backwards the first term of the finite series of organic beings, and there still remains beyond this point an antecedent period, in which a state of total fusion pervaded the entire materials of the fundamental granite, and one universal mass of incandescent elements, wholly incompatible with any condition of life which can be shown to have ever existed, formed the entire substance of the globe.'

We come now to the transition rocks, in which strata of slate and shell alternate with slaty sandstone, limestone, and conglomerate rocks. These strata bear evidence of two remarkable facts. The conglomerate rocks exhibit the action of water in a state of violent motion, while the others contain both animal and vegetable organic remains. Among the animal remains are a few fishes, several families of mollusca, many of which are extinct; the remarkable extinct family of trilobites, belonging to the order of articulated animals; and a considerable number of the radiated animals. But the remains of fossil vegetables have a peculiar interest. Those which occur in the lower beds of the transition series are few in number, and principally marine; but in the upper beds we find prodigious accumulations of land plants, exhibiting to us the earliest vegetables which were reared upon our planet, and furnishing civilized man with the most valuable products of the mineral kindgdom.

The strata in which these vegetable remains have been collected together in such vast abundance, have been justly designated by the name of the carboniferous order, or great coal formation.

'Besides this coal, many strata of the carboniferous order contain subordinate beds of a rich argillaceous iron ore, which the near position of the coal renders easy of reduction to a metallic state; and this reduction is further facilitated by the proximity of limestone, which is requisite as a flux to separate the metal from the ore, and usually abounds in the lower region of the carboniferous strata.

"A formation that is at once the vehicle of two such valuable mineral productions as coal and iron, assumes a place of the first importance among the sources of benefit to mankind; and this benefit is the direct result of physical changes which affected the earth at those remote periods of time when the first forms of vegetable life appeared upon its surface.

The important uses of coal and iron, in administering to the supply of our daily wants, give to every individual amongst us, in almost every moment of our lives, a personal concern, of which but few are conscious, in the geological events of these very distant eras. We are all brought into immediate connexion with the vegetation that clothed the ancient earth, before one half of its actual surface had yet been formed. The trees of the primeval forests have not, like modern trees, undergone decay, yielding back their elements to the soil and atmosphere by which they had been nourished; but treasured up in subterranean store-houses, have been transformed into enduring beds of coal, which in these later

ages have become to man the sources of heat, and light, and health. My fire now burns with fuel, and my lamp is shining with the light of gas, derived from coal that has been buried for countless ages in the deep and dark recesses of the earth. We prepare our food, and maintain our forges and furnaces, and the power of our steam-engines, with the remains of plants of ancient forms and extinct species, which were swept from the earth ere the formation of the transition strata was completed. Our instruments of cutlery, the tools of our mechanics, and the countless machines which we construct, by the infinitely varied applications of iron, are derived from ore, for the most part coeval with or more ancient than the fuel by the aid of which we reduce it to its metallic state, and apply it to innumerable uses in the economy of human life.

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Thus, from the wreck of forests that waved upon the surface of the primeval lands, and from ferruginous mud that was lodged at the bottom of the primeval waters, we derive our chief supplies of coal and iron, those two fundamental elements of art and industry which contribute, more than any other mineral production of the earth, to increase the riches, and multiply the comforts, and ameliorate the condition of mankind.'

In treating of the secondary strata, which are composed of extensive beds of sand and sandstone, mixed occasionally with pebbles, and alternating with deposits of clay, and marl, and limestone, and deriving their materials from the detritus of primary and transition rocks, Dr Buckland considers them in two points of view-in their condition as dry land, destined to be the habitation of man; and in their previous state, while forming at the bottom of the waters, tenanted by innumerable organic beings, enjoying all the privileges of animal life.

