: The Cruise of the Betsey or A Summer Ramble Among the Fossiliferous Deposits of the Hebrides. With Rambles of a Geologist or Ten Thousand Miles Over the Fossiliferous Deposits of Scotland by Miller Hugh Symonds W S William Samuel Editor - Geology Scotland

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he river expanded into the estuary, the estuary into the open sea; we left behind us beacon, and obelisk, and rock-perched castle;--

"Merrily down we drop Below the church, below the tower, Below the light house top,"

and, as the evening fell, we were ploughing the outer reaches of the Frith, with the ridgy table-land of Ayrshire stretching away, green, on the one side, and the serrated peaks of Arran rising dark and high on the other. At sunrise next morning our boat lay, unloading a portion of her cargo, in one of the ports of Islay, and we could see the Irish coast resting on the horizon to the south and west, like a long undulating bank of thin blue cloud; with the island of Rachrin--famous for the asylum it had afforded the Bruce when there was no home for him in Scotland,--presenting in front its mass of darker azure. On and away! We swept past Islay, with its low fertile hills of mica-schist and slate; and Jura, with its flat dreary moors, and its far-seen gigantic paps, on one of which, in the last age, Professor Walker, of Edinburgh, set water a-boil with six degrees of heat less than he found necessary for the purpose on the plain below. The Professor describes the view from the summit, which includes in its wide circle at once the Isle of Skye and the Isle of Man, as singularly noble and imposing; two such prospects more, he says, would bring under the eye the whole island of Great Britain, from the Pentland Frith to the English Channel. We sped past Jura. Then came the Gulf of Coryvrekin, with the bare mountain island of Scarba overlooking the fierce, far-famed whirlpool, that we could see from the deck, breaking in long lines of foam, and sending out its waves in wide rings on every side, when not a speck of white was visible elsewhere in the expanse of sea around us. And then came an opener space, studded with smaller islands,--mere hill-tops rising out of the sea, with here and there insulated groups of pointed rocks, the skeletons of perished hills, amid which the tide chafed and fretted, as if laboring to complete on the broken remains their work of denudation and ruin.

We left behind us the islands of Lunga, Luing, and Seil, and entered the narrow Sound of Kerrera, with its border of Old Red conglomerate resting on the clay-slate of the district. We had passed Esdaile near enough to see the workmen employed in the quarries of the island, so extensively known in commerce for their roofing slate, and several small vessels beside them, engaged in loading; and now we had got a step higher in the geological scale, and could mark from the deck the peculiar character of the conglomerate, which, in cliffs washed by the sea, when the binding matrix is softer than the pebbles which it encloses, roughens, instead of being polished, by the action of the waves, and which, along the eastern side of the Sound here, seems as if formed of cannon-shot, of all sizes, embedded in cement. The Sound terminates in the beautiful bay of Oban, so quiet and sheltered, with its two island breakwaters in front,--its semi-circular sweep of hill behind,--its long white-walled village, bent like a bow, to conform to the inflection of the shore,--its mural precipices behind, tapestried with ivy,--its rich patches of green pasture,--its bosky dingles of shrub and tree,--and, perched on the seaward promontory, its old, time-eaten keep. "In one part of the harbor of Oban," says Dr. James Anderson, in his "Practical Treatise on Peat Moss," , "where the depth of the sea is about twenty fathoms, the bottom is found to consist of quick peat, which affords no safe anchorage." I made inquiry at the captain of the steamer, regarding this submerged deposit, but he had never heard of it. There are, however, many such on the coasts of both Britain and Ireland. We staid at Oban for several hours, waiting the arrival of the Fort William steamer; and, taking out hammer and chisel from my bag, I stepped ashore to question my ancient acquaintance, the Old Red conglomerate, and was fortunate enough to meet on the pier-head, as I landed, one of the best of companions for assisting in such work, Mr. Colin Elder, of Isle Ornsay,--the gentleman who had so kindly furnished my friend Mr. Swanson with an asylum for his family, when there was no longer a home for them in Small Isles. "You are much in luck," he said, after our first greeting: "one of the villagers, in improving his garden, has just made a cut for some fifteen or twenty yards along the face of the precipice behind the village, and laid open the line of junction between the conglomerate and the clay-slate. Let us go and see it."

