1898.] Funafuti, Rotuma and Fiji. 435 



platform, the bottom is generally covered by a sand which is 

 similar in all respects to the sand described by Professor Sollas. 

 It does not extend far into the lagoon off these reefs, and the 

 arming of the lead usually comes up clean, or only contains a few 

 of the segments of different species of Halimeda. To leeward of 

 all the windward islands, sand is found most abundantly, but only 

 by the main island does it extend more than a couple of hundred 

 yards into the lagoon where, however, it runs out about 1^ miles 

 in a bank with about 17 fathoms of water, the breadth of which a 

 mile out from the shore is only about 250 yards. It seems to me 

 to be deposited by an eddy meeting here, caused by the rising and 

 rushing of the tide over the reefs to the north and south of this 

 island. These currents sweep up and down along the coast, the 

 lagoon reefs surrounding which are notably free from mud and 

 sand. The sandy part of the island by the village, I think, has 

 been formed by the deposition and washing up of sand by this 

 means, and, if any reliance can be placed on the reports of the 

 natives, the lagoon is here evidently silting up. 



In dredging, I took bearings across the lagoon from the village 

 in three directions, besides trying off certain islands and in 

 particular localities ; I also took a series of soundings at the same 

 time to find out the nature of the bottom over which I was passing. 

 The dredges were made by the Zoological Station at Naples, the 

 one with a net and the other a canvas bag. The result showed 

 that the bottom generally must be a flat surface of hard rock, as 

 repeatedly nothing but a few segments of Halimeda were brought 

 up, and the dredges, while they could be felt on the rope working 

 along the bottom, met with no hindrances. Near the shoals 

 masses of dead coral were occasionally obtained, but living corals 

 never. I cannot agree with Professor Sollas that there is any 

 evidence that the lagoon of the atoll is filling up, except in the 

 one position opposite the village. Although I dredged over a 

 great part of the surface, I found no traces of coral growth on the 

 bottom and no shoals, with a few fathoms of water which might 

 be supposed to be coming up to the surface, and I can confidently 

 assert that there are no considerable banks of sand in the lagoon 

 other than the one already referred to. Undoubtedly there should 

 be in some parts a considerable deposition of the skeletons of such 

 an alga as Halimeda, but of such I found no traces. Either it 

 must be consolidated with the bottom, or it must be washed out of 

 the lagoon, or it must be dissolved. I have seen no evidence of 

 such a consolidation as this taking place anywhere in the islands 

 of the Central Pacific, and I believe it does not occur ; if it is 

 possible for it to take place at all, the other forces must act before 

 it has had time to consolidate. 



There is no doubt that many of the islands on the rim of the 



