CHAPTER III.
Structure of the Scuir—A stray Column—The Piazza—A buried Pine Forest the Foundation of the Scuir—Geological Poachers in a Fossil Preserve—Pinites Eiggensis—Its Description—Witham's Experiments on Fossil Pine of Eigg—Rings of the Pine—Ascent of the Scuir—Appearance of the Top—White Pitchstone—Mr. Greig's Discovery of Pumice—A Sunset Scene—The Manse and the Yacht—The Minister's Story—A Cottage Repast—American Timber drifted to the Hebrides—Agency of the Gulf Stream—The Minister's Sheep.
As we climbed the hill-side, and the Shinar-like tower before us rose higher over the horizon at each step we took, till it seemed pointing at the middle sky, we could mark peculiarities in its structure which escape notice in the distance. We found it composed of various beds, each of which would make a Giant's Causeway entire, piled over each other like stories in a building, and divided into columns, vertical, or nearly so, in every instance except in one bed near the base, in which the pillars incline to a side, as if losing footing under the superincumbent weight. Innumerable polygonal fragments,—single stones of the building,—lie scattered over the slope, composed, like almost all the rest of the Scuir, of a peculiar and very beautiful stone, unlike any other in Scotland—a dark pitchstone-porphyry, which, inclosing crystals of glassy feldspar, resembles in the hand-specimen, a mass of black sealing-wax, with numerous pieces of white bugle stuck into it. Some of the detached polygons are of considerable size; few of them larger and bulkier, however, than a piece of column of this characteristic porphyry, about ten feet in length by two feet in diameter, which lies a full mile away from any of the others, in the line of the old burying-ground, and distant from it only a few hundred yards. It seems to have been carried there by man: we find its bearing from the Scuir lying nearly at right angles with the direction of the drift-boulders of the western coast, which are, besides, of rare occurrence in the Hebrides; nor has it a single neighbor; and it seems not improbable, as a tradition of the island testifies, that it was removed thus far for the purpose of marking some place of sepulture, and that the catastrophe of the cave arrested its progress after by far the longer and rougher portion of the way had been passed. The dry-arm bones of the charnel-house in the rock may have been tugging around it when the galleys of the M'Leod hove in sight. The traditional history of Eigg, said my friend the minister, compared with that of some of the neighboring islands, presents a decapitated aspect: the M'Leods cut it off by the neck. Most of the present inhabitants can tell which of their ancestors, grandfather, or great-grandfather, or great-great-grandfather, first settled in the place, and where they came from; and, with the exception of a few vague legends about St. Donan and his grave, which were preserved apparently among the people of the other Small Isles, the island has no early traditional history.
We had now reached the Scuir. There occur, intercalated with the columnar beds, a few bands of a buff-colored non-columnar trap, described by M'Culloch as of a texture intermediate between a greenstone and a basalt, and which, while the pitchstone around it seems nearly indestructible, has weathered so freely as to form horizontal grooves along the face of the rock, from two to five yards in depth. One of these runs for several hundred feet along the base of the Scuir, just at the top of the talus, and greatly resembles a piazza, lacking the outer pillars. It is from ten to twelve feet in height, by from fifteen to twenty in depth; the columns of the pitch stone-bed immediately above it seem perilously hanging in mid air; and along their sides there trickles, in even the driest summer weather,—for the Scuir is a condenser on an immense scale—minute runnels of water, that patter ceaselessly in front of the long deep hollow, like rain from the eaves of a cottage during a thunder shower. Inside, however, all is dry, and the floor is covered to the depth of several inches with the dung of sheep and cattle, that find, in this singular mountain piazza, a place of shelter. We had brought a pickaxe with us; and the dry and dusty floor, composed mainly of a gritty conglomerate, formed the scene of our labors. It is richly fossiliferous, though the organisms have no specific variety; and never, certainly, have I found the remains of former creations in a scene in which they more powerfully addressed themselves to the imagination. A stratum of peat-moss, mixed with fresh-water shells, and resting on a layer of vegetable mould, from which the stumps and roots of trees still protruded, was once found in Italy, buried beneath an ancient tesselated pavement; and the whole gave curious evidence of a kind fitted to picture to the imagination a background vista of antiquity, all the more remotely ancient in aspect from the venerable age of the object in front. Dry ground covered by wood, a lake, a morass, and then dry ground again, had all taken precedence, on the site of the tesselated pavement, in this instance, of an old Roman villa. But what was antiquity in connection with a Roman villa, to antiquity in connection with the Scuir of Eigg? Under the old foundations of this huge wall we find the remains of a pine forest, that, long ere a single bed of the porphyry had burst from beneath, had sprung up and decayed on hill and beside stream in some nameless land,—had then been swept to the sea,—had been entombed deep at the bottom in a grit of Oölite,—had been heaved up to the surface, and high over it, by volcanic agencies working from beneath,—and had finally been built upon, as moles are built upon piles, by the architect that had laid down the masonry of the gigantic Scuir, in one fiery layer after another. The mountain wall of Eigg, with its dizzy elevation of four hundred and seventy feet, is a wall founded on piles of pine laid crossways; and, strange as the fact may seem, one has but to dig into the floor of this deep-hewn piazza, to be convinced that at least it is a fact.
