Part 26

There is still another in the oolite of England; but there have only been found some portions of its cranium, which do not suffice to afford a complete idea of it.

Another very remarkable genus of reptiles, the remains of which, although they are also found beyond the limits of the lias concretion, are especially abundant in the oolite and upper sands, is the megalosaurus, justly so named, for, along with the forms of the lizards, and particularly of the monitors, of which it has also the sharp-edged and dentated teeth, it presents so enormous a size, that if we suppose it to have possessed the proportions of the monitors, it must have exceeded seventy feet in length. It was, in fact, a lizard of the size of a whale. It was discovered by Mr Buckland in England; but we have it also in France; and in Germany there are found bones, if not of the same species, at least of a species which can be referred to no other genus. It is to M. Sœmmering that we owe the first description of this last. He discovered the bones in strata lying above the oolite, in those limestone-schists of Franconia, long celebrated for the numerous fossil remains which they furnished to the cabinets of the curious, and which will be still more celebrated for the services which their employment in lithography render to the arts and sciences.

The crocodiles continue to make their appearance in these schists, and always of the long-muzzled or rostrated kind. M. de Sœmmering has described one (the Crocodilus priscus), the entire skeleton of a small individual of which was found nearly in as good a state of preservation, as it could have been in our cabinets. It is one of those which most resemble the present gavial of the Ganges; the anterior or united part of its lower jaw, however, is less elongated; its lower teeth are alternately and regularly longer and shorter. It has ten vertebræ in the tail.

But the most remarkable animals which these limestone slates contain, are the flying lizards, which I have named Pterodactyli.

They are reptiles whose principal characters are, a very short tail, a very long neck, the muzzle much elongated, and armed with sharp teeth; the legs also long, and one of the toes of the anterior extremity excessively elongated, having probably served for the attachment of a membrane adapted for supporting them in the air, accompanied with four other toes of ordinary size, terminated by hooked claws. One of these strange animals, whose appearance would be frightful did they occur alive at the present day, may have been of the size of a thrush, the other of that of a common bat; but it would appear from some fragments that larger species had existed.

A little above the limestone slates is found the nearly homogeneous limestone of the Jura ridges. It also contains bones, but always of reptiles, crocodiles, and fresh-water tortoises, of which a vast quantity is found in particular in the neighbourhood of Soleure. They have been very carefully searched for by M. Hugi; and, from the fragments which he has already collected, it is easy to recognise a considerable number of Fresh-water Tortoises, or Emydes, which further discoveries can alone determine, but of which several are already distinguished by their size and peculiar forms, from all the species hitherto known.

It is among these innumerable oviparous quadrupeds, of all sizes and forms; in the midst of these crocodiles, tortoises, flying reptiles, huge megalosauri, and monstrous plesiosauri, that some small Mammifera are said to make their appearance for the first time; and the assertion is so far authenticated by the occurrence of jaws, and some other bones discovered in England, which undoubtedly belong to this class of animals, and particularly to the family of Didelphides, or to that of the Insectivora.

It may, however, be supposed, that the stoney matters which encrust these bones, owe their origin to some local recomposition, posterior to the original formation of the strata. However this may be, it is still found for a long time that the class of Reptiles predominates.

The ferruginous sands, placed in England above the chalk, contain abundance of crocodiles, tortoises, megalosauri, and especially a reptile which presents a character quite peculiar, in as much as its teeth appear worn, like those of our herbivorous mammifera.

To Mr Mantell of Lewes, in Sussex, we are indebted for the discovery of this latter animal, as well as of other large reptiles belonging to the sands lying beneath the chalk. He has named it Iguanodon.

In the chalk itself there are only reptiles to be seen: there are found in it remains of tortoises and crocodiles. The famous tufaceous quarries of the mountain of St Peter, near Maestricht, which belong to the chalk formation, along with very large sea tortoises, and a multitude of marine shells and zoophytes, have afforded a genus of lizards not less gigantic than the megalosaurus, which has become celebrated by the researches of Camper, and the figures which Faujas has given of its bones, in his history of that mountain.

It was upwards of five and twenty feet long; its large jaws were armed with very strong conical teeth, a little arcuate, and marked with a ridge, and it had also some of these teeth in the palate. Upwards of a hundred and thirty vertebræ were counted in its spine; they were convex before, and concave behind. Its tail was deep and flat, and formed a large vertical oar (or organ of swimming). Mr Conybeare has recently proposed to name it Mosasaurus.

