The Old Red Sandstone; or, New Walks in an Old Field

by Hugh Miller

The first scene in the Tempest opens amid the confusion and turmoil of the hurricane—amid thunders and lightnings, the roar of the wind, the shouts of the seamen, the rattling of cordage, and the wild dash of the billows. The history of the period represented by the Old Red Sandstone seems, in what now forms the northern half of Scotland, to have opened in a similar manner. The finely-laminated lower Tilestones of England were deposited evidently in a calm sea. During the contemporary period in our own country, the vast space which now includes Orkney and Loch Ness, Dingwall, and Gamrie, and many a thousand square mile besides, was the scene of a shallow ocean, perplexed by powerful currents, and agitated by waves. A vast stratum of water-rolled pebbles, varying in depth from a hundred feet to a hundred yards, remains in a thousand different localities, to testify of the disturbing agencies of this time of commotion. The hardest masses which the stratum encloses,—porphyries of vitreous fracture that cut glass as readily as flint, and masses of quartz that strike fire quite as profusely from steel,—are yet polished and ground down into bullet-like forms, not an angular fragment appearing in some parts of the mass for yards together. The debris of our harder rocks rolled for centuries in the beds of our more impetuous rivers, or tossed for ages along our more exposed and precipitous sea-shores, could not present less equivocally the marks of violent and prolonged attrition than the pebbles of this bed. And yet it is surely difficult to conceive how the bottom of any sea should have been so violently and so equally agitated for so greatly extended a space as that which intervenes between Mealforvony in Inverness-shire and Pomona in Orkney in one direction, and between Applecross and Trouphead in another—and for a period so prolonged, that the entire area should have come to be covered with a stratum of rolled pebbles of almost every variety of ancient rock, fifteen stories' height in thickness. The very variety of its contents shows that the period must have been prolonged. A sudden flood sweeps away with it the accumulated debris of a range of mountains; but to blend together, in equal mixture, the debris of many such ranges, as well as to grind down their roughnesses and angularities, and fill up the interstices with the sand and gravel produced in the process, must be a work of time. I have examined with much interest, in various localities, the fragments of ancient rock inclosed in this formation. Many of them are no longer to be found in situ, and the group is essentially different from that presented by the more modern gravels. On the shores of the Frith of Cromarty, for instance, by far the most abundant pebbles are of a blue schistose gneiss: fragments of gray granite and white quartz are also common; and the sea-shore at half ebb presents at a short distance the appearance of a long belt of bluish gray, from the color of the prevailing stones which compose it. The prevailing color of the conglomerate of the district, on the contrary, is a deep red. It contains pebbles of small-grained, red granite, red quartz rock, red feldspar, red porphyry, an impure red jasper, red hornstone, and a red granitic gneiss, identical with the well-marked gneiss of the neighboring Sutors. This last is the only rock now found in the district, of which fragments occur in the conglomerate. It must have been exposed at the time to the action of the waves, though afterwards buried deep under succeeding formations, until again thrust to the surface by some great internal convulsion, of a date comparatively recent.[BA]

[BA] The vast beds of unconsolidated gravel with which one of the later geological revolutions has half filled some of our northern valleys, and covered the slopes of the adjacent hills, present, in a few localities, appearances somewhat analogous to those exhibited by this ancient formation. There are uncemented accumulations of water-rolled pebbles, in the neighborhood of Inverness, from ninety to a hundred feet in thickness. But this stratum, unlike the more ancient one, wanted continuity. It must have been accumulated, too, under the operation of more partial, though immensely more powerful agencies. There is a mediocrity of size in the enclosed fragments of the old conglomerate, which gives evidence of a mediocrity of power in the transporting agent. In the upper gravels, on the contrary, one of the agents could convey from vast distances blocks of stone eighty and a hundred tons in weight. A new cause of tremendous energy had come into operation in the geological world.

