128 CORALS AND CORAL LSLANDS. 



silt they were bearing off, and thus secure its addition to the land. 

 They prevent, therefore, the waste which is constantly going 

 on about islands without such barriers ; for the ocean not only 

 encroaches upon the unprotected shores of small islands, but 

 carries off much of whatever the streams empty into it. The 

 delta of Rewa, on Viti Lebu, resultmg from the detritus accumu- 

 lations of a large river, covers nearly sixty square miles. This 

 is an extreme case in the Pacific, as few islands are so large, 

 and consequendy rivers of such magnitude are not common. 

 But there is rarely a coral-girt island which has not at least 

 some narrow plains from this source; and upon them the vil- 

 lao-esof the natives are usually situated. Around Tahiti these 

 plains are from half a mile to two or three miles in width, and 

 the cocoa-nut and bread-fruit groves are mostly confined to 

 them. 



The reefs also provide extensive fishing-grounds for the 

 natives, and afford abundant fish, their main reliance in the way 

 of animal food. They also supply large interior waters for 

 practice in navigation and for safe communication between dis- 

 tant settlements. And the effect is evident in the spirit of 

 maritime enterprise which characterises the islanders ; for 

 these circumstances have favoured the construction of large sail- 

 canoes in which they venture beyond their own land, and often 

 undertake voyages hundreds of miles m length. Communica- 

 tion between the Friendly Islanders and the Feejees has long 

 been kept up by means of these large rudely-rigged sail-canoes. 

 Instead of a rock-bound coast, harbourless and thinly 

 habitable, like St. Helena, in the tropics, and nearly all extra- 

 tropical islands, the shores of these reef-bound lands are 

 blooming to the very edge, and wide plains are spread out 

 with bread-fruit and other tropical productions. Harbours, safe 

 for scores of vessels, are also opened by the same means ; and 

 some islands number a dozen, when the unprotected shores 

 would hardly have afforded a single good anchorage. Jukes 

 remarks that the sea within the great Australian barrier is 

 " one great natural harbour ; " and this harbour is as long as 

 from the extremity of Florida to Newfoundland. 



