The Lias of the Hill of Eathie — The Beauty of its Shores — Its Deposits, how formed — Their Animal Organisms indicative of successive Platforms of Existences — The Laws of Generation and of Death — The Triassic System — Its Economic and Geographic Importance — Animal Footprints, but no Fossil Organisms, found in it — The Science of Ichnology originated in this fact — Illustrated by the appearance of the Compensation Pond, near Edinburgh, in 1842 — The Phenomena indicated by the Footprints in the Triassic System — The Triassic and Permian Systems once regarded as one, under the name of the New Red Sandstone — The Coal Measures in Scotland next in order of Succession to the Triassic System — Differences in the Organisms of the two Systems — Extent of the Coal Measures of Scotland — Their Scenic Peculiarities — Ancient Flora of the Carboniferous Period — Its Fauna — Its Reptiles and Reptile Fishes — The other Organisms of the Period — Great Depth of the System — The Processes by which during countless Ages it had been formed.

THE Lias forms, as I have already had occasion to re mark, the base of the great Oolitic system. I dealt in my last address with the productions, vegetable and animal, of those long ages of the world's history which the various deposits of this system represent, and attempted a restoration of some of its more striking scenes, as they must have existed of old in what is now Scotland. But in glancing once more at the Lias, we must pass from the living to the dead, from the vital myriads that once were, to the cemetery that contains their remains. I shall select as my example a single Liassic deposit of Scotland, but in several respects one of the most remarkable, — that of Eathie, on the shores of the Moray Firth, about four miles from the town of Cromarty. And in visiting it in its character as a great burial-ground, — the final resting-place, not only of perished individuals, but also of extinct tribes and races, and in scanning its strangely sculptured monuments, roughened with [154] hieroglyphics, to which living nature furnishes the key, we may perhaps be permitted to indulge in some of those reflections which so naturally suggest themselves in solitary church yards, or among the tombs of the ancient dead.

The hill of Eathie is a picturesque eminence of granitic gneiss, largely mixed with beds of hornblende schist, which extends, in a long precipitous ridge, some five or six hundred feet in height, along the northern side of the Moray Firth, and forms one of a primary chain of hills, which, in their up heaval, uptilted deposits of the Lias and Oolite. The deposit which the hill of Eathie disturbed is exclusively a Liassic one: the upturned edge of the base of the formation rests against the bottom of the hill; and we may trace the edges of its various upper deposits for several hundred feet outwards, bed above bed, until, apparently near the top of the formation, we lose them in the sea. There is a wild beauty on the shores of Eathie. A selvage of comparatively level ground, that occupies the space between the rocky beach and an inflection of the hill, seems embosomed in solitude; the naked scaurs and furze-covered slopes, where the fox and the badger breed, interpose their dizzy fence between it and the inhabited portions of the country above; while the rough unfrequented shore and wide-spreading sea form the secluding barriers below. The only human dwellings visible are the minute specks of white that look out in the sunshine from the dim and diluted blue of the opposite coast; and we may see the lonely firth broadening and widening as it recedes from the eye, and opens to the ocean in a direction so uninterrupted by land, that the waves, which, when the wind blows from the keen north, first begin to break on the distant headlands, and then come running up the coast, like white coursers, may have heaved their first undulating movements under the polar ice. The scene seems such a one as the anchorite might choose to wear out life in, far from the society of fellow-man; and we actually find, in exploring its [155] bosky thickets of wild rose and sloe-thorn, that some anchorite of the olden time did make choice of it. A grey shape less hillock of lichened stone, shaded by luxuriant tufts of fern, still bears the name of the old chapel; and an adjacent spring, on whose overhanging sprays of ivy we may occasionally detect minute tags of linen and woollen cloth, — the offerings of a long-derived superstition, not quite extinct in the district, — is still known as the Saint's Well. But who the anchorite was, tradition has long since forgot; and it was only last year that I succeeded in recovering the name of the saint from an old man, whose father had been a farmer on the land considerably more than a hundred years before. The chapel and spring had been dedicated, he said, to St. Kennat, — a name which we need scarce look for in the Romish Calendar, but which designated, it is probable, one of our old Culdee saints.

The various beds of the Eathie deposit, — all save the lowest, which consists of a blue adhesive clay, — are composed of a dark, finely laminated shale; and, varying in thickness from thirty feet to thirty yards, they are curiously separated from each other by bands of fossiliferous limestone. And so impalpable a substance are these shales, that, when subjected to calcination, which is necessary to extract the bitumen with which they are charged, and which gives them toughness and coherency, they resolve into a powder, used occasionally, from its extreme fineness, in the cleaning of polished brass and copper. They were laid down, it is probable, in circumstances similar to those in which, as described by the late Captain Basil Hall, extensive deposits are now taking place in the Yellow Sea of China. 'At sunset,' says Captain Hall, in the narrative of his voyage to Loo-Choo, 'no land could be perceived from the mast-head, although we were in less than five fathoms water. And before the day broke next morning, the tide had fallen a whole fathom, which brought the ship's bottom within three feet of the [156] ground. It was soon afterwards discovered that she was actually sailing along with her keel in the mud, which was sufficiently indicated by a long yellow train in our wake. Some inconvenience was caused by this extreme shallowness, as it retarded our headway, and affected the steering; but there was in reality not much danger, as it was ascertained, by forcing long poles into the ground, that for many fathoms below the surface on which the sounding lead rested, and from which level the depth of water is estimated, the bottom consisted of nothing but mud formed of an impalpable powder, without the least particle of sand or gravel.' The Liassic deposit of Eathie must have been of slow deposition. It consists of laminæ as thin as sheets of pasteboard, which, of course, shows that there was but little deposited at a time, and pauses between each deposit. And, though a soft muddy surface could have been of itself no proper habitat for the sedentary animals, — serpulæ, oysters, gryphites, and Terebratulæ, — we find further, that they did, notwithstanding, find footing upon it, by attaching themselves to the dead shells of such of the sailing or swimming molluscs, Ammonites and Belemnites, as died over it, and left upon it their remains; from which we infer that the pauses must have been very protracted, seeing that they gave time sufficient for the Terebratuke, — shells that never moved from the place in which they were originally fixed, — to grow up to maturity. The thin leaves of these Liassic volumes must have been slowly formed and deliberately written; for as a series of volumes, reclining against a granite pedestal in the geologic library of nature, I used to find pleasure in regarding them. The limestone bands, curiously marbled with lignite, ichthyolite, and shell, formed the stiff boarding; and the thin pasteboard-like laminæ between, — tens and hundreds of thousands in number in even the slimmer volumes, — composed the closely written leaves. For never did characters or figures lie closer in a page than the organisms on the surfaces [157] of these leaf-like laminæ. Permit me to present you from my note-book with a few readings taken during a single visit from these strange pages.

