  During the Primary Epoch our globe would appear to have been chiefly appropriated to beings which lived in the waters—above all, to the Crustaceans and Fishes; during the Secondary Epoch Reptiles seem to have been its prevailing inhabitants. Animals of this class assumed astonishing dimensions, and would seem to have multiplied in a most singular manner; they were, apparently, the kings of the earth. At the same time, however, that the animal kingdom thus developed itself, the vegetation lost much of its importance. Geologists have agreed among themselves to divide the Secondary epoch into three periods: 1, the Cretaceous; 2, the Jurassic; 3, the Triassic—a division which it is convenient to adopt. The Triassic, or New Red Period.This period has received the name of Triassic because the rocks of which it is composed, which are more fully developed in Germany than either in England or France, were called the Trias (or Triple Group), by German writers, from its division into three groups, as follows, in descending order:—
The following has been shown by Mr. Ed. Hull to be the general succession of the Triassic formation in the midland and north-western counties of England, where it attains its greatest vertical development, thinning away in the direction of the mouth of the Thames:—
New Red Sandstone.In this new phase of the revolutions of the globe, the animated beings on its surface differ much from those which belonged to the Primary epoch. The curious Crustaceans which we have described under the name of Trilobites have disappeared; the molluscous Cephalopods and Brachiopods are here few in number, as are the Ganoid and Placoid Fishes, whose existence also seems to have terminated during this period, and vegetation has undergone analogous changes. The cryptogamic plants, which reached their maximum in the Primary epoch, become now less numerous, while the Conifers experienced a certain extension. Some kinds of terrestrial animals have disappeared, but they are replaced by genera as numerous as new. For the first time the Turtle appears in the bosom of the sea, and on the borders of lakes. The Saurian reptiles acquire a great development; they prepare the way for those enormous Saurians, which appear in the following period, whose skeletons present such vast proportions, and such a strange aspect, as to strike with astonishment all who contemplate their gigantic, and, so to speak, awe-inspiring remains. The Variegated Sandstone, or Bunter, contains many vegetable, but few animal, remains, although we constantly find imprints of the footsteps of the Labyrinthodon. The lowest Bunter formation shows itself in France, in the Pyrenees, around the central plateau in the Var, and upon both flanks of the Vosges mountains. It is represented in south-western and central Germany, in Belgium, in Switzerland, in Sardinia, in Spain, in Poland, in the Tyrol, in Bohemia, in Moravia, and in Russia. M. D’Orbigny states, from his own observation, that it covers vast surfaces in the mountainous regions of Bolivia, in South America. It is recognised in the United States, in Columbia, in the Great Antilles, and in Mexico. The Bunter in France is reduced to the variegated sandstone, except around the Vosges, in the Var, and the Black Forest, where it is accompanied by the Muschelkalk. In Germany it furnishes building-stone of excellent quality; many great edifices, in particular the cathedrals, so much admired on the Rhine—such, for example, as those of Strasbourg and Fribourg—are constructed of this stone, the sombre tints of which singularly relieve the grandeur and majesty of the Gothic architecture. Whole cities in Germany are built of the brownish-red stones drawn from its mottled sandstone quarries. In “Different members of the group rest in England, in some region or other,” says Lyell, “on almost every principal member of the PalÆozoic series, on Cambrian, Silurian, Devonian, Carboniferous, and Permian rocks; and there is evidence everywhere of disturbance, contortion, partial upheaval into land, and vast denudations which the older rocks underwent before and during the deposition of the successive strata of the New Red Sandstone group.” (“Elements of Geology,” p. 439.) The Muschelkalk consists of beds of compact limestone, often greyish, sometimes black, alternating with marl and clay, and commonly containing such numbers of shells that the name of shelly limestone (Muschelkalk) has been given to the formation by the Germans. The beds are sometimes magnesian, especially in the lower strata, which contain deposits of gypsum and rock-salt. The seas of this sub-period, which is named after the innumerable masses of shells inclosed in the rocks which it represents, included, besides great numbers of Mollusca, Saurian Reptiles of twelve different Fig. 81.—Ceratites nodosus. (Muschelkalk.) Among the shells characteristic of the Muschelkalk period, we mention Natica Gaillardoti, Rostellaria antiqua, Lima striata, Avicula socialis, Terebratula vulgaris, Turbonilla dubia, Myophoria vulgaris, Nautilus hexagonalis, and Ceratites nodosus. The Ceratites, of which a species is here represented (Fig. 81), form a genus closely allied to the Ammonites, which seem to have played such an important part in the ancient seas, but which have no existence in those of our era, either in species or even in genus. This Ceratite is found in the Muschelkalk of Germany, a formation which has no equivalent in England, but which is a compact greyish limestone underlying the saliferous rocks in Germany, and including beds of dolomite with gypsum and rock-salt. The Mytilus or Mussel, which properly belonged to this age, are acephalous (or headless) Molluscs with elongated triangular shells, of which there are many species found in our existing seas. Lima, Myophoria, Posidonia, and Avicula, are acephalous Molluscs of the same period. The two genera Natica and Rostellaria belong to the Gasteropoda, and are abundant in the Muschelkalk in France, Germany, and Poland. Fig. 82.—Encrinus liliiformis. Among the Echinoderms belonging to this period may be mentioned Encrinus moniliformis and E. liliiformis, or lily encrinite (Fig. 82), whose remains, constituting in some localities whole beds of rock, show the slow progress with which this zoophyte formed beds of limestone in the clear seas of the period. To these may be added, among the Mollusca, Avicula subcostata and Myophoria vulgaris. In the Muschelkalk are found the skull and teeth of Placodus gigas, a reptile which was originally placed by Agassiz among the class of Fishes; but more perfect specimens have satisfied Professor Owen that it was a Saurian Reptile. It may be added, that the presence of a few genera, peculiar to the Primary epoch, which entirely disappeared during the sub-period, Fig. 83.—Labyrinthodon restored. One-twentieth natural size. The seas, then, contained a few Reptiles, probably inhabitants of the banks of rivers, as Phytosaurus, Capitosaurus, &c., and sundry Fishes, as Sphoerodus and Pycnodus. In this sub-period we shall say nothing of the Land-Turtles, which for the first time now appear; but, we should note, that at the Bunter period a gigantic Reptile appears, on which the opinions of geologists were for a long while at variance. In the argillaceous rocks of the Muschelkalk period imprints of the foot of some animal were discovered in the sandstones of Storeton Hill, in Cheshire, and in the New Red Sandstone of parts of Warwickshire, as well as in Thuringia, and Hesseburg in Saxony, which very much resembled the impression that might be made in soft clay by the outstretched fingers and thumb of a human hand. These traces were made by a species of Reptile furnished with four feet, the two fore-feet being much broader than the hinder two. The head, pelvis, and scapula only of this strange-looking animal have been found, but these are considered to have belonged to a gigantic air-breathing reptile closely connected with the Batrachians. It is thought that the head was not naked, but protected by a bony cushion; that its jaws were armed with conical teeth, of great strength and of a complicated structure. This curious and uncouth-looking creature, of which the woodcut Fig. 83 is a restoration, has been named the Cheirotherium, or Labyrinthodon, from the complicated arrangement of the cementing layer of the teeth. (See also Fig. 1, p. 12.) Another Reptile of great dimensions—which would seem to have been intended to prepare the way for the appearance of the enormous Saurians which present themselves in the Jurassic period—was the Nothosaurus, a species of marine Crocodile, of which a restoration has been attempted in Plate XIII. opposite. XIII.—Ideal Landscape of the Muschelkalk Sub-period. It has been supposed, from certain impressions which appear in the Keuper sandstones of the Connecticut river in North America, M. Ad. Brongniart places the commencement of dicotyledonous gymnosperm plants in this age. The characteristics of this Flora consist in numerous Ferns, constituting genera now extinct, such as Anomopteris and Crematopteris. The true Equiseta are rare in it. The Calamites, or, rather, the Calamodendra, abound. The gymnosperms are represented by the genera Conifer, Voltzia, and Haidingera, Among the species of plants which characterise this formation, we may mention Neuropteris elegans, Calamites arenaceus, Voltzia heterophylla, Haidingera speciosa. The Haidingera, belonging to the tribe of AbietinÆ, were plants with large leaves, analogous to those of our Damara, growing close together, and nearly imbricated, as in the Araucaria. Their fruit, which are cones with rounded scales, are imbricated, and have only a single seed, thus bearing out the strong resemblance which has been traced between these fossil plants, and the Damara. Fig. 84.—Branch and cone of Voltzia restored. The Voltzias (Fig. 84), which seem to have formed the greater part of the forests were a genus of CupressinaceÆ, now extinct, which are well characterised among the fossil Conifers of the period. The alternate spiral leaves, forming five to eight rows sessile, that is, sitting close to the branch and drooping, have much in them analogous to the Cryptomerias. Their fruit was an oblong cone with scales, loosely imbricated, cuneiform or wedge-shaped, and, commonly, composed of from three to five obtuse lobes. In Fig. 84 we have a part of the stem, a branch with leaves and cone. In his “Botanic Geography,” M. Lecoq thus describes the vegetation of the ancient world in the first period of the Triassic age: “While the variegated sandstone and mottled clays were being slowly deposited in regular beds by the waters, magnificent Ferns still exhibited their light and elegantly-carved leaves. Divers Protopteris and majestic Neuropteris associated themselves in extensive forests, where vegetated also the Crematopteris typica of Schimper, the Anomopteris Mongeotii of Brongniart, and the pretty Trichomanites myriophyllum (GÖppert). The Conifers of this epoch attain a very considerable development, and would form graceful forests of green trees. Elegant monocotyledons, representing the forms of tropical countries, seem to show themselves for the first time, the Yuccites Vogesiacus of Schimper constituted groups at once thickly serried and of great extent. “A family, hitherto doubtful, appears under the elegant form of Nilssonia Hogardi, Schimp.; Ctenis Hogardi, Brongn. It is still seen in the Zamites Vogesiacus, Schimp.; and the group of the Cycads sharing at once in the organisation of the Conifers and the elegance of the Palms, now decorate the earth, which reveals in these new forms its vast fecundity. (See Fig. 72, p. 168.) “Of the herbaceous plants which formed the undergrowth of the forests, or which luxuriated in its cool marshes, the most remarkable is the Ætheophyllum speciosum, Schimp. Their organisation approximates The engraving at page 191 (Plate XIII.) gives an idealised picture of the plants and animals of the period. The reader must imagine himself transported to the shores of the Muschelkalk sea at a moment when its waves are agitated by a violent but passing storm. The reflux of the tide exposes some of the aquatic animals of the period. Some fine Encrinites are seen, with their long flexible stems, and a few Mytili and TerebratulÆ. The Reptile which occupies the rocks, and prepares to throw itself on its prey, is the Nothosaurus. Not far from it are other reptiles, its congeners, but of a smaller species. Upon the dune on the shore is a fine group of the trees of the period, that is, of Haidingeras, with large trunks, with drooping branches and foliage, of which the cedars of our own age give some idea. The elegant Voltzias are seen in the second plane of this curtain of verdure. The Reptiles which lived in these primitive forests, and which would give to it so strange a character, are represented by the Labyrinthodon, which descends towards the sea on the right, leaving upon the sandy shore those curious tracks which have been so wonderfully preserved to our days. The footprints of the reptilian animals of this period prove that they walked over moist surfaces; and, if these surfaces had been simply left by a retiring tide, they would generally have been obliterated by the returning flood, in the same manner that is seen every day on our own sandy shores. It seems more likely that the surfaces, on which fossil footprints are now found, were left bare by the summer evaporation of a lake; that these surfaces were afterwards dried by the sun, and the footprints hardened, so as to ensure their preservation, before the rising waters brought by flooded muddy rivers again submerged the low flat shores and deposited new layers of salt, just as they do at the present day round the Dead Sea and the Salt Lake of Utah. XIV.