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tiles possess only from three to eight cervical vertebræ; birds approaching in this more nearly to the present species, but still falling greatly short of it, have from nine to twenty-three, the number being the greatest in the swan.'*

As the tail of the Plesiosaurus was short, and the neck long, its form was the converse of that of the Ichthyosaurus, and

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the views of Geoffroy de St. Hilaire,' says Mr. Conybeare, that nature, in the organization of the animal frame, has caused the sternal portion to shift its position along the vertebral column, seem to derive an important corroboration from the structure of this animal-; but it is remarkable that whereas the sternum holds a mean position in quadrupeds, and is thrown forwards in fishes, and backwards in birds, yet its position in this instance assimilates the Plesiosaurus less to fishes, though destined to move in the same element, than to birds, and exhibits at the same time a very wide departure from the type of the Saurian tribe.'

From the smallness of its head, its length of neck and shortness of tail, the Plesiosaurus, although it wanted a shell, was in some degree analogous in its general proportions to the tortoise and turtle-the latter it must have resembled in its motion.

That it was aquatic is evident from the form of its paddles; that it was marine is almost equally so from the remains with which it is universally associated; that it may have occasionally visited the shore, the resemblance of its extremities to those of the turtle may lead us to conjecture; its motion, however, must have been very awkward on land; its long neck must have impeded its progress through the water, presenting a striking contrast to the organization which so admirably fits the Ichthyosaurus to cut through the waves. May it not therefore be concluded (since, in addition to these circumstances, its respiration must have required frequent access of air) that it swam upon or near the surface, arching back its long neck like the swan, and occasionally darting it down at the fish which happened to float within its reach ?'-p. 388.

The habits here ascribed by Mr. Conybeare to the Plesiosaurus correspond very closely with those of the Testudo ferox, an inhabitant of Pensylvania, Carolina, and East Florida, whose neck when extended is nearly equal to its shell in length. It is described in Shaw's Zoology,t as fond of the muddy parts of rivers, hiding itself among the roots and leaves of water-plants, and thence springing on its prey, stretching out its neck to an incredible length, and seizing with celerity birds, &c. A restoration of the skeleton of the Plesiosaurus dolichodeirus, and another of that of the Ichthyosaurus communis, are given by Mr. Conybeare. We need say nothing of the discernment and anatomical skill with which these tasks have been performed; it is only necessary to mention that M. Cuvier, by adopting in almost every particular, and after a full examination, in his Fossil Os† Vol. iii. p. 63, 68.

Page 383.

teology,

teology, Mr. Conybeare's descriptions and plates, has paid our distinguished countryman the highest compliment that it was possible for him to receive.

In this volume is a notice, by Dr. Buckland, of the Megalosaurus of Stonesfield, another genus of fossil oviparous quadrupeds of prodigious magnitude. Although the known parts of the skeleton are at present very limited, it is ascertained to have belonged to the order of Saurians. From the dimensions of a thigh bone belonging to this animal, in the museum at Oxford, Cuvier, judging from the ordinary standard of the lizard family, assigned to the individual to which it belonged a length exceeding forty feet, and a bulk equal to an elephant seven feet high. But a femur twice as large has since been discovered, together with other bones of another of the same species, in the ferruginous sandstone of Tilgate Forest, near Cuckfield, in Sussex. This is preserved in the collection of Mr. Gideon Mantell, of Lewes.

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If,' says the Professor, the total length and height of animals were in proportion to the linear dimensions of their extremities, the beast in question would have equalled in height our largest elephants, and in length fallen but little short of the largest whales; but as the longitudinal growth of animals is not in so high a ratio, after making some deduction, we may calculate the length of this reptile from Cuckfield at from sixty to seventy feet.'

We ought not to omit, when speaking of the fossil reptiles found in Sussex, the Iguanodon, which, like the three former genera, has been first discovered in this county. Mr. Mantell, upon comparing the teeth with those of a recent Iguana in the College of Surgeons, satisfactorily ascertained its affinity to that animal; the teeth are remarkable for their serrated edges and the ridges on the vertical surface.* This reptile is supposed to have been sixty feet in length, to have been herbivorous, and probably to have inhabited fresh water; for the assemblage of organic remains in the strata that inclose it, afford almost unequivocal proofs of having been deposited in the estuary of a great river. The largest living species of crocodiles are said -sometimes to attain thirty feet in length, but they rarely exceed twenty. Huge reptiles now inhabit exclusively warmer latitudes; they are most abundant between the tropics; but in the northern hemisphere, both in North America and in Africa, they sometimes exceed this limit by ten or twelve degrees.

We cannot wonder that geologists have been suspected of a love for the marvellous, and that sceptics should be exceedingly

* Cuv. Oss. Foss. vol. v. part ii. p. 351.

Shaw, vol. iii. p. 186.

nu

numerous in this our island, although it is still as true as it was in the time of Trinculo, that if a strange beast' be exhibited here, there is not a holyday fool but would give a piece of silver.' Whether it be a giant or a dwarf, a natural or artificial deformity, a Chinese mermaid, or any creature born with more or less than its due proportion of members, it will not want admirers of a certain class. But there is also no country where so many persons can be found of inquiring mind and liberal education, and yet almost entirely ignorant even of the first elementary steps of natural history. If these are without skill in comparative anatomy, and are yet interested in the results of these osteological researches, we may remind them that a leaning on the side of credulity was deemed truly philosophical by Pliny-' nam mihi contuenti se persuasit Rerum Natura nihil incredibile existimare de eâ.* If any thing could justify,' says Cuvier, those hydras and other monsters whose figures are so often repeated in the monuments of the middle ages, it would incontestably be the Plesiosaurus.'t Yet we may confidently say of this creature, and of the Megalosaurus and Iguanodon, what Ariosto had the audacity to declare of his hyppo-griffin :

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'Non finzion d' incanto come il resto

Ma vero e natural si vedea questo.'

