334 Professor Sedgwick and Mr. Murchison on the 



are bent into irregular, flattened domes arching over the dykes, and probably 

 over a still larger, concealed mass of trap below. 



On the opposite side of the gorge there are other phenomena, placing 

 perhaps in a still more striking point of view, the nature of the elevatory forces, 

 which have acted on the neighbouring strata. From the north side of the 

 Schinberger-Ach rises a mountain called the Bolghen, the base of which is 

 presumed to be of primary rock, because large, angular masses of granitoid 

 gneiss and mica schist, are there seen to rise through the thick, grassy covering. 

 On ascending the mountain side, we again found gneiss protruding above the 

 surface for 300 or 400 feet ; and from these facts we concluded that all the 

 masses of primary rock were in situ. 



Upon a close examination, the granitoid rocks are found to be brought into 

 contact with various members of the green-sand series, which are thereby so 

 singularly displaced as to render it almost certain, that the crystalline masses 

 have been upheaved at a period posterior to the deposition of the overlying 

 beds. For, within the distance of less than a mile, the crystalline rocks are in 

 one place brought in contact with a coarse millstone grit; in another, with slaty, 

 ereen, micaceous sandstone: and in a third, with calcareous, fucoid shales; 

 all of which beds are tilted off in every possible direction, and at high angles 

 of inclination, from the various, salient points of the primary masses. As the 

 basaltic dykes appear only at a short distance on the opposite side of the gorge, 

 and penetrate the same series of sandstones and shales, it seems probable that 

 the volcanic matter, which was driven up among the strata of green-sand, did 

 not make its way through the gneiss ; but acting on it in mass, raised it up, 

 as a great lever, among the overlying deposits, dislocating them, and breaking 

 them in the manner above described*. In this locality we seem, therefore, 

 to have a key to the explanation of the real nature of some of the great, ele- 

 vatory movements of the Alpine chain f. 



Before we quit this subject, we may remark, that the last, great movements 

 of elevation, must have taken place after the deposition of the sandstones and 

 conglomerates of the outer ridge of the Rethenberg, as must be evident by 



* We did not examine the eastern side of tlie valley opposite Ober Mieselstein : we must tlieie- 

 forc refer to the published memoirs of Dr. Boue for an account of the minerals and trap rocks 

 which occur in that locality. We are at a loss to comprehend how he can include the primary 

 masses we have been describing in a conglomerate of the green. sand ; and we are still more sur- 

 prised that he should attempt to assimilate this supposed conglomerate to the system of the 

 Rethenberg, which is exterior to all the secondary portions of the chain. 



\ A similar instance of the upheaving of primary rocks in a solid state, and a consequent de- 

 rangement of the overlying shelly strata, was described, by one of the authors, in a memoir on the 



