no more reason for believing that the different species or forms of
animal life were suddenly introduced than there is for believing
that the soil, or the minerals, gold, silver, diamonds, or vegetable
mold and verdure were suddenly introduced.




II



If we know anything of the earth's past history, we know that the
continents were long in forming, that they passed through many
vicissitudes of heat and cold, of fire and flood, of upheaval and
subsidence--that they had, so to speak, their first low, simple
rudimentary or invertebrate life, that they were all slow in getting
their backbones, slower still in clothing their rock ribs with soil
and verdure, that they passed through a sort of amphibian stage, now
under water, now on dry land, that their many kinds of soils and
climes were not differentiated and their complex water-systems
established till well into Tertiary times--in short, that they have
passed more and more from the simple to the complex, from the
disorganized to the organized. When man comes to draw his sustenance
from their breasts, may they not be said to have reached the
mammalian stage?

The fertile plain and valley and the rounded hill are of slow
growth, immensely slow. But any given stage of the earth has
followed naturally from the previous stage, only more and more and