Fig. 1 
Fig. 2 
Fig. 
Fig. 
PLATE XXIX. 
. Section of manganese nodule from Station 285; 2375 fathoms, South Pacific. It shows a zonary 
arrangement of the concretion around a fragment of a shark’s tooth. The alternate zones consist 
of lighter and darker layers, the manganese being accumulated in the dark, and the clayey matters 
more abundant in the light, bands (magnified 37 diameters). 
. Section of manganese nodule from the same station. This concretion contains several nuclei. Near 
the upper part of the figure there is a section of a shark’s tooth, and portions of other teeth may be 
seen in different parts of the figure. Near the lower part there is a volcanic lapilli, containing 
green augite and plagioclase. Around each of these centres the manganese has been deposited in 
a concentric manner, and during the growth of the nodule the numerous other particles have been 
enveloped by the manganese (magnified 37 diameters). 
1. Section of manganese nodule from the same station. This preparation shows the arrangement of the 
manganese under a higher power, the manganese being more abundant in the dark patches, while 
the lighter colour represents the spaces for the most part made up of clayey and earthy matters 
(magnified 145 diameters). 
1. Section of manganese nodule from the same station. This figure shows the zonary arrangement of the 
manganese around two principal centres, and their subsequent envelopment in one nodule by the 
continuous deposition of layers of manganese, which have enclosed at the same time the clayey 
matters with their fragments of minerals and organisms (magnified 37 diameters). 
