The country on the whole is mountainous and forms the north-west limit of the central African plateau. The coastland is flat alluvial country spreading out on either side of the Cameroon Mountains, and broken up with mangrove swamps, lagoons and deep estuaries. The Rio del Rey region on the west of the Cameroon Mountains is a stretch of alluvial land with a breadth of thirty to forty kilometres, which forms the extreme eastern portion of the great alluvial plain extending from the Gold Coast to the Cameroon, and attaining its greatest development in the Niger Delta. Within the alluvial the volcanic massive of the Cameroon Mountain rises to a height of 4,070 m., and divides the land into two parts, which are connected only by a small and high strip of territory. To the east of the dividing mountain lies Dualaland. The other three orographical regions which comprise the Cameroon country includes the Cameroon plateau, which forms the largest and most important part of the colony; the enormous region of Adamana, which is generally level and nowhere reaches an elevation of more than 600 metres; and the extensive swampy lands of the Lake Chad basin which are under water during several months of the year. The greater part of the colony is covered with red, loamy, sandy weatherings, which are characteristic of the tropics. If this red earth contains hard concretions of brown iron ore, they are named “Laterit.” These cellular-like volcanic scoria are characteristic of the surface of the soil generally, and especially in those districts where the loamy deposits have been washed away by heavy rains. Vegetable soil is more abundant in the rainy regions of the south, and also in the lowlands. Indeed the result of this humid weathering is a kind of whitish yellowy kaolin, or china clay, which is found in the south plateau. A blackish mould to a thickness of one or two feet covers the lowland south of Lake Chad, and is there called “Firki.” Whilst in the south of the colony red and yellow clayey soil preponderates, the further north one goes to the dryer regions, reddish sand, a product of the physical weathering, is to be found. CLIMATE.