THE
OLD RED SANDSTONE;
OR,
NEW WALKS IN AN OLD FIELD.

BY

HUGH MILLER,

AUTHOR OF "FOOT-PRINTS OF THE CREATOR," ETC.

ILLUSTRATED WITH NUMEROUS ENGRAVINGS.

FROM THE FOURTH LONDON EDITION.

BOSTON:
GOULD AND LINCOLN,
59 WASHINGTON STREET.
1851.

STEREOTYPED AT THE BOSTON STEREOTYPE FOUNDRY.

Printed by G. C. Rand & Co. No. 3 Cornhill.

DEDICATION.

TO

RODERICK IMPEY MURCHISON, Esq., F. R. S., Etc.,

PRESIDENT OF THE GEOLOGICAL SOCIETY.

In the autumn of last year, I sat down to write a few geological sketches for a newspaper; the accumulated facts of twenty years crowded upon me as I wrote, and the few sketches have expanded into a volume. Permit me, honored Sir, to dedicate this volume to you. Its imperfections are doubtless many, for it has been produced under many disadvantages; but it is not the men best qualified to decide regarding it whose criticisms I fear most; and I am especially desirous to bring it under your notice, as of all geologists the most thoroughly acquainted with those ancient formations which it professes partially to describe. I am, besides, desirous it should be known, and this, I trust, from other motives than those of vanity, that, when prosecuting my humble researches in obscurity and solitude, the present President of the Geological Society did not deem it beneath him to evince an interest in the results to which they led, and to encourage and assist the inquirer with his advice. Accept, honored Sir, my sincere thanks for your kindness.

Smith, the father of English Geology, loved to remark that he had been born upon the Oolite—the formation whose various deposits he was the first to distinguish and describe, and from which, as from the meridian line of the geographer, the geological scale has been graduated on both sides. I have thought of the circumstance when, on visiting in my native district the birthplace of the author of the Silurian System, I found it situated among the more ancient fossiliferous rocks of the north of Scotland—the Lower Formation of the Old Red Sandstone spreading out beneath and around it, and the first-formed deposit of the system, the Great Conglomerate, rising high on the neighboring hills. It is unquestionably no slight advantage to be placed, at that early stage of life, when the mind collects its facts with greatest avidity, and the curiosity is most active, in localities where there is much to attract observation that has escaped the notice of others. Like the gentleman whom I have now the honor of addressing, I too was born on the Old Red Sandstone, and first broke ground as an inquirer into geological fact in a formation scarce at all known to the geologist, and in which there still remains much for future discoverers to examine and describe. Hence an acquaintance, I am afraid all too slight, with phenomena which, if intrinsically of interest, may be found to have also the interest of novelty to recommend them, and with organisms which, though among the most ancient of things in their relation to the world's history, will be pronounced new by the geological reader in their relation to human knowledge. Hence, too, my present opportunity of subscribing myself, as the writer of a volume on the Old Red Sandstone,

Honored Sir,
With sincere gratitude and respect,
Your obedient humble Servant,
HUGH MILLER.

Edinburgh, May 1, 1841.

[PREFACE.]

Nearly one third of the present volume appeared a few months ago in the form of a series of sketches in the Witness newspaper. A portion of the first chapter was submitted to the public a year or two earlier, in Chambers's Edinburgh Journal. The rest, amounting to about two thirds of the whole, appears for the first time.

Every such work has its defects. The faults of the present volume—faults all too obvious, I am afraid—would have been probably fewer had the writer enjoyed greater leisure. Some of them, however, seem scarce separable from the nature of the subject: there are others for which, from their opposite character, I shall have to apologize in turn to opposite classes of readers. My facts would, in most instances, have lain closer had I written for geologists exclusively, and there would have been less reference to familiar phenomena. And had I written for only general readers, my descriptions of hitherto undescribed organisms, and the deposits of little-known localities, would have occupied fewer pages, and would have been thrown off with, perhaps, less regard to minute detail than to pictorial effect. May I crave, while addressing myself, now to the one class, and now to the other, the alternate forbearance of each?

Such is the state of progression in geological science, that the geologist who stands still for but a very little, must be content to find himself left behind. Nay, so rapid is the progress, that scarce a geological work passes through the press in which some of the statements of the earlier pages have not to be modified, restricted, or extended in the concluding ones. The present volume shares, in this respect, in what seems the common lot. In describing the Coccosteus, the reader will find it stated that the creature, unlike its contemporary the Pterichthys, was unfurnished with arms. Ere arriving at such a conclusion, I had carefully examined at least a hundred different Coccostei; but the positive evidence of one specimen outweighs the negative evidence of a hundred; and I have just learned from a friend in the north, (Mr. Patrick Duff, of Elgin,) that a Coccosteus lately found at Lethen-bar, and now in the possession of Lady Gordon Gumming, of Altyre, is furnished with what seem uncouth, paddle-shaped arms, that project from the head.[A] All that I have given of the creature, however, will be found true to the actual type; and that parts should have been omitted will surprise no one who remembers that many hundred belemnites had been figured and described ere a specimen turned up in which the horny prolongation, with its enclosed ink-bag, was found attached to the calcareous spindle; and that even yet, after many thousand trilobites have been carefully examined, it remains a question with the oryctologist, whether this crustacean of the earliest periods was furnished with legs, or creeped on an abdominal foot, like the snail.

[A] As these paddle-shaped arms have not been introduced by Agassiz into his restoration of the Coccosteus, their existence, at least as arms, must still be regarded as problematical. There can be no doubt, however, that they existed as plates of very peculiar form, and greatly resembling paddles, and that they served in the economy of the animal some still unaccounted for purpose.

I owe to the kindness of Mr. Robertson, Inverugie, the specimen figured in [Plate V.], fig. 7, containing shells of the only species yet discovered in the Old Red Sandstone of Scotland. They occur in the Lower Formation of the system, in a quarry near Kirkwald, in which the specimen figured, with several others of the same kind, was found by Mr. Robertson, in the year 1834. In referring to this shell, page 99,[B] I have spoken of it as a delicate bivalve, much resembling a Venus; drawing my illustration, naturally enough, when describing the shell of an ocean deposit, rather from among marine, than fluviatile testacea. I have since submitted it to Mr. Murchison, who has obligingly written me that he "can find no one to say more regarding it than that it is very like a Cyclas." He adds, however, that it must be an ocean production notwithstanding, seeing that all its contemporaries in England, Scotland, and Russia, whether shells or fish, are unequivocally marine.

[B] Page 90 of the present edition.

With the exception of two of the figures in [Plate IX.], the figures of the Cephalaspis and the Holoptychius, and one of the sections in the Frontispiece, section 2, all the prints of the volume are originals. To Mr. Daniel Alexander, of Edinburgh,—a gentleman, who to the skill and taste of the superior artist, adds no small portion of the knowledge of the practical geologist,—I am indebted for several of the drawings; that of fig. 2 in [Plate V.], fig. 1 in [Plate VI.], fig. 2 in [Plate VIII.], and figs. 3 and 4 in plate IX. I am indebted to another friend for fig. 1, in [Plate VII.] Whatever defects may be discovered in any of the others, must be attributed to the untaught efforts of the writer, all unfamiliar, hitherto, with the pencil, and with by much too little leisure to acquaint himself with it now.

[AMERICAN PUBLISHERS' NOTICE.]

The publishers take pleasure in presenting to the American reader this interesting work of Hugh Miller, in which are restored to our view some of the phenomena which occurred in the earlier formations of the crust of the earth, belonging to those inconceivably remote ages when living things first appeared;—a work so scientific, and yet so illustrated with familiar objects and scenes, as to be well understood by those little versed in Geology. The grand conclusions which the author deduces from apparently trifling circumstances that every one has noticed a hundred times, without being the wiser, illustrate the difference between the philosopher and the common observer; and the simple and pictorial style in which they are delineated renders the work peculiarly fascinating.

This is a reprint of the fourth English edition, without additions or alterations, excepting the omission of the prefatory Notes to the second and third editions. In the first of these, the author states that he had added about fifteen pages to the first edition, chiefly relating to that middle formation of the system to which the organisms of Balruddery and Carmylie belong, the representative of the Cornstones in England. Some matters there given as merely conjectural were also replaced by ascertained facts. In the latter, he announces that the somewhat bold prediction made by him in the first edition, in 1841, that the ichthyolites of the Old Red Sandstone would be found at least equal to those of all the geological formations united, at the death of Cuvier, was already more than fulfilled. Cuvier enumerated ninety-two species of fossil fishes; Agassiz, in 1846, enumerated one hundred and five in the Old Red Sandstone alone, a formation which had been regarded as poorer in organisms than any other. In this edition was given the list of species, as determined and arranged by Professor Agassiz. Many additions in the shape of notes were also made.

In the first two editions it was stated that there was a gradual increase of size observable in the progress of ichthyolic life, and that the Old Red System exhibited, in its successive formations, this gradation of bulk, beginning with an age of dwarfs, and ending with an age of giants. Since then, it has been ascertained that there were giants among the dwarfs. The remains of one of the largest fish found any where, has been discovered in its lowest formation; whereby he was convinced that the theory of a gradual progression in size, from the earlier to the later Palæozoic formations, though based originally on no inconsiderable amount of negative evidence, must be permitted to drop. On this fact he has based his incontrovertible argument against the "development theory" in his more recent work, already given to the American Public, "Foot-Prints of the Creator."

Boston, January, 1851.

[CONTENTS.]

CHAPTER I.

PAGE

The Working-man's true Policy.—His only Mode of acquiring Power.—The Exercise of the Faculties essential to Enjoyment.—No necessary Connection between Labor and Unhappiness.—Narrative.—Scenes in a Quarry.—The two dead Birds.—Landscape.—Ripple Markings on a Sandstone Slab.—Boulder Stones.—Inferences derived from their water-worn Appearance.—Sea-coast Section.—My first discovered Fossil.—Lias Deposit on the Shores of the Moray Frith.—Belemnite.—Result of the Experience of half a Lifetime of Toil.—Advantages of a Wandering Profession in Connection with the Geology of a Country.—Geological Opportunities of the Stone-Mason.—Design of the present Work,

[1-14]

CHAPTER II.

The Old Red Sandstone.—Till very lately its Existence as a distinct Formation disputed.—Still little known.—Its great Importance in the Geological Scale.—Illustration.—The North of Scotland girdled by an immense Belt of Old Red Sandstone.—Line of the Girdle along the Coast.—Marks of vast Denudation.—Its Extent partially indicated by Hills on the western Coast of Ross-shire.—The System of great Depth in the North of Scotland.—Difficulties in the Way of estimating the Thickness of Deposits.—Peculiar Formation of Hill.—Illustrated by Ben Nevis.—Caution to the Geological Critic.—Lower Old Red Sandstone immensely developed in Caithness.—Sketch of the Geology of that County.—Its strange Group of Fossils.—their present Place of Sepulture.—Their ancient Habitat.—Agassiz.—Amazing Progress of Fossil Ichthyology during the last few Years.—Its Nomenclature.—Learned Names repel unlearned Readers.—Not a great deal in them,

[15-34]

CHAPTER III.

Lamarck's Theory of Progression illustrated.—Class of Facts which give Color to it.—The Credulity of Unbelief.—M. Maillet and his Fish-birds.—Gradation not Progress.—Geological Argument.—The Present incomplete without the Past.—Intermediate Links of Creation.—Organisms of the Lower Old Red Sandstone.—The Pterichthys.—Its first Discovery.—Mr. Murchison's Decision regarding it.—Confirmed by that of Agassiz.—Description.—The several Varieties of the Fossil yet discovered.—Evidence of violent Death in the Attitudes in which they are found.—The Coccosteus of the Lower Old Red.—Description.—Gradations from Crustacea to Fishes.—Habits of the Coccosteus.—Scarcely any Conception too extravagant for Nature to realize,

[35-54]

CHAPTER IV.

The Elfin-fish of Gawin Douglas.—The Fish of the Old Red Sandstone scarcely less curious.—Place which they occupied indicated in the present Creation by a mere Gap.—Fish divided into two great Series, the Osseous and Cartilaginous.—Their distinctive Peculiarities.—Geological Illustration of Dr. Johnson's shrewd Objection to the Theory of Soame Jenyns.—Proofs of the intermediate Character of the Ichthyolites of the Old lied Sandstone.—Appearances which first led the Writer to deem it intermediate.—Confirmation by Agassiz.—The Osteolepis.—Order to which, this Ichthyolite belonged.—Description.—Dipterus.—Diplopierus.—Cheirolepis.—Glyptolepis,

[55-78]

CHAPTER V.

The Classifying Principle and its Uses.—Three Groups of Ichthyolites among the Organisms of the Lower Old Red Sandstone.—Peculiarities of the Third Group.—Its Varieties.—Description of the Cheiracanthus.—Of two unnamed Fossils of the same Order.—Microscopic Beauty of these ancient Fish.—Various Styles of Ornament which obtain among them.—The Molluscs of the Formation.—Remarkable chiefly for the Union of modern with ancient Forms which they exhibit.—Its Vegetables.—Importance and Interest of the Record which it furnishes,

[79-94]

CHAPTER VI.

The Lines of the Geographer rarely right Lines.—These last, however, always worth looking at when they occur.—Striking Instance in the Line of the Great Caledonian Valley.—Indicative of the Direction in which the Volcanic Agencies have operated.—Sections of the Old Red Sandstone furnished by the granitic Eminences of the Line.—Illustration.—Lias of the Moray Frith.—Surmisings regarding its original Extent.—These lead to an exploratory Ramble.—Narrative.—Phenomena exhibited in the Course of half an Hour's Walk.—The little Bay.—Its Strata and their Organisms,

[95-108]

CHAPTER VII.

Further Discoveries of the Ichthyolite Beds.—Found in one Locality under a Bed of Peat.—Discovered in another beneath an ancient Burying-ground.—In a third underlying the Lias Formation.—In a fourth overtopped by a still older Sandstone Deposit.—Difficulties in ascertaining the true Place of a newly-discovered Formation.—Caution against drawing too hasty Inferences from the mere Circumstance of Neighborhood.—The Writer receives his first Assistance from without.—Geological Appendix of the Messrs. Anderson, of Inverness.—Further Assistance from the Researches of Agassiz.—Suggestion.—Dr. John Malcolmson.—His extensive Discoveries in Moray.—He submits to Agassiz a Drawing of the Pterichthys.—Place of the Ichthyolites in the Scale at length determined.—Two distinct Platforms of Being in the Formation to which they belong,

[109-124]

CHAPTER VIII.

Upper Formations of the Old Red Sandstone.—Room enough, for each and to spare.—Middle, or Cornstone Formation.—The Cephalaspis its most characteristic Organism.—Description.—The Den of Balruddery richer in the Fossils of this middle Formation than any other Locality yet discovered.—Various Contemporaries of the Cephalaspis.—Vegetable Impressions.—Gigantic Crustacean.—Seraphim.—Ichthyodorulites.—Sketch of the Geology of Forfarshire.—Its older Deposits of the Cornstone Formation.—The Quarries of Carmylie.—Their Vegetable and Animal Remains.—The Upper Formation.—Wide Extent of the Fauna and Flora of the earlier Formations.—Probable Cause,

[125-150]

CHAPTER IX.

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.—The Holoptychius a characteristic Ichthyolite of the Formation.—Description of its huge Scales.—Of its Occipital Bones, Fins, Teeth, and general Appearance.—Contemporaries of the Holoptychius.—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.—the Pterichthys of Dura Den.—Member of a Family peculiarly characteristic of the System.—No intervening Formation between the Old Red Sandstone and the Coal Measures.—The Holoptychius contemporary for a time with the Megalichthys,—The Columns of Tubal-Cain,

[151-172]

CHAPTER X.

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 Red 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 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,

[173-189]

CHAPTER XI.

Geological Physiognomy.—Scenery of the Primary Formations; Gneiss, Mica Schist, Quartz Rock.—Of the Secondary; the Chalk Formations, the Oolite, the New Red Sandstone, the Coal Measures.—Scenery in the Neighborhood of Edinburgh.—Aspect of the Trap Rocks.—The Disturbing and Denuding Agencies.—Distinctive Features of the Old Red Sandstone.—Of the Great Conglomerate.—Of the Ichthyolite Beds.—The Burn of Eathie.—The Upper Old Red Sandstones.—Scene in Moray,

[190-210]

CHAPTER XII.

The two Aspects in which Matter can be viewed; Space and Time.—Geological History of the Earlier Periods.—The Cambrian System.—Its Annelids.—The Silurian System.—Its Corals, Encrinites, Molluscs, and Trilobites.—Its Fish.—These of a high Order, and called into Existence apparently by Myriads.—Opening Scene in the History of the Old Red Sandstone a Scene of Tempest.—Represented by the Great Conglomerate.—Red a prevailing Color among the Ancient Rocks contained in this Deposit.—Amazing Abundance of Animal Life.—Exemplified by a Scene in the Herring Fishery.—Platform of Death.—Probable Cause of the Catastrophe which rendered it such,

[211-225]

CHAPTER XIII.

Successors of the exterminated Tribes.—The Gap slowly filled.—Proof that the Vegetation of a Formation may long survive its Animal Tribes.—Probable Cause.—Immensely extended Period during which Fishes were the Master-existences of our Planet.—Extreme Folly of an Infidel Objection illustrated by the Fact.—Singular Analogy between the History of Fishes as Individuals and as a Class.—Chemistry of the Lower Formation.—Principles on which the Fish-enclosing Nodules were probably formed.—Chemical Effect of Animal Matter in discharging the Color from Red Sandstone.—Origin of the prevailing tint to which the System owes its Name.—Successive Modes in which a Metal may exist.—The Restorations of the Geologist void of Color.—Very different Appearance of the Ichthyolites of Cromarty and Moray,

[226-242]

CHAPTER XIV.

The Cornstone Formation and its Organisms.—Dwarf Vegetation.—Cephalaspides.—Huge Lobster.—Habitats of the existing Crustacea.—No unapt representation of the Deposit of Balruddery, furnished by a land-locked Bay in the neighborhood of Cromarty.—Vast Space occupied by the Geological Formations.—Contrasted with the half-formed Deposits which represent the existing Creation.—Inference.—The formation of the Holoptychius.—Probable origin of its Siliceous Limestone.—Marked increase in the Bulk of the Existences of the System.—Conjectural Cause.—The Coal Measures.—The Limestone of Burdie House Conclusion,

[243-259]

Ichthyolites of the Old Red Sandstone—from Agassiz's "Poissons Fossiles,"

[261-288]

EXPLANATIONS OF THE SECTIONS AND PLATES.

SECTION I.

Represents the Old Red System of Scotland from its upper beds of Yellow Quartzose Sandstone to its Great Conglomerate base. a. Quartzose Yellow Sandstone, b. Impure concretionary limestone enclosing masses of chert, c. Red and variegated sandstones and conglomerate. These three deposits constitute an upper formation of the system, characterized by its peculiar group of fossils. (See Chapter IX.) d. Deposit of gray fissile sandstone which constitutes the middle formation of the system, characterized also by its peculiar organic group. (See Chapter VIII.) e. Red and variegated sandstones, undistinguishable often in their mineral character from the upper sandstones, c, but in general less gritty, and containing fewer pebbles, f. Bituminous schists, g. Coarse gritty sandstone. h. Great Conglomerate. These four beds compose a lower formation of the system, more strikingly marked by its peculiar organisms than even the other two. (See Chapters II. III. IV. and V.) In the section this lower formation is represented as we find it developed in Caithness and Orkney. In fig. 5 it is represented as developed in Cromarty, where, though the fossils are identical with those of the more northern localities, at least one of the deposits, f, is mineralogically different—alternating beds of sandstone and clay, these last enclosing limestone nodules, taking the place of the bituminous schists.

SECTION II.

