Chapter 5

[12]Greek—megas, great;sauros, lizard.

No entire skeleton of the Megalosaur has ever been found, but there was enough material to enable Dr. Buckland, Professor Owen, and Professor Phillips to form a very fair idea of its general structure. It should be mentioned here that Dr. Mantell, the enthusiastic geologist to whose labours palæontologists are greatly indebted, had previously discovered similar teeth and bones in the Wealden strata of Tilgate Forest. Sherborne, in Dorset, is another locality which has yielded a fine specimen of parts of both jaws with teeth. A cast of this may be seen in the geological collection at South Kensington. It was found in the Inferior Oolite (Wall-case IV.); the original specimen lies in the museum of Sherborne College. Remains of Megalosaurus have also been found at the following places: Lyme-Regis and Watchet (in the Lias); near Bridport (in Inferior Oolite); Enslow Bridge (upper part of the Great Oolite and Forest Marble Beds); Weymouth (in Oxford Clay); Cowley and Dry Sandford (in the Coral Rag); Malton in Yorkshire (in Coralline Oolite); also in Normandy. They have also been found in Wealden strata.

The portion of a lower jaw in the Oxford Museum is twelve inches long, with a row of nine teeth, or sockets for teeth. The structure of the teeth leaves no doubt as to the carnivorous habits of the creature. With a length of perhaps thirty feet, capable of free and rapid movement on land, with strong hind limbs, short head, with long pointed teeth, and formidable claws to its feet, the Megalosaur must have been without a rival among the carnivorous reptiles on this side of the world. It probably walked for the most part on its hind legs, as depicted in our illustration, and Professors Huxley and Owen, on examining the bones in the Oxford Museum, were much impressed with the bird-like character of some parts of the skeleton, showing an approach to the ostrich type. The form of the teeth, as pointed out by Dr. Buckland, exhibits a remarkable combination of contrivances. When young and first protruding above the gum, the apex of the tooth presented a double cutting edge of serrated enamel; but as it advanced in growth its direction was turned backwards in the form of a pruning knife, and the enamelled sawing edge was continued downwards to the base of the inner and cutting side, but became thicker on the other side, obtaining additional strength when it was no longer needed as a cutting instrument (Fig. 12).

Fig. 12.—Lower jaw-bone of Megalosaurus, with teeth.

The genus Megalosaurus—now rendered classic through the labours of Professors Buckland, Phillips, and Owen—may be regarded as the type of the carnivorous Dinosaurs; and it affords an excellent and instructive instance of the gradual restoration of the skeleton of a new monster from more or less fragmentary remains. Certain very excusable errors were at first made in therestoration, but these have since been rectified by a comparison with the allied American forms, such as Allosaurus, of which nearly entire skeletons have of late been discovered in strata of Jurassic age—in fact, the same rock in Colorado as that in which the huge Atlantosaurus bones lay hid. The accompanying woodcut (Fig. 13) shows how the skeleton has been restored in the light of these later discoveries of Professor Marsh. The large bones of the limbs of these formidable flesh-eating monsters were hollow, and many of the vertebræ, as well as some of those of the feet, contained cavities, or were otherwise lightened in order to give the creature a greater power of rapid movement.

Fig. 13.—Skeleton of Megalosaurus, restored. (After Meyer.)

It is not very difficult to imagine a Megalosaur lying in wait for his prey (perhaps a slender, harmless little mammal of the ant-eater type) with his hind limbs bent under his body, so as to bring the heels to the ground, and then with one terrific bound from those long legs springing on to the prey, and holding the mammal tight in its clawed fore limbs, as a cat might hold a mouse. Then the sabre-like teeth would be brought into action by the powerful jaws, and soon the flesh and bones of the victim would be gone! (SeePlate VI.)

Plate VI.

A CARNIVOROUS DINOSAUR, MEGALOSAURUS BUCKLANDI.Length about 25 feet.

As we remarked before, the carnivorous Dinosaurs were the lions and tigers of the Mesozoic era, and, what with small mammals and numerous reptiles of those days, it would seem that they were not limited in their choice of diet.

