6 SOUTH AND EAST AFRICA. The limestone cliffs are in many places pierced by deep caverns, where arc found narrow and hitherto unfathomed wells, which have given rise to numerous native legends. Thermal springs occur at various points of the territory ; but no volcanic rocks have been found, except in the northern districts, and even here the eruptive forces appear to have been limited to a few outbursts of basaltic lavas. Ladislas Magyar speaks of a volcano, but without stating whether he visited it himself, and there is every reason to believe that he was deceived by false reports, possibly even by the romantic but untrustworthy descriptions of the traveller J. B. Douville.* This active volcano, known as the Mulondo-Zambi, or " Demon Mountain," was reported to lie in the Libollo country some 30 miles to the south of the Cuanza. From the highest crater, overlooking all the surrounding crests, flames and smoke emitting a strong sulphurous odour were said to be ejected at intervals of three or four hours. The natives never venture to approach this burning mountain, which thoy suppose to be inhabited by the spirits of their ancestors. But all these reported eruptions will probably sooner or later be explained by some meteorological phenomena, like those of the pretended Otumbi volcano in the Gaboon territory. River Basins. Limited eastwards by the course of the Kwango, the Angola region is traversed by numerous streams, which either flow through deep gorges across one or more of the outer terraces of the plateau, or else, like the Cuanza and the Cunene, force their way seawards through the whole breadth of the intervening uplands. In the northern section of the territory, where the annual rainfall is relatively heavier than in the south, every valley has its perennial stream, although these rivers are prevented by the disposition of the rugged surface from uniting in one large fluvial system. A considerable number of the streams however flow, not directly seawards, but either to the east in the direction of the Kwango, or north- wards through the Kwilu, Lu-fu and Mposo to the Congo. Those which, like the Lelunda, Mbrish, and Loje, reach the Atlantic directly, are disposed in parallel valleys in the direction from east to west. But their mouths are nearly all closed to shipping b}' impassable burs, so that they are accessible only to small flat- bottomed craft. The Mbrish, which escapes from the Zonibo highlands to the east of San- Salvador, develops a series of cascades, the first of which has a fall of 150 feet, and the whole chain of rapids a total incline of 430 feet. The Dandd and Bengo, however, being navigable above their bars, present certain advantages as highways of commerce in the interior, and their shady banks are lined with plantations. But the chief river in Angola, and one of the most copious of the secondary watercourses in the whole of Africa, is the Cuanza, whose valley forms the Atlantic section of the transxerso depression which is continued through the Zambese basin south-eastwards to the Indian Ocean, The chief headstreams of the Cuanza have • " Voyage au Congt) et dans rintcrieur de I'Afrique equinoxiale."
