ON THE “SUDD "-FORMATION OF THE UPPER NILE. 51 
Some Notes on the “ Sudd "-Formation of the Upper Nile. By 
A. F. Brow, Director of Woods and Forests in the Soudan. 
(Communieated by C. H. Wniaur, A.L.S.) 
[Read 3rd November, 1904.7 
Mvcnm has already been written about the vegetation of the 
marshes of the Upper White Nile. Sir William Garstin's 
admirable report on the Bahr el Jebel, published in 1901, not 
only describes the chief constituents of the “ Sudd,” but also the 
circumstances in which vast masses of floating vegetation are 
moved hither and thither and block the waterways, by forming 
dams (Arab “ sudd”) across them. A trip in a sailing-boat 
undertaken in 1903, which kept me for about four weeks in that 
country, and another shorter trip recently made, have enabled 
me to add the following notes, which may be of interest as 
tending to show the process of Sudd-formation. 
The mouth of the Bahr el Jebel near Lake No, and at 627 miles 
by river above Khartoum, may be taken as the northern gate of 
the Sudd-region—a vast country of swamps, which stretches 
westward across the mouths of all the tributaries of the Bahr el 
Ghazal, which, with a stretch of the White Nile joined at 
Lake No, roughly form the northern boundary. Eastward the 
swamps reach in their northern portion as far as the some- 
what higher land between the Bahr el Jebel and the arm of the 
Nile known as the Bahr el Zeraf. To the south of the spot 
where this arm leaves the Bahr el Jebel, at about 240 miles by 
river to Lake No, the swamps stretch to the east perhaps as 
faras the Upper Sobat. Southward the swamps extend to beyond 
Gondokoro, but they are of lesser width at Bor, a Dinka village 
about 380 miles by river from Lake No. 
In the Sudan, when speaking of the “Sudd,” it is generally 
understood that the portion of the river between Lake No and 
Shamba is meant. Shamba is a military post situated on the 
left bank 266 miles from Lake No. It was in this section 
that, after the overthrow of the Dervish rule, the channel was 
found to be blocked at several places by masses of floating vege- 
tation, the clearing of which has cost the Egyptian Government 
considerable sums of money, and the Sudan Government the 
health and lives of many of its employés. In this portion the 
LINN. JOURN.—BOTANY, VOL. XXXVII. F 
