Problem first propounded to the Author in a Quarry —
The Quarry's Two Deposits, Old Red Sandstone and Boulder-Clay — The
Boulder-Clay formed wbile the Land was subsiding — The Groovings and
Polishings of the Rocks in the Lower Parts of the Country evidences of
the fact — Sir Charles Lyell's Observations on the Canadian Lake
District — Close of the Boulder-Clay Record in Scotland — Its
Continuance in England into the Pliocene Ages —
The Trees and Animals of the Pre-Glacial Periods — Elephants' Tusks
found in Scotland and England regarded as the Remains of Giants —
Legends concerning them — Marine Deposits beneath the Pre-Glacial
Forests of England — Objections of Theologians to the Geological Theory
of the Antiquity of the Earth and of the Human Race considered — Extent
of the Glacial Period in Scotland —
Evidences of Glacial Action in Glencoe, Gareloch, and the Highlands of
— Scenery of Scotland owes its Characteristics to Glacial Action — The
of Elevation which succeeded the Period of Subsidence — Its Indications
Raised Beaches and Subsoils — How the Sub-soils and Brick Clays were
— Their Economic Importance — Boulder- Stones interesting Features in
Landscape — Their prevalence in Scotland — The more remarkable
Boulders described — Anecdotes of the 'Travelled Stone of Petty' and
Standing-Stone of Torboll — Elevation of the Land during the
Period which succeeded the Period of the Boulder-Clay — The Alpine
of Scotland the Vegetable Aborigines of the Country — Panoramic View of
Pleistocene and Post-Tertiary Periods — Modem Science not adverse to
Development of the Imaginative Faculty.
I REMEMBER, as distinctly as if I had quitted it but yesterday, the quarry in which, some two-and-thirty years ago, I made my first acquaintance with a life of toil and restraint, and at the same time first broke ground as a geologist. It formed a section about thirty feet in height by eighty or a hundred in length, in the front of a furze-covered bank, a portion of the old coast line; and presented an under bar of a deep-red sandstone arranged in nearly horizontal strata, and an upper bar of a pale-red clay roughened by projecting pebbles and boulders. Both deposits at the time were almost equally unknown to the geologist. The deep-red  sandstone beneath formed a portion of that ancient Old Red system which represents, as is now known, the second great period of vertebrate existence on our planet, and which has proved to the palæontologist so fertile a field of wonders: the pale clay above was a deposit of the boulder-clay, resting on a grooved and furrowed surface of rock, and containing in abundance its scratched and polished pebbles. Old Red Sandstone and boulder-clay! a broad bar of each ; — such was the compound problem propounded to me by the Fate that dropped me in a quarry; and I gave to both the patient study of years. But the older deposit soon became frank and communicative, and yielded up its organisms in abundance, which furnished me with many a curious little anecdote of their habits when living, and of the changes which had passed over them when dead; and I was enabled, with little assistance from brother geologists, to give a history of the system to the world more than ten years ago. The boulder-clay, on the contrary, remained for years invincibly silent and sullen. 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 grey (according to the prevailing colour of the rocks on which it rested), and might mark their water-rolled boulders of all kinds and sizes sticking out in bold relief from the surface, like the protuberances that roughen the rustic basements of the architect; but I had no 'Open, Sesame' to form vistas through them into the recesses of the past. And even now, when I have, I think, begun to understand the boulder-clay a little, and it has become sociable enough to indulge me with occasional glimpses of its early history in the old glacial period, — glimpses of a half-submerged land, and an iceberg mottled sea, turbid with the comminuted débris of the rocks  below, you will see how very much I have had to borrow from the labours of others, and that in worming my way into its secret, there are obscure recesses within its precincts into which I have failed to penetrate. Let us now, however, resume its half-told story.
There are appearances which lead us to conclude, that during the formation and deposition of the boulder-clay, what is now Scotland was undergoing a gradual subsidence, — gradually foundering amid the waves, if I may so speak, like a slowly-sinking vessel, and presenting, as century succeeded century, hills of lower and yet lower altitude, and an ever lessening area. I was gratified to find, that when reasoning out the matter for myself, and arriving at this conclusion from the examination of one special set of data, Mr. Charles Darwin was arriving at the same conclusion from the consideration of a second and entirely different set; and Sir Charles Lyell, — from whom, on the publication of my views in the Witness newspaper some four years since, I received a kind and interesting note on the subject, — had also arrived at the same conclusion — North America being the scene of his observations — from the consideration of yet a third and equally distinct set. And in the Geological Journal for the present year, I find Mr. Joshua Trimmer and Mr. Austin arriving, from evidence equally independent, at a similar finding. We have all come to infer, in short, that previous to the Drift period the land had stood at a comparatively high level, — perhaps higher than it does now; that ages of depression came on, during which the land sank many hundred feet, and the sea rose high on the hill-sides; and that during these ages of depression the boulder-clay was formed. Let me state briefly some of the considerations on which we found.
The boulder-clay, I thus reasoned with myself, is generally found to overlie more deeply the lower parts of the country than those higher parts which approach its upper limit; and  yet the rocks on which it rests, in some localities to the depth of a hundred feet at even the level of the sea, bear as decidedly their groovings and polishings as those on which, eight hundred feet over the sea level, it reposes to but the depth of a yard or two. Now, had a rising land been subjected piecemeal to the grinding action of the icebergs, this would not have been the case. The higher rocks first subjected to their action would of course bear the groovings and furrowings; but the argillaceous dressings detached from them in the process, mixed with the stones and pebbles which the ice had brought along with it, would necessarily come to be deposited in the form of boulder-clay on the lower rocks; and ere these lower rocks could be brought, by the elevation of the land, within reach of the grinding action of the icebergs, they would be so completely covered up and shielded by the deposit, that the bergs would fail to come in contact with them. They would go sweeping, not over the rocks themselves, but over the clay by which the rocks had been covered up; and so we may safely infer that, had the boulder-clay been formed during an elevating period, the lower rocks, where thickly covered by the clay, would not be scratched and grooved as we now find them, or, where scratched and grooved, would not be thickly covered by the clay. The existing phenomena, deep grooves and polished strke, on rocks overlaid at the present sea-level to a great depth by the boulder-clay, demand for their production the reverse condition of a sinking land, in which the lower rocks are first subjected to the action of the icebergs, and the higher rocks after them. The quarrier, when he has to operate on some stratum of rock on a hill-side, has to commence his labours below, and to throw the rubbish which he forms behind him, leaving ever an open face in front; for, were he to reverse the process, and commence above, the accumulating débris, ever seeking downwards, would at length so choke up the working as to arrest his labours. And such, we infer from  the work done, must have been the course of operations imposed by the conditions of a sinking land on the icebergs of the glacial period: they began their special course of action at the hill-foot, and operated upon its surface upwards as the sea arose. Again, Mr. Darwin's reasonings were mainly founded on the significant fact, that in numerous instances travelled boulders of the ice period may be found on levels considerably higher than those of the rocks from which they were originally torn. And though cases of transport from a lower to a higher level could and would take place during a period of subsidence, when the sea was rising or the land sinking, it is impossible that it could have taken place during an elevating period, when the sea was sinking or the land rising.1 A flowing sea, to use a simple illustration, frequently carries shells, pebbles, and sea-weed from the level of ebb to the level of flood ; — it brings them from a low to a high level : whereas an ebbing sea can but reverse the process, by bringing them from a high level to a low.
