Part 34

1. Cycollites elliptica; Thecosmilia rudis; Enallocœnia ramosa; Meandrina Pyrenaica; Synhelia Sharpeana. 2. Orbitoides media; Lituola nautiloidea; Flabellina rugosa. 3. Coscinopora cupuliformis; Camerospongia fungiformis.

Among the numerous beings which inhabited the Upper Cretaceous seas there is one which, by its organisation, its proportions, and the despotic empire which it would exercise in the bosom of the waters, is certainly most worthy of our attention. We speak of the Mosasaurus, which was long known as the great animal of Maestricht, because its remains were found near that city in the most modern of the Cretaceous deposits.

In 1780 a discovery was made in the quarries of Saint Peter’s Rocks, near Maestricht, of the head of a great Saurian, which may now be seen in the Museum of Natural History in Paris. This discovery baffled all the science of the naturalists, at a period when the knowledge of these ancient beings was still in its infancy. One saw in it the head of a Crocodile; another, that of a Whale; memoirs and monographs rained down, without throwing much light on the subject. It required all the efforts of Adrian Camper, joined to those of the immortal Cuvier, to assign its true zoological place to the Maestricht animal. The controversy over this fine fossil engaged the attention of the learned for the remainder of the last century and far into the present.

Maestricht is a city of the Netherlands, built on the banks of the Meuse. At the gates of this city, in the hills which skirt the left or western bank of the river, there rises a solid mass of cretaceous formation known as Saint Peter’s Rocks. In composition these beds correspond with the Meudon chalk beds, and they contain similar fossils. The quarries are about 100 feet deep, consisting in the upper part of twenty feet abounding in corals and Polyzoa, succeeded by fifty feet of soft yellowish limestone, furnishing a fine building stone, which has been quarried from time immemorial, and extends up to the environs of Liège; this is succeeded by a few inches of greenish soil with Encrinites, and then by a very white chalk with layers of flints. The quarry is filled with marine fossils, often of great size.

These fossil remains, naturally enough, attracted the attention of the curious, and led many to visit the quarries; but of all the discoveries which attracted attention the greatest interest attached to the gigantic animal under consideration. Among those interested by the discovery of these strange vestiges was an officer of the garrison of Maestricht, named Drouin. He purchased the bones of the workmen as the pick disengaged them from the rock, and concluded by forming a collection in Maestricht, which was spoken of with admiration. In 1766, the trustees of the British Museum, hearing of this curiosity, purchased it, and had it removed to London. Incited by the example of Drouin, Hoffmann, the surgeon of the garrison, set about forming a similar collection, and his collection soon exceeded that of Drouin’s Museum in riches. It was in 1780 that he purchased of the quarrymen the magnificent fossil head, exceeding six feet in length, which has since so exercised the sagacity of naturalists.

Hoffman did not long enjoy the fruits of his precious prize, however; the chapter of the church of Maestricht claimed, with more or less foundation, certain rights of property; and in spite of all protest, the head of the Crocodile of Maestricht, as it was already called, passed into the hands of the Dean of the Chapter, named Goddin, who enjoyed the possession of his antediluvian trophy until an unforeseen incident changed the aspect of things. This incident was nothing less than the bombardment and surrender of Maestricht to the Army of the North under Kleber, in 1794.

The Army of the North did not enter upon a campaign to obtain the crania of Crocodiles, but it had on its staff a savant who was devoted to such pacific conquests. Faujas de Saint-Fond, who was the predecessor of Cordier in the Zoological Chair of the Jardin des Plantes, was attached to the Army of the North as Scientific Commissioner; and it is suspected that, in soliciting this mission, our naturalist had in his eye the already famous head of the Crocodile of the Meuse. However that may be, Maestricht fell into the hands of the French, and Faujas eagerly claimed the famous fossil for the French nation, which was packed with the care due to a relic numbering so many thousands of ages, and dispatched to the Museum of Natural History in Paris. On its arrival, Faujas undertook a labour which, as he thought, was to cover him with glory. He commenced the publication of a work entitled “The Mountain of Saint Peter of Maestricht,” describing all the fossil objects found in the Dutch quarry there, especially the Great Animal of Maestricht. He endeavoured to prove that this animal was a Crocodile.

Unfortunately for the glory of Faujas, a Dutch savant had devoted himself to the same study. Adrian Camper was the son of a great anatomist of Leyden, Pierre Camper, who had purchased of the heirs of the surgeon Hoffman some parts of the skeleton of the animal found in the quarry of Saint Peter. He had even published in the Philosophical Transactions of London, as early as 1786, a memoir, in which the animal is classed as a Whale. At the death of his father, Adrian Camper re-examined the skeleton, and in a work which Cuvier quotes with admiration, he fixed the ideas which were until then floating about. He proved that the bones belonged neither to a Fish, nor a Whale, nor to a Crocodile, but rather to a particular genus of Saurian Reptiles, or marine lizards, closely resembling in many important structural characters, existing Monitors and Iguanas, and peculiar to rocks of the Cretaceous period, both in Europe and America. Long before Faujas had finished the publication of his work on La Montagne de Saint-Pierre that of Adrian Camper had appeared, and totally changed the ideas of the world on this subject. It did not, however, hinder Faujas from continuing to call his animal the Crocodile of Maestricht. He even announced, some time after, that Adrian Camper was also of his opinion. “Nevertheless,” says Cuvier, “it is as far from the Crocodile as it is from the Iguana; and these two animals differ as much from each other in their teeth, bones, and viscera, as the ape differs from the cat, or the elephant from the horse.”

a, skull of Monitor Niloticus; b, under-jaw of same.]

