Rambles of a Geologist (2)

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CHAPTER III.


I PARTED from Dr Emslie, and walked on along the shore to Portsoy,—for three-fourths of the way over the prevailing grauwacke of the county, and for the remaining fourth over mica schist, primary limestone, hornblende slate, granitic and quartz veins, and the various other kindred rocks of a primary district.  The day was still gloomy and gray, and ill suited to improve homely scenery; nor is this portion of the Banff coast nearly so striking as that which I had travelled over the day before.  It has, however, its spots of a redeeming character,—rocky recesses on the shore; half-beach, half-sward, rich in wild-flowers and shells,—where one could saunter in a calm sunny morning, with one's bairns about one, very delightfully; and the interior is here and there agreeably undulated by diluvial hillocks, that, when the sun falls low in the evening, must chequer the landscape with many a pleasing alternation of light and shadow.  The Burn of Boyne,—which separates, about two miles from Portsoy, a grauwacke from a mica-schist district,—with its bare, open valley, its steep limestone banks, and its gray, melancholy castle, long since roofless and windowless, and surrounded by a few stunted trees, bears a deserted and solitary shagginess about it, that struck me as wildly agreeable.  It is such a valley as one might expect to meet a ghost in, in some still, dewy evening, as gloamin was darkening into uncertainty the outlines of the ancient ruin, and the newly-kindled stars looked down upon the stream.

    It so happened, however, that my only story connected with either ruin or valley was as little a ghost story as might be.  I remember that, when lying ill of fever on one occasion,—indisposed enough to see apparition after apparition flitting across the bed-curtains, like the figures of a magic lanthorn posting along the darkened wall, and yet self-possessed enough to know that they were but mere pictures in the eye, and to watch them as they rose,—I set myself to determine whether they were in any degree amenable to the will, or connected by the ordinary associative links of the metaphysician.  Fixing my mind on a certain object, I strove to call it up in the character, not of an image of the conceptive faculty, but of a fever-vision on the retina.  The image which I pictured to myself was that of a death's head, yellow and grim, and lighted up, as if from within, amid the darkness of a burial vault.  But the death's head obstinately refused to rise.  I had no control, I found, over the fever imagery.  And the picture that rose instead, uncalled and unexpected, was that of a coal-fire burning brightly in a grate, with a huge tea-kettle steaming cheerily over it.

    In traversing the bare height which, rising on the western side of the valley of the Boyne, owes its comparatively bold relief in the landscape to the firmness of the primary rock which composes it, I picked up a piece of graphic granite, bearing its inlaid characters of dark quartz on a ground of cream-coloured feldspar.  This variety, however, though occasionally found in rolled boulders in the neighbourhood of Portsoy, is not the graphic granite for which the locality is famous, and which occurs in a vein in the mica schist of the eminence I was now traversing, about a mile to the east of the town.  The prevailing ground of the granite of the vein is a flesh-coloured feldspar; and the thickly-marked quartzose characters with which it is set, greatly smaller and paler than in the cream-coloured stone, bear less the antique Hebraic look, and would scarce deceive even the most credulous antiquary.  Antiquarians, however, have been sometimes deceived by weathered specimens of this graphic rock, in which the characters were of considerable size, and restricted to thin veins; covering the surface of a schistose groundwork.  Maupertuis, during his famous journey to Lapland, undertaken in 1737, to establish, from actual measurement, that the degrees of latitude are longer towards the pole than at the equator, and which demonstrated, of consequence, the true figure of the earth, travelled thirty leagues out of his way, through a wild country covered with snow, to examine an ancient monument, of which, he says, "the Fins and Laplanders frequently spoke, as containing in its inscription the knowledge of everything of which they were ignorant."  He found it on the side of a mountain, buried in snow; and ascertained, after kindling a great fire around it, in order to lay it bare, that it was a stone of irregular form, composed of various layers of unequal hardness, and that the characters, which were rather more than an inch in length, were written on "a layer of a species of flint," chiefly in two lines, with a few scattered signs beneath, while the rest of the mass was composed of a rock more soft and foliated.  Graphic granite, it may be mentioned, generally occurs, not in masses, but in veins and layers.  The inscription had been described in a previously published dissertation of immense erudition, as Runic; but a Runic scholar of the party found be could make nothing of it.  The philosopher himself was struck by the frequent repetition of characters of nearly the same form on the stone; but he was ingenious enough to get over the difficulty, by remembering that in our notation, after the Arabic manner, characters shaped exactly alike may be very frequently repeated,—nay, as in some of the lines of the Lapland inscription, may succeed each other, as in the sums I. II. III. IIII. or X. XX. XXX.,—and yet very distinct and definite ideas attach to them all.  Still, however, he could not, he says, venture on authoritatively deciding whether the inscription was a work of man or a sport of nature.  He stood between his two conclusions, like our Edinburgh antiquarians between the two fossil Maries of Gueldres; and, richer in eloquence than most of the philosophers his contemporaries, was quite prepared, in his uncertainty, to give gilded mounting and a purple pall to both.

    "Should it be no other than a sport of nature," he concludes, "the reputation which the stone bears in this country deserves that we should have given a description of it.  If, on the other hand, what is on it be an inscription, though it certainly does not possess the beauty of the sculpture of Greece or Rome, it very possibly has the advantage of being the oldest in the universe.  The country in which it is found is inhabited only by a race of men who live like beasts in the forests.  We cannot imagine that they can have ever had any memorable event to transmit to posterity, nor, if ever they had had, that they could have invented the means.  Nor can it be conceived that this country, with its present aspect, ever possessed more civilized inhabitants.  The rigour of the climate and the barrenness of the land have destined it for the retreat of a few miserable wretches, who know no other.  It seems, therefore, that the inscription must have been cut at a period when the country was situated in a different climate, and before some one of those great revolutions which, we cannot doubt, have taken place on our globe.  The position that the earth's axis holds at present with respect to the ecliptic, occasions Lapland to receive the sun's rays very obliquely: it is therefore condemned to a long winter, adverse to man, as well as to all the productions of nature.  No great movement, possibly, in the heavens was necessary, however, to cause all its misfortunes.  These regions may formerly have been those on which the sun shone most favourably; the polar circles may have been what now the tropics are, and the torrid zone have filled the place occupied by the temperate."  Pretty well, Monsieur, for a philosopher!  The various attempts made to unriddle the real history of graphic granite are, however, scarce less curious than the speculations connected with what may be termed its romance.  It seems to be generally held, since the days of old Hutton, who, in his "Theory of the Earth," discussed the subject with his usual ingenuity, that the feldspathic basis of the stone first crystallized, leaving interstices between the crystals, partaking of a certain regularity of form,—a consequence of the regularity of the crystals themselves,—and of a certain irregularity from the eccentric dispositions which these manifest in their position and relations to each other; and that these interstices, being afterwards filled up with quartz, form the characters of the rock,—characters partaking enough of the first element of regularity to present their peculiar graphic appearance, and enough of the second element of irregularity to exhibit forms of an alphabet-like variety of outline.  The chemist, however, in cross-questioning the explanation, has his puzzle to propound regarding it.  Quartz, he says, being considerably less fusible than feldspar, would naturally consolidate first, and so would give form to the more fusible substance, instead of deriving form from it.  On what principle, then, is it that, reversing its ordinary character, it should have been the last of the two substances to consolidate in the graphic granite?—a query to which there seems to be no direct reply, but which as little affects the fact that it was the substance which last consolidated, and which took form from the other, as the decision of the learned Strasburgers, which determined the impossibility oft he long nose in Slawkenbergius's Tale, affected the actual existence of that remarkable feature.  "It happens to be, notwithstanding your objection," said the controversialists on the pro-nose side of the question.  "But it ought not," replied their opponents.

