PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



1829. No. 13. 



_ Nov. 6th, 1829. — The Society assembled this evening For the Ses- 

 sion. 



George Biddell Airy, Esq. M.A. Fellow of Trinity College, Cam- 

 bridge, and Professor of Astronomy in that University ; John Mac*, 

 pherson Grant, Esq. of Ballindalloch, N. B. and attached to His Ma- 

 jesty's Legation at Turin ; John Heywood Hawkins, Esq. of Bignor 

 Park, Sussex ; Philip Duncan, Esq., Fellow of New College, Ox- 

 ford ; and William Cavendish, Esq., M.P. M.A. of Trinity College, 

 Cambridge, and Belgrave-square London, were elected Fellows of 

 this Society. 



A Paper was read, " On the Tertiary Deposits of the Vale of Go- 

 sau in the Salzburg Alps ; by the Rev. Adam Sedgwick, Pres. G.S. 

 F.R.S. &c, and Roderick Impey Murchison, Esq. Sec. G.S. F.R.S. 

 &c." 



The authors present this as the first of a series of memoirs in which 

 they hope to throw some light on the structure of the tertiary forma- 

 tions in Salzburg and Bavaria, and their varied relations to the 

 secondary rocks of the Austrian Alps. 



These deposits, the highest members of which descend into the 

 fiat regions near the banks of the Danube, become, in their lower 

 groups, more elevated and more highly inclined ; and, as they ap- 

 proach their southern or Alpine barrier, are sometimes vertical : 

 whilst in the valley of Gosau and far within that barrier, formations 

 with the same organic remains are found at much higher elevations, 

 inclosed in Alpine limestone, on which they rest unconformably, and 

 in a nearly horizontal position. This deposit of Gosau the authors 

 conceive to have been formed in one of the arms of an ancient sea 

 which, like the present salt-water lochs of Scotland, must have pe- 

 netrated deeply into the then existing valleys of the Alps ; whilst its 

 actual position incontestably proves that it must have been prodi- 

 giously upheaved at some time posterior to the epoclrof its formation. 



In ascending the drainage of the Traun to the district under 

 review, patches of these tertiary formations are described as occurring 

 in various small transverse valleys between Gmunden and Ischel j 

 but these are comparatively at low elevations, and all traces of them 

 are lost in the higher regions between Ischel and the Lake of Hall- 

 stadt, which is about 1 700 feet above the level of the sea. The 

 valley of Gosau is described as situated more than five miles to the 

 west of that lake and about 900 feet above its level. The formations 

 which the authors consider Tertiary, occupy the flanks of this valley, 

 and are chiefly exhibited in two hilly ranges, the Horn on the west, 



