The discovery of diamonds at Kimberley, South Africa, has proved to be a matter, not only of commercial, but of much geological interest. The conditions under which diamonds here occur are unlike those of any other known locality, and are worthy of special attention. The first diamond foundinSouth Africa wasin1867, when a large diamond was picked out of a lot of rolled pebbles gathered in the Orange river. This led to the “river diggings” on the Orange and Vaal rivers, which continue to. the present time.