Puate 3. 
Fic. 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. 
Fie. 6. Consolidated Globigerina Ooze from Station 4693, December 14, 1904, 
lat. 26° 30.1/8., 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. 
Fra. 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. 