—Ideal Landscape of the Keuper Sub-period. Keuper Sub-period.The formation which characterises the Keuper, or saliferous period, is of moderate extent, and derives the latter name from the salt deposits it contains. These rocks consist of a vast number of argillaceous and marly beds, variously coloured, but chiefly red, with tints of yellow and green. These are the colours which gave the name of variegatea (Poikilitic) to the series. The beds of red marl often alternate with sandstones, which are also variegated in colour. As subordinate rocks, we find in this formation some deposits of a poor pyritic coal and of gypsum. But what especially characterises the formation are the important deposits of rock-salt which are included in it. The saliferous beds, often twenty-five to forty feet thick, alternate with beds of clay, the whole attaining a thickness of 160 yards. In Germany in WÜrtemberg, in France at Vic, at Dieuze, and at ChÂteau-Salins, the rock-salt of the saliferous formation has become an important branch of industry. In the Jura, salt is extracted from the water charged with chlorides, which issues from this formation. Some of these deposits are situated at great depths, and cannot be reached without very considerable labour. The salt-mines of Wieliczka, in Poland, for example, can be procured on the surface, or by galleries of little depth, because the deposit belongs to the Tertiary period; but the deposits of salt, in the Triassic age, lie so much deeper, as to be only approachable by a regular process of mining by galleries, and the ordinary mode of reaching the salt is by digging pits, which are afterwards filled with water. This water, charged with the salt, is then pumped up into troughs, where it is evaporated, and the crystallised mineral obtained. What is the origin of the great deposits of marine salt which occur in this formation, and which always alternate with thin beds of clay or marl? We can only attribute them to the evaporation of vast quantities of sea-water introduced into depressions, cavities, or gulfs, which the sandy dunes afterwards separated from the great open sea. In Plate XIV. an attempt is made to represent the natural fact, which must have been of frequent recurrence during the saliferous period, to form the considerable masses of rock-salt which are now found in the rocks of the period. On the right is the sea, with a dune of considerable extent, separating it from a tranquil basin of smooth water. At intervals, and from various causes, the sea, clearing the dune, enters and fills the basin. We may even suppose that a gulf There is in the delta of the Indus a singular region, called the Runn of Cutch, which extends over an area of 7,000 square miles, which is neither land nor sea, but is under water during the monsoons, and in the dry season is incrusted, here and there, with salt about an inch thick, the result of evaporation. Dry land has been largely increased here, during the present century, by subsidence of the waters and upheavals by earthquakes. “That successive layers of salt may have been thrown down one upon the other on many thousand square miles, in such a region, is undeniable,” says Lyell. “The supply of brine from the ocean is as inexhaustible as the supply of heat from the sun. The only assumption required to enable us to explain the great thickness of salt in such an area, is the continuance for an indefinite period of a subsidence, the country preserving all the time a general approach to horizontally.” The observations of Mr. Darwin on the atolls of the Pacific, prove that such a continuous subsidence is probable. Hugh Miller, after ably discussing various spots of earth where, as in the Runn of Cutch, evaporation and deposit take place, adds: “If we suppose that, instead of a barrier of lava, sand-bars were raised by the surf on a flat arenaceous coast, during a slow and equable sinking of the surface, the waters of the outer gulf might occasionally topple over the bar and supply a fresh brine when the first stock had been exhausted by evaporation.” Professor Ramsay has pointed out that both the sandstones and By the silting up of such lakes with sediment, and the gradual evaporation of their waters under favourable conditions, such as increased heat and diminished rainfall—where the lakes might cease to have an outflow into the sea and the loss of water by evaporation would exceed the amount flowing into them—the salt or salts contained in solution would, by degrees, become concentrated and finally precipitated. In this way the great deposits of rock-salt and gypsum, common in the Keuper formation, may be accounted for. Subsequently, by increase of rainfall or decrease of heat, and sinking of the district, the waters became comparatively less salt again; and a recurrence of such conditions lasted until the close of the Keuper period, when a partial influx of the sea took place, and the RhÆtic beds of England were deposited. The red colour of the New Red Sandstones and marls is caused by peroxide of iron, which may also have been carried into the lakes in solution, as a carbonate, and afterwards converted into peroxide by contact with air, and precipitated as a thin pellicle upon the sedimentary grains of sandy mud, of which the Triassic beds more or less consist. Professor Ramsay further considers that all the red-coloured strata of England, including the Permian, Old Red Sandstone, and even the Old Cambrian formation, were deposited in lakes or inland waters. There is little to be said of the animals which belong to the Saliferous period. They are nearly the same as those of the Muschelkalk, &c. Fig. 85.—Pecten orbicularis. Among the most abundant of the shells belonging to the upper Trias, in all the countries where it has been examined, are the Avicula, Cardium, and Pecten, one of which is given in Fig. 85. Foraminifera are numerous in the Keuper marls. The remains of land-plants, and the peculiarities of some of the reptiles of the Keuper period, tend to confirm the opinion of Professor Ramsay, that the strata were deposited in inland salt-lakes. In the Keuper period the islands and continents presented few The Pterophyllum JÄgeri and P. MÜnsteri represented the Cycads, the Taxodites MÜnsterianus represented the Conifers, and, finally, the trunk of the Calamites was covered with a creeping plant, having elliptical leaves, with a re-curving nervature borne upon its long petioles, and the fruit disposed in bunches; this is the Preissleria antiqua, a doubtful monocotyledon, according to Brongniart, but M. Unger places it in the family of Smilax, of which it will thus be the earliest representative. The same botanist classes with the canes a marsh-plant very common in this period, the PalÆoxyris MÜnsteri, which Brongniart classes with the Preissleria among his doubtful Monocotyledons. The vegetation of the latter part of the Triassic period is thus characterised by Lecoq, in his “Botanical Geography”: “The cellular “What a singular aspect these ancient rocks would present, if we add to them the forest-trees Pterophyllum and the Zamites of the fine family of CycadeaceÆ, and the Conifers, which seem to have made their appearance in the humid soil at the same time! “It is during this epoch, while yet under the reign of the dicotyledonous angiosperms, that we discover the first true monocotyledons. The Preissleria antiqua, with its long petals, drooping and creeping round the old trunks, its bunches of bright-coloured berries like the Smilax of our own age, to which family it appears to have belonged. Besides, the Triassic marshes gave birth to tufts of PalÆoxyris MÜnsteri, a cane-like species of the GramineÆ, which, in all probability, cheered the otherwise gloomy shore. “During this long period the earth preserved its primitive vegetation; new forms are slowly introduced, and they multiply slowly. But if our present types of vegetation are deficient in these distant epochs, we ought to recognise also that the plants which in our days represent the vegetation of the primitive world are often shorn of their grandeur. Our EquisetaceÆ and LycopodiaceÆ are but poor representatives of the Lepidodendrons; the Calamites and Asterophyllites had already run their race before the epoch of which we write.” The principal features of Triassic vegetation are represented in Plate XIV., page 198. On the cliff, on the left of the ideal landscape, the graceful stems and lofty trees are groups of Calamites arenaceus; below are the great “horse-tails” of the epoch, Equisetum columnare, a slender tapering species, of soft and pulpy consistence, which, rising erect, would give a peculiar physiognomy to the solitary shore. The Keuper formation presents itself in Europe at many points, It appears again in Switzerland and in Germany, in the canton of Basle, in Argovia, in the Grand Duchy of WÜrtemberg, in the Tyrol, and in Austria, where it gives its name to the city of Salzburg. In the British Islands the Keuper formation commences in the eastern parts of Devonshire, and a band, more or less regular, extends into Somersetshire, through Gloucestershire, Worcestershire, Warwick, Leicestershire, Nottinghamshire, to the banks of the Tees, in Yorkshire, with a bed, independent of all the others in Cheshire, which extends into Lancashire. “At Nantwich, in the upper Trias of Cheshire,” Sir Charles Lyell states, “two beds of salt, in great part unmixed with earthy matter, attain the thickness of 90 or 100 feet. The upper surface of the highest bed is very uneven, forming cones and irregular figures. Between the two masses there intervenes a bed of indurated clay traversed by veins of salt. The highest bed thins off towards the south-west, losing fifteen feet of its thickness in the course of a mile, according to Mr. Ormerod. The horizontal extent of these beds is not exactly known, but the area containing saliferous clay and sandstones is supposed to exceed 150 miles in diameter, while the total thickness of the Trias in the same region is estimated by Mr. Ormerod at 1,700 feet. Ripple-marked sandstones and the footprints of animals are observed at so many levels, that we may safely assume the whole area to have undergone a slow and gradual depression during the formation of the New Red Sandstone.” Not to mention the importance of salt as a source of health, it is in Great Britain, and, indeed, all over the world where the saliferous rocks exist, a most important branch of industry. The quantity of the mineral produced in England, from all sources, is between 5,000 and 6,000 tons annually, and the population engaged in producing the mineral, from sources supposed to be inexhaustible, is upwards of 12,000. Fig. 86.—Productus Martini. The lower Keuper sandstones, which lie at the base of the series of red marls, frequently give rise to springs, and are in consequence called “water-stones,” in Lancashire and Cheshire. Fig. 87.—Patella vulgata. In following the grand mountainous slopes of the Alps and Carpathians we discover the saliferous rocks by this remarkable accumulation of AviculÆ. The same facies presents itself under identical conditions in Syria, in India, in New Caledonia, in New Zealand, and in Australia. It is not the least curious part of this period, that it presents, on one side of the site of the Alps, which were not yet raised, an immense accumulation of sediment, charged with gypsum, rock-salt, &c., without organic remains; while beyond, a region presents itself equally remarkable for the extraordinary accumulation of the remains of marine Mollusca. Among these were Myophoria lineata, which is often confounded with Trigonia, and Stellispongia variabilis. France at this period was still the skeleton of what it has since become. A map of that country represents the metamorphic rocks occupying the site of the Alps, the CÉvennes, and the Puy-de-DÔme, the country round Nantes, and the Islands of Brittany. The Primary rocks reach the foot of the Pyrenees, the Cotentin, the Vosges, and the Eifel Mountains. Some bands of coal stretch away from Valenciennes to the Rhine, and on the north of the Vosges, these mountains themselves being chiefly composed of Triassic rocks. RHÆTIC, OR PENARTH SUB-PERIOD.The attention of geologists has been directed within the last few years, more especially, to a series of deposits which intervene between the New Red Marl of the Trias, and the blue argillaceous limestones and shales of the Lower Lias. The first-mentioned beds, although they attain no great thickness in this country, nevertheless form a well-defined and persistent zone of strata between the unfossiliferous Triassic marls and the lower Liassic limestone with Ostrea Liassica and Ammonites planorbis, A. angulatus and A. Bucklandi; being everywhere characterised by the presence of the same groups of organic remains, and the same general lithological character of the beds. These last may be described as consisting of three sub-divisions, the lowermost composed of alternations of marls, clays, and marly limestones in the lower part, forming a gradual passage downwards into the New Red Marls upon which they repose. 2. A middle group of black, thinly laminated or paper-like shales, with thin layers of indurated limestone, and crowded in places with Pecten Valoniensis, Cardium RhÆticum, Avicula contorta, and other characteristic shells, as well as by the presence, nearly always, of a remarkable bed, which is commonly known as the “Bone-bed.” This thin band of stone, which is so well known at Aust, Axmouth, Westbury-on-Severn, and elsewhere, is a brecciated or conglomerated band of variable thickness which, sometimes a sandstone and sometimes a limestone, is always more or less composed of the teeth, scales, and bones of numerous genera of Fishes and Saurians, together with their fossilised excrement, which will be more fully and subsequently described under the name of Coprolites, under the Liassic period. The molar tooth of a small predaceous fossil mammal of the Microlestes family (?????, little; ??st??, beast), whose nearest living representative appears to be some of the HypsiprymnidÆ or Kangaroo Rats, has been found by Mr. Dawkins in some grey marls underlying the bone-bed on the sea-shore at Watchett, in Somersetshire; affording the earliest known trace of a fossil mammal in the The uppermost sub-division includes certain beds of white and cream-coloured limestone, resembling in appearance the smooth fracture and closeness of texture of the lithographic limestone of Solenhofen, and which, known to geologists and quarrymen under the name “white lias,” given to it by Dr. William Smith, was formerly always considered to belong to, and was included in, the Lias proper. The most remarkable bed in this zone is one of only a few inches in thickness, but it has long been known to collectors, and sought after under the name of Cotham Marble or Landscape Stone, the latter name having reference to the curious dendritic markings which make their appearance on breaking the stone at right angles to its bedding, bearing a singular resemblance to a landscape with trees, water, &c.; while the first name is that derived from its occurrence abundantly at Cotham, in the suburbs of Bristol, where the stone was originally found and noticed. This band of stone is interesting in another respect, because it sometimes shows by its uneven, eroded, and water-worn upper surface, that an interval took place soon after it had been deposited, when the newly-formed stone became partially dissolved, eroded, or worn away by water, before the stratum next in succession was deposited upon it. The same phenomenon is displayed, in a more marked degree, in the uppermost limestone or “white lias” bed of the series, which not only shows an eroded surface, but the holes made by boring Molluscs, exactly as is produced at the present day by the same class of animals, which excavate holes in the rocks between high and low-water marks, to serve for their dwelling-places, and as a protection from the waves to their somewhat delicate shells. The “White Lias” of Smith is the equivalent of the Koessen beds which immediately underlie the Lower Lias of the Swabian Jura, and have been traced for a hundred miles, from Geneva to the environs of Vienna; and, also, of the Upper St. Cassian beds, which are so called from their occurrence at St. Cassian in the Austrian Alps. The general character of the series of strata just described, is that The RhÆtic beds of Europe were, as a whole, formed under very different conditions in different areas. The thickness of the strata and the large and well-developed fauna (chiefly Mollusca) indicate that the RhÆtic strata of Lombardy, and other parts of the south and east of Europe, were deposited in a broad open ocean. On the other hand, the comparatively thin beds of this age in England and north-western Europe, the fauna of which, besides being poor in genera and species, consists of small and