We insinuate our lever into a fissure of the shale, and turn up a portion of one of the laminæ, whose surface had last seen the light when existing as part of the bottom of the old Liassic sea, when more than half the formation had still to be deposited. Is it not one of the prints of Sower by's Mineral Conchology that has opened up to us? Nay, the shells lie too thickly for that, and there are too many repetitions of organisms of the same species. The drawing, too, is finer, and the shading seems produced rather by such a degree of relief in the figures as may be seen in those of an embossed card, than by any arrangement of lighter and darker colour. And yet the general tone of the colouring, though dimmed by the action of untold centuries, is still very striking. The ground of the tablet is of a deep black, while the colours stand out in various shades, from opaque to silvery white, and from silvery white to deep grey. There, for instance, is a group of large Ammonites, as if drawn in white chalk; there, a cluster of minute bivalves resembling Pectens, each of which bears its thin film of silvery nacre; there, a gracefully formed Lima in deep neutral tint; while, lying athwart the page, like the dark hawthorn leaf in Bewick's well-known vignette, there are two slim sword-shaped leaves coloured in deep umber. We lay open a portion of another page. The centre is occupied by a large Myacites, still bearing a warm tint of yellowish brown, and which must have been an exceedingly brilliant shell in its day; there is a Modiola, a smaller shell, but similar in tint, though not quite so bright, lying a few inches away, with an assemblage of dark grey Gryphites of considerable size on the one side, and on the other a fleet of minute Terebratulæ, that had been borne down and covered up by some fresh deposit from above, when riding at their anchors. We turn [158] over yet another page. It is occupied exclusively by Ammonites of various sizes, but all of one species, as if a whole argosy, old and young, convoyés and convoyed, had been wrecked at once, and sent disabled and dead to the bottom. And here we open yet another page more. It bears a set of extremely slender Belemnites. They lie along and athwart, and in every possible angle, like a heap of boarding-pikes thrown carelessly down on a vessel's deck on the surrender of the crew. Here, too, is an assemblage of bright black plates, that shine like pieces of japan work, the cerebral plates of some fish of the ganoid order; and here an immense accumulation of minute glittering scales of a circular form. We apply the microscope, and find every little interstice in the page covered with organisms. And leaf after leaf for tens and hundreds of feet together, repeats the same strange story. The great Alexandrian library, with its unsummed tomes of ancient literature, the accumulation of long ages, was but a poor and meagre collection, scarce less puny in bulk than recent in date, when compared with this vast and wondrous library of the Scotch Lias.

Now, this Eathie deposit is a crowded burying-ground, greatly more charged with remains of the dead, and more thoroughly saturated with what was once animal matter, than ever yet was city burying-ground in its most unsanitary state. Every limestone band or nodule yields, when struck by the hammer, the heavy fetid odour of corruption and decay; and so charged is the laminated shale with an animal-derived bitumen, that it flames in the fire as if it had been steeped in oil, and yields a carburetted hydrogen gas scarce less abundantly than some of our coals of vegetable origin. The fact of the existence, throughout all the geological ages, of the great law of death, is a fact which must often press upon the geologist. Almost all the materials of his history he derives from cenotaphs and catacombs. He finds no inconsiderable portion of the earth's crust composed [159] of the remains of its ancient inhabitants, — not of dead individuals merely, but also of dead species, dead genera, nay, of even dead creations; and here, where the individual dead lie as thickly on the surface of each of many thousand layers as leaves along the forest glades in autumn, — here, where all the species and many of the genera are dead, nay, where the whole creation represented by its multitudinous organisms is dead, — the great problem which this law of death presents comes upon the explorer in its most palpable and urgent form. The noble verses of James Montgomery, somewhat exaggerative in their character when addressed to a molehill, become as remarkable for their sober propriety as for their beauty when employed here : —

'Tell me, thou dust beneath my feet,
    Thou dust that once hadst breath,—
Tell me how many mortals meet
    In this small hill of death.

By wafting winds and flooding rains,
    From ocean, earth, and sky,
Collected, here the frail remains
    Of slumbering millions lie.

The mole that scoops, with curious toil,
    Her subterranean bed,
Thinks not she ploughs so rich a soil,
    And mines among the dead.

But oh! where'er she turns the ground,
    My kindred earth I see;
Once every atom of this mound
    Lived, breathed, and felt like me.

Like me, these elderborn of clay
    Enjoyed the cheerful light,
Bore the brief burden of a day,
    And went to rest at night.

Methinks this dust yet heaves with breath,
    Ten thousand pulses beat:
Tell me, in this small hill of death
    How many mortals meet.'

It was in mere cobweb toils that those Sadducees who believed 'not in angel, neither in spirit,' endeavoured to entangle our Saviour, when they propounded to him the case of the woman with the seven husbands, and demanded whose wife of the seven she was to be in the Resurrection. But there was a profundity in the reply, which the theologians of nearly two thousand years have, I am disposed to think, failed adequately to comprehend. 'The children of this world marry and are given in marriage,' he said, 'but the children of the Resurrection neither marry nor are given in marriage, neither can they die any more.' Now there seems to be a strictly logical sequence between the two distinct portions of this proposition, — the enunciation that the denizens of the state after death do not marry, and the enunciation that they do not die, which for eighteen centuries there was not science enough in the world adequately to appreciate. The marriage provision was simply a provision tantamount to the original injunction, not of [161] paradise merely, but of every preceding period in which there were organizations of matter possessed by the vital principle: 'Increase and multiply, and replenish the earth.' And all geology presses upon us the conviction, so powerfully enforced by the Liassic deposit at Eathie, that, from the very nature of things, the law of generation and the law of death, wherever space is limited, cannot be dissociated. Each of the multitudinous leaves of the Lias formed in succession an upper surface or platform, on which, for a certain period of time in the world's history, living and sentient creatures pursued the several instincts of their natures, and then ceased to exist. And so immense in many instances was the crowd, that, had the existence of two platforms been restricted to the occupancy of only one platform, they would have lacked footing. A dense crowd of living men may find ample standing-room in an ancient city churchyard, occupying, as they do, a different stratum of space from that occupied by the dead; but were the dead to revive and arise, it would be impossible that the living could find in it the necessary standing-room any longer. They would be jostled from their places far beyond the limits of the enclosing wall. And let us remember, that 'the great globe itself which we inherit' is all one vast burying-ground; nor is it to one stratum that the densely piled remains of its dead are restricted, nor to one hundred, nor to one thousand, nor yet to one hundred thousand strata. Even in this deposit of the Eathie Lias, the successive platforms of the dead may be reckoned up by thousands and tens of thousands; and it would be more possible that a fertile field should have growing upon it at once the harvests of ten thousand succeeding autumns, than that any one of the platforms should have living upon it at once the existences of all the innumerable platforms above and below. The great law 'increase and multiply' gave to each platform its countless crowds; and to make room for the continuous [162] operation of this law, the other great law of death came into action, and so the generations of succeeding periods found space to pursue their various instincts on platforms composed in no small part of the perished generations from which they had sprung. Throughout the whole incalculable past of our planet, — throughout all its unmeasured and unmeasurable periods, — the laws of production and decay have gone inseparably together; they were twin stars on the horizon, tinged by the complementary colours, and so inseparably associated, that the appearance of the one always heralded the rise of the other. And, to my mind at least, it does seem demonstrative of the full-orbed and perfect wisdom of the Divine Master of the Theologians, that He, with that quiet simplicity which Pascal so well designates the characteristic style of Godhead, and with a logic too profound to be appreciated at the time, should have coupled together the twin laws of production and decay, as equally inadmissible into that future state in which the life of man is to be no longer

'Summed up in birthdays and in sepulchres.'

'The children of the resurrection neither marry nor are given in marriage, neither can they die any more.'

From the Oolite, with its Liassic base, we pass on to the Triassic system, — a deposit less characteristically developed in England than on the Continent, but of much economic importance, from those vast beds of rock-salt which, in Britain at least, are exclusively restricted to this system; and of considerable geographic importance, from its great lateral extent. In Scotland¹ it occupies rather more than a hundred square miles of surface, chiefly in Dumfriesshire,

¹ There is good reason to believe that the red rocks overlying the coal of Cumberland, the red sandstones of Corncockle Muir, near Dumfries, the Ayrshire red sandstones, and those of the Isle of Arran, are all of the Permian, not Triassic, epoch. See Siluria, new edition, p. 351. — W.S.S.

