Volcanos and Earthquakes, 365 



has been formed, which receives the meteoric water flpwing 

 down on that side of the elevated mountain C, which lies next 

 to the raised strata. The meteoric water which flows down 

 through the newest fissured stratum, will now as little give origin 

 to rising springs as during its earlier horizontal position. If, 

 now, after the period of this elevation, a stratum of a new for- 

 mation should occur covering the extremities of the older raised 

 strata, and extending from B to D, and if, lastly, the new forma- 

 tion contain impervious strata, then the conditions will undergo 

 a change. The meteoric water, which penetrates at A, between 

 each separate portion, will now all issue in the form of rising 

 springs at B, between the elevated mountain and the new stra- 

 tified formation which lies at its side. Should any obstacle here 

 present itself to its exit, the water will even take a retrograde 

 course B D, and issue at D, in which case the water between 

 the last formed horizontal stratum and the impervious stratum 

 lying under the newest raised ones will unite with it. We will 

 not, however, enter into farther particulars, as many circum- 

 stances may be supposed to exist which modify the course of 

 the springs ; and still more complicated relations naturally 

 arise when, after the deposition of the latest formed stratum, 

 the elevation and raising are repeated. It will be sufficient to 

 have called attention to the circumstance, that rising springs 

 can only exist when the originally horizontal position of the 

 stratified formations has been destroyed by elevations ; and that 

 the most copious springs and those which arise from the great- 

 est depths are found precisely at the limits between the elevated 

 masses and the raised strata. 



Numerous instances can be cited in proof of this assertion. 

 The Pyrenees and Alps present very characteristic circum- 

 stances. Thus Pallasou* shews, that not only are the majority 

 of the hot springs in the Pyrenees^ situated in the great gra- 

 nitic district at the eastern side, but also that all the others issue 

 only from hollows of the newer formations, where the granite 

 rises from beneath, at the foot of the declivities. He shews 

 also, that even the degree of temperature of these springs de- 

 pends on the greater or less exposure of their source ; for the 



M^m. pour servir k I'Hist. Natur. des Pyr^n^es, 1815, p. 435, 459. 



