230 DE. G. J. HINDE. 



The rock contains occasional casts of Madrepora aud Stylophora, but the larger 

 proportion is of consolidated organic calcareous sediment with entire and fragmentary 

 foraminifera, echinid spines, casts of gastropods and ol Halimcda, cemented by 

 calcite. The loose materials brought up by the pump, consist of small angular chips 

 of limestone, similar to that in the solid cores. 



Details. 



(307, 308). Total length 100 niillinis. One piece of cylindrifal core and one irregular fragment. The 

 rock, hard, greyi.sh-\vhite, very cavernous as well as porous. In one of the larger hollows, casts of 

 MafJrepora and the infilled borings of Clwiui. A microscopic section [675] shows that it consists mainly 

 of fine detrital sediment with numerous entire and fragmentary forms of MUioJina, Globifffrina, rare, 

 Carpenteria, Piilvinvlina, Poli/frnnn )irivuic/'>nii, 1'. /ildiumi, ylinphis^tcfjinn, and Ilrfcrofifcgina. Echinid spines. 



(309). Length 50 milliins. A piece of the usual poi'ous white limestone, rounded hy drill. In thin 

 sections [539, 540] it is seen to consist of fine-grained sediment cemented l)y calcite, with Sj>lroJor)i1iii<i, 

 Ghihir/erinci, Cfirprnfnia, Tiiivmtiilind, J'aJi/firiiKi, (liip^ina, and J iiijihixfcfiinn (?) Echinid spines. 



(310). Length 18 millims. An irregular fragment of lock similar to preceding. 



(311). Length 63 millims. Core cylindrical, of the usual whitish-grey limestone with numerous hollows. 

 The only objects visible under a lens are echinid spines and casts of gastropods. 



(312). Length 45 millims. by 56 millims. in diameter. Core cylindrical, of hard whitish limestone, like 

 the preceding. Cast of Sfi/lojihom. Echinid spines, and gastropod casts. The larger part of the core 

 apparently consists of fine sedimentary materials cemented by calcite. 



DeptJi from Surface, G37-643 feet; Difitaiice Bored, (5 feet ; Total Lenxjtli of Core 

 Ohrained, 2 feet 1 inch; Numbers of Cores, 313-320. 



The solid cores from this ])()rti()u of the boring are, for the most part, cylindrical, 

 with some irregular fragments rounded I)y tiie drill. The first piece of the core (No. 

 318) from approximately the level of 637 feet is a whitish, moderately hard, cavei"nous 

 and porous limestone, of similar characters to the solid cores in the preceding 60 feet 

 of the boring. The remaining cores, Nos. 314-320. from between 638-643 feet, 

 differ from those immediately above in being harder, less cavernous, and generally 

 more compact. The rock is greyish -white, not infrequently speckled ; the whitish 

 spots representing the foraminifera and other organisms, and the greyish portions the 

 crystalline infilling. This is markedly different from that in the core above, where 

 the partially free crystals lining the poies are scalenohedral, whereas in these lower 

 cores they are for the most part rhombohedral, and are now dolomitic. Accompanying 

 this change, the organisms in the rock are better shown, and can be readily 

 distinguished with a lens. Coral casts are only occasionally present, they form but a 

 small proportion of tlie cores, and they are in very poor jjreservation. Pocillopora, 

 Hydnophora fi), and Madre2)ora are the only genera recognised. As usual, their 

 structures have been dissolved, and they have been subsequently replaced by 

 crystalline dolomite, while the interstices and the parasitic borings of Cliona, &c., 

 have been infilled with fine organic sediment. The larger ])art of these cores consist 

 of foraminifera of the same kinds as in the cores above ; the encrusting Polijtrema 



