a tract of dry land encompassed with water; in which sense it stands contradistinguished from Continent, or Terra Firma.

Several naturalists are of opinion, that the islands were formed at the deluge; others think, that there have been new islands formed by the calling up of vast heaps of clay, sand, mud, &c.; others think they have been separated from the continent by violent storms, inundations, and earthquakes. These last have observed, that the East Indies, which abound in islands more than any other part of the world, are likewise, more annoyed with earthquakes, tempests, lightnings, volcanoes, &c. than any other part. Others again conclude, that islands are as ancient as the world, and that there were some at the beginning; and among other arguments, support their opinion from Gen. x. 5, and other passages of Scripture.

Varenius thinks that there have been islands produced each of these ways. St Helena, Alcetion, and other steep rocky islands, he supposes to have become so by the sea's overflowing their neighbouring campaigns; but by the heaping up huge quantities of sand, and other terrestrial matter, he thinks the islands of Zealand, Japan, &c. were formed. Sumatra and Ceylon, and most of the East India islands, he thinks, were rent off from the main land; and concludes, that the islands of the Archipelago were formed in the same way, imagining it probable that Deucalion's flood might contribute towards it. The ancients had a notion that Delos, and a few other islands, rose from the bottom of the sea; which, how fabulous soever it may appear, agrees with later observations. Seneca takes notice, that the island Thera rose thus out of the Aegean sea in his time, of which the mariners were eye witnesses.

It is indeed very probable, that many islands have existed not only from the deluge, but from the creation of the world; and we have undoubted proofs of the formation of islands in all the different ways above-mentioned. Another way, however, in which islands are frequently formed in the South sea, is by the coraline infects. On this subject there is a curious dissertation by Alexander Dalrymple, Esq. in the Philosophical Transactions for the year 1768, to which we refer the reader. See also Geography Index.