Dr. Buckland describes eight distinct species, varying in size from a snipe to a cormorant. Of these, P. crassirostris (Fig. 105) and P. brevirostris (Fig. 106), were both discovered in the Lias of •Solenhofen. P. macronyx belongs to the Lias of Lyme Regis.

The Pterodactyle was, then, a reptile provided with wings somewhat resembling those of Bats, and formed, as in that Mammal, of a membrane which connected the body with the excessively elongated phalanges of the fourth finger, which served to expand the membrane that answered the purposes of a wing. The Pterodactyle of the Liassic period was, as we have seen, an animal of small size; the largest species in the older Lias beds did not exceed ten or twelve inches in length, or the size of a raven, while the later forms found fossil in the Greensand and Wealden beds must 'have measured more than sixteen feet between the tips of the expanded wings. On the other hand, its head was of enormous dimensions compared with the rest of the body. We cannot admit, therefore, that this animal could really fly, and, like a bird, beat the air. The membranous appendage which connected its long finger with its body was rather a parachute than a wing. It served to moderate the velocity of its descent when it dropped on its prey from a height. Essentially a climber, it could only raise itself by climbing up tall trees or rocks, after the manner of lizards, and throw itself thence to the ground, or upon the lower branches, by making use of its natural parachute. The ordinary position of the Pterodactyle was probably upon its two hind feet, the lower extremities being adapted for standing and moving on the ground, after the • manner of birds. Habitually, perhaps, itperched on trees; it could creep, or climb along rocks and cliffs, or suspend itself from trees, with the assistance of its claws and feet, after the manner of existing Bats. It is even probable, Dr. Buckland thought, that it had the power of swimming and diving, sa

THE LIAS.

common to reptiles, and possessed by the VampjTC Bat of the island of Benin. It is believed that the smaller species lived upon insects^ and the larger preyed upon fishes, upon which it could throw itself like the sea-gull. The most startling feature in the organisation of this animal is-the strange combination of two powerful wings attached to the body of a reptile. The imagination of the poets long dwelt on such a combination; the Dragon was a creation of their fancy, and it pla}Td a great part in fable and in pagan mythology. The Dragon,, or flying reptile, breathing fire and poisoning the air with his fiery breath, had, according to the fable, disputed with man the possession of the earth. Gods and demigods claimed, among their most famous exploits, the glory of having vanquished this powerful and redoubtable monster.

Among the animals of our epoch, only a single reptile is found provided with wings, or digital appendages analogous to the membranous wings of the bats, and which can be compared to the Pterodactyle. This is called the Dragon, one of the Draconidse, a family of Saurians, which has been described by Daudin, as distinguished by the first six ribs, instead of hooping round the abdomen, extending in nearly a straight line, and sustaining a prolongation of skin which forms a sort of wing analogous to that of the Pterodactyle. Independent of the four feet, this wing sustains the animal, like a parachute, as it leaps from branch to branch; but the creature has no power to beat the air with it as birds do when flying. This reptile lives in the forests of the hottest parts of Africa, and in some isles of the Indian Ocean, especially in Sumatra and Java. The only known species is that figured at page 238 (Fig. 107), which comes from the East Indies. What a strange population was that which occupied the earth at this stage of its history, when the waters were filled with creatures so-extraordinary as those whose history we have traced! Plesiosauri and Ichthyosauri filled the seas, upon the surface of which floated innumerable Ammonites in light skiffs, some of them as large as a. good-sized cart-wheel, while gigantic Turtles and Crocodiles crawled on the banks of the rivers and lakes. Only one genus of Mammals had yet appeared, but no birds; nothing broke the silence of the air^ if we except the breathing of the terrestrial reptiles and the flight of winged insects. The earth cooled progressively up to the Jurassic period, the rains lost their continuity and abundance, and the pressure of the atmosphere sensibly diminished. All these circumstances favoured

:238 THE WORLD BEFORE THE DELUGE.

the appearance and the multiplication of innumerable species of animals, whose singular forms then showed themselves on the earth. We can scarcely imagine the prodigious quantity of Molluscs and

Fig. 107.— Draco volans.

Zoophytes whose remains lie buried in the Jurassic rocks, forming entire strata of immense thickness and extent.

The same circumstances concurred to favour the production of plants. If the shores and seas of the period received such a terrible aspect from the formidable animals we have described, the vegetation which covered the land had also its peculiar character and appearance. Nothing that we know of in the existing scenery of the globe surpasses the rich vegetation which decorated the continents of the Jurassic period. A temperature still of great elevation, a

humid atmosphere, and, we have no reason to doubt, a brilliant sun, promoted the growth of a luxuriant vegetation, such as some of the tropical islands, with their burning temperature and maritime climate, can only give us an idea of, while it recalls some of the Jurassic types of vegetation. The elegant Voltzias of the Trias had disappeared, but the Horse-tails {Eqtcisefa) remained, whose slender and delicate stems rose erect in the air with their graceful panicles; the gigantic rushes also remained; and though the tree-ferns had lost their enormous dimensions of the Carboniferous age, they still preserved their fine and dehcately-cut leaves.

