REPORT ON MATERIALS FROM THE BORINGS AT FUNAFUTI ATOLL. 187 



To facilitate examination, the longer cylindrical cores of the Main Boring were cut 

 transversely into pieces of 5 or 6 inches (125-150 millims.) each in length, and these 

 and all the other cores from the different horings, hoth cylindrical and nodular, were 

 slit longitudinally by a lapidary's wheel armed wii-h diamond dust. As the result of 

 this process the median face of each half of the core (where the rock was sufficiently 

 hard), was left nearly as smooth and even as if it had been polished, so that its 

 strucUire -could be readily distinguished with a lens. More than 400 microscopic 

 sections were also prepared from longitudinal and transverse slices of the solid cores 

 wherever it seemed desirable to study in detail the structure of the rock and of the 

 organisms in it, and thin sections of the incoherent fragmental materials were likewise 

 skilfull}'- prepared by Mr. F. Chapman. The slow and tedious work of slitting 

 over 400 feet of the rock-cores, a,nd the preparation of the microscopic slides, 

 were efficiently carried out at the Geological Laboratory under the direction of 

 Professor Judd. 



A partial study of the cores from the upper part of the Main Boring had already 

 been made by Professor T. W. Edgeworth David, F.R.S., and with his approval I 

 have availed myself of his notes and followed generally the lines of investigation 

 which he had begun. 



For the determination of the Foraminifera shown in the microscopic sections and 

 in the loose materials from the borings, I have relied upon the authority of 

 Mr. F. Chapman.* His study of the recent forms of the group dredged from the outer 

 slopes of the reef and from the lagoon at Funafuti, render his determinations of the 

 forms embedded in the cores especially valuable. I am myself responsible for noting 

 the common and familiar kinds present in nearly all the cores of the various borings. 



I also wish to acknowledge my indebtedness to Mr. J. Stanley Gaedinee, for the 

 loan of recent corals which he had collected at Funafuti, and for examining some of 

 the fossil forms from the borings. 



The measurements of the borings and cores taken on the spot in English feet and 

 inches, have been retained in the report without alteration, but for measuring the 

 separate pieces of core it has been more convenient to adopt the metric system. 



(2). — General Features of the Main Boring. 



The Main Boring on the Funafuti Atoll was commenced in 1897, under the direction 

 of Professor T. W. Edge worth David, and carried down in that year to the depth 

 of 698 feet. In the following year the boring was resumed under the charge of 

 Mr. A. E. Finckh, and continued to the depth of 1114-1- feet from the surface. 

 The diameter of the cores brought up in the core barrel was as follows : From the 

 surface to 68 feet, about 4 inches (103 millims.); from 68-210 feet about 3|- inches 



* 'Linn. Soc. Journ.,' Zoology, vol. 28 (1900-3), pp. 1-27, 161-210, Plates 1-4, 19, 20. 



2 B 2 



