Report of the Progress of the Sciences in France. 437 
fossil plants, shells which form the major part of a great num- 
ber of stones, fossil bones, several saline substances of these 
stratifications.” 
The mass of the terrestrial globe augmenting, ought to pro- 
duce changes in its relations with the other planetary bodies: 
their mutuat attractions will change. The sun, on the other 
hand, perhaps loses part of its mass. It appears clear to me, 
therefore, that after some centuries great changes will take place 
upon our globe. This was the doctrine of the ancient philoso- 
phers, Ovid makes Pythagoras say in his Metamorphoses, 
book xv. 
Nihil eqnidem durare diu sub imagine eadem 
Crediderim. 
Lucretius has also said, book v. 
— multosque per annos. 
Sastentata ruet moles et machina mundi. 
But of what nature will these changes be? We are not in 
possession of a sufficient number of facts to be able to predict 
their nature, 
As to the hypothesis of De Luc, who has advanced that the 
existence of the human spectes is posterior to that of other spe~ 
cies, it appears to me to be defective. We do not find, he says, 
fossil human skeletons. To this I answer ; 
1. We find only about 12 species of known quadrupeds, and 
from 16 to 1S genera. Are we to conclude that none of the 
other species and genera existed at the epoch in question ? 
But, it is added, the human species is now-a-days so multi- 
plied.—It is easy to answer that the human species was not, at 
that period, so numerous as it has been since large societies have 
been formed. j 
3, Lastly, we know that the bones of the largest animals 
which die in the fields, in the woods, &c, are speedily decom- 
posed if they are exposed to the air. We do not find in our fo- 
rests any bones of our modern boars, stags, and wolves, nor in 
Africa any bones of the elephant or rhinoceros. 
4. Those which are fossil have been preserved, therefore, by 
being enveloped soon after the death of the animal in earth or 
sand. This event must have taken place under extraordinary 
and unexpected circumstances. Thus we meet with very few 
fossils of quadrupeds, fishes, birds, and vegetables, in compa= 
rison with the immense quantity which has existed. 
It is otherwise with fossil shells: they are very abundant. 
Nevertheless this quantity is very small when compared with 
those which have existed; and we ought to consider well, that 
we find in some places immense heaps of shells of various coun- 
Ee3 tries, 
