their elevation from the bed of the Mediterranean, to volcanic action of recent date; half the peninsula of Italy in fact, is known to have arisen from the depths of the Adriatic; Venice, its far-famed " queen," standing upon the lowest and last-raised portion of its oozy bed.

Had Nature exhibited an invariable constancy in her movements-had a uniformity of operation been observed throughout every period of the earth's history, in the causes which have produced the geological phenomena, we should only require to know the amount of diurnal action, in order to calculate the effects produced in a lapse of ages, in the same manner as the laws which govern the planetary system, and the remotest bodies in space, are deduced from observations on the motion of bodies upon the surface of the earth and taking the facts above adverted to, which seem to indicate a state of quiescence or an inappreciable change during the last two thousand years, we must go back far beyond the deluge for the most recent of geological changes. But the reasoning is delusive; the physical constitution of the globe has suffered from repeated convulsions: the energies of Nature have been exerted in paroxysms, succeeding intervals of repose, and not in uniform and constant efforts. It was no security to the inhabitants of Herculaneum, who might thus have reasoned, that Vesuvius had been dormant from the earliest times to which tradition reached, nor is the absence of the dis

*

* Vesuvius from the period of the colonization of Italy by the Greeks, until the year 79 after Christ, had betrayed no symptoms

turbing forces in our own times and country, any proof that they may not have acted with great intensity in this part of the world at remote periods. Upon this rock Mr. Lyell splits, and here all his contemporaries leave him. Everything, he argues, indicates the constancy and invariability of the operations of Nature. Semper eadem is his motto, applied to her energies. An earthquake raises the coast of Chili five feet once in a century, four thousand such shocks may have lifted up the Andes, in the short space of four hundred thousand years! Why should Nature be " prodigal of her efforts and parsimonious of time?” *

But to return from this digression. Having briefly examined the operations of existing causes upon the earth's surface, and enquired into the physical events of contemporary and remote periods within the limits of the present state of things-events which have happened from the early period, when man and the present species of animals first became tenants of the earth, down to the occurrences recorded in history, or witnessed in our own times, we shall be prepared to enter upon the second and most important division of our subject, the stratified masses, to which we alluded in the outset, as constituting the superstructure of the globe-of which indeed all the changes we have hitherto passed in review before us, are only modifications-the mere effect, as it were, of time and accident upon the great edifice which

of its volcanic character, when after several earthquakes, its fires broke out with tremendous fury, and this celebrated city was inhumed by the ejected matter.

Lyell.-Principles of Geology.

Nature has reared. In this inquiry, history and tradition cease to aid us. No longer circumscribed by these, we must push forward into the great ocean of Time, and explore by the light of analogy the new world that lies before us.

STRATIFIED ROCKS.

OUR observations have hitherto been confined to the earth's surface, we have now to penetrate into its interior, to examine the monuments of past ages which Nature has imbedded in the solid masonry of the vast superstructure of the globe, as if to supply the chronologist or historian in after times, with dates and facts for its history, and preserve a record of events which would have been lost in the oblivious stream of time; in the same manner as in great works of architecture, coins, medals, and inscriptions, are placed in some indestructible portion of the building, in order that posterity may identify the period and circumstances of its erection, should all other records be lost. As we have before seen, Nature has not piled Pelion upon Ossa, or Ossa upon Pelion indiscriminately, as we might from superficial observation infer, nor has she reared a rude edifice of unshapen materials like the Cyclopean masonry, but throughout the great fabric of the earth has preserved a symmetrical arrangement and a unity of design; and in no portion of her work has she omitted to enclose some memorial of the circumstances and events of the period when it was produced.

The principal agent employed in the formation of

or

the stratified masses, appears to have been the ocean, other large bodies of water, in which the materials of the rocky strata have been suspended and quietly deposited, and the innumerable inhabitants of that element, whose remains form in many cases a considerable portion of the consolidated substance, lived and died. But this sedimentary process has not gone on uniformly from the beginning of time: the ocean has not always continued to deposit layer upon layer of earthy matter; its operations have been interrupted and for a time suspended, and again renewed under different circumstances, by convulsions in the interior of the earth, or changes upon its surface. Thus after a long series of ages, during which it may have deposited an immense mass of calcareous matter, the bed is perhaps upheaved, the sea is dispossessed of its dominion, and land animals and plants flourish on the oozy mass, where shells and fishes had before luxuriated.

It is this alternation, this succession of distinct operations, which has produced the series of stratified masses, which it is now our business to examine, and an enquiry attended with more interesting results never occupied the mind of man. For we soon discover that it is not merely the inorganic matter composing the earth's crust which has been remodelled in these geological changes, but that the animated creation has experienced still greater mutations, many species of animals being entombed in the strata which no longer exist upon the earth. Both sea and land appear to have been peopled with distinct races of inhabitants at successive periods, as every formation contains the remains of organic beings peculiar to itself. These organic relics