We have sifted the evidence furnished by the Loess, by the loams and brick-earths, and by the valley terraces which are such sonspicuous features in the surface geology of Europe, and we have found them furnishing a perfectly consistent and perfectly reasonable story. We have still left for consideration the most eloquent for aur purpose of all the surface deposits, namely, the great sheets of angular gravel which many of us have examined with curious interest for many days, and which mantle so much of the land on either side of the English Channel.