REPORT ON MATERIALS FROM THE B0RTN(4S AT FUNAFUTI ATOLL. 231 



planum forms thick layers round the corals, sometimes alternating with Litho- 

 thamnion. The detached joints of Halimeda are numerous, and fairly well preserved, 

 they form a distinct feature in some of the cores. Alcyonarian spicules and echinid 

 spines are also present. There is a sudden change in the character of the rock, 

 which in No. 3 1 3 appears to be a limestone, and in No. 3 1 4 is largely dolomitic. 



Details. 



(313). Length 90 millims. Cylindrical core, mth several irregular fragments, rounded by drill. 

 Whitish, cavernous limestone, with numerous pores, lined by scalenohedral crystals. Small hollow casts of 

 PocilJopom, and an undetermined coral. Infilled Cliona l)orings in the cavities from which the corals have 

 been removed. A microscopic section [541] shows the rock to be mainly of fine detrital materials, with 

 broken up and entire foraminifera, including Carpenteria, Pol yt re ma nuniaceuiit, and Gi/jjsina. 



(314). Length 103 millims., diameter 56 millims. Cylindrical core, of hard, mottled or speckled 

 greyish-white, porous dolomitic limestone. The pores of the rock lined with rhombohedral crystals of 

 dolomite. The foraminifera and other organisms more distinctly shown under a lens than in the preceding 

 cores. One or two small casts of Madrepora, encrusted by thick layers of Polytrema planum. Greater part 

 of core of fragmental materials with foraminifera [676, 677], including Miliolina, Polytrema miniaceum, 

 Carpenteria, Amphistegina, and Heterostegina. Halimeda, common. Alcyonarian spicules, echinid spines. A 

 peculiar hollow, thin-walled oval body, 50 millims. long by 31 millims. in width, is present in this core. 

 The wall, about 0"5 millim. in thickness, consists of numerous delicate laminse, of which those near the 

 exterior of the shell are closer arranged than the inner ones. The interior is now filled with foraminifera 

 and fragments. 



(315). Length 90 millims. Cylindrical core of speckled greyish- white, nearly compact dolomitic lime- 

 stone. A single cast of Madrepora. Core mainly fragmental, with Polytrema, Ainipjhistegina, and 

 Heterostegina. Echinid spines. 



(316). Length 77 millims. Cylindrical, hard, speckled, whitish-grey dolomitic limestone, porous in 

 places, and with some cavities. Pores lined by rhombohedral crystals. Branching Madrejjora, overgrown 

 by Polytrema planum. Structure of coral replaced by crystalline dolomite, and the interspaces filled in by 

 detrital mud. Larger part of core of fragmental material [542, 543], with Carp)enteria, Amphistegina, and 

 Heterostegina. Halimeda, common. Echinid spines, alcyonarian spicules retaining their normal fibrous 

 structure. Cliona-horings, solidly infilled with sediment. The rock cemented by dolomite. Cast of 

 gastropod. 



(317). Length 66 millims. Cylindrical core, whitish-grey, hard, porous. Cast of Madrepiora, Halimeda, 

 common. 



(318). Length 66 millims. Core cylindrical, hard, greyish-white, porous, dolomitic limestone. A coral 

 cast, perhaps Hydnophora, encrusted by thick bands of Polytrema 2)lanum. Larger part of core, consisting of 

 fragmental materials [544], with Textidaria, Carpenteria, Polytrema m/iniaceum, Gypsina glohdus, Ampjhistecjina, 

 and Heterostegina. Halimeda, very abundant, the canal structure preserved ; echinid spines. 



(319). Length 45 millims. Cylindrical core, with several pieces of rock rounded by drill. Fragmentary 

 cast of small fungid coral. Polytrema. Echinid spines, Halimeda, common. 



(320). Length 92 millims. Core cylindrical, hard, mottled, greyish-white dolomitic limestone, porous in 

 places. Occasional casts of small corals, replaced hy dolomite. Core mostly of fragmental materials 

 [545, 546], with numerous foraminifera, determined by Mr. Chapman to belong to Spirolocidina, 

 Textidaria, Orbitolites, Gyrahalopora?, Carpenteria, Pvhinulina, Globigerina, Polytrema miniaceum, Amphistegina, 

 and Heterostegina. Alcyonarian spicules ; echinid spines. Serpida, Halimeda joints, showing structure ; 

 Lithothamnion. 