dwarfed forms, point to the conclusion that they were in great part deposited in shallow seas and in estuaries, or in lagoons, or in occasional salt lakes, under conditions which lasted for a long period. In consequence of the importance they assume in Lombardy (the ancient RhÆtia), the name “RhÆtic Beds” has been given to these strata by Mr. Charles Moore; Dr. Thomas Wright has proposed the designation “Avicula Contorta Zone,” from the plentiful occurrence of that shell in the black shales forming the well-marked middle zone, and which is everywhere present where this group of beds is found; Jules Martin and others have proposed the term “Infra-lias,” or “Infra-liassic strata;” while the name “Penarth Beds” has been assigned to these deposits in this country by Mr. H. W. Bristow, at the suggestion of Sir Roderick Murchison, in consequence of their conspicuous appearance and well-exposed sections in the bold headlands and cliffs of that locality, in the British Channel, west of Cardiff. A fuller description of these beds will be found in the Reports of the Bath Meeting of the British Association (1864), by Mr. Bristow; also in communications to the Geological Magazine, for 1864, by MM. Bristow and Dawkins; JURASSIC PERIOD.This period, one of the most important in the physical history of the globe, has received its name from the Jura mountains in France, the Jura range being composed of the rocks deposited in the seas of the period. In the term Jurassic, the formations designated as the “Oolite” and “Lias” are included, both being found in the Jura mountains. The Jurassic period presents a very striking assemblage of characteristics, both in its vegetation and in the animal remains which belong to it; many genera of animals existing in the preceding age have disappeared, new genera have replaced them, comprising a very specially organised group, containing not less than 4,000 species. The Jurassic period is sub-divided into two sub-periods: those of the Lias and the Oolite. The Liasis an English provincial name given to an argillaceous limestone, which, with marl and clay, forms the base of the Jurassic formation, and passes almost imperceptibly into the Lower Oolite in some places, where the Marlstone of the Lias partakes of the mineral character, as well as the fossil remains of the Lower Oolite; and it is sometimes treated of as belonging to that formation. “Nevertheless, the Lias may be traced throughout a great part of Europe as a separate and independent group, of considerable thickness, varying from 500 to 1,000 feet, containing many peculiar fossils, and having a very uniform lithological aspect.” 1. Upper Lias Clay, consists of blue clay, or shale, containing nodular bands of claystones at the base, crowded with Ammonites serpentinus, A. bifrons, Belemnites, &c. 2. The Middle Lias, commonly known as the Marlstone, is surmounted by a bed of oolitic ironstone, largely worked in Leicestershire and in the north of England as a valuable ore of iron. The underlying marls and sands, the latter of which become somewhat argillaceous below, form beds from 200 to 300 feet thick in Dorsetshire and Gloucestershire; the fossils are Ammonites margaritaceus, A. spinatus, Belemnites tripartitus. The upper rock-beds, especially the bed of ironstone on the top, is generally remarkably rich in fossils. Fig. 88.—GryphÆa incurva. 3. Lower Lias (averaging from 600 to 900 feet in thickness) consists, in the lower part, of thin layers of bluish argillaceous limestone, alternating with shales and clays; the whole overlaid by the blue clay of which the lower member of the Liassic group usually consists. This member of the series is well developed in Yorkshire, at Lyme Regis and Charmouth in Dorsetshire, and generally over the South-West and Midland Counties of England. GryphÆa incurva (Fig. 88), with sandy bands, occurs at the base, in addition to which we find Ammonites planorbis Bucklandi, A. Ostrea liassica, Lima gigantea, Ammonites Bucklandi, &c., in the lower limestones and shales. Above the clay are yellow sands from 100 to 200 feet thick, underlying the limestone of the Inferior Oolite. These sands were, until lately, In France the Lias abounds in the Calvados, in Burgundy, Lorraine, Normandy, and the Lyonnais. In the Vosges and Luxembourg, M. Elie de Beaumont states that the Lias containing GryphÆa incurva and Lima gigantea, and some other marine fossils, becomes arenaceous; and around the Harz mountains, in Westphalia and Bavaria, in its lower parts the formation is sandy, and is sometimes a good building-stone. “In England the Lias constitutes,” says Professor Ramsay, “a well-defined belt of strata, running continuously from Lyme Regis, on the south-west, through the whole of England, to Yorkshire on the north-east, and is an extensive series of alternating beds of clay, shale, and limestone, with occasional layers of jet in the upper part. The unequal hardness of the clays and limestones of the Liassic strata causes some of its members to stand out in the distinct minor escarpments, often facing the west and north-west. The Marlstone forms the most prominent of these, and overlooks the broad meadows of the lower Lias-clay, that form much of the centre of England.” In Scotland there are few traces of the Lias. Zoophytes, Mollusca, and Fishes of a peculiar organisation, but, above all, Reptiles of extraordinary size and structure gave to the sea of the Liassic period an interest and features quite peculiar. Well might Cuvier exclaim, when the drawings of the Plesiosaurus were sent to him: “Truly this is altogether the most monstrous animal that has yet been dug out of the ruins of a former world!” In the whole of the English Lias there are about 243 genera, and 467 species of fossils. The whole series has been divided into zones characterised by particular Ammonites, which are found to be limited to them, at least locally. Fig. 89.—Pentacrinites Briareus. Half natural size. Among the Echinodermata belonging to the Lias we may cite Asterias lumbricalis and PalÆocoma Furstembergii, which constitutes a genus not dissimilar to the star-fishes, of which its radiated form reminds us. The Pentacrinites, of which Pentacrinites Briareus is a type, ornaments many collections by its elegant form, and is represented in Figs. 79 and 89. It belongs to the order of Crinoidea, which is represented at the present time by a single living species, Pentacrinus caput-MedusÆ, one of the rare and delicate Zoophytes of the Caribbean sea. Oysters (Ostrea) made their appearance in the Muschelkalk of the last period, but only in a small number of species; they increased greatly in importance in the Liassic seas. Shells are the only traces which remain of the Ammonites. We have no exact knowledge of the animal which occupied and built them. The attempt at restoration, as exhibited in Fig. 91, will probably convey a fair idea of the Ammonite when living. We assume that it resembled the Nautilus of modern times. What a curious aspect these early seas must have presented, covered by myriads of these Molluscs of all sizes, swimming about in eager pursuit of their prey! Fig. 90.—Ammonites Turneri, from the Lower Lias. The Ammonites of the Jurassic age present themselves in a great variety of forms and sizes; some of them of great beauty. Ammonites bifrons, A. Noditianus, A. bisulcatus, A. Turneri (Fig. 90), and A. margaritatus, are forms characteristic of the Lias. Fig. 91.—Ammonite restored. The Belemnites, molluscous Cephalopods of a very curious organisation, appeared in great numbers, and for the first time, in the Jurassic seas. Of this Mollusc we only possess the fossilised internal “bone,” analogous to that of the modern cuttle-fish and the calamary of the present seas. This simple relic is very far from giving us an exact idea of what the animal was to which the name of Belemnite has been given (from ?e?e???, a dart) from their supposed resemblance to the head of a javelin. The slender cylindrical bone, the only vestige remaining to us, was merely the internal skeleton of the Fig. 92.—Belemnite restored. The beaks, or horny mandibles of the mouth, which the Belemnite possessed in common with the other naked Cephalopoda, are represented in Fig. 78, p. 181. As Sir H. De la Beche has pointed out, the destruction of the animals whose remains are known to us by the name of Belemnites was exceedingly great when the upper part of the Lias of Lyme Regis was deposited. Multitudes seem to have perished almost simultaneously, and millions are entombed in a bed beneath Golden Cap, a lofty cliff between Lyme Regis and Bridport Harbour, as well as in the upper Lias generally. Among the Belemnites characteristic of the Liassic period may be cited B. acutus (Fig. 93), B. pistiliformis, and B. sulcatus. Fig. 93.—Belemnites acutus. The seas of the period contained a great number of the fishes called Ganoids; which are so called from the splendour of the hard and enamelled scales, which formed a sort of defensive armour to protect their bodies. Lepidotus gigas was a fish of great size belonging to this age. A smaller fish was the Tetragonolepis, or Æchmodus Buchii. The Acrodus nobilis, of which the teeth are still preserved, and popularly known by the name of fossil leeches, was a fish of which an entire skeleton has never been met with. Neither are we better informed as to the Hybodus reticulatus. The bony spines, which form the anterior part of the dorsal fin of this fish, had long been an object of curiosity to geologists, under the general name of Ichthyodorulites, before they were known to be fragments of the fin of the Hybodus. The Ichthyodorulites were supposed by some naturalists to be the jaw of some animal—by others, weapons like those of the living Fig. 94.—Ichthyosaurus communis. Let us hasten to say, however, that these are not the beings that characterised the age, and were the salient features of the generation of animals which existed during the Jurassic period. These distinguishing features are found in the enormous reptiles with lizard’s head, crocodile’s conical teeth, the trunk and tail of a quadruped, whale-like paddles, and the double-concave vertebrÆ of fishes; and this strange form, on such a gigantic scale that even their inanimate remains are examined with a curiosity not unmixed with awe. The country round Lyme Regis, in Dorsetshire, has long been celebrated for the curious fossils discovered in its quarries, and preserved in the muddy accumulations of the sea of the Liassic period. The country is hilly—“up one hill and down another,” is a pretty correct provincial description of the walk from Bridport to Lyme Regis—where some of the most frightful creatures the living world has probably ever In 1811 a country girl, who made her precarious living by picking up fossils for which the neighbourhood was famous, was pursuing her avocation, hammer in hand, when she perceived some bones projecting a little out of the cliff. Finding, on examination, that it was part of a large skeleton, she cleared away the rubbish, and laid bare the whole creature imbedded in the block of stone. She hired workmen to dig out the block of Lias in which it was buried. In this manner was the first of these monsters brought to light: “a monster some thirty feet long, with jaws nearly a fathom in length, and huge saucer-eyes; which have since been found so perfect, that the petrified lenses have been split off and used as magnifiers,” as a writer in All the Year Round assures us. Fig. 95.—Head of Ichthyosaurus platydon. In Fig. 95 the head of I. platydon is represented. As in the Saurians, the openings of the nostrils are situated near the anterior angle of the orbits of the eyes, while those of the Crocodile are near the snout; but, on the other hand, in its osteology and its mode of dentition it nearly resembles the Crocodile; the teeth are pointed and conical—not, however, set in deep or separate sockets, but only implanted in a long and deep continuous groove hollowed in the bones of the jaw. These strong jaws have an enormous opening; for, in some instances, they have been found eight feet in length and armed with 160 teeth. Let us add that teeth lost through the voracity of the animal, or in contests with other animals, could be renewed The eyes of this marine monster were much larger than those of any animal now living; in volume they frequently exceed the human head, and their structure was one of their most remarkable peculiarities. In front of the sclerotic coat or capsule of the eye there is an annular series of thin bony plates, surrounding the pupil. This structure, which is now only met with in the eyes of certain turtles, tortoises, and lizards, and in those of many birds, could be used so as to increase or diminish the curvature of the transparent cornea, and thus increase or diminish the magnifying power, according to the requirements of the animal—performing the office, in short, of a telescope or microscope at pleasure. The eyes of the Ichthyosaurus were, then, an optical apparatus of wonderful power and of singular perfection, enabling the animal, by their power of adaptation and intensity of vision, to see its prey far and near, and to pursue it in the darkness and in the depths of the sea. The curious arrangement of bony plates we have described furnished, besides, to its globular eye, the power necessary to bear the pressure of a considerable weight of water, as well as the violence of the waves, when the animal came to the surface to breathe, and raised its head above the waves. This magnificent specimen of the fish-lizard, or Ichthyosaurus, as it was named by Dr. Ure, now forms part of the treasures of the British Museum. At no period in the earth’s history have Reptiles occupied so important a place as they did in the Jurassic period. Nature seems to have wished to bring this class of animals to the highest state of development. The great Reptiles of the Lias are as complicated in their structure as the Mammals which appeared at a later period. They probably lived, for the most part, by fishing in shallow creeks and bays defended from heavy breakers, or in the open sea; but they seem to have sought the shore from time to time; they crawled along the beach, covered with a soft skin, perhaps not unlike some of our CetaceÆ. The Ichthyosaurus, from its form and strength, may have braved the waves of the sea as the porpoise does now. Its destructiveness and voracity must have been prodigious, for Dr. Buckland describes a specimen which had between its ribs, in the place where the stomach might be supposed to have been placed, the skeleton of a smaller one—a proof that this monster, not content with preying on its weaker neighbours, was in the habit of devouring its own kind. In the same waters lived the Plesiosaurus, with long neck and form more strange than that of the Ichthyosaurus; and these potentates of The great Saurians in the Lias of Lyme Regis seem to have suffered a somewhat sudden death, partly in consequence of a series of small catastrophes suddenly destroying the animals then existing in particular spots. “In general the bones are not scattered about, and in a detached state, as would happen if the dead animal had descended to the bottom of the sea, to be decomposed, or devoured piecemeal, as, indeed, might also happen if the creature floated for a time on the surface, one animal devouring one part, and another carrying off a different portion; on the contrary, the bones of the skeleton, though frequently compressed, as must arise from the enormous pressure to which they have so long been subjected, are tolerably connected, frequently in perfect, or nearly perfect, order, as if prepared by the anatomist. The skin, moreover, may sometimes be traced, and the compressed contents of the intestines may at times be also observed—all tending to show that the animals were suddenly destroyed, and as suddenly preserved.” These strange and gigantic Saurians seem almost to disappear during the succeeding geological periods; for, although they have been discovered as low down as the Trias in Germany, and as high up as the Chalk in England, they only appear as stragglers in these epochs; so, too, the Reptiles, the existing Saurians are, as it were, only the shadowy, feeble representatives of these powerful races of the ancient world. Confining ourselves to well-established facts, we shall consider in some detail the best known of these fossil reptiles—the Ichthyosaurus, Plesiosaurus, and Pterodactyle. The extraordinary creature which bears the name of Ichthyosaurus (from the Greek words ????? sa????, signifying fish-lizard), presents certain dispositions and organic arrangements which are met with dispersed in certain classes of animals now living, but they never seem to be again reunited in any single individual. It possesses, as Cuvier says, the snout of a dolphin, the head of a lizard, the jaws and teeth of a crocodile, the vertebrÆ of a fish, the head and sternum of a lizard, the paddles like those of a whale, and the trunk and tail of a quadruped. Bayle appears to have furnished the best idea of the Ichthyosaurus by describing it as the Whale of the Saurians—the Cetacean of the Fig. 96.