[Ill.u.s.tration: Fig. 55.
LEBIAS CEPHALOTES.
Cycloids of Aix. (_Miocene._)]
[Ill.u.s.tration: Fig. 56.
PLATAX ALTISSIMUS.
A Ctenoid of Monte Bolca. (_Eocene._)]
And here let me adduce another and very remarkable instance of the correspondence which obtains between the sequence in which certain cla.s.ses of organisms were first ushered into being, and the order of cla.s.sification adopted, after many revisions, by the higher naturalists. Cuvier, with not a few of the ichthyologists who preceded him, arranged the fishes into two distinct series,--the Cartilaginous and Osseous; and these last he mainly divided into the hard or spiny-finned fishes, and the soft or joint-finned fishes. He placed the sturgeon in his Cartilaginous series; while in his soft-finned order he found a place for the Polypterus of the Nile and the Lepidosteus of the Ohio and St. Lawrence. But the arrangement, though it seemed at the time one of the best and most natural possible, failed to meet any corresponding arrangement in the course of geologic history. The place a.s.signed to the cla.s.s of fishes as a whole corresponded to their place in the Palaeontological scale;--- first of the vertebrate division in the order of their appearance, they border, as in the "_Animal Kingdom_" of the naturalist, on the invertebrate divisions. But it was not until the new cla.s.sification of Aga.s.siz had ranged them after a different fashion that the correspondence became complete in all its parts. First, he erected the fishes that to an internal cartilaginous skeleton unite an external armature of plates and points of bone, into his Placoid order; next, gathering together a mere handful of individuals from among the various orders and families over which they had been scattered,--the sturgeons from among the cartilaginous fishes, and the lepidosteus and polypterus from among the Clupia or herrings,--he erected into a small ganoid order all the fishes that are covered, whatever the consistency of their skeleton, by a continuous or nearly continuous armor of enamelled bone, or by great bony plates that lock into each other at their edges. Out of the remaining fishes,--those covered with scales of a h.o.r.n.y substance, and which now comprise nearly nine tenths of the whole cla.s.s,--he erected two orders more,--a Ctenoid order, consisting of fishes whose scales, like those of the perch, are pectinated at their lower edges like the teeth of a comb, and a Cycloid order, composed of fishes whose scales, like those of the salmon, are defined all around by a simple continuous margin; and no sooner was the division effected than it was found to cast a singularly clear light on the early history of the cla.s.s. The earliest fishes--firstborn of their family--seem to have been all placoids. The Silurian System has not yet afforded trace of any other vertebral animal. With the Old Red Sandstone the ganoids were ushered upon the scene in amazing abundance; and for untold ages, comprising mayhap millions of years, the entire ichthyic cla.s.s consisted, so far as is yet known, of but these two orders.
During the times of the Old Red Sandstone, of the Carboniferous, of the Permian, of the Tria.s.sic, and of the Oolitic Systems, all fishes, though apparently as numerous individually as they are now, were comprised in the ganoidal and placoidal orders. The period of these orders seems to have been nearly correspondent with the reign, in the vegetable kingdom, of the Acrogens and Gymnogens, with the intermediate cla.s.ses, their allies. At length, during the ages of the Chalk, the Cycloids and Ctenoids were ushered in, and were gradually developed in creation until the human period, in which they seem to have reached their culminating point, and now many times exceed in number and importance all other fishes. We do not see a sturgeon (our British representative of the ganoids) once in a twelvemonth; and though the skate and dog-fish (our representatives of the placoids) are greatly less rare, their number bears but a small proportion to that of the fishes belonging to the two prevailing orders, of which thousands of boat-loads are landed on our coasts every day.
