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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, orinfusorial 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

ber of individuals. Life is a gift which the Creator dispenses with an equal hand to those on whom it is conferred. The amount of happiness which it brings seems to be in the inverse ratio of the time of its enjoyment; and the being that riots for a day in the light and heat of the sunbeam, would perhaps not exchange its ephemeral elysium for the protracted and often miserable centuries of an antediluvian existence. Nor does the manner in which that life is brought to a close at all affect the determinate quantity of its felicity. The religious feelings, and human sympathies, and secular interests which preside at the deathbed of man, impel us to watch with double care over sickness, and decrepitude, and age, and to protract to the last moment even the agonies by which we are appalled. In the world of instinct, however, where the affections have but a limited range, a quick and a violent death becomes the truest charity. The tiger is at once the doctor, the lawyer, the sexton, and the residuary legatee of the peaceful occupants of his native jungle.

But this law of destructive happiness is not confined, as Dr Buckland should have mentioned, to the irrational world. Though his species cannot boast of any lethal mechanism which combines, like the teeth of the Megalosaurus, the slaying power of the 'sabre, the knife, and the saw,' and cannot therefore charge their carnivorous deeds either upon their claws or their teeth, yet the history of man is written in the blood of his fellows, and feats of cruelty and violence emblazon the chronicle even of his amusements. In the battles of ambition, where bloodthirsty myrmidons pant for the destruction of their kind-in the enactment and toleration of sanguinary laws—in acts of ignorant and profligate legislation by which millions are starved and expatriated and in those nameless deeds of injustice and persecution by which power does slow execution upon its victims, we may match the most sanguinary acts of the most sanguinary age of carnivorous ascendency.

Dr Buckland is now brought, in virtue of his arrangement, to consider the proofs of design exhibited in the specific structures of fossil animals. He begins with the fossil mammalia, or those animals that give suck to their young; but as the greater number of the earliest fossil animals of this class differ in few essential points from their living representatives, he selects the two extinct genera of the Dinotherium and the Megatherium—the first, the largest of the terrestrial mammalia, and the second, the one that deviates most from the ordinary forms of animal life.

The remains of the Dinotherium occur most abundantly in

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Hesse-Darmstadt. Both Cuvier and Kaup calculate the size of the largest species, the Giganticum, to have been eighteen feet in length. Its shoulder-blade, resembling that of a mole, indicates an adaptation of the fore-leg to the purposes of digging. It differs from all other quadrupeds in carrying at the extremity of its lower jaw, which is twelve feet long, two enormous tusks, which Dr Buckland considers as instruments for raking and grubbing up the roots of large aquatic vegetables, combining the powers of the pickaxe with those of the horse-harrow. He conceives also that these tusks might be used to hook the head of the animal to the bank of a lake or river, where it might repose itself while floating on the water. Hence he regards it as a herbivorous aquatic quadruped, adapted to the lacustrine condition of the earth during the tertiary periods.

The Megatherium, which has been fully described by Cuvier, is a most extraordinary animal, nearly allied to the sloth, with the same apparent monstrosity, and many singular peculiarities of structure. An engraving, of which Dr Buckland has given a very beautiful one, is necessary to convey an idea of it; and as we cannot abridge our author's long and interesting account of its peculiar structure we must content ourselves with referring to the work itself.*

The gigantic character of these indwellers of the lakes have induced Dr Buckland to give them the precedence of the very old family of the Saurians; so that we must now go back to the early age of the secondary strata to contemplate the earth when inhabited by crocodiles and lizards of various forms, ⚫ and often of gigantic size; fitted to endure the turbulence and con'tinual convulsions of the unquiet surface of our infant world.' These strange animals were not only the principal occupants and the dreaded tyrants of the dry land, but they exercised a dominion also over the waters of the sea.

The name of Ichthyosaurus, or fish-lizard, has been given to

* Dr Buckland mentions, in a supplementary note, the discovery of a large fossil animal in the valley of the Markanda, in the Sivalic or sub-Himalayan range of hills between the Jumna and the Ganges. It exceeds in size the largest rhinoceros, and forms an important link between the Ruminantia and the Pachydermata. The head was found nearly entire; and more recently, Captain Cautley bas discovered a portion of the skeleton in another part of the hills. These last portions, however, seem to have been lost. Dr Falconer's and Captain Cautley's account of the Sivatherium, will be found in the London and Edinburgh Phil, Journal, for September and October, 1836, p. 193, 277.

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some of the most remarkable of these reptiles, which possess combinations of form and mechanical contrivances which are now dispersed through various classes and orders of existing 'animals, but are no longer united in the same genus.' In its general outline the Ichthyosaurus resembles the modern porpoise or grampus. It combines the snout of a porpoise, the teeth of a crocodile, the head of a lizard, the sternum of an ornithorynchus, with the paddles of a whale. It has a long and powerful tail, and the total length of some of the largest must have exceeded thirty feet.

The most extraordinary feature of this singular animal is the enormous magnitude of its eye; which is such, that in a skull of the Ichthyosaurus platyodon, in the collection of Mr Johnson at Bristol, the larger diameter of the orbital cavity is fourteen inches! The following are Dr Buckland's observations on this singular optical instrument:-

'From the quantity of light admitted in consequence of its prodigious size, it must have possessed very great powers of vision; we have also evidence that it had both microscopic and telescopic properties. We find on the front of the orbital cavity, in which this eye was lodged, a circular series of petrified thin bony plates, ranged around a central aperture, where once was placed the pupil; the form and thickness of each of these plates very much resembles that of the scales of an artichoke. In living animals these bony plates are fixed in the exterior or sclerotic coat of the eye, and vary its scope of action, by altering the convexity of the cornea; by their retraction they press forward the front of the eye, and convert it into a microscope; in resuming their position, when the eye is at rest, they convert it into a telescope.'

We have quoted this passage in order to enliven the monotony of our praise by a single note of censure; and in the hope also that Dr Buckland will remodel it in another edition. Even if the physiology of the passage were correct, we should object strongly to the statement that the eye of any animal which has the power of adjustment to different distances-and what animal has not this power?-possesses microscopic and telescopic properties. The general reader cannot fail to regard these properties as peculiarly belonging to the huge eye of the Ichthyosaurus, which Dr Buckland does not mean to insinuate. With regard to the use of the bony circle it is a most gratuitous hypothesis to make it the mechanism of adjustment to different distances. Even in the human eye, upon which we can make endless experiments, we know nothing of the mechanism of adjustment; and if Kepler, and Newton, and the most distinguished of their successors, aided with all the skill of the optician and the anatomist,

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