hippopotamus, Irish elk, cave-bear, hyæna, etc., could not have done so had the English Channel been then in existence. Moreover, the bones of several of these animals have been repeatedly dredged up in fishermen's nets from the bed of the North Sea, under conditions which show that they found the means of living in the submerged localities in which their osseous remains are now found. Not less convincing is the fact that flint implements of Palæolithic types have been dug up from the valley gravels of the Thames and the Somme, considerably lower than the present surfaces of these estuaries. The discovery of the bones of the woolly-haired rhinoceros, reindeer, horse, etc., in a recently explored cave in Jersey can only be explained on the supposition that the island had been formerly part of the French mainland. The same argument applies to the finding of skeletons of the great Irish elk in the Isle of Man. Also, the submerged forests and raised beaches, described in geological text-books as occurring in several places around our seashores, testify to the prevalence of land oscillations within comparatively recent times.
Animals.—Concurrent with these fluctuations in the formation and distribution of continental land-areas the organic world was pursuing its marvellous course on the lines of evolution, producing, with unstinted copiousness and ever-changing adaptations, multitudes of living organisms, strange and sometimes fantastic-looking objects, whose sole