The Old Red System of England and Wales, as given in the general Section of Mr. Murchison, with the Silurian Rocks beneath and the carboniferous limestone above. i. The point in the geological scale at which vertebrated existences first appear. The three Old Red Sandstone formations of this section correspond in their characteristic fossils with those of Scotland, but the proportions in which they are developed are widely different. The tilestones seem a comparatively narrow stripe in the system in England; the answering formation in Scotland, e, f, g, h, is of such enormous thickness, that it has been held by very superior geologists to contain three distinct formations—e, the New Red Sandstone, f, a representative of the Coal Measures, and g, h, the Old Red Sandstone.

SECTION III.

Interesting case of extensive denudation from existing causes on the northern shore of the Moray Frith. (See pages 197 and 198.) The figures and letters which mark the various beds correspond with those of fig. 5, and of the following section. The "fish-bed," No. 1, represents what the reader will find described in [pp. 221-225] as the "platform of sudden death."

SECTION IV.

Illustration of a fault in the Burn of Eathie, Cromartyshire. (See pages [204] and [205].)

EXPLANATIONS OF THE PLATES.

[Plate I.]—Fig. 1, Restoration of upper side of the elongated species of Pterichthys (P. oblongus,) referred to in page 47. Fig. 2, Pterichthys Milleri. Fig. 3, Part of tail of elongated species, showing portions of the original covering of rhomboidal scales. Fig. 4, Tubercles of Pterichthys magnified.

[Plate II.]—Fig. 2, Restoration of under side of Pterichthys oblongus. Fig. 1, A second specimen of Pterichthys Milleri. Fig. 3, Portion of wing, natural size.

[Plate III.]—Fig. 1, Coccosteus cuspidatus. Fig. 2, Impression of inner surface of large dorsal plate. Fig. 3, Abdominal lozenge-shaped plate. Fig. 4, Portion of jaw, with teeth.

[Plate IV.]—Fig. 1, Restoration of Osteolepis major. Fig. 2, Scales from the upper part of the body magnified. Fig. 3, Large defensive scale which runs laterally along all the single fins. Fig. 4, Under side of scale, showing the attaching bar. Fig. 5, Enamelled and punctulated jaw of the creature. Fig. 6, Magnified portion of fin, showing the enamelled and punctulated rays.

[Plate V.]—Fig. 1, Dipterus macrolepidotus. This figure serves merely to show the place of the fins and the general outline of the ichthyolite. All the specimens the writer has hitherto examined fail to show the minuter details. Fig. 2, Glyptolepis leptopterus. Fig. 3, Single scale of the creature, showing its rustic style of ornament. Fig. 4, Scale with a nail-like attachment. Fig. 5, Under side of scale. Fig. 6, Magnified portion of fin. Fig. 7, Shells of the Old Red Sandstone.

[Plate VI.]—Fig. 1, Cheirolepis Cummingiæ. Fig. 2, Magnified scales. Fig. 3, Magnified portion of fin.

[Plate VII.]—Fig. 1, Cheiracanthus microlepidotus. Fig. 2, Magnified scales. Figs. 3, 4, 5, 6, 7, 8, Vegetable impressions of the Old Red Sandstone.

[Plate VIII.]—Fig. 1, Diplacanthus longispinus. Fig. 2, Diplacanthus striatus. Fig. 3, Magnified scales of fig. 1. Fig. 4, Spine of fig. 2, slightly magnified.

[Plate IX.]—Fig. 1, One of the tail flaps of the gigantic Crustacean of Forfarshire. Fig. 2, Reticulated markings of Carmylie.

[Plate X.]—Fig. 1, Cephalaspis Lyellii, copied from Lyell's Elements of Geology, Fig. 2, Holoptychius nobilissimus, copied on a greatly reduced scale from Murchison's Silurian System, Fig. 3, Scale of Holoptychius, natural size. Fig, 4, Tooth of ditto, also natural size. These last drawn from specimens in the collection of Mr. Patrick Duff, of Elgin.

DIRECTIONS TO THE BINDER.

[NEW WALKS IN AN OLD FIELD;]

OR,

THE OLD RED SANDSTONE.

[CHAPTER I.]

The Working-man's True Policy.—His only Mode of acquiring Power.—The Exercise of the Faculties essential to Enjoyment.—No necessary Connection between Labor and Unhappiness.—Narrative.—Scenes in a Quarry.—The two dead Birds.—Landscape.—Ripple Markings on a Sandstone Slab.—Boulder Stones.—Inference derived from their water-worn Appearance.—Sea-coast Section.—My first discovered Fossil,—Lias Deposit on the Shores of the Moray Frith.—Belemnite.—Result of the Experience of half a Lifetime of Toil.—Advantages of a Wandering Profession in Connection with the Geology of a Country.—Geological Opportunities of the Stone-Mason.—Design of the present Work.

My advice to young working-men, desirous of bettering their circumstances, and adding to the amount of their enjoyment, is a very simple one. Do not seek happiness in what is misnamed pleasure; seek it rather in what is termed study. Keep your consciences clear, your curiosity fresh, and embrace every opportunity of cultivating your minds. You will gain nothing by attending Chartist meetings. The fellows who speak nonsense with fluency at these assemblies, and deem their nonsense eloquence, are totally unable to help either you or themselves; or, if they do succeed in helping themselves, it will be all at your expense. Leave them to harangue unheeded, and set yourselves to occupy your leisure hours in making yourselves wiser men. Learn to make a right use of your eyes: the commonest things are worth looking at—even stones and weeds, and the most familiar animals. Head good books, not forgetting the best of all: there is more true philosophy in the Bible than in every work of every sceptic that ever wrote; and we would be all miserable creatures without it, and none more miserable than you. You are jealous of the upper classes; and perhaps it is too true that, with some good, you have received much evil at their hands. It must be confessed they have hitherto been doing comparatively little for you, and a great deal for themselves. But upper and lower classes there must be, so long as the world lasts; and there is only one way in which your jealousy of them can be well directed. Do not let them get ahead of you in intelligence. It would be alike unwise and unjust to attempt casting them down to your own level, and no class would suffer more in the attempt than yourselves; for you would only be clearing the way, at an immense expense of blood, and under a tremendous pressure of misery, for another and perhaps worse aristocracy, with some second Cromwell or Napoleon at their head. Society, however, is in a state of continual flux: some in the upper classes are from time to time going down, and some of you from time to time mounting up to take their places—always the more steady and intelligent among you, remember; and if all your minds were cultivated, not merely intellectually, but morally also, you would find yourselves, as a body, in the possession of a power which every charter in the world could not confer upon you, and which all the tyranny or injustice of the world could not withstand.

I intended, however, to speak rather of the pleasure to be derived, by even the humblest, in the pursuit of knowledge, than of the power with which knowledge in the masses is invariably accompanied. For it is surely of greater importance that men should receive accessions to their own happiness, than to the influence which they exert over other men. There is none of the intellectual, and none of the moral faculties, the exercise of which does not lead to enjoyment; nay, it is chiefly in the active employment of these that all enjoyment consists; and hence it is that happiness bears so little reference to station. It is a truth which has been often told, but very little heeded or little calculated upon, that though one nobleman may be happier than another, and one laborer happier than another, yet it cannot be at all premised of their respective orders, that the one is in any degree happier than the other. Simple as the fact may seem, if universally recognized, it would save a great deal of useless discontent, and a great deal of envy. Will my humbler readers permit me at once to illustrate this subject, and to introduce the chapters which follow, by a piece of simple narrative? I wish to show them how possible it is to enjoy much happiness in very mean employments. Cowper tells us that labor, though the primal curse, "has been softened into mercy;" and I think that, even had he not done so, I would have found out the fact for myself.

It was twenty years, last February, since I set out a little before sunrise to make my first acquaintance with a life of labor and restraint, and I have rarely had a heavier heart than on that morning. I was but a slim, loose-jointed boy at the time—fond of the pretty intangibilities of romance, and of dreaming when broad awake; and, woeful change! I was now going to work at what Burns has instanced in his "Twa Dogs" as one of the most disagreeable of all employments—to work in a quarry. Bating the passing uneasiness occasioned by a few gloomy anticipations, the portion of my life which had already gone by had been happy beyond the common lot. I had been a wanderer among rocks and woods—a reader of curious books when I could get them—a gleaner of old traditionary stories; and now I was going to exchange all my day-dreams, and all my amusements, for the kind of life in which men toil every day that they may be enabled to eat, and eat every day that they may be enabled to toil!

The quarry in which I wrought lay on the southern shore of a noble inland bay, or frith, rather, with a little clear stream on the one side, and a thick fir wood on the other. It had been opened in the Old Red Sandstone of the district, and was overtopped by a huge bank of diluvial clay, which rose over it in some places to the height of nearly thirty feet, and which at this time was rent and shivered, wherever it presented an open front to the weather, by a recent frost. A heap of loose fragments, which had fallen from above, blocked up the face of the quarry, and my first employment was to clear them away. The friction of the shovel soon blistered my hands; but the pain was by no means very severe, and I wrought hard and willingly, that I might see how the huge strata below, which presented so firm and unbroken a frontage, were to be torn up and removed. Picks, and wedges, and levers were applied by my brother-workmen; and simple and rude as I had been accustomed to regard these implements, I found I had much to learn in the way of using them. They all proved inefficient, however; and the workmen had to bore into one of the inferior strata, and employ gunpowder. The process was new to me, and I deemed it a highly amusing one: it had the merit, too, of being attended with some such degree of danger as a boating or rock excursion, and had thus an interest independent of its novelty. We had a few capital shots: the fragments flew in every direction; and an immense mass of the diluvium came toppling down, bearing with it two dead birds, that in a recent storm had crept into one of the deeper fissures, to die in the shelter. I felt a new interest in examining them. The one was a pretty cock goldfinch, with its hood of vermilion, and its wings inlaid with the gold to which it owes its name, as unsoiled and smooth as if it had been preserved for a museum. The other, a somewhat rarer bird, of the woodpecker tribe, was variegated with light blue and a grayish yellow. I was engaged in admiring the poor little things, more disposed to be sentimental, perhaps, than if I had been ten years older, and thinking of the contrast between the warmth and jollity of their green summer haunts, and the cold and darkness of their last retreat, when I heard our employer bidding the workmen lay by their tools. I looked up, and saw the sun sinking behind the thick fir wood beside us, and the long, dark shadows of the trees stretching downwards towards the shore.

This was no very formidable beginning of the course of life I had so much dreaded. To be sure, my hands were a little sore, and I felt nearly as much fatigued as if I had been climbing among the rocks; but I had wrought and been useful, and had yet enjoyed the day fully as much as usual. It was no small matter, too, that the evening, converted, by a rare transmutation, into the delicious "blink of rest" which Burns so truthfully describes, was all my own. I was as light of heart next morning as any of my brother-workmen. There had been a smart frost during the night, and the rime lay white on the grass as we passed onwards through the fields; but the sun rose in a clear atmosphere, and the day mellowed, as it advanced, into one of those delightful days of early spring, which give so pleasing an earnest of whatever is mild and genial in the better half of the year. All the workmen rested at midday, and I went to enjoy my half-hour alone on a mossy knoll in the neighboring wood, which commands through the trees a wide prospect of the bay and the opposite shore. There was not a wrinkle on the water, nor a cloud in the sky, and the branches were as moveless in the calm as if they had been traced on canvas. From a wooded promontory that stretched half way across the frith, there ascended a thin column of smoke. It rose straight as the line of a plummet for more than a thousand yards, and then, on reaching a thinner stratum of air, spread out equally on every side, like the foliage of a stately tree. Ben Nevis rose to the west, white with the yet unwasted snows of winter, and as sharply defined in the clear atmosphere, as if all its sunny slopes and blue retiring hollows had been chiselled in marble. A line of snow ran along the opposite hills; all above was white, and all below was purple. They reminded me of the pretty French story, in which an old artist is described as tasking the ingenuity of his future son-in-law, by giving him, as a subject for his pencil, a flower-piece composed of only white flowers, of which the one half were to bear their proper color, the other half a deep purple hue, and yet all be perfectly natural; and how the young man resolved the riddle, and gained his mistress, by introducing a transparent purple vase into the picture, and making the light pass through it on the flowers that were drooping over the edge. I returned to the quarry, convinced that a very exquisite pleasure may be a very cheap one, and that the busiest employments may afford leisure enough to enjoy it.

The gunpowder had loosened a large mass in one of the inferior strata, and our first employment, on resuming our labors, was to raise it from its bed. I assisted the other workmen in placing it on edge, and was much struck by the appearance of the platform on which it had rested. The entire surface was ridged and furrowed like a bank of sand that had been left by the tide an hour before. I could trace every bend and curvature, every cross hollow and counter ridge of the corresponding phenomena; for the resemblance was no half resemblance—it was the thing itself; and I had observed it a hundred and a hundred times, when sailing my little schooner in the shallows left by the ebb. But what had become of the waves that had thus fretted the solid rock, or of what element had they been composed? I felt as completely at fault as Robinson Crusoe did on his discovering the print of the man's foot on the sand. The evening furnished me with still further cause of wonder. We raised another block in a different part of the quarry, and found that the area of a circular depression in the stratum below was broken and flawed in every direction, as if it had been the bottom of a pool recently dried up, which had shrunk and split in the hardening. Several large stones came rolling clown from the diluvium in the course of the afternoon. They were of different qualities from the Sandstone below, and from one another; and, what was more wonderful still, they were all rounded and water-worn, as if they had been tossed about in the sea, or the bed of a river, for hundreds of years. There could not, surely, be a more conclusive proof that the bank which had enclosed them so long could not have been created on the rock on which it rested. No workman ever manufactures a half-worn article, and the stones were all half-worn! And if not the bank, why then the sandstone underneath? I was lost in conjecture, and found I had food enough for thought that evening, without once thinking of the unhappiness of a life of labor.

The immense masses of diluvium which we had to clear away rendered the working of the quarry laborious and expensive, and all the party quitted it in a few days, to make trial of another that seemed to promise better. The one we left is situated, as I have said, on the southern shore of an inland bay—the Bay of Cromarty; the one to which we removed has been opened in a lofty wall of cliffs that overhangs the northern shore of the Moray Frith. I soon found I was to be no loser by the change. Not the united labors of a thousand men for more than a thousand years could have furnished a better section of the geology of the district than this range of cliffs. It may be regarded as a sort of chance dissection on the earth's crust. We see in one place the primary rock, with its veins of granite and quartz, its dizzy precipices of gneiss, and its huge masses of hornblende; we find the secondary rock in another, with its beds of sandstone and shale, its spars, its clays, and its nodular limestones. We discover the still little known but highly interesting fossils of the Old Red Sandstone in one deposition; we find the beautifully preserved shells and lignites of the Lias in another. There are the remains of two several creations at once before us. The shore, too, is heaped with rolled fragments of almost every variety of rock,—basalts, ironstones, hypersthenes, porphyries, bituminous shales, and micaceous schists. In short, the young geologist, had he all Europe before him, could hardly choose for himself a better field. I had, however, no one to tell me so at the time, for geology had not yet travelled so far north; and so, without guide or vocabulary, I had to grope my way as I best might, and find out all its wonders for myself. But so slow T was the process, and so much was I a seeker in the dark, that the facts contained in these few sentences were the patient gatherings of years.

In the course of the first day's employment, I picked up a nodular mass of blue limestone, and laid it open by a stroke of the hammer. Wonderful to relate, it contained inside a beautifully finished piece of sculpture—one of the volutes apparently of an Ionic capital; and not the far-famed walnut of the fairy tale, had I broken the shell and found the little dog lying within, could have surprised me more. Was there another such curiosity in the whole world? I broke open a few other nodules of similar appearance,—for they lay pretty thickly on the shore,—and found that there might. In one of these there were what seemed to be the scales of fishes, and the impressions of a few minute bivalves, prettily striated; in the centre of another there was actually a piece of decayed wood. Of all Nature's riddles these seemed to me to be at once the most interesting, and the most difficult to expound. I treasured them carefully up, and was told by one of the workmen to whom I showed them, that there was a part of the shore about two miles farther to the west, where curiously shaped stones, somewhat like the heads of boarding-pikes, were occasionally picked up; and that in his father's days the country people called them thunderbolts, and deemed them of sovereign efficacy in curing bewitched cattle. Our employer, on quitting the quarry for the building on which we were to be engaged, gave all the workmen a half-holiday. I employed it in visiting the place where the thunderbolts had fallen so thickly, and found it a richer scene of wonder than I could have fancied in even my dreams.

What first attracted my notice was a detached group of low lying skerries, wholly different in form and color from the sandstone cliffs above, or the primary rocks a little farther to the west. I found them composed of thin strata of limestone, alternating with thicker beds of a black slaty substance, which, as I ascertained in the course of the evening, burns with a powerful flame, and emits a strong bituminous odor. The layers into which the beds readily separate are hardly an eighth part of an inch in thickness, and yet on every layer there are the impressions of thousands and tens of thousands of the various fossils peculiar to the Lias. We may turn over these wonderful leaves one after one, like the leaves of a herbarium, and find the pictorial records of a former creation in every page. Scallops, and gryphites, and ammonites, of almost every variety peculiar to the formation, and at least some eight or ten varieties of belemnite; twigs of wood, leaves of plants, cones of an extinct species of pine, bits of charcoal, and the scales of fishes; and, as if to render their pictorial appearance more striking, though the leaves of this interesting volume are of a deep black, most of the impressions are of a chalky whiteness. I was lost in admiration and astonishment, and found my very imagination paralyzed by an assemblage of wonders, that seemed to outrival, in the fantastic and the extravagant, even its wildest conceptions. I passed on from ledge to ledge, like the traveller of the tale through the city of statues, and at length found one of the supposed aerolites I had come in quest of, firmly imbedded in a mass of shale. But I had skill enough to determine that it was other than what it had been deemed. A very near relative, who had been a sailor in his time on almost every ocean, and had visited almost every quarter of the globe, had brought home one of these meteoric stones with him from the coast of Java. It was of a cylindrical shape and vitreous texture, and it seemed to have parted in the middle when in a half-molten state, and to have united again, somewhat awry, ere it had cooled enough to have lost the adhesive quality. But there was nothing organic in its structure, whereas the stone I had now found was organized very curiously indeed. It was of a conical form and filamentary texture, the filaments radiating in straight lines from the centre to the circumference. Finely-marked veins like white threads ran transversely through these in its upper half to the point, while the space below was occupied by an internal cone, formed of plates that lay parallel to the base, and which, like watch-glasses, were concave on the under side, and convex on the upper. I learned in time to call this stone a belemnite, and became acquainted with enough of its history to know that it once formed part of a variety of cuttle-fish, long since extinct.

My first year of labor came to a close, and I found that the amount of my happiness had not been less than in the last of my boyhood. My knowledge, too, had increased in more than the ratio of former seasons; and as I had acquired the skill of at least the common mechanic, I had fitted myself for independence. The additional experience of twenty years has not shown me that there is any necessary connection between a life of toil and a life of wretchedness; and when I have found good men anticipating a better and a happier time than either the present or the past, the conviction that in every period of the world's history the great bulk of mankind must pass their days in labor, has not in the least inclined me to scepticism.

My curiosity, once fully awakened, remained awake, and my opportunities of gratifying it have been tolerably ample. I have been an explorer of caves and ravines—a loiterer along sea-shores—a climber among rocks—a laborer in quarries. My profession was a wandering one. I remember passing direct, on one occasion, from the wild western coast of Ross-shire, where the Old Red Sandstone leans at a high angle against the prevailing Quartz Rock of the district, to where, on the southern skirts of Mid-Lothian, the Mountain Limestone rises amid the coal. I have resided one season on a raised beach of the Moray Frith. I have spent the season immediately following amid the ancient granites and contorted schists of the central Highlands. In the north I have laid open by thousands the shells and lignites of the Oolite; in the south I have disinterred from their matrices of stone or of shale the huge reeds and tree ferns of the Carboniferous period. I have been taught by experience, too, how necessary an acquaintance with geology of both extremes of the kingdom is to the right understanding of the formations of either. In the north, there occurs a vast gap in the scale. The Lias leans unconformably against the Old Red Sandstone; there is no Mountain Limestone, no Coal Measures, none of the New Red Marls or Sandstones, Under or Upper. There are at least three entire systems omitted. But the upper portion of the scale is well nigh complete. In one locality we may pass from the Lower to the Upper Lias, in another from the Inferior to the Great Oolite, and onward to the Oxford Clay and the Coral Rag. We may explore, in a third locality, beds identical in their organisms with the Wealden of Sussex. In a fourth we find the flints and fossils of the Chalk. The lower part of the scale is also well nigh complete. The Old Red Sandstone is amply developed in Moray, Caithness, and Ross; and the Grauwacke, in its more ancient unfossiliferous type, rather extensively in Banffshire. But to acquaint one's self with the three missing formations,—to complete one's knowledge of the entire scale by filling up the hiatus,—it is necessary to remove to the south. The geology of the Lothians is the geology of at least two thirds of the gap, and perhaps a little more;—the geology of Arran wants, it is supposed, only the Upper New lied Sandstone to fill it entirely.

