Their appearance betrays the effects of great waves which have at one time swept over them, pouring their waters into their recesses, cleansing by force every cranny and flaw of their vegetable mould, and washing out of them every particle of soil, until, one day, by some sudden convulsion of nature, the lake subsided, leaving, a hundred feet above its surface, these grey and naked masses of granite. Any one who has seen on a rock-bound coast the war of sea-wave against granite, basalt, and sandstone, will at once recognize the effects visible at Mpimbwé. There lie piled up rocks, hundreds of tons in weight, some of them appearing to rest in such precarious positions that it seems as if the finger of an infant would suffice to push them into the deep blue lake. These, however, are not scored and grooved as are those exposed to the eroding influences of ceaseless ocean waves; they are cleanly fractured, with their external angles only exhibiting a rough polish or roundness which I take to be clear signs that at some remote time they were exposed to waves of great power. Besides, the condition of the rocks at the water-line confirms this theory. Still, it is strange that the lake should have been rising steadily ever since living men can remember, and that those rocks of Mpimbwé should bear witness to the lake’s subsidence. _June 25._—On the 25th of June, after coasting the western side of this extraordinary range and proceeding south some fifteen or sixteen miles, we arrived at Mkerengi Island, in the bay of Kirando; the large island of Makokomo lying to west of us a mile off. The natives of these parts are very amiable, though extremely superstitious. At the north-west end of Makokomo there is another lately submerged island. Close to the south-west end is a group of inhabited islands, Kankamba and Funeh being the largest and most fertile. Kirando is situated among other large villages in what appears to be a plain, hemmed in on the east by the continuation of the mountain ridges which we lost sight of when we left Karema Bay. The truncated cone of Chakavola terminates the ridge of Mpimbwé, and lies north-east from Mkerengi. Continuing our voyage southerly along the coast between the isles of Kankamba and its brothers and the shore of the mainland, and passing a couple of creeks running deep inshore, we came to Cape Muntuwa. From this cape to Msamba Island, where we encamped, the lake is edged by one successive series of gigantic blocks and crags of granite. Rock rises above rock, and fragment above fragment. Here towers a colossal mass the size of a two-storied house, bearing upon it a similar mass perhaps entire, but more probably split with a singularly clean and fresh fracture, and there springs up from the surrounding chaos a columnar block like a closed hand with outstretched fore-finger—but everywhere there is the same huge disarray, ruin, and confusion.