Ichthyolite Beds of Clune and Lethenbarn—Limestone Quarry—Destruction of Urns and Sarcophagi in the Lime-kiln—Nodules opened—Beautiful coloring of the Remains—Patrick Duff's Description—New Genus of Morayshire Ichthyolite described—Form and size of the Nodules or Stone Coffins—Illustration from Mrs. Marshall's Cements—Forest of Darnaway—The Hill of Berries—Sluie—Elgin—Outliers of the Weald and the Oölite—Description of the Weald at Linksfield—Mr. Duff's Lepidotus minor—Eccentric Types of Fish Scales—Visit to the Sandstones of Scat-Craig—Fine suit of Fossils at Scat-Craig—True graveyard Bones, not mere Impressions—Varieties of pattern—The Diker's "Carved Flowers"—Stagonolepis, a new genus—Termination of the Ramble.
My term of furlough was fast drawing to a close. It was now Wednesday the 14th August, and on Monday the 19th it behooved me to be seated at my desk in Edinburgh. I took boat, and crossed the Moray Frith from Cromarty to Nairn, and then walked on, in a very hot sun, over Shakspeare's Moor to Boghole, with the intention of examining the ichthyolite beds of Clune and Lethenbarn, and afterwards striking across the country to Forres, through the forest of Darnaway, where the forest abuts on the Findhorn, at the picturesque village of Sluie. When I had last crossed the moor, exactly ten years before, it was in a tremendous storm of rain and wind; and the dark platform of heath and bog, with its old ruinous castle standing sentry over it, seemed greatly more worthy of the genius of the dramatist, as cloud after cloud dashed over it, like ocean waves breaking on some low volcanic island, than it did on this clear, breathless afternoon, in the unclouded sunshine. But the sublimity of the moor on which Macbeth met the witches depends in no degree on that of the "heath near Forres," whether seen in foul weather or fair; its topography bears relation to but the mind of Shakspeare; and neither tile-draining nor the plough will ever lessen an inch of its area.
The limestone quarry of Clune has been opened on the edge of an extensive moor, about three miles from the public road, where the province of Moray sweeps upwards from the broad fertile belt of corn-land that borders on the sea, to the brown and shaggy interior. There is an old-fashioned bare-looking farm-house on the one side, surrounded by a few uninclosed patches of corn; and the moorland, here dark with heath, there gray with lichens, stretches away on the other. The quarry itself is merely a piece of moor that has been trenched to the depth of some five or six feet from the surface, and that presents, at the line where the broken ground leans against the ground still unbroken, a low uneven frontage, somewhat resembling that of a ruinous stone-fence. It has been opened in the outcrop of an ichthyolite bed of the Lower Old Red Sandstone, on which in this locality the thin moory soil immediately rests, without the intervention of the common boulder clay of the country; and the fish-enveloping nodules, which are composed in this bed of a rich limestone, have been burnt, for a considerable number of years, for the purposes of the agriculturist and builder. There was a kiln smoking this evening beside the quarry; and a few laborers were engaged with shovel and pickaxe in cutting into the stratified clay of the unbroken ground, and throwing up its spindle-shaped nodules on the bank, as materials for their next burning. Antiquaries have often regretted that the sculptured marble of Greece and Egypt,—classic urns, to whose keeping the ashes of the dead had been consigned, and antique sarcophagi, roughened with hieroglyphics,—should have been so often condemned to the lime-kiln by the illiterate Copt or tasteless Mohammedan; and I could not help experiencing a somewhat similar feeling here. The urns and sarcophagi, many times more ancient than those of Greece and Egypt, and that told still more wondrous stories, lay thickly ranged in this strange catacomb,—so thickly, that there were quite enough for the lime-kiln and the geologists too; but I found the kiln got all, and this at a time when the collector finds scarce any fossils more difficult to procure than those of the Lower Old Red Sandstone. I asked one of the laborers whether he did not preserve some of the better specimens, in the hope of finding an occasional purchaser. Not now, he said: he used to preserve them in the days of Lady Cumming of Altyre; but since her ladyship's death, no one in the neighborhood seemed to care for them, and strangers rarely came the way.
