90 Prof. Sedgwick and Mr. Murchison on the 



We did not examine in detail any of the great deposits of 

 sparry iron ore which characterize the eastern Alps. Although 

 not, perhaps, on the same exact parallel, they chiefly occur 

 under the system of secondary, red, gypseous marl and sand- 

 stone, along with a fine grit or grauwacke which is more or 

 less calcareous. According to information which we owe to 

 His Imperial Highness the Archduke John, who from personal 

 examination is most intimately acquainted with the mineral 

 structure of every part of the eastern Alps, the following 

 are among the most important localities where the ore has 

 been extracted for use: — Freisnitz near the Somring; Ricke- 

 nau ; Neuberg ; Veitsch ; Niedereibl ; Goldrath near Marian- 

 zell ; Eisenerz; Radmar; Admont; Lietzen near Aussee; 

 and Winterwald south of Werfen *. To the south of the 

 iron ore runs a low chain of limestone more or less argilla- 

 ceous, which between Neuberg and Admont is said also to 

 contain several small veins of iron spar. In two localities, 

 one near Aussee, and the other at Imlau Graben near Mari- 

 anzell, the ore is said to overlie red gypseous marls. From 

 all these facts we conclude, that the greatest part of these re- 

 markable deposits are close to the confines of the lowest se- 

 condary group of the Alps, and perhaps in some instances 

 enter partially into its composition f. 



It would be incompatible with our present object to enter 

 into any longer details respecting the structure of the great 

 series of rocks above described : but it may be asked how we 

 prove them to be of the transition class, since the organic 

 remains imbedded in them exhibit no specific characters. 

 Considering the crystalline structure of some of the secondary 

 formations of the western Alps, it would be difficult to meet 

 this objection, had we not found an answer to it in the facts 

 exhibited by our transverse section on the south side of the 

 central axis. 



On the right bank of the Drave below Paternion the forma- 

 tions of crystalline slate are surmounted by grauwacke, shale, 

 and red sandstone, forming the base of the Carinthian lead hills. 

 These formations are not so well exposed, but the order ap- 

 pears to be precisely the same, as on the north side of the 

 axis. A great fault ranges up the valley of Bleiberg, between 



* To the same Illustrious Personage we are indebted for many other de- 

 tails connected with the immediate objects of this paper. The section PI. II. 

 fig. 4, which we owe to Professor Rippl, shows that the geological rela- 

 tions of the great deposits of sparry iron ore near Eisenerz are similar to 

 those above described. 



f This conclusion is, we believe, in accordance with the opinion of 

 Dr. Boue. 



the 



