20 GEOLOGICAL MEMOIKS. 



C. Lime-felspars. 



7. Andesiwe Seeies. Lime 6 to 10 per cent. 



Compact. Andesine, in part ; Saccharite, Glocker ; Oligoclase, 



in part ; Labradorite, in part. 

 Glassy. Andesine, Ahicli ; Manilite, Thomson. 



8. Labkadoe Seeies. Lime 10 to 13 per cent. 



Compact. Labradorite, Wei^ner; Sanssurite, in part; Anor- 



thite of Corsica. 

 Glassy. Glassy Labradorite, Mornite (?). 



9. Bytownite Seeies. Lime 13 to 17 per cent. 

 Compact. Bytownite, Thomson. 



10. Anoethite Geoup. Lime 17 to 20 per cent. 



Drusy. Anorthite, G. Rose ; Cbristianite, Monticelli. 

 Compact. Ancrthite in Eucrite; in "Protobastitfels," Streng.\ 

 Glassy. Anorthite in Lava ; Thjorsaurite, Genth. 



D. Baeyta-eelspae. 

 Hyalophane, Sartoriiis v. Waltershausen. 



E. BoEOJiT-EELSPAK. 



Danburite, Sheparcl. [J. M. & H. M. J.] 



On the Teachttic Eoematiojsts of Schemnitz. 

 By Baron Awdeiabt. 



[Proceed. Imp. Geol. lustit. Vienna, July 18, 1865.] 



These metalliferous rocks, the site of the most ancient and extended 

 mining operations in Hungary, consist of greenstone-trachytes, 

 which are rendered conspicuous by their lengthened ridges, which 

 also separate them from the genuine trachytes, whose tops generally 

 assume a pointed shape. Between both runs a zone of greenstone- 

 tuffs, in the form of a low ridge with soft outlines, locally encroach- 

 ing into both the greenstone and the genuine trachytes, and ex- 

 hibiting petrographical transitions into both. They are best charac- 

 terized by their easy decomposition into gravel, and are (at least 

 most probably) connected with breccias, conglomerates, shales, and 

 sandstones, including vegetable remains and patches of fossil fuel. 

 These breccias contain fragments of greenstone and of genuine 

 trachytes in the neighbourhood of those rocks and M^here they are 

 contiguous to them. They may be supposed to be contemporaneous 

 with the extensive tuflfaceous deposits leaning on the masses of 

 genuine trachyte, and to have undergone considerable depression, 

 subsequent to certain extensive volcanic and plutonic eruptions, 

 which are j)roved to have occurred by the existence of the basaltic 

 cone of Mount Calvary, close to Schemnitz, and of eight distinct 

 veins of Rhyolite. The basaltic veins of Giesshiibel run through 

 genuine trachyte, and contain conspicuous fragments of this rock. 

 Lower Triassic deposits have been stated to occur beneath the 

 metalliferous greenstones worked at and around Schemnitz. 



[Count M.] 



IV 



4 44 2 



t 