One important truth I would fain press on the attention of my lowlier readers. There are few professions, however humble, that do not present their peculiar advantages of observation; there are none, I repeat, in which the exercise of the faculties does not lead to enjoyment. I advise the stone-mason, for instance, to acquaint himself with Geology. Much of his time must be spent amid the rocks and quarries of widely separated localities. The bridge or harbor is no sooner completed in one district, than he has to remove to where the gentleman's seat, or farm-steading is to be erected in another; and so, in the course of a few years, he may pass over the whole geological scale, even when restricted to Scotland, from the Grauwacke of the Lammermuirs, to the Wealden of Moray, or the Chalk-flints of Banffshire and Aberdeen; and this, too, with opportunities of observation, at every stage, which can be shared with him by only the gentleman of fortune, who devotes his whole time to the study. Nay, in some respects, his advantages are superior to those of the amateur himself. The latter must often pronounce a formation unfossiliferous when, after the examination of at most a few days, he discovers in it nothing organic; and it will be found that half the mistakes of geologists have arisen from conclusions thus hastily formed. But the working-man, whose employments have to be carried on in the same formation for months, perhaps years, together, enjoys better opportunities for arriving at just decisions. There are, besides, a thousand varieties of accident which lead to discovery—floods, storms, landslips, tides of unusual height, ebbs of extraordinary fall: and the man who plies his labor at all seasons in the open air has by much the best, chance of profiting by these. There are formations which yield their organisms slowly to the discoverer, and the proofs which establish their place in the geological scale more tardily still. I was acquainted with the Old Red Sandstone of Ross and Cromarty for nearly ten years ere I had ascertained that it is richly fossiliferous—a discovery which, in exploring this formation in those localities, some of our first geologists had failed to anticipate. I was acquainted with it for nearly ten years more ere I could assign to its fossils their exact place in the scale.

In the following chapters I shall confine my observations chiefly to this system and its organisms. To none of the others, perhaps, excepting the Lias of the north of Scotland, have I devoted an equal degree of attention; nor is there a formation among them which, up to the present time, has remained so much a terra incognita to the geologist. The space on both sides has been carefully explored to its upper and lower boundary; the space between has been suffered to remain well nigh a chasm. Should my facts regarding it—facts constituting the slow gatherings of years—serve as stepping-stones laid across, until such time as geologists of greater skill, and more extended research, shall have bridged over the gap, I shall have completed half my design. Should the working-man be encouraged by my modicum of success to improve his opportunities of observation, I shall have accomplished the whole of it. It cannot be too extensively known, that nature is vast and knowledge limited; and that no individual, however humble in place or acquirement, need despair of adding to the general fund.

[CHAPTER II.]

The Old Red Sandstone.—Till very lately its Existence as a distinct Formation disputed.—Still little known.—Its great Importance in the Geological Scale.—Illustration.—The North of Scotland girdled by an immense Belt of Old Red Sandstone.—Line of the Girdle along the Coast.—Marks of vast Denudation.—Its Extent partially indicated by Hills on the Western Coast of Ross-shire.—The System of Great Depth in the North of Scotland.—Difficulties in the way of estimating the Thickness of Deposits.—Peculiar Formation of Hill.—Illustrated by Ben Nevis.—Caution to the Geological Critic.—Lower Old Red Sandstone immensely developed in Caithness.—Sketch of the Geology of that County.—Its strange Group of Fossils.—Their present place of Sepulture.—Their ancient Habitat.—Agassiz.—Amazing Progress of Fossil Ichthyology during the last few Years.—Its Nomenclature.—Learned Names repel unlearned Readers.—Not a great deal in them.

"The Old Red Sandstone," says a Scottish geologist, in a digest of some recent geological discoveries, which appeared a short time ago in an Edinburgh newspaper, "has been hitherto considered as remarkably barren of fossils." The remark is expressive of a pretty general opinion among geologists of even the present time, and I quote it on this account. Only a few years have gone by since men of no low standing in the science disputed the very existence of this formation—system rather, for it contains at least three distinct formations; and but for the influence of one accomplished geologist, the celebrated author of the Silurian System, it would have been probably degraded from its place in the scale altogether. "You must inevitably give up the Old Red Sandstone," said an ingenious foreigner to Mr. Murchison, when on a visit to England about four years ago, and whose celebrity among his own countrymen rested chiefly on his researches in the more ancient formations,—"you must inevitably give up the Old Red Sandstone: it is a mere local deposit, a doubtful accumulation huddled up in a corner, and has no type or representative abroad." "I would willingly give it up if nature would," was the reply; "but it assuredly exists, and I cannot." In a recently published tabular exhibition of the geological scale by a continental geologist, I could not distinguish this system at all. There are some of our British geologists, too, who still regard it as a sort of debatable tract, entitled to no independent status. They find, in what they deem its upper beds, the fossils of the Coal Measures, and the lower graduating apparently into the Silurian System; and regard the whole as a sort of common, which should be divided as proprietors used to divide commons in Scotland half a century ago, by giving a portion to each of the bordering territories. Even the better informed geologists, who assign to it its proper place as an independent formation, furnished with its own organisms, contrive to say all they know regarding it in a very few paragraphs. Lyell, in the first edition of his admirable elementary work, published only two years ago, devotes more than thirty pages to his description of the Coal Measures, and but two and a half to his notice of the Old Red Sandstone.[C]

[C] As the succinct notice of this distinguished geologist may serve as a sort of pocket map to the reader in indicating the position of the system, its three great deposits, and its extent, I take the liberty of transferring it entire.

"OLD RED SANDSTONE.

"It was stated that the Carboniferous formation was surmounted by one called the 'New lied Sandstone,' and underlaid by another called the Old Red, which last was formerly merged in the Carboniferous System, but is now found to be distinguishable by its fossils. The Old Red Sandstone is of enormous thickness in Herefordshire, Worcestershire, Shropshire, and South Wales, where it is seen to crop out beneath the Coal Measures, and to repose on the Silurian Rocks. In that region, its thickness has been estimated by Mr. Murchison at no less than ten thousand feet. It consists there of—

"1st. A quartzose conglomerate, passing downwards into chocolate-red and green sandstone and marl.

"2d. Cornstone and marl, (red and green argillaceous spotted marls, with irregular courses of impure concretionary limestone, provincially called Cornstone, mottled red and green; remains of fishes.)

"3d. Tilestone, (finely laminated hard reddish or green micaceous or quartzose sandstones, which split into tiles; remains of mollusca and fishes.)

"I have already observed that fossils are rare in marls and sandstones in which the red oxide of iron prevails. In the Cornstone, however, of the counties above mentioned, fishes of the genera Cephalaspis and Onchus have been discovered. In the Tilestone, also, Ichthyodorulites of the genus Onchus have been obtained, and a species of Dipterus, with mollusca of the genera Avicula, Area, Cucullæa, Terebratula, Lingula, Turbo, Trochus, Turritella, Bellerophon, Orthoceras, and others.

"By consulting geological maps, the reader will perceive that, from Wales to the north of Scotland, the Old Red Sandstone appears in patches, and often in large tracts. Many fishes have been found in it at Caithness, and various organic remains in the northern part of Fifeshire, where it crops out from beneath the Coal formation, and spreads into the adjoining northern half of Forfarshire; forming, together with trap, the Sidlaw Hills and valley of Strathmore. A large belt of this formation skirts the northern borders of the Grampians, from the sea-coast at Stonehaven and the Frith of Tay to the opposite western coast of the Frith of Clyde. In Forfarshire, where, as in Herefordshire, it is many thousand feet thick, it may be divided into three principal masses—1st. Red and mottled marls, cornstone, and sandstone; 2d. Conglomerate, often of vast thickness; 3d. Tilestones, and paving-stone, highly micaceous, and containing a slight admixture of carbonate of lime. In the uppermost of these divisions, but chiefly in the lowest, the remains of fish have been found, of the genus named by M. Agassiz Cephalaspis, or buckler-headed, from the extraordinary shield which covers the head, and which, has often been mistaken for that of a trilobite of the division Asaphus. A gigantic species of fish, of the genus Holoptychius, has also been found by Dr. Fleming in the Old Red Sandstone of Fifeshire."—Lyell's Elements, pp. 452-4.

It will be found, however, that this hitherto neglected system yields in importance to none of the others, whether we take into account its amazing depth, the great extent to which it is developed both at home and abroad, the interesting links which it furnishes in the zoölogical scale, or the vast period of time which it represents. There are localities in which the depth of the Old Red Sandstone fully equals the elevation of Mount Ætna over the level of the sea, and in which it contains three distinct groups of organic remains, the one rising in beautiful progression over the other. Let the reader imagine a digest of English history, complete from the times of the invasion of Julius Cæsar to the reign of that Harold who was slain at Hastings, and from the times of Edward III. down to the present day, but bearing no record of the Williams, the Henrys, the Edwards, the John, Stephen, and Richard, that reigned during the omitted period, or of the striking and important events by which their several reigns were distinguished. A chronicle thus mutilated and incomplete would be no unapt representation of a geological history of the earth in which the period of the Upper Silurian would be connected with that of the Mountain Limestone, or of the limestone of Burdie House, and the period of the Old Red Sandstone omitted.

The eastern and western coasts of Scotland, which lie to the north of the Friths of Forth and Clyde, together with the southern flank of the Grampians and the northern coast of Sutherland and Caithness, appear to have been girdled at some early period by immense continuous beds of Old Red Sandstone. At a still earlier time, the girdle seems to have formed an entire mantle, which covered the enclosed tract from side to side. The interior is composed of what, after the elder geologists, I shall term primary rocks—porphyries, granites, gneisses, and micaceous schists; and this central nucleus, as it now exists, seems set in a sandstone frame. The southern bar of the frame is still entire: it stretches along the Grampians from Stonehaven to the Frith of Clyde. The northern bar is also well nigh entire: it runs unbroken along the whole northern coast of Caithness, and studs, in three several localities, the northern coast of Sutherland, leaving breaches of no very considerable extent between. On the east, there are considerable gaps, as along the shores of Aberdeenshire.[D] The sandstone, however, appears at Gamrie, in the county of Banff, in a line parallel to the coast, and, after another interruption, follows the coast of the Moray Frith far into the interior of the great Caledonian valley, and then running northward along the shores of Cromarty, Ross, and Sutherland, joins, after another brief interruption, the northern bar at Caithness.

[D] The progress of discovery has shown, since this passage was written, that these gaps are not quite so considerable as I had supposed. The following paragraph, which appeared in July, 1843, in an Aberdeen paper, bears directly on the point, and is worthy of being preserved:—

"ARTESIAN WELL.

"The greatest of these interesting works yet existing in Aberdeen has just been successfully completed at the tape-works of Messrs. Milne, Low, and Co., Woolmanhill. The bore is 8 inches in diameter, and 250 feet 9 inches deep. It required nearly eleven months' working to complete the excavation.

"In its progress, the following strata were cut through in succession:—

"The temperature of the water at the bottom of the well, when completed, was found to be within a fraction of 50° Fahrenheit, and the average temperature of the locality, deduced from twenty-three years' observation, by the late George limes, F. R. S., is 47° 1: hence, nearly 3 degrees of increase appear as the effects of central heat. The supply of water obtained is excellent in quality, and sufficient in quantity for all the purposes of the works. Such an opportunity of investigating the geology of the locality can but rarely occur; and, in the present instance, the proprietor and managers afforded every facility to scientific inquirers for conducting examinations. To make the bearings of the case clear and simple, the following is quoted from Mr. Miller's work on the Old Red Sandstone. [The writer here quotes the above passage, and then proceeds.] Mr. Miller will be glad to learn, that though the convulsions of nature have shattered the 'frame' along the shores of Aberdeenshire, yet the fragments are not lost, as will be seen from the section above described; they are here reposing in situ under the accumulated debris of uncounted ages—chiefly the 'boulder clay,' and sedimentary deposits of the Dee and Don, during a period when they mingled their waters in the basin in which Aberdeen now stands. The primary rocks—the settings—our granites, of matchless beauty stand out in bold relief a mile or two westward from the sea-coast. Within this year or two, the 'Old Red' has been discovered at Devanha, Union Grove, Huntly Street, Glenburnie, Balgownie, and various other localities to the northward. Hence it may reasonably be inferred, that our fragment of the 'frame' envelops the primary rocks under our city, and along the coast for a considerable distance between the Dee and the Buchaness."—Aberdeen Constitutional.

The western bar has also its breaches towards the south; but it stretches, almost without interruption, for about a hundred miles, from the near neighborhood of Cape Wrath to the southern extremity of Applecross; and though greatly disturbed and overflown by the traps of the inner Hebrides, it can be traced by occasional patches on towards the southern bar. It appears on the northern shore of Loch Alsh, on the eastern shore of Loch Eichart, on the southern shore of Loch Eil, on the coast and islands near Oban, and on the east coast of Arran. Detached hills and island-like patches of the same formation occur in several parts of the interior, far within the frame or girdle. It caps some of the higher summits in Sutherlandshire; it forms an oasis of sandstone among the primary districts of Strathspey; it rises on the northern shores of Loch Ness in an immense mass of conglomerate, based on a small-grained, red granite, to a height of about three thousand feet over the level; and on the north-western coast of Ross-shire it forms three immense insulated hills, of at least no lower altitude, that rest unconformably on a base of gneiss.

There appear every where in connection with these patches and eminences, and with the surrounding girdle, marks of vast denudation. I have often stood fronting the three Ross-shire hills[E] at sunset in the finer summer evenings, when the clear light threw the shadows of their gigantic, cone-like forms far over the lower tract, and lighted up the lines of their horizontal strata, till they showed like courses of masonry in a pyramid. They seem at such times as if colored by the geologist, to distinguish them from the surrounding tract, and from the base on which they rest as on a common pedestal. The prevailing gneiss of the district reflects a cold, bluish hue, here and there speckled with white, where the weathered and lichened crags of intermingled quartz rock jut out on the hill-sides from among the heath. The three huge pyramids, on the contrary, from the deep red of the stone, seem flaming in purple. There spreads all around a wild and desolate landscape of broken and shattered hills, separated by deep and gloomy ravines, that seem the rents and fissures of a planet in ruins, and that speak distinctly of a period of convulsion, when upheaving fires from the abyss, and ocean currents above, had contended in sublime antagonism, the one slowly elevating the entire tract, the other grinding it down and sweeping it away. I entertain little doubt that, when this loftier portion of Scotland, including the entire Highlands, first presented its broad back over the waves, the upper surface consisted exclusively, from the one extremity to the other—from Benlomond to the Maidenpaps of Caithness—of a continuous tract of Old Red Sandstone; though, ere the land finally emerged, the ocean currents of ages had swept it away, all except in the lower and last-raised borders, and in the detached localities, where it still remains, as in the pyramidal hills of western Ross-shire, to show the amazing depth to which it had once overlaid the inferior rocks. The Old Red Sandstone of Morvheim, in Caithness, overlooks all the primary hills of the district, from an elevation of three thousand five hundred feet.

[E] Suil Veinn, Coul Beg, and Coul More.

The depth of the system, on both the eastern and western coasts of Scotland, is amazingly great—how great, I shall not venture to say. There are no calculations more doubtful than those of the geologist. The hill just instanced (Morvheim) is apparently composed from top to bottom of what in Scotland forms the lowest member of the system—a coarse conglomerate; and yet I have nowhere observed this inferior member, when I succeeded in finding a section of it directly vertical, more than a hundred yards in thickness—less than one tenth the height of the hill. It would be well nigh as unsafe to infer that the three thousand five hundred feet of altitude formed the real thickness of the conglomerate, as to infer that the thickness of the lead which covers the dome of St. Paul's is equal to the height of the dome. It is always perilous to estimate the depth of a deposit by the height of a hill that seems externally composed of it, unless, indeed, like the pyramidal hills of Ross-shire, it be unequivocally a hill dug out by denudation, as the sculptor digs his eminences out of the mass. In most of our hills, the upheaving agency has been actively at work, and the space within is occupied by an immense nucleus of inferior rock, around which the upper formation is wrapped like a caul, just as the vegetable mould or the diluvium wraps up this superior covering in turn. One of our best known Scottish mountains—the gigantic Ben Nevis—furnishes an admirable illustration of this latter construction of hill. It is composed of three zones or rings of rock, the one rising over and out of the other, like the cases of an opera-glass drawn out. The lower zone is composed of gneiss and mica-slate, the middle zone of granite, the terminating zone of porphyry. The elevating power appears to have acted in the centre, as in the well-known case of Jorullo, in the neighborhood of the city of Mexico, where a level tract four square miles in extent rose, about the middle of the last century, into a high dome of more than double the height of Arthur's Seat.[F] In the formation of our Scottish mountain, the gneiss and mica-slate of the district seem to have been upheaved, during the first period of Plutonic action in the locality, into a rounded hill of moderate altitude, but of huge base. The upheaving power continued to operate—the gneiss and mica-slate gave way a-top—and out of this lower dome there arose a higher dome of granite, which, in an after and terminating period of the internal activity, gave way in turn to yet a third and last dome of porphyry. Now, had the elevating forces ceased to operate just ere the gneiss and mica-slate had given way, we would have known nothing of the interior nucleus of granite—had they ceased just ere the granite had given way, we would have known nothing of the yet deeper nucleus of porphyry; and yet the granite and the porphyry would assuredly have been there. Nor could any application of the measuring rule to the side of the hill have ascertained the thickness of its outer covering—the gneiss and the mica schist. The geologists of the school of Werner used to illustrate what we may term the anatomy of the earth, as seen through the spectacles of their system, by an onion and its coats: they represented the globe as a central nucleus, encircled by concentric coverings, each covering constituting a geological formation. The onion, through the introduction of a better school, has become obsolete as an illustration; but to restore it again, though for another purpose, we have merely to cut it through the middle, and turn downwards the planes formed by the knife. It then represents, with its coats, hills such as we describe—hills such as Ben Nevis, ere the granite had perforated the gneiss, or the porphyry broken through the granite.

[F] It is rarely that the geologist catches a hill in the act of forming, and hence the interest of this well-attested instance. From the period of the discovery of America to the middle of the last century, the plains of Jorullo had undergone no change of surface, and the seat of the present hill was covered by plantations of indigo and sugar-cane, when, in June, 1759, hollow sounds were heard, and a succession of earthquakes continued for sixty days, to the great consternation of the inhabitants. After the cessation of these, and in a period of tranquillity, on the 28th and 29th of September, a horrible subterranean noise was again heard, and a tract four square miles in extent rose up in the shape of a dome or bladder, to the height of sixteen hundred and seventy feet above the original level of the plain. The affrighted Indians fled to the mountains; and from thence looking down on the phenomenon, saw flames issuing from the earth for miles around the newly-elevated hill, and the softened surface rising and falling like that of an agitated sea, and opening into numerous rents and fissures. Two brooks which had watered the plantations precipitated themselves into the burning chasms. The scene of this singular event was visited by Humboldt about the beginning of the present century. At that period, the volcanic agencies had become comparatively quiescent; the hill, however, retained its original altitude; a number of smaller hills had sprung up around it; and the traveller found the waters of the engulfed rivulets escaping at a high temperature from caverns charged with sulphureous vapors and carbonic acid gas. There wore inhabitants of the country living at the time who were more than twenty years older than the hill of Jorullo, and who had witnessed its rise.

