24 NATURAL SCIENCE [Juty 
ventured to say that it would not be a Globigerina Ooze, founding 
that opinion on the fact that only one or two small Foraminifera 
had been observed in the tow-nets for several days. When a 
white-coloured deposit was brought on board from 1260 fathoms 
the laugh was rather against ‘the philosophers, for in external 
appearance it greatly resembled the calcareous oozes of the Atlantic. 
On examination, however, it was found to be a Diatom Ooze with 
only relatively few Globigerina shells. 
The most striking peculiarity in connection with the distribution 
of these dead shells on the floor of the ocean is the fact that they 
are wholly absent from all the greater depths of the ocean, although 
at the surface their living representatives are as abundant over 
these deep areas as elsewhere. If we suppose a volcanic cone to 
rise from the greater depths of the ocean up to within 400 or 300 
fathoms of the surface, it will be found that the summit of this 
cone is covered with a calcareous deposit for the most part made up 
Fic. 5.—Globigerina Ooze, from 1900 fathoms in the Atlantic ; magnified 25 diam. 
of the dead shells of pelagic organisms, the deposit may contain 
90 per cent. of carbonate of lime, and in it every species of shell 
met with in the surface waters of the region is represented. As 
we descend the sides of this cone into deeper water, the thinner 
and more delicate shells, like Candeina and Hastigerina, disappear 
first from the deposit (along with the Pteropod shells). In about 
2000 fathoms the deposit consists chiefly of pelagic Foraminifera, 
and the proportion of young shells is much smaller than in the 
deposits at lesser depths. With increasing depth the whole of 
these calcareous shells gradually disappear, till at 4000 and 5000 
fathoms probably not a vestige of them can be traced, and the 
deposit all round the cone in 3000 fathoms becomes a Red Clay 
