Engraved by J. Sartain.—From a original Talbotype.

Gould & Lincoln, Boston

THE
FOOT-PRINTS OF THE CREATOR:
OR,
THE ASTEROLEPIS OF STROMNESS.

BY
HUGH MILLER,
AUTHOR OF “THE OLD RED SANDSTONE,” ETC.

“When I asked him how this earth could have been repeopled if ever it had undergone the same fate it was threatened with by the comet of 1680, he answered,—‘that required the power of a Creator.’”—Conduit’s “Conversation with Sir Isaac Newton”.

FROM THE THIRD LONDON EDITION.

WITH A MEMOIR OF THE AUTHOR
BY LOUIS AGASSIZ.

BOSTON:
GOULD AND LINCOLN.
69 WASHINGTON STREET.
NEW YORK: SHELDON AND COMPANY.
CINCINNATI: GEO. S. BLANCHARD.
1868.

Entered according to Act of Congress, in the year 1850, by
Gould, Kendall and Lincoln,
In the Clerk’s Office of the District Court for the District of Massachusetts.

TO
SIR PHILIP DE MALPAS GREY EGERTON,
BART. M.P., F.R.S. & G.S.

To you, Sir, as our highest British authority on fossil fishes, I take the liberty of dedicating this little volume. In tracing the history of Creation, as illustrated in that ichthyic division of the vertebrata which is at once the most ancient and the most extensively preserved, I have introduced a considerable amount of fact and observation, for the general integrity of which my appeal must lie, not to the writings of my friends the geologists, but to the strangely significant record inscribed in the rocks, which it is their highest merit justly to interpret and faithfully to transcribe. The ingenious and popular author whose views on Creation I attempt controverting, virtually carries his appeal from science to the want of it. I would fain adopt an opposite course: And my use, on this occasion, of your name, may serve to evince the desire which I entertain that the collation of my transcripts of hitherto uncopied portions of the geologic history with the history itself, should be in the hands of men qualified, by original vigor of faculty and the patient research of years, either to detect the erroneous or to certify the true. Further, I feel peculiar pleasure in availing myself of the opportunity furnished me, by the publication of this little work, of giving expression to my sincere respect for one who, occupying a high place in society, and deriving his descent from names illustrious in history, has wisely taken up the true position of birth and rank in an enlightened country and age; and who, in asserting, by his modest, persevering labors, his proper standing in the scientific world, has rendered himself first among his countrymen in an interesting department of Natural Science, to which there is no aristocratic or “royal road.”

I have the honor to be, Sir,

With admiration and respect,

Your obedient humble servant,

HUGH MILLER.

TO THE READER.

There are chapters in this little volume which will, I am afraid, be deemed too prolix by the general reader, and which yet the geologist would like less were there any portion of them away. They refer chiefly to organisms not hitherto figured nor described, and must owe their modicum of value to that very minuteness of detail which, by critics of the merely literary type, unacquainted with fossils, and not greatly interested in them, may be regarded as a formidable defect, suited to overlay the general subject of the work. Perhaps the best mode of compromising the matter may be to intimate, as if by beacon, at the outset, the more repulsive chapters; somewhat in the way that the servants of the Humane Society indicate to the skater who frequents in winter the lakes in the neighborhood of Edinburgh, those parts of the ice on which he might be in danger of losing himself. I would recommend, then, readers not particularly palæontological, to pass but lightly over the whole of my fourth and fifth chapters, with the latter half of the third, marking, however, as they skim the pages, the conclusions at which I arrive regarding the bulk and organization of the extraordinary animal described, and the data on which these are founded. My book, like an Irish landscape dotted with green bogs, has its portions on which it may be perilous for the unpractised surveyor to make any considerable stand, but across which he may safely take his sights and lay down his angles.

It will, I trust, be found, that in dealing with errors which, in at least their primary bearing, affect questions of science, I have not offended against the courtesies of scientific controversy. True, they are errors which also involve moral consequences. There is a species of superstition which inclines men to take on trust whatever assumes the name of science; and which seems to be a reaction on the old superstition, that had faith in witches, but none in Sir Isaac Newton, and believed in ghosts, but failed to credit the Gregorian calendar. And, owing mainly to the wide diffusion of this credulous spirit of the modern type, as little disposed to examine what it receives as its ancient unreasoning predecessor, the development doctrines are doing much harm on both sides of the Atlantic, especially among intelligent mechanics, and a class of young men engaged in the subordinate departments of trade and the law. And the harm, thus considerable in amount, must be necessarily more than merely considerable in degree. For it invariably happens, that when persons in these walks become materialists, they become also turbulent subjects and bad men. That belief in the existence after death, which forms the distinguishing instinct of humanity, is too essential a part of man’s moral constitution not to be missed when away; and so, when once fairly eradicated, the life and conduct rarely fail to betray its absence. But I have not, from any consideration of the mischief thus effected, written as if arguments, like cannon-balls, could be rendered more formidable than in the cool state by being made red-hot. I have not even felt, in discussing the question, as if I had a man before me as an opponent; for though my work contains numerous references to the author of the “Vestiges,” I have invariably thought on these occasions, not of the anonymous writer of the volume, of whom I know nothing, but simply of an ingenious, well-written book, unfortunate in its facts and not always very happy in its reasonings. Further, I do not think that palæontological fact, in its bearing on the points at issue, is of such a doubtful complexion as to leave the geologist, however much from moral considerations in earnest in the matter, any very serious excuse for losing his temper.

In my reference to the three great divisions of the geologic scale, I designate as Palæozoic all the fossiliferous rocks, from the first appearance of organic existence down to the close of the Permian system; all as Secondary, from the close of the Permian system down to the close of the Cretaceous deposits; and all as Tertiary, from the close of the Cretaceous deposits down to the introduction of man. The wood-cuts of the volume, of which at least nine tenths of the whole represent objects never figured before, were drawn and cut by Mr. John Adams of Edinburgh, (8, Heriot Place,) with a degree of care and skill which has left me no reason to regret my distance from the London artists and engravers. So far at least as the objects could be adequately represented on wood, and in the limited space at Mr. Adams’ command, their truth is such that I can safely recommend them to the palæontologist. In the accompanying descriptions, and in my statements of geologic fact in general, it will, I hope, be seen that I have not exaggerated the peculiar features on which I have founded, nor rendered truth partial in order to make it serve a purpose. Where I have reasoned and inferred, the reader will of course be able to judge for himself whether the argument be sound or the deduction just; and to weigh, where I have merely speculated, the probability of the speculation; but as, in at least some of my statements of fact, he might lie more at my mercy, I have striven in every instance to make these adequately representative of the actualities to which they refer. And so, if it be ultimately found that on some occasions I have misled others, it will, I hope, be also seen to be only in cases in which I have been mistaken myself. The first or popular title of my work, “Foot-prints of the Creator,” I owe to Dr. Hetherington, the well-known historian of the Church of Scotland. My other various obligations to my friends, literary and scientific, the reader will find acknowledged in the body of the volume, as the occasion occurs of availing myself of either the information communicated, or the organism, recent or extinct, lent me or given.

HUGH MILLER,
AUTHOR OF
“OLD RED SANDSTONE” AND “FOOTPRINTS OF THE CREATOR.”

The geological works of Hugh Miller have excited the greatest interest, not only among scientific men, but also among general readers. There is in them a freshness of conception, a power of argumentation, a depth of thought, a purity of feelings, rarely met with in works of that character, which are well calculated to call forth sympathy, and to increase the popularity of a science which has already done so much to expand our views of the Plan of Creation. The scientific illustrations published by Mr. Miller are most happily combined with considerations of a higher order, rendering both equally acceptable to the thinking reader. But what is in a great degree peculiar to our author, is the successful combination of Christian doctrines with pure scientific truths. On that account, his works deserve peculiar attention. His generalizations have nothing of the vagueness which too often characterize the writings of those authors who have attempted to make the results of science subservient to the cause of religion. Struck with the beauty of Mr. Miller’s works, it has for some time past been my wish to see them more extensively circulated in this country; and I have obtained leave from the author to publish an American edition of his “Footprints of the Creator,” for which he has most liberally furnished the publishers with the admirable wood-cuts of the original.

While preparing some additional chapters, and various notes illustrative of certain points alluded to incidentally in this work, it was deemed advisable to preface it with a short biographical notice of the author. I had already sketched such a paper, when I became acquainted with a full memoir of this remarkable man, containing most interesting details of his earlier life, written by that eminent historian of the “Martyrs of Science,” the great natural philosopher of Scotland. It has occurred to me that, owing to the frequent references which I could not avoid to my own researches, I had better substitute this ample Biography for my short sketch, with such alterations and additions as the connection in which it is brought here would require. I therefore proceed to introduce our author with Sir David Brewster’s own words:—

Of all the studies which relate to the material universe, there is none, perhaps, which appeals so powerfully to our senses, or which comes into such close and immediate contact with our wants and enjoyments, as that of Geology. In our hourly walks, whether on business or for pleasure, we tread with heedless step upon the apparently uninteresting objects which it embraces: but could we rightly interrogate the rounded pebble at our feet, it would read us an exciting chapter on the history of primeval times, and would tell us of the convulsions by which it was wrenched from its parent rock, and of the floods by which it was abraded and transported to its present humble locality. In our visit to the picturesque and the sublime in nature, we are brought into closer proximity to the more interesting phenomena of geology. In the precipices which protect our rock-girt shores, which flank our mountain glens, or which variegate our lowland valleys, and in the shapeless fragments at their base, which the lichen colors, and round which the ivy twines, we see the remnants of uplifted and shattered beds, which once reposed in peace at the bottom of the ocean. Nor does the rounded boulder, which would have defied the lapidary’s wheel of the Giant Age, give forth a less oracular response from its grave of clay, or from its lair of sand. Floated by ice from some Alpine summit, or hurried along in torrents of mud, and floods of water, it may have traversed a quarter of the globe, amid the crash of falling forests, and the death shrieks of the noble animals which they sheltered. The mountain range, too, with its catacombs below, along which the earthquake transmits its terrific sounds, reminds us of the mighty power by which it was upheaved;—while the lofty peak, with its cap of ice, or its nostrils of fire, places in our view the tremendous agencies which have been at work beneath us.

But it is not merely amid the powers of external nature that the once hidden things of the Earth are presented to our view. Our temples and our palaces are formed from the rocks of a primeval age; bearing the very ripple-marks of a Pre-Adamite ocean,—grooved by the passage of the once moving boulder, and embosoming the relics of ancient life, and the plants by which it was sustained. Our dwellings, too, are ornamented with the variegated limestones,—the indurated tombs of molluscous life,—and our apartments heated with the carbon of primeval forests, and lighted with the gaseous element which it confines. The obelisk of granite, and the colossal bronze which transmit to future ages the deeds of the hero and the sage, are equally the production of the Earth’s prolific womb; and from the green bed of the ocean has been raised the pure and spotless marble, to mould the divine lineaments of beauty, and perpetuate the expressions of intellectual power. From a remoter age, and a still greater depth, the primary and secondary rocks have yielded a rich tribute to the chaplet of rank, and to the processes of art.

Exhibiting, as it peculiarly does, almost all those objects of interest and research, Scotland has been diligently studied both by native and foreign observers; and she has sent into the geological field a distinguished group of inquirers, who have performed a noble feat in exploring the general structure of the Earth, in decyphering its ancient monuments, and in unlocking those storehouses of mineral wealth, from which civilized man derives the elements of that gigantic power which his otherwise feeble arm wields over nature.

The occurrence of shells on the highest mountains, and the remains of plants and animals, which the most superficial observer could not fail to notice, in the rocks around him, have for centuries commanded the attention and exercised the ingenuity of every student of nature. But though sparks of geological truth were from time to time elicited by speculative minds, it was not till the end of the last century that its great lights broke forth, and that it took the form and character of one of the noblest of the sciences. Without undervaluing the labors of Werner, and other illustrious foreigners, or those of our southern countrymen, Mitchell and Smith, at the close of the last century, we may characterize the commencement of the present as the brightest period of geological discovery, and place its most active locality in the northern metropolis of our island. It was doubtless from the Royal Society of Edinburgh, as a centre, that a great geological impulse was propagated southward, and it was by the collision of the Wernerian and Huttonian views, the antagonist theories of water and of fire, that men of intellectual power were summoned from other studies; and that grand truths, which fanaticism and intolerance had hitherto abjured, rose triumphant over the ignorance and bigotry of the age. The Geological Society of London, which doubtless sprung from the excitement in the Scottish metropolis, entered on the new field of research with a faltering step. The prejudices of the English mind had been marshalled with illiberal violence against the Huttonian doctrines. Infidelity and Atheism were charged against their supporters; and had there been a Protestant Inquisition in England at that period of general political excitement, the geologists of the north would have been immured in its deepest dungeons.

Truth, however, marched apace; and though her simple but majestic procession be often solemn and slow, and her votaries few and dejected, yet on this, as on every occasion, she triumphed over the most inveterate prepossessions, and finally took up her abode in those very halls and institutions where she had been persecuted and reviled. When their science had been thus acquitted of the charge of impiety and irreligion, the members of the Geological Society left their humble and timid position of being the collectors only of the materials of future generalizations, and became at once the most successful observers of geological phenomena, and the boldest asserters of geological truth.

In this field of research, in which the physical, as well as the intellectual, frame of the philosopher is made tributary to science, two of our countrymen—Sir Roderick Murchison and Sir Charles Lyell—have been among our most active laborers. From the study of their native glens, these distinguished travellers, like the Humboldts and the Von Buchs of the continent, have passed into foreign lands, exploring the north and the south of Europe, and extending their labors to the eastern ranges of the Ural and the Timan, and to the Apallachians and the Alleghanies in the far west. But while our two countrymen were interrogating the strata of other lands, many able and active laborers had been at work in their own.

Among the eminent students of the structure of the earth, Mr. Hugh Miller holds a lofty place, not merely from the discovery of new and undescribed organisms in the Old Red Sandstone, but from the accuracy and beauty of his descriptions, the purity and elegance of his composition, and the high tone of philosophy and religion which distinguishes all his writings. Mr. Miller is one of the few individuals in the history of Scottish science who have raised themselves above the labors of an humble profession, by the force of their genius and the excellence of their character, to a comparatively high place in the social scale. Mr. Telford, like Mr. Miller, followed the profession of a stone-mason, before his industry and self-tuition qualified him for the higher functions of an architect and an engineer. And Mr. Watt and Mr. Rennie rose to wealth and fame without the aid of a university education. But, distinguished as these individuals were, none of them possessed those qualities of mind which Mr. Miller has exhibited in his writings; and, with the exception of Burns, the uneducated genius which has done honor to Scotland during the last century, has never displayed that mental refinement, and classical taste, and intellectual energy, which mark all the writings of our author. We wish that we could have gratified our readers with an authentic and even detailed narrative of the previous history of so remarkable a writer, and of the steps by which his knowledge was acquired, and the difficulties which he encountered in its pursuit; but though this is not, to any great extent, in our power, we shall at least be able, chiefly from Mr. Miller’s own writings, to follow him throughout his geological career.

Mr. Miller was born at Cromarty, of humble but respectable parents, whose history would have possessed no inconsiderable interest, even if it had not derived one of a higher kind from the genius and fortunes of their child. By the paternal side he was descended from a race of sea-faring people, whose family burying-ground, if we judge from the past, seems to be the sea. Under its green waves his father sleeps: his grandfather, his two granduncles, one of whom sailed round the world with Anson, lie also there; and the same extensive cemetery contains the relics of several of his more distant relatives. His father was but an infant of scarcely a year old, at the death of our author’s grandfather, and had to commence life as a poor ship-boy; but such was the energy of his mind, that, when little turned of thirty, he had become the master and owner of a fine large sloop, and had built himself a good house, which entitled his son to the franchise on the passing of the Reform Bill. Having unfortunately lost his sloop in a storm, he had to begin the world anew, and he soon became master and owner of another, and would have thriven, had he lived; but the hereditary fate was too strong for him, and when our author was a little boy of five summers, his father’s fine new sloop foundered at sea in a terrible tempest, and he and his crew were never more heard of. Mr. Miller had two sisters younger than himself, both of whom died ere they attained to womanhood. His mother experienced the usual difficulties which a widow has to encounter in the decent education of her family; but she struggled honestly and successfully, and ultimately found her reward in the character and fame of her son. It is from this excellent woman that Mr. Miller has inherited those sentiments and feelings which have given energy to his talents as the defender of revealed truth, and the champion of the Church of his fathers. She was the great granddaughter of a venerable man, still well known to tradition in the north of Scotland as Donald Roy of Nigg,—a sort of northern Peden, who is described in the history of our Church as the single individual who, at the age of eighty, when the presbytery of the district had assembled in the empty church for the purpose of inducting an obnoxious presentee, had the courage to protest against the intrusion, and to declare “that the blood of the people of Nigg would be required at their hands, if they settled a man to the walls of that church.” Tradition has represented him as a seer of visions, and a prophesier of prophecies; but whatever credit may be given to stories of this kind, which have been told also of Knox, Welsh, and Rutherford, this ancient champion of Non-Intrusion was a man of genuine piety, and the savor of his ennobling beliefs and his strict morals has survived in his family for generations. If the child of such parents did not receive the best education which his native town could afford, it was not their fault, nor that of his teacher. The fetters of a gymnasium are not easily worn by the adventurous youth who has sought and found his pleasures among the hills and on the waters. They chafe the young and active limb that has grown vigorous under the blue sky, and never known repose but at midnight. The young philosopher of Cromarty was a member of this restless community; and he had been the hero of adventures and accidents among rocks and woods, which are still remembered in his native town. The parish school was therefore not the scene of his enjoyments; and while he was a truant, and, with reverence be it spoken, a dunce, while under its jurisdiction, he was busy in the fields and on the sea-shore in collecting those stores of knowledge which he was born to dispense among his fellow-men. He escaped, however, from school, with the knowledge of reading, writing, and a little arithmetic, and with the credit of uniting a great memory with a little scholarship. Unlike his illustrious predecessor, Cuvier, he had studied Natural History in the fields and among the mountains ere he had sought for it in books; while the French philosopher had become a learned naturalist before he had even looked upon the world of Nature. This singular contrast is not difficult to explain. With a sickly constitution and a delicate frame, the youthful Cuvier wanted that physical activity which the observation of Nature demands. Our Scottish geologist, on the contrary, in vigorous health, and with an iron frame, rushed to the rocks and the sea-shore in search of the instruction which was not provided for him at school, and which he could find no books to supply.

After receiving this measure of education, Mr. Miller set out in February, 1821, with a heavy heart, as he himself confesses, “to make his first acquaintance with a life of labor and restraint:”—

“I was but a slim, loose-jointed boy at the time, fond of the pretty intangibilities of romance, and of dreaming when broad awake; and woful change! I was now going to work at what Burns has instanced in his ‘Twa Dogs’ as one of the most disagreeable of all employments—to work in a quarry. Bating the passing uneasiness occasioned by a few gloomy anticipations, the portion of my life which had already gone by had been happy beyond the common lot. I had been a wanderer among rocks and woods,—a reader of curious books, when I could get them,—a gleaner of old traditionary stories,—and now I was going to exchange all my day-dreams and all my amusements for the kind of life in which men toil every day that they may be enabled to eat, and eat every day that they may be enabled to toil. The quarry in which I wrought lay on the southern shore of a noble inland bay, or frith, rather, (the Bay of Cromarty,) with a little, clear stream on the one side, and a thick fir wood on the other. It had been opened in the Old Red Sandstone of the district, and was overtopped by a huge bank of diluvial clay, and which rose over it in some places to the height of nearly thirty feet.”—Old Red Sandstone, p. 4.