If it be thus unsafe, however, to calculate on the depth of deposits by the altitude of hills, it is quite as unsafe for the geologist, who has studied a formation in one district, to set himself to criticise the calculations of a brother geologist by whom it has been studied in a different and widely-separated district. A deposit in one locality may be found to possess many times the thickness of the same deposit in another. There are exposed, beside the Northern and Southern Sutors of Cromarty, two nearly vertical sections of the coarse conglomerate bed, which forms, as I have said, in the north of Scotland, the base of the Old Red System, and which rises to so great an elevation in the mountain of Morvheim. The sections are little more than a mile apart; and yet, while the thickness of this bed in the one does not exceed one hundred feet, that of the same bed in the other somewhat exceeds two hundred feet. More striking still—under the Northern Sutor, the entire Geology of Caithness, with all its vast beds, and all its numerous fossils, from the granitic rock of the Ord hill, the southern boundary of the county, to the uppermost sandstones of Dunnet-head, its extreme northern corner, is exhibited in a vertical section not more than three hundred yards in extent. And yet so enormous is the depth of the deposit in Caithness, that it has been deemed by a very superior geologist to represent three entire formations—the Old Red System, by its unfossiliferous, arenaceous, and conglomerate beds; the Carboniferous System, by its dark-colored middle schists, abounding in bitumen and ichthyolites; and the New Red Sandstone, by the mottled marls and mouldering sandstones that overlie the whole.[G] A slight sketch of the Geology of Caithness may not be deemed uninteresting. This county includes, in the state of greatest development any where yet known, that fossiliferous portion of the Old Red Sandstone which I purpose first to describe, and which will yet come to be generally regarded as an independent formation, as unequivocally characterized by its organic remains as the formations either above or below it.

[G] Dr. Hibbert, whose researches among the limestones of Burdie House have been of such importance to Geology, was of this opinion. I find it also expressed in the admirable geological appendix affixed by the Messrs. Anderson to their Guide to the Highlands and Islands of Scotland. "No beds of real coal," say these gentlemen, "have been discovered in Caithness; and it would thus appear that the middle schistose system of the county, containing the fossil fish, is in geological character and position intermediate between the Old and New Red Sandstone formations, but not identical with the Carboniferous Limestone, or the true Coal Measures, although probably occupying the place of one or other of them."—p. 198.

The county of Sutherland stretches across the island from the German to the Atlantic Ocean, and presents, throughout its entire extent,—except where a narrow strip of the Oolitic formation runs along its eastern coast, and a broken belt of Old Red Sandstone tips its capes and promontories on the west,—a broken and tumultuous sea of primary hills. Scarce any of our other Scottish counties are so exclusively Highland, nor are there any of them in which the precipices are more abrupt, the valleys more deep, the rivers more rapid, or the mountains piled into more fantastic groups and masses. The traveller passes into Caithness, and finds himself surrounded by scenery of an aspect so entirely dissimilar, that no examination of the rocks is necessary to convince him of a geological difference of structure. An elevated and uneven plain spreads around and before him, league beyond league, in tame and unvaried uniformity,—its many hollows darkened by morasses, over which the intervening eminences rise in the form rather of low moory swellings, than of hills,—its coasts walled round by cliffs of gigantic altitude, that elevate the district at one huge stride from the level of the sea, and skirted by vast stacks and columns of rock, that stand out like the advanced pickets of the land amid the ceaseless turmoil of the breakers. The district, as shown on the map, presents nearly a triangular form—the Pentland Frith and the German Ocean describing two of its sides, while the base is formed by the line of boundary which separates it from the county of Sutherland.

Now, in a geological point of view, this angle may be regarded as a vast pyramid, rising perpendicularly from the basis furnished by the primary rocks of the latter county, and presenting newer beds and strata as we ascend, until we reach the apex. The line from south to north in the angle—from Morvheim to Dunnet-head—corresponds to the line of ascent from the top to the bottom of the pyramid. The first bed, reckoning from the base upwards,—the ground tier of the masonry, if I may so speak,—is the great conglomerate. It runs along the line of boundary from sea to sea,—from the Ord of Caithness on the east, to Portskerry on the north; and rises, as it approaches the primary hills of Sutherland, into a lofty mountain chain of bold and serrated outline, which attains its greatest elevation in the hill of Morvheim. This great conglomerate bed, the base of the system, is represented in the Cromarty section, under the Northern Sutor, by a bed two hundred and fifteen feet in thickness. The second tier of masonry in the pyramid, and which also runs in a nearly parallel line from sea to sea, is composed mostly of a coarse red and yellowish sandstone, with here and there beds of pebbles enclosed, and here and there deposits of green earth and red marl. It has its representative in the Cromarty section, in a bed of red and yellow arenaceous stone, one hundred and fourteen feet six inches in thickness. These two inferior beds possess but one character,—they are composed of the same materials, with merely this difference, that the rocks which have been broken into pebbles for the construction of the one, have been ground into sand for the composition of the other. Directly over them, the middle portion of the pyramid is occupied by an enormous deposit of dark-colored bituminous schist, slightly micaceous, calcareous, or semi-calcareous,—here and there interlaced with veins of carbonate of lime,—here and there compact and highly siliceous,—and bearing in many places a mineralogical character difficult to be distinguished from that at one time deemed peculiar to the harder grauwacke schists. The Caithness flagstones, so extensively employed in paving the footways of our larger towns, are furnished by this immense middle tier or belt, and represent its general appearance. From its lowest to its highest beds it is charged with fossil fish and obscure vegetable impressions; and we find it represented in the Cromarty section by alternating bands of sandstones, stratified clays, and bituminous and nodular limestones, which form altogether a bed three hundred and fifty-five feet in thickness; nor does this bed lack its organisms, animal and vegetable, generically identical with those of Caithness. The apex of the pyramid is formed of red mouldering sandstones and mottled marls, which exhibit their uppermost strata high over the eddies of the Pentland Frith, in the huge precipices of Dunnet-head, and which are partially represented in the Cromarty section by an unfossiliferous sandstone bed of unascertained thickness; but which can be traced for about eighty feet from the upper limestones and stratified clays of the middle member, until lost in overlying beds of sand and shingle.

I am particular, at the risk, I am afraid, of being tedious, in thus describing the Geology of this northern county, and of the Cromarty section, which represents and elucidates it. They illustrate more than the formations of two insulated districts: they represent also a vast period of time in the history of the globe. The pyramid, with its three huge bars, its foundations of granitic rock, its base of red conglomerate, its central band of dark-colored schist, and its lighter tinted apex of sandstone, is inscribed from bottom to top, like an Egyptian obelisk, with a historical record. The upper and lower sections treat of tempests and currents—the middle is "written within and without" with wonderful narratives of animal life; and yet the whole, taken together, comprises but an earlier portion of that chronicle of existences and events furnished by the Old Red Sandstone. It is, however, with this earlier portion that my acquaintance is most minute.

My first statement regarding it must be much the reverse of the borrowed one with which this chapter begins. The fossils are remarkably numerous, and in a state of high preservation. I have a hundred solid proofs by which to establish the truth of the assertion, within less than a yard of me. Half my closet walls are covered with the peculiar fossils of the Lower Old Red Sandstone; and certainly a stranger assemblage of forms have rarely been grouped together;—creatures whose very type is lost, fantastic and uncouth, and which puzzle the naturalist to assign them even their class;—boat-like animals, furnished with oars and a rudder;—fish plated over, like the tortoise, above and below, with a strong armor of bone, and furnished with but one solitary rudder-like fin; other fish less equivocal in their form, but with the membranes of their fins thickly covered with scales;—creatures bristling over with thorns; others glistening in an enamelled coat, as if beautifully japanned—the tail, in every instance among the less equivocal shapes, formed not equally, as in existing fish, on each side the central vertebral column, but chiefly on the lower side—the column sending out its diminished vertebræ to the extreme termination of the fin. All the forms testify of a remote antiquity—of a period whose "fashions have passed away." The figures on a Chinese vase or an Egyptian obelisk are scarce more unlike what now exists in nature, than the fossils of the Lower Old Red Sandstone.

Geology, of all the sciences, addresses itself most powerfully to the imagination, and hence one main cause of the interest which it excites. Ere setting ourselves minutely to examine the peculiarities of these creatures, it would be perhaps well that the reader should attempt realizing the place of their existence, and relatively the time—not of course with regard to dates and eras, for the geologist has none to reckon by, but with respect to formations. They were the denizens of the same portion of the globe which we ourselves inhabit, regarded not as a tract of country, but as a piece of ocean crossed by the same geographical lines of latitude and longitude. Their present place of sepulture in some localities, had there been no denudation, would have been raised high over the tops of our loftiest hills—at least a hundred feet over the conglomerates which form the summit of Morvheim, and more than a thousand feet over the snow-capped Ben Wyvis. Geology has still greater wonders. I have seen belemnites of the Oolite—comparatively a modern formation—which had been dug out of the sides of the Himalaya mountains, seventeen thousand feet over the level of the sea. But let us strive to carry our minds back, not to the place of sepulture of these creatures, high in the rocks,—though that I shall afterwards attempt minutely to describe,—but to the place in which they lived, long ere the sauroid fishes of Burdie House had begun to exist, or the corallines of the mountain limestone had spread out their multitudinous arms in a sea gradually shallowing, and out of which the land had already partially emerged.

A continuous ocean spreads over the space now occupied by the British islands: in the tract covered by the green fields and brown moors of our own country, the bottom, for a hundred yards downwards, is composed of the debris of rolled pebbles and coarse sand intermingled, long since consolidated into the lower member of the Old Red Sandstone; the upper surface is composed of banks of sand, mud, and clay; and the sea, swarming with animal life, flows over all. My present object is to describe the inhabitants of that sea.

Of these, the greater part yet discovered have been named by Agassiz, the highest authority as an ichthyologist in Europe or the world, and in whom the scarcely more celebrated Cuvier recognized a naturalist in every respect worthy to succeed him. The comparative amount of the labors of these two great men in fossil ichthyology, and the amazing acceleration which has taken place within the last few years in the progress of geological science, are illustrated together, and that very strikingly, by the following interesting fact—a fact derived directly from Agassiz himself, and which must be new to the great bulk of my readers. When Cuvier closed his researches in this department, he had named and described, for the guidance of the geologist, ninety-two distinct species of fossil fish; nor was it then known that the entire geological scale, from the Upper Tertiary to the Grauwacke inclusive, contained more. Agassiz commenced his labors; and, in a period of time little exceeding fourteen years, he has raised the number of species from ninety-two to sixteen hundred. And this number, great as it is, is receiving accessions almost every day. In his late visit to Scotland, he found eleven new species, and one new genus, in the collection of Lady Gumming of Altyre, all from the upper beds of that lower member of the Old Red Sandstone represented by the dark-colored schists and inferior sandstones of Caithness. He found forty-two new species more in a single collection in Ireland, furnished by the Mountain Limestone of Armagh.

Some of my humbler readers may possibly be repelled by his names; they are, like all names in science, unfamiliar in their respect to mere English readers, just because they are names not for England alone, but for England and the world. I am assured, however, that they are all composed of very good Greek, and picturesquely descriptive of some peculiarity in the fossils they designate. One of his ichthyolites, with a thorn or spine in each fin, bears the name of Acanthodes, or thorn-like; another with a similar mechanism of spines attached to the upper part of the body, and in which the pectoral or hand-fins are involved, has been designated the Cheiracanthus, or thorn-hand; a third covered with curiously-fretted scales, has been named the Glyptolepis, or carved-scale; and a fourth, roughened over with berry-like tubercles, that rise from strong osseous plates, is known as the Coccosteus, or berry-on-bone. And such has been his principle of nomenclature. The name is a condensed description. But though all his names mean something, they cannot mean a great deal; and as learned words repel unlearned readers, I shall just take the liberty of reminding mine of the humbler class, that there is no legitimate connection between Geology and the dead languages. The existences of the Old Red Sandstone had lived for ages, and had been dead for myriads of ages, ere there was Greek enough in the world to furnish them with names. There is no working-man, if he be a person of intelligence and information, however unlearned, in the vulgar acceptation of the phrase, who may not derive as much pleasure and enlargement of idea from the study of Geology, and acquaint himself as minutely with its truths, as if possessed of all the learning of Bentley.

[CHAPTER III.]

Lamarck's Theory of Progression illustrated.—Class of Facts which give Color to it.—The Credulity of Unbelief.—M. Maillet and his Fish-birds.—Gradation not Progress.—Geological Argument.—The Present incomplete without the Past.—Intermediate Links of Creation.—Organisms of the Lower Old lied Sandstone.—The Pterichthys.—Its first Discovery.—Mr. Murchison's Decision regarding it.—Confirmed by that of Agassiz.—Description.—The several Varieties of the Fossil yet discovered.—Evidence of Violent Death in the Attitudes in which they are found.—The Coccosteus of the Lower Old Red.—Description.—Gradations from Crustacea to Fishes.—Habits of the Coccosteus.—Scarcely any Conception too extravagant for Nature to realize.

Mr. Lyell's brilliant and popular work, The Principles of Geology, must have introduced to the knowledge of most of my readers the strange theories of Lamarck. The ingenious foreigner, on the strength of a few striking facts, which prove that, to a certain extent, the instincts of species may be improved and heightened, and their forms changed from a lower to a higher degree of adaptation to their circumstances, has concluded that there is a natural progress from the inferior orders of being towards the superior; and that the offspring of creatures low in the scale in the present time, may hold a much higher place in it, and belong to different and nobler species, a few thousand years hence. The descendants of the ourang-outang, for instance, may be employed in some future age in writing treatises on Geology, in which they shall have to describe the remains of the quadrumana as belonging to an extinct order. Lamarck himself, when bearing home in triumph with him the skeleton of some huge salamander or crocodile of the Lias, might indulge, consistently with his theory, in the pleasing belief that he had possessed himself of the bones of his grandfather—a grandfather removed, of course, to a remote degree of consanguinity, by the intervention of a few hundred thousand great-greats. Never yet was there a fancy so wild and extravagant but there have been men bold enough to dignify it with the name of philosophy, and ingenious enough to find reasons for the propriety of the name.

The setting-dog is taught to set; he squats down and points at the game; but the habit is an acquired one—a mere trick of education. What, however, is merely acquired habit in the progenitor, is found to pass into instinct in the descendant: the puppy of the setting-dog squats down and sets untaught—the educational trick of the parent is mysteriously transmuted into an original principle in the offspring. The adaptation which takes place in the forms and constitution of plants and animals, when placed in circumstances different from their ordinary ones, is equally striking. The woody plant of a warmer climate, when transplanted into a colder, frequently exchanges its ligneous stem for a herbaceous one, as if in anticipation of the killing frosts of winter; and, dying to the ground at the close of autumn, shoots up again in spring. The dog, transported from a temperate into a frigid region, exchanges his covering of hair for a covering of wool; when brought back again to his former habitat, the wool is displaced by the original hair. And hence, and from similar instances, the derivation of an argument, good so far as it goes, for changes in adaptation to altered circumstances of the organization of plants and animals, and for the unprovability of instinct. But it is easy driving a principle too far. The elasticity of a common bow, and the strength of an ordinary arm, are fully adequate to the transmission of an arrow from one point of space to another point a hundred yards removed; but he would be a philosopher worth looking at, who would assert that they were equally adequate for the transmission of the same arrow from points removed, not by a hundred yards, but by a hundred miles. And such, but still more glaring, has been the error of Lamarck. Fie has argued on this principle of improvement and adaptation—which, carry it as far as we rationally may, still leaves the vegetable a vegetable, and the dog a dog—that, in the vast course of ages, inferior have risen into superior natures, and lower into higher races; that molluscs and zoöphytes have passed into fish and reptiles, and fish and reptiles into birds and quadrupeds; that unformed, gelatinous bodies, with an organization scarcely traceable, have been metamorphosed into oaks and cedars; and that monkeys and apes have been transformed into human creatures, capable of understanding and admiring the theories of Lamarck. Assuredly there is no lack of faith among infidels; their "vaulting" credulity o'erleaps revelation, and "falls on the other side." One of the first geological works I ever read was a philosophical romance, entitled Telliamed, by a M. Maillet, an ingenious Frenchman of the days of Louis XV. This Maillet was by much too great a philosopher to credit the scriptural account of Noah's flood; and yet he could believe, like Lamarck, that the whole family of birds had existed at one time as fishes, which, on being thrown ashore by the waves, had got feathers by accident; and that men themselves are but the descendants of a tribe of sea-monsters, who, tiring of their proper element, crawled up the beach one sunny morning, and, taking a fancy to the land, forgot to return.[H]

[H] Few men could describe better than Maillet. His extravagances are as amusing as those of a fairy tale, and quite as extreme. Take the following extract as an instance:—

"Winged or flying fish, stimulated by the desire of prey, or the fear of death, or pushed near the shore by the billows, have fallen among reeds or herbage, whence it was not possible for them to resume their flight to the sea, by means of which they had contracted their first facility of flying. Then their fins, being no longer bathed in the sea-water, were split, and became warped by their dryness. While they found, among the reeds and herbage among which they fell, any aliments to support them, the vessels of their fins, being separated, were lengthened and clothed with beards, or, to speak more justly, the membranes, which before kept them adherent to each other, were metamorphosed. The beard formed of these warped membranes was lengthened. The skin of these animals was insensibly covered with a down of the same color with the skin, and this down gradually increased. The little wings they had under their belly, and which, like their wings, helped them to walk in the sea, became feet, and served them to walk on land. There were also other small changes in their figure. The beak and neck of some were lengthened, and those of others shortened. The conformity, however, of the first figure subsists in the whole, and it will be always easy to know it. Examine all the species of fowls, large and small, even those of the Indies, those which are tufted or not, those whose feathers are reversed, such as we see at Damietta—that is to say, whose plumage runs from the tail to the head—and you will find species of fish quite similar, scaly or without scales. All species of parrots, whose plumages are so different, the rarest and the most singular-marked birds, are, conformable to fact, painted like them with black, brown, gray, yellow, green, red, violet color, and those of gold and azure; and all this precisely in the same parts where the plumages of those birds are diversified in so curious a manner."—Telliamed, p. 224, ed. 1750.

"How easy," says this fanciful writer, "is it to conceive the change of a winged fish, flying at times through the water, at times through the air, into a bird flying always through the air!" It is a law of nature, that the chain of being, from the lowest to the highest form of life, should be, in some degree, a continuous chain; that the various classes of existence should shade into one another, so that it often proves a matter of no little difficulty to point out the exact line of demarcation where one class or family ends, and another class or family begins. The naturalist passes from the vegetable to the animal tribes, scarcely aware, amid the perplexing forms of intermediate existence, at what point he quits the precincts of the one to enter on those of the other. All the animal families have, in like manner, their connecting links; and it is chiefly out of these that writers such as Lamarck and Maillet construct their system. They confound gradation with progress. Geoffrey Hudson was a very short man, and Goliath of Gath a very tall one, and the gradations of the human stature lie between. But gradation is not progress; and though we find full-grown men of five feet, five feet six inches, six feet, and six feet and a half, the fact gives us no earnest whatever that the race is rising in stature, and that at some future period the average height of the human family will be somewhat between ten and eleven feet. And equally unsolid is the argument, that from a principle of gradation in races would deduce a principle of progress in races. The tall man of six feet need entertain quite as little hope of rising into eleven feet as the short man of five; nor has the fish that occasionally flies any better chance of passing into a bird than the fish that only swims.

