NOETH MALE. 43 



increased by sand being heaped up in the direction of the prevailing 

 winds or currents, forming horns eventually uniting and enclosing a part 

 of the greater inner lagoon. On the face of the banks, corals obtained a 

 foothold and consolidated the rims of the faros. Their mode of formation 

 can best be explained when tracing the changes undergone by the rings. 



In thirty fathoms at our anchorage off Male Island the bottom was 

 covered with fragments of broken coral coated with Nullipores, or was quite 

 hard, having been swept comparatively clean by the strong current rushing 

 in and out of North Male through the southeast channel. 



At our anchorage off the west face of Difuri about three-quarters of a 

 mile from the rim of the faro, we found coarse coral sand in twenty-one 

 fathoms of water ; a haul of the dredge made in about twenty-seven fathoms 

 nearly in the centre of North Male brought up coral sand mixed with more 

 or less sticky ooze and broken shells. In all cases we found quite a dif- 

 ferent bottom from that which characterizes the bottom of a Pacific lagoon. 



The greatest depth of North Male is thirty-seven fathoms. The majority 

 of the soundings indicated vary from twenty-five to thirty-one fathoms. 



As a type of an inner island, we examined a small well-wooded island 

 (PI. 9, fig. 2) which rises in the middle of the southeast passage into North 

 Male with nearly thirty fathoms on either side of it. The island is elliptical, 

 and is placed on the northwestern horn of an elliptical flat which stretches 

 out in a southeasterly direction. The fiat slopes very gently to the sea, is 

 edged on the outer rim by a sink forming a shallow ditch of varying width, 

 flanked by coral boulders or masses of beach rock extending as an irregular 

 wall along the greater part of the outer edge of the reef flat. The greatest 

 width of the reef flat is from two hundred and fifty to three hundred feet. 

 It diminishes gradually in width to the northwestern corner, where the 

 island is steep to. Corals grow in great abundance at a depth of from 

 five to three fathoms upon the steep slopes of the reef flat; they grow 

 with less profusion to six or seven fathoms, where they are separated by 

 wide lanes and patches of sand which eventually cover the whole bot- 

 tom at a depth of from eight to nine fathoms. From the three-fathom 

 line, they also diminish in number towards the surface and spread over 

 the edge of the flat, which is partly bare at low water; they extend but 



