258 EAST AFRICAN FLORA AND FAUNA part in 



the Jordan basin. An incomplete connection such as this 

 would allow the fish to pass b}^ the Wadi Arabah route ; but 

 the evidence, geological and geographical, renders an actual 

 outlet from the Jordan over this pass so probable, that it is 

 simpler to accept it. We may therefore assume that a river 

 flowed southward from Palestine, and along that part of the 

 Rift Valley which is now occupied by the Red Sea, and 

 entered the Indian Ocean somewhere near Aden. Near its 

 mouth this Erythrean River (for it may conveniently be 

 called after the ancient name of the Red Sea) probably united 

 with another from the highlands of Central Africa, which 

 flowed along the Rift Valley from the northern end of Basso 

 Narok (Lake Rudolf),^ following the course of the Omo 

 and Hawash, and across the depressed basin of Afar. This 

 river would have received the drainage of the southern slopes 

 of Abyssinia, the Rift Valley between Naivasha, Baringo, and 

 Basso Narok, and also of the Victoria and Albert Nyanzas, 

 which were not then connected with the Nile. At this time 

 the Nile itself probably rose on the northern slopes of the 

 mountains of Latuk on the east bank, and of Kakuak on the 

 west, and the drainage of the two Nyanzas passed to the south of 

 this mountain range, along the valley of the Musanyi, through the 

 Salisbury lake-chain, and down the Turquell into Basso Narok. 

 At this time, then, we may assume that the equatorial 

 lakes were in direct river communication with the Jordan, 

 and their fish could reach Palestine without entering 



1 Dr. Donaldson Smith's very successful expedition across Somaliland to Basso Narok 

 has thrown further light on the possible connection between the Onio and that lake. 

 Dr. Smith, in a paper read before the Geographical Society on 6th January 1896, has 

 expressed his doubts as to this connection ; he regards the Omo as one of the head- 

 streams of the Juba, and thinks that the Basso Narok depression ends off in the moun- 

 tains in southern Abyssinia. If that is the case, there cannot have been any former outlet 

 from Basso Narok to the north-east. But Borelli traced the Omo to a level (3450 feet) 

 which renders its connection with the Juba almost impossible, and all the information given 

 him by natives was in favour of the Omo reaching a great lake. The altitudes given by 

 Dr. Smith to Lake Abbaja render it just possible that the Omo reaches this lake instead' 

 of Basso Narok. On Dr. Smith's preliminary map (issued 6th January) two scarps with 

 a depression between them are indicated. The western scarp is only shown to the west 

 of the head of the Nianam ; but the occurrence of an apparent continuation of this to the 

 north-east has been shown by previous explorers. The eastern scarp is marked from 

 Fakes to Amara, and the altitudes given render its continuation past Basso Ebor to Basso 

 Narok most probable. This leaves the Zuai lake-chain, the Omo valley, and the country 

 between Borelli's southernmost point on the Omo and Dr. Smith's most northern point on 

 the Nianam, on the iloor of the depression. Dr. Smith's exploration therefore appears 

 to me to confirm the idea that the Omo and Lake Rudolf are connected by a line of 

 depression. 



