1899] FUNAFUTI: THE STUDY OF A CORAL ATOLL 37 



material so loosely aggregated should be able to sustain itself in slopes 

 of as much as 80°, such as characterise the flanks of Funafuti. It is im- 

 portant, however, to observe that none of the borings yet made have been 

 sunk through the true growing substance of the atoll. They have com- 

 menced on the lagoon side of the true coral reef, and the deeper they have 

 descended the more remote they have become from the ocean flanks. The 

 possibility exists, and should not be overlooked, that a great part of the 

 material passed through in the bore-holes represents deposits of the 

 lagoon and of the fragmentary debris driven towards it by the breakers. 



It will be observed that Professor David's bore -hole does not 

 traverse the whole thickness of the table-mountain ; judging from the 

 soundings, it would have to descend 20 or 30 fathoms deeper to do 

 this, and it would seem likely that the material obtained from this last 

 20 or 30 fathoms might surpass in interest all the rest. Our friends 

 in Sydney fully appreciate this, and are so bent on probing this question 

 to the utmost, that they have already despatched, at great pecuniary 

 risk, an expedition to make a third attempt on Funafuti, and this time 

 to carry the bore-hole right through the table-mountain. 



The boring party is at this moment at work on the island, and 

 before many weeks have elapsed we may expect to receive tidings of 

 their success. A great stride will then have been taken towards a final 

 determination of the long-standing controversy on the origin of atolls. 1 



We eagerly await the result, which will inform us whether these 

 central oceanic islands are ancient remains of land which have plunged 

 beneath the sea and are renewing their youth, or whether they are among 

 the latest products of our planet, aspiring mountains which have scarcely 

 yet succeeded in their struggle upward to the light of day ; whether 

 they are, as has been said, " a garland laid by the hand of Xature on 

 the tomb of a sunken island," or whether they may not be a wreath of 

 victory crowning a youthful summit on its first conquest of the main. 



1 The critical point has been passed. (See Nat. Sci. xiii. p. 362.) According to the 

 news from Funafuti (Sept. 6) the boring attained a depth of 987 feet, or 147 feet below the 

 base of the steepest cliff. The material passed through was coral limestone. It is of 

 interest to observe that, soon after passing the bottom of Professor David's borediole, loose 

 unconsolidated deposits ceased to be encountered, and the drill passed with comparative 

 facility through a hard limestone containing numerous well-preserved corals. A crux of 

 all theories of atolls is the lagoon. On Darwin's theory its explanation follows naturally 

 from the fundamental assumption. Sir John Murray has to supplement his hypothesis by 

 a separate explanation, and proposes to account for the lagoon by solution. In this connec- 

 tion the success which has attended an attempt of the present expedition to bore into the 

 bed of the lagoon is most welcome. The boring was made from the deck of H.M.S. 

 ' : Porpoise," commanded by Capt. Sturdee, and after passing through 101 feet of water sank 

 144 feet into the deposits of the floor. The first 80 feet were found to consist of the calcareous 

 alga Halimeda mixed with shells; the remaining 64 feet of the same material, mingled 

 with coral gravel. This alga is universally distributed over the floor of the lagoon, as 

 proved by an examination of the material obtained by Capt. Field in sounding, and since 



it contains a certain percentage of magnesium carbonate we are Led to ex] I that the 



formation of dolomite will be found to stand in some connection with the transformation of 

 lagoon deposits. 



169 Woodstock Road, Oxford. 