The all but entire disappearance of the ganoids from creation is surely a curious and not unsuggestive circ.u.mstance. In the human family there are races that have long since reached their culminating point, and are now either fast disappearing or have already disappeared. The Aztecs of Central America, or the Copts of the valley of the Nile, are but the inconsiderable fragments of once mighty nations, memorials of whose greatness live in the vast sepulchral mounds of the far West, or in the temples of Thebes or Luxor, or the pyramids of Gizah. But in the rivers of these very countries,--in the Polypterus of the Nile, or the Lepidosteus of the Mississippi,--we are presented with the few surviving fragments of a dynasty compared with which that of Egypt or of Central America occupied but an exceedingly small portion of either s.p.a.ce or time. The dynasty of the ganoids was at one time coextensive with every river, lake, and sea, and endured during the unreckoned _eons_ which extended from the times of the Lower Old Red Sandstone until those of the Chalk. I may here mention, that as there are orders of plants, such as the Rosaceae and the Gra.s.ses, that scarce preceded man in their appearance, so there are families of fishes that seem peculiarly to belong to the human period. Of these, there is a family very familiar on our coasts, and which, though it furnishes none of our higher ichthyic luxuries, is remarkable for the numbers of the human family which it provides with a wholesome and palatable food. The delicate Salmonidae and the Pleuronectidae,--families to which the salmon and turbot belong,--were ushered into being as early as the times of the Chalk; but the Gadidae or cod family,--that family to which the cod proper, the haddock, the dorse, the whiting, the coal-fish, the pollock, the hake, the torsk, and the ling belong, with many other useful and wholesome species,--did not precede man by at least any period of time appreciable to the geologist. No trace of the family has yet been detected in even the Tertiary rocks.
[Ill.u.s.tration: Fig. 57
PTERICHTHYS OBLONGUS.
(One half nat. size.)]
Of the ganoids of the second age of vertebrate existence,--that of the Old Red Sandstone,--some were remarkable for the strangeness of their forms, and some for const.i.tuting links of connection which no longer exist in nature, between the ganoid and placoid orders. The Acanth family, which ceased with the Coal Measures, was characterized, especially in its Old Red species, by a combination of traits common to both orders; and among the extremer forms, in which Palaeontologists for a time failed to detect that of the fish at all, we reckon those of the genera Coccosteus, Pterichthys, and Cephalaspis. The more aberrant genera, however, even while they consisted each of several species, were comparatively short lived. The Coccosteus and Cephalaspis were restricted to but one formation apiece; while the Pterichthys, which appears for the first time in the lower deposits of the Old Red Sandstone, becomes extinct at its close. On the other hand, some of the genera that exemplified the general type of their cla.s.s were extremely long lived. The Celacanths were reproduced in many various species, from the times of the Lower Old Red Sandstone to those of the Chalk; and the Cestracions, which appear in the Upper Ludlow Rocks as the oldest of fishes, continue in at least one species to exist still. It would almost seem as if some such law influenced the destiny of genera in this ichthyic cla.s.s, as that which we find so often exemplified in our species. The dwarf, or giant, or deformed person, is seldom a long liver;--all the more remarkable instances of longevity have been furnished by individuals cast in the ordinary mould and proportions of the species. Not a few of these primordial ganoids wore, however, of the highest rank and standing ever exemplified by their cla.s.s; and we find Aga.s.siz boldly a.s.signing a reason for their superiority to their successors, important for the fact which it embodies, and worthy, as coming from him, of our most respectful attention. "It is plain," we find him saying, "that before the cla.s.s of reptiles was introduced upon our globe, the fishes, being then the only representatives of the type of vertebrata, were invested with the characters of a higher order, embodying, as it were, a prospective view of a higher development in another cla.s.s, which was introduced as a distinct type only at a later period; and from that time the reptilian character, which had been so prominent in the oldest fishes, was gradually reduced, till in more recent periods, and in the present creation, the fishes lost all this herpetological relationship, and were at last endowed with characters which contrast as much, when compared with those of reptiles, as they agreed closely in the beginning. Lepidosteus alone reminds us in our time of these old-fashioned characters of the cla.s.s of fishes as it was in former days."
[Ill.u.s.tration: Fig. 58
PLEURACANTHUS LaeVISSIMUS.
(_Coal Measures._)
(Half nat. size.)]