It is a question not yet decided whether Dinosaurs laid eggs as most modern reptiles do, or were viviparous like quadrupeds; but Professor Marsh thinks there are reasons for the latter supposition.

During the early part of the Mesozoic era, at the period known as the Triassic (New Red Sandstone), Dinosaurs flourished vigorously in America, developing a great variety of forms and sizes. Although but few of their bones have as yet been discovered in those rocks, they have left behind unmistakable evidence of their presence in the well-known footprints and other impressions upon the shores of the waters which they frequented.[13]The Triassic Sandstone of the Connecticut Valley has long been famous for its fossil footprints, especially the so-called “bird-tracks,” which are generally supposed to have been made by birds, the tracks of which they certainly appear to resemble. But a careful investigation of nearly all the specimens yet discovered has convinced Professor Marsh that these fossil impressions were not made by birds (seeFig. 14). Most of the three-toed tracks, he thinks, were made by Dinosaurs, who usually walked upon their hind feet alone, and only occasionally put to the ground their small fore limbs. He has detected impressions of the latter in connection with nearly all the larger tracks of the hind limbs. These double impressions are just such as Dinosaurs would make; and, since the only characteristic bones yet found in the same rocks belong to this order of reptiles, it is but fair to attribute all these footprints to Dinosaurs, even where no impressions of fore feet have been detected,untilsome evidence of birds is forthcoming. The size of some of these impressions, aswell as the length of stride they indicate, is against the idea of their having been made by birds. Some of them, for instance, are twenty inches in length, and four or five feet apart! The foot of the African ostrich is but ten inches long, so we must fall back on the Dinosaurs for an explanation. However, it is quite possible that some of the smaller impressions were made by birds.

[13]Since the above was written, Professor Marsh has described, inThe American Journal of Sciencefor June, 1892, several more or less complete skeletons of Triassic Dinosaurs, lately found, and now in the Yale College Museum. This is an important discovery.

Fig. 14.—Portion of a slab of New Red Sandstone, from Turner’s Falls, Massachusetts, U.S., covered with numerous tracks, probably of Dinosaurs. This specimen is now in the Natural History Museum. The separate tracks are indicated by the numbers. (After Hitchcock.)

There is at South Kensington a fine series of these and other specimens of fossil footprints (Gallery No. XI., Wall-cases 8-10). The surface of one large slab in the geological collection is eightfeet by six feet, and bears upwards of seventy distinct impressions disposed in several tracks, as shown inFig. 14. The lines were added by Dr. Hitchcock, who has published full descriptions in order to show the direction and disposition of the tracks.

Fig. 15.—Portion of a slab, with tracks. (After Hitchcock.)

In a presidential address to the Geological Society, Sir Charles Lyell, speaking of the Connecticut Sandstone and its impressions, said, "When I first examined these strata of slate and sandstone near Jersey City, in company with Mr. Redfield, I saw at once from the ripple-marked surface of the slabs, from the casts of cracks, the marks of rain-drops, and the embedded fragments of drift-wood, that these beds had been formed precisely under circumstances most favourable for the reception of impressions of the feet of animals walking between high and low water. In the prolongation of the same beds in the Valley of Connecticut, there have been found, according to Professor Hitchcock, the footprints of no less than thirty-two species of bipeds, and twelve of quadrupeds. They have been observed in more than twenty localities, which are scattered over an area of nearly eighty miles from northto south, in the States of Massachusetts and Connecticut. After visiting several of these places, I entertained no doubt that the sand and mud were deposited on an area which was slowly subsiding all the while, so that at some points a thickness of more than a thousand feet of superimposed strata had accumulated in very shallow water, the footprints being repeated at various intervals on the surface of the mud throughout the entire series of superimposed beds." When Sir Charles Lyell first examined this region in 1842, Professor Hitchcock had already seen two thousand impressions of feet!

