9/27 'Though there is still a great deal of uncertainty about the way in which laterite was formed, the facts which are known of its distribution seem to show that it is a distinct form of weathering, which is confined to low latitudes and humid climates; its formation seems to have been a slow process, only possible on flat or nearly flat surfaces, where surface rain-wash could not act' (Oldham, in _The Oxford Survey of the British Empire_, vol.ii, Asia, p. It hardens and darkens by exposure to air, and is occasionally used as a building stone. |