CORAL-REEFS. 79 



Elizabeth 1 Islands, where it is only fifty yards in width : 

 the sea round these islands is very deep. 



Fringing-reefs, like barrier-reefs, both surround islands, 

 and front the shores of continents. In the charts of the 

 eastern coast of Africa, by Capt. Owen, many extensive 

 fringing-reefs are laid down ; — thus, for a space of nearly 

 forty miles, from lat. i° 15' to i° 45' S., a reef fringes 

 the shore at an average distance of rather more than one 

 mile, and therefore at a greater distance than is usual in 

 reefs of this class ; but as the coast-land is not lofty, and as 

 the bottom shoals vary gradually (the depth being only from 

 eight to fourteen fathoms at a mile and a half outside the 

 reef), its extension thus far from the land offers no difficulty. 

 The external margin of this reef is described as formed of 

 projecting points, within which there is a space, from six to 

 twelve feet deep, with patches of living coral on it. At 

 Mukdeesha (lat. 2 1' N.) "the port is formed," it is said, 2 

 " by a long reef extending eastward, four or five miles, 

 within which there is a narrow channel, with ten to twelve 

 feet of water at low spring-tides ; " it lies at the distance of 

 a quarter of a mile from the shore. Again, in the plan of 

 Mombas (lat. 4 S.), a reef extends for thirty-six miles, at 

 the distance of from half a mile to one mile and a quarter 

 from the shore ; within it, there is a channel navigable " for 

 canoes and small craft," between six and fifteen feet deep : 

 outside the reef the depth is about 30 fathoms at the distance 

 of nearly half a mile. Part of this reef is very symmetrical, 

 and has a uniform breadth of 200 yards. 



The coast of Brazil is in many parts fringed by reefs. Of 



1 Mauti is described by Lord Byron in the voyage of H.M.S. Blonde, 

 and Elizabeth Island by Capt. Beechey. 



2 Owen's Africa, vol. i. p. 357, from which work the foregoing facts 

 are likewise taken. 



