Geology ofiha Austrian Alps. 15 



not exist, yet that there reigns a great similarity between the 

 succession of the southern and northern alpine deposites. It 

 has been long known, that, in Carinthia, especially near to 

 Bleiberg, true transition rocks, even with their characteristic 

 fossil shells, make their appearance. Our authors have add- 

 ed new and interesting details to those already known, in re- 

 gard to this isolated occurrence among the Alps, and excite 

 the wish that these ancient rocks may be farther traced, with 

 the view of ascertaining whether or not they do not actually 

 extend under the secondary rocks, in the direction of Idria. 

 Now, as these rocks are entirely unknown along the whole of 

 the northern alpine chain, from the Mediterranean Sea to the 

 Carpathians, and as they do not occur in the Italian Alps, it 

 would have been better to have presented this fact as an isolated 

 accident^ rather than endeavour to join these rocks with other cal- 

 careous and arenaceous rocks, without, or nearly without, organic 

 remains, which some may be disposed to call transition, while 

 others will refer them to the secondary class. Besides, if these 

 crystalline masses, containing encrinal beds, described as occur- 

 ring on the northern side, are truly transition, certainly their 

 characters differ from those of the rocks of Carinthia, containing 

 shells. On the other hand, we see the term greywacTce applied 

 to rocks on the northern side of the Alps, which make a transi- 

 tion from the micaceous or chloritose quartzose rocks, to others 

 with a still more arenaceous character. We confess that these 

 last mentioned conglomerated masses cannot be compared with, 

 or referred to, the grey wacke of the Hartz or the south of Scot- 

 land, but to us appear mere varieties of quartzose talcose rocks, 

 deposites also well known in Scotland, which are, in our opi- 

 nion, less affected and altered by igneous agents than the other 

 primary, but formerly arenaceous rocks. 



After these general observations on our authors' mode of 

 treating the subject, we shall now take the liberty of examining 

 the divisions which they propose. They distinguish, in the 

 Alps, 1. With all geologists y a central primary aans. 2. Crys- 

 talline rocks, with limestone beds, containing Jexo organic re- 

 mains^ the system graduating into rocks agreeing with the or- 

 dinary transition type. 3. Red marl, sandstone, gypsum, <J»c. 

 containing, in parts of their range, large subordinate masses of 



