352 Professor Sedgwick a7id Mr. Murchison on the 



description, as we have examined it in all its bearings, and have procured from 

 it a better series of fossils than from any other corresponding^ locality. 



1. Overh/ing Deposits of the Vallei/ of Gosau*. 



Before we visited the Alps, these deposits had been described by MM, 

 Keferstein and De Lill. The former author had been led, partly by an erro- 

 neous identification of several of the Gosau shells with certain secondary 

 fossils, and partly by some deceptive appearances in the dip of the strata, to 

 consider the whole of them as inferior or subordinate to the adjoining- sali- 

 ferous limestone. Our friend M. de Lill too clearly perceived the overlying- 

 position of one portion of the strata, and was too well acquainted with the 

 structure and fossils of all the neighbouring formations, to commit the error 

 of M. Keferstein : he therefore regarded the insulated deposits of Gosau as a 

 system of newer secondary beds, resting unconformably on the saliferous lime- 

 stone. We, however, think that he placed them lower in the series than they 

 ought to be, and that he also in some measure misinterpreted the evidence 

 of the fossils f. Before we proceed to describe the accompanying sections, it 

 may be expedient briefly to notice the position of Gosau Thai, and the struc- 

 ture of the surrounding mountains. 



In ascending the valley of the Traun from Traun-See to the Lake of Hall- 

 stadt, we pass a magnificent succession of phenomena, and almost at every 

 step see proofs of the vast dislocations of the chain. 



An Alpine gorge, called Gosauwang, commencing on the west side of the 

 Lake of Hallstadt, and running several miles nearly due west, ascends rapidly, 

 through an elevation of more than 800 feet, to the valley of Gosau. Every 

 part of this gorge is narrow ; and in many places it presents on both sides a 

 succession of mural escarpments, between which there is no vestige of any 

 deposits extraneous to the secondary limestone : and it might be described 

 as a great cleft in the older calcareous chain, which had allowed an escape to 

 the waters of the upland valley. 



It forms no partof our object to describe the picturesque features of the beau- 

 tiful valley of Gosau; but we may observe, that it is shut in towards the south 

 by a gorgeous, serrated barrier of Alpine limestone, the highest pinnacles of 

 which (in the Dachstein) reach the elevation of more than 10,000 feet above 

 the level of the sea ; whilst to the east (with the exception of the gorge above 



* See Plate XXXVI. fig. 10. 1 1. & Plate XL. 



t As far as regards the age of the overlying deposits of Gosau, M. de Lill's opinions seem to 

 have been nearly adopted by Dr. Boue, none of whose memoirs on this subject had, we believe, 

 appeared when the abstract of our paper was published by the Geological Society. 



