The German sea must have acted in the same manner against this isthmus, and the coasts of England and Flanders would convey its sediments into Holland and Zealand, the ground of which, though formerly covered with water, is now forty feet above. On the coast of England, the German sea must have filled up that large valley, where the river Stour actually flows for more than 20 miles, beginning at Sandwich, passing Canterbury, Chatham, Chilham as far as Ashford. At this place the ground is much higher than it was formerly, since at Chatham the bones of an hippopotamus were found seventeen feet deep in the earth, together with anchors and marine shells.
It is very probable the sea may form new land, by bringing and depositing, at particular places, sand, earth, mud, &c. for in the island of Orkney, which is adjacent to Romney Marsh, there was a tract of low land continually in danger of being inundated by the river Rother; but in less than 60 years this ground has been considerably elevated by quantities of earth and mud being brought thither every tide, and the channel through which it enters, in less than fifty years has deepened so much as to admit of the reception of large vessels, whereas at that time it was a ford over which people might pass.
In this manner, the sand bank was formed which extends obliquely from the coast of Norfolk to that of Zealand. This bank forms that part where the tides of the German and French sea meet, since the isthmus has been broken, and where the earth and sand are deposited which are washed away from the coasts; nor is it by any means improbable but that in the course of time this bank may become an isthmus.[AR]
[AR] See Abridgment of Philosophical Transactions, vol. II. page 227.
There is a great appearance, says Ray, that the island of Great Britain was formerly joined to France, and formed part of that continent: but it is not known whether its separation was caused by an earthquake, an eruption of the ocean, or by the labour of man; but that this island formed part of the continent is evident, from the rocks and coasts of both being of the same nature, composed of the same matters, and exactly of the same height; the length of the rocks, along these coasts, are also nearly the same, about six miles on either side. The little breadth of the channel, which in this part is not more than twenty-four English miles, and its shallowness, comparatively with the neighbouring sea, is another reason to suppose that England has been divided from France by accident. We may add to these proofs, that there were formerly wolves and bears in this island; it is not to be presumed that they could swim over, nor that men transported such destructive animals; for in general we find the noxious animals of the continent in the adjacent islands, and never in those which are separated from them by a great distance; as the Spaniards remarked when they landed in America.[AS]
[AS] See Ray's Discourses, page 208.
In the reign of Henry I. King of England, a great inundation happened by an eruption of the sea in part of Flanders. In 1446 by a like eruption 10,000 persons were drowned in the territory of Dordrecht, and more than 100,000 round Dullart, Friezeland, and in Zealand. In these last two provinces upwards of 300 villages were overflowed; the tops of their towers and steeples are still to be seen rising out of the water.
From the coasts of France, England, Holland and Germany, the sea has retreated in many parts. Hubert Thomas relates, in his description of Liege, that the sea formerly surrounded the walls of the city of Tongres, which is now more than 35 leagues distant from it; this he proves by many eligible reasons, and, among others, he says; that in his time the iron rings, to which the ships were moored, were to be seen remaining in the walls. We may likewise look on as lands deserted by the sea, the fens of Lincoln in England, Provence in France, and which has also very considerably retreated from the mouth of the Rhone since the year 1665. In Italy a considerable tract of land has been gained at the mouth of the Arno; and Ravenna, formerly a sea-port, is no longer a maritime town. Holland appears to be an entire new country, where the surface of the earth is almost on a level with the sea, although the land is considerably elevated by the daily deposit of mud and earth from the Rhine, Maese, &c. for it was formerly computed that the ground of Holland was, in many places, 50 feet lower than the bottom of the sea.
It is asserted, that in the year 860, a furious tempest drove on the coast so great a quantity of sand that it shut up the mouth of the Rhine, near the Cat, and that this river inundated the whole country, tore up trees and houses, and, at last, emptied itself into the channel of the Maese. In 1421 another inundation separated the town of Dordrecht from the main land, submerged 72 villages, many castles, and drowned 100,000 souls, beside a great number of cattle. The dyke of Yssel was broken in 1638 by the ice brought down by the Rhine, which, having shut up the passage of the water, made an opening of some fathoms, and a great part of the province was overflowed before the breach could be repaired. In 1682 there was a similar inundation in the province of Zealand, which destroyed upwards of 30 villages, and drowned a considerable number of people and cattle, from their being surprised by the waters in the night. It was a fortunate circumstance for Holland that a south wind opposed the inroad of the sea, for it was so greatly swelled that the water was 18 feet higher than the highest ground of the province.[AT]
[AT] See the Historical Voyages of Europe, vol V. page 70.