390 UEAL MOUNTAINS. 



CHAPTER Pursuing our investigations of tlie great features of 

 K.vuiL |.|jg Asiatic continent where it passes into that of Europe, 

 if we proceed from tlie Caucasian isthmus to the noi'th 

 and north-west, we arrive at the territory of the great 

 Soutiieni horizontal and tertiary deposites of Southern Russia and 

 Pofaiii''"^ Poland. These are situated on the western margin of 

 the great Asiatic area of depression. Here we find igne- 

 ous rooks piercing the red sandstone of Jekaterinoslav, 

 together with asphaltum, and springs impregnated with 

 sulphurous gases. 

 Central A. phenomenon so great as that of the central depres- 



depression of gj^j^ ^f ^gia, which resemhles the circular valleys of the 

 moon, could have been produced only b}' such a very 

 powerful cause acting in the interior of the earth, as has 

 been assumed to account for the corresponding features 

 visible on the moon's surface. This cause, while form- 

 ing the crust of the globe by sudden raisings and sink- 

 ings, probably filled with metallic substances the fissures 

 of the Uralian and Altaic chains, injecting into them, 

 from the liquid central regions, these rich veins of ores, 

 and mineral treasures, which now repay the labours of 

 the miner ; while they supply to the philosopher pecu- 

 liar elements by which to classify the various ranges of 

 upheaval, and even to assign a relative chronology to the 

 several mountain chains that range across the continent 

 of Asia, and are continued to the west of Europe. 

 Ural inoun The great chain of the Ural mountains does not pro- 



tain system, pej.jy belong to the mountain systems of Central Asia, 

 being itself the boundary line which separates the con- 

 tinents of Asia and Europe, and having thus an Asiatic 

 and a European slojie, the mineral and geological cha- 

 racteristics of which differ in many important points. 

 This subject has been illustrated at great lengtli, by Sir 

 Roderick Impey Murchison, aided by M. De Verneuil and 

 Count Alexander Von Keyserling, in their valuable work 

 on the geology of Russia in Europe, and the Ural moun- 

 tains. In this work, consideral)le advance is made on 

 the previous observations of Humboldt. The great 