—Ichthyosaurus platydon. The dimensions of the Ichthyosaurus varied with the species, of which five are known and described. These are Ichthyosaurus communis, I. platydon, I. intermedius, I. tenuirostris, and I. Cuvierii, the largest being more than thirty feet in length. Fig. 97.—Lower jaw of Ichthyosaurus. (Dr. Buckland.) The short, thick neck of the Ichthyosaurus supported a capacious head, and was continued backwards, from behind the eyes, in a column composed of more than a hundred vertebrÆ. The animal being adapted, like the whale, for rapid movement through the water, its vertebrÆ had none of the invariable solidity of those of the Lizard or Crocodile, In order that the animal should be able to move with rapidity in the water, both its anterior and posterior members were converted into fins or paddles. The anterior fins were half as large again as the posterior. In some species each paddle was made up of nearly a hundred bones, of polygonal form, and disposed in series representing the phalanges of the fingers. This hand, jointed at the arm, bears resemblance, in osteological construction, to the paddles, without distinct fingers, of the Porpoise and the Whale. A specimen of the posterior fin of I. communis, discovered at Barrow-on-Soar, in Leicestershire, in 1840, by Sir Philip Egerton, exhibited on its posterior margin the remains of cartilaginous rays, which bifurcated as they approached the edge, like those in the fins of a fish. “It had previously been supposed,” says Professor Owen, “that the locomotive organs were enveloped, while living, in a smooth integument, like that of the turtle and porpoise, which has no other support than is afforded by the bones and ligaments within; but it now appears that the fin was much larger, expanding far beyond the osseous frame-work, and deviating widely in its fish-like rays from the ordinary reptilian type.” The Professor believes that, besides the fore-paddles, these stiff-necked Saurians were furnished at the end of the tail with a fin to assist them in turning, not placed horizontally, as in the whale, but vertically, forming a powerful instrument of progression and motion. It is obvious that the Ichthyosaurus was an animal powerfully armed for offence and defence. We cannot say, with certainty, whether the skin was smooth, like that of the whale or lizard, or covered with scales, like the great reptiles of our own age. Nevertheless, as the scales of the Fishes and the cuirass and horny armour of other Reptiles of the Lias are preserved, and as no such defensive scales have been found belonging to the Ichthyosaurus, it is probable that the skin was naked and smooth. The tail, composed of from eighty to eighty-five vertebrÆ, was provided with large and long paddles, arranged vertically as in the Whale. Fig. 98.—Skeleton of Ichthyosaurus. It is curious to see to what a degree of perfection has been carried, in our days, the knowledge of the antediluvian animals, their habits, and their economy. Fig. 98 represents the skeleton of an Ichthyosaurus found in the Lias of Lyme Regis, which still retains in its abdominal cavity coprolites, that is to say, the residue of digestion. The soft parts of the intestinal canal have disappeared, but the fÆces themselves are preserved, and their examination informs us as to the Fig. 99.—Coprolite, enclosing bones of small Ichthyosaurus. The perfection with which its contents have been preserved in the fossilised coprolites, furnishes indirect proofs that the intestinal canal of the Ichthyosaurus resembled closely that of the shark and the dog-fish—fishes essentially voracious and destructive, which have the intestinal canal spirally convoluted, an arrangement which is exactly that indicated in some of the coprolites Fig. 100.—Coprolite of Ichthyosaurus. What an admirable privilege of science, which is able, by an examination of the simplest parts in the organisation of beings which lived ages ago, to give to our minds such solid teachings and such true enjoyments! “When we discover,” says Dr. Buckland, “in the body of an Ichthyosaurus the food which it has engulfed an instant before its death, when the intervals between its sides present themselves still filled with the remains of fishes which it had swallowed some ten thousand years ago, or a time even twice as great, all these immense intervals vanish, time disappears, and we find ourselves, so to speak, thrown into immediate contact with events which took place in epochs immeasurably distant, as if we occupied ourselves with the affairs of the previous day.” Fig. 101.—Skull of Plesiosaurus restored. (Conybeare.) The name of Plesiosaurus (from the Greek words p??s???, near, and sa????, lizard) reminds us that this animal, though presenting many peculiarities of general structure, is allied by its organisation to the Saurian or Lizard family, and, consequently, to the Ichthyosaurus. The Plesiosaurus presents, in its organic structure, the most curious The head of the Plesiosaurus presents a combination of the characters belonging to the Ichthyosaurus, the Crocodile, and the Lizard. Its enormously long neck comprises a greater number of vertebrÆ than the neck of either the Camel, the Giraffe, or even the Swan, which of all the feathered race has the longest neck in comparison to the rest of the body. And it is to be remarked, that, contrary to what obtains in the Mammals, where the vertebrÆ of the neck are always seven, the vertebrÆ in birds increase in number with the length of the neck. Fig. 102.—Skeleton of Plesiosaurus dolichodeirus restored. (Conybeare principally.) The body is cylindrical and rounded, like that of the great marine Turtles. It was, doubtless, naked, i.e., not protected with the scales or carapace with which some authors have invested it; for no traces of such coverings have been found near any of the skeletons which have been hitherto discovered. The dorsal vertebrÆ are attached to each other by nearly plane surfaces like those of terrestrial quadrupeds, a mode of arrangement which must have deprived the whole of its vertebral Fig. 103.—Sternum and pelvis of Plesiosaurus. Pub., pubis; Isch., ischium; Il., ilium. The breast, the pelvis, and the bones of the anterior and posterior extremities furnished an apparatus which permitted the Plesiosaurus, like the Ichthyosaurus and existing Cetaceans, to sink in the water and return to the surface at pleasure (Fig. 103). Prof. Owen, in his “Report on British Reptiles,” characterises them as air-breathing and cold-blooded animals; the proof that they respired atmospheric air immediately, being found in the position and structure of the nasal passages, and the bony mechanism of the thoracic duct and abdominal cavity. In the first, the size and position of the external nostrils (Fig. 102), combined with the structure of the paddles, indicate a striking analogy between the extinct Saurians and the Cetaceans, offering, as the Professor observes, “a beautiful example of the adaptation of structure to the peculiar exigencies of species.” While the evidence that they were cold-blooded animals is found in the flexible or unanchylosed condition of the osseous pieces of the occiput and other cranial bones of the lower jaw, and of the vertebral column; from which the Professor draws the conclusion that the heart was adapted for transmitting a part only of the blood through the respiratory organs; the absence of the ball-and-socket articulations of the bones of the vertebrÆ, the position of the nostrils near the summit of the head, the numerous short and flat digital bones, which must have been enveloped in a simple undivided integumentary sheath, forming in both fore and hind extremities a paddle closely resembling that of the living Cetacea. The paddles are larger and more powerful than those of the Ichthyosaurus, to compensate for the slight assistance the animal derived from the tail. The latter—shorter, as compared with the length of the rest of the body, than in the Ichthyosaurus—was more calculated to act the part of a rudder, Such were the strange combinations of form and structure in the Plesiosaurus and Ichthyosaurus—genera of animals whose remains have, after an interment extending to unknown thousands of years, been revealed to light and submitted to examination; nay, rebuilt, bone by bone, until we have the complete skeletons before us, and the habits of the animals described, as if they had been observed in life. Conybeare thus speaks of the supposed habits of these extinct forms, which he had built up from scanty materials: “That the Plesiosaurus was aquatic is evident from the form of its paddles; that it Fig. 104.—Remains of Plesiosaurus macrocephalus. One-twelfth natural size. The Plesiosaurus was first described by the Rev. W. D. Conybeare and Sir Henry De la Beche, in the “Geological Society’s Transactions” for 1821, and a restoration of P. dolichodeirus, the most common of these fossils, appeared in the same work for 1824. The first specimen was discovered, as the Ichthyosaurus had been previously, in the Lias of Lyme Regis; since then other individuals and species have been found in the same geological formation in various parts of England, Ireland, France, and Germany, and with such variations of structure that Professor Owen has felt himself justified in recording sixteen distinct species, of which we have represented P. dolichodeirus (Fig. 102), as restored by Conybeare, and P. macrocephalus (Fig. 104), with its skeleton, as moulded from the limestone of Lyme Regis, which has been placed in the PalÆontological Gallery of the British Museum. XV.—Ideal scene of the Lias with Ichthyosaurus and Plesiosaurus. The Plesiosaurus was scarcely so large as the Ichthyosaurus. The specimen of I. platydon in the British Museum probably belonged to an animal four-and-twenty feet long, and some are said to indicate thirty feet, while there are species of Plesiosauri measuring eighteen and twenty, the largest known specimen of Plesiosaurus Cramptoni found in the lias of Yorkshire, and now in the Museum of the Royal Society of Dublin, being twenty-two feet four inches in length. On the opposite page (Plate XV.) an attempt is made to represent these grand reptiles of the Lias in their native element, and as they lived. Another strange inhabitant of the ancient world, the Pterodactylus (from pte???, a wing, and da?t????, a finger), discovered in 1828, made Cuvier pronounce it to be incontestably the most extraordinary of all the extinct animals which had come under his consideration; and such as, if we saw them restored to life, would appear most strange and dissimilar to anything that now exists. In size and general form, and in the disposition and character of its wings, this fossil genus, according to Cuvier, somewhat resembled our modern bats and vampyres, but had its beak elongated like the bill of a woodcock, and armed with teeth like the snout of a crocodile; its vertebrÆ, ribs, pelvis, legs, and feet resembled those of a lizard; its three anterior fingers terminated in long hooked claws like that on the fore-finger of the bat; and over its body was a covering, neither composed of feathers as in the bird, nor of hair as in the bat, but probably a naked skin; in short, it was a monster resembling nothing that has ever been heard of upon earth, except the dragons of romance and heraldry. Moreover, Fig. 105.—Pterodactylus crassirostris. “The Fiend, O’er bog, or steep, through strait, rough, dense, or rare, With head, hands, wings, or feet, pursues his way, And sinks, or swims, or wades, or creeps, or flies. Paradise Lost, Book II., line 947. “With flocks of such-like creatures flying in the air, and shoals of Ichthyosauri and Plesiosauri swarming in the ocean, and gigantic Crocodiles and Tortoises crawling on the shores of primÆval lakes and rivers—air, sea, and land must have been strangely tenanted in these early periods of our infant world.” The strange structure of this animal gave rise to most contradictory opinions from the earlier naturalists. One supposed it to be a bird, another a bat, and others a flying reptile. Cuvier was the first to detect the truth, and to prove, from its organisation, that the animal was a Saurian. “Behold,” he says, “an animal which in its osteology, from its teeth to the end of its claws, presents all the characters of the Saurians; nor can we doubt that their characteristics existed in its integuments and softer parts, in its scales, its circulation, its generative organs: it was at the same time provided with the means of flight; but when stationary it could not have made much use of its anterior extremities, even if it did not keep them always folded Fig. 106.—Pterodactylus brevirostris. 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, it perched 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, so 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 played 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 DraconidÆ, 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 Fig. 107.—Draco volans. 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 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 Nilssonia. Among the species which characterise this age, we may cite the following, arranging them in families:—
