[BE] For interglacial beds of north Germany see Helland: _Zeitschr. d. deutsch. geol._ Ges., xxxi., 879; Penck: _Ibid._, xxxi., 157; _Länderkunde von Europa_ (Das deutsche Reich), 1887, 512; Dames: _Samml. gemeinverständl. wissensch. Vorträge, von Virchow u. Holtzendorff:_ xx. Ser., 479 Heft; Schröder: _Jahrb. d. k. geol. Landensanst. f._ 1885, p. 219. For further references see Wahnschaffe, _op. cit._ I have not thought it worth while in this paper to refer to the interglacial deposits of our own islands. A general account of them will be found in my _Great Ice Age_, and _Prehistoric Europe_. The interglacial phenomena of the Continent seem to be less known here than they ought to be. [BF] _Zeitschrift d. deutsch. geolog. Gesellschaft_, Bd. xxxvii, p. 197. [BG] _Anzeichen einer interglaziären Epoche in Central-Russland_, Moskau, 1891. No mere temporary retreat and re-advance of the ice-front can account for these phenomena. The occurrence of remains of the great pachyderms at Rixdorf, near Berlin, and the character of the flora met with in the interglacial beds of north Germany and Russia are incompatible with glacial conditions in the low-grounds of northern Europe. The interglacial beds, described by Dr. C. Weber[BH] as occurring near Grünenthal, in Holstein, are among the more recent discoveries of this kind. These deposits rest upon boulder-clay, and are overlaid by another sheet of the same character, and belong, according to Weber, to "that great interglacial period which preceded the last ice-sheet of northern Europe." The section shows 8 feet of peat resting on freshwater clay, 2 feet thick, which is underlaid by some 10 feet of "coral sand," with bryozoa. The flora and fauna have a distinctly temperate facies. It is no wonder, then, that Continental geologists are generally inclined to admit that north Germany and the contiguous countries have been invaded at least twice by the ice-sheets of two separate and distinct glacial epochs. This is not all, however. While every observer acknowledges that the Diluvium is properly divided into an upper and a lower series, there are some geologists who have described the occurrence of three, and even more boulder-clays--the one clearly differentiated from the other, and traceable over wide areas. Is each of these to be considered the product of an independent ice-sheet, or do they only indicate more or less extensive oscillations of the ice-front? The boulder-clays are parted from each other by thick beds of sand and clay, in some of which fossils have occasionally been detected. It is quite possible that such stratified beds were deposited during a temporary retreat of the ice-front, which when it re-advanced covered them up with its bottom-moraine. On the other hand, the phenomena are equally explicable on the assumption that each boulder-clay represents a separate epoch of glaciation. Until the stratified beds have yielded more abundant traces of the life of