284 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [Jan. 4, 



inference that these deposits are impregnated with salts, either of 

 mineral or marine origin : — such as the uncertainty of obtaining 

 drinkable water from wells sunk in many parts of the Steppe ; also 

 the growth, in some localities, of certain saline plants from which an 

 alkali is obtained ; the fact also that only certain trees will flourish 

 on that part of the Steppe where the earthy marls of the drift 

 alone form the surface. Several mineral-springs also, of consider- 

 able medical repute, I believe, are known to exist in the Princi- 

 palities. 



This saline property may, however, not be due to purely marine 

 salts, but to some mineral solutions that were set free from volcanic 

 or other subterranean sources during the final destruction of the 

 great Oriental Lake, the existence of which is identified by groups 

 No. 1 and No. 2. The existence of this old lake, therefore, may be 

 said to be traceable to a period immediately before the present Black 

 and Caspian Seas changed from fresh to salt. 



This superficial drift, indicating the presence of saline matters, 

 may indeed be the result of depositions that occurred during that 

 transition-period, and thus may indicate that during that event there 

 was a sudden admixture of a large body of sea-water with the lake, 

 which probably, I think, rapidly subsided to the level of the Medi- 

 terranean, being now brought into connexion with it by the opening 

 of the Bosphorus, brought about by the general volcanic disturbance 

 that apparently then took place. For great upheavals must have 

 occurred about this period, as shown at Baljik by the high elevation 

 at which the corresponding freshwater deposits and relics of the drift 

 are now found, namely, about 600 feet above the sea. From this 

 height they gradually incline towards the valley of the Danube, or 

 rather towards the north, — just as the Bessarabian deposits gradually 

 incline towards the south. But the lake may probably at the latter 

 period of its existence have stood at a much higher level than the 

 present sea, as conjectured in former papers. 



If this be the true explanation in respect to the origin of the 

 superficial deposits or drift, then the body of sea- water thus suddenly 

 thrown into the lake must have come from the north, by the up- 

 rising of some large portion of Russia, as has before been conjectured 

 by some of our most eminent geologists in accounting for the origin 

 of the drift ; — that is, on the supposition that the superficial earthy 

 marls constituting group No. 3 of the Steppe-series is a real drift, 

 or a deposit formed during the change of the lake into a brackish or 

 salt sea ; and I have seen no recent deposit, either as a member of 

 the superficial marls or otherwise, that indicates, by evidence of 

 fossil shells, a long tranquil period of brackish water conditions. 



I lean also to the opinion that the lake was not long at a higher 

 level with brackish water, or in a transitional state, from the fact 

 that a communication apparently existed about this time between 

 the Black Sea and the Sea of Marmora by the Buyuk Tehekmejeh 

 Valley, which is, I believe, nowhere more than a few feet above the 

 present level of the Black Sea, and consists of a chain of lakes, 

 marshes, and alluvial soil. 



