4 GEOLOGICAL MEMOIRS. 



ganese-graphite, quartz, chalcedony, several ores of manganese, the 

 variety of arsenical pyrites known under the name of "Loellingite," 

 and grey sulpho-antimoniate of copper. 



In M. Miinichdorfer's opinion, the ferriferous deposits of Hiitten- 

 berg are of contemporaneous origin with the associated crystalline 

 limestone, and have not resulted from injections or sublimations. 



M. Lipoid, who surveyed this district in the summer of 1854, 

 remarks that it is a mistake to suppose that all the deposits of iron- 

 ore occurring on the southern slope of the Carinthian Central Alps 

 belong to one and the same formation or ferriferous zone. Geological 

 investigations have shown the necessity of a separation between the 

 western deposits (Kremsgraben near Gmiind and Turrach) from the 

 eastern ones (Hiittenberg, Walch, &c.). MM. Stur and Peters have 

 proved that the western group belongs to the lowest portion of the 

 Carboniferous formation ; while the eastern group is always enclosed 

 in crystalline slates, such as mica-schist, gneiss, &c. Moreover, the 

 former is due essentially to pyrites and hydroxides of iron, and their 

 decomposition ; while the latter has for its constituent mineral the 

 carbonate of iron, partly reduced to the state of brown hydroxide. 



The geodes (Kernerze), described by M. Miinichdorfer, are of 

 great service in the illustration of the origin of the ferruginous 

 deposits and of the changes they have undergone. MM. von Haidinger 

 and A. von Morlot have proved that the carbonate of iron is pro- 

 duced by a catagenic (reductive) process going on at great depths ; 

 in opposition to the anagenic (oxidating) origin of the hydroxide of 

 the same metal, caused by the influence of air and water^ where they 

 have access to the ferriferous deposit. Observation on a larger scale 

 has confirmed this explanation ; the carbonate of iron occupying the 

 deeper parts of the ore-mountain of Hiittenberg, which are inac- 

 cessible to air and water ; while the hydroxide is found nearer to the 

 surface. The presence of red oxide of iron at the highest level may 

 depend upon particular circumstances, deserving further investigation; 



[Count M.] 



Mineral Vein near Guadalajara in Spain. By A. Breithaupt. 



[Leonhard u. Bronn's N. Jahrb. f. Min. u. s. w. 1855, p. 705 ; and Hartmann's 

 Berg- u. Hiitten-mann. Zeitung, 1854, 2, p. 9.] 



The formation of the main lode in the mining district of Hiendelaen- 

 zina near Guadalajara, in Spain, agrees very much in its characters 

 with that in the Neue Hoffnung Gottes mine at Braunsdorf near Frei- 

 berg. Quartz is the oldest member, and partially massive. With 

 the silver minerals, — sulphuret of silver and antimony (schilfglaserz, 

 freieslebenite), crystallized, and even in compact masses, red silver 

 (rothgiiltigerz, pyrargyrite), compact and crystalHzed, and miargy- 

 rite, as yet found only in a compact form, — occur bournonite and 

 galena. In the shallow levels, which especially carry galena, car- 

 bonate of lead and sulphate of lead also occur. [T. R. J.] 



