It may be asked, how any clue can be found to phenomena so evanescent as
those of clouds and moisture. But do we not trace in the old deposits
the rainstorms of past times? The heavy drops of a passing shower, the
thick, crowded tread of a splashing rain, or the small pinpricks of a
close and fine one,--all the story, in short, of the rising vapors,
the gathering clouds, the storms and showers of ancient days, we find
recorded for us in the fossil rain-drops; and when we add to this the
possibility of analyzing the chemical elements which have been absorbed
into the soil, but which once made part of the atmosphere, it is not too
much to hope that we shall learn something hereafter of the meteorology
even of the earliest geological ages.
The peculiar character of the vegetable tissue in the trees of the
Carboniferous period, containing, as it did, a large supply of
resin drawn from the surrounding elements, confirms the view of the
atmospheric conditions above stated; and this fact, as well as the damp,
soggy soil in which the first forests must have grown, accounts for the
formation of coal in greater quantity and more combustible in quality
than is found in the more recent deposits. But stately as were those
fern forests, where plants which creep low at our feet to-day, or are
known to us chiefly as underbrush, or as rushes and grasses in swampy
grounds, grew to the height of lofty trees, yet the vegetation was of an
inferior kind.
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