Volcanos and Earthquakes, 377 



Valleys of elevation of the kind described seem to be of 

 tolerably frequent occurrence ; thermal springs and disengage- 

 ments of carbonic acid gas are not, however, always met with, 

 either for want of sufficient depth of the clefts, or for want of 

 materials which give rise to the disengagement of carbonic acid 

 gas. Instances of three of such valleys at the eastern end of 

 the basin of London^ are given by Buckland.* See also his 

 and Conybeare's-(- description of the structure of the country 

 al St Vincent's rocks ; and the example at Matlock long ago 

 pointed out by Whitehurst.J Many other instances of this 

 kind occur in Daubeny'*s report. || Stifft§ also has long ago 

 shewn, that the rocks in the neighbourhood of the mineral 

 springs of the Nassau territory manifest evident changes in the 

 direction and inclination of their strata, especially saddle-shaped 

 elevations, often accompanied with fractures. 



Finally, dislocations or faults produced by elevations and in- 

 tersecting stratified rocks, may direct the subterranean course 

 of springs in a very different manner. Buckland^ has given 

 many instances of springs originating from causes of this 

 kind. 



If we take a summary view of all that has been said on the 

 subject of thermal springs, we shall find it impossible to avoid 

 recognising a relation between elevations of Plutonic masses, 

 the upraising of Neptunian formations, and thermal springs. 

 Cause and effect have, however, been frequently confounded 

 here. Thermal and mineral springs are seldom, perhaps never, 

 the cause of those effects. Where, however, these effects are 

 observed, where, in consequence, the penetration of meteoric 

 water into the interior of our earth has been rendered possible^ 

 and where natural hydraulic tubes have been formed by the 

 upraising of strata, there the phenomena of thermal and mineral 

 springs were the consequence. 



We should transgress our limits, were we here to pursue the 

 subject of thermal springs in their chemical relations, since the 



* Geological Transact sec. ser. vol. ii. part i. p. 119. t Ibid. vol. i. 



X Theory of the Earth, 1786. II P. 66. 



§ Rullmann Wiesbaden, &c. 1823, p. 103. 



H Geology and Mineralogy, &c. London 1836. Vol. ii. p. 106 and HO. 



VOL. XXVI. NO. LII, APRIL 1839. B b^ 



