173 



to the operations of a current setting in that direction, 

 and by \vhich they were torn up from the bottom and 

 thrown upon the surface of that kind of Valley, at the 

 foot of the eastern slope of the Alps ? No appearances 

 of the kind have ever, I believe, been taken notice of 

 on the opposite shores of that sea ; neither have the 

 shells, mentioned by Dr. Shaw, as being spread 

 over Egypt, the families of which are still living in the 

 Red Sea, ever been observed on the eastern borders of 

 that sea, or the Arabian deserts. It is true Mr. Irwin 

 mentions, that quantities of shells, are found in the de- 

 sert near Mocha, but he likewise says, that they are 

 the productions of the Ocean.* 



That the shells in both these instances were removed 

 by the force of currents from the south, lhave no doubt, 

 and this opinion is supported by similar facts, that oc- 

 cur in other parts both of Europe and Asia, where not 

 only like cases occur, but they seem decidedly, to have 

 been produced by the same cause, and most probably, 

 at the same time. 



In the immense deserts, at the northern extremity, 

 of the Caspian Sea, numerous instances of this kind are 

 to be seen, and of which Pallas has made particular 

 mention in his travels in Russia. 



< We have" he observes, " the following incontes- 

 tible proofs, that the Yaikian desert, as well as those of 

 the Kalmuks, and the Wolga, have been formerly cov- 

 ered by the waters of the Caspian Sea : first, the innu- 



Mrwin's Voyages, vol. 1 p. 18. 