The first nodule I laid open contained a tolerably well-preserved Cheiracanthus; the second, an indifferent specimen of Glyptolepis; and three others, in succession, remains of Coccosteus. Almost every nodule of one especial layer near the top incloses its organism. The coloring is frequently of great beauty. In the Cromarty, as in the Caithness, Orkney, and Gamrie specimens, the animal matter with which the bones were originally charged has been converted into a dark glossy bitumen, and the plates and scales glitter from a ground of opaque gray, like pieces of japan-work suspended against a rough-cast wall. But here, as in the other Morayshire deposits, the plates and scales exist in nearly their original condition, as bone that retains its white color in the centre of the specimens, where its bulk is greatest, and is often beautifully tinged at its thinner edges by the iron with which the stone is impregnated. It is not rare to find some of the better preserved fossils colored in a style that reminds one of the more gaudy fishes of the tropics. We see the body of the ichthyolite, with its finely arranged scales, of a pure snow-white. Along the edges, where the original substance of the bone, combining with the oxide of the matrix, has formed a phosphate of iron, there runs a delicately shaded band of plum-blue; while the out-spread fins, charged still more largely with the oxide, are of a deep red. The description of Mr. Patrick Duff, in his "Geology of Moray," so redolent of the quiet enthusiasm of the true fossil-hunter, especially applies to the ichthyolites of this quarry, and to those of a neighboring opening in the same bed,—the quarry of Lethenbarn. "The nodules," says Mr. Duff, "which in their external shape resemble the stones used in the game of curling, but are elliptical bodies instead of round, lie in the shale on their flat sides, in a line with the dip. When taken out, they remind one of water-worn pebbles, or rather boulders of a shore. A smart blow on the edge splits them along on the major axis, and exposes the interesting inclosure. The practised geologist knows well the thrilling interest attending the breaking up of the nodule: the uninitiated cannot sympathize with it. There is no time when a fossil looks so well as when first exposed. There is a clammy moisture on the surface of the scales or plates, which brings out the beautiful coloring, and adds brilliancy to the enamel. Exposure to the weather soon dims the lustre; and even in a cabinet an old specimen is easily known by its tarnished aspect."
I found at Clune no ichthyolite to which the geologists have not been already introduced, or with which I had not been acquainted previously in the Cromarty beds. The Lower Old Red of Morayshire furnishes, however, at least one genus not yet figured nor described, and of which, so far as I am aware, only a single specimen has yet been found. It seems to have been a small delicately-formed fish; its head covered with plates; its body with round scales of a size intermediate between those of the Osteolepis and Cheiracanthus; its anterior dorsal fin placed, as in the Dipterus, Diplopterus, and Glyptolepis, directly opposite to its ventral fins; the enamelled surfaces of the minute scales were fretted with microscopic undulating ridges, that radiated from the centre to the circumference; similar furrows traversed the occipital plates; and the fins, unfurnished with spines, were formed, as in the Dipterus and Diplopterus, of thick-set, enamelled rays. The posterior fins and tail of the creature were not preserved. I may mention, for the satisfaction of the geologist, that I saw this unique fossil in the possession of the late Lady Cumming of Altyre, a few weeks previous to the lamented death of her ladyship; and that, on assuring her it was as new in relation to the Cromarty and Caithness fish-beds as to those of Moray, she intimated an intention of forthwith sending a drawing of it to Agassiz; but her untimely decease in all probability interfered with the design, and I have not since heard of this new genus of ichthyolite, or of her ladyship's interesting specimen, hitherto apparently its only representative and memorial. In the Morayshire, as in the Cromarty beds, the limestone nodules take very generally the form of the fish which they inclose: they are stone coffins, carefully moulded to express the outline of the corpses within. Is the fish entire?