'With regard to their adaptation to human uses, it may be generally stated, that the greater number of the most populous and highly civilized assemblages of mankind inhabit those portions of the earth which are composed of secondary and tertiary formations. Viewed, therefore, in their relations to that agricultural stage of human society, in which man becomes established in a settled habitation, and applies his industry to till the earth, we find in these formations which have been accumulated, in apparently accidental succession, an arrangement highly advantageous to the cultivators of their surface. The movements of the waters, by which the materials of strata have been transported to their present place, have caused them to be intermixed in such manner, and in such proportions, as are in various degrees favourable to the growth of the different vegetable productions which man requires for himself, and the domestic animals he has collected around him.

The process is obvious whereby even solid rocks are converted into soil fit for the maintenance of vegetation, by simple exposure to atmospheric agency; the disintegration produced by the vicissitudes of heat and cold, moisture and dryness, reduces the surface of almost all strata to a comminuted state of soil or mould, the fertility of which is usually in proportion to the compound nature of its ingredients.

The three principal materials of all strata are the earths of flint, clay,

and lime; each of these, taken singly, and in a state of purity, is comparatively barren; the admixture of a small proportion of clay give tenacity and fertility to sand, and the further addition of calcareous earth produces a soil highly valuable to the agriculturist; and where the natural proportions are not adjusted in the most beneficial manner, the facilities afforded by the frequent juxtaposition of lime, or marl, or gypsum, for the artificial improvement of those ingredients, add materially to the earth's capability of adaptation to the important office of producing food. Hence it happens, that the great corn fields, and the greatest population of the world, are placed on strata of the secondary and tertiary formations, or on their detritus, composing still more compound, and consequently more fertile diluvial and alluvial deposits.

Another advantage in the disposition of stratified rocks, consists in the fact that strata of lime-stone, sand, and sand-stone, which readily absorb water, alternate with beds of clay, or marl, which are impermeable to this most important fluid. All permeable strata receive rain water at their surface, whence it descends until it is arrested by an impermeable subjacent bed of clay, causing it to accumulate throughout the lower region of each porous stratum, and to form extensive reservoirs, the over-flowings of which on the sides of valleys, constitute the ordinary supply of springs and rivers. These reservoirs are not only occasional crevices and caverns, but the entire space of all the small interstices of these lower parts of each permeable stratum, which are beneath the level of the nearest flowing springs. Hence, if a well be sunk to the water-bearing level of any stratum, it forms a communication with a permanent subterranean sheet of water, affording plentiful supplies to the inhabitants of upland districts, which are above the level of natural springs.

A further benefit which man derives from the disposition of the mineral ingredients of the secondary strata, results from the extensive diffusion of muriate of soda, or common salt, throughout certain portions of these strata, especially those of the new red sand-stone formation. Had not the beneficent providence of the Creator laid up these stores of salt within the bowels of the earth, the distance of inland countries from the sea would have rendered this article of prime and daily necessity unattainable to a large proportion of mankind; but under the existing dispensation the presence of mineral salt, in strata which are dispersed generally over the interior of our continents and larger islands, is a source of health and daily enjoyment to the inhabitants of almost every region of

the earth.'

The condition of animal life, during the deposition of the secondary strata, presents many points of high interest. Although these strata contain the remains of animals belonging to all the four existing divisions of the animal kingdom, the earth was not yet adapted to the warm-blooded terrestrial mammalia. The only terrestrial mammalia which have been found in the secondary rocks, are the small marsupial quadrupeds allied to the opossum; but the peculiar feature of these strata, according to our author, is the prevalence of numerous and gigantic forms ' of saurian reptiles. Many of these were exclusively marine; ' others amphibious; others were terrestrial, ranging in savannahs

and jungles clothed with a tropical vegetation, or basking on the margins of estuaries, lakes, and rivers. Even the air was te'nanted with flying lizards, under the dragon form of Pterodactyles. The earth was probably at that time too much covered ' with water, and these portions of land which had emerged above 'the surface were too frequently agitated by earthquakes, inun⚫dations, and atmospherical irregularities, to be extensively occupied by any higher order of quadrupeds than reptiles.'

