And these three blessings all are striving to maintain, to restore, or to acquire. Life, health, pleasure—these are the great stimulants to all human exertion, and how best to promote them ought to be the aim of human study. The suite of rocks which compose the carboniferous system is one clearly of pre-arrangement, and designed for man’s use. The strata, now beneath us, as undeniably evince a like beneficent purpose. The treasures of saline rock, gypseous marls, iron sands, and pyritous clays, may be mysterious all, in their origin: but their uses and their ends, human wants and frailties have long since established. The cravings of appetite satisfied, every creature has an instinct, which unerringly leads it to seek a remedy against injury and disease; and a provision for the one equally with the other, has been made by Him who notices the sparrow in his fall, and careth for the ravens of the desert. Slow of apprehension the mind, that cannot discern in the strata under review, a striking instance of foresight, a gift of benevolent wisdom, recesses long since stored with medicaments and restoratives for human frailties; and, though no angel now is there to trouble the waters, a kind Providence has designed them, and a good heart will use them, as tokens of its love.
II. The Organic Remains are chiefly of a fluviatile and terrestrial character. The beds in which they occur were deposited in the channel, or delta, of a river of great breadth, and demonstrate the existence of a large extent of neighboring country. These beds range from Hastings into Dorsetshire, but are not found to the north of the Thames. In Portland and the Isle of Wight they likewise exist with all their peculiar organisms in the greatest abundance. In the latter locality, the wealden beds form the cliffs between Atherfield Point and Compton Bay; they also overhang the Bay of Sandown. The Purbeck beds and sands are well displayed at Durdle Cove, Warbarrow, and Swanage Bays; and in the Vale of Wardour the same strata are developed. In every one of these beautiful, picturesque, accessible, and very limited districts, you have congregated specimens of the fauna and flora of rivers, groves, forests, and plains, which have no longer a place on the terraqueous globe. Compared with the living or extinct races they constitute a chapter in natural history nowhere else to be seen or studied.
Thus of eight genera of plants in the wealden, there are only four common to it and the oolites, but not a single species. Of the hundreds of zoophytes in the older formation, not one occurs in the newer. Twenty genera of insects existed in the period of the wealden, one only of which is prolonged from the antecedent period of oolitic life; one new genus of Crustacean (the Cypris), and five species; while the conchifera have little in common, save the mytilus and unio, and both of which, generically, have been transmitted from the carboniferous era. The fishes of the wealden consist of seven genera, of which only one is new, the Sphenonchus. The reptilians amount to eleven genera, three of which present remains in the oolitic group, Cetiosaurus, Chelonia, and Megalosaurus—same species in both. The Cetiosaurus belongs to the whale race of animals, and it is singular to find the tribe exhibiting the same stupidity, or hardihood it may be, in forsaking, then as now, their briny element, and seeking a grave in the clays and sands of fresh water shoals! The Hylæosaurus and Iguanodon were both found in the Tilgate Forest beds, but have been noticed under the fauna of the oolite series, as probably living in the age of, as they approach so closely in structure and size to, the reptilian types of the deposit; frequenting the woods and pastures, while their mighty cotemporaries were following their instincts in the seas and lakes of the district.
It would thus appear that the close of the oolitic period of the earth’s history resembles the close of the carboniferous period, in the sudden transition from an exuberant to a remarkably barren display of vegetable fossils. In the comparative scantiness of the sauroid family of fishes, by which the outgoing of the coal era is likewise distinguished, we may fancy another point of analogy in the diminution of the monstrous reptilians that appears to have taken place after this series of deposits. May it be inferred that these two periods enjoyed a higher degree of temperature than has prevailed, either before or since, generally over the earth’s surface, and more certainly in these northern latitudes? Interred among the strata of both lie the remains of races, vegetable and animal, which have perished: and what we describe by kindred names are confined to climes and regions basking near the equator, and enlightened by other constellations. Then the alternating deposits of clay, lime, ironstone, coal, salt, gypsum, speak of lakes and estuaries, rolling rivers and high lands no longer existing in these parts. A few leaves of their annals are inscribed with forms of grotesque life, and stirring activities, which are there to attest the majesty of their revolutions. Geology, in little more than twenty years, has made the discovery, collected the facts, arranged and systematized the knowledge of the character and habits of the successive generations whose domain, whether of land or water, was so different from ours, and now all passed away.
A higher temperature, from central heat, will not explain these facts, for that should have prevailed more in the devonian, and still more in the silurian periods,—and of this we have no evidence. Appearances would rather support an opposite conclusion. The sweep of the comet again, resorted to upon occasions, may have destroyed, but could not maintain, such a state of things. A change of the polar axis, of the most inconsiderable extent, is demonstrated to be highly improbable, or almost impossible. And now, in the unwearied march of science, often baffled but never cast down, it has been announced as the probable solution of all the changes of the past, the progression of the whole solar system, whereby the earth, and all the sister planets, are dragged through infinite space, and brought successively within the sphere of new constellations—now in a hotter and now in a milder efflux of ether—combining its own with a more general movement in a universal whirl—and thus constantly subjected, in all its parts, to ever-varying external influences! This, at least, is the ingenious theory of M. Poisson, which, he thinks, will account for the central heat of the globe, dipped for a time into a burning atmosphere, and cooling off more rapidly on the surface, and will give a no less plausible explanation as to the extent and frequency of change effected on the surface. Geology and astronomy become, when viewed in this light, correlative sciences, and impart an illustrative interest to the researches of each other. The lofty flights of the one are brought down, as it were, to more earthly things; while the geologist, on the other hand, is lifted from his miry pit and downward studies, to meditate on the “sweet influences and bands” that harmonize and link all the planets in their orbits, and rejoices to see his own earth taking part in the eternal music of the spheres. He is pleased to believe, according to the view of the astronomer, that this ball of stone and clay enjoys at times a vitality all over, which warms and cherishes into life natant forms, and creeping things, and flying dragons, whose development of powers could not have been sustained, on so great a scale, in the lower and less favored regions.
But while the cause may be adequate to the effect—and in the approximation to the truth there is a feeling of satisfaction, an elevation of vision and elasticity of thought, as
“Rays divine dart round the globe,”
—still the speculation referred to belongs rather to the poetry than to the philosophy of science, influencing the imagination more than the judgment, and trenching on relations that lie beyond the field of legitimate research.