After removing the loose fragments below, picks and wedges and levers were applied in vain by our author and his brother workmen to tear up and remove the huge strata beneath. Blasting by gunpowder became necessary. A mass of the diluvial clay came tumbling down, “bearing with it two dead birds, that in a recent storm had crept into one of the deeper fissures, to die in the shelter.” While admiring the pretty cock goldfinch, and the light-blue and grayish-yellow woodpecker, and moralizing on their fate, the workmen were ordered to lay aside their tools, and thus ended the first day’s labor of our young geologist. The sun was then sinking behind the thick fir wood behind him, and the long dark shadows of the trees stretching to the shore. Notwithstanding his blistered hands, and the fatigue which blistered them, he found himself next morning as light of heart as his fellow-laborers, and able to enjoy the magnificent scenery around him, which he thus so beautifully describes:—

“There had been a smart frost during the night, and the rime lay white on the grass as we passed onwards through the fields; but the sun rose in a clear atmosphere, and the day mellowed as it advanced into one of those delightful days of early spring which give so pleasing an earnest of whatever is mild and genial in the better half of the year. All the workmen rested at midday, and I went to enjoy my half hour alone on a mossy knoll in the neighboring wood, which commands through the trees a wide prospect of the bay and the opposite shore. There was not a wrinkle on the water, nor a cloud in the sky; and the branches were as moveless in the calm as if they had been traced on canvas. From a wooded promontory that stretched half way across the frith, there ascended a thin column of smoke. It rose straight on the line of a plummet for more than a thousand yards; and then, as reaching a thinner stratum of air, spread out equally on every side, like the foliage of a stately tree. Ben Wevis rose to the west, white with the yet unwasted snows of winter, and as sharply defined in the clear atmosphere as if all its sunny slopes and blue retiring hollows had been chiselled in marble. A line of snow ran along the opposite hills; all above was white, and all below was purple.”—Old Red Sandstone, pp. 6, 7.

In raising from its bed the large mass of strata which the gunpowder had loosened, on the surface of the solid stone, our young quarrier descried the ridged and furrowed ripple marks which the tide leaves upon every sandy shore, and he wondered what had become of the waves that had thus fretted the solid rock, and of what element they had been composed. His admiration was equally excited by a circular depression in the sandstone, “broken and flawed in every direction, as if it had been the bottom of a pool recently dried up, which had shrunk and split in the hardening.” And before the day closed, a series of large stones had rolled down from the clay, “all rounded and water-worn, as if they had been tossed in the sea or the bed of a river for hundreds of years.” Was the clay which enclosed them created on the rock upon which it lay? No workman ever manufactures a half-worn article!—were the ejaculations of the geologist at his alphabet.

Our author and his companions were soon removed to an easier wrought quarry, and one more pregnant with interest, which had been opened “in a lofty wall of cliffs that overhangs the northern shore of the Moray Frith.” Here the geology of the district exhibited itself in section.

“We see in one place the primary rock, with its veins of granite and quartz,—its dizzy precipices of gneiss, and its huge masses of hornblende; we find the secondary rock in another, with its bed of sandstone and shale,—its spars, its clays, and its nodular limestones. We discover the still little known but highly interesting fossils of the Old Red Sandstone in one deposition; we find the beautifully preserved shells and lignites of the lias in another. There are the remains of two several creations at once before us. The shore, too, is heaped with rolled fragments of almost every variety of rock,—basalts, ironstones, hypersthenes, porphyries, bituminous shales, and micaceous schists. In short, the young geologist, had he all Europe before him, could hardly choose for himself a better field. I had, however, no one to tell me so at the time, for geology had not yet travelled so far north; and so, without guide or vocabulary, I had to grope my way as I best might, and find out all its wonders for myself. But so slow was the process, and so much was I a seeker in the dark, that the facts contained in these few sentences were the patient gatherings of years.”—Old Red Sandstone, pp. 9, 10.

In this rich field of inquiry, our author encountered, almost daily, new objects of wonder and instruction. In one nodular mass of limestone he found the beautiful ammonite, like one of the finely sculptured volutes of an Ionic capital. Within others, fish-scales and bivalve shells; and in the centre of another he detected a piece of decayed wood. Upon quitting the quarry for the building upon which the workmen were to be employed, the workmen received half a holiday, and our young philosopher devoted this valuable interval to search for certain curiously shaped stones, which one of the quarriers told him resembled the heads of boarding-pikes, and which, under the name of thunder-bolts, were held to be a sovereign remedy for cattle that had been bewitched. On the shore two miles off, where he expected these remarkable bodies, he found deposits quite different either from the sandstone cliffs or the primary rocks further to the west. They consisted of “thin strata of limestone, alternating with thicker beds of a black slaty substance,” which burned with a bright flame and a bituminous odor. Though only the eighth part of an inch thick, each layer contained thousands of fossils peculiar to the lias,—scallops and gryphites, ammonites, twigs and leaves of plants, cones of pine, pieces of charcoal, and scales of fishes,—the impressions being of a chalky whiteness, contrasting strikingly with their black bituminous lair. Among these fragments of animal and vegetable life, he at last detected his thunder-bolt in the form of a Belemnite, the remains of a kind of cuttle-fish long since extinct.

In the exercise of his profession, which “was a wandering one,” our author advanced steadily, though slowly and surely, in his geological acquirements.

“I remember,” says he, “passing direct on one occasion from the wild western coast of Ross-shire, where the Old Red Sandstone leans at a high angle against the prevailing quartz rock of the district, to where, on the southern skirts of Mid-Lothian, the mountain limestone rises amid the coal. I have resided one season on a raised beach on the Moray Frith. I have spent the season immediately following amid the ancient granites and contorted schists of the central Highlands. In the north, I have laid open by thousands the shells and lignites of the Oolite; in the south, I have disinterred from their matrices of stone or of shale the huge reeds and tree ferns of the carboniferous period.... In the north, there occurs a vast gap in the scale. The Lias leans unconformably against the Old Red Sandstone; there is no mountain limestone, no coal measures, none of the New Red Marls or Sandstones. There are at least three entire systems omitted. But the upper portion of the scale is well-nigh complete. In one locality we may pass from the Lower to the Upper Lias, in another from the Inferior to the Great Oolite, and onward to the Oxford Clay and the Coral Rag. We may explore in a third locality beds identical in their organisms with the Wealden of Sussex. In a fourth, we find the flints and fossils of the chalk. The lower part of the scale is also well-nigh complete. The Old Red Sandstone is amply developed in Moray, Caithness, and Ross, and the Grauwacke very extensively in Banffshire. But to acquaint one’s self with the three missing formations,—to complete one’s knowledge of the entire scale, by filling up the hiatus,—it is necessary to remove to the south. The geology of the Lothians is the geology of at least two thirds of the gap, and perhaps a little more;—the geology of Arran wants only a few of the upper beds of the New Red Sandstone to fill it entirely.”—Old Red Sandstone, pp. 13-17.

After having spent nearly fifteen years in the profession of a stone-mason, Mr. Miller was promoted to a position more suited to his genius. When a bank was established in his native town of Cromarty, he received the appointment of accountant, and he was thus employed, for five years, in keeping ledgers and discounting bills. When the contest in the Church of Scotland had come to a close, by the decision of the House of Lords in the Auchterurder Case, Mr. Miller’s celebrated letter to Lord Brougham attracted the particular attention of the party which was about to leave the Establishment, and he was selected as the most competent person to conduct the Witness newspaper, the principal metropolitan organ of the Free Church. The great success which this journal has met with is owing, doubtless, to the fine articles, political, ecclesiastical, and geological, which Mr. Miller has written for it. In the few leisure hours which so engrossing an occupation has allowed him to enjoy, he has devoted himself to the ardent prosecution of scientific inquiries; and we trust the time is not far distant when the liberality of his country, to which he has done so much honor, will allow him to give his whole time to the prosecution of science.

Geologists of high character had believed that the Old Red Sandstone was defective in organic remains; and it was not till after ten years’ acquaintance with it that Mr. Miller discovered it to be richly fossiliferous. The labors of other ten years were required to assign to its fossils their exact place in the scale.

Among the fossils discovered by our author, the Pterichthys or winged fish is doubtless the most remarkable. He had disinterred it so early as 1831, but it was only in 1838 that he “introduced it to the acquaintance of geologists.” It was not till 1831 that Mr. Miller began to receive assistance in his studies from without. In the appendix to Messrs. Anderson of Inverness’s admirable Guide to the Highlands and Islands of Scotland, which “he perused with intense interest,” he found the most important information respecting the geology of the North of Scotland; and during a correspondence with the accomplished authors of that work, many of his views were developed, and his difficulties removed. In 1838, he communicated to Dr. Malcolmson of Madras, then in Paris, a drawing and description of the Pterichthys. His letter was submitted to Agassiz, and subsequently a restored drawing was communicated to the Elgin Scientific Society. The great naturalist, as well as the members of the provincial society, were surprised at the new form of life which Mr. Miller had disclosed, and some of them, no doubt, regarded it with a sceptical eye. “Not many months after, however, a true bona fide Pterichthys was turned up in one of the newly-discovered beds of Nairnshire.” In his last visit to Scotland, Agassiz found six species of the Pterichthys, three of which, and the wings of a fourth, were in Mr. Miller’s collection.

This remarkable animal has less resemblance than any other fossil of the Old Red Sandstone to anything that now exists. When first brought to view by the single blow of a hammer, there appeared on a ground of light-colored limestone the effigy of a creature, fashioned apparently out of jet, with a body covered with plates, two powerful looking arms articulated at the shoulders, a head as entirely lost in the trunk as that of the ray, (or skate,) and a long angular tail, equal in length to a third of the entire figure. Its general resemblance is to the letter T,—the upper part of the vertical line being swelled out, and the lower part ending in an angular point, the two horizontal portions being, in the opinion of Agassiz, organs of locomotion. To this remarkable fossil M. Agassiz has given the appropriate name of Pterichthys Milleri. An account of it, accompanied with two fine specimens, was communicated to the Geological Section of the British Association at Glasgow, in September, 1840; and the most ample details, with accurate drawings, were afterwards published, in 1841, in Mr. Miller’s first work, The Old Red Sandstone, which was dedicated to Sir Roderick Murchison, who was born on the Old Red Sandstone of the North, in the same district as Mr. Miller, and whose great acquirements and distinguished labors are known all over the world among scientific men. This admirable work has already passed through three editions. From the originality and accuracy of its descriptions, and the importance of the researches which it contains, it has obtained for its author a high reputation among geologists; while from the elegance and purity of its style, and the force and liveliness of its illustrations, it has received the highest praise from its more general readers.[1]

Although we have been obliged, from the information which it contains of our author’s early studies, to mention the “Old Red Sandstone” as if it had been his first work; yet so early as 1830, after he had made his first fossil discoveries at Cromarty, he composed a paper on the subject, (his first published production,) which appeared as one of the chapters of a small legendary and descriptive work, entitled The Traditional History of Cromarty, which did not appear till 1835. This chapter, entitled “The Antiquary of the World,” possesses a high degree of interest. After describing the scene around him in its pictorial aspect, and under the warm associations, which link it with existing life, he surveys it with the cool eye of an “antiquary of the world,” studying its once buried monuments, and decyphering the alphabet of plants and animals, the hieroglyphics which embosom the history of past times and of successive creations. The gigantic Ben Wevis, with its attendant hills, rose abruptly to the west. The distant peaks of Ben Vaichard appeared in the south, and far to the north were descried the lofty hills of Sutherland, and even the Ord-hill of Caithness. Descending from the towers of nature’s lofty edifice he surveys its ruins, its broken sculptures, and its half-defaced inscriptions, as exhibited in certain Ichthyic remains of the Lower Old Red Sandstone which had then no name, and which were unknown to the most accomplished geologists. Among these he specially notices “a confused bituminous-looking mass that had much the appearance of a toad or frog,” thus shadowing forth in the morning twilight the curious Pterichthys, which he was able afterwards, in better specimens, to exhibit in open day. As we have already referred, with some minuteness, to the fossils which our author had at this time discovered in the great charnel-house of the old world, we shall indulge our readers with a specimen of the noble sentiments which they inspired, and of the beautiful language in which these sentiments are clothed.

“But let us quit this wonderful city of the dead, with all its reclining obelisks, and all its sculptured tumuli, the memorials of a race that exist only in their tombs. And yet, ere we go, it were well, perhaps, to indulge in some of those serious thoughts which we so naturally associate with the solitary burying-ground and the mutilated remains of the departed. Let us once more look around us, and say, whether, of all men, the Geologist does not stand most in need of the Bible, however much he may contemn it in the pride of speculation. We tread on the remains of organized and sentient creatures, which, though more numerous at one period than the whole family of man, have long since ceased to exist; the individuals perished one after one—their remains served only to elevate the floor on which their descendants pursued the various instincts of their nature, and then sunk, like the others, to form a still higher layer of soil; and now that the whole race has passed from the earth, and we see the animals of a different tribe occupying their places, what survives of them but a mass of inert and senseless matter, never again to be animated by the mysterious spirit of vitality—that spirit which, dissipated in the air, or diffused in the ocean, can, like the sweet sounds and pleasant odors of the past, be neither gathered up nor recalled! And O, how dark the analogy which would lead us to anticipate a similar fate for ourselves! As individuals, we are but as yesterday; to-morrow we shall be laid in our graves, and the tread of the coming generation shall be over our heads. Nay, have we not seen a terrible disease sweep away, in a few years, more than eighty millions of the race to which we belong; and can we think of this and say that a time may not come when, like the fossils of these beds our whole species shall be mingled with the soil, and when, though the sun may look down in his strength on our pleasant dwellings and our green fields, there shall be silence in all our borders, and desolation in all our gates, and we shall have no thought of that past which it is now our delight to recall, and no portion in that future which it is now our very nature to anticipate. Surely it is well to believe that a widely different destiny awaits us—that the God who endowed us with those wonderful powers, which enable us to live in every departed era, every coming period, has given us to possess these powers forever; that not only does he number the hairs of our heads, but that his cares are extended to even our very remains; that our very bones, instead of being left, like the exuviæ around us, to form the rocks and clays of a future world, shall, like those in the valley of vision, be again clothed with muscle and sinew, and that our bodies, animated by the warmth and vigor of life, shall again connect our souls to the matter existing around us, and be obedient to every impulse of the will. It is surely no time, when we walk amid the dark cemeteries of a departed world, and see the cold blank shadows of the tombs falling drearily athwart the way—it is surely no time to extinguish the light given us to shine so fully and so cheerfully on our own proper path, merely because its beams do not enlighten the recesses that yawn around us. And O, what more unworthy of reasonable men than to reject so consoling a revelation on no juster quarrel, than when it unveils to us much of what could not otherwise be known, and without the knowledge of which we could not be other than unhappy, it leaves to the invigorating exercises of our own powers whatever, in the wide circle of creation, lies fully within their grasp!”—The Antiquary of the World, pp. 56-58.

The next work published by Mr. Miller was entitled “First Impressions of England and its People,”[2] a popular and interesting volume, which has already gone through two editions, and which may be read with equal interest by the geologist, the philanthropist, and the general reader. It is full of knowledge and of anecdote, and is written in that attractive style which commands the attention even of the most incurious readers.

This delightful work, though only in one volume, is equal to three of the ordinary type, and cannot fail to be perused with high gratification by all classes of readers. It treats of every subject which is presented to the notice of an accomplished traveller while he visits the great cities and romantic localities of merry England. We know of no tour in England written by a native in which so much pleasant reading and substantial instruction are combined; and though we are occasionally stopped in a very delightful locality by a precipice of the Old Red Sandstone, or frightened by a disinterred skeleton, or sobered by the burial-service over Palæozoic graves, we soon recover our equanimity, and again enter upon the sunny path to which our author never fails to restore us.

Mr. Miller’s new work, the “Footprints of the Creator,” of which we publish now another edition, authorized by the writer, is very appropriately dedicated to Sir Philip Grey Egerton, Bart., M. P. for Cheshire—a gentleman who possesses a magnificent collection of fossils, and whose skill and acquirements in this department of geology is known and appreciated both in Europe and America. The work itself is divided into fifteen chapters, in which the author treats of the fossil geology of the Orkneys, as exhibited in the vicinity of Stromness; of the development hypothesis, and its consequences; of the history and structure of that remarkable fish, the Asterolepis; of the fishes of the Upper and Lower Silurian rocks; of the progress of degradation, and its history; of the Lamarckian hypothesis of the origin of plants, and its consequences; of the Marine and Terrestrial floras; and of final causes, and their bearing on geological history. In the course of these chapters Mr. Miller discusses the development hypothesis, or the hypothesis of natural law, as maintained by Lamarck and by the author of the Vestiges of Creation, and has subjected it, in its geological aspect, to the most rigorous examination. Driven by the discoveries of Lord Rosse from the domains of astronomy, where it once seemed to hold a plausible position, it might have lingered with the appearance of life among the ambiguities of the Palæozoic formations; but Mr. Miller has, with an ingenuity and patience worthy of a better subject, stripped it even of its semblance of truth, and restored to the Creator, as Governor of the universe, that power and those functions which he was supposed to have resigned at its birth.

Having imposed upon himself the task of examining in detail the various fossiliferous formations of Scotland, our author extended his inquiries into the mainland of Orkney, and resided for some time in the vicinity of the busy seaport town of Stromness, as a central point from which the structure of the Orkney group of islands could be most advantageously studied. Like that of Caithness, the geology of these islands owes its principal interest to the immense development of the Lower Old Red Sandstone formation, and to the singular abundance of its vertebrate fossils. Though the Orkneys contain only the third part of the Old Red Sandstone, which, but a few years ago, was supposed to be the least productive in fossils of any of the geological formations, yet it furnishes, according to Mr. Miller, more fossil fish than every other geological system in England, Scotland, and Wales, from the Coal Measures to the Chalk, inclusive. It is, in short, “the land of fish,” and “could supply with ichthyolites, by the ton and by the ship-load, the museums of the world.” Its various deposits, with the curious organisms which they inclose, have been upheaved from their original position against a granitic axis, about six miles long and one broad, “forming the great back-bone of the western district of the Island Pomona; and on this granitic axis, fast jambed in between a steep hill and the sea, stands the town of Stromness.”

The mass or pile of strata thus uplifted is described by Mr. Miller as a three-barred pyramid resting on its granite base, exhibiting three broad tiers—red, black, and gray—sculptured with the hieroglyphics in which its history is recorded. The great conglomerate base on which it rests, covering from 10,000 to 15,000 square miles, from the depth of from 100 to 400 feet, consists of rough sand and water-worn pebbles; and above this have been deposited successive strata of mud, equal in height to the highest of our mountains, now containing the remains of millions and tens of millions of fish which had perished in some sudden and mysterious catastrophe.

In the examination of the different beds of the three-barred formation, our author discovered a well-marked bone, like a petrified large roofing nail, in a grayish-colored layer of hard flag, about 100 yards over the granite, and about 160 feet over the upper stratum of the conglomerate. This singular bone, which Mr. Miller has represented in a figure, was probably the oldest vertebrate organism yet discovered in Orkney. It was 5⅞ inches long, 2¼ inches across the head, and ³⁄₁₀ths of an inch thick in the stem, and formed a characteristic feature of the Asterolepis, as yet the most gigantic of the ganoid fishes, and probably one of the first of the Old Red Sandstone. In his former researches, our author had found that all of the many hundred ichthyolites which he had disinterred from the Lower Old Red Sandstone were comparatively of a small size, while those in the Upper Old Red were of great bulk; and hence he had naturally inferred, that vertebrate life had increased towards the close of the system—that, in short, it began with an age of dwarfs, and ended with an age of giants; but he had thus greatly erred, like the supporters of the development system, in founding positive conclusions on merely negative evidence; for here, at the very base of the system, where no dwarfs were to be found, he had discovered one of the most colossal of its giants.

After this most important discovery, Mr. Miller extended his inquiries easterly for several miles along the bare and unwooded Lake of Stennis, about fourteen miles in circumference, and divided into an upper arm lower sheet of water by two long promontories jutting out from each side and nearly meeting in the middle. The sea enters this lake through the openings of a long rustic bridge, and hence the lower division of the lake “is salt in its nether reaches, and brackish in its upper ones; while the higher division is merely brackish in its nether reaches, and fresh enough in its upper ones to be potable.” The fauna and flora of the lake are therefore of a mixed character, the marine and fresh water animals having each their own reaches, though each kind makes certain encroachments on the province of the other.

