Roughly we may describe the Basin of the Congo as extending from the 5th degree of North, to the 12th degree of South, latitude, and from the hills skirting the coast of the Atlantic Ocean to 31st or 32nd degree of East longitude.
Along what is known as the South-West Coast of Africa, from the Gulf of Biafra southwards, stretches a ridge of hill country. It commences about fifty to seventy miles inland, and is about 300 miles in width. In some parts it attains an elevation of 5,000 or more feet, but the general altitude near the Congo is from 2,000 to 2,500 above the level of the sea. It is really a belt or elevated plateau; rich soil is to be found on the summits of the ‘hills,’ but the whole has been torn and worn by the rains; little streams have in time cut out deep gorges, the sides of which are being further eroded, until what was once a rolling table-land appears as a chaos of hills; only from a few heights can one gain a fair idea of the nature of the country.
This plateau belt forms the western watershed of the Congo River, and on its seaward slopes gives rise to many unimportant streams, of which the Cameroons, Gaboon, Ogowai, Kwilu, Chiloango, Mbidiji, (Ambrize), Loje, and Kwanza are the principal. The Ogowai is the most important, and has been explored by M. de Brazza for the French Government, which has now annexed its entire basin. It is navigable for some 150 miles for vessels of light draught; but beyond its course is much impeded by cataracts.
This water-torn plateau country, with its little useless rivers, has presented a formidable obstacle to exploration, and has served to throw