    The rain again returned as I was engaged in examining the graphic granite of the Portsoy vein; the breeze from the sea heightened into a gale, that soon fringed the coast with a broad border of foam; and I entered the town, which looked but indifferently well in its gray dishabille of haze and spray, tolerably wet and worn, with but the prospect before me of being weather-bound for the rest of the day.  I found an old-fashioned inn, kept by somewhat old-fashioned people, who had lately come from the country to "open a public;" and ensconced myself by the fireside, in a huge many-windowed room, that must have witnessed the county dinners of at least a century ago.  Soon wearying, however, of hearing the rain beating mad-like ratans upon the panes, and availing myself of a comparatively "lucid interval," I sallied out, wrapped up in my plaid, to examine the serpentine beds in the neighbourhood, which produce what is so extensively known as the Portsoy marble.  The beds or veins of this substance,—for it is still a moot point whether they occur here as mere insulated masses of contemporary origin with the primary formations which surround them, or as Plutonic dykes injected into fissures at a later period,—are of very considerable extent, one of them measuring about twenty-five yards across, and another considerably more than a quarter of a mile; and, had they but the solidity of the true marbles, they would scarce fail to be regarded as valuable quarries of a highly ornamental stone, admirably suited for the interior decorations of the architect.  But they are unluckily what the quarrier would term rubbly,—traversed by an infinity of cracks and fissures; and it is rare indeed to find a continuous mass out of which a chimney jamb or lintel could be fashioned.  The serpentine was wrought here considerably more than a century and a half ago, and exported to France, for the magnificent Palace of Versailles; which, though regarded by the French nation, says Voltaire, as "a favourite without merit," Louis the Fourteenth persisted at the time in lavishly beautifying, and looked as far abroad as Portsoy for materials with which to adorn it.  I have, however, seen it stated, that the greater part of a ship's cargo, brought afterwards to Paris on speculation, was suffered to lie unwrought for years in the stone-dealer's yard, and was ultimately disposed of as rubbish,—a consequence, probably, of its unfitness, from its shaky texture, for ornamental purposes on a large scale, though for ornaments of the smaller kind, such as boxes, vases, and plates, it has been pronounced unrivalled.  "At Zöblitz, in Upper Saxony," says Professor Jamieson, "several hundred people are employed in quarrying, cutting, turning, and polishing the serpentine which occurs in that neighbourhood; and the various articles into which it is manufactured are carried all over Germany.  The serpentine of Portsoy," he adds, "is, however, far superior to that of Zöblitz, in colour, hardness, and transparency, and, when cut, is very beautiful."

    It is really a pretty stone; and, bad as the evening was, it was by no means one of the worst of evenings for seeing it to advantage in situ, or among the rolled pebbles on the shore.  The varnish-like gloss of the wet imparted to the undressed masses all the effect of polish, and brought out in their proper variegations of colour, every cloud, streak, and vein.  Viewed in the mass, the general hue is green; so much so, that an insulated stack, which stands abreast of one of the beds, a stone-cast in the sea, has greatly the appearance, at a little distance, of an immense mass of verdigris.  But red, gray, and brown are also prevailing colours in the rock: occasional veins and blotches of white give lightness to tile darker portions; and veins of hematitic and deep umbry tints, variety to the portions that are lighter.  The greens vary from the palest olive to the deepest black-green of the mineralogist; the reds and browns, from blood-red to dark chocolate, and from wood-brown to brownish-black; and, thus various in shade, they occur in almost every possible variety of combination and form,—dotted, spotted, clouded, veined,—so that each separate pebble on the shore seems the representative of a rock different from the rocks represented by almost all the others.  Though not much of a mineralogist, I could have spent considerably more time than the weather permitted me to employ this evening, in admiring the beauties of this beach of marbles, or rather,—as the real name, derived from those gorgeous, many-coloured cloudings that impart a terrible splendour to the skins of the snake and viper family, is not only the more correct, but also the more poetical of the two,—this beach of serpentines.  I had, however, to compromise matters between the fierce wind and rain and the pretty rocks and pebbles, by adjourning to the workshop of the Portsoy lapidary, Mr Clark, and examining under cover his polished specimens, of which I purchased for a few shillings a characteristic and elegant little set.  Portsoy is peculiarly rich in minerals; and hence it reckons among its mechanics of the ordinary class, what perhaps no other village in Scotland of the same size and population possesses, a skilful lapidary.  Mr Clark's collection of the graphic granites, serpentines, and talcose and mica schists, of the district, with their associated minerals, such as schorl, talc, asbestos, amianthus, mountain cork, steatite, and schiller spar, will be found eminently worthy a visit by the passing traveller.

    I made several inquiries in the village, though not, as it proved, in the right direction, regarding a poor old lady, several years dead, of whom I had known a very little considerably more than a quarter of a century before, and whose grave I would have visited, bad as the night was, had I met any one who could have pointed it out to me.  But ungrateful Portsoy seemed to have forgotten poor Miss Bond, who, in all her printed letters and little stories, so rarely forgot it.  Have any of my readers ever seen the work (in two slim volumes), "Letters of a Village Governess," published in 1814 by Elizabeth Bond, and dedicated to Sir Walter Scott?  If not, and should they chance to see, as I lately did, a copy on a stall (with uncut leaves, alas! and selling dog cheap), they might possibly do worse things than buy it. [3]

    With better weather I could have spent a day or two very agreeably in Portsoy and its neighbourhood; but the rain dashed unceasingly, and made exploration under the cover of the umbrella somewhat resemble that of a sea-bottom under cover of the diving-bell.  I could see but little at a time, and the little imperfectly.  Miss Bond, in her "Letters," refers, in her light, pleasing style, to what in more favourable circumstances might be seen.  "My troop of light infantry," she says, "keeps me so well employed here during the day, that the silence and repose of the evening is very delightful.  In fine weather I walk by the sea-side, and scramble among the rugged rocks, many of which are inaccessible to human feet, forming a fine retreat for foxes.  These animals often may be seen from the heights, sporting with their cubs in perfect safety.  This day I went to see the works of an old virtuoso, who turns in marble, or rather granite serpentine all kinds of chimney-piece ornaments, rings, ear-rings, &c.  Several specimens of his work, which must have cost him a vast deal of trouble, I thought very beautiful.  It was in this neighbourhood that the celebrated Ferguson spent so much of his time.  The globular stones on the gate of Durn are still to be seen, on which he mapped out the figuring of the terrestrial and celestial globes.  I was told it was forbidden ground to approach the premises of Durn; but I could not resist the temptation of visiting the spot where the young philosopher had shown such early proofs of his genius; and I accordingly paid the forfeit of an impertinent, for the gentleman who resides there caught the prowler, and in genteel terms bade her go about her business, and never return.  How ungracious!  She was doing no harm."

    The morning arose as gloomily as the evening had fallen; and I walked on in the rain to Cullen, fully disposed to sympathize by the way with the "hardy Byron,"—he of the "Narrative,"—who, from his ill-luck in weather, went among his sailors by the name of "Foul-weather Jack."  In the sandy bay of Cullen, where the road, after inflecting inland for some five or six miles, comes again upon the sea, I found the surf charging home in long white lines six waves deep,


Each stepping where his comrade stood,
    The instant that he fell.


The appearance was such as to impart no inadequate idea of the vast attritive power of ocean in wearing down the land.  When pausing for a little abreast of the fishing village, partially sheltered by an old boat, to mark the fierce turmoil, it suddenly occurred to me,—as the tempest weltered around reef and skerry, and roared wildly, mile after mile, along the beach,—that the day and night were now just equal, and that it was the customary equinoctial storm that had broken out to accompany me on my journey.  And so, calculating on a few days more of it, instead of waiting on in the hope of a fair afternoon to examine the outlier of Old Red which occurs in the neighbourhood of Cullen, I was content to see at a distance its mural-sided cliffs rising like broken walls through the flat sand; and, taking the road for Fochabers, with the intention of leaving exploration till fairer weather set in, I resolved on posting straight on, to join my relatives on the opposite side of the Frith.  The deep-red colour of the boulder-clay, as exhibited by the wayside in the water-courses and the water,—for every runnel was tumbling down big and turbid with the rains,—intimated, when, after leaving Cullen some six or seven miles behind me, I passed from a bare moory region of quartz rock into a region of woods and fields, that I was again upon my ancient acquaintance, the Old Red Sandstone.  And the section furnished by the Burn of Tynet showed me shortly after that the intimation was a correct one, and how generally it may be laid down as a rule, that at least the more impalpable portions of the boulder-clay are derived from the rocks on which it rests.  The ichthyolite beds appear in the course of the burn.  They have furnished several good specimens,—among the others, the specimen of Coccosteus figured by Mr Patrick Duff in his "Sketches of the Geology of Moray;" and they are, besides, curious, as being the first to exhibit to the traveller who explores from Gamrie westwards, that peculiar style of colouring which characterizes the Old Red ichthyolites of the shires of Moray and Nairn, and which differs so strikingly from the more sombre style exhibited by the other ichthyolites of Banffshire, with those of Cromarty, Ross, Caithness, and Orkney.  Instead of bearing, like these, one uniform hue, as if deeply shaded with Indian ink, they are gorgeously attired, especially when newly laid open, in white, red, purple, and blue.  The day, however, was ill suited for fishing Pterichthyes and Osteolepi out of the Tynet: the red water was roaring from bank to brae; here eddying along the half-submerged furze,—there tearing down the boulder-clays in raw, red land-slips; and so, casting but one eager glance at the bed where the fish lay, I travelled on, and entered the tall woods to the east of Fochabers.  The rain ceased for a time; and I met in the woods an old pensioner, who had been evidently weather-bound in some public-house, and had now taken the opportunity of the fair interval to stagger to his dwelling.  He was eminently, exuberantly happy,—there could not be two opinions on that head,—full of all manner of bright sunshiny thoughts and imaginations, rendered just a little tremulous and uncertain by the summer-heat exhalations of the imbibed moisture, like distant objects in a hot noonday landscape in July seen through volumes of rising vapour; and a sheep's head and trotters, which he carried under his arm, was, I saw, to serve as a peace-offering to his wife at home.  True, he had been taking a dram, but be was mindful of the family for all that.  He confronted me with the air of an old acquaintance; gave the military salute; and then, laying hold of a corner of my plaid with his thumb and fore-finger,—"I know you," he said,—"I know your kind well; ye're a Highland-Donald.  Od, I've seen ye in the thick o't.  Ye're reugh fellows when ye're bluid's up!"  He had taken me for a grenadier of the 42d; and I lacked the moral courage to undeceive him.  I met nothing further on my way worthy of record, save and except a sheep's trotter, dropped by the old pensioner in one of his zig zaggings to the extreme left; but having no particular use for the trotter at the time and in the circumstances, I left it to benefit the next passer-by.  I finished my journey of eighteen miles in capital style, and was within five minutes' walk of Fochabers when the horn of the mail-guard was sounding up the street.  And, entering the village, I found the vehicle standing opposite the inn door, minus the horses.

