GEOGRAPHIC DISTRIBUTION OF ANIMALS: OCEANIC ISLANDS 

 Nature of Oceanic Islands 



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Typical oceanic islands are not located on continental shelves. Most of 

 them are far from any continent, with hundreds or thousands of miles of 

 deep ocean in between. Most of them are the summits of mountain peaks 

 rising from the ocean floor through thousands of feet of water and thence 

 on up into the air. Most of them are volcanic, many still actively so. 





FIG. 13.1. Birth of a volcanic island. One of a group of new volcanic islands pushing 

 its v/ay up from the sea floor 200 miles south of Tokyo, Japan. Seen from the USS Nor- 

 ton Sound (AV-11), Lot. 31-57 N., Long. 140-01 E. (Official Department of Defense 

 photo.) 



A dramatic view of the birth of such an island is shown in Fig. 13.1. 

 Here the summit of a submerged volcanic mountain is caught in the act of 

 breaking the surface of the Pacific, like a giant erupting tooth. From such 

 beginnings oceanic islands are built. Perhaps the one shown in the picture 

 may not develop into a large island; it may remain a small "bird rock," so 

 called because the principal inhabitants are sea birds which use the small 

 island for nesting. On the other hand, it may continue to thrust itself up- 



