[AN]There still exists some uncertainty regarding the order in which the upper beds occur. Mr. Duff, of Elgin, places the limestone band above the yellow sandstone; Messrs. Sedgwick and Murchison assign it an intermediate position between the red and yellow. The respective places of the gray and red sandstones are also disputed, and by very high authorities; Dr. Fleming holding that the gray sandstones overlie the red, (seeCheek's Edinburgh Journalfor February, 1831,) and Mr. Lyell, that the red sandstones overlie the gray, (seeElements of Geology, first edit., pp. 99-100.) The order adopted above consorts best with the results of the writer's observations, which have, however, been restricted chiefly to the north country. He assigns to the limestone band the middle place assigned to it by Messrs. Sedgwick and Murchison, and to the gray sandstone the inferior position assigned to it by Mr. Lyell; aware, however, that the latter deposit has not only a coping, but also a basement, of red sandstone—the basement forming the upper member of the lower formation.
[AN]There still exists some uncertainty regarding the order in which the upper beds occur. Mr. Duff, of Elgin, places the limestone band above the yellow sandstone; Messrs. Sedgwick and Murchison assign it an intermediate position between the red and yellow. The respective places of the gray and red sandstones are also disputed, and by very high authorities; Dr. Fleming holding that the gray sandstones overlie the red, (seeCheek's Edinburgh Journalfor February, 1831,) and Mr. Lyell, that the red sandstones overlie the gray, (seeElements of Geology, first edit., pp. 99-100.) The order adopted above consorts best with the results of the writer's observations, which have, however, been restricted chiefly to the north country. He assigns to the limestone band the middle place assigned to it by Messrs. Sedgwick and Murchison, and to the gray sandstone the inferior position assigned to it by Mr. Lyell; aware, however, that the latter deposit has not only a coping, but also a basement, of red sandstone—the basement forming the upper member of the lower formation.
The fact seems especially worthy of remark. The organisms of some of the newer formations differ entirely, in widely separated localities, from their contemporary organisms, just as, in the existing state of things, the plants and animals of Great Britain differ from the plants and animals of Lapland or of Sierra Leone. A geologist who has acquainted himself with the belemnites, baculites, turrilites, and sea-urchins of the Cretaceous group in England and the north of France, would discover that he had got into an entirely new field among the hippurites, sphærulites, and nummulites of the same formations, in Greece, Italy, and Spain; nor, in passing the tertiary deposits, would he find less striking dissimilarities between the gigantic, mail-clad megatherium and huge mastodon of the Ohio and the La Plate, and the monsters, their contemporaries, the hairy mammoth of Siberia, and the hippopotamus and rhinoceros of England and the Continent. In the more ancient geological periods, ere the seasons began, the case is essentially different; the contemporary formations, when widely separated, are often very unlike in mineralogical character, but in their fossil contents they are almost always identical. In these earlier ages, the atmospheric temperature seems to have depended more on the internal heat of the earth, only partially cooled down from its original state, than on the earth's configuration or the influence of the sun. Hence a widely spread equality ofclimate—a greenhouse equalization of heat, if I may so speak; and hence, too, it would seem, a widely spread Fauna and Flora. The greenhouses of Scotland and Sweden produce the same plants with the greenhouses of Spain and Italy; and when the world was one vast greenhouse, heated from below, the same families of plants, and the same tribes of animals, seem to have ranged over spaces immensely more extended than those geographical circles in which, in the present time, the same plants are found indigenous, and the same animals native. The fossil remains of the true Coal Measures are the same to the westward of the Alleghany Mountains as in New Holland, India, Southern Africa, the neighborhood of Newcastle, and the vicinity of Edinburgh. And I entertain little doubt that, on a similar principle, the still more ancient organisms of the Old Red Sandstone will be found to bear the same character all over the world.
Fossils of the Upper Old Red Sandstone much more imperfectly preserved than those of the Lower.—The Causes obvious.—Difference between the two Groups, which first strikes the Observer, a Difference in Size.—TheHoloptychiusa characteristic Ichthyolite of the Formation.—Description of its huge Scales.—Of its Occipital Bones, Fins, Teeth, and General Appearance.—Contemporaries of theHoloptychius.—Sponge-like Bodies.—Plates resembling those of the Sturgeon.—Teeth of various Forms, but all evidently the Teeth of Fishes.—Limestone Band, and its probable Origin.—Fossils of the Yellow Sandstone.—ThePterichthysof Dura Den.—Member of a Family peculiarly characteristic of the System.—No intervening Formation between the Old Red Sandstone and the Coal Measures.—TheHoloptychiuscontemporary for a time with theMegalichthys.—The Columns of Tubal Cain.
Thedifferent degrees of entireness in which the geologist finds his organic remains, depend much less on their age than on the nature of the rock in which they occur; and as the arenaceous matrices of the Upper and Middle Old Red Sandstones have been less favorable to the preservation of their peculiar fossils than the calcareous and aluminous matrices of the Lower, we frequently find the older organisms of the system fresh and unbroken, and the more modern existing as mere fragments. A fish thrown into a heap of salt would be found entire after the lapse of many years; a fish thrown into a heap of sand would disappear in a mass of putrefaction in a few weeks; and only the less destructible parts, such as the teeth, the harder bones, and perhaps a few of the scales, would survive. Now, limestone, if I may so speak, is the preserving salt of the geological world; and theconservative qualities of the shales and stratified clays of the Lower Old Red Sandstone are not much inferior to those of lime itself; while, in the Upper Old Red, we have merely beds of consolidated sand, and these, in most instances, rendered less conservative of organic remains than even the common sand of our shores, by a mixture of the red oxide of iron. The older fossils, therefore, like the mummies of Egypt, can be described well nigh as minutely as the existences of the present creation; the newer, like the comparatively modern remains of our churchyards, exist, except in a few rare cases, as mere fragments, and demand powers such as those of a Cuvier or an Agassiz to restore them to their original combinations. But cases, though few and rare, do occur in which, through some favorable accident connected with the death or sepulture of some individual existence of the period, its remains have been preserved almost entire; and one such specimen serves to throw light on whole heaps of the broken remains of its contemporaries. The single elephant, preserved in an iceberg beside the Arctic Ocean, illustrated the peculiarities of the numerous extinct family to which it belonged, whose bones and huge tusks whiten the wastes of Siberia. The human body found in an Irish bog, with the ancient sandals of the country still attached to its feet by thongs, and clothed in a garment of coarse hair, gave evidence that bore generally on the degree of civilization attained by the inhabitants of an entire district in a remote age. In all such instances, the character and appearance of the individual bear on those of the tribe. In attempting to describe the organisms of the Lower Old Red Sandstone, where the fossils lie as thickly in some localities as herrings on our coasts in the fishing season, I felt as if I had whole tribes before me. In describing the fossils of theUpper Old Red Sandstone, I shall have to draw mostly from single specimens. But the evidence may be equally sound so far as it goes.