Just at this interesting stage, however, our explorations bade fair to be interrupted. Our man who carried the pickaxe had lingered behind us for a few hundred yards, in earnest conversation with an islander; and he now came up, breathless and in hot haste, to say that the islander, a Roman Catholic tacksman in the neighborhood, had peremptorily warned him that the Scuir of Eigg was the property of Dr. M'Pherson of Aberdeen, not ours, and that the Doctor would be very angry at any man who meddled with it. "That message," said my friend, laughing, but looking just a little sad through the laugh, "would scarce have been sent us when I was minister of the Establishment here; but it seems allowable in the case of a poor Dissenter, and is no bad specimen of the thousand little ways in which the Roman Catholic population of the island try to annoy me, now that they see my back to the wall." I was tickled with the idea of a fossil preserve, which coupled itself in my mind, through a trick of the associative faculty, with the idea of a great fossil act for the British empire, framed on the principles of the game-laws; and, just wondering what sort of disreputable vagabonds geological poachers would become under its deteriorating influence, I laid hold of the pickaxe and broke into the stonefast floor; and thence I succeeded in abstracting,—feloniously, I dare say, though the crime has not yet got into the statute-book—some six or eight pieces of the Pinites Eiggensis, amounting in all to about half a cubic foot of that very ancient wood—value unknown. I trust, should the case come to a serious bearing, the members of the London Geological Society will generously subscribe half-a-crown a-piece to assist me in feeing counsel. There are more interests than mine at stake in the affair. If I be cast and committed,—I, who have poached over only a few miserable districts in Scotland,—pray, what will become of some of them,—the Lyells, Bucklands, Murchisons and Sedgwicks,—who have poached over whole continents?
We were successful in procuring several good specimens of the Eigg pine, at a depth, in the conglomerate, of from eight to eighteen inches. Some of the upper pieces we found in contact with the decomposing trap out of which the hollow piazza above had been scooped; but the greater number, as my set of specimens abundantly testify, lay embedded in the original Oölitic grit in which they had been locked up, in, I doubt not, their present fossil state, ere their upheaval, through Plutonic agency, from their deep-sea bottom. The annual rings of the wood, which are quite as small as in a slow-growing Baltic pine, are distinctly visible in all the better pieces I this day transferred to my bag. In one fragment I reckon sixteen rings in half an inch, and fifteen in the same space in another. The trees to which they belonged seem to have grown on some exposed hill-side, where, in the course of half a century, little more than from two or three inches were added to their diameter. The Pinites Eiggensis, or Eigg pine, was first introduced to the notice of the scientific world by the late Mr. Witham, in whose interesting work on "The Internal Structure of Fossil Vegetables" the reader may find it figured and described. The specimen in which he studied its peculiarities "was found," he says, "at the base of the magnificent mural escarpment named the Scuir of Eigg,—not, however, in situ, but among fragments of rocks of the Oölitic series." The authors of the "Fossil Flora," where it is also figured, describe it as differing very considerably in structure from any of the coniferæ of the Coal Measures. "Its medullary rays," says Messrs. Lindley and Hutton, "appear to be more numerous, and frequently are not continued through one zone of wood to another, but more generally terminate at the concentric circles. It abounds also in turpentine vessels, or lacunæ, of various sizes, the sides of which are distinctly defined." Viewed through the microscope, in transparent slips, longitudinal and transverse, it presents, within the space of a few lines, objects fitted to fill the mind with wonder. We find the minutest cells, glands, fibres, of the original wood preserved uninjured. There still are those medullary rays entire that communicated between the pith and the outside,—there still the ring of thickened cells that indicated the yearly check which the growth received when winter came on,—there the polygonal reticulations of the cross section, without a single broken mesh,—there, too, the elongated cells in the longitudinal one, each filled with minute glands that take the form of double circles,—there also, of larger size and less regular form, the lacunæ in which the turpentine lay: every nicely organized speck, invisible to the naked eye, we find in as perfect a state of keeping in the incalculably ancient pile-work on which the gigantic Scuir is founded, as in the living pines that flourish green on our hill-sides. A net-work, compared with which that of the finest lace ever worn by the fair reader would seem a net-work of cable, has preserved entire, for untold ages, the most delicate peculiarities of its pattern. There is not a mesh broken, nor a circular dot away!
