Reviews — Prof. Hull's Survey of Palestine. 231 



in volume of the Mediterranean Sea — whether both originate from a 

 common cause is not stated ; but whilst the reduction of the Mediter- 

 ranean is inferred to have taken place " at an epoch not very remote 

 and which may be represented by the Interglacial stage of the 

 Quaternary period," the reduction of the Dead Sea is placed further 

 back, at the beginning of the Pliocene. 



The next stage in the geological history of the Dead Sea to which 

 the author introduces us is that of "The Pluvial Period (Pliocene 

 and Post-Pliocene)," in which there was a general subsidence of the 

 whole region bordering the Levant and a general rising of the 

 inland waters, till the Jordan- Arabah depression was filled by a 

 lake (fresh- water ?) over 200 miles in length and over 2000 feet in 

 depth. This great change appears to have been produced by the 

 climate of the Glacial period, when the temperature of Palestine is 

 stated to have been 25° Fah. lower than at present, and the climate 

 resembled that of the British Isles. But the Dead Sea basin even 

 then was not filled to the brim, and it would at that time have 

 required no small engineering capacity to have cut a canal through 

 the water parting in the Arabah valley, to unite its waters with those 

 of the Red Sea. 



Subsequently to the Pluvial period we are told by the author that 

 the more modern physical conditions set in, and by gi-adual degrees 

 the waters in the Dead Sea basin were for a second time reduced to 

 the low level now existing. 



The author devotes a special chapter to the "Origin of the Saltness 

 of the Dead Sea," from which it appears to be his opinion that it is 

 merely owing to the concentration by evaporation of the saline 

 ingredients which the rain-water of rivers and streams has dissolved 

 out of the strata through which it passes. 



The author makes the following novel comparison between the 

 water of salt lakes and that of the ocean : " It is probable that the 

 water of the ocean itself has become salt owing to the same cause 

 which has produced saltness in the inland lakes, as it may be re- 

 garded as a mass of water without an outlet." It is, however, 

 arguing in a circle to attribute the saltness of the ocean to the land, 

 whilst the land itself, including the salt (leaving eruptive rocks out 

 of the question), may be attributed to the ocean. 



The author makes no allusion to what has become of the enormous 

 mass of solid materials which has been removed from the surface of 

 the drainage area of the Dead Sea, and carried into its basin. Some 

 of it is, of course, represented by the terrace deposits, but we can 

 hardly account for the rest, without supposing that the depression 

 of the Dead Sea has originally been much deeper than it is now, 

 and that it has been partially infilled. 



In an appendix Mr. F. W. Rudler describes the microscopio 

 structure of the specimens of crystalline rocks collected by Prof. 

 Hull in Arabia Petrasa. 



The work is illustrated by two geological maps and by numerous 

 sections and profiles which show very distinctly the stratigraphical 

 relations both of Palestine itself and the Sinaitic peninsula. 



