The breakers of the ocean—Caverns and fairy bridges of Kilkee—Italy and Sicily—The Shetland Islands—East and south coast of Britain—Tracts of land swallowed up by the sea—Island of Heligoland—Northstrand—Tides and currents—South Atlantic current—Equatorial current—The Gulf Stream—Its course described—Examples of its power as an agent of transport.

While the rain, the rivers, and the streams, are thus wasting away the mountains and plains of the interior country, the waves of the sea are exerting a power no less destructive on the coasts of islands and of continents. The breakers dashing against the foot of a lofty cliff, dissolve and decompose and wear away the lower strata; and the overhanging rocks, thus undermined, fall down in course of time by their own weight. With the next returning wave these rocks are themselves hurled back against the cliff; and so, as some one has happily remarked, the land would seem to supply a powerful artillery for its own destruction. The effects of the breakers are often very unequal, even on the same line of cliffs. Some parts of the rock are more yielding than others, or perhaps they are more exposed to the action of the waves, or perhaps they are divided by larger joints and more freely admit the destructive element. These parts will be the first to give way, while the harder and less exposed rock will be left standing: and in this way forms the most capricious and fantastic are produced.

No finer examples could be wished for than those which are seen in the neighborhood of Kilkee, and along the promontory of Loop Head, in the county of Clare. Sometimes the ground is undermined with caverns, into which, when the tide is coming in, the waves of the Atlantic rush with resistless force, making new additions each day to the accumulated ruins of ages. Sometimes lofty pinnacles of rock are left standing in the midst of the waters, like giant sentinels stationed there by Nature to guard the coast. In one or two instances these isolated fragments are connected with the main land by natural arches of rock, which are called fairy bridges by the people; but more commonly they appear as rocky islets, and answer exactly to the poet’s description—

It is interesting to observe in passing, that, in the original verses of the Æneid, of which these lines are Dryden’s translation, Virgil has recorded a belief which prevailed in his time, and which, upon scientific grounds, is now regarded as highly probable by Geologists, that the island of Sicily had been once connected by land with Italy, and was separated from it by the action of the waves:

But whatever may be thought of this opinion thus rendered immortal by the genius of the poet, we shall not stop to discuss its merits. For in the present stage of our argument, it is our object to deal, not with vague and uncertain traditions, nor even with philosophical speculations, but rather with the facts which are actually going on in nature, and which any one of our readers may examine for himself. With this object in view, we shall take a few examples from the Eastern and Southern coasts of Great Britain, which have been carefully explored by scientific men for the purpose of observing and recording the amount of destruction accomplished by the waves within recent times.

The Shetland Islands, exposed to the whole fury of the Atlantic, present many phenomena not unlike those of Kilkee and Loop Head, but upon a far grander scale. Whole islands have been swept away by the resistless power of the waters, and of others nothing remains but massive pillars of hard rock, which have been well described as rising up “like the ruins of Palmyra in the desert of the ocean.” Passing to the mainland, it is recorded that in the year 1795 a village in Kincardineshire was carried away in a single night, and the sea advanced a hundred and fifty yards inland, where it has ever since maintained its ground. In England, almost the whole coast of Yorkshire is undergoing constant dilapidation. On the south side of Flamborough Head the cliffs are receding at an average rate of two yards and a quarter in the year, for a distance of thirty-six miles along the coast. This would amount to a mile since the Norman Conquest, and to more than two miles since the occupation of York by the Romans. It is not surprising, therefore, to learn that many spots marked in the old maps of the country as the sites of towns or villages, are now sandbanks in the sea. Even places of historic name have not been spared. The town of Ravenspur, from which, in 1332, Edward Baliol sailed for the invasion of Scotland, and at which Henry the Fourth landed in 1399, to claim the throne of England, has long since been swallowed up by the devouring element.