For the facts and reasonings of Sir Charles Lyell on the subject, I must refer you, — as they are incapable of being abridged without being injured — to that portion of his first work of Travels in America which treats of the Canadian Lake District. But the following are his conclusions
'First,' he says, 'the country acquired its present geographical configuration, so far as relates to the older rocks, under the joint influence of elevating and denuding operations. Secondly, a gradual submergence then took place, bringing down each part of the land successively to the level of the waters, and then to a moderate depth below them. Large islands and bergs of floating ice came from the north, which, as they grounded on the coast and on shoals, pushed along all loose materials of sand and pebbles, broke off all angular and projecting points of rock, and, when fragments of hard
1 See Mr. Trimmer's last paper on Boulder-Clays, Journal of the Geological Society, May 1858, p. 171. — W. S.
 stone were frozen into theirlower surfaces, scooped outgrooves in the subjacent solid strata. Thirdly, after the surface of the rocks had been smoothed and grated upon by the passage of innumerable icebergs, the clay, gravel, and sand of the Drift were deposited; and occasionally fragments of rock, both large and small, which had been frozen into glaciers, or taken up by coast-ice, were dropped here and there at random over the bottom of the ocean, wherever they happened to be detached from the melting ice. Finally, the period of re-elevation arrived, or of that intermittent upward movement in which the old coast lines were excavated and the ancient sand bars or osars laid down.' Such are the conclusions at which Sir Charles Lyell arrived a few years since respecting the Canadian Lake District; and he states, in the note to which I have referred, that he has ever since been applying them to Scotland. Our country, during the chill and dreary period of the boulder-clay, seems to have been settling down into the waves, like the vessel of some hapless Arctic explorer struck by the ice in middle ocean, and sinking by inches amid a wild scene of wintry desolation.
There are a few detached localities in Scotland where the remains of beds of stratified sand and gravel have been detected underlying the boulder-clay; and in some of these in the valley of the Clyde, Mr. Smith of Jordanhill found on a late occasion shells of the same semi-arctic character as those which occur in the clay itself. And with these stratified beds the record in Scotland closes; whereas in England we find it carried interestingly onward from the Pleistocene period, first into the newer, and then into the older, Pliocene ages. I stated incidentally in my former address, that some of the mosses of the sister kingdom, unlike those of our own country, are older than the Drift period; and, from the existence of these under the Drift gravels and brown clay, it has been inferred by Mr. Trimmer, that as the trees which enter into their composition grew  upon the surface of what is now England, where they now lie, previous to the period of the boulder-clay, and as the boulder-clay is, as shown by its remains, decidedly marine, it must have been deposited during a period of depression, when what had been a forest-bearing surface was lowered beneath the level of the sea. None of the trees of these ancient pre-glacial forests seem to be of extinct species: the birch and Scotch fir are among their commonest forms, especially the fir. I find it stated, however, as a curious fact, that along with these, the Abies Excelsa, or Norwegian spruce-pine, is found to occur, — a tree which, though introduced by man into our country, and now not very rare in our woods, has not been of indigenous growth in any British forest since the times of the boulder-clay. Though the species continued to live in Norway, it became extinct in Britain ; and it has been suggested, that as it was during the Drift period that it disappeared, it may have owed its extirpation to the depression of the land, while its contemporaries the birch and fir were preserved on our northern heights. When this Norwegian pine flourished in Britain, the island was inhabited by a group of quadrupeds now never seen associated, save perhaps in a menagerie. Mixed with the remains of animals still native to our country, such as the otter, the badger, and the red deer, there have been found skeletons of the Lagomy, or tail-less hare, now an inhabitant of the cold heights of Siberia, and horns of the rein-deer, a species now restricted in Europe to Northern Scandinavia, and those inhospitable tracts of western Russia that border on the Arctic Sea. And with these boreal forms there were associated, as shown by their bones and tusks, the elephant, the rhinoceros, and the hippopotamus, all, however, of extinct species, and fitted for living under widely different climatal conditions from those essential to the well-being of their intertropical congeners.1 Scotland,
1 The true mammoth, with the tichorine rhinoceros and the musk buffalo, [051f] are the leading types of the mammalian fauna of the Glacial Drift epoch. The remains of hippopotamus would be washed out of older beds. — W. S.
 though it has proved much less rich than England in the remains of the early Pleistocene mammals, has furnished a few well-attested elephantine fossils. In the summer of 1821, in the course of cutting the Union Canal, there was found in the boulder-clay near Falkirk, on the Clifton Hall property, about twenty feet from the surface, a large portion of the tusk of an elephant, three feet three inches in length and thirteen inches in circumference; and such was its state of keeping when first laid open, that it was sold to an ivory-turner by the labourers that found it, and was not rescued from his hands until a portion of it had been cut up for chessmen. Two other elephants' tusks were found early in 1817 at Kilmaurs1 in Ayrshire, on a property of the Earl of Eglinton, — one of them so sorely decayed that it could not be removed; but a portion of the other, with the rescued portion of the Falkirk tusks, may be seen in the Museum of our Edinburgh University, which also contains, I may here mention, the horn of a rhinoceros, found at the bottom of a morass in Forfarshire, but which, in all probability, as it stands alone among the organisms of our mosses, had been washed out of some previously formed deposit of the Drift period. Scotland seems to have furnished several other specimens of elephantine remains; but as they were brought to light in ages in which comparative anatomy was unknown, and men believed that the human race had been of vast strength and stature in the primeval ages, but were fast sinking into dwarfs, they were regarded as the remains of giants. Some of the legends to which the
1 At a later period (December 1829), similar elephantine tusks were found thirty-four feet beneath the surface, in boulder-clay overlying the quarry of Greenhill, also in Kilmaurs parish; and they may now be seen in the Hunterian Museum, Glasgow.
 bones of these supposed giants served to give rise in England occupy a place in the first chapter of the country's history, as told by the monkish chroniclers, and have their grotesque but widely-known memorials in Gog and Magog, the wooden giants of Guildhall: our Scottish legends of the same class are less famous; but to one of their number, — charged with an argument in behalf of the temperance cause of which our friends the teetotallers have not yet availed themselves, — I may be permitted briefly to refer, in the words of one of our elder historians. 'In Murray land,' says the believing Hector Boece, 'is the Kirke of Pette, quhare the bones of Litell Johne remainis in gret admiration of pepill. He hes bene fourtene feet of hicht, with squaire membres effering thairto. Six yeirs afore the coming of this work to licht (1520) we saw his henche bane, as meikle as the haill banes of ane manne; for we schot our arme into the mouthe thairof; be quhilk appeirs how strang and squaire pepill greu in oure regeoun afore thay were effeminat with lust and intemperance of mouthe.'
