Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/278

 day, than to a sudden subsiding of the strata at a period of time far beyond the reach of all historical monuments.

If the chalk hills constitute ridges separated by low troughs or vales which have been filled up by alluvial depositions, may not the bottom of one of these vales have once existed in the space now occupied by the Southampton channel; and thus the separation of the Isle of Wight have taken place in consequence of an encroachment of the sea on a portion of little elevated land, the loose materials of which besides, could have presented but a feeble barrier to the repeated assaults of the sea?

May not that narrow arm of the sea, which from Cowes-harbour extends four miles inland to Newport, and which is improperly called Medina river, be owing to a cause of that kind; as also that other still deeper arm of the sea which from Yarmouth runs to Freshwater-gate, and makes almost a complete island of that portion of the land which lies westward?

The shape of this channel, and its slanting declivity on both sides, affords also a further presumption of the truth of this hypothesis.

That I have not gone beyond the warrant of the facts in admitting such a disposition, as has been described, of chalk-hills with vales between them, may, I think, be clearly demonstrated from actual observations.

In Kent and Sussex are two ranges of chalk hills, the north and south downs, with an alluvial vale between them. In Hampshire, near Alresford, where the chalk begins to crop out, we pass over a ridge of this rock in a transverse direction to its length; till near