In the marine and lacustrine floras of the lake, Mr. Miller observed changes still more palpable. At the entrance of the sea, the Fucus nodosus and Fucus vesiculosus flourish in their proper form and magnitude. A little farther on in the lake, the F. nodosus disappears, and the F. vesiculosus, though continuing to exist for mile after mile, grows dwarfish and stunted, and finally disappears, giving place to rushes and other aquatic grasses, till the lacustrine has entirely displaced the marine flora. From these two important facts, the existence of the fragment of Asterolepis in the lower flagstones of the Orkneys, and of the “curiously mixed semi-marine semi-lacustrine vegetation in the Loch of Stennis,” which our author regards as bearing directly on the development hypothesis, he takes occasion to submit that hypothesis to a severe examination, and to point out its consequences—its incompatibility with the great truths of morality and revealed religion. According to Professor Oken, one of the ablest supporters of the development theory, “There are two kinds of generation in the world, the creation proper, and the propagation that is sequent thereon, or the original and secondary generation. Consequently, no organism has been created of larger size than an infusorial point. No organism is, or ever has been created, which is not microscopic. Whatever is large has not been created, but developed. Man has not been created, but developed.” Hence it follows that during the great geological period, when race after race was destroyed, and new forms of life called into being, “nature had been pregnant with the human race,” and that immortal and intellectual Man is but the development of the Brute—itself the development of some monad or mollusc, which has been smitten into life by the action of electricity upon a portion of gelatinous matter.

If the development theory be true, “the early fossils ought to be very small in size,” and “very low in organization.” In the earliest strata we ought to find only “mere embryos and fœtuses; and if we find instead the full-grown and mature, then must we hold that the testimony of geology is not only not in accordance with the theory, but in positive opposition to it.” Having laid this down as the principle by which the question is to be decided, our author proceeds to consider “what are the facts.” The Asterolepis of Stromness seems to be the oldest organism yet discovered in the most ancient geological system of Scotland, in which vertebrate remains occur. It is probably the oldest Cœlacanth that the world has yet produced, for there is no certain trace of this family in the great Silurian system, which lies underneath, and on which, according to our existing knowledge, organic existence first began. “How, then,” asks Mr. Miller, “on the two relevant points—bulk and organization—does it answer to the demands of the development hypothesis? Was it a mere fœtus of the finny tribe, of minute size and imperfect embryonic faculty? Or was it of, at least, the ordinary bulk, and, for its class, of the average organization?”

In order to answer these questions, Mr. Miller proceeds in his third chapter to give the recent history of the Asterolepis; in his fourth, to ascertain the cerebral development of the earlier vertebrata; and in his fifth chapter to describe the structure, bulk, and aspect of the Asterolepis. In the rocks of Russia certain fossil remains had been long ago discovered, of such a singular nature as to have perplexed Lamarck and other naturalists. Their true place among fishes was subsequently ascertained by M. Eichwald, a living naturalist; and Sir Roderick Murchison found that they were Ichthyolites of the Old Red Sandstone. Agassiz gave them the name of Chelonichthys; but in consequence of very fine specimens having been found in the Old Red Sandstone of Russia, which Professor Asmus of Dorpat sent to the British Museum, and which exhibited star-like markings, he abandoned his name of Chelonichthys, and adopted that of Asterolepis, or star-scale, which Eichwald had proposed. Many points, however, respecting this curious fossil remained to be determined, and it was fortunate for science that Mr. Miller was enabled to accomplish this object by means of a variety of excellent specimens which he received from Mr. Robert Dick, “an intelligent tradesman of Thurso, one of those working men of Scotland, of active curiosity and well developed intellect, that give character and standing to the rest.” Agassiz had inferred, from very imperfect fragments, that the Asterolepis was a strongly-helmed fish of the Cœlacanths, or hollow spine family—that it was probably a flat-headed animal, and that the discovery of a head or of a jaw might prove that the genus Dendrodus did not differ from it. All these conjectures were completely confirmed by Mr. Miller, after a careful examination of the specimens of Mr. Dick.

Before proceeding to describe the structure of the gigantic Asterolepis, Mr. Miller devotes a long and elaborate chapter to the subject of the cerebral development of the earlier vertebrata, in order to ascertain in what manner their true brains were lodged, and to discover the modification which the cranium, as their protecting box, received in subsequent periods. This inquiry, which he has conducted with great skill and ability, is not only highly interesting in itself, but will be found to have a direct bearing on the great question which it is his object to discuss and decide.

The facts and reasonings contained in this chapter will, we doubt not, shake to its very base the bold theory of Professor Oken, which has been so generally received abroad, and which is beginning to find supporters even among the solid thinkers of our own country. In the Isis of 1818, Professor Lorenz Oken has given the following account of the hypothesis to which we allude. “In August, 1806,” says he, “I made a journey over the Hartz. I slid down through the wood on the south side, and straight before me, at my very feet, lay a most beautiful blanched skull of a hind. I picked it up, turned it round, regarded it intensely;—the thing was done. ‘It is a vertebral column,’ struck me like a flood of lightning, ‘to the marrow and bone;’ and since that time the skull has been regarded as a vertebral column.”

This remarkable hypothesis was at first received with enthusiasm by the naturalists of Germany, and, among others, by Agassiz, who, from grounds not of a geological kind, has more recently rejected it. It has been adopted by our distinguished countryman, Professor Owen, and forms the central idea in his lately published and ingenious work “On the Nature of Limbs.” The conclusion at which he arrives, that the fore-limbs of the vertebrata are the ribs of the occipital bone or vertebra set free, and (in all the vertebrata higher in the scale than the ordinary fishes) carried down along the vertebral column by a sort of natural dislocation, is a deduction from the idea that startled Professor Oken in the forest of the Hartz. Whatever support this hypothesis might have expected from Geology, has been struck from beneath it by this remarkable chapter of Mr. Miller’s work; and though anatomists may for a while maintain it under the influence of so high an authority as Professor Owen, we are much mistaken if it ever forms a part of the creed of the geologist. Mr. Miller indeed has, by a most skilful examination of the heads of the earliest vertebrata known to geologists, proved that the hypothesis derives no support from the structure which they exhibit, and Agassiz has even upon general principles rejected it as untenable.

Mr. Miller’s next chapter on the structure, bulk, and aspect of the Asterolepis, is, like that which precedes it, the work of a master, evincing the highest powers of observation and analysis. Its size in the larger specimens must have been very great; and from a comparison of the proportion of the head in the Ganoids to the length of the body, which is sometimes as one to five, or one to six, or one to six and a half, or even one to seven, our author concludes that the total length of the specimens in his possession must have been at least eight feet three inches, or from nine feet nine to nine feet ten inches. The remains of an Asterolepis found by Mr. Dick at Thurso, indicate a length of from twelve feet five to thirteen feet eight inches; and one of the Russian specimens of Professor Asmus must have been from eighteen to twenty-three feet long. “Hence,” says Mr. Miller, “in the not unimportant circumstance of size—the most ancient Cœlacanths yet known, instead of taking their places agreeably to the demands of the development hypothesis among the sprats, sticklebacks, and minnows of their class, took their place among its huge basking sharks, gigantic sturgeons, and bulky swordfishes. They were giants, not dwarfs.” Again, judging by the analogies which its structure exhibits to that of fishes of the existing period, the Asterolepis must have been a fish high in the scale of organization.

A specimen of Asterolepis, discovered by Mr. Dick, among the Thurso rocks, and sent to Mr. Miller, exhibited the singular phenomenon of a quantity of thick tar lying beneath it, which stuck to the fingers when lifting the pieces of rock. “What had been once the nerves, muscles, and blood of this ancient Ganoid, still lay under its bones,” a phenomenon which our author had previously seen beneath the body of a poor suicide, whose grave in a sandy bank had been laid open by the encroachments of a river, the sand beneath it having been “consolidated into a dark colored pitchy mass,” extending a full yard beneath the body. In like manner, the animal juices of the Asterolepis had preserved its remains, by “the pervading bitumen, greatly more conservative in its effects than the oil and gum of an old Egyptian undertaker.” The bones, though black as pitch retained to a considerable degree the peculiar qualities of the original substance, in the same manner as the adipocire of wet burying-grounds preserves fresh and green the bones which it encloses.

In support of his anti-development views, Mr. Miller devotes his next and sixth chapter to the recent history, order, and size of the fishes of the Upper and Lower Silurian rocks. Of these ancient formations, the bone bed of the Upper Ludlow rocks is the only one which, besides defensive spines of fish, contains teeth, fragments of jaws, and shagreen points, whereas, in the inferior deposits, defensive spates alone are found. The species discovered by Professor Phillips, in the Wenlock shale, were microscopic; and the author of the Vestiges took advantage of this insulated fact to support his views, by pronouncing the little creatures to which the species belonged as the fœtal embryos of their class. Mr. Miller has, however, even on this ground, defeated his opponent. By comparing the defensive spines of the Onchus Murchisoni of the Upper Ludlow bed with those of a recent Spinax Acanthias, or dog-fish, and of the Cestracion Phillippi, or Port Jackson shark, he arrives at the conclusion, that the fishes to which the species belonged must be all of considerable size; and in the following chapter on the high standing of the Placoids he shews that the same early fishes were high in intelligence and organization.

In his ninth chapter on the History and Progress of Degradation, our author enters upon a new and interesting subject. The object of it is to determine the proper ground on which the standing of the earlier vertebrata should be decided, namely, the test of what he terms homological symmetry of organization. In nature there are monster families, just as there are in families monster individuals—men without feet, hands, or eyes, or with them in a wrong place—sheep with legs growing from their necks, ducklings with wings on their haunches, and dogs and cats with more legs than they require. We have thus, according to our author—1, monstrosity through defect of parts; 2, monstrosity through redundancy of parts; and 3, monstrosity through displacement of parts. This last species, united in some cases with the other two, our author finds curiously exemplified in the geological history of the fish, which he considers better known than that of any other division of the vertebrata; and he is convinced that it is from a survey of the progress of degradation in the great Ichthyic division that the standing of the kingly fishes of the earlier periods is to be determined.

In the earliest vertebrate period, namely, the Silurian, our author shews that the fishes were homologically symmetrical in their organization, as exhibited in the Placoids. In the second great Ichthyic period, that of the Old Red Sandstone, he finds the first example in the class of fishes of monstrosity, by displacement of parts. In all the Ganoids of the period, there is the same departure from symmetry as would take place in man if his neck was annihilated, and the arms stuck to the back of the head. In the Coccosteus and Pterichthys of the same period, he finds the first example of degradation through defect, the former resembling a human monster without hands, and the latter one without feet. After ages and centuries have passed away, and then after the termination of the Palæozoic period, a change takes place in the formation of the fish tail. “Other ages and centuries pass away, during which the reptile class attains to its fullest development in point of size, organization, and number; and then, after the times of the cretaceous deposits have begun, we find yet another remarkable monstrosity of displacement introduced among all the fishes of one very numerous order, and among no inconsiderable proportion of the fishes of another. In the newly-introduced Ctenoids (Acanthopterygii,) and in those families of the Cycloids which Cuvier erected into the order Malacopterygii sub-brachiati, the hinder limbs are brought forward and stuck on to the base of the previously misplaced fore limbs. All the four limbs, by a strange monstrosity of displacement, are crowded into the place of the extinguished neck. And such, in the present day, is the prevalent type among fishes. Monstrosity through defect is also found to increase; so that the snake-like apoda, or feet-wanting fishes, form a numerous order, some of whose genera are devoid, as in the common eels and the congers, of only the hinder limbs, while in others, as in the genera Muræna and Synbranchus, both hinder and fore-limbs are wanting.” From these and other facts, our author concludes that as in existing fishes we find many more proofs of the monstrosity, both from displacement and defect of parts, than in all the other three classes of the vertebrata, and as these monstrosities did not appear early, but late, “the progress of the race as a whole, though it still retains not a few of the higher forms, has been a progress not of development from the low to the high, but of degradation from the high to the low.” An extreme example of the degradation of distortion, superadded to that of displacement, may be seen in the flounder, plaice, halibut, or turbot,—fishes of a family of which there is no trace in the earlier periods. The creature is twisted half round and laid on its side. The tail, too, is horizontal. Half the features of its head are twisted to one side, and the other half to the other, while its wry mouth is in keeping with its squint eyes. One jaw is straight, and the other like a bow; and while one contains from four to six teeth, the other contains from thirty to thirty-five.

Aided by facts like these, an ingenious theorist might, as our author remarks, “get up as unexceptionable a theory of degradation as of development.” But however this may be, the principle of degradation actually exists, and “the history of its progress in creation bears directly against the assumption that the earlier vertebrata were of a lower type than the vertebrata of the same Ichthyic class which exist now.”

In his next and tenth chapter, our author controverts with his usual power the argument in favor of the development hypothesis, drawn from the predominance of the Brachiopods among the Silurian Molluscs. The existence of the highly organized Cephalopods, in the same formation, not only neutralizes this argument, but authorizes the conclusion that an animal of a very high order of organization existed in the earliest formation. It is of no consequence whether the Cephalopods, or the Brachiopods were most numerous. Had there been only one cuttle fish in the Silurian seas, and a million of Brachiopods, the fact would equally have overturned the development system.

In the same chapter, Mr. Miller treats of the geological history of the Fossil flora, which has been pressed into the service of the development hypothesis. On the authority of Adolphe Brongniart, it was maintained that, previous to the age of the Lias, “Nature had failed to achieve a tree—and that the rich vegetation of the Coal Measures had been exclusively composed of magnificent immaturities of the vegetable kingdom, of gigantic ferns and club mosses, that attained to the size of forest trees, and of thickets of the swamp-loving horse-tail family of plants.” True exogenous trees, however, do exist of vast size, and in great numbers, in all the coal-fields of our own country, as has been proved by Mr. Miller. Nay, he himself discovered in the Old Red Sandstone, Lignite, which is proved to have formed part of a true gymnospermous tree, represented by the pines of Europe and America, or more probably, as Mr. Miller believes, by the Araucarians of Chili and New Zealand. This important discovery is pregnant with instruction. The ancient Conifer must have waved its green foliage over dry land, and it is not probable that it was the only tree in the primeval forest. “The ship carpenter,” as our author observes, “might have hopefully taken axe in hand to explore the woods for some such stately pine as the one described by Milton,—

‘Hewn on Norwegian hills, to be the mast

Of some great admiral.’”

Viewing this olive leaf of the Old Red Sandstone as not at all devoid of poetry, our author invites us to a voyage from the latest formation up to the first zone of the Silurian formation,—thus passing from ancient to still more ancient scenes of being, and finding, as at the commencement of our voyage, a graceful intermixture of land and water, continent, river, and sea.

But though the existence of a true Placoid, a real vertebrated fish, in the Cambrian limestone of Bala, and of true wood at the base of the Old Red Sandstone, are utterly incompatible with the development hypothesis, its supporters, thus driven to the wall, may take shelter under the vague and unquestioned truth that the lower plants and animals preceded the higher, and that the order of creation was fish, reptiles, birds, mammalia, quadrumana, and man. From this resource, too, our author has cut off his opponents, and proceeds to show that such an order of creation, “at once wonderful and beautiful,” does not afford even the slightest presumption in favor of the hypothesis which it is adduced to support.

This argument is carried on in a popular and amusing dialogue in the eleventh chapter. Mr. Miller shows, in the clearest manner, that “superposition is not parental relation,” or that an organism lying above another gives us no ground for believing that the lower organism was the parent of the higher. The theorist, however, looks only at those phases of truth which are in unison with his own views; and, when truth presents no such favorable aspect, he finally wraps himself up in the folds of ignorance and ambiguity—the winding-sheet of error refuted and exposed. We have not yet penetrated, says he, in feeble accents, to the formations which represent the dawn of being, and the simplest organism may yet be detected beneath the lowest fossiliferous rocks. This undoubtedly may be, and Sir Charles Lyell and Mr. Leonard Horner are of opinion that such rocks may yet be discovered; while Sir Roderick Murchison and Professor Sedgwick and Mr. Miller are of an opposite opinion. But even were such rocks discovered to-morrow, it would not follow that their organisms gave the least support to the development hypothesis. In the year 1837, when fishes were not discovered in the Upper Silurian rocks, the theorist would have rightly predicted the existence of lower fossiliferous beds; but when they are discovered, and their fossils examined, they furnish the strongest argument that could be desired against the theory they were expected to sustain. This fact, no doubt, is so far in favor of the supposition that there may be still lower fossil-bearing strata; but, as Mr. Miller observes, “The pyramid of organized existence, as it ascends into the by-past eternity, inclines sensibly towards its apex,—that apex of ‘beginning’ on which, on far other than geological grounds, it is our privilege to believe. The broad base of the superstructure planted on the existing scene stretches across the entire scale on life, animal and vegetable; but it contracts as it rises into the past;—man,—the quadrumana,—the quadrupedal man,—the bird and the reptile are each in succession struck from off its breadth, till we at length see it with the vertebrata, represented by only the fish, narrowing as it were to a point; and though the clouds of the upper region may hide its apex, we infer, from the declination of its sides, that it cannot penetrate much farther into the profound.”

In our author’s next chapter, the twelfth of the series, he proceeds to examine the “Lamarckian hypothesis of the origin of plants, and its consequences.”

In his thirteenth chapter, on “The two Floras, marine and terrestrial,” he has shown that all our experience is opposed to the opinion, that the one has been transmuted into the other. If the marine had been converted into terrestrial vegetation, we ought to have, in the Lake of Stennis, for example, plants of an intermediate character between the algæ of the sea, and the monocotyledons of the lake. But no such transition-plants are found. The algæ, as our author observes, become dwarfish and ill-developed. They cease to exist as the water becomes fresher, “until at length we find, instead of the brown, rootless, flowerless fucoids and confervæ of the ocean, the green, rooted, flowering flags, rushes, and aquatic grasses of the fresh water. Many thousands of years have failed to originate a single intermediate plant.” The same conclusion may be drawn from the character of the vegetation along the extensive shores of Britain and Ireland. No botanist has ever found a single plant in the transition state.

The fourteenth chapter of the “Footprints” will be perused with great interest by the general reader. It is a powerful and argumentative exposure of the development hypothesis, and of the manner in which the subject has been treated in the “Vestiges.” Whether we consider it in its nature, in its history, or in the character of the intellects with whom it originated, or by whom it has been received and supported, Mr. Miller has shown that it has nothing to recommend it. It existed as a wild dream before Geology had any being as a science. It was broached more than a century ago by De Maillet, who knew nothing of the geology even of his day. In a translation of his Telhamed, published in 1750, Mr. Miller finds very nearly the same account given of the origin of plants and animals, as that in the “Vestiges,” and in which the sea is described as that “great and fruitful womb of nature, in which organization and life first begin.” Lamarck, though a skilful botanist and conchologist, was unacquainted with geology; and as he first published his development hypothesis in 1802, (an hypothesis identical with that of the “Vestiges,”) it is probable that he was not then a very skilful zoologist. Nor has Professor Oken any higher claims to geological acquirements. He confesses that he wrote the first edition of his work in a kind of inspiration! and it is not difficult to estimate the intelligence of the inspiring idol that announced to the German sage that the globe was a vast crystal, a little flawed in the facets, and that quartz, feldspar, and mica, the three constituents of granite, were the hail-drops of heavy showers of stone that fell into the original ocean, and accumulated into rocks at the bottom!

Such is the unscientific parentage of the theories promulgated in the “Vestiges.” But the author of this work appeals in the first instance to science. Astronomy, Geology, Botany, and Zoology are called upon to give evidence in his favor; but the astronomer, geologist, botanist, and the zoologist, all refuse him their testimony, deny his premises, and reject his results. “It is not,” as Mr. Miller happily observes, “the illiberal religionist that casts him off. It is the inductive philosopher.” Science addresses him in the language of the possessed: “The astronomer I know, and the geologist I know; but who are ye?” Thus left alone in a cloud of star-dust, or in brackish water between the marine and terrestrial flora, he “appeals from science to the want of it,” casts a stone at our Scientific Institutions, and demands a jury of “ordinary readers,” as the only “tribunal” by which “the new philosophy is to be truly and righteously judged.”

The last and fifteenth chapter of Mr. Miller’s work, “On the Bearing of Final Causes on Geologic History,” if read with care and thought, will prove at once delightful and instructive. The principle of final causes, or the conditions of existence, affords a wide scope to our reason in Natural History, but especially in Geology. It becomes an interesting inquiry, if any reason can be assigned why at certain periods species began to exist, and became extinct after the lapse of lengthened periods of time, and why the higher classes of being succeeded the lower in the order of creation? The incompleteness of geological science, however, does not permit us to remove, for the present, the veil which hangs over this mysterious chronology; but our author is of opinion that in about a quarter of a century, in a favored locality like the British Islands, geological history “will assume a very extraordinary form.”