The difference between the superior and inferior groups of the system which first strikes an observer, is a difference in the size of the fossils of which these groups are composed. The characteristic organisms of the Upper Old Red Sandstone are of much greater bulk than those of the Lower, which seem to have been characterized by a mediocrity of size throughout the entire extent of the formation. The largest ichthyolites of the group do not seem to have much exceeded two feet or two feet and a half in length; its smaller average from an inch to three inches. A jaw in the possession of Dr. Traill—that of an Orkney species ofPlatygnathus, and by much the largest in his collection—does not exceed in bulk the jaw of a full-grown coal-fish or cod; his largestCoccosteusmust have been a considerably smaller fish than an ordinary-sized turbot; the largest ichthyolite found by the writer was aDiplopterus, of, however, smaller dimensions than the ichthyolite to which the jaw in the possession of Dr. Traill must have belonged; the remains of anotherDiplopterusfrom Gamrie, the most massy yet discovered in that locality, seem to have composed the upper parts of an individual about two feet and a half in length. The fish, in short, of the lower ocean of the Old Red Sandstone—and I can speak of it throughout an area which comprises Orkney and Inverness, Cromarty, and Gamrie, and which must have included about ten thousand square miles—ranged in size between the stickleback and the cod; whereas some of the fish of its upper ocean were covered by scales as large as oyster-shells, and armed with teeth that rivalled in bulk those of the crocodile. They must have been fish on an immensely largerscale than those with which the system began. There have been scales of theHoloptychiusfound in Clashbennie which measure three inches in length by two and a half in breadth, and a full eighth part of an inch in thickness. There occur occipital plates of fishes in the same formation in Moray, a full foot in length by half a foot in breadth. The fragment of a tooth still attached to a piece of the jaw, found in the sandstone cliffs that overhang the Findhorn, measures an inch in diameter at the base. A second tooth of the same formation, of a still larger size, disinterred by Mr. Patrick Duff from out the conglomerates of theScat-Craig, near Elgin, and now in his possession, measures two inches in length by rather more than an inch in diameter. (SeePlate X., fig. 4.) There occasionally turn up in the sandstones of Perthshire ichthyodorulites that in bulk and appearance resemble the teeth of a harrow rounded at the edges by a few months' wear, and which must have been attached to fins not inferior in general bulk to the dorsal fin of an ordinary-sized porpoise. In short, the remains of a Patagonian burying-ground would scarcely contrast more strongly with the remains of that battle-field described by Addison, in which the pygmies were annihilated by the cranes, than the organisms of the upper formation of the Old Red Sandstone contrast with those of the lower.[AO]
[AO]I have permitted this paragraph to remain as originally written, though the comparatively recent discovery of a giganticHoloptychius(?) in the Lower Old Red Sandstone of Thurso, by Mr. Robert Dick of that place, (see introductory note,) bears shrewdly against its general line of statement. But it will, at least, serve to show how large an amount of negative evidence may be dissipated by a single positive fact, and to inculcate on the geologist the necessity of cautious induction. An individualHoloptychiusof Thurso must have been at least thrice the size of theHoloptychiusof the Upper Old Red formation, as exhibited in the specimen of Mr. Noble, of St. Madoes.
[AO]I have permitted this paragraph to remain as originally written, though the comparatively recent discovery of a giganticHoloptychius(?) in the Lower Old Red Sandstone of Thurso, by Mr. Robert Dick of that place, (see introductory note,) bears shrewdly against its general line of statement. But it will, at least, serve to show how large an amount of negative evidence may be dissipated by a single positive fact, and to inculcate on the geologist the necessity of cautious induction. An individualHoloptychiusof Thurso must have been at least thrice the size of theHoloptychiusof the Upper Old Red formation, as exhibited in the specimen of Mr. Noble, of St. Madoes.
PLATE X.
PLATE X.
Of this upper formation the most characteristic and most abundant ichthyolite, as has been already said, is theHoloptychius. The large scales and plates, and the huge teeth, belong to this genus. It was first introduced to the notice of geologists in a paper read before the Wernerian Society in May, 1830, by Professor Fleming, and published by him in the February of the following year, inCheek's Edinburgh Journal. Only detached scales and the fragment of a tooth had as yet been found; and these he minutely described as such, without venturing to hazard a conjecture regarding the character or family of the animal to which they had belonged. They were submitted some years after to Agassiz, by whom they were referred, though not without considerable hesitation, to the genusGyrolepis; and the doubts of both naturalists serve to show how very uncertain a guide mere analogy proves to even men of the first order, when brought to bear on organisms of so strange a type as the ichthyolites of the Old Red Sandstone. At this stage, however, an almost entire specimen of the creature was discovered in the sandstones of Clashbennie, by the Rev. James Noble, of St. Madoes, a gentleman who, by devoting his leisure hours to Geology, has extended the knowledge of this upper formation, and whose name has been attached by Agassiz to its characteristic fossil, now designated theHoloptychius nobilissimus. His specimen at once decided that the creature had been noGyrolepis, but the representative of a new genus not less strangely organized, and quite as unlike the existences of the present times as any existence of all the past. So marked are thepeculiarities of theHoloptychius, that they strike the commonest observer.
The scales are very characteristic. They are massy elliptical plates, scarcely less bulky in proportion to their extent of surface than our smaller copper coin, composed internally of bone, and externally of enamel, and presenting on the one side a porous structure, and on the other, when well preserved, a bright, glossy surface. The upper, or glossy side, is the more characteristic of the two. I have placed one of them before me. Imagine an elliptical ivory counter, an inch and a half in length by an inch in breadth, and nearly an eighth part of an inch in thickness, the larger diameter forming a line which, if extended, would pass longitudinally from head to tail through the animal which the scale covered. On the upper or anterior margin of this elliptical counter, imagine a smooth selvedge or border three eighth parts of an inch in breadth. Beneath this border there is an inner border of detached tubercles, and beneath the tubercles large undulating furrows, which stretch longitudinally towards the lower end of the ellipsis. Some of these waved furrows run unbroken and separate to the bottom, some merge into their neighboring furrows at acute angles, some branch out and again unite, like streams which enclose islands, and some break into chains of detached tubercles. (SeePlate X., fig. 3.) No two scales exactly resemble one another in the minuter peculiarities of their sculpture, if I may so speak, just as no two pieces of lake or sea may be roughened after exactly the same pattern during a gale; and yet in general appearance they are all wonderfully alike. Theirstyleof sculpture is the same—a style which has sometimes reminded me of the Runic knots of our ancient north country obelisks. Such was the scale of the creature. The head, which was small,compared with the size of the body, was covered with bony plates, roughened after a pattern somewhat different from that of the scales, being tubercled rather than ridged; but the tubercles present a confluent appearance, just as chains of hills may be described as confluent, the base of one hill running into the base of another. The operculum seems to have been covered by one entire plate—a peculiarity observable, as has been remarked, among some of the ichthyolites of the Lower Old Red Sandstone, such as theDiplopterus,Dipterus, andOsteolepis. And it, too, has its fields of tubercles, and its smooth marginal selvedge, or border, on which the lower edges of the upper occipital plates seem to have rested, just as, in the roof of a slated building, part of the lower tier of slates is overtopped and covered by the tier above. The scales towards the tail suddenly diminish at the ventral fins to about one fourth the size of those on the upper part of the body; the fins themselves are covered at their bases, which seem to have been thick and fleshy like the base of the pectoral fin in the cod or haddock, with scales still more minute; and from the scaly base the rays diverge like the radii of a circle, and terminate in a semicircular outline. The ventrals are placed nearer the tail, says Agassiz, than in any other ganoid fish. (SeePlate X., fig. 2.)
