IN the level steppes of Russia, where the traveller may journey without seeing a hill for weeks together, the rocks have their grooved and polished surfaces. And even in localities where there are hills, the hills not unfrequently merely add to the difficulty. The lofty top of Schehallion, for instance, is grooved and polished; and, pray, from what neighbouring eminence could the glacier have descended on it? Extreme, however, as the difficulties that environ the phenomena may seem, they have been manfully met by Agassiz, and dealt with in a style in which only a man of genius could have dealt with anything. And if difficulties still attend his theory, there are at least other difficulties which it ingeniously obviates; and it seems but right, at all events, to give it generous entertainment and a fair trial, until such time as it may be found untenable, or until at least something better turns up to set in its place.

The flat steppes of Russia have, I have said, their groovings and polishings: they have also their moraine; and so enormous is the extent of the latter, that for week after week the traveller may find it stretching through the central wilds of the empire, on and on without apparent termination, by North Novogorod towards Pinsk, as far as the confines of Silesia. It exists as a broad belt of erratic blocks, mingled with heaps of gravel, and resembles, from its linear continuity, the scattered remains of some such vast wall as that which protected of old the Chinese frontier from the Tartar. And here, says Agassiz, is the moraine of a glacier that had for its centre no group of local eminences, no vanished Alps of the Frozen Ocean, but the North Pole itself. The ice of the Southern Pole advances as far. Could we but reverse the conditions of the two poles, the northern [266] icy barrier would extend to the English Channel, and the whole British islands would lie enveloped in one vast glacial winding-sheet, that, overlying the summits of our hills, would furrow with its parallel striæ even the granitic top of Schehallion.

A complete reversal of the conditions of the two poles would account, doubtless, for many of the phenomena existing in connexion with the boulder-clay, which seem otherwise so inexplicable. But is the reversal itself possible? A Laplace or Lagrange could perhaps answer the question. This much, however, men of lower attainments may know: that the meteorological condition of the two poles are very different, — the icy barrier advancing, in the case of the one, many degrees nearer the equator than it does in the case of the other; that their astronomical condition is also very different, the sun being many millions of miles nearer the one in winter, and nearer the other in summer. It may be known, further, that these astronomical conditions are in a state of gradual change; that, so far at least as human observation extends, the change has been steadily progressing in one direction; that should it but continue, a time must inevitably arrive when their astronomical circumstances shall be wholly reversed, — a time when the sun shall look down upon our northern hemisphere in aphelion in winter, and in perihelion in summer. True, we do not yet know that the meteorological differences of the poles depend on their astronomical differences, or whether the gradual diminution in the eccentricity of the earth's orbit, which has been lessening these latter differences ever since astronomers registered their observations, may not be like the change in the ecliptic, — the result of a mere oscillation, limited to a few degrees.

Let us, however, conclude the case to be otherwise: let us deem the oscillations in the earth's orbit to be so great as to involve an alternate progress in the sun, between his two [267] foci; let us further infer a dependence between his place in each and the meteorological condition of the poles. We stand, let us suppose, on the summit of a hill; but, as if an immense wedge had been thrust between our feet and the soil, we rise to a higher elevation on an inclined plane of ice, and look over a frozen continent, enlivened by no winding arms of the sea, and bounded by no shore. In the words of Coleridge, —