It is not difficult to imagine the conditions under which such impressions may have been preserved, for at the present day there are to be seen, on some shores, illustrations of similar operations. Dr. Gould, of Boston, U.S., was the first to call the attention of naturalists to a very instructive example of such processes on the shores of the Bay of Fundy, where the tide is said to rise in some places seventy feet high. Here we have a very perfect surface for receiving and retaining impressions. Vast are the numbers of wading and sea-birds that course to and fro over the extensive tract of plastic red surface left dry by the far retreat of the tide in the Bay of Fundy. During the period that elapses between one spring tide and the next, the highest part of the tidal deposit is exposed long enough to receive and retain many impressions; even during the hours of hot sunshine, to which, in the summer months, this so-trodden tract is left exposed, the layer last deposited becomes baked hard and dry, and before the returning tidal wave has power to break up the preceding one, the impressions left on that stratum have received a deposit. A cast is thus taken of the mould previously made, and each succeeding tide brings another layer of deposit. We can easily imagine that in succeeding ages the petrifying influences will consolidate the sandy layers into a fossil rock. Such a rock would split in such a way, along its natural layers of formation, as to show the old moulds on one surface, and the casts on the other.

Fig. 16.—Limb-bones ofAllosaurus. (After Marsh.)1. Fore leg.2. Hind leg.

Professor Marsh has had the good fortune to discover a very peculiar new form of carnivorous Dinosaur, to which he has giventhe name Ceratosaurus,[14]because its skull supported a horn. But the horn is not the only new feature presented by this interesting creature. Its vertebræ are of a strange and unexpected type; and in the pelvis all the bones are fused together, as in modern birds. Externally, also, the Ceratosaurus differed from other members of the carnivorous group, for its body was partly protected by long plates in the skin, such as crocodiles have: these extended from the back of the head, along the neck, and over the back. An almost complete skeleton was found which indicates an animal about seventeen feet long. When alive it was probably about half the bulk of the Allosaurus mentioned above. (SeeFig. 16.)

[14]Greek—keras, horn;sauros, lizard. Some authorities consider it to be identical with Megalosaurus.

Seen from above, its skull resembles in general outline that of a crocodile, the facial portion being elongated and gradually tapering to the muzzle, with the nasal openings separate, and placed near the end of the snout.

Fig. 17.—Skull ofCeratosaurus. Top view. (After Marsh.)

The teeth of this horned Dinosaur resemble those of the Megalosaur. Its eyes were protected by protuberances of the skull just above the cavity in which the eye was placed (see Figs.17and18). The brain was a good deal larger in proportion to the size of the animal than in Brontosaurus and its allies; so perhaps we may infer that it was endowed with greater intelligence, as it certainly was more active in its habits. The fore limbs, as in Megalosaurus,were small, and some of the fingers ended in powerful claws, which no doubt it used to good purpose.

Perhaps the most remarkable of all the Dinosaurs was a diminutive creature only two feet in length, which was related to those we have just been considering, and whose skeleton has been found almost entire in the now famous Lithographic Stone of Solenhofen in Bavaria. Of this unique type, the Compsognathus, the skeleton of which is in many ways so bird-like, Professor Huxley remarks, “It is impossible to look at the conformation of this strange reptile and to doubt that it hopped, or walked, in an erect or semi-erect position, after the manner of a bird, to which its long neck, slight head, and small anterior limbs must have given it an extraordinary resemblance.” (SeeFig. 19.)

Fig. 18.—Skull ofCeratosaurus nasicornis. (After Marsh.)

At the head of this chapter are placed the words of Dr. Mantell, “Fossils have been eloquently and appropriately termedMedals of Creation,” and the eloquent passage by which those words are followed may be transcribed here. He goes on to say, "For as an accomplished numismatist, even when the inscription of an ancient and unknown coin is illegible, can from the half-obliterated effigy, and from the style of art, determine with precision the people by whom, and the periodwhen, it was struck: in like manner the geologist can decipher these natural memorials, interpret the hieroglyphics with which they are inscribed, and from apparently the most insignificant relics trace the history of beings of whom no other records are extant, and ascertain the forms and habits of unknown types of organisation whose races are swept from the face of the earth, ere the creation of man, and the creatures which are his contemporaries. Well might the illustrious Bergman exclaim, "Sunt instar nummorum memoralium quæ de præteritis globi nostri fatis testantur, ubi omnia silent monumenta historica.""

Fig. 19.—Skeleton ofCompsognathus longipes. (From the Solenhofen limestone.)