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 Pterophyllum (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 summit and traversed by fine nervures, not convergent, but abutting on the terminal truncated edge. The Nilssonia, finally, were CycadeaceÆ resembling the Pterophyllum, Fig. 108.—Millepora alcicornis. The essential characters of the vegetation during the Liassic sub-period were:—1. The great predominance of the CycadeaceÆ, thus continuing the development which commenced in the previous period, expanding into numerous genera belonging both to this family and that of the Zamites and Nilssonia; 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. XVI.—Ideal Landscape of the Liassic Period. 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 allied to those of our own age. Among animals, we see the Pterodactyle specially represented. One of these reptiles 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 ???, egg, and ?????, stone. 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:—
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; it forms what is called a tame landscape, as compared with the wilder grandeur of the Primary rocks—it pleases more than it surprises. It yields materials also, more useful than some of the older formations, numerous quarries being met with which furnish excellent building-materials, especially around Bath, where the stone, when 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. Fig. 109.—General view of the succession of British strata, with the elevations they reach above the level of the sea. Lower Oolite Fauna.The most salient and characteristic feature of this age is, undoubtedly, the appearance of animals belonging to the class of Mammals. But the organisation, quite special, of the first of the Mammalia will certainly be a matter of astonishment to the reader, and must satisfy him that Nature proceeded in the creation of animals by successive steps, by transitions which, in an almost imperceptible manner, connect the beings of one age with others more complicated in their organisation. The first Mammals which appeared upon the earth, for example, did not enjoy all the organic attributes belonging to the more recent creations of the class. In the latter the young are brought forth living, and not from eggs, like Birds, Reptiles, and Fishes. But the former belonged to that order of animals quite special, and never numerous, the young of which are transferred in a half-developed state, from the body of the mother to an external pouch in which they remain until they become perfected; in short, to marsupial animals. The mother nurses her young during a certain time in a sort of pouch external to the body, in the neighbourhood of the abdomen, and provided with teats to which the young adhere. After a more or less prolonged sojourn in this pouch, the young animal, when sufficiently In standard works on natural history the animals under consideration are classed as mammiferous DidelphÆ. They are brought forth in an imperfect state, and during their transitional condition are suckled in a pouch supported by bones called marsupial, which are attached by their extremities to the pelvis, and serve to support the marsupium, whence the animals provided with these provisions for bringing up their progeny are called Marsupial Mammals. The Opossum, Kangaroo, and Ornithorhynchus are existing representatives of this group. Fig. 110.—Jaw of Thylacotherium Prevostii. Fig. 111.—Jaw of Phascolotherium. The name of Thylacotherium, or Amphitherium, or Phascolotherium, is given to the first of these marsupial Mammals which made their appearance, whose remains have been discovered in the Lower Oolite, and in one of its higher stages, namely, that called the Great Oolite. Fig. 110 represents the jaw of the first of these animals, and Fig. 111 the other—both of the natural size. These jaw-bones represent all that has been found belonging to these early marsupial animals; and Baron Cuvier and Professor Owen have both decided as to their origin. The first was found in the Stonesfield quarries. The Phascolotherium, also a Stonesfield fossil, was the ornament of Mr. Broderip’s collection. The animals which lived on the land during the Lower Oolitic period would be nearly the same with those of the Liassic. The insects were, perhaps, more numerous. Fig. 112.—Ammonites Herveyii. Fig. 113.—Terebratula digona. The marine fauna included Reptiles, Fishes, Molluscs, and Zoophytes. Among the first were the Pterodactyle, and a great Saurian, the Teleosaurus, belonging to a family which made its appearance in this age, and which reappears in the following epoch. Fig. 114.—Pleurotoma Babylonia. (Recent.) Fig. 115.—Adeona folifera. Fig. 116.—Cellaria loriculata. This last and most remarkable species of Zoophyte presents itself in great masses many yards in circumference, and necessitates a long period of time for its production. This assemblage of little creatures living under the waters but only at a small depth beneath the surface, as Mr. Darwin has demonstrated, has nevertheless produced banks, or rather islets, of considerable extent, which at one time constituted veritable reefs rising out of the ocean. These reefs were principally constructed in the Jurassic period, and their extreme abundance is one of the characteristics of this geological age. The same phenomenon continues in our day, but by the agency of a new race of Fig. 117. The flora of the epoch was very rich. The Ferns continue to exist, but their size and bearing were sensibly inferior to what they had been in the preceding period. Among them Otopteris, distinguished The vegetation of this epoch has a peculiar facies, from the presence of the family of the PandanaceÆ, or screw-pines, so remarkable for their aËrial roots, and for the magnificent tuft of leaves which terminates their branches. Neither the leaves nor the roots of these plants have, however, been found in the fossil state, but we possess specimens of their large and spherical fruit, which leave no room for doubt as to the nature of the entire plant. The Cycads were still represented by the Zamias, and by many species of Pterophyllum. The Conifers, that grand family of recent times, to which the pines, firs, and other trees of our northern forests belong, began to occupy an important part in the world’s vegetation from this epoch. The earliest Conifers belonged to the genera Thuites, Taxites, and Brachyphyllum. The Thuites were true Thuyas, evergreen trees of the present epoch, with compressed branches, small imbricated and serrated leaves, somewhat resembling those of the Cypress, but distinguished by many points of special organisation. The Taxites have been referred, with some doubts, to the Yews. Finally, the Brachyphyllum were trees which, according to the characteristics of their vegetation, seem to have approached nearly to two existing genera, the Arthotaxis of Tasmania, and the Weddringtonias of South Africa. The leaves of the Brachyphyllum are short and fleshy, with a large and rhomboidal base. Lower Oolite Rocks.The formation which represents the Lower Oolite, and which in England attains an average thickness of from 500 to 600 feet, forms a very complex system of stratification, which includes the two formations, Bajocien and Bathonian, adopted by M. D’Orbigny and his followers. The lowest beds of the Inferior Oolite occur in Normandy, in the Lower Alps (Basses-Alpes), in the neighbourhoods of Lyons and Neuchatel. They are remarkable near Bayeux for the variety and beauty of their fossils: the rocks are composed principally of limestones—yellowish-brown, or red, charged with hydrated oxide of iron, often oolitic, and reposing on calcareous sands. These 1. The Great or Bath Oolite, which consists principally of a very characteristic, fine-grained, white, soft, and well-developed oolitic limestone, at Bath, and also at Caen in Normandy. At the base of the Great Oolite the Stonesfield beds occur, in which were found the bones of the marsupial Mammals, to which we have already alluded; and along with them bones of Reptiles, principally Pterodactyles, together with some finely-preserved fossil plants, fruits, and insects. 2. Bradford Clay, which is a bluish marl, containing many fine Encrinites (commonly called stone-lilies), but which had only a local existence, appearing to be almost entirely confined to this formation. “In this case, however,” says Lyell, “it appears that the solid upper surface of the ‘Great Oolite’ had supported, for a time, a thick submarine forest of these beautiful Zoophytes, until the clear and still water was invaded with a current charged with mud, which threw down the stone-lilies, and broke most of their stems short off near the point of attachment. The stumps still remain in their original position.” 3. Forest Marble, which consists of an argillaceous shelly limestone, abounding in marine fossils, and sandy and quartzose marls, is quarried in the forest of Wichwood, in Wiltshire, and in the counties of Dorset, Wilts, and Somerset. 4. The Cornbrash (wheat-lands) consists of beds of rubbly cream-coloured limestone, which forms a soil particularly favourable to the cultivation of cereals; hence its name. The Lower Oolite ranges across the greater part of England, but “attains its maximum development near Cheltenham, where it can be subdivided, at least, into three parts. Passing north, the two lower divisions, each more or less characterised by its own fossils, disappear, and the Ragstone north-east of Cheltenham lies directly Fig. 118.—Meandrina DÆdalÆa. The Inferior Oolite here alluded to is a thin bed of calcareous freestone, resting on, and sometimes replaced by yellow sand, which constitutes the passage-beds from the Liassic series. The Fullers’ Earth clay lies between the limestones of the Inferior and Great Oolite, at the base of which last lies the Stonesfield slate—a slightly oolitic, shelly limestone, or flaggy and fissile sandstone, some six feet thick, rich in organic remains, and ranging through Oxfordshire towards the north-east, into Northamptonshire and Yorkshire. At Colley Weston, in Northamptonshire, fossils of Pecopteris polypodioides are found. In the Great Oolite formation, near Bath, are many corals, among which the Eunomia radiata is very conspicuous. The fossil is not unlike the existing brain-coral of the tropical seas (Fig. 118). The work of this coral seems to have been suddenly stopped by “an invasion,” says Lyell, “of argillaceous matter, which probably put a sudden stop to the growth of Bradford Encrinites, and led to their preservation in marine strata.” XVII.—Ideal Landscape of the Lower Oolite Period. On the opposite page (Plate XVII.) is represented an ideal landscape of the period of the Lower Oolite. On the shore are types of the vegetation of the period. The Zamites, with large trunk covered with fan-like leaves, resembled in form and bearing the existing Zamias of tropical regions; a Pterophyllum, with its stem covered from base to summit with its finely-cut feathery leaves; Conifers closely resembling our Cypress, and an arborescent Fern. What distinguishes this sub-period from that of the Lias is a group of magnificent trees, Pandanus, remarkable for their aËrial roots, their long leaves, and globular fruit. Upon one of the trees of this group the artist has placed the Phascolotherium, not very unlike to our Opossum. It was amongst the first of the Mammalia which appeared in the ancient world. The artist has here enlarged the dimensions of the animal in order to show its form. Let the reader reduce it in imagination one-sixth, for it was not larger than an ordinary-sized cat. A Crocodile and the fleshless skeleton of the Ichthyosaurus remind us that Reptiles still occupied an important place in the animal creation. A few Insects, especially Dragon-flies, fly about in the air. Ammonites float on the surface of the waves, and the terrible Plesiosaurus, like a gigantic swan, swims about in the sea. The circular reef of coral, the work of ancient Polyps, foreshadows the atolls of the great ocean, for it was during the Jurassic period that the Polyps of the ancient world were most active in the production of coral-reefs and islets. Middle Oolite.The terrestrial flora of this age was composed of Ferns, Cycads, and Conifers. The first represented by the Pachypteris microphylla, the second by Zamites Moreana. Brachyphyllum Moreanum and B. majus appear to have been the Conifers most characteristic of the period; fruits have also been found in the rocks of the period, which appear to belong to Palms, but this point is still obscure and doubtful. Numerous vestiges of the fauna which animated the period are also revealed in the rocks of this age. Certain hemipterous insects appear on the earth for the first time, and the Bees among the Hymenoptera, Butterflies among the Lepidoptera, and Dragon-flies The Ceteosaurus whose bones have been discovered in the upper beds of the Great Oolite at Enslow Rocks, at the Kirtlington Railway Station, north of Oxford, and some other places, was a species of Crocodile nearly resembling the modern Gavial or Crocodile of the Ganges. This huge whale-like reptile has been described by Professor John Phillips as unmatched in size and strength by any of the largest inhabitants of the Mesozoic land or sea—perhaps the largest animal that ever walked upon the earth. A full-grown Ceteosaurus must have been at least fifty feet long, ten feet high, and of a proportionate bulk. In its habits it was, probably, a marsh-loving or river-side animal, dwelling amidst filicene, cycadaceous, and coniferous shrubs and trees full of insects and small mammalia. The one small and imperfect tooth which has been found resembles that of Iguanodon more than of any other reptile; and it seems probable that the Ceteosaurus was nourished by vegetable food, which abounded in the vicinity of its haunts, and was not obliged to contend with the Megalosaurus for a scanty supply of more stimulating diet. Fig. 119.—Ramphorynchus restored. One-quarter natural size. Another reptile allied to the Pterodactyle lived in this epoch—the Ramphorynchus, distinguished from the Pterodactyle by a long tail. The imprints which this curious animal has left upon the sandstone of the period are impressions of its feet and the linear furrow made by its tail. Like the Pterodactyle, the Ramphorynchus, which was about the size of a crow, could not precisely fly, but, aided by the wing (a sort of natural parachute formed by the membrane connecting the fingers with the body), it could throw itself from a height upon its prey. Fig. 119 represents a restoration of this animal. The footprints in the soil are in imitation of those which accompany the remains of the Ramphorynchus in the Oolitic rocks, and they show the imprints of the anterior and posterior feet and also the marks made by the tail. This tail was very long, far surpassing in length the rest of the vertebral column, and consisting of more than thirty vertebrÆ—which were at first short, but rapidly elongate, retain their length for a considerable distance, and then gradually diminish in size. XVIII.