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, differing from those of 
the surrounding 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 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. Vol. in. x 
