ng, off the American coast
to-day. Other lines which start from the level of the primitive
many-celled Algae develop into the Mosses (Bryophyta), Ferns
(Pteridophyta), Horsetails (Equisetalia), and Club-mosses
(Lycopodiales). The mosses, the lowest group, are not preserved in the
rocks; from the other three classes will come the great forests of the
Carboniferous period.

The early record of plant-life is so poor that it is useless to
speculate when the plant first left the water. We have somewhat obscure
and disputed traces of ferns in the Ordovician, and, as they and the
Horsetails and Club-mosses are well developed in the Devonian, we may
assume that some of the sea-weeds had become adapted to life on land,
and evolved into the early forms of the ferns, at least in the Cambrian
period. From that time they begin to weave a mantle of sombre green over
the exposed land, and to play a most important part in the economy of
nature.

We saw that at the beginning of the Devonian there was a considerable
rise of the land both in America and Europe, but especially in Europe.
A distant spectator at that time would have observed the rise of a chain
of mountains in Scotland and a general emergence of land north-western
Europe. A continent stretched from Ireland to Scandinavia and North
Russia, while most of the rest of Europe, except large areas of Russia,
France, Germany, and Turkey, was under the sea. Where we now find our
Alps and Pyrenees towering up to the snow-line there were then level
stretches of ocean. Even the north-western continent was scooped
into great inland seas or lagoons, which stretched from Ireland to
Scandinavia, and, as we saw, fostered the development of the fishes.

As the Devonian period progressed the sea gained on the land, and must
have restricted the growth of vegetation, but as the lake deposits now
preserve the remains of the plants which grow down to their shores, or
are washed into them, we are enabled to restore the complexion of the
landscape. Ferns, generally of a primitive and generalised character,
abound, and include the ferns such as we find in warm countries to-day.
Horsetails and Club-mosses already grow into forest-trees. There are
even seed-bearing ferns, which give promise of the higher plants to
come, but as yet nothing approaching our flower and fruit-bearing trees
has appeared. There is as yet no certain indication of the presence of
Conifers. It is a sombre and monotonous veget