[163] along the northern shores of the Solway, and in the line of boundary between the two kingdoms, where it can boast, among its other celebrities, of the famous village of Gretna Green, and the whole of Gretna parish. In England it is chiefly remarkable, in a scenic point of view, for its extreme flatness: its main feature is a want of features. It was, however, at one time notorious for its ponds and marshes, consequents of the impeifect drainage incident to flat low surfaces when of great extent; and in Scotland, though so much more limited in area, it bears this character still. No fossil organisms have yet been found in this deposit in Scotland: it contains, however, in abundance, traces of the ancient inhabitants, even more curiously imprinted on the stone than if they had left in it remains of their framework and is interesting as the field in which, from the sedulous study of these, and undeterred by the scepticism of some of our highest authorities, the late Dr. Duncan of Ruthwell laid the first foundations of that curious and instructive department of geologic science since known as Ichnology. The strange reptiles of this ancient time, in passing over the tide-uncovered beaches of the district, left their footsteps imprinted in the yielding sand; and in this sand, no longer yielding, but hardened long ages ago into solid rock, the footsteps still remain. And with truly wonderful revelations, — revelations of things the most evanescent in themselves, and of incidents regarding which it might seem extravagant to expect that any record should remain, do we find these strange markings charged. They even tell us how the rains of that remote age descended, and how its winds blew.

Let us see whether we cannot indicate a few of at least the simpler principles of this department of science. The artificial sheet of water situated among the Pentlands, and known as the Compensation Pond, was laid dry, during the warm summer of 1842, to the depth of ten fathoms; and as [164] a lake bottom, ten fathoms from the surface, is not often seen, I visited it, in the hope of acquiring a few facts that might be of use to me among the rocks. What first struck me, in surveying the brown sun-baked bottom fiom the shore, was the manner in which it had cracked, in the drying, into irregularly polygonal partings, and that the ripple-markings with which it was fretted extended along only a narrow border, where the water had been shallow enough to permit the winds or superficial currents to act on the soft clay beneath. As I descended, I found the surface between the partings indented with numerous well-marked tracks of the feet of men and animals, made while the clay was yet soft, and now fixed in it by the drying process, like the mark of the stamp in an ancient brick. And some of these tracks were charged with little snatches of incident, which they told in a style remarkably intelligible and clear. At one place, for instance, I found the footprints of some four or five sheep. They struck out towards the middle of the hollow, but turned upwards at a certain point, in an abrupt angle, towards the bank they had quitted, and the marks of increased speed became palpable. The prints, instead of being leisurely set down, so as to make impressions as sharp-edged as if they had been carved or modelled in the clay, were elongated by being thrown out backwards, and the strides were considerably longer than those in the down ward line. And, bearing direct on the retreating footprints from the opposite bank, and also exhibiting signs of haste, I detected the track of a dog. The details of the incident thus recorded in the hardened mud were complete. The sheep had gone down into the hollow shortly after the retreat of the waters, and while it was yet soft; and the dog, either acting upon his own judgment, or on that of the shepherd, had driven them back. A little further on I found the prints of a shoed foot of small size. They passed onwards across the hollow, the steps getting deeper and deeper as [164] they went, until near the middle, where there were a few irregular steps, shorter, deeper, and more broken than any of the others; and then the marks of the small shoes altogether disappeared, and a small naked foot of corresponding size took their place, and formed a long line to the opposite bank. In this case, as in the other, the details of the incident were clear. Some urchin, in venturing across when the mud was yet soft and deep, after wading nearly half the way shod, had deemed it more prudent to wade the rest of it barefoot, than to bemire his stockings. In each case the incident was recorded in peculiar characters; and to read such characters aright, when inscribed upon the rocks, forms part of the proper work of the ichnologist. His key, so far at least as mere incident is concerned, is the key of circumstantial evidence; and very curious events, as I have said, — events which one would scarce expect to find re corded in the strata of ancient systems, — does it at times serve to unlock.
In some remote and misty age, lost in the deep obscurity of the unreckoned eternity that hath passed, but which we have learned to designate as the Triassic period, a strangely formed reptile, unlike anything which now exists, paced slowly across the ripple-marked sands of a lake or estuary.¹ It more resembled a frog or toad than any animal with which we are now acquainted; but to the batrachian peculiarities it added certain crocodilean features, and in size nearly rivalled one of our small Highland oxen. The prints it made very much resembled those of a human hand; but, as in the frog, the hinder paws were fully thrice the size of the fore ones; and there was a gigantic massiveness in the

¹ Reptiles are known to have existed from the period of the Old Red Sandstone, where their tracks have lately been discovered. The reptiles
of the Coal are of the Batrachian type; the Permian reptiles are allied to Batrachians and Monitors; while the reptiles of the Trias are Labyrinthodont. — W. S. S.

[166] fingers and thumb, which those of the human hand never possess. Onward the creature went, slowly and deliberately, on some unknown errand, prompted by its instincts and as the margin of the sea or lake, lately deserted by the water, possessed the necessary plasticity, it retained every impression sharply. The wind was blowing strongly at the time, and the heavens were dark with a gathering shower. On came the rain; the drops were heavy and large; and, beaten aslant by the wind, they penetrated the sand, not perpendicularly, as they would have done had they fallen during a calm, but at a considerable angle. But such was the weight of the reptile, that, though the rain-drops sank deeply into the sand on every side, they made but comparatively faint impressions in its footprints, where the cornpressive effect of its tread rendered the resisting mass more firm. 'We have here, in a single slab,' says Dr. Buckland, in referring, in his address to the Geological Society for 1840, to these very footprints, and their adjuncts, — ' we have here, in a single slab, a combination of proofs as to meteoric, hydrostatic, and locomotive phenomena, which occurred at a time incalculably remote, in the atmosphere, the water, and the movements of animals, from which we infer, with the certainty of cumulative circumstantial evidence, the direction of the wind, the depth and course of the water, and the quarter towards which the animals were passing. The latter is indicated by the direction of the foot steps which form the track; the size and the curvature of the ripple-marks on the sand, now converted into sandstone, show the depth and direction of the current; while the oblique impressions of the rain-drop register the point from which the wind was blowing at or about the time when the animals were passing.'¹ There is another scarce less curi ous

¹ The Labyrinthodon Bucklandi (Lloyd), formerly believed to be a
Triassic reptile, is now ranked as belonging to the Permian fauna. See Ramsay, Quart. Jour. Geol. Soc. vol. ii. p. 198. — W. S. S.

[167] or less minutely recorded incident inscribed on a slab of the same formation, figured and described by Sir Roderick Murchison. It is impressed by the footprints of some be-tailed batrachian, greatly less bulky than the other, that went waddling along much at its leisure, like the sheep in the nursery rhyme, 'trailing its tail behind it.' There is a double track of footprints on the slab, — those of the right and left feet; in the middle between the two, lies the long groove formed by the tail, — a groove continuous, but slightly zig-zagged, to indicate the waddle. The creature, half-way in its course, lay down to rest, having apparently not much to do, and its abdomen formed a slight hollow in the sand beneath. Again rising to its feet, it sprawled a little, and the hinder part of its body, in getting into motion, fretted the portion of the surface that furnished what we may term the fulcrum of the movement, into two wave-like curves. Here, again, are we furnished, from the most remote antiquity, with a piece of narrative of a kind which assuredly we could scarce expect to find enduringly recorded in the rocks. Various reptiles have left curious passages of their history of this kind inscribed on the sandstones of Dumfriesshire; and as Sir William Jardine, the proprietor of some of the quarries, has set himself to the work of illustration, the geologist may soon hope to be put in possession of a monograph at once worthy of the subject and of so distinguished a naturalist.¹ The footprints first observed by Dr. Duncan were chiefly those of tortoises; but there also exist in the rock numerous tracks of the huge batrachians of the period, with traces of a small animal, scarce larger than a rat; and of a nameless, nondescript creature, whose footprints might at the first glance almost be mistaken for those of a horse, but the marks of whose toes have been traced, in some of the impressions, outside the ring of the

¹ See Sir William Jardine's work on the Ichnology of Annandale.

