hen we pile up the winter fire,--in
the brilliant gas that now casts its light on this great assemblage, and
that lightens up the streets and lanes of this vast city,--in the
glowing furnaces that smelt our metals, and give moving power to our
ponderous engines,--in the long dusky trains that, with shriek and
snort, speed dart-like athwart our landscapes,--and in the great
cloud-enveloped vessels that darken the lower reaches of your noble
river, and rush in foam over ocean and sea. The geologic evidence is so
complete as to be patent to all, that the first great period of
organized being was, as described in the Mosaic record, peculiarly a
period of herbs and trees, "yielding seed after their kind."

The middle great period of the geologist--that of the Secondary
division--possessed, like the earlier one, its herbs and plants, but
they were of a greatly less luxuriant and conspicuous character than
their predecessors, and no longer formed the prominent trait or feature
of the creation to which they belonged. The period had also its corals,
its crustaceans, its molluscs, its fishes, and in some one or two
exceptional instances its dwarf mammals. But the grand existences of the
age,--the existences in which it excelled every other creation, earlier
or later, were its huge creeping things,--its enormous monsters of the
deep,--and, as shown by the impressions of their footprints stamped upon
the rocks, its gigantic birds. It was peculiarly the age of egg-bearing
animals, winged and wingless. Its wonderful _whales_, not, however, as
now, of the mammalian, but of the reptilian class,--ichthyosaurs,
plesiosaurs, and cetiosaurs,--must have tempested the deep; its creeping
lizards and crocodiles, such as the teliosaurus, megalosaurus, and
iguanodon,--creatures some of which more than rivalled the existing
elephant in height, and greatly more than rivalled him in bulk,--must
have crowded the plains or haunted by myriads the rivers of the period;
and we know that the footprints of at least one of its many birds are
fully twice the size of those made by the horse or camel. We are thus
prepared to demonstrate, that the second period of the geologist was
peculiarly and characteristically a period of whale-like reptiles of the
sea, of enormous creeping reptiles of the land, and of numerous birds,
some of them of gigantic size; and, in meet accordance with the fact, we
find that the second Mosaic period with which the geologist is call