552 THE FRESH- WATER LOCHS OF SCOTLAND 
Bahr el-Ghazal, is also given to a broad current which flows from 
the mouth of the Shari River to the eastern extremity of the lake, 
following the shore to the north-west side of the lake, where it 
gradually loses itself. 
Lieutenant Boyd Alexander^ explored Lake Chad in 1904, and 
found progress across it by boat to be extremely difficult, owing to 
the o-reat belts of hio;h reeds and the shallowness of the water. He 
describes the lake as being practically divided into two basins by 
about 25 miles of marsh and thick bush. The northern basin, 
which receives the waters of the River Yo, is the shallower, ap- 
parently not exceeding 4 feet in depth. The southern basin, into 
which the Shari flows, has a depth of about 12 feet in places, and the 
islands in it, which form a prominent feature, are fertile and thickly 
populated. The lake, which is generally shallow and swampy, opens 
out into a flne sheet of water round the mouth of the Shari. 
The Aujila Depression is a remarkable zone of oases or depres- 
sions extending from the Wady Fareg, near the south-east angle of 
the Gulf of Sidra on the coast of Tripolis, eastwards to the Bahriyeh 
(Lesser) Oasis in Middle Egypt. This depression assumes somewhat 
the aspe(;t of a long, winding, dry water-course, expanding at intervals 
into patches of perennial verdure and shallow saline basins, and was 
thought by some to have been of marine origin. Hence Rohlfs con- 
ceived the idea of again transforming this chain of oases into an 
inland gulf by admitting the Mediterranean waters through a cutting 
to the Wady Fareg and opening a waterway into the Libyan Desert. 
This project, analogous to Roudaire's scheme in respect of the 
Algerian Sahara, was subsequently abandoned when it was discovered 
that only one of the oases, Swah, with its eastern extension, was below 
sea-level. 
Kufara Oases. — South of the Aujila depression in the heart of 
the Libyan Desert Ave oases, called the Kufara Oases, stretch for a 
distance of 200 miles north-west and south-east, with a total area of 
7000 square miles. Although there are no surface streams, fresh 
water in abundance is easily obtained by tapping the underground 
water occurring at depths of from 3 to 10 feet on the margins of 
saline ponds and marshes. 
Birket Qarun is a brackish lake in the lowest part of the 
F'ayum province of Egypt, a large circular depression in the Libyan 
Desert separated from the Nile valley by a strip of desert two to 
seven miles in width. A narrow watercourse, over 200 miles long, 
the Bahr Yusef, enters the lake through a gap in the Libyan Hills, 
connecting it with the Nile and forming a narrow neck of cultivation 
across the desert. The Birket Qarun is usually regarded as a remnant 
^ See Geogr. Jour/i., vol. xxx, p. 119, 1907. 
