when we try to ascend to the act which has breathed the breath of life into generation after generation: and we find that even if our philosophy is allowed to burst the barriers of time, and to summon to its aid the energies of the elemental world, it is still unable to touch even the skirts of the garment of creative power which envelopes the Supreme Being.

With this striking exception, we may assert, with our author and other geologists, that all the facts of geological observation are of the same kind as those which occur in the common history of the world. The question then comes before us,-are the extent and the circumstances of the geological phenomena of the same order as those of which the evidence has thus been collected? Have the changes which lead us from one geological state to another been, on a long average, uniform in their intensity, or have they consisted of epochs of paroxysmal and catastrophic action, interposed between periods of comparative tranquillity?

These two opinions will probably for some time divide the geological world into two sects, which may perhaps be designated as the Uniformitarians and the Catastrophists. The latter has undoubtedly been of late the prevalent doctrine, and we conceive that Mr. Lyell will find it a harder task than he appears to contemplate to overturn this established belief. Indeed, we think it ought to be so. It seems to us somewhat rash to suppose, as the uniformitarian does, that the information which we at present possess concerning the course of physical occurrences, affecting the earth and its inhabitants, is sufficient to enable us to construct classifications, which shall include all that is past under the categories of the present. Limited as our knowledge is in time, in space, in kind, it would be very wonderful if it should have suggested to us all the laws and causes by which the natural history of the globe, viewed on the largest scale, is influenced-it would be strange, if it should not even have left us ignorant of some of the most important of the agents which, since the beginning of time, have been in action; of something, in short, which may manifest itself in great and distant catastrophes. When we find that such events as the first placing of man upon the earth, and the successive creation of vast numbers of genera and species, are proved to have occurred within assignable geological epochs, it seems to us most natural to suppose, that mechanical operations also have taken place, as different from what now goes on in the inorganic world, as the facts just mentioned are from what we trace in organic nature. But we will not at present proceed with this discussion.

If our geologists now resume the character of general theorists, which for some time they have in a great measure laid aside,

they

they will, it is hoped, proceed more temperately and cautiously than in former days, when the Neptunians and Plutonians alike attempted to pass, at a single rush, through all the varieties of successive formations to the first origin of things. The new race of speculators, at least the most intelligent and best informed of them, will probably now be content to work their way back, step by step; they will, we conceive, endeavour to make out, in the first place, the history of those strata which are uppermost and come nearest to our own time; they will study primarily the tertiary formations, those, namely, which lie above the chalk, and which, among their organic contents, include species not distinguishable from those now alive. By this path of investigation alone can they hope to ascend to the higher and more remote ages of geological antiquity. Among the events which this science has to deal with, the nearest are separated from us by intervals of overwhelming magnitude, the simplest are complicated with almost innumerable circumstances. Except these cases be first steadily and exactly considered, all expectation of secure and permanent advance in our speculative knowledge is visionary and futile.

The supercretaceous groups of strata, which thus may be expected to provide us with the best materials for sound theory, are fortunately very extensive and various in Europe, and have been recently studied with great devotion of zeal and attention. There is, indeed, something very striking in the view which these strata present to us of the vast changes of sea and land, of animal and vegetable life, which have taken place since the chalk was deposited. These changes, though probably occupying almost countless ages, must be considered as, geologically speaking, modern, because the resulting collection of fossils all of them offer some, and several of them many, species, identical with those which now live; while, in the strata from the chalk downwards, no such cases have yet been shown to occur. Mr. Lyell has given a very interesting map, principally founded on that of Dr. Boué, by which it appears, that a small part of Europe only has escaped being submerged at one time or other during this period.

The evidence of this fact, as applicable to different parts of Europe, has been gradually acccumulating upon us. The cele brated description of the strata of the neighbourhood of Paris, published in 1811 by Cuvier and Brogniart, gave the first impulse to this research. That district was shown to have been at certain epochs a portion of the sea,-at others a fresh-water lake, or dry land; and though the regular and distinct succession of these conditions has been proved by M. Constant Prevost

to

to have been too hastily assumed, the general facts of the case of the fossils of the Isle of Wight to those of Paris; and the connexion of the two districts has been recently still further established by Mr. Pratt, who discovered in the English locality some of the teeth of the French anaplotherium and palæotherium. Among the movements to which this part of the world has been subjected during the tertiary period, we trace not only that which has set on edge a vast range of the chalk in the Isle of Wight, but also the elevation of the subjacent sands and clays into a vast mound or saddle, extending from Salisbury Plain to Hastings, and separating the basins, originally one only, of London and Hants; for this operation, according to Dr. Buckland, took place after the deposition of the London clay. The southward of France, from Bourdeaux to the foot of the Pyrenees, contains in like manner evidence of having been covered by the waters of the postcretaceous times. The fresh-water deposits of Provence, which have been examined, among other persons, by. Professor Lyell and the present distinguished President of the Geological Society, Mr. Murchison, contain also a variety of curious remains of a similar period, among which occur many winged insects and spiders. Some deposits in the central parts of France have an additional interest, inasmuch as they are associated with the lava streams from extinct volcanoes which cover a large portion of that country, and thus give us in some measure the geological date of those eruptions. In Poland and in Russia also tertiary beds are found extensively distributed. A large addition to our knowledge on this subject will shortly be made by the publication of the labours of Messrs. Sedgwick and Murchison. These gentlemen have examined a wide range of deposits formed in an ocean which formerly washed the feet of the Eastern Alps; and they have been led to the conviction, that the last elevation of this chain, which lifted the plains of Bavaria above the sea, and separated the valleys of the Rhine and the Danube, took place after the tertiary strata of Switzerland were formed. The last mentioned of these writers has shown that the beds of Oeningen, near Constance, already famous as having supplied the aquatic Salamander (homo diluvii testis of Scheuchzer), and many remarkable fossils, belong to the time when there was a lake and dry land in that district. The same geologist has further had the joyous recollections of his earlier life revived by viewing and digging out of that locality a fine fossil fox, which was associated with a very perfect tortoise of a species not now living, but approaching nearest to the chelydra serpentina, or snapping tortoise of the North American lakes.