The clays and lignites which cover the upper part of the chalk, I have only found to contain crocodiles; and I have every reason to think that the lignites which in Switzerland have afforded beaver and mastodon bones, belong to a later epoch. Nor has it been at an earlier period than that of the coarse limestone which rests upon these clays that I have begun to find bones of mammifera; and still do they all belong to marine mammifera, to dolphins of unknown species, lamantins and morses.

Among the dolphins, there is one, the muzzle of which, more elongated than that of any known species, has the lower jaw united in a considerable part of its length, nearly as in a gavial. It was found near Dax by the late president of Borda.

Another species, from the cliffs of the Department de l’Orne, has the muzzle also long, but somewhat differently shaped.

The entire genus of lamantins is at the present day confined to the seas of the torrid zone; and that of the morses, of which only a single living species is known to exist, is limited to the frozen ocean. Yet we find skeletons of these two genera side by side in the coarse limestone strata of the middle of France; and this association of species, the nearest allied to which are, at the present day, found in opposite zones, will again make its appearance more than once as we proceed.

Our fossil lamantins differ from those known to exist at present, in having the head more elongated, and of a different form. Their ribs, which are easily recognised by their being of a thick and rounded form, and of dense texture, are not of rare occurrence in our different provinces.

With regard to the fossil morse, small fragments only have as yet been found of it, which are insufficient for characterising the species.

It is only in the strata that have succeeded the coarse limestone, or, at most, those which may have been of contemporaneous formation with it, but deposited in fresh-water lakes, that the class of land mammifera begins to shew itself in any quantity.

I consider as belonging to the same period, and as having lived together, but perhaps in different spots, the animals whose bones are deposited in the molasse and old gravel beds of the south of France; in the gypsums mixed with limestone, such as those of Paris and Aix; and in the fresh-water marly deposits covered with marine beds, of Alsace, the country of Orleans and of Berry.

This animal population possesses a very remarkable character in the abundance and variety of certain genera of pachydermata, which are entirely awanting among the quadrupeds of our days, and whose characters have more or less resemblance to those of the tapirs, the rhinoceroses, and camels.

These genera, the entire discovery of which is my own, are the palæotheria, lophiodonta, anaplotheria, anthracotheria, cheropotami, and adapis.

The Palæotheria have resembled the tapirs in their general form, and in that of the head, particularly in the shortness of the bones of the nose, which announces that they have had a small proboscis like the tapirs, and, lastly, in their having six incisors and two canine teeth in each jaw; but they have resembled the rhinoceros in their grinders, of which those of the upper jaw have been square, with prominent ridges of various configuration, and those of the lower jaw in the form of double crescents, as well as in their feet, all of which have been divided into three toes, while in the tapirs the fore feet have four.

It is one of the most extensively diffused genera and most numerous in species that occur in the deposits of this period.

Our gypsum quarries in the neighbourhood of Paris are full of them. Bones of seven distinct species are found there. The first (P. magnum) is as large as a horse. The three next are of the size of a hog, but one of them (P. medium) has narrow and long feet, another (P. crassum) has the feet broader, and a third (P. latum) has them still broader, and especially shorter. The fifth species (P. curtum), which is of the size of a sheep, is much lower, and has the feet still broader and shorter in proportion than the last. The sixth (P. minus) is of the size of a small sheep, and has long and slender feet, the lateral toes of which are shorter than the rest. The seventh (P. minimum), which is not larger than a hare, has also the feet slender.

Palæotheria have also been found in other districts of France: at Puy in Valey, in strata of gypseous marl, a species (P. velaunum), much resembling (P. medium), but differing from it in the form of its lower jaw; in the neighbourhood of Orleans, in strata of marly rock, a species (P. aurelianense), which is distinguished from the others by having the re-entering angle of the crescent of its lower grinders split into a double point, and by some differences in the necks of the upper grinders; near Issel, in a bed of gravel or molasse, along the declivities of the Black Mountain, a species (P. isselanum), which has the same characters as the Orleans species, but is of smaller size. It is more particularly, however, in the molasse of the Department of the Dordogne, that the palæotherium occurs not less abundantly than in our gypsum deposits in the neighbourhood of Paris.

The Duke Decaze has discovered in the quarries of a single field, bones of three species which appear different from all those of our neighbourhood.

The Lophiodons approach still somewhat nearer to the tapirs than the palæotheria do, inasmuch as their lower false grinders have transverse necks like those of the tapirs.