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The Pterodactyls, however, or flying lizards, described by Cuvier, recal still more forcibly to our recollection the winged dragons of fabulous legends. They might, perhaps, have been as inoffensive as the small flying reptile now found in Asia and Africa; but the size of some of them, their long jaws armed with sharp teeth, and the hooked nails of their claws, would render them truly terrific were they to revisit Christendom, now no longer under the shield of the Seven Champions. That we should find some fictitious animals of romance nearly realized, upon being suddenly admitted as it were to the creations of new worlds, will surprize none who are conversant with the laws of organic nature, and who have well considered the principles on which the charms of poetic fiction depend. In fabricating imaginary animals the license of fiction does not extend to extravagant violations of known analogies, but merely to the combination of parts and functions never yet seen to co-exist. It is not long since naturalists discovered in a living animal, the Ornithorhynchus of New Holland, the organization and habits not

Pliny, lib. xi. chap. 3.

+ Cuvier, Discours sur les Rev. p. 303.

1825.

Cuv. Oss. Fos. vol. ii. part ii. p. 358. 380.

Draco volans of Linn. See Shaw, vol. iii. p. 177.

only

only of different genera, but of three distinct classes of former systems, all united and blended together in one single individual;

To enter at large into the consideration of other classes of organic remains, or to examine in detail those described in the present volume, would be inconsistent with our present limits and scope. In the illustration of these objects, lithography has been successfully employed. This art, so strongly recommended by its surior cheapness, may exert a favourable influence on the future progress of science, and particularly on natural history, which has always been retarded by the unavoidable expense of engraving. The plates descriptive of the osteological structure of the large Reptiles we have been mentioning deserve especial commendation, as do the figures of plants discovered by Mr. Mantell in the same strata with the Iguanodon, near Cuckfield in Sussex. These remains consist partly of ferns, that numerous fossil genus, and partly of vegetables analogous to the genera Zamia and Cycas, now particularly characteristic of tropical regions. The plates of Orthoceræ from the islands of Lake Huron are also admirably executed in lithography. These chambered univalve shells, so interesting to the conchologist from the peculiar structure of the siphuncle, are described in a paper by Dr. Bigsby on the geology of part of North America bordering on Lake Huron. No recent species of Orthocera hitherto discovered exceeds half an inch in length; the fossil species both in Europe and America frequently attain the length of many feet. The only multilocular univalve Testacea of large dimensicus now existing are some species of Nautilus, and these are confined to tropical climates. The abundance therefore of Ammonites, Orthoceræ, and Nautili of great magnitude, in the strata of Europe and North America, is worthy of observation, as tending, in concurrence with other branches of organic remains, to confirm that striking deduction of geology, that the former temperature of the northern hemisphere was much higher than it is at present.

As the fossil species appear to be all, with very few exceptions, extinct, we reason only from analogy when we draw this conclusion, and we ought therefore to require a great accumulation of evidence, together with perfect harmony in the proofs. This question, concerning the former temperature of the globe, is extremely interesting, and it has so often been alluded to during our consideration of fossil animals and plants, that we shall lay before

*However great may be the expedience of a speedy reform in the nomenclature of natural history, we must not attempt it in this place. It may be as well, in compassion to the uninitiated, to inform them that, when Lamarck writes Orthocera, he means Orthoceras, and that, in the language now spoken by conchologists, Orthoceræ stands for Orthocerata.

our

our readers a concise view of the principal data on which the prevailing opinions of naturalists in regard to it are founded.

Remains of large herbivorous quadrupeds occur in the superficial gravel of Europe and North America, referable to genera now confined to warmer climates. Their number does not diminish as we proceed northwards, but, on the contrary, the greatest abundance has been found in Siberia, where the vegetation is now so scanty and buried for so long a time under the snow of a polar winter, that it is impossible to conceive how herds of elephants could ever have existed there, had the climate been always so severe as it is at present. Various oviparous quadrupeds, tortoises, turtles, crocodiles, and those gigantic Saurian animals, which engaged our attention in an earlier part of this essay, are distributed in profusion throughout the strata of every part of Europe, some even in the most recent formations above the chalk, and others in different parts of the series, down to the lias and the copper-slate of Thuringia inclusive. Nothing analogous to these classes of large reptiles exists at present in temperate

latitudes.

Univalve shells are said to predominate in number over bivalves throughout the secondary strata in Europe, as at present in tropical seas.* To the occurrence of large chambered univalve shells, and the conclusions to which they point, we need not again refer. Corals and other zoophytes are found at present to increase in size, in variety of species, and rapidity of growth, as we approach the equator. They form large reefs in intertropical seas, where their comminuted fragments constitute a considerable portion of the beach, and are remarkable for their tendency to consolidate, with other loose materials, into rock. Such a state of things must be supposed to have existed when the oolitic series and many other strata in Europe were deposited. But as we ascend towards the superior and more recent formations, which contain genera of shells more analogous to those now inhabiting our seas, fossil zoophytes become much rarer and inferior in size.

The above inferences are derived from so extensive a collection of facts, that the number of exceptions must be regarded as singularly small, and most of these are merely founded on analogy like the evidence on the other side. Remains of Cetaceous animals, for example, of a genus now exclusively tropical, have been discovered in a limestone in France, the calcaire grossière, with a species of another Cetaceous genus now peculiar to the frozen zone. A more remarkable exception occurs in the discovery of

*Defrance, Tab. des Corps Org. Foss. 51. 125. + Cuv. Discours sur les Rev. p. 313.

bones

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