I found several things worthy of notice in the chance section to which I was thus introduced. The conglomerate lies uncomfortably along the edges of the slate strata, which present under it an appearance exactly similar to that which they exhibit under the rolled stones and shingle of the neighboring shore, where we find them laid bare beside the harbor, for several hundred yards. And, mixed with the pebbles of various character and origin of which the conglomerate is mainly composed, we see detached masses of the slate, that still exhibit on their edges the identical lines of fracture characteristic of the rock, which they received, when torn from the mass below, myriads of ages before. In the incalculably remote period in which the conglomerate base of the Old Red Sandstone was formed, the clay-slate of this district had been exactly the same sort of rock that it is now. Some long anterior convulsion had upturned its strata, and the sweep of water, mingled with broken fragments of stone, had worn smooth the exposed edges, just as a similar agency wears the edges exposed at the present time. Quarries might have been opened in this rock, as now, for a roofing-slate, had there been quarriers to open them, or houses to roof over; it was in every respect as ancient a looking stone then as in the present late age of the world. There are no sermons that seem stranger or more impressive to one who has acquired just a little of the language in which they are preached, than those which, according to the poet, are to be found in stones; a bit of fractured slate, embedded among a mass of rounded pebbles, proves voluble with ideas of a kind almost too large for the mind of man to grasp. The eternity that hath passed is an ocean without a further shore, and a finite conception may in vain attempt to span it over. But from the beach, strewed with wrecks, on which we stand to contemplate it, we see far out towards the cloudy horizon, many a dim islet and many a pinnacled rock, the sepulchres of successive eras,--the monuments of consecutive creations: the entire prospect is studded over with these landmarks of a hoar antiquity, which, measuring out space from space, constitute the vast whole a province of time; nor can the eye reach to the open, shoreless infinitude beyond, in which only God existed; and, as in a sea-scene in nature, in which headland stretches dim and blue beyond headland, and islet beyond islet, the distance seems not lessened, but increased, by the crowded objects--we borrow a larger, not a smaller idea of the distant eternity, from the vastness of the measured periods that occur between.

The village of Tobermory resembles that of Oban. A quiet bay has its secure island-breakwater in front; a line of tall, well-built houses, not in the least rural in their aspect, but that seem rather as if they had been transported from the centre of some stately city entire and at once, sweeps round its inner inflection, like a bent bow; and an amphitheatre of mingled rock and wood rises behind. With all its beauty, however, there hangs about the village an air of melancholy. Like some of the other western coast villages, it seems not to have grown, piece-meal, as a village ought, but to have been made wholesale, as Frankenstein made his man; and to be ever asking, and never more incessantly than when it is at its quietest, why it should have been made at all? The remains of the Florida, a gallant Spanish ship, lie off its shores, a wreck of the Invincible Armada, "deep whelmed," according to Thompson,

"What time, Snatched sudden by the vengeful blast, The scattered vessels drove, and on blind shelve, And pointed rock that marks th' indented shore, Relentless dashed, where loud the northern main Howls through the fractured Caledonian isles."

Macculloch relates, that there was an attempt made, rather more than a century ago, to weigh up the Florida, which ended in the weighing up of merely a few of her guns, some of them of iron greatly corroded; and that, on scraping them, they became so hot under the hand that they could not be touched, but that they lost this curious property after a few hours' exposure to the air. There have since been repeated instances elsewhere, he adds, of the same phenomenon, and chemistry has lent its solution of the principles on which it occurs; but, in the year 1740, ere the riddle was read, it must have been deemed a thoroughly magical one by the simple islanders of Mull. It would seem as if the guns, heated in the contest with Drake, Hawkins, and Frobisher, had again kindled, under some supernatural influence, with the intense glow of the lost battle.