Geology owes a deep debt of gratitude to the late Dr. Gideon A. Mantell, who, during the intervals of a laborious professional life, collected and described the remains of several strange extinct reptiles, and wrote a number of works on geology, such as served in his day to advance the science to which he was so enthusiastically devoted.

We propose to give a brief account of a wonderful group of Dinosaurs, first introduced to the scientific world through Dr. Mantell’s labours.

The first of these monsters is the Iguanodon, the earliest known individual of the “bird-footed” division (Ornithopoda). The history of the gradual reconstruction of its skeleton is an instructive instance of the results that may be obtained by a careful and patient study of fragmentary remains. Through the labours of Dr. Mantell, in the first half of this century, a considerable knowledge was acquired of the greater part of the skeleton, but certain portions remained a puzzle; these, however, were eventually explained by Professor Huxley and Mr. Hulke, and a few years ago a series of complete skeletons were most fortunately obtained in Belgium, so that now every part of the huge framework of this monster is known to the palæontologist. Its history, as a fossil, is a most interesting one, and furnishes one more example of the marvellous insight into the nature of extinct animals displayed by the illustrious Baron Cuvier. Let us begin with the teeth, since they were the first part of the monster brought to light.

It is, perhaps, hardly necessary to remark that, to one thoroughly acquainted with the structures of living animals, a tooth, or a series of teeth, will furnish material from which important conclusions with regard to the structure and habits of an extinct animal may be drawn. So, also, with regard to someother parts, such as limb-bones, but more especially the bones of which the backbone is composed (known as vertebræ). These are very important. The veteran anatomist, Professor Owen, has said, “If I were restricted to a single specimen on which to deduce the nature of an extinct animal, I should choose a vertebra to work out a reptile, and a tooth in the case of a mammal.” Seven or eight different “characters,” he says, may be deduced from a reptilian vertebra. It is, of course, impossible for any one to reconstruct an entire animal from a single bone or a few teeth, yet such fragments indicate in a general way the nature of a lost creation and its position in the animal kingdom.

Fig. 20.—Tooth of Iguanodon, with the apex slightly worn. (From the Wealden Beds of Tilgate Forest. Natural size.) 1. Front aspect, showing the longitudinal ridges and serrated margins of the crown. 2. View of the back, or inner surface of the tooth.a.Serrated margins.b.Apex of the crown worn by use.

It is all the more important to give to the general reader this warning, because an impression seems still to remain in the popular mind that Owen could and did restore extinct types from a single bone or a single tooth; but no anatomist would attribute to any mortal man such superhuman power. Let us, therefore,while gratefully acknowledging the debt we all owe to the great naturalist—who has gone to his rest since our first edition appeared—not attribute to him impossible things. Nor can it be denied that even he sometimes fell into error, or drew conclusions not borne out by later discoveries. It must also be confessed that in some respects he lagged behind in the march of scientific progress. While on this subject we cannot do better than quote some remarks of our friend, Mr. A. Smith Woodward, of the Natural History Museum, in an able review of Sir Richard’s work on vertebrates.[15]He says, "Owen, in fact, was Cuvier’s direct successor, and, apart from his striking hypotheses ..., it is in this character that he has left the deepest impression upon biological science. Extending and elaborating comparative anatomy as understood by Cuvier, Owen concentrated his efforts on utilising the results for the interpretation of the fossil remains—even isolated bones and teeth—of extinct animals. He never hesitated to deal with the most fragmentary evidence, having complete faith in the principles established by Cuvier; and it is particularly interesting, in the light of present knowledge, to study the long series of successes and failures that characterise his work. However, unwittingly, Owen may be said to have contributed most to the demolition of the narrow Cuvierian views. When dealing with animals closely related to those now living, his correctness of interpretation was usually assured; when treating of more remote types, he could do little more than guess, unless tolerably complete skeletons happened to be at his disposal....

“In short, Owen’s work on fragmentary fossils has demonstrated that the principles of comparative anatomy are very different from those inferred by Cuvier from his limited field of observation, and the discoveries of Leidy, Marsh, Cope, Scott, and Osborn, in America, have finally led to a new era that Owen only began to foresee clearly in his later days.”