It is a singular fact, which will yet lead to singular results, that Cuvier’s arrangement of the four classes of vertebrate animals should exhibit the same order as that in which they are found in the strata of the earth. In the fish, the average proportion of the brain to the spinal cord is only as 2 to 1. In the reptile, the ratio is 2½ to 1. In the bird, it is as 3 to 1. In the mammalia, it is as 4 to 1; and in man, it is as 23 to 1. No less remarkable is the fœtal progress of the human brain. It first becomes a brain resembling that of a fish; then it grows into the form of that of a reptile; then into that of a bird; then into that of a mammiferous quadruped, and finally it assumes the form of a human brain, “thus comprising in its fœtal progress an epitome of geological history, as if man were in himself a compendium of all animated nature, and of kin to every creature that lives.”

With these considerations, Mr. Miller has brought his subject to the point at which Science in its onward progress now stands. It is to embryology we are in future to look for further information upon the most intimate relations which exist between all organized beings. We may fairly entertain the hope that the time is not far when we shall not only fully understand the Plan of Creation, but even lift some corner of the veil which has hitherto prevented us from forming adequate ideas of the first introduction of animal and vegetable life upon earth, and of the changes which both kingdoms have undergone in the succession of geological ages.

L. AGASSIZ.

Cambridge, September, 1850.

CONTENTS

LIST OF WOOD-CUTS

STROMNESS AND ITS ASTEROLEPIS.
THE LAKE OF STENNIS.

When engaged in prosecuting the self-imposed task of examining in detail the various fossiliferous deposits of Scotland, in the hope of ultimately acquainting myself with them all, I extended my exploratory ramble, about two years ago, into the Mainland of Orkney, and resided for some time in the vicinity of Stromness.

This busy seaport town forms that special centre, in this northern archipelago, from which the structure of the entire group can be most advantageously studied. The geology of the Orkneys, like that of Caithness, owes its chief interest to the immense development which it exhibits of one formation,—the Lower Old Red Sandstone,—and to the extraordinary abundance of its vertebrate remains. It is not too much to affirm, that in the comparatively small portion which this cluster of islands contains of the third part of a system regarded only a few years ago as the least fossiliferous in the geologic scale, there are more fossil fish enclosed than in every other geologic system in England, Scotland, and Wales, from the Coal Measures to the Chalk inclusive. Orkney is emphatically, to the geologist, what a juvenile Shetland poetess designates her country, in challenging for it a standing independent of the “Land of Cakes,”—a “Land of Fish;” and, were the trade once fairly opened up, could supply with ichthyolites, by the ton and the ship-load, the museums of the world. Its various deposits, with all their strange organisms, have been uptilted from the bottom against a granitic axis, rather more than six miles in length by about a mile in breadth, which forms the great back-bone of the western district of Pomona; and on this granitic axis—fast jammed in between a steep hill and the sea—stands the town of Stromness. Situated thus at the bottom of the upturned deposits of the island, it occupies exactly such a point of observation as that which the curious eastern traveller would select, in front of some huge pyramid or hieroglyphic-covered obelisk, as a proper site for his tent. It presents, besides, not a few facilities for studying with the geological phenomena, various interesting points in physical science of a cognate character. Resting on its granitic base, in front of the strangely sculptured pyramid of three broad tiers,—red, black, and gray,—which the Old Red Sandstone of these islands may be regarded as forming, it is but a short half mile from the Great Conglomerate base of the formation, and scarcely a quarter of a mile more from the older beds of its central flagstone deposit; while an hour’s sail on the one hand opens to the explorer the overlying arenaceous deposit of Hoy, and an hour’s walk on the other introduces him to the Loch of Stennis, with its curiously mixed flora and fauna. But of the Loch of Stennis and its productions more anon.

The day was far spent when I reached Stromness: but as I had a fine bright evening still before me, longer by some three or four degrees of north latitude than the midsummer evenings of the south of Scotland, I set out, hammer in hand, to examine the junction of the granite and the Great Conglomerate, where it has been laid bare by the sea along the low promontory which forms the western boundary of the harbor. The granite here is a ternary of the usual components, somewhat intermediate in grain and color between the granites of Peterhead and Aberdeen; and the conglomerate consists of materials almost exclusively derived from it,—evidence enough of itself, that when this ancient mechanical deposit was in course of forming, the granite—exactly such a compound then as it is now—was one of the surface rocks of the locality, and much exposed to disintegrating influences. This conglomerate base of the Lower Old Red Sandstone of Scotland—which presents, over an area of many thousand square miles, such an identity of character, that specimens taken from the neighborhood of Lerwick, in Shetland, or of Gamrie, in Banff, can scarce be distinguished from specimens detached from the hills which rise over the Great Caledonian Valley, or from the cliffs immediately in front of the village of Contin—seems to have been formed in a vast oceanic basin of primary rock,—a Palæozoic Hudson’s or Baffin’s Bay,—partially surrounded, mayhap, by primary continents, swept by numerous streams, rapid and headlong, and charged with the broken debris of the inhospitable regions which they drained. The graptolite bearing grauwacke of Banffshire seems to have been the only fossiliferous rock that occurred throughout the entire extent of this ancient northern basin; and its few organisms now serve to open the sole vista through which the geological explorer to the north of the Grampians can catch a glimpse of an earlier period of existence than that represented by the ichthyolites of the Lower Old Red Sandstone.

Very many ages must have passed ere, amid waves and currents, the water-worn debris which now forms the Great Conglomerate could have accumulated over tracts of sea-bottom from ten to fifteen thousand square miles in area, to its present depth of from one to four hundred feet. At length, however, a thorough change took place; but we can only doubtfully speculate regarding its nature or cause. The bottom of the Palæozoic basin became greatly less exposed. Some protecting circle of coast had been thrown up around it; or, what is perhaps more probable, it had sunk to a profounder depth, and the ancient shores and streams had receded, through the depression, to much greater distances. And, in consequence, the deposition of rough sand and rolled pebbles was followed by a deposition of mud. Myriads of fish, of forms the most ancient and obsolete, congregated on its banks or sheltered in its hollows; generation succeeded generation, millions and tens of millions perished mysteriously by sudden death; shoals after shoals were annihilated; but the productive powers of nature were strong, and the waste was kept up. But who among men shall reckon the years or centuries during which these races existed, and this muddy ocean of the remote past spread out to unknown and nameless shores around them? As in those great cities of the desert that lie uninhabited and waste, we can but conjecture their term of existence from the vast extent of their cemeteries. We only know that the dark, finely-grained schists in which they so abundantly occur must have been of comparatively slow formation, and that yet the thickness of the deposit more than equals the height of our loftiest Scottish mountains. It would seem as if a period equal to that in which all human history is comprised might be cut out of a corner of the period represented by the Lower Old Red Sandstone, and be scarce missed when away; for every year during which man has lived upon earth, it is not improbable that the Pterichthys and its contemporaries may have lived a century. Their last hour, however, at length came. Over the dark-colored ichthyolitic schists so immensely developed in Caithness and Orkney, there occurs a pale-tinted, unfossiliferous sandstone, which in the island of Hoy rises into hills of from fourteen to sixteen hundred feet in height; and among the organisms of those newer formations of the Old Red which overlie this deposit, not a species of ichthyolite identical with the species entombed in the lower schists has yet been detected. In the blank interval which the arenaceous deposit represents, tribes and families perished and disappeared, leaving none of their race to succeed them, that other tribes and families might be called into being, and fall into their vacant places in the onward march of creation.

Such, so far as the various hieroglyphics of the pile have yet rendered their meanings to the geologist, is the strange story recorded on the three-barred pyramid of Stromness. I traced the formation upwards this evening along the edges of the upturned strata, from where the Great Conglomerate leans against the granite, till where it merges into the ichthyolitic flagstones; and then pursued these from older and lower to newer and higher layers, desirous of ascertaining at what distance over the base of the system its more ancient organisms first appear, and what their character and kind. And, embedded in a grayish-colored layer of hard flag, somewhat less than a hundred yards over the granite, and about a hundred and sixty feet over the upper stratum of the conglomerate, I found what I sought,—a well-marked bone,—in all probability the oldest vertebrate remain yet discovered in Orkney. What, asks the reader, was the character of this ancient organism of the Palæozoic basin?

As shown by its cancellated texture, palpable to the naked eye, and still more unequivocally by the irregular complexity of fabric which it exhibits under the microscope,—by its speck-like life-points or canaliculi, that remind one of air-bubbles in ice,—its branching channels, like minute veins, through which the blood must once have flown,—and its general groundwork of irregular lines of corpuscular fibre, that wind through the whole like currents in a river studded with islands,—it was as truly osseous in its composition as the solid bones of any of the reptiles of the Secondary, or the quadrupeds of the Tertiary periods. And in form it closely resembled a large roofing-nail. With this bone our more practised palæontologists are but little acquainted, for no remains of the animal to which it belonged have yet been discovered in Britain to the south of the Grampians,[3] nor, except in the Old Red Sandstone of Russia, has it been detected any where on the Continent. Nor am I aware that, save in the accompanying wood-cut, (fig. 1,) it has ever been figured. The amateur geologists of Caithness and Orkney have, however, learned to recognize it as the “petrified nail.” The length of the entire specimen in this instance was five seven eighth inches, the transverse breadth of the head two inches and a quarter, and the thickness of the stem nearly three tenth parts of an inch. This nail-like bone formed a characteristic portion of the Asterolepis,—so far as is yet known, the most gigantic ganoid of the Old Red Sandstone, and, judging from the place of this fragment, apparently one of the first.

Fig. 1.

INTERNAL RIDGE OF HYOID PLATE OF ASTEROLEPSIS.[4]

(One third the natural size, linear.)

There were various considerations which led me to regard the “petrified nail” in this case as one of the most interesting fossils I had ever seen; and, before quitting Orkney, to pursue my explorations farther to the south, I brought two intelligent geologists of the district,[5] to mark its place and character, that they might be able to point it out to geological visitors in the future, or, if they preferred removing it to their town museum, to indicate to them the stratum in which it had lain. It showed me, among other things, how unsafe it is for the geologist to base positive conclusions on merely negative data. Founding on the fact that, of many hundred ichthyolites of the Lower Old Red Sandstone which I had disinterred and examined, all were of comparatively small size, while in the Upper Old Red many of the ichthyolites are of great mass and bulk, I had inferred that vertebrate life had been restricted to minuter forms at the commencement than at the close of the system. It had begun, I had ventured to state in the earlier editions of a little work on the “Old Red Sandstone,” with an age of dwarfs, and had ended with an age of giants. And now, here, at the very base of the system, unaccompanied by aught to establish the contemporary existence of its dwarfs,—which appear, however, in an overlying bed about a hundred feet higher up,—was there unequivocal proof of the existence of one of the most colossal of its giants. But not unfrequently, in the geologic field, has the practice of basing positive conclusions on merely negative grounds led to a misreading of the record. From evidence of a kind exactly similar to that on which I had built, it was inferred, some two or three years ago, that there had lived no reptiles during the period of the Coal Measures, and no fish in the times of the Lower Silurian System.

I extended my researches, a few days after, in an easterly direction from the town of Stromness, and walked for several miles along the shores of the Loch of Stennis,—a large lake about fourteen miles in circumference, bare and treeless, like all the other lakes and lochs of Orkney, but picturesque of outline, and divided into an upper and lower sheet of water by two low, long promontories, that jut out from opposite sides, and so nearly meet in the middle as to be connected by a thread-like line of road, half mound, half bridge. “The Loch of Stennis,” says Mr. David Vedder, the sailor-poet of Orkney, “is a beautiful Mediterranean in miniature.” It gives admission to the sea by a narrow strait, crossed, like that which separates the two promontories in the middle, by a long rustic bridge; and, in consequence of this peculiarity, the lower division of the lake is salt in its nether reaches and brackish in its upper ones, while the higher division is merely brackish in its nether reaches, and fresh enough in its upper ones to be potable. Viewed from the east, in one of the long, clear, sunshiny evenings of the Orkney summer, it seems not unworthy the eulogium of Vedder. There are moory hills and a few rude cottages in front; and in the background, some eight or ten miles away, the bold, steep mountain masses of Hoy; while on the promontories of the lake, in the middle distance, conspicuous in the landscape, from the relief furnished by the blue ground of the surrounding waters, stand the tall gray obelisks of Stennis—one group on the northern promontory, the other on the south,—

“Old even beyond tradition’s breath.”

The shores of both the upper and lower divisions of the lake were strewed, at the time I passed, by a line of wrack, consisting, for the first few miles from where the lower loch opens to the sea, of only marine plants, then of marine plants mixed with those of fresh-water growth, and then, in the upper sheet of water, of lacustrine plants exclusively. And the fauna of the loch is, I was informed, of as mixed a character as its flora,—the marine and fresh-water animals having each their own reaches, with certain debatable tracts between, in which each kind expatiates with more or less freedom, according to its specific nature and constitution,—some of the sea-fish advancing far on the fresh water, and others, among the proper denizens of the lake, encroaching far on the salt. The common fresh-water eel strikes out, I was told, farthest into the sea-water; in which, indeed, reversing the habits of the salmon, it is known in various places to deposit its spawn. It seeks, too, impatient of a low temperature, to escape from the cold of winter, by taking refuge in water brackish enough, in a climate such as ours, to resist the influence of frost. Of the marine fish, on the other hand, I found that the flounder got greatly higher than any of the others, inhabiting reaches of the lake almost entirely fresh. I have had an opportunity elsewhere of observing a curious change which fresh water induces in this fish. In the brackish water of an estuary, the animal becomes, without diminishing in general size, thicker and more fleshy than when in its legitimate habitat, the sea: but the flesh loses in quality what it gains in quantity;—it grows flabby and insipid, and the margin-fin lacks always its strip of transparent fat. But the change induced in the two floras of the lake—marine and lacustrine—is considerably more palpable and obvious than that induced in its two faunas. As I passed along the strait, through which it gives admission to the sea, I found the commoner fucoids of our sea-coasts streaming in great luxuriance in the tideway, from the stones and rocks of the bottom. I marked, among the others, the two species of kelp-weed, so well known to our Scotch kelp-burners,—Fucus nodosus and Fucus vesiculosus,—flourishing in their uncurtailed proportions; and the not inelegant Halidrys siliquosa, or “tree in the sea,” presenting its amplest spread of pod and frond. A little farther in, Halidrys and Fucus nodosus disappear, and Fucus vesiculosus becomes greatly stunted, and no longer exhibits its characteristic double rows of bladders. But for mile after mile it continues to exist, blent with some of the hardier confervæ, until at length it becomes as dwarfish and nearly as slim of frond as the confervæ themselves; and it is only by tracing it through the intermediate forms that we succeed in convincing ourselves that, in the brown stunted tufts of from one to three inches in length, which continue to fringe the middle reaches of the lake, we have in reality the well-known Fucus before us. Rushes, flags, and aquatic grasses may now be seen standing in diminutive tufts out of the water; and a terrestrial vegetation at least continues to exist, though it can scarce be said to thrive, on banks covered by the tide at full. The lacustrine flora increases, both in extent and luxuriance, as that of the sea diminishes; and in the upper reaches we fail to detect all trace of marine plants: the algæ, so luxuriant of growth along the straits of this “miniature Mediterranean,” altogether cease; and a semi-aquatic vegetation attains, in turn, to the state of fullest development any where permitted by the temperature of this northern locality. A memoir descriptive of the Loch of Stennis, and its productions, animal and vegetable, such as old Gilbert White of Selborne could have produced, would be at once a very valuable and curious document, important to the naturalist, and not without its use to the geological student.

I know not how it may be with others; but the special phenomena connected with Orkney that most decidedly bore fruit in my mind, and to which my thoughts have most frequently reverted, were those exhibited in the neighborhood of Stromness. I would more particularly refer to the characteristic fragment of Asterolepis, which I detected in its lower flagstones, and to the curiously mixed, semi-marine, semi-lacustrine vegetation of the Loch of Stennis. Both seem to bear very directly on that development hypothesis,—fast spreading among an active and ingenious order of minds, both in Britain and America, and which has been long known on the Continent,—that would fain transfer the work of creation from the department of miracle to the province of natural law, and would strike down, in the process of removal, all the old landmarks, ethical and religious.

THE DEVELOPMENT HYPOTHESIS, AND ITS CONSEQUENCES.

Every individual, whatever its species or order, begins and increases until it attains to its state of fullest development, under certain fixed laws, and in consequence of their operation. The microscopic monad develops into a fœtus, the fœtus into a child, the child into a man; and, however marvellous the process, in none of its stages is there the slightest mixture of miracle; from beginning to end, all is progressive development, according to a determinate order of things. Has Nature, during the vast geologic periods, been pregnant, in like manner, with the human race? and is the species, like the individual, an effect of progressive development, induced and regulated by law? The assertors of the revived hypothesis of Maillet and Lamarck reply in the affirmative. Nor, be it remarked, is there positive atheism involved in the belief. God might as certainly have originated the species by a law of development, as he maintains it by a law of development; the existence of a First Great Cause is as perfectly compatible with the one scheme as with the other; and it may be necessary thus broadly to state the fact, not only in justice to the Lamarckians, but also fairly to warn their non-geological opponents, that in this contest the old anti-atheistic arguments, whether founded on the evidence of design, or on the preliminary doctrine of final causes, cannot be brought to bear.

There are, however, beliefs, in no degree less important to the moralist or the Christian than even that in the being of a God, which seem wholly incompatible with the development hypothesis. It, during a period so vast as to be scarce expressible by figures, the creatures now human have been rising, by almost infinitesimals, from compound microscopic cells,—minute vital globules within globules, begot by electricity on dead gelatinous matter,—until they have at length become the men and women whom we see around us, we must hold either the monstrous belief, that all the vitalities, whether those of monads or of mites, of fishes or of reptiles, of birds or of beasts, are individually and inherently immortal and undying, or that human souls are not so. The difference between the dying and the undying,—between the spirit of the brute that goeth downward, and the spirit of the man that goeth upward,—is not a difference infinitesimally, or even atomically small. It possesses all the breadth of the eternity to come, and is an infinitely great difference. It cannot, if I may so express myself, be shaded off by infinitesimals or atoms; for it is a difference which—as there can be no class of beings intermediate in their nature between the dying and the undying—admits not of gradation at all. What mind, regulated by the ordinary principles of human belief, can possibly hold that every one of the thousand vital points which swim in a drop of stagnant water are inherently fitted to maintain their individuality throughout eternity? Or how can it be rationally held that a mere progressive step, in itself no greater or more important than that effected by the addition of a single brick to a house in the building state, or of a single atom to a body in the growing state, could ever have produced immortality? And yet, if the spirit of a monad or of a mollusc be not immortal, then must there either have been a point in the history of the species at which a dying brute—differing from its offspring merely by an inferiority of development, represented by a few atoms, mayhap by a single atom—produced an undying man, or man in his present state must be a mere animal, possessed of no immortal soul, and as irresponsible for his actions to the God before whose bar he is, in consequence, never to appear, as his presumed relatives and progenitors the beasts that perish. Nor will it do to attempt escaping from the difficulty, by alleging that God at some certain link in the chain might have converted a mortal creature into an immortal existence, by breathing into it a “living soul;” seeing that a renunciation of any such direct interference on the part of Deity in the work of creation forms the prominent and characteristic feature of the scheme,—nay, that it constitutes the very nucleus round which the scheme has originated. And thus, though the development theory be not atheistic, it is at least practically tantamount to atheism. For, if man be a dying creature, restricted in his existence to the present scene of things, what does it really matter to him, for any one moral purpose, whether there be a God or no? If in reality on the same religious level with the dog, wolf, and fox, that are by nature atheists,—a nature most properly coupled with irresponsibility,—to what one practical purpose should he know or believe in a God whom he, as certainly as they, is never to meet as his Judge? or why should he square his conduct by the requirements of the moral code, farther than a low and convenient expediency may chance to demand?[6]

Nor does the purely Christian objection to the development hypothesis seem less, but even more insuperable than that derived from the province of natural theology. The belief which is perhaps of all others most fundamentally essential to the revealed scheme of salvation, is the belief that “God created man upright,” and that man, instead of proceeding onward and upward from this high and fair beginning, to a yet higher and fairer standing in the scale of creation, sank and became morally lost and degraded. And hence the necessity for that second dispensation of recovery and restoration which forms the entire burden of God’s revealed message to man. If, according to the development theory, the progress of the “first Adam” was an upward progress, the existence of the “second Adam”—that “happier man,” according to Milton, whose special work it is to “restore” and “regain the blissful seat” of the lapsed race—is simply a meaningless anomaly. Christianity, if the development theory be true, is exactly what some of the more extreme Moderate divines of the last age used to make it—an idle and unsightly excrescence on a code of morals that would be perfect were it away.