    The insides and outsides were sitting down to dinner together as I entered the inn; and I felt, after my long walk, that it would be rather an agreeable matter to join with them.  But in the hope of meeting my old friend Mr Joss, I requested to be shown, not into the passengers' room, but into that of the coachman and guard; and with them I dined.  It so chanced, however, that Mr Joss was not out that day; and the man in the red long coat was a stranger whom I had never seen before.  I inquired of him regarding Mr Joss,—one of perhaps the most remarkable mail-guards in Europe.  I have at least never heard of another who, like him, amuses his leisure on the coach-top with the "Principia" of Newton, and understands it.  And the man, drawing his inference from the interest in Mr Joss which my queries evinced, asked me whether I myself was not a coach-guard.  "No," I rather thoughtlessly replied, "I am not a coach-guard."  Half a minute's consideration, however, led me to doubt whether I had given the right answer.  "I am not sure," I said to myself, on second thoughts, "but the man has cut pretty fairly on the point;—I daresay I am a sort of coach-guard.  I have to mount my twice-a-week coach in all weathers, like any mail-guard among them all; I have to start at the appointed hour, whether the vehicle be empty or full; I have to keep a sharp eye on the opposition coaches; I am responsible, like any other mail-guard, for all the parcels carried, however little I may have had to do with the making of them up; I have always to keep my blunderbuss full charged to the muzzle,—not wishing harm to any one, but bound in duty to let drive at all and sundry who would make war upon the passengers, or attempt running the conveyance off the road; and, finally, as my friend Mr Joss takes the "Principia" to his coach-top, I take pockets full of fossils to the top of mine, and amuse myself in fine days by working out, as I best can, the problems which they furnish.  Yes, I rather think I am a coach-guard."  And so, taking my seat beside my red-coated brother, who had guessed the true nature of my occupation so much more shrewdly than myself, I rode on to Elgin, where I passed the night.

    It is difficult to arrange in the mind the geologic formations of Banffshire in their character as a series of deposits.  The pages of the stony record which the county composes, like those of an unskilfully-folded pamphlet, have been strangely mixed together, so that page last succeeds in some places to page first, and, of the intermediate pages, some appear at the beginning of the work, and some at the end.  It is not until we reach the western confines of the county, some two or three miles short of the river Spey, its terminal boundary in this direction, that we find the beds comparatively little disturbed, and arranged chronologically in their original places.  In the eastern and southern parts of the shire, rocks widely separated by the date of their formation have been set down side by side in patches, occasionally of but inconsiderable extent.  Now the traveller passes over a district of grauwacke, now over a reformation of the Lias; anon he finds himself on a primary limestone,—gneiss, syenite, clay-slate, or quartz-rock; and yet anon amid the fossils of some outlier of the Old Red.  The geological map of the county is, like Joseph's coat of many colours.  I remember seeing, when a boy, more years ago than I am inclined to specify, some workmen engaged in pulling down what had been a house-painter's shop, a full century before.  The painter had been in the somewhat slovenly habit of cleaning his brushes by rubbing them against a hardcast wall, which was covered, in consequence, by a many-coloured layer of paint, a full half-inch in thickness, and as hard as a stone.  Taking a little bit home with me, I polished it by rubbing the upper surface smooth; and, lo! a geological map.  The strata of variously hued pigment, spread originally over the uneven surface of the hard-cast wall, were cut open, by the denudation of the grindstone, into all manner of fantastic forms, and seemed thrown into all sorts of strange neighbourhoods.  The map lacked merely the additional perplexity of a few bold faults, with here and there a decided dike, in order to render it on a small scale a sort of miniature transcript of the geology of Banff; and I have very frequently found my thoughts reverting to it, in connection with deposits of this broken character.  On a rough hard-cast basis of granite I have laid down in imagination, as if by way of priming, coat after coat of the primary rocks,—gneiss, and stratified hornblend, and mica-schist, and quartz-rock, and clay-slate; and then, after breaking the coatings well up, and rubbing them well down, and so spoiling and crumpling up the work as to make their original order considerably a puzzle, I have begun anew to paint over the rough surface with thick coatings of grauwacke and grauwacke-slate.  When this part of the operation was completed, I have again begun to break up and grind down,—here letting a tract of grauwacke sink into the broken primary,—there wearing it off the surface altogether,—yonder elevating the original granitic hard-cast till it rose over all the coatings, Primary and Palæozoic.  And then I have begun to paint yet a third time with a thick Old Red Sandstone pigment; and yet again to break up and wear down,—here to insert a tenon of the Old Red deep into a mortise of the grauwacke, as at Gamrie,—there to dovetail it into the clay-slate, as at Tomantoul,—yonder, after laying it across the upturned quartz-rock, as at Cullen, to rub by much the greater part of it away again, leaving but mere remainder patches and fragments, to mark where it had been.  Lastly, if I had none of the superior Palæozoic or Secondary formations to deal with, I have brushed over the whole, by way of finish, with the variously-derived coatings of the superficial deposits; and thus, as I have said, I have often completed, in idea, after the chance suggestion of the old painter's shop, my portable models of the geology of disturbed districts like the Banffshire one.  The deposits of Moray are greatly less broken.  Denudation has partially worn them down; but they seem to have almost wholly escaped the previous crumpling process.


 
CHAPTER IV.


THE prevailing yellow hue of the Elgin houses strikes the eye of the geologist who has travelled northwards from the Frith of Forth.  He takes leave of a similar stone at Cupar-Fife,—a warmly-tinted yellow sandstone, peculiarly well suited for giving effect to architectural ornament; and after passing along the deep-red sandstone houses of the shires of Angus and Kincardine, and the gneiss, granite, hyperstene, and micaschist houses of Aberdeen and Banff shires, he again finds houses of a deep red on crossing the Spey, and houses of a warm yellow tint on reaching Elgin,—geologically the Cupar-Fife of the north.  And the story that the coloured buildings tell him is, that he has been passing, though by a somewhat circuitous route of a hundred and fifty miles, over an anticlinal geological section,—down in the scale till he reached Aberdeen and had gone a little beyond it, and then up again, until at Elgin he arrives at the same superior yellow bed of Old Red Sandstone which he had quitted at Cupar—Fife.  Both beds contain the same organisms.  The Holoptychius of Dura Den, near Cupar, must have sprung from the same original as the Holoptychins of the Hospital and Bishop-Mill quarries near Elgin; and it seems not improbable that the two beds, thus identical in their character and contents, may have existed, ere the upheaval of the Grampians broke their continuity, as an extended deposit, at the bottom of the same sea.  But with this last and newest of the formations of the Old Red Sandstone the identity of the deposits to the south and north ceases.  The strata which in the south overlie the yellow bed of the Holoptychius represent the Carboniferous period; the overlying strata in the north represent the Oolitic one.  On the one side the miner sinks his shaft, and finds a true coal, composed of the Stigmaria, Calamites, Club-mosses, Ferns, and Araucarians of the Palæozoic era; he sinks his shaft on the other side, and finds but thin seams of an imperfect lignite, composed of the Cycadeæ, Pines, Sphenopteri, and Clathraria of the Secondary period.  The flora which found its subsoil in the Old Red Sandstone north of the Grampians belonged to a scene of things so much more modern than the flora which found its subsoil in the Old Red Sandstone of the south, that all its productions were green and flourishing, waving beside lake, river, and sea, at a time when the productions of the other were locked up, as now, in sand and shale, lime and clay,—the dead mummies of ages long departed.