'The ice is here; the ice is there;
The ice is all around;
It cracks and growls, and roars and howls,
A wild and ceaseless sound.'
It is summer; and the sun, in perihelion, looks down with intense glare on the rugged surface. There is a ceaseless dash of streams that come leaping from the more exposed ridges, as they shrink and lessen in the heat, or patter from the sunlit pinnacles, like rain from the eaves of a roof in a thunder-shower. They disappear in cracks and fissures and we may hear the sound, rising from where they break themselves, far beneath, in chill caverns and gloomy recesses, where, even at this season, at noon the temperature rises but little above the freezing-point, and sinks far beneath it every evening as the sun declines. The night shall scarce have come on when all these water-courses shall be bound up by the frost, and the melted accumulations which they precipitated into the fissures beneath shall be converted into expansive wedges of ice, under the influence of which the whole ice-continent shall be moving slowly onwards over the buried land. Millions of millions of wedges shall ply their work during the night on every square mile of surface, and the coming day shall prepare its millions of millions more. There is thus a slow but steady motion induced towards the open space where the huge glacier terminates the rocks far below grind down into a clayey paste, as the ponderous mass goes crushing over them , — deliberate, when [268] at its quickest, as the hour-hand of a timepiece; and vast fragments are borne away from submerged peaks and precipices by the enclasping solid, just as ordinary streams bear along their fragments of rock and stone from the banks and ridges that lie most exposed to the sweep of their currents. All around, according to Milton,
'A frozen continent
Lies dark and wild, beat by perpetual storms.'
Not a peak of our higher hills appears: all are enveloped in their cerements of cold and death. Even along the flanks of the gigantic Alps, the groovings and polishings rise, says Agassiz, to an elevation of nine thousand feet; and then, and not before, do we find the pinnacles that overlooked the scene standing up sharp and unworn. If we ask a varied prospect, we must remove from our present stand, to where Mont Blanc and his compeers raise their white summits over the line of the horizon, to give earnest of a buried continent, or to where the smoke and fire of Hecla ascends amid the level from a dripping crater of ice.


CROMARTY, — my own especial manor, which I have so often beat over, but not yet half exhausted, — presents to the geologist one of the most interesting centres of exploration in Scotland. Does he wish thoroughly to study our Scotch Lias, Upper and Lower, with the Oolitic member which immediately overlies it? — then let him remove to Cromarty, and study it there. Is he solicitous to acquaint himself with the fossils of the Lower1 Old Red Sandstone in that state of finest preservation in which the microscope finds most of beauty and finish in them? — then let him by all


1 Now ascertained to be Middle.

[269] means settle at Cromarty. Is he wishful of knowing much about the last elevated of our granite hill-ranges, — a range newer apparently than many of our south-country traps ? — let him not hesitate to take lodgings at Cromarty. Is he curious regarding our boulder-clay ? — let him set himself carefully to examine the splendid sections which it presents in the neighbourhood of Cromarty. Does he feel aught of interest in our raised beaches? — then let him come and live upon one at Cromarty. Is he desirous of furnishing himself with a key to the geology of the north of Scotland generally? — in no place will he be able to possess himself of so complete a key as among the upturned strata of Cromarty. Had he to grope his way along a course of discovery, he might find the district yielding up its more interesting phenomena but slowly: to know its Lias deposits thoroughly would be a work of months, and to know its Old Red Sandstone, a work of years; but with some intelligent guide to point out to him the localities to which his attention should be directed, and all in them that has been done and observed already, he would find that much might be accomplished in the course of a single week, — especially in the long calm days of July, when the more exposed shores of the district, with all their insulated stacks and ledges, and all their deep-sea caves, may be explored by boat.


