of the animal of the Belemnite, a characteristic fossil of the Oolitic group, have been thus preserved in indurated clays, and of the cuttle-fish in limestones. The delicate impressions of plants of the various epochs stamped in the sandstones, shales, coals, and chalks, are presented with the utmost fidelity. The silicious shells of animalcules are everywhere abundant; in our own country whole districts are composed of them; in Virginia, New Jersey, New York, Massachusetts, Michigan, and Iowa, and probably every state of the Union, their remains are more or less common. In a previous chapter we have admired the construc. tions of the coral-animal, and considered with a feeling of astonishment and wonder, the immense importance of the labors of so apparently helpless and insignificant a being; but what shall we say to the beds of rocks, composed of the remains of animalcules invisible to the eye? yet of such are the pyramids built! Not only are the carapaces, or shelly coverings, of these minute animals preserved, but in many instances the fleshy parts of certain minute chambered shells are admirably preserved, imbedded in the heart of a flint nodule, and one familiar with such appearances, can in the merest fragment of flint, detect various organic bodies. The variety of limestone called encrinital marble, is composed almost wholly of a peculiar stony animal called the Encrinite, and particularly abundant in the carboniferous, or mountain limestone, of the carboniferous group. A specimen from the Helderbergh Mountains near Albany, lies before us, compact and firm as though originally composed of crystaline materials. The ordinary observer can form but little idea of the amount of organic remains distributed throughout the various strata. In the following chapters we shall consider in order the three great epochs, or periods of the earth's existence as demonstrated from the study of fossil animal and vegetable remains. The first epoch commences with the granitic period, or period antecedent to the introduction of life, and ends with the carboniferous or great coal formation. The second period commences with the new red sandstone, and ends with the cretaceous or chalk system. The third and last period embraces what are termed the tertiary deposits. We would refer the reader to the chart on page 194, where these divisions will appear marked according to Dr. Buckland, under the names primary, transition and secondary, and tertiary. It will only be possible to give a very superficial sketch of the probable condition of our planet during these several epochs, but we shall endeavor to convey a clear idea of the succession of animal and vegetable life which so strongly characterizes them, so that the reader will be prepared to enter upon a more extended investigation. It is almost impossible even when writing upon ordinary topics, to avoid the use of technical terms, and perhaps least of all can this use be avoided, when natural history becomes the subject. There is nothing of so much benefit, both in economising the time of the student, and in assisting his memory, as a correct and intelligible system. A well selected name; expressive of peculiar characters, or habits, or localities, conveys a multitude of ideas to the mind, which a common er vulgar name would entirely fail to do, for this reason we shall use the names generally applied by geologists to the several fossils, giving in all cases, their meaning or translation, whenever these words are derived either from the Greek or Latin. The word fossil, which we have often used, meant originally, what was dug out of the earth, it is now however applied only to the remains of organic matter. The fossil animal kingdom may be divided into six sections. I. INFUSORIA, or Animalcules. The name infusoria is derived from the presence of many genera, or groups of species, in vegetable infusions, not easily observable without the microscope. II. ZOOPHYTES, or Animal Vegetables, a term applied to corals and other animals supposed to resemble plants; the subdivisions of this group are, 1. AMORPHOZOA, or animals of no regular shape like sponges and 2. POLYPARIA, or many producing animals as the corals. III. ECHINODERMA, or spiny skinned animals, subdivided into, 1: Crinoidea, or Encrinital, i. e. lily or cup-shaped animals. 2. ASTERIA, or star-formed, like the star-fish. 3. ECHINIDA, or spiny animals, like the sea-urchin, or sea-egg. DIVISION OF THE ANIMAL KINGDOM. 301 IV. MOLLUSCA, or soft bodied animals, destitute of bones, under this head are embraced the fossil shells. 1. BIVALVES, or consisting of two pieces like the oyster and clam. 2. UNIVALVES, or consisting of one shell like the snail and periwinkle; these latter are the true molluscs, and are of a higher degree of organization than the former, possessing a head and eyes, of which the former are destitute. 