other ingredients which they hold 

 dissolved. 



In connexion with these views, it is important to remark, that the 

 fossils and other characters of this limestone distinguish it from 

 those which are found among the mountain chains to the cast or 

 west, and that it bears a striking analogy to the fossil iferous lime- 

 stone formerly described as existing in the great valley of Virginia. 

 Granting the identity of the two, we would thus have the slates and 

 limestones of our valley occupying a position at great depths below 

 the various mountains and valleys we have been describing, and 

 only appearing at the surface where some great uplifting force has 