Under these pre-glacial forests of England there rests a marine deposit, rich in shells and quadrupedal remains, known as the Norwich or Mammaliferous Crag; and beneath it, in turn, lie the Red and Coralline Crags — members of the Pliocene period. In the Mammaliferous Crag there appear a few extinct shells, blent with shells still common on our coasts. In the Red Crag the number of extinct species greatly increases, rising, it is now estimated, to thirty per cent. of the whole; while in the Coralline Crag the increase is greater still, the extinct shells averaging about forty per cent.1 In these deposits some of our best-known molluscs appear in creation for the first time. The common edible oyster (Ostrea edulis) occurs in
1 The known species of shells in the Coralline Crag amount to three hundred and forty. Of these, seventy-three are living British species. See Woodward's Manual, part iii. p. 421. — W. S.
 the Coralline Crag, but in no older formation, and with it the great pecten (Pecten maximus), the horse mussel (Modiola vulgaris), and the common whelk (Buccinum undatum). Other equally well-known shells make their advent at a still later period; the common mussel (Mytilus edulis), the common periwinkle (Littorina littorea), and, in Britain at least, the dog-whelk (Purpura lapillus), first appear in the overlying Red Crag, and are not known in the older Coralline formation. By a certain very extended period, represented by the Coralline Crag, the edible oyster seems to be older than the edible mussel, and the common whelk than the common periwinkle; and I call your special attention to the fact, as representative of a numerous class of geological facts that bear on certain questions of a semi-theological character, occasionally mooted in the religious periodicals of the day. There are few theologians worthy of the name who now hold that the deductions of the geologists regarding the earth's antiquity are at variance with the statements of Scripture respecting its first creation, and subsequent preparation for man. But some of them do seem to hold that the scheme of reconciliation, found sufficient when this fact of the earth's antiquity was almost the only one with which we had to grapple, should be deemed sufficient still, when science, in its onward progress, has called on us to deal with this new fact of the very unequal antiquity of the plants and animals still contemporary with man, and with the further fact, that not a few of them must have been living upon the earth thousands of years ere he himself was ushered upon it, — facts of course wholly incompatible with any scheme of interpretation that would fix the date of their first appearance only a few natural days in advance of that of his own. We have no good reason to hold that the human species existed upon earth during the times of the boulder-clay: such a belief would conflict, as shown by the antiquity of the ancient and existing coast lines, with our  received chronologies of the race. But long previous to these times, the Norwegian spruce pine and the Scotch fir were natives of the pre-glacial forests of our country; at even an earlier period the common periwinkle and edible mussel lived in the seas of the Red Crag deposits; and at a still earlier time, the great pecten, the whelk, and the oyster, in those of the Coralline Crag. We can now no more hold, as geologists, that the plants and animals of the existing creation came into being only a few hours or a few days previous to man, than that the world itself came into being only six thousand years ago; and we do think we have reason to complain of theologians who, ignorant of the facts with which we have to deal, and in no way solicitous to acquaint themselves with them, set themselves coolly to criticise our well-meant endeavours to reconcile the Scripture narrative of creation with the more recent findings of our science, and who pronounce them inadmissible, not because they do not effect the desired reconciliation, but simply because they are new to theology. They should remember that the difficulty also is new to theology; that enigmas cannot be solved until they are first propounded; that if the riddle be in reality a new one, the answer to it must of necessity be new likewise; and as this special riddle has been submitted to the geologists when the theologians were unaware of its existence, it must not be held a legitimate objection, that geologists, who feel that they possess, as responsible men, a stake in the question, should be the first to attempt solving it. If, however, it be, as I suspect, with our facts, not with our schemes of reconciliation, that the quarrel in reality lies, — if it be, in particular, with the special fact of the unequal antiquity of the existing plants and animals, and the comparatively recent introduction of' man, — I would fain urge the objectors to examine ere they decide, and not rashly and in ignorance to commit themselves against truths which every day must render more  palpable and clear, and which are destined long to outlive all cavil and opposition.
With respect to the antiquity of our race, we have, as I have said, no good grounds to believe that man existed upon the earth during what in Britain, and that portion of the Continent which lies under the same lines of latitude, were the times of the boulder-clay and Drift gravels. None of the human remains yet found seem more ancient than the historic period, in at least the older nations : it is now held that the famous skeletons of Guadaloupe belonged to men and women who must have lived since the discovery of America by Columbus; and if in other parts of the world there have been detected fragments of the human frame associated with those of the long extinct animals, there is always reason to conclude that they owe such proximity to that burying propensity to which I have already adverted, or to accidents resulting from it, and not to any imaginary circumstance of contemporarity of existence. If man buries his dead in the Gault or the London Clay, human remains will of course be found mingled with those of the Gault or the London Clay; but the evidence furnished by any such mixture will merely serve to show, not that the existences to which the remains belonged had lived in the same age, but simply that they had been deposited in the same formation. Nor can I attach much value to the supposed historic records of countries such as Egypt, in which dynasties are represented as having flourished thousands of years ere the era of Abraham. The chronicles of all nations have their fabulous introductory portions. No one now attaches any value to the record of the eighty kings that are said to have reigned in Scotland between the times of Fergus the First and Constantine the Bold; or to that portion of old English history which treats of the dynasty of Brutus the Parricide, or his wars with the giants. All the ancient histories have, as Buchanan tells us, in disposing of the English  claims, their beginnings obscured by fable; nor is it probable that the Egyptian history is an exception to all the others, or that its laboriously inscribed and painfully interpreted hieroglyphics were more exclusively devoted to the recording of real events than characters simpler of form and easier of perusal. If, as some contend, man has been a denizen of this world for some ten or twelve thousand years, what, I would ask, was he doing during the first five or six thousand? It was held by Sir Isaac Newton, that the species must have been of recent introduction on earth, seeing that all the great human discoveries and inventions, such as letters, the principles of geometry and arithmetic, printing, and the mariner's compass, lie within the historic period. The mind of man could not, he inferred, have been very long at work, or, from its very constitution, it would have discovered and invented earlier; and all history and all archaeological research bear out the inference of the philosopher. The older civilized nations lie all around the original centre of the race in Western Asia; nor do we find any trace of a great city older than Nineveh, or of a great kingdom that preceded in its rise that of Egypt. The average life of great nations does not exceed twelve, or at most fifteen; hundred years; and the first great nations were, we find, living within the memory of letters. Geology, too, scarce less certainly than Revelation itself, testifies that the last-born of creation was man, and that his appearance on earth is one of the most recent events of which it submits the memorials to its votaries.
