A Pictorial Atlas of Fossil Remains, consisting of coloured illustrations selected from Parkinson's "Organic remains of a former world," and Artis's "Antediluvian phytology."

by Gideon Algernon Mantell

In the course of last summer I obtained a very instructive fragment of the middle part of the right ramus of the lower jaw of a much larger Iguanodon, found by Mr. Fowlestone, with some enormous bones of the extremities, in the Wealden strata of the Isle of Wight. A portion of the upper jaw (without teeth) was discovered some years since in Tilgate Forest, and is deposited, with the whole of the collection I formed at Brighton, in the gallery of organic remains of the British Museum. These three specimens are the only parts of the jaws of the Iguanodon, with the exception of a fragment of the angular bone, that I have had the opportunity of examining. The other portions of the skeleton hitherto discovered are the following: the tympanic bone;[134] cervical, dorsal, lumbar, and caudal vertebræ, and chevron bones; ribs; the iliac bones, and sacrum composed of six anchylosed vertebræ;[135] the coracoid, scapula and clavicles; humerus, radius? metacarpals; femur, tibia and fibula, metatarsals and ungueals. The cranium, carpals, and tarsals, have not been discovered.

[134] This may or may not belong to the Iguanodon: no tympanic bone has been found in such connexion with other parts of the skeleton as to afford certain proof that this maxillary element is referable to the Iguanodon.

[135] In the Megalosaurus, the sacrum consists of five anchylosed vertebræ.

With the exception of the assemblage of bones promiscuously grouped together in a block of Kentish rag (of the greensand formation), found in a quarry near Maidstone, by Mr. Bensted, [136] a few connected caudal vertebræ, and two or three instances in which a femur, tibia, and fibula and some metatarsals, were found in contiguity, all the bones were isolated. They have been obtained from the quarries in St. Leonard's and Tilgate Forests, near Loxwood, Rusper, Horsham, Cuckfield, and Battel; and from the cliffs at Hastings, and in Sandown, and Brixton, and Brook Bays, on the southern shore of the Isle of Wight.

[136] This most instructive specimen is in a glass-case on the floor near the window, in the middle room of the Gallery of Organic Remains in the British Museum. All the Wealden reptilian remains of a large size, collected by me when residing in Sussex, are in the upright glass cases in the same apartment.

So anomalous is the osteology of the Iguanodon compared with that of existing saurians, that from my discovery of the first vestige of this reptile—a fragment of a tooth—thirty years ago, to the recent important acquisition of the jaws, I have had to contend with the opposition of eminent naturalists, who have refused assent to the physiological inferences suggested by the specimens which were from time to time brought to light, because the modifications of structure in a colossal herbivorous reptile, essentially differed from the hypothetical archetype skeleton of the class to which it belonged. When the first discovered teeth were shown to Baron Cuvier, he pronounced them to be the incisors of a Rhinoceros; the metatarsals, those of a Hippopotamus; the fragment of a femur, with a medullary canal, that of some large mammalian. But the candour and liberality of the founder of Palæontology were worthy of his transcendent genius; upon receiving further evidence, he immediately acknowledged the error, and expressed his conviction that the teeth and bones belonged to an herbivorous reptile more extraordinary than any that had previously been brought under his notice.[137]

[137] See Cuvier's Ossemens Fossiles, tom. v. part. ii. It is much to be wished that those who aspire to emulate this great man in scientific fame, would also endeavour to imitate him in the yet nobler attributes of his character. It is stated by Professor Owen, in Brit. Assoc. Reports on Fossil Reptiles, that the bones of the Iguanodon were interpreted by me with the aid of Cuvier and Clift. This is a mistake. Baron Cuvier died before I had obtained any considerable portion of the skeleton; and neither Mr. Clift nor Mr. Owen at that time could afford me any assistance in determining the nature of the isolated bones I occasionally brought to the Hunterian Museum for comparison. Any aid I ever received in my investigations is most fully acknowledged in my works.

Even the lower jaw, which presents characters so peculiar as to admit, as I conceive, of but one interpretation—that enunciated in my memoir on the teeth and jaws of the Iguanodon,[138]—has been adduced as affording a signal instance of the incorrectness of my physiological deductions. And why? Because in the entire class of living reptiles there is not a single species that has cheeks and flexible lips, which, according to my view of the subject, the Iguanodon must have possessed. But I do not hesitate to affirm that the structure and arrangement of the teeth, and the mammalian character of the bones of the extremities, are in perfect accordance with my exposition of the probable structure and functions of the maxillary organs of the original. The naturalists who advance these objections, forget that among the existing mammalia there is one genus, the Ornithorhynchus, or Duck-billed Platypus, that exhibits as striking a deviation from the typical maxillary structure of its class, as does the Iguanodon. If before the discovery of New Holland the jaw-bones of the Ornithorhynchus had been found in a fossil state in the strata of Tilgate Forest, and I had ventured to infer that the original, though a true mammalian, and giving suck to its young, had the extremities of the jaws covered with flat horny beaks, like those of a duck, instead of with the fleshy lips and integuments which are the peculiar attributes of its class, what censures would not my temerity have called forth! We cannot too often be reminded of the profound remark of William Penn: "Experience, which is continually contradicting theory, is the only test of truth."

[138] See Philosophical Transactions, Part II. 1848.

The following are the physiological inferences relating to the structure and habits of the Iguanodon, which Dr. Melville and myself conceive our investigations have established: the discovery of the cranium, and of perfect examples of the upper and lower jaws with both successional and mature molars in their natural position, may modify, but, we believe, will in no material respect invalidate these conclusions.