124 THE CORAL REEFS OF THE MALDIVES. 



To the northeast of Timarafuri the reef flat becomes more than a mile 

 wide. The northern face of Timarafuri Pass is flanked by a wide flat edged 

 with lines of boulders, and Timarafuri Island is edged with a steep beach 

 of coarse coral shingle. The corals on the inner face of the reef flat to the 

 northeast of Timarafuri are far less flourishing than the corresponding belt 

 of corals of the more northern groups. It is perhaps what might be ex- 

 pected in such groups as Kolumadulu, the interior basin of which is com- 

 paratively shut off from the outer waters ; the outer land rims being more 

 continuous leave only few and narrow openings allowing access to the 

 oceanic currents. Thus a great amount of pelagic food is shut out from 

 the central basins of such groups as Kolumadulu, while in the central and 

 northern groups of the Maldives whei'e the outer land rim is formed of 

 atolls, separated by wide and deep passes, the currents rush in and out with 

 great rapidity. 



The larger groups forming the single line of the Maldives from Koluma- 

 dulu south to Addu, all have the same characteristics; while the smaller 

 groups on isolated parts of the Maldivian plateau, like Rasdu and Toddu to 

 the north of Ari, and Karidu, Wataru Eeef, Gaha Faro, have all the 

 characteristics of the smaller faros of Ari and of Male. Some of them, like 

 Gaha Faro, are really only larger faros separated by deeper and wider 

 channels from the adjoining groups. In fact, we may consider such great 

 plateaus as the three plateaus of Malosmadulu as one extreme, and islets 

 like Karidu and Fua Mulaku as the other extreme; while plateaus such as 

 Tiladummati and Miladummadulu, where the atolls are separated by wide 

 but shallow passages, are an intermediary stage. On the larger plateaus 

 many small atolls have been formed, while on the smaller plateaus or sum- 

 mits small faros have grown up, resembling more or less Pacific atolls, in 

 accordance with the size and shape of the underlying base. 



Nothing we have seen thus far in the Maldives indicates any marked 

 elevation ; nowhere do horses of old reef rock flanking the beaches or rising 

 upon the reef flats indicate any considerable amount of erosion. The exist- 

 ence of a few pitted and honeycombed and deeply undercut outliers of 

 modern reef rock near the outer rim of some faros, rising perhaps two or 

 three feet above the reef flats, indicates only a very slight elevation in some 



