REPORT ON I\rATERIALS FROM THE B0RIN14S AT FUNAFUTI ATOLL. :]U) 



very largely composed of tbramiinfera aud HaliiiK'da-jomtH, whilst corals are only 

 sparsely present. Ci/clocli/peu^- hixs only been met A\itli in the Main Boring. According 

 to Mr. Chapman'^'' it has nut been fonnd in the lagoon dredgings ; in those from the 

 onter slopes of the reef it occnrs from 30-200 fathoms. 



(7b) Notes on thf, (Jokals from tiik Funafuti BoKiNos.t 



Reference has already b>een inade to the ilnportant changes which the corals in the 

 borings have nndergone in the conrse of fossilisation, and to the difficulties arising there- 

 from in determining their original characters and affinities. Throughout the three 

 shallower borings, and in the Main Boring to a depth of about 180 feet from the surface, 

 the corals in the cores retain their walls and other structures, as a rule, in fair 

 preservation, although many of their characters are nnich obscured by the way in which 

 their interstices have been infilled with a secondary deposit of fibro-crystalline carbonate 

 of lime, which often closely simulates the natural structures of the corals. At greater 

 depths in the boring, the corals for the most part have been dissolved, leaving casts 

 of fine calcareous sediment or of crystalline materials, Avhich i]i some cases remain 

 empty, whilst in others they are refilled with crystalline calcite or dolomite. Very 

 frequently also the coral has been entirely dissolved away, leaving a cavity bounded 

 by consolidated calcareous sediment, which bears the imprint of the exterior surface 

 of the coral, and within the hollow there is an interlacing network of delicate fibrous 

 threads and nodes, Avhich are the tubes made by boring sponges and other organisms, 

 now solidly infilled with sediment. The dissolution of the corals in the borings could 

 obviously have taken place only after the consolidation of the calcareous inud which 

 had covered them. 



Owing to these unfavourable changes, the minute structural details, on which the 

 specific characters of recent corals depend, are usually obliterated in these fossil 

 foiins, and even the characteristic generic features of some of the closely allied 

 Astrsean corals are no longer recognisable. The determination of the genera and 

 species in well preserved recent corals is often very difficult, owing to their wide 

 range of variability, but in the case of most of the fossil Funafuti specimens complete 

 identification is well nigh hopeless. It seems highly probable, however, that they all 

 belong to known genera of reef-building corals, and most of the species appear to be 

 closely allied to, if not the same as, those already described. In only a single 

 instance has there been sufficient ground for regardnig a form as a new species. 



As shown in the accompanying list, the corals frojn the borings comprise 2 genera 

 of Hydrocorallina3, 2 of Alcyonaria, 13 of Madreporaria Aporosa, 10 of which belong 

 to the Astraeidse family, 5 of Madreporaria Fungida, and 6 of M. perforata. With 

 the single exception of Goruiopora, these genera are all present in the Main Boring, 



* 'Linneaii Soc. Journ.,' Zoology, vol. 28 (1900), pp. 21-26. 



t As previously mentioned, for the sake of convenience, Alcyonaria and Hydrocorallinie are included 

 with the Madreporaria under the general term " Corals" in this report. 



