Mr. Sydney Ryan, of Darkton, Managing Director of the Ryan Tin Mines, situated on the Embabaan River in West Swaziland, has collected and sent to England a large collection of rock-specimens from the Ingwenya Berg, the dominating feature of the district. He has also provided plans and sections of the district, which are here partly reproduced. The specimens have been presented to the Mineralogical Department of the British Museum, together with a complete catalogue, having reference to the Sections referred to above, and indications of the lithological characters of the 140 specimens. Mr. G. Th. Prior, F.G.S., has kindly aided the writer in the critical examination of the rocks, and is communicating a description of those of economic value to the forthcoming number of the Mineralogical Magazine.