REMARKS ON MR. DARWiN's THEORY. 
185 
proved by the small horizontal extent of the various deposits which 
make up a formation, and which generally extend further in propor- 
tion to the fineness of the sediment of which they are composed. I 
think, therefore, that even taking into consideration submarine 
volcanos, we may safely conclude that no deposition is going on now 
over at least one-fifth of the area of the ocean. 
In the present state of the globe about one-fourth of its surface is 
land : if we add to this one-fifth of the ocean we have two-fifths of 
the surface of the globe on which no deposition is taking place ; and 
when we think that deposition could never have been universal, but 
that there must always have been large areas of denudation, we may 
feel sure that this is not very far from the truth. We may therefore 
conclude that the periods of repose in any one area are to the periods 
of deposition in about the ratio of two to three. 
We now know that the deep sea is inhabited ; and if we suppose 
that on equal areas the average number of the inhabitants of the shallow 
sea are to those of the deep sea as eight to one, and to the inhabitants 
of the land as one to three and a half — both suppositions may, I think, 
be safely made — we find that the number of the inhabitants of the 
areas of repose are to the number of the inhabitants of the areas of 
deposition as three is to two. It therefore follows that at least one-half 
of the animals and plants live in places where their remains can only 
be very rarely preserved. And this calculation will apply also to the 
ancient world ; for if the present ratio of land to water, viz. one-third, 
should not bo the average we should still arrive at very nearly the 
same conclusion ; for if it should be greater, it is evident that the 
ratio of the inhabitants of the areas of repose to those of the areas of 
deposition would be increased ; if, on the contrary it should be less, 
the land would be more divided into islands, with of course a larger 
coast line and larger areas of shallow sea ; but the supply of sediment 
from the land would also be reduced and many parts of the shallow 
sea, which if near a continent would be areas of deposition, will near 
an island be areas of repose, while at the same time they will be, 
perhaps, more thickly inhabited. 
But even where deposition is taking place, the burying of organic 
remains in all deposits but limestone is perhaps the exception, and not 
the rule. For if the deposition is rapid vegetable life, and conse- 
quently animal life, cannot flourish. If on the contrary it is slow, all 
bodies must lie for a long time uncovered on the bed of the sea, while 
there all the soft parts will either be eaten or decay, and the rest, 
subjected to the action of the tides or currents, which are generally 
found where deposition is going on, will often be broken, worn down, 
and destroyed. 
From these considerations we must infer that the number of organic 
remains imbedded bears but a small propoi^ion to those that have 
lived. But even after having been safely imbedded, the chances are 
much against a fossil ever finding its way into the cabinet of a 
collector. If buried in sand it is almost sure to be destroyed by the 
percolation of water, and all trace of it removed ; and in any case it 
VOL. IV. X, 