—Ideal landscape of the Middle Oolitic Period. Another genus of Reptiles appears in the Middle Oolite, of which we have had a glimpse in the Lias and Great Oolite of the preceding section. This is the Teleosaurus, which the recent investigations of The Teleosaurus resembled the Gavials of India. The former inhabited the banks of rivers, perhaps the sea itself; they were longer, more slender, and more active than the living species; they were about thirty feet in length, of which the head may be from three to four feet, with their enormous jaws sometimes with an opening of six feet, through which they could engulf, in the depths of their enormous throat, animals of considerable size. The Teleosaurus cadomensis is represented on the opposite page (Plate XVIII.), after the sketch of M. E. Deslongchamps, carrying from the sea in its mouth a Geoteuthis, a species of Calamary of the Oolitic epoch. This creature was coated with a cuirass both on the back and belly. In order to show this peculiarity, a living individual is represented on the shore, and a dead one is floating on its back in shallow water, leaving the ventral cuirass exposed. Behind the Teleosaurus cadomensis in the engraving, another Saurian, the HylÆosaurus, is represented, which makes its appearance Fig. 120.—Eryon arctiformis. Besides the numerous Fishes with which the Oolitic seas swarmed, they contained some Crustaceans, Cirripedes, and various genera of Mollusca and Zoophytes. Eryon arctiformis, represented in Fig. 119, belongs to the class of Crustaceans, of which the spiny lobster is the type. Among the Mollusca were some Ammonites, Belemnites, and Oysters, of which many hundred species have been described. Of these we may mention Ammonites refractus, A. Jason and A. cordatus, Ostrea dilatata, Terebratula diphya, Diceras arietena, Belemnites hastatus, and B. Puzosianus. In some of the finely-laminated clays the Ammonites are very perfect, but somewhat compressed, with the outer lip or margin of the aperture entire (Fig. 120). Similar prolongations have been noticed in Belemnites found by Dr. Mantell in the Oxford Clay, near Chippenham. Fig. 121.—Perfect Ammonite. XIX.—Fig. 1.—Apiocrinites rotundus. Fig. 2.—Encrinus liliiformis. Among the Echinoderms, Cidaris glandiferus, Apiocrinus Roissyanus, and A. rotundus, the graceful Saccocoma pectinata, Millericrinus nodotianus, Comatula costata, and Hemicidaris crenularis may be mentioned; Apiocrinites rotundus, figured in Plate XIX., is a reduced restoration: 1, being expanded; a, closed; 3, a cross section of the The Corals of this epoch occur in great abundance. We have already remarked that these aggregations of Polyps are often met with at a great depth in the strata. These small calcareous structures have been formed in the ancient seas, and the same phenomenon is extending the terrestrial surface in our days in the seas of Oceania, where reefs and atolls of coral are rising by slow and imperceptible steps, but with no less certainty. Although their mode of production must always remain to some extent a mystery, the investigations of M. Lamaroux, Mr. Charles Darwin, and M. D’Orbigny have gone a long way towards explaining their operations; for the Zoophyte in action is an aggregation of these minute Polyps. Describing what he believes to be a sea-pen, a Zoophyte allied to Virgularia Patagonia, Mr. Darwin says: “It consists of a thin, straight, fleshy stem, with alternate rows of polypi on each side, and surrounding an elastic stony axis. The stem at one extremity is truncate, but at the other is terminated by a vermiform fleshy appendage. The stony axis which gives strength to the stem, may be traced at this extremity into a mere vessel filled with granular matter. At low water hundreds of these zoophytes might be seen, projecting like stubble, with the truncate end upwards, a few inches above the surface of the muddy sand. When touched or pulled, they drew themselves in suddenly, with force, so as nearly or quite to disappear. By this action, the highly-elastic axis must be bent at the lower extremity, where it is naturally slightly curved; and I imagine it is by this elasticity alone that the zoophyte is enabled to rise again through the mud. Each polypus, though closely united to its brethren, has a distinct mouth, body, and tentacula. Of these polypi, in a large specimen there must be many thousands. Yet we see that they act by one movement; that they have one central axis, connected with a system of obscure circulation.” Such is the brief account given by a very acute observer of these singular beings. They secrete the calcareous matter held in solution in the oceanic waters, and produce the wonderful structures we have now under consideration; and these calcareous banks have been in course of formation during many geological ages. They The rocks which now represent the Middle Oolitic Period are usually divided into the Oxford Clay, the lower member of which is an arenaceous limestone, known as the Kellaways Rock, which in Wiltshire and other parts of the south-west of England attains a thickness of eight or ten feet, with the impressions of numerous Ammonites, and other shells. In Yorkshire, around Scarborough, it reaches the thickness of thirty feet; and forms well-developed beds of bluish-black marl in the department of Calvados, in France. It is the base of this clay which forms the soil (Argile de Dives) of the valley of the Auge, renowned for its rich pasturages and magnificent cattle. The same beds form the base of the oddly-shaped but fine rocks of La Manche, which are popularly known as the Vaches Noires (or black cows)—a locality celebrated, also, for its fine Ammonites transformed into pyrites. The Oxford Clay constitutes the base of the hills in the neighbourhood of Oxford, forming a bed of clay sometimes more than 600 feet thick. It is found well-developed in France, at Trouville, in the department of the Calvados; and at Neuvisy, in the department of the Ardennes, where it attains a thickness of about 300 feet. It is a bluish, sometimes whitish limestone (often argillaceous), and bluish marl. The GryphÆa dilatata is the most common fossil in the Oxford Clay. The Coral Rag is so called from the fact that the limestone of which it is chiefly composed consists, in part, of an aggregation of considerable masses of petrified Corals; not unlike those now existing in the Pacific Ocean, supposing them to be covered up for ages and fossilised. This coral stratum extends through the hills of Berkshire and North Wilts, and it occurs again near Scarborough. In the counties of Dorset, Bedford, Buckingham, and Cambridge, and some other parts of England, the limestone of the Coral Rag disappears and is replaced by clay—in which case the Oxford Clay is overlaid directly by the Kimeridge Clay. In France it is found in the departments of the Meuse, of the Yonne, of the Ain, of the Charente InfÉrieure. In the Alps the Diceras limestone is regarded, by most geologists, as coeval with the English Coral Rag. Upper Oolite.Some marsupial Mammals have left their remains in the Upper Oolite as in the Lower. They belong to the genus Sphalacotherium. Besides the Plesiosauri and Teleosauri, there still lived in the maritime regions a Crocodile, the Macrorhynchus; and the monstrous Poecilopleuron, with sharp cutting teeth, one of the most formidable animals of this epoch; the HylÆosaurus, Cetiosaurus, Stenosaurus, and Streptospondylus, and among the Turtles, the Emys and Platemys. Fig. 122.—Bird of Solenhofen (ArchÆopteryx). The most remarkable fact relating to this period is the appearance of the first bird. Hitherto the Mammals, and of these only imperfectly-organised species, namely, the Marsupials, have alone appeared. It is interesting to witness birds appearing immediately after. In the quarries of lithographic stone at Solenhofen, the remains of a bird, with feet and feathers, have been found, but without the head. These curious remains are represented in Fig. 122, in the position in which they were discovered. The bird is usually designated the Bird of Solenhofen. Fig. 123. The Oolitic seas of this series contained Fishes belonging to the genera Asteracanthus, Strephodes, Lepidotus, and Microdon. The Cephalopodous Mollusca were not numerous, the predominating genera belonging to the Lamellibranchs and to the Gasteropods, which lived on the shore. The reef-making Madrepores or Corals were more numerous. A few Zoophytes in the fossil state testify to the existence of these extraordinary animals. The fossils characteristic of the fauna of the period include Ammonites decipiens and A. giganteus, Natica elegans and hemispherica, Ostrea deltoidea and O. virgula, Trigonia gibbosa, Pholadomya multicostata and P. acuticostata, Terebratula subsella, and Hemicidaris Purbeckensis. Some Fishes, Turtles, Paludina, Physa (Fig. 123), Unio, Planorbis (Fig. 201), and the little crustacean bivalves, the Cypris, constituted the fresh-water fauna of the period. The terrestrial flora of the period consisted of Ferns, CycadeaceÆ, and Conifers; in the ponds and swamps some ZosterÆ. The ZosterÆ are monocotyledonous plants of the family of the NaÏdaceÆ, which grow in the sandy mud of maritime regions, forming there, with their long, narrow, and ribbon-like leaves, vast prairies of the most beautiful green. At low tides these masses of verdure appear somewhat exposed. They would form a retreat for a great number of marine animals, and afford nourishment to others. XX.—Ideal Landscape of the Upper Oolitic Period. On the opposite page an ideal landscape of the period (Plate XX.) represents some of the features of the Upper Oolite, especially the The rocks which represent the Upper Oolite are usually divided into two series: 1. The Purbeck Beds; 2. The Portland Stone and Sand; and 3. The Kimeridge Clay. The Kimeridge Clay, which in many respects bears a remarkable resemblance to the Oxford Clay, is composed of blue or yellowish argillaceous beds, which occur in the state of clay and shale (containing locally beds of bituminous schist, sometimes forming a sort of earthy impure coal), and several hundred feet in thickness. These beds are well developed at Kimeridge, in Dorsetshire, whence the clay takes its name. In some parts of Wiltshire the beds of bituminous matter have a shaly appearance, but there is an absence of the impressions of plants which usually accompany the bitumen, derived from the decomposition of plants. These rocks, with their characteristic fossils, Cardium striatulum and Ostrea deltoidea, are found throughout England: in France, at Tonnerre, Dept. Yonne; at Havre; at Honfleur; at Mauvage; in the department of the Meuse it is so rich in shells of Ostrea deltoidea and O. virgula, that, “near Clermont in Argonne, a few leagues from St. Menehould,” says Lyell, The second section of this series consists of the oolitic limestone of Portland, which is quarried in the Isle of Portland and in the cliffs of the Isle of Purbeck in Dorsetshire, and also at Chilmark in the Vale of Wardour, in Wiltshire. In France, the Portland beds are found near Boulogne, at Cirey-le-ChÂteau, Auxerre, and Gray (Haute SaÔne). Time passed on, however; a calcareous sediment brought from the interior by the waters, formed a layer of mud over the dirt-bed; finally, the whole region was covered by a succession of calcareous deposits, until the day when the Isle of Portland was again revealed to light. “From the facts observed,” says Lyell, “we may infer:—1. Fig. 124.—Geological humus. a, Fresh-water calcareous slate (Purbeck); b, Dirt-bed, with roots and stems of trees; c, Fresh-water beds; d, Portland Stone. The soil known as the dirt-bed is nearly horizontal in the Isle of Portland; but we discover it again not far from there in the sea-cliffs of the Isle of Purbeck, having an inclination of 45°, where the trunks continue perfectly parallel among themselves, affording a fine example of a change in the position of beds originally horizontal. Fig. 124 represents this species of geological humus. “Each dirt-bed” says Sir Charles Lyell, “may, no doubt, be the memorial of many thousand years or centuries, because we find that two or three feet of vegetable soil is the only monument which many a tropical forest has left of its existence ever since the ground on which it now stands was first covered with its shade.” This bed of vegetable soil is, then, near the summit of that long and complicated series of beds which constitute the Jurassic period; these ruins, still vegetable, remind us forcibly of the coal-beds, for they are nothing else than a less advanced state of that kind of vegetable fossilisation which was perfected on such an immense scale, and during an infinite length of time in the coal period. The Middle series consists of twelve feet of marine strata known as the “cinder-beds,” formed of a vast accumulation of Ostrea distorta, resting on fresh-water strata full of Cypris fasciculata, Planorbis, and LimnÆa, by which this strata has been identified as far inland as the vale of Wardour in Wiltshire. Above the cinder-beds are shales and limestones, partly of fresh-water and partly of brackish-water origin, in which are Fishes, many species of Lepidotus, and the crocodilian reptile, Macrorhynchus. On this rests a purely marine deposit, with Pecten, Avicula, &c. Above, again, are brackish beds with Cyrena, overlying which is thirty feet of fresh-water limestone, with Fishes, Turtles, and Cyprides. The upper beds are purely fresh-water strata, about fifty feet thick, containing Paludina, Physa, LimnÆa, all very abundant. In these beds the Purbeck marble, formerly much used in the ornamental architecture of the old English cathedrals, was formerly quarried. (See Note, page 274.) A few words may be added, in explanation of the term oolite, applied to this sub-period of the Jurassic formation. In a great number of rocks of this series the elements are neither crystalline nor amorphous—they are, as we have already said, oolitic; that is to say, the mass has the form of the roe of certain fishes. The question naturally enough arises, Whence this singular oolitic structure assumed by the components of certain rocks? It is asserted that the grinding action of the sea acting upon the precipitated limestone produces rounded forms analogous to grains of sand. This hypothesis may be well founded in some cases. The marine sediments which are deposited in some of the warm bays of Teneriffe are found to take the spheroidal granulated form of the oolite. But these local facts cannot be made to apply to the whole extent of the oolitic formations. We must, therefore, look further for an explanation of the phenomena. On the other hand, it is known that nodules, more or less large, develop themselves in marls in consequence of the concentration of the calcareous elements, without the possibility of any wearing action of water. Now, as there exists every gradation of size between the smallest oolitic grains and the largest concretions, it is reasonable to suppose that the oolites are equally the product of concentration. Finally, from research to research, it is found that perfectly constituted oolites—that is to say, concentric layers, as in the Jurassic limestone—develop themselves in vegetable earth in places where the effects of water in motion is not more admissible than in the preceding instances. Thus we arrive at the conclusion, that if Nature sometimes forms crystals with perfect terminations in magmas in the course of solidification, she gives rise also to spheroidal forms surrounding various centres, which sometimes originate spontaneously, and in other cases are accumulated round the dÉbris of fossils, or even mere grains of sand. Nevertheless, all mineral substances are not alike calculated to produce oolitic rocks; putting aside some particular cases, this property is confined to limestone and oxide of iron. With regard to the distribution of the Jurassic formation on the terrestrial globe, it may be stated that the Cotteswold Hills in England, and in France the Jura mountains, are almost entirely composed of these rocks, the several series of beds being all represented in them—this circumstance, in fact, induced Von Humboldt to name the formation after this latter range. The Upper Lias also exists in the Pyrenees and in the Alps; in Spain; in many parts of Northern Italy; in Russia, especially in the government of Moscow, and in the Crimea; but it is in Germany where it occupies the most important place. A thin bed of oolitic limestone presents, at Solenhofen in Bavaria, a geological repository of great celebrity, containing fossil Plants, Fishes, Insects, Crustaceans, with some Pterodactyles, admirably preserved; it yielded also some of the earliest of the feathered race. The fine quarries of lithographic stone at Pappenheim, so celebrated all over Europe, belong to the Jurassic formation. In England the Lias constitutes a well-defined belt about thirty miles broad, extending from Dorsetshire, in the south, to Yorkshire, in the north, formed of alternate beds of clay, shales, and limestone (with layers of jet), on the coast near Whitby. It is rich, as we have seen, in ancient life, and that in the strongest forms imaginable. From the unequal hardness of the rocks it comprises, it stands out boldly in some of the minor ranges of hills, adding greatly to the picturesque beauty of the scenery in the centre of the country. In Scotland the formation occupies a very limited space. A map of the country at the close of the Jurassic period would probably show double the extent of dry land in the British Islands, compared with what it displayed as an island in the primordial ocean; but Devon and Cornwall had long risen from the sea, and it is probable that the Jurassic beds of Dorsetshire and France were connected by a tongue of land running from Cherbourg to the Liassic beds of Dorsetshire, and that Boulogne, still an island, was similarly connected with the Weald. Fig. 125.