10 
ILLUSTRATED NATURAL HISTORY. 
' The fiend, 
O'er bog, o'er steep, tlirough straight, rough, dense, or rare. 
With liead, hands, wings, or feet, pursues Ills way, 
And swims, or wades, or creeps, or flies.' 
"With flocks of sucli creatures flying in the air, and shoals of no less monstrous ichthyosauri 
and plesiosauri swarming in the ocean, and tortoises crawling on the shores of the primeval lakes 
and rivers, — air, sea, and land must have been strangely tenanted in these early periods of our 
infant world." 
In speaking of this age of reptiles, the period of the iguanodon, Dr. Mantell says : " The country 
it inhabited must have beeu diversified by hill and dale, by streams and torrents, the tributaries of 
its mighty rivers. Arborescent ferns, palms, and yuccas constituted its groves and forests ; delicate 
ferns and grasses, the vegetable clothing of its soil ; and in its marshes, equiseta, and plants of a 
like nature, prevailed. It was peopled by enormous reptiles, among which the colossal iguanodon 
and the megalosaurus were the chief Crocodiles and turtles, flying reptiles and birds, frequented 
its fens and rivers, and deposited their eggs on the banks and shoals ; and its waters teemed with 
lizards, fishes, and mollusca. But there is no evidence that man ever set his foot upon that 
wondrous soil, or that any of the animals which are his contemporaries found there a habitation ; 
on the contrary, not only is evidence of their existence altogether wanting, but, from numberless 
observations made in every part of the globe, there are conclusive reasons to infer that mau and 
the existing races of animals were not created till myriads of years after the destruction of the 
iguanodon country, — a country which language can but feebly portray, but which the magic 
pencil of a Martin, by the aid of geological research, has rescued from the oblivion of the past, 
and placed before us in all the hues of nature, with its appalling dragon-forms, its forests of palms 
and tree-ferns, and the luxuriant vegetation of a tropical clime." 
These are some of the extinct animal wonders which geology presents to our view. There were, 
however, almost countless species of others, inferior in size, but often no less curious in their 
structure and endowments. These include whole races of quadrujjeds, birds, fishes, reptiles, insects, 
and still lower organizations. There is hardly a single existing animal which has not its semblance 
in this field of fossil wonders. It Avould seem that for millions of ages the earth has been the' 
theater of a succession of creations of animal forms ; and so multitudinous are these, that the crust 
of the globe is, in great part, composed of their relics. A celebrated author says that "there is 
hardly an atom of its rocks and soil which has not passed through the complex and wonderful 
laboratory of life." All the orders of animals, from the highest to the lowest, have contribated to 
swell the amount of the solid materials of the earth. It is supposed that limestone constitutes one- 
seventh part of the crust of the globe ; and this, with the immense beds of chalk, flint, marl, gyp- 
sum, sandstone, lias, and jasper, are all of animal origin. They are, in fact, the bones and shells of 
the innumerable races which have lived on the earth in ages past, and which, for the most part, 
have become extinct. 
The subject of organic remains constitutes of itself a separate science, to which is given the 
name of Paleontology. The classification of extinct animals has been pursued with great zeal, and 
nearly 25,000 species have been identified. This is a field of wonders, calculated to enlarge our 
view of the boundaries of creation ; but we must now take leave of it, and give attention to those 
animal races which constitute the living inhabitants of our globe, 
PEELIMINAEY REMARKS ON THE CLASSIFICATION OF ANIMALS. 
When we consider the immense number of animals existing on the face of the earth, we are soon 
convinced that an attempt to obtain a knowledge of each of them individually, and without any 
acquaintance with their mutual relationships, would be a hopeless task. We are, in fact, compelled 
to call in the aid of some system of classification, which, by bringing together those animals which 
most resemble each other, and characterizing them by some common point of structure, may enable 
us to form a general idea of the Avhole, and thus to remember more readily the peculiarities of 
each. Some such classification, rough and imperfect as it may be, is, indeed, formed by every obser- 
vant mind ; and its terms find a place in ordinary language. Beasts, birds, and Jishes, reptiles^ 
