GENERAL REPORT ON THE MATERIALS SENT FROM FUNAFUTI. 179 



the borinu's in the island of Funafuti. In these loose materials there occurred more 

 lirmly compacted masses of coral rock, which were penetrated with great difficulty, 

 under the unftivourable conditions in which the work of boring was carried on. At a 

 depth of 177 feet {76 feet below the floor of the lagoon) a solid mass 5 feet thick was 

 bored through, at 217 feet another solid mass 18 inches thick was penetrated, and 

 from the material broken up and disintegrated by the boring tools, fragments, angular 

 and subangular, up to the size of a walnut were brought up. The boring was stopped 

 at a depth of 245 feet by solid coral rock which could not be penetrated with the 

 appliances available. 



In the second boring, which was made at a distance of only 90 feet north of the first 

 one, a similar section was obtained. Under the Halimeda sand, which was from 60 

 to 70 feet thick, coral rock was found, which broke up under the boring tools, but 

 there was a more solid mass 3 feet thick (with some softer partings) at a depth of 

 92 feet from the bottom of the water in the lagoon. This second boring was carried 

 to a depth of 2 1 4 feet in the easily disintegrated coral rock before hard impenetrable 

 masses were met with. 



The numerous frao-ments of corals obtained in these lao-oon borin&s beneath the 

 Halimeda sand, have been very carefully studied by Dr. Hinde and Mr. Bernaed, 

 while the foraminifera have been determined by Mr. Chapman. Of course, made as 

 the borings were (see Mr. Halligan's report p. 161), no solid cores like those 

 obtained by the aid of the diamond drill could be secured, but the numerous fair-sized 

 angular fragments evidently broken off by the edge of the tube and by the boring 

 chisels, supplied sufficient evidence as to the nature of the solid rock passed through. 



Specimens of all the reef-forming and other genera of corals which occur in the 

 main boring were obtained from the boring in the lagoon. They include such forms 

 as Heliopora, Madreporaria [M. contecta being present), Montipora, . Porites, 

 Pocillopora., Goniopora, AstrcBopora, Lob ophy turn, Cceloria, Fungia, CypJiastrcea and 

 other Astrsean corals, Seriatopora, &c. The most numerous foraminifera are those 

 belonging to the genera Amphistegina and Heterostegina, but Polytrenia planum 

 and other encrusting forms are common, while all the genera which occur abundantly in 

 the main boring are found to be represented in the rocks passed through in the lower 

 part of the lagoon boring. Here, too, were found the usual moUusca, and other 

 organisms of the reef, with alcyonarian and tunicate spicules ; Lithothamnion and 

 Halimeda are also present in considerable abundance. 



This evidence indicates that at a depth of more than 40 fathoms in the lagoon o± 

 Funafuti, we have a rock built up of the common reef-forming corals, with the other 

 organisms usually associated with them. This mass of coral rock would appear to lie 

 generally at depths of from 36 to 40 fathoms from the surface of the water in the 

 lagoon, but in places to form bosses that constitute shoals only covered at high tide. 

 In these shallower portions of the lagoon the corals are found to be still alive and 

 growing, 



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