But no such description can communicate an adequate conception to the reader of the strikingly picturesque appearance of theHoloptychius, as shown in Mr. Noble's splendid specimen. There is a general massiveness about the separate portions of the creature, that imparts ideas of the gigantic, independently of its bulk as a whole; just as a building of moderate size, when composed of very ponderous stones, has a more imposing effect than much larger buildings in which the stones are smaller. The body measures a foot across, bytwo feet and a half in length, exclusive of the tail, which is wanting; but the armor in which it is cased might have served a crocodile or alligator of five times the size. It lies on its back, on a mass of red sandstone; and the scales and plates still retain their bony color, slightly tinged with red, like the skeleton of some animal that had lain for years in a bed of ferruginous marl or clay. The outline of the occipital portion of the specimen forms a low Gothic arch, of an intermediate style between the round Saxon and the pointed Norman. This arch is filled by two angular, pane-like plates, separated by a vertical line, that represents, if I may use the figure, the-dividing astragal of the window; and the under jaw, with its two sweeping arcs, or branches, constitutes the frame. All of the head which appears is that under portion of it which extends from the upper part of the belly to the snout. The belly itself is thickly covered by huge carved scales, that, from their massiveness and regular arrangement, remind one of the flags of an ancient stone roof. The carving varies, as they descend towards the tail, being more in the ridged style below, and more in the tubercled style above. So fairly does the creature lie on its back, that the ventral fins have fallen equally, one on each side, and, from their semicircular form, remind one of the two pouch holes in a lady's apron, with their laced flaps. The entire outline of the fossil is that of an elongated ellipsis, or rather spindle, a little drawn out towards the caudal extremity. The places of all the fins are not indicated, but, as shown by other specimens, they seem to have been crowded together towards the lower extremity, like those of theGlyptolepis, an ichthyolite which, in more than one respect, theHoloptychiusmust have resembled, and which, from this peculiarity, presents a brush-like appearance—the head and shoulders representing thehandle, and the large and thickly clustered fins the spreading bristles.[AP]
[AP]There are now six species ofHoloptychiusenumerated—H. Andersoni,H. Flemingii,H. giganteus,H. Murchisoni,H. nobilissimus, andH. Omaliusii.
[AP]There are now six species ofHoloptychiusenumerated—H. Andersoni,H. Flemingii,H. giganteus,H. Murchisoni,H. nobilissimus, andH. Omaliusii.
Some of the occipital bones of theHoloptychiusare very curious and very puzzling. There are pieces rounded at one of the ends, somewhat in the manner of the neck joints of our better known quadrupeds, and which have been mistaken for vertebræ; but which present evidently, at the apparent joint, the enamel peculiar to the outer surface of all the plates and scales of the creature, and which belonged, it is probable, to the snout. There are saddle-shaped bones, too, which have been regarded as the central occipital plates of a new species ofCoccosteus, but whose style of confluent tubercle belongs evidently to theHoloptychius. The jaws are exceedingly curious. They are composed of as solid bone as we usually find in the jaws of mammalia; and the outer surface, which is covered in animals of commoner structure with portions of the facial integuments, we find polished and japanned, and fretted into tubercles. The jaws of the creature, like those of theOsteolepisof the lower formation, were naked jaws; it is, indeed, more than probable that all its real bones were so, and that the internal skeleton was cartilaginous. A row of thickly-set, pointed teeth ran along the japanned edges of the mouth—what, in fish of the ordinary construction, would be the lips; and inside this row there was a second and widely-set row of at least twenty times the bulk of the other, and which stood up over and beyond it, like spires in a city over the rows of lower buildings in front. A nearly similar disposition of teeth seems also to have characterized theHoloptychiusof the Coal Measures, but the contrast in size was somewhat less marked. One of the most singularly-formed bones of the formation will be found, I doubt not, when perfect specimens of the upper part of the creature shall be procured, to have belonged to theHoloptychius. It is a huge ichthyodorulite, formed, box-like, of four nearly rectangular planes, terminating in a point, and ornamented on two of the sides by what, in a work of art, the reader would at once term a species of Chinese fretwork. Along the centre there runs a line of lozenges, slightly truncated where they unite, just as, in plants that exhibit the cellular texture, the lozenge-shaped cells may be said to be truncated. At the sides of the central line, there run lines of half lozenges, which occupy the space to the edges. Each lozenge is marked by lines parallel to the lines which describe it, somewhat in the manner of the plates of the tortoise. The centre of each is thickly tubercled; and what seems to have been the anterior plane of the ichthyodorulite is thickly tubercled also, both in the style of the occipital plates and jaws of theHoloptychius. This curious bone, which seems to have been either hollow inside, or, what is more probable, filled with cartilage, measures, in some of the larger specimens, an inch and a half across at the base on its broader planes, and rather more than half an inch on its two narrower ones.[AQ]
[AQ]This bone has been since assigned by Agassiz to a new genus, of which no other fragments have yet been found, but which has been named provisionallyPlacothorax paradoxus.
[AQ]This bone has been since assigned by Agassiz to a new genus, of which no other fragments have yet been found, but which has been named provisionallyPlacothorax paradoxus.
Geologists have still a great deal to learn regarding the contemporaries of theHoloptychius nobilissimus. The lower portion of that upper formation to which it moreespecially belongs—the portion represented in our second pyramid by the conglomerate and sandstone bar—though unfavorable to the preservation of animal remains, represents assuredly no barren period. It has been found to contain bodies apparently organic, that vary in shape like the sponges of our existing seas, which in general appearance they somewhat resemble, but whose class, and even kingdom, are yet to fix.[AR]
[AR]These organisms, if in reality such, are at once very curious and very puzzling. They occur in some localities in great abundance. A piece of Clashbennie flagstone, somewhat more than two feet in length, by fifteen inches in breadth, kindly sent me for examination by the Rev. Mr. Noble, of St. Madoes, bears no fewer than twelve of them on its upper surface, and presents the appearance of a piece of rude sculpture, not very unlike those we sometimes see in country churchyards, on the tombstones of the times of the Revolution. All the twelve vary in appearance. Some of them are of a pear shape—some are irregularly oval—some resemble short cuts of the bole of a tree—some are spread out like ancient manuscripts, partially unrolled—one of the number seems a huge, though not over neatly formed acorn, an apprentice mason's first attempt—the others are of a shape so irregular as to set comparison and description at defiance. They almost all agree, however, when cut transversely, in presenting flat, elliptical arcs as their sectional lines—in having an upper surface comparatively smooth, and an under surface nearly parallel to it, thickly corrugated—and in being all coated with a greasy, shining clay, of a deeper red than the surrounding stone. I was perhaps rather more confident of their organic character after I had examined a few merely detached specimens, than now that I have seen a dozen of them together. It seems at least a circumstance to awaken doubt, that though they occur in various positions on the slab—some extending across it, some lying diagonally, some running lengthwise—the corrugations of their under surfaces should run lengthwise in all—furrowing them in every possible angle, and giving evidence, not apparently to the influences of an organic law, internal to each, but of the operation of some external cause, acting on the whole in one direction.
[AR]These organisms, if in reality such, are at once very curious and very puzzling. They occur in some localities in great abundance. A piece of Clashbennie flagstone, somewhat more than two feet in length, by fifteen inches in breadth, kindly sent me for examination by the Rev. Mr. Noble, of St. Madoes, bears no fewer than twelve of them on its upper surface, and presents the appearance of a piece of rude sculpture, not very unlike those we sometimes see in country churchyards, on the tombstones of the times of the Revolution. All the twelve vary in appearance. Some of them are of a pear shape—some are irregularly oval—some resemble short cuts of the bole of a tree—some are spread out like ancient manuscripts, partially unrolled—one of the number seems a huge, though not over neatly formed acorn, an apprentice mason's first attempt—the others are of a shape so irregular as to set comparison and description at defiance. They almost all agree, however, when cut transversely, in presenting flat, elliptical arcs as their sectional lines—in having an upper surface comparatively smooth, and an under surface nearly parallel to it, thickly corrugated—and in being all coated with a greasy, shining clay, of a deeper red than the surrounding stone. I was perhaps rather more confident of their organic character after I had examined a few merely detached specimens, than now that I have seen a dozen of them together. It seems at least a circumstance to awaken doubt, that though they occur in various positions on the slab—some extending across it, some lying diagonally, some running lengthwise—the corrugations of their under surfaces should run lengthwise in all—furrowing them in every possible angle, and giving evidence, not apparently to the influences of an organic law, internal to each, but of the operation of some external cause, acting on the whole in one direction.
