126 THE DESICCATION OF LATER GEOLOGICAL TIMES. 



Journal of the Royal Geographical Society,* to the discussion of the physical 

 changes going on in the Aralo-Caspian Basin. 



To sum up the results attained by these and other investigators, it may be 

 stated that there is no doubt of the former vastly greater extension of the 

 combined Aralo-Caspian Seas, and extremely little as to their former connec- 

 tion witli the Polar Ocean. While there has been much discussion, without 

 absolute unanimity of opinion having been attained, in regard to the shifting 

 channels of the rivers entering these seas, and their variations of volume at 

 different times during the historic period, it seems to be beyond dispute that 

 a gradual desiccation, extending over a vast area, has been, and still is, in 

 progress. 



Dr. Neumayr, in a notice of Professor H. Schmidt's work on the Aralo- 

 Caspian depression,! gives the following statement as the result of his inves- 

 tigations of this subject. t "The solution of this enigma is offered by the 

 study of the Tertiary formations of Eastern Europe and Western Asia. As is 

 well known [bekanntlich], thex'e existed, in later Miocene times, an immense 

 slightly brackish inland sea, which included the basins of Hungary and 

 Vienna, Transylvania, Wallachia, Croatia, Sclavonia, the Black Sea, the 

 Pontus, the larger portion of the Grecian Archipelago, and the Aralo-Caspian 

 Basin. At a still eai'lier epoch the region thus embraced was an immense 

 gulf of the Northern Arctic Ocean, from which the basin in question became 

 gradually separated. The freshening of the arm of the sea thus cut off from 

 communication with the salt water became possible, as may be atHrmed with 

 almost certainty [ziemlicher Bestimmtheit], by means of an outlet in the 

 direction of the upper course of the Irtysch and Obi Rivers. This immense 

 brackish-water basin has been, ever since later Miocene times, in the condi- 

 tion of continuous decrease in size ; and the intercalation of the glacial 

 epoch had no effect, so far as has been yet made out, in raising its level. 

 The separation between the Black and the Aralo-Caspian Seas must have 

 taken place before the former became connected with the Mediterranean, 

 as is shown by the small amount of saline matter in the Caspian; and the 

 union of the Black and the Mediterranean Seas must be of very recent 

 date, since the detrital deposits on the borders of the Black Sea contain 



* See Journal of the Royal Geographical Society, Vol. XLV. (18"5), p. 367, Art. XV., entitled " Notes on the 

 Lower Amii-darya, Syr-darya, and Lake Aral, in 1874." By Major Herbert Wood, E. E. 

 + Prof. Dr. H. Schmidt, "Die Aralo-Kaspi Niederungund ihre Befunde." Leipzig, 1874. 

 t Verhaiidlungen der k. k. geol. Keichsanstalt, 1875. p. 31. 