Geology abounds with creatures of the intermediate class: there are none of its links more numerous than its connecting links; and hence its interest, as a field of speculation, to the assertors of the transmutation of races. But there is a fatal incompleteness in the evidence, that destroys its character as such. It supplies in abundance those links of generic connection, which, as it were, marry together dissimilar races; but it furnishes no genealogical link to show that the existences of one race derive their lineage from the existences of another. The scene shifts, as we pass from formation to formation; we are introduced in each to a new dramatis personæ; and there exist no such proofs of their being at once different and yet the same, as those produced in the Winter's Tale, to show that the grown shepherdess of the one scene is identical with the exposed infant of the scene that went before. Nay, the reverse is well nigh as strikingly the case, as if the grown shepherdess had been introduced into the earlier scenes of the drama, and the child into its concluding scenes.

The argument is a very simple one. Of all the vertebrata, fishes rank lowest, and in geological history appear first. We find their remains in the Upper and Lower Silurians, in the Lower, Middle, and Upper Old Red Sandstone, in the Mountain Limestone, and in the Coal Measures; and in the latter formation the first reptiles appear. Fishes seem to have been the master existences of two great systems, mayhap of three, ere the age of reptiles began. Now fishes differ very much among themselves: some rank nearly as low as worms, some nearly as high as reptiles; and if fish could have risen into reptiles, and reptiles into mammalia, we would necessarily expect to find lower orders of fish passing into higher, and taking precedence of the higher in their appearance in point of time, just as in the Winter's Tale we see the infant preceding the adult. If such be not the case—if fish made their first appearance, not in their least perfect, but in their most perfect state—not in their nearest approximation to the worm, but in their nearest approximation to the reptile—there is no room for progression, and the argument falls. Now it is a geological fact, that it is fish of the higher orders that appear first on the stage, and that they are found to occupy exactly the same level during the vast period represented by five succeeding formations. There is no progression. If fish rose into reptiles, it must have been by sudden transformation—it must have been as if a man who had stood still for half a lifetime should bestir himself all at once, and take seven leagues at a stride. There is no getting rid of miracle in the case—there is no alternative between creation and metamorphosis. The infidel substitutes progression for Deity; Geology robs him of his god.

But no man who enters the geological field in quest of the wonderful, need pass in pursuit of his object from the true to the fictitious. Does the reader remember how, in Milton's sublime figure, the body of Truth is represented as hewn in pieces, and her limbs scattered over distant regions, and how her friends and disciples have to go wandering all over the world in quest of them? There is surely something very wonderful in the fact, that, in uniting the links of the chain of creation into an unbroken whole, we have in like manner to seek for them all along the scale of the geologist;—some we discover among the tribes first annihilated—some among the tribes that perished at a later period—some among the existences of the passing time. We find the present incomplete without the past—the recent without the extinct. There are marvellous analogies which pervade the scheme of Providence, and unite, as it were, its lower with its higher parts. The perfection of the works of Deity is a perfection entire in its components; and yet these are not contemporaneous, but successive: it is a perfection which includes the dead as well as the living, and bears relation, in its completeness, not to time, but to eternity.

We find the organisms of the Old Red Sandstone supplying an important link, or, rather, series of links, in the ichthyological scale, which are wanting in the present creation, and the absence of which evidently occasions a wide gap between the two grand divisions or series of fishes—the bony and the cartilaginous. Of this, however, more anon. Of all the organisms of the system, one of the most extraordinary, and the one in which Lamarck would have most delighted, is the Pterichthys, or winged fish, an ichthyolite which the writer had the pleasure of introducing to the acquaintance of geologists nearly three years ago, but which he first laid open to the light about seven years earlier. Had Lamarck been the discoverer, he would unquestionably have held that he had caught a fish almost in the act of wishing itself into a bird. There are wings which want only feathers, a body which seems to have been as well adapted for passing through the air as the water, and a tail by which to steer. And yet there are none of the fossils of the Old Red Sandstone which less resemble any thing that now exists than its Pterichthys. I fain wish I could communicate to the reader the feeling with which I contemplated my first-found specimen. It opened with a single blow of the hammer; and there, on a ground of light-colored limestone, lay the effigy of a creature fashioned apparently out of jet, with a body covered with plates, two powerful looking arms, articulated at the shoulders, a head as entirely lost in the trunk as that of the ray or the sun-fish, and a long, angular tail. My first-formed idea regarding it was, that I had discovered a connecting link between the tortoise and the fish—the body much resembles that of a small turtle; and why, I asked, if one formation gives us sauroid fishes, may not another give us chelonian ones? or if in the Lias we find the body of the lizard mounted on the paddles of the whale, why not find in the Old Red Sandstone the body of the tortoise mounted in a somewhat similar manner? The idea originated in error; but as it was an error which not many naturalists could have corrected at the time, it may be deemed an excusable one, more especially by such of my readers as may have seen well-preserved specimens of the creature, or who examine the subjoined prints. (Nos. I. and II.) I submitted some of my specimens to Mr. Murchison, at a time when that gentleman was engaged among the fossils of the Silurian System, and employed on his great work, which has so largely served to extend geological knowledge regarding those earlier periods in which animal life first began. He was much interested in the discovery: it furnished the geologist with additional data by which to regulate and construct his calculations, and added a new and very singular link to the chain of existence in its relation to human knowledge. Deferring to Agassiz, as the highest authority, he yet anticipated the decision of that naturalist regarding it, in almost every particular. I had inquired, under the influence of my first impression, whether it might not be considered as a sort of intermediate existence between the fish and the chelonian. He stated, in reply, that he could not deem it referrible to any family of reptiles; that, if not a fish, it approached more closely to the Crustacea than to any other class; and that he had little doubt Agassiz would pronounce it to be an ichthyolite of that ancient order to which the Cephalaspis belongs, and which seems to have formed a connecting link between crustacea and fishes.[I] The specimens submitted to Mr. Murchison were forwarded to Agassiz. They were much more imperfect than some which I have since disinterred; and to restore the entire animal from them would require powers such as those possessed by Cuvier in the past age, and by the naturalist of Neufchatel in the present. Broken as they were, however, Agassiz at once decided from them that the creature must have been a fish.

[I] The aborigines of South. America deemed it wonderful that the Europeans who first visited them should, without previous concert, agree in reading after the same manner the same scrap of manuscript, and in deriving the same piece of information from it. The writer experienced on this occasion a somewhat similar feeling. His specimens seemed written in a character cramp enough to suggest those doubts regarding original meaning which lead to various readings; but the geologist and the naturalist agreed in perusing them after exactly the same fashion—the one in London, the other in Neufchatel. Such instances give confidence in the findings of science. The decision of Mr. Murchison I subjoin in his own words—his numbers refer to various specimens of Pterichthys: "As to your fossils 1, 2, 3, we know nothing of them here, (London,) except that they remind me of the occipital fragments of some of the Caithness fishes. I do not conceive they can be referrible to any reptile; for, if not fishes, they more closely approach to crustaceans than to any other class. I conceive, however, that Agassiz will pronounce them to be fishes, which, together with the curious genus Cephalaspis of the Old Red Sandstone, form the connecting links between crustaceans and fishes. Your specimens remind one in several respects of the Cephalaspis."

PLATE I.

I have placed one of the specimens before me. Imagine the figure of a man rudely drawn in black on a gray ground, the head cut off at the shoulders, the arms spread at full, as in the attitude of swimming, the body rather long than otherwise, and narrowing from the chest downwards, one of the legs cut away at the hip-joint, and the other, as if to preserve the balance, placed directly under the centre of the figure, which it seems to support. Such, at a first glance, is the appearance of the fossil. The body was of very considerable depth, perhaps little less deep proportionally from back to breast than the body of the tortoise; the under part was flat; the upper rose towards the centre into a roof-like ridge; and both under and upper were covered with a strong armor of bony plates, which, resembling more the plates of the tortoise than those of the crustacean, received their accessions of growth at the edges or sutures. The plates on the under side are divided by two lines of suture, which run, the one longitudinally through the centre of the body, the other transversely, also through the centre; and they would cut one another at right angles, were there not a lozenge-shaped plate inserted at the point where they would otherwise meet. There are thus five plates on the lower or belly part of the animal. They are all thickly tubercled outside with wart-like prominences, (see [Plate I.], fig. 4;) the inner present appearances indicative of a bony structure. The plates on the upper side are more numerous and more difficult to describe, just as it would be difficult to describe the forms of the various stones which compose the ribbed and pointed roof of a Gothic cathedral, the arched ridge or hump of the back requiring, in a somewhat similar way, a peculiar form and arrangement of plates. The apex of the ridge is covered by a strong hexagonal plate, fitted upon it like a cap or helmet, and which nearly corresponds in place to the flat central plate of the under side. There runs around it a border of variously formed plates, that diminish in size and increase in number towards the head, and which are separated, like the pieces of a dissected map, by deep sutures. They all present the tubercled surface. The eyes are placed in front, on a prominence considerably lower than the roof-like ridge of the back; the mouth seems to have opened, as in many fishes, in the edge of the creature's snout, where a line running along the back would bisect a line running along the belly; but this part is less perfectly shown by my specimens than any other. The two arms, or paddles, are placed so far forward as to give the body a disproportionate and decapitated appearance. From the shoulder to the elbow, if I may employ the terms, there is a swelling, muscular appearance, as in the human arm; the part below is flattened, so as to resemble the blade of an oar, and terminates in a strong, sharp point. The tail—the one leg on which, as exhibited in one of my specimens, the creature seems to stand—is of considerable length, more than equal to a third of the entire figure, and of an angular form, the base representing the part attached to the body, and the apex its termination. It was covered with small tubercled, rhomboidal plates, like scales, (see [Plate I.], fig. 3;) and where the internal structure is shown, there are appearances of a vertebral column, with rib-like processes standing out at a sharp angle. The ichthyolite, in my larger specimens, does not much exceed seven inches in length; and I despatched one to Agassiz, rather more than two years ago, whose extreme length did not exceed an inch. Such is a brief, and, I am afraid, imperfect sketch of a creature whose very type seems no longer to exist. But for the purposes of the geologist, the descriptions of the graver far exceed those of the pen, and the accompanying prints will serve to supply all that may be found wanting in the text. Fig. 1, in [Plate I.], and fig. 2, in [Plate II.], are both restorations—the first of the upper, and the second of the under, part of the creature. It may, however, encourage the confidence of the naturalist, who for the first time looks upon forms so strange, to be informed that [Plate I.], with its two figures, was submitted to Agassiz during his recent brief stay in Edinburgh, and that he as readily recognized in it the species of the two kinds which it exhibits, as he had previously recognized the species of the originals in the limestone.

PLATE II.

Agassiz, in the course of his late visit to Scotland, found six species of the Pterichthys[J]—three of these, and the wings of a fourth, in the collection of the writer. The differences by which they are distinguished may be marked by even an unpractised eye, especially in the form of the bodies and wings. Some are of a fuller, some of a more elongated, form; in some the body resembles a heraldic shield, of nearly the ordinary shape and proportions; in others the shield stretches into a form not very unlike that of a Norway skiff, from the midships forward. In some of the varieties, too, the wings are long and comparatively slender; in others shorter, and of greater breadth: in some there is an inflection resembling the bend of an elbow; in others there is a continuous swelling from the termination to the shoulder, where a sudden narrowing takes place immediately over the articulation. I had inferred somewhat too hurriedly, though perhaps naturally enough, that these wings, or arms, with their strong sharp points and oar-like blades, had been at once paddles and spears—instruments of motion and weapons of defence; and hence the mistake of connecting the creature with the Chelonia. I am informed by Agassiz, however, that they were weapons of defence only, which, like the occipital spines of the river bull-head, were erected in moments of danger or alarm, and at other times lay close by the creature's side; and that the sole instrument of motion was the tail, which, when covered by its coat of scales, was proportionally of a somewhat larger size than the tail shown in the print, which, as in the specimens from whence it was taken, exhibits but the obscure and uncertain lineaments of the skeleton. The river bull-head, when attacked by an enemy, or immediately as it feels the hook in its jaws, erects its two spines at nearly right angles with the plates of the head, as if to render itself as difficult of being swallowed as possible. The attitude is one of danger and alarm; and it is a curious fact, to which I shall afterwards have occasion to advert, that in this attitude nine tenths of the Pterichthys of the Lower Old Red Sandstone are to be found. We read in the stone a singularly preserved story of the strong instinctive love of life, and of the mingled fear and anger implanted for its preservation—"The champions in distorted postures threat." It presents us, too, with a wonderful record of violent death falling at once, not on a few individuals, but on whole tribes.

[J] Agassiz now reckons ten distinct species of Pterichthys—P. arenatus, P. cancriformis, P. cornutus, P. major, P. Milleri, P. latus, P. oblongus, P. productus, P. testudinarius, and P. hydrophilus; of these, nine species belong to the Lower, and one—the Pterichthys hydrophilus—to the Upper Old Red Sandstone.

PLATE III.

Next to the Pterichthys of the Lower Old Red I shall place its contemporary the Coccosteus of Agassiz, a fish which, in some respects, must have somewhat resembled it. Both were covered with an armor of thickly tubercled bony plates, and both furnished with a vertebrated tail. The plates of the one, when found lying detached in the rock, can scarcely be distinguished from those of the other: there are the same marks, as in the plates of the tortoise, of accessions of growth at the edges—the same cancellated bony structure within, the same kind of tubercles without. The forms of the creatures themselves, however, were essentially different. I have compared the figure of the Pterichthys, as shown in some of my better specimens, to that of a man with the head cut off at the shoulders, one of the legs also wanting, and the arms spread to the full. The figure of the Coccosteus I would compare to a boy's kite. (See [Plate III.], fig. 1.) There is a rounded head, a triangular body, a long tail attached to the apex of the triangle, and arms thin and rounded where they attach to the body, and spreading out towards their termination like the ancient one-sided shovel which we see sculptured on old tombstones, or the rudder of an ancient galley.[K] The manner in which the plates are arranged on the head is peculiarly beautiful; but I am afraid I cannot adequately describe them. A ring of plates, like the ring-stones of an arch, runs along what may be called the hoop of the kite; the form of the keystone-plate is perfect; the shapes of the others are elegantly varied, as if for ornament; and what would be otherwise the opening of the arch, is filled up with one large plate, of an outline singularly elegant. A single plate, still larger than any of the others, covers the greater part of the creature's triangular body, to the shape of which it nearly conforms. It rises saddle-wise towards the centre: on the ridge there is a longitudinal groove ending in a perforation, a little over the apex, ([Plate III.], fig. 2;) two small lateral plates on either side fill up the base of the angle; and the long tail, with its numerous vertebral joints, terminates the figure.

[K] I have since ascertained that these seeming arms or paddles were simply plates of a peculiar form.

Does the reader possess a copy of Lyell's lately published elementary work, edition 1838? If so, let him first turn up the description of the Upper Silurian rocks, from Murchison, which occurs in page 459, and mark the form of the trilobite Asaphus caudatus, a fossil of the Wenlock formation. (See Sil. Sys., [Plate VII.]) The upper part, or head, forms a crescent; the body rises out of the concave with a sweep somewhat resembling that of a Gothic arch; the outline of the whole approximates to that of an egg, the smaller end terminating in a sharp point. Let him remark, further, that this creature was a crustaceous animal, of the crab or lobster class, and then turn up the brief description of the Old Red Sandstone in the same volume, page 454, and mark the form of the Cephalaspis, or buckler-head—a fish of a formation immediately over that in which the remains of the trilobite most abound. He will find that the fish and the crustacean are wonderfully alike. The fish is more elongated, but both possess the crescent-shaped head, and both the angular and apparently jointed body.[L] They illustrate admirably how two distinct orders may meet. They exhibit the points, if I may so speak, at which the plated fish is linked to the shelled crustacean. Now, the Coccosteus is a stage further on; it is more unequivocally a fish. It is a Cephalaspis with an articulated tail attached to the angular body, and the horns of the crescent-shaped head cut off.

[L] Really jointed in the case of the trilobite; only apparently so in that of the Cephalaspis. The body of the trilobite, like that of the lobster, was barred by transverse, oblong, overlapping plates, and between every two plates there was a joint; the body of the Cephalaspis, in like manner, was barred by transverse, oblong, overlapping scales, between which there existed no such joints. It is interesting to observe how nature, in thus bringing two such different classes as fishes and crustacea together, gives to the higher animal a sort of pictorial resemblance to the lower, in parts where the construction could not be identical without interfering with the grand distinctions of the classes.

Some of the specimens which exhibit this creature are exceedingly curious. In one, a coprolite still rests in the abdomen; and a common botanist's microscope shows it thickly speckled over with minute scales, the indigestible exuviæ of fish on which the animal had preyed. In the abdomen of another we find a few minute pebbles—just as pebbles are occasionally found in the stomach of the cod—which had been swallowed by the creature attached to its food. Is there nothing wonderful in the fact, that men should be learning at this time of day how the fishes of the Old Red Sandstone lived, and that there were some of them rapacious enough not to be over nice in their eating?

The under part of the creature is still very imperfectly known: it had its central lozenge-shaped plate, like that on the under side of the Pterichthys, but of greater elegance, (see [Plate III.], fig. 3,) round which the other plates were ranged. "What an appropriate ornament, if set in gold!" said Dr. Buckland, on seeing a very beautiful specimen of this central lozenge in the interesting collection of Professor Traill of Edinburgh,—"What an appropriate ornament for a lady geologist!" There are two marked peculiarities in the jaws of the Coccosteus, as shown in most of the specimens, illustrative of the lower part of the creature, which I have yet seen. The teeth, instead of being fixed in sockets, like those of quadrupeds and reptiles, or merely placed on the bone, like those of fish of the common varieties, seem to have been cut out of the solid, like the teeth of a saw or the teeth in the mandibles of the beetle, or in the nippers of the lobster, ([Plate III.], fig. 4;) and there appears to have been something strangely anomalous in the position of the jaws—something too anomalous, perhaps, to be regarded as proven by the evidence of the specimens yet found, but which may be mentioned with the view of directing attention to it. "Do not be deterred," said Agassiz, in the course of one of the interviews in which he obligingly indulged the writer of these chapters, who had mentioned to him that one of his opinions, just confirmed by the naturalist, had seemed so extraordinary that he had been almost afraid to communicate it,—"Do not be deterred, if you have examined minutely, by any dread of being deemed extravagant. The possibilities of existence run so deeply into the extravagant, that there is scarcely any conception too extraordinary for nature to realize." In all the more complete specimens which I have yet seen, the position of the jaws is vertical, not horizontal; and yet the creature, as shown by the tail, belonged unquestionably to the vertebrata. Now, though the mouths of the crustaceous animals, such as the crab and lobster, open vertically, and a similar arrangement obtains among the insect tribes, it has been remarked by naturalists, as an invariable condition of that higher order of animals distinguished by vertebral columns, that their mouths open horizontally. What I would remark as very extraordinary in the Coccosteus—not, however, in the way of directly asserting the fact, but merely by way of soliciting inquiry regarding it—is, that it seems to unite to a vertebral column a vertical mouth, thus forming a connecting link between two orders of existences, by conjoining what is at once their most characteristic and most dissimilar traits.[M]

[M] These statements regarding the character of the teeth and the position of the jaws of the Coccosteus have been challenged by very high authorities. I retain them, however, in this edition in their original form, as first made nearly six years ago. In at least two of my specimens of Coccosteus the teeth and jaw form unequivocally but one bone—a result, it is not improbable, of some after anchylosing process, but which still solicits inquiry as not yet definitely accounted for. The matter of fact in the case is certainly one which should be determined, not analogically, but on its own proper evidence, as furnished by good specimens. As for the remark regarding the probable position of the creature's jaws, it was ventured on at first, as the reader may perceive, with much hesitation, and must now be regarded as more doubtful than ever. Its repetition here, however, will, I trust, be regarded as simply indicative of a wish on the part of the writer, that the question be kept open just a little longer, and that further examination be made. There is certainly something very peculiar about the mouth of the Coccosteus not yet understood, and singularly formed plates, connected with it, which have not been introduced into any restoration, and the use of which in the economy of the animal seem wholly unknown. [1850.—I have at length found a very perfect specimen of the nether jaw of Coccosteus, and am prepared to show that it was of a character altogether unique. It had its two groups of from six to eight teeth, (exactly where, in the human subject, the molars are placed,) that seem to have acted on corresponding groups in the intermaxllaries, and two other groups of from three to five teeth placed at right angles with these, direct in the symphysis, and that seem to have acted on each other. But though these unique teeth of the symphysis formed a vertical line of mouth, it joined on at right angles to a transverse line of the ordinary type, as the upright stroke of the letter T joins on to the horizontal line a-top.] Fourth Edition.

