46 



BULLETIN OF THE 



an empty space between. When these spaces are filled by a further 

 deposition of lime, the whole becomes very compact and massive. 



The centres of the Foraminifera are frequently filled with a gray or 

 yellowish substance which does not, however, give the reactions of 

 pliosphate of lime. 



The mineral particles were very few in number, among them frag- 

 ments of quartz and plagioclase being observed. This concretion was 

 about two inches in diameter and had a rough areolar surface on which 

 Serpulae and Polyzoa were growing. 



A similar and somewhat larger concretion from 200 fathoms (St. 

 291) was also obtained off' the Barbadoes, which was much more over- 

 grown with organisms, and on its upper surface had a large cavity in 

 which a hermit-crab had lived. (Polycheles Agassizii, see Bulletin VIII. 

 No. 1.) 



Off" the north coast of San Domingo, in 772 fathoms (No. VI.), there 

 were obtained several small manganese Nodules and a few fragments of 

 a Corallium coated with manganese, precisely similar to that dredged by 

 the "Challenger" in 1,52.5 fathoms near the Cape Vcrdcs (see Narrative 

 of the Voyage, page 125). The interior of the nodules were of a liglit 

 brownish color and were composed in all cases chiefly of a mass of pelagic 

 Foraminifera. The largest of these nodules had a diameter of about 

 two inches. Microscopic sections of the nodules and concretions were 

 easily made and showed with great distinctness the structure of the 

 mass, composed chiefly of pelagic Foraminifera cemented together as 

 above stated, 



Stcdion 103. — Old Baliama Channel. Depth, 438 fathoms. Surf. temp. 79° 

 Bot. temp. 49 1°. A Ptcropod ooze or -wliite coral mud, slightly cohereut when, 

 dry, chalky. 



Carbonate of Calcium, 87.06 per cent, consists of Gasteropod, LamelHbranch, 

 Ostracode, Ptcropod and Heteropod shells, calcareous Alga?, Echinoderm frag- 

 ments, Polyzoa, Alcyouium spicules, coccoliths and rhabdoUths, and the following 

 Foraminifera : — 



Glohigerina dubia 



G. rubra 



G. hirsuta 



G. (pquilateralis 



G. {Orbulinu) wiiversa 



Tiihinulina menardii 



P. menardii, var. tumida 



P. mirhdiniana 



Pullenia obliquiloculata 



• Pelagic 

 species. 



Ci/mbalopora buUoides 

 Milioli/ia seminulum 

 M. Uiuifpana 

 M. bicornis 

 M. arjglutinans 

 Biloculina cornuta 

 Pulrinulina sp. 

 Cassidnlina crassa 

 Textularia turris 