[168] apparent hoof.¹ And this is all we yet know of these reptilian Triassic inhabitants of Scotland. Robinson Crusoe has gone down to the sea-shore, and seen, much to his astonishment, the print of a savage foot in the sand.

According to an old, but not very old, style of nomenclature, derived from mineralogical character not yet wholly obsolete, the two systems, Triassic and Permian, used to be included under one general head, as the New Red Sand stone, or the Bunter Sandstone of Werner and Jameson. And certainly the mere mineralogist might find it no easy matter to draw a line between them. Up to a certain point in the ascending scale there occurs on the Continent strata of a Red Sandstone known as the Lower Bunter; and immediately over it, a Red Sandstone known as the Upper Bunter.² They lie conformably to each other, as if they had been deposited in immediate succession in a still sea: there are no traces of physical convulsion ; — the earthquake and the tornado had slept at the time: there was no devastating inundation of molten fire, nor overwhelming wave of translation, —
 

'It was not in the battle; no tempest gave the shock:'

¹ Chelichnus Titan and Gigas Jardine. — W. S. S.

² The Bunter sandstein and Bunter schiefer; of which the Bunter sandstein is now ranked as lowest, Trias, and the Bunter schiefer as upper, Permian. — W. S. S.

[169] the specific standing of these Belemnites still remains to be determined: it is possible they may not be Secondary forms; and it has been suggested by M. Michelin, a distinguished French geologist, that generically the Belemnite may not be of the premised importance in reference to the age of these Tarentaise beds. 'He is inclined,' we find him saying, 'to consider it an instance of the occurrence of the Belemnite form in the Carboniferous period, rather than of the continuance of the same species of plants through several sucessive epochs.'

But, leaving it to the future researches of geologists to determine whether there be any, and, if so, how many, organisms common to the Secondary and Palæozoic divisions, a very slight acquaintance with fossils is sufficient to show that between the types of organic nature in these two great divisions there exist differences and distinctions of the broadest and most palpable kind. In passing upwards from the Triassic to the Permian, we seem to pass, not merely from one dynasty to another, but, if I may dare employ such a term, from one dispensation to another. So broad are the differences, that they affect whole classes of the animal kingdom. In the class of fishes, for instance, an entire change takes place in the form of the tail. There are a few ichthyic families in the present day, such as the sharks and sturgeons, that have unequally-lobed tails, from the circumstance that a prolongation of the vertebral column runs into the upperlobe; whereas in perhaps nineteen-twentieths of all the existing families, the vertebral column stops short, as in the osseous fishes common at our tables, a little over the lobes, to form for them a medial basis, and the lobes themselves are equal. And this equal-lobed, or, as it is termed, homocercal condition, is the prevailing one, not only in the present time, but in all the Tertiary and in all the Secondary ages, up till the close of the Triassic system. And then, sudden as the shifting of a scene, or as one of the abrupt transitions of a dream, [170] we find, immediately on entering the great Palæozoic division, an entire change. The unequal-lobed or heterocercal tail becomes not only the prevailing, but the only form, save in a few exceptional cases, as in that of the Coccosteus of the Old Red Sandstone, where there were no lobes at all, or as in that of its contemporary the Diplopterus, where the lobes strike out laterally from a prolongation of the column. In short, the equally-lobed tail ceases with the Trias, to re-appear no more, and the unequally-lobed tail takes its place. Similar changes manifest themselves in other divisions and classes of the animal kingdom. Waiving for the present the question raised by the French geologist, M. Michelin, in Britain at least the Belemnite, so abundant in the Secondary formations, and so characteristic of them, has no place among the formations of the Palæozoic period. Save, too, in a few rare and somewhat equivocal species, the equally characteristic Ammonite disappears.¹ We take leave also of the scarce less characteristic Gryphites, of the Trigonia, Plagiostoma, and Perna, with several other well-marked types of shell; but we find their places amply occupied by types exclusively Palæozoic. The Orthoceratites, straight, conical, chambered shells, anticipated, we see, the place of the Belemnites; the Goniatites, that of the Ammanites proper; the Bellerophon and the Euomphalus, unseen in any other period, fall into the general group, and add to the peculiarity of its aspect; with a whole array of unwonted forms among the brachiopoda, such as Spirifers, Producta, Atrypa, and Pentamerus, etc. etc. But it was perhaps in the vegetable world that the Palæozoic ages most remarkably differed from those of the subsequent periods of the geologist, whether Secondary, Tertiary, or Recent. We read in the older poets of enchanted forests; but the true enchanted forests, stranger, in their green luxuriance, than poet ever yet fancied, and where the botanist,

¹ These views require much modification. See Sir Charles Lyell's Supplements, 1857. — W. S. S.

[171] surrounded by irreduceable shapes that would take no place in his systems, might well deem himself in a wild dream, were the forests of the Coal Measures.

The Coal Measures of Scotland occupy about two thousand square miles of surface, and, though much overflown by igneous rock, and occasionally broken through by patches of Old Red Sandstone, run diagonally across the country, from sea to sea, in a tolerably well-defined belt, nearly parallel to the line of the southern flank of the Grampians. Through out their entire extent they owe their scenic peculiarities to the trap; but where least disturbed, as in the Dalkeith coalfield, they are of an inconspicuous, low-featured character, and chiefly remarkable for their rich fields, as to the east of Edinburgh, between the Arthur Seat group of hills and the Carleton hills near Haddington; or for their romantic delIs and soft pastoral valleys, such as Dryden Dell, or the valley of Lasswade, or to enumerate two other well-known representative localities in one stanza, borrowed from Macneil,

'Roslin's gowany braes sae bonny,
Crags and water, woods and glen;
Roslin's banks, unpeer'd by ony,
Save the Muse's, Hawthornden.'

The coal-fields owe some of their more characteristic features, especially in the sister kingdom, to man. The tall chimneys, ever belching out smoke; the thickly-sown engine-houses, with the ever-recurring clank of the engines, and the slow-measured motion of their outstretched arms seen far against the sky; the involved fretwork of railways, connected with some main arterial branch, along which the traveller ever and anon marks the frequent train sweeping by, laden with coals for the distant city; the long flat lines of low cottages, the homes of the poor colliers ; and here and there, where the ironstone bands occur, a group of smelting furnaces; — all serve to mark the Coal Measures, and to distinguish them [172] from every other system. And such — striking off the peculiarities of the trap, which has no necessary connexion with the Carboniferous system, but is common, in some one part of the world or another, to all the systems — are some of the features, natural and superinduced, of this most important, in an economic point of view, of all the geologic formations. They are, as I have said, of no very prominent character. The poet Delta describes, in a fine stanza, the scenery around and to the east of Edinburgh. But though the area which the landscape includes contains one of our most considerable coal-basins, — a basin many square miles in extent, — it does not furnish him with a single descriptive reference. Almost all those bolder and more characteristic features of the scene which his pencil exquisitely touches and relieves, it owes to the igneous rocks:

'Traced in a map the landscape lies,
In cultured beauty stretching wide;
There Pentland's green acclivities;
There ocean with its azure tide;
There Arthur Seat, and, gleaming through
Thy southern wing, Dunedin blue
While in the orient, Lammer's daughters,
A distant giant range, are seen
North Berwick Law with cone of green,
And Bass amid the waters.'

