HUDLESTON: GEOLOGY OF PALESTINE, 
207 
probable age of its deposits, including- of course those of the Wady 
Arabah, and see how far their history bears on the question of the 
sudden sinking* of the Dead Sea basin, which has been supposed 
by some to have been the cause of the ruin of the five cities. 
Now M. Lartet maintains that the great fissure has been an 
independent basin for a long period, indeed, at one time he was 
disposed to regard its origin as having dated from Miocene times, 
but in his latest work La Mer Morte, he does not seem disposed 
to carry it so far back in time. But that it has been an independent 
basin for an immense period, he considers can be shown in many 
ways. Firstly, as was noticed by Hitchock, from the surveys of 
Robinson and Smith, all the tributaries of the Arabah flow in so as 
to form an acute angle with the main valley pointing to the north, a 
very strong physical proof that the drainage of that region has not 
been reversed. On the other side of the Dead Sea the lateral wadies 
of the Jordan S3^stem for the most part point to the south ; all the 
evidence indicating that the drainage has been towards the Dead 
Sea in former times just as it is now. 
But in spite of these facts, so ably put forward by Hitchcock 
and Lartet, it must be admitted that the zoological evidence does 
point to the probability of some connection, doubtless of very high 
antiquity, with an African continental river system. Canon Tris- 
tram, with his usual energy, brought to England numerous specimens 
of fish from the upper waters of the Jordan system, probably from 
the lake of Tiberias. Some of these were decidedly of African types. 
According to Dr. Gunther the following genera occur, viz. : Chromis, 
Hemichromis, and Clarias. Now Clarias macr acanthus is a common 
fish of the upper Nile. But to show the remote nature of the con- 
nection, it is a curious circumstance that Hemichromis in not repre- 
sented now-a-days in N.E. Africa, but chiefly in the central African 
lakes and even in the west coast rivers. 
On the whole, Dr. Gunther, who had the examination of Tris- 
tram's fishes, demurs to M. Lartet's notion as to the complete 
independence of this valley system. Nevertheless, an examination 
of the nature and mode of occiu'ence of the Jordan valley deposits, 
as shown both by M. Lartet and Captain Conder, prove the very 
