76 FKINGING- EEEFS. Ch. III. 



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

 and front the snores of continents. In the charts 

 of the eastern coast of Africa, by Captain Owen, 

 many extensive fringing-reefs are laid down ; — thus, 

 for a space of nearly 40 miles, from lat. 1° o to 

 1° 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 high, and as the 

 bottom shoals vary gradually, (the depth being only 

 from 8 to 14 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 de- 

 scribed as formed of projecting points ; and within it 

 there is a channel from six to twelve feet deep, 

 with patches of living coral. At Mukdeesha (lat. 

 2° 1/ N.) 'the port is formed,' it is said, 1 ; by a long 

 reef extending eastward four or five miles, within 

 which there is a narrow channel, with ten to twelve 

 feet 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 4 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 



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

 are likewise taken. 



