NIGERIA, a British colony and protectorate in West Africa, occupying the basin of the lower Niger and adjacent regions. Area 338,593 sq.m., pop. (1931 census) 19,130,859. Administra tively attached to Nigeria is that part of the Cameroons under British mandate, which has an area of some 34,081 sq.m. and a population of about 797,000. Nigeria is bounded south by the Gulf of Guinea ; west by Dahomey, north by the French Niger Colony; and east by the French sphere of the Cameroons. It includes the former British colony and protectorate of Lagos (q.v.), and is nearly seven times the size of England. The follow ing particulars do not include the British sphere of the Cam eroons (q.v.).
The delta region is swampy, and forms, for a distance of from 20 to 6o m. inland, a network of interlacing creeks and broad sluggish channels fringed with monotonous mangrove forests. Be yond the delta firm ground takes the place of mud and the man groves disappear. The land rises gradually at first, becoming, however, in many districts very hilly, with heights of 3,000 ft., and is covered with dense evergreen or rain forests which give place to deciduous forest as the rainfall decreases. The evergreen and deciduous forests form part of the great West African forest belt; the trees are straight, tall and cylindrical and there is little under growth, though often bound together by creepers. The forest belt
extends 5o to ioo m. and is succeeded by park-like land, the savannah and orchard forests much more extensive than the dense forest, with strips of deciduous forest going through it along the river banks.
North of the Niger-Benue confluence, which is but 25o ft. above sea-level, are hills forming the walls of the plateau which extends over the major part of the country and is part of the great plateau of North Africa. This plateau, broken only by the valleys of the rivers, does not attain an elevation approaching that of the pla teaux of South Africa, the culminating point (apart from par ticular mountain districts), situated in about o° N., reaching a height of 3,00o ft. only. The valleys of the Niger and Benue, especially the latter, are much lower, the town of Yola on the Benue, some 400 m. inland, lying at an altitude of little over 600 feet. The surface is generally undulating, with isolated "table mountains" of granite and sandstone often rising abruptly from the plain. It is clothed largely with thin forest, but becomes more open to the north until, towards the French frontier, the arid steppes bordering the Sahara are reached. Much of the country north of Zaria ( ° N.) is covered with heavy, loose sand. The most mountainous districts are northern Bauchi (a little N. of where there are heights rather above 4,000 ft.; parts of Muri, along the north bank of the Benue; and the southern border of the Benue basin, where the hills consist of ironstone, quartz and granite. On the east the plateau sinks to the plains of Bornu (q.v.), which extend to Lake Chad. Tributaries of the Niger traverse the western portion of the country, the most noteworthy being the Gublin Kebbi, or Sokoto, river and the Kaduna, which flows through a valley not more than 5oo ft. above the sea. The north eastern part of the country drains to Lake Chad by the Waube or Yo, an intermittent stream, which in its lower course forms the Anglo-French boundary. The western portions of Lake Chad (q.v.) belong to the protectorate, which contains no other large lake. The water parting between the Chad and Niger systems runs north-west and south-east from about Katsina in 13° N. to the Bauchi hills.