—the nodule is of a spindle form, broader at the head and narrower at the tail. Is it slightly curved, in the attitude of violent death?—the nodule has also its slight curve. Is it bent round, so that the extremities of the creature meet?—the nodule, in conformity with the outline, is circular. Is it disjointed and broken?—the nodule is correspondingly irregular. In nine cases out of ten, the inclosing coffin, like that of an old mummy, conforms to the outline of the organism which it incloses. It is further worthy of remark, too, that a large fish forms generally a large nodule, and a small fish a small one. Here, for instance, is a nodule fifteen inches in length, here a nodule of only three inches, and here a nodule of intermediate size, that measures eight inches. We find that the large nodule contains a Cheirolepis thirteen inches in length, the small one a Diplacanthus of but two and a half inches in length, and the intermediate one a Cheiracanthus of seven inches. The size of the fish evidently regulated that of the nodule. The coffin is generally as good a fit in size as in form; and the bulk of the nodule bears almost always a definite proportion to the amount of animal matter round which it had formed. I was a good deal struck, a few weeks ago, in glancing over a series of experiments conducted for a different purpose by a lady of singular ingenuity,—Mrs. Marshall, the inventor and patentee of the beautiful marble-looking plaster, Intonacco,—to find what seemed a similar principle illustrated in the compositions of her various cements. These are all formed of a basis of lime, mixed in certain proportions with organic matter. The reader must be familiar with cements of this kind long known among the people, and much used in the repairing of broken pottery, such as a cement compounded of quicklime made of oyster shells, mixed up with a glue made of skim-milk cheese, and another cement made also of quicklime mixed up with the whites of eggs. In Mrs. Marshall's cements, the organic matter is variously compounded of both animal and vegetable substances, while the earth generally employed is sulphate of lime; and the result is a close-grained marble-like composition, considerably harder than the sulphate in its original crystalline state. She had deposited, in one set of her experiments, the calcareous earth, mixed up with sand, clay, and other extraneous matters, on some of the commoner molluscs of our shores; and universally found that the mass, incoherent everywhere else, had acquired solidity wherever it had been permeated by the animal matter of the molluscs. Each animal, in proportion to its size, is found to retain, as in the fossiliferous spindles of the Old Red Sandstone, its coherent nodule around it. One point in the natural phenomenon, however, still remains unillustrated by the experiments of Mrs. Marshall. We see in them the animal matter giving solidity to the lime in immediate contact with it; but we do not see it possessing any such affinity for it as to form, in an argillaceous compound, like that of the ichthyolite beds, a centre of attraction powerful enough to draw together the lime diffused throughout the mass. It still remains for the geologic chemist to discover on what principle masses of animal matter should form the attracting nuclei of limestone nodules.
The declining sun warned me that I had lingered rather longer than was prudent among the ichthyolites of Clune; and so, striking in an eastern direction across a flat moor, through which I found the schistose gneiss of the district protruding in masses resembling half-buried boulders, I entered the forest of Darnaway. There was no path, and much underwood, and I enjoyed the luxury of steering my course, out of sight of road and landmark, by the sun, and of being not sure at times whether I had skill enough to play the part of the bush-ranger under his guidance. A sultry day had clarified and cooled down into a clear, balmy evening; the slant beam was falling red on a thousand tall trunks,—here gleaming along some bosky vista, to which the white silky wood-moths, fluttering by scores, and the midge and the mosquito dancing by myriads, imparted a motty gold-dust atmosphere; there penetrating in straggling rays far into some gloomy recess, and resting in patches of flame, amid the darkness, on gnarled stem, or moss-cushioned stump, or gray beard-like lichen. I dislodged, in passing through the underwood, many a tiny tenant of the forest, that had a better