I may be in error in taking this serious view of the matter; and, if so, would feel grateful to the man who could point out to me that special link in the chain of inference at which, with respect to the bearing of the theory on the two theologies—natural and revealed—the mistake has taken place. But if I be in error at all, it is an error into which I find not a few of the first men of the age,—represented, as a class, by our Professor Sedgwicks and Sir David Brewsters,—have also fallen; and until it be shown to be an error, and that the development theory is in no degree incompatible with a belief in the immortality of the soul—in the responsibility of man to God as the final Judge—or in the Christian scheme of salvation—it is every honest man’s duty to protest against any ex parte statement of the question, that would insidiously represent it as ethically an indifferent one, or as unimportant in its theologic bearing, save to “little religious sects and scientific coteries.” In an address on the fossil flora, made in September last by a gentleman of Edinburgh to the St. Andrew’s Horticultural Society, there occurs the following passage on this subject: “Life is governed by external conditions, and new conditions imply new races; but then as to their creation, that is the ‘mystery of mysteries.’ Are they created by an immediate fiat and direct act of the Almighty? or has He originally impressed life with an elasticity and adaptability, so that it shall take upon itself new forms and characters, according to the conditions to which it shall be subjected? Each opinion has had, and still has, its advocates and opponents; but the truth is, that science, so far as it knows, or rather so far as it has had the honesty and courage to avow, has yet been unable to pronounce a satisfactory decision. Either way, it matters little, physically or morally, either mode implies the same omnipotence, and wisdom, and foresight, and protection; and it is only your little religious sects and scientific coteries which make a pother about the matter,—sects and coteries of which it may be justly said, that they would almost exclude God from the management of his own world, if not managed and directed in the way that they would have it.” Now, this is surely a most unfair representation of the consequences, ethical and religious involved in the development hypothesis. It is not its compatibility with belief in the existence of a First Great Cause that has to be established, in order to prove it harmless; but its compatibility with certain other all-important beliefs, without which simple Theism is of no moral value whatever—a belief in the immortality and responsibility of man, and in the scheme of salvation by a Mediator and Redeemer. Dissociated from these beliefs, a belief in the existence of a God is of as little ethical value as a belief in the existence of the great sea-serpent.

Let us see whether we cannot determine what the testimony of Geology, on this question of creation by development, really is. It is always perilous to under-estimate the strength of an enemy; and the danger from the development hypothesis to an ingenious order of minds, smitten with the novel fascinations of physical science, has been under-estimated very considerably indeed. Save by a few studious men, who to the cultivation of Geology and the cognate branches add some acquaintance with metaphysical science, the general correspondence of the line of assault taken up by this new school of infidelity, with that occupied by the old, and the consequent ability of the assailants to bring, not only the recently forged, but also the previously employed artillery into full play along its front, has not only not been marked, but even not so much as suspected. And yet, in order to show that there actually is such a correspondence, it can be but necessary to state, that the great antagonist points in the array of the opposite lines, are simply the law of development versus the miracle of creation. The evangelistic Churches cannot, in consistency with their character, or with a due regard to the interests of their people, slight or overlook a form of error at once exceedingly plausible and consummately dangerous, and which is telling so widely on society, that one can scarce travel by railway or in a steamboat, or encounter a group of intelligent mechanics, without finding decided trace of its ravages.

But ere the Churches can be prepared competently to deal with it, or with the other objections of a similar class which the infidelity of an age so largely engaged as the present in physical pursuits will be from time to time originating they must greatly extend their educational walks into the field of physical science. The mighty change which has taken place during the present century, in the direction in which the minds of the first order are operating, though indicated on the face of the country in characters which cannot be mistaken, seems to have too much escaped the notice of our theologians. Speculative theology and the metaphysics are cognate branches of the same science; and when, as in the last and the preceding ages, the higher philosophy of the world was metaphysical, the Churches took ready cognizance of the fact, and, in due accordance with the requirements of the time, the battle of the Evidences was fought on metaphysical ground. But, judging from the preparations made in their colleges and halls, they do not now seem sufficiently aware—though the low thunder of every railway, and the snort of every steam engine, and the whistle of the wind amid the wires of every electric telegraph, serve to publish the fact—that it is in the departments of physics, not of metaphysics, that the greater minds of the age are engaged,—that the Lockes, Humes, Kants, Berkeleys, Dugald Stewarts, and Thomas Browns, belong to the past,—and that the philosophers of the present time, tall enough to be seen all the world over, are the Humboldts, the Aragos, the Agassizes, the Liebigs, the Owens, the Herschels, the Bucklands, and the Brewsters. In that educational course through which, in this country, candidates for the ministry pass, in preparation for their office, I find every group of great minds which has in turn influenced and directed the mind of Europe for the last three centuries, represented, more or less adequately, save the last. It is an epitome of all kinds of learning, with the exception of the kind most imperatively required, because most in accordance with the genius of the time. The restorers of classic literature—the Buchanans and Erasmuses—we see represented in our Universities by the Greek and what are termed the Humanity courses; the Galileos, Boyles, and Newtons, by the Mathematical and Natural Philosophy courses; and the Lockes, Kants, Humes, and Berkeleys, by the Metaphysical course. But the Cuviers, the Huttons, the Cavendishes, and the Watts, with their successors, the practical philosophers of the present age,—men whose achievements in physical science we find marked on the surface of the country in characters which might be read from the moon,—are not adequately represented. It would be perhaps more correct to say, that they are not represented at all;[7] and the clergy, as a class, suffer themselves to linger far in the rear of an intelligent and accomplished laity—a full age behind the requirements of the time. Let them not shut their eyes to the danger which is obviously coming. The battle of the Evidences will have as certainly to be fought on the field of physical science, as it was contested in the last age on that of the metaphysics. And on this new arena the combatants will have to employ new weapons, which it will be the privilege of the challenger to choose. The old, opposed to these, would prove but of little avail. In an age of muskets and artillery, the bows and arrows of an obsolete school of warfare would be found greatly less than sufficient, in the field of battle, for purposes either of assault or defence.

“There are two kinds of generation in the world,” says Professor Lorenz Oken, in his “Elements of Physio-philosophy;” “the creation proper, and the propagation that is sequent thereupon—or the generatio originaria and secundaria. Consequently, no organism has been created of larger size than an infusorial point. No organism is, nor ever has one been created, which is not microscopic. Whatever is larger has not been created, but developed. Man has not been created, but developed.” Such, in a few brief dogmatic sentences, is the development theory. What, in order to establish its truth, or even to render it in some degree probable, ought to be the geological evidence regarding it? The reply seems obvious. In the first place, the earlier fossils ought to be very small in size; in the second, very low in organization. In cutting into the stony womb of nature, in order to determine what it contained mayhap millions of ages ago, we must expect, if the development theory be true, to look upon mere embryos and fœtuses. And if we find, instead, the full grown and the mature, then must we hold that the testimony of Geology is not only not in accordance with the theory, but in positive opposition to it. Such, palpably, is the principle on which, in this matter, we ought to decide. What are the facts?

The oldest organism yet discovered in the most ancient geological system of Scotland in which vertebrate remains occur, seems to be the Asterolepis of Stromness. After the explorations of many years over a wide area, I have detected none other equally low in the system; nor have I ascertained that any brother-explorer in the same field has been more fortunate. It is, up to the present time, the most ancient Scotch witness of the great class of fishes that can in this case be brought into court; nay, it is in all probability the oldest ganoid witness the world has yet produced; for there appears no certain trace of this order of fishes in the great Silurian system which lies underneath, and in which, so far as geologists yet know, organic existence first began. How, then, on the two relevant points—bulk and organization—does it answer to the demands of the development hypothesis? Was it a mere fœtus of the finny tribe, of minute size, and imperfect, embryonic faculty? Or was it of at least the ordinary bulk, and, for its class, of the average organization? May I solicit the forbearance of the non-geological reader, should my reply to these apparently simple questions seem unnecessarily prolix and elaborate? Peculiar opportunities of observation, and the possession of a set of unique fossils, enable me to submit to our palæontologists a certain amount of information regarding this ancient ganoid, which they will deem at once interesting and new; and the bearing of my statements on the general argument will, I trust, become apparent as I proceed.

THE RECENT HISTORY OF THE ASTEROLEPIS.
ITS FAMILY.

It had been long known to the continental naturalists, that in certain Russian deposits, very extensively developed, there occur in considerable abundance certain animal organisms; but for many years neither their position nor character could be satisfactorily determined. By some they were placed too high in the scale of organized being; by others too low. Kutorga, a writer not very familiarly known in this country, described the remains as those of mammals;—the Russian rocks contained, he said, bones of quadrupeds, and, in especial, the teeth of swine: whereas Lamarck, a better known authority, though not invariably a safe one,—for he had a trick of dreaming when wide awake, and of calling his dreams philosophy,—assigned to them a place among the corals. They belonged, he asserted, as shown by certain star-like markings with which they are fretted, to the Polyparia. He even erected for their reception a new genus of Astrea, which he designated, from the little rounded hillock which rises in the middle of each star, the genus Monticularia. It was left to a living naturalist, M. Eichwald, to fix their true position zoologically among the class of fishes, and to Sir Roderick Murchison to determine their position geologically as ichthyolites of the Old Red Sandstone.

Sir Roderick, on his return from his great Russian campaigns, in which he fared far otherwise than Napoleon, and accomplished more, submitted to Agassiz a series of fragments of these gigantic Ganoids; and the celebrated ichthyologist, who had been introduced little more than a twelvemonth before to the Pterichthys of Cromarty, was at first inclined to regard them as the remains of a large cuirassed fish of the Cephalaspian type, but generically new. Under this impression he bestowed upon the yet unknown ichthyolite of which they had formed part, the name Chelonichthys, from the resemblance borne by the broken plates to those of the carapace and plastron of some of the Chelonians. At this stage, however, the Russian Old Red yielded a set of greatly finer remains than it had previously furnished; and of these casts were transmitted by Professor Asmus, of the University of Dorpat, to the British and London Geological Museums, and to Agassiz. “I knew not at first what to do,” says the ichthyologist, “with bones of so singular a conformation that I could refer them to no known type.” Detecting, however, on their exterior surfaces the star-like markings which had misled Lamarck, and which he had also detected on the lesser fragments submitted to him by Sir Roderick, he succeeded in identifying both the fragments and bones as remains of the same genus and on ascertaining that M. Eichwald had bestowed upon it, from these characteristic sculpturings, the generic name Asterolepis, or star-scale, he suffered the name which he himself had originated to drop. Even this second name, however, which the ichthyolite still continues to bear, is in some degree founded in error. Its true scales, as I shall by and by show, were not stelliferous, but fretted by a peculiar style of ornament, consisting of waved anastomosing ridges, breaking atop into angular-shaped dots, scooped out internally like the letter V; and were evidently intermediate in their character between the scales which cover the Glyptolepis and those of the Holoptychius. And the stellate markings which M. Eichwald graphically describes as minute paps rising out of the middle of star-like wreaths of little leaflets, were restricted to the dermal plates of the head.

Agassiz ultimately succeeded in classing the bones which had at first so puzzled him, into two divisions—interior and dermal; and the latter he divided yet further, though not without first lodging a precautionary protest, founded on the extreme obscurity of the subject, into cranial and opercular. Of the interior bones he specified two,—a super-scapular bone, (supra-scapulaire,)—that bone which in osseous fishes completes the scapular arch or belt, by uniting the scapula to the cranium; and a maxillary or upper jaw-bone. But his world-wide acquaintance with existing fishes could lend him no assistance in determining the places of the dermal bones: they formed the mere fragments of a broken puzzle, of which the key was lost. Even in their detached and irreducible state, however, he succeeded in basing upon them several shrewd deductions. He inferred, in the first place, that the Asterolepis was not, as had been at first supposed, a cuirassed fish, which took its place among the Cephalaspians, but a strongly helmed fish of that Cœlacanth family to which the Holoptychius and Glyptolepis belong; in the second, that, like several of its bulkier cogeners, it was in all probability a broad, flat-headed animal; and, in the third, that as its remains are found associated in the Russian beds with numerous detached teeth of large size,—the boar tusks of Kutorga—which present internally that peculiar microscopic character on which Professor Owen has erected his Dendrodic or tree-toothed family of fishes,—it would in all likelihood be found that both bones and teeth belonged to the same group. “It appears more than probable,” he said, “that one day, by the discovery of a head or an entire jaw, it will be shown that the genera Dendrodus and Asterolepis form but one.” As we proceed, the reader will see how justly the ichthyologist assigned to the Asterolepis its place among the Cœlacanths, and how entirely his two other conjectures regarding it have been confirmed. “I have had in general,” he concluded, “but small and mutilated fragments of the creature’s bones submitted to me, and of these, even the surface ornaments not well preserved; but I hope the immense materials with which the Old Red Sandstone of Russia has furnished the savans of that country will not be lost to science; and that my labors on this interesting genus, incomplete as they are, will excite more and more the attention of geologists, by showing them how ignorant we are of all the essential facts concerning the history of the first inhabitants of our globe.”

I know not what the savans of Russia have been doing for the last few years; but mainly through the labors of an intelligent tradesman of Thurso, Mr. Robert Dick,—one of those working men of Scotland of active curiosity and well-developed intellect, that give character and standing to the rest,—I am enabled to justify the classification and confirm the conjectures of Agassiz. Mr. Dick, after acquainting himself, in the leisure hours of a laborious profession, with the shells, insects, and plants of the northern locality in which he resides, had set himself to study its geology; and with this view he procured a copy of the little treatise on the Old Red Sandstone to which I have already referred, and which was at that time, as Agassiz’s Monograph of the Old Red fishes had not yet appeared, the only work specially devoted to the palæontology of the system, so largely developed in the neighborhood of Thurso. With perhaps a single exception,—for the Thurso rocks do not yet seem to have yielded a Pterichthys,—he succeeded in finding specimens, in a state of better or worse keeping, of all the various ichthyolites which I had described as peculiar to the Lower Old Red Sandstone. He found, however, what I had not described,—the remains of apparently a very gigantic ichthyolite; and, communicating with me through the medium of a common friend, he submitted to me, in the first instance, drawings of his new set of fossils; and ultimately, as I could arrive at no satisfactory conclusion from the drawings, he with great liberality made over to me the fossils themselves. Agassiz’s Monograph was not yet published; nor had I an opportunity of examining, until about a twelvemonth after, the casts, in the British Museum, of the fossils of Professor Asmus. Besides, all the little information, derived from various sources, which I had acquired respecting the Russian Chelonichthys,—for such was its name at the time,—referred it to the cuirassed type, and served but to mislead. I was assured, for instance, that Professor Asmus regarded his set of remains as portions of the plates and paddles of a gigantic Pterichthys, of from twenty to thirty feet in length. And so, as I had recognized in the Thurso fossils the peculiarities of the Holoptychian (Cœlacanth) family, I at first failed to identify them with the remains of the great Russian fish. All the larger bones sent me by Mr. Dick were, I found, cerebral; and the scales associated with these indicated, not a cuirass-protected, but a scale-covered body and exhibited, in their sculptured and broadly imbricated surfaces, the well-marked Cœlacanth style of disposition and ornament. But though I could not recognize in either bones or scales the remains of one ichthyolite more of the Old Red Sandstone, “that could be regarded as manifesting as peculiar a type among fishes as do the Ichthyosauri and Plesiosauri among reptiles,”[8] I was engaged at the time in a course of inquiry regarding the cerebral development of the earlier vertebrata, that made me deem them scarce less interesting than if I could. Ere, however, I attempt communicating to the reader the result of my researches, I must introduce him, in order that he may be able to set out with me to the examination of the Asterolepis from the same starting-point, to the Cœlacanth family,—indisputably one of the oldest, and not the least interesting, of its order.

Fig. 2.

a. Shagreen of the Thornback (Raja clavata.)

b. Shagreen of Sphagodus,—a placoid of the Upper Silurian.[9]

So far as is yet known, all the fish of the earliest fossiliferous system belonged to the placoid or “broad plated” order,—a great division of fishes, represented in the existing seas by the Sharks and Rays,—animals that to an internal skeleton of cartilage unite a dermal covering of points, plates, or spines of enamelled bone, and have their gills fixed. The dermal or cuticular bones of this order vary greatly in form, according to the species or family: in some cases they even vary, according to their place, on the same individual. Those button-like tubercles, for instance, with an enamelled thorn, bent like a hook, growing out of the centre of each, which run down the back and tail, and stud the pectorals of the thorn-back, (Raja clavata,) differ very much from the smaller thorns, with star-formed bases, which roughen the other parts of the creature’s body; and the bony points which mottle the back and sides of the sharks are, in most of the known species, considerably more elongated and prickly than the points which cover their fins, belly, and snout. The extreme forms, however, of the shagreen tubercle or plate seem to be those of the upright prickle or spine on the one hand, and of the slant-laid, rhomboidal, scale-shaped plate on the other. The minuter thorns of the ray (fig. 2, a) exemplify the extreme of the prickly type; the fins, abdomen, and anterior part of the head of the spotted dog-fish (Scyllium stellare) are covered by lozenge-shaped little plates, which glisten with enamel, and are so thickly set that they cover the entire surface of the skin, (fig. 3, b,)—and these seem equally illustrative of the scale-like form. They are shagreen points passing into osseous scales, without, however, becoming really such; though they approach them so nearly in the shape and disposition of their upper disks, that the true scales, also osseous, of the Acanthodes sulcatus, (fig. 3, a,) a Ganoid of the Coal Measures, can scarce be distinguished from them, even when microscopically examined. It is only when seen in section that the distinctive difference appears. The true scale of the Acanthodes, though considerably elevated in the centre, seems to have been planted on the skin; whereas the scale-like shagreen of the dog-fish is elevated over it on an osseous pedicle or footstalk (fig. 5, a) as a mushroom is elevated over the sward on its stem; and the base of the stalk is found to resemble in its stellate character that of a shagreen point of the prickly type. The apparent scale is, we find, a bony prickle bent at right angles a little over its base, and flattened into a rhomboidal disk atop.

Fig. 3.

a. Scales of Acanthodes sulcatus.

b. Shagreen of Scyllium stellare, (Snout.)

(Mag. eight diameters.)

Fig. 4.

a. Scales of Cheiracanthus microlepidotus.

b. Shagreen of Spinax Acanthias. (Snout.)

(Mag. eight diameters.)

Fig. 5.

a. Section of shagreen of Scyllium stellare.

b. Under surface of do.

c. Section of scales of Cheiracanthus microlepidotus.

d. Under surface of do.

(Mag. eight diameters.)

In small fragments of shagreen, (fig. 2 b) which have been detected in the bone-bed of the Upper Ludlow Rocks, (Upper Silurian,) and constitute the most ancient portions of this substance known to the palæontologist, the osseous tubercles are, as in the minuter spikes of the ray, of the upright thorn-like type; they merely serve to show that the placoids of the first period possessed, like those of the existing seas, an ability of secreting solid bone on their cuticular surfaces; and that, though at least such of them as have bequeathed to us specimens of their dermal armature possessed it in the form farthest removed from that of their immediate successors the ganoid fishes, they resembled them not less in the substance of which their dermoskeletal, than in that of which their endoskeletal, parts were composed. For the internal skeleton in both orders, during these early ages, seems to have been equally cartilaginous, and the cuticular skeleton equally osseous. In the ichthyolitic formation immediately over the Silurians,—that of the Lower Old Red Sandstone,—the Ganoids first appear; and the members of at least one of the families of the deposit, the Acanths,—a family rich in genera and species,—seem to have formed connecting links between this second order and their placoid predecessors. They were covered with true scales (fig. 4, a,) and their free gills were protected by gill-covers; and so they must be regarded as real Ganoids but as the shagreen of the spotted dog-fish nearly approaches, in form and character, to ganoid scales, without being really such, the scales of this family, on the other hand, approached equally near, without changing their nature, to the shagreen of the Placoids, especially to that of the spiked dogfish, (Spinax Acanthias.) (Fig. 4, b.) We even find on their under surfaces what seems to be an approximation to the characteristic footstalk. They so considerably thicken in the middle from their edges inwards, (fig. 5, c,) as to terminate in their centres in obtuse points. With these shagreen-like scales, the heads, bodies, and fins of all the species of at least two of the Acanth genera,—Cheiracanthus and Diplacanthus,—were as thickly covered as the heads, bodies, and fins of the sharks are with their shagreen; and so slight was the degree of imbrication, that the portion of each scale overlaid by the two scales in immediate advance of it did not exceed the one twelfth part of its entire area. In the scale of the Cheiracanthus we find the covered portion indicated by a smooth, narrow band, that ran along its anterior edges, and which the furrows that fretted the exposed surface did not traverse. It may be added, that both genera had the anterior edge of their fins armed with strong spines,—a characteristic of several of the Placoid families.

