_Geology._--The whole formation is Archean and Primary (with a few modern plutonic outbursts), and chiefly consists of granite, felspar, quartz, gneiss, schists, amphibolite and other Archean rocks, with Primary sandstones and limestones in the basin of Lake Nyasa (a great rift depression), the river Shiré, and the regions within the northern watershed of the Zambezi river. Sandstones of Karroo age occur in the basin of the Luangwa (N.E. Rhodesia). There are evidences of recent volcanic activity on the summit of the small Mlanje plateau (S.E. corner of the protectorate: here there are two extinct craters with a basaltic outflow), and at the north end of Lake Nyasa and the eastern edge of the Tanganyika plateau. Here there are many craters and much basalt, or even lava; also hot springs. Entry: BRITISH