Similar appearances occur on other coasts. Between the coasts of Norfolk and Zealand in Holland, there is a great sand-hank, where opposite currents meet, and it is probable that this bank will in time form an island, and probably even an isthmus. Much of the country of the United Provinces has been produced by the form ing action of the sea.
A great portion of the flat country from the mouth of the Rhone to the Pyrenees is said to he the work or the ocean ; and the whole tract of country from Pisa to Leghorn is a formation of the same nature.
In those putts of the sea where its waters are but lit tle agitated, similar forming effects arc to be observed.
Where marine currents flow rapidly, and near the coast, they exert a destroying power, but when they act at a distance, a forming power.
The effects produced by the sea alone, without the aid of rivers, are far less beneficial. When the sea coast is low, and the bottom consists of sand, the waves push this sand towards the shore, where, at every reflux of the tide, it becomes partially dried ; and the winds, which almost always blow from the sea, drift up some portion of it upon the heuch. By this means downs, or ranges of low sand hills, are formed along the coast. These, if not fixed by the growth of suitable plants, either denominated by nature, or propagated by human industry, would be gradually, but certainly, carried to wards the interior, covering up the fertile plains with their sterile particles, and rendering them unfit for the habitation of mankind, because the same winds which carried the loose dry sand from the shore, to form the downs, would necessarily continue to drift that which is at the summit further towards the land. On the east coast of Scotland, and in many of the islands, there are striking effects of this kind. Dr Luc, the brother, in the Mercure de France, communicates the following in teresting statement in regard to the progress of the blowing sand, termed the sand flood in Egypt : " The sands of the Lydian desert," he says, " driven by the west winds, have left no lands capable of tillage on any parts of the western banks of the Nile not shel tered by mountains. The encroachment of these sands on soils ee hich were formerly habited and cultivated is evidently seen. I11 Denon informs us. in the account of his Travels in Lower and Ulzper Egypt, that sum mits of the ruins of ancient cities, buried under these sands, still appear externally ; and that, but for a ridge of mountains called the Lybian chain, which borders the left bank of the Nile, and lorms, in the parts where it rises, a barrier against the invasion of these sands, the shores of the river, on that side, would long since have ceased to be habitable. Nothing can be more melan choly," says this traveller, " than to walk over villages swallowed up by the sand of the desert, to trample un der foot their roofs, to strike against the summits of their minarets, to reflect that yonder were cultivated fields, that there grew trees, that here were even the dwellings of men, and that all has vanished.
" If then our continents were as ancient as has been pretended, no traces of the habitation of men would ap pear on any part of the western bank of the Nile, which is exposed to this scourge of the sands of the desert. The existence, therefore, of such monuments attests the successive progress of the encroachments of the sand ; and these parts of the bank, formerly inhabited, will lor ever remain arid and waste. Thus the great population of Egypt, announced by the vast and nume rous ruins of its cities, was in great part due to a cause of fertility which nn longer exists, and to which suffi cient attention has not been given. The sands of the desert were formerly remote from Egypt; the Oases, or habitable spots, still appearing in the midst of the sands, being the remains of the soils formerly extending the whole way to the Nile ; but these sands. transported hither by the western winds, have overwhelmed and buried this extensive tract, and doomed to sterility a land which was once remarkable for its fruitfulness.
" It is therefore not solely to her revolutions and changes of sovereigns that Egypt owes the loss of her ancient splendour ; it is also to her having been thus irrecoverably deprived of a tract of land, by which, be fore the sands of the desert had covered it and caused it to disappear, her wants had been abundantly supplied. Now, if we fix our attention on this fact, and leflect on the consequences which would have attended it if thou sands, or only sorne hundreds of centuries had elapsed since our continents first existed above the level of the sea, does it not evidently appear that all the country on the west of the Nile would have been buried under this sand before the erection of the cities of ancient Egypt, how remote soever that period may be supposed ; and that, in a country so long afflicted with sterility, no idea would even have been formed of constructing such vast and numerous edifices ? When these cities indeed were built, another cause concurred in favouring their pros perity. The navigation of the Red Sea was not then attended with any danger on the coasts; all its ports, now nearly blocked up with reefs of coral, had a safe and easy access; the vessels laden with merchandize and provisions could enter them and depart without risk of being wrecked on these shoals, which have risen since that time, and are still increasing in extent.