THE GREAT BARRIER REEF 321 



that the outer strips of flats, now worn to below the level 

 of the sea, were at no very distant time (geologically) 

 covered by a reef which was elevated from ten to twelve 

 feet above the highest level at which corals are now 

 growing. Gradually this elevated reef was eaten away 

 by the action of the sea, and this accounts for the small 

 fragments of dead coral which are scattered over the 

 outer reef flats. On the inner reef flats, where the pro- 

 cess has not gone on quite so long, he found the ele- 

 vated reef eaten into " negro heads ; " while yet nearer 

 the mainland there are still portions of the reef that 

 have not been so eaten. Thus the upper part of the 

 present reef may be said to form a crust over the dead 

 and denuded elevated reef, which forms the core of the 

 reef. 



The same erosion and denudation that formed the 

 great submarine plateau of Queensland, undoubtedly 

 has separated North Queensland from New Guinea, and 

 left the shallow continental shelf stretching between 

 them. Finally, he concludes that if the Cretaceous sub- 

 sidence and subsequent elevation of the beds then formed 

 in Australia could be traced sufficiently far to the east- 

 ward, the same erosion and denudation of these beds 

 would go far to explain the existence of the banks, 

 islands, and archipelagoes of the Southern Pacific. 