I am acquainted with four species of Coccosteus—C. decipiens, C. cuspidatas, C. oblongus, and a variety not yet named; and many more species may yet be discovered.[N] Of all the existences of the formation, this curious fish seems to have been one of the most abundant. In a few square yards of rock I have laid open portions of the remains of a dozen different individuals belonging to two of the four species, the C. decipiens and C. cuspidatus, in the course of a single evening. None of the other kinds have yet been found at Cromarty. These two differed from each other in the proportions which their general bulk bore to their length—slightly, too, in the arrangement of their occipital plates. The Coccosteus latus, as the name implies, must have been by much a massier fish than the other; and we find the arch-like form of the plates which covered its head more complete: the plate representing the keystone rests on the saddle-shaped plate in the centre, and the plates representing the spring-stones of the arch exhibit a broader base. The accompanying print ([Plate III.]) represents the Coccosteus cuspidatus. The average length of the creature, including the tail, as shown in most of the Cromarty specimens, somewhat exceeded a foot. A few detached plates from Orkney, in the collection of Dr. Traill, must have belonged to an individual of fully twice that length.

[N] A fifth species has been named C. maximus.

[CHAPTER IV.]

The Elfin-fish of Gawin Douglas.—The Fish of the Old Red Sandstone scarcely less curious.—Place which they occupied indicated in the present Creation by a mere Gap.—Fish divided into two great Series, the Osseous and Cartilaginous.—Their distinctive Peculiarities.—Geological Illustration of Dr. Johnson's shrewd Objection to the Theory of Soame Jenyns.—Proofs of the intermediate Character of the Ichthyolites of the Old Red Sandstone.—Appearances which first led the Writer to deem it intermediate.—Confirmation by Agassiz.—The Osteolepis.—Order to which this Ichthyolite belonged.—Description.—Dipterus.—Diplopterus.—Cheirolepis.—Glyptolepis.

Has the reader ever heard of the "griesly fisch" and the "laithlie flood," described by that minstrel Bishop of Dunkeld "who gave rude Scotland Virgil's page?" Both fish and flood are the extravagances of a poet's dream. The flood came rolling through a wilderness of bogs and quagmires, under banks "dark as rocks the whilk the sey upcast." A skeleton forest stretched around, doddered and leafless; and through the "unblomit" and "barrant" trees

"The quhissling wind blew mony bitter blast;"

the whitened branches "clashed and clattered;" the "vile water rinnand o'erheid," and "routing as thonder," made "hideous trubil;" and to augment the uproar, the "griesly fisch," like the fish of eastern story, raised their heads amid the foam, and shrieked and yelled as they passed. "The grim monsters fordeafit the heiring with their sellouts;"—they were both fish and elves, and strangely noisy in the latter capacity; and the longer the poet listened, the more frightened he became. The description concludes, like a terrific dream, with his wanderings through the labyrinths of the dead forest, where all was dry and sapless above, and mud and marsh below, and with his exclamations of grief and terror at finding himself hopelessly lost in a scene of prodigies and evil spirits. And such was one of the wilder fancies in which a youthful Scottish poet of the days of Flodden indulged, ere taste had arisen to restrain and regulate invention.

Shall I venture to say, that the ichthyolites of the Old Red Sandstone have sometimes reminded me of the "fisch of the laithlie flood?" They were hardly less curious. We find them surrounded, like these, by a wilderness of dead vegetation, and of rocks upcast from the sea; and there are the foot-prints of storm and tempest around and under them. True, they must have been less noisy. Like the "griesly fisch," however, they exhibit a strange union of opposite natures. One of their families—that of the Cephalaspis—seems almost to constitute a connecting link, says Agassiz, between fishes and crustaceans. They had, also, their families of sauroid, or reptile fishes—and their still more numerous families that unite the cartilaginous fishes to the osseous. And to these last the explorer of the Lower Old Red Sandstone finds himself mainly restricted. The links of the system are all connecting links, separated by untold ages from that which they connect; so that, in searching for their representatives amid the existences of the present time, we find but the gaps which they should have occupied. And it is essentially necessary from this circumstance, in acquainting one's self with their peculiarities, to examine, if I may so express myself, the sides of these gaps,—the existing links at both ends to which the broken links should have pieced,—in short, all those more striking peculiarities of the existing disparted families which we find united in the intermediate families that no longer exist. Without some such preparation, the inquirer would inevitably share the fate of the poetical dreamer of Dunkeld, by losing his way in a labyrinth. In passing, therefore, with this object from the extinct to the recent, I venture to solicit, for a few paragraphs, the attention of the reader.

Fishes, the fourth great class in point of rank in the animal kingdom, and, in extent of territory, decidedly the first, are divided, as they exist in the present creation, into two distinct series—the osseous and the cartilaginous. The osseous embraces that vast assemblage which naturalists describe as "fishes properly so called," and whose skeletons, like those of mammalia, birds, and reptiles, are composed chiefly of a calcareous earth pervading an organic base. Hence the durability of their remains. In the cartilaginous series, on the contrary, the skeleton contains scarce any of this earth: it is a framework of indurated animal matter, elastic, semi-transparent, yielding easily to the knife, and, like all mere animal substances, inevitably subject to decay. I have seen the huge cartilaginous skeleton of a shark lost in a mass of putrefaction in less than a fortnight. I have found the minutest bones of the osseous ichthyolites of the Lias entire after the lapse of unnumbered centuries.

The two series do not seem to precede or follow one another in any such natural sequence as that in which the great classes of the animal kingdom are arranged. The mammifer takes precedence of the bird, the bird of the reptile, the reptile of the fish; there is progression in the scale—the arrangement of the classes is consecutive, not parallel. But in this great division there is no such progression; the osseous fish takes no precedence of the cartilaginous fish, or the cartilaginous, as a series, of the osseous. The arrangement is parallel, not consecutive; but the parallelism, if I may so express myself, seems to be that of a longer with a shorter line;—the cartilaginous fishes, though much less numerous in their orders and families than the other, stretch farther along the scale in opposite directions, at once rising higher and sinking lower than the osseous fishes. The cartilaginous order of the sturgeons,—a roe-depositing tribe, devoid alike of affection for their young, or of those attachments which give the wild beasts of the forest partners in their dens,—may be regarded as fully abreast of by much the greater part of the osseous fishes, in both their instincts and their organization. The family of the sharks, on the other hand, and some of the rays, rise higher, as if to connect the class of fish with the class immediately above it—that of reptiles. Many of them are viviparous, like the mammalia—attached, it is said, to their young, and fully equal even to birds in the strength of their connubial attachments. The male, in some instances, has been known to pine away and die when deprived of his female companion.[O] But then, on the other hand, the cartilaginous fishes, in some of their tribes, sink as low beneath the osseous as they rise above them in others. The suckers, for instance, a cartilaginous family, are the most imperfect of all vertebral animals; some of them want even the sense of sight; they seem mere worms, furnished with fins and gills, and were so classed by Linnæus; but though now ascertained to be in reality fishes, they must be regarded as the lowest link in the scale—as connecting the class with the class Vermes, just as the superior cartilaginous fishes may be regarded as connecting it with the class Reptilia.

[O] Some of the osseous fishes are also viviparous—the "viviparous blenny," for instance. The evidence from which the supposed affection of the higher fishes for their offspring has been inferred, is, I am afraid, of a somewhat equivocal character. The love of the sow for her litter hovers, at times, between that of the parent and that of the epicure; nor have we proof enough, in the present state of ichthyological knowledge, to conclude to which side the parental love of the fish inclines. The connubial affections of some of the higher families seem better established. Of a pair of gigantic rays (Cephaloptera giorna) taken in the Mediterranean, and described by Risso, the female was captured by some fishermen; and the male continued constantly about the boat, as if bewailing the fate of his companion, and was then found floating dead.—See Wilson's article Ichthyology, Encyc. Brit., seventh edition.

Between the osseous and the cartilaginous fishes there exist some very striking dissimilarities. The skull of the osseous fish is divided into a greater number of distinct bones, and possesses more movable parts, than the skulls of mammiferous animals: the skull of the cartilaginous fish, on the contrary, consists of but a single piece, without joint or suture. There is another marked distinction. The bony fish, if it approaches in form to that general type which we recognize amid all the varieties of the class as proper to fishes, and to which, in all their families, nature is continually inclining, will be found to have a tail branching out, as in the perch and herring, from the bone in which the vertebral column terminates; whereas the cartilaginous fish, if it also approach the general type, will be found to have a tail formed, as in the sturgeon and dog-fish, on both sides of the hinder portion of the spine, but developed much more largely on the under than on the upper side. In some instances, it is wanting on the upper side altogether. It may be as impossible to assign reasons for such relations as for those which exist between the digestive organs and the hoofs of the ruminant animals; but it is of importance that they should be noted.[P] It may be remarked, further, that the great bulk of fishes whose skeletons consist of cartilage have yet an ability of secreting the calcareous earth which composes bone, and that they are furnished with bony coverings, either partial or entire. Their bones lie outside. The thorn-back derives its name from the multitudinous hooks and spikes of bone that bristle over its body; the head, back, and operculum of the sturgeon are covered with bony plates; the thorns and prickles of the shark are composed of the same material. The framework within is a framework of mere animal matter; but it was no lack of the osseous ingredient that led to the arrangement—an arrangement which we can alone refer to the will of that all-potent Creator, who can transpose his materials at pleasure, without interfering with the perfection of his work. It is a curious enough circumstance, that some of the osseous fishes, as if entirely to reverse the condition of the cartilaginous ones, are partially covered with plates of cartilage. They are bone within, and cartilage without, just as others are bone without and cartilage within.

[P] Dr. Buckland, in his Bridgewater Treatise, assigns satisfactory reasons for this construction of tail in sharks and sturgeons. Of the fishes of these two orders, he states, "the former perform the office of scavengers, to clear the water of impurities, and have no teeth, but feed, by means of a soft, leather-like mouth, capable of protrusion and contraction, on putrid vegetables and animal substances at the bottom; and hence they have constantly to keep their bodies in an inclined position. The sharks employ their tail in another peculiar manner—to turn their body, in order to bring their mouth, which is placed downwards beneath the head, into contact with their prey. We find an important provision in every animal, to give a position of ease and activity to the head during the operation of feeding."—Bridgewater Treatise, p. 279, vol. i., first ed.

But how apply all this to the Geology of the Old Red Sandstone? Very directly. The ichthyolites of this ancient formation hold, as has been said, an intermediate place, unoccupied among present existences, between the two series, and in some respects resemble the osseous, and in some the cartilaginous tribes. The fact reminds one of Dr. Johnson's shrewd objection to the theory embraced by Soame Jenyns in his Free Inquiry, and which was the theory also of Pope and Bolingbroke. The metaphysician held, with the poet and his friend, that there exists a vast and finely graduated chain of being from Infinity to nonentity—from God to nothing; and that to strike out a single link would be to mar the perfection of the whole.[Q] The moralist demonstrated, on the contrary, that this chain, in the very nature of things, must be incomplete at both ends—that between that which does, and that which does not exist, there must be an infinite difference—that the chain, therefore, cannot lay hold on nothing. He showed, further, that between the greatest of finite existences and the adorable Infinite there must exist another illimitable void—that the boundless and the bounded are as widely separated in their natures and qualities as the existent and the non-existent—that the chain, in short, cannot lay hold on Deity. He asserted, however, that not only is it thus incomplete at both ends, but that we must regard it as well nigh as incomplete in many of its intermediate links as at its terminal ones; that it is already a broken chain, seeing that between its various classes of existence myriads of intermediate existences might be introduced, by graduating more minutely what must necessarily be capable of infinite gradation; and that, to base an infidel theory on the supposed completeness of what is demonstrably incomplete, and on the impossibility of a gap existing in what is already filled with gaps, is just to base one absurdity on another.[R] Now, we find the Geology of what may be termed the second age of vertebrated existence (for the Lower Old Red Sandstone was such) coming curiously in to confirm the reasonings of Johnson. It shows us the greater part of the fish of an entire creation thus insinuated between two of the links of our own.

[Q]

"See, through this air, this ocean, and this earth,
All matter quick, and bursting into birth;
Above, how high progressive life may go!
Around, how wide! how deep extend below!
Vast chain of being! which from God began—
Nature's ethereal, human angel, man,
Beast, bird, fish, insect—what no eye can see,
No glass can reach; from Infinite to thee—
From thee to nothing. On superior powers
Were we to press, inferior might on ours;
Or in the full creation leave a void,
Where, one step broken, the great scale's destroyed:
From Nature's chain, whatever link you strike,
Tenth, or ten thousandth, breaks the chain alike."

Essay on Man.

[R] The following are the well-stated reasonings of Dr. Johnson, a writer who never did injustice to an argument for want of words to express it in:—

"The scale of existence from Infinity to nothing cannot possibly have being. The highest being not infinite must be at an infinite distance from Infinity. Cheyne, who, with the desire inherent in mathematicians to reduce every thing to mathematical images, considers all existence as a cone, allows that the basis is at an infinite distance from the body, and in this distance between finite and infinite there will be room forever for an infinite series of indefinable existence.

"Between the lowest positive existence and nothing, whenever we suppose positive existence to cease, is another chasm infinitely deep, where there is room again for endless orders of subordinate nature, continued forever and ever, and yet infinitely superior to nonexistence.

"To these meditations humanity is unequal. But yet we may ask, not of our Maker, but of each other, since on the one side creation, whenever it stops, must stop infinitely below infinity, and on the other infinitely above nothing, what necessity there is that it should proceed so far either way—that being so high or so low should ever have existed. We may ask, but I believe no created wisdom can give an adequate answer.

"Nor is this all. In the scale, wherever it begins or ends, are infinite vacuities. At whatever distance we suppose the next order of beings to be above man, there is room for an intermediate order of beings between them; and if for one order, then for infinite orders, since every thing that admits of more or less, and consequently all the parts of that which admits them, may be infinitely divided; so that, as far as we can judge, there may be room in the vacuity between any two steps of the scale, or between any two points of the cone of being, for infinite exertion of infinite power."—Review of "A Free Inquiry."

It is now several years since I was first led to suspect that the condition of the ichthyolites of the Old Red Sandstone was intermediate. I have alluded to the comparative indestructibility of the osseous skeleton, and the extreme liability to decay characteristic of the cartilaginous one. Of a skeleton in part osseous and in part cartilaginous, we must, of course, expect, when it occurs in a fossil state, to find the indestructible portions only. And when, in every instance, we find the fossil skeletons of a formation complete in some of their parts, and incomplete in others—the entire portions invariably agreeing, and the wanting portions invariably agreeing also—it seems but natural to conclude that an original difference must have obtained, and that the existing parts, which we can at once recognize as bone, must have been united to parts now wanting, which were composed of cartilage. The naturalist never doubts that the shark's teeth, which he finds detached on the shore, or buried in some ancient formation, were united originally to cartilaginous jaws. Now, in breaking open all the ichthyolites of the Lower Old Red Sandstone, with the exception of those of the two families already described, we find that some of the parts are invariably wanting, however excellent the state of preservation maintained by the rest. I have seen every scale preserved and in its place—one set of both the larger and smaller bones occupying their original position—jaws thickly set with teeth still undetached from the head—the massy bones of the skull still unseparated—the larger shoulder-bone, on which the operculum rests, lying in its proper bed—the operculum itself entire—and all the external rays which support the fins, though frequently fine as hairs, spreading out distinct as the fibres in the wing of the dragon-fly, or the woody nerves in an oak-leaf. In no case, however, have I succeeded in finding a single joint of the vertebral column, or the trace of a single internal ray. No part of the internal skeleton survives, nor does its disappearance seem to have had any connection with the greater mass of putrescent matter which must have surrounded it, seeing that the external rays of the fins show quite as entire when turned over upon the body, as sometimes occurs, as when spread out from it in profile. Besides, in the ichthyolites of the chalk, no parts of the skeleton are better preserved than the internal parts—the vertebral joints, and the internal rays. The reader must have observed, in the cases of a museum of Natural History, preparations of fish of two several kinds—preparations of the skeleton, in which only the osseous parts are exhibited, and preparations of the external form, in which the whole body is shown in profile, with the fins spread to the full, and at least half the bones of the head covered by the skin but in which the vertebral column and internal rays are wanting. Now, in the fossils of the chalk, with those of the other later formations, down to the New Red Sandstone, we find that the skeleton style of preparation obtains; whereas, in at least three fourths of the ichthyolites of the Lower Old Red, we find only what we may term the external style. I had marked, besides, another circumstance in the ichthyolites, which seemed, like a nice point of circumstantial evidence, to give testimony in the same line. The tails of all the ichthyolites, whose vertebral columns and internal rays are wanting, are unequally lobed, like those of the dog-fish and sturgeon, (both cartilaginous fishes,) and the body runs on to nearly the termination of the surrounding rays. The one-sided condition of tail exists, says Cuvier, in no recent osseous fish known to naturalists, except in the bony pike—a sauroid fish of the warmer rivers of America. With deference, however, to so high an authority, it is questionable whether, the tail of the bony pike should not rather be described as a tail set on somewhat awry, than as a one-sided tail.

All these peculiarities I could but note as they turned up before me, and express, in pointing them out to a few friends, a sort of vague, because hopeless, desire, that good fortune might throw me in the way of the one man of all the world best qualified to explain the principle on which they occurred, and to decide whether fishes may be at once bony and cartilaginous. But that meeting was a contingency rather to be wished than hoped for—a circumstance within the bounds of the possible, but beyond those of the probable. Could the working-man of the north of Scotland have so much as dreamed that he was yet to enjoy an opportunity of comparing his observations with those of the naturalist of Neufchatel, and of having his inferences tested and confirmed?

The opportunity did occur. The working-man did meet with Agassiz; and many a query had he to put to him; and never, surely, was inquirer more courteously entreated, or his doubts more satisfactorily resolved. The reply to almost my first question solved the enigma of nearly ten years' standing. And finely characteristic was that reply of the frankness and candor of a great mind, that can afford to make it no secret, that, in its onward advances on knowledge, it may know to-day what it did not know yesterday, and that it is content to "gain by degrees upon the darkness." "Had you asked me the question a fortnight ago," said Agassiz, "I could not have replied to it. Since then, however, I have examined an ichthyolite of the Old Red Sandstone in which the vertebral joints are fortunately impressed on the stone, though the joints themselves have disappeared, and which, exactly resembling the vertebra? of the shark, must have been cartilaginous." In a subsequent conversation, the writer was gratified by finding most of his other facts and inferences authenticated and confirmed by those of the naturalist. I shall attempt introducing to the reader the peculiarities, general and specific, of the ichthyolites to which these facts and observations mainly referred, by describing such of the families as are most abundant in the formation, and the points in which they either resemble or differ from the existing fish of our seas.

PLATE IV.

Of these ancient families, the Osteolepis, or bony-scale, (see [Plate IV.], fig. 1,) may be regarded as illustrative of the general type. It was one of the first discovered of the Caithness fishes, and received its name in the days of Cuvier, from the osseous character of its scales, ere it was ascertained that it had numerous contemporaries, and that to all and each of these the same description applied. The scales of the fishes of the Lower Old Red Sandstone, like the plates and detached prickles of the purely cartilaginous fishes, were composed of a bony, not of a horny, substance, and were all coated externally with enamel. The circumstance is one of interest.