But to return: The glacial or ice period in Scotland seems to have extended from the times of the stratified beds, charged with sub-arctic shells, which underlie the boulder-clay, until the land, its long period of depression over, was again rising, and had attained to an elevation less by only fifty or a hundred feet than that which it at present maintains. Such is the height over the sea level,  of the raised beach at Gamrie in Banffshire; and in it the arctic shells last appear. And to the greatly-extended sub-arctic period in Scotland there belong a class of appearances which have been adduced in support of a glacial as opposed to an iceberg theory. But there is in reality no antagonism in the case. After examining not a few of our Highland glens, especially those on the north-western coast of the country, I have arrived at the conviction, that Scotland had at one time its glaciers, which, like those of Iceland, descended along its valleys, from its inland heights, to the sea. And as in most cases certain well-marked accompaniments of the true glacier, such as those lateral and transverse moraines of detached rock and gravel that accumulate along their sides and at their lower terminations, are wanting in Scotland, it is inferred that great currents must have swept over the country since the period of their existence, and either washed their moraines away, or so altered their character and appearance that they can be no longer recognised as moraines. Of course, this sweeping process might have taken place during that period of profound subsidence when the boulder-clay was formed, and in a posterior period of more partial subsidence, which is held to have taken place at a later time and under milder climatal conditions, and which is said to have brought down the land to its present level from a considerably higher one. In many localities there rests over the true boulder-clay an argillaceous or gravelly deposit, in which the masses and fragments of rock are usually angular, and which, even where the boulder-clay is shell-bearing, contains no shells. There are other localities in which a similar deposit also underlies the boulder-clay; and these deposits, upper and lower, are in all probability the débris of glaciers that existed in our country during the ice-era, — the lower deposit being the débris of glaciers that had existed previous to the glacial period of subsidence, and the upper that of glaciers which had existed  posterior to it, and when the land was rising. The evidence is, I think, conclusive, that glaciers there were. I examined, during the autumn of last year, the famous Glencoe, and can now entertain no more doubt that a glacier once descended along the bottom of that deep and rugged valley, filling it up from side to side to the depth of from a hundred and fifty to two hundred feet, than that an actual glacier descends at the present day along the valley of the Aar or of the Grindelwald. The higher precipices of Glencoe are among the most rugged in the kingdom: we reach a cer tain level; and, though no change takes place in the quality of the rock, all becomes rounded and smooth, through the agency, evidently, of the vanished ice-river, whose old line of surface we can still point out from the continuous mark on the sides of the precipices, beneath which all is smooth, and above which all is rugged, and whose scratchings and groovings we can trace on the hard porphyry descending towards the Atlantic, even beyond where the sea occupies the bottom of the valley. The lines and grooves running in a reverse direction to those of the icebergs, for their course is towards the west, are distinctly discernible as far down as Ballachulish ferry. Similar marks of a great glacier in the valley of the Gareloch have been carefully traced and shrewdly interpreted by Mr. Charles M'Laren. But nowhere have I seen the evidence of glacial action more decided than in the Highlands of Sutherland, over which I travelled last August more than a hundred and fifty miles, for the purpose of observation. There is scarce a valley in that wild region, whether it open towards the northern or western Atlantic, or upon the German Ocean, that in this ungenial period was not cumbered, like the valleys of the upper Alps, by its burden of slowly-descending ice. Save where, in a few localities on the lower slopes of the hills, the true boulder clay appears, almost all the subsoil of the country, where it has a subsoil, is composed of a loose, unproductive glacial  débris; almost every prominence on the mountain-sides is rounded by the long protracted action of the ice; and in many instances the surfaces of the rocks bear the characteristic groovings and scratchings as distinctly as if it had per formed its work upon them but yesterday. Let me, however, repeat the remark, that the iceberg and glacial theories, so far from being antagonistic, ought rather to be regarded as equally indispensable parts of one and the same theory, — parts which, when separated, leave a vast amount of residual phenomena to puzzle and perplex, that we find fully accounted for by their conjunction. And why not conjoin them? The fact that more than four thousand square miles of the interior of Iceland are covered by glaciers, is in no degree invalidated by the kindred fact that its shores are visited every spring by hundreds of thousands of icebergs.
The glaciers of Scotland have, like its icebergs, contributed their distinctive quota to the scenery of the country. The smoothed and rounded prominences of the hills, bare and grey amid the scanty heath, and that often after a sudden shower gleam bright to the sun, like the sides and bows of windward-beating vessels wet by the spray of a summer gale, form well-marked features in the landscapes of the north-western parts of Sutherland and Ross, especially in the gneiss and quartz-rock districts. The lesser islets, too, of these tracts, whether they rise in some solitary lochan among the hills, or in some arm of the sea that deeply indents the coast, still bear the rounded form originally communicated by the ice, and in some instances remind the traveller of huge whales heaving their smooth backs over the brine. Further, we not unfrequently see the general outline of the mountains affected ; — all their peaks and precipices curved backwards in the direction whence the glacier descended, and more angular and abrupt in the direction towards which it descended. But it is in those groups of  miniature hills, composed of glacial débris, which so frequently throng the openings of our Highland valleys, and which Burns so graphically describes in a single line as
that perhaps the most pleasing remains of our ancient glaciers are to be found. They seem to be modified moraines, and usually affect regular forms, resembling in some instances the roofs of houses, and in some the bottoms of upturned ships; and, grouped thick together, and when umbrageous with the graceful birch, or waving from top to base with the light fronds of the lady-fern and the bracken, they often compose scenes of a soft and yet wild loveliness, from which the landscape gardener might be content to borrow, and which seem to have impressed in a very early age the Celtic imagination. They constitute the fairy Tomhans of Highland mythology; and many a curious legend still survives, to tell of benighted travellers who, on one certain night of the year, of ghostly celebrity, have seen open doors in their green sides, whence gleams of dazzling light fell on the thick foliage beyond, and have heard voices of merriment and music resounding from within; or who, mayhap, incautiously entering, have listened entranced to the song, or stood witnessing the dance, until, returning to the open air, they have found that in what seemed a brief half-hour half a lifetime had passed away. There are few of the remoter valleys of the Highlands that have not their groups of fairy Tomhans, — memorials of the age of ice.'Hillocks dropt in Nature's careless haste,'
After the lapse of ages, — but who can declare their number ? — the period of subsidence represented by the boulder-clay came to a close, and a period of elevation succeeded. The land began to rise; and there is a considerable extent of superficial deposits in Scotland which we owe to this period of elevation. It is the main object of the ingenious work of Mr. Robert Chambers on Raised  Beaches to show that there were pauses in the elevating process, during which the lines against which the waves beat were hollowed into rectilinear terraces, much broken, it is true, and widely separated in their parts, but that wonderfully correspond in height over extensive areas. It is of course to be expected, that the higher and more ancient the beach or terrace, the more must it be worn down by the action of the elements, especially by the descent of water-courses; and as the supposed beaches intermediate between the strongly-marked ancient coast line which I have already described at such length, and certain upper lines traceable in the moorland districts of the country, occur in an agricultural region, the obliterating wear of the plough has been added to that of the climate. After, however, all fair allowances have been made, there remain great diffi culties in the way. I have been puzzled, for instance, by the fact that Scotland presents us with but two lines of water-worn caves, — that of the present coast line, and that of the old line immediately above it. Mr. Chambers enumerates no fewer than fifteen coast lines intermediate between the old coast line and a coast line about three hundred feet over it; and in the range of granitic rocks which skirt on both sides the entrance of the Cromarty Firth, there are precipices fully a hundred yards in height, and broadly exposed to the stormy north-east, whose bases bear their double lines of deeply-hollowed caverns. But they exhibit no third, or fourth, or fifth line of caves. Equally impressible throughout their entire extent of front, and with their enclosed masses of chloritic schist and their lines of fault as thickly set in their brows as in their bases, they yet present no upper storeys of caves. Had the sea stood at the fifteen intermediate lines for periods at all equal in duration to those in which it has stood at the ancient or at the existing coast line, the taller precipices of the Crornarty Sutors would present their seventeen storeys  of excavations; and excavations in a hard granitic gneiss. that varied from twenty to a hundred feet in depth would form marks at least as indelible as parallel roads on the mountain sides, or mounds of gravel and débris overtopping inland plains, or rising over the course of rivers. The want of lines of caves higher than those of the ancient coast line would seem to indicate, that though the sea may have remained long enough at the various upper levels to leave its mark on soft impressible materials, it did not remain long enough to excavate into caverns the solid rocks.
