152 PROF. E. HULL, LL.D., F.R.S., F.G.S., ON 



amongst the mountains of the Lebanon from Avhich they are 

 now altogether absent.* 



To this objection there may be offered two very forcible 

 answers. First. — It may be confidently asserted that a 

 general lowering of the temperature and change in the 

 climate of Western Europe would necessarily produce some 

 effect in the same direction on the regions lying beyond. If the 

 climate of Scandinavia, of the British Isles, of France, Spain 

 and Portugal became sensibly more rigorous, it is clear that 

 owing to the circulation of the air currents, the climate of 

 the adjoining regions to the eastward would also experience 

 at least a proportionate change in the same direction owing 

 to the greater accumulation of ice and snow in the higher 

 altitudes. It is impossible to say to what distance this 

 influence would extend, and did extend during the Pleisto- 

 cene period ; especially during the epoch of maximum cold. 

 I think it may safely be assumed that none of the regions 

 above enumerated were altogether unaffected by it ; and for 

 my own part I am inclined to believe that the entire northern 

 hemisphere felt the loss of heat due to the diminution of 

 temperature of the Gulf Stream. 



Second. — But there remains a still more potent cause for 

 the greater prevalence of glacial conditions than is the case 

 at present in the regions refeired to. It is well-known that 

 towards the close of the Pliocene period the vast tract 

 embracing the basin of the Mediterranean and adjoining 

 regions extending eastward was undergoing gradual changes 

 as regards the relations of land and sea. After a slight 

 depression — during which sea-beaches were formed along 

 the old coast lines in the lands bordering the Levant, there 

 ensued a process of elevation ultimately resulting in the con- 

 version of the Mediterranean basin into a chain of fresh- water 

 lakes connected by rivers with the Black Sea and Caspian, and 

 closed against the influx of the Atlantic waters by the uprise 

 of the sea-bed at the Straits of Gibraltar. At this period 

 Sicily was connected with Malta and Tunis, while the island 

 was inhabited by elephants and hippopotami, as shown by 

 Leith Adams and Spratt. The two lakes thus formed were 

 connected by a river channel crossing the " Medina Bank," 

 which is now submerged to a depth of 250 fathoms-t 



* Hooker, On the Cedars of Lebanon, Nat. Hist. Rev., 1862 ; also. Sir 

 W. W. Smyth, Pres. Address Geol. Soc. (1868), Quart. Journ., vol. xxiv, 

 p. r)8. 



t Spratt, Quart. Journ. Geol. Soc, vol. xxiii, p. 292. 



