PLATE II. 
Fig. 1 . A very characteristic manganese nodule as regards shape and general appearance (natural size). Over 
thirty nodules more or less like this one were procured at this station. The general form is round, 
and the mammillae are not prominent, but run the one into the other without forming marked 
reliefs. The upper and under surfaces present a sensible difference of aspect. The inferior 
surface, here figured, we believe to have been plunged into the ooze ; it is covered with an immense 
number of rugosities, — little rounded points 1 or 2 mm. in diameter, and the same in height, — 
which, being scattered over tlie whole surface, render the nodule rough to the touch, and some- 
what like shagi’een. These asperities are not so abundant on the upper surface, which is on the 
whole much smoother. Station 248 ; 2900 fathoms. North Pacific. 
Fig. 2. Similar nodule (natural size), in the interior of which were found the remains of a siliceous Sponge 
{Farrea). A portion of the skeleton of the Sponge is represented, more highly magnified, in fig. 
2a ; the minute canals of the Sponge are seen to be filled with manganese. Some portions of the 
siliceous skeleton appear to have been removed by solution. The nodule has probably been formed 
round a fragment of a Sponge. Station 248 ; 2900 fathoms. North Pacific. 
Fig. 3. Irregular pyramidal-shaped variety of nodule (natural size). The nodule is wedge-shaped, and the 
entire surface is mammiUated. The reliefs are more or less pronounced in two directions, the first 
being parallel to the lateral edges of the wedge, along radii, the second being more or less parallel 
to the superior surface of the figure, and following a curved direction. Station 160 ; 2600 fathoms. 
Southern Ocean. 
Fig. 3a. Section showing the internal structure of a nodule similar to the preceding (natural size). The alter- 
nating zones, from 1 to 2 mm. in diameter, are yellowish white and black-brown. The light 
coloured bands are traversed by dendritic depositions of manganese, which is in greater abundance 
in the dark layers. Station 160; 2600 fathoms. Southern Ocean. 
Fig. 3b. Portion of one of these nodules from which the manganese has been removed by concentrated hydro- 
chloric acid. An examination of these clayey skeletons shows that the yellowish white matter 
extends also into the black bands in the interior of the nodule. Station 160; 2600 fathoms. 
Southern Ocean. 
Fig. 4. Section of one of the larger nodules from the North Pacific (natural size). The external surface is 
similar to that of fig. 1. The several white nuclei are found on examination to bo highly-altered 
fragments of pumice, around which layers of manganese have been deposited, the whole being 
ultimately fonned into one nodule. Station 248 ; 2900 fathoms. North Pacific. 
Fig. 5. One of the larger notlules from the South Pacific (natural size). The interior of these nodules consists 
of light brown concentric layers arranged round small altered volcanic fragments, or sharks’ teeth 
an<l their fragments. The outer layens, for a depth of about 5 mm., are of a much darker colour 
than the inner ones. Station 285 ; 2375 fathoms. South Pacific. 
Fig. 6. Five instances of small sharks’ teeth, and little pellets of pumice, surrounded and cemented together 
by depositions of the hydrated j)eroxide of manganese (natural size), showing, as it were, the 
nodules in process of formation arouml various nuclei, and their agglomeration into larger nodules. 
Station 286 ; 2335 fathoms. South Pacific. 
Fig. 7. Four small no<lules (natural size) in a later stage of growth, so to speak, than those represented in fig. 6. 
Tlic nuclei in both coses are of the same nature. Station 285 ; 2375 fathoms. South Pacific. 