WE swept downwards through the noble opening of the Cromarty Firth, and landed under the southern Sutor, on a piece of a rocky beach, overhung by a gloomy semicircular range of precipices. The terminal points of the range stand so far out into the sea, as to render inaccessible, save by boat, or at the fall of ebb in stream tides, the piece of crescent-shaped beach within. Each of the two promontories [270] is occupied by a cave in which the sea at flood stands some ten or twelve feet over the gravel bottom, and there are three other caves in the semicircle, into which the tide has not entered since it fell back from the old coast line. The larger and deeper of the three caves in the semicircular inflection is mainly that which we had landed to explore. It runs a hundred and fifty feet into the granitic rock, in the line of a fault that seems first to have opened some eight or ten feet, and then, leaning back, to have closed its sides atop, forming in this way a long angular hollow. It has borne for centuries the name of the Doocot (i.e., Dove-cot) cave; and has been from time immemorial a haunt of pigeons. We approach the opening: there is a rank vegetation springing up in front, where the precipice beetles over, and a small stream comes pattering in detached drops like those of a thunder-shower; and we see luxuriating under it, in vast abundance, the hot, bitter, fleshy-leaved scurvy-grass, of which Cook made such large use, in his voyages, as an anti-scorbutic. The floor is damp and mouldy; the green ropy sides, which rise some five-and-twenty feet ere they close, are thickly furrowed by ridges of stalactites, that become purer and whiter as we retire from the light and the vegetative influences, and pre sent in the deeper recesses of the cave the hue of statuary marble. The last vegetable that appears is a minute delicate moss, about half an inch in length, which slants outwards to the light on the prominences of the sides, and overlies myriads of similar sprigs of moss, long since converted into stone, but which, faithful in death to the ruling law of their lives, still point, like the others, to the free air and sunshine. As we step onwards, we exchange the brightness of noon for the mellower light of evening. A few steps further, and evening has deepened into twilight. We still advance; and twilight gives place to a gloom dusky as that of midnight. We grope on, till the rock closes before us; and, turning round, see the blue waves of the [271] firth through the long, dark vista, as if we viewed them through the tube of some immense telescope. We strike a light. The roof and sides are crusted with white stalactites, that depend from the one like icicles from the eaves of a roof in a severe frost, and stand out from the other in pure, semi-transparent ridges, that resemble the folds of a piece of white drapery dropped from the roof; while the floor below has its rough pavement of stalagmite, that stands up, wherever the drops descend, in rounded prominences, like the bases of columns. The marvel has become somewhat old-fashioned since the days when Buchanan described the dropping cave of Slams, — 'where the water, as it descends drop by drop, is converted into pyramids of stone,' — as one of the wonders of Scotland, and deemed it necessary to strengthen the credibility of his statement by adding, that he had been 'informed by persons of undoubted veracity that there existed a similar cave among the Pyrenees.' Here, however, is a puzzle to exercise our ingenuity. Some of the minuter stalactites of the roof, after descending perpendicularly, or at least nearly so, for a few inches, turn up again, and form a hook, to which one may suspend one's watch by the ring; while there are others that form a loop, attached to the roof at both ends. Pray, how could the descending drop have returned upwards to form the hook, or what attractive power could have drawn two drops together, to compose the elliptical curve of the loop? The problem is not quite a simple one. It is sufficiently hard at least, as it has to deal with only half-ounces of rock, to inculcate caution on the theorists who profess to deal with whole continents of similar material. Let us examine somewhat narrowly. Dark as the recess is, and though Vegetation fails full fifty feet nearer the entrance than where we now stand, the place is not without its inhabitants. We see among the dewy damps of the roof the glistening threads of some minute spider, stretching in lines or depending in [272] loops. And just look here. Along this loop there runs a single drop. Observe how it descends, with but a slight inclination, for about two inches or so, and then turns round for about three quarters of an inch more; observe further, that along this other loop there trickle two drops, one on each side; that, as a consequence of the balance which they form the one against the other, their descent has a much greater sweep; and that, uniting in the centre, they fall together. We have found a solution of our riddle, and received one proof more of the superiority of the simple art of seeing over the ingenious art of theorizing.

