Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. N 1807 a Survey detachment was deputed by the Surveyor General of Bengal to explore the source of the Ganges: this was the first expedition to the Himalaya undertaken for purely geographical purposes. A hundred years have now elapsed, during which geographical and geological information has been steadily accumulating and we have at length reached a stage where there is danger of losing our way in a maze of unclassified detail it is therefore desirable to review our present position, to cc-ordinate our varied observations and to see how far we have progressed and what directions appear favourable for future lines of advance.