    Another thoroughly wet morning! varied only from the morning of the preceding day by the absence of wind, and the greater weight of the persevering vertical rain, that leaped upwards in myriads of dancing little pyramids from the surface of every pool.  I walked out under cover of my umbrella, to renew my acquaintance with the outlier of the Weald at Linksfield, and ascertain what sort of section it now presented under the quarrying operations of the lime-burners. There was, however, little to be seen; the bands of green and blue clays, alternating with strata of fossiliferous limestone, and layers of a gray shale thickly charged with minute shells of Cypris, were sadly blurred this morning by the trail of numerous slips from above, which had fallen during the rains, and softened into mud as they rushed downwards athwart the face of the quarry; and the arched band of boulder-clay which so mysteriously underlies the deposit was, save in a few parts, wholly covered up by the debris.  The occurrence of the clay here as an inferior bed, with but the cornstone of the Old Red beneath, and all the beds of the Weald resting over it, forms a riddle somewhat difficult of solution; but it is palpably not reading it aright to regard the deposit, with at least one geologist who has written on the subject, as older than the rocks above.  It is, on the contrary, as a vast amount of various and unequivocal evidence demonstrates, incalculably more modern; nay, we find proof of the fact here in that very bed which has been instanced as rendering it doubtful: the clay of which the interpolation is composed is found to contain fragments, not only of the cornstone on which it rests, but also of the Wealden limestone and shales which it underlies.  It forms the mere filling up of a flat-roofed cavern, or rather of two flat-roofed caverns,—for the limestone roof dipped in the centre to the cornstone floor,—which, previous to the times of the boulder clay, had lain open in what was then, as now, an old-world deposit, charged with long extinct organisms, but which, during the iceberg period, was penetrated and occupied by the clay, as run lime penetrates and occupies the interstices of a dry-stone wall.  It was no day for gathering fossils.  I saw a few ganoid scales, washed by the rain from the investing rubbish, glittering on fragments of the limestone, with a few of the characteristic shells of the deposit, chiefly Unionidæ; but nothing worth bringing away.  The adhesive clay of the Weald, widely scattered by the workmen, and wrought into mortar by the beating rains, made it a matter of some difficulty for the struggling foot to retain the shoe, and, sticking to my soles by pounds at a time, rendered me obnoxious to the old English nickname of "rough-footed Scot."  And so, after traversing the heaps, somewhat like a fly in treacle, had to yield to the rain above and the mud beneath, and to return to do in Elgin what cannot be done equally well in almost any other town of its size in Scotland,—pursue my geological inquiries under cover.

    On this, as on other occasions, I was struck by the complex and very various forms assumed by the ganoid scales of the Wealden.  Throughout the Oolitic system generally, including the Lias, there obtains a singular complexity of type in these little glittering tiles of enamelled bone, which contrasts strongly with the greatly more simple style which obtained among the ganoids of the Palæozoic period.  In many of these last, as in the Coelacanth family, including the genera Holoptychius, Asterolepis, and Glyptolepis, in all their many species, with at least one genus of Dipterians, the genus Dipterus, the external outline and arrangement of scale was as simple as in any of the Cycloid family of the present time.  Like slates on a roof, each single scale covered two, and was covered by two in turn; and the only point of difference which existed in relation to the laying down of these massy slates of bone, and the laying down of the very thin ones of horn which cover fish such as the carp or salmon, was, that in the massier slates, the sides, or cover,—nicely bevelled, in order to preserve an equability of thickness throughout,—were so adjusted, that two scales at their edges, where they lay the one over the other, were not thicker than one scale at its centre.  Even in the other ganoids, their contemporaries, such as the Osteolepis and Diplopterus, where the scales were ranged more in the the fashion, side by side, there was, with much ingenious carpentry in the fitting, a general simplicity of form.  It would almost appear, however, that ere the ganoid order reached the times of the Weald, the simple forms had been exhausted, and that nature, abhorring repetition, and ever stamping upon the scales some specific characteristic of the creature that bore them, was obliged to have recourse to forms of a more complex and involved outline.  These latter-day scales send out nail-like spikes laterally and atop, to lay hold of their neighbours, and exhibit in their under sides grooves that accommodated the nails sent out, in turn, by their neighbours, to lay hold upon them.  Their forms, too, are indescribably various and fantastic.  It seems curious enough, that immediately after this extremely artificial state of things, if I may so speak, the two prevailing orders of the fish of the present day, the Cycloids and Ctenoids, should have been ushered upon the scene, and more than the original simplicity of scale restored.  There took place a sudden reaction, from the fantastic and the complex to the simple and the plain.

    It is further worthy of notice, that though many of the ganoid scales of the Secondary systems, including those of the Wealden, glitter as brightly in burnished enamel as the more splendent scales of the Old Red Sandstone and Coal Measures, there is a curious peculiarity exhibited in the structure of many of the older scales of the highly enamelled class, which, so far as I have yet seen, does not extend beyond the Palæozoic period.  The outer layer of the scale, which lies over a middle layer of a cellular cancellated structure, and corresponds, apparently, with that scarf-skin which in the human subject overlies the rete mucosum, is thickly set over with microscopic pores, funnel-shaped in the transverse section, and which, examined by a good glass, in the horizontal one resemble the puncturings of a sieve.  The Megalichthys of the Coal Measures, with its various carboniferous congeners, with the genera Diplopterus, Dipterus, and Osteolepis of the Old Red Sandstone,—all brilliantly enamelled fish,—are thickly pore-covered.  But whatever purpose these pores may have served, it seems in the Secondary period to have been otherwise accomplished, if, indeed, it continued to exist.  It is a curious circumstance, that in no case do the pores seem to pass through the scale.  Whatever their use, they existed merely as communications between the cells of the middle cancellated layer and the surface.  In a fish of the Chalk,—Macropoma Mantelli,—the exposed fields of the scales are covered over with apparently hollow, elongated cylinders, as the little tubes in a shower-bath cover their round field of tin, save that they lie in a greatly flatter angle than the tubes; but I know not that, like the pores of the Dipterians and the Megalichthys, they communicated between the interior of the scale and its external surface.  Their structure is at any rate palpably different, and they bear no such resemblance to the pores of the human skin as that which the Palæozoic pores present.

