beneath the sea level glaciers and deserts and desert deposits
alike must also disappear. Vegetation will clothe the earth,
and marine life swarm in the shallow seas of the broadening
continental shelf. Under the mantle of vegetation, mechanical
erosion will be less, that is, the breaking up of rocks into
small pieces without any very great change, but the rich soil
will be charged with carbon dioxide, and chemical activity will
still go on. Rivers will still contain carbonates, even though
they carry very little mud, and in the oceans the corals and
similar living forms will deposit the burden of lime brought
into the sea by the rivers. Thus, if forces of degradation have
their own way, in time there will be a gradual change in
dominant character, from coarse sediments to fine, from rocks
which are simply crumbled debris to rocks that are the product
of chemical decay and sorting, so that we have the lime
deposited as limestone in one place and the alumina and silica,
in another. We shall have a change from local deposits, marine
on the edges of large continents, or land deposits, very often
coarse, with fossils few and far between, to rocks in which
marine deposits will spread far over the present land in which
will appear more traces of that life that crowded in the
shallow warm seas which form on the flooded continents. We
shall have a transition from deposits which may be largely
formed on the surface of the continents. lakes, rivers, salt
beds and gypsum beds, due to the drying up of such lakes and
the wind-blown deposits of the steppes, to deposits which are
almost wholly marine.

Now, I need not say (to those who are familiar with geology)
that we have indications of just such alternations in times