But though the rise of the land may have been comparatively rapid, there was quite time enough during the term of upheaval for a series of processes that have given considerable variety to the subsoils of our country. Had the land been elevated at one stride, almost the only subsoil of what we recognise as the agricultural region of Scotland would have been the boulder-clay, here and there curiously inlaid with irregular patches of sand and gravel, which occur occasionally throughout its entire thickness, and which were probably deposited in the forming mass by icebergs, laden at the bottom with the sand and stones of some sea-beach, on which they had lain frozen until floated off, with their burdens, by the tide. But there elapsed time enough during the upheaval of the land, to bring its boulder-clay deposits piecemeal under the action of the tides and waves; and hence, apparently, the origin of not a few of our lighter subsoils. Wherever the waves act at the present time upon a front of clay, we see a separation of its parts taking place. Its finer argillaceous particles are floated off to sea, to be deposited in the outer depths; its arenaceous particles settle into sand-beds a little adown the beach; its pebbles and boulders form a surface stratum of stones and gravel, ex tending from the base of the scaur to where the surf breaks at the half-tide line. We may see a similar process of separation going on in ravines of the boulder-clay swept by  a streamlet. After every shower the stream comes down brown and turbid with the more argillaceous portions of the deposit; accumulations of sand are swept to the gorge of the ravine, or cast down in ripple-marked patches in its deeper pools; beds of pebbles and gravel are heaped up in every inflection of its banks; and boulders are laid bare along its sides. Now, a separation by a sort of washing process of an analogous character seems to have taken place in the materials of the more exposed portions of the boulder-clay, during the emergence of the land; and hence, apparently, those extensive beds of sand and gravel which in so many parts of the kingdom exist in relation to the clay as a superior or upper subsoil; hence, too, occasional beds of a purer clay than that beneath, divested of a considerable portion of its arenaceous components, and of almost all its pebbles and boulders. This washed clay, — a re-formation of the boulder deposit, — cast down mostly in insulated beds in quiet localities, where the absence of currents suffered the purer particles, held in suspension by the water, to settle, forms, in Scotland at least, — with, of course, the exception of the ancient fire-clays of the Coal Measures, — the true brick and tile clays of the agriculturist and architect. There are extensive beds of this washed clay within a short distance of Edinburgh; and you might find it no uninteresting employment to compare them, in a leisure hour, with the very dissimilar boulder-clays over which they rest. Unlike the latter, they are finely laminated: in the brick-beds of Portobello I have seen thin streaks of coal-dust, and occasionally of sand, occurring between the layers; but it is rare indeed to find in them a single pebble. They are the washings, in all likelihood, of those boulder-clays which rise high on the northern flanks of the Pentlands, and occur in the long flat valley along which the Edinburgh and Glasgow Railway runs, — washings detached by the waves when the land was rising, and which,  carried towards the east by the westward current, were quietly deposited in the lee of Arthur Seat and the neigh bouring eminences, — at that time a small group of islands. The only shells I ever detected in the brick-clay of Scotland occurred in a deposit in the neighbourhood of St. Andrews, of apparently the same age as the beds at Portobello.1 They were in a bad state of keeping; but I succeeded in identifying one of the number as a deep-sea Balanus, still thrown ashore in considerable quantity among the rocks to the south of St. Andrews. In this St. Andrews deposit, too, I found the most modern nodules I have yet seen in Scotland, for they had evidently been hardened into stone during the recent period; but, though I laid them open by scores, I failed to detect in them anything organic. Similar nodules of the Drift period, not unfrequent in Canada and the United States, are remarkable for occasionally containing the only ichthyolite found by Agassiz among seventeen hundred species, which still continues to live, and that can be exhibited, in consequence, in duplicate specimens, — the one fit for the table in the character of a palatable viand, — the other for the shelves of a geological museum in the character of a curious ichthyolite. It is the Mallotus villosus, or Capelen (for such is its market-name), a little fish of the arctic and semi-arctic seas. 'The Mallotus is abundant,' says Mr. James Wilson, in his admirable Treatise on Fishes, 'in the arctic seas, where it is taken in immense profusion when approaching the coasts to spawn, and it is used as the principal bait for cod. A few are cured and brought to this country in barrels, where they are sold, and used as a relish by the curious in wines.'
