WOLF LAVAS OF MOUNT VESUVIUS. 13 



5. Granites. 



6. Euritic porphyries. 



7. Metalliferous deposits. 



8. Greenstones. 



9. Diluvial deposits. 



10. Eecent deposits. 



The absence of the entire series of sedimentary rocks between the 

 Dyas and the Diluvium leads to the conclusion that during the 

 whole of this long period the region of the Altai" was dry land, and 

 that during the Diluvial period it was covered with water as far as 

 the foot of the mountains. At this time an ocean, extending from 

 the Glacial sea to the Ural, the Altai, and the Caspian and Black 

 Seas, seems to have formed a boundary between Europe and the 

 south and east of Asia. The absence of traces of glaciers, and, in- 

 deed, generally, of any vestiges of a glacial period, such as are so 

 frequently observed in Europe, may be accounted for by the suppo- 

 sition that a current of warm sea-water, passing from the Mediter- 

 ranean to the Glacial sea, took its course along the then existing 

 Altaic coast. The Mammoths, remains of which have been found in 

 some of the caves of the Altai, may have Hved upon large flat islands 

 rising out of the Diluvial sea. This sea having been removed, either 

 by the upheaval of the land or by the draining off of its waters, left 

 behind it numerous lakes, some of which still consist of salt water, 

 and the climate acquired its present continental type. No traces of 

 Tertiary, or Post-tertiary eruptions have been met with. The most 

 recent eruptive rocks are Greenstones, which have broken through 

 all the deposits, up to the metalliferous. Everywhere the old sedi- 

 mentary strata are considerably upheaved and disturbed, but the 

 periods at which these upheavals took place cannot at present be as- 

 certained. 



The metalliferous deposits in the west Altai' are essentially uni- 

 form in type. They consist of sulphate of baryta or quartz, with a 

 great diversity of metallic sulphurets, the products of the decompo- 

 sition of which usually occupy the higher levels. The form of these 

 deposits is very irregular, and they probably owe their origin to the 

 filling up of fissures. They occur especially in the crystalline and 

 sedimentary slates, and also in porphyry, but never in granite or 

 greenstone ; indeed, the last-mentioned rock has broken through a 

 number of them. The metalliferous deposits of the low mountain - 

 chain of Salair, in which granite is almost entirely deficient, form 

 irregular beds in a talcose slate, but are evidently of later date than 

 the rock in which they are imbedded. Sulphate of baryta predo- 

 minates among their constituents. [Count M.] 



On Chelonia from Eibiswald, in Sttria. 

 By Prof. C. Petees. 



[Proc. Imp. Geol. Institute, Vienna, April 6, 1869.] 



Peofessoe Petees compares his new genus Chelych'oj)sis, from Eibis- 