It contains, besides, in considerable abundance, though in a state of very imperfect preservation, scales that differ from those of theHoloptychius, and from one another. One of these, figured and described by Professor Fleming inCheek's Edinburgh Journal, bearing on its upper surface a mark like a St. Andrew's cross, surrounded by tubercled dottings, and closely resembling in external appearance some of the scales of the common sturgeon, "may be referred with some probability," says the Professor, "to an extinct species of the genusAccipenser."[AS]
[AS]May I crave the attention of the reader to a brief statement of fact? I have said that Professor Fleming, when he minutely described the scales of theHoloptychius, hazarded no conjecture regarding the generic character of the creature to which they had belonged; he merely introduced them to the notice of the public as the scales of some "vertebrated animal, probably those of a fish." I now state that he described the scales of a contemporary ichthyolite as bearing, in external appearance, a "close resemblance to some of the scales of the common sturgeon." It has been asserted, that it was the scales of theHoloptychiuswhich he thus described, "referring them to an extinct species of the genusAccipenser;" and the assertion has been extensively credited, and by some of our highest geological authorities. Agassiz himself, evidently in the belief that the professor had fallen into a palpable error, deems it necessary to prove that theHoloptychiuscould have borne "no relation to theAccipenseror sturgeon." Mr. Murchison, in hisSilurian System, refers also to the supposed mistake. The person with whom the misunderstanding seems to have originated is the Rev. Dr. Anderson, of Newburgh. About a twelvemonth after the discovery of Professor Fleming in the sandstones of Drumdryan, a similar discovery was made in the sandstones of Clashbennie by a geologist of Perth, who, on submitting his new found scales to Dr. Anderson, concluded, with the Doctor, that they could be no other than oyster shells; though eventually, on becoming acquainted with the decision of Professor Fleming regarding them, both gentlemen were content to alter their opinion, and to regard them as scales. The Professor, in his paper on the Old Red Sandstone inCheek's Journal, referred incidentally to theoyster shellsof Clashbennie—a somewhat delicate subject of allusion; and in Dr. Anderson's paper on the same formation, which appeared about seven years after, in the New Journal of Professor Jameson, the geological world was told, for the first time, that Professor Fleming had described a scale of Clashbenniesimilar to those of Drumdryan, (i. e., those of theHoloptychius,) as bearing a "close resemblance to some of the scales on the common sturgeon," and as probably referable to some "extinct species of the genusAccipenser." Now, Professor Fleming, instead of stating that the scales were at all similar, had stated very pointedly that they were entirely different; and not only had he described them as different, but he had alsofiguredthem as different, and had placed the figures side by side, that the difference might be the better seen. To the paper of the Professor, which contained this statement, and to which these figures were attached, Dr. Anderson referred, as "read before the Wernerian Society;"—he quoted from it in the Professor's words—he drew some of the more important facts of his own paper from it—in his late Essay on the Geology of Fife he has availed himself of it still more largely, though with no acknowledgment; it has constituted, in short, by far the most valuable of all his discoveries in connection with the Old Red Sandstone, and apparently the most minutely examined; and yet, so completely did he fail to detect Professor Fleming's carefully drawn distinction between the scales of theHoloptychiusand those of its contemporary, that when Agassiz, misled apparently by the Doctor's own statement, had set himself to show that the scaly giant of the formation could have been no sturgeon, the Doctor had the passage in which the naturalist established the fact transferred into a Fife newspaper, with, of course, the laudable intention of preventing the Fife public from falling into theabsurd mistakeof Professor Fleming. There seems to be something rather inexplicable in all this; but there can be little doubt Dr. Anderson could satisfactorily explain the whole matter without once referring to theoyster shellsof Clashbennie. It is improbable that he could have wished or intended to injure the reputation of a gentleman to whose freely-imparted instructions he is indebted for much the greater portion of his geological skill—whose remarks, written and spoken, he has so extensively appropriated in his several papers and essays—and whose character is known far beyond the limits of his country, for untiring research, philosophic discrimination, and all the qualities which constitute a naturalist of the highest order. Dr. Johnston, of Berwick, in hisHistory of British Zoöphytes, (a work of an eminently scientific character,) justly "ascribes to the labors and writings" of Professor Fleming "no small share in diffusing that taste for Natural History which is now abroad." And as an interesting corroboration of the fact, I may state, that Dr. Malcolmson, of Madras, lately found an elegant Italian translation ofFleming's Philosophy of Zoölogy, high in repute among the elite of Rome. Lest it should be supposed I do Dr. Anderson injustice in these remarks, I subjoin the grounds of them in the following extracts from professor Fleming's paper inCheek's Journal, and from the paper inJameson's New Edinburgh Journal, in which the Doctor purports to give a digest of the former, without once referring, however, to the periodical in which it is to be found:—"In the summer of 1827," says Dr. Fleming, "I obtained from Drumdryan quarry, to the south of Cupar, situate in the higher strata of yellow sandstone, certain organisms, which I readily referred to the scales of vertebrated animals, probably those of a fish. The largest (seePlate II., fig. 1, 'figure of a scale of the Holoptychius') was one inch and one tenth in length, about one inch and two tenths in breadth, and not exceeding the fiftieth of an inch in thickness. The part which, when in its natural position, had been imbedded in the cuticle, is comparatively smooth, exhibiting, however, in a very distinct manner, the semicircularly parallel layers of growth with obsolete diverging striæ, giving to the surface, when under a lens, a reticulated aspect. The part naturally exposed is marked with longitudinal, waved, rounded, anastomosing ridges, which are smooth and glossy. The whole of the inside of the scale is smooth, though exhibiting with tolerable distinctness the layers of growth. The form and structure of the object indicated plainly enough that it had been a scale, a conclusion confirmed by the detection of the phosphate of lime in its composition. At this period I inserted a short notice of the occurrence of these scales in our provincial newspaper, theFife Herald, for the purpose of attracting the attention of the workmen and others in the neighborhood, in order to secure the preservation of any other specimens which might occur."Nearly a year after these scales had been discovered, not only in the upper, but even in some of the lower beds of the Yellow Sandstone, I was informed thatoyster shellshad been found in a quarry in the Old Red Sandstone at Clashbennie, near Errol, in Perthshire, and that specimens were in the possession of a gentleman in Perth. Interested in the intelligence, I lost no time in visiting Perth, and was gratified to find that the supposed oyster shells were, in fact, similar to those which I had ascertained to occur in a higher part of the series. The scales were, however, of a larger size, some of them exceeding three inches in length, and one eighth of an inch in thickness. Upon my visit to the quarry, I found the scales, as in the Yellow Sandstone, most abundant in those parts of the rock which exhibited a brecciated aspect. Many patches a foot in length, full of scales, have occurred; but as yet no entire impression of a fish has been obtained."Another scale,differing from those already noticed, (seePlate II., fig. 3, 'figure of an oblong tubercle plate traversed diagonally by lines, which, bisecting one another a little above the centre, resembles a St. Andrew's cross, and marked on the edges by faintly radiating lines,') is about an inch and a quarter in length, and an inch in breadth. In external appearance it bears a very close resemblance to some of the scales on the common sturgeon, and may, with some probability, be referred to an extinct species of the genusAccipenser."—(Cheek's Edinburgh Journal, Feb. 1831, p. 85.)"Dr. Fleming, in 1830," says Dr. Anderson, "read before the Wernerian Society a notice 'on the occurrence of scales of vertebrated animals in the Old Red Sandstone of Fifeshire.' These organisms, as described by him, occurred in the Yellow Sandstone of Drumdryan and the Gray Sandstone of Parkhill. From the former locality scales of a fish were obtained.... The same paper (Professor Fleming's) contains a notice ofsimilar scalesin the Old Red Sandstone of Clashbennie, near Errol, in Perthshire, one of which is described as bearing 'a very close resemblance to some of the scales on the common sturgeon, and may with some probability be referred to an extinct species of the genusAccipenser.'"—(Professor Jameson's Edin. New Phil. Journal, Oct. 1837, p. 138.)
