[Audubon's works are] the most splendid monuments which art has erected in honor of ornithology.

My object will be, first, to show by what connections the history of the fossil bones of land animals is linked to the theory of the earth and why they have a particular importance in this respect.

It is evident that one cannot say anything demonstrable about the problem before having resolved these preliminary questions, and yet we hardly possess the necessary information to solve some of them

Moreover, it thus follows that not a great deal of time was needed for the large animals of the three major parts of the world to become known to the people who spent time on the coasts of those regions.

The traces of upheavals become more impressive when one moves a little higher, when one gets even closer to the foot of the great mountain ranges. There are still plenty of shell layers. We notice them, even thicker and more solid ones.

Why has not anyone seen that fossils alone gave birth to a theory about the formation of the earth, that without them, no one would have ever dreamed that there were successive epochs in the formation of the globe.

All organs of an animal form a single system, the parts of which hang together, and act and re-act upon one another; and no modifications can appear in one part without bringing about corresponding modifications in all the rest.