But let us proceed to the proper business of the excursion. We have provided ourselves with tools for digging; and, selecting a spot some thirty feet within the cavern, where the bottom seems composed of a damp dark mould, we set ourselves, with spade and pick-axe, to penetrate to the sea-gravel beneath. The soil yields as easily to the tool as a piece of garden-mould; and turning it up to the light in cubical adhesive masses, we find it consisting of an impalpable brown earth, that exactly resembles raw umber. We have fallen on a bed of pure guano, not quite so rich, perhaps, as that which our agriculturists export from the rocky islets of South America at the rate of about fourteen pounds per ton, for it must have been formed originally of vegetable, not animal matter, and we find that it lacks the strong ammoniacal smell of the guano produced by predacious water-birds; but judging from its appearance, and from the high estimate formed of old of the dung of pigeons as a manure, it must be of value enough to deserve removal from the damp unproductive floor of the Doocot. We find the bed which it composes extending downwards from two to three feet, and filling the cavern from side to side. A rock-gravel lies below, hardened into an imperfect breccia by a ferruginous cement; but the rotting moisture exuded from the guano has been unfavourable, apparently, to the [273] preservation of shells, and we find that it contains nothing organic. We again remove to the inner recesses of the cave. Mark, first, that peculiar appearance along the sides. There stands out, at the height of about four feet from the present floor, what seems a rude projecting cornice of rock gravel, bound together by the stalactitical cement: the projection at one point somewhat exceeds eighteen inches; and we find it bearing short-stemmed stalagmites atop, just like the rugged pavement below. To use a homely but apt illustration, the appearance is that presented by the lower part of a tallow-candle that had been burning exposed to a current of air, with its grease running down in ridges on the sides, and then spreading out on the margin of the meta socket, when, after raising it out of the candlestick, we see the lower accumulation projecting from it like a cornice. That line of projecting gravel indicates the level at which the floor of the cavern once stood. If we remove the looser parts of the present floor, we shall find its place indicated by just a similar line of projection. The loose sea-gravel could have adhered to the sides only by having formed the part of the floor in contact with them, until the stalagmitical substance had taken effect upon it, by binding it into a mass, and fixing it where it had lain. Let us break into one of the projections. We find it a true breccia, thickly interspersed with such fragments of shells as we may pick up by hundreds in the neighbouring sea-caves, where the incessant beat of the surf on the hard rocks against which it dashes breaks them into rounded fragments. There, for instance, is a massy little bit of the strong smooth buckie (Fusus Antiqaus), the largest of British univalves; and there a fragment equally massy of the Icelandic Venus, — both of them productions of the oceans, and of such rivers as the Firths of Cromarty and Dornoch. The materials of the projecting cornice are those of a cavern-beach much exposed to the roll of the surf.

[274] Let us now see what our several points of circumstantial evidence amount to. First, then, the bottom of the cave must have stood at one time at least four feet over its present level, and at least fourteen feet over the level of the two sea-caves outside; and yet, just as the sea now covers them, must the sea at that remote period have covered it. The incessant wave must have resounded along these silent walls as it dashed sullenly onwards, and awakened all their echoes with its harsh rattle as it rolled back. The cavern, at that early time, like all the other deep-sea caves of the coast, could have had no crust of stalactites : its sides and roof must have been as dark and bare as the sides and roofs of the caves outside, where the spray washes away every film of calcareous matter ere it has been deposited for half a day. A sudden elevation of the coast took place, and sudden it must have been, for the loose gravel beach, with its finely comminuted shells, was at once raised beyond the influence of the tides; the stalactitical ridges began to form on the walls, and the sea-gravel to consolidate — where these terminated beneath, and the petrifying water oozed through — into the brecciated cornice. But the waves from the lower line had been encroaching inwards, bit by bit, from the cavern's mouth, washing down the floor to their own reduced level, until they had at length scooped it all out, and left but the hardened projections to mark where it had stood. The cave, though now occupied by only the higher tides, had again become, in some sort, a sea-cave, when a second elevation of the land raised it to its present level. The covering of stalactites thickened along its sides; its minute mosses lived, died, and became marble; and, as age succeeded age, the dark recesses in its roof were cheered by the unerring affections of instinct; and brood after brood, reared with assiduous labour to maturity, went forth, some again to return to their hereditary cells, some to take up their abodes with man. I need scarce say, [275] that the rock, or white-backed dove, is the original of our domestic species.


WE find that there leaned against one of the precipices of the Southern Sutor, now washed by the spring-tides, a talus of loose débris, such as we see still leaning against the precipices of the old coast line, and that a calcareous spring, dropping upon it from an upper ledge, had, in the course of years, converted its apex into a hard breccia, and cemented it to the rock; while the base below remained incoherent as at first. During this period it must have lain beyond the sweep of the waves. But a change of level took place; the waves came dashing against the loose débris, and swept it away; and all that now remains of the talus is the consolidated apex, projecting about three feet from the rock. Under another precipice of the Cromarty Sutor we find a line of consolidated débris, — which, like the breccia of the apex, must have been the work of a calcareous spring, — running out about fifty feet into the ebb, where it is altogether impossible it could have formed now. The spring must have flowed downwards for these fifty feet ere it reached the sea; for no sooner could it have touched the latter than its Waters would have been diffused and lost; and, even could they have avoided such diffusion, the waves must have prevented the loose gravel on which the calcareous matter acted from remaining sufficiently stationary for a single tide. In each of these cases is the value of the evidence enhanced by the circumstances in which it is given. Both the talus and the brecciated line were formed on a basis of granitic rock, so hard that it strikes fire with steel, and which only a general change of level could have let down to the influence of the tide, or elevated over it.