The masterly memoir of Cuvier, while confirming all the views of Camper, has restored the individuality of this surprising being, which has since received the name of Mosasaurus, that is to say, Saurian or Lizard of the Meuse. It appears, from the researches of Camper and Cuvier, that this reptile of the ancient world formed an intermediate genus between the group of the Lacertilia, which comprehends the Monitors (represented in Fig. 145), and the ordinary Lizards; and the Lacertilia, whose palates are armed with teeth, a group which embraces the Iguana and the Anolis. In respect to the Crocodiles, the Mosasaurus resembles them in so far as they all belong to the same class of Reptiles.

The idea of a lizard, adapted for living and moving with rapidity at the bottom of the water, is not readily conceived; but a careful study of the skeleton of the Mosasaurus reveals to us the secret of this anatomical mechanism. The vertebræ of the animal are concave in front and convex behind; they are attached by means of orbicular or arched articulations, which permitted it to execute easily movements of flexion in any direction. From the middle of the back to the extremity of the tail these vertebræ are deficient in the articular processes which support and strengthen the trunk of terrestrial vertebrated animals: they resemble in this respect the vertebræ of the Dolphins; an organisation necessary to render swimming easy. The tail, compressed laterally at the same time that it was thick in a vertical direction, constituted a straight rudder, short, solid, and of great power. An arched bone was firmly attached to the body of each caudal vertebra in the same manner as in Fishes, for the purpose of giving increased power to the tail; finally, the extremities of the animal could scarcely be called feet, but rather paddles, like those of the Ichthyosaurus, the Plesiosaurus, and the Whale. We see in Fig. 146 that the jaws are armed with numerous teeth, fixed in their sockets by an osseous base, both large and solid. Moreover, an altogether peculiar dental system occupies the vault of the palate, as in the case of certain Serpents and Fishes, where the teeth are directed backwards, like the barb of a hook, thus opposing themselves to the escape of prey. Such a disposition of the teeth sufficiently proves the destructive character of this Saurian.

The dimensions of this aquatic lizard, estimated at twenty-four feet, are calculated to excite surprise. But, as we have already seen, the Ichthyosauri and Teleosauri were of great dimensions, as were also the Iguanodon and Megalosaurus, which were ten times the size of living Iguanas. In all these colossal forms we can only see a difference of dimensions, the aggrandisement of a type; the laws which affected the organisation of all these beings remain unchanged, they were not errors of Nature--monstrosities, as we are sometimes tempted to call them--but simply types, uniform in their structure, and adapted by their dimensions to the physical conditions with which God had surrounded them.

In PLATE XXII. is represented an ideal view of the earth during the Upper Cretaceous period. In the sea swims the Mosasaurus; Molluscs, Zoophytes, and other animals peculiar to the period are seen on the shore. The vegetation seems to approach that of our days; it consists of Ferns and Cycadeæ (Pterophyllums), mingled with Palms, Willows, and some dicotyledons of species analogous to those of our present epoch. Algæ, then very abundant, composed the vegetation of the sea-shore.

We have said that the terrestrial flora of the Upper Cretaceous period was nearly identical with that of the Lower. The marine flora of these two epochs included some Algæ, Confervæ, and Naïadæ, among which may be noted the following species: Confervites fasciculatus, Chondrites Mantelli, Sargassites Hynghianus. Among the Naïadæ, Zosterites Orbigniana, Z. lineata, and several others.

The Confervæ are fossils which may be referred, but with some doubt, to the filamentous Algæ, which comprehend the great group of the Confervæ. These plants were formed of simple or branching filaments, diversely crossing each other; or subdivided, and presenting traces of transverse partitions.

The Chondrites are, perhaps, fossil Algæ, with thick, smooth branching fronds, pinnatifid, or divided into pairs, with smooth cylindrical divisions, and resembling Chondrus, Dumontia, and Halymenia among living genera.

The Sargassites, finally, have been vaguely referred to the genus Sargassum, so abundant in tropical seas. These Algæ are distinguished by a filiform, branched, or ramose stem, bearing foliaceous appendages, regular, often petiolate, and altogether like leaves, and globular vesicles, supported by a small stalk.

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The rocks which actually represent the Upper Cretaceous period divide themselves naturally into six series; but British and French geologists make some distinction: the former dividing them into 1, Maestricht and Faxoe beds, said not to occur in England; 2, White Chalk, with flints; 3, White Chalk, without flints; 4, Chalk Marl; 5, Upper Greensand; and 6, Gault. The latter four are divided by foreign geologists into 1, Turonian; 2, Senonian; 3, Danian.