Alongside these vegetable families, which passed upwards from the preceding age, an entire family — the Cycads (Fig. 72, p. 168) — appear for the first time. They soon became numerous in genera, such as Zamites, Pterophyllum (Williamsonia), and Nilsonia. Among the species which characterise this age, we may cite the following, arranging them in families:—

FERNS. CYCADS. CONIFERS,

Odontopteris cycadea. Zamites distans. Taxodites.

Taumopteris Munsteri. Zamites heterophyllus. Pinites.

Camptopteris crenata. Zamites gracilis. Pterophyllum dubium. Nilsonia contigua. Nilsonia elegantissima. Nilsonia Sternbergii.

The Zamites seem to be forerunners of the Palms, which make their appearance in the following epoch; they were trees of elegant appearance, closely resembling the existing Zamias, which are trees of tropical America, and especially of the West India Islands; they were so numerous in species and in individuals that they seem to have formed, of themselves alone, one half of the forests during the period which engages our attention. The number of their fossilised species exceeds that of the living species. The trunk of the Zamites, simple and covered with scars left by the old leaves, supports a thick crown of leaves more than six feet in length, disposed in fan-like shape, arising from a common centre.

The Ptei'ophylhun (Williamsonia), formed great trees, of considerable elevation, and covered with large pinnated leaves from top to bottom. Their leaves, thin and membranous, were furnished with leaflets truncated at the sum.mit and traversed by fine nervures, not convergent, but abutting on the terminal truncated edge.

The Nilsonia,. finally, were Cycadeacese resembling the Ptero-

phyllum, but with thick and coriaceous leaves, and short leaflets contiguous to, and in part attached to the base; they were obtuse or nearly truncated at the summit, and would present nervures arched or confluent towards that summit.

The essential characters of the vegetation during the Liassic subperiod were:— i. The great predominance of the Cycadeaceae, thus continuing the development which commenced in the previous period, expanding into numerous genera belonging both to this

Fig. io8. — Millepora alcicornis. (Recent Coral.)

family and that of the Zamites and Nilsonia; 2. The existence among the Ferns of many genera with reticulated veins or nervures, and under forms of little variation, which scarcely show themselves in the more ancient formations.

On the opposite page (Plate XVI.) is an ideal landscape of the Liassic period; the trees and shrubs characteristic of the age are the elegant Pterophyllum, which appears in the extreme left of the picture, and the Zamites, which are recognisable by their thick and low trunk and fan-like tuft of foliage. The large horsetail, or Equisetum of this epoch, mingles with the great Tree-ferns and the Cypress, a Conifer aUied to those of our own age. Among animals,. we see the Pterodactyle specially represented. One of these reptiles

XVI.—Ideal Landscape of the Liassic Period.

OOLITIC SUB-PERIOD.

is seen in a state of repose, resting on its hind feet. The other is represented, not flying, after the manner of a bird, but throwing itself from a rock in order to seize upon a winged insect, the dragon-fly {Libelhda), the remains of which have been discovered, associated with the bones of the Pterodactyle, in the lithographic hraestone of Pappenheim and Solenhofen.

Oolitic Sub-period.

This period is so named because many of the limestones entering into the composition of the formations it comprises, consist almost entirely of an aggregation of rounded concretionary grains resembling, in outward appearance, the roe or eggs of fishes, and each of which contains a nucleus of sand, around which concentric layers of calcareous matter have accumulated; whence the name, from b)6v, egg, and Ai0os, sto7ie. The Oolite series is usually subdivided into three sections, the Lower, Middle, and Upper Oolite. These rocks form in England a band some thirty miles broad, ranging across the country from Yorkshire, in the north-east, to Dorset, in the south-west, but with a great diversity of mineral character, which has led to a further subdivision of the series, founded on the existence of particular strata in the central and south-western counties:—

Upper. Middle. I. Lower. I. Purbeck Beds. I. Coral Rag. 2. Combrash. 2.. Portland Stone and 2. Oxford Clay. Great Oolite & Forest

Sand. Marble. Stonesfield Slate. 3. Kimeridge Clay. Fuller's Earth. Inferior Oolite.

The alternations of clay and masses of limestone in the Liassic and Oolite formations impart some marked features to the outline of the scenery both of France and England: forming broad valleys, separated from each other by ranges of limestone hills of more or less elevation. In France, the Jura mountains are composed of the latter; in England, the slopes of this formation are more gentle — the valleys are intersected by brooks, and clothed with a rich vegetation; 4- it forms what is called a tame landscape, as compared with3- the wilder grandeur of the Primary rocks — it pleases more than it surprises. Ityields materials also, more useful than some of the5-older formations, numerous quarries being met with which furnish excellent building-materials, esoecially around Bath, where the stone, when

first quarried, is soft and easily worked, but becomes harder on exposure to the air. The annexed section (Fig. 109) will give some idea of the configuration which the stratification assumes, such as may be observed in proceeding from the north-west to the south-east, from Caermarthenshire to the banks of the Ouse.

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