The first perusal of Gulliver's Travels forms an era in the life of a boy, if the work come in his way at the right time; and I was fortunate enough to secure my first reading of it at the mature age of eight years. For weeks, months, years after, my imagination was filled with the little men and little women, and with at least one scene laid in the country of the very tall men, — the scene in which Gulliver, after wandering amid grass that rose twenty feet over his head, lost himself in a vast thicket of barley forty feet high. I became the owner, in fancy, of a colony of little men : I had little men for inhabiting the little houses which I built, for tilling my little apron-breadth of a garden, and for sailing my little ship; and, coupling with the men of Lilliput [174] the scene in Brobdingnag, I often set myself to imagine, when playing truant all alone on the solitary slopes or amid the rocky dells of Drieminorie, how the little creatures, who were sure always to accompany me on these occasions, would be impressed by the surrounding vignette-like scenes and mere picturesque productions, exaggerated on hill and in hollow, by their own minuteness, into great size. I have imagined them threading their way through dark and lofty forests of bracken fifty feet high, or admiring on the hill-side some enormous club-moss, that stretched out its green hairy arms over the soil for whole roods, or arrested at the edge of some dangerous and dreary morass by hedges of gigantic horsetail, that bore atop their many-windowed, club-like cones, twenty feet over the dank surface, and that shot forth at every joint their green verticillate leaves in rings huge as coach-wheels. And while I thus thought, or rather dreamed, for my Lilliputian companions, I became for the time a Lilliputian myself, — saw the minute in nature as if through a magnifying-glass, — roamed in fancy under ferns that had shot up into trees, — and saw the dark cones of the Equisetaceæ stand up over their spiky branches some six yards or so above head. But these day-visions belonged to an early period: dreams of at least a severer, if not more solid cast, dispossessed the little men and women of the place they had occupied; and I had learned to think of the wondrous tale of Swift as one of the most powerful but least genial of all the satires which the errors and perversions of poor human nature have ever provoked, when in the year 1824 I formed my first practical acquaintance with the flora of the Coal Measures. I was engaged as a stone cutter, a few miles from Edinburgh, in making some additions in the old English style to an ancient mansion-house; and the stone in which I wrought, — a curiously variegated sandstone derived from a quarry since shut up, — was, I soon found, exceedingly rich in organic casts and impressions.

[175] They were exclusively vegetable. Often have I detected in the rude block placed before me, to be fashioned into some moulded transom or carved mullion, fragments of a sculpture which I might in vain attempt to rival, — the forked stems of Lepidodendra, fretted into scales that, save for their greater delicacy and beauty, might have reminded the antiquary of the sculptured corslet of scale-armour on the effigies of some ancient knight; the straight-stemmed Calamite, fluted from joint to joint, like the shaft of some miniature column of the Grecian Doric; the Sigillaria, also a fluted column, but of a more meretricious school than that of Greece, for it was richly carved between the flutings; the Stigmaria, fretted over, with its eyelet-holes curiously connected by delicately-waved lines; and occasionally the elaborately ornate Ulodendron, with its rows of circular scars, that seemed to have been subjected to the lathe of an ornamental turner, and its general surface fretted over with what seemed to be nicely sculptured leaves, such as we sometimes see on a Corinthian torus. It was not easy, more than a quarter of a century ago, when Sir Roderick Murchison was still an officer of dragoons, Sir Charles Lyell prosecuting the study of English law, and Dr. Buckland still engaged with his theory of the Flood, which he had given to the world only the previous year, — it was not easy, I say, for a working man to have such questions solved as these fossils of the Coal Measures served to raise. But they were at length in some measure solved. I was taught to look to those forms of the existing flora of our country that most resembled the forms of its flora during the Carboniferous period. And, strange to tell, I found I had just to fall back on my old juvenile imaginings, and to form my first approximate conceptions of the forests of the Coal Measures by learning to look at our ferns, club-mosses, and equisetaceæ, with the eye of some wondering traveller of Lilliput lost amid their entanglements, like Gulliver among those of the [176] fields of Brobdingnag. When sauntering, after the work of the day was over, along the edge of some wood-embosomed streamlet, where the horsetail rose thick and rank in the danker hollows, and the fern shot out its fronds from the drier banks, I had to sink in fancy, as of old, into a mannikin of a few inches, and to see intertropical jungles in the tangled grasses and thickly interlaced equisetaceæ, and tall trees in the herbaceous plants and the shrubs.
But many a wanting feature had to be supplied, and many an existing one altered. Amid forests of arboraceous ferns, tall as our second-class trees, there stood up gigantic club-mosses thicker than the body of a man, and from sixty to eighty feet in height; more than a hundred and fifty species of smaller ferns, and about one-third that number of smaller species of club-mosses, clothed the opener country; and along the frequent marshes and lakes that covered vast tracts of its flat surface, or the sluggish rivers that winded through it, there flouxished huge thickets of equisetaceæ, of from twelve to fourteen different species, tall, some of them, as the masts of pinnaces, and thick and impenetrable as the fairy hedge that surrounded the palace of the Sleeping Beauty. But among these forms of the vegetable world, that, at least through the blue steaming vapour of so dank a land, seem but the more familiar forms of our lochans and hill-sides many times magnified, there arise strange floral shapes, among which we can recognise no existing type. The Ulodendron, bearing along its carved trunk, on two of its sides, rectilinear strips of cones, like rows of buttons on the dress of a boy, and the ornately tatooed Sigillaria, lined longitudinally, and with its thickly-planted vertical rows of leaves bristling from its stem and larger boughs, resemble no vegetable productions which the earth now yields. The landscape, too, has its intertropical forms, — what seem gigantic Cacti, with thickets of canes, and a few species of palms. And, where here and there a flat [177] hillock rises a few yards over the general level, we see groups of noble Araucarians raising their green tops a hundred and fifty feet over the plain. And yet, rich as the flora of the period may seem in individuals, and though it cumbers the soil with a luxuriance witnessed in our own times only among the minuter forms, it is, in all save size and bulk, a poor and low flora after all. The Pines and Araucarians form its only forest-trees. We fail to meet on its plains a single dicotyledonous plant on which a herbivorous mammal could browse. Its Lycopodiaceæ are covered over with catkin-like cones; there are cones on its Ulodendra, cones on its Equisetaceæ, cones on its Araucarians, cones on its Pines; but not a single fruit have we yet found good for the use of man. Nor, after the first impression of novelty has passed away, is there much even to gratify the sight. The marvel of ornately-carved trunks and well-balanced fronds soon palls on the sense; and the prevalence of those spiky rectilinear forms in the scene which Words worth could regard as such deformities in landscape, and which James Grahame so deprecates in his Georgics, 'lies like a load on the weary eye.' Nature labours in the productions of huge immaturities; neither man the monarch, nor his higher subjects the mammals, have yet appeared; and it is all too palpable that that garden has not yet been planted, out of the ground of which there shall grow 'every tree that is pleasant to the sight and good for food.'

Some of the gigantic forms of these primeval forests we can only vaguely and imperfectly illustrate by the dwarf productions of our present moors and morasses; and some of them we fail to connect, by the links of general resemblance, with aught in the vegetable kingdom that now lives. Regarded as a whole, the flora of the Carboniferous age seems as remote in its analogues from that which now exists, as remote in the period during which it flourished.

