and TTritings of Baron Leopold x>on Bitch. 223 



non-quartziferous. The phenomena of which we have spol^en 

 as occurring in the Alps, served therefore as the type of simi- 

 lar features over the whole surface of the earth, and the same 

 conclusions were applicable to both. As all mountain-chains 

 must have been formed by elevation, the conclusion was easily 

 drawn, that the black porphyry had everywhere caused this 

 elevation ; likewise, that it is every where newer than the red, 

 and that the masses of dolomite so frequent at the edges of the 

 older rocks were produced by it in the manner already de- 

 scribed. Von Buch applied these views to two of our more 

 important ranges of mountains, the Hartz and Thilnnger 

 JFald, with the view of shewing that the same phenomena are 

 just as distinct there, though on a much smaller scale, as in 

 the Alps, and that it is only necessary to regard them under 

 a point of view which, though differing much from previously 

 entertained opinions on the subject, is not the less perfectly 

 well founded in the nature of things. 



The importance of these views, and the influence which 

 they exercised on so many subjects which have since become 

 the unalienable property of the science of geology, render it 

 necessary to subject them to a strict and calm examination. 

 It appears at first sight but little probable that the numerous 

 alterations which have taken place in relative positions as to 

 level, and in consequence of the breaking up of the surface of 

 the earth, should have been the work of one and the same 

 erupted volcanic formation ; for, in all epochs of the forma- 

 tion of the crust of the earth, volcanic rocks have made their 

 appearance at the surface, often of greater extent and in 

 larger quantity than the masses of black porphjTy, and we can- 

 not assume that one alone of them all should have been able 

 to effect such striking changes. This is particularly worthy 

 of attention, and was left out of consideration in applying the 

 discoveries made in the Alps. It is also necessary to deter- 

 mine, at what relative period of time the changes happened 

 which were effected by the black porphyi'y. When the first 

 accounts were published of the dolomite and melaphyre, data 

 of a more minute kind were awanting as to the strata which 

 had been more especially subjected to these operations. 

 Geologists were then inclined to regard the limestones, which 



