If we now turn further east to Belgium and its borders, we shall find the same conclusion arrived at by inquirers. In the admirable memoir of M. d'Acy, already named, entitled “Limon des Plateaux du Nord de la France,” the author has examined in great detail and with care the composition of the loamy mantle that overspreads the other surface deposits of Belgium and Picardy. His sections and descriptions show very clearly how its texture, passing from coarse materials in its bottom layers and gradually getting finer and more pulverulent in its upper ones, is such as we should expect from the effect of gravitation acting upon great masses of mud, etc., borne along by a rapid flood.