36 Proceedings of the Royal Physical Society. 



much simpler explanation to refer their origin to deposition 

 from the Dead Sea itself, which took place at a time when the 

 level of that water was much higher than it is at present. 

 That would mean that the rate of evaporation going on at 

 that part has long been slightly in excess of the supply 

 carried in by the Jordan. For the rest, so far as the salt is 

 concerned, the only other factor needed is that of time. But 

 as Bischof pertinently remarked in this connection many 

 years ago {Ghem. Geol., Engl, trans., vol. i. p. 86) : If a 

 river carries in solution go^oo of a given constituent ... it 

 will transport in 8000 years a quantity as great as that of 

 the water it annually conveys. " But what are 8000 years 

 compared with geological periods, in which we must reckon 

 millions of years ? " 



As regards the Jordan- Arabah depression, in which the 

 Dead Sea lies, I may remark, in passing, that there has been 

 no reason advanced yet by anyone to prove that this remark- 

 able depression may not be the outward expression of a 

 terrestrial fold. There has been no proof given that there is 

 any fault there, although it has been repeatedly inferred that 

 one exists. It is just as likely that the depression is simply 

 a geo-synclinal, correlative with the geo-anticlinal upon 

 which Jerusalem is situated. I have long taught in my 

 lectures that the Jordan-Arabah depression is simply one of 

 a series of earth-folds which have affected a large part of the 

 Orient, from Egypt eastward. The Nile Delta is situated 

 over one of the zones of depression.^ Probably it will some 

 day be demonstrated that the entire series of surface folds is 

 in process of formation even at the present day. 



[The substance of the foregoing remarks may here be 

 fittingly summarised, and in doing so I shall take the liberty 

 of reprinting a paragraph which was published in the Proc. 

 Boy. Phys. Soc, vol. xiv. pp. 184, 185 (read January 18, 1899, 

 published in December of the same year), in a paper by 

 myself " On the Genesis of some Scottish Minerals " : — 



^ It may some day be proved that all deltas coincide with zones of 

 contemporaneous depression. See Trans. Geol. Soc. Glasgow, vol. for 1902, 

 in this connection. 



