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Oena and the Red Sea coast from Safaga to Qosseir. They are of great thick- 
ness at the base of Gebels Abu Had (at least io5 metres) and Serrai, outlying 
hills easily visible from Qena. They also reappear in the faulted regions near 
Qosseir and Safaga (Gebel Duwi, Wadi Barud, Mohammed Rabah, etc.). These 
strata have not been systematically examined for nitrates, but from experience 
in the valley must be regarded as worthy of closer study for these salts. 
Dr. Ball also informs me that he has noted the same strata with similar 
characters in Western Sinai, an interesting point being the existence of 
nitrates in them. No nitrates have hitherto been proved to my knowledge in 
the Eastern Desert of Egypt east of the Red Sea watershed; a sample of shale 
brought by Mr. Murray from Gebel Beida, near Qosseir, and analysed in the 
Survey Department Laboratory yielded 8.28 ojo of Sodium Sulphate and 
0.91 0/0 of Sodium Chloride, but no nitrate. 
SUMMARY REGARDING NITRATES IN EGYPT. 
The following facts must be borne in mind in framing any theory as to the 
origin of Nitrates in Egypt : 
1. Tlie Nitrate Shales of Egypt occupy a very definite geological position, 
being at the summit of the Cretaceous beds, and immediately below strata of 
definite Lower Eocene age. 
2. They are well developed between lat. 96° and 27° N. from Farafra 
Oasis on the west, to the Phosphate mining regions on the borders of the 
Red Sea near Qosseir and Safaga. 
3. The evidence available points to these strata having been formed under 
deep-water conditions. Thus they are spread over wide areas without material 
change in character, are connected with white limestone containing fossil sea- 
urchins and sponges, the nearest relations of which at the present time live in 
deep seas. The fauna found in them also consists of small corals, univalves 
and bivalves quite dilTerent from those of shallow-water strata, and there is 
in general an absence of coarser sandy material. 
A. The wide distribution of the Nitrates in the shales suggest that they are 
of original formation in them, rather than brought in at a later date. 