THERE is a stiff blue clay much used in Cromarty and the neighbourhood for rendering the bottom of ponds water-tight, and the foundations of cellars impervious to the land-springs, and which, save for its greater tenacity, much resembles the blue boulder-clay of our Coal Measures. It is found in the ebb at half-tide, in a bed varying from eighteen inches to three feet in thickness, which overlies the red boulder-clay, and contains minute fragments of shells, too much broken to be distinguished. I had deemed it a sort of re-formation from strata of a greyish-coloured alumi nous shale, which occur in the Old Red Sandstone, and are laid bare in the neighbourhood by the sea. The waves dash against them, and then roll back turbid with the lighter particles, to deposit these in the deep still water outside. But in the place at present occupied by the bed the waves could not have deposited them; it is so much exposed to the surf, that the deposit is gradually wearing down under the friction, and it must have been formed, therefore, at a lower level, and when the sea beat against the ancient beaches. We find further proof that such must have been the case in a soft stratum of grey, shaly sandstone, which rises through the bed, and which is thickly perforated by cells of the Pholas candidus, containing in abundance the dead shells, but which has been elevated to a too high place to form any longer a fit habitat for the living animals. I had often — examined the fragmentary shells of this clayey layer, in the hope of being able to elicit from them somewhat regarding the history of a deposit older than our present coast line, yet newer than our boulder-clay; but I had hitherto found themi in every case too comminuted to [277] yield the necessary evidence. I now succeeded, however, in detecting the same deposit under the Northern Sutor, in the same close neighbourhood as on the Cromarty side to the grey aluminous shale of the Old Red Sandstone, to which it seems to have owed its origin, and abounding in organisms marine and terrestrial. All are recent. I found it containing cones of our common Scotch fir, hazel-nuts, fiagments of alder and oak, shells of the common mussel much decomposed, and shells, too, of one of the Gaper family (Myœ arenariœ), still lying in pairs. The blue adhesive clay in which they are embedded can scarce be distinguished from that of the Lower Lias of Eathie; the sets of organisms in the two deposits are also the same, — indicating that their deposition must have taken place under similar conditions. The Lias, like the recent clay, has its cones, its bits of wood, and its marine bivalves lying in pairs; and the sole difference that obtains between them is, that while the cones, and wood, and bivalves of the blue clay are all existences of the present time, the cones, and wood, and bivalves of the Lias represent classes of organic beings that have long since passed into extinction. This clay-bed of the Northern Sutor is one of the best places I know for the young geologist taking his first lesson upon. I deemed it of interest chiefly as corroborative of the fact that our raised beaches on the shores of the Cromarty and Moray Firths belong to exactly the present state of things; nay, that for a very considerable period ere their elevation, when the blue bed was forming in comparatively deep water, both sea and land were stored with their existing productions.


THERE are two several localities in which, after acquainting one's-self with the glacial moraines of Brora, one may [278] examine with advantage the glacial moraines of the neighbourhood of Cromarty. One of these we find in the parish of Logie, not a hundred yards distant from the great coach road; the other, in the parish of Nigg, on one of the slopes in which the lofty ridge whose south-western termination forms the Northern Sutor sinks at its north-eastern boundary into the plain of Easter Ross. The Logie moraine extends, for full three quarters of a mile, in a line parallel to the mountain range from which its glacier must have descended. There is a furzy level in front, mottled over with groups of cottages; the moraine, — thickly planted with fir, and amid whose sheltering hollows the gipsies' tent may be seen in the warmer months, and the houseless Free Church congregation at this inclement season, — forms a long undulating ridge, in what a painter would term the middle ground of the landscape; while on the swelling acclivities behind, over which the icy plane must have once extended, we see woods, and fields, and stately manor-houses, and, high above all, the heathy mountain ridge, where the sky seems resting on the land. I have not seen the rock laid bare in any part of the cultivated tract which intervenes between the moraine and the upland ridge; but I entertain little doubt that its surface will be found to bear the characteristic groovings and polishings of the glacial period. The moraines of the hill of Nigg, as might be premised from the lower elevation and narrower slopes of the eminence from which their glacier descended, are of small extent compared with the moraine of Logie. There is, however, one of the number, a beautiful grassy Tomhan, fringed at the base with its thickets of dwarf-birch and hazel, that was deemed commanding enough, in some early age, to be selected as the site of a hill-fort, still known to tradition as the Danish camp, and whose double mound of turf we may still see encircling the summit. It must have been a dreary period when the great glacier of Logie, sloping towards the south, [279] and the lesser glacier of the hill of Nigg, sloping towards the north, saw themselves reflected in the separating strait of sea which at this remote period flowed through the flat valley between. The valley is still occupied for half its length by a sandy estuary, known as the Sands of Nigg, which ere the upheaval of the higher beaches, must have existed as a shallow channel, through which the Firth of Cromarty, — then a double-mouthed arm of the sea, with the hill of Nigg as a mountainous island in the midst, — communicated with the Moray Firth beyond.