Fig. 6.

a. Scales of Osteolepis macrolepidotus.

b. Scales of an undescribed species of Glyptolepis.[10]

(The single scales mag. two diameters;—the others nat. size.)

In the Dipterian genera Osteolepis and Diplopterus the scales were more unequivocally such than in the Acanths, and more removed from shagreen. The under surface of each was traversed longitudinally by a raised bar, which attached it to the skin, and which, in the transverse section, serves to remind one of the shagreen footstalk. They are, besides, of a rhomboidal form; and, when seen in the finer specimens, lying in their proper places on what had been once the creature’s body, they seem merely laid down side by side in line, like those rows of glazed tiles that pave a cathedral floor; but on more careful examination, we find that each little tile was deeply grooved on its higher side and end, (for it lay diagonally in relation to the head,) like the flags of a stone roof, (fig. 6, a,)—that its lateral and anterior neighbors impinged upon it along these grooves to the extent of about one third its area,—and that it impinged, in turn, to the same extent on the scales that bordered on it posteriorly and latero-posteriorly. Now, in the Cœlacanth family, (and on this special point the foregoing remarks are intended to bear,) the scales, which were generally of a round or irregularly oval form, (fig. 6, b,) overlapped each other to as great an extent as in any of the existing fishes of the Cycloid or Ctenoid orders,—to as great an extent, for instance, as in the carp, salmon, or herring. In a slated roof there is no part on which the slates do not lie double, and along the lower edge of each tier they lie triple;—there is more of slate covered than of slate seen: whereas in a tile-roof, the covered portion is restricted to a small strip running along the top and one of the edges of each tile, and the tiles do not lie double in more than the same degree in which the slates lie triple. The scaly cover of the two genera of Dipterians to which I have referred was a cover on the tile-roof principle; and this is an exceedingly common characteristic of the scales of the Ganoids. The scaly cover of the Cœlacanths, on the other hand, was a cover on the slate-roof principle;—there was in some of their genera about one third more of each scale covered than exposed; and this is so rare a ganoidal mode of arrangement, that, with the exception of the Dipterus,—a genus which, though it gives its name to the Dipterian sept, differed greatly from every other Dipterian,—I know not, beyond the limits of the ancient Cœlacanth family, a single Ganoid that possessed it. The bony covering of the Cœlacanths was farthest removed in character from shagreen, as that of their contemporaries the Acanths approximated to it most nearly; they were, in this respect, the two extremes of their order; and did we find the Cœlacanths in but the later geological formations, while the Acanths were restricted to the earlier, it might be argued by assertors of the development hypothesis, that the amply imbricated, slate-like scale of the latter had been developed in the lapse of ages from the shagreen tubercle, by passing in its downward course—broadening and expanding as it descended—through the minute, scarcely imbricated disks of the Acanths, and the more amply imbricated tile-like rhombs of the Dipterians and Palæonisci, until it had reached its full extent of imbrication in the familiar modern type exemplified in both the Cœlacanths and the ordinary fishes. But such is not the order which nature has observed;—the two extremes of the ganoid scale appear together in the same early formation: both become extinct at a period geologically remote; and the ganoid scales of the existing state of things which most nearly resemble those of ancient time are scales formed on the intermediate or tile-roof principle.

The scales of the Cœlacanths were, in almost all the genera which compose the family, of great size; in some species, of the greatest size to which this kind of integument ever attained. Of a Cœlacanth of the Coal Measures, the Holoptychius Hibberti, the scales in the larger specimens were occasionally from five to six inches in diameter. Even in the Holoptychius nobilissimus, in an individual scarcely exceeding two and a half feet in length, they measured from an inch and a half to an inch and three quarters each way. In the splendid specimen of this last species, in the British Museum, there occur but fourteen scales between the ventrals, though these lie low on the creature’s body, and the head; and in a specimen of a smaller species,—the Holoptychius Andersoni,—but about seventeen. The exposed portion of the scale was in most species of the family curiously fretted by intermingled ridges and furrows, pits and tubercles, which were either boldly relieved, as in the Holoptychius, or existed, as in the Glyptolepis, as slim, delicately chiselled threads, lines, and dots. The head was covered by strong plates, which were roughened with tubercles either confluent or detached, or hollowed, as in the Bothriolepis, into shallow pits. The jaws were thickly set with an outer range of true fish teeth, and more thinly with an inner range of what seem reptile teeth, that stood up, tall and bulky, behind the others, like officers on horseback seen over the heads of their foot-soldiers in front. The double fins,—pectorals and ventrals,—were characterized each by a thick, angular, scale-covered centre, fringed by the rays; and they must have borne externally somewhat the form of the sweeping paddles of the Ichthyosaurian genus,—a peculiarity shared also by the double fins of the Dipterus. The single fins, in all the members of the family of which specimens have been found sufficiently entire to indicate the fact, were four in number,—an anal, a caudal, and two dorsal fins; and, with the exception of the anterior dorsal, which was comparatively small, and bent downwards along the back, as if its rays had been distorted when young,[11] they were all of large size. They crowded thickly on the posterior portion of the body,—the anterior dorsal opposite the ventrals, and the posterior dorsal opposite the anal fin. The fin-rays of the various members of the family, and such of their spinous processes as have been detected, were hollow tubular bones; or rather, like the larger pieces in the framework of the Placoids, they were cartilaginous within, and covered externally by a thin osseous crust or shell, which alone survives; and to this peculiarity they owe their family name, Cœlacanth, or “hollow-spine.” The internal hollow, i. e. cartilaginous centre, was, however, equally a characteristic of the spinous processes of the Coccosteus. In their general proportions, the Cœlacanths, if we perhaps except one species,—the Glyptolepis microlepidotus,—were all squat, robust, strongly-built fishes, of the Dirk Hatterick or Balfour-of-Burley type; and not only in the larger specimens gigantic in their proportions, but remarkable for the strength and weight of their armor, even when of but moderate stature. The specimen of Holoptychius nobilissimus in the British Museum could have measured little more than three feet from snout to tail when most entire; but it must have been nearly a foot in breadth, and a bullet would have rebounded flattened from its scales. And such was that ancient Cœlacanth family, of which the oldest of our Scotch Ganoids,—the Asterolepis of Stromness,—formed one of the members, and which for untold ages has had no living representative.

Let us now enter on our proposed inquiry regarding the cerebral development of the earlier vertebrata, and see whether we cannot ascertain after what manner the first true brains were lodged, and what those modifications were which their protecting box, the cranium, received in the subsequent periods. Independently of its own special interest, the inquiry will be found to have a direct bearing on our general subject.

CEREBRAL DEVELOPMENT OF THE EARLIER VERTEBRATA.
ITS APPARENT PRINCIPLE.

It is held by a class of naturalists, some of them of the highest standing, that the skulls of the vertebrata consist, like the columns to which they are attached, of vertebral joints, composed each, in the more typical forms of head, as they are in the trunk, of five parts or elements,—the centrum or body, the two spinous processes which enclose the spinal cord, and the two ribs. These cranial vertebræ, four in number, correspond, it is said, to the four senses that have their seat in the head: there is the nasal vertebra, the centrum of which is the vomer, its spinal processes the nasal and ethmoid bones, and its ribs the upper jaws; there is the ocular vertebra, the centrum of which is the anterior portion of the sphenoid bone, its spinal processes the frontals, and its ribs the under jaws; there is the lingual vertebra, the centrum of which is the posterior sphenoid bone, its spinal processes the parietals, and its ribs the hyoid and branchial bones,—portions of the skeleton largely developed in fishes; and, lastly, there is the auditory vertebra, the centrum of which is the base of the occipital bone, and its spinal processes the occipital crest, and which in the osseous fishes bears attached to it, as its ribs, the bones of the scapular ring. And the cerebral segments thus constructed we find represented in typical diagrams of the skull, as real vertebræ. Professor Owen, in his lately published treatise on “The Nature of Limbs,”—work charged with valuable fact, and instinct with philosophy,—figures in his draught of the archetypal skeleton of the vertebrata, the four vertebræ of the head, in a form as unequivocally such as any of the vertebræ of the neck or body.

Now, for certain purposes of generalization, I doubt not that the conception may have its value. There are in all nature and in all philosophy certain central ideas of general bearing, round which, at distances less or more remote, the subordinate and particular ideas arrange themselves,

“Cycle and epicycle, orb in orb.”

In the classifications of the naturalist, for instance, all species range round some central generic idea; all genera round some central idea, to which we give the name of order; all orders round some central idea of class; all classes round some central idea of division; and all divisions round the interior central idea which constitutes a kingdom. Sir Joshua Reynolds forms his theory of beauty on this principle of central ideas. “Every species of the animal, as well as of the vegetable creation,” he remarks, “may be said to have a fixed or determinate form, towards which nature is continually inclining, like various lines terminating in a centre; or it may be compared to pendulums vibrating in different directions over one central point, which they all cross, though only one of their number passes through any other point.” He instances, in illustrating his theory, the Grecian beau ideal of the human nose, as seen in the statues of the Greek deities. It formed a straight line; whereas all deformity of nose is of a convex or concave character, and occasioned by either a rising above or a sinking below this medial line of beauty. And it may be of use, as it is unquestionably of interest, to conceive, after this manner, of a certain type of skeleton, embodying, as it were, the central or primary type of all vertebral skeletons, and consisting of a double range of rings, united by the bodies of the vertebræ, as the two rings of a figure 8 are united at their point of junction; the upper ring forming the enclosure of the brain,—spinal, and cephalic; the lower that of the viscera,—respiratory, circulatory, and digestive. Such is the idea embodied in Professor Owen’s archetypal skeleton. It is a series of vertebræ composing double rings,—their brain-rings comparatively small in the vertebræ of the trunk, but of much greater size in the vertebræ of the head. But it must not be forgotten, that central ideas, however necessary to the classification of the naturalist, are not historic facts. We may safely hold, with the philosophic painter, that the outline of the typical human nose is a straight line; but it would be very unsafe to hold, as a consequence, that the first men had all straight noses. And when we find it urged by at least one eminent assertor of the development hypothesis,—Professor Oken,—that light was the main agent in developing the substance of nerve,—that the nerves, ranged in pairs, in turn developed the vertebræ, each vertebra being but “the periphery or envelope of a pair of nerves,”—and that the nerves of those four senses of smell, sight, taste, and hearing, which, according to the Professor, “make up the head,” originated the four cranial vertebræ which constitute the skull,—it becomes us to test the central idea, thus converted into a sort of historic myth, by the realities of actual history. What, then, let us inquire, is the real history of the cerebral development of the vertebrata, as recorded in the rocks of the earlier geologic periods?

Fig. 7.

Osseous points of placoid cranium.[12]

(Mag. twelve diameters)

Though the vertebrata existed in the ichthyic form throughout the vastly extended Silurian period, we find in that system no remains of the cranium: the Silurian fishes seem, as has been already said, ([page 53],) to have been exclusively Placoid, and the purely cartilaginous box formed by nature for the protection of the brain in this order has in no case been preserved. Teeth, and, in at least one or two instances, the minute jaws over which they were planted have been found, but no portion of the skull. We know, however, that in the fishes of the same order which now exist, the cranium consists of one undivided piece of a cartilaginous substance, set thickly over its outer surface with minute polygonal points of bone, (fig. 7,) composed internally of star-like rays, that radiate from the centre of ossification, and that present, in consequence, seen through a microscope, the appearance of the polygonal cells of a coral of the genus Astrea. The pattern induced is that of stars set within polygons. Along the sides or top of this unbroken cranial box, that exhibits no mark of suture, we find the perforations through which the nerves of smell, sight, taste, and hearing passed from the brain outwards, and see that they have failed to originate distinct vertebral envelopes for themselves;—they all lodge in one undivided mansion-house, and have merely separate doors. We find, further, that the homotypal ribs of the entire cranium consist, not of four, but simply of a single pair, attached to the occiput, and which serves both to suspend the jaws, upper and nether, in their place under the middle of the head, and to lend support to the hyoid and branchial framework; while the scapular ring we find existing, as in the higher vertebrata, not as a cerebral, but as a cervical or dorsal appendage. In the wide range of the animal kingdom there are scarce any two pieces of organization that less resemble one another in form than the vertebræ of the placoids resemble their skulls; and the difference is not merely external, but extends to even their internal construction. In both skull and vertebræ we detect an union of bone and cartilage; but the bone of each vertebra forms an internal continuous nucleus, round which the cartilage is arranged, whereas in the skulls it is the cartilage that is internal, and the bone is spread in granular points over it. If we dip the body of one of the dorsal vertebræ of a herring into melted wax, and then withdraw it, we will find it to represent in its crusted state the vertebral centrum of a Placoid,—soft without, and osseous within; but in order to represent the placoid skull, we would have first to mould it out of one unbroken piece of wax, and then to cover it over with a priming of bone-dust. And such is the effect of this arrangement, that, while the skull of a Placoid, exposed to a red heat, falls into dust, from the circumstance that the supporting framework on which the granular bone was arranged perishes in the fire, the vertebral centrum, whose internal framework is itself bone, and so not perishable, comes out in a state of beautiful entireness,—resembling in the thornback a squat sand-glass, elegantly fenced round by the lateral pillars, (fig. 8, b;) and in the dog-fish (a) a more elongated sand-glass, in which the lateral pillars are wanting. Such are the heads and vertebral joints of the existing Placoids; and such, reasoning from analogy, seem to have been the character and construction of the heads and vertebral joints of the Placoids of the Silurian period,—earliest-born of the Vertebrata.

Fig. 8.

a. Osseous centrum of Spinax Acanthias.

b. Osseous centrum of Raja clavata.

(Nat. size.)

The most ancient brain-bearing craniums that have come down to us in the fossil state, are those of the Ganoids of the Lower Old Red Sandstone; and in these fishes the true skull appears to have been as entirely a simple cartilaginous box, as that of the Placoids of either the Silurian period or of the present time, or of those existing Ganoids, the sturgeons. In the Lower Old Red genera Cheiracanthus and Diplacanthus, though the heads are frequently preserved as amorphous masses of colored matter, we detect no trace of internal bone, save perhaps in the gill-covers of the first-named genus, which were fringed by from eighteen to twenty minute osseous rays. The cranium seems to have been covered, as in the shark family, by skin, and the skin by minute shagreen-like scales; and all of the interior cerebral framework which appears underneath exists simply as faint impressions of an undivided body, covered by what seem to be osseous points,—the bony molecules, it is probable, which encrusted the cartilage. The jaws, in the better specimens, are also preserved in the same doubtful style, and this state of keeping is the common one in deposits in which every true bone, however delicate, presents an outline as sharp as when it occupied its place in the living animal. The dermal or skin-skeleton of both genera, which consisted, as has been shown ([pages 55, 56]) of shagreen-like osseous scales and slender spines, both brilliantly enamelled, is preserved entire; where as the interior framework of the head exists as mere point speckled impressions; and the inference appears unavoidable that parts which so invariably differ in their state of keeping now, must have essentially differed in their substance originally.

Fig. 9.

a. Portion of caudal fin of Cheiracanthus.[13]

b. Portion of caudal fin of Cheirolepis Cummingiæ.

(Mag. three diameters.)

Now, in the Cheiracanthus we detect the first faint indications of a peculiar arrangement of the dermal skeleton, in relation to certain parts of the skeleton within, which—greatly more developed in some of its contemporaries—led to important results in the general structure of these Ganoids, and furnishes the true key to the character of the early ganoid head. In such of the existing Placoids as I have had an opportunity of examining, the only portions of the dermal skeleton of bone which conform in their arrangement to portions of the interior skeleton of cartilage, are the teeth, which are always laid on a base of skin right over the jaws: there is also an approximation to arrangement of a corresponding kind, though a distant one, in those hook-armed tubercles of certain species of rays which run along the vertebral column; but in the shagreen by which the creatures are covered I have been able to detect no such arrangement. Whether it occurs on the fins, the body, or the head, or in the scale form, or in that of the prickle, it manifests the same careless irregularity. And on the head and body of the Cheiracanthus, and on all its fins save one, the shagreen-like scales, though laid down more symmetrically in lines than true shagreen, manifested an equal absence of arrangement in relation to the framework within. On that one fin, however;—the caudal,—the scales, passing from their ordinary rhomboidal to a more rectangular form, ranged themselves in right lines over the internal rays, (fig. 9, a,) and imparted to these such strength as a splint of wood or whalebone fastened over a fractured toe or finger imparts to the injured digit,—a provision which was probably rendered necessary in the case of this important organ of motion, from the circumstance that it was the only fin which the creature possessed that was not strengthened and protected anteriorly by a strong spine. In the Cheirolepis,—a contemporary fish, characterized, like its cogeners the Cheiracanthus and Diplacanthus, by shagreen-like scales, but in which the spines were wanting,—we find a farther development of the provision. In all the fins the richly-enamelled dermal-covering was arranged in lines over the rays, (fig. 9, b;) and the scale, which assumes in the fins, like the scales on the tail of the Cheiracanthus, though somewhat more irregularly, a rectangular shape, is so considerably elongated, that it assumes for its normal character as a scale, that of the joint of an external ray. A similar arrangement of external protection takes place in this genus over the bones of the head; the cartilaginous jaws receive their osseous dermal covering, and, with these, the hyoid bones, the opercules, and the cranium. And it is in these dermal plates, which covered an interior skull, of which, save in one genus,—the Dipterus,—not a vestige remains in any of the Old Red fishes thus protected, that we first trace what seem to be the homologues of the cranial bones of the osseous fishes,—at least their homologues so far as the cuticular can represent the internal. They appear for the first time, not as modified spinous processes, broadened, as in the carapace of the Chelonians, into osseous plates, but like those corneous external plates of this order of reptiles, (known in one species as the tortoise-shell of commerce,) the origin of which is purely cuticular, and which evince so little correspondence in their divisions with the sutures of the bones on which they rest, that they have been instanced, in their relation to the joinings beneath, as admirable illustrations of the cross-banding of the mechanician.

In the heads of the osseous fishes, the cranium proper, though consisting, like the skulls of birds, reptiles, and mammals, of several bones, exists from snout to nape, and from mastoid to mastoid, as one unbroken box; whereas all the other bones of the head, such as the maxillaries and intermaxillaries, the lower jaws, the opercular appendages, the branchial arches, and the branchiostegous rays, are connected but by muscle and ligament, and fall apart under the putrefactive influences, or in the process of boiling. This unbroken box, which consists, in the cod, of twenty-five bones, is the homologue of that cranial box of the Placoids which consists of one entire piece, and the homotype, according to Oken, of the bodies and spinal processes of four vertebræ; while the looser bones which drop away represent their ribs. The upper surface of the box,—that extending from the nasal bone to the nape,—is the only part over which a dermal buckler could be laid, as it is the only part with which the external skin comes in contact; and so it is between this upper surface and the cranial bucklers of the earlier Ganoids that we have to institute comparisons. For it is a curious fact, that, with the exception of the Old Red genera Acanthodus, Cheiracanthus, and Diplacanthus,[14] all the Ganoids of the period in which Ganoids first appear have dermal bucklers placed right over their true skulls, and that these, though as united in their parts as the bones proper to the cranium in quadrupeds and fishes, are composed of several pieces, furnished each with its independent centre of ossification. The Dipterians, the Cœlacanths, the Cephalaspians, and at least one genus placed rather doubtfully among the Acanths,—the genus Cheirolepis,—all possessed cranial bucklers extending from the nape to the snout, in which the plates, various, in the several genera, in form and position, were fast soldered together, though in every instance the lines of suture were distinctly marked.

Fig. 10.

UPPER SURFACE OF CRANIUM OF COD.[15]

A, Occipital bone. B, B, Parietals. C, C, C, Superior frontal. D, D, Anterior frontal. I, Nasal bone. F, F, Posterior frontals. E, E, Mastoid bones. 2, 2, Eye orbits. a, a, Par-occipital bones.

