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334 CHAP. XVII. On the Formation of Coral Islands. 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 and necessary branch of the present inquiries; and it is the more indispensable to examine it, because it has hitherto been unaccountably neglected by geological writers- In the case of other submarine animal formations, the results are limited to the germs of future and far distant continents, as the works are without apparent design. But the operations of the coral animals are very different. By their own efforts, assisted by some incidental causes, they build their works above the level of the ocean during their own lives; thus forming rocks and islands, without the necessity of those actions which have raised all the other submarine strata from below. In this manner is the habitable surface of the earth extended, and new regions arise in the ocean. The silent and unnoticed operations of the minutest animals of Creation, are daily preparing the foundations of land, beneath it, destined to extend the dominion of man over a far wider range. But the volcanic agencies which form the subject of a former chapter, are frequently found to succeed to these; thus accelerating their results, elevating high above the water that which would otherwise have for ever remained but little raised beyond its