Agassiz, in his system of classification, has divided fishes into four orders, according to the form of their scales; and his principle of division, though apparently arbitrary and trivial, is yet found to separate the class into great natural families, distinguished from one another by other and very striking peculiarities. One kind of scale, for instance, the placoid or broad-plated scale, is found to characterize all the cartilaginous fishes of Cuvier except the sturgeon;—it is the characteristic of an otherwise well-marked series, whose families are furnished with skeletons composed of mere animal matter, and whose gills open to the water by spiracles. The fish of another order are covered by ctenoid or comb-shaped scales, the posterior margin of each scale being toothed somewhat like the edge of a saw or comb; and the order, thus distinguished, is found wonderfully to agree with an order formed previously on another principle of classification, the Acanthopterygii, or thorny-finned order of Cuvier, excluding only the smooth-scaled families of this previously formed division, and including, in addition to it, the flat fish. A third order, the Cycloidean, is marked by simple marginated scales, like those of the cod, haddock, whiting, herring, salmon, &c.; and this order is found to embrace chiefly the Malacopterygii, or soft-finned order of Cuvier—an order to which all these well-known fish, with an immense multitude of others, belong. Thus the results of the principle of classification adopted by Agassiz wonderfully agree with the results of the less simple principles adopted by Cuvier and the other masters in this department of Natural History. Now, it is peculiar to yet a fourth order, the Ganoidean, or shining-scaled order, that by much the greater number of the genera which it comprises exist only in the fossil state. At least five sixths of the whole were ascertained to be extinct several years ago, at a time when the knowledge of fossil Ichthyology was much more limited than at present: the proportions are now found to be immensely greater on the side of the dead. And this order seems to have included all the semi-osseous, semi-cartilaginous ichthyolites of the Lower Old Red Sandstone: the enamelled scale is the characteristic, according to Agassiz's principle of classification, of the existences that filled the gap so often alluded to as existing in the present creation. All their scales glitter with enamel: they bore to this order the relation that the cartilaginous fish bear to the Placoidean order, the thorny-finned fish to the Ctenoidean order, and the soft-finned fish to the Cycloidean order. It also included, with the semi-cartilaginous, the sauroid fish—those master existences and tyrants of the earlier vertebrata; and both classes find their representatives among the comparatively few ganoid fishes of the present creation; the one in the sturgeon family, which of all existing families approaches nearest in other respects to the extinct semi-cartilaginous fishes; the other in the sauroid genus Lepidosteus, to which the bony pike belongs. The head, back, and sides of the sturgeon are defended, as has been already remarked, by longitudinal rows of hard osseous bosses—the bony pike is armed with enamelled osseous scales, of a stony hardness. It seems a somewhat curious circumstance, that fishes so unlike each other in their internal framework should thus resemble one another in their bony coverings, and in some slight degree in their structure of tail. One of the characteristics of sauroid fishes is the extreme compactness and hardness of their skeleton.[S]

[S] "The sauroid or lizard-like fishes," says Dr. Buckland, "combine in the structure, both of the bones and some of the soft parts, characters which are common to the class of reptiles. The bones of the skull are united by closer sutures than those of common fishes. The vertebræ articulate with the spinous processes of sutures, like the vertebræ of saurians; the ribs also articulate with the extremities of the spinous process. The caudal vertebræ have distinct chevron bones, and the general condition of the skeleton is stronger and more solid than in other fishes: the air bladder also is bifid and cellular, approaching to the character of lungs; and in the throat there is a glottis, as in sirens and salamanders, and many saurians."—Note to Bridgewater Treatise, p. 274, first edit.

It requires skill such as that possessed by Agassiz, to determine that the uncouth Coccosteus, or the equally uncouth Pterichthys, of the Old Red Sandstone, with their long articulated tails and tortoise-like plates, were bona fide fishes; but there is no possibility of mistaking the Osteolepis: it is obvious to the least practised eye that it must have been a fish, and a handsome one. Even a cursory examination, however, shows very striking peculiarities, which are found, on further examination, to characterize not this family alone, but at least one half the contemporary families besides. We are accustomed to see vertebrated animals with the bone uncovered in one part only,—that part the teeth,—and with the rest of the skeleton wrapped up in flesh and skin. Among the reptiles, we find a few exceptions; but a creature with a skull as naked as its teeth,—the bone being merely covered, as in these, by a hard, shining enamel,—and with toes also of bare enamelled bone, would be deemed an anomaly in creation. And yet such was the condition of the Osteolepis, and many of its contemporaries. The enamelled teeth were placed in jaws which presented outside a surface as naked and as finely enamelled as their own. (See [Plate IV.], fig. 5.) The entire head was covered with enamelled osseous plates, furnished inside like other bones, as shown by their cellular construction, with their nourishing blood vessels, and perhaps their oil, and which rested apparently on the cartilaginous box, which must have enclosed the brain, and connected it with the vertebral column. I cannot better illustrate the peculiar condition of the fins of this ichthyolite than by the webbed foot of a water-fowl. The web or membrane in all the aquatic birds with which we are acquainted not only connects, but also covers the toes. The web or membrane in the fins of existing fishes accomplishes a similar purpose; it both connects and covers the supporting bones or rays. Imagine, however, a webbed foot in which the toes—connected, but not covered—present, as in skeletons, an upper and under surface of naked bone; and a very correct idea may be formed, from such a foot, of the condition of fin which obtained among at least one half the ichthyolites of the Lower Old Red Sandstone. The supporting bones or rays seem to have been connected laterally by the membrane; but on both sides they presented bony and finely enamelled surfaces. (See [Plate IV.], fig. 6.) In this singular class of fish, all was bone without, and all was cartilage within; and the bone in every instance, whether in the form of jaws or of plates, of scales or of rays, presented an external surface of enamel.

The fins are quite a study. I have alluded to the connecting membrane. In existing fish this membrane is the principal agent in propelling the creature; it strikes against the water, as the membrane of the bat's wing strikes against the air; and the internal skeleton serves but to support and stiffen it for this purpose. But in the fin of the Osteolepis, as in those of many of its contemporaries, we find the condition reversed. The rays were so numerous, and lay so thickly, side by side, like feathers in the wing of a bird, that they presented to the water a surface of bone, and the continuous membrane only served to support and bind them together. In the fins of existing fish we find a sort of bat-wing construction; in those of the Osteolepis a sort of bird-wing construction. The rays, to give flexibility to the organ which they compose, were all jointed, as in the soft-finned fish—as in the herring, salmon, and cod, for example; and we find in all the fins the anterior ray rising from the body in the form of an angular scale: it is a strong, bony scale in one of its joints, and a bony ray in the rest. The characteristic is a curious one.

It is again necessary, in pursuing our description, to refer for illustration to the purely cartilaginous fishes. In at least all the higher orders of these, furnished with movable jaws, such as the sturgeon, the ray, and the shark, the mouth is placed far below the snout. The dog-fish and thorn-back are familiar instances. Further, the mouth in bony fishes is movable on both the upper and under side, like the beak of the parrot; in the higher cartilaginous fishes it is movable, as in quadrupeds, on the under side only. In all their orders, too, except in that of the sturgeon, the gills open to the water by detached spiracles, or breathing-holes; but in the sturgeon, as in the osseous fishes, there is a continuous linear opening, shielded by an operculum, or gill-cover. In the Osteolepis the mouth opened below the snout, but not so far below it as in the purely cartilaginous fishes—not farther below it than in many of the osseous ones—than in the genus Aspro, for instance, or than in the genus Polynemus, or in even the haddock or cod. It was thickly furnished with slender and sharply-pointed teeth. I have hitherto been unable fully to determine whether, like the mouths of the osseous fishes, it was movable on both sides; though, from the perfect form of what seems to be the intermaxillary bone, I cannot avoid thinking it was. The gills opened, as in the osseous fishes, in continuous lines, and were covered by large bony opercules—that on the enamelled side somewhat resemble round japanned shields.

But while the head of the Osteolepis, with its appendages, thus resembled, in some points, the heads of the bony fishes, the tail, like those of most of its contemporaries, differed in no respect from the tails of cartilaginous ones, such as the sturgeon. The vertebral column seems to have run on to well nigh the extremity of the caudal fin, which we find developed chiefly on the under side. The tail was a one-sided tail. Take into account with these peculiarities—peculiarities such as the naked skull, jaws, and operculum, the naked and thickly-set rays, and the unequally lobed condition of tail—a body covered with scales, that glitter like sheets of mica, and assume, according to their position, the parallelogramical, rhomboidal, angular, or polygonal form—a lateral line raised, not depressed—a raised bar on the inner or bony side of the scales, which, like the doubled-up end of a tile, seems to have served the purpose of fastening them in their places—a general clustering of alternate fins towards the tail—and the tout ensemble must surely impart to the reader the idea of a very singular little fish. The ventral fins front the space which occurs between the two dorsals, and the anal fin the space which intervenes between the posterior dorsal fin and the tail. The length of the Osteolepis, in my larger specimens, somewhat exceeds a foot; in the smaller, it falls short of six inches. There exist at least three species of this ichthyolite, distinguished chiefly, in two of the instances, by the smaller and larger size of their scales, compared with the bulk of their bodies, and by punctulated markings on the enamel in the case of the third. This last, however, is no specific difference, but common to the entire genus, and to several other genera besides. The names are, Osteolepis macrolepidotus, O. microlepidotus, and O. arenatus.[T]

[T] To these there have since been added Osteolepis major, O. intermedius, and O. nanus; the two latter, however, Agassiz regards as doubtful.

PLATE V.

Next to the Osteolepis we may place the Dipterus, or double-wing, of the Lower Old Red Sandstone, an ichthyolite first introduced to the knowledge of geologists by Mr. Murchison, who, with his friend, Mr. Sedgwick, figured and described it in a masterly paper on the older sedimentary formations of the north of Scotland, which appeared in the Transactions of the Geological Society of London for 1828. The name, derived from its two dorsals, would suit equally well, like that of the Osteolepis, many of its more recently discovered contemporaries. From the latter ichthyolite it differed chiefly in the position of its fins, which were opposite, not alternate; the double dorsals exactly fronting the anal and ventral fins. (See [Plate V.], fig. 1.) The Diplopterus, a nearly resembling ichthyolite of the same formation, also owes its name to the order and arrangement of its fins, which, like those of the Dipterus, were placed fronting each other, and in pairs. But the head, in proportion to the body, was in greater size than in either the Dipterus or Osteolepis; and the mouth, as indicated by the creature's length of jaw, must have been of much greater width. In their more striking characteristics, however, the three genera seem to have nearly agreed. In all alike, scales of bone glisten with enamel; their jaws, enamel without and bone within, bristle thick with sharp-pointed teeth; closely-jointed plates, burnished like ancient helmets, cover their heads, and seem to have formed a kind of outer table to skulls externally of bone and internally of cartilage; their gill-covers consist each of a single piece, like the gill-cover of the sturgeon; their tails were formed chiefly on the lower side of their bodies; and the rays of their fins, enamelled like their plates and their scales, stand up over the connecting membrane, like the steel or brass in that peculiar armor of the middle ages, whose multitudinous pieces of metal were fastened together on a groundwork of cloth or of leather. All their scales, plates, and rays present a similar style of ornament. The shining and polished enamel is mottled with thickly-set punctures, or, rather, punctulated markings; so that a scale or plate, when viewed through a microscope, reminds one of the cover of a saddle. Some of the ganoid scales of Burdie House present surfaces similarly punctulated.[U]

[U] There exists, according to Agassiz, only a single species of Dipterus—D. macrelepidotus; whereas four species of Diplopterus have been enumerated—D. affinis, D. borealis, D. macrocephalus, and D. Agassizii. The existence of the last named, however, as a distinct species, is regarded as problematical by the distinguished naturalist whose name has been affixed to it.

The Glyptolepis, or carved scale, may be regarded as the representative of a family of the Lower Old Red Sandstone, which, differing very materially from the genera described, had yet many traits in common with them, such as the bare, bony skull, the bony scales, the naked rays, and the unequally sided condition of tail. The fins, which were of considerable length in proportion to their breadth of base, and present in some of the specimens a pendulous-like appearance, cluster thick together towards the creature's lower extremities, leaving the upper portion bare. There are two dorsals placed as in the Dipterus and Diplopterus—the anterior directly opposite the ventral fin, the posterior directly opposite the anal. The tail is long and spreading;—the rays, long and numerously articulated, are comparatively stout at their base, and slender as hairs where they terminate. The shoulder-bones are of huge dimensions, the teeth extremely minute. But the most characteristic parts of the creature are the scales. They are of great size, compared with the size of the animal. An individual not more than half a foot in length, the specimen figured, (see [Plate V.], fig. 2,) exhibits scales fully three eighth parts of an inch in diameter. In another more broken specimen there are scales a full inch across, and yet the length of the ichthyolite to which they belonged seems not to have much exceeded a foot and a half. Each scale consists of a double plate, an inner and an outer. The structure of the inner is not peculiar to the family or the formation: it is formed of a number of minute concentric circles, crossed by still minuter radiating lines—the one described, and the other proceeding from a common centre. (See [Plate V.], fig. 5.) All scales that receive their accessions of growth equally at their edges exhibit, internally, a corresponding character. The outer plate presents an appearance less common. It seems relieved into ridges that drop adown it like sculptured threads, some of them entire, some broken, some straight, some slightly waved, (see [Plate V.], fig. 3;) and hence the name of the ichthyolite. The plates of the head were ornamented in a similar style, but their threads are so broken as to present the appearance of dotted lines, the dots all standing out in bold relief. My collection contains three varieties of this family; one of them disinterred from out the Cromarty beds about seven years ago, and the others only a little later, though partly from the inadequacy of a written description, through which I was led to confound the Osteolepis with the Diplopterus, and to regard the Glyptolepis as the Osteolepis, I was not aware until lately that the discovery was really such; and under the latter name I described the creature in the Witness newspaper several weeks ere it had received the name which it now bears. It was first introduced to the notice of Agassiz, in Autumn last, by Lady Cumming of Altyre. The species, however, was a different one from any yet found at Cromarty.[V]

[V] There are three species of Glyptolepis—G. elegans, G. Leptopterus, and G. microlepidotus.

The Cheirolepis, or scaly pectoral, forms the representative of yet another family of the Lower Old Red Sandstone, and one which any eye, however unpractised, could at once distinguish from the families just described. Professor Traill of the University of Edinburgh, a gentleman whose researches in Natural History have materially extended the boundaries of knowledge, and whose frankness in communicating information is only equalled by his facility in acquiring it, was the first discoverer of this family, one variety of which, the Cheirolepis Traillii, bears his name. The figured specimen ([Plate VI.], fig. 1) Agassiz has pronounced a new species, the discovery of the writer. In all the remains of this curious fish which I have hitherto seen, the union of the osseous with the cartilaginous, in the general framework of the creature, is strikingly apparent. The external skull, the great shoulder-bone, and the rays of the fins, are all unequivocally osseous; the occipital and shoulder-bones, in particular, seem of great strength and massiveness, and are invariably preserved, however imperfect the specimen in other respects; whereas, even in specimens the most complete, and which exhibit every scale and every ray, however minute, and show unchanged the entire outline of the animal, not a fragment of the internal skeleton appears. The Cheirolepis seems to have varied from fourteen to four inches in length. When seen in profile, the under line, as in the figured variety, seems thickly covered with fins, and the upper line well nigh naked. The large pectorals almost encroach on the ventral fins, and the ventrals on the anal fin; whereas the back, for two thirds the entire length of the creature, presents a bare rectilinear ridge, and the single dorsal, which rises but a little way over the tail, immediately opposite the posterior portion of the anal fin, is comparatively of small size. The tail, which, in the general condition of being developed chiefly on the lower side, resembles the tails of all the creature's contemporaries, is elegantly lobed. The scales, in proportion to the bulk of the body which they cover, are not more than one twentieth the size of those of the Osteolepis. They are richly enamelled, and range diagonally from the shoulder to the belly in waving lines; and so fretted is each individual scale by longitudinal grooves and ridges, that, on first bringing it under the glass, it seems a little bunch of glittering thorns, though, when more minutely examined, it is found to be present somewhat the appearance of the outer side of the deep-sea cockle, with its strongly marked ribs and channels, the point in which the posterior point terminates representing the hinge. (See [Plate VI.], fig. 2.) The bones of the head, enamelled like the scales, are carved into jagged inequalities, somewhat resembling those on the skin of the shark, but more irregular. The sculpturings seem intended evidently for effect. To produce harmony of appearance between the scaly coat and the enamelled occipital plates of bone, the surfaces of the latter are relieved, where they border on the shoulders, into what seem scales, just as the dead walls of a building are sometimes, for the sake of uniformity, wrought into blind windows. The enamelled rays of the fins are finished, if I may so speak, after the same style. They lie thick upon one another as the fibres of a quill, and like these, too, they are imbricated on the sides, so that the edge of each seems jagged into a row of prickles. (See [Plate VI.], fig. 3.) The jaws of the Cheirolepis were armed with thickly-set sharp teeth, like those of its contemporaries, the Osteolepis and Diplopterus.[W]

[W] There have been five species of Cheirolepis enumerated—C. Cummingiæ, C. splendens, C. Traillii, C. unilateralis and C. Uragus. The Cheirolepis splendens and C. unilateralis Agassiz regards as doubtful.

PLATE VI.

[CHAPTER V.]

The Classifying Principle, and its Uses.—Three groups of Ichthyolites among the Organisms of the Lower Old Red Sandstone.—Peculiarities of the Third Group.—Its Varieties.—Description of the Cheiracanthus.—Of two unnamed Fossils of the same Order.—Microscopic Beauty of these Ancient Fish.—Various Styles of Ornament which obtain among them.—The Molluscs of the Formation.—Remarkable chiefly for the Union of Modern with Ancient Forms which they exhibit.—Its Vegetables.—Importance and Interest of the Record which it furnishes.

There rests in the neighborhood of Cromarty, on the upper stratum of one of the richest ichthyolite beds I have yet seen, a huge water-rolled boulder of granitic gneiss, which must have been a traveller, in some of the later periods of geological change, from a mountain range in the interior highlands of Ross-shire, more than sixty miles away. It is an uncouth looking mass, several tons in weight, with a flat upper surface, like that of a table; and as a table, when engaged in collecting my specimens, I have often found occasion to employ it. I have covered it over, times without number, with fragments of fossil fish—with plates, and scales, and jaws, and fins, and, when the search proved successful, with entire ichthyolites. Why did I always arrange them, almost without thinking of the matter, into three groups? Why, even when the mind was otherwise employed, did the fragments of the Coccosteus and Pterichthys come to occupy one corner of the stone, and those of the various fish just described another corner, and the equally well-marked remains of a yet different division a third corner? The process seemed almost mechanical, so little did it employ the attention, and so invariable were the results. The fossils of the surrounding bed always found their places on the huge stone in three groups, and at times there was yet a fourth group added—a group whose organisms belonged not to the animal, but the vegetable kingdom. What led to the arrangement, or in what did it originate? In a principle inherent in the human mind—that principle of classification which we find pervading all science—which gives to each of the many cells of recollection its appropriate facts—and without which all knowledge would exist as a disorderly and shapeless mass, too huge for the memory to grasp, and too heterogeneous for the understanding to employ. I have described but two of the groups, and must now say a very little about the principle on which, justly or otherwise, I used to separate the third, and on the distinctive differences which rendered the separation so easy.

The recent bony fishes are divided, according to the Cuvierian system of classification, into two great orders, the soft-finned and the thorny-finned order—the Malacopterygii and the Acanthopterygii. In the former the rays of the fins are thin, flexible, articulated, branched: each ray somewhat resembles a jointed bamboo; with this difference, however, that what seems a single ray at bottom, branches out into three or four rays a-top. In the latter, (the thorny-finned order,)—especially in their anterior dorsal, and perhaps anal fins,—the rays are stiff continuous spikes of bone, and each stands detached as a spear, without joint or branch. The perch may be instanced as a familiar illustration of this order—the gold-fish of the other. Now, between the fins of two sets—shall I venture to say orders?—of the ichthyolites of the Lower Old Red Sandstone, an equally striking difference obtains. The fin of the Osteolepis, with its surface of enamelled and minutely jointed bones, I have already described as a sort of bird-wing fin. The naked rays, with their flattened surfaces, lay thick together as feathers in the wing of a bird—so thick as to conceal the connecting membrane; and fins of similar construction characterized the families of the Dipterus, Diplopterus, Glyptolepis, Cheirolepis, Holoptychius, and, I doubt not, many other families of the same period, which await the researches of future discoverers. But the fins of another set of ichthyolites, their contemporaries, may be described as bat-wing fins: they presented to the water a broad expanse of membrane; and the solitary ray which survives in each was not a jointed, but a continuous spear-like ray. The fins of this set, or order, are thorny-fins, like those of the Acanthopterygii; the anterior edge of each, with the exception of, perhaps, the caudal fin, which differs in construction from the others, is composed of a strong, bony spike. Such, with some tacit reference, perhaps, to the similar Cuvierian principle of classification, were the distinctive differences, on the strength of which I used to arrange two of my groups of fossils on the granitic boulder; and the influence of the same principle, almost instinctively exerted,—for, in writing the previous pages, I scarce thought of its existence,—has, I find, given to each group its own chapter.

