mixed among the larger pebbles we might expect to find any animal bones that had been lying on the land contiguous to the stream, or any of the larger and heavier objects of human workmanship, that would have been carried off by such an inundation, had mankind been living on the banks of the river.
Were men, or any of the larger animals overwhelmed and drowned by the flood, it seems probable that, owing to the slight difference between their specific gravity and that of water, they would eventually have been carried down to the sea, unless by some means accidentally arrested in their course, or carried into the more stagnant waters. In either case, they would, on the waters subsiding, probably be exposed on or near the surface, and not be imbedded in any of the deposits of the stream. Assuming the existence at that time of a respect for the dead, such as may be regarded as almost instinctive in man, any human remains would be buried or otherwise disposed of, while the bones of the other carcases would be left within reach of the waters, should another flood occur.
At the mouth of the river, where it joined the sea, its excavating power would be considerably greater than farther inland; for at first, on account of the land having—as was presumed, in this hypothetical case—risen faster than the river could excavate its valley, the stream must have fallen as a cascade into the sea. This, by the cutting back of the lip in such a soft rock as the Chalk, would soon be converted into a rapid, where the greater velocity of the water would much add to its erosive power; and, ere long, a mouth to the river would be formed, which would soon become tidal. Before tracing the results that would be due to this greater declivity of the river-bed in the immediate neighbourhood of the sea, it will be well to consider what would be the results of successively recurring floods, in the less inclined broad shallow valley, on which we have been speculating.
There can be no doubt that with each succeeding flood the valley would be deepened; and the fact of its being thus deepened would tend to make it narrower, by restricting the windings of the river. We can, however, hardly imagine that in this deepening process the whole of the deposits spread by the former floods over the bottom and slopes of the valley would be removed, but must acknowledge the extreme probability of some portions of them having remained intact, especially those which were left at the greatest distance from the course eventually taken by the river
