I have long discovered that geologists never read each other's works, and that the only object in writing a book is a proof of earnestness.

On seeing the marsupials in Australia for the first time and comparing them to placental mammals: “An unbeliever . . . might exclaim 'Surely two distinct Creators must have been at work'”

... probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed.

Every new body of discovery is mathematical in form, because there is no other guidance we can have.

The theory which I would offer, is simply, that as the land with the attached reefs subsides very gradually from the action of subterranean causes, the coral-building polypi soon raise again their solid masses to the level of the water: but not so with the land; each inch lost is irreclaimably gone; as the whole gradually sinks, the water gains foot by foot on the shore, till the last and highest peak is finally submerged.

we are always slow in admitting any great change of which we do not see the intermediate steps

The expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.