354 Professor Sedgwick and Mr. Murchison on th,e 



on the west flank of the Blankenstein ridge, escaped our observation during our 

 first visit to this valley : and their discovery was not without importance, as 

 they olTer us a new proof of the enormous derangements of the chain, and 

 give us new terms of comparison between these overlying deposits and others 

 of the same age, on the outskirts of the Alps, described in the former chapter*. 



The waters which descend from the glaciers of the Dachstein are first re- 

 ceived in a basin of Alpine limestone, where they form a lake, called Hinter 

 Gosau See, 1300 feet above the level of the valley : thence they rapidly descend 

 through a narrow gorge into a larger lake, called the Vorder Gosau See. From 

 this basin they emerge into the fiat and cultivated meadows of Gosau Thai ; 

 out of which, after meandering southwards for several miles, they suddenly 

 deflect to the east, and rush down the gorge of Gosauwang into the Lake of 

 Hallstadt. 



On the west side the valley is shut in by a remarkable ridge, the highest 

 part of which, cafled the Horn, is, according to our computation, more than 

 2000 feet above the level of the village, and therefore about 5000 feet above the 

 level of the sea. This ridge abuts against the great, serrated barrier before 

 mentioned, then ranges nearly due north, and in that direction terminates 

 against the Kalenberg : it also forms the parting of the waters, which on the 

 west side descend to Abtenau, and after traversing a gorge of Alpine limestone 

 flow into the Salzaf. 



In mineralogical character the beds of this ridge diff"er entirely from those 

 of the surrounding calcareous mountains. They are much less inclined, are 

 not contorted, and are composed of variously coloured sandstones, marls, and 

 shales ; some of which contain innumerable organic remains in a state of 

 perfect preservation. 



In following these beds towards their north-western limit near Pass Geschitt, 

 we did not find them in (heir line of prolongation plunging under the older 

 calcareous chain of Rosen-Kogel : on the contrary, some of the inferior beds 

 gradually acc^uired a considerable inclination, and were found to rest upon a 

 highly-inclined conglomerate. This conglomerate, here and there presenting 

 appearances of alternating with some of the marl and shale beds, rises to a 

 great elevation on the side of the neighbouring chain, passing above the 

 forests to the base of the highest precipices of limestone. From thence it 

 descends, and continuing throughout in a position perfectly unconformable to 

 the older rocks, passes under the whole system of the Horn, reappearing at its 

 base in the valley of Russbach ; where it separates the secondary red sand- 



* Siqrra, p. 346, &c. f Plate XXXVI. fig. U. 



o 



