142 THEORY OP THE EARTH. 



have been made. The alluvial depositions of these 

 rivers, in the course of 2250 years since the time 

 of Herodotus, have reduced the sea of Asoph to its 

 present comparatively small size; have shut up 

 entirely that branch of the Dneiper which formerly 

 joined the Hypacyris, and discharged its waters 

 along with that river into the gulf called Carcinitcs, 

 now the Olu-Dcgnitz ; and have now almost reduced 

 the Hypacyris and the Gerrhus to nothing.* 



We should possess proofs no less strong of the 

 same thing, could we be certain that the Oxus or 

 Sihon, which flows at present into Lake Aral, for- 

 merly reached the Caspian sea : But the proofs 

 which we possess on all these points are too vague, 

 and even contradictory, to be admitted in support 

 of physical propositions, and besides, we are in 

 possession of facts sufficiently conclusive, without 

 being under the necessity of having recourse to 

 those which are doubtful. 



The downs or sand-hills which are thrown up 

 by the sea upon low flat coasts, when the bed of 

 the sea happens to be composed of sand, have been 



* See the Geography of Herodotus by M. Rennel, and the Physical 

 Geography of the Black Sea, fcc. by M. Bureau de la Halle. 



In the latter work, p. 170, M. Bureau supposes Herodotus to have 

 said that the Boristhenes and the Hypanis flowed into the Palus 

 Meotis: But Herodotus, in Melpomene, LIII. only says that these two 

 rivers discharged their waters into the same marsh; that is, into the 

 Liman, exactly as in the present day ; and Herodotus does not carry 

 the Gerrhus and the Hypacyris any farther. 



