GEOLOGICAL SOCIETY OF PENNSYLVANIA. 331 



tents most rapidly when they are in quick motion and at 

 shallow depths, the water being then more completely 

 submitted to the action of the sun, and rendered less 

 capable of holding the calcareous matter in solution. 

 This I suppose to be the cause of the broad calcareous 

 slope which has been attributed to the ingenuity of the 

 beavers. When these valleys of denudation were scooped 

 out, and a deep ravine formed where this rich valley 

 bottom now is, the stream at this place probably passed 

 over a rapid, that breaking the water produced the de- 

 posit in question, which constantly rose in height until 

 the aqueous volume diminished to its present size, by the 

 filling up of the ravine with calcareous and vegetable 

 alluvial matter, converting the bare slaty bed of the ra- 

 vine into a fertile valley, capable of producing 10,000 

 bushels of Indian corn annually; a singular instance of 

 the beneficent manner in which nature operates in favour 

 of man. For here we see the springs of life not only 

 issuing from the depths of the wilderness to restore the 

 enfeebled constitution of the sufTering southerner, but 

 that portion of them not directly applicable to his wants, 

 mechanically engaged, by a most happy process, in pro- 

 ducing the means of sustaining those who here seek relief, 

 and of embellishing every thing around them. These 

 are amongst the charming lessons we receive from nature, 

 and which dispose our hearts to see a divine care for us 

 in every thing. 



The following section exhibits the course of the stream. 



CL b 



c 



I 

 I 



I 



I 



a The Sweet Springs, b Fall, supposed a beaver dam. c Cascade. 



I was one day returning to my cabin, with some speci- 

 mens of this travertin, when I met Mr Rogers, the land- 



