ENCROACHMENTS OF THE SEA,

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The eastern coast of England has been greatly changed by the action of the waves, the ancient sites of towns and villages, being now sand banks in the sea. The whole coast of Yorkshire, from the mouth of the Tees to that of the Humber, is in a state of comparatively rapid decay; the inroads of the sea at different points being limited by the nature of the soil, or the hardness of the rocks. Pennant, after speaking of the silting up, or filling up with water transported sand, clay, gravel, &c., of some ancient posts in the estuary of the Humber, observes, "But in return, the sea has made most ample reprisals, the site, and even the very names of several places, once towns of note on the Humber, are now only recorded in history; Ravensper was at one time a rival to Hull, and a post so very considerable in 1332, that Edward Baliol, and the confederated English barons, sailed from hence to invade Scotland; and Henry IV. in 1399, made choice of this port to land at, to effect the deposal of Richard II; yet the whole of this has long since been devoured by the merciless ocean; extensive sands, dry at low water, are to be seen in its stead." Instances like these are not rare, the towns of Cromer, and Dunwich, are both lost, swallowed up by the ocean, which is now encroaching at Owthone at the rate of about four yards a year. At Sherringham, in Norfolkshire, where the present inn was built in 1805, and the sea was a distance of fifty yards, the mean loss of land being about one yard annually, it was calculated that it would require about seventy years before the sea would reach that spot, but between the years 1824 and 1829 no less than seventeen yards were swept away, and a small garden only, was left between the house and the sea, and when Mr. Lyell in 1829 visited the place, he found a depth of twenty feet, (sufficient to float a frigate), where, only forty-eight years ago, stood a cliff fifty feet high. Mr. Lyell justly remarks, If once in half a century an equal amount of change were produced suddenly, by the momentary shock of an earthquake, history would be filled with records of such wonderful revolutions of the earth's surface; but if the conversion of high land into deep sea be gradual it excites only local attention." The flag-staff of the Preventive Service station, on the south side of the harbor, has, within

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the last fifteen years, been thrice removed inland, in consequence of the advance of the sea.

Along the whole eastern coast of England, changes similar to these are going on. In some places by the silting up of estuaries, land is forming, but not near as much, as is being removed. The isle of Sheppey, which is a tertiary formation, now about six miles long, by four in breadth, is rapidly decaying on its north side, fifty acres of land having been lost within the last twenty years. To the east of Sheppey stands the Church of Reculver, upon a cliff of clay and sand, about twenty-five feet high. This place was formerly an important military station in the time of the Romans, and even so late as the reign of Henry VIII, was nearly one mile distant from the sea.

We here give a view of the Church of Reculver taken in the year 1781, copied from the Gentleman's Magazine. At this time the spot had become interesting from the encroachment of the water. It represents considerable space as intervening between the churchyard and the cliff. In the year 1782, the cottage at the right was demolished; nearer the church is shown an ancient chapel now destroyed, and at the extreme right is the Isle of Sheppey. In the year 1806, a part of the Churchyard with some

of the adjoining houses was washed away, and the ancient church with its two lofty spires, a well known land-mark, was abandoned. The following view of it as it appeared in 1834, is taken from Mr. Lyell's Principles of Geology, from which the preceding statement is also derived. This ancient building would.

probably, have fallen long since, had not the force of the waters been checked by an artificial causeway of stones, and large wooden piles, driven into the sands to break the force of the waves.

There are good reasons for believing that the coasts of France and England were formerly united, this is inferred from the identity of the composition of the cliffs on the opposite sides of the channel, and also of the noxious animals in England and France, which could hardly have been introduced by man. This opinion is advocated by many distinguished geologists, and it is by no means incredible, that in the course of ages the sea may have forced its passage through. The separation of Friesland, which was once a part of North Holland, from the mainland, by the action of the

sea in the thirteenth century, and the formation of a strait of about half the width of the English channel in 100 years, lends countenance to this opinion. The inroads of the sea have no where been more severe than in Holland, and even at the present day 12,000 windurills are employed to drain the Netherlands and to prevent at least two-thirds of the kingdom from returning to the state of bog and morass, and during the past year three immense steam engines, capable of discharging 2,800,000 tons of water in 24 hours, have been employed in pumping out aud emptying through the great ship canal, and sea-sluices at Katwyk, the lake of Haarlem, which by its continual inroads threatened to inundate Amsterdam on the one side, and Leyden on the other. In the year 1836, twenty-nine thousand acres of land were completely overflowed by it. The large lake called the Bies Bach was formed in 1621, by the sea bursting through the embankments of the river Meuse, overflowing seventy-two villages. Of these villages no vestiges of thirty-five of them were ever discovered. Since their destruction an alluvial deposit has been formed partly over their site. The island of Northstrand, which

in the year 1634, contained 9000 inhabitants, and was celebrated for its high state of cultivation, was, on the evening of the 11th of October, in that year, swept away by a flood which destroyed 1300 houses, 50,000 head of cattle, and 6000 men, leaving three small islets, one of them still called Northstrand, which are continually being wasted away by the sea. Such are some of the powerful effects of currents and waves in altering, and finally sweeping away the headlands and islands which at any particular epoch may have distinguished the line of coast exposed to their force; the eastern side of America, along the Atlantic coast is subject to the same changes. Before leaving this part of our subject, we will describe that peculiar tidal wave called "the Bore." This is produced, when the channel of a river, into which the tidal wave from the ocean is entering, is so narrow that the water is made to rise suddenly, and thus terminates abruptly on the side away from the sea, or infand; precisely like the waves which break upon a shelving shore. As might be expected, this phenomenon occurs most powerfully at the time of spring, or high

est tides. The Bore which enters the river Severn is sometimes nine feet high, and at spring tides rushes up the estuary with extraordinary rapidity. In the Hoogly or Calcutta river, says Rennell, 66 the Bore commences at Hoogly point, the place where the river first contracts itself, and is perceptible above Hoogly town; and so quick is its motion, that it hardly employs four hours in traveling from one to the other, though the distance is nearly seventy miles. The tides of the Bay of Fundy pour twice a day vast bodies of water through a narrow strait, causing in every small stream, an immense tidal wave, rising sometimes to the height of seventy feet. We have already alluded to its rich alluvial deposits of red marl which have been excluded artificially from the sea by embankments,

Heretofore we have noticed only the degrading effects of currents, and tides. It might at first appear that the sediment borne down by rivers, the formation of deltas, and the silting up of estuaries, would compensate for the loss by the encroachments of the sea, this however, is not the case; while in all instances the new-made land is constantly attracting attention, there are no boundaries, or great atural land marks, to show where was formerly the line of coast. The former demand attention by their presence, the latter are unseen, and therefore lightly esti- · mated; many places where once flourishing cities stood, are now, not only depopulated, but covered with water to a depth of thirty feet. There is therefore good reason for believing that the loss of land by the effects of currents and tides, much more than counterbalances all deposited in the form of dry land.

The general tendency of these encroachments is undoubtedly to fill up the bed of the sea, and to finally reduce the surface of the earth to a uniform level; and this would ultimately be accomplished, but for the counterbalancing force of volcanic or igneous causes, which are continually elevating the surface. If we had space we might continue to enumerate examples of the effects of the ocean in destroying the coasts, not only of our own country, but over the whole world: sufficient however has been said to give some idea of the importance of these causes of change, and when hereafter, we allude to immense formations of rock