The experiments of Mr. Witham on the Eigg fossil, furnish an interesting example of the light which a single, apparently simple, discovery may throw on whole departments of fact. He sliced his specimen longitudinally and across, fastened the slices on glass, ground them down till they became semi-transparent, and then, examining them under reflected light by the microscope, marked and recorded the specific peculiarities of their structure. And we now know, in consequence, that the ancient Eigg pine, to which the detached fragment picked up at the base of the Scuir belonged,—a pine alike different from those of the earlier carboniferous period and those which exist contemporary with ourselves,—was, some three creations ago, an exceedingly common tree in the country now called Scotland,—as much so, perhaps, as the Scotch fir is at the present day. The fossil trees found in such abundance in the neighborhood of Helmsdale that they are burnt for lime,—the fossil wood of Eathie, in Cromartyshire, and that of Shandwick, in Ross,—all belong to the Pinites Eiggensis. It seems to have been a straight and stately tree, in most instances, as in the Eigg specimens, of slow growth. One of the trunks I saw near Navidale measured two feet in diameter, but a full century had passed ere it attained to a bulk so considerable; and a splendid specimen in my collection, from the same locality, which measures twenty-one inches, exhibits even more than a hundred annual rings. In one of my specimens, and one only, the rings are of great breadth. They differ from those of all the others in the proportion in which I have seen the annual rings of a young, vigorous fir that had sprung up in some rich, moist hollow, differ from the annual rings of trees of the same species that had grown in the shallow, hard soil of exposed hill-sides. And this one specimen furnishes curious evidence that the often-marked but little understood law, which gives us our better and worse seasons in alternate groups, various in number and uncertain in their time of recurrence, obtained as early as the age of the Oölite. The rings follow each other in groups of lesser and larger breadth. One group of four rings measures an inch and a quarter across, while an adjoining group of five rings measures only five-eighth parts; and in a breadth of six inches there occur five of these alternate groups. For some four or five years together, when this pine was a living tree, the springs were late and cold, and the summers cloudy and chill, as in that group of seasons which intervened between 1835 and 1841; and then, for four or five years, more springs were early and summers genial, as in the after group of 1842, 1843 and 1844. An arrangement in nature,—first observed, as we learn from Bacon, by the people of the Low Countries, and which has since formed the basis of meteoric tables, and of predictions and elaborate cycles of the weather,—bound together the twelvemonths of the Oölitic period in alternate bundles of better and worse: vegetation throve vigorously during the summers of one group, and languished, in those of another, in a state of partial development.
Sending away our man shipwards, laden with a bag of fossil wood, we ascended by a steep broken ravine to the top of the Scuir. The columns, as we pass on towards the west, diminish in size, and assume in many of the beds considerable variety of direction and form. In one bed they belly over with a curve, like the ribs of some wrecked vessel from which the planking has been torn away; in another they project in a straight line, like muskets planted slantways on the ground to receive a charge of cavalry; in others the inclination is inwards, like that of ranges of stakes placed in front of a sea-dyke, to break the violence of the waves; while yet in others they present, as in the eastern portion of the Scuir, the common vertical direction. The ribbed appearance of every crag and cliff, imparts to the scene a peculiar character; every larger mass of light and shadow is corded with minute stripes; and the feeling experienced among the more shattered peaks, and in the more broken recesses, seems near akin to that which it is the tendency of some magnificent ruin to excite, than that which awakens amid the sublime of nature. We feel as if the pillared rocks around us were like the Cyclopean walls of Southern Italy,—the erections of some old gigantic race passed from the earth forever. The feeling must have been experienced on former occasions, amid the innumerable pillars of the Scuir; for we find M'Culloch, in his description, ingeniously analyzing it. "The resemblance to architecture here is much increased," he says, "by the columnar structure, which is sufficiently distinguishable, even from a distance, and produces a strong effect of artificial regularity when seen near at hand. To this vague association in the mind of the efforts of art with the magnitude of nature, is owing much of that sublimity of character which the Scuir presents. The sense of power is a fertile source of the sublime; and as the appearance of power exerted, no less than that of simplicity, is necessary to confer this character on architecture, so the mind, insensibly transferring the operations of nature to the efforts of art where they approximate in character, becomes impressed with a feeling rarely excited by her more ordinary forms, where these are even more stupendous."