right to harbor among its wild raspberries and junipers than I had to disturb them,—velvety night-moths, that had sat with folded wings under the leaves, awaiting the twilight, and that now took short blind flights of some two or three yards, to get out of my way,—and robust, well-conditioned spiders, whose elastic, well-tightened lines snapped sharp before me as I pressed through, and then curled up on the scarce perceptible breeze, like broken strands of wool. But every man, however Whiggish in his inclinations, entertains a secret respect for the powerful; and though I passed within a few feet of a large wasps' nest, suspended to a jutting bough of furze, the wasps I took especial care not to disturb. I pressed on, first through a broad belt of the forest, occupied mainly by melancholy Scotch firs; next through an opening, in which I found an American-looking village of mingled cottages, gardens, fields and wood; and then through another broad forest-belt, in which the ground is more varied with height and hollow than in the first, and in which I found only forest trees, mostly oaks and beeches. I heard the roar of the Findhorn before me, and premised I was soon to reach the river; but whether I should pursue it upwards or downwards, in order to find the ferry at Sluie, was more than I knew. There lay in my track a beautiful hillock, that reclines on the one side to the setting sun, and sinks sheer on the other, in a mural sandstone precipice, into the Findhorn. The trees open over it, giving full access to the free air and the sunshine; and I found it as thickly studded over with berries as if it had been the special care of half a dozen gardeners. The red light fell yet redder on the thickly inlaid cranberries and stone-brambles of the slope, and here and there, though so late in the season, on a patch of wild strawberries; while over all, dark, delicate blueberries, with their flour-bedusted coats, were studded as profusely as if they had been peppered over it by a hailstone cloud. I have seldom seen such a school-boy's paradise, and I was just thinking what a rare discovery I would have deemed it had I made it thirty years sooner, when I heard a whooping in the wood, and four little girls, the eldest scarcely eleven, came bounding up to the hillock, their lips and fingers already dyed purple, and dropped themselves down among the berries with a shout. They were sadly startled to find they had got a companion in so solitary a recess; but I succeeded in convincing them that they were in no manner of danger from him; and on asking whether there was any of them skilful enough to show me the way to Sluie, they told me they all lived there, and were on their way home from school, which they attended at the village in the forest. Hours had elapsed since the master had let them go, but in so fine an evening the berries wouldn't, and so they were still in the wood. I accompanied them to Sluie, and was ferried over the river in a salmon coble. There is no point where the Findhorn, celebrated among our Scotch streams for the beauty of its scenery, is so generally interesting as in the neighborhood of this village; forest and river,—each a paragon in its kind,—uniting for several miles together what is most choice and characteristic in the peculiar features of both. In no locality is the surface of the great forest of Darnaway more undulated, or its trees nobler; and nowhere does the river present a livelier succession of eddying pools and rippling shallows, or fret itself in sweeping on its zig-zag course, now to the one bank, now to the other, against a more picturesque and imposing series of cliffs. But to the geologist the locality possesses an interest peculiar to itself. The precipices on both sides are charged with fossils of the Upper Old Red Sandstone: they form part of a vast indurated graveyard, excavated to the depth of an hundred feet by the ceaseless wear of the stream; and when the waters are low, the teeth-plates and scales of ichthyolites, all of them specifically different from those of Clune and Lethenbarn, and most of them generically so, may be disinterred from the strata in handfuls. But the closing evening left me neither light nor time for the work of exploration. I heard the curfew in the woods from the yet distant town, and dark night had set in long ere I reached Forres. On the following morning I took a seat in one of the south coaches, and got on to Elgin an hour before noon.
