vii HASISADRA'S ADVENTURE 275 



southern division, they become extremely saline 

 in consequence of the intense evaporation. The 

 Aral Sea, though supplied by the Jaxartes and 

 the Oxus, has brackish water. There is evidence 

 that, in the pliocene and pleistocene periods, to go 

 no farther back, the strait of the Dardanelles did 

 not exist, and that the vast area, from the valley 

 of the Danube to that of the Jaxartes, was 

 covered by brackish or, in some parts, fresh water 

 to a height of at least 200 feet above the level 

 of the Mediterranean. At the present time, the 

 water-parting which separates the northern part 

 of the basin of the Caspian from the vast plains 

 traversed by the Tobol and the Obi, in their 

 course to the Arctic Ocean, appears to be less than 

 200 feet above the latter. It would seem, there- 

 fore, to be very probable that, under the climatal 

 conditions of part of the pleistocene period, the 

 valley of the Obi played the same part in relation 

 to the Ponto-Aralian sea, as that of the Kishon 

 may have done to the great mere of the Jordan 

 valley ; and that the outflow formed the channel 

 by which the well-known Arctic elements of the 

 fauna of the Caspian entered it. For the fossil 

 remains imbedded in the strata continuously 

 deposited in the Aralo-Caspian area, since the 

 latter end of the miocene epoch, show no sign 

 that, from that time onward, it has ever been 

 covered by sea water. Therefore, the supposition 

 of a free inflow of the Arctic Ocean, which at one 