    The amount of design exhibited in the scales of some of the more ancient ganoids,—design obvious enough to be clearly read,—is very extraordinary.  A single scale of Holoptychius Noilissimus,—fast locked up in its red sandstone rock,—laid by, as it were, for ever,—will be seen, if we but set ourselves to unravel its texture, to form such an instance of nice adaptation of means to an end as might of itself be sufficient to confound the atheist.  Let me attempt placing one of these scales before the reader, in its character as a flat counter of bone, of a nearly circular form, an inch and a half in diameter, and an eighth-part of an inch in thickness; and then ask him to bethink himself of the various means by which he would impart to it the greatest possible degree of strength.  The human skull consists of two tables of solid bone, an inner and an outer, with a spongy cellular substance interposed between them, termed the diploe; and such is the effect of this arrangement, that the blow which would fracture a continuous wall of bone has its force broken by the spongy intermediate layer, and merely injures the outer table, leaving not unfrequently the inner one, which more especially protects the brain, wholly unharmed.  Now, such also was the arrangement in the scale of the Holoptychius Nobilissimus.  It consisted of its two well-marked tables of solid bone, corresponding in their dermal character, the outer to the cuticle, the inner to the true skin, and the intermediate cellular layer to the rete mucosum; but bearing an unmistakeable analogy also, as a mechanical contrivance, to the two plates and the diploe of the human skull.  To the strengthening principle of the two tables, however, there were two other principles added.  Cromwell, when commissioning for a new helmet, his old one being, as he expresses it, "ill set," ordered his friend to send him a "fluted pot," i.e., a helmet ridged and furrowed on the surface, and suited to break, by its protuberant lines, the force of a blow, so that the vibrations of the stroke would reach the body of the metal deadened and flat.  Now, the outer table of the scale of the Holoptychius was a "fluted pot."  The alternate ridges and furrows which ornamented its surface served a purpose exactly similar with that of the flutes and fillets of Cromwell's helmet.  The inner table was strengthened on a different but not less effective principle.  The human stomach consists of three coats; and two of these, the outermost or peritoneal coat, and the middle or muscular coat, are so arranged, that the fibres of the one cross at nearly right angles those of the other.  The violence which would tear the compact sides of this important organ along the fibres of the outer coat, would be checked by the transverse arrangement of the fibres of the middle coat, and vice versa.  We find the cotton manufacturer weaving some of his stronger fabrics on a similar plan—they also are made to consist of two coats; and what is technically termed the tear of the upper is so disposed that it lies at an angle of forty-five degrees with the tear of the coat which lies underneath.  Now, the inner table of the scale of the Holoptychius—as composed, on this principle, of various layers or coats, arranged the one over the other, so that the fibres of each lay at right angles with the fibres of the others in immediate, contact with it.  In the inner table of one scale I reckon nine of these alternating, variously-disposed layers; so that any application of violence, which, in the language of the lath-splitter, would run lengthwise along the grain of four of them, would be checked by the cross grain in five.  In other words, the line of the tear in five of the layers was ranged at right angles with the line of the tear in four.  There were thus in a single scale, in order to secure the greatest possible amount of strength,—and who can say what other purposes may have been secured besides?—three distinct principles embodied,—the principle of the two tables and diploe of the human skull,—the principle of the variously arranged coats of the human stomach,—and the principle of Oliver Cromwell's "fluted pot."  There have been elaborate treatises written on those ornate flooring-tiles of the classical and middle ages, that are occasionally dug up by the antiquary amid monastic ruins, or on the sites of old Roman stations.  But did any of them ever tell a story half so instructive or so strange as that told by the incalculably more ancient ganoid tiles of the Palæozoic and Secondary periods?

    I called, on my way back from Linksfield, upon my old friend Mr Patrick Duff, and was introduced once more to his exquisite collection, with its unique ichthyolites of at least two genera of fishes of the Old Red,—the Stagonolepis and Placothorax of Agassiz,—which up to the present time are to be seen nowhere else; and various other fine specimens of rare species, which, having sat for their portraits, have their forms preserved in the great work of the naturalist of Neufchatel.  He showed me, with some triumph, one of his later acquisitions,—a fine specimen of Holoptychius from the upper yellow sandstone of Bishop-Mill, which exhibits the dorsal ridge covered with a line of large overlapping scales, not at all unlike those overlapping plates which cover the tail of the lobster; for which, by the way, they were mistaken by the workman who first laid the fossil open.  I examined, too, with some interest, fragments of a gigantic species of Pterichthys, belonging to an inferior division of the same Upper Old Red formation as the yellow stone, designated by Agassiz Pterichthys major, which must have attained to at least thrice the size, linearly, of even its bulkier congeners of the Lower formation of the Coccosteus.  After examining many a drawer, stored, from the deposits of the neighbourhood, with characteristic fossils of the Lias, the Weald, and the Oolite, and of the Upper and Lower Old Red, we set out together to expatiate amid the treasures of the Town Museum.

    Among other recent additions to the Museum, there is an interesting set of the fishes of the Ganges, the donation of a gentleman long resident in India, to which Mr Duff called my attention, as illustrative, in some of the specimens, of the more characteristic ichthyolites of the Old Red Sandstone.  One numerous family, the Pimelodi, abundantly represented in the Gangetic region, in not only the rivers, but also the ponds, tanks, and estuaries of the district, is certainly worthy the careful study of the geologist.  It approaches nearer, in some of its more strongly-marked genera, to the Coccosteus of the Lower Old Red, than any other tribe of existing fishes which I have yet seen.  The body of the Pimelodus, from the anterior dorsal downwards, is as naked as that of the eel; whereas the head, and in several of the species the back, is armed with strong plates of naked bone, curiously fretted, as in many of the ichthyolites of the Lower, and more especially of the Upper Old Red Sandstone, into ridges of confluent tubercles, that radiate from the centre to the edges of the plates.  The dorsal plate, too, when detached, as in many of the species, from the plates of the head, bears upon its inner side a strong central ridge, that deepens as it descends, till it abruptly terminates a little short of the termination of the plate, exactly as in the dorsal plate of Coccosteus, which sunk its central ridge deep into the back of the animal.  The point of resemblance to be mainly noticed, however, is the contrast furnished by the powerful armature of the head and back, with the unprotected nakedness of the posterior portions of the creature—a point specially noticeable in the Coccosteus, and apparent also though in a lesser degree, in some of the other genera of the Old Red, such as the Pterichthyes and Asterolepides.  From the snout of the Coccosteus down to the posterior termination of the dorsal plate, the creature was cased in strong armour, the plates of which remain as freshly preserved in the ancient rocks of the country as those of the Pimelodi of the Ganges on the shelves of the Elgin Museum; but from the pointed termination of the plate immediately over the dorsal fin, to the tail, comprising more than one half the entire length of the animal, all seems to have been exposed, without the protection of even a scale, and there survives in the better specimens only the internal skeleton of the fish and the ray-bones of the fins.  It was armed, like a French dragoon, with a strong helmet and a short cuirass; and so we find its remains in the state in which those of some of the soldiers of Napoleon's old guard, that had been committed unstripped to the earth, may be dug up in the future on the fatal field of Borodino, or along the banks of the Dwina or the Wap.  The cuirass lies still attached to the helmet, but we find only the naked skeleton attached to the cuirass.  The Pterichthys to its strong helmet and cuirass added a posterior armature of comparatively feeble scales, as if, while its upper parts were shielded with plate armour, a lighter covering of ring or scale armour sufficed for the less vital parts beneath.  In the Asterolepis the arrangement was somewhat similar, save that the plated cuirass was wanting: it was a strongly helmed warrior in slight scale armour; for the disproportion between the strength of the plated headpiece and that of the scaly coat was still greater than in the Pterichthys.  The occipital star-covered plates are, in some of the larger specimens, fully three-quarters of an inch in thickness, whereas the thickness of the delicately-fretted scales rarely exceeds a line.