Elgin, one of the finest of our northern towns, occupies the centre of a richly fossiliferous district, which wants only better sections to rank it among the most interesting in the kingdom. An undulating platform of Old Red Sandstone, in which we see, largely developed in one locality, the lower formation of the Coccosteus, and in another, still more largely, the upper formation of the Holoptychius Nobilissimus, forms, if I may so speak, the foundation deposit of the district,—the true geologic plane of the country; and, thickly scattered over this plane, we find numerous detached knolls and patches of the Weald and the Oölite, deposited like heaps of travelled soil, or of lime shot down by the agriculturist on the surface of a field. The Old Red platform is mottled by the outliers of a comparatively modern time: the sepulchral mounds of later races, that lived and died during the reptile age of the world, repose on the surface of an ancient burying-ground, charged with remains of the long anterior age of the fish; and over all, as a general covering, rest the red boulder-clay and the vegetable mould. Mr. Duff, in his valuable "Sketch of the Geology of Moray," enumerates five several localities in the neighborhood of Elgin in which there occur outliers of the Weald; though, of course, in a country so flat, and in which the diluvium lies deep, we cannot hold that all have been discovered. And though the outliers of the Oölite have not yet been ascertained to be equally numerous, they seem of greater extent; the isolated masses detached from them by the denuding agencies lie thick over extensive areas; and in working out the course of improvement which has already rendered Elginshire the garden of the north, the ditcher at one time touches on some bed of shale charged with the characteristic Ammonites and Belemnites of the system, and at another on some calcareous sandstone bed, abounding with its Pectens, its Plagiostoma, and its Pinnæ. Some of these outliers, whether Wealden or Oölitic, are externally of great beauty. They occur in the parish of Lhanbryde, about three miles to the east of Elgin, in the form of green pyramidal hillocks, mottled with trees, and at Linksfield, as a confluent group of swelling grassy mounds. And from their insulated character, and the abundance of organisms which they inclose, they serve to remind one of those green pyramids of Central America in which the traveller finds deposited the skeleton remains of extinct races. It has been suggested by Mr. Duff, in his "Sketch,"—a suggestion which the late Sutherlandshire discoveries of Mr. Robertson of Inverugie have tended to confirm,—that the Oölite and Weald of Moray do not, in all probability, represent consecutive formations: they seem to bear the same sort of relation to each other as that mutually borne by the Mountain Limestone and the Coal Measures. The one, of lacustrine or of estuary origin, exhibits chiefly the productions of the land and its fresh waters; the other, as decidedly of marine origin, is charged with the remains of animals whose proper home was the sea. But the productions, though dissimilar, were in all probability contemporary, just as the crabs and periwinkles of the Frith of Forth are contemporary with the frogs and lymnea of Flanders moss.
I had little time for exploration in the neighborhood of Elgin; but that little, through the kindness of my friend Mr. Duff, I was enabled to economize. We first visited together the outlier of the Weald at Linksfield. It may be found rising in the landscape, a short mile below the town, in the form of a green undulating hillock, half cut through by a limestone quarry; and the section thus furnished is of great beauty. The basis on which the hillock rests is formed of the well-marked calcareous band in the Upper Old Red, known as the Cornstone, which we find occurring here, as elsewhere, as a pale concretionary limestone of considerable richness, though in some patches largely mixed with a green argillaceous earth, and in others passing into a siliceous chert. Over the pale-colored base, the section of the hillock is ribbed like an onyx: for about forty feet, bands of gray, green, and blue clays alternate with bands of cream-colored, light-green, and dark-blue limestones; and over all there rests a band of the red boulder-clay, capped by a thin layer of vegetable mould. It is a curious circumstance, well fitted to impress on the geologist the necessity of cautious induction, that the boulder-clay not only overlies, but also underlies, this fresh-water deposit; a bed of unequivocally the same origin and character with that at the top lying intercalated, as if filling up two low flat vaults, between the upper surface of the Cornstone and the lower band of the Weald. It would, however, be as unsafe to infer that this intervening bed is older than the overlying ones, as to infer that the rubbish which chokes up the vaulted dungeon of an old castle is more ancient than the arch that stretches over it. However introduced into the cavity which it occupies,—whether by land-springs or otherwise,—we find it containing fragments of the green and pale limestones that lie above, just as the rubbish of the castle dungeon might be found to contain fragments of the castle itself. When the bed of red boulder-clay was intercalated, the rocks of the overlying Wealden were exactly the same sort of indurated substances that they are now, and were yielding to the operations of some denuding agent. The alternating clays and limestones of this outlier, each of which must have been in turn an upper layer at the bottom of some lake or estuary, are abundantly fossiliferous. In some the fresh-water character of the deposit is well marked: Cyprides are so exceedingly numerous in some of the bands, that they impart to the stone an Oölitic appearance; while others of a dark-colored limestone we see strewed over, like the oozy bottom of a modern lake, with specimens of what