Structure of the Eastern Alps. 353 



described) it is closed in by the lofty liniestone-ri(!g-e of Blankenstein ; and 

 to the north by a ridge extending from the precipices on the south side of 

 Gosauwang to Gross Rosen-Kogel*. 



In all these mountains the limestone is subordinate to the great secondary 

 system of the Alps, is often highly inclined and contorted^ contains Ammonites 

 and Belemnites, and in other respects exhibits many of its ordinary mineralo- 

 gical characters. 



It would be quite foreign to our object to describe these secondary rocks in 

 detail. We may however remark — that the lofty serrated peaks which shut 

 in the vale to the souths are composed of several varieties of compact, sub- 

 crystalline and scaly limestone, some of which probably pass into dolomites-^- 

 that in the Henner-Kogel there are subordinate beds of brown chert penetrated 

 by white, siliceous veins, and sometimes divided in a septarian form by veins 

 of carbonate of lime — and that in the Moderer-berg the ])revailing rock is a 

 white marble, in one place compact and witii a scaly fracture, in another gra- 

 nular, with cylindrical, crystalline stems probably of organic origin, and with 

 weathered surfaces rarely exposing Terebratulae and other obscure fossils. 



Again, we may remark — that on the north-east side of the valley the ridge 

 of the Rosen-Kogel exhibits a white, crystalline limestone^ and a compact, pink 

 and white-coloured marble, with veins of carbonate of lime and thin, subordi- 

 nate bands of chert — and that rocks of this kind are overlaid by bosses of 

 hippurite-limestone, the largest of which, called tiie Balvenstein, juts out in 

 the dense pine forests on the mountain side north of the village. 



Lastly, we may observe — that the secondary mountains shutting in the valley 

 to the east, are not exclusively composed, like Blossen and the highest ridges 

 of Blankenstein, of Alpine limestone — on the contrary, that the lower ridges 

 of Blankenstein consist of a brown, slaty, calcareous sandstone, and a dull 

 grey, arenaceous limestone, in some parts brecciated, in other jiarts made up 

 of minute fragments or concretions, giving the rock an appearance of oolitic 

 structure — that in these beds are some Belemnites, and many small Gryphites 

 (identified with the Gryphaa glohosa of the chalk or chalk marl) — that in 

 their range westward they graduate into earthy, impure, arenaceous lime- 

 stone, of grey, green, and pinkish colours — and that the whole system, at the 

 Brill Graben, abuts against, or is carried under, the marls and slaty sandstones 

 of a still newer series composing the Ressenberg ridge f. 



Such are the secondary rocks surrounding the valley of Gosau. The hip- 

 purite-rock on the south side of the Rosen-Kogel, and the green-sand series 



* Plate XL. t Plate XXXVI. fig. 10. 



VOL. III. SECOND SERIES. 2 Z 