We weighed anchor about two o'clock, and beat gallantly out the Sound, in the face of an intermittent baffling wind and a heavy swell from the sea. I would fain have approached nearer the precipices of Ardnamurchan, to trace along their inaccessible fronts the strange reticulations of trap figured by Macculloch; but prudence and the skipper forbade our trusting even the docile little Betsey, on one of the most formidable lee shores in Scotland, in winds so light and variable, and with the swell so high. We could hear the deep roar of the surf for miles, and see its undulating strip of white flickering under stack and cliff. The scenery here seems rich in legendary association. At one tack we bore into Bloody Bay, on the Mull coast,--the scene of a naval battle between two island chiefs; at another, we approached, on the mainland, a cave inaccessible save from the sea, long the haunt of a ruthless Highland pirate. Ere we rounded the headland of Ardnamurchan, the slant light of evening was gleaming athwart the green acclivities of Mull, barring them with long horizontal lines of shadow, where the trap terraces rise step beyond step, in the characteristic stair-like arrangement to which the rock owes its name; and the sun set as we were bearing down in one long tack on the Small Isles. We passed the Isle of Muck, with its one low hill; saw the pyramidal mountains of Rum looming tall in the offing; and then, running along the Isle of Eigg, with its colossal Scuir rising between us and the sky, as if it were a piece of Babylonian wall, or of the great wall of China, only vastly larger, set down on the ridge of a mountain, we entered the channel which separates the island from one of its dependencies, Eilean Chaisteil, and cast anchor in the tideway, about fifty yards from the rocks. We were now at home,--the only home which the proprietor of the island permits to the islanders' minister; and, after getting warm and comfortable over the stove and a cup of tea, we did what all sensible men do in their own homes when the night wears late,--got into bed.

We had rich tea this morning. The minister was among his people; and our first evidence of the fact came in the agreeable form of three bottles of fine fresh cream from the shore. Then followed an ample baking of nice oaten cakes. The material out of which the cakes were manufactured had been sent from the minister's store aboard,--for oatmeal in Eigg is rather a scarce commodity in the middle of July; but they had borrowed a crispness and flavor from the island, that the meal, left to its own resources, could scarcely have communicated; and the golden-colored cylinder of fresh butter which accompanied them was all the island's own. There was an ample supply of eggs too, as one not quite a conjuror might have expected from a country bearing such a name,--eggs with the milk in them; and, with cream, butter, oaten cakes, eggs, and tea, all of the best, and with sharp-set sea-air appetites to boot, we fared sumptuously. There is properly no harbor in the island. We lay in a narrow channel, through which, twice every twenty-four hours, the tides sweep powerfully in one direction, and then as powerfully in the direction opposite; and our anchors had a trick of getting foul, and canting stock downwards in the loose sand, which, with pointed rocks all around us, over which the current ran races, seemed a very shrewd sort of trick indeed. But a kedge and halser, stretched thwartwise to a neighboring crag, and jammed fast in a crevice, served in moderate weather to keep us tolerably right. In the severer seasons, however, the kedge is found inadequate, and the minister has to hoist sail and make out for the open sea, as if served with a sudden summons of ejectment.