In treating of the strata of the tertiary rocks, Dr Buckland introduces us to a system of new phenomena presenting formations in which the fossil remains of plants and animals approach gradually to the species of the present day. The most interesting feature of the tertiary strata, and the discovery of which we owe to Cuvier, is, that these formations were produced by repeated irruptions of the sea, occasioning repeated alternations of marine deposits with those of fresh water. In studying these formations geologists have recognised at least four distinct periods in their order of succession, distinctly marked by the different proportions between the recent and the extinct species of shells which are found in them. Mr Lyell has indicated these periods by the names Eocene, Miocene, Older Pliocene, and Newer Pliocene. In the first of these divisions the proportion of the recent species of shells is only 3 per cent. In the second period it is 18 per cent. In the third it is from 35 to 50 per cent; and in the fourth it is from 90 to 95, the older species having now become almost extinct. Alternating with these four salt-water formations above the chalk, there is a fourfold series of other strata, containing fresh-water shells, and the remains of many terrestrial and aquatic quadrupeds.

It was in the examination of these fossil remains, found in the gypsum quarries of Montmartre, that Cuvier was led to the restoration of so many genera and species. After describing the manner in which the exuviæ of former worlds were accumulated in the cabinets of Paris, he gives the following memorable account of his researches. I at length found myself as if placed in a ' charnel-house, surrounded by mutilated fragments of many hun'dred skeletons of more than twenty kinds of animals, piled con'fusedly around me. The task assigned me was to restore them 'all to their original positions. At the voice of comparative an'atomy, every bone and fragment of a bone resumed its place. I 'cannot find words to express the pleasure I experienced in see'ing as I discovered one character, how all the consequences ' which I predicted from it were successively confirmed; the feet 'were found in accordance with the characters announced by the

'teeth; the teeth in harmony with those indicated beforehand by the feet. The bones of the legs and thighs, and every con⚫necting portion of the extremities were found set together pre'cisely as I had arranged them, before my conjectures were ve'rified by the discovery of the parts entire. In short, each species ' was, as it were, reconstructed from a single one of its compon'ent elements.'

Another remarkable feature of the first period of the tertiary formation in various parts of Europe, is the frequent intrusion of volcanic rocks; and hence, we may reasonably conjecture, that from the convulsions and changes of level which such a cause must have produced, different portions of the same district have become alternately the receptacles of salt and of fresh water.

This general view of the inorganic world, Dr Buckland concludes with an interesting chapter on the relation of the earth and its inhabitants to man;' and it gives us great pleasure to observe, that he has been led to that view of final causes which we had given in a previous review of another' Bridgewater • Treatise.'

Dr Buckland now proceeds to the most important and popular branch of his subject,--to give a description of the most interesting fossil organic remains, and to show that the extinct species of plants and animals which formerly occupied our planet, display, even in their fragments and relics, the same marks of wisdom and design which have been universally recognised in the existing species of organized beings.

After giving some account of the supposed cases of fossil human bones, and establishing the remarkable fact of the total ' absence of any vestiges of the human species throughout the entire series of geological formation,' our author passes to the general history of fossil organic remains:—

It is marvellous that mankind should have gone on for so many centuries in ignorance of the fact, which is now so fully demonstrated, that no small part of the present surface of the earth is derived from the remains of animals that constituted the population of ancient seas. Many extensive plains and massive mountains form, as it were, the great charnel-houses of preceding generations, in which the petrified exuvia of extinct races of animals and vegetables are piled into stupendous monuments of the operations of life and death, during almost immeasurable periods of past time. "At the sight of a spectacle," says Cuvier, "so imposing, so terrible as that of the wreck of animal life, forming almost the entire soil on which we tread, it is difficult to restrain the imagination from hazarding some conjectures as to the causes by which such great effects have been produced.' The deeper we descend into the strata of the earth, the higher do we ascend into the archæological his