278 HASISADRA'S ADVENTURE vn 



the deepest of which, in the province of Seistan, 

 probably descends to the level of the Indian 

 Ocean. These depressions are occupied by salt 

 marshes and deserts, in which the waters of the 

 streams which flow down the sides of the basin 

 are now dissipated by evaporation. I am ac- 

 quainted with no evidence that the present 

 Iranian basin was ever occupied by the sea ; but 

 the accumulations of gravel over a great extent 

 of its surface indicate long-continued water action. 

 It is, therefore, a fair presumption that large lakes 

 have covered much of its present deserts, and that 

 they have dried up by the operation of the same 

 changed climatal conditions as those which have 

 reduced the Caspian and the Dead Sea to their 

 present dimensions. 1 



Thus it would seem that the Euphrates valley, 

 the centre of the fabled Noachian deluge, is also 

 the centre of a region covering some millions of 

 square miles of the present continents of Europe, 

 Asia, and Africa, in which all the facts, relevant 

 to the argument, at present known, converge to 

 the conclusion that, since the miocene epoch, the 

 essential features of its physical geography have 

 remained unchanged ; that it has neither been 

 depressed below the sea, nor swept by diluvial 



1 An instructive parallel is exhibited by the "Great Basin" 

 of North America. See the remarkable memoir on Lake 

 BminewlU by Mr. G. K. Gilbert, of the United States 

 Geological Survey, just published. 



