In view of the probability that there is likely to be some little delay in publishing the official Memoir on the Bufumbira volcanic rocks, which is in course of preparation by Mr. A. D. Combe and the writer, with, we hope, collaboration with authorities in England, permission has been given to publish a short summary of the results so far obtained in the investigation of these rocks. Mr. Combe has made a careful geological survey of the ground and has separated on his map forty-nine flows from nearly forty different centres situated at the south-west corner of the Uganda Protectorate. The remainder of this large volcanic field lies in the Belgian Congo to the west and south, and though all of those volcanoes, several of which are still active, have been visited by geologists and specimens of the rocks obtained, no very detailed field-work has been published on them, either by us or any other observers up to the present time; so far as is known to the writer.