416 J. STANLEY GARDINER. 



sights, and the positions of fresh land must only be taken in our chart as comparatively 

 correct. 



With regard to the islands themselves they do not differ in structure from those in any 

 other part of the group. All lie on the rim reefs, and the rule is that whatever part of 

 each island falls within about 250 yards, or a little less, of the reef edge is of raised coral 

 rock, and that the remainder is of sand. The greatest height of the rock was found in Hera, 

 i.e. 6 feet above the high-tide limit, or about 10 feet above the reef-flat. Rain water de- 

 nudation has probably been greater in this atoll than in any other, so that there is possibly 

 but little difference between the elevation here and in the rest of the group. The sandy 

 areas of the islands only attain a general height of about 3 feet above the high-tide limit. 

 The sand itself shows that they largely owe their origin to the elevation of sand-flats behind 

 the original enclosing reefs. The surface of the ground, however, has generally been further 

 raised by blown sand, so that the level of the original flats can only be traced in pools, 

 pits and wells. 



The seaward sides of the islands show less washing away than in any other atoll. The 

 reef-flat is generally well characterised and relatively broad, merging into a rough or boulder- 

 strewn zone at the base of the beach. The force of the waves is broken before they reach 

 the latter, .so that it commonly presents a much smoother appearance than usual, the coral 

 rocks and masses being bedded in sand. In places the latter has become indurated with 

 carbonate of lime, so that there is a broad line of rock at the base of the beach from the 

 half to the low-tide limit. Pinnacles and large masses of the coral rock are not common on 

 the beach, and the appearance decidedly points to the land being at the present time almost 

 stationary, so far as loss is concerned. 



It may be here observed that the elevated coral rock of Addu atoll resembles that found 

 at Minikoi and elsewhere, but has always a greater percentage of sand. The corals in it 

 show a more open texture, a more luxuriant growth, and hence the whole rock, being more 

 brittle and open, wears away more evenly than elsewhere. 



The outer reef of the atoll is noticeable for its marked edge, less Assured and more 

 defined than usual, but the whole covered with growing organisms. The slope off it is rela- 

 tively smooth and very densely crowded with growing coral. From its appearance there can 

 be no doubt that it is growing upwards and outwards. Yet on the east side the steep seemed 

 to commence at about 160 yards from the edge of the reef, hence considerably nearer than 

 off the oceanic sides of some of the other atolls of the Maldives. It was observed, though, 

 that the outer slope to the commencement of the steep broadens at every point, showing 

 growth especially in such positions. So far as change has taken place in the contour of the 

 atoll since Moresby's survey, there is no evidence, but the chief points to seaward are all 

 more emphasised and prominent at the present day than shown in his chart. To the south 

 of Huludu there is a shallow bay rather than a point, and Midu point seems very distinctly 

 to have grown out to seaward. The growth also of Wiringili reef to the south and east is 

 seen in distinct points. 



Hera, etc. The chart in this position shows six small islands immediately oflF the N.W. 

 point of Midu, whereas we found two small islets close to the point, separated by a gap about 

 400 yards broad from a clump of five islets further to the W., of which Hera is the largest. 

 These five form a line on the inner part of the reef-flat or boulder zone, which is clearly 