The Gault is the lowest member of the Upper Cretaceous group. It consists of a bluish-black clay mixed with greensand, which underlies the Upper Greensand. Near Cambridge, where the Gault is about 200 feet thick, a layer of shells, bones, and nodules, called the “Coprolite Bed,” from nine inches to a foot thick, represents the Upper Greensand, and rests on the top of the Gault Clay. These nodules and fossils are extensively worked on account of the phosphatic matter they contain, and when ground and converted into superphosphate of lime they furnish a very valuable agricultural manure. The Gault attains a thickness of about 100 feet on the south-east coast of England. It extends into Devonshire, Mr. Sharpe considering the Black Down beds of that country as its equivalents. It shows itself in the Departments of the Pas-de-Calais, the Ardennes, the Meuse, the Aube, the Yonne, the Ain, the Calvados, and the Seine-Inférieure. It presents very many distinct mineral forms, among which two predominate: green sandstone and blackish or grey clays. It is important to know this formation, for it is at this level that the Artesian waters flow in the wells of Passy and Grenelle, near Paris.

The glaucous chalk, or Upper Greensand, which is represented typically in the departments of the Sarthe, of the Charente-Inférieure, of the Yonne and the Var, is composed of quartzose sand, clay, sandstone, and limestone. In this formation, at the mouth of the Charente, we find a remarkable bed, which has been described as a submarine forest. It consists of large trees with their branches imbedded horizontally in vegetable matter, containing kidney-shaped nodules of amber, or fossilised resin.

The Turonian beds are so named because the province of Touraine, between Saumur and Montrichard, possesses the best-developed type of this strata. The mineralogical composition of the beds is a fine and grey marly chalk, as at Vitry-le-François; of a pure white chalk, with a very fine grain, slightly argillaceous, and poor in fossils, in the Departments of the Yonne, the Aube, and the Seine-Inférieure; granular tufaceous chalk, white or yellowish, mixed with spangles of mica, and containing Ammonites, in Touraine and a part of the Department of the Sarthe; white, grey, yellow, or bluish limestone, inclosing Hippurites and Radiolites. In England the Lower Chalk passes also into Chalk Marl, with Ammonites, and then into beds known as the Upper Greensand, containing green particles of glauconite, mixed, in Hampshire and Surrey, with much calcareous matter. In the Isle of Wight this formation attains a thickness of 100 feet. The Senonian beds take their name from the ancient Senones. The city of Sens is in the centre of the best-characterised portion of this formation; Epernay, Meudon, Sens, Vendôme, Royau, Cognac, Saintes, are the typical regions of the formation in France. In the Paris basin, inclusive of the Tours beds, it attains a thickness of upwards of 1,500 feet, as was proved by the samples brought up, during the sinking of the Artesian well, at Grenelle, by the borings.

In its geographical distribution the Chalk has an immense range; fine Chalk of nearly similar aspect and composition being met with in all directions over hundreds of miles, alternating in its lower beds with layers of flints. In England the higher beds usually consist of a pure-white calcareous mass, generally too soft for building-stone, but sometimes passing into a solid rock.

The Danian beds, which occupy the summit of the scale in the Cretaceous formation, are finely developed at Maestricht, on the Meuse; and in the Island of Zeeland, belonging to Denmark; where they are represented by a slightly yellowish, compact limestone, quarried for the construction of the city of Faxoe. It is slightly represented in the Paris basin at Meudon, and Laversines, in the Department of the Oise, by a white and often rubbly limestone known as pisolitic limestone. In this formation Ammonites Danicus is found. The yellowish sandy limestone of Maestricht is referred to the Danian type. Besides Molluscs, Polyps, and Polyzoa (Bryozoa), this limestone contains remains of Fishes, Turtles, and Crocodiles. But what has rendered this rock so celebrated was that it contained the remains of the great animal of Mæstricht, the Mæsasaurus.

At the close of the geological period, whose natural physiognomy we have thus traced, Europe was still far from displaying the configuration which it now presents. A map of the period would represent the great basin of Paris (with the exception of a zone of Chalk), the whole of Switzerland, the greater part of Spain and Italy, the whole of Belgium, Holland, Prussia, Hungary, Wallachia, and Northern Russia, as one vast sheet of water. A band of Jurassic rocks still connected France and England at Cherbourg--which disappeared at a later period, and caused the separation of the British Islands from what is now France.

TERTIARY PERIOD.

A new organic creation makes its appearance in the Tertiary period; nearly all the animal life is changed, and what is most remarkable in this new development is the appearance, in larger numbers, of the great class of Mammifera.

During the Primary period, Crustaceans and Fishes predominated in the animal kingdom; in the Secondary period the earth was assigned to Reptiles; but during the Tertiary period the Mammals were kings of the earth; nor do these animals appear in small number, or at distant intervals of time; great numbers of these beings appear to have lived on the earth, and at the same moment; many of them being, so to say, unknown and undescribed.