Reader! pause and reflect upon this enumeration of the rocky strata, and their contents, which compose the Paris basin. What vast accumulations, now of terrestrial floods, now of inroads from the ocean—here a deposit, testifying to the fact of some great inland lake, with huge monsters browsing on its banks or reposing in its shallows—there another, bearing witness to “the strength of a mountain river,” combating with the waves of an estuary, and each wearying of the conflict and mingling their spoils from land and sea in one common mass. Neptune is again triumphant, and leaves as the trophies of victory whole families and tribes of his own domains. Silvanus now asserts and establishes his reign, and the Genet, Raccoon, Opossom, the Squirrel, Woodcock, and Buzzard are there to proclaim his sway. The Nereids too had their doings, and both genera and species of seven extinct nondescript fishes show their powers. And, last of all, come the Naïads of the streams, presenting you with their offering in the Quail, Curlew, and Pelican, along with Tortoises and Crocodilians. Count and enter upon your list, as found in the gypseous formation alone, eleven or twelve species of the Palæotherium, an animal partaking of the respective structures of the rhinoceros, the horse, and the tapir; of the Anoplotherium five species, commingling the light and graceful form of the gazelle with the conformation of the camel; fifteen species of the Lophiodon, closely allied to the former, but partaking also of the qualities of the hippopotamus; seven species of the Anthracotherium, a creature whose dimensions through the various members of the family swell out from the size of the hog to that of the hippopotamus; the Chæropotamus, allied to the suidæ, and forming a link between the Anoplotherium and the existing Peccary; and, lastly, as closing the list of this remarkable race of thick-skinned animals, we are presented with specimens of the Adapis, of hedgehog appearance, but in size three times larger, and uniting in characters the insectivorous carnivora with the Pachydermata.
It is recorded of Newton, that, toward the close of his wonderful calculations, when it seemed that the arithmetical results were to be in harmony with the dynamical problem to be solved, when he felt on the verge of determining one of the most important laws ever discovered by man, and which forever would bind the heavens to the earth—the nerves of the calculator gave way for a time, and he was unable to finish his task. He called in the aid of a friend, pacing the room in tumultuous agitation while the few last terms were being added. It is impossible for any other mind to realize the intensity of the geometer’s feelings when the result was announced! Knowing how trifling a novelty will at times agitate the finest minds, no wonder need be that Newton was affected by an uncontrollable tremor, when he saw that the discovery was made and tested, not only of the law that binds together the particles of matter which compose our earth, but also that which unites the heavenly orbs in all their majesty with the simplest of terrestrial phenomena; and demonstrates that, over the descent of a leaf in the forest—the drooping of a blade of grass—a pebble tossed upon the shore—a mote rising and falling in the sunbeam—a drop issuing from the rain-cloud—there is the same regulating power as that which retains the planets in their orbits, and determines their course through infinite space. Cuvier, in simple but eloquent words, has recorded, in the Introduction to his “Ossemens Fossiles,” the state of his feelings as he established his discoveries, and proceeded in his task of reconstructing his singular menagerie from the dry bones of Montmartre in the basin of Paris. “I at length,” he says, “found myself as if placed in a charnel-house, surrounded by mutilated fragments of many hundred skeletons, of more than twenty kinds of animals, piled confusedly around me; and the task assigned me was to restore them all to their original position. At the voice of comparative anatomy, every bone and fragment of a bone resumed its place. I cannot find words to express the pleasure I experienced in seeing, as I discovered one character, how all the consequences which I predicted from it were successively confirmed; the feet were found in accordance with the characters announced by the teeth; the teeth in harmony with those indicated beforehand by the feet; the bones of the legs and thighs, and every connecting portion of the extremities, were found set together precisely as I had arranged them before my conjectures were verified by the discovery of the parts entire; in short, each species was, as it were, reconstructed from a single one of its component elements.”
Cuvier proceeded upon the principle, that every organized individual forms an entire system of its own, all the parts of which mutually correspond, and that none of these separate parts can change their forms without a corresponding change on the other parts of the same individual body. Where the viscera, for example, are so constructed as only to be fitted for the digestion of recent flesh, it is requisite that the jaws should be so formed as to fit them for devouring prey—the claws for seizing and tearing it to pieces—the teeth for cutting and dividing its flesh—the limbs or organs of motion for pursuing and overtaking it—and the organs of sense for discovering it at a distance. But under this general principle in the structure of carnivorous animals, the ingenious anatomist further discovered that there are several particular modifications, depending upon the size, the manners, and the haunts of prey for which each species is destined or fitted by nature; and that, from each of these particular modifications, there result certain differences in the more minute conformations of particular parts. Hence it follows, that there will exist distinct indications in every one of their parts, not only of the classes and orders of animals, but also of their genera and species.
Thus, in order that the jaw may be well adapted for laying hold of objects, it is necessary that its condyle should have a certain form; that the resistance, the moving power, and the fulcrum, should all have a certain relative position with respect to each other. To enable the animal to carry off its prey when seized, a corresponding force is requisite in the muscles which elevate the head; and this again gives rise to a determinate form of the vertebræ to which these muscles are attached, and of the occiput into which they are inserted. The teeth of a carnivorous animal require to be sharp, in proportion to the greater or less quantity of flesh that they have to cut; their roots to be solid and strong, in proportion to the quantity and the size of the bones that have to be broken; and these conditions of structure will necessarily influence the development and form of the several parts that contribute to move the jaws.