On each side of this external cranium the various cerebral plates, like the corresponding cerebral ribs in the osseous fishes, were free, at least not anchylosed together; and some of their number unequivocally performed, in part at least, the functions of two of these cerebral ribs, viz. the upper and under jaws, with the functions of the opercular appendages attached to the latter. In the cod, as in most other osseous fishes, the upper portion of the cranium consists of thirteen bones, which represent, however, only seven bones in the human skull,—the nasal, the frontal, the two parietal, the occipital, and one-half the two temporal bones. And whereas in man, and in most of the mammals, there are four of these placed in the medial line,—the four which, according to the assertors of the vertebral theory, form the spinal crests of the four cerebral vertebræ,—in the cod there are but three. The super-occipital bone, A, (fig. 10,) pieces on to the superior frontal, C, C, C; and the parietals, B, B, which in the human subject from the upper and middle portions of the cranial vault, are thrust out laterally and posteriorly, and take their places, in a subordinate capacity, on each side of the super-occipital. This is not an invariable arrangement among fishes;—in the carp genus, for instance, the parietals assume their proper medial place between the occipital and frontal bones; but so very general is the displacement, that Professor Owen regards it as characteristic of the great ichthyic class, and as the first example in the vertebrata, reckoning from the lower forms upwards, of a sort of natural dislocation among the bones,—“a modification,” he remarks, “which, sometimes accompanied by great change of place, has tended most to obscure the essential nature of parts, and their true relations to the archetype.”

Fig. 11.

CRANIAL BUCKLER OF COCCOSTEUS DECIPIENS.

a, a, Points of attachment to the cuirass which covered the upper part of the creature’s body.

Of all the cerebral bucklers of the first ganoid period, that which best bears comparison with the cranial front of the cod is the buckler of the Coccosteus, (fig. 11.) The general proportions of this portion of the ancient Cephalaspian head differ very considerably from those of the corresponding part in the modern cycloid one; but in their larger divisions, the modern and the ancient answer bone to bone. Three osseous plates in the Coccosteus, A, C, I, the homologues, apparently, of the occipital, frontal, and nasal bones, range along the medial line. The apparent homologues of the parietals, B, B, occupy the same position of lateral displacement as the parietals of the cod and of so many other fishes. The posterior frontals, F, and the anterior frontals, D, also occupy places relatively the same, though the latter, which are of greater proportional size, encroach much further, laterally and posteriorly, on the superior frontal C, C, C, and sweep entirely round the upper half of the eye orbits, 2, 2. The apparent homologue of the mastoid bone, E, which also occupies its proper place, joins posteriorly to a little plate, a, imperfectly separated in most specimens from the parietal, but which seems to represent the par-occipital bone; and it is a curious circumstance, that as, in many of the osseous fishes, it is to these bones that the forks of the scapular arch are attached, they unite in the Coccosteus in furnishing, in like manner, a point of attachment to the cuirass which covered the upper part of the creature’s body. Of the true internal skull of the Coccosteus there remains not a vestige Like that of the sturgeon, it must have been a perishable cartilaginous box.

Fig. 12.

CRANIAL BUCKLER OF OSTEOLEPIS.

In the Osteolepis,—an animal the whole of whose external head I have, at an expense of some labor, and from the examination of many specimens, been enabled to restore,—the cranial buckler (fig. 12) was divided in a more arbitrary style; and we find that an element of uncertainty mingles with our inferences regarding it, from the circumstance that some of its lines of division, especially in the frontal half, were not real sutures, but formed merely a kind of surface-tatooing, resorted to as if for purposes of ornament. The cranial buckler of the Asterolepis exhibited, as I shall afterwards have occasion to show, a similar peculiarity;—both had their pseudo-sutures, resembling those false joints introduced by the architect into his rusticated basements, in order to impart the necessary aspect of regularity to what is technically termed the coursing and banding of the fabric. We can however, determine, notwithstanding the induced obscurity that the buckler of the Osteolepis was divided transversely in the middle into two main parts or segments,—an occipital part, C, and a frontal part, A; and that the occipital segment seems to include also the parietal and mastoid plates, and the frontal segment to comprise, with its own proper plates, not only the nasal plate, but also the representative of the anterior part of the vomer. All, however, is obscure. But in our uncertainty regarding the homologies of the divisions of this dermal buckler, let us not forget the homology of the buckler itself, as a whole, with the upper surface of the true cranium in the osseous fishes. Though frequently crushed and broken, it exists in all the finer specimens of my collection as a symmetrically arranged collocation of enamelled plates, as firmly united into one piece, though they all indicate their distinct centres of ossification, as the corresponding surface of the cranium in the carp or cod. The lateral curves in the frontal part immediately opposite the lozenge-shaped plate in the centre, show the position of the eyes, which were placed in this genus, as in some of the carnivorous turtles, immediately over the mouth,—an arrangement common to almost all the Ganoids of the Lower Old Red Sandstone. The nearly semicircular termination of the buckler formed the creature’s snout; and in the Osteolepis, as in the Glyptolepis and the Diplopterus, it was armed on the under side, like the vomer of so many of the osseous fishes, with sharp teeth. Some of my specimens indicate the nasal openings a little in advance of the eyes. The nape of the creature was covered by three detached plates, (9, 9, 9, fig. 13,) which rested upon anterior dorsal scales, and whose homologies, in the osseous fishes, may possibly be found in those bones which, uniting the shoulder-bones to the head, complete the scapular belt or ring. The operculum we find represented by a single plate (8) which had attached to it, as its sub-operculum, a plate (13) of nearly equal size, (see figs. 14 and 15.) Four small plates (2, 4, 5) formed the under curve of the eyes, described in many of the osseous fishes by a chain of small bones or ossicles; a considerably larger plate (6) occupied the place of the preopercular bone; while the intermaxillaries had their representatives in well-marked plates, (3, 3,) which, in the genera Osteolepis, Diplopterus, and Glyptolepis, we find bristling so thickly with teeth along their lower edges, as to remind us of the miniature saws employed by the joiner in cutting out circular holes. These external intermaxillaries did not, as in the perch or cod, meet in front of the nasal bone and vomer, but joined on at the side, a little in advance of the eyes, leaving the rounded termination of the cranial buckler, which, like the intermaxillaries, was thickly fringed with teeth, to form, as has been already said, the creature’s snout.

Fig. 13.

UPPER PART OF HEAD OF OSTEOLEPIS.

The under jaws (10)—strongly-marked bones in at least all the Dipterian and Cœlacanth genera—we find represented externally by massy plates, bearing, like those of the upper jaw, their range of teeth. As shown in a well-preserved specimen of the lower jaw of Holoptychius, in my possession, they were boxes of bone enclosing a bulky nucleus of cartilage, which, in approaching towards the condyloid process, where great strength was necessary, was thickly traversed by osseous cancelli, and passed at the joint into true bone. It is in the under jaws of the earlier Ganoids that we first detect a true union of the external with the internal skeleton,—of the bony plates and teeth, which were mere plates and teeth of the skin, with the osseous, granular walls which enclosed at least all the larger pieces of the cartilaginous framework of the interior. The jaws of the Rays and Sharks, formed of cartilage, and fenced round on their sides and edges by their thin coverings of polygonal, bony points, are wholly internal and skin-covered; whereas the teeth, which rest on the soft cuticular integument right over them, are as purely dermal as the surrounding shagreen. Teeth and shagreen may, we find, be alike stripped off with the skin. Now, in the earlier ganoidal jaw, two sides of the osseous box which it composed,—its outer and under sides,—were mere dermal plates, representative of the skin of the placoids, or of their shagreen; while the other two,—its upper and inner sides,—seem to have been developments of the interior osseous walls which covered the endo-skeletal cartilage. Nor is it unworthy of notice, that the reptile fishes of the period had their ichthyic teeth ranged along the edge of an exterior dermal plate which covered the outer side of the jaw; whereas their reptile teeth were planted on a plate, apparently of interior development, which covered its upper edge. It is further worthy of remark, that while the teeth of the dermal plate,—themselves also dermal,—seem as if they had grown out of it, and formed part of it,—just as the teeth of the Placoids grew out of the skin on which they rest,—the reptile teeth within rested in shallow pits,—the first faint indications of true sockets.

Fig. 14.

UNDER PART OF HEAD OF OSTEOLEPIS.[16]

Fig. 15.

HEAD OF OSTEOLEPIS, SEEN IN PROFILE.

That space included within the arch formed by the sweep of the under jaws, which we find occupied in the osseous fishes by the hyoid bones and the branchiostegous rays, was filled up externally, in the Dipterians and Cœlacanths, and in at least two genera of Cephalaspians, by dermal plates; in some genera, such as the Diplopterus, by three plates; in others, such as the Holoptychius and Glyptolepis, by two; and in the Asterolepis, as we shall afterwards see, by but a single plate. In the Osteolepis these plates were increased to five in number, by the little plates 14, 14, (fig. 14,) which, however, may have been also present in the Diplopterus, though my specimens fail to show them. The general arrangement was of much elegance,—an elegance, however, which, in the accompanying restorations, the dislocation of the free plates, drawn apart to indicate their detached character, somewhat tends to obscure. But the position of the eyes must have imparted to the animal a sinister reptile-like aspect. The profile, (fig. 15,) the result, not of a chance-drawn outline, arbitrarily filled up, but produced by the careful arrangement in their proper places of actually existing plates, serves to show how perfectly the dermo-skeletal parts of the creature were developed. Some of the animals with which we are best acquainted, if represented by but their cuticular skeleton, would appear simply as sets of hoofs and horns. Even the tortoise or pengolin would present about the head and limbs their gaps and missing portions; but the dermo-skeleton of the Osteolepis, composed of solid bone, and burnished with enamel, exhibited the outline of the fish entire, and, with the exception of the eye, the filling up of all its external parts. Presenting outside, in its original state, no fragment of skin or membrane, and with even its most flexible organs sheathed in enamelled bone, the Osteolepis must have very much resembled a fish carved in ivory; and, though so effectually covered, it would have appeared, from the circumstance, that it wore almost all its bone outside, as naked as the human teeth.

Fig. 16.

CRANIAL BUCKLER OF DIPLOPTERUS.

Fig. 17.

CRANIAL BUCKLER OF DIPLOPTERUS.

The cranial buckler of the Diplopterus (fig. 16) somewhat resembled that of its fellow-dipterian the Osteolepis, but exhibited greater elegance of outline. My first perfect specimen, which I owe to the kindness of Mr. John Miller, of Thurso, an intelligent geologist of the north, reminded me, as it glittered in jet-black enamel on its ground of pale gray, of those Roman cuirasses which one sees in old prints, impaled on stakes, as the central objects in warlike trophies formed of spoils taken in battle. The rounded snout represented the chest and shoulders, the middle portion the waist, and the expansion at the nape the piece of dress attached, which, like the Highland kilt, fell adown the thighs. The addition of a fragment of a sleeve, suspended a little over the eye orbits, 2, 2, seemed all that was necessary in order to render the resemblance complete. But as I disinterred the buried edges of the specimen with a graver, the form, though it grew still more elegant, became less that of the ancient coat of armor; the snout expanded into a semicircle; the eye orbits gradually deepened; and the entire fossil became not particularly like any thing but the thing it once was,—the cranial buckler of the Diplopterus. The print (fig. 17) exhibits its true form. It consists of two main divisions, occipital (A) and frontal, (C, fig. 16;) and in each of these we find a pair of smaller divisions, with what seem to be indications of yet further division, marked, not by lines, but by dots; though I have hitherto failed to determine whether the plates which these last indicate possess their independent centres of ossification. Not unfrequently, however, has the comparative anatomist to seek the analogues of two bones in one; nor is it at least more difficult to trace in the faint divisions of the cranial buckler of the Diplopterus, the homologues of the occipital, frontal, parietal, mastoid, and nasal bones, than to recognize the representatives of the carpals of the middle and ring finger in man, in the cannon bone of the fore leg of the ox. I may mention in passing, that the little central plate of the frontal division, (1, fig. 16,) which so nearly corresponds with that of the Osteolepis, occurred, though with considerable variations of form and homology, and some slight difference of position, in all the Ganoids of the Old Red Sandstone whose craniums were covered with an osseous buckler, and that its place was always either immediately between the eyes or a very little over them. Its never-failing recurrence shows that it must have had some meaning, though it may be difficult to say what. In the Coccosteus it takes the form of the male dovetail, which united the nasal plate or snout to the plate representative of the superior frontal. Of the cartilaginous box which formed the interior skull of either Osteolepis, or Diplopterus, or, with but one exception, of the interior skulls of any of their contemporaries, no trace, as I have said, has yet been detected. The solitary exception in the case is, however, one of singular interest.

Fig. 18.

a. Palatal dart-head.

b. Group of palatal teeth.

In a collection of miscellaneous fragments sent me by Mr. Dick from the rocks of Thurso, I detected patches of palatal teeth ranged in nearly the quadratures of circles, and which radiated outwards from the rectangular angle or centre, (fig. 18, b.) And with the patches there occurred plates exactly resembling the barbed head of a dart, (a,) with which I had been previously acquainted, though I had failed to determine their character or place. The excellent state of keeping of some of Mr. Dick’s specimens now enabled me to trace the patches with the dart-head, and several other plates, to a curious piece of palatal mechanism, ranged along the base of a ganoid cranium, covered externally by a brightly enamelled buckler, and to ascertain the order in which patches and plates occurred. And then, though not without some labor, I succeeded in tracing the buckler with which they were associated to the Dipterus,—a fish which, though it has engaged the attention of both Cuvier and Agassiz, has not yet been adequately restored. It is on an ill-preserved Orkney specimen of the cranial buckler of this Ganoid that the ichthyologist has founded his genus Polyphractus; while groupes of its palatal teeth from the Old Red of Russia he refers to a supposed Placoid,—the Ctenodus. But in the earlier stages of palæontological research, mistakes of this character are wholly unavoidable. The palæontologist who did avoid them would be either very unobservant, or at once very rash and very fortunate in his guesses. If, ere an entire skeleton of the Ichthyosaurus had turned up, there had been found in different localities, in the Liasic formation, a beak like that of a porpoise, teeth like that of a crocodile, a head and sternum like that of a lizard, paddles like those of a cetacean, and vertebræ like those of a fish, it would have been greatly more judicious, and more in accordance with the existing analogies, to have erected, provisionally at least, places specifically, or even generically separated, in which to range the separate pieces, than to hold that they had all united in one anomalous genus; though such was actually the fact. And Agassiz, in erecting three distinct genera out of the fragments of a single genus, has in reality acted at once more prudently and more intelligently than if he had avoided the error by rashly uniting parts which in their separate state indicate no tie of connection.

Fig. 19.

CRANIAL BUCKLER OF DIPTERUS.

Fig. 20.

BASE OF CRANIUM OF DIPTERUS.

The cranial buckler of the Dipterus (fig. 19) was, like that of the Diplopterus, of great beauty. In some of the finer specimens, we find the enamel ornately tatooed, within the more strongly-marked divisions, by delicately traced lines, waved and bent, as if upon the principle of Hogarth; and though the lateral plates are numerous and small, and defy the homologies, we may trace in those of the central line, from the snout to the nape, what seem to be the representatives of the frontal, parietal, and occipital bones,—the parietals ranging, as in the skull of the carp and in that of most of the mammals, in their proper place in the medial line. But the under surface of the cranium, armed, as on the upper surface, with plates of bone, exhibited an arrangement still more peculiar, (fig. 20.) Its rectangular patches of palatal teeth, its curious dart-like bone, placed immediately behind these, and attached, as the dart-head is attached to the handle, to a broad lozenge-shaped plate, with two strong osseous processes projecting on either side, forms such a tout ensemble as is unique among fishes. Even here, however, there may be traced at least a shade of homological resemblance to the bones which form the base of the osseous skull. The single lozenge-shaped plate, (A,) with its dart-head, occupies the place of the basi-occipital bone; the posterior portion of the vomer seems represented by a strong bony ridge, extending towards the snout; two separate bones, each bearing one of the angular patches of teeth, corresponds to the sphenoid bone and its alæ; and attached laterally to each of these there is the strong projecting bone, on which the lower jaw appears to have hinged, and which apparently represents the lower part of the temporal bone. Not less singular was the form of the creature’s under jaw, (fig. 21.) I know no other fish-jaw, whether of the recent or the extinct races, that might be so readily mistaken for that of a quadruped. It exhibits not only the condyloid, but also the coronoid processes; and, save that it broadens on its upper edges, where in mammals the grinders are placed, so as to furnish field enough for angular patches of teeth, which correspond with the angular patches in the palate, it might be regarded, found detached, as at least a reptilian, if not mammalian, bone. The disposition of the palatal teeth of the Dipterus will scarce fail to remind the mechanist of the style of grooving resorted to in the formation of mill-stones for the grinding of flour; nor is it wholly improbable that, in correspondence with the rotatory motion of the stones to which the grooving is specially adapted, jaws so hinged may have possessed some such power of lateral motion as that exemplified by the human subject in the use of the molar teeth.

Fig. 21.

UNDER JAW OF DIPTERUS.

The protection afforded by the osseous covering of both the upper and under surface of the cranium of this ichthyolite has resulted, in several instances, in the preservation, though always in a greatly compressed state, of the cranium itself, and the consequent exhibition of two very important cranial cavities, the brain-pan proper, and the passage through which the spinal cord passed into the brain. In the sturgeon the brain occupies nearly the middle of the head; and there is a considerable part of the occipital region traversed by the spine in a curved channel, which, seen in profile, appears wide at the nape, but considerably narrower where it enters the brain-pan, and altogether very much resembling the interior of a miniature hunting-horn. And such exactly was the arrangement of the greater cavities in the head of the Dipterus. The portion of the cranium which was overlaid by what may be regarded as the occipital plate was traversed by a cavity shaped like a Lilliputian bugle-horn; while the hollow in which the brain was lodged lay under the two parietal plates, and the little elliptical plate in the centre. The accompanying print, (fig. 22,) though of but slight show, may be regarded by the reader with some little interest, as a not inadequate representation of the most ancient brain-pan on which human eye has yet looked,—as, in short, the type of cell in which, myriads of ages ago, in at least one genus, that mysterious substance was lodged, on whose place and development so very much in the scheme of creation was destined to depend. The specimen from which the figure is taken was laid open laterally by chance exposure to the waves on the shores of Thurso, another specimen, cut longitudinally by the saw of the lapidary, yields a similar section, but greatly more compressed in the cavities; on which, of course, as unsupported hollows, the compression to which the entire cranium had been exposed chiefly acted. When the top and bottom of a box are violently forced together, it is the empty space which the box encloses that is annihilated in consequence of the violence.

Fig. 22.

LONGITUDINAL SECTION OF HEAD OF DIPTERUS

It is deserving of notice, that the analogies of the cranial cavities in this ancient Ganoid should point so directly on the cranial cavities of that special Ganoid of the present time which unites a true skull of cartilage to a dermal skull of osseous plates,—a circumstance strongly corroborative of the general evidence, negative and positive, on which I have concluded that the true skulls of the first Ganoids were also cartilaginous. It is further worthy of observation, that in all the sections of the cranium of Dipterus which I have yet examined, the internal line is continuous, as in the Placoids, from nape to snout, and that the true skull presents no trace of those cerebral vertebræ of which skulls are regarded by Oken and his disciples as developments. Historically at least, the progress of the ichthyic head seems to have been a progress from simple cartilaginous boxes to cartilaginous boxes covered with osseous plates, that performed the functions whether active or passive, of internal bones; and then from external plates to the interior bones which the plates had previously represented, and whose proper work they had done.

The principle which rendered it necessary that the divisions which exist in the dermal skulls of the first Ganoids should so closely correspond with the divisions which exist in the internal skulls of the osseous fishes of a greatly later period, does not seem to lie far from the surface. Of the solid parts of the ichthyic head, a certain set of pieces afford protection to the brain and cerebral nerves, and to some of the organs of the senses, such as those of seeing and hearing; while another certain set of pieces constitute the framework through which an important class of functions, manducatory and respiratory, are performed. The protective bones of merely passive function are fixed, whereas the bones of active function, such as the jaws, the osseous framework of the opercules, and the hyoid bones, are to the necessary extent free, i. e. capable of independent motion. Of course, the detached character necessary to the free cerebral bones would be equally necessary in cerebral plates united dermally to the pieces of the cartilaginous framework, which performed in the ancient fish the functions of these free bones. And hence jaw plates, opercular plates, and hyoid plates, whose homological relation with recent jaws and opercular and hyoid bones cannot be mistaken. They were operative in performing identical mechanical functions, and had to exist, in consequence, in identical mechanical conditions. And an equally simple, though somewhat different principle, seems to have regulated the divisions of the fixed cranial bucklers of the Old Red Ganoids, and to have determined their homologies with the fixed cerebral bones of the osseous fishes.

