NUBIA AND THE NILE RAPIDS. 367 



steel-finches and blood-finches, have established themselves; in the 

 gardens round the houses the cape-pigeons have settled; on the 

 sand -banks in the stream have been hollowed out the shallow 

 mud-nests of the shear- waters or skimmers night-terns, of peculiar 

 habit, who do not begin to seek their prey until the twilight, and 

 fish, not by diving, but by skimming over the waves and rapidly 

 ploughing the water with their bills, thus catching small creatures 

 which swim on or near the surface. 



But this cheerful region has narrow limits. Below the ruined 

 temple of Barkal the desolate and barren hills again encroach on 

 the river, excluding fertile land and steppe alike. The last group 

 of rapids now lies before the traveller who is making his way 

 up-stream. The region of the third group of cataracts is not so 

 unutterably poor as the rocky valley. Well-tilled, though narrow, 

 strips of land lie on either bank, and there are fertile islands in 

 mid-stream; thus there is not that look of hopeless poverty which 

 is characteristic of the region already traversed. The masses of rock 

 on the banks are more broken up than those in the rocky valley, and 

 there are many of the so-called " stone-seas ", hillocks and walls of 

 wildly jumbled blocks and rolled stones, such as mighty streams 

 leave behind when they dig their bed deeper in the valley. On each 

 side, usually on the top of the cliff next the stream, there are great 

 blocks of more than a hundred cubic yards in bulk, which rest so 

 loosely on their substratum that they oscillate in violent wind, and 

 could be hurled down by a few men with levers. In many places 

 these stone-seas present a most extraordinary appearance. It seems 

 just as if giants had for a whim amused themselves by erecting 

 cones and pyramids, mounds and ramparts to form a weirdly-dis- 

 ordered parapet on the river's rocky embankment. But it is not so 

 much to this strange natural architecture as to ancient works of 

 man's own hand, that the third group of rapids owes its charac- 

 teristic appearance. On all suitable rock-projections, and especially 

 on the larger islands, rise buildings with inclosing walls, towers, 

 and jagged battlements, such as are not seen elsewhere in the Nile 

 valley. These are fortifications of ancient days, castles of the river- 

 chiefs, erected for protection and defiance, to secure life and property 



