M, B. Studer on the Oriyin of Granite* 305 



metamorphosis which the Alps present, and, at the same time, 

 one of those which most decidedly proves that these phenomena 

 are of recent origin in the Alps, since a part of the rocks 

 which exhibit them rest upon the nummulitic system." Now 

 that the theory of elevation has become so universally popu- 

 lar, the principle of metamorphosis, which is so closely con- 

 nected with it, finds many supporters, especially among those 

 geologists who have had frequent opportunities of studying the 

 slaty crystalline rocks. Keilhau, in the years 1836 and 1837, 

 pointed out many remarkable and extraordinary facts observed 

 in the neighbourhood of Christiania, which likewise go far be- 

 yond the reach of the present state of chemistry ; although they 

 refer more to the consequences of immediate contact than to 

 those changes which are produced upon the great scale. It, 

 moreover, would perhaps have been desirable that Keilhau 

 should not have been so minute in his explanations, because 

 the learned world is very apt to throw away, with a theory 

 which it may deem untenable, the facts which are intended to 

 elucidate that theory. The views, also, which M. Elie de Beau- 

 mont advanced in 1828, regarding the metamorphosis of the 

 secondary rocks of the Tarentaise into cipoUn-Umestones and 

 crystalline slates, have produced a very considerable effect. * 

 As in the Alps, so in the Pyrenees, the principle of meta- 

 morphosis was to M. Dufrenoy a strong point of support in 

 the explanation of the most important relations and now 

 scarcely a year passes over our heads, during which, in moun- 

 tains and districts which had not previously been examined, 

 or, at all events, in relation to this point, new support to our 

 theory is not procured. In Italy, the practical geologists Sis- 

 monda, Pareto, Guidoni, and Savi, have become converts to 

 the new belief ; and the last-named individual, in his latest 

 writings, shews himself much inclined to suppose that serpen- 



* From that time especially has the spell been broken, which, from the 

 earliest date, induced the belief that the highest Alps were to be considered 

 as the first-bom of the earth's formations ; and, witli this notipn, has Uio 

 opinion vanished, that, from the appearance of a rock itself, the epoch of its 

 formation may be determined. 



