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Proceedings of the Royal Society 
of volcanic material in an advanced state of decomposition, 
and of cosmic dust, at points far removed from the continents, 
prove this. There is no reason for supposing that the parts 
of the ocean where these vertebrate remains are found are more 
frequented by sharks or cetaceans than other regions where they 
are never or only rarely dredged from the deposits at the bottom. 
When we remember also that these ear-bones, teeth of sharks, 
and volcanic fragments, are sometimes incrusted with two centi- 
metres of manganese oxide, while others have a mere coating, 
and that some of the bones and teeth belong to extinct species, we 
may conclude with great certainty that the clays of these oceanic 
basins have accumulated with extreme slowness. It is indeed almost 
beyond question that the red clay regions of the central Pacific con- 
tain accumulations belonging to geological ages different from our 
own. The great antiquity of these formations is likewise confirmed 
in a ^strikmg manner by the presence of cosmic fragments, the nature 
of which we have described.* In order to account for the accu- 
mulation of all these substances in such relatively great abundance 
in the areas where they were dredged, it is necessary to suppose the 
oceanic basins to have remained the same for a vast period of time. 
The sharks’ teeth, ear-bones, manganese nodules, altered volcanic 
fragments, zeolites, and cosmic dust, are met with in greatest 
abundance in the red clays of the central Pacific, at that point on 
the earth’s surface farthest removed from continental land. They 
are less abundant in the Eadiolarian ooze, are rare in the Globi- 
gerina, Diatom, and Pteropod oozes, and they have been dredged 
only in a few instances in the terrigenous deposits close to 
the shore. These substances are present in all the deposits, but 
owing to the abundance of other matters in the more rapidly 
forming deposits their presence is masked, and the chance of 
dredging them is reduced. We may then regard the greater or 
less abundance of these materials, which are so characteristic of a 
true red clay, as being a measure of the relative rate of accumula- 
tion of the marine sediments in which they lie., The terrigenous 
deposits accumulate most rapidly, then follow in order Pteropod ooze, 
Globigerina ooze, Diatom ooze, Eadiolarian ooze, and, slowest of all, 
red clay. 
* “On Cosmic and Volcanic Dust,” Proc, Roy. Soc. Edin, 
