166 



PROF. W. J. DAKIN : EXPEDITION TO THE 



The floor of the hollows referred to on the more northerly island was of 

 hard coral, with a small deposit of calcareous mud. Ulva and one or two 

 species of mollusca abound in the water and a fish (a species of Cobbler) was 

 captured in the smaller cavity. It is impossible to say whether these fish 

 could pass in after having attained the size which they measured — 7 to 8 inches. 

 They may have reached the interior at a much earlier stage and developed 

 there. In any case they must have passed at some stage through a 

 considerable length of subterranean channel, for it is very unlikely, if not 

 impossible, that human hands could have placed them where they were 

 found. 



Text-figure 10. 



We have surveyed the rim islet known as Wooded Island and a rough 

 map of the same is given (text-fig. 101 which shows the extent of the 

 remarkable lake or "velu." * Now this velu is of very considerable depth 

 (6 fathoms), and from certain points of difference between it and the smaller 

 one<s mentioned, and also from the fact that very similar " holes" exist on the 

 reef-flat in the lagoon close by, I am inclined to believe that this lagoonlet 

 or " velu " had developed before Wooded Island rose above high-tide level. 

 In any case, the original velu has been enlarged since, by erosion similar 

 to that taking place in the smallest pits, and probably guano workers have 

 shifted deposits from it where the mangrove trees are found. 



One very frequently finds mangrove trees growing in these hollows — in 

 fact they are restricted to this position on the islands of the outer rim of the 

 Easter Group. Several small thickets occur on the shores of the velu 

 of Wooded Isle, and a thicket occurs in a similar depression (which, however, 



* The term " velu " is used by Stanley Gardiner for the lagoonlets or deep pools some- 

 times found on the islets cf the Maldive atolls. I have not used the term throughout for 

 the hollows referred to above, owing to an uncertainty as to whether it would be correct to 

 apply it here. The lagoonlet on Wooded Island seems, however, to agree both in formation 

 and appearance with the " velus " of the Maldives. 



