CHAPTER VII

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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 were swept 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.

[18] _Geological Magazine_, January, 1885.

The specimens so skilfully set up by M. de Pauw represent two distinct species. The larger one, Iguanodon Bernissartensis, cannot be less than fifteen feet high, and, measured from the tip of the snout to the end of the tail, is rather over thirty feet long, covering nearly twenty-four feet of ground in its erect position (see Fig. 21). Iguanodon Mantelli is smaller and more slender looking, with a height of over ten feet, and a length of about twenty feet. (See Fig. 22.)

[Illustration: Fig. 21.--Skeleton of _Iguanodon Bernissartensis_.]

[Illustration: Plate VIII.

IGUANODON MANTELLI.

Length about 20 feet.]

[Illustration: Fig. 22.--Skull and skeleton of _Iguanodon Mantelli_. (From Bernissart.)]

The huge three-toed impressions found in Sussex prove that the monster, although owning a body as large as that of an elephant, habitually walked on its hind legs! Some of the thighbones found by Dr. Mantell measured between four and five feet in length. It will be seen that the fore limbs are small in comparison to the hind limbs. A remarkable feature of the hand is the large pointed bone at the end of the thumb, forming a kind of spur. The conical shape of this bone found by Dr. Mantell, who had no clue to its place in the skeleton, led him to suppose that it was a horn answering to that of a rhinoceros--a conclusion which Professor Owen refused for various reasons to accept. The latter concluded that it belonged to the hand, and now we see that he was right. Unfortunately, certain popular works on geology, such as _Our Earth and its Story_ (Cassell) still continue to spread this error, by showing a (very indifferent) restoration of the Iguanodon with the impossible horn on its nose. It has been suggested that the spur was a weapon of offence, and that, when attacked, an Iguanodon may have seized its aggressor in its short arms, and made use of the spur as a dagger. But this is only conjecture, and perhaps the spur may have been useful in seizing and pulling down the foliage and branches of trees, or in grubbing them up by the roots. Detached specimens of this curious bone may be seen among the other remains of Iguanodon at South Kensington, and also some of the gigantic tracks already alluded to. (Gallery IV. on plan, Wall-cases 5 and 6; and Gallery XI., Wall-case 7.)

The Bernissart specimens even afford some evidence as to the nature of the integument, or skin, and this supports the idea previously held that the creature possessed a smooth skin, or, at least, only slightly roughened. The muzzle was quite toothless, and perhaps may have been sheathed in horn, like the beak of turtles--an arrangement highly useful for biting off the leaves of trees.

[Illustration: Fig. 23.--Tracks of _Iguanodon_, much reduced. (From Wealden strata, Sussex.)]

Probably it passed much of its time in the water, using its immense powerful tail as an organ of propulsion. When swimming slowly it may have used both sets of limbs, but when going fast it probably fixed its fore limbs closely beside its body, and drove itself through the water by means of the long hind limbs alone. Mr. Dollo, of Brussels, is preparing a final monograph on the Bernissart Iguanodons, a work to which palæontologists eagerly look forward. There cannot be much doubt that these unarmoured Dinosaurs were molested and preyed upon by their carnivorous contemporaries, such as the fierce Megalosaurus, previously described (p. 76). And with regard to this, Mr. Dollo makes the suggestion that, when on land, their great height and erect posture enabled them to descry such enemies a long way off. Their great height must also have stood them in good stead, by enabling them easily to reach the leaves of trees, tree-ferns, cycads, and other forms of vegetable life, which constituted their daily food. (See restorations, Plates VII. and VIII.)

Should the reader visit the "geological island" in the grounds of the Crystal Palace, he will see that Mr. Waterhouse Hawkins's great model Iguanodon there set up is by no means in accordance with the description given above; but we must remember how imperfect was the material at his command.

Another Dinosaur, of considerable dimensions, that flourished during the Wealden period was the Hylæosaurus, also discovered by Dr. Mantell, and so named by him because it came from the Weald.[19] In the summer of 1832, upon visiting a quarry in Tilgate Forest, which had yielded many organic remains, he perceived in some fragments of a large mass of stone which had recently been broken up and thrown in the roadside, traces of numerous pieces of bone. With great care he cemented together and fixed in a stout frame, all the portions of this block that he could find, and set to work to "develop" the block with his chisel. This work occupied many weeks, but his labour was rewarded by the discovery of certain new and remarkable features displayed by this monster; for it must have presented, when alive, a formidable array of bony plates and long sharp spines, the latter of which probably stood in bristling array along the back and tail, and other parts of the body. (Wall-case 4.) Of the spines no less than ten were found in this block, varying in length from five to seventeen inches, the largest being four inches thick. It is known that many lizards, such as Iguanas and Cycluras, have large processes with horny coverings, forming a kind of fringe or crest along the back, and, judging by analogy, Dr. Mantell concluded that this gigantic saurian was similarly armed with a row of large angular spines covered by a thick horny investment. As weapons of offence and defence, they were no doubt highly effective, but their precise arrangement is still a matter of speculation.