The period of this shallow and stormy ocean passed. The bottom, composed of the identical conglomerate which now forms the summit of some of our loftiest mountains, sank throughout its wide area to a depth so profound as to be little affected by tides or tempests. During this second period there took place a vast deposit of coarse sandstone strata, with here and there a few thin beds of rolled pebbles. The general subsidence of the bottom still continued, and, after a deposit of full ninety feet had overlain the conglomerate, the depth became still more profound than at first. A fine, semi-calcareous, semi-aluminous deposition took place in waters perfectly undisturbed. And here we first find proof that this ancient ocean literally swarmed with life—that its bottom was covered with miniature forests of algæ, and its waters darkened by immense shoals of fish.

In middle autumn, at the close of the herring season, when the fish have just spawned, and the congregated masses are breaking up on shallow and skerry, and dispersing by myriads over the deeper seas, they rise at times to the surface by a movement so simultaneous, that for miles and miles around the skiff of the fisherman nothing may be seen but the bright glitter of scales, as if the entire face of the deep were a blue robe spangled with silver. I have watched them at sunrise at such seasons on the middle of the Moray Frith, when, far as the eye could reach, the surface has been ruffled by the splash of fins, as if a light breeze swept over it, and the red light has flashed in gleams of an instant on the millions and tens of millions that were leaping around me, a handbreadth into the air, thick as hail-stones in a thunder-shower. The amazing amount of life which the scene included, has imparted to it an indescribable interest. On most occasions the inhabitants of ocean are seen but by scores and hundreds; for in looking down into their green twilight haunts, we find the view bounded by a few yards, or at most a few fathoms; and we can but calculate on the unseen myriads of the surrounding expanse by the seen few that occupy the narrow space visible. Here, however, it was not the few, but the myriads, that were seen—the innumerable and inconceivable whole—all palpable to the sight as a flock on a hill-side; or, at least, if all was not palpable, it was only because sense has its limits in the lighter as well as in the denser medium—that the multitudinous distracts it, and the distant eludes it, and the far horizon bounds it. If the scene spoke not of infinity in the sense in which Deity comprehends it, it spoke of it in at least the only sense in which man can comprehend it.

Now, we are much in the habit of thinking of such amazing multiplicity of being—when we think of it at all—with reference to but the later times of the world's history. We think of the remote past as a time of comparative solitude. We forget that the now uninhabited desert was once a populous city. Is the reader prepared to realize, in connection with the Lower Old Red Sandstone—the second period of vertebrated existence—scenes as amazingly fertile in life as the scene just described—oceans as thoroughly occupied with being as our friths and estuaries when the herrings congregate most abundantly on our coasts? There are evidences too sure to be disputed that such must have been the case. I have seen the ichthyolite beds, where washed bare in the line of the strata, as thickly covered with oblong, spindle-shaped nodules as I have ever seen a fishing bank covered with herrings; and have ascertained that every individual nodule had its nucleus of animal matter—that it was a stone coffin in miniature, holding enclosed its organic mass of bitumen or bone—its winged, or enamelled, or thorn-covered ichthyolite.

At this period of our history, some terrible catastrophe involved in sudden destruction the fish of an area at least a hundred miles from boundary to boundary, perhaps much more. The same platform in Orkney as at Cromarty is strewed thick with remains, which exhibit unequivocally the marks of violent death. The figures are contorted, contracted, curved; the tail in many instances is bent round to the head; the spines stick out; the fins are spread to the full, as in fish that die in convulsions. The Pterichthys shows its arms extended at their stiffest angle, as if prepared for an enemy. The attitudes of all the ichthyolites on this platform are attitudes of fear, anger, and pain. The remains, too, appear to have suffered nothing from the after attacks of predaceous fishes; none such seem to have survived. The record is one of destruction at once widely spread and total, so far as it extended. There are proofs that, whatever may have been the cause of the catastrophe, it must have taken place in a sea unusually still. The scales, when scattered by some slight undulation, are scattered to the distance of only a few inches, and still exhibit their enamel entire, and their peculiar fineness of edge. The spines, even when separated, retain their original needle-like sharpness of point. Rays, well nigh as slender as horse-hairs, are enclosed unbroken in the mass. Whole ichthyolites occur, in which not only all the parts survive, but even the expression which the stiff and threatening attitude conveyed when the last struggle was over. Destruction must have come in the calm, and it must have been of a kind by which the calm was nothing disturbed. In what could it have originated? By what quiet but potent agency of destruction were the innumerable existences of an area perhaps ten thousand square miles in extent annihilated at once, and yet the medium in which they had lived left undisturbed by its operations? Conjecture lacks footing in grappling with the enigma, and expatiates in uncertainty over all the known phenomena of death. Diseases of mysterious origin break out at times in the animal kingdom, and well nigh exterminate the tribes on which they fall. The present generation has seen a hundred millions of the human family swept away by a disease unknown to our fathers. Virgil describes the fatal murrain that once depopulated the Alps, not more as a poet than as a historian. The shell-fish of the rivers of North America died in such vast abundance during a year of the present century, that the animals, washed out of their shells, lay rotting in masses beside the banks, infecting the very air. About the close of the last century, the haddock well nigh disappeared, for several seasons together, from the eastern coasts of Scotland; and it is related by Creech, that a Scotch shipmaster of the period sailed for several leagues on the coast of Norway, about the time the scarcity began, through a floating shoal of dead haddocks.[BB]