[15]Natural Science, ii. p. 130. (Feb. 1893.)

The first specimens of teeth of the Iguanodon were found byMrs. Mantell, in 1822, in the coarse conglomerate of certain strata in Tilgate Forest, belonging to the Cretaceous period (seeTable of Strata, Appendix I.). Dr. and Mrs. Mantell subsequently collected a most interesting series of these remarkable teeth (which, for a time, puzzled the most learned men of the day), from the perfect tooth of a young animal, to the last stage, that of a mere long stump worn away by mastication. In external form they bore a striking resemblance to the grinders of herbivorous mammals, and were wholly unlike any that had previously been known. Even the quarrymen, accustomed to collect the remains of fishes, shells, and other objects embedded in the rocks, had not observed fossils of this kind; and until Dr. Mantell showed them his specimens, were not aware of the presence of such teeth in the stone they were constantly breaking up for the roads. The first specimen that arrested his attention was a large tooth, which, from the worn surface of its crown, had evidently once belonged to some herbivorous animal. In form it so entirely resembled the corresponding part of an incisor tooth of a large pachydermatous animal ground down by use, that Dr. Mantell was much embarrassed to account for its presence in the ancient Wealden strata, in which, according to all previous experience, no fossil remains of mammals would be likely to occur. No reptiles of the present day are capable of masticating their food; how, then, could he venture to assign it to a reptile? Here was a puzzle to be solved, and in his perplexity he determined to try whether the great naturalist at Paris would be able to throw any light on the question. Through Sir Charles (then Mr.) Lyell, this perplexing tooth was submitted to Baron Cuvier; and great was the doctor’s astonishment on hearing that it had been without hesitation pronounced to be the upper incisor of a rhinoceros! The same tooth, with some other specimens, had already been exhibited at a meeting of the Geological Society, and shown to Dr. Buckland, Mr. Conybeare, and others, but with no more satisfactory result. Worse than that: Dr. Mantell was told thatthe teeth were of no particular interest, and that, without doubt, they either belonged to some large fish, or were the teeth of a mammal, and derived from some superficial deposit of the “glacial drift,” then called Diluvium.

There was one man, however, who foresaw the importance of Mantell’s discovery, and that was Dr. Wollaston. This distinguished philosopher, though not a naturalist, supported the doctor’s idea that the teeth belonged to an unknown herbivorous reptile, and encouraged him to continue his researches.

As if to add to the difficulty of solving the enigma, certain bones of the fore limb, discovered soon after in the same quarry and forwarded to Paris, were declared to belong to a species of hippopotamus! Another very curious bone—of which we shall speak presently—was declared to be the lesser horn of a rhinoceros! The famous Dr. Buckland even went so far as to warn Dr. Mantell not to publish it forth that these bones and teeth had been found in the Tilgate Forest strata. To him it seemed incredible that such remains could have been obtained from beds older than the superficial drift deposits of the district. We must bear in mind that in those days palæontology, or the knowledge of the world’s former inhabitants, was a new science still in its infancy, and the idea of mammals having existed so far back as the Cretaceous period must have appeared incredible.

However, the workmen in the quarry were stimulated by suitable rewards, and at length the doctor’s efforts resulted in the discovery of teeth which displayed the curious serrated edges, and the entire form of the unused crown. Having forwarded specimens and drawings of these to Paris, Dr. Mantell went to London, and ransacked all the drawers in the Hunterian Museum that contained jaws and teeth of reptiles, but without finding any that threw light on this subject. Fortunately, Mr. Samuel Stuchbury, then a young man, was present, and proposed to show him the skeleton of an Iguana, which he had himself prepared from a specimen that had long been immersed in spirits.And now the puzzle was in a fair way to being solved; for, to his great delight, the doctor found that the minute teeth of that reptile bore a closer resemblance in their general form to those from Tilgate Forest than any others he had ever seen.

