Natural Histofy of Volcanos and Earthquakes. 61 



versa, veins of very dissimilar local origin may issue very near 

 one another. Nothing is therefore easier to conceive, than that 

 any stratum in which the materials requisite for the forma- 

 tion of sulphureous springs at present, may be traversed by 

 springs arising from very various depths, and therefore possess- 

 ing very unusual temperatures, which circumstance would give 

 rise to sprmgs of similar chemical composition, but dissimilar 

 temperature. 



■Forbes* remarks that the hot springs at Baden-Baden, on the 

 border of the Schwarlzwald, have a position almost identical 

 with that which we have so invariably remarked in the Pyre- 

 nees. They occur just where the slate rocks have been violently 

 upraised by a curious granitoidal porphyry, which forms the pic^ 

 turesque elevations near the Alte iSchloss, and which passes 

 into a true granite. Upon the slate, red sandstone lies uncon- 

 formably. The elevation is among the older of M. Elie de 

 Beaumont's systems : he expressly states that the Gres bigarre 

 is undisturbed. 



Relative to the thermal springs in the Pennine Alps, Bake- 

 wellf remarks, that, according to his observations, the exits of all 

 of them lie partly in the primitive mountains of the central chain 

 itself, partly, and indeed most frequently, at their extremities, at 

 the boundary between the primitive mountains and the second- 

 ary formations. 



According to the beautiful investigations of De Beaumont, two 

 different systems are to be distinguished in the Alps, viz., that 

 of the Western Alps, and that of the principal chain from the 

 Valais to Austria. Mont Blanc lies at the point of intersection 

 of these two systems, which here meet at an angle of 45°-50° ; 

 also Leuk. The period of elevation of these two systems falls 

 somewhat late. That of the strata belonging to the first system 

 took place after the deposition of the newest tertiary formations 

 of these regions, and that of the strata belonging to the second 

 system between the deposition of the earlier diluvium {des altes- 

 ten aufgeschwemmten handes) and the flowing of the diluvial 

 streams, and at the time of the transport of the erratic Alpine 

 rocks. The most favorable conditions for the origin of thermal 

 springs evidently exist when the upraising, caused by the masses 



* L. c, p. 609. t Philos. Magazine, January, 1328, p. 14. 