Of the membranous-finned and thorny-rayed order of ichthyolites, the Cheiracanthus, or thorny-hand, (i. e. pectoral,) may be regarded as an adequate representative. (See [Plate VII.], fig. 1.) The Cheiracanthus must have been an eminently handsome little fish—slim, tapering, and described in all its outlines, whether of the body or the fins, by gracefully waved lines. It is, however, a rare matter to find it presenting its original profile in the stone;—none of the other ichthyolites are so frequently distorted as the Cheiracanthus. It seems to have been more a cartilaginous and less an osseous fish than most of its contemporaries. However perfect the specimen, no part of the internal skeleton is ever found, not even when scales as minute as the point of a pin are preserved, and every spine stands up in its original place. And hence, perhaps, a greater degree of flexibility, and consequent distortion. The body was covered with small angular scales, brightly enamelled, and delicately fretted into parallel ridges, that run longitudinally along the upper half of the scale, and leave the posterior portion of it a smooth, glittering surface. (See [Plate VII.], fig. 2.) They diminish in size towards the head, which, from the faint stain left on the stone, seems to have been composed of cartilage exclusively, and either covered with skin, or with scales of extreme minuteness. The lower edge of the operculum bears a tagged fringe, like that of a curtain. The tail, a fin of considerable power, had the unequal sided character common to the formation; and the slender and numerous rays on both sides are separated by so many articulations as to present the appearance of parallelogramical scales. The other fins are comparatively of small size. There is a single dorsal placed about two thirds the entire length of the creature adown the back; and exactly opposite its posterior edge is the anterior edge of the anal fin. The ventral fins are placed high upon the belly, somewhat like those of the perch; the pectorals only a little higher. But it is rather in the construction of the fins, than their position, that the peculiarities of the Cheiracanthus are most marked. The anterior edge of each, as in the pectorals of the existing genera Cestracion and Chimæra, is formed of a strong, large spine. In the Chimæra borealis, a cartilaginous fish of the Northern Ocean, the spine seems placed in front of the weaker rays, just, if I may be allowed the comparison, as, in a line of mountaineers engaged in crossing a swollen torrent, the strongest man in the party is placed on the upper side of the line, to break off the force of the current from the rest. In the Cheiracanthus, however, each fin seems to consist of but a single spine, with an angular membrane fixed to it by one of its sides, and attached to the creature's body on the other. Its fins are masts and sails—the spine representing the mast, and the membrane the sail; and it is a curious characteristic of the order, that the membrane, like the body, of the ichthyolite, is thickly covered with minute scales. The mouth seems to have opened a very little under the snout, as in the haddock; and there are no indications of its having been furnished with teeth.[X]

[X] There have been three species of Cheiracanthus determined—C. microlepidotus, C. minor, and C. Murchisoni.

PLATE VII.

An ichthyolite first discovered by the writer about three years ago, and introduced by him to the notice of Agassiz during his recent visit to Edinburgh, but still unfurnished with a name,[Y] is a still more striking representative of this order than even the Cheiracanthus. It must have been proportionally thick and short, like some of the tropical fishes, though rather handsome than otherwise. (See [Plate VIII.], fig. 1.) The scales, minute, but considerably larger than those of the Cheiracanthus, are of a rhomboidal form, and so regularly striated—the striæ converging to a point at the posterior termination of each scale—that, when examined with a glass, the body appears as if covered with scallops. (See Plate VIII., fig. 3.) It seems a piece of exquisite shell-work, such as we sometimes see on the walls of a grotto. There are two dorsals—the posterior, immediately over the tail, and directly opposite the anal fin; the anterior, somewhat higher up than the ventrals; and all the fins are of great size. The anterior edge of each is formed of a strong spine, round as the handle of a halbert, and diminishing gradually and symmetrically to a sharp point. Though formed externally of solid bone, it seems to have been composed internally of cartilage, like the bones of some of the osseous fishes—those of the halibut, for instance; and the place of the cartilage is generally occupied in the stone by carbonate of lime. The membrane which formed the body of the fin was covered, like that of the Cheiracanthus, with minute scales, of the same scallop-like pattern with the rest, but of not more than one sixth the size of those which cover the creature's sides and back. Imagine two lug-sails stiffly extended between the deck of a brigantine and her two masts, the latter raking as far aft as to form an angle of sixty degrees with the horizon, and some idea may be formed of the dorsals of this singular fish. They were lug-sails, formed not to be acted upon by the air, but to act upon the water. None of my specimens show the head; but, judging from analogies furnished by the other families of the group, I entertain little doubt that it will be found to be covered, not by bony plates, but by minute scales, diminishing, as they approach the snout, into mere points. In none of the specimens does any part of the internal skeleton survive.

[Y] Now determined to be a species of Diplacanthus—D. longispinus.

PLATE VIII.

My collection contains the remains of yet another fish of this group, which was unfurnished with a name only a few months ago, but which I first discovered about five years since. (See [Plate VIII.], fig. 2.) It is now designated the Diplacanthus; and, though the smallest ichthyolite of the formation yet known, it is by no means the least curious. The length from head to tail, in some of my specimens, does not exceed three inches; the largest fall a little short of five. The scales, which are of such extreme minuteness that their peculiarities can be detected by only a powerful glass, resemble those of the Cheiracanthus; but the ridges are more waved, and seem, instead of running in nearly parallel lines, to converge towards the apex. There are two dorsals, the one rising immediately from the shoulder, a little below the nape, the other directly opposite the anal fin. The ventrals are placed near the middle of the belly. There is a curious mechanism of shoulder-bone involved with a lateral spine and with the pectorals. The creature, unlike the Cheiracanthus, seems to have been furnished with jaws of bone: there are fragments of bone upon the head, tubercled apparently on the outer surface; and minute cylinders of carbonate of lime running along all the larger bones, where we find them accidentally laid open, show that they were formed on internal bases of cartilage. But the best marked characteristic of the creature is furnished by the spines of its fins, which are of singular beauty. Each spine resembles a bundle of rods, or, rather, like a Gothic column, the sculptured semblance of a bundle of rods, which finely diminish towards a point, sharp and tapering as that of a rush. (See [Plate VIII.], fig. 4.)[Z] The rest of the fin presents the appearance of a mere scaly membrane, and no part of the internal skeleton appears. Perhaps this last circumstance, common to all the ichthyolites of the formation, if we except the families of the Coccosteus and Pterichthys, may throw some light on the apparently membranous condition of fin peculiar to the families of this order. What appears in the fossil a mere scaly membrane attached to a single spine of bone, may have had in the living animal a cartilaginous framework, like the fins of the dog-fish and thorn-back, that are amply furnished with rays of cartilage—though, of course, all such rays must have disappeared in the stone, like the rest of the internal skeleton. Unquestionably, the caudal fin of the two last described fossils must have been strengthened by some such internal framework; for, as they differ from the other fins, in being unprovided with osseous spines, they would have formed, without an internal skeleton, mere pendulous attachments, altogether unfitted to serve the purposes of instruments of motion. There may be found in the bony spines of all this order direct proof that, had there been an internal skeleton of bone, it would have survived. The spines run deep into the body, as a ship's masts run deep into her hulk; and we can see them standing up among the scales to their termination, in such bold relief, that, from a sort of pictorial illusion, they seem as if fixed to the creature's sides, and foreshortened, instead of rising in profile from its back or belly. (See [Plate VIII.], fig. 1.) The observer will of course remember, that, in the living animal, the view of the spine must have terminated with the line of the profile, just as the view of a vessel's mast terminates with the deck, though the mast itself penetrates to the interior keel. Now, it must be deemed equally obvious, that, had the vertebral column been of bone, not of cartilage, instead of exhibiting no trace, even the faintest, of having ever existed, it would have stood out in as high relief as the internal buts or stocks of the spines. And such are the general characteristics of a few of the ichthyolites of this lower formation of the Old Red Sandstone—a few of the more striking forms, sculptured, if I may so speak, on the middle compartment of the Caithness pyramid. It would be easy rendering the list more complete at even the present stage, when the field is still so new that almost every laborer in it can exhibit genera and species unknown to his brother laborers. The remains of a species of Holoptychius have been discovered low in the formation, at Orkney, by Dr. Traill; similar remains have been found in it at Gamrie. In its upper beds the specimens seem so different from those in the lower, that, in extensive collections made from the inferior strata of one locality, Agassiz has been unable to identify a single specimen with the specimens of collections made from the superior strata of another, though the genera are the same. Meanwhile there are heads and hands at work on the subject; Geology has become a Briareus; and I have little doubt that, in five years hence, this third portion of the Old Red Sandstone will be found to contain as many distinct varieties of fossil fish as the whole geological scale was known to contain fifteen years ago.[AA]

[Z] Agassiz reckons four species of Diplacanthus—D. crassispinus, D. longispinus, D. striatulus, and D. striatus.

[AA] This prediction has been already more than accomplished. At the death of Cuvier, in 1832, there were but ninety-two species of fossil fish known to the geologist; Agassiz now enumerates one hundred and five species that belong to the Old Red Sandstone alone; and if we include doubtful species, on which he has not authoritatively decided—some of which, however, were included in the list of Cuvier—one hundred and fifty-one.

There is something very admirable in the consistency of style which obtains among the ichthyolites of this formation. In no single fish of either group do we find two styles of ornament—in scarce any two fishes do we find exactly the same style. I pass fine buildings almost every day. In some there is a discordant jumbling—an Egyptian Sphinx, for instance, placed over a Doric portico; in all there prevails a vast amount of timid imitation. The one repeats the other, either in general outline or in the subordinate parts. But the case is otherwise among the ichthyolites of the Old Red Sandstone; nor does it lessen the wonder, that their nicer ornaments should yield their beauty only to the microscope. There is unity of character in every scale, plate, and fin—unity such as all men of taste have learned to admire in those three Grecian orders from which the ingenuity of Rome was content to borrow, when it professed to invent—in the masculine Doric, the chaste and graceful Ionic, the exquisitely elegant Corinthian; and yet the unassisted eye fails to discover the finer evidences of this unity: it would seem as if the adorable Architect had wrought it out in secret with reference to the Divine idea alone. The artist who sculptured the cherry-stone consigned it to a cabinet, and placed a microscope beside it; the microscopic beauty of these ancient fish was consigned to the twilight depths of a primeval ocean. There is a feeling which at times grows upon the painter and the statuary, as if the perception and love of the beautiful had been sublimed into a kind of moral sense. Art comes to be pursued for its own sake; the exquisite conception in the mind, or the elegant and elaborate model, becomes all in all to the worker, and the dread of criticism or the appetite of praise almost nothing. And thus, through the influence of a power somewhat akin to conscience, but whose province is not the just and the good, but the fair, the refined, the exquisite, have works prosecuted in solitude, and never intended for the world, been found fraught with loveliness. Sir Thomas Lawrence, when finishing, with the most consummate care, a picture intended for a semi-barbarous, foreign court, was asked why he took so much pains with a piece destined, perhaps, never to come under the eye of a connoisseur. "I cannot help it," he replied; "I do the best I can, unable, through a tyrant feeling, that will not brook offence, to do any thing less." It would be perhaps over bold to attribute any such overmastering feeling to the Creator; yet certain it is, that among his creatures well nigh all approximations towards perfection, in the province in which it expatiates, owe their origin to it, and that Deity in all his works is his own rule.

The Osteolepis was cased, I have said, from head to tail, in complete armor. The head had its plaited mail, the body its scaly mail, the fins their mail of parallel and jointed bars; the entire suit glittered with enamel; and every plate, bar, and scale was dotted with microscopic points. Every ray had its double or treble punctulated row, every scale or plate its punctulated group; the markings lie as thickly in proportion to the fields they cover, as the circular perforations in a lace veil; and the effect, viewed through the glass, is one of lightness and beauty. In the Cheirolepis an entirely different style obtains. The enamelled scales and plates glitter with minute ridges, that show like thorns in a December morning varnished with ice. Every ray of the fins presents its serrated edge, every occipital plate and bone its sculptured prominences, every scale its bunch of prickle-like ridges. A more rustic style characterized the Glyptolepis. The enamel of the scales and plates is less bright; the sculpturings are executed on a larger scale, and more rudely finished. The relieved ridges, waved enough to give them a pendulous appearance, drop adown the head and body. The rays of the fins, of great length, present also a pendulous appearance. The bones and scales seem disproportionately large. There is a general rudeness in the finish of the creature, if I may so speak, that reminds one of the tattooings of a savage, or the corresponding style of art in which he ornaments the handle of his stone-hatchet or his war-club. In the Cheiracanthus, on the contrary, there is much of a minute and cabinet-like elegance. The silvery smoothness of the fins, dotted with scarcely visible scales, harmonized with a similar appearance of head; a style of sculpture resembling the parallel etchings of the line-engraver fretted the scales; the fins were small, and the contour elegant. I have already described the appearance of the unnamed fossils—the seeming shell-work that covered the sides of the one—its mast-like spines and sail-like fins; and the Gothic-like peculiarities that characterized the other—its rodded, obelisk-like spines, and the external framework of bone that stretched along its pectorals.

Till very lately, it was held that the Old Red Sandstone of Scotland contained no mollusca. It seemed difficult, however, to imagine a sea abounding in fish, and yet devoid of shells. In all my explorations, therefore, I had an eye to the discovery of the latter, and on two several occasions I disinterred what I supposed might have formed portions of a cardium or terebratula. On applying the glass, however, the punctulated character of the surface showed that the supposed shells were but parts of the concave helmet-like plate that covered the snout of the Osteolepis. In the ichthyolite beds of Cromarty and Ross, of Moray, Banff, Perth, Forfar, Fife, and Berwickshire, not a single shell has yet been found; but there have been discovered of late, in the upper beds of the Lower Old Red Sandstone in Orkney, the remains of a small, delicate bivalve, not yet described or figured, but which very much resembles a Venus. (See [Plate V.], fig. 7.) In the Tilestones of England, so carefully described by Mr. Murchison in his Silurian System, shells are very abundant; and the fact may now be regarded as established, that the Tilestones of England belong to a deposit contemporaneous with the ichthyolite beds of Caithness and Cromarty. They occupy the same place low in the base of the Old Red; and there is at least one ichthyolite common to both,[AB] and which does not occur in the superior strata of the system in either country—the Dipterus macrolepidotus. The evidence that the fish and shells lived in the same period, and represent, therefore, the same formation, may be summed up in a single sentence. We learn from the Geology of Caithness that this species of Dipterus was unquestionably contemporary with all the other ichthyolites described;—we learn from the Geology of Herefordshire that the shells were as unquestionably contemporary with it.[AC] These—the shells—are of a singularly mixed character, regarded as a group, uniting, says Mr. Murchison, forms at one time deemed characteristic of the more modern formations,—of the latter secondary, and even tertiary periods,—with forms the most ancient, and which characterize the molluscous remains of the transition rocks. Turbinated shells and bivalves of well nigh the recent type may be found lying side by side with chambered Orthoceratites and Terebratula.[AD]

[AB] Silurian System, part ii. p. 599.

[AC] In Russia, too, as shown by the recent discoveries of Murchison, the Old Red fishes of Caithness, and the Old Red shells of Devonshire, may be found lying embedded in the same strata.

[AD] Silurian System, part i. p. 183.

The vegetable remains of the formation are numerous, but obscure, consisting mostly of carbonaceous markings, such as might be formed by comminuted sea-weed. (See [Plate VII.]) Some of the impressions fork into branches at acute angles, (see figs. 4, 5, and 6;) some affect a waved outline, (see figs. 7 and 8;) most of them, however, are straight and undivided. They lie in some places so thickly in layers as to give the stone in which they occur a slaty character. One of my specimens shows minute markings, somewhat resembling the bird-like eyes of the Stigmaria Ficoides of the Coal Measures;—the branches of another terminate in minute hooks, that remind one of the hooks of the young tendrils of the pea when they first begin to turn. (See fig. 3.) In yet another there are marks of the ligneous fibre; when examined by the glass, it resembles a bundle of horse-hairs lying stretched in parallel lines; and in this specimen alone have I found aught approaching to proof of a terrestrial origin. The deposition seems to have taken place far from land; and this lignite, if in reality such, had probably drifted far ere it at length became weightier than the supporting fluid, and sank.[AE] It is by no means rare to find fragments of wood that have been borne out to sea by the gulf stream from the shores of Mexico or the West Indian Islands, stranded on the rocky coasts of Orkney and Shetland.

[AE] The organism here referred to has been since slit by the lapidary, and the sections carefully examined. It proves to be unequivocally a true wood of the coniferous class. The following is the decision regarding it of Mr. William Nicol, of Edinburgh, confessedly one of our highest living authorities in that division of fossil botany which takes cognizance of the internal structure cf lignites, and decides from their anatomy their race and family:—

Edinburgh, 19th July, 1815.

Dear Sir:—I have examined the structure of the fossil wood which you found in the Old Red Sandstone at Cromarty, and have no hesitation in stating, that the reticulated texture of the transverse sections, though somewhat compressed, clearly indicates a coniferous origin; but as there is not the slightest trace of a disk to be seen in the longitudinal sections parallel to the medullary rays, it is impossible to say whether it belongs to the Pine or Araucarian division. I am, &c.,

William Nicol.

The dissimilarity which obtains between the fossils of the contemporary formations of this system in England and Scotland, is instructive. The group in the one consists mainly of molluscous animals; in the other, almost entirely of ichthyolites, and what seems to have been algæ. Other localities may present us with yet different groups of the same period—with the productions of its coasts, its lakes, and its rivers. At present, we are but beginning to know just a little of its littoral shells, and of the fish of its profounder depths. These last are surely curious subjects of inquiry. We cannot catechise our stony ichthyolites, as the necromantic lady of the Arabian Nights did the colored fish of the lake, which had once been a city, when she touched their dead bodies with her wand, and they straightway raised their heads and replied to her queries. We would have many a question to ask them if we could—questions never to be solved. But even the contemplation of their remains is a powerful stimulant to thought. The wonders of Geology exercise every faculty of the mind—reason; memory, imagination; and though we cannot put our fossils to the question, it is something to be so aroused as to be made to put questions to one's self. I have referred to the consistency of style which obtained among these ancient fishes—the unity of character which marked every scale, plate, and fin of every various family, and which distinguished it from the rest; and who can doubt that the same shades of variety existed in their habits and their instincts? We speak of the infinity of Deity—of his inexhaustible variety of mind; but we speak of it until the idea becomes a piece of mere common-place in our mouths. It is well to be brought to feel, if not to conceive of it—to be made to know that we ourselves are barren-minded, and that in Him "all fulness dwelleth." Succeeding creations, each with its myriads of existences, do not exhaust Him. He never repeats Himself. The curtain drops, at his command, over one scene of existence full of wisdom and beauty; it rises again, and all is glorious, wise, and beautiful as before, and all is new, Who can sum up the amount of wisdom whose record He has written in the rocks—wisdom exhibited in the succeeding creations of earth, ere man was, but which was exhibited surely not in vain? May we not say with Milton,—

Think not, though men were none,
That heaven could want spectators, God want praise;
Millions of spiritual creatures walked the earth,
And these with ceaseless praise his works beheld?