3. CHAMBERED shells like the nautilus, including both the testaceous or shell covered genera, and naked molluscs as the cuttle-fish. 4. CIRRIPEDIA, or hairy-footed animals, like the barnacle. V. ARTICULATA, or jointed animals, comprising, 1. ANNELATA, or ringed animals, like the red blooded worm. 2. INSECTA, or insects, i. e. having the body nearly divided in two, like the wasp and fly. 3. ARACHNIDA, or spiders. 4. CRUSTACEA, having a crustaceous skin like crabs and lobsters. VI. VERTEBRATA, or animals having a spinal column or backbone, subdivided into, 1. Pisces, or fishes. 2. REPTILIA, or reptiles. 3. AvEs, or birds. 4. MAMMALIA, or animals giving suck. The animal kingdom is divided into the above great classes, and these are subdivided into a vast number of species, each being characterized by some peculiar and distinguishing mark. The expert anatomist can often from the mere inspection of a tooth, or a claw, determine the character and habits of an animal. Oftentimes this, or even a foot-print in the sand, is all that remains of some now extinct creature, yet by analogy, instituting a rigid and close comparison with existing species of the same genera, the peculiarities are distinctly made out, and many remarkable facts are brought to light. We now proceed to consider the probable condition of our planet during the stages of existence before enumerated. N CHAPTER XIII. The first Epoch. The land that hath no summer flowers, The wild, dim, polar solitude: How different from this land of ours!" Mary Howitt. THE first great period, commences with the granitic and ends with the coal formation. Beneath the most ancient deposits lies a crystaline rock which, under the name of granite, is familiar to to every one. Lofty mountain chains, sometimes rearing their Alpine summits far beyond the limit of perpetual snow, look down in solitary grandeur upon the scenes below. The hardest and most indestructable of all rocks, it seems fitted for the foundation or superstructure of the entire mass. Occasionally it is found of a more recent origin, exhibiting the appearance of having been ejected after the deposition of the newer strata; probably the result of intense heat acting under great pressure. We may suppose then that there was a time, "the beginning," when a globe existed having alternations of stone and water, no soil was upon its surface, which was a bare rock, presenting innumerable rugged peaks; not a sea-weed floated in the waters, nor a lichen grew on the rock; no sound was there except the monotonous and angry dash of the waves upon the bare and desolate coast. But even then, the atmosphere, perhaps surcharged with carbonic acid, was actively engaged in crumbling down the barren rocks, and we may suppose that the waves and the winds urged their combined force as now; the fragments of granite thus torn off, were deposited in the bed of the ocean, and we find them compacted under the name of gneiss. If during this action, the felspar was partly decomposed, then the quartz or silex, would be deposit ed alone, and subsequently the felspar and mica, either in the form of mica schist, which is composed of layers of mica and quartz, or slaty rocks without fossils; these are the strata which lying immediately upon the granite, and presenting marks of aqueous deposition, yet partake more or less of the crystaline character of the primitive rocks. During all the long period of the deposition of these rocks, formed from disintegrated granite, not a living thing moved, either on the dry shores or in the deep. Perhaps a few animalcules existed in the clear waters, but we have no distinct traces of them; all was silent, the stillness of absolute death. During this period however, great volcanic convulsions occurred, the yet soft masses of gneiss and schistose slates were upheaved, and in many cases rent open and molten masses of granite and basalt flowed through. The metals, melted by the intense heat, were injected into the narrow fissures, and innumerable dykes and veins were formed. In some instances the masses of melted trap rock have crystalized upon cooling, in regular hexagonal prisms. Such are the columns which compose the celebrated Fingal's Cave, exhibited in the wood-cut below. Directly associated with the contorted masses of mica schist to which we have just alluded, there is a coarse slaty rock, exhibiting still more clearly the marks of aqueous deposition, but by far the most interesting circumstance connected with this deposit, is the first appearance of animal life. . We must consider with no little interest, the fossil remains of these early rocks; among |