Ramsay points out indications, first of an intensely cold period, when land was much more elevated than it is now; then of submergence beneath the sea; and, lastly, re-elevation attended by glacial action. “When we speak of the vegetation and quadrupeds of Cromer Forest being pre-glacial,” says Lyell, “we merely mean that their formation preceded the era of the general submergence of the British Isles beneath the waters of the glacial sea. The successive deposits seen in direct superposition on the Norfolk coast,” adds Sir Charles, “imply at first the prevalence over a wide area of the Newer Pliocene Sea. Afterwards, the bed of the sea was converted into dry land, and underwent several oscillations of level, so as to be, first, dry land supporting a forest; then an estuary; then again land; and, finally, a sea near the mouth of a river, till the downward movement became so great as to convert the whole area into a sea of considerable depth, in which much floating ice, carrying mud, sand, and boulders melted, letting its burthen fall to the bottom. Finally, over the till with boulders stratified drift was formed; after which, but not until the total subsidence amounted to more than 400 feet, an upward movement began, which re-elevated the whole country, so that the lowest of the terrestrial formations, or the forest bed, was brought up to nearly its pristine level, in such a manner as to be exposed at a low tide. Both the descending and ascending movement seem to have been very gradual.” [Illustration: Fig. 193.--Palæophognos Gesneri. Fossil Toad.] EUROPEAN DELUGES. The Tertiary formations, in many parts of Europe, of more or less extent, are covered by an accumulation of heterogeneous deposits, filling up the valleys, and composed of very various materials, consisting mostly of fragments of the neighbouring rocks. The erosions which we remark at the bottoms of the hills, and which have greatly enlarged already existing valleys; the mounds of gravel accumulated at one point, and which is formed of rolled materials, that is to say, of fragments of rocks worn smooth and round by continual friction during a long period, in which they have been transported from one point to another--all these signs indicate that these denudations of the soil, these displacements and transport of very heavy bodies to great distances, are due to the violent and sudden action of large currents of water. An immense wave has been thrown suddenly on the surface of the earth, making great ravages in its passage, furrowing the earth and driving before it débris of all sorts in its disorderly course. Geologists give the name of _diluvium_ to a formation thus removed and scattered, which, from its heterogeneous nature, brings under our eyes, as it were, the rapid passage of an impetuous torrent--a phenomenon which is commonly designated as a _deluge_.