chap, x.] THE PAL.EARCTIC REGION. 201 



In addition to the territories now indicated as forming part 

 of the Mediterranean sub-region, we must add the group of 

 Canary Islands off the west coast of Africa which seem to be 

 an extension of the Atlas mountains, and the oceanic groups of 

 Madeira and the Azores ; the latter about 1,000 miles from the 

 continent of Europe, yet still unmistakably allied to it both in 

 their vegetable and animal productions. The peculiarities of the 

 faunas of these islands will be subsequently referred to. 



It seems at first sight very extraordinary, that so large and 

 wide a sea as the Mediterranean should not separate distinct 

 faunas, and this is the more remarkable when we find how very 

 deep the Mediterranean is, and therefore how ancient we may 

 well suppose it to be. Its eastern portion reaches a depth of 

 2,100 fathoms or 12,600 feet, while its western basin is about 

 1,600 fathoms or 9,600 feet in greatest depth, and a considerable 

 area of both basins is more than 1,000 fathoms deep. But a 

 further examination shows, that a comparatively shallow sea or 

 submerged bank incloses Malta and Sicily, and that on the 

 opposite coast a similar bank stretches out from the coast of 

 Tripoli leaving a narrow channel the greatest depth of which is 

 240 fathoms. Here therefore is a broad plateau, which an 

 elevation of about 1,500 feet would convert into a wide extent 

 of land connecting Italy with Africa ; while the same elevation 

 would also connect Morocco with Spain, leaving two extensive 

 lakes to represent what is now the Mediterranean Sea, and afford- 

 ing free communication for land animals between Europe and 

 North Africa. That such a state of things existed at a com- 

 paratively recent period, is almost certain ; not only because a 

 considerable number of identical species of mammalia inhabit the 

 opposite shores of the Mediterranean, but also because numerous 

 remains of three species of elephants have been found in caves 

 in Malta, — now a small rocky island in which it would be im- 

 possible for such animals to live even if they could reach it. 

 Eemains of hippopotami are also found at Gibraltar, and many 

 other ^.nimals of African types in Greece ; all indicating means 

 of communication between South Europe and North Africa which 

 no longer exist. (See Chapter VI. pp. 113 — 115.) 



Vol. L— 15 



