THE URAL MOUNTAINS. 391 



meridional chain of the Ural mountains extends over chapter 

 18' of latitude, from the Arctic Ocean on the north, ac- ^^^"- 

 cording to Humboldt, to the higher grounds between 

 the Aral and the Caspian Sea. The Ural mountains Minerals anJ 

 are composed of crystalline and slaty rocks, abounding °^'^ 

 in minerals and metallic ores. Numerous outbursts of 

 eruptive rocks have broken up, and overflowed the ear- 

 lier strata, rendering their exact separation and orderly 

 classification extremely difficult. In the remarkable 

 series of geological changes which have produced these 

 results, all the richest metalliferous ores have been pro- 

 duced on the Asiatic flank, where they are found in 

 veins, masses, or irregular deposits. This region accord- 

 ingly supplied, for a considerable period, one of the 

 chief sources of economic mineral wealth, and is still 

 wrought for this purpose with considerable success. 



In accounting for some of the remarkable geological Geoloricai 

 phenomena discoverable in the Ural mountains, the ^ enumena. 

 authors of the Geology of Russia and the Ural Moun- 

 tains remark : — " The low region of Siberia, into which 

 these folds or corrugations pass, is to a great extent 

 occupied by granitic rocks. With very limited excep- 

 tions, true gi-anites seem never to enter into the higher 

 portions of the Ural, the culminating points of which Character- 

 generally consist of altered palseozoic strata, usually in 

 the state of quartzose and chioritic rocks, sometimes as 

 mica schists, with saccharoid marble, whilst promonto- 

 ries of greenstone, porphyry, and syenite, indenting and 

 breaking in, as it were, upon the central and sub-crystal- 

 line ridge, often constitute the highest peaks. 



" Notwithstanding, however, the striking contrast which Successive 

 is presented by the opposite sides of the Ural chain, we 

 convinced ourselves that, in the early periods, there had 

 taken place, all over this region, and probably extending 

 far into Siberia, a deposition of Silurian, Devonian, and 

 Carboniferous strata, which, by the linear outbursts of 

 granitic rocks on some lines, and of porphyries and green- 

 stones on others, in lines from N. to E., was thrown up 



