The line of British coast considered in the preceding chapter offered no example of the conflict of two antagonist forces ; the entrance, on the one hand, of a river draining a large continent, and on the other, the flux and reflux of the tide, aided by a strong current setting across a river's mouth. But when we pass over by the Straits of Dover to the continent, and proceed, northwards, we find an admirable illustration of such a contest, where the Rhine and the ocean are opposed to each other, each disputing the ground now occupied by Holland ; the one striving to shape, out an estuary, the other to form a delta. There was evidently a period when the river obtained the ascendency, but for the last two thousand years, during which man has witnessed and actively participated in the struggle, the result has been in favour of the ocean, the area of the whole territory having become more and more circumscribed ; natural and artificial barriers having given way, one after another, and many hundred thousand human beings having perished in the waves.

The Rhine, after flowing from the Grison Alps, copiously charged with sediment, first purges itself in the Lake of Constance, where a large delta is formed : then, swelled by the Aar and numerous other tributaries, it flows for more than six hundred miles towards the north; when, entering a low tract, it divides into two arms, not far north of Cleves—a point which must therefore be considered the head of its delta.