One of the things that first struck me, as I got on deck this morning, was the extreme whiteness of the sand. I could see it gleaming bright through the transparent green of the sea, three fathoms below our keel, and, in a little flat bay directly opposite, it presented almost the appearance of pulverized chalk. A stronger contrast to the dingy trap-rocks around which it lies could scarce be produced, had contrast for effect's sake been the object. On landing on the exposed shelf to which we had fastened our halser, I found the origin of the sand interestingly exhibited. The hollows of the rock, a rough trachyte, with a surface like that of a steel rasp, were filled with handfuls of broken shells thrown up by the surf from the sea-banks beyond: fragments of echini, bits of the valves of razor-fish, the island cyprina, mactridae, buccinidae, and fractured periwinkles, lay heaped together in vast abundance. In hollow after hollow, as I passed shorewards, I found the fragments more and more comminuted, just as, in passing along the successive vats of a paper-mill, one finds the linen rags more and more disintegrated by the cylinders; and immediately beyond the inner edge of the shelf, which is of considerable extent, lies the flat bay, the ultimate recipient of the whole, filled to the depth of several feet, and to the extent of several hundred yards, with a pure shell-sand, the greater part of which had been thus washed ashore in handfuls, and ground down by the blended agency of the trachyte and the surf. Once formed, however, in this way it began to receive accessions from the exuviae of animals that love such localities,--the deep arenaceous bed and soft sand-beach; and these now form no inconsiderable proportion of the entire mass. I found the deposit thickly inhabited by spatangi, razor-fish, gapers, and large, well-conditioned cockles, which seemed to have no idea whatever that they were living amid the debris of a charnel house. Such has been the origin here of a bed of shell-sand, consisting of many thousand tons, and of which at least eighty per cent. was once associated with animal life. And such, I doubt not, is the history of many a calcareous rock in the later secondary formations. There are strata, not a few, of the Cretaceous and O?litic groups, that would be found--could we but trace their beginnings with a certainty and clearness equal to that with which we can unravel the story of this deposit--to be, like it, elaborations from dead matter, made through the agency of animal secretion.

We set out on our first exploratory ramble in Eigg an hour before noon. The day was bracing and breezy, and a clear sun looked cheerily down on island, and strait, and blue open sea. We rowed southwards in our little boat, through the channel of Eilean Chaisteil, along the trap-rocks of the island, and landed under the two pitchstone veins of Eigg, so generally known among mineralogists, and of which specimens may be found in so many cabinets. They occur in an earthy, greenish-black amygdaloid, which forms a range of sea-cliffs varying in height from thirty to fifty feet, and that, from their sad hue and dull fracture, seem to absorb the light; while the veins themselves, bright and glistening, glitter in the sun, as if they were streams of water traversing the face of the rock. The first impression they imparted, in viewing them from the boat, was, that the inclosing mass was a pitch caldron, rather of the roughest and largest, and much begrimmed by soot, that had cracked to the heat, and that the fluid pitch was forcing its way outwards through the rents. The veins expand and contract, here diminishing to a strip a few inches across, there widening into a comparatively broad belt, some two or three feet over; and, as well described by M'Culloch, we find the inclosed pitchstone changing in color, and assuming a lighter or darker hue, as it nears the edge or recedes from it. In the centre it is of a dull olive green, passing gradually into blue, which in turn deepens into black; and it is exactly at the point of contact with the earthy amygdaloid that the black is most intense, and the fracture of the stone glassiest and brightest. I was lucky enough to detach a specimen, which, though scarce four inches across, exhibits the three colors characteristic of the vein,--its bar of olive green on the one side, of intense black on the other, and of blue, like that of imperfectly fused bottle-glass, in the centre. This curious rock,--so nearly akin in composition and appearance to obsidian,--a mineral which, in its dense form, closely resembles the coarse dark-colored glass of which common bottles are made, and which, in its lighter form, exists as pumice,--constitutes one of the links that connect the trap with the unequivocally volcanic rocks. The one mineral may be seen beside smoking crater, as in the Lipari Isles, passing into pumice; while the other may be converted into a substance almost identical with pumice, by the chemist. "It is stated by the Honorable George Knox, of Dublin," says Mr. Robert Allan, in his valuable mineralogical work, "that the pitchstone of Newry, on being exposed to a high temperature, loses its bitumen and water, and is converted into a light substance in every respect resembling pumice." But of pumice in connection with the pitchstones of Eigg, more anon.

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