seem Paludina, Cyclas, and Planorbus. Some of the other shells are more equivocal: a Mytilus or Modiola, which abounds in some of the bands, may have been either a sea or a fresh-water shell; and a small oyster and Astarte seem decidedly marine. Remains of fish are very abundant,—scales, plates, teeth, ichthyodorulites, and in some instances entire ichthyolites. I saw, in the collection of Mr. Duff, a small but very entire specimen of Lepidotus minor, with the fins spread out on the limestone, as in an anatomical preparation, and almost every plate and scale in its place. Some of his specimens of ichthyodorulites, too, are exceedingly beautiful, and of great size, resembling jaws thickly set with teeth, the apparent teeth being mere knobs ranged along the concave edge of the bone, the surface of which we see gracefully fluted and enamelled. What most struck me, however, in glancing over the drawers of Mr. Duff, was the character of the Ganoid scales of this deposit. The Ganoid order in the days of the Weald was growing old; and two new orders,—the Ctenoid and Cycloid,—were on the eve of taking its place in creation. Hitherto it had comprised at least two-thirds of all the fish that had existed ever since the period in which fish first began; and almost every Ganoid fish had its own peculiar pattern of scale. But it would now seem as if well nigh all the simpler patterns were exhausted, and as if, in order to give the variety which nature loves, forms of the most eccentric types had to be resorted to. With scarce any exception save that furnished by the scales of the Lepidotus minor, which are plain lozenge-shaped plates, thickly japanned, the forms are strangely complex and irregular, easily expressible by the pencil, but beyond the reach of the pen. The remains of reptiles have been found occasionally, though rarely, in this outlier of the Weald,—the vertebra of a Plesiosaurus, the femur of some Chelonian reptile, and a large fluted tooth, supposed Saurian.
I would fain have visited some of the neighboring outliers of the Oölite, but time did not permit. Mr. Duff's collection, however, enabled me to form a tolerably adequate estimate of their organic contents. Viewed in the group, these present nearly the same aspect as the organisms of the Upper Lias of Pabba. There is in the same abundance large Pinnæ, and well-relieved Pectens, both ribbed and smooth; the same abundance, too, of Belemnites and Ammonites of resembling type. Both the Moray outliers and the Pabba deposit have their Terebratulæ, Gervilliæ, Plagiostoma, Cardiadæ, their bright Ganoid scales, and their imperfectly-preserved lignites. They belong apparently to nearly the same period, and must have been formed in nearly similar circumstances,—the one on the western, the other on the eastern coast of a country then covered by the vegetation of the Oölite, and now known, with reference to an antiquity of but yesterday, as the ancient kingdom of Scotland. I saw among the Ammonites of these outliers at least one species, which, I believe, has not yet been found elsewhere, and which has been named, after Mr. Robertson of Inverugie, the gentleman who first discovered it, Ammonites Robertsoni. Like most of the genus to which it belongs, it is an exceedingly beautiful shell, with all its whorls free and gracefully ribbed, and bearing on its back, as its distinguishing specific peculiarity, a triple keel. I spent the evening of this day in visiting, with Mr. Duff, the Upper Old Red Sandstones of Scat-Craig. In Elginshire, as in Fife and elsewhere, the Upper Old Red consists of three grand divisions,—a superior bed of pale yellow sandstone, which furnishes the finest building-stone anywhere found in the north of Scotland,—an intermediate calcareous bed, known technically as the Cornstone,—and an inferior bed of sandstone, chiefly, in this locality, of a grayish-red color, and generally very incoherent in its structure. The three beds, as shown by the fossil contents of the yellow sandstones above, and of the grayish-red sandstones below, are members of the same formation,—a formation which, in Scotland at least, does not possess an organism in common with the Middle Old Red formation; that of the Cephalaspis, as developed in Forfarshire, Stirling, and Ayr, or the Lower Old Red formation; that of the Coccosteus, as developed in Caithness, Cromarty, Inverness, and Banff shires, and in so many different localities in Moray. The Sandstones at Scat-Craig belong to the grayish-red base of the Upper Old Red formation. They lie about five miles south of Elgin, not far distant from where the palæozoic deposits of the coast-side lean against the great primary nucleus of the interior. We pass from the town, through deep rich fields, carefully cultivated and well inclosed: the country, as we advance on the moorlands, becomes more open; the homely cottage takes the place of the neat villa; the brown heath, of the grassy lea; and unfenced patches of corn here and there alternate with plantings of dark sombre firs, in their mediocre youth. At length we near the southern boundary of the landscape,—an undulating moory ridge, partially planted; and see where a deep gap in the outline opens a way to the upland districts of the province, a lively hill-stream descending towards the east through the bed which it has scooped out for itself in a soft red conglomerate. The section we have come to explore lies along its course: it has been the grand excavator in the densely occupied burial-ground over which it flows; but its labors have produced but a shallow scratch after all,—a mere ditch, some ten or twelve feet deep, in a deposit the entire depth of which is supposed greatly to exceed a hundred fathoms. The shallow section, however, has been well wrought; and its suit of fossils is one of the finest, both from the great specific variety which they exhibit, and their excellent state of keeping, that the Upper Old Red Sandstone has anywhere furnished.
