even the land that had sustained them. By this dreadful calamity, there was swept away 1300 houses, with all the churches, 50,000 head of cattle, and more than 6000 people.

We might continue these accounts with regard to the changes which have taken place on the same coasts to great length; but our design being chiefly to give examples, rather than general details, we will here conclude this part of our subject.

DOWNS, OR SAND HILLS.

In some sections of country, the fine sand that is thrown up by the sea, is carried by the wind to considerable distances, and in such quantities as to cover the land entirely, and to fill up lakes and estuaries. Occasionally, also, there are sand plains at a distance from the sea, where vegetation seems never to have taken root, and where consequently, there is nothing to prevent the sand from spreading in all directions by the force of the winds.

On the coasts of France and Holland, long chains of sand hills have been formed from the sea, which have effected important geological changes, by barring up the mouths of rivers and bays, and thus preventing the ingress of tides, and changing the course of currents.

On the north coast of Cornwall, in England, a considerable extent of country has been inundated by drifting sand and pulverized shells from the sea shore. Some of the hills thus formed are several hundred feet high. By the shifting of these sands, the ruins of several ancient buildings have been discovered, shewing that these changes have been in progress for many centuries. In some places this sand has become so compact as to be employed for architectural purposes, the cementing agent being oxide of iron, which the water carries, in solution, from the upper to the lower strata.

But it is in the East, and especially on the borders of Egypt, that the devastating effects of sand has produced the most calamitious consequences. In Egypt, these are called sand floods, and of their effects De Luc has given the following statement:

"The sands of the Lybian," 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 sheltered by mountains. The encroachment of these sands on districts which were formerly inhabited and cultivated is evidently seen. M. Denon informs us in his Travels in Lower and Upper Egypt, that summits 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 forms, 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 melancholy," says Denon, "than to walk over villages, swallowed up by the sand of the desert, to trample under 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 have vanished."

De Luc draws an argument from these sand floods in favor of the newness of the earth, and of the truth of the Mosaic history of the Creation.

"If then," he continues, "our continents were as ancient as has been pretended, no traces of the habitation of men would appear 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 encroachment of the sand; and these parts of the bank formerly inhabited, will forever remain arid and waste."

"It is, therefore, not solely to her revolutions and changes of sovereigns, that Egypt owes the loss of her ancient splendor; it is also to her having been thus irrecoverably deprived of a tract of land, by which, before 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 reflect on the consequences which would have attended it, if thousands, or only some 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 favoring their prosperity. 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 merchandise 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." "Thus the reefs of coral which have been raised in the Red Sea, on the East of Egypt, and the sands of the desert which invade it on the west, concur in attesting this truth, That our continents are not of a more remote antiquity than has been assigned to them by the sacred historian, in the Book of Genesis, from the great era of the Deluge."

FORMATION OF CORAL ISLANDS.

It is but recently that any observations tending to interest or inform the naturalist, have been made on the production of Coral Islands. But the great extent to which these islands have been formed, together with the rapidity with which it has been said they are increasing, give this subject a considerable degree of interest, not only in respect to geology, but also as it regards com

merce.

On this subject Dr. Macculloch says, "The production of the Coral Islands of the great Pacific ocean, which endanger this navigation and that of the Indian Archipelago, and are tending fast to destroy that of the Red Sea, is a fact completely distinguished from all other subjects of geological investigation. It also forms a most interesting branch of the present inquiries; and it is the more indispensible to examine it, because it has hitherto been unaccountably neglected by other geological writers."

"It is sufficient here," he continues, to speak in the most general terms of a tribe of animals, for whose deIn a scription, works on Zoology must be consulted. popular view, a coral is a calcareous structure inhabited by numerous small animals or polypi; and each form of coral possesses its own species. Each, therefore, forms

a sort of colony, the inhabitants of which are disposed in minute cells, which they construct themselves, thus producing the general structure, by their joint labors as if all were actuated by one design and one mind."

"This is the obvious appearance. But in reality the entire coral plant is one animal. A continuous animal structure pervades the whole, and the calcareous matter in whatever form, must be viewed as the shell, being a secretion, or deposition of earth in its substance."-Geology, vol. i. p. 337.

The coral insects, of which there are many species, belong to the class POLYPI and order Coralliferi, of Cuvier. See Animal Kingdom, vol. iv. p. 387-95. They are a singular and curious tribe of animals, some of which are too minute to be examined by the naked eye.

The Coralliferi constitute that numerous suite of species which were formerly considered as marine plants, and of which the individuals are in fact united in great numbers to constitute compound animals, mostly fixed like plants; either forming a stem or simple expansions, by means of a solid internal substance. The individual animals are all connected by a common body, and are nourished in common, so that what is eaten by one goes to the nourishment of the general body of all the other polypi.-Animal Kingdom, ib.

The common coarse white coral, full of pores may be considered as an aggregate of the shells, or habitations of one family of these animals. On inspecting a piece of this substance while growing, or building under water, when these animals are at work, small whitish protuberances may be seen projecting from these pores, which being touched, or on removing the coral from the water, are seen to contract and disappear, but re-appear again when the coral is returned to the water. These are the animals which construct the coarse coral only. Those which build the compact kinds, as the red, white, and black, and which, (particularly the red,) are so much valued for ornamental purposes, are of a different species from these, and are so exceedingly minute as to be of difficult detection.

Many species of this tribe are free, and swim with the current, but those which produce the mighty effects about to be described are fixed in their cells. For an account of

these species, see Parkinson's Organic Remains, and Cuvier's Animal Kingdom.

It is for geography, not for a work of this nature, to describe the islands and rocks produced by the coral tribes. It is here sufficient to mention the islands south of the equator, between the West Coast of America, and New-Holland, crowding the whole of that sea, under a rapid increase, accompanied by still more numerous rocks, destined perhaps to become the seats of vegetations, and the habitations of man; perhaps at length to form a continent in the Pacific Ocean. To these, abounding particularly between New-Holland, New-Caledonia, and NewGuinea, I may add those of the Indian Archipelago, including Cosmoledo, Chagos, Juan de Nova, Armante, Cocos, and the Maldive, and Laccadive islands.

When we consider the feebleness of the means, and the minuteness of the agents, the extent of these reefs and islands is a subject of equal curiosity and surprise. Among these, Tongataboo is sixty miles in circumference and is elevated ten feet above the water. But this is but an insignificant work, when compared with the great coral reef on the eastern coast of New-Holland, which extends in an uninterrupted course the distance of three hundred and fifty miles. This together with several islands of the same, form a continuous line of one thousand miles or more in length, varying from twenty to sixty miles in breadth. To form a just conception of such a production, we should imagine it exposed from the foundation. It is a mountain ridge, which bears comparison with many of the larger tracts of terrestrial limestone in height; the soundings in that sea being generally from 1000 to 1500 feet deep; and with respect to extent of range, it would far exceed any limestone formation known.-Macculloch, vol. i.-337.

But though we may be astonished at the vast productions of these diminutive animals, it is their instinct which ought still more to interest and surprise us. For, when we remember that in many other instances, numbers do compensate for individual weakness, and that there are myriads of millions of these constantly at work, our astonishment rather arises from a consideration of their numbers than the amount of their labors. And here we cannot but admire the beneficence of the Creator in having