    Why this disproportion between the strength of the armature in different parts of the same fish should have obtained, as in Pterichthys and Asterolepis, or why, while one portion of the animal was strongly armed, another portion should have been left, as in Coccosteus, wholly exposed, cannot of course be determined by the mere geologist.  His rocks present him with but the fact of the disproportion, without accounting for it.  But the natural history of existing fish, in which, as in the Pimelodi, there may be detected a similar peculiarity of armature, may perhaps throw some light on the mystery.  In Hamilton's "Fishes of the Ganges" I find but little reference made to the instincts and habits of the animals described: their deep-river haunts lie, in many cases, beyond the reach of observation; and of the observations actually made, the descriptive naturalist, intent often on mere peculiarities of structure, is not unfrequently too careless.  Hamilton describes the habitats of the various Indian species of Pimelodi, whether brackish estuaries, ponds, or rivers, but not their characteristic instincts.  Of the Silurus, however, a genus of the same great family, I read elsewhere that some of the species, such as the Silurus glanis, being unwieldy in their motions, do not pursue their prey, which consists of small fishes, but lie concealed among the mud, and seize on the chance stragglers that come their way.  And of the Pimelodus gulio, a little, strongly-helmed fish, with a naked body, I was informed by Mr Duff, on the authority of the gentleman who had presented the specimens to the Museum, that it burrowed in the holes of muddy banks, from which it shot out its armed head, and arrested, as they passed, the minute animals on which it preyed.  The animal world is full of such compensatory defences: there is a half-suit of armour given to shield half the body, and a wise instinct to protect the rest.  The Pholas crispata cannot shut its valves so as to protect its anterior parts, without raising them from off those parts which lie behind: like the Irishman in the haunted house, who attempted lengthening his blanket by cutting strips from the top and sewing them on to the bottom, it loses at the one end what it gains at the other; but, hemmed round by the solid walls of the recess which it is its nature to hollow out for itself in shale or stone, the interior parts, though uncovered by the shell, are not exposed.  By closing its valves anteriorly, it shuts the door of its little house, made, like that of the coney-folk of Scripture, in the rock; and then, of the entire cell in which it dwells so secure, what is not shut door is impregnable wall.  The remark of Paley, that the "human animal is the only one which is naked, and the only one which can clothe itself," is by no means quite correct.  One half the hermit crab is as naked as the "human animal," and even less fitted for exposure; for it consists of a thin-skinned, soft, unmuscular bag, filled with delicate viscera; but not even the human animal is more skilful in clothing himself in the spoils of other animals than the hermit crab in wrapping up its naked bag in the strong shell of some dead fusus or buccinum, which it carries about with it in all its peregrinations, as at once clothes, armour, and house.  Nature arms its front, and it is itself wise enough to arm its rear.  Now, it seems not improbable that the half-armed Coccosteus, a heavy fish, indifferently furnished with fins, may have burrowed, like the recent Silurus glanis or Pimelodus gulio, in a thick mud,—of the existence of which in vast quantity, during the times of the Old Red Sandstone, the dark Caithness flagstones, the fetid breccia of Strathpeffer, and the gray stratified clays of Cromarty, Moray, and Banff, unequivocally testify; and that it may have thus not only succeeded in capturing many of its light-winged contemporaries, which it would have vainly pursued in open sea, but may have been enabled also to present to its enemies, when assailed in turn, only its armed portions, and to protect its unarmed parts in its burrow.  It is further worthy of notice, that many of the Pimelodi are furnished with spines, not, like those ichthyodorulites which occur so frequently in the older Secondary and Palæozoic divisions, unfinished in appearance at their lower extremity, as if, like the spines of the ancient Acanthodi, or those of the recent dogfish (Spinax acanthias), they had been simply embedded in the flesh, but bearing, like the wings of the Pterichthys, an articulated aspect.  Those of the Pimelodus rita and Pimelodus gagata are of singular beauty; and when the creatures have no further use for them, and the mud of the Ganges has been consolidated into shale or baked into flagstone around them, they will make very exquisite fossils.  A correct drawing of the plates and spines of some of the members of the Pimelodi family, with a portion of the internal skeletons, arranged in their proper places, but divested of those more destructible parts to which they are attached, would serve admirably to show what strange forms fish not greatly removed from the ordinary type may assume in the fossil state, and might throw some light on the extraordinary appearance assumed, as ichthyolites, by the old family of the Cephalaspians.

    The geological department of the Elgin Museum is not yet very complete.  The private collections of the locality, by forestalling, greatly restrict the supply from the rich deposits in the neighbourhood, and have an unquestioned right to do so.  The Museum contains, however, several interesting organisms.  I saw, among the others, a specimen of Diplopterus, that showed the form and position of the fins of this rather rare ichthyolite much better than any of the Morayshire specimens portrayed by Agassiz in his great work; and beside it, one of the two specimens of Pterichthys oblongus which he figures, and on which he establishes the species.  The other individual,—a Cromarty specimen,—graces my little collection.  The gloomy day passed pleasantly in deciphering, with so accomplished a geologist as Mr Duff, these curious hieroglyphics of the old world, that tell such wonderful stories, and in comparing viva voce, as we were wont to do long years before in lengthy epistles, our respective notions regarding the true key for laying open their more occult meanings.  And, after sharing with him in his family dinner, I again took my seat on the mail, as a chill, raw evening was falling, and rode on, some six or eight and twenty miles, to Campbelton.  The rain pattered drearily through the night on my bed-room window; and as frequent exposure to the wet had begun to tell on a constitution not altogether so strong as it had once been, I awakened oftener than was quite comfortable, to hear it.  The morning, however, was dry, though gray and sunless; and, taking an early breakfast at the inn, I traversed the flat gravelly points of Ardersier and Fortrose, that, projecting like moles far into the Frith, narrow the intervening ferry to considerably less than one-third the width which it would present were they away.  The origin of these long detrital promontories, which form, when viewed from the heights on either side, so peculiar a feature in the landscape, and which, were they directly opposite, instead of being set down a mile awry, would shut up the opening altogether, has not yet been satisfactorily accounted for.  One special theory assigns their formation to the agency of the descending tide, striking in zig-gig style, in consequence of some peculiarity of the coastline or of the bottom, from side to side of the Frith, and depositing a long trail of sand and gravel, at nearly right angles with the beach, first on the one shore and then on the other.  But why the tide, which runs in various zig-zag crossings in the course of the Frith, should have the effect here; and nowhere else, of raising two vast mounds, each a full mile and a quarter in length, with an average breadth of from two to five furlongs, is by no means very apparent.  Certainly the present tides of the Frith could not have formed them, nor could they have been elevated to their present average height of ten or twelve feet over the flood-line in a sea standing at the existing level.  If they in reality originated in this cause, it must have been ere the latter upheavals of the land or recessions of the sea, when the great Caledonian Valley existed as a narrow ocean sound, swept by powerful currents. Upon another and entirely different hypothesis, these flat promontories have been regarded as the remains, levelled by the waves, and gapped direct in the middle by the tide, of a vast transverse morain of the great valley, belonging to the same glacial age as the lateral morains some ten or fifteen miles higher up, that extend from the immediate neighbourhood of Inverness to the mansion-house of Dochfour.  But this hypothesis, like the other, is not without its difficulties.  Why, for instance, should the promontories be a mile awry?  There is, however, yet another mode of accounting for their formation, which I am not in the least disposed to criticise.

    They were constructed, says tradition, through the agency of the arch-wizard Michael Scott.  Michael had called up the hosts of Faery to erect the cathedral of Elgin and the chanonry kirk of Fortrose, which they completed from foundation to ridge, each in a single night,—committing, in their hurry, merely the slight mistake of locating the building intended for Elgin in Fortrose, and that intended for Fortrose in Elgin; but, their work over and done, and when the magician had no further use for them, they absolutely refused to be laid; and, like a posse of Irish labourers thrown out of a job, came thronging round him, clamouring for more employment.  Fearing lest he should be torn in pieces,—a catastrophe which has not unfrequently happened in such circumstances in the olden time, and of which those recent philanthropists who engage themselves in finding work for the unemployed may have perhaps entertained some little dread in our own days,—he got rid of them for the time by setting them off in a body to run a mound across the Moray Frith from Fortrose to Ardersier.  Toiling hard in the evening of a moonlight night, they had proceeded greatly more than two-thirds towards the completion of the undertaking, when a luckless Highlander passing by bade God-speed the work, and, by thus breaking the charm, arrested at once and for ever the construction of the mound, and saved the navigation of Inverness.

    I stood for a few seconds at the Burn of Rosemarkie, undecided whether I should take the Scarfs-Craig road,—a breakneck path which runs eastwards along the cliffs, and which, though the rougher, is the more direct Cromarty line of the two,—or the considerably better though longer line of the White Bog, which strikes upwards along the burn in a westerly direction, and joins the Cromarty and Inverness highway on the moor of the Maolbuie.  I had got into a part of the country where every little locality, and every more striking feature in the landscape, has its associated tradition; and the pause of a few moments at the two roads recalled to my memory the details of a ghost-story, long regarded in the district in which it was best known as one of the most authentic of its class, but which seems by no means inexplicable on natural principles. [4]


 
CHAPTER V.