[AS]May I crave the attention of the reader to a brief statement of fact? I have said that Professor Fleming, when he minutely described the scales of theHoloptychius, hazarded no conjecture regarding the generic character of the creature to which they had belonged; he merely introduced them to the notice of the public as the scales of some "vertebrated animal, probably those of a fish." I now state that he described the scales of a contemporary ichthyolite as bearing, in external appearance, a "close resemblance to some of the scales of the common sturgeon." It has been asserted, that it was the scales of theHoloptychiuswhich he thus described, "referring them to an extinct species of the genusAccipenser;" and the assertion has been extensively credited, and by some of our highest geological authorities. Agassiz himself, evidently in the belief that the professor had fallen into a palpable error, deems it necessary to prove that theHoloptychiuscould have borne "no relation to theAccipenseror sturgeon." Mr. Murchison, in hisSilurian System, refers also to the supposed mistake. The person with whom the misunderstanding seems to have originated is the Rev. Dr. Anderson, of Newburgh. About a twelvemonth after the discovery of Professor Fleming in the sandstones of Drumdryan, a similar discovery was made in the sandstones of Clashbennie by a geologist of Perth, who, on submitting his new found scales to Dr. Anderson, concluded, with the Doctor, that they could be no other than oyster shells; though eventually, on becoming acquainted with the decision of Professor Fleming regarding them, both gentlemen were content to alter their opinion, and to regard them as scales. The Professor, in his paper on the Old Red Sandstone inCheek's Journal, referred incidentally to theoyster shellsof Clashbennie—a somewhat delicate subject of allusion; and in Dr. Anderson's paper on the same formation, which appeared about seven years after, in the New Journal of Professor Jameson, the geological world was told, for the first time, that Professor Fleming had described a scale of Clashbenniesimilar to those of Drumdryan, (i. e., those of theHoloptychius,) as bearing a "close resemblance to some of the scales on the common sturgeon," and as probably referable to some "extinct species of the genusAccipenser." Now, Professor Fleming, instead of stating that the scales were at all similar, had stated very pointedly that they were entirely different; and not only had he described them as different, but he had alsofiguredthem as different, and had placed the figures side by side, that the difference might be the better seen. To the paper of the Professor, which contained this statement, and to which these figures were attached, Dr. Anderson referred, as "read before the Wernerian Society;"—he quoted from it in the Professor's words—he drew some of the more important facts of his own paper from it—in his late Essay on the Geology of Fife he has availed himself of it still more largely, though with no acknowledgment; it has constituted, in short, by far the most valuable of all his discoveries in connection with the Old Red Sandstone, and apparently the most minutely examined; and yet, so completely did he fail to detect Professor Fleming's carefully drawn distinction between the scales of theHoloptychiusand those of its contemporary, that when Agassiz, misled apparently by the Doctor's own statement, had set himself to show that the scaly giant of the formation could have been no sturgeon, the Doctor had the passage in which the naturalist established the fact transferred into a Fife newspaper, with, of course, the laudable intention of preventing the Fife public from falling into theabsurd mistakeof Professor Fleming. There seems to be something rather inexplicable in all this; but there can be little doubt Dr. Anderson could satisfactorily explain the whole matter without once referring to theoyster shellsof Clashbennie. It is improbable that he could have wished or intended to injure the reputation of a gentleman to whose freely-imparted instructions he is indebted for much the greater portion of his geological skill—whose remarks, written and spoken, he has so extensively appropriated in his several papers and essays—and whose character is known far beyond the limits of his country, for untiring research, philosophic discrimination, and all the qualities which constitute a naturalist of the highest order. Dr. Johnston, of Berwick, in hisHistory of British Zoöphytes, (a work of an eminently scientific character,) justly "ascribes to the labors and writings" of Professor Fleming "no small share in diffusing that taste for Natural History which is now abroad." And as an interesting corroboration of the fact, I may state, that Dr. Malcolmson, of Madras, lately found an elegant Italian translation ofFleming's Philosophy of Zoölogy, high in repute among the elite of Rome. Lest it should be supposed I do Dr. Anderson injustice in these remarks, I subjoin the grounds of them in the following extracts from professor Fleming's paper inCheek's Journal, and from the paper inJameson's New Edinburgh Journal, in which the Doctor purports to give a digest of the former, without once referring, however, to the periodical in which it is to be found:—
"In the summer of 1827," says Dr. Fleming, "I obtained from Drumdryan quarry, to the south of Cupar, situate in the higher strata of yellow sandstone, certain organisms, which I readily referred to the scales of vertebrated animals, probably those of a fish. The largest (seePlate II., fig. 1, 'figure of a scale of the Holoptychius') was one inch and one tenth in length, about one inch and two tenths in breadth, and not exceeding the fiftieth of an inch in thickness. The part which, when in its natural position, had been imbedded in the cuticle, is comparatively smooth, exhibiting, however, in a very distinct manner, the semicircularly parallel layers of growth with obsolete diverging striæ, giving to the surface, when under a lens, a reticulated aspect. The part naturally exposed is marked with longitudinal, waved, rounded, anastomosing ridges, which are smooth and glossy. The whole of the inside of the scale is smooth, though exhibiting with tolerable distinctness the layers of growth. The form and structure of the object indicated plainly enough that it had been a scale, a conclusion confirmed by the detection of the phosphate of lime in its composition. At this period I inserted a short notice of the occurrence of these scales in our provincial newspaper, theFife Herald, for the purpose of attracting the attention of the workmen and others in the neighborhood, in order to secure the preservation of any other specimens which might occur.
"Nearly a year after these scales had been discovered, not only in the upper, but even in some of the lower beds of the Yellow Sandstone, I was informed thatoyster shellshad been found in a quarry in the Old Red Sandstone at Clashbennie, near Errol, in Perthshire, and that specimens were in the possession of a gentleman in Perth. Interested in the intelligence, I lost no time in visiting Perth, and was gratified to find that the supposed oyster shells were, in fact, similar to those which I had ascertained to occur in a higher part of the series. The scales were, however, of a larger size, some of them exceeding three inches in length, and one eighth of an inch in thickness. Upon my visit to the quarry, I found the scales, as in the Yellow Sandstone, most abundant in those parts of the rock which exhibited a brecciated aspect. Many patches a foot in length, full of scales, have occurred; but as yet no entire impression of a fish has been obtained.
