Page:Encyclopædia Britannica, Ninth Edition, v. 8.djvu/712

Rh G82 EUROPE facilities for maritime activity are exceptionally great. That so small a part of the total belongs to the Arctic Ocean, which lies ice-bound during many mouths of the year, and so large a part to the Mediterranean, with its comparative freedom from winter and storm, has been of no small im portance to the progress of the European peoples. Changes T ^ e coast-line of Europe is in its general features very of coast- much the same as it was at the commencement of the true line. historic period ; but when it is examined in detail it is found to have undergone a number of important local changes, some at least of which are due to causes that are at work over very extensive areas. These changes may be conve niently classified under four heads: the formation of deltas by the alluvium of rivers ; the increase of the land-surface due to upheaval ; the advance of the sea by reason of its ovn erosive activity ; and the advance of the sea through the subsidence of the land. The actual form of the coast, however, is frequently due to the simultaneous or successive action of several of the causes sea and river and subter ranean forces helping or resisting each other. Our informa tion is naturally most complete in regard to the Mediter ranean coasts, as these were the best known to our first book- writing nations. There we find that all the great rivers have been successfully at work more especially the Rhone, the Ebro, and the Po. The activity of the Rhone, indeed, as a maker of new land, is really astonishing. The tower of St Louis, erected on the coast in 1737, is now upwards of four miles inland; the city of Aries is said to be nearly twice as far from the sea as it was iu the Roman period. The present St Gilles was probably a harbour when the Greeks founded Marseilles, and Aigues Mortes, which took its place in the Middle Ages, was no longer on the coast in the time of St Louis. According to a calculation quoted by M. Reclus, the total alluvium of the river in the space of a year is 17,000,000 cubic metres, or 590,000,000 cubic feet; and this estimate is supported by M. Reybert, who found that the new laud formed between 1841 and 1853 implied an annual deposit of nearly 19,000,000 cubic metres, or 671,000,000 cubic feet. The increase of the land is observ able, not only in the immediate neighbourhood of the mouth, but round almost the whole of the gulf of Lyons, and is, of course, partly due to the alluvium of minor rivers. At the mouth of the Herault, according to Fischer, 1 the coast advances at least two metres or about seven feet annually ; and it requires great labour to keep the harbour of Cette from being silted up. The Po is even more efficient than the Rhone, if the size of its basin be taken into ac count. Were it not counteracted in some measure, it would soon, with the assistance of the Isonzo, the Adige, and the neighbouring streams, turn the northern part of the Adriatic into a plain. Ravenna, which was at one time an insular city like Venice, has now a wide stretch of downs partly covered with pine forest between it and the sea. Aquileia, one of the greatest seaports of the Mediterranean in the early centuries of the Christain era, is now 7 miles from the coast, and Adria, which gives its name to the sea, is 13. And this increase of the land has gone on in spite of the fact that both cities are on the northern part of an area of subsidence which apparently extends southwards along the whole Dalmatian coast. The islands on which Venice is built have sunk about three feet since the IGth century : the pavement of the square of St Mark s has frequently re quired to be raised, and the boring of a well has shown that a layer of vegetable remains, indicating a flora identical with that observed at present on the neighbouring main land, exists at a depth of 400 feet below the alluvial de posits. At Zara ancient pavements and mosaics are found 1 &quot; Kiisienveranderungen im Mittelmeergebiet,&quot; iu Ztschr. der Get. fur Erdkunde zu Berlin, 1878, below the sea-level, and the district at the mouth of the Narenta has been changed into a swamp by the advance of the sea. A process of elevation, on the other hand, is indicated along nearly all the coasts of Sicily, round the bay of Naples and the bay of Gaieta, at the southern end of Sardinia, the east of Corsica, and perhaps iu the neigh bourhood of Nice. The borings of pholads are found at a height of 600 feet on Monte Pellegrino ; the ancient harbour which gave its name to Palermo (Pauormus) is now nearly covered by the modern town ; and the Grotto of San Giro, which now lies 6000 feet inland, and at a height of more than 220 feet, must have had a direct com munication with the sea during the period of human occu pation. That the rise thus rendered evident is taking place over a wide area is shown by similar facts observed on the African coast. The Tunisian harbour of Porto Farina, which had a depth of 30 or 40 feet in last century, can hardly be trusted for 2 ; and this change can only be very partially due to the action of the Medjenda river, as it brings down but little alluvium. If the movement be maintained the Mediterranean will again be divided into two basins by the old ridge between Sicily and Africa whose existence has been posited to explain the present distribution of zoological fossils. Passing eastward to the Balkan peninsula, we find considerable changes on the coast-line of Greece ; but as they are only repetitions on a smaller scale of the phenomena already described, it is sufficient to indicate the Gulf of Arta and the mouth of the Spercheius as two of the more im portant localities. The latter especially is interesting to the historian as well as to the geologist, as the river has greatly altered the physical features of one of the world s most famous scenes the battle-field of Thermopyla3. If we proceed to the Atlantic seaboard we observe, as we might expect, great modifications in the embouchures of the Garonne and the Loire, but by far the most remarkable oscillations of sea and land have taken place in what are emphatically the Low Countries of Europe. It is one of the familiar facts of geography that a large par,t of the soil of Holland with its villages and cities is many feet below the level of the sea; but it is not so generally known that about a fifth of the area of the country is thus situated. The story of the contest carried on along the coast between man and nature has often been told, and is well worth the telling. If success is to be measured by the amount of territory acquired, nature has hitherto had the best of the battle, and no wonder, if it be true that the very ground on which man has built his ramparts against the sea is slowly sinking under his feet. Such, at least, is the opinion of Elie de Beaumont and other geologists of note : in fact the whole maritime region from the Scheldt to the Weser is an area of subsidence. The Dutchman, however, does not intend to give up the contest. It was only in 1395 that he finally lost possession of the 500,000 hectares or 1,236,570 English acres of good land which are now covered by the Zuyder Zee ; and he hopes to get the best part of it back again. A scheme has been proposed by which the whole southern portion, with an area of 195,000 hectares (481,872 acres) will be inclosed by a dyke extending from Enkhuizen to Karnpen; and thefeasibilityof the enterprise is sufficiently attested by the brilliant success of the Haarlem engineers who, at a cost of less than 765,000, have recovered the area of the Haarlem Lake w r hich had been lost in the 16th century. Further east along the coast, between the Elbe and the Eider, it is hard to say whether land or sea is gaining : on the one hand it is stated that the ruins of the castle of chlei are now covered by the sea, and that a forest of historic identity is totally destroyed ; while on the other it is equally certain that the parish of Busum in the north part of Ditmarsh was made land-fast only in the 16th century, that the Friedrick Koog, an area of new alluvial laud five