The ancient fishes seem to have received their fullest development during the Carboniferous period. Their number was very great: some of them attained to an enormous size, and, though the true reptile had already appeared, they continued to retain, till the close of the system, the high reptilian character and organization. Nothing, however, so impresses the observer as the formidable character of the offensive weapons with which they were furnished, and the amazing strength of their defensive armature. I need scarce say, that the Palaeontologist finds no trace in nature of that golden age of the world, of which the poets delighted to sing, when all creatures lived together in unbroken peace, and war and bloodshed were unknown. Ever since animal life began upon our planet, there existed, in all the departments of being, carnivorous cla.s.ses, who could not live but by the death of their neighbors, and who were armed, in consequence, for their destruction, like the butcher with his axe and knife, and the angler with his hook and spear. But there were certain periods in the history of the past, during which these weapons a.s.sumed a more formidable aspect than at others; and never were they more formidable than in the times of the Coal Measures. The teeth of the Rhizodus--a ganoidal fish of our coal fields--were more sharp and trenchant than those of the crocodile of the Nile, and in the larger specimens fully four times the bulk and size of the teeth of the hugest reptile of this species that now lives. The dorsal spine of its contemporary, the Gyracanthus, a great placoid, much exceeded in size that of any existing fish: it was a mighty spear head, ornately carved like that of a New Zealand chief, but in a style that, when he first saw a specimen in my collection, greatly excited the admiration of Mr. Ruskin. But one of the most remarkable weapons of the period was the sting of the Pleuracanthus, another great placoid of the age of gigantic fishes. It was sharp and polished as a stiletto, but, from its rounded form and dense structure, of great strength; and along two of its sides, from the taper point to within a few inches of the base, there ran a thickly-set row of barbs, hooked downwards, like the thorns that bristle on the young shoots of the wild rose, and which must have rendered it a weapon not merely of destruction, but also of torture. The defensive armor of the period, especially that of its ganoids, seems to have been us remarkable for its powers of resistance as the offensive must have been for their potency in the a.s.sault; and it seems probable that in the great strength of the bony and enamelled armature of this order of fishes we have the secret of the extremely formidable character of the teeth, spines, and stings that coexisted along with it.
[Ill.u.s.tration: Fig. 59.
CARCHARIAS PRODUCTUS.
Cutting Tooth. (_Miocene._)]
[Ill.u.s.tration: Fig. 60.
PLACODUS GIGAS.
Crushing Teeth. (_Trias._)]
Such of the fishes of the present time as live on crustacea and the sh.e.l.led molluscs,--such as the Wra.s.se or rock-fish family, and at least one of the Goby family, the sea-wolf,--have an apparatus of crushing teeth greatly more solid and strong than the teeth of such of their contemporaries as are either herbivorous or feed on the weaker families of their own cla.s.s. A similar remark applies to the ancient sharks, as contrasted with those of later times. So long as the strongly-armed ganoidal order prevailed in nature, the sharks were furnished with ma.s.sive crushing teeth; but when the ganoids waned in creation, and the soft-scaled cycloid and ctenoid orders took and amply filled the place which they had left vacant, the well known modern form of sharks" teeth was introduced,--a form much rather suited for cutting soft bodies than for crushing hard ones. In fine, the offensive weapons of the times of the Coal Measures seem very formidable, just as those personal weapons of the middle ages seem so that were borne at a time when every soldier took the field cased in armor of proof. The slim scimitar or slender rapier would have availed but little against ma.s.sive iron helmets or mail coats of tempered steel. And so the warriors of the period armed themselves with ponderous maces, battle-axes as ma.s.sive as hammers, and double-handed swords of great weight and strength.
Before pa.s.sing onwards to other and higher cla.s.ses and orders, as they occurred in creation, permit me to make the formidable armor of the earlier fishes, offensive and defensive, the subject of a single remark.
