Rev. H. B. Tristram on the Fauna and Flora of Palestine. 65 



are modifications of desert types in the south, and of Mediterranean 

 forms on the coast. Variation in this class appears rapidly to follow 

 segregation, as shown by the Jordanic species. The fluviatile mol- 

 lusca are much more distinct, and indicate a very ancient separation 

 from any adjacent district. 



Similar inferences may be drawn from the examination of the 

 Arachnida, Lepidoptera, Hemiptera, and Orthoptera, as well as 

 from the Rhizopod fauna, which is similar to that of the Indian 

 Ocean. (The examination of the Coleoptera is not yet completed.) 



The flora of Palestine is, on the coastline and highlands, simply a 

 reproduction of that of the Eastern Mediterranean. That of the 

 Jordan valley is most distinct. Of 113 species by the Dead Sea, 

 only 27 are European, and these chiefly weeds of world-wide distri- 

 bution. In this area the flora is almost exclusively Ethiopian, con- 

 sisting largely of species extending from the Canaries to India. 



Thus in the Dead-Sea basin, an area of but a few square miles, 

 we find a series of forms of life, in all classes, difl'ering from those of 

 the surrounding region, to which they do not extend, and having 

 Ethiopian and, more strictly, Indian aflinities. The basin is depressed 

 1300 feet below the sea-level; and as zones of elevation correspond 

 to parallels of latitude, so here a zone of depression represents the 

 fauna and flora of a low latitude. If the flora were reitrcsentative, 

 this law, that climatal zones of life are mutually repeated and repre- 

 sented by elevation or depression and latitude, would account for 

 their existence. 



But we have a transported flora ; this negatives the idea of an 

 independent origin on the spot. The theory of migration, under 

 present conditions, is refuted by the coexistence of peculiar and 

 unique forms with others now found in regions widely apart. Of 

 these, the physical character, and the phenomena of their present 

 distribution, present insuperable obstacles to their migration under 

 existing geological conditions. 



Their existence must be mainly due to dispersion before the isola- 

 tion of the area ; this must have been after the close of the Eocene 

 period, to which belong the most recent superficial deposits of 

 Southern Palestine. There are no beds synchronizing with the 

 miocene deposits of Sicily &c. ; it must have had a fauna and flora 

 contemporaneous with the miocene flora of Germany. There is 

 geological evidence that since the Eocene period the Jordan fissure 

 has had no connexion with the Red Sea or Mediterranean. There 

 are subsequent vast marl deposits of the Dead Sea when it was at a 

 higher level ; but they are wholly unfossiliferous. The diminution 

 of the waters may, for reasons given, be fixed about the close of 

 the tertiary epoch. We have also evidence of the extension of the 

 glacial period thus far south, as in the moraines of Lebanon. 



Still the lake existed in its present form before the glacial epoch, 

 when there was an unusually warmer climate, and the more antique 

 Ethiopian fauna and flora had a more northerly extension. This 

 would be contemporaneous with the miocene continent of Atlantis, 

 and the Asturian flora of South-west Ireland. 



Ann. & Mag, N, Hist. Ser. 4. TW. ii. 5 



