412 J. STANLEY GARDINER. 



40 yards apart, and always have sloping — not overhanging— sides. At the edge, where there is a small 

 precipice of 2 fathoms, only nullipores were found. The reef outside slopes gradually, the bottom 

 for about GO yards being quite visible and covered with living corals. 



The enormous quantity of Udiopora is very remarkable, quite a large area of the sand-flat 

 being covered by it, and without parallel on any reef that I have seen, in the Maldives or elsewhere'. 

 Doubtless it is due to the denser skeletons of these Alcyonarians resisting the decay brought about 

 by organisms better than the Madreporaria, the dead corals of which were all much rotted on the 

 same area. The variation of the character of the reef edge compared with more northern atolls 

 is noticeable, particularly in the fissures having sloping, not overhanging, edges. 



The seaward reef merges round the S. end of Kondai into the lagoon reef, being about 120 yards 

 distant at the S. point. The lagoon reef has the characters previously described ofl' Wiringili, but 

 its edge is very irregular, and much of the bottom off the same is covered with sand. 



Hanlus, Labadu and Lillis islands are all sandy and covered with low bushes. The only 

 change was seen in an outgrowth of the reef of Labadu to the W.S.W. The islands of Diaddu 

 reef are likewise all sandy with spits along their reef. Diaddu island and reef both show an out- 

 growth towards the lagoon. Mawaru and the island to its S. are joined, as indeed nearly are 

 the next pair on its reef. The reef of the sandy Noorbhai island has extended out to the S. 

 and there has appeared a small shoal to the E. The reef from Huluwarolu to Gadu has a double 

 set of islands, the eastern formed partially of rock, but the western composed entirely of sand. The 

 latter are extending out towards one another, and one has already become fused up to Huluwarolu 

 The two islands next N. of Gadu have very extensive formations of beach sandstone on their sea- 

 ward sides. 



The seaward or E. reef of Gadu is similar to that off Kondai, but there is no Heliopora 

 zone and less dead coral; the boulder zone also is more conspicuous. Ihe land behind sliows a little 

 erosion, and there are lines of beach rock on the sand-flat. The island is only built up of stone to 

 the S., and this part consists principally of pebbles, which have become consolidated togetlier ; inland 

 maj' be traced the lines of three former beaches, showing how the land has been extending outwards 

 on its reef. The beach against the jiassage almost runs on to the boulder zone, which has towards 

 its inner part a definite line of elevated coral masses, now much undermined. The inner flat in 

 this part, wherever it exists, is peculiar in that it consists of bare rock with no sand. The reef 

 also has right round its edge a crest absolutely similar to that at Rotuma^, an equal development 

 not being found by us elsewhere in the group. The boulder zone further extends right round to 

 the lagoon side, where the edge of the reef almost reaches the surface, thence falling almost perpen- 

 dicularly to the floor of the lagoon. 



It is difficult off Gadu to trace the line of the original elevation, but the land probably never 

 extended out to the E. as far as the present boulder zone. In this position there is a line of 

 coral pinnacles about 90 yards behind the reef edge, 40 — 50 yards within the boulder zone. This 

 continues as far as the eye can see to the N., and, if it be taken even as the inner end of the 

 original raised reef, would show an outward growth for the present reef of at the least 70 yards 

 since the elevation took place. 



The waves during our visit to Gadu were occasionally breaking right along the whole distance 

 to Gan, the passage seeming much narrower than shown on the chart. Gan itself is quite similar 

 to Gadu ; its reef has grown out to the N.E., and there is a stone heap in this position on the 

 boulder zone. The island shows marked loss on the S.W. side, but N.W. the lagoon-reef is only 



' It compares only with the raised Heliopora reef, de- p. 422 (1898). 

 scribed at Funafuti by Professor SoUas in Nature, vol. Lv. - " The Coral Reefs of Funafuti, Rotuma, etc.," Proc. 



p. 376, and referred to by me in Pcoc. Cumft. P/i/;. Soi-. vol. IX. Cumb. Phil. Soc. vol. ix. p. 442 (1898). 



