The region traversed from the eastern slopes of that broad range which we began to skirt soon after passing to the left bank of the Wami river, as far as Chunyu (a few miles west of Mpwapwa), comprises the extreme breadth of the tract distinguished in the work, ‘How I found Livingstone,’ as the Usagara mountains. The rocks are of the older class, gneiss and schists, but in several localities granite protrudes, besides humpy dykes of trap. From the brackish stream east of Tubugwé, as far as Mpwapwa, there are also several dykes of a feldspathic rock, notably one that overlooks the basin of Tubugwé. The various clear streams coursing towards the Mukondokwa, as we dipped and rose over the highest points of the mountains among which the path led us, reveal beds of granite, shale, and rich porphyritic brown rock, while many loose boulders of a granitic character lie strewn on each side, either standing up half covered with clambering plants in precarious positions upon a denuded base, or lying bare in the beds of the stream, exposed to the action of the running water. Pebbles also, lodged on small shelves of rock in the streams, borne thither by their force during rainy seasons, attest the nature of the formations higher up their course. Among these, we saw varieties of quartz, porphyry, green-stone, dark grey shale, granite, hematite, and purple jasper, chalcedony, and other gravels. The rock-salt discovered has a large mass exposed to the action of the stream. In its neighbourhood is a greyish tufa, also exposed, with a brown mossy parasite running in threads over its face. Wood is abundant in large clumps soon after passing Kikoka, and this feature of the landscape obtains as far as Congorido. The Wami has a narrow fringe of palms on either bank; while thinly scattered in the plains and less fertile parts, a low scrubby brushwood, of the acacia species, is also seen, but nowhere dense. Along the base and slopes of the mountains, and in its deep valleys, large trees are very numerous, massing, at times, even into forests. The extreme summits, however, are clothed with only grass and small herbage. Mpwapwa has also some fine trees, but no forest; the largest being the tamarind, sycamore, cottonwood, and baobab. The collection of villages denominated by this title lies widely scattered on either side of the Mpwapwa stream, at the base of the southern slope of a range of mountains that extends in a sinuous line from Chunyu to Ugombo. I call it a range because it appeared to be one from Mpwapwa; but in reality it is simply the northern flank of a deep indentation in the great mountain chain that extends from Abyssinia, or even Suez, down to the Cape of Good Hope. At the extreme eastern point of this indentation from the western side lies Lake Ugombo, just twenty-four miles from Mpwapwa.