THERE are scarce any of the appearances with which the geologist is conversant more mysterious than the immense accumulations of shells which he occasionally finds, as in some parts of Sweden, separated from all extraneous matter, as if they had been subjected to some sifting process, — cleaned, as it were, and laid by; and it has long been a question with him how this sifting process has been effected. The theory that the accumulation had been heaped up by great floods, through which substances of the same specific gravity were huddled together, has been the commonly accepted one; but who ever saw a flood, however great, that did not cast down its mud and its clay among its transported shells, or that had not mingled them, in the process of removal, with its lighter gravels or its sand? In the flat estuary of Nigg, I have seen the sifting process effected through a simple but adequate agency. For about two miles from where the estuary opens into the Cromarty Firth, its wild tracts of yielding sand are thickly occupied by the shells that love such localities, — in especial, by the common cockle. Almost every tide, when the animals are in season, furnishes its vast quantities for the [280] markets of the neighbouring towns, and still the supply keeps up ample as at first. Now the tracts of sand which they inhabit, if not properly quicksands, are at least extremely loose, especially when covered by the tide; and though the creatures succeed, so long as they live, in maintaining their proper place in them within a few inches of the surface, no sooner do they die than the shells begin gradually to sink downwards through the unsolid mass, till, reaching, at the depth of about six feet, a firmer stratum, they there accumulate, and form a continuous bed. The work of accumulation has been going on for many centuries; generation after generation has been dying, to undergo this process of burial, — this process of subarenaceous deposition, if I may so speak; and there are places in the estuary in which the shelly stratum has risen to within a foot or two of the surface. It forms a sort of quarry of shells; and when, about thirty years ago, there was a lime-work established in the neighbourhood, many thousand cart-loads were dug out and burned into lime. I had frequent occasion, some five or six years since, to pass through the estuary at seasons when the mere amateur would have perhaps stayed at home. There runs through it a stream of fresh water, that drains the flat fields and scattered lochans of Easter Ross; and on one of my winter journeys, after a sudden thaw, accompanied by heavy rains, I found the stream swollen to the size of a considerable river, and its bed excavated beneath the usual level some three or four feet, with the sectional line of sand and shells through which it had cut standing up over it like a wall. There was first, reckoning downwards, from a foot to eighteen inches of pure sand; and next, from two feet to two feet and a half of dead shells. The sandy tract all around, for many hundred acres in extent, used to be partially covered with water; every furrow of the ripples, and every depression of the surface, borrowed its full from the receding tide, and, [281] from the general flatness, retained it till its return. But on this Occasion, the surface-water had found an unwonted drainage, through the upright sectional front, into the newly excavated bed of the stream. It sank through the upper arenaceous layer as through a filtering stone, and then came rushing through the stratum of shells underneath, brown with the sand which it swept from their interstices. Nor could there be a completer sifting process. For yards and roods together the shells were as thoroughly divested of the sandy matrix in which they had lain as if they had been carefully washed in a sieve. I was bold enough to infer from the phenomenon at the time, that the problem of the unmixed accumulations of shells may be, in at least some cases, not so difficult of solution as has been hitherto supposed. One has but to take for granted conditions such as those of the estuary of Nigg, — the incoherent bed, half a quicksand, and the subarenaceous deposition, — to account for their original production, and the superadded conditions of the surface-water and the free drainage, to account for their after clearance of extraneous matter.