Let me next call your attention to the importance, in an economic point of view, of the great geologic events which gave to our country its subsoils, more especially the boulder clay. This deposit varies in value, according to the nature
1 See Note at the end of the Lectures.
 of the rocks out of which it was formed; but it is, even where least fertile, a better subsoil than the rock itself would have been; and in many a district it furnishes our heaviest wheat soils. To the sand and gravel formed out of it, and spread partially over it, we owe a class of soils generally light, but kindly; and the brick clays are not only of considerable value in themselves, but of such excellence as a subsoil, that the land which overlies them in the neighbourhood of Edinburgh still lets at from four to five pounds per acre. I suspect that, in order to be fully able to estimate the value of a subsoil, one would need to remove to those rocky lands of the south that seem doomed to hopeless barrenness for want of one. It is but a tedious process through which the minute lichen or dwarfish moss, settling on a surface of naked stone, forms, in the course of ages, a soil for plants of greater bulk and a higher order; and had Scotland been left to the exclusive operation of this slow agent, it would be still a rocky desert, with perhaps here and there a strip of alluvial meadow by the side of a stream, and here and there an insulated patch of mossy soil among the hollows of the crags; but, though it might possess its few gardens for the spade, it would have no fields for the plough. We owe our arable land to that geologic agent which, grinding down, as in a mill, the upper layers of the sufface rocks of the kingdom, and then spreading over the eroded strata their own débris, formed the general basis in which the first vegetation took root, and in the course of years composed the vegetable mould. A foundering land under a severe sky, beaten by tempests and lashed by tides, with glaciers half choking up its cheerless valleys, and with countless icebergs brushing its coasts and grating over its shallows, would have seemed a melancholy and hopeless object to human eye, had there been human eyes to look upon it at the time; and yet such seem to have been the  circumstances in which our country was placed by Him who, to 'perform his wonders,'
in order that at the appointed period it might, according to the poet, be a land'Plants his footsteps in the sea,
And rides upon the storm,'
From the boulder-clay there is a natural transition to the boulders themselves, from which the deposit derives its name. These remarkable travelled stones seem, from the old traditions connected with some of them, to have awakened attention and excited wonder at an early period, long ere Geology was known as a science; nor are they without their share of picturesqueness in certain situations. You will perhaps remember how frequently, and with what variety of aspect, Bewick, the greatest of wood-engravers, used to introduce them into the backgrounds of his vignettes. 'A rural scene is never perfect,' says Shenstone, a poet of no very large calibre, but the greatest of landscape gardeners, 'without the addition of some kind of building: I have, however, known,' he adds, 'a scaur of rock in great measure supplying the deficiency.' And the justice of the poet's canon may be often seen exemplified in those more recluse districts of the country which border on the Highlands, and where a huge rock-like boulder, roughened by mosses and lichens, may be seen giving animation and cheerfulness to the wild solitude of a deep forest glade, or to some bosky inflection of bank waving with birch and hazel on the side of some lonely tarn or haunted streamlet. Even on a dark sterile moor, where the pale lichen springs up among the stunted heath, and the hairy club-moss goes creeping among the stones, some vast boulder, rising grey amid the waste, gives to the fatigued eye a reposing point, on which it can rest for a time, and then let itself out on the expanse around. Boulder-stones  stones are still very abundant in Scotland, though for the last century they have been gradually disappearing from the more cultivated tracts where there were fences or farm steadings to be built, or where they obstructed the course of the plough. We find them occurring in every conceivable situation : high on hill-sides, where the shepherd crouches beside them for shelter in a shower; deep in the open sea, where they entangle the nets of the fisherman on his fishing banks; on inland moors, where in some remote age they were laboriously rolled together to form the Druidical circle or Pict's House; or on the margin of the coast, where they had been piled over one another at a later time, as protect ing bulwarks against the waves. They are no longer to be seen in this neighbourhood in what we may term the agri cultural region; but they still occur in great numbers along the coast, within the belt that intervenes between high and low water, and on an upper moorland zone over which the plough has not yet passed. Mr. Charles M'Laren describes, in his admirable little work on The Geology of Fife and the Lothans, a boulder of mica schist weighing from eight to ten tons, which rests, among many others, on one of the Pentland Hills, and which derives an interest from the fact that, as shown by the quality of the rock, the nearest point from which it could have come is at least fifty miles away. A well-known greenstone boulder of still larger size may be seen at the line of half-ebb, about half-way between Leith and Portobello. But though about ten feet in height, it is a small stone, compared with others of its class both in this country and the Continent. The rock, as it is well termed (for it is a mass of granite weighing fifteen hundred tons), on which the colossal statue of Peter the Great at St. Petersburg is placed, is a travelled boulder, which was found dissociated from every other stone of its kind in the middle of a morass; and Sir Roderick Murchison describes, in one of his papers on the Northern Drift, a Scandinavian boulder  thirty feet in height by one hundred and forty in circumference. Most, if not all the boulders which we find in this part of the country on the lower zone have been washed out of the boulder-clay. Wherever we find a group of boulders on the portion of sea-bottom uncovered by the ebb, we have but to look at the line where the surf breaks when the sea is at full, and there we find the clay itself, with its half-uncovered boulders projecting from its yielding sides, apparently as freshly grooved and scratched as if the transporting iceberg had been at work upon them but yesterday.'Made blithe by plough and harrow.'
I must again adduce the evidence of Sir Charles Lyell, to show that masses of this character are frequently ice-borne. 'In the river St. Lawrence,' we find him stating in his Elements, 'the loose ice accumulates on the shoals during the winter, at which season the water is low. The separate fragments of ice are readily frozen together in a climate where the temperature is sometimes thirty degrees below zero, and boulders become entangled with them; so that in spring, when the river rises on the melting of the snow, the ice is floated off, frequently conveying the boulders to great distances. A single block of granite fifteen feet long by ten feet both in breadth and height, and which could not contain less than fifteen hundred cubic feet of stone, was in this way moved down the river several hundred yards, during the late survey in 1837. Heavy anchors of ships lying on the shore have in like manner been closed in and removed. In October 1806 wooden stakes were driven several feet into the ground at one part of the banks of the St. Lawrence at high-water mark, and over them were piled many boulders as large as the urited force of six men could roll. The year after, all the boulders had disappeared, and others had arrived, and the stakes had been drawn out and carried away by the ice.'
Our Scottish boulders, — though in many instances immediately  associated, as in this neighbourhood, with the boulder-clay, and in many others, as in our moorland districts, with the bare rock, — occur in some cases associated with the superficial sands and gravels, and rest upon or over these. And in these last instances they must have been the subjects of a course of ice-borne voyagings subsequent to the earlier course, and when the land was rising. Even during the last sixty years, though our winters are now far from severe, there have been instances in Scotland of the transport of huge stones by the agency of ice; and to two of these, as of a character suited to throw some light on the boulder voyagings of the remote past, I must be permitted to refer.
