_19th April._—After we had navigated the whole night, we found ourselves this morning in the country called Tura, from whence various roads lead to Kordofàn. The flat shores are sandy, and rise, having a bad and meagre growth of trees. On the right and left are some hills of downs, on which we find reddish pieces of granite, such as I met with near the Sagiën. Whence this poverty of humus, for Nature ought to be more fertilizing, as she washes away sand from the ground first, and then brings the lighter humus just as we see at the Delta? We saw nothing of the mountain group of Araskòll, for the vessels go now too low. Suliman Kashef continues his voyage, whilst Selim Capitan and Arnaud have landed on the left shore, the latter to seek for gold in the Araskòll. The shores continue in sandy downs, especially on the right side, but an immeasurable level plain extends on the left, of which we have an extensive view, by reason of the shores being scarcely elevated above the water. This character of the country passes also subsequently to the right side. The entirely flat margin of the broader part of the stream, which we sail through with a favourable east wind, following Suliman Kashef, is not pure sand; yet we observe upon it thin tracts of underwood standing back a little, and dwarf mimosas. This part is, as it were, the mouth of the river, and formed, in ancient times, a shallow lake by the conflux of the White and Blue streams, as the downs on the right prove, which are in connection with those at Khartùm, and formed the very same embankment; for the more violent pressure of the Blue river clearly opposes the broad stream of the White one, as we see plainly near the island of Tuti, and perhaps only subsequently broke through the angle of land at the right side of this island; if it made previously, as the Arabs believe, a bend from the city of Soba to the west into the White river, and thus surrounded, with the latter, the desert rocks of Omdurman lying at the side. An investigation, however, would be necessary to ascertain this point. The Downs continue again afterwards at the right shore, alternating even with downs of earth. If a shallow lake of such dimensions existed here at one time, the north wind drove its waves and billows to this side, and piled up these irregular heights, which are not arranged in a row like a chain, but sometimes advance, sometimes retreat. The lake withdrew, and the river levelled, took and gave, so that in many places long tracts of continuous sandy shores existed, having, however, a fertile substratum, because otherwise there could not be the vegetation that there is. This subjacent soil is also frequently visible as humus or morass, and under it an adhesive blue clay is found, as I ascertain plainly by the sailors’ poles, which are continually being pushed into the deep. Thermometer 22° 29° to 30° 28°.