Natural History of Volcanos and Earthquakes. 



57 



springs can be supposed to exist in the whole of this district, and 

 the inhabitants of such mountains could only supply their want 

 of water by wells (Senkbrunnen.) We will now suppose, that 

 at two points of this district, volcanic masses are thrown up, and 

 that, in consequence, a partial elevation of the strata takes place, 

 as is shown in the diagram, fig. 1. In this case, the hydrographic 

 relations undergo considerable alterations. The consequence 

 will be not only a movement of the water on the impervious 

 stratum, in the direction of its inclination, but meteoric water 

 will also penetrate at A between the older strata, where, during 

 their undisturbed horizontal position, not a drop of water could 

 penetrate, and this water will continue to flow in the direction of 

 the inclination of the elevated strata.* At B, where these strata 



Fig. 1. 



are also elevated, but to a lower level, springs will commence ris- 

 ing ; and as many of such springs may be supposed to exist in a 

 district, as there are alternations of impervious and pervious strata 

 in these mountains. The most copious springs, however, will be 

 found between the mass that has been broken through, and the 

 oldest formation of the stratified mountain, because here, in con- 

 sequence of the contraction of the former mass during its cooling, 

 a cleft has been formed, which receives the meteoric water flow- 

 ing 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 ori- 

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

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

 tion should occur, coverino; the extremities of the older raised 



* The same holds good with regard to the springs of fresh water Thus on the 

 Schwaliisch Alp springs are always found ihere where cones of hasalt or basal- 

 tic tufa have been elevated on the jura-formation. Plieninger in PoggendorfF's 

 Annal. t xl, p 493. 



Vol. xxxvii, No. 1.— July, 1839, bis. 8 



