326 ON THE IGNEOUS METAMORPHOSIS [Ch. XIV. 



subject, that it is not necessary to make any further remarks : 

 and, therefore, we will turn to those examples which more 

 strongly illustrate the metamorphic hypothesis. The instance 

 quoted by the same author, which occurs at Champoleon in 

 the Alps, is very unsatisfactory in every respect : in the first 

 place, the section does not appear to be natural, and the 

 condition of the strata is not such as might be expected ; we 

 do not detect any of those changes of composition which in- 

 dicate an analogy with the primary rocks ; the argillaceous 

 bed is only hardened, instead of being converted into horn- 

 blende-schist, or even gneiss ; the grits are quartzose, and 

 contain a thin layer of imperfect granite, and all this within 

 a space only of thirty feet from ignited granite, which is 

 capable, according to the theory, of effecting greater changes 

 on beds far removed, and notwithstanding the intervention of 

 an immense mass of bad-conducting substances. It is not 

 impossible that in this case, since the granite at the junction 

 is soft and not perfectly crystalline, it may be a derivative 

 rock, as at Caithness in Scotland, gradually passing into the 

 unaltered and untransported granite : but it is, perhaps, more 

 probable that, as in similar cases, the nature of this rock may 

 have been misunderstood; indeed, Studer has already ob- 

 served that, " les apparences de Predazzo et de Valle Rab- 

 biose, sortent pour ainsi dire de la ligne de celles qu'on peut 

 appeler ordinaires, parce qu'elles se lient aux eruptions du 

 porphyre pyroxenique, et il reste toujours quelque incertitude 

 pour savoir si le granit de Canzacoli n'est positivement 

 qu'une forme particuliere de la roche pyroxenique." * The 

 appearance of the stratified rocks, next the granite of Cham- 

 poleon, is more analogous to that which is exhibited in 

 the vicinity of dykes of porphyry and trap, than to that of 

 gneiss, mica-slate, and similar crystalline rocks. 



We are, however, informed by Hugi that, in the Alps, 

 granite overlies fossiliferous limestones and slates, equivalent 



* Bulletin dc la Soc. Gcol. du France, tome ii. p. 55. 



