browsed in the virgin forest; lizards (lacerta and macellodus) basked on the sunny cliffs; and bird-like genera (pterodacty Restored forms of Megalosaurus and Hylaeosaurus-HAWKINS. lus) winged the upper firmament. Every adaptation of form and function finds its exemplar in these ancient saurians, and the part now played by birds and mammals was then in a great measure discharged by reptiles. They were the representatives in time of the higher orders of vitality— occupying every habitat, aquatic, terrestrial, and aerial, and fulfilling every function, herbivorous, carnivorous, and omnivorous. Everywhere they are the dominant forms, and though birds and mammals are coming more clearly on the stage, the great vital phase of creation was, for the time being, unmistakably reptilian. This "Reign of Reptiles," as it is sometimes termed, has suggested to minds, more imaginative than logical, the idea of an epoch of incessant warfare and murder; and nothing is more common than pictorial delineations and high-wrought descriptions of reptilian carnage and cruelty. Transferring the attributes of the infuriated human mind. to the unreasoning brute, they picture every species lying in wait for his neighbour-writhing in savage combat for supremacy, and mangling with their horrid fangs even where prey does not become a necessity. Alas! for man's mistaken notion of creation's life-scheme; as if, even in a world of reptiles, there were not a thousand checks and compensations ever actively at work to secure the greatest happiness of the greatest numbers. No doubt the flesheater preyed on the plant-eater, and the weak succumbed where the strong exulted; but death comes unconsciously quick where the preyer strikes from necessity, and the fall of the sickly gives wider verge to the enjoyment of the healthy survivor. The wants of nature supplied, and then, as now, the gigantic herbivora rolled sportively. among the over-topping herbage, or stood drowsily dreaming under the shade of the noonday forest; while the carnivora gambolled in the open waters, or lazily sunned themselves on the ebbing sea-shore. Wherever life prevails, there also is meted out to it its measure of enjoyment, and man only errs when, describing the lower animals, he invests them with passions and feelings unfortunately too frequently his own. But cold-blooded air-breathers, however varied in size, form, and function, were not destined to be the culminating orders in the world's life-scheme. The divine creational idea, fixed from the beginning, was steadily evolving itself into higher and higher types; and along with this overwhelming exuberance of reptiles, the line of triassic birds was continued in such forms as palæornis (ancient-bird), while in certain areas there appeared the higher manifestations of mammalian development. Small insectivorous quadrupeds-amphitherium (doubtful-beast), phascolotherium (pouched-beast), stereognathus (thick-jaw), plagiaulax (oblique-grooved tooth), &c.-have been detected in the upper oolite, apparently marsupial in their structure, and pointing to the wombats, bandicoots, and phalangers of Australia as their nearest living analogues. From the number of these imbedded in a few square yards of a stratum near Swanage in Dorsetshire, we may confidently look forward to the discovery of many other mammalian forms— every condition of the period being favourable to the development of such a fauna. 1 3 2 Oolitic Mammals, natural size-1, Lower Jaw and Teeth of Phascolotherium ; Such are the phases of oolitic life, and such the conditions of sea and land, which its miscellaneous sediments seem to imply. Continuous lands of ample area for the growth of a varied flora, open free-flowing seas for an exuberant marine fauna, gigantic estuaries and river plains for the amphibious reptiles of the Weald, and over all a genial but periodically interrupted climate. We have as yet no means of determining the universal climatology of the period, but over the oolitic areas of the northern hemisphere the varying rings of coniferous growth would seem to indicate seasonal variations, while the prevailing aspect of the flora, the abundance of land reptiles, and the presence of small marsupials, point to conditions of general warmth and periodic drought, such as now obtain over the riverless plains of Australia. As in its external, so in its vital conditions the oolitic epoch finds its newest analogue in the flora and fauna of the Australasian continent, thus indicating once more the connection that invariably subsists between the manifestations of life, and the conditions by which they are surrounded. "The close approximation," remarks Professor Owen, "of the amphitherium and phascolotherium to marsupial genera, now confined to New South Wales and Van Dieman's Land, leads us to reflect upon the interesting correspondence between other organic remains of the British oolite and other existing forms now confined to the Australian continent and adjoining seas. Here, for example, swims the cestracion which has given the key to the nature of the palates from our oolite, now recognised as the teeth of congeneric gigantic forms of cartilaginous fishes. Not only trigoni, but living terebratulæ exist, and the latter abundantly, in Australian seas, yielding food to the cestracion, as their extinct analogues doubtless did to the allied cartilaginous fishes called acrodi, psammodi, &c. Araucaria and cycadaceous plants likewise flourish on the Australian continent, where marsupial quadrupeds abound, and thus appear to complete a picture of an ancient condition of the earth's surface, which has been superseded in our hemisphere by other strata, and a higher type of mammalian organisation." This picture, however, must be received as nothing more than the merest analogy. Nature never repeats herself in time any more than in space, and forms once gone disappear for ever. To speak, as some have done, of Australia being "a belated portion of the earth's surface," is altogether to misinterpret the scheme of creational progress. The species of the oolite are not the species of Australia, while fossil evidence already shows that the present races of the Austral islands have had their gigantic tertiary predecessors, just as other regions have had theirs, and this in a genetic line backwards through the prior epochs of the chalk and oolite. In some of its minor features the oolite may find an analogue in existing nature, but in its entirety it stands alone-a great life-epoch, whose forms are not to be confounded either with what has gone before, or with what has yet to follow. The Cretaceous or Chalk period, to which we next turn, brings to a close the long and exuberant line of mesozoic life. Great changes in the relative distribution of sea and land in the northern hemisphere have been gradually brought about; much of the oolitic sea-bed has become dry land; and the areas of deposit have assumed a less southerly aspect. Stretching more in an easterly and westerly direction, they present less variety of climate, and, opening up to the north, they become recipients of currents which tend to deteriorate the more genial conditions of the oolitic era. Greensands, clays, clay-marls, and chalk of varying consistence form the prevailing sediments, which, being eminently marine, are replete with the remains of oceanic life. Little of the terrestrial surface of the period is indicated by the fossil flora or fauna, and much of the marine area in Asia and in America has been but imperfectly explored. Notwithstanding this imperfection of the record, we find enough to corroborate the ever-onward progression of vitality, and to show that oolitic forms, though by no means rare, are gradually being replaced by others peculiar to the chalk and greensand. The Flora, though scantily preserved, has still somewhat of an oolitic aspect, looking more like the remnants of that age than the peculiar products of a newer epoch. Sea-weeds (confervites and chondrites) resembling the living confervæ and Irish-moss, ferns (lonchopteris), lily-like leaves (drucana), cycads (zamiostrobus and clathraria), and coni |