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HUDLESTON: GEOLOGY OF PALESTINE. 
6. Beds of marine origin newer than the N'ummulitic limestones. — 
Beds with Miocene fossils I have already stated as occurring in the 
Chalouf cutting" of the Suez canal, but whether the whole of the 
district marked b in the map, is to be regarded as Miocene is ex- 
tremely doubtful. Yet the hollow or depression of the Isthmus of 
Suez, is, in part, filled in by Miocene beds, and it is probable that 
since Miocene times, there has been no communication between the 
Red Sea and the Mediterranean, notwithstanding the very sHght 
water shed. It is said that not a single species is common to the 
Mediterranean and the Red Sea, whose fauna belongs to the Indian 
Ocean. The Red Sea fauna extends up to the basin in which the 
Bitter Lakes are situated ; and the Mediterranean fauna is traced 
southward for some distance, but they never meet. A portion of the 
intervening ground between Lake Timsah and Serapeum is occupied 
by freshwater beds, which show that a branch of the Nile, most likely 
in Quaternary times, flowed through the hollow now occupied by 
the sweet water canal, past Tel-el-Kebir and Ismailia, where it most 
probably turned round into the Red Sea. The Etherias of the Nile, 
now confined to the cataract districts and above, are found in abund- 
ance in these deposits near Serapeum. Etheria, I may mention, is 
a peculiar genus of the family Unionidee, very characteristic of some 
of the great African rivers. 
Most of the coast deposits in the great bight which lies between 
Mount Carmel and the delta of the Nile, are regarded by liartet 
as Quaternary and recent. 
7. The Volcanic Rocks. — Under this head I would only include the 
Tertiary eruptions, interpreting the word Tertiary in its widest 
sense, as coming down to the present time. Mr. Bauerman concluded 
that the volcanic rocks of that portion of the Sinai peninsula visited 
by him were of two periods, of which the second was contemporary 
with the flint conglomerate. 
The twenty-eight harrahs of Arabia, in alignment with the Red 
Sea, the Gulf of Akabah, and the Dead Sea hollow, are remarkable 
instances of the parallelism of volcanic centres to fissures filled with 
water. I should mention that ' a harrah means a fire district or 
volcanic region. One of these, not far from Medinah, erupted 
