we are indebted to the genius of George Cuvier—that I wish to impress.Suffice it to say that all animals are either vertebrated possessed of a backbone; articulated—with an external horny crust, composed of rings, like insects, lobsters, and worms; molluscous-with soft bodies like slugs, very often covered by a shell, like snails and oysters; or radiated-with bodies composed of parts somewhat symmetrically arranged on all sides with reference to the centre, like the starfish and corals. I have named the most striking character which distinguishes each of these great branches of the animal kingdom. All the other parts conform to these; indeed, the basis of each peculiar plan is laid in the nervous system, at a very early period of embryonic development; and the hard parts-the bones and external crust are moulded to this, so that, though the real basis of these distinctions is hidden from view, the external form and proportions become always an infallible exponent of the fundamental plan.

Three of these fundamental plans are called into requisition in the constitution of the very first population of our globe, omitting any consideration of the little-known existences of the Eözoic Time. The coral was a radiate; the Lingula was a mollusc; the trilobite was an articulate. The fourth plan was drawn upon before the close of the first great period of animal history, and was realized in the form of a fish.

In the very first chapter of the book of Nature, then, we read the announcement of a programme which is still in process of execution. The type of the primeval coral has sprouted into the sea-anemone, the sea-nettle, and the starfish. The type of the Lingula has been degraded into the Bryozoan and nummulite, and expanded into the clam, the snail, and the cuttle-fish. The type of the trilobite has varied into the worm below and the insect above; while

the vertebrate type, beginning with the fish, has developed into the reptile, the bird, the quadruped, and man.

Nor does method end here; nor the method which had its first announcement on the morning of animal existence. I have already alluded to the varied conditions under which animal life presents itself—the various ends with reference to which animals have been modified-some to swim, some to fly, some to climb, some to burrow; some for exalted powers and active habits, others for a degraded and sluggish existence. Each fundamental type has been moulded, and warped, and adapted to these varied ends and conditions of being. At the same time, the grand characteristics of the type have been conserved even in the extremest modifications. The modifications of the fundamental plan to adapt it to these various ends are classcharacters; and we thus find that Nature has herself grouped the members of each branch into classes. This method is as old as the animal creation. Not only did each creature which played its part in the primordial fauna conform to one of the four fundamental types of structure, but it also conformed to the characteristics of one of the preconceived class-modifications of that type.

Lastly, each class-group is composed of different grades of animals, constituting so many different orders within the limits of the class. This gradation of ordinal types was also recognized in the organization of the earliest animals.

Thus the whole plan of creation was mapped out to the mind of the Creator in the beginning. We shall see, as we proceed with our sketches of the history of creation, that every step in the evolution of continents, and the establishment of a home for the coming man, was a movement in a definite direction, effected by forces chosen from the first, and shaped always with reference to exigencies which were to arise in the far-distant future. We shall see how

the simple animal forms of the primeval ocean embodied in themselves germs which were capable of unfolding into the richest variety of adaptations and the most exalted capabilities. There can be no nobler, no more instructive and inspiring employment, than to stand where we do, at the end of this long history, and, looking back upon it, catch its method, and reproduce in our own minds the sublime conceptions of the Architect of the World.

и

CHAPTER X.

THE GARDEN OF STONE LILIES.

E have wandered down through the fiery mazes of the præsedimentary ages of the world, and have seen the granite, the quartz, feldspar, and mica, the hornblende, and other first-born products of primeval refrigeration organizing themselves in obedience to the molecular forces of Nature; we have witnessed the floods descending, and cubic miles of sediments settling in the bed of the Eözoic sea; we have gazed upon the first flickerings of animated existence, and have noted the fact that while Nature established the procession of organic being with the four sub-kingdoms of animals nearly abreast of each other, the van of each was led by some of the weakest and most abnormal forms which have ever appeared within the circle of their respective types.

The conditions of existence during the St. John's and Potsdam periods must have been somewhat uniform under all meridians. No continents existed to divert the tidal current into cooler or warmer latitudes, or unequalize the temperature of the atmosphere by their superior power of absorbing and radiating heat. The leading types of existence were trilobites-exhibiting a close relationship with each other on whichever side of the world we exhume their mummied forms-and some inferior brachiopods, which are almost identical in species at St. Petersburg, and at Keeseville, New York. We have seen that the central portions of the American continent constituted at this time a vast basin of shallow water, the rim of which extended all

E 2

around the frontier of the Middle and Northern States. In this magnificent lagoon the Iron Mountain of Missouri loomed up, as it now does-an island of metal-the apex of an iron cone, whose base rests broadly and deeply on the molten ocean which floats kingdoms and continents from the past eternity to the future. Around its sloping flanks the sediments of the Potsdam period accumulated in horizontal layers, which to-day may be witnessed abutting against the dark sides of the emerging cone of metal. A few other isolated points had thus early been born from the abyss.

In such a sea-a shoreless sea-lived, and lived in happiness, those problematical forms called trilobites, whose remains have been opened from the solid rocks of Wisconsin, Vermont, Canada, and hundreds of other localities. Rather, on such a submarine platform they sported their day, for on all sides-certainly toward the east, south, and west-the waters deepened, as now, to an almost unfathomable depth, to whose dark recesses life never gropes its way (Fig. 38).

"The

In the progress of the earth's preparation this act of the drama closed, and the curtain fell upon the scene. curtain rose, and the scene was changed." The beings which teemed in the waters of the preceding epoch were buried in the ruins of a convulsion which marked the advent of a new æon. Not an individual of any of the former species outrode the storm. But the sea is now quiet again -more quiet than before. The waters are clearer. The floor of the ocean has settled a few hundred feet deeper, and the conditions of our planet are changed. Lo! now the clearer and quieter waters are teeming with myriads of new existences, some of which reproduce the family features of the beings of the preceding period, while others are forms now first revealed upon our planet. Whence come