140 THE CORAL REEFS OF THE MALDIVES. 



closed by reef flats and faros, yet form a series of wide, deep openings for 

 a distance of more than eiglit miles ; they allow a great mass of water to 

 flow in and out of the southern face of Suvadiva. Four of these passes are 

 more than thirty fathoms deep. A single such pass would almost give to 

 the enclosed waters an oceanic character; and if we add to this the mass of 

 water entering through the many passes of the western, southern, and 

 eastern faces, one can form some idea of the volume of water constantly 

 pouring in and out of Suvadiva, in addition to what is forced into it over 

 the reef flats. 



On measuring roughly the width of the passes and length of the reef flats 

 of Suvadiva, and taking from these the length occupied by the islands on 

 the reef flats, it will be found that the open spaces are large in comparison 

 to the bars formed by the islands. There are at least twenty-six miles of 

 deep passages leading into Suvadiva. The remainder of the periphery is 

 occupied by reef flats, over which water passes freely at all stages of the 

 tide. Taking the periphery of Suvadiva to be about one hundred and thirty 

 miles, not moi-e than forty-five miles of it is occupied by islands and islets. 

 Thus on fully two thirds of the circumference of Suvadiva oceanic waters 

 pass freely into the lagoon. This readily accounts for the great purity 

 of the inner waters, the rim being a very open sieve. 



The corals growing on the slopes of the bars and banks and islands of 

 this huge enclosed basin are bathed by currents bringing an abundant supply 

 of oceanic water, though they are not washed by as strong a surf as are 

 the outer faces of the land rim of Suvadiva, especially during the period of 

 the southwest monsoon. The greater strength of that monsoon is clearly 

 indicated by the trend of the summit of the trees and bushes on the sea 

 face of the western side of Suvadiva, on the islands in the atoll, and on 

 the lagoon face of the islands of the east side. Steaming north from Gan 

 Channel through the eastern part of Suvadiva in the direction of Dandu, 

 we passed a number of small banks and islands all accurately plotted on 

 the chart ; they presented no points of special intei'est. The islands were 

 evidently formed upon banks or faros in the manner already described, some 

 of them occupying but a limited area of the bank, others a somewhat larger 

 one, and others the whole of the bank, being steep to and leaving only a 



