CHAPTER IV.

REMARKS ON THE GERMAN OCEAN CONTINUED.—ITS RESTORATIVE POWERS ON OTHER COASTS DEMONSTRATED.—INCREASE OF THE SHOALS OF SAND OFF HASBOROUGH, CAISTER, &C.—THE SMALLER SHOALS OF SAND ALONG THE COAST—THEIR FORMATION AND EFFECTS CONSIDERED.

HAVING now brought together ample proofs of the destructive operations of the waves, tides, and currents upon our eastern coast, let us observe examples of their restorative power, in many instances aided and assisted by the hand of man.

The German Ocean is deepest on the Norwegian side, where the soundings give one hundred and ninety fathoms; but the mean depth of the whole basin may be stated at no more than thirty-one fathoms. {36} The bed of this sea is traversed by several enormous banks: one of which, occupying a central position, trends from the Frith of Forth in a north-easterly direction, to a distance of one hundred and ten miles; others run from Denmark and Jutland, upwards of one hundred and five miles to the north-west; while the greatest of all, the Dogger Bank, extends for upwards of three hundred and fifty-four miles from north to south. {37a} The whole superficies of these enormous shoals is equal to about one-fifth of the whole area of the German Ocean, or to about one-third of the whole extent of England and Scotland. {37b} The average height of the banks measures, according to Mr. Stevenson, about seventy-eight feet; the upper portion consisting of fine and course silicious sand, mixed with comminuted corals and shell. {37c} Some long narrow ravines are found to intersect the banks. One of these varies from seventeen to forty-four fathoms in depth and has very precipitous sides: in one part, called the “Inner Silver Pits,” it is fifty-five fathoms deep. The shallowest parts of the Dogger Bank were found to be forty-two feet under water, except in one place, where the wreck of a ship had caused a shoal.

These sands receive fresh increase every day; so that in time the place bids fair to become habitable earth.

The kingdom of Holland seems to be a conquest upon the sea, and in a manner rescued from its bosom. The surface of the earth, in this country, is below the level of the bed of the ocean; and I remember, observes Buffon, upon approaching the coast, to have looked down upon it from the sea, as into a valley: however, it is every day rising higher by the depositions made upon it by the sea, the Rhine and the Meuse, and those parts which formerly admitted large men of war, are now known to be too shallow to receive ships of very moderate burden.

The formation of new lands by the sea’s continually bringing its sediment to one place, and by the accumulation of its sands in another, is easily conceived. We have had many instances of this in England. The island of Oxney, which is adjacent to Romney-marsh, was produced in this manner. This had for a long time been a low level, continually in danger of being overflown by the river Rother; but the sea, by its depositions, has gradually raised the bottom of the river, while it has hollowed its mouth; so that the one is sufficiently secured from inundations, and the other is deep enough to admit ships of considerable burthen.

On many parts of the coasts of France, England, Holland, Germany, and Prussia, the sea has been sensibly known to retire. {38a}

Instances of new lands having been produced from the sea are brought about by two different ways; first, by the waters raising banks of sand or mud where the sediment is deposited; and, secondly, by their relinquishing the shore entirely, and leaving it unoccupied to the industry of man. {38b}

The quantity of sand, stones, &c., moved here and there by the tidal current is very considerable, and no given line of the coast can afford a better example than the one under consideration.

The Hasborough Sands probably increase in breadth if not in length, since every year they receive fresh accessions from vessels buried in their vortex, which afford a nucleus for retaining the sand lodging against them.

The Cockle Sands, off Caistor, {39} have increased since 1836 one mile and a half in extent to the northward.

The deposition of sands, stones, shingle, &c., upon our coast, especially during the summer months, when easterly, southerly, and westerly winds prevail, would strike the beholder unaccustomed to witness the contrary effects, as an apparent impossibility, that the water could remove such an immense quantity of material especially in the short time that it does when a north-west gale prevails.

Shoals of sand of various length, breadth, and depth, appear and disappear, form and re-form, in the offing.—In north-westerly gales only are they solid, stable, and compact, and increase in breadth, while the materials on the beach are swept away. They extend in a direction parallel with the shore, and present an inclined plane, on each side of their base a corresponding shallow exists, and the tidal current will not allow materials to rest on their surface sufficiently to increase their elevation, and render them more efficient. As it is, however, they are natural breakwaters, but from their irregularity in extent, dimensions, and situation, they afford only a partial protection to the coast.

The incursions of the sea at Aldborough, in Suffolk, were formerly very destructive; and this borough is known to have been once situated a quarter of a mile east of the present shore. The inhabitants continued to build further inland, till they arrived at the extremity of their property, and then the town decayed greatly; but two sandbanks thrown up at a short distance, now afford a temporary safeguard to the coast. Between these banks and the present shore, where the current now flows, the sea is twenty-four feet deep on the spot where the town formerly stood.

Immediately off Yarmouth, {40a} and parallel to the shore, is a range of sand-banks, the shape of which varies slowly from year to year, and often suddenly after great storms. The late Captain Hewett, R.N., found in these banks, in 1836, a broad channel sixty-five feet deep, where there was only a depth of four feet during a prior survey in 1822. The sea had excavated to the depth of sixty feet in the course of fourteen years, or perhaps a shorter period. {40b}

Wherever a shoal of sand exists in the offing, at a distance beyond where the ebbing of the tide recedes to its greatest extent, denominated low water mark, there the innermost shallow will probably be: another shoal immediately forms, the base commencing at low water mark, and a gradual rise takes place towards the cliffs, terminating at or beyond the extent of the flowing of the tide denominated high water mark. Here, then, the shoal will be more efficient; the tidal wave and current will be checked and broken against the ascending bank.

But should a shoal of sand form whose superior surface terminates at low water mark, the innermost shallow {41} will be observed nearer to, and its course frequently terminate in, an angular direction to the cliffs; and between the intermediate spaces of the shoals existing in the offing, a current frequently sets in towards the shore, which will aid the force of the tidal wave and current, when called into excessive action, in its attack either upon the cliff opposite, or a partial shoal nearest it. Under these circumstances, the one will soon lose its inclined surface, and the other will become undermined.

Where shoals of sand exist in the offing, there the beach is widest, and where they do not exist, there the beach is narrowest.