Geological Interpretations of Geodetic Results: A Critical Examination of Mr. R. D. Oldham's Recent Treatise on Himalayan Structure

Abstract

subject of first-rate importance. It has come out very markedly in help he has more recently given me for the 1/5 M map of Asia, a much more difficult ques? tion. I should like to emphasize my appreciation of the very great services Mr. Young has rendered. Mr. McCaw's question, whether volcanic change could have affected the source of the Kagera, I am unable to answer. I am not sure whether any competent geologist has been to the source of the Kagera ; it is rather east of the parts affected by the great volcanic outburst in the western rift. However, if it is true that Lake Kivu used to be in the Nile system, then clearly the volcanic outburst has affected the source of the Nile very materially, although not at the particular point Mr. McCaw mentioned. In closing, I should like to express my thanks to those who have spoken all too appreciatively of the work we have been trying to do here, and also to call attention to the fact that we are for the first time making a serious attempt to produce a layer-coloured map of Africa upon an adequate scale. We cannot expect to get contours at close intervals because the parts sufficiently well surveyed are very slight; but we have tried to make contours at intervals of 500 metres, and when they are layer-coloured you do get a representation that is beginning to be satisfactory of what is, I think, the most interesting country in the whole world, the lake region and the two rift valleys of Central Africa.