In spite of this fortunate discovery, however, others remained obstinate and unconvinced; and it was not until he had collected a series of specimens, exhibiting various stages of the teeth, that the correctness of his opinion was admitted, either as to their true interpretation, or the age of the strata in which they were imbedded. And now there came good news from Paris. Cuvier, with the fresh material submitted to him, had boldly renounced his previous opinion, and gave the weight of his great authority to the view maintained by the discoverer of these teeth. In a letter to the doctor he said that such teeth were quite unknown to him, and that they belonged to some reptile. He suggested that they implied the existence of anew animal, aherbivorous reptile. Time would either confirm or disprove the idea, and in the mean time he advised Dr. Mantell to seek diligently for further evidence, and, if part of a jaw could be found with teeth adhering, he believed he could solve the problem. In his immortal work,Ossemens Fossiles, Cuvier generously admits his former mistake, and said he was entirely convinced of his error.

Baron Cuvier alone amongst the doctor’s friends or correspondents was able to give any hint as to the character and probable relations of the animal to which the recently discovered teeth belonged. Being hampered by arduous professional duties in a provincial town, remote from museums and libraries, Dr. Mantell transmitted to the Royal Society figures and drawings of the specimens, and, at the suggestion of the Rev. W. D. Conybeare, adopted the name Iguanodon (Iguana-tooth) for the extinct reptile, a name which pointed to the resemblance of its teeth to those of the modern iguana, a land-lizard inhabiting many parts of America and the West Indies, and rarely met with north or south of the tropics. These lizards are from three to five feet inlength, and perfectly harmless, feeding on insects and vegetables, and climbing trees in quest of the tender leaves and buds, which they chip off and swallow whole; they nestle in the hollows of rocks, and deposit their eggs in the sands and banks of rivers.

In all living reptiles the insects or vegetables on which they feed are seized by the tongue or teeth, and swallowed whole, so that a movable covering to the jaws, similar to the lips and cheeks of the mammalia, is not necessary, either for seizing and retaining food, or for subjecting it by muscular movements to the action of the teeth. It is the power of perfect mastication possessed by the Iguanodon that is so strange, for it implies a most remarkable approach in extinct reptiles to characters possessed now only by herbivorous mammalia, such as horses, cows, deer, etc. From this and other strange characters seen in the Dinosaurs, we learn that they in their day played the part of our modern quadrupeds, whether carnivorous or herbivorous, and showed a remarkable approach to the mammalian type, which of course is a much higher one.

It is, therefore, not to be wondered at that Dr. Mantell’s contemporaries, with the exception of Cuvier, found in the teeth we have described an awkward puzzle, and refused to believe that they belonged to a reptile. Such a notion was at variance with all previous experience, and we naturally form our conclusions to a large extent by experience. Let us, then, beware lest we allow our ideas to be limited by what after all is, as it were, only an expression of our ignorance. The Hottentot who has never seen snow would refuse to believe that rain can assume a solid form; and, in the same way, if we bind ourselves down by experience, we might refuse to believe in some of the still more wonderful dinosaurian types to be described in this chapter, such as the Triceratops, with a pair of large horns, a skull over six feet long, and limbs larger than those of the rhinoceros! (seep. 117).

The strange vagaries of Dinosaurs have led Professor Marshand other authorities to exalt them, from their former position of a mere order in the reptile class, to the dignity of a sub-class all to themselves; and there is much to be said for this view. Compared with the Marsupials, living and extinct, they show an equal diversity of structure and variations in size from by far the largest land animals known down to some of the smallest.[16]

[16]Bauer, after a full critical examination of the Dinosauria, considers that one order is insufficient, and has proposed to make three orders of them, which he names after the Iguanodon, Cetiosaurus, and Megalosaurus.

The importance of discovering, if possible, a portion of the jaw of an Iguanodon was fully recognised by Dr. Mantell, and, urged on by the encouragement he had received from the illustrious Cuvier, he eagerly sought for the required evidence. But nearly a quarter of a century elapsed before it was forthcoming. In 1841 and 1848, however, portions of the lower jaw, with some teeth attached, were found; and his memoirOn the Structure of the Jaws and Teeth of the Iguanodonwas published by the Royal Society in 1848. For this important communication the gold medal of the society was awarded to the author. The second of these finds (by Captain Brickenden) confirmed in every essential particular the inferences suggested by the detached teeth.

