The geographical reader will remember that to the eastward of the great, and to ourselves nearly unknown, island of Madagascar, there lies a small group of islands of volcanic origin, which, though not exactly contiguous among themselves, are yet nearer to each other than to the greater island just named, and which is interposed between them and the coast of Southern Africa. They are named Rodriguez, Bourbon, and Mauritius, or the Isle of France. There is proof that not fewer than four distinct species of large-bodied, short-winged birds, of the Dodo type, were their inhabitants in comparatively recent times, and have now become utterly extinct. We say utterly, because neither proof nor vestige of their existence elsewhere has been at any time afforded; and the comparatively small extent, and now peopled state of the islands in question, (where they are no longer known,) make the continuous and unobserved existence of these birds, so conspicuous in size and slow of foot, impossible. Now, it is this recent and total extinction which renders the subject one of more than ordinary interest. Death is an admitted law of nature, in respect to the _individuals_ of all species. Geology, "dragging at each remove a lengthened chain" has shown how, at different and distant eras, innumerable tribes have perished and been supplanted, or at least replaced, by other groups of species, entire races, better fitted for the great climatic and other physical changes, which our earth's surface has undergone from time to time. How these changes were brought about, many, with more or less success, (generally less,) have tried to say. Organic remains--that is, the fossilised remnants of ancient species--sometimes indicate a long continuance of existence, generation after generation living in tranquillity, and finally sinking in a quiet grave; while other examples show a sudden and violent death, in tortuous and excited action, as if they had been almost instantaneously overwhelmed and destroyed by some great catastrophe.