THE ATOLL OF MINIKOI. 37 



the island and by examining all wells aii<l native excavations. North of the village it 

 practically extends from the old raised reef to the lagoon, but southwards it gradually 

 decreases in breadth, giving place to the regular lagoon beach sand. Towards the rocky 

 area more coral fragments occur, but the junction is sharply defined, while on its lagoon 

 side it merges very gradually into the finer sand. The patch at Boni-Kodi forms a soft, 

 very friable sandstone on the surface with loose sand beneath, apparently the crowbar finally 

 fetching a hard rock. The amount of consolidation elsewhere is very varied, but at the 

 mean high-tide level it commonly forms a loose sandstone, increasing gradually in hardness 

 to the low-ti<le limit, below which soft sand succeeds and water is obtained, varying in 

 sweetness with the distance from the sea. 



Reef -flats tvithout islands generally slope toivards their lagoons fur some distance, the 

 hard rock gradually giving place to a coarse sand, which has been swept across the flat by 

 the waves^. The origin of this belt of coarse sand at Minikoi must have been, I think, the 

 same, and its occurrence hence supports the view that the rocky area at one time formed part 

 of a regidar reef-flat. 



Remembering that the remainder of the sand is certainly of lagoon origin, it is of 

 interest to remark that in some of my pits in it I found alternations of harder and softer 

 sandstone, or loose sand. It was impracticable to trench across, but my pits were sufficiently 

 numerous to warrant me in the belief that there is an irregular series of lines of sand- 

 rock, more or less parallel to the lagoon shore with areas of loose sand between. I shall 

 have occasion subsequently to point out that the formation of sand-rock is characteristic of 

 beaches, which are washing away, or at rest. Hence it may perhaps be deduced that there 

 have been periods at Minikoi, %vhen sand was being actively heaped up from the la.goon, alter- 

 nating with periods of rest, or even of luashing away. 



Beach-sand-rock at the present day crops out nowhere on the lagoon shores of the island. 

 A little only is found at the west end and on the outer beach to the south. In Ko-Vari 

 bay it fringes the beach against the reef, but it is doubtful whether its constituents did 

 not rather form part of the original raised reef. The same remark perhaps applies to its 

 presence elsewhere, but the point is immaterial, as no deductions are based on its occurrence. 



The island of Wiringili is formed almost entirely of rock, much of its surface being 

 bare. It is situated at one of the most exposed parts of the atolls, for the south-west 

 gales are always those of the greatest force, and the reef outside it is narrow. The con- 

 glomerate rock forms a broad belt of ma.sses and pinnacles at the inner part of the reef, 

 many of them much undermined (fig. 10); they reach a maximum height over the reef- 

 flat of 8 feet, and loose masses add an additional 2 or 3 feet to the altitude of the land. 

 On the lagoon side of the island is a collection of small fragments of rock and sand. The 

 erosion on the seaward face is very marked, but the rest of the island is protected by 

 the conglomerate band. 



Ragandi is a bare islet of conglomerate close to the edge of the reef. It is covered 

 usually with loose boulders, thrown up by the waves, but the sea occasionally sweeps it 

 quite clean, generally carrying away at the same time a wooden beacon, which crowns its 

 summit. It is jDrobable that in a few years no trace of the land will remain. 



' Submerged reefs on the other hand are generally indeed any transition to a sandy area. 

 precipitous on all sides, and do not hence show such or 



