122 THE CORAL REEFS OF THE MALDIVES. 



Kolumadulu. 



Plates 1, 5 ; 8 b, Jiffs. 17, 18 ; 8 c, fig. 20 ; 66. 



Kolumadulu (PI. 5) is nearly circular; its greatest diameter from east to 

 west is twenty-nine miles; the north and south dimensions are somewhat less. 

 Its sea faces are flanked by narrow reef fiats, with the exception of the wider 

 flat bounding the southern face from Vaimandu to Hirilandu; on this flat are 

 also some of the larger islands of Kolumadulu. A few islands are scattered 

 on the reef flats of the northeast face, and a long line of islands and islets ex- 

 tends in a southerly direction on the southeast face from Fahala, an island 

 nearly four miles in length, and one of the largest in the Maldives. 



Kolumadulu is deeper than the northern groups ; it attains a depth of 

 forty-five fathoms in the central area ; the greater number of the soundings 

 are near forty fathoms.^ The interior of Kolumadulu is dotted with small 

 banks; they are more numerous in the southern half of the western part 

 of the atoll. The only islands in the atoll are near the western face opposite 

 the pass to the south of Kandudu and on a large faro to the eastward of 

 Hirilandu. 



The islands of the northern part of the east face of Kolumadulu present 

 no features of special interest ; they are fairly covered with low vegetation 

 and edged by steep corsil sand beaches. Fahala, one of the larger islands 

 of the Maldives, over three and a half miles in length, is covered with fine 

 vegetation ; south of it, on the greater part of the islands of the east face 

 of Kolumadulu, the vegetation consists almost entirely of low reef vege- 

 tation similar to the scanty flora of many of the Pacific atolls. 



South of Fahala^ a number of islands liave been thrown up diagonally 

 across the reef flat ; the points and beaches of their outer faces are covered 



' Mr. Gardiner found no changes in the depth of the lagoon of Kolumadulu, and says that in but 

 few of the islands of the outer reef flats did he detect any changes with the exception of a " slight 

 washing away of their seaward faces." * He also speaks of important changes in two of the passages he 

 examined; they are not indicated in his Figure 106, p. 407. 



Mr. Cooper states that a few of the shoals represented on the charts as reaching the surface only 

 existed as mounds well below the low-tide level.f 



^ The most marked changes which have taken place in the land rim of Kolumadulu, Mr. Gardiner 

 notes at Fahala ; he has observed that the island has become joined to the small island marked on the 

 chart to the north of it; in its place is now found a velu, the washing away of its southern end. (Loc- 

 cit., p. 407.) 



* Loc. cit., p. 407. t Loc. cit., p. 408. 



i 



