tiful example of the adaptation of structure to the peculiar exigencies of species." In the same waters lived the Ichthyosaurus, another reptile monster of gigantic proportions, often attaining the extraordinary length of thirty feet. It possessed the snout of a Porpoise, the head of a Lizard, the jaws and teeth of a Crocodile, the vertebræ of a Fish, the sternum of the Ornithorhynchus, the paddles of a Whale, and the trunk and tail of a Quadruped. The jaws often opened to the extent of a fathom, and were armed with one hundred and sixty teeth. Its paddles were constructed of more than a hundred octagonal bones, all most admirably connected together. Its organs of vision possessed the most remarkable peculiarities, and were of colossal dimensions, the eyeball sometimes being equal to a twelve-inch globe. "Before the orbit of the eye there existed a circular series of thin bony plates, which surrounded the opening of the pupil. This apparatus, which is met with in the eyes of some birds, and in those of the turtle and lizard, could be used so as to increase or diminish the curvature of the transparent cornea, and thus increase or diminish the magnifying power, according to the requirements of the animal; performing the office, in short, of a telescope or microscope at pleasure. The eyes of the Ichthyosaurus were thus an optical apparatus of wonderful power and of singular perfection. They gave the animal the power of seeing its prey far and near, and of pursuing it in the darkness, and in the depths of the sea. The curious arrangement of bony plates we have described furnished, besides, to its vast globular eye,

the power necessary to bear the pressure of a considerable weight of water, as well as the violence of the waves, when the animal came to the surface to breathe, and raised its head above the waves."

Wonderful, indeed, was the aspect of our world at this remote epoch. Having a brilliant sun, high temperature, and copious showers, nothing in the existing scenery of the globe surpasses the rich and gorgeous vegetation which decorated the continents of the Jurassic period. And wonderful, too, was the population that occupied the earth's seas at this time-Pleisiosauri, Inguanodons, and Ichthyosauri ploughed the waters in every direction, while upon their surface floated innumerable Ammonites in light skiffs, some of them equal to a wagon wheel in diameter. Gigantic turtles and crocodiles also crawled through the marshes or basked upon the banks of lakes and rivers, while flocks of the dragon-like Pterodactyls, with their powerful wings and reptile bodies, were far and near cleaving the air in pursuit of their prey, and swarms of active insects everywhere darting and glittering in the morning and evening sunshine.

It hardly need be said, that in all this we discover nothing like support or countenance to the dream of Evolution-nothing, certainly, to indicate that animal organisms are declining and fading toward Darwin's Ascidians or his Ascidian larvæ.

But peradventure it may be urged, notwithstanding

*Figuire's World Before the Deluge, p. 195.

our incalculable distance from the light of the present day, that we have not yet gone far enough to reach any marked evidence of this prior inferiority-so insensibly slow has been the progress of development. We resume, then, our journey and descending through full half a mile of Triassic and Permian formations, without stopping to notice either their animal or plantal productions—their graceful forests of Green Conifers and Tree-ferns, or their huge Labyrinthodons and Land-turtles and marine Crocodiles-our subterranean road brings us at length to the borders of the Great Coal Measures, which, in layers past enumeration, stretch before us to an average thickness of no less than ten thousand feet. We advance and cross it-what scenes! what productions! what periods! These coal strata, built entirely of the spoils of successive vegetable worlds, with the intervening beds of limestone made up wholly of the fossil remains of innumerable generations-how they all proclaim the prolonged periods occupied in their formation. How countless the ages necessary for their accumulation, when the formation of only a few inches required the life and death of many generations.* Standing here at the base of the Great Carboniferous System, and looking upward over its long and vanishing series of strata, all slowly built up of organized remains, we are filled with awe, and feel that we have reached a date that cannot be remote from the confines of eternity!

We have, indeed, sensibly approached the period when

* Professor Phillips calculates that, at the ordinary rate of progress, it would require 122,400 years to accumulate only sixty feet of coal.

the earth was a molten mass, for here the internal heat of the globe still penetrates its cooling and consolidating crust, producing a high temperature, and a steamy atmosphere, over its whole surface; from pole to pole it has but one climate. The same exuberant vegetation abounds within the polar circles as between the tropics; the tall and graceful Sigillarias, the broad-leaved Lepidodendrons, the fluted Calamites, and elegant arborescent Ferns, with airy foliage as finely cut as the most delicate lace, flourished in Greenland as they did in Guinea, in Melville Island as well as in central Africa. Under this elevated temperature, of land animals we find no traces, except of a few flitting insects. Birds there are none. The seas, however, are occupied by an immense number of zoophytes and molluscans, and also by some crustaceans and Fishes. In the Mountain Limestone, the lowest member of this system, we find the Nautili, and with them the Goniatites, which are far more curi ously constructed than their representatives in the present seas. But we tarry not here to examine or compare.

Though we have now passed through one of the most surprising periods in our planet's history, and have more than doubled the distance of our last halting-place from the light of the living, yet, that our observations may be complete and conclusive, we must still go forward. The mind shrinks, shudders almost, at the thought of plunging still deeper into the abyss of the unfathomable past. We have already reached an era of high temperature-the heat is become oppressive-the atmosphere is semi-opaque through the abounding exhala

tions arising from the warm earth-the sun is growing pale and dim even at his meridian-one shoreless ocean, dotted only with scattered islets, covers the whole face of the globe. Strange and dismal situation! Leaving behind the last footprint of air-breathing animal, and bidding adieu even to the last vestige of land-plants, we pass down into the vast DEVONIAN SYSTEM, whose wondrous records make up a volume of not less than two miles in thickness. The geological character of this immense formation, again, tells of ages innumerable. Though more than ten thousand feet in depth, yet the whole of it is obviously derived from the materials of more ancient rocks, fractured and ground and decomposed, and then slowly deposited in the tranquil waters of the Devonian Sea. The gradual and quiet nature of the process, and therefore of its immense duration, are evident from the numerous platforms of death, which mark its formation, each crowded with organic structures which lived and died where they

now are seen.

"The fossils of this great System are remarkably numerous, and in a state of high preservation. And cer tainly a stranger assemblage of forms have rarely been grouped together;-creatures whose very type is lost, fantastic and uncouth, and which puzzle the naturalist to assign them even their class; boat-like animals, furnished with oars and a rudder;-fish plated over, like the tortoise, above and below, with a strong armor of bone, and furnished with but one solitary rudderlike fin; other fish less equivocal in their form, but with the