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Proceedings of the Royal Society 
to 2200 fathoms we have a globigerina ooze mostly made up of sur- 
face shells. At c, in a depth of 2300 to 3000 fathoms, all the surface 
shells are removed from the bottom. No coast detritus reaches this 
area, and we find in the deposit pumice stones, some volcanic 
ashes, manganese nodules, sharks’ teeth, and ear bones of whales. 
It is only in areas like this that we find sharks’ teeth and ear bones 
of cetaceans in any numbers. Some of them from the same haul 
are deeply surrounded with manganese deposit, and contain little 
animal matter ; while others have no deposit on them, and seem 
quite recent. These, and other facts which might be mentioned, 
all argue for an exceedingly slow rate of deposition. Now it is in 
these same areas that the spherules of native iron and other 
magnetic spherules are found, both in the deposits and in the 
manganese nodules from them. 
Finding them in this situation favours the idea that they are of 
cosmic origin, for in such places they are least likely to be covered 
up or washed away. It is certainly difficult to understand why the 
spherules on which the copper is precipitated have not become 
oxidised. If nickel be present in them, this may retard oxidation 
to some extent. 
The manganese depositions in our ocean deposits are very dif- 
ferent in structure and composition from any of the ores of man- 
ganese I have had an opportunity of examining, and the deposits 
of the deep sea far from land have not, so far as I know, any equi- 
valents in the geological series of rocks. 
All the subjects treated of in this paper are still under investiga- 
tion, and at some future time I hope to present a much more 
detailed account. 
These observations seem to me to give ground for the following 
conclusions : — 
