220 NOETH-EAST AFEICA. and certiiin species of fish, notably the siluroid sinodoiifus, lie torpid till reanimated by the returning waters of the rainy season. The water-parting between the Nile basin and the slope of the Red Sea consists of irregular cliffs of various heights, but none lower than 3,300 feet. Primitive rocks and volcanic formations alternate in this mountainous region, which in many places presents the appearance of a plateau scored with ravines. At the mouth of the valleys sloping from the Abyssinian uplands, notably on the northern declivity of the Nakfa Mountains, are seen piles of debris, which Heuglin felt inclined to regard as the moraines of ancient glaciers, similar to those found by Fraas in the peninsula of Sinai. The granite rocks on both sides of the Red Sea, their slopes completely barren of vegetation and glittering with the many colours of their crj'stalline strata, resemble each other by their bold outlines and brilliant colours. One of the finest on the western side is the isolated Mount Shaba, rising above the marshy depression in which the waters of the Barka run dry. The vast peninsula of alluvial lands which at this point projects into the Red Sea basin shows that the river was formerly much more abundant than it is now. Climate, Flora, Fauna. The climate of Upper Nubia occupies a middle position between the humid zone of the equatorial lands and that of the slight rainfall where the Nubian desert begins. Still there is no part of the country which does not possess a rainy season, more or less abundant. At Khartum, situated about the middle of Upper Nubia, the kharif occasionally commences in May, more frequently in June or July, terminating in September. Rain is brought down by the easterly or south-easterly winds — that is to say, the southern trade winds of the Indian Ocean ; but after the rains the dry north winds return, lasting till March, the period of the equinox. During this season the temperature occasionally falls to 50° F., and at this time of the year the mornings and evenings are so cold as to require warm clothing ; the daily oscillations of temperature average 60° F. During the kharif it is dangerous to remain on the frequently flooded river banks on account of the prevalent marsh fevers, and numerous tribes then withdraw to the upland regions of the interior. The black and the white ibis, very common in the valley of the Blue Nile during the season, also disappear before the rains, " for fear of the malaria," as the natives say. Upper Nubia is naturally divided into an agricultural and a grazing country, according to the abundance of the rains and running waters, the nature and eleva- tion of the land. In the Fazogl country and on the banks of the Upper Jabus the arborescent vegetation is almost as leafy as in the verdant valleys surrounding the great lakes. Beyond the forest zone, which encircles the Abyssinian plateaux throughout most of their extent and which is continued along the rivor banks, the mouths of the valleys and the hills are pre-eminently adapted for agriculture. Thanks to their fertile alluvia and splendid climate, these lands may one day become one of the richest cotton and tobacco producing countries in the world. The steppe,
