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Geological Remarks upon the Neighbourhood of the Caspian 

 . ,. Sea. By M. Eichwald of Wilna. 



X HE Caspiap Sea, as regards Natural History, offers to view 

 many peculiarities, which at once mark it out from all other 

 lakes. Indeed its astonishingly low level, which is shewn to be 

 below that of the Black Sea, and consequently under the level 

 of the ocean, prove it to be a lake which lies 717,817 French 

 feet deeper than the Sea of Aral. But, as the frequently unfa- 

 thomable depth of the Baikal Lake, which is surrounded by 

 lava and other volcanic masses, seems to be occasioned by the 

 volcanic structure of its bed ; so may a similar structure in part 

 sufficiently account for low level, and the very considerable depth 

 of particular parts of the Caspian Sea. This sea might gradual- 

 ly sink, from the powerful evaporation necessarily caused by 

 the warmth of the chmate ; while the supply of water from few 

 rivers could not balance the powerful evaporation. 



But since many of the shores of the Caspian^ particularly the 

 east coast, at the bay of the Balchan, display numerous masses 

 of burnt porphyry, and even lava ; and since pseudo-volcanic 

 causes are now existing in operation on the west coast, near 

 Baku ; so we at once see that great subterranean cavities must 

 be thus formed, which would draw off the water, and conse- 

 quently lower the surface of the lake. The two porphyry masses 

 of Kasbek and Elbrus, which exceed in height the summit of 

 Mont Blanc, as well as the whole Caucasian chain, which is 

 of a volcanic nature, lead us to expect, from their formation, a 

 considerable lowering of the level of the Caspian Sea ; since, du- 

 ring their formation, subterranean apertures must have been 

 formed, into which the waters of the sea would gradually retire. 



Likewise, the Caspian Sea is distinguished by the great quan- 

 tity of salts which it holds in solution, particularly sulphate of 

 magnesia, by means of which the water will be unpalatable, 

 and doubtless prejudicial to animal life. The water of the 

 Black Sea, it is true, seems to be still Salter ; but it is not so 

 bitter, because it contains mostly muriate of soda ; while the 

 water of the Caspian Sea is strongly impregnated with sulphate 

 of magnesia. Hence it comes to pass that the former sea abounds 