We are told by Goethe, in his autobiography, that he had attained his sixth year when the terrible earthquake at Lisbon took place,--"an event," he says, "which greatly disturbed" his "peace of mind for the first time." He could not reconcile a catastrophe so suddenly destructive to thousands, with the ideas which he had already formed for himself of a Providence all-powerful and all-benevolent. But he afterwards learned, he tells us, to recognize in such events the "_G.o.d of the Old Testament._" I know not in what spirit the remark was made; but this I know, that it is the G.o.d of the Old Testament whom we see exhibited in all nature and all providence; and that it is at once wisdom and duty in his rational creatures, however darkly they may perceive or imperfectly they may comprehend, to hold in implicit faith that the Adorable Monarch of all the past and of all the future is a King who "can do no wrong." This early exhibition of tooth, and spine, and sting,--of weapons constructed alike to cut and to pierce,--to unite two of the most indispensable requirements of the modern armorer,--a keen edge to a strong back,--nay, stranger still, the examples furnished in this primeval time, of weapons formed not only to kill, but also to torture,--must be altogether at variance with the preconceived opinions of those who hold that until man appeared in creation, and darkened its sympathetic face with the stain of moral guilt, the reign of violence and outrage did not begin, and that there was no death among the inferior creatures, and no suffering. But preconceived opinion, whether it hold fast, with Lactantius and the old Schoolmen, to the belief that there can be no antipodes, or a.s.sert, with Caccini and Bellarmine, that our globe hangs lazily in the midst of the heavens, while the sun moves round it, must yield ultimately to scientific truth. And it is a truth as certain as the existence of a southern hemisphere, or the motion of the earth round both its own axis and the great solar centre, that, untold ages ere man had sinned or suffered, the animal creation exhibited exactly its present state of war,--that the strong, armed with formidable weapons, exquisitely constructed to kill, preyed upon the weak; and that the weak, sheathed, many of them, in defensive armor equally admirable in its mechanism, and ever increasing and multiplying upon the earth far beyond the requirements of the mere maintenance of their races, were enabled to escape, as species, the a.s.saults of the tyrant tribes, and to exist unthinned for unreckoned ages. It has been weakly and impiously urged,--as if it were merely with the geologist that men had to settle this matter,--that such an economy of warfare and suffering,--of warring and of being warred upon,--would be, in the words of the infant Goethe, unworthy of an all-powerful and all-benevolent Providence, and in effect a libel on his government and character. But that grave charge we leave the objectors to settle with the great Creator himself. Be it theirs, not ours, according to the poet, to
"s.n.a.t.c.h from his hand the balance and the rod, Rejudge his justice, be the G.o.d of G.o.d."
Be it enough for the geologist rightly to interpret the record of creation,--to declare the truth as he finds it,--to demonstrate, from evidence no clear intellect ever yet resisted, that he, the Creator, from whom even the young lions seek their food, and who giveth to all the beasts, great and small, their meat in due season, ever wrought as he now works in his animal kingdom,--that he gave to the primeval fishes their spines and their stings,--to the primeval reptiles their trenchant teeth and their strong armor of bone,--to the primeval mammals their great tusks and their sharp claws,--that he of old divided all his creatures, as now, into animals of prey and the animals preyed upon,--that from the beginning of things he inseparably established among his non-responsible existences the twin laws of generation and of death,--nay, further, pa.s.sing from the established truths of _Geologic_ to one of the best established truths of _Theologic_ science,--G.o.d"s eternal justice and truth,--let us a.s.sert, that in the Divine government the matter of fact always determines the question of right, and that whatever has been done by him who rendereth no account to man of his matters, he had in all ages, and in all places, an unchallengeable right to do.
The oldest known reptiles appear just a little before the close of the Old Red Sandstone, just as the oldest known fishes appeared just a little before the close of the Silurian System. What seems to be the Upper Old Red of our own country, though there still hangs a shade of doubt on the subject, has furnished the remains of a small reptile, equally akin, it would appear, to the lizards and the batrachians; and what seems to be the Upper Old Red of the United States has exhibited the foot-tracks of a larger animal of the same cla.s.s, which not a little resemble those which would be impressed on recent sand or clay by the alligator of the Mississippi, did not the alligator of the Mississippi efface its own footprints (a consequence of the shortness of its legs) by the trail of its abdomen. In the Coal Measures, the reptiles. .h.i.therto found,--and it is still little more than ten years since the first was detected,--are all allied, though not without a cross of the higher crocodilian or lacertian nature, to the batrachian order,--that lowest order of the reptiles to which the frogs, newts, and salamanders belong.
These reptiles of the carboniferous era, though only a few twelvemonths ago we little suspected the fact, seem to have been not very rare in our own neighborhood. My attention was called some time since by Mr. Henry Cadell,--an intelligent practical geologist,--to certain appearances in one of the Duke of Buccleuch"s coal pits near Dalkeith, which lie regarded as the tracks of air-breathing quadrupeds; and, after examining a specimen, containing four footprints, which he had brought above ground, and which not a little excited my curiosity, we visited the pit together. And there, in a side working about half a mile from the pit mouth, and about four hundred feet under the surface, I found the roof of the coal, which rose at a high angle, traversed by so many foot-tracks, upwards, downwards, and athwart, that it cost me some little care to trace the individual lines. At least one of the number, however,--consisting of eleven footprints of the right and as many of the left foot--I was able to trace from side to side of the working, a distance of four yards; and several of the others for shorter s.p.a.ces.
