200 T. F. Jamieson — Inland Seas of the Glacial Period. 



the other to drain into it. This would wash the salt out of the 

 Eastern lake and freshen its waters — that is to say, if it had an over- 

 flow. From Admiral Spratt's chart/ it appears there is a deepish 

 narrow channel across the submarine ridges between Sicily and 

 Africa, which may perhaps indicate the course of the river that flowed 

 out of the Eastern lake. But as the evaporation would be consider- 

 ably stronger in the eastern area, seeing that it lies farther inland 

 and more to the south, possibly no overflow would take place. Not 

 many years ago it was often stated that the Sahara desert was occu- 

 pied by the sea during the Quaternary period. Had this been the 

 case it would of course have tended to render the air in its vicinity 

 moi'e humid, and have lessened evaporation over the adjoining parts 

 of the Mediterranean ; but this notion of a late submergence of the 

 Sahara has not been sustained by more recent investigation, and it is 

 now believed to have been dry land. Karl Zittel, in his " Contribu- 

 tions to the Geology and Palf^ontology of the Libyan Desert " 

 (Cassel, 1883), says that during the Quaternary period (Diluvial 

 Zeit) the Sahara, as well as a portion of the southern and eastern 

 area of the Mediterranean, was dry land.^ The desei't sand results 

 from the decomposition of the sandstone which forms the prevailing 

 rock througliout the Central and Southern Sahara, and its distxibu- 

 tion and heaping up into dunes have been efi'ected by the wind. 

 Among the Quaternary deposits may be mentioned beds of calcareous 

 tufa in the oasis of Chargeh, containing reeds and leaves of Quercus 

 ilex, a tree which now grows in Southern France and Corsica. 



If the eastern portion of the Mediterranean — the Levant — had 

 been isolated by the elevation of a ridge of dry land connecting 

 Italy with Tunis, and the evaporation not been sufficient to keep 

 down the water in that basin, then it would have risen until it 

 escaped over the low ground at the Isthmus of Suez into the Red 

 Sea, But I am not aware of any evidence, geological or otherwise, 

 to show whether this has occurred during the Quaternary period. 



The drying up of the Mediterranean would re-act upon the 

 climate of Southern and Central Europe and cause it to be drier, so 

 that less water would flow from thence into the basin, and this 

 would tend to lower the inland sea still more. 



Prof. Boyd-Dawkins, in his interesting book on " Cave Hunting," 

 speculates on a former elevation of the Mediterranean basin — 

 greater even than that suggested by Ramsay and Geikie — as being 

 necessary to account for certain facts he mentions. But an upheaval 

 of the whole area of this large sea seems too violent a hypothesis, 

 and is unnecessary. All we want is to shut out the Atlantic, and 

 evaporation will then do the rest that is required by drying up the 

 water. 



' Quart. Journ. Geol. Soc. vol. xxiii. p. 293. 



2 See also A. Pomel, Bull. Geol. Soc. of France, for 4th Feb. 1878, 3rd ser. vol. 

 vi p. 223, and M. Tournouer, ib. p. 619. 



Ellon, Aberdeenshire. 



