One of the drawbacks of working in a distant land is that the valuable help of the friendly critic is rarely available, and that, therefore, however strongly the truth of conclusions arrived at may be felt by oneself, it is impossible to expect readers in England to accept without reserve statements that may with perfect justice be said to require corroboration by other observers. I have felt the force of this consideration particularly in the case of the clays of the Malayan Gondwana rocks, which I have described in more than one publication; and as the conclusions in those descriptions are so far removed from what was to be expected in a country where recent alluvium was until quite lately believed to be the most important formation, it is, I think, advisable to place on record in some detail any corroborative evidence that may be brought to light. An additional reason for this course is the constant change in the mine-sections owing to mining operations, and also to the rapidity with which sections weather.