So great is the incoherency of the matrix, that we can dig into it with our chisels, unassisted by the hammer. It reminds us of the loose gravelly soil of an ancient graveyard, partially consolidated by a night's frost,—a resemblance still further borne out by the condition and appearance of its organic contents. The numerous bones disseminated throughout the mass do not exist, as in so many of the Upper Old Red Sandstone rocks, as mere films or impressions, but in their original forms, retaining bulk as well as surface: they are true graveyard bones, which may be detached entire from the inclosing mass, and of which, were we sufficiently well acquainted with the anatomy of the long-perished races to which they belonged, entire skeletons might be reconstructed. I succeeded in disinterring, during my short stay, an occipital plate of great beauty, fretted on its outer surface by numerous tubercles, confluent on its anterior part, and surrounded on its posterior portion, where they stand detached, by punctulated markings. I found also a fine scale of Holoptychius Nobilissimus, and a small tooth, bent somewhat like a nail that had been drawn out of its place by two opposite wrenches, and from the internal structure of which Professor Owen has bestowed on the animal to which it belonged the generic name Dendrodus. I have ascertained, however, through the indispensable assistance of Mr. George Sanderson, that the genus Holoptychius of Agassiz, named from a peculiarity in the sculpture of the scale, is the identical genus Dendrodus of Professor Owen, named from a peculiarity in the structure of the teeth. Those teeth of the genus Holoptychius, whether of the Lower or Upper Old Red, that belong to the second or reptile row with which the creature's jaws were furnished, present in the cross section the appearance of numerous branches, like those of trees, radiating from a centre like spokes from the nave of a wheel; and their arborescent aspect suggested to the Professor the name Dendrodus. It seems truly wonderful, when one but considers it, to what minute and obscure ramifications the variety of pattern, specific and generic, which nature so loves to preserve, is found to descend. We see great diversity of mode and style in the architecture of a city built of brick; but while the houses are different, the bricks are always the same. It is not so in nature. The bricks are as dissimilar as the houses. We find, for instance, those differences, specific and generic, that obtain among fishes, both recent and extinct, descending to even the microscopic structure of their teeth. There is more variety of pattern,—in most cases of very elegant pattern,—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; each genus has its own general type of pattern, as if the same inventive idea, variously altered and modified, had been wrought upon in all. In the genus Dendrodus, for instance, it is the generic type, that from a central nave there should radiate, spoke-like, a number of leafy branches; but in the several species, the branches, if I may so express myself, belong to different shrubs, and present dissimilar outlines. There are no repetitions of earlier patterns to be found among the generically different ichthyolites of other formations. We see in the world of fashion old modes of ornament continually reviving: the range of invention seems limited; and we find it revolving, in consequence, in an irregular, ever-returning cycle. But Infinite resource did not need to travel in a circle, and so we find no return or doublings in its course. It has appeared to me, that an argument against the transmutation of species, were any such needed, might be founded on those inherent peculiarities of structure that are ascertained thus to pervade the entire texture of the framework of animals. If we find one building differing from another merely in external form, we have no difficulty in conceiving how, by additions and alterations, they might be made to present a uniform appearance; 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 can induce a real resemblance. Every brick must be taken down, and every beam and belt removed. The problem cannot be wrought by the remodelling of an old house: there is no other mode of solving it save by the erection of a new one.