ROSEMARKIE, with its long narrow valley and its red abrupt scaurs, [5] is chiefly interesting to the geologist for its vast beds of the boulder-clay.  I am acquainted with no other locality in the kingdom where this deposit is hollowed into ravines so profound, or presents precipices so imposing and lofty.  The clay lies thickly over most part of the Black Isle and the peninsula of Easter Ross,—both soft sandstone districts,—bearing everywhere an obvious relation, as a deposit, to both the form and the conditions of exposure of the existing land,—just as the accumulated snow of a long lying snow-storm, exposed to the drifting wind, bears relation to the heights and hollows of the tracts which it covers.  On the higher eminences the clay forms a comparatively thin stratum, and in not a few instances it has been wholly worn away; while on the lower grounds, immediately over the old coast line, and in the sides of hollow valleys,—exactly such places as we might expect to see the snow occupying most deeply after a night of drift,—we find it accumulated in vast beds of from eighty to an hundred feet in thickness.  One of these occurs in the opening of the narrow valley along which my course this morning lay, and is known far and wide,—for it forms a marked feature in the landscape, and harbours in its recesses a countless multitude of jackdaws,—as the "Kaes' Craig of Rosemarkie."  It presents the appearance of a hill that had been cut sheer through the middle from top to base, and exhibits in its abrupt front a broad red perpendicular section of at least a hundred feet in height, barred transversely by thin layers of sand, and scored vertically by the slow action of the rains.  Originally it must have stretched its vanished limb across the opening, like some huge snow-wreath accumulated athwart a frozen rivulet; but the incessant sweep of the stream that runs through the valley has long since amputated and carried it away; and so only half the hill now remains.  The Keas' Craig resembles in form a lofty chalk cliff, square, massy, abrupt, with no sloping fillet of vegetation bound across its brow, but precipitous direct from the hill-top.  The little ancient village of Rosemarkie stretches away from its base on the opposite side of the stream; and on its summit, and along its sides, groups of chattering jackdaws, each one of them as reflective and philosophic as the individual immortalized by Cowper, look down high over the chimneys into the streets.  The clay presents here, more than in almost any other locality with which I am acquainted, the character of a stratified deposit; and the numerous bands of sand by which the cliff is horizontally streaked from top to bottom we find hollowed, as we approach, into a multitude of circular openings, like shot-holes in an old tower, which form breeding places for the daw and the sand-martin.  The biped inhabitants of the cliff are greatly more numerous than the biped inhabitants of the quiet little hamlet below; and on Fortrose fair-days, when, in virtue of an old feud, the Rosemarkie boys were wont to engage in formidable bickers with the boys of Cromarty, I remember, as one of the invading belligerents, that, in bandying names with them in the fray, we delighted to bestow upon them, as their hereditary sobriquet, given of course, in allusion to their feathered neighbours, the designation of the "Rosemarkie kaes."  Cromarty, however, is two-thirds surrounded by the waters of a frith abounding in seafowl; and the little fellows of Rosemarkie, indignant at being classed with their kaes, used to designate us with hearty emphasis, in turn, as the "Cromarty cooties," i.e. coots.

    A little higher up the valley, on the western side, there occurs in the clay what may be termed a group of excavations, composing a piece of scenery ruinously broken and dreary, and that bears a specific character of its own which scarce any other deposit could have exhibited.  The excavations are of considerable depth and extent,—hollows out of which the materials of pyramids might have been taken.  The precipitous sides are fretted by jutting ridges and receding inflections, that present in abundance their diversified alternations of light and shadow.  The steep descents form cycloid curves, that flatten at their bases, and over which the ferruginous stratum of mould atop projects like a cornice.  Between neighbouring excavations there stand up dividing walls, tall and thin as those of our city buildings, and in some cases broken at their upper edges into rows of sharp pinnacles or inaccessible turf-coped turrets; while at the bottom of the hollows, washed by the runnels which, in the slow lapse of years, have been the architects of the whole, we find cairn-like accumulations of water-rolled stones,—the disengaged pebbles and boulders of the deposit.  The boulders and pebbles project also from the steep sides, at all heights and of all sizes, like the primary masses inclosed in our ancient conglomerates, when exhibited in wave-worn precipices,—forcing upon the mind the conclusion that the boulder-clay is itself but an unconsolidated conglomerate of the later periods, which occupies nearly the same relative position to the existing vegetable mould, with all its recent productions, that the great conglomerate of the Old Red Sandstone occupies in relation to the lower ichthyolite beds of that system, with their numerous extinct organisms.  But its buried stones are fretted with hieroglyphic inscriptions, in the form of strange scratchings and polishings, grooves, ridges, and furrows,—always associated with the boulder-clays,—which those of the more ancient conglomerates want, and which, though difficult to read, seem at length to be yielding up the story which they record.  Of this, however, more anon.  Viewed by moonlight, when the pale red of the clay where the beam falls direct is relieved by the intense shadows, these excavations of the valley of Rosamarkie form scenes of strange and ghostly wildness: the projecting, buttress-like angles,—the broken walls,—the curved inflections,—the pointed pinnacles,—the turrets, with their masses of projecting coping,—the utter lack of vegetation, save where the heath and the furze rustle far above,—all combine to form assemblages of dreary ruins, amid which, in the solitude of night, one almost expects to see spirits walk.  These excavations have been designated from time immemorial, by the neighbouring town's-people, as "the Danes;" but whether the name be, as is most probable, merely a corruption of an appropriate enough Saxon word, "the dens," or derived, as a vague tradition is said to testify, from the ages of Danish invasion, it is not quite the part of the geologist to determine.  It may be worth mentioning, however, from its bearing on the point, that there are two excavations in the boulder-clay near Cromarty, one of which has been long known by the name of "the Morial's Den;" while the other, greatly smaller in size, rejoices in the double diminutive of "the Little Dennie."  For an hour or so the Danes proved agreeable though somewhat silent companions; and then, climbing the opposite side of the valley, I gained the high road, and, walking on to Cromarty, found myself once more among "the old familiar faces."

    In a few days the storm blew by; and as the prolonged rains had cleared out the deep ravines of the district, and given to the boulder-clay in which they are scooped a freshness in its section analogous to fresh fracture in rocks of harder consistency, I availed myself of the facilities afforded me in consequence, for exploring it once more.  It has long constituted one of the hardest of the many riddles with which our Scottish deposits exercise the patience and ingenuity of the geologist.  I remember a time when, after passing a day under its barren scaurs, or hid in its precipitous ravines, I used to feel in the evening as if I had been travelling under the cloud of night, and had seen nothing.  It was a morose and taciturn companion, and had no speculation in it.  I might stand in front of its curved precipices, red, yellow, or gray, according to the prevailing average colour of the rocks on which it rests, and mark their water-rolled boulders, of all qualities and sizes, sticking out in bold relief from the surface, like the rock-like protuberances that roughen the rustic basements of the architect, from the line of the wall; but I had no open sesame to form vistas through them into the recesses of the past.  I saw merely the stiff pasty matrix of which they are composed, and the inclosed pebbles.  But the boulder-clay has of late become more sociable; and, though with much hesitancy and irresolution, like old Mr Spectator on the first formal opening of his mouth,—a consequence, doubtless, in both cases of previous habits of silence long indulged,—it begins to tell its story.  And a most curious story it is.

    The morning was clear, but just a little chill; and a soft covering of snow, that had fallen during the storm on the flat summit of Benwevis, and showed its extreme tenuity by the paleness of its tint of watery blue, was still distinctly visible at the distance of full twenty miles.  The sun, low in the sky,—for the hour was early,—cast its slant rays athwart the prospect, giving to each nearer bank and hillock, and to the more distant protuberances on the mountain-sides, those well-defined accompaniments of shadow that serve, by throwing the minor features of a landscape upon the eye in bold relief, to impart to it an air of higher finish and more careful filling up than it ever bears under a more vertical light.  I took the road which, leading westward from the town towards Invergordon Ferry, skirts the Frith on the one hand, and runs immediately under the noble escarpment of green bank formed by the old coast line on the other.  Fully two-thirds of the entire height of the rampart here, which rises in all about a hundred feet over the sea-level, is formed of the boulder-clay; and I am acquainted with no locality in which the deposit presents more strongly, for at least the first half mile, one of its marked scenic peculiarities.  It is furrowed vertically on the slope, as if by enormous flutings in the more antique Doric style; and the ridges by which these are separated,—each from a hundred to a hundred and fifty feet in length, and from five-and-twenty to thirty feet in average height;—resemble those burial mounds with which the sexton frets the churchyard turf; with this difference, however, that they seem the burial mounds of giants, tall and bulky as those that of old warred against the gods.  They are striking enough to have caught the eye of the children of the place, and are known among them as the Giants' Graves.  I could fain have taken their portrait in a calotype this morning, as they lay against the green bank,—their feet to the shore, and their heads on the top of the escarpment,—like patients on a reclining bed, and strongly marked, each by its broad bar of yellow light and of dark shadow, like the ebon and ivory buttresses of the poet.  This little vignette, I would have said to the landscape-painter, represents the boulder-clay, after its precipitous banks—worn down, by the frosts and rains of centuries, into parallel runnels, that gradually widened into these hollow grooves—had sunk into the angle of inclination at which the disintegrating agents ceased to operate, and the green sward covered all up.  You must be studying these peculiarities of aspect more than ever you studied them before.  There is a time coming when the connoisseur will as rigidly demand the specific character of the various geologic rocks and deposits in your hills, scaurs, and precipices, as he now demands specific character in your shrubs and trees.