"Another scale,differing from those already noticed, (seePlate II., fig. 3, 'figure of an oblong tubercle plate traversed diagonally by lines, which, bisecting one another a little above the centre, resembles a St. Andrew's cross, and marked on the edges by faintly radiating lines,') is about an inch and a quarter in length, and an inch in breadth. In external appearance it bears a very close resemblance to some of the scales on the common sturgeon, and may, with some probability, be referred to an extinct species of the genusAccipenser."—(Cheek's Edinburgh Journal, Feb. 1831, p. 85.)
"Dr. Fleming, in 1830," says Dr. Anderson, "read before the Wernerian Society a notice 'on the occurrence of scales of vertebrated animals in the Old Red Sandstone of Fifeshire.' These organisms, as described by him, occurred in the Yellow Sandstone of Drumdryan and the Gray Sandstone of Parkhill. From the former locality scales of a fish were obtained.... The same paper (Professor Fleming's) contains a notice ofsimilar scalesin the Old Red Sandstone of Clashbennie, near Errol, in Perthshire, one of which is described as bearing 'a very close resemblance to some of the scales on the common sturgeon, and may with some probability be referred to an extinct species of the genusAccipenser.'"—(Professor Jameson's Edin. New Phil. Journal, Oct. 1837, p. 138.)
The deposit, too, abounds in teeth, various enough in their forms to indicate a corresponding variety of families and genera among the ichthyolites to which they belonged. Some are nearly straight, like those of theHoloptychiusof the Coal Measures; some are bent, like the beak of a hawk or eagle, into a hook-form; some incline first in one direction, and then in the opposite one,like nails that have been drawn out of a board by the carpenter at two several wrenches, and bent in opposite angles at each wrench; some are bulky and squat, some long and slender; and in almost all the varieties, whether curved or straight, squat or slim, the base is elegantly striated like the flutings of the column. In the splendid specimen found inthe sandstones of the Findhorn, the tooth is still attached to a portion of the jaw, and shows, from the nature of the attachment, that the creature to which it belonged must have been a true fish, not a reptile. The same peculiarity is observable in two other very fine specimens in the collection of Mr. Patrick Duff, of Elgin. Both in saurians and in toothedcetaceæ, such as the porpoise, the teeth are inserted in sockets. In the ichthyolites of this formation, so far as these are illustrated by its better specimens, the teeth, as in existing fish, are merely placed flat upon the jaw, or in shallow pits, which seem almost to indicate that the contrivance of sockets might be afterwards resorted to. Immediately over the sandstoneand conglomerate belt in which these organisms occur, there rests, as has been said, a band of limestone, and over the limestone a thick bed of yellow sandstone, in which the system terminates, and which is overlaid in turn by the lower beds of the carboniferous group.
The limestone band is unfossiliferous, and resembling, in mineralogical character, the Cornstones of England and Wales, it has been described as the Cornstone of Scotland; but the fact merely furnishes one illustration of many, of the inadequacy of a mineralogical nomenclature for the purposes of the geologist. In the neighborhood of Cromarty the lower formation abounds in beds of nodular limestone, identical in appearance with the Cornstone;—in England similar beds occur so abundantly in the middle formation, that it derives its name from them;—in Fife they occur in the upper formation exclusively. Thus the formation of theCoccosteusandDipterusis a cornstone formation in the first locality; that of theCephalaspisand the gigantic lobster in the second; that of theHoloptychius nobilissimusin the third. We have but to vary our field of observation to find all the formations of the systemCornstone formationsin turn. The limestone band of the upper member presents exactly similar appearances in Moray as in Fife. It is in both of a yellowish green or gray color, and a concretionary structure, consisting of softer and harder portions, that yield so unequally to the weather, as to exhibit in exposed cliffs and boulders a brecciated aspect, as if it had been a mechanical, not a chemical deposit; though its origin must unquestionably have been chemical. It contains minute crystals of galena, and abounds in masses of a cherty, siliceous substance that strikes fire with steel, and which, from the manner in which they are incorporated with the rock, show that they must have beenformed along with it. From this circumstance, and from the general resemblance it bears to the deposits of the thermal waters of volcanic districts which precipitate siliceous mixed with calcareous matter, it has been suggested, and by no mean authority, that it must have derived its origin from hot springs. The bed is several yards in thickness; and as it appears both in Moray and in Fife, in localities at least a hundred and twenty miles apart, it must have been formed, if formed at all, in this manner, at a period when the volcanic agencies were in a state of activity at no great distance from the surface.
The upper belt of yellow stone, the terminal layer of the pyramid, is fossiliferous both in Moray and Fife—more richly so in the latter county than even the conglomerate belt that underlies it, and its organisms are better preserved. It was in this upper layer, in Drumdryan quarry, to the south of Cupar, that Professor Fleming found the first-discovered scales of theHoloptychius. At Dura Den, in the same neighborhood, a singularly rich deposit of animal remains was laid open a few years ago, by some workmen, when employed in excavating a water-course for a mill. The organisms lay crowded together, a single slab containing no fewer than thirty specimens, and all in a singularly perfect state of preservation. The whole space excavated did not exceed forty square yards in extent, and yet in these forty yards there were found several genera of fishes new to Geology, and not yet figured nor described—a conclusive proof in itself that we have still very much to learn regarding the fossils of the Old Red Sandstone. By much the greater portion of the remains disinterred on this occasion were preserved by a lady in the neighborhood; and the news of the discovery spreading over the district, the Rev. Dr. Anderson, of Newburgh,was fortunately led to discover them anew in her possession. The most abundant organism of the group was a variety ofPterichthys—the sixth species of this very curious genus now discovered in the Old Red Sandstones of Scotland; and as the Doctor had been lucky enough to find out for himself, some years before, that the scales of theHoloptychiuswere oyster shells, he now ascertained, with quite as little assistance from without, that thePterichthysmust have been surely a huge beetle. As a beetle, therefore, he figured and described it in the pages of a Glasgow topographical publication—Fife Illustrated. True, the characteristic elytra were wanting, and some six or seven tubercle plates substituted in their room; nor could the artist, with all his skill, supply the creature with more than two legs; but ingenuity did much for it, notwithstanding; and by lengthening the snout, insect-like, into a point—by projecting an eye, insect-like, on what had mysteriously grown into a head—by rounding the body, insect-like, until it exactly resembled that of the large "twilight shard"—by exaggerating the tubercles seen in profile on the paddles until they stretched out, insect-like, into bristles—and by carefully sinking the tail, which was not insect-like, and for which no possible use could be discovered at the time—the Doctor succeeded in making thePterichthysof Dura Den a very respectable beetle indeed. In a later publication, an Essay on the Geology of Fifeshire, which appeared in September last in theQuarterly Journal of Agriculture, he states, after referring to his former description, that among the higher geological authorities some were disposed to regard the creature as an extinct crustaceous animal, and some as belonging to a tribe closely allied to theChelonia. Agassiz, as the writer of these chapters ventured some months ago to predict, has since pronounced it a fish—aPterichthysspecificallydifferent from the five varieties of this ichthyolite which occur in the lower formation of the system, but generically the same. I very lately enjoyed the pleasure of examining thebona fideichthyolite itself—one of the specimens of Dura Den, and apparently one of the more entire—in the collection of Professor Fleming. Its character as aPterichthysI found very obvious; but neither the Professor nor myself was ingenious enough to discover in it any trace of the beetle of Dr. Anderson.[AT]
[AT]This interesting ichthyolite has since been regarded by Agassiz as the representative of a distinct genus, to which he gives the namePamphractus. As exhibited in his restoration, however, it seems to differ little, if at all, (if I may venture the suggestion,) from a Pterichthys viewed on the upper side. In Agassiz's beautiful restoration of Pterichthys, and his accompanying prints of the fossils illustrative of that genus, it is, with but one doubtful exception, the under side of the animal that is presented; and hence a striking difference apparent between his representations of the two genera, which would scarce obtain had the upper, not the under side ofPterichthysbeen exhibited. In verification of this remark, let the reader who has access to theMonographic Poissons Fossilescompare the restoration ofPamphractus(Old Red, Tab. VI., fig. 2) with the upper side ofPterichthys, as figured in this volume,Plate I., fig. 1, making, of course, the due allowance for a difference of species.