The first important connected series of bones of this monster was discovered in 1834, by Mr. Bensted, in the “Kentish Rag” quarries of the Lower Greensand formation at Maidstone. Mr. Bensted, who was the proprietor of the quarry, one day had his attention drawn by the workmen to what they supposed to be petrified wood in some pieces of stone which they had been blasting. He perceived that what they supposed to be wood was fossil bone, and, with a zeal and care which have always characterised this estimable man (says Professor Owen) in his endeavour to secure for science any evidence of fossil remains in his quarry, he immediately resorted to the spot. He found that the bore, or blast, by which these remains were brought to lighthad been inserted into the centre of the specimen, so that the mass of stone containing it had been shattered into many pieces, some of which were blown into the adjoining fields! All these pieces he had carefully collected, and, proceeding with equal ardour and success to the removal of the matrix from the fossils, he succeeded, after a month’s labour, in exposing them to view, and in fitting the fragments in their proper place. This valuable specimen was presented to Dr. Mantell (and afterwards purchased with the rest of his collection by the British Museum), and its present condition is the result of his skill, as well as that of its discoverer. Certain gentlemen in Brighton, anxious that the specimen should be placed in the hands of the original discoverer of Iguanodon, purchased and presented it to Dr. Mantell—a tribute of respect which was highly gratifying to him. (Wall-case 6.)

It belonged to a young Iguanodon. This fortunate discovery was one of those Cuvier foresaw, and has served to verify his sagacious conjecture that some of the great bones collected by the doctor from the Wealden strata of Sussex belonged to the same animal, and to confirm other conclusions formed by the discoverer of the Iguanodon. Great was Dr. Mantell’s delight on finding that every bone he had ascribed to Iguanodon solely from analogy was present in the Maidstone specimen. One of the chief advantages of this discovery was that it afforded demonstration of the characters of the vertebræ, which, as previously stated, are very important to the anatomist. Of these Professor Owen has given full descriptions, and has shown that they differ from those of any animal previously known, whether living or extinct.

It is very interesting, in the light of recent discoveries, to read the conclusions arrived at by Mantell and Owen, with regard to the organisation of this great Wealden reptile, and to see how, with the exception of certain details, they have been confirmed. Considering the imperfect nature of the materials attheir command, it is wonderful that their forecasts should have turned out so successful. Thus Professor Owen predicted for the Iguanodon a total length of twenty-eight feet, and specimens discovered of late years show a length of twenty-four feet. In some, the thigh-bone exceeded a yard in length; this indicated an animal of great size, since in the largest crocodiles this bone is scarcely a foot long. Again, Dr. Mantell, from a study of the imperfect jaw-bones in his collection, concluded that the lower jaw was invested with a well-developed fleshy flexible lip, and that the mouth was provided with a tongue of great mobility and power. “There are strong reasons,” he says, "for supposing that the lip was flexible, and, in conjunction with the long fleshy prehensile tongue, constituted the instrument for seizing and cropping the leaves and branches, which, from the construction of the molars, we may infer, constituted the chief food of the Iguanodon. The mechanism of the maxillary organs (jaws), as elucidated by recent discoveries, is thus in perfect harmony with the remarkable characters which rendered the first known teeth so enigmatical; and in the Wealden herbivorous reptile we have a solution of the problem, how the integrity of the type of organisation peculiar to the class of cold-blooded vertebrata was maintained, and yet adapted, by simple modifications, to fulfil the conditions required by the economy of a gigantic terrestrial reptile, destined to obtain support exclusively from vegetable substances; in like manner, as the extinct colossal herbivorous Edentata (sloths, SeeChapter XII.), which flourished in South America ages after the country of the Iguanodon and its inhabitants had been swept away from the face of the earth."

Dr. Mantell also was the first to prove, from the nature of the Wealden strata, that they were deposited in or near the estuary of a mighty river. With regard to the aspect of the country in which the Iguanodon flourished, he showed that coniferous trees probably clothed its Alpine regions; palms and arborescent ferns, and cycadaceous plants (i.e.plants resembling the modern zamia, or “false palm”), constituted the groves and forests of its plains and valleys; and in its fens and marshes the equisetaceæ (mare’s-tails) and plants of a like nature prevailed.

