226 Cruise of the "Alert" 



6 1 2^ south latitude, and 53 45' and 52 50^' east longitude, 

 and is about seven hundred miles distant from the nearest part of 

 the East African coast. Some of the islets and cays of which it 

 is composed, and which are included in the above enumeration, 

 are so grouped into clusters, that for all practical purposes the 

 group may be considered as consisting of nine islets, which have 

 been named African Island, Eagle Island, Darros Island, Poivre 

 Island, Des Roches Island, Etoile Island, Marie-Louise Island, Des 

 Neufs Island, and Boudeuse Island. Of these only three are 

 inhabited ; viz., Darros (including the adjoining islet " St. Joseph," 

 which is occupied by part of the same establishment of Creoles), 

 Poivre Island, and Isle des Roches ; the population consisting of 

 French Creoles and negroes imported from Seychelles, who make 

 a livelihood by cultivating cocoa-nuts, and altogether do not 

 exceed forty in number. The islets are all low and flat, are 

 formed entirely of coral and coral-sandstone, and their general 

 surface has an altitude above high water mark not exceeding 

 fifteen feet, while in the case of African Island, the lowest, it is 

 not more than seven feet. Most of them, however, are conspicuous 

 from a long distance at sea, on account of their possessing clumps 

 and groves of casuarina trees, which tower to heights ranging from 

 eighty to one hundred and eleven feet above the soil, as ascertained 

 by trigonometrical measurement. The casuarinas at Darros Island, 

 which were eighty feet in height, had been planted nineteen years 

 prior to the time of our visit by a Frenchman named Hoyaeux, 

 whom we subsequently met at Providence Island. 



All the islets above-mentioned possess " fringing reefs," but are 

 distinguished from the coral islets of the South Pacific, and of the 

 other parts of the Indian Ocean, by the entire absence of " barrier 

 reefs." The soundings which we made over the Amirante bank 

 showed a general uniformity in the contour of its surface ; whilst 

 at the same time there was abundant evidence that the central 

 portions were more depressed than the margins. Soundings in 

 the latter situation gave a depth ranging from ten to fourteen 