—Crioceras Duvallii, Sowerby. These sections, published by the Geological Survey, show in detail the beds in their regular and natural order of succession, with the thickness, mineral character, and contents, as well as the fossils, of each separate bed. THE CRETACEOUS PERIOD.The name Cretaceous (from creta, chalk) is given to this epoch in the history of our globe because the rocks deposited by the sea, towards its close, are almost entirely composed of chalk (carbonate of lime). Carbonate of lime, however, does not now appear for the first time as a part of the earth’s crust; we have already seen limestone occurring, among the terrestrial materials, from the Silurian period; the Jurassic formation is largely composed of carbonate of lime in many of its beds, which are enormous in number as well as extent; it appears, therefore, that in the period called Cretaceous by geologists, carbonate of lime was no new substance in the constitution of the globe. If geologists have been led to give this name to the period, it is because it accords better than any other with the characteristics of the period; with the vast accumulations of chalky or earthy limestone in the Paris basin, and the beds of so-called Greensand, and Chalk of the same age, so largely developed in England. We have already endeavoured to establish the origin of lime, in speaking of the Silurian and Devonian periods, but it may be useful to recapitulate the explanation here, even at the risk of repeating ourselves. We have said that lime was, in all probability, introduced to the globe by thermal waters flowing abundantly through the fissures, dislocations, and fractures in the ground, which were themselves caused by the gradual cooling of the globe; the central nucleus being the grand reservoir and source of the materials which form the solid crust. In the same manner, therefore, as the several eruptive substances—such as granites, porphyries, trachytes, basalts, and lava—have been ejected, so have thermal waters charged with carbonate of lime, and often accompanied by silica, found their way to the surface in great abundance, through the fissures, fractures, and dislocations in the crust of the earth. We need only mention here the Iceland geysers, the springs of PlombiÈres, and the well-known thermal springs of Bath and elsewhere in this country. But how comes lime in a state of bicarbonate, dissolved in these During the primary geological periods, thermal waters, as they reached the surface, were discharged into the sea and united themselves with the waves of the vast primordial ocean, and the waters of the sea became sensibly calcareous—they contained, it is believed, from one to two per cent. of lime. The innumerable animals, especially Zoophytes, and Mollusca with solid shells, with which the ancient seas swarmed, secreted this lime, out of which they built up their mineral dwelling—or shell. In this liquid and chemically calcareous medium, the Foraminifera and Polyps of all forms swarmed, forming an innumerable population. Now what became of the bodies of these creatures after death? They were of all sizes, but chiefly microscopic; that is, so small as to be individually all but invisible to the naked eye. The perishable animal matter disappeared in the bosom of the waters by decomposition, but there still remained behind the indestructible inorganic matter, that is to say, the carbonate of lime forming their testaceous covering; these calcareous deposits accumulating in thick beds at the bottom of the sea, became compacted into a solid mass, and formed a series of continuous beds superimposed on each other. These, increasing imperceptibly in the course of ages, ultimately formed the rocks of the Cretaceous period, which we have now under consideration. These statements are not, as the reader might conceive from their nature, a romantic conception invented to please the imagination of those in search of a system—the time is past when geology should be regarded as the romance of Nature—nor has what we advance at all the character of an arbitrary conception. One is no doubt struck with surprise on learning, for the first time, that all the limestone rocks, all the calcareous stones employed in the construction of our dwellings, our cities, our castles and cathedrals, were deposited in the seas of an earlier world, and are only composed of an aggregation of shells of Mollusca, or fragments of the testaceous coverings of Foraminifera and other Zoophytes—nay, that they were secreted from the water itself, and then assimilated by these minute creatures, and that this would appear to have been the great object of their creation in such myriads. Whoever will take the trouble to observe, and reflect on what he observes, will find all his doubts vanish. If chalk be examined with a microscope, it will be found to be composed of the remains of numerous Zoophytes, of minute and divers kinds of shells, and, above all, of Foraminifera, so small that their very minuteness seems to have rendered them indestructible. A Chalk under the Microscope. Fig. 126Fig. 126.—Chalk of Meudon (magnified). Much of this curious information was unknown, or at least only suspected, when Ehrenberg began his microscopical investigations. From small samples of chalk reduced to powder, placed upon the object-glass, and examined under the microscope, Ehrenberg prepared the designs which we reproduce from his learned micrographical work, in which some of the elegant forms discovered in the Chalk are illustrated, greatly magnified. Fig. 126 represents the chalk of Meudon, in France, in which ammonite-like forms of Foraminifera and others, equally beautiful, appear. Fig. 127, from the chalk of Gravesend, contains similar objects. Fig. 128 is an example Chalk under the Microscope. Fig. 127Fig. 127.—Chalk of Gravesend. (After Ehrenberg).—Magnified. Observation, then, establishes the truth of the explanation we have given concerning the formation of the chalky or Cretaceous rocks; but the question still remains—How did these rocks, originally deposited in the sea, become elevated into hills of great height, with bold escarpments, like those known in England as the North and South Downs? The answer to this involves the consideration of other questions which have, at present, scarcely got beyond hypothesis. Chalk under the Microscope. Fig. 128Fig. 128.—Chalk of the Isle of MoËn, Denmark. Chalk under the Microscope. Fig. 129Fig. 129.—Chalk of Cattolica, Sicily (magnified). The proof that the Wealden series were accumulated under fresh-water conditions and as a river deposit After these explanations as to the manner in which the cretaceous rocks were formed, let us examine into the state of animal and vegetable life during this important period in the earth’s history. The vegetable kingdom of this period forms an introduction to the vegetation of the present time. Placed at the close of the Secondary epoch, this vegetation prepares us for transition, as it were, to the vegetation of the Tertiary epoch, which, as we shall see, has a great affinity with that of our own times. The landscapes of the ancient world have hitherto shown us some species of plants of forms strange and little known, which are now extinct. But during the period whose history we are tracing, the vegetable kingdom begins to fashion itself in a less mysterious manner; Palms appear, and among the regular species we recognise some which differ little from those of the tropics of our days. The dicotyledons increase slightly in number amid Ferns and Cycads, which have lost much of their importance in numbers and size; we observe an obvious increase in the dicotyledons of our own temperate climate, such as the alder, the wych-elm, the maple, and the walnut, &c. “As we retire from the times of the primitive creation,” says Lecoq, “and slowly approach those of our own epoch, the sediments seem to withdraw themselves from the polar regions and restrict themselves to the temperate or equatorial zones. The great “Hitherto two classes of vegetation predominated: the cellular Cryptogams at first, the dicotyledonous Gymnosperms afterwards; and in the epoch which we have reached—the transition epoch of vegetation—the two classes which have reigned heretofore become enfeebled, and a third, the dicotyledonous Angiosperms, timidly take possession of the earth—they consist at first of a small number of species, and occupy only a small part of the soil, of which they afterwards take their full share; and in the succeeding periods, as in our own times, we shall see that their reign is firmly established; during the Cretaceous period, in short, we witness the appearance of the first dicotyledonous Angiosperms. Some arborescent Ferns still maintain their position, and the elegant Protopteris Singeri, Preissl., and P. Buvigneri, Brongn., still unfold their light fronds to the winds of this period. Some Pecopteri, differing from the Wealden species, live along with them. Some Zamites, Cycads, and Zamiostrobi announce that in the Cretaceous period the temperature was still high. New Palms show themselves, and, among others, Flabellaria chamÆropifolia is especially remarkable for the majestic crown at its summit. “The Conifers have endured better than the CycadeÆ; they formed then, as now, great forests, where Damarites, Cunninghamias, Araucarias, Eleoxylons, Abietites, and Pinites remind us of numerous forms still existing, but dispersed all over the earth. “From this epoch date the Comptonias, attributed to the MyricaceÆ; Almites Friesii, Nils., which we consider as one of the BetulaceÆ; Carpinites arenaceus, Goep., which is one of the CupuliferÆ; the Salicites, which are represented to us by the arborescent willows; the AcerinÆ would have their Acerites cretaceÆ, Nils., and the JuglanditÆ, the Juglandites elegans, Goep. But the most interesting botanical event of this period is the appearance of the Credneria, with its triple-veined leaves, of which no less than eight species have been found and described, but whose place in the systems of classification still remains uncertain. The Crednerias, like the Salicites, were certainly trees, as were most of the species of this remote epoch.” In the following illustration are represented two of the Palms belonging to the Cretaceous period, restored from the imprints and fragments of the fossil remains left by the trunk and branches in the rocks of the period (Fig. 130.) Fig. 130.—Fossil Palms restored. It is not without surprise that we advert to the immense development, the extraordinary dimensions which the Saurian family attained at this epoch. These animals which, in our days, rarely exceed a yard or so in length, attained in the Cretaceous period as much as twenty. The marine lizard, which we notice under the name of Mosasaurus, was then the scourge of the seas, playing the part of the Ichthyosauri of the Jurassic period; for, from the age of the Lias to that of the Chalk, the Ichthyosauri, the Plesiosauri, and the Teleosauri were, judging from their organisation, the tyrants of the waters. They appear to have become extinct at the close of the Cretaceous period, and to give place to the Mosasaurus, to whom fell the formidable task of keeping within proper limits the exuberant production of the various tribes of Fishes and Crustaceans which inhabited the seas. This creature was first discovered in the celebrated rocks of St. Peter’s Mount at Maestricht, on the banks of the Meuse. The skull alone was about four feet in length, while the entire skeleton of Iguanodon Mantelli, discovered by Dr. Mantell in the Wealden strata, has since been met with in the Hastings beds of Tilgate Forest, measuring, as Professor Owen estimates, between fifty and sixty feet in length. These enormous Saurians disappear in their turn, to be replaced in the seas of the Tertiary epoch by the Cetaceans; and henceforth animal life begins to assume, more and more, the appearance it presents in the actually existing creation. Seeing the great extent of the seas of the Cretaceous period, Fishes were necessarily numerous. The pike, salmon, and dory The sea was still full of Polyps, Sea-urchins, Crustaceans of various kinds, and many genera of Mollusca different from those of the Jurassic period; alongside of gigantic Lizards are whole piles of animalculÆ—those Foraminifera whose remains are scattered in infinite profusion in the Chalk, over an enormous area and of immense thickness. The calcareous remains of these little beings, incalculable in number, have indeed covered, in all probability, a great part of the terrestrial surface. It will give a sufficient idea of the importance of the Cretaceous period in connection with these organisms to state that, in the rocks of the period, 268 genera of animals, hitherto unknown, and more than 5,000 species of special living beings have been found; the thickness of the rocks formed during the period being enormous. Where is the geologist who will venture to estimate the time occupied in creating and destroying the animated masses of which this formation is at once both the cemetery and the monument? For the purposes of description it will be convenient to divide the Cretaceous series into lower and upper, according to their relative ages and their peculiar fossils. The Lower Cretaceous Period.