Plate VII.

A GIGANTIC DINOSAUR, IGUANODON BERNISSARTENSIS.Length about 30 feet.

The Iguanodons of the Wealden epoch did not live and die where their bones are now found—the condition in which their fossil relics occur proves that they floated down the streams and rivers, with rafts of trees and other spoils of the land, till, arrested in their course, they sank down and became buried in the fluviatile and sometimes marine sediments then being slowly laid down. In this way only can we account for the generally broken and rolled condition of the bones, their separation from each other, the numerous specimens of teeth which must have been detached from their sockets, and the broken stems and branches of trees without leaves that have been found in the Wealden strata of England.

Since the days of Dr. Mantell, the remains of Iguanodon, or closely allied genera, have been found on the continent, in other parts of England, and in North America, in strata of various ages, from the Trias or New Red Sandstone to the Chalk (seeTable of Strata, Appendix I.). The American Hadrosaurus must have decidedly resembled the Iguanodon.

The beautiful restoration by our artist (plate VII.) is based upon the Belgian specimens described in the following chapter.

CHAPTER VII.

DINOSAURS (continued).

“Everything in Nature is engaged in writing its own history: the planet and the pebble are attended by their shadows, the rolling rock leaves its furrows on the mountain side, the river its channel in the soil, the animal its bones in the stratum, the fern and the leaf inscribe their modest epitaphs on the coal, the falling drop sculptures its story on the sand and on the stone,—not a footstep on the snow or on the ground, but traces in characters more or less enduring the record of its progress.”—Emerson.

In the year 1878 was announced one of the most fortunate discoveries known in the whole history of geological science—a discovery unique of its kind, and one which throws considerable light on the nature of the monster first discovered by Dr. Mantell. In that year came the good news that no less than twenty-three Iguanodons had been found in the colliery of Bernissart, in Belgium, between Mons and Tournai, near the French frontier. The coal-bearing rocks (coal-measures) of this colliery, overlain by chalk and other deposits of later age, are fissured in many places by deep valleys or chasms more than 218 yards deep. Though now filled up, they must at one time have been open gorges on an old land surface. Into one of these chasms were somehow precipitated twenty-three Iguanodons, numbers of fish, a frog-like animal, several species of turtles, crocodiles, and numerous ferns similar to those described by Mantell from the Weald. It it not easy to conjecture how this large and varied assemblage of animals came to be collected together and entombed in this one place, but possibly their carcases wereswept by some flood into the chasm in which the remains were discovered. They were buried in clay interstratified with sand, a fact which was interpreted in accordance with the above suggestion.

M. de Pauw, the accomplished controller of the workshops in the Royal Museum of Natural History at Brussels, spent three whole years in extracting this splendid series of fossils from the pit-shaft, the bones being brought up from a depth of rather more than 350 yards. But at the end of this time it was only the rough material that had been got together, and every block containing bones requires a great deal of most careful labour before the bones in it are so exposed that they can be properly studied. Out of the twenty-three specimens, fifteen had, in the year 1883, been chiselled out, eight remaining to be worked at; and although five skilled workmen were then constantly at work, progress was necessarily slow.

In 1883, that is after seven years, two huge entire skeletons had been set up in a great glass case in the Courtyard of the Museum at Brussels, and these exhibit with marvellous completeness the structure of the extinct monster.[17]The work reflects the highest credit on M. de Pauw;[18]and the director of the Bernissart Mining Company, M. Fages, deserves the thanks of all scientific men for so liberally aiding this important undertaking. These specimens illustrate the conclusion, previously arrived at by Professor Huxley, that Dinosaurs, as a group, occupy a position in the great chain of animal life intermediate between reptiles and birds. Indeed, it is the opinion of this great authority, and of many naturalists of the present day, that whenever future discoveries may reveal the ancestry of birds, it will be found that they came from Dinosaurs, or that both originated from a common ancestor.

[17]In August, 1892, Mr. Dollo wrote, in answer to inquiries from South Kensington, to say that five are already mounted and exhibited, and five more are almost ready for mounting. He also stated that the remains represent twenty-nine individuals, not twenty-three, as above.

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