The strength of the claws, in like manner, and the mobility of the paws and toes, have a necessary relation to the forms of the bones in the feet, and the distribution of the muscles and tendons by which they are moved. As the bones of the forearm are articulated with the humerus, no change can be made in the form and structure of the former without occasioning correspondent changes in the form of the latter. The shoulder-blade also, or scapula, requires a correspondent degree of strength in all carnivorous animals, while the play and action of the several parts are dependent on the muscles which set them in motion, and the impressions formed by these muscles still further determine the forms of all these bones. Again, the shape and structure of the teeth regulate the forms of the condyle, of the scapula, and of the claws, in the same manner as the equation of a curve regulates all its other properties;—and, as in regard to any particular curve, all its properties may be ascertained by assuming each separate property as the foundation of a particular equation, in the same manner a claw, a shoulder-blade, a condyle, a leg or arm bone, or any other bone separately considered, leads to the discovery of the characters of teeth to which they have belonged; and reciprocally from the teeth we are enabled to discover the structure and forms of the other bones.
Thus, conducting his investigations by a careful survey of the bones and organs individually and separately, the skillful anatomist was enabled to reconstruct the whole animal to which they severally had belonged. The orders likewise and subdivisions of herbivorous, ruminant, hoofed, and cloven-hoofed animals, he determined with equal precision, and found to result from the same constant laws of organization. By employing the method of observation, where theory was no longer able to direct his views, Cuvier was furnished with other astonishing results. The smallest fragment of bone, even the most apparently insignificant apophysis, he found to possess a fixed and determinate character, relative to the class, order, and genus of the animal to which it belonged; insomuch that, when he observed merely the articulating extremity of a well-preserved bone, he could at once ascertain the species as certainly as if the entire animal had been before him. Proceeding after this method, assisted by analogy and exact comparison, Cuvier has been enabled to determine the fossil remains of seventy-eight different quadrupeds, in the viviparous and oviparous classes. Of these, forty-nine are distinct species hitherto unknown, twenty-seven of which are referable to seven new genera, and the other twenty-two new species belong to sixteen genera, or sub-genera, already known; while the whole number of genera and sub-genera, to which the fossil remains of quadrupeds investigated belong, are thirty-six, including those both of known and unknown species; some hoofed animals not ruminant, and some ruminant—others gnawers and others carnivorous—two, of the sloth genus, toothless—and two, amphibious animals, of two distinct genera.
Such are the triumphs of science, which always lead to a profounder admiration of the works of Nature, in the immensity and constancy of those laws that have prevailed through all time, and where her wisdom and foresight are demonstrated by a series of systematic contrivances and mutual adaptations to which she invariably adheres. In the remote invisible depths of space, slight oscillations have from time to time been detected, and following up the researches, astronomy, as announced beforehand, is rewarded by the discovery of a new planet. The earth gives up its dead, entombed for ages in its stony matrix. At the bidding of science their figures are restored, their habits determined, their very food ascertained, their characters for ferocity or otherwise brought to light, and they are all, each after their kind, called by their names. What a mastery in all this over the extinct forms of organic nature, as Newton manifested in a different way in his wonderful deductions and calculations respecting the molecules of inorganic nature and the physical heavens!
III. The Paris basin, which consists of the lower or eocene series of the tertiary system, is inclosed nearly on all sides by the middle or miocene group of strata. These, however, are most fully developed along the district of the Loire and its tributaries, as the former are chiefly confined to the water-shed of the Seine and the environs of Paris. We thus advance a step upward in the Course of Creation, while so far as geology has been able to mark the progress, the last stages of the stupendous work, prior to the introduction of its noblest inhabitant, are to be discovered in the pleiocene deposits that immediately succeed, stretching over the western shores from Bordeaux to Bayonne.
The Basin of the Loire. The rocks which compose these upper layers of the earth’s crust, have all a family resemblance to the tertiaries already described. In the district of the Loire the miocene beds consist generally of quartzose sand, gravel, and broken shells, mostly loose and earthy, but in many places agglutinated by a calcareous or ferruginous cement, so as to be fit for building purposes. The “faluns,” as they are provincially termed, resemble the crag of England, abounding in shells, and mammiferous remains incrusted with serpulæ, flustra, and balani, The deposit is seldom above seventy feet in its greatest thickness. Betwixt Sologne and the sea, patches are found to rest successively upon gneiss, clayslate, the coal-measures, Jura limestone, greenstone trap, chalk, and the upper beds of the eocene series. The pleiocene beds are not materially different in their lithological characters from those of the miocene group: blue clays, marls, and osseous breccias are among the prevailing strata; and siltings of sand and gravel, only distinguishable by their organic remains from the alluvia and superficial drifts of the current era. Volcanic products are often largely mixed up with these pleiocene beds, and in districts where, in addition to the fossil evidence, they clearly establish that they belong to the class of extinct volcanoes, as the sedimentary deposits are themselves determined to belong to the pleiocene age.
