238 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 13, 



not entirely wanting, are, at all events, feebly exhibited in Northern 

 Europe. But passing from the survey of these valuable exceptional 

 cases, which have been left for our instruction, I will now point out a 

 few examples illustrative of the manner in which several consecutive 

 Alpine formations have been first convoluted, then often inverted, and 

 finally snapped asunder by enormous faults. To treat such a subject 

 in the manner it deserves would require much more detailed knowledge 

 than I possess, and the present notice must, therefore, only be viewed 

 as affording data to assist in explaining the origin and progress of 

 such great mutations. 



Let the geological features of any one region of the Alps be ap- 

 pealed to, and it will be seen, that whatever be the major axis of the 

 crystalline mass* in its centre, such also is the prevailing direction 

 of all the sedimentary deposits which lie on either side. Thus in 

 the Eastern Alps, we see two principal ellipsoidal ranges of granite, 

 the one extending from the Iffiger Spitze above Meran to the envi- 

 rons of Brunneckenf, the other of nearly equal extent in the high 

 region near the sources of the Mur, and extending along the left 

 bank of that river to form the nucleus of the Noritian x\lps. These 

 ellipses, trending from "W.S.W. to E.N.E., mark distinctly the 

 major axis of the Eastern Alps ; whilst to the south of Vienna the 

 prolongation of this axis is indicated in the nucleus of the Leitha 

 Gebirge|;. Now this direction from W.S.W. to E.N.E. is likewise 

 that which has been impressed on all the sedimentary masses of 

 these Eastern Alps, of transition, secondary or tertiary age, whether 

 they be successively examined northwards to the valley of the Da- 

 nube or southwards to the plains of Venice. Minor parallel ellip- 

 soids of crystalline rock, indeed, appear in the Venetian Alps both at 

 Recoaro and its neighbourhood and in the Cima d'Asti, which, 

 whether they be mica schists or granitic rocks, ha^ve the same rela- 

 tions to the enveloping younger sedimentary deposits. Such also are 

 the major axes of the great masses of crystalline rocks which occupy 

 the central tracts of the Tyrol, the chief part of the Alps of Lom- 

 bardy, and the nuclei of the Swiss Alps, and such also is the domi- 

 nant strike of all the associated sedimentary deposits in these regions. 



To the west of the longitude of Berne the chain assumes more 

 of the north and south direction, and there again the sedimentary 

 rocks, to a great degree metamorphosed, run parallel to the axes of the 

 rude ellipses of Mont Cervin and Mont Blanc and their prolonga- 

 tions. And here it is to be remarked, that as we follow the chain 

 from N.E. to S.W. we pass from the clearest types of the sedimentary 

 rocks, and at length in the Savoy Alps are immersed in the highly 

 altered mountains of secondary limestone before described. I am 

 unable to define the manner in which the chief axes of these moun- 



* The word * crystalline mass ' is meant to include granite, gneiss, mica schist, 

 marble, &c., and in short all rocks, whether formed by eruption or by raetamor- 

 phism of pre-existing deposits, which are now in a crystalKne condition. 



t M. von Buch specially called my attention to this ellipsoid of granite, around 

 which all the rocks are powerfully metamorphosed (see ante, p. 167). 



J Trans. Geol. Soc. vol. iii. p. 303 ; and Map, pi. 35. 



