Writing from the Station Hospital at Ladysmith, Dr. Henry Exton, F.G.S., has communicated his observations on the geology of the country near Ladysmith, in the northern part of Natal, in letters to Professor T. Rupert Jones. A very noticeable geological feature is the prevalence of an igneous rock (intrusive andesitic diabase) on all the hills from Umbulwana, four miles east by south from Ladysmith, to the famed Spion Kop, sixteen miles west from here.