The top of the Scuir, more especially towards its eastern termination, resembles that of some vast mole not yet levelled over by the workmen; the pavement has not yet been laid down, and there are deep gaps in the masonry, that run transversely, from side to side, still to fill up. Along one of these ditch-like gaps, which serves to insulate the eastern and highest portion of the Scuir from all its other portions, we find fragments of a rude wall of uncemented stones, the remains of an ancient hill-fort; which, with its natural rampart of rock on three of its four sides, more than a hundred yards in sheer descent, and with its deep ditch and rude wall on the fourth, must have formed one of the most inaccessible in the kingdom. The masses of pitchstone a-top, though so intensely black within, are weathered on the surface into almost a pure white; and we found lying detached among them, fragments of common amygdaloid and basalt, and minute slaty pieces of chalcedony that had formed apparently in fissures of the trap. We would have scrutinized more narrowly at the time had we expected to find anything more rare; but I did not know until full four months after, that aught more rare was to be found. Had we examined somewhat more carefully, we might possibly have done what Mr. Woronzow Greig did on the Scuir about eighteen years previous,—picked up on it a piece of bona fide Scotch pumice. This gentleman, well known through his exertions in statistical science, and for his love of science in general, and whose tastes and acquirements are not unworthy the son of Mrs. Somerville, has kindly informed me by letter regarding his curious discovery. "I visited the island of Eigg," he says, "in 1825 or 1826, for the purpose of shooting, and remained in it several days; and as there was a great scarcity of game, I amused myself in my wanderings by looking about for natural curiosities. I knew little about Geology at the time, but, collecting whatever struck my eye as uncommon, I picked up from the sides of the Scuir, among various other things, a bit of fossil wood, and, nearly at the summit of the eminence, a piece of pumice of a deep brownish-black color, and very porous, the pores being large and round, and the substance which divided them of a uniform thickness. This last specimen I gave to Mr. Lyell, who said that it could not originally have belonged to Eigg, though it might possibly have been washed there by the sea,—a suggestion, however, with which its place on the top of the Scuir seems ill to accord. I may add, that I have since procured a larger specimen from the same place." This seems a curious fact, when we take into account the identity, in their mineral components, of the pumice and obsidian of the recent volcanoes; and that pitchstone, the obsidian of the trap-rocks, is resolvable into a pumice by the art of the chemist. If pumice was to be found anywhere in Scotland, we might a priori expect to find it in connection with by far the largest mass of pitchstone in the kingdom. It is just possible, however, that Mr. Greig's two specimens may not date farther back, in at least their existing state, than the days of the hill-fort. Powerful fires would have been required to render the exposed summit of the Scuir at all comfortable; there is a deep peat-moss in its immediate neighborhood, that would have furnished the necessary fuel; the wind must have been sufficiently high on the summit to fan the embers into an intense white heat; and if it was heat but half as intense as that which was employed in fusing into one mass the thick vitrified ramparts of Craig Phadrig and Knock Farril, on the east coast, it could scarce have failed to anticipate the experiment of the Hon. Mr. Knox, of Dublin, by converting some of the numerous pitchstone fragments that lie scattered about, "into a light substance in every respect resembling pumice."
It was now evening, and rarely have I witnessed a finer. The sun had declined half-way adown the western sky, and for many yards the shadow of the gigantic Scuir lay dark beneath us along the descending slope. All the rest of the island, spread out at our feet as in a map, was basking in yellow sunshine; and with its one dark shadow thrown from its one mountain-elevated wall of rock, it seemed some immense fantastical dial, with its gnomon rising tall in the midst. Far below, perched on the apex of the shadow, and half lost in the line of the penumbra, we could see two indistinct specks of black, with a dim halo around each,—specks that elongated as we arose, and contracted as we sat, and went gliding along the line as we walked. The shadows of two gnats disporting on the edge of an ordinary gnomon would have seemed vastly more important, in proportion, on the figured plane of the dial, than these, our ghostly representatives, did here. The sea, spangled in the wake of the sun with quick glancing light, stretched out its blue plain around us; and we could see included in the wide prospect, on the one hand, at once the hill-chains of Morven and Kintail, with the many intervening lochs and bold jutting headlands that give variety to the mainland; and, on the other, the variously complexioned Hebrides, from the Isle of Skye to Uist and Barra, and from Uist and Barra to Tiree and Mull. The contiguous Small Isles, Muck and Rum, lay moored immediately beside us, like vessels of the same convoy that in some secure roadstead drop anchor within hail of each other. I could willingly have lingered on the top of the Scuir until after sunset; but the minister, who, ever and anon, during the day, had been conning over some notes jotted on a paper of wonderfully scant dimensions, reminded me that this was the evening of his week-day discourse, and that we were more than a particularly rough mile from the place of meeting, and within, half an hour of the time. I took one last look of the scene ere we commenced our descent. There, in the middle of the ample parish glebe, that looked richer and greener in the light of the declining sun than at any former period during the day,—rose the snug parish manse; and yonder,—in an open island channel, with a strip of dark rocks fringing the land within, and another dark strip fringing the barren Eilean Chaisteil outside,—lay the Betsey, looking wonderfully diminutive, but evidently a little thing of high spirit, taut-masted, with a smart rake aft, and a spruce outrigger astern, and flaunting her triangular flag of blue in the sun. I pointed first to the manse, and then to the yacht. The minister shook his head.