46 NATURE HISTORY OF 



from the great central chains of Asia, converting them, 

 during the melting of the snows, for a considerable 

 period, to the breadth of marine straits, and carrying 

 away hills, banks, and forests, in their course ; and con- 

 stantly shift the soil in such a manner, that speaking 

 of a more elevated basin, Cochrane remarks : " It 

 is but twenty years since the present centre of the 

 river Selinga was the centre of the city Selenginsk." 

 The Obi, Jenissei, and Lena, all overflow to a vast 

 extent, as was already remarked by Abulghazi ; and 

 no doubt, the deposits of so many streams contribute 

 largely to the extension of the shores in the Arctic 

 Circle ; but the increase thus obtained, cannot be of 

 sufficient extent to account for the rapid progress of 

 the land, even where the depth is inconsiderable, and 

 little current exists. It militates against the conclu- 

 sions of the most scientific travellers who have visited 

 the localities ; among whom Strahlenberg, Pallas, and 

 Humboldt, stand conspicuous : and is an opinion, more- 

 over, that every new research tends to strengthen, and 

 one in unison with the belief of all the barbarous tribes 

 that wander over those inhospitable regions. 



