THE HUMAN SPECIES. 51 



north, to Lake Aksakal, or ultimately reach the Tobol 

 or the Ichim, and terminate in the Polar Sea. 



Such are the abstracts of statements, and the in- 

 ferences, which establish the existence of an Asiatic 

 Mediterranean, or rather a lagoon sea, in the earlier 

 period of man's presence on the earth ; for, until ages 

 after, though in a gradual progress of evanescence, 

 desiccation was not effected till the bed and mouth of 

 the Obi were elevated, when the mass of waters in the 

 lagoons, no longer fed by external supplies, and being 

 of themselves insufficient to maintain the equilibrium 

 against percolation, and the power of solar heat upon 

 sand and hard clay, absorbed such an amount of mois- 

 ture, that the level of the dry plains is now far below 

 the surface of the ocean. But, so long as there was a 

 sea, Northern Europe was insulated, inaccessible to 

 migration, excepting on the winter's ice, and in the 

 skin or birchen kayaks of polar nations. Geographi- 

 cally, our best course is now to continue the description 

 of the progressive rising of the Arctic soil in Europe, 

 and to return by the Mediterranean to Western Asia, 

 because the chief phenomena affecting changes on the 

 earth's surface are again common to both quarters of 

 the world ; in the north, referring mainly to the same 

 effects as already noticed in Asia, but with more unde- 

 niable proof; and, in the south-east of the Mediter- 

 ranean, marked by volcanic perturbations, passing 

 from time to time through Western Asia to Africa, and 

 sometimes extending convulsively to Western Europe 

 and even to the Azores. 



