130 CORALS AND CORAL ISLANDS. 



the boldness of the shores and depth of waters, the reef is 

 wanting. The barrier reef at one point. has a passage through 

 it, which is an opening to a harbor ; and many such harbors 

 exist about coral-erirt islands. 



HIGH ISLAND WITH BARRIER AND FRINGING REEFS. 



While some islands have only narrow fringing reefs, others 

 are almost or quite surrounded by the distant barrier, which 

 stands off like an artificial mole to protect the land from an 

 encroaching ocean. The barrier is occasionally ten or fifteen 

 miles from the land, and encloses not only one, but at times 

 several, high islands. From reefs of this large size, there are 

 all possible variations down to the simple fringing platform. 



The inner channel is sometimes barely deep enough at low 

 tide for canoes, or for long distances may be wanting entirely. 

 Then again, it is a narrow intricate passage, obstructed by 

 knolls or patches of coral, rendering the navigation dangerous. 

 Again, it is for miles in length an open sea, in which ships 

 find room to beat against a head wind with a depth of ten, 

 twenty, or even thirty fathoms. Yet hidden reefs make caution 

 necessary. Patches of growing corals, from a few square feet 

 to many square miles in extent, are met with over the broad 

 area enclosed by these distant barriers. 



These varieties of form and position are well exemplified 

 in a single group of islands — the Feejees ; and the reader is 

 referred to the chart of this Archipelago at the close of this 

 volume. 