On the coast of Norfolk it was calculated, at the beginning of the present century, that the mean loss of the land was something less than one yard in the year. The inn at Sherringham was built on this calculation in 1805, and it was expected to stand for seventy years. But unfortunately the actual advance of the sea exceeded the calculation. Sir Charles Lyell, who visited this spot in 1829, relates that during the five preceding years seventeen yards of the cliff had been swept away, and nothing but a small garden was then left between the building and the sea. The same distinguished writer tells us that in the harbor of this town there was at that time water sufficient to float a frigate where forty-eight years before had stood a cliff fifty feet in height with houses built upon it. And remarking upon these facts, he says, that “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.”

In the neighborhood of Dunwich, once the most considerable seaport on the coast of Suffolk, the cliffs have been wasting away from an early period of history. “Two tracts of land which had been taxed in the time of King Edward the Confessor, are mentioned in the Conqueror’s survey, made but a few years afterward, as having been devoured by the sea.” And the memory of other losses in the town itself—including a monastery, several churches, the town-hall, the jail, and many hundred houses—together with the dates of their occurrence, is faithfully preserved in authentic records. In 1740 the sea reached the churchyard of Saint Nicholas and Saint Francis, so that the graves, the coffins, and the skeletons, were exposed to view on the face of the cliffs. Since that time the coffins, and the tombstones, and the churchyard itself, have disappeared beneath the waves. Nothing now remains of this once flourishing and populous city but the name alone, which is still attached to a little village of about twenty houses. The spot on which the Church of Reculver stands, near the mouth of the Thames, was a mile inland in the reign of Henry the Eighth; in the year 1834 it was overhanging the sea; and it would long ago have been demolished, but for an artificial causeway of stones constructed with a view to break the force of the waves. It is estimated that the land on the northeast coast of Kent is receding at the rate of about two feet in the year. The promontory of Beachy Head in Sussex is also rapidly falling away. In the year 1813 an enormous mass of chalk, three hundred feet in length and eighty in breadth, came down with a tremendous crash; and slips of the same kind have often occurred, both before and since.

To these examples from Great Britain we may add one or two from the German Ocean. Seven islands have completely disappeared within a very narrow area since the time of Pliny; for he counted twenty-three between Texel and the mouth of the Eider, whereas now there are but sixteen. The island of Heligoland, at the mouth of the Elbe, has been for ages subject to great dilapidation. Within the last five hundred years three-fourths of it have been carried away; and since 1770 the fragment that remains has been divided into two parts by a channel which is at present navigable for large ships. A still more remarkable instance of destruction effected by the waves of the sea occurred in the island of Northstrand, on the coast of Schleswig. Previous to the thirteenth century it was attached to the mainland, forming a part of the continent of Europe, and was a highly cultivated and populous district about ten miles long, and from six to eight broad. In the year 1240 it was cut off from the coast of Schleswig by an inroad of the sea, and it gradually wasted away up to the seventeenth century, when its entire circumference was sixteen geographical miles. Even then the industrious inhabitants,—about nine thousand in number,—endeavored to save what remained of their territory by the erection of lofty dykes; but on the eleventh of October, 1634, the whole island was overwhelmed by another invasion of the sea, in which 6000 people perished, and 50,000 head of cattle. Three small islets are all that now remain of this once fertile district.25

The breakers of the ocean receive no small aid in their work of destruction from the action of tides and currents which co-operate with the winds to keep the waters of the sea in constant motion. And though the winds may sleep for a time, the tides and currents are always actively at work, and never for a moment cease to wear away the land. But they are even more powerful auxiliaries as agents of transport. If it were not for them, the ruins which fall from the rocks to-day would to-morrow form a barrier against the waves, and the work of destruction would cease. But Nature has ordained it otherwise. When the tide advances, it rolls the broken fragments toward the land, and when it recedes, it carries them back to the deep; and so by unceasing friction these fragments are worn away to pebbles, and then, being more easily transported, they are carried off to sea and deposited in the bed of the ocean: or else, perhaps, they are cast up on the sloping shore, to form what is so familiar to us all under the name of a shingle-beach.

