Plate 3. 



Fig. 5. Skeleton of siliceous Sponge, impregnated with the oxides of manganese and iron, 

 from Station 4721, January 15, 1905, lat. 8° 7.5' S., long. 104° 10.5' W., 

 depth, 2084 fathoms. The siliceous spicules are preserved, so that there is no 

 replacement, but deposition. A similar case was observed among the material 

 dredged at Station 4656. 



Fig. 6. Consolidated Globigerina Ooze from Station 4693, December 14, 1904, 

 lat. 26° 30.1' S., long. 105° 45.2' W., depth, 1142 fathoms. This slaggy-looking 

 concretion is mainly made up of the shells of pelagic Foraminifera cemented 

 together by, and subsequently impregnated with, the oxides of manganese and 

 iron, which are irregularly distributed through the consolidated ooze, and do 

 not form concentric layers. 



Fig. 7. Lump of white ashy material, broken off some larger mass, and being enveloped 

 by a coating of manganese-iron oxides, from Station 2, August 27, 1899, 

 lat. 28° 23' N., long. 126° 57' W., depth, 2368 fathoms. A worm burrow tra- 

 verses the white core. This may be taken as a term of transition between cakes 

 of pure white ashy substance and manganese nodules. The white internal por- 

 tions of these nodules are formed of palagonitic tuff, of which Dr. Caspari gives 

 an analysis in the appendix. 



Fig. 8. Section through a typical nodule from Station 2. The white portions are of the 

 same nature as the white core in Fig. 7. The manganese-iron oxides may be 

 seen impregnating the white portion, not deposited in alternate layers round a 

 nucleus : two worm burrows are well shown. 



