Apart from this local development of igneous rocks at the north end of Lake Nyassa, the only other break in the granitic series throughout the area traversed by my line of march occurs near the native village of Karonga, on Lake Nyassa. About a dozen miles from the north-western lake shore on the route to Tanganyika, after following the Rukuru river through a defile of granite rocks, I came, to my great surprise, upon a well-marked series of stratified beds. At a bend in the river a fine section is exposed. They lie throw against the granitic rocks, which here show signs of disturbance, and consist of thin beds of very fine light-gray sandstone, and blue and gray shales, with an occasional band of gray limestone. By camping at the spot for some days, and working patiently, I was rewarded with the discovery of fossils. This is, of course, the main interest of these beds,--for these are, I believe, the only fossils that have ever been found in Central Africa. The shale, naturally, yielded the most productive results, one layer especially being one mass of small _Lamellibranchiata_. Though so numerous, these fossils are confined to a single species of the _Tellinidæ_, a family abundantly represented in tropical seas at the present time, and dating back as far as the Oolite. Vegetable remains are feebly represented by a few reeds and grasses. Fish-scales abound; but I was only able, and that after much labor, to unearth two two or three imperfect specimens of the fishes themselves. These have been put into the accomplished hands of Dr. Traquair of Edinburgh, who has been kind enough to furnish the following account of them:-- EDINBURGH, 23d April, 1888. DEAR PROFESSOR DRUMMOND--I have carefully examined the six specimens of fossil fish-remains from Central Africa, which you submitted to me, and though I certainly would have wished them to have been less fragmentary, I shall do my best to give an opinion upon them. No. 1, the largest, is the hinder portion of a fish of moderate size, showing not only scales, but also the remains of the dorsal, anal, and caudal fins. The caudal is strongly heterocercal, and was probably deeply bifurcated, but the rays of the lower lobe are very badly preserved: only the posterior parts of the dorsal and anal are seen, nearly opposite each other, and composed of fine, closely placed, and closely articulated rays. The scales, displaced and jumbled up, are osseous, thick, and rhomboidal, with a strong blunt carina on the attached surface, while the exposed part of the external surface is covered with ganoine, and ornamented with rather sparsely scattered pits and punctures.