TCHIHATCHEFF ON THE ALTAI DISTRICT. 551 



rocks, are also in fact enormous sedimentary deposits more or less 

 metamorphosed. It appears to be the case that one of the prevail- 

 ing features in the general contour of the Altai consists not only 

 in a terrace-like arrangement of the great masses which compose 

 it, but also in a certain rounded or swelling outline of these ter- 

 races, suggesting the agency of plutonic forces beneath the surface, 

 sufficient to produce these undulations of the sedimentary crust 

 and the frequent metamorphism, but often without leaving any 

 marks of violent disturbance or disruption, and without the presence 

 of igneous rocks at the surface to account for the alterations that 

 have taken place. 



The more ancient rocks of the Altai present, in some places, the 

 apparent anomaly of perfectly horizontal stratification, immediately 

 adjacent to indications of disturbance more or less violent, and 

 one result of this, especially in the eastern part of the district, is 

 recognised in the absence of bold and picturesque outlines, and the 

 prevalence of those smooth rounded contours and straight lines 

 wh^ch fatigue the eye of the traveller, and which may be compared 

 with the appearance of the well-known Sierra Nevada of Spain, 

 probably produced by the same geological structure, and exhibiting 

 the same character along a line upwards of 120 miles in length, 

 presenting a strikingly dreary and monotonous appearance. The 

 districts of this kind in the Altai consist, as in Spain, of a long 

 ridge with a flattened summit composed of horizontal beds not ac- 

 companied by any rocks of decidedly plutonic origin, but composed 

 of mica schist and clay slate passing into chloritic schist, all pro- 

 bably of the older pakeozoic period. 



The structure of the Altai district, as indicated by the direction 

 of the mountain chains, is fully confirmed by geological investi- 

 gations concerning the strike of the different beds ; those in the 

 western district running N. W. by S. E., and those in the east at 

 right angles to this direction. Where these two lines of elevation 

 cross one another we may remark on the one side that kind of inter- 

 lacing and entanglement by which the system of the Saiansk is 

 almost everywhere confounded with that of the Altai, properly so 

 called, and on the other side the considerably greater altitude of 

 the mountains of the eastern compared with those of the western 

 district. The highest point of the Altai range is precisely in the 

 intersection of these two axes of elevation, and the lake of Teletzk 

 in the immediate vicinity of the intersection is also due in all pro- 

 bability to the same geological causation. The eastern Altai is, 

 hoAvever, remarkable for the number of lakes of great depth which 

 abound in it, while, with the exception of the celebrated Lake of 

 Kolyvan, the western district contains few worthy of note until we 

 reach in its western extremity those singular salt lakes which be- 

 long to a different group of geological phenomena. The date of 

 the elevation of the western Altai seems, from some appearances, 

 to have been contemporaneous with that of the Ural.* 



* With reference to this subject the author in the resume quoted, offers some 



