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wings, terminated by long hooks like the curved claw on the bat's tumb; and their bodies and tail approximate to those of common mammalia. Dr Buckland conjectures that the Pterodactyle had also the power of swimming, like the vampyre bat of the island of Bonin.

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Next to the flying Saurians our author places the gigantic terrestrial Saurians-the megalosaurus and the iguanodon. The genus megalosaurus was established by Dr Buckland in 1824, from specimens found in the Oolitic slate of Stonesfield, near Oxford. Cuvier conceives it to have been an enormous reptile, measuring from forty to fifty feet in length, and partaking of the structure of the crocodile and monitor. The form of its teeth shows it to have been in a high degree carnivorous, and it is supposed to have fed on smaller reptiles,-such as crocodiles and tortoises, whose remains are found in abundance in the same strata. The most important part of this land lizard yet found, is a fragment of the lower jaw, containing many teeth, whose mechanism combines the properties of the knife, the sabre, and the saw.

The genus Iguanodon, or the gigantic terrestrial Saurian, we owe to the indefatigable labours of Mr Mantell, who discovered its insulated bones in the Wealden freshwater formation of the South of England. So lately as 1834, a very large part of the skeleton of this animal has been found in more recent strata in the quarries of Kentish Rag near Maidstone. This skeleton is now in Mr Mantell's museum, and confirms nearly all his deductions from the insulated bones he had previously found. From the analogy between this herbivorous animal, and the modern iguana, he has computed the dimensions of the iguanodon; and found its total length to be seventy feet, its tail fifty-two and a half feet long, and its body fourteen and a half feet round.

Passing over the amphibious saurians allied to crocodiles, which do not differ greatly from existing genera, we come to the fossil tortoises or testudinata, which have acquired special honour among fossil animals, by having left the traces of their footsteps distinctly imprinted on the solid rock. This curious discovery was made by Dr Henry Duncan of Ruthwell, who observed them on sandstone in the quarry of Corncockle muir in Dumfries-shire; and similar impressions have been recently observed in several quarries of grey sandstone at the village of Hessberg, near Hildburghausen, in Saxony. The specimens discovered by, Dr Duncan have been carefully preserved by him, and placed in the summer-house of his garden, where we have had the good fortune of seeing them. The beauty and distinctness of the footsteps are poorly represented in the best engravings, or even in the plaster casts we have

by our two distinguished countrymen, the Rev. Mr Conybeare and Mr de la Beche. About five or six species of this genus have been discovered, some of which had attained a prodigious size and length; but the Plesiosaurus dolichodeiros, discovered in the lias of Lyme Regis in 1823, is the best known and the most remarkable. Cuvier might well observe that that animal was the most heteroclite, and the one that deserved most the ' name of a monster,'-which, united to the head of a lizard, the teeth of a crocodile, a swan neck of enormous length, like the body of a serpent, the trunk and tail of an ordinary quadruped, the ribs of a cameleon, and the paddle legs of a whale.

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The last of the marine Saurians described by Dr Buckland, is the Mososaurus or great animal of Maestricht. A head of this animal, almost perfect, was discovered near that city in 1780, and though it had baffled every naturalist, Cuvier was able, from the examination of the jaws and teeth alone, and even from a single tooth, and before he had seen a single vertebra or a bone of any of its extremities, to announce the character of the entire skeleton. Adrian Camper, indeed, had first suggested, but Cuvier had the honour of demonstrating, that it was a gigantic marine reptile, nearly allied to the monitors,-a race of lizards which frequent the marshes and the banks of rivers in tropical climates. It has 133 vertebræ, and instead of legs, four large paddles like the whale. Hence it seems to have lived entirely in water, and ' though it was of such vast proportions, compared with the living genera of these families, it formed a link intermediate between the 'monitors and the iguanas. However strange it may appear to 'find its dimensions so much exceeding those of any existing lizard, or to find marine genera in the order of the Saurians, in which there exists at this time no species capable of living in 'the sea, it is scarcely less strange than the analogous deviations in the megalosaurus and iguanodon, which afford examples of 'still greater expansion of the type of the monitor and iguana ' into colossal forms adapted to move upon the land.'

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Anomalous as the marine Saurians are, the flying Saurians are still more so. Cuvier considers this genus, to which he has given the name of Pterodactyle, as the most extraordinary of all the beings that have come under his notice; and as that which, if we saw alive, would appear most unlike to any thing that nature presents to us. Eight species, varying from the size of a snipe to that of a cormorant, have been discovered. Externally, the Pterodactyle resembles our bats and vampyres. Its head and neck is like that of a bird. Its wings have the proportion and form of those of bats, and they have fingers projecting from these

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'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 precisely as I had arranged them, before my conjectures were vé'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.'