[BB] I have heard elderly fishermen of the Moray Frith state, in connection with what they used to term "the haddock dearth" of this period, that, for several weeks ere the fish entirely disappeared, they acquired an extremely disagreeable taste, as if they had been boiled in tobacco juice, and became unfit for the table. For the three following years they were extremely rare on the coast, and several years more elapsed ere they were caught in the usual abundance. The fact related by Creech, a very curious one, I subjoin in his own words; it occurs in his third Letter to Sir John Sinclair: "On Friday, the 4th December, 1789, the ship Brothers, Captain Stewart, arrived at Leith from Archangel, who reported that, on the coast of Lapland and Norway, he sailed many leagues through immense quantities of dead haddocks floating on the sea. He spoke several English ships, who reported the same fact. It is certain that haddocks, which was the fish in the greatest abundance in the Edinburgh market, have scarcely been seen there these three years. In February, 1790, three haddocks were brought to market, which, from their scarcity, sold for 7s. 6d."

The dead haddocks seen by the Leith shipmaster were floating by thousands; and most of their congeners among what fishermen term "the white fish," such as cod, ling, and whiting, also float when dead; whereas the bodies of fish whose bowels and air-bladders are comparatively small and tender, lie at the bottom. The herring fisherman, if the fish die in his nets, finds it no easy matter to buoy them up; and if the shoal entangled be a large one, he fails at times, from the great weight, in recovering them at all, losing both nets and herrings. Now, if a corresponding difference obtained among fish of the extinct period—if some rose to the surface when they died, while others remained at the bottom—we must, of course, expect to find their remains in very different degrees of preservation—to find only scattered fragments of the floaters, while of the others many may occur comparatively entire. Even should they have died on the same beds, too, we may discover their remains separated by hundreds of miles. The haddocks that disappeared from the coast of Britain were found floating in shoals on the coasts of Norway. The remains of an immense body of herrings, that weighed down, a few seasons since, the nets of a crew of fishermen, in a muddy hollow of the Moray Frith, and defied the utmost exertions of three crews united to weigh them from the bottom, are, I doubt not, in the muddy hollow still. On a principle thus obvious it may be deemed not improbable that the ichthyolites of the Lower Old Red Sandstone might have had numerous contemporaries, of which, unless in some instances the same accident which killed also entombed them, we can know nothing in their character as such, and whose broken fragments may yet be found in some other locality, where they may be regarded as characteristic of a different formation.

But the ravages of no such disease, however extensive, could well account for some of the phenomena of this platform of death. It is rarely that disease falls equally on many different tribes at once, and never does it fall with instantaneous, suddenness; whereas in the ruin of this platform from ten to twelve distinct genera seem to have been equally involved; and so suddenly did it perform its work, that its victims were fixed in their first attitude of terror and surprise. I have observed, too, that groups of adjoining nodules are charged frequently with fragments of the same variety of ichthyolite; and the circumstance seems fraught with evidence regarding both the original habits of the creatures, and the instantaneous suddenness of the destruction by which they were overtaken. They seem, like many of our existing fish, to have been gregarious, and to have perished together ere their crowds had time to break up and disperse.