This is a subject on which it is needless to enlarge. Every one knows that the tides have the power of transporting solid matter; though most of us, perhaps, do not fully appreciate the magnitude of their accumulated effects, working as they do with untiring energies upon the coasts of islands and continents all over the world. It is not, however, so generally known that the ocean is traversed in all directions by powerful currents, which, from their regularity, their permanence, and their extent, have been aptly called the rivers of the ocean. We do not mean here to inquire into the causes of these currents, upon which the progress of physical science has thrown considerable light: neither can we hope to describe even the principal currents that prevail over the vast tracts of water which constitute about three-fourths of the entire surface of our globe. We shall content ourselves with tracing the course of one great system, which may serve to give some idea of their general character and enormous power.

This system would seem to have its origin with a stream that flows from the Indian Ocean toward the southwest, and then doubling the Cape of Good Hope, turns northward along the African coast. It is here called the South Atlantic Current. When it encounters the shores of Guinea, it is diverted to the west, and stretches across the Atlantic, traversing forty degrees of longitude until it reaches the projecting promontory of Brazil in South America. In this part of its course it is known as the Equatorial Current, because it follows pretty nearly the line of the Equator: it varies in breadth from two hundred to five hundred miles, and it travels at the mean rate of thirty miles a day, though sometimes its velocity is increased to seventy or eighty. Next, under the name of the Guyana Current, it pursues a northwesterly direction, following the line of the coast; and passing close to the island of Trinidad, becomes diffused, and almost seems to be lost, in the Caribbean Sea. Nevertheless, it again issues with renewed energy from the Gulf of Mexico, and rushing through the Straits of Florida at the rate of four and five miles an hour, it issues once more into the broad waters of the Atlantic. From this out it is called the Gulf Stream, and is well known to all who are concerned in Transatlantic navigation; for it sensibly accelerates the speed of vessels which are bound from America to Europe, and sensibly retards those sailing from Europe to America.

The Gulf Stream, however, does not set out on its Transatlantic voyage directly that it issues from the Straits of Florida. It keeps at first a northeasterly course, following the outline of the American continent, passing by New York and Nova Scotia, and brushing the southern extremity of the great Newfoundland Bank. Then taking leave of the land, it sweeps right across the Atlantic. After a time it seems to divide into two branches, one inclining to the south, and losing itself among the Azores, the other bending toward the north, washing the shores of Ireland, Scotland, Norway, and reaching even to the frozen regions of Spitzbergen. The breadth of the Gulf Stream, when it issues from the Straits of Florida, is about fifty miles, but it afterward increases to three hundred. Its color is a dark indigo blue, which, contrasting sharply with the green waters of the Atlantic, forms a line of junction distinctly visible for some hundreds of miles: afterward, when this boundary line is no longer sensible to the eye, it is easily ascertained by the thermometer; for the temperature of the Gulf Stream is everywhere from eight to ten degrees higher than that of the surrounding ocean.26

We leave our readers to infer from this brief description how immense must be the power of transport which belongs to such currents as these. They sweep along the shores of continents, and carry away the accumulated fragments of rock, which had first been rent from the cliffs by the waves of the sea, and then borne out to a little distance by the tides: they pass by the mouths of great rivers, and receiving the spoils of many a fertile and populous country, and the ruins of many an inaccessible mountain ridge, they hurry off to deposit this vast and varied freight in the deep abysses of the ocean. There is one circumstance, however, which we ought not to pass over in silence; for it is of especial importance to the Geologist, and might easily escape the notice of the general reader. It is a well ascertained fact that plants and fruits and other objects from the West Indian Islands are annually washed ashore by the Gulf Stream on the northwestern coasts of Europe. The mast of a man-of-war burnt at Jamaica was after some months found stranded on one of the Western Islands of Scotland;27 and General Sabine tells us that when he was in Norway, in the year 1823, casks of palm-oil were picked up on the shore near the North Cape, which belonged to a vessel that had been wrecked the previous year at Cape Lopez on the African coast.28 It seems most probable that these casks of oil must first have crossed the Atlantic from east to west in the Equatorial Current, then described the circuit of the West Indian Islands, and finally coming in with the Gulf Stream, recrossed the Atlantic, performing altogether a journey of more than eight thousand miles. From these facts it is clear that, by the agency of ocean currents, the productions of one country may be carried to another that is far distant. And Geologists do not fail to make use of this important conclusion when they find the animal and vegetable remains of different climates associated together in the same strata of the Earth.