Lord Bacon remarks, “Some men think that the gratification of curiosity is the end of knowledge, some the love of fame, some the pleasure of dispute, and some the necessity of supporting themselves by knowledge; but the real use of all knowledge is this, that we should dedicate that reason which was given us by God to the use and advantage of man.” The historian of the old red sandstone, Hugh Miller, to whose researches not only we, but such men as Murchison, Lyell, Ansted, Agassiz and others, are so exclusively indebted, is a philosopher in this last category. He does not hesitate to tell us, how, as a Cromarty quarryman “twenty years ago,” he commenced a “life of labour and restraint,” a “slim, loose-jointed boy, fond of the pretty intangibilities of romance, and of dreaming when broad awake;”^[35] and how, as a quarryman, he ever kept his eyes open, to observe the results of every blow of the hammer, stroke of the pick, or blast of the powder; and finding himself in the midst of new and undreamt-of relics of an old creation, preserved in “tables of stone,” he adds his testimony to that of the great father of inductive philosophy, “that 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.”^[36]

We here enter upon a marvellous field of discovery. Hitherto the forms of life we have met with have all been invertebrate. The trilobite, something between a crab and a beetle, once revelling, in untold myriads, probably on the land as well as in the water, and of which two hundred and fifty species have been brought to light, is the highest type of life with which our researches have made us familiar. We are now to begin the study of fossil fish, and to their discovery, strange forms, and characters, this chapter will be specially devoted. It was once a generally received opinion among even the most learned geologists, that the “old red sandstone,” or the “Devonian system,” was particularly barren of fossils, but the labours (literally such, “mente, manu, malleoque”^[37]) of Hugh Miller have proved the contrary. “The fossils,” he says, “are remarkably numerous, and in a state of high preservation. I have a hundred solid proofs by which to establish the proof of my 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 certainty 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 armour 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.”^[38]

The old red sandstone formation prevails in the north of Scotland, Herefordshire, north of Devonshire, part of Cornwall, and in Worcestershire and Shropshire. Our attention will be principally confined to Cromarty, whose romantic bay and high hills have long arrested the admiring gaze of the traveller. This was the scene of Hugh Miller’s labours and discoveries; this the great library in which he read the history of pre-Adamite ichthyolites^[39] exposed not only to the light of day, but for the first time to the inspection of human eyes, by the sweat-of-brow toil of one of Scotland’s noble sons. Before we get into the hard names that must be connected with this chapter, let us hear Mr. Miller describe this library of God’s books that was so long his wonder and his study in Cromartyshire. “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. Not the united labours of a thousand men for a thousand years could have furnished a better section of the geology of this 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, its huge masses of horneblend; 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 very interesting fossils of the old red sandstone in one deposition; we find the beautifully preserved shell 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, hyperstenes, 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 best I might, and find out all its wonders for myself. But so slow was the process, and so much was I a seeker in the dark, that the facts contained in these few sentiments were the patient gatherings of years.”^[40]

Now with regard to the hard names to which we have just made allusion—names that, apart from their etymology, which is nothing more than “sending vagrant words back to their parish,” are enough to startle any one; names such as heterocercal, homocercal, cephalaspis, pterichthys, coccosteus, osteolepis, &c. &c.—why, they will all presently become plain, and, we hope, familiar to our readers. “They are,” says Hugh Miller, “like all names in science, unfamiliar in their aspect 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.”^[41]

The rest of this chapter will be occupied with an account of the four most remarkable and characteristic fishes of this formation, to understand which a few preliminary remarks are necessary. Cuvier divided all fish into two groups, the bony and the cartilaginous; and these two groups he subdivided into two divisions, characterised by differences in their fins, or organs of locomotion, one of which he called Acanthopterygian,^[42] (thorny-finned,) and the other, Malacopterygian,^[43] (or soft-finned.) This concise arrangement did not, however, meet all the wants of the fish-students, and it was often practically difficult to know under which class to arrange particular specimens. More recently M. Agassiz has arranged fish, not according to their fins, but according to their scales; and simple as this classification may seem, it is one of the greatest triumphs of genius in modern times, inasmuch as all fishes extinct and existing, that have inhabited or are inhabiting the “waters under the earth,” may be grouped easily under the following four divisions:—

One more preliminary remark, and we will proceed to look at the four fishes already alluded to. Neither the teacher nor the student of any science can skip definitions, axioms, postulates, and so on; they must just be mastered, and their mastery is a real pleasure. In addition to a marked difference in the fins, a difference was observed also in the tails of fossil (extinct) and living pieces of fish. This difference between the tails of fish has been happily described in two words, heterocercal and homocercal, of which the figures below will give a better idea than a lengthened description.

