REPORT ON MATERIALS FROM THE ■B0RTN(4S AT FUNAFUTI ATOLL. 195 



(3). — Detailed Notes on tpie Materials from the Main Boring. 



Depth j'r 01 1 1 Surface, 0-10 feet ; Distct'iiee Bored, 10 feet ; Toted Length of Core 

 Obtained,- 2 feet 10 inches ; Numbers of Cores, l-Il. 



{^The figures betiveen curved brackets give the number of the core, and those between 

 sqiAcire brachets the number of the microscopic slide.) 



The cores obtained in this first 10 feet. from the surface are of a greyish-white, 

 hard, partly cavernous limestone, with patches of a dirty greenish tint wherever 

 Heliopora is present. They are principally of coral in cylindrical masses and 

 irregular nodular lumps. The hollows between the corals are, in the cores from 

 immediately below the surface, partly filled with the roots of plants and other 

 vegetable debris, in the lower cores the interspaces are now either vacant, or filled 

 with a fine detrital mud, either firmly cemented into a hard, dull, whitish rock, or as 

 a loose, incoherent powder, which contains foraminifera, echinid spines, minute 

 stellate spicules of ascidians, fragments of coral, gastropod shells, and pieces of 

 encrusting and branching Lithothamnion. 



The corals""' present belong to Millepora, Heliopora, stems and detached spicules of 

 alcyonaria, referred to the genus Lobophytum, Astrcsa,, Madrepora and Forites. The 

 structure in these corals is usually well preserved, but in many instances their 

 interstices are now so infilled with a deposit of crystalline sclerenchyma and other 

 materials, and further masked by a net work of tunnellings of sponges and other 

 boring organisms, that it is difiicult to make out their original characters. Not 

 infrequently also, where the sedimentary calcareous mud has not penetrated into 

 the interior of the corals, the interstices remain vacant or they are infilled with fine 

 prismatic crystals of " conchite" or aragonite. 



The length of the solid cores obtained (2 feet 10 inches) is somewhat less than 

 one-third of the distance bored. The part of the boring not represented by the cores 

 was composed, according to Professor David, chiefly of foraminifera, belonging to the 

 genera Orbitolites and Tinoporus. Professor David considers that the materials 

 from the surface to a depth of 3 feet below, represent a coral breccia, and the 

 remaining 7 feet a raised reef, with patches of foraminifera and coral sand. 



Details. 



(1) [501]. Length 136 millims. Core cylindrical, consisting of irregular lumps of Millepora nodosa, 

 Heliojjora ccerulea, and Madrepora. The corals are encrusted by layers of Folytrema planum and 

 Lithothamnion. Orbitolites marginalis, Polytrema miniuceum, Tinopm'us hamlatus, and Amphistecjina Lessonii 

 are present. Echinid spines. Stellate ascidian spicules referred to LepAodinum. 



(2) [502]. Length 108 millims. Core cylindrical ; about one-fifth of it consists of a mass of Heliopora 



* As stated pre'^'iously, I propose to include the Hydroeorallinse and the Alcyonaria with the 

 Madreporaria under the general term " Corals." 



2 c 2 