Some of my audience may have heard of a boulder well known on both sides of the Moray Firth as the 'Travelled Stone of Petty,' — a district which includes the Moor of Culloden, and at whose parish church Hector Boece saw the gigantic bones of the colossal Little John. The Clach dhu n-Aban, or black stone of the white bog, — for such is the graphically descriptive Gaelic name of the moss, — measures about six feet in height by from six to seven feet in breadth and thickness, and served, up to the 19th of February 1799, as a march-stone between the properties of Castle Stuart and Culloden. It lay just within flood-mark, near where a little stream empties itself into a shallow sandy bay. There had been a severe, long-continued frost throughout the early part of the month; and the upper portions of the bay had acquired, mainly through the agency of the streamlet, a continuous covering of ice, that had attained, round the base of the stone, which it clasped fast, a thickness of eighteen inches. On the night of the 19th the tide rose unusually high on the beach, and there broke out a violent hurricane from — the east-south-east, accompanied by a snow storm. There is a meal mill in the immediate neighbourhood of the stone; and when the old miller, — as he related the story to  the late Sir Thomas Dick Lauder, — got up on the morning of the 20th, so violent was the storm, and so huge the snow-wreaths that blocked up every window and door, and rose over the eaves, that he could hardly make his way to his barns, — a journey of but a few yards; and in returning again from them to his dwelling, he narrowly escaped losing himself in the drift. In looking towards the bay, in one of the pauses of the storm, he could scarce credit his eyesight; the immense Clach dhu n-Aban had disappeared, — vanished, — gone clean off the ground; and he called to his wife in astonishment and alarm, that the 'meikle stane was awa.' The honest woman looked out, and then rubbed her eyes, as if to verify their evidence; but the fact was unquestionable, — the 'meikle stane' certainly 'was awa;' and there remained but a hollow pit in the sand, with a long shallow furrow, stretching from the pit outwards to where the snow rhime closed thick over the sea, to mark where it had been. When, however, the weather cleared up, the stone again became visible, lying out in the sands uncovered by the ebb, seven hundred and eighty feet from its former position. In the evening of the day, the neighbours flocked out by scores, to examine the scene of so extraordinary a prodigy. Where the stone had lain they found but the deep dent, connected by the furrow which lay athwart the bay in the line of the hurricane with the stone itself, around the base of which there still projected a thick cornice of ice. In its new posi tion the stone still lies; and only a few years ago, — mayhap still, — a wooden post which marked the point where the two contiguous properties met, marked also the spot from which, after a rest of ages, it had set out on its short voyage.
My other case of boulder travelling, — in some respects a more curious case than the one related, — occurred early in the present century on the eastern coast of Sutherlandshire. Near the small hamlet of Torboll, in the upper part of Loch Fleet, there stood, about fifty years ago, a rude obelisk of  undressed stone, generally regarded as Danish, which, though more ancient than authentic history, or even tradition, in the district, was less so than the old coast line, as it had been evidently erected, subsequent to the last change of level, on the flat marginal strip which intervenes between the old line and the sea. It rose in the middle of a swampy hollow, which protracted rains sometimes converted into a strip of water, and which was sometimes swept by the over flowings of the neighbouring river. On the eve of the incident which proved the terminating one in its history, the hollow, previously filled with rain-water, had been frozen to the bottom by a continued frost, which was, however, on the eve of breaking up; and a dense fog lay thick in the valley, when a benighted Highlander, returning tipsy from a market by the light of the moon, came staggering in the direction of the standing stone, and in a drunken frolic set his bonnet on the top of it; and then, wandering off into the mist, he lost sight of both stone and bonnet, and, failing to regain them, he had to return bareheaded to his home. The thaw came on; the river rose over its banks; the ice-cake around the obelisk floated high above the level, wrenching up the obelisk along with it, as the ice of the St. Lawrence wrenched up the stakes described by Sir Charles Lyell ; and both ice-cake and obelisk floated down the loch to the sea. As the morning broke, — a fierce morning of flood and tempest, — they were seen passing what some forty years ago was known as the Little Ferry; and the alarm went abroad along the shores on both sides, that there was a man standing in the middle of the Loch on the floating ice, and in course of being swept out to the ocean. Poor man! he had been crossing the river, it was inferred, when the ice broke up; and though the enterprise was a somewhat perilous one, for the ice fragments were rushing furiously along on the wild tides of the loch, maddened by the inundation, a boat, double manned, shot out from the shore to the rescue,  and soon neared the drifting ice-floe. It was ultimately seen, however, that the supposed man was but the Danish obelisk, bearing on its head a mysterious bonnet; and bonnet and obelisk were left to find their way to the German Ocean, in which it is probable they now both lie. These modern instances of boulder travelling may serve to show how huge stones originally associated with the boulder-clay may have come to rest on the arenaceous or gravelly deposits which overlie it. Through the second voyage of the Petty boulder, it was deposited on a recently formed bed of sand; and the standing-stone of Torboll may now rest on sea-shells that were living half a century ago.
It is held by geologists of high standing, that after the period of submergence represented by the boulder-clays of our country, the British islands were elevated to such a height over the sea-level, that their distinctive character as islands was lost, and the area which they occupy united to the main land in the character of a western prolongation of, the great European continent. It was at this period, says Professor Edward Forbes, that Britain and Ireland received, over the upraised bed of the German Ocean, their Germanic flora, — the last acquired of the five floras which compose their vegetation. The evidence on the point, however, still seems somewhat meagre. I can have no doubt that the land stood considerably higher during this Post-Tertiary period than it does now. As shown by the dressed surfaces and rounded forms of many of the smaller islets of the north-western coasts of Scotland, and the markings at the bottom of its lochs and estuaries, and on the rocks along their shores, the latter glaciers must have descended from the central hills of the country far below the present sea-level; and we find some of the transverse moraines which they ploughed up before them in their descent existing as gravelly spits, that rise amid the waves, in the middle of long firths or at the entrance of deep bays. I have seen, too, on rocky coasts,  considerably below the tide-line at flood, a sort of recent breccia formed by calcareous springs, which, as the stalagmitical matter could not have been deposited in places exposed to the diurnal washings of the sea, indicated a higher level of the land than now, at the time of its formation; and the submerged mosses of both Britain and Ireland, — mosses now existing in many localities far below the fall of the tide, — where not more ancient than the boulder-clay, bear evidence in the same line. But on this obscure passage in the geological history of our country I am unable, from at least actual observation, to say aught more: my few facts lie in the direction of Professor Forbes's theory, but they accompany it only a short way. There is a wide gap still unfilled. I may be permitted to remind you, that it is held by the Professor, — one of the most accomplished of our geologists, — that of the five British floras, we have two in Scotland, — the Germanic flora, and the semi-arctic or Scandinavian flora; that these were introduced into the country at diffeient periods; and that while the Germanic flora dates from the times of the Post-Tertiary elevation of the land, the more ancient of the two — the semi-arctic or Scandinavian — dates from the preceding times of the boulder-clay. Nor does it appear in any degree more improbable that we should have the descendants of the plants of even the remoter period still vital on our hill tops, than that we should have the descendants of some of its animals still living in our seas. It seems at first a curious problem, difficult of solution, that widely separated mountain summits should possess the same alpine plants, — that the summits of Ben Wyvis and Ben Lomond, for instance, or of Ben Nevis and Ben Muich Dhui, should have their species in common, while not a trace of them appears on the lower elevations between. But it simplifies the case to conceive of these alpine plants as the vegetable aborigines of the country, compelled by climatal invasion to shelter in  its last bleak retreats, where the winter snows linger unwasted till midsummer, and the breeze is always laden with the chills of the old glacial period. They compose the Celtic portion of the Scottish flora, cooped up in their mountain recesses by the encroachments of those Germanic races of the plant family that flourish, in the altered atmosphere, on the more genial plains of the country, or on the sunny slopes of its lower hills. That language of flowers in which the ladies of Mohammedan countries have learned to converse is not unappropriately employed in giving expression to the various modes of a passion scarce less evanescent than the flowers themselves. But is it not passing strange, that we of Scotland should be called on to recognise in the transitory flowers of our sheltered low-lying plains and valleys, and of our high bleak moors and exposed mountain summits, the records of an antiquity so remote, that the stories told by the half-effaced hieroglyphics of Nineveh and of Egypt are of yesterday in comparison?
