Mineral Resources
The mining industry has not yet penetrated into the Cameroons, and the mineral deposits of the country are commercially improved. Cretaceous and Tertiary rocks occur in the coastal area and extend northward to the Nigerian border. Gneisses and schists of pre-Cambrian age, with intrusive granites, extend over wide areas in the hinterland, and volcanic rocks of supposed Tertiary age are very abundant. Pegmatites and quartz veins are associated with granite intrusions in the pre-Cambrian rocks. These carry tourmaline in the region north of Duala, as in the Dschang district. Quartz veins with small amounts of pyrite and arsenopyrite also occur.
Tinstone, which occurs in pegmatite veins in Nigeria, may be expected to be encountered in the Cameroons, but although prospecting has been carried on in various parts of the region bordering on Nigeria, in the hope of finding tinstone and wolframite, no results have been obtained. The only trace of gold yet discovered was an occurrence of spangles of gold of theoretical interest only, which was found in a dyke rock (a bostoorite) on the eastern boundary of the Ossidinge district.
Promising finds of mica have been made in the pegmatites of the Ossidinge and Kentu districts, and galena also occurs in the cretaceous sandstone in the Ossidinge district; but hitherto no argentiferous lead-zinc ores comparable with those of Nigeria have been located.
Iron ores, some of which are manganiferous, are abundant in the country. Many of these are of the lateritic type, and furnish material for native smelting, as in other parts of Western Africa. In some localities, iron ore has been formed by the decomposition of basalt. Masses of red and brown ores of this type are found on hill-slopes in the neighbourhood of Bali and Bamenda. A sample of this ore was found to contain 42·25 per cent. of metallic iron, 0·35 of manganese, 0·17 of phosphorus, and 12·26 of silica. Richer ores of the magnetic type are found among the pro-Cambrian gneisses.
Limestones are scarce and of unserviceable quality, but clays and loams, suitable for brick-making, are abundant. Indications of the presence of petroleum in the neighbourhood of Duala were falsified by borings. Asphal is said to occur at Ossidinge and Mamfe on the Cross River. A thin layer of coal yielding 48·3 per cent. of ash has been located at Mamfe. Salt springs exist in the Ossidinge district, and the yield of as much as from 5 to 8 per cent. of sodium-chloride from samples of brine, is believed to indicate that salt beds may be found beneath the surface in this district.