12. By interrogating the nature of the geological beds, one knows in the most positive manner if, at the epoch of their formation, the country which encloses them was occupied by the sea, by lakes, or by forests and plains peopled with terrestrial animals. If, then, in the same country one finds a series of superposed beds containing alternately marine and fresh-water fossils many times repeated, it is an unexceptionable proof that this same country has been many times encompassed by the sea, covered by lakes, and become dry again.
And how many centuries upon centuries certainly, thousands of centuries perhaps has it required to accomplish each period of this? What a powerful force must have been required to displace and replace the ocean, to raise mountains! How many physical revolutions, violent commotions, the Earth has passed through before becoming what it has been through historic ages! And they try to make us believe that the formation of the Earth took less time than is necessary to propagate a plant!