[19] From Greek--_hule_, wood, or weald; and _sauros_, lizard.

This first specimen displayed, besides the bony scutes and spines, a portion of the backbone, eleven ribs and portions of the pectoral arch. A second specimen was found near Bolney, in Sussex, and was unfortunately almost wholly destroyed by the labourers; but Dr. Mantell was able to obtain many of the bones, such as ribs and limb-bones, and they also indicated a reptile of great size. A third specimen was brought to light in Tilgate Forest in 1837; but, unfortunately, this also fell into the hands of the parish labourers, who were unacquainted with its value. Although with due care a much larger portion of the skeleton might have been kept, yet Dr. Mantell was able to obtain a fine series of twenty-six vertebræ belonging to the tail, with a total length of nearly six feet: the same spines were present here also.

No specimen of the skull of this strange monster is known, and no teeth that can be with certainty referred to it.

Mr. Waterhouse Hawkins's model at Sydenham, near the Iguanodon, was based on the above discoveries, which are insufficient, and is far from the truth.

[Illustration: Plate IX.

AN ARMOURED DINOSAUR, SCELIDOSAURUS HARRISONI.

Length 12 feet or more.]

[Illustration: Fig. 24.--Restored skeleton of _Scelidosaurus Harrisoni_ (after Woodward), greatly reduced, from the Lower Lias of Charmouth, Dorset. The figure shows the large lateral dermal spines on the shoulders, and the long lateral line of smaller spines, reaching from the pectoral region to the extremity of the tail.]

* * * * *

The next monster to be described is one that has fortunately left to posterity a much better record of itself, and probably was not very unlike the Hylæosaurus of Mantell. This is the Scelidosaurus: so named by Professor Owen from the indications of greater power in the hind legs than in most saurians.[20] It is the only known example of an almost entire skeleton of an English Dinosaur, and the history of its discovery is rather curious. Some time previous to 1861, Mr. J. Harrison, of Charmouth, obtained from the Lower Lias of that neighbourhood portions of the hind limb of a Dinosaur, and, later on, a nearly complete skull. These specimens were described by Owen, and the genus was founded on them. Mr. Harrison, whose discovery aroused great interest, continued to search on the same spot, and was rewarded by finding all the rest of the skeleton, except most of the neck vertebræ. This was extracted in several blocks, and these, after careful "development" of the bones, were fitted together so as to exhibit the whole skeleton. This most valuable specimen can now be seen at South Kensington in a separate glass case, and is one of the treasures of the unrivalled gallery of fossil reptiles. The case is placed so that both sides of the specimen can be seen (Case Y, Gallery IV., on plan). Its length is about twelve feet; perhaps the individual it represents was not fully grown, but, on account of the absence of most of the neck vertebræ, it is impossible to give the exact length. Both hind limbs are entire and well seen, but of the fore limbs the hands are wanting. The former were provided with four "functional" toes--that is, toes that were used,--and one "rudimentary" or unused one. There were two big spines, one placed on each shoulder, and a series of long plates arranged in lines along the back and side. Plate IX. shows an attempted restoration of this remarkable Dinosaur based upon the skeleton just described. It seems to have been organised for a terrestrial rather than an aquatic life, but to have been amphibious, frequenting the margins of rivers or lakes. Professor Owen considers that the carcase of this individual drifted down a river emptying itself in the old Liassic Sea, on the muddy bottom of which it would settle down when the skin had been so far decomposed as to permit the escape of gases due to decomposition. In that case the carcase would attract large carnivorous fishes and reptiles, such as swarmed in this old sea, so that portions of the skin and flesh would probably be torn away before the weight of the bones had completely buried it in mud. In this way, perhaps, the loss of much of the external armature and of the two fore feet may be accounted for. The hind limbs, being stronger, were better able to resist such attacks, and they are therefore preserved. Like many other specimens, this fossil has, in the course of ages, been subjected to enormous pressure from overlying strata, causing compression and dislocation or fracture.

[20] From Greek--_scelis_, limb, and _sauros_, lizard.

But there were in existence during the long Jurassic period, other and even stranger forms of armoured Dinosaurs. One of these, only imperfectly known at present, was the many-spined Polacanthus.[21] This remarkable monster had the whole region of the loins and haunches protected by a continuous sheet of bony plate armour, rising into knobs and spines, after the fashion of the shield or carapace of certain extinct armadillos known as Glyptodonts (see