The prints, which were reverses or casts in a very coa.r.s.e sandstone, were about thirtecn inches apart across the creature"s chest, and rather more than a foot apart from its fore to its hinder limbs. They were alternately larger and smaller,--the smaller (those of the fore feet) measuring about four inches in length, and the larger (those of the hinder feet) about six inches. The number of toes seemed to be alternately four and five; but from the circ.u.mstance that the original matrix on which the tracks had been impressed,--a micaceous clay resolved into a loose fissile sandstone,--had fallen away in the working of the pit, leaving but the boldly-relieved though ill-defined casts on the coa.r.s.e sandstone, I could not definitely determine the point.
Enough, however, remained to show that at that spot,--little more than a mile from where the Duke of Buccleuch"s palace now stands,--large reptiles had congregated in considerable numbers shortly after the great eight feet coal seam of the Dalkeith basin had been formed. In another part of the pit I found foot-tracks of apparently the same animal in equal abundance, but still less distinct in their state of keeping. But they bore testimony with the others to the comparative abundance of reptilian life at an early period, when the coal-bearing strata of the empire were little more than half deposited. It was not, however, until the Permian and Tria.s.sic Systems had come to a close, and even the earlier ages of the Oolitic System had pa.s.sed away, that the cla.s.s received its fullest development in creation. And certainly very wonderful was the development which it then did receive. Reptiles became everywhere the lords and masters of this lower world. When any cla.s.s of the air-breathing vertebrates is very largely developed, we find it taking possession of all the three old terrestrial elements,--earth, air, and water. The human period, for instance, like that which immediately preceded it, is peculiarly a period of mammals; and we find the cla.s.s, _free_, if I may so express myself, of the three elements, disputing possession of the sea with the fishes, in its Cetaceans, its seals, and its sea-lions, and of the air with the birds, in its numerous genera of the bat family. Further, not until the great mammaliferous period is fairly ushered in do either the bats or the whales make their appearance in creation. Remains of Oolitic reptiles have been mistaken in more than one instance for those of Cetacea; but it is now generally held that the earliest known specimens of the family belong to the Tertiary ages, while those of the oldest bats occur in the Eocene of the Paris Basin, a.s.sociated with the bones of dolphins, lamantines, and morses. Now, in the times of the Oolite it was the reptilian cla.s.s that possessed itself of all the elements. Its gigantic enaliosaurs, huge reptilian _whales_ mounted on paddles, were the tyrants of the ocean, and must have reigned supreme over the already reduced cla.s.s of fishes; its pterodactyles,--dragons as strange as were ever feigned by romancer of the middle ages, and that to the jaws and teeth of the crocodile added the wings of a bat and the body and tail of an ordinary mammal, had "the power of the air," and, pursuing the fleetest insects in their flight, captured and bore them down;[14] its lakes and rivers abounded in crocodiles and fresh water tortoises of ancient type and fashion; and its woods and plains were the haunts of a strange reptilian fauna, of what has been well termed "fearfully great lizards,"--some of which, such as the iguanodon, rivalled the largest elephant in height, and greatly more than rivalled him in length and bulk. Judging from what remains, it seems not improbable that the reptiles of this Oolitic period were quite as numerous individually, and consisted of well nigh as many genera and species, as all the mammals of the present time. In the cretaceous ages, the cla.s.s, though still the dominant one, is visibly reduced in its standing; it had reached its culminating point in the Oolite, and then began to decline; and with the first dawn of the Tertiary division we find it occupying, as now, a very subordinate place in creation. Curiously enough, it is not until its times of humiliation and decay that one of the most remarkable of its orders appears,--an order itself ill.u.s.trative of extreme degradation, and which figures largely, in every scheme of mythology that borrowed through traditional channels from Divine revelation, as a meet representative of man"s great enemy the Evil One. I of course refer to the ophidian or serpent family.