These cranial bucklers, extending from nape to snout, protected the exposed upper surface of the cartilaginous skull, and conformed to it in shape, as a helmet conforms to the shape of the head, or a breast-plate to the shape of the chest. And as the cartilaginous heads resembled in general outline the osseous ones, the buckler which covered their upper surface resembled in general outline the upper surface of the osseous skull. It was in no case entirely a flat plate; but in every species rounded over the snout and in most species at the sides; and so, in order that its characteristic proportions might be preserved throughout the various stages of growth in the head which it covered, it had to be formed from several distinct centres of ossification, and to extend in area around the edges of the plates originated from these. The workman finds no difficulty in adding to the size of a piece of straight wall, whether by heightening or lengthening it; but he cannot add to the size of a dome or arch, without first taking it down, and then erecting it anew on a larger scale. In the domes and arches of the animal kingdom, the problem is solved by building them up of distinct pieces, few or many, according to the demands of the figure which they compose, and rendering these pieces capable of increase along their edges. It is on this principle that the Cystidea, the Echinidæ, the Chelonian carapace and plastron, and the skulls of the osseous Vertebrata, are constructed. It is also the principle on which the cranial bucklers of the ancient Ganoids were formed.[17] And from the general resemblance in figure of these bucklers to the upper surface of the osseous skull, the separate parts necessary for the building up of the one were anticipated, by many ages, in the building up of the other; just as we find external arches of stone which were erected two thousand years ago, constructed on the same principle, and relatively of the same parts, as internal arches of brick built in the present age. Doubtless, however, with this mechanical necessity for correspondence of parts in the formation of corresponding erections, there may have mingled that regard for typical resemblance which seems so marked a characteristic of the style, if I may so express myself, in which the Divine Architect gives expression to his ideas. The external osseous buckler He divided after the general pattern which was to be exemplified, in latter times, in the divisions of the internal osseous skull; as if in illustration of that “ideal exemplar” which dwelt in his mind from eternity, and on the palpable existence of which sober science has based deductions identical in their scope and bearing with some of the sublimest doctrines of the theologian. “The recognition,” says Professor Owen, “of an ideal exemplar for the vertebrated animals, proves that the knowledge of such a being as man existed before man appeared; for the Divine mind which planned the archetype also foreknew all its modifications. The archetypal idea was manifested in the flesh, under divers such modifications, upon this planet, long prior to the existence of those animal species that actually exemplify it.”

But while we find place in that geological history in which every character is an organism, for the “ideal exemplar” of Professor Owen, we find no place in it for the vertebræ-developed skull of Professor Oken. The true genealogy of the head runs in an entirely different line. The nerves of the cerebral senses did not, we find, originate cerebral vertebræ, seeing that the heads of the first and second geologic periods had their cerebral nerves, but not their cerebral vertebræ; and that what are regarded as cerebral-vertebræ appear for the first time, not in the early fishes, but in the reptiles of the Coal formation. The line of succession through the fish, indicated by the Continental assertor of the development hypothesis, is a line cut off. All the existing evidence conspires to show that the placoid heads of the Silurian system were, like the placoid heads of the recent period, mere cartilaginous boxes; and that in the succeeding system there existed ganoidal heads, that to the internal cartilaginous box added external plates of bone, the homologues, apparently,—so far at least as the merely cuticular could be representative of the endo-skeletal,—of the opercular, maxillary, frontal, and occipital bones in the osseous fishes of a long posterior period,—fishes that were not ushered upon the scene until after the appearance of the reptile in its highest forms and of even the marsupial quadruped.

THE ASTEROLEPIS, ITS STRUCTURE, BULK, AND ASPECT.

With the reader, if he has accompanied me thus far, I shall now pass on to the consideration of the remains of the Asterolepis. Our preliminary acquaintance with the cerebral peculiarities of a few of its less gigantic contemporaries will be found of use in enabling us to determine regarding a class of somewhat resembling peculiarities which characterized this hugest Ganoid of the Old Red Sandstone.

Fig. 24.

Dermal tubercles of Asterolepis

(Mag. two diameters.)

The head of the Asterolepis, like the heads of all the other Cœlacanths, and of all the Dipterians, was covered with osseous plates,—its body with osseous scales; and, as I have already had occasion to mention, it is from the star-like tubercles by which the cerebral plates were fretted that M. Eichwald bestowed on the creature its generic name. Agassiz has even erected species on certain varieties in the pattern of the stars, as exhibited on detached fragments; but I am far from being satisfied that we are to seek in their peculiarities of style the characters by which the several species were distinguished. The stellar form of the tubercle seems to have been its normal or most perfect form as it was also, with certain modifications, that of the tubercle of the Coccosteus and Pterichthys; but its development as a complete star was comparatively rare: in most cases the tubercles existed without the rays,—frequently in the insulated pap-like shape, but not rarely confluent, or of an elongated or bent form; and when to these the characteristic rays were added, the stars produced were of a rather eccentric order,—stars somewhat resembling the shadows of stars seen in water. Individual specimens have already been found, on which, if we recognize the form of the tubercle as a specific character, several species might be erected. The accompanying wood-cut (fig. 24) represents, from a Thurso specimen, what seems to be the true normal pattern of these cerebral carvings. Seen in profile (b) the tubercles resemble little hillocks, perforated at their base by single lines of thickly-set caves; while seen from above, (a,) the narrow piers of bone by which the caves are divided take the form of rays. The reader will scarce fail to recognise in this print the coral Monticularia of Lamarck, or to detect, in at least the profile, the peculiarity which suggested the name.

Fig. 25.

SCALES OF ASTEROLEPIS.

(Nat. size.)

a. Inner surface of scale.

b. Exterior surface.

Fig. 26.

PORTION OF CARVED SURFACE OF SCALE.

(Mag. four diameters.)

The scales which covered the creature’s body (fig. 25) were, in proportion to its size, considerably smaller and thinner than those of the Holoptychius, which, however, they greatly resemble in their general style of sculpture. Each, on the lower part of its exposed field, was, we see, fretted by longitudinal anastomosing ridges, which, in the upper part, break into detached angular tubercles, placed with the apex downwards, and hollowed, leaf-like, in the centre; while that covered portion which was overlaid by the scales immediately above we find thickly pitted by microscopic hollows, that give to this part of the field, viewed under a tolerably high magnifying power, a honeycombed appearance. The central and lower parts of the interior surface of the scale (a) are in most of the specimens irregularly roughened; while a broad, smooth band, which runs along the top and sides, and seems to have furnished the line of attachment to the creature’s body, is comparatively smooth. The exterior carvings, though they demand the assistance of the lens to see them aright, are of singular elegance and beauty; as perhaps the accompanying wood-cut, (fig. 26,) which gives a magnified view of a portion of the scale immediately above (b) from the middle of the honeycombed field on the right side, to where the anastomosing ridges bend gracefully in their descent, may in some degree serve to show. I have seen a richly inlaid coat of mail, which was once worn by the puissant Charles the Fifth; but its elaborate carvings, though they belonged to the age of Benvenuto Cellini, were rude and unfinished, compared with those which fretted the armor of the Asterolepis.

Fig. 27.

CRANIAL BUCKLER OF ASTEROLEPIS.

(One fifth nat. size, linear.)

The creature’s cranial buckler, which was of great size and strength, might well be mistaken for the carapace of some Chelonian fish of no inconsiderable bulk. The cranial bucklers of the larger Dipterians were ample enough to have covered the corresponding part in the skulls of our middle-sized market-fish, such as the haddock and whiting; the buckler of a Coccosteus of the extreme size would have covered, if a little altered in shape, the upper surface of the skull of a cod, but the cranial buckler of Asterolepis, from which the accompanying wood-cut was taken, (fig. 27,) would have considerably more than covered the corresponding part in the skull of a large horse; and I have at least one specimen in my collection which would have fully covered the front skull of an elephant. In the smaller specimens, the buckler somewhat resembles a laborer’s shovel divested of its handle, and sorely rust-eaten along its lower or cutting edge. It consisted of plates, connected at the edges by flat squamous sutures, or, as a joiner might perhaps say, glued together in bevelled joints. And in consequence of this arrangement, the same plates which seem broad on the exterior surface appear comparatively narrow on the interior one, and vice versa; the occipital plate, (a,) which, running from the nape along the centre of the buckler, occupies so considerable a space on its outer surface, exhibits inside a superficies reduced at least one half. Like nine tenths of its contemporaries, the Asterolepis exhibits the little central plate between the eyes; but the eye orbits, unlike those of the Coccosteus, and of all the Dipterian genera, which were half-scooped out of the cranial buckler, half-encircled by detached plates, were placed completely within the field of the buckler,—a circumstance in which they resemble the eye orbits of the Pterichthys, and, among existing fish, those of the sea-wolf. The characteristic is also a distinctive one in Cuvier’s second family of the Acanthopterygii,—the “fishes with hard cheeks.” A deep line immediately over the eyes, which, however, indicated no suture, but seems to have been merely ornamental, forms a sort of rudely tatooed eyebrow; the marginal lines parallel to the lateral edges of the buckler were also mere tatooings; but all the others indicated joints which, though more or less anchylosed, had a real existence. So flat was the surface, that the edge of a ruler rests upon it, in my several specimens, both lengthwise and across; but it was traversed by two flat ridges, which, stretching from the corners of the latero-posterior, i. e. parietal, plates, (b, b,) converged at the little plate between the eyes, while along the centre of the depressed angle which they formed, a third ridge, equally flat with the others, ran towards the same point of convergence from the nape. The three ridges, when strongly relieved by a slant light, resemble not inadequately an impression, on a large scale, of the Queen’s broad arrow.

Fig. 28.

INNER SURFACE OF CRANIAL BUCKLER OF ASTEROLEPIS.

(One fifth nat. size, linear.)

The inner surface of the cranial buckler of Asterolepis, (fig. 28,)—that which rested on the cartilaginous box which formed the creature’s interior skull,—stands out in bolder relief from the stone than its outer surface, and forms a more picturesque object. Like the inner surfaces of the bucklers of Coccosteus and Pterichthys, but much more thickly than these, it was traversed by minute channelled markings, somewhat resembling those striæ which may be detected in the flatter bones of the ordinary fishes, and which seem in these to be mere interstices between the osseous fibres. And in the plates, as in the bones, they radiate from the centres of ossification, which are comparatively dense and massy, towards the thinner overlapping edges. These radiating lines are equally well marked in the cerebral bones of the human fœtus. The three converging ridges on the outer surface we find on the inner surface also,—the lateral ones a little bent in the middle, but so directly opposite those outside, that the thickening of the buckler which takes place along their line is at least as much a consequence of their inner as of their outer elevation over the general platform. A fourth bar ran transversely along the nape, and formed the cross beam on which the others rested; for the three longitudinal ridges may be properly regarded as three strong beams, which, extending from the transverse beam at the nape to the front, where they converged like the spokes of a wheel at the nave, gave to the cranial roof a degree of support of which, from its great flatness, it may have stood in need. In cranial bucklers in which the average thickness of the plates does not exceed three eighth parts of an inch, their thickness in the centre of the ridges exceeds three quarters. The head of the largest crocodile of the existing period is defended by an armature greatly less strong than that worn by the Asterolepis of the Lower Old Red Sandstone. Why this ancient Ganoid should have been so ponderously helmed we can but doubtfully guess; we only know, that when nature arms her soldiery, there are assailants to be resisted and a state of war to be maintained. The posterior central plate, the homologue apparently of the occipital bone, was curiously carved into an ornate massive leaf, like one of the larger leaves of a Corinthian capital, and terminated beneath, where the stem should have been, in a strong osseous knob, fashioned like a pike head. Two plates immediately over it, the homologues of the superior frontal bone, with the little nasal plate which, perched atop in the middle, lay between the creature’s eyes, resembled the head and breast in the female figure, at least not less closely than those of the “lady in the lobster;” the posterior frontal plates in which the outer and nether half of the eye orbits were hollowed formed a pair of sweeping wings, and thus in the centre of the buckler we are presented with the figure of an angel, robed and winged, and of which the large sculptured leaf forms the body, traced in a style in no degree more rude than we might expect to see exemplified on the lichen-encrusted shield of some ancient tombstone of that House of Avenel which bore as its arms the effigies of the Spectre Lady. Children have a peculiar knack in detecting such resemblances; and the discovery of the angel in the cranium of the Asterolepis I owe to one of mine.

Fig. 29.

PLATE OF CRANIAL BUCKLER OF ASTEROLEPIS.

It is on this inner side of the cranial buckler, where there are no such pseudo-joinings indicated as on the external surface, that the homologies of the plates of which it is composed can be best traced. It might be well, however, ere setting one’s self to the work of comparison, to examine the skulls of a few of the osseous fishes of our coast, and to mark how very considerably they differ from one another in their lines of suture and their general form. The cerebral divisions of the conger-eel, for instance, are very unlike those of the haddock or whiting; and the sutures in the head of the gurnard are dissimilarly arranged from those in the head of the perch. And after tracing the general type in the more anomalous forms, and finding, with Cuvier, that in even these the “skull consists of the same bones, though much subdivided, as the skulls of the other vertebrata,” we will be the better qualified for grappling with the not greater anomalies which occur in the cranial buckler of the Asterolepis. The occipital plate, A, a, a, (fig. 29,) occupies its ordinary place opposite the centre of the nape; the two parietals, B, B, rest beside it in their usual ichthyic position of displacement; the superior frontal we find existing, as in the young of many animals, in two pieces, C, C; the nasal plate I, placed immediately in advance of it, is flanked, as in the cod, by the anterior frontals, D, D; the posterior frontals, F, F, which, when viewed as in the print, from beneath, seem of considerable size, and describe laterally and posteriorly about one half the eye orbits, have their area on the exterior surface greatly reduced by the overriding squamose sutures of the plates to which they join; and lastly, two of these overlying plates, E, E,—which, occurring in the line of the lateral bar or beam, are of great strength and thickness, and lie for two thirds of their length along the parietals, and for the remaining third along the superior frontals,—represent the mastoid bones. Such, so far as I have been yet able to read the cranial buckler of the Asterolepis, seem to be the homologies of its component plates.

Fig. 30.

PORTION OF UNDER JAW OF ASTEROLEPIS, (OUTER SIDE.)

(One half nat. size.)

Fig. 31.

PORTION OF UNDER JAW OF ASTEROLEPIS, (INNER SIDE.)

(One half nat. size.)

There were no parts of the animal more remarkable than its jaws. The under jaws,—for the nether maxillary consisted, in this fish, as in the placoid fishes, and in the quadrupeds generally, of two pieces joined in the middle,—were, like those of the Holoptychius, boxes of bone, which enclosed central masses of cartilage. The outer and under sides were thickly covered with the characteristic star-like tubercles; and along the upper margin or lip there ran a thickly-set row of small broadly-based teeth, planted as directly on the edge of the exterior plate as iron spikes on the upper edge of a gate (fig. 30.) Mr. Parkinson expresses some wonder, in his work on fossils, that, in a fine ichthyolite in the British Museum, not only the teeth should have been preserved, but also the lips; but we now know enough of the construction of the ancient Ganoids to cease wondering. The lips were formed of as solid bone as the teeth themselves, and had as fair a chance of being preserved entire; just as the metallic rim of a cogged wheel has as fair a chance of being preserved as the metallic cogs that project from it. Immediately behind the front row,—in which the teeth present the ordinary ichthyic appearance,—there ran a thinly-set row of huge reptile teeth, based on an interior platform of bone, which formed the top of the cartilage-enclosing box composing the jaw. These were at once bent outwards and twisted laterally, somewhat like nails that have been drawn out of wood by the claw of a carpenter’s hammer, and bent awry with the wrench, (fig. 31.) They were furrowed longitudinally from point to base by minute thickly-set striæ and were furnished laterally, in most of the specimens though not in all, with two sharp cutting edges. The reptile had as yet no existence in creation; but we see its future coming symbolized in the dentition of this ancient Ganoid: it, as it were, shows us the crocodile lying entrenched behind the fish. The interior structure of these reptile teeth is very remarkable. In the longitudinal section we find numerous cancelli, ranged lengthwise along the outer edges, but much crossed, net-like, within,—greatly more open towards the base than at the point,—and giving place in the centre to a hollow space, occasionally traversed by a few slim osseous partitions. In the transverse section these cancelli are found to radiate from the open centre towards the circumference, like the spokes of a wheel from the nave; and each spoke seems as if, like Aaron’s rod, it had become instinct with vegetative life, and had sprouted into branch and blossom. Seen in a microscope of limited field, that takes in, as in the accompanying print, (fig. 32,) not more than a fourth part of the section, the appearance presented is that of a well-trained wall tree. And hence the generic name Dendrodus, given by Professor Owen to teeth found detached in the deposits of Moray, when the creatures to which they had belonged were still unknown,—a name, however, which will, I suspect, be found synonymous rather with that of a family than of a genus; for so far as I have yet examined, I find that the dendrodic or tree-like tooth, was in at least the Old Red Sandstone, a characteristic of all the Cœlacanth family. I may mention, however, as a curious subject of inquiry, that the Cœlacanths of the Coal Measures seem to have had their reptile teeth formed of pure ivory,—a substance, which I have not yet detected among the reptile-fish of the Old Red. Towards the base of the reptile teeth of Asterolepis, the interstices between the branches greatly widen, as in the branches of a tree in winter divested of its foliage, (fig. 33, c;) the texture also opens towards the base in the fish-teeth, outside, in which, however, the pattern in the transverse section is greatly less complex and ornate than that which the reptile teeth exhibits. When cut across near the point, they appear each as a thick ring, (b,) traversed by lines that radiate towards the centre; when cut across about half way down, they somewhat resemble, seen under a high magnifying power those cast-iron wheels on which the engineer mounts his railway carriages, (a.) In the longitudinal section their line of junction with the jaw is marked by numerous openings, but by no line of division, and they appear as thickly dotted by what were once canaliculi, or life points, as any portion of the dermal bone on which they rest.

Fig. 32.

PORTION OF TRANSVERSE SECTION OF REPTILE TOOTH OF ASTEROLEPIS

a. Nat. size.

b. Mag. twelve diameters.

Fig. 33.

A. Section of Jaw of Asterolepis.

c. Reptile tooth as shown in section.

a, b, & c. Row of ichthyic teeth in dermal plate of jaw.

B. Magnified representatives of ichthyic teeth, a and b, in A.

It seems truly wonderful, when one considers it, to what minute and obscure ramifications that variety of pattern which nature so loves to maintain is found to descend. It descends in the fishes, both recent and extinct, to even the microscopic structure of their teeth; and we find, in consequence, not less variety of figure in the sliced fragments of the teeth of the ichthyolites of a single formation, than in the carved blocks of an extensive calico print-yard. Each species has its own distinct pattern, as if, in all the individuals of which it consisted, the same block had been employed to stamp it; and each genus its own general type of pattern, as if the same radical idea, variously altered and modified, had been wrought upon in all. In the Dendrodic (Cœlacanth?) family, for instance, it is the radical type, that from a central nave there should radiate, spoke-like, a number of arborescent branches; but in the several genera and species of the family, the branches belong, if I may so express myself, to different shrubs, and present dissimilar outlines. It has appeared to me, that at least a presumption against the transmutation of species might be based on those inherent peculiarities of structure which are thus found to pervade the entire texture of the framework of animals. If we find erections differing from one another merely in external form, we have no difficulty in conceiving how, by additions and alterations, they might be brought to exhibit a perfect uniformity of plan and aspect: transmutation,—development,—progression,—(if one may use such terms,)—seem possible in such circumstances. But if the buildings differ from each other, not only in external form, but also in every brick and beam, bolt and nail, no mere scheme of external alteration could ever induce a real resemblance. Every brick would have to be taken down, and every beam and bolt removed. The problem could not be wrought by the remodelling of an old house: the only mode of solving it would be by the erection of a new one.