The most interesting formations, perhaps, with regard to our theoretical

theoretical views, are the subappenine strata of Italy; of which Mr. Lyell has so well illustrated both the natural and literary history. In Britain, besides the more southerly tertiary basins, we have evidence of the former subaqueous condition of the coasts of Norfolk and Suffolk in the crag' of those districts, so well known for the beauty and multitude of its fossils. And very recently it has been proved, that both the eastern and western shores of the northern division of England have formed part of the bed of the ocean within periods which, though far beyond the range of history, and probably before the creation of man, are, geologically speaking, modern.

Undoubtedly the tendency of opinion among geologists of late has been to consider these changes, not as the effect of any universal disturbance of the earth's surface, but as the results of a series of partial elevations and depressions, which have, at successive periods, affected various patches and strips of the earth, changing sea into land and land into sea, yet probably not submerging the highest portions of the dry land, nor obliterating the whole, or even the greatest part, of the existing continents and shores. That these great oscillations of the solid materials of the earth were not attended with a complete destruction of the then existing races of animals, appears to be proved by the occurrence, in the strata which attest these changes, of an abundance of species which still live, and which therefore, it is most natural to suppose, have been continuously propagated from that time to this. The appearance, among these assemblages of animals, of species undiscoverable in the previous state of the earth is, as we have already said, a fact which seems to lead us at once to au act of creation. But supposing new races to be thus placed upon the earth, provided with the means of subsistence and reproduction, we should expect that the progress of their numbers and well-being, and the fortunes of their struggles with external impediments, must depend on causes such as determine the condition of different families of animals in the present state of the world. Hence their groups and localities, and the geographical distribution and association of various species at each period of the earth's history, must probably be governed by the same laws as those which now prevail in similar phenomena at the earth's surface. This consideration places geology in contact with natural history and physiology, over a wide and almost indefinite extent. Without at present entering more at large into the-field thus opened, we shall point out, very briefly, two topics thus suggested, as subjects where the most extensive and comprehensive knowledge of the present is requisite to throw light upon the events of the past, as recorded in the organic fossils of the globe.

No

No fact is more remarkable, among those which have been brought into a clear and prominent light by the researches and comparisons of modern naturalists, than the division of the surface of the globe into distinct provinces, with reference to the distribution of animal and vegetable families. The plants and animals inhabiting each part of the globe are, no doubt, determined and limited by climate, soil, and many other physical conditions of existence. But, besides these causes, the influence of which is immediate and readily apprehended, some others, unknown and remote, but not less certain, have given to different districts, under the same circumstances of latitude and temperature, groups of species altogether different and distinct. Thus, in the flora of St. Helena, out of sixty-five native species, there are only two or three which are to be found in any other part of the globe. And this is not only the case where the communication is interrupted by the ocean; for, in an unbroken continent, if we take wide spaces, we find these invisible boundary lines to exist. There is found one assemblage of species in China, another in the countries bordering the Black Sea and the Caspian, a third in those surrounding the Mediterranean, a fourth in the great platforms of Siberia and Tartary. There are no indigenous quadrupeds common to the old and the new world. The elephant, the rhinoceros, the hippopotamus, the camelopard, the camel, the dromedary, the buffalo, the horse, the ass, the lion, the tiger, the ape, the baboon, are nowhere to be found on the American continent; their places were occupied by species sometimes analogous, but in all cases different, the tapir, the lama, the peccary, the jaguar, the couguar, the agouti, the paca, the coati, and the sloth. Similar demarcations, no doubt, prevail among the submarine vegetation and the races of marine animals. When, therefore, in a succeeding stage of the earth's history, these creatures come under our notice as geological subjects,-when Proteus has driven his cattle to visit the mountains and left them there, we may expect to find a similar distribution of distinct, though contemporaneous, organic remains. Hence, in establishing the synchronous origin of beds in remote situations, we are to expect to find, not an exact and rigorous identity of the co-existing species of all localities, but such a resemblance of the groups of species to each other as we find to obtain in the corresponding animal and vegetable provinces of the existing world. The application of this to the observed organic phenomena of the best characterised formations, would shew that this consideration is one of great practical value and utility to the geologist.

Again, the laws of the diffusion of the species of plants and animals are also of considerable interest. If we suppose, amid

the