The heterocercal fish, it will be seen, are unequally lobed, that is, the spinal vertebræ are prolonged into the upper lobe of the tail, as seen in the shark, and of which our own dog-fish is an example; while the homocercal fish are equally lobed, and the spine does not extend into either.

The fossil fish of the old red sandstone belong almost, if not entirely, to the classes of fish that have ganoid or placoid scales, and heterocercal tails; and of these fish we will now say a few words of the four most remarkable specimens of the one thousand and upwards fossil species that have been discovered, and which can only be known familiarly by accomplished geologists in the ichthyolite department.

1. Here is a drawing of the Cephalaspis,^[48] or buckler-headed fish. What an extraordinary looking creature this is! Like the crescent shape of a saddler’s knife without the handle—broad and flat, with points on each side running down, ever fixed in warlike attitude against its enemies—it reminds one of an extinct trilobite, and of a living sole or ray, at the same time; and one can easily fancy how hard it must have been for its ancient foes to swallow down so singular and so knife-like looking a creature. This is one of the curious organisms of old life discovered in Cromarty, Herefordshire, and in Russia, the original of which, restored in the drawing, seldom if ever exceeded seven inches.

Let us look now at another curiosity from the same quarter.

2. Here is a drawing of the Coccosteus,^[49] or berry-boned fish. This creature is equally singular with his long extinct neighbour. Hugh Miller’s description is the best, and as he was its discoverer, let us give it.

“The figure of the Coccosteus I would compare to a boy’s kite; 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. A ring of plates, like the ring-stones of an arch, runs along what we may call the hoop of the kite. The form of the key-stone 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.”^[50]

3. Above is the Pterichthys,^[51] or winged fish. We have here a fish more strikingly different to any existing species than either of the other two just passed under review. “Imagine,” says Miller, “the figure of a man rudely drawn in black on a grey ground; the head cut off by 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; the other, as if to preserve the balance, placed directly in the centre of the figure, which it seems to support. Such, at the first glance, is the appearance of the fossil.”^[52]

We will now turn to the fourth and last of the singular fishes of this formation.

4. The Osteolepis,^[53] or bony scaled fish. Here we have in the old red sandstone the first perfect specimen of a fish with pectoral, abdominal, and caudal fins, ending as the others do in the heterocercal tail. 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 such as the naked skull, jaws, and operculum,^[54] 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.^[55]

Most hasty and superficial is this glance through the wonders of the old red sandstone. On the economic uses of this formation, as tile-stones and paving-stones, we need not dwell; apart from this, these singular inhabitants of the seas of past ages, the mud of which, elevated and hardened, has become solid rock, tell us stories of that long since ancient time to which no poetry could do justice. Carried away from the present into those remote eras, our minds revel in the realization of scenery and inhabitants, of which now we possess only the fossil pictures. At the British Museum, we gaze with feelings approaching to repulsion on the stiff and unnatural forms of Egyptian mummies, but with what feelings of profound wonder do we look on these small fishes, so numerous that the relics of them, found in the Orkneys, may be carried away by cartloads! No number of creations can exhaust God, for in Him all fulness dwelleth. The God in whom we now live, and move, and have our being, is the same God who gave to these pre-Adamite fish their marvellous structures, minutely but fearfully and wonderfully made, and who, when their joy of life and functions of life had ceased, consigned them to a calm and peaceful grave. He is the same God who now upholds all things by the word of his power, and whom we desire to honour by the attentive and reverent perusal of his manifold works. We are tautologists; we say and do the same thing over and over again. God never repeats himself: each successive creation—and how many, extending through countless ages, does geology disclose!—only reveals some new aspect of wisdom, love, and beneficence. To the mind that cannot repose in God, we say, Study God, in his works and in his word; yea, come back to this remote sandstone era and ask of the “fishes, and they shall declare unto thee” the might and majesty, the skill and contrivance of the Almighty; and though you and I were not there, nor had Adam yet trod this blessed earth,—