318 



On the Fauna and Flora of Palestine. 



[Apr. 23, 



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

 a series of forms of Ufe in all classes, differing from those of the surround- 

 ing region, to which they do not extend, and having Ethiopian and, more 

 strictly, Indian affinities. 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 representative, this law, that climatal zones of life are mutu- 

 ally repeated and represented by elevation or depression and latitude, would 

 account for their existence. 



But we have a transjported flora ; this negatives the idea of an indepen- 

 dent 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 isolation 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 before the glacial epoch in its present form, when 

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

 fauna and flora had a more northerly extension. This would be contempo- 

 raneous with the miocene continent of Atlantis, and the Asturian flora of 

 South-west Ireland. 



Palestine would then be East African. Aftervv^ards the glacial inroad 

 would destroy the mass of preexisting life, excepting the few species most 

 tenacious of existence which survive in the still comparatively warm de- 

 pression of the Jordan valley, which thus became a tropical outlier," ana- 

 logous to the boreal marine outliers of our own seas. The Indian types are 

 explained by the former continuous miocene continent from India to 

 Africa. The peculiar species may either yet be found in Arabia, or, if not, 

 may be descendants of species which inhabited the country with a limited 

 range, or may be variations stereotyped by isolation. 



The peculiar fishes of the Jordan are most important, dating probably 

 from the earliest period after the elevation of the land. The genera of the 

 peculiar species are exclusively African, v/hile the species are representative 

 rather than identical. We may explain this by the miocene chain of fresh- 