[AT]This interesting ichthyolite has since been regarded by Agassiz as the representative of a distinct genus, to which he gives the namePamphractus. As exhibited in his restoration, however, it seems to differ little, if at all, (if I may venture the suggestion,) from a Pterichthys viewed on the upper side. In Agassiz's beautiful restoration of Pterichthys, and his accompanying prints of the fossils illustrative of that genus, it is, with but one doubtful exception, the under side of the animal that is presented; and hence a striking difference apparent between his representations of the two genera, which would scarce obtain had the upper, not the under side ofPterichthysbeen exhibited. In verification of this remark, let the reader who has access to theMonographic Poissons Fossilescompare the restoration ofPamphractus(Old Red, Tab. VI., fig. 2) with the upper side ofPterichthys, as figured in this volume,Plate I., fig. 1, making, of course, the due allowance for a difference of species.
Is it not interesting to find this very curious genus in both the lowest and highest fossiliferous beds of the system, and constituting, like theTrilobitegenus of the Silurian group, its most characteristic organism? TheTrilobitehas a wide geological range, extending from the upper Cambrian rocks to the upper Coal Measures. But though the range of the genus is wide, that of every individual species of which it consists is very limited. TheTrilobitesof the upper Coal Measures differ from those of the Mountain Limestone;these again, with but one exception, from theTrilobitesof the upper Silurian strata; these yet again from theTrilobitesof the underlying middle beds; and these from theTrilobitesthat occur in the base of the system. Like the coins and medals of the antiquary, each represents its own limited period; and the whole taken together yield a consecutive record. But while we find them merely scattered over the later formations in which they occur, and that very sparingly, in the Silurian System we find them congregated in such vast crowds, that their remains enter largely into the composition of many of the rocks which compose it. TheTrilobiteis the distinguishing organism of the group, marrying, if I may so express myself, its upper and lower beds; and what theTrilobiteis to the Silurian formations, thePterichthysseems to be to the formations of the Old Red Sandstone; with this difference, that, so far as is yet known, it is restricted to this system alone, occurring in neither the Silurian System below, nor in the Coal Measures above.
I am but imperfectly acquainted with the localities in which the upper beds of the Old Red Sandstone underlie the lower beds of the Coal Measures, or where any gradation of character appears. The upper yellow sandstone belt is extensively developed in Moray, but it contains no trace of carbonaceous matter in even its higher strata, and no other remains than those of theHoloptychiusand its contemporaries. The system in the north of Scotland differs as much from the carboniferous group in its upper as in its lower rocks; and a similar difference has been remarked in Fife, where the groups appear in contact a few miles to the west of St. Andrew's. In England, in repeated instances, the junction, as shown by Mr. Murchison, in singularly instructive sections, is well marked, the carboniferous limestones restingconformably on the Upper Old Red Sandstone. No other system interposed between them.
There is a Rabbinical tradition that the sons of Tubal-Cain, taught by a prophet of the coming deluge, and unwilling that their father's arts should be lost in it to posterity, erected two obelisks of brass, on which they inscribed a record of his discoveries, and that thus the learning of the family survived the cataclysm. The flood subsided, and the obelisks, sculptured from pinnacle to base, were found fast fixed in the rock. Now, the twin pyramids of the Old Red Sandstone, with their party-colored bars, and their thickly crowded inscriptions, belong to a period immensely more remote than that of the columns of the antediluvians, and they bear a more certain record. I have, perhaps, dwelt too long on their various compartments; but the Artist by whom they have been erected, and who has preserved in them so wonderful a chronicle of his earlier works, has willed surely that they should be read, and I have perused but a small portion of the whole. Years must pass ere the entire record can be deciphered; but, of all its curiously inscribed sentences, the result will prove the same—they will all be found to testify of the Infinite Mind.
Speculations in the Old Red Sandstone, and their Character.—George, first Earl of Cromarty.—His Sagacity as a Naturalist at fault in one Instance.—Sets himself to dig for Coal in the Lower Old lied Sandstone.—Discovers a fine Artesian Well.—Value of Geological Knowledge in an economic View.—Scarce a Secondary Formation in the Kingdom in which Coal has not been sought for.—Mineral Springs of the Lower Old Red Sandstone.—Strathpeffer.—Its Peculiarities whence derived.—Chalybeate Springs of Easter Ross and the Black Isle.—Petrifying Springs.—Building-Stone and Lime of the Old Red Sandstone.—Its various Soils.
Therehas been much money lost, and a good deal won, in speculations connected with the Old Red Sandstone. The speculations in which money has been won have consorted, if I may so speak, with the character of the system, and those in which money has been lost have not. Instead, however, of producing a formal chapter on the economic uses to which its various deposits have been applied, or the unfortunate undertakings which an acquaintance with its geology would have prevented, I shall throw together, as they occur to me, a few simple facts illustrative of both.
George, first Earl of Cromarty, seems, like his namesake and contemporary, the too celebrated Sir George M'Kenzie, of Roseavoch, to have been a man of an eminently active and inquiring mind. He found leisure, in the course of a very busy life, to write several historical dissertations of great research, and a very elaborateSynopsis Apocalyptica. He is the author, too, of an exceedingly curious letter on the "Second Sight," addressed to the philosophic Boyle, whichcontains a large amount of amusing and extraordinary fact; and his description of the formation of a peat-moss in the central Highlands of Ross-shire has been quoted by almost every naturalist who, since the days of the sagacious, nobleman, has written on the formation of peat. His life was extended to extreme old age; and as his literary ardor remained undiminished till the last, some of his writings were produced at a period when most other men are sunk in the incurious indifferency and languor of old age. And among these later productions are his remarks on peat. He relates that, when a very young man, he had marked, in passing on a journey through the central Highlands of Ross-shire, a wood of very ancient trees, doddered and moss-grown, and evidently passing into a state of death through the last stages of decay. He had been led by business into the same district many years after, when in middle life, and found that the wood had entirely disappeared, and that the heathy hollow which it had covered was now occupied by a green, stagnant morass, unvaried in its tame and level extent by either bush or tree. In his old age he again visited the locality, and saw the green surface roughened with dingy-colored hollows, and several Highlanders engaged in it in cutting peat in a stratum several feet in depth. What he had once seen an aged forest had now become an extensive peat-moss.