IN consolidated slopes it is not unusual to find remains, animal and vegetable, of no very remote antiquity. I have seen a human skull dug out of the reclining base of a clay bank, once a precipice, fully six feet from under the surface. It might have been deemed, not without a degree of plausibility, the skull of some long-lived contemporary of Enoch, — perchance that of one of the accursed race, —

'Who sinned and died before the avenging flood.'
Nay, a fine theory was in the act of being formed regarding it, which affected the whole deposit; but, alas! the labourer dug a little further, and struck his pickaxe against an old [282] Gothic rybat, that lay deeper still. There could be no mistaking the character of the chamfered edge that still bore the marks of the tool, nor that of the square perforation for the lock-bolt; and the rising theory straightway stumbled against it and fell. Both rybat and skull had come from an ancient burying-ground, situated on a projecting angle of the table, and above.


ON level moors, where the rain-water stagnates in pools, and a thin layer of mossy soil produces a scanty covering of heath, we find the underlying clay streaked and spotted with patches of white. As in the spots and streaks of the Red Sandstone formations, Old and New, the colouring matter has been discharged without any accompanying change having taken place in the mechanical structure of the substance which it pervaded; for we find the same mixture of arenaceous and aluminous particles in the white as in the red portions. And the stagnant water above, acidulated, perhaps, by its various vegetable solutions, seems to have been in some way connected with these appearances. In almost every case in which a crack through the clay gives access to the oozing moisture, we find the sides bleached, for several feet downwards, to nearly the colour of pipe-clay; we find the surface, too, when divested of the soil, presenting for yards together the appearance of sheets of half-bleached linen. Now, the peculiar chemistry through which these changes are effected might be found to throw much light on similar phenomena in the older formations. There are quarries in the New Red Sandstone in which almost every mass of stone presents a different shade of colour from that of its neighbouring mass, and quarries in the Old Red, whose strata we find streaked and spotted [283] like pieces of calico. And their variegated aspect seems to have been communicated in every instance, not during deposition, nor after they had been hardened into stone, but when, like the boulder-clay, they had existed in an intermediate state.


ALL the travelled boulders of the north do not seem associated with the clay: we find them occurring, in some instances, in an overlying gravel, and in some instances resting at high levels on the bare rock. I have seen, on the hill of Fyrish, — a lofty eminence of the Lower Old Red which overlooks the upper part of the Cromarty Firth, — a boulder of an exceedingly beautiful, sparkling hornblende, reposing on a stratum of yellow sandstone, fully a thousand feet over the sea, where there is not a particle of the clay in sight. We find these travellers furnishing specimens of almost all the primary rocks of the country, — its gneisses, schistose and granitic, its granites, red, white, and grey, its hornblendic and micaceous schists, and occasionally, though more rarely, its traps. The stone most abundant among them, and which is found occurring in the largest masses, is a well-marked granitic gneiss, in which the quartz is white, and the feldspar of a pink colour, and in which the mica, intensely black, exists in oblong accumulations, ranged along the line of stratification in interrupted layers. No rock of the same kind is to be found in situ nearer than thirty miles. We find granitic boulders of vast size abundant in the neighbourhood of Tam, especially where the coach-road passes towards the west through a piece of barren moor, and on the range of sea-beach below. One enormous block, of a form somewhat approaching the cubical, is large enough, and seems solid enough, to admit [284] of being hewn into the pedestal of some colossal statue; but instead of being thus appropriated to form part of a monument, it has lately been converted of itself into a whole monument. When I last passed the way, I found it dedicated, in an inscription of nine-inch letters, 'to the memory of the immortal Scott.' Nature had dedicated it to the memory of one of her great revolutions ages before; but since the dedicator had determined on adding, in Highland fashion, a stone to the cairn of Sir Walter, it would certainly have been no easy matter to have added to it a nobler one.