— 107 — 
CHAPTER V. 
The Oases and the Geology of the Nile valley , 
by Mr. H. J. L. Beadnell, F. G. S. f F. R. G. S. 
40. The Oases.— The chief oases (*) of the Libyan desert — Dakhla, Kharga, 
Baharia and Farafra, — occupy extensive depressions cut down through the 
horizontal Eocene strata ( 2 ) to the underlying saddle of Cretaceous rocks ; some 
of the more porous beds of the latter are water-bearing and from them, either 
through natural passages or through artificial borings, the water rises to the 
surface, often under considerable pressure. The floor level varies considerably 
but the cultivated lands in general lie between 70 and 115 metres above 
sea level. 
41. Dakhla oasis. — This, by far the most important and prosperous of the 
Egyptian oases, lies three days’ march west of Kharga, or about 300 kilometres 
due west of Armant in the Nile valley. The site is a depression lying at the 
foot of the great east and west Cretaceous escarpment, bounded to the south by 
the undulating desert of Nubian sandstone, which stretches unchanged almost 
to the heart of the continent. The inhabitants of Dakhla, numbering over 
17,000, are distributed among 12 villages and form a practically self-supporting 
community. The cultivable land within the oasis (400 square kilometres) 
amounts to nearly 50,000 acres, of^ which one half is under cultivation; in addition 
several extensive areas of alluvium covered ground exist outside the oasis proper, 
notably on the Gabbari road between Dakhla and Kharga. Owing to the diffi- 
culty of drainage, salines, saltyland, marshes and pools occupy some 7,000 acres. 
There are nearly 130,000 adult palm trees in Dakhla, a large export trade in 
dates being carried on with the Nile valley ; the finest crops of wheat and barley 
are raised, while the fruits of the oasis, oranges, apricots, mulberries, etc., are 
abundant and of excellent quality. 
Taxes are levied as follows : — (1) Mature date-palms are taxed 1^ piastres 
each per annum ; (2) Modern wells (i.e. biyar, made with the existing boring 
plant) pay 50 piastres per annum per qirat of water ; (3) Ancient wells (aiyun) 
pay the same, except that in some cases those used for irrigating palmgroves 
are exempt. There are 7^ trees and 1), acres per inhabitant, and the total tax 
paid by the community is about £E. 2,500. 
The water-supply of the oasis is derived from an underground bed of sand- 
stone, 55 metres thick, underlying a dense impervious red clay 45 metres in 
C 1 ) See Geological Survey reports, P.W.M., Cairo. 
( 2 ) With the exception that Dakhla is almost entirely cut out in Cretaceous strata. 