[178] There are, however, at least two families of plants which bear, not a loose and general, but a minute and thorough resemblance, to families which also existed during the great Secondary and Tertiary periods, and which still continue to occupy a large space among the recent vegetable forms. And these are the Fern and the Pine families. All the species have become extinct over and over again; but the families, and many of the genera, are ever reproduced; and, so far as we know, this earth never possessed a terrestrial flora that had not its ferns and its pines. In all the other divisions and classes of the organic world there are also favourite families, such as the Tortoises among reptiles, the Cestracions among fishes, the Nautilus among Cephalopodes, and the Terebratula among Brachipods. There are few geologic formations in which either the remains or the footprints of tortoises have not been detected; there seems never to have been an ocean that had not its cestracion; the nautilus lived in every age from the times of the Lower Silurian deposits down to the present day ; and, after disinterring specimens of fossil terebratula from our Grauwackes, our Mountain Limestones, our Oolites, and our Chalk Flints, we may cast the drag in the deeper lochs of the Western Highlands, and bring up the living animals, fast anchored by their fleshy cables to stones and shells. We can scarce glance over a group of fossils of the two earlier divisions, the Secondary and the Palæozoic, which we do not find divisible into two classes of types, — the types which still remain, and the types which have disappeared. But why the one set of forms should have been so repeatedly called into being, while the other set was suffered to become obsolete, we cannot so much as surmise. In visiting some old family library that has received no accession to its catalogue for perhaps more than a century, one is interested in marking its more vivacious classes of works, — its Shakespeares, Robinson Crusoes, and Pilgrim's [179] Progresses, — in their first, or at least earlier editions, ranged side by side with obsolete, long-forgotten volumes, their contemporaries, with whose unfamiliar titles we cannot connect a single association. And exactly such is the class of facts with which the geologist is called on to deal: He finds an immense multiplication of editions in the case of some particular type of fish, plant, or shell; and in the case of other types, no after instances of republication, or republication in merely a few restricted instances, and during a limited term. But while it is always easy to say why, in the race of editions, the one class of writings should have been arrested at the starting-post, and the other class should go down to be contemporary with every after production of authorship until the cultivation of letters shall have ceased, the geologist finds himself wholly unable to lay hold of any critical canon through which to determine why, in the organic world, one class of types should be so often republished, and another so peremptorily suppressed. This far, however, we may venture to infer, from finding the two classes under such a marked diversity of dispensation, that creation must have been a result, not of the operation of mere law, which would have dealt after the same fashion with both, but a consequence of the exercise of an elective will; and that as amid immense variety of effort and fertility of invention there are yet certain features of style, and a certain recurrence of words and phrases, that enable us to identify a great author, and to recognise a unity in his works that bespeaks the unity of the producing mind, so ought these connecting links and common features of widely-separated, and in the main dissimilar creations, to teach us the salutary lesson that the Author of all is One, and that, in the exercise of his unrestricted sovereignty and of his infinite wisdom, He chooses and rejects according to his own good pleasure.

From the plants of the swamps and forests of the Coal [180] Measures we pass on to its fauna, terrestrial and aquatic ; — a fauna which, although less picturesque than its wondrous flora, filled with all manner of strange shapes, seems to have borne a corresponding character in uniting great numeric development to a development comparatively limited in classes and orders; and with respect also to the extreme antiqueness of many of its types. The prevailing forms of both flora and fauna belong equally to a fashion that has perished and passed away.

It was held, up till a very recent period, that there had existed no reptiles during the Carboniferous ages. Man has been longer and more perseveringly engaged among the Coal Measures than in any of the other formations; and, long ere geology existed as a science, what used to be termed its figured stones, — plants, shells, and fishes, — were, in consequence, well known to collectors, — a class of people sent into the world to labour instinctively as pioneers in the physical sciences, without knowing why. I have seen prints of some of these figured stones of two centuries' standing, and have succeeded in recognising as old acquaintance the Spirifers and Ferns which had sat for their pictures to artists who knew nothing of either. During the last sixty years there have been many collections made of the Carboniferous fossils, and many coal-fields intelligently examined, but not a trace of the reptile detected. It was not until Sir Charles Lyell's second visit to the United States, five years ago, or rather not until the publication of his second series of travels, three years after, that it was known to European geologists that the coal-fields of Pennsylvania, in the United States, had, like the Trias¹ of the south of Scotland and of the sister kingdom, their Cheirotherium, of, however, not only, as might be anticipated, a different species, but of even a different genus, from that of the newer formation, though not less decidedly

¹ Permians. — W. S. S.

[181] reptilian in its character. And about the same time the remains of a reptile since known as the Archegosaurus were found in a coal-field in Rhenish Bavaria. The Archegosaurus seems to have been a strange-looking creature, — half saurian, half-batrachian, of comparatively small size, with two staring eyes set close together in the middle of a flat triangular skull, and furnished with limbs terminating in distinct toes, but so slim and weak, 'that they could have served,' says Von Meyer, 'only for swimming or creeping.'¹ It is stated in the Lake Superior of Agassiz, that in a shallow expanse of the river into which the lake falls, skirted by flat forest-covered banks, and in which a long series of dreary mud-flats are covered by from a few inches to a few feet of water, there occurs a large gill-furnished salamander (Menobranchus), which the Indians call the 'walking fish,' and which even to them is a great curiosity. It swims wherever there is sufficient depth of water, and creeps over the mud-flats where there is not; and, compared with the swift and powerful Lepidosteus, a reptile-fish of the same stream, it is a stupid, sluggish, inert creature, safe only in its uselessness and the repulsiveness of its appearance. And, judging from the feebleness of its limbs, and the shortness of its ribs, which resemble, says Professor Owen, those of the half-lunged, half-gilled Proteus, such seems to have been the character of the Archegosaurus. Its contemporary, the American Cheirotherium, as shown by its well-defined footprints, must have been a stronger-limbed and larger reptile, — a batrachian heightened by a dash of the crocodile; and, though probably often a dweller in the water, the only vestiges of it which remain show that it must have occasionally stepped out of its river or lake, to take an airing on the banks. Such is nearly the sum-total of our knowledge regarding the reptiles of the Carboniferous

¹ The Archegosauri are related to the Batrachians and Sauroid fishes, according to Owen — Siluria, new edition, p. 363. — W. S. S.

[182] period.¹ Like mammals in the preceding Secondary ages, they formed so inconspicuous a feature of the fauna of the time, that until very recently it escaped notice, and so was not recognised as a feature at all. So far as we yet know, the great Secondary division, in which reptiles, both in size and number, received their fullest development, had but few genera of mammals, — a small pouched animal, and small insectivorous ones: so far as we yet know, the great Palæozoic division, in which fishes, both in size and num ber, received their fullest development, had but its two genera of reptiles, both allied, apparently, to the humble batrachian order. The reigning dynasty of the one period, though the mammal was present, was not that of the mammal, but of the reptile: the reigning dynasty of the other period, though the reptile was present, was not that of the reptile, but of the fish.

The fishes of the Coal Measures, in especial the reptile fishes, were in truth very high types of their class. I have already incidentally said, that with the humble Menobranchus or salamander of the great North American lakes and their tributaries, there is a true reptile fish associated ; — an order of creatures of which, so far as is yet known, there exists in the present creation only a single genus. It would almost seem as if the Lepidosteus had been spared, amid the wreck of genera and species, to serve us as a key by which to unlock the marvels of the ichthyology of those remote periods of geologic history appropriated to the dynasty of the fish.  'This wonderful creature is covered by scales, not of a horny substance, like those of the fish common

¹ Lord Enniskillen possesses a fossil reptile allied to the Cheirotherium from the Yorkshire coal-fields, the Parabatrachus Colei (Owen). A Labyrinthodont reptile, Baphates planiceps (Owen), has been found in the Nova Scotia coal-fields. Also footmarks of sauroid reptiles have been discovered in Scotland by Mr. Hugh Miller, and in the Forest of Dean by Mr. C. Bromby. — W. S. S.