Some time towards the close of the seventeenth century he purchased the lands of Cromarty, where his turn for minute observation seems to have anticipated—little, however, to his own profit—some of the later geological discoveries. There is a deep, wooded ravine in the neighborhood of the town, traversed by a small stream, which has laid bare, for the space of about forty yards in the opening of the hollow, the gray sandstone and stratified clays of the inferior fishbed. The locality is rather poor in ichthyolites, though I have found in it, after minute search, a few scales of theOsteolepis, and on one occasion one of the better marked plates of theCoccosteus; but in the vegetable impressions peculiar to the formation it is very abundant. These are invariably carbonaceous, and are not unfrequently associated with minute patches of bitumen, which, in the harder specimens, present a coal-like appearance; and the vegetable impressions and the bitumen seem to have misled the sagacious nobleman into the belief that coal might be found on his new property. He accordingly brought miners from the south, and set them to bore for coal in the gorge of the ravine. Though there was probably a register kept of the various strata through which they passed, it must have long since been lost; but from my acquaintance with this portion of the formation, as shown in the neighboring sections, where it lies uplifted against the granitic gneiss of the Sutors, I think I could pretty nearly restore it. They would first have had to pass for about thirty feet through the stratified clays and shales of the ichthyolite bed, with here and there a thin band of gray sandstone, and here and there a stratum of lime; they would next have had to penetrate through from eighty to a hundred feet of coarse red and yellow sandstone, the red greatly predominating. They would then have entered the great conglomerate, the lowest member of the formation; and in time, if they continued to urge their fruitless labors, they would arrive at the primary rock, with its belts of granite, and its veins and huge masses of hornblende. In short, there might be some possibility of their penetrating to the central fire, but none whatever of their ever reaching a vein of coal. From a curious circumstance, however, they were prevented from ascertaining, by actual experience, the utter barrenness of the formation.
Directly in the gorge of the ravine, where we may see the partially wooded banks receding as they ascend from the base to the centre, and then bellying over from the centre to the summit, there is a fine chalybeate spring, surmounted by a dome of hewn stone. It was discovered by the miners when in quest of the mineral which they did not and could not discover, and forms one of the finest specimens of a true Artesian well which I have any where seen. They had bored to a considerable depth, when, on withdrawing the kind of auger used for the purpose, a bolt of water, which occupied the whole diameter of the bore, came rushing after, like the jet of a fountain, and the work was prosecuted no further; for, as steam-engines were not yet invented, no pit could have been wrought with so large a stream issuing into it; and as the volume was evidently restricted by the size of the bore, it was impossible to say how much greater a stream the source might have supplied. The spring still continues to flow towards the sea, between its double row of cresses, at the rate of about a hogshead per minute—a rate considerably diminished, it is said, from its earlier volume, by some obstruction in the bore. The waters are not strongly tinctured—a consequence, perhaps, of their great abundance; but we may see every pebble and stock in their course enveloped by a ferruginous coagulum, resembling burnt sienna, that has probably been disengaged from the dark red sandstone below, which is known to owe its color to the oxide of iron. A Greek poet would probably have described the incident as the birth of the Naiad; in the north, however, which, in an earlier age, had also its Naiads, though, like the fish of the Old Red Sandstone, they have long since become extinct, the recollection of it is merely preserved by tradition, as a curious, though by no means poetical fact, and by the name ofthe well, which is still known as the well of thecoal-heugh—the old Scotch name for a coal-pit. Calderwood tells us, in his description of a violent tempest which burst out immediately as his persecutor, James VI., breathed his last, that in Scotland the sea rose high upon the land, and that many "coal-heughs were drowned."
There is no science whose value can be adequately estimated by economists and utilitarians of the lower order. Its true quantities cannot be represented by arithmetical figures or monetary tables; for its effects on mind must be as surely taken into account as its operations on matter, and what it has accomplished for the human intellect as certainly as what it has done for the comforts of society or the interests of commerce. Who can attach a marketable value to the discoveries of Newton? I need hardly refer to the often-quoted remark of Johnson; the beauty of the language in which it is couched has rendered patent to all the truth which it conveys. "Whatever withdraws us from the power of the senses," says the moralist—"whatever makes the past, the distant, or the future, predominate over the present, advances us in the dignity of thinking beings." And Geology, in a peculiar manner, supplies to the intellect an exercise of this ennobling character. But it has, also, its cash value. The time and money squandered in Great Britain alone in searching for coal in districts where the well-informed geologist could have at once pronounced the search hopeless, would much more than cover the expense at which geological research has been prosecuted throughout the world. There are few districts in Britain occupied by the secondary deposits, in which, at one time or another, the attempt has not been made. It has been the occasion of enormous expenditure in the south of England among the newer formations, where the coal, if it at alloccurs, (for we occasionally meet with wide gaps in the scale,) must be buried at an unapproachable depth. It led in Scotland—in the northern county of Sutherland—to an unprofitable working for many years of a sulphureous lignite of the inferior Oolite, far above the true Coal Measures. The attempt I have just been describing was made in a locality as far beneath them. There is the scene of another and more modern attempt in the same district, on the shores of the Moray Frith, in a detached patch of Lias, where a fossilized wood would no doubt be found in considerable abundance, but no continuous vein even of lignite. And it is related by Dr. Anderson, of Newburgh, that a fruitless and expensive search after coal has lately been instituted in the Old Red Sandstone beds which traverse Strathearn and the Carse of Gowrie, in the belief that they belong not to the Old, but to the New Red Sandstone—a formation which has been successfully perforated in prosecuting a similar search in various parts of England. All these instances—and there are hundreds such—show the economic importance of the study of fossils. The Oolite has its veins of apparent coal on the coast of Yorkshire, and its still more amply developed veins—one of them nearly four feet in thickness—on the eastern coast of Sutherlandshire; the Lias has its coniferous fossils in great abundance, some of them converted into a lignite which can scarce be distinguished from a true coal; and the bituminous masses of the Lower Old Red, and its carbonaceous markings, appear identical, to an unpractised eye, with the impressions on the carboniferous sandstones, and the bituminous masses which they, too, are occasionally found to enclose. Nor does the mineralogical character of its middle beds differ in many cases from that of the lower members of the New Red Sandstone. I have seen the older rock in the northof Scotland as strongly saliferous as any of the newer sandstones, of well nigh as bright a brick-red tint, of as friable and mouldering a texture, and variegated as thickly with its specks and streaks of green and buff-color. But in all these instances there are strongly characterized groups of fossils, which, like the landmarks of the navigator, or the findings of his quadrant, establish the true place of the formations to which they belong. Like the patches of leather, of scarlet, and of blue, which mark the line attached to the deep-sea lead, they show the various depths at which we arrive. The Earls of Sutherland set themselves to establish a coal-work among the chambered univalves of the Oolite, and a vast abundance of its peculiar bivalves. The coal-borers who perforated the Lias near Cromarty passed every day to and from their work over one of the richest deposits of animal remains in the kingdom—a deposit full of the most characteristic fossils; and drove their auger through a thousand belemnites and ammonites of the upper and inferior Lias, and through gryphites and ichthyodorulites innumerable. The sandstones of Strathearn and the Carse of Gowrie yield their plates and scales of theHoloptychius, the most abundant fossil of the Upper Old Red; and the shale of the little dell in which the first Earl of Cromarty set his miners to work, contains, as I have said, plates of the Coccosteus and scales of theOsteolepis—fossils found only in the Lower Old Red. Nature, in all these localities, furnished the index, but men lacked the skill necessary to decipher it.[AU]I may mention that, independently of their well-marked organisms, there is a simple test through which the lignites of the newer formations may be distinguished from the true coal of the carboniferous system. Coal, though ground into an impalpable powder, retains its deep black color, and may be used as a black pigment; lignite, on the contrary, when fully levigated, assumes a reddish, or, rather, umbry hue.