The earliest ophidian remains known to the Palaeontologist occur in that ancient deposit of the Tertiary division known as the London Clay, and must have belonged to serpents, some of them allied to the Pythons, some to the sea-snakes, which, judging from the corresponding parts of recent species, must have been from fourteen to twenty feet in length.
[Ill.u.s.tration: Fig. 61.
VESPERTILIO PARISIENSIS.
A Bat of the Eocene.]
[Ill.u.s.tration: Fig. 62
ICHTHYOSAURUS COMMUNIS.
(_Lias._)]
[Ill.u.s.tration: Fig. 63.
PLESIOSAURUS DOLICHODEIRUS.
(_Lias._)]
[Ill.u.s.tration: Fig. 64.
PTERODACTYLUS CRa.s.sIROSTRIS.
(_Oolite._)]
[Ill.u.s.tration: Fig. 65.
CHELONIA BENSTEDI.
(_Chalk._)]
[Ill.u.s.tration: Fig. 66.
PALaeOPHIS TOLIAPICUS.
(_Ophidian of the Eocene._)]
And here let us again pause for a moment, to remark how strangely these irascible, repulsive reptiles,--creatures lengthened out far beyond the proportions of the other members of their cla.s.s by mere vegetative repet.i.tions of the vertebrae,--condemned to derive, worm-like, their ability of progressive motion from the ring-like scutes of the abdomen--venomous in many of their species,--formidable in others to even the n.o.blest animals, from their fascinating powers and their great craft,--without, fore or hinder limbs, without thoracic or pelvic arches,--the very types and exemplars (our highest naturalists being the judges) of the extreme of animal degradation,--let us, I say, remark how strangely their history has been mixed up with that of man and of religion in all the older mythologies, and in that Divine Revelation whence the older mythologies were derived. It was one of the most ancient of the Phoenician fables, that the great antagonist of the G.o.ds was a gigantic serpent, that had at one time been their subject, but revolted against them and became their enemy. It was a monstrous serpent that a.s.sailed and strove to destroy the _mother_ of Apollo ere yet the birth of the G.o.d, but which, long after, _Apollo_ in turn a.s.saulted and slew. It was a great serpent that watched over the apples of the Hesperides, and that Hercules, ere he could possess himself of the fruit, had to combat and kill. It was a frightful serpent that guarded the golden fleece from Jason, and which the hero had to destroy in the first instance, and next to exterminate the strange brood of armed men that sprang up from its sown teeth. In short, the old mythologies are well nigh as full of the serpent as those ancient Runic obelisks of our country, whose endless knots and complicated fretwork are formed throughout of the interlacings of snakes. Let us, however, accept as representative of this innumerable cla.s.s of legends, the cla.s.sical story, rendered yet more cla.s.sical by the profound and reverend comment given by Bacon in his "Wisdom of the Ancients."
"Jupiter and the other G.o.ds," says the philosopher, in his simple version of the tradition, "conferred upon men a most acceptable and desirable boon,--the gift of perpetual youth. But men, foolishly overjoyed hereat, laid this present of the G.o.ds upon an a.s.s, who, in returning back with it, being extremely thirsty, and coming to a fountain, the serpent who was guardian thereof would not suffer him to drink but upon condition of receiving the burden he carried, whatever it should be. The silly a.s.s complied; and thus the perpetual renewal of youth was for a sup of water transferred from men to the race of serpents." "That this gift of perpetual youth should pa.s.s from men to serpents," continues Bacon, "seems added, by way of ornament and ill.u.s.tration, to the fable." And it certainly _has_ much the appearance of an after-thought. But how very striking the resemblance, borne by the story, as a whole, to that narrative in the opening page of human history which exhibits the first parents of the race as yielding up to the temptation of the serpent the gift of immortality; and further, how remarkable the fact, that the reptile selected as typical here of the great fallen spirit that kept not his first estate, should be at once the reptile of latest appearance in creation, and the one selected by philosophical naturalists as representative of a reversed process in the course of being,--of a downward, sinking career, from the vertebrate antetype towards greatly lower types in the invertebrate divisions! The fallen spirit is represented in revelation by what we are now taught to recognize in science as a _degraded_ reptile.