[183] at our tables, but of solid bone, enamelled, like the human teeth, on their outer surfaces. Its own teeth are planted in double rows of unequal size, the larger being of a reptilian, the smaller of an ichthyic character; and the front teeth of the lower jaw are received, as in the alligator, into sheath-like cavities in the upper jaw, — another reptilian trait. Its vertebral column, wholly unlike that of other fishes, each of whose vertebrae consists of a double cup, is formed of vertebrae one end of which consists of a cup and another of a ball, — a characteristic of the snake: it possesses true gills, like all other fishes ; but then it also possesses a peculiar form of cellular airbladder, opening into the throat by a glottis, which, according to Agassiz, our highest authbrity, performs respiratory functions. The Lepidosteus, says Sir Charles Lyell, in describing, in his second series of travels in the United States, an individual which he had seen in sailing across Lake Solitary, leap like a trout or salmon over the surface, in pursuit of its prey, — 'the Lepidosteus, whose hard shining scales are so strong and difficult to pierce that it can scarcely be shot, can live longer out of the water than any other fish of the United States, having a large cellular swimming-bladder, which is said almost to serve the purpose of a real lung.' Further, we find Agassiz stating, in his Lake Superior, that the Lepidosteus is one of the swiftest of fishes, darting like an arrow through the waters, and overcoming with facility even the rapids of the Niagara. He adds further, that when at the latter place, there was a living specimen caught for him, —  the first living specimen he had ever seen; and that 'to his great delight, as well as to his utter astonishment, he saw this fish moving its head upon its neck freely, right and left, and upwards, as a saurian, and as no other fish in creation does.' The true native Yankee has a mode wholly his own, and somewhat redolent of the revolver and the bowie-knife, of describing the peculiar immunities and high standing of [184] the Lepidosteus, or, as he familiarly terms it, the garpike. 'The garpike is,' he says, 'a happy fellow, and beats all fish-creation: he can hurt everything, and nothing can hurt him.' And such is the living type of what was the prevailing and dominant family of the fauna of the Coal Measures.

The great size and marvellous abundance of those reptile fishes of the Carboniferous period may well excite wonder. One ironstone band in the neighbourhood of Gilmerton has furnished by scores, during the last few years, jaws of the Rhizodus Hibberti and its congeners, of a mould so gigantic, that the reptile teeth which they contain are many times more bulky than the teeth of the largest crocodiles. Teeth and scales of the same genus are also abundant among the limestones of Burdiehouse ; — some of the teeth much worn, as if they had belonged to very old individuals; and some of the scales, which were as largely imbricated as those of the haddock or salmon, full five inches in diameter. The broken remains of a Burdiehouse specimen now in the museum of the Royal Society of Edinburgh are supposed by Agassiz to have formed part of one of the largest of true fishes, — a fish which might be appropriately described in the sublime language applied in Job to Leviathan. If the garpike, a fish from three to four feet in length, can make itself so formidable, from its great strength and activity, and the excellence of its armour, that even the cattle and horses that come to drink at the water's side are scarce safe from its attacks, what must have been the character of a fish of the same reptilian order from thirty to forty feet in length, furnished with teeth thrice larger than those of the hugest alligator, and ten times larger than those of the bulkiest Lepidosteus, and that was covered from snout to tail with an impenetrable mail of enamelled bone? 'Canst thou play with Leviathan as with a bird? Canst thou fill his skin with barbed irons, or his head with fish-spears? Who can open the doors of his face? His teeth are terrible [185] round about; his scales are his pride, shut up together as a close seal. In his neck remaineth strength; his heart is as firm as a stone, yea, as hard as a piece of the nether mill stone. The sword of him that layeth at him cannot hold; the spear, the dart, nor the habergeon. He esteemeth iron as straw, and brass as rotten wood.'

In the same waters as the formidable and gigantic Holoptychian genus there lived a smaller but still very formidable reptile fish, now known as the Megalichthys, — a fish whose body was covered with enamelled quadrangular scales, and its head with enamelled plates, both of so exquisite a polish, that they may still be occasionally seen in the shale of a coal-pit, catching the rays of the sun, and reflecting them across the landscape, as is often done by bits of highly glazed earthenware or glass. It was accompanied by another and still smaller, but very handsome, and scarce less highly enamelled, genus of the sauroid class, — the Diplopterus. And if, after the lapse of so many ages, their armour still retains a polish so high, we may be well assured that brightly must it have glittered to the sun when the creatures leaped of old into the air, like the Lepidosteus of Lake Solitary, after some vagrant ephemera or wandering dragon fly; and brightly must the reflected light have flashed into the dark recesses of the old overhanging forest that rose thick and tangled over the lake or river side. The other ichthyic contemporaries of these fishes were very various in size and aspect. About half their number belonged to the same ganoidal or bone-covered order as the Holoptychius and Megalichthys, and the other half to that placoidal order represented in our existing seas by the sharks and rays. The lakes, rivers, and estuaries abounded, perhaps exclusively, in ganoids, such as the Palæoniscus, a small, hand some, well-proportioned genus, containing several species, — the Eurynotus, a rather longer and deeper genus, formed somewhat in the proportions of the modern bream, — and [186] the Acanthodes, an elongated, spined, small-scaled genus, formed in the proportions of the ling or conger eel. On the other hand, the seas of the period, abundant also in ganoids, were tenanted by numerous and obsolete families of sharks, amply furnished both with razorlike teeth in their jaws for cutting, and millstone-like teeth on their palates for crushing, — furnished, some of them, with barbed stings, like the sting-rays, — and whose dorsal fins were armed with elaborately carved spines. The only representative of any of these genera of marine placoids which still exists is the Cestracion or Port-Jackson shark, a placoid of the southern hemisphere.

We know that over the rivers and lakes inhabited by the ganoidal fishes of this period there fluttered several species of insects mounted on gauze wings, like the Ephemeridæ of the present day. At least one of their number must have been of considerable size ; — a single wing preserved in iron stone, though not quite complete, is longer than the anterior wing of one of our largest dragon-flies, and about twice as broad; and, as its longitudinal nervures are crossed at nearly right angles by transverse ones, it must have resembled, when attached to the living animal, a piece of delicate net work. In the woods, and among the decaying trunks, there harboured at the same time several species of snouted beetles, somewhat akin to the diamond beetles of the tropics; and with these, large many-eyed scorpions. The marshes abounded in minute crustaceans, of, however, a low order, that bore their gills attached to their feet, and breathed the more freely the more merrily they danced; and the seas contained the last of the trilobites. I have already referred incidentally to the shells. The fresh waters contained various forms of Unio, somewhat similar to the pearl mussels of our rivers; the profounder depths of the sea had their brachipods, — Spirifers and Producta; while molluscs of a higher order, — Orthoceratites, some of them of gigantic [187] size, Nautilus, and Goniatite, swam above. Corals of strange shapes were abundant : there were several species of Tubilipora, which more resembled the organ-pipe coral than aught else that still exists; with  great numbers of a horn shaped coral, Turbinolia, with its point turned downwards, like that of a Cornucopia, and with an animal somewhat akin to the sea-anemone, expanded, flowerlike, from its upper end. With these, too, there were grouped delicately branched corals, mottled with circular cells; and minutely elegant Fenestrella, that seemed reduced editions of the sea-fan. An antiquely-formed sea-urchin, whose spines were themselves roughened with minute spines, as the more delicate branches of a sweet brier are roughened with thorns, crept slowly among these zoophytes by its many cable-like tentacula; while forests of Crinoidea waved in the tide, and sent abroad their many arms from the ledges overhead. These forests of Crinoidea or stone-lilies formed one of the leading characteristics of the sea-bottoms of the period. We may conceive of them as thickets of flexible-jointed stems rooted to the rocks, and with a variously-formed starfish fixed on the top of each stem. Some of the stems were branched, some simple; in some the petals or rays were richly palmated; in others, plain and starlike; in some, what might be deemed the calyx of the flower, but which was in reality the stomach of the animal, was round and polished; in others, ornately carved into regular geometrical figures. But however various in their appearances, they were all sedentary starfishes, that, poised on their tall, cane like stems, sent abroad their arms into the waters of the old Carboniferous ocean, in quest of food. The minute joints of the stem, perforated in the middle by a circular passage, and fretted by thick-set rays radiating from the centre, seem to have attracted notice in an early age, and are known in legendary lore as the beads of St. Cuthbert. Dr. Mantell states that he has found quantities of these perforated ossicula, [188]  which had been worn as ornaments, in tumuli of the ancient Britons. And you will remember that in  Marmion, the nuns of St. Hilda, who lived in a Liassic country rich in Ammonites, had their stories regarding the snakes which their sainted patroness had changed into stone; and that they were curious to know, in turn, from the nuns of Lindisfarne, who lived in a Carboniferous district, rich in encrinites, the true story of the beads of St. Cuthbert:

'But fain St. Hilda's nuns would learn,
If on a rock by Lindisfarne
St. Cuthbert sits, and toils to frame
The sea-born beads that bear his name.
Such tales had Whitby's fishers told,
And said they might his shape behold,
    And hear his anvil sound.
A deadened clang, a huge dim form,
Seen but and heard, when gathering storm
    And night were closing round.'

