192 THE OCEAK. | 



JSIoluccas, New Guinea, and Australia, are likewise on a sort of 

 pedestal, which sinks gradually, and upon which the zoophytes con- 

 struct here and there long barrier reefs. Thus, as the naturalist 

 Wallace has demonstrated by his researches in the Indian Archie 

 pclago, all the species of plants and animals differ completely on each 

 side of the dividing channel. The fauna and flora are Asiatic to 

 the west, while to the east they present the Australian type ; even 

 the birds, for whom a strait a few leagues in width would seem but 

 a slight obstacle, are distinctly different in each of the two groups of 

 islands. 



We must therefore see in the Australian Arcliipelagos the wreck 

 of a great continental mass, which must have divided into numerous 

 fragments at epochs more or less distant from our time. We may 

 say as much of the islands of the ^gean Sea, of those of Denmark, 

 of the Polar Archipelago, of the New World, of the maze of the 

 Magellanic Islands, and of the greater part of lands which surround 

 the shallower Avaters in the neighbourhood of the coasts. As to the 

 great islands of the Mediterranean, Cyprus, Crete, Sicily, Sardinia, 

 Corsica, and the Balearic Islands, they are also very probably the re- 

 mains of more extensive countries formerly united to those continents 

 now known as Europe, Asia, and Africa. For though these lands, 

 with the exception of Sicily, all rise from the depth of abysses, 

 having, on an average, from 500 to 1000 fathoms depth, nevertheless 

 the fossil and living species of the Mediterranean Islands do not differ 

 from those of the neighbouring continents, and it is consequently 

 there that we must seek their origin. From a geological point of 

 view, one can even say that the countries of the western basin of the 

 Mediterranean, Spain, Provence, the Italian peninsula, Tunis, Algeria, 

 and Morocco, form with the neighbouring islands a whole much more 

 precisely defined than, for example, central Europe, from the Straits 

 of Gibraltar to the shores of the Caspian. In spite of the depths 

 which separated them, the coasts lying opposite to each other, on 

 each side of the Tyrrhenian Sea, have preserved a similarity of 

 physiognomy in the flora and fauna of the land. 



The Mediterranean Islands may thus be considered either as de- 

 pendencies of the neighbouring continents, or, better still, as the 

 remains of an ancient country partially swallowed up. Still, there 

 exist in the midst of the sea insular masses in which geologists see 

 nothing else than the witnesses of continental tracts which now have 

 disappeared. Thus Madagascar, though sufficiently near to Africa, 

 seems a sort of separate world, having a flora and faijna belonging 



