270

COMPARISON OF MUNDESLEY

CHAP. XII.

striking analogy of the Mundesley deposits, and those atHoxne thirty miles to the S.S.W., the latter so productive offlint implements of the Amiens type. Both of them, likethe Bedford gravel with flint tools and the bones of extinctmammalia (noticed at p. 215), are post-glacial. It will alsobe seen that a long series of events, accompanied by changesin physical geography, intervened between the ‘ forest bed,’No. 2, fig. 32, p. 255, when the Elephas meridionalis flou-rished, and the period of the Mundesley fluviatile beds a, b,c ; just as in France I have shown, p. 232, that the sameE. meridionalis belonged to a system of drainage differentfrom and anterior to that with which the flint implements ofthe old alluvium of the Somme and the Seine were con-nected.

Before the growth of the ancient forest, No. 2, fig. 37,the Mastodon arvernensis , a large proboscidian, character-istic of the crag, appears to have died out, or to have becomescarce, as no remains of it have yet been found in the Norfolk cliffs. There was, no doubt, time for other modifications inthe mammalian fauna between the era of the marine beds,No. 3, p. 255 (the shells of which imply permanent sub-mergence beneath the sea), and the accumulation of theuppermost of the fluvio-marine, and lignite beds, No. 4.In the interval we must suppose repeated changes of level,during which land covered with trees, an estuary with itsfreshwater shells, and the sea with its Mya truncata andother mollusca still retaining their erect position, gained byturns the ascendency. These changes were accompanied bysome denudation followed by a grand submergence of severalhundred feet, probably brought about slowly, and whenfloating ice aided in transporting erratic blocks from greatdistances. The glacial till, No. 5, then originated, and thegravel and sands, No. 6, were afterwards superimposed onthe boulder-clay, first in horizontal beds, which became sub-