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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

tory of past ages of creation. We find successive stages marked by varying forms of animal and vegetable life, and these generally differ more and more widely from existing species as we go further downwards into the receptacles of the wreck of more ancient creations.

Besides the more obvious remains of testacea and of larger animals, minute examination discloses occasionally prodigious accumulations of microscopic shells that surprise us no less by their abundance than their extreme minuteness; the mode in which they are sometimes crowded together may be estimated from the fact that Soldani collected from less than an ounce and a half of stone found in the hills of Casciana, in Tuscany, 10,454 microscopic chambered shells.

Of several species of these shells, four or five hundred weigh but a single grain; of one species he calculates that a thousand individuals would scarcely weigh one grain.'

Extraordinary as these phenomena must appear, the recent discoveries of Ehrenberg, made since the publication of Dr Buckland's work, are still more marvellous and instructive. This eminent naturalist, whose discoveries respecting the existing infusorial animals we have already noticed, has discovered fossil animalcules, or infusorial organic remains; and not only has he discovered their existence by the microscope, but he has found that they form extensive strata of tripoli, or poleschiefer (polishing slate) at Franzenbad in Bohemia,-a substance supposed to have been formed from sediment of fine volcanic ashes in quiet waters. These animals belong to the genus Baccillaria, and inhabit siliceous shells, the accumulation of which form the strata of polishing slate. The size of a single individual of these animalcules is about 1-288th of a line, or the 3400th part of an inch. In the polishing slate from Bilin, in which there seems no extraneous matter, and no vacuities, a cubic line contains, in round numbers, twenty-three millions of these animals, and a cubic inch FORTY-ONE THOUSAND MILLIONS of them. The weight of a cubic inch of the tripoli which contains them is 270 grains. Hence there are 187 millions of these animalcules in a single grain; or the siliceous coat of one of these animals is the 18 millionth part of a grain!

Since this strange discovery was made, Mr Ehrenberg has detected the same fossil animals in the semiopal, which is found along with the polishing slate in the tertiary strata of Bilin,— in the chalk flints, and even in the semiopal or NOBLE OPAL of the porphyritick rocks. What a singular application does this fact exhibit of the remains of the ancient world! While our habitations are sometimes built of the solid aggregate of millions of miscroscopic shells,-while, as we have seen, our apartments are heated and lighted with the wreck of mighty forests that

covered the primeval valleys,-the chaplet of beauty shines with the very sepulchres in which millions of animals are entombed! Thus has death become the handmaid and the ornament of life. Would that it were also its instructor and its guide!

Hitherto Dr Buckland has considered only those cases in which the remains of animals that died a natural death have been preserved by the processes of slow and gradual accumulations.' He now proceeds to the highly interesting phenomena which prove that animals have been destroyed by some great and sudden cause. In our own day, such phenomena are not uncommon, and arise from an excessive admixture of mud with the waters of the sea during extraordinary tempests; from a sudden increase or diminution of temperature; from the irruption of salt water into fresh water lakes and estuaries; or from the sudden occupation of a part of the sea by a body of fresh water,-from unusual land floods, or the bursting of a lake. M. Agassiz informs us, that thousands of barbel were destroyed in the river Glat by a diminution of temperature of fifteen degrees.

The effects of these destroying causes are exhibited in a more interesting manner in the phenomena of organic remains. The fishes at Monte Bolca must have died suddenly, and been speedily buried in the calcareous sediment then in the course of deposition, and to the strata of which their skeletons lie parrallel. At Torre D'Orlando an entire shoal of the genus, Tetragonolepis, seems to have been destroyed at once either by some noxious impregnation of the water, or by an excess of heat. The fossil fishes of the cupriferous slate at Mansfeldt have a distorted position, as if writhing in the agonies of death,-maintaining the attitude of the rigid stage which immediately succeeds to death. To these remarkable facts Dr Buckland adds, in a subsequent chapter, a remarkable case of the cuttle-fish, which must have died suddenly and been quickly buried in the existing sediment. This conclusion is deduced from the fact, that these animals discharge the black fluid from their ink-bags in the moment of alarm; and that the fossil ink-bags are full of this fluid in a state of the most perfect preservation.

Dr. Buckland concludes his general views on the subject of fossil remains with an interesting chapter on the advantages which the herbivorous races derive from those that are carnivorous. Furnished with organs for seizing and destroying their prey, it cannot be doubted that this was the function for which they were designed. The destruction of animal life cannot be regarded as inconsistent with that general law of benevolence by which the greatest amount of enjoyment is secured to the greatest num

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