from their earliest introduction to the present day, corresponding to
their botanical rank as they now exist, so that the series of gradation
in the Vegetable Kingdom, as well as the Animal Kingdom, is the same,
whether founded upon succession in time or upon comparative structural
rank.

Some attempt has been made to reproduce under an artistic form the
aspect of the world in the different geological ages, and to present in
single connected pictures the animal and vegetable world of each period.
Professor F. Unger, of Vienna, has prepared a collection of fourteen
such sketches, entitled, "Tableaux Physionomiques de la Vegetation des
Diverses Periodes du Monde Primitif."

First, we have the Devonian shores, with spreading fields of sea-weed
and numbers of the club-shaped Algae of gigantic size. He has ventured,
also, to represent a few trees, with scanty foliage; but I believe their
existence at so early a period to be very problematical.

Next comes the Carboniferous forest, with still pools of water lying
between the Fern-trees, which, much as they affect damp, swampy grounds,
seem scarcely able to find foothold on the dripping earth. Their trunks,
as well as those of the Club-Moss trees which make the foreground of the
picture, stand up free from any branches for many feet above the ground,
giving one a glimpse between them into the dim recesses of this quiet,
watery wood, where the silence was unbroken by the song of birds or the
hum of insects. We shall find, it is true, when we give a glance at the
animals of this time, that certain insects made their appearance with
the first terrestrial vegetation; but they were few in number and of a
peculiar kind, such as thrive now in low, wet lands.

Upon this follow a number of sketches introducing us to the middle
periods, where the land is higher and more extensive, covered chiefly
with Pine forests, beneath which grows a thick carpet of underbrush,
consisting mostly of Grasses, Rushes, and Ferns. Here and there one of
the gigantic reptiles of the time may be seen sunning himself on
the shore. One of these sketches shows us such a creature hungrily
inspecting a pool where Crinoids, with their long stems, large,
closely-coiled Chambered Shells, and Brachiopods, the Oysters and
Clams of those days, offer him a tempting repast. Here and there a
Pterodactyl, the curious winged reptile of the later middle periods,
stretches its long neck from the water, and birds also beg