The depth of the Carboniferous system has been well described as enormous. Including the Mountain Limestone, which is a marine deposit of the same period, and which must be regarded as forming a member of the Coal Measures, there are districts of England in which, as estimated by Mantell, it has attained to the vast thickness of ten thousand feet. In our own immediate neighbourhood it does not, as estimated by a high authority, Mr. Charles M'Laren, quite equal half that depth. Our Carboniferous system, including the Roslin and Calciferous sandstones, he describes, in his Geology of Fife and the Lot/hians, as about four thousand five hundred feet in thickness, — a thickness, however, which [189] more than equals the height of Ben Nevis over the level of the sea. That coal-basin which extends along the flat richly cultivated plain which stretches from the south-eastern flanks of Arthur Seat to the Garleton Hills in Haddingtonshire, considerably exceeds three thousand feet in depth; and, could it be cleared out to the bottom of the Calciferous sandstones, and divested of the hundred and seventy beds of which it consists, as we have seen the deep hollow of the Compensation Pond divested of its water, it would form by far the profoundest valley in Scotland. Of the beds by which it is occupied, it is estimated that about thirty are coal, varying from several feet to but a few inches in thickness; and we now know, that though some of these coal-seams were formed of drifted plants and trees deposited in the sandy bottom of some great lake or inland sea, by much the greater number are underlaced by bands of an altered vegetable soil, thickly traversed by roots; and that, as in the case of many of our larger mosses, the plants which entered into their composition must have grown and decayed on the spot. And of course, when the plants were growing, the stratum in which they occur, though subsequently buried beneath plummet sound, or at least thousands of feet, must have formed a portion of the surface of the country either altogether subaërial, or, if existing as a swamp, overlaid by but a few inches of water. We have evidence of nearly the same kind in the ripple-markings which are so abundant throughout all the shales and sandstones of the Coal Measures from top to bottom, and which are never formed save where the water is shallow. Stratum after stratum in the whole ten thousand feet included in the system, where it is most largely developed, must have formed in succession the surface either of the dry land or of shallow lakes or seas; one bed must have sunk ere the bed immediately over it could have been deposited; and thus, throughout an extended series of ages, a process must have been taking place on the face of the [190] globe somewhat analogous to that which takes place during a severe frost in those deeper lakes of the country that never freeze, and in which the surface stratum, in consequence of becoming heavier as it becomes colder than the nether strata, is for ever sinking, and thus making way for other strata, that cease to be the surface strata in turn. This sinking process, though persistent in the main, must have been of an intermittent and irregular kind. In some instances, forests seem to have grown on vast platforms, that retained their level unchanged for centuries, nay, thousands of years together: in other cases the submergence seems to have been sudden, and to such a depth, that the sea rushed in and occupied wide areas where the land had previously been, and this to so considerable a depth, and for so extended a period, that the ridges of coral which formed, and the forests of Encrinites which grew, in these suddenly hollowed seas, composed thick beds of marine limestone, which we now find intercalated with coal-seams and lacustrine silts and shales. There seem, too, to have been occasional upward movements on a small scale. The same area which had been occupied first by a forest, and then by a lake or sea, came to be occupied by a forest again; and, though of course mere deposition might have silted up the lake or sea to the level of the water, it is not easy to conceive how, without positive upheaval for at least a few feet, such surfaces at the water-level should have become sufficiently consolidated for the production of gigantic Araucarians and Pines. But the sinking condition was the general one; platform after platform disappeared, as century after century rolled away, impressing upon them their character as they passed; and so the Coal Measures, where deepest and most extensive, consist, from bottom to top, of these buried platforms, ranged like the sheets of a work in the course of printing, that, after being stamped by the pressman, are then placed horizontally over one another in a pile. Another [191] remarkable circumstance, which seems a direct result of the same physical conditions of our planet as those everrecurring subsidences, is the vast horizontal extent and persistency of these platforms. The Appalachian Coal formation in the United States has been traced by Professor Henry Rogers over an area considerably more extensive than that of all Great Britain; and yet there are some of its beds that seem continuous throughout. The great Pittsburg coal-seam of this field, — a seam wonderfully uniform in its thickness, of from eight to twelve feet, — must have once covered a surface of ninety thousand square miles. And this characteristic of persistency, united to great extent, in the various platforms of the Coal Measures, and of ever-recurring subsidence and depression, which accumulated one surface platform over another for hundreds and thousands of feet, belong, I am compelled to hold, to a condition of things no longer witnessed on the face of the globe. The earth has still its morasses, its deltas, its dismal swamps ; it has still, too, its sudden subsidences of surface, by which tracts of forest have been laid under water; but morasses and deltas cover only very limited tracts, and sudden subsidences are at once very exceptional and merely local occurrences. Subsidence during the Carboniferous ages, though interrupted by occasional periods of rest, and occasional paroxysms of upheaval, seems, on the contrary, to have been one of the fixed and calculable processes of nature; and, from apparently the same cause, persistent swamps, and accumulations of vegetable matter, that equalled continents in their extent, formed one of the common and ordinary features of the time.

My subject is one on which great diversity of opinion may and does prevail. But while entertaining a thorough respect for the judgment and the high scientific acquirements of geologists who hold that the earth existed at this early period in the same physical conditions as it does now, I must persist in believing that these conditions were in one important [192] respect essentially different; I must persist in believing that our planet was greatly more plastic and yielding than in these later times ; and that the molten abyss from which all the Plutonic rocks were derived, — that abyss to whose existence the earthquakes of the historic period and the recent volcanoes so significantly testify, — was enveloped by a crust comparatively thin. Like the thin ice of the earlier winter frosts, that yields under the too adventurous skater, it could not support great weights, — table-lands such as now exist, or mountain chains; and hence, apparently, the existence of vast swampy plains nearly level with the sea, and ever-recurring periods of subsidence, wherever a course of deposition had overloaded the surface. The yet further fact, that as we ascend into the middle and earlier Palæozoic periods, the traces of land become less and less frequent, until at length scarce a vestige of a terrestrial plant or animal occurs in entire formations, seems charged with a corroborative evidence. I shall not say that in these primeval periods

'A shoreless ocean tumbled round the globe,'

'A happy rural seat of various view;
Grooves whose rich trees wept
        odorous gums and balm;
Others whose fruits, burnish'd with golden rind,
Hung amiable, Hesperian fables true,
If true, here only, and of delicious taste:
Betwixt them lawns, or level downs, and flocks
Grazing the tender herb, were interposed,
Or palmy hillock; or the flowery lap
Of some irriguous valley spread her store,
Flowers of all hue, and without thorn the rose:
Another side, umbrageous grots and caves
Of cool recess, o'er which the mantling vine
Lays forth her purple grape, and gently creeps
Luxuriant; meanwhile murmuring waters fall
Down the slope hills, dispersed, or in a lake,
That to the fringed bank with myrtle crown'd
Her crystal mirror holds, unite their streams.'