— 153 — 
It is evident that if the Nitrate Shales in Egypt possessed even low per- 
centages of nitrate, it would be possible to enrich tlie salt content by lixiviating 
with water at a high temperature. Unfortunately, the main difficulty is not the 
low percentage, but the irregular distribution. 
Ill 
DISTRIBUTION OF NITRATE SHALES IN UPPER EGYPT. 
The most important work in this connection has been done by Messrs. Barron 
and Beadnell, of the Geological Survey of Egypt. The following remarks as 
regards details are largerly based on their report, with additions from personal 
experience. 
The Nitrate or Tafla beds consist of thin laminated shales, usually of grey 
or green colour, often purple near the base, and containing numerous minute 
veins of calcareous material crossing each other at all angles. Nodules of oxide 
of iron occur throughout, and in some places thin beds of a sandy ironstone are 
present, while thin glistening deposits of Sodium Nitrate, Sodium Chloride, 
etc. follow the bedding and joint-planes of the shales. The amount of nitrate 
is certainly very variable, many places not being considered worth working 
by the natives. These strata occur at the base of the great mass of limestone 
of Lower Eocene age which forms the high clitî bordering the Nile Valley on 
the west, while on the eastern side they are displayed in the lower foothills 
between Qena and Mahamid, and also at the base of tiie higher hills near 
Armant, Schagab, etc. 
The full geological succession as determined by the present writer ^'^ on the 
east bank of the Nile opposite Esna is as follows, beginning from above (see fig. i). 
EOCENE STRATA. 
1. Biscuit-coloured Lower Eocene Limestone with Operculina lihyca, 
ScHWAGER, in abundance. Also numerous sea-urchins {^Conoclypeus Delanouei, 
DE LoRiOL, Rhabdocidaris libyca, Gregoiu , and Linlhla cavernosa, de Loriol). 
Hume, W. F., Secular Oscillaliou in Egypt during the Cretaceous and Eocene Periods. Q.J. G.S., 
vol. XVII , 1911, p. 126-127. 
20 