The Lower Wealden or Hastings Sand consists of sand, sandstone, and calciferous grit, clay, and shale, the argillaceous strata predominating. This part of the Wealden consists, in descending order, of:—
The Hastings sand has a hard bed of white sand in its upper part, whose steep natural cliffs produce the picturesque scenery of the “High rocks” of Hastings in Sussex. Calcareous sandstone and grit, in which Dr. Mantell found the remains of the Iguanodon and HylÆosaurus, form an upper member The overlying Weald clay crops out from beneath the Lower Greensand in various parts of Kent and Sussex, and again in the Isle of Wight, and in the Isle of Purbeck, where it reappears at the base of the chalk. The upper division (or the Weald clay) is, as we have said, of purely fresh-water origin, and is supposed to have been the estuary of some vast river which, like the African Quorra, may have formed a delta some hundreds of miles broad, as suggested by Dr. Dunker and Von Meyer. The Lower Greensand is known, also, as the NÉocomien, after Neocomium, the Latin name of the city of Neufchatel, in Switzerland, where this formation is largely developed, and where, also, it was first recognised and established as a distinct formation. Dr. Fitton, in his excellent monograph of the Lower Cretaceous formations, gives the following descending succession of rocks as observable in many parts of Kent:—
These divisions, which are traceable more or less from the southern part of the Isle of Wight to Hythe in Kent, present considerable variations. At Atherfield, where sixty-three distinct strata, measuring 843 feet, have been noticed, the limestone is wholly wanting, and some fossils range through the whole series, while others are confined to particular divisions; but Prof. E. Forbes states, that when the same conditions are repeated in overlying strata the same species reappear; but that changes of depth, or of the mineral nature of the sea-bottom, the presence or absence of lime or of peroxide of iron, the occurrence of a muddy, sandy, or gravelly bottom, are marked by the absence of certain species, and the predominance of others. Fig. 131.—Perna Mulleti. One-quarter natural size. Among the marine fauna of the NÉocomian series the following The Scaphites have a singular boat-shaped form, wound with contiguous whorls in one part, which is detached at the last chamber, and projects in a more or less elongated condition. Fig. 132.—Hamites. One-third natural size. Hamites, Crioceras, and Ancyloceras have club-like terminations at Fig. 133.—Shell of Turritella terebra. The Toxoceras had the shell also curved, and not spiral. The Baculites had the shell differing from all Cephalopods, inasmuch Fig. 134.—Turrillites costatus. The Turrilites have the shell regular, spiral, and sinistral; that is, turning to the left in an oblique spiral of contiguous whorls. The engraving will convey the idea of their form (Fig. 134). Fig. 135—Terebrirostra lyra. Among others, as examples of form, we append Figs. 133, 135, 136. Fig. 136.—Terebratula deformis. This analysis of the marine fauna belonging to the NÉocomian formation might be carried much further, did space permit, or did it promise to be useful; but, without illustration, any further merely verbal description would be almost valueless. Numerous Reptiles, a few Birds, among which are some “Waders,” belong to the genera of PalÆornis or Cimoliornis; new Molluscs in considerable quantities, and some extremely varied Zoophytes, constitute the rich fauna of the Lower Chalk. A glance at the more important of these animals, which we only know in a few mutilated fragments, is all our space allows; they are true medals of the history of our globe, medals, it is true, half effaced by time, but which consecrate the memory of departed ages. In the year 1832 Dr. Mantell added to the wonderful discoveries he had made in the Weald of Sussex, that of the great Lizard-of-the-woods, the hylÆosaurus (???, wood, sa????, lizard). This discovery was made in Tilgate forest, near Cuckfield, and the animal appears to have been from twenty to thirty feet in length. The osteological characters presented by the remains of the HylÆosaurus are described by Dr. Mantell as affording another example of the blending of the Crocodilian with the Lacertian type of structure; for we have, in the pectoral arch, the scapula or omoplate of a crocodile associated with the coracoid of a lizard. Another remarkable feature in these fossils is the presence of the large angular bones or spines, which, there is reason to infer, constituted a serrated crest along the The Megalosaurus, the earliest appearance of which is among the more ancient beds of the Liassic and Oolitic series, is again found at the base of the Cretaceous rocks. It was, as we have seen, an enormous lizard, borne upon slightly raised feet; its length exceeded forty feet, and in bulk it was equal to an elephant seven feet high. Fig. 137.—Lower Jaw of the Megalosaurus. Fig. 138.—Tooth of Megalosaurus. The Megalosaurus found in the ferruginous sands of Cuckfield, in Sussex, in the upper beds of the Hastings Sands, must have been at least sixty or seventy feet long. Cuvier considered that it partook both of the structure of the Iguana and the Monitors, the latter of which belong to the Lacertian Reptiles which haunt the banks of the Nile and tropical India. The Megalosaurus was probably an amphibious Saurian. The complicated structure and marvellous arrangement of the teeth prove that it was essentially carnivorous. It fed probably on other Reptiles of moderate size, such as the Crocodiles and Turtles which are found in a fossil state in the same beds. The jaw represented in Fig. 137 is the most important fragment of the animal we possess. It is the lower jaw, and supports many teeth: it shows that the head terminated in a straight muzzle, thin and flat on the sides, like that of the Gavial, the Crocodile of India. The teeth of the Megalosaurus were in perfect accord with the destructive functions Fig. 139.—Nasal Horn of Iguanodon. Fig. 140.—Ammonites rostratus. The Iguanodon, signifying Iguana-toothed (from the Greek word, ?d???, tooth), was more gigantic still than the Megalosaurus; one of the most colossal, indeed, of all the Saurians of the ancient world which The Iguanodon carried, as we have said, a horn on its muzzle; the bone of its thigh, as we have seen, surpassed that of the Elephant in size; the form of the bone and feet demonstrates that it was formed for terrestrial locomotion; and its dental system shows that it was herbivorous. Fig. 141.—Teeth of Iguanodon. Fig. 142.—Fishes of the Cretaceous period. The Cretaceous seas contained great numbers of Fishes, among which some were remarkable for their strange forms. The Beryx Lewesiensis (1), and the Osmeroides Mantelli (2) (Fig. 142), are restorations of these two species as they are supposed to have been in life. The Odontaspis is a new genus of Fishes which may be mentioned. Ammonites rostratus (Fig. 140), and Exogyra conica (Fig. 147), are common shells in the Upper Greensand. XXI.—Ideal scene in the Lower Cretaceous Period, with Iguanodon and Megalosaurus. On the opposite page an ideal landscape of the period is represented (Plate XXI.), in which the Iguanodon and Megalosaurus struggle for the mastery in the centre of a forest, which enables us also to convey some idea of the vegetation of the period. Here we note a vegetation at once exotic and temperate—a flora like that of the tropics, and also resembling our own. On the left we observe a group of trees, which resemble the dicotyledonous plants of our forests. The elegant Credneria is there, whose botanical place is still doubtful, for its fruit has not been found, although it is believed to have belonged to plants with two seed-leaves, or dicotyledonous, and the arborescent AmentaceÆ. An entire group of trees, composed of Ferns and Zamites, are in the background; in the extreme distance are some Palms. We also recognise in the picture the alder, the wych-elm, the maple, and the walnut-tree, or at least species analogous to these. The NÉocomian beds in France are found in Champagne, in the departments of the Aube, the Yonne, the Haute-Alps, &c. They are largely developed in Switzerland at Neufchatel, and in Germany. 1. The Lower NÉocomian consists of marls and greyish clay, alternating with thin beds of grey limestone. It is very thick, and occurs at Neufchatel and in the DrÔme. The fossils are Spatangus retusus, Crioceras (Fig. 125), Ammonites Asterianus, &c. 2. Orgonian (the limestone of Orgon). This group exists, also, at Aix-les-Bains in Savoy, at Grenoble, and generally in the thick, white, calcareous beds which form the precipices of the DrÔme. The fossils Chama ammonia, Pigaulus, &c. 3. The Aptien (or Greensand) consists generally of marls and clay. In France it is found in the department of Vaucluse, at Apt (whence the name Aptien), in the department of the Yonne, and in the Haute-Marne. Fossils, Ancyloceras Matheronianus, Ostrea aquila, Fig. 143.—Cypris spinigera. We have noted that the Lower NÉocomian formation, although a marine deposit, is in some respects the equivalent of the Weald Clay, a fresh-water formation of considerable importance on account of its fossils. We have seen that it was either formed at the mouth of a great river, or the river was sufficiently powerful for the fresh-water current to be carried out to sea, carrying with it some animals, forming a fluviatile, or lacustrine fauna, on a small scale. These were small Crustaceans of the genus Cypris, with some molluscous Gasteropoda of the genera Melania, Paludina, and acephalous Mollusca of the five genera Cyrena, Unio, Mytilus, Cyclas, and Ostrea. Of these, Cypris spinigera (Fig. 143) and Cypris Valdensis (Fig. 144) may be considered as among the most characteristic fossils of this local fauna. Fig. 144.—Cypris Valdensis. The Cretaceous series is not interesting for its fossils alone; it presents also an interesting subject for study in a mineralogical point of view. The white Chalk, examined under the microscope by Ehrenberg, shows a curious globiform structure. The green part of its sandstone and limestone constitutes very singular compounds. According to the result of Berthier’s analysis, we must consider them as silicates of iron. The iron shows itself here not in beds, as in the Jurassic rocks, but in masses, in a species of pocket in the Orgonian beds. They are usually hydrates in the state of hematites, accompanied by quantities of ochre so abundant that they are frequently unworkable. In the south of France these veins were “This state of things could not last; and in 1848 it was curious to see miners suspended on the sides of one of these lateral precipices, some 450 feet above the torrent, and about an equal distance below the summit of the Chalk. There they began to excavate cavities or niches in the face of the rock, all placed on the same level, and successively enlarged. These were united together in such a manner as to form a road practicable for carriages; now through a gallery, now covered by a corbelling, to look over which affords a succession of surprises to the traveller. “This is not all,” adds M. Fournet: “he who traverses the high plateaux of the country finds at every step deep diggings in the soil, designated pits or scialets, the oldest of which have their sides clothed with a curious vegetation, in which the Aucolin predominates; shelter is found in these pits from the cutting winds which rage so furiously in these elevated regions. Others form a kind of cavern, in which a temperature obtains sufficient to freeze water even in the middle of summer. These cavities form natural glaciers, which we again find upon some of the table-lands of the Jura. “The cracks and crevasses of the limestone receive the waters produced by falling rain and melted snow; true to the laws of all fluid bodies, they filter through the rocks until they reach the lower and impervious marly beds, where they form sheets of water, which in course of time find some outlet through which they discharge themselves. In this manner subterranean galleries, sometimes of great extent, are formed, in which are assembled all the marvels which crumbling stalactites, stalagmites, placid lakes, and headlong torrents can produce; finally, these waters, forcing their way through the external orifices, give rise to those fine cascades which, with the first gushing torrent, form an actual river.” Upper Cretaceous Period.During this phase of the terrestrial evolutions, the continents, to judge from the fossilised wood which we meet with in the rocks which now represent it, would be covered with a very rich vegetation, nearly identical, indeed, with that which we have described in the preceding sub-period; according to Adolphe Brongniart, the “age of angiosperms” had fairly set in; the Cretaceous flora displays, he considers, a transitional character from the Secondary to the Tertiary vegetation; that the line between the gymnosperms, or naked-seeded plants, and the angiosperms, having their seeds enclosed in seed-vessels, runs between the Upper and Lower Cretaceous formations. “We can now affirm,” says Lyell, “that these Aix-la-Chapelle plants, called Credneria, flourished before the rich reptilian fauna of the secondary rocks had ceased to exist. The Ichthyosaurus, Pterodactyle, and Mosasaurus were of coeval date with the oak, the walnut, and the fig.” The terrestrial fauna, consisting of some new Reptiles haunting the banks of rivers, and Birds of the genus Snipe, have certainly only reached us in small numbers. The remains of the marine fauna are, on the contrary, sufficiently numerous and well preserved to give us a great idea of its riches, and to enable us to assign to it a characteristic facies. The sea of the Upper Cretaceous period bristled with numerous submarine reefs, occupying a vast extent of its bed—reefs formed of “It seems,” says Alcide D’Orbigny, “as if the sea had retired in order to show us, still intact, the submarine fauna of this period, such as it was when in life. There are here enormous groups of Hippurites in their places, surrounded by Polyps, Echinoderms, and Molluscs, which lived in union in these animal colonies, analogous to those which still exist in the coral-reefs of the Antilles and Oceania. In order that these groups should have been preserved intact, they must first have been covered suddenly by sediment, which, being removed by the action of the atmosphere, reveals to us, in their most secret details, this Nature of the past.” In the Jurassic period we have already met with these isles or reefs formed by the accumulation of Coral and other Zoophytes; they even constituted, at that period, an entire formation called the Coral-rag. The same phenomenon, reproduced in the Cretaceous seas, gave rise to similar calcareous formations. We need not repeat what we have said already on this subject when describing the Jurassic period. The coral or madrepore isles of the Jurassic epoch and the reefs of Rudistes and Hippurites of the Cretaceous period have the same origin, and the atolls of Oceania are reproductions in our own day of precisely similar phenomena. The invertebrate animals which characterise the Cretaceous age are among Cephalopoda. Nautilus sublÆvigatus and N. Danicus; Ammonites rostratus; Belemnitella mucronata. Gasteropoda. Voluta elongata; Phorus canaliculatus; Nerinea bisulcata; Pleurotomaria Fleuriausa, and P. Santonensis; Natica supracretacea. Acephala. Trigonia scabra; Inoceramus problematicus and I. Lamarckii; Clavigella cretacea; Pholadomya Æquivalvis; Spondylus spinosus; Ostrea vesicularis; Ostrea larva; Janira quadricostata; Arca Gravesii; Hippurites Toucasianus and H. organisans; Caprina Aguilloni; Radiolites radiosus, and R. acuticostus. Brachiopoda. Crania Ignabergensis; Terebratula obesa. Polyzoa (Bryozoa) and Eschinodemata. Reticulipora obliqua; Ananchytes ovatus; Micraster cor-anguinum, Hemiaster bucardium and H. Fourneli; Galerites albogalerus; Cidaris Forchammeri; PalÆocoma Furstembergii. 1. Polypi; 2. Foraminifera; 3. Amorphozoa. 1. Cycollites elliptica; Thecosmilia rudis; Enallocoenia 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 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, 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 Fig. 145. 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 Fig. 146.—Head of Mosasaurus Camperi. 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. XXII.—Ideal Landscape of the Cretaceous Period. 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 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. 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 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 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. Fig. 147.—Exogym conica. Upper Greensand and Gault, from Blackdown Hill. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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