Yol. 51.] COMMUNITY OF FISH-SPECIES IN KILE AND JORDAN. 



93 



9. On the Physical Conditions of the Mediterranean Basin which 

 have resulted in a Community of some Species of Freshwater 

 Fishes in the Nile and the Jordan Waters. By Prof. E. Hull, 

 M.A., LL.D., F.B.S., F.G.S. (Read February 6th, 1895.) 



[Abstract.] 



The Author summarizes the evidence in favour of the existence 

 of barriers in post-Miocene times, separating the Mediterranean 

 area into a chain of basins. He brings forward arguments in 

 support of his contention that the waters of the eastern (Levantine) 

 basin became fresh during a period when the area of evaporation 

 was smaller, and the supply of river-water greater, than at present. 

 Into this freshwater lake the waters of the Nile would flow directly. 

 He has elsewhere given reasons for believing that the Jordan Valley 

 from Late Huleh to Arabah was the bed of a lake over 200 miles 

 long, and at least 1300 feet above the present level of the Dead Sea. 

 He suggests that the waters of this lake escaped into the Levantine 

 basin through the plain of Esdraelon. With such physical con- 

 ditions existing, the fauna of the Levantine basin would have a 

 means of spreading throughout the whole system of waterways 

 connected with it. 



In conclusion the Author adds some observations on the changes 

 which occurred in the Mediterranean area subsequent to the post- 

 Miocene epoch of earth-movement. 



Discussion. 



Dr. Blanford thought that the distribution of marine Upper 

 Tertiary beds in the Eastern Mediterranean area was not in 

 accordance with the Author's theory. He especially drew attention 

 to the well-known marine Pliocene beds of Italy, Sicily, and Greece. 

 Moreover, if the hypothetical freshwater lake in the Levant 

 accounted for the presence of Chromididse in the Jordan, in 

 Asia Minor, and in Tripoli, how was their absence in all European 

 rivers that run into the Mediterranean, the Black Sea, and the 

 Caspian to be explained '? 



Dr. Gregory said that the paper raised several interesting questions 

 and carried us back to some ancient authorities. The Author's 

 theory assumed, and was proposed to explain, the introduction 

 of the Jordan fish-fauna from the Mediterranean. But there 

 was only one species (a blenny) common to the two, and the 

 faunas were as different as they could well be. He quoted 

 Dr. Gunther to show that the difficulty in regard to the origin of 

 the Jordan fish-fauna is that it contains a group of forms which 

 are absent from N.E. Africa. This, the real difficulty, was appa- 

 rently not appreciated by Prof. Hull. The speaker showed that the 

 evidence of other groups was of the same character. He thought 



Q. J. G. S. No. 202. 1 