    It is worthy the notice of the young geologist, who has just set himself to study the various effects produced on the surface of a country by the deposits which lie under it, that for about a quarter of a mile or so, the base of the escarpment here is bordered by a line of bogs, that bear in the driest weather their mantling of green.  They are fed with a perennial supply of water, by a range of deep-seated springs, that come bursting out from under the boulder-clay; and one of their number, which bears, I know not why, the name of Samuel's Well, and yields its equable flow at an equable temperature, summer and winter, into a stone trough by the wayside, is not a little prized by the town's-people, and the seamen that cast anchor in the opposite roadstead, for the lightness and purity of its water.  What is specially worthy of notice in the case is, the very definite beginning and ending of the chain of bogs.  All is dry at the base of the escarpment, up to the point at which they commence; and then all is equally dry at the point at which they terminate.  And of exactly the same extent,—beginning where the bogs begin, and ending where they end,—we may trace an ancient stratum of pure sand, of considerable thickness, intercalated between the base of the clay and the superior surface of the Old Red Sandstone.  It is through this permeable sand that the profoundly seated springs find their way to the surface,—for the clay is impermeable; and where it comes in contact with the rock on either side of the arenaceous stratum, the bogs cease.  The chain of green bogs is a consequence of the stratum of permeable sand.  I have in vain sought this ancient layer of sand,—decidedly of the same era with the argillaceous bed which overlies it,—for aught organic.  A single shell, so unequivocally of the period of the boulder-clay as to occur at the base of the deposit, would be worth, I have said, whole drawerfuls of fossils furnished by the better-known deposits.  But I have since seen in abundance shells of the boulder-clay.

    There is another scenic peculiarity of the clay, which the neighbourhood of Cromarty finely illustrates, and of which my walk this morning furnished numerous striking instances.  The Giants' Graves—to borrow from the children of the place—occur on the steep slopes of the old coast line, or in the sides of ravines, where the clay, as I have said, had once presented a precipitous front, but had been gradually moulded, under the attritive influences of the elements, into series of alternating ridges and furrows, which, when they had flattened into the proper angle, the green sward covered up from further waste.  But the deep dells and narrow ravines in which many ranges of these graves occur are themselves peculiarities of the deposit.  Wherever the boulder-clay lies thick and continuous, as in the parish of Cromarty, on a sloping table-land, every minute streamlet cuts its way to the solid rock at the bottom, and runs through a deep dell, either softened into beauty by the disintegrating process, or with all its precipices standing up raw and abrupt over the stream.  Four of these ravines, known as the "Old Chapel Burn," the "Ladies' Walk," the "Morial's Den," and the "Red Burn," each of them cutting the escarpment of the ancient coast line from top to base, and winding far into the interior, occur in little more than a mile's space; and they lie still more thickly farther to the west.  These dells of the boulder-clay, in their lower windings,—for they become shallower and tamer as they ascend, till they terminate in the uplands in mere drains, such as a ditcher might excavate at the rate of a shilling or two per yard,—are eminently picturesque.  On those gentler slopes where the vegetable mould has had time and space to accumulate, we find not a few of the finest and tallest trees of the district.  There is a bosky luxuriance in their more sheltered hollows, well known to the schoolboy what time the fern begins to pale its fronds, for their store of hips, sloes, and brambles; and red over the foliage we may see, ever and anon as we wend upwards, the abrupt frontage of some precipitous scaur, suited to remind the geologist, from its square form and flat breadth of surface, of the cliffs of the chalk.  When viewed from the sea, at the distance of a few miles, these ravines seem to divide the sloping tracts in which they occur into large irregular fields, laid out considerably more in accordance with the principles of the landscape gardener than the stiffly squared rectilinear fields of the agriculturist.  They are ha-has of Nature's digging; and their bottom and sides in this part of the country we still find occupied in a few cases—though in many more they have been ravaged by the wasteful axe—by noble forest-hedges, tall enough to overtop, in at least their middle reaches, the tracts of table-land which they divide.

    I passed, a little farther on, the quarry of Old Red Sandstone, with a huge bank of boulder-clay resting over it, in which I first experienced the evils of hard labour, and first set myself to lessen their weight by becoming an observer of geological phenomena.  It had been deserted apparently for many years; and the debris of the clay partially covered up, in a sloping talus, the frontage of rock beneath.  Old Red Sandstone and boulder-clay, a broad bar of each!—such was the compound problem which the excavation propounded to me when I first plied the tool in it,—a problem equally dark at the time in both its parts.  I have since got on a very little way with the Old Red portion of the task; but alas for the boulder-clay portion of it!  A bar of impenetrable shadow has rested long and obstinately over the newer deposit; and I scarce know whether the light which is at length beginning to play on its pebbly front be that of the sun or of a delusive meteor.  But courage, patient hearts! the boulder clay will one day yield up its secret too.  Still further on by a few hundred yards, I could have again found use for the calotype, in transferring to paper the likeness of a protuberant picturesque cliff, which, like the Giants' Graves, could have belonged, of all our Scotch deposits, to only the boulder clay.  It stands out, on the steep acclivity of a furze-covered bank, abrupt as a precipice of solid rock, and yet seamed by the rain into numerous divergent channels, with pyramidal peaks between; and, combining the perpendicularity of a true cliff with the water-scooped furrows of a yielding clay, it presents a peculiarity of aspect which strikes, by its grotesqueness, eyes little accustomed to detect the picturesque in landscape.  I remember standing to gaze upon it when a mere child; and the fisher children of the neighbouring town still tell that "it has been prophesied" it will one day fall, "and kill a man and a horse on the road below,"—a legend which shows it must have attracted their notice too.

    I selected as the special scene of exploration this morning, a deep ravine of the boulder-clay, which had been recently deepened still more by the waters of a mill-pond, that had burst during a thunder-shower, and, after scooping out for themselves a bed in the clay some twelve or fifteen feet deep, where there had been formerly merely a shallow drain, had then tumbled into the ravine, and bared it to rock.  The sandstones of the district, soft and not very durable, show the scratched and polished surfaces but indifferently well, and, when exposed to the weather, soon lose them; but in the bottom of the runnel by which the ravine is swept I found them exceedingly well marked,—the polish as decided as the soft red stone could receive, and the lines of scratching running in their general bearing due east and west, at nearly right angles with the course of the stream.  Wherever the rock had been laid bare during the last few months, there were the markings; wherever it had been laid bare for a few twelvemonths, they were gone.  I next marked a circumstance which has now for several years been attracting my attention, and which I have found an invariable characteristic of the true boulder-clay.  Not only do the rocks on which the deposit rests bear the scratched and polished surfaces, but in every instance the fragments of stone which it incloses bear the scratchings also, if from their character capable of receiving and retaining such markings, and neither of too coarse a grain nor of too hard a quality.  If of limestone, or of a coherent shale, or of a close, finely-grained sandstone, or of a yielding trap, they are scratched and polished,—invariably on one, most commonly on both their sides; and it is a noticeable circumstance, that the lines of the scratchings occur, in at least nine cases out of every ten, in the lines of their longer axes.  When decidedly oblong or spindle-shaped, the scratchings run lengthwise, preserving in most cases, on the under and upper sides, when both surfaces are scratched, a parallelism singularly exact; whereas, when of a broader form, so that the length and breadth nearly approximate, though the lines generally find out the longer axis, and run in that direction,—they are less exact in their parallelism, and are occasionally traversed by cross furrows.  Of such certain occurrence is this longitudinal lining on the softer and finer-grained pebbles of the boulder-clay, that I have come to regard it as that special characteristic of the deposit on which I can most surely rely for purposes of identification.  I am never quite certain of the boulder-clay when I do not detect it, nor doubtful of the true character of the deposit when I do.  When examining, for instance, the accumulation of broken Liasic materials in the neighbourhood of Banff I made it my first care to ascertain whether the bank inclosed fragments of stone or shale bearing the longitudinual markings; and felt satisfied, on finding that it did, that I had discovered the period of its re-formation.



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NOTES.

 
3.    A description of Miss Bond and of her " Letters," here referred to, is given in the fifth chapter of "My Schools and Schoolmasters."
 
4.    The story here referred to is narrated in "Scenes and Legends of the North of Scotland," chap.
XXV.
 
5.    Scaur, Scotice, a precipice of clay.  There is no single English word that conveys exactly the same idea.

 


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