Structure of the Austrian yllps,<$-c. 83 



plains of Bavaria. To these may be added, a complete tra- 

 verse, made by one of the authors of this paper in the 

 summer of 1828, from the subalpine plains of Italy, over the 

 Brenner and Seefeld pass, to the plains of the Danube. 



In all these regions the structure of the Alps, when consi- 

 dered only in a general point of view, is of great simplicity; 

 the chain being composed of an axis of primary and transition 

 rocks, chiefly of a slaty texture, flanked and surmounted by 

 the two great secondary calcareous zones; which are in their 

 turn surmounted by the tertiary sandstones and conglome- 

 rates, descending on one side into the plains of Italy, and on 

 the other into the elevated plains of the Upper Danube. We 

 have endeavoured to show, in papers read at former meetings 

 of this Society, that the chain of the eastern Alps has been 

 elevated at successive epochs ; and (agreeably to the views first 

 published by Dr. Boue) that it has undergone a great move- 

 ment since the tertiary period. By these successive elevations 

 the relative position^ of its subordinate parts has been greatly 

 deranged ; the northern and southern calcareous zones being 

 in many places completely rent asunder, and having their 

 component strata thrown into the most violent contortions. 



To the east of that part of the valley of the Inn which in- 

 tersects the Alpine limestone, the derangements of the chain 

 are, we believe, in no instance so great as to produce an en- 

 tire inversion in the order of the calcareous formations ; and 

 the transition rocks and red sandstone series on the flanks of 

 the central axis are uniformly surmounted by the lower part of 

 the system of Alpine limestone. But on the west side of the 

 great chasm through which the Inn escapes into the plains at 

 the northern foot of the Alps, the dislocations are more com- 

 plex; as there appear to be two distinct axes of elevation 

 ranging nearly parallel to each other; one along the true 

 geological central line of the Alps; the other through the 

 centre of the northern calcareous zone. The effect produced 

 by the second axis is such, that some of the higher mem- 

 bers of this zone are carried, with an inverted dip, directly 

 against the central chain, and appear to pass under it. This 

 singular derangement of the strata passes through the dolo- 

 mitic peaks of the Rhetian Alps at Mittenwald ; but how far 

 it ranges towards the west, we had no means of ascertaining : 

 we have been informed, however, that similar derangements 

 may be traced into the heart of Switzerland. 



Having thus noticed the general position of the great mi- 

 neral masses of the eastern Alps, it may be expedient briefly 

 to explain the transverse section which forms, the chief basis 

 of our observations, and to which nearly all the subdivisions 



M 2 of 



