Description. 89 micaceous schist and greenstone. The red granite of Geological, Segadi is of the finest quality, and superior to that of Syene (v. p. 95). Jebel Moia, the largest of these hills, has a length of some miles, and rises ta height of about 1,200 feet above the plain.

Baboons are the only inhabitants of the bare rocks ; apes, parrots, and Guinea fowl inhabit the woods at their feet.

The ebony tree grows round Jebel Moia j the sycamore round Segadi. The plain of Sennar, for some distance above Khartum, exhibits only a sandy soil, mixed with river deposits. But, from Mesalrtmieh up, its character changes entirely, and the level flat, now higher above the river level, becomes a deep bed of argillaceous marl, containing calcareous concretions in great quantity. Over its surface are scattered boulders of granite, and fragments of greenstone in great numbers ; of the latter are made the mills of the country, of which every household has one.

The plain is covered with a black mould, the result of decomposition.

The argillaceous soil is retentive of water, and wheia refreshed by rain (for these rich plains are nowhere reached by the waters of the Nile), becomes exceedingly fertile. But in the dry season it has an aspect of the •most dismal sterility ; no tree, little herbage, and the naked ground cracked and gaping in all directions with the burning heat.

The belts of thick wood which extend along the banks of the Nile below the junction of its two great arms, continue along the Blue River above the junction. The foliage of all trees in this region, with the exception of the Acacia senegalensis, is scanty, and gives little shade. With the species just named are also associated the Acacia seyal and Acacia nilotica, or Sunt, producing gum arabic, Balamites Egyptians, Bhamus spina Christi, and Sodada decidua ; the last leafless, and presenting only a bunch of slender boughs. The fruit of the tamarind, called Ardeb in Nubia, is in great request for its medicinal qualities. Above Khartum the palms increase in number; the . dom and date palm are seen towards Sennar ; but more