Here the exhibition of our facts illustrative of the Pleistocene and Post-Tertiary periods in Scotland properly ends. The existing evidence has been taken, though, of course, briefly and imperfectly, the extent and multiplicity of the subject considered; and, the record closed, a formal summary of the conclusions founded upon it should now terminate our history. Permit me, however, to present you, in conclusion, not with the formal summary, but a some what extended picture, of the whole, exhibited, panorama-like, as a series of scenes. The fine passage in the Autumn of Thomson, in which the poet lays all Scotland at once upon the canvas, and surveys it at a glance, must be familiar to you all —
Let us in like manner attempt calling up the features of our country in one continuous landscape, as they appeared at the commencement of the glacial period, just as the paroxysm of depression had come on, and bold headland and steep iron-bound islet had begun slowly to settle into the sea.'Here awhile the Muse,
High hovering o'er the broad cerulean scene,
Sees Caledonia in romantic view;
Her airy mountains, from the waving main, 
Invested with a keen diffusive sky,
Breathing the soul acute; her forests huge,
Incult, robust, and tall, by Nature's hand
Planted of old; her azure lakes between,
Pour'd out extensive, and of watery wealth
Full; winding deep and green, her fertile vales,
With many a cool, translucent, brimming flood
Wash'd lovely, from the Tweed (pure parent stream,
Whose pastoral banks first heard my Doric reed,
With, sylvan Jed, thy tributary brook),
To where the North's inflated tempest foams
O'er Orcas or Betubium's highest peak.'
The general outline is that of Scotland, though harsher and more rugged than now, for it lacks the softening integument of the subsoils. Yonder are the Grampians, and yonder the Cheviots, and, deeply indenting the shores, yonder are the well-known estuaries and bays, — the firths of Forth, Tay, and Moray, and the long withdrawing lakes, Loch Katrine, and Loch Awe, and Loch Maree, and the far-gleaming waters of the deep Caledonian Valley, the Ness, and the Oich, and the Lochy. But though the summer sun looks down upon the scene, the snow-line descends beneath the top of even our second-class mountains; and the tall beetling Ben Nevis, and graceful Ben Lomond, and the broad-based Ben Mtiich Dhui, glitter in the sunshine, in their coats of dazzling white, from their summits half-way down to their bases. There are extended forests of the native fir on the lower plains, mingled with the slimmer forms and more richly-tinted foliage of the spruce pine. On the upper grounds, thickets of stunted willows and straggling  belts of diminutive birches skirt the ravines and water-courses, and yellow mosses and grey lichens form the staple covering of the humbler hill-sides and the moors. But the distinctive feature of the country is its glaciers. Fed by the perpetual snows of the upper heights, the deeper valleys among the mountains have their rigid ice-rivers, that in the narrower firths and lochs of the western and northern coasts shoot far out, mole-like, into the tide. And, lo! along the shores, in sounds and bays never yet ploughed by the keel of voyager, vast groups of icebergs, that gleam white to the sun, like the sails of distant fleets, lie moveless in the calm, or drift slowly along in rippling tideways. Nor is the land without its inhabitants, though man has not yet appeared. The colossal elephant, not naked and dingy of coat, like his congener of the tropics, but shaggy, with long red hair, browses among the woods. There is a strong-limbed rhinoceros wallowing in yonder swamp, and a herd of rein-deer cropping the moss high on the hill-side beyond. The morse is basking on that half-tide skerry; and a wolf, swept seawards by the current, howls loud in terror from yonder drifting ice-floe. We have looked abroad on our future country in the period of the first local glaciers, ere the submergence of the land.
Ages pass, and usher in the succeeding period of the boulder-clay. The prospect, no longer that of a continuous land, presents us with a wintry archipelago of islands, broken into three groups by two deep ocean-sounds, — the ocean-sound of the great Caledonian Valley, and that of the broader but shallower valley which stretches across the island from the Clyde to the Forth. We stand full in front of one of these vast ocean-rivers, — the southern one. There are snow-enwrapped islets on either side. Can yonder thickly-set cluster be the half-submerged Pentlands? and yonder pair of islets, connected by a low flat neck, the eastern and western Lomonds? and yonder half-tide rock,  blackened with algae, and around which a shoal of porpoises are gambolling, the summit of Arthur Seat? The wide sound, now a rich agricultural valley, is here studded by its fleets of tall icebergs, — there cumbered by its level fields of drift-ice. Nature sports wantonly amid every variety of form; and the motion of the great floating masses, cast into shapes with which we associate moveless solidity, adds to the magical effect of the scene. Here a flat-roofed temple, surrounded by colonnades of hoar and wasted columns, comes drifting past; there a cathedral, furnished with towers and spire, strikes heavily against the rocky bottom, many fathoms beneath, and its nodding pinnacles stoop at every blow. Yonder, already fast aground, there rests a ponderous castle, with its curtained towers, its arched gateway, and its multi tudinous turrets, reflected on the calm surface beneath; and pyramids and obelisks, buttressed ramparts, and em brasured watch-towers, with shapes still more fantastic, — those of ships, and trees, and brute and human forms, — crowd the retiring vista beyond. There is a scarce less marked variety of colour. The intense white of the field- ice, thinly covered with snow, and glittering without shade in the declining sun, dazzles the eye. The taller icebergs gleam in hues of more softened radiance, — here of an emerald green, there of a sapphire blue, yonder of a paly marble grey; the light, polarized by a thousand cross re flections, sports amid the planes and facets, the fissures and pinnacles, in all the rainbow gorgeousness of the prismatic hues. And bright over all rise on the distant horizon the detached mountain-tops, now catching a flush of crimson and gold from the setting luminary. But the sun sinks, and the clouds gather, and the night comes on black with tempest; and the grounded masses, moved by the violence of the aroused winds, grate heavily along the bottom; and while the whole heavens are foul with sleet and snow-rack, and the driving masses clash in rude collision, till all beneath  is one wide stunning roar, the tortured sea boils and dashes around them, turbid with the comminuted débris of the fretted rocks below.
The vision belongs to an early age of the boulder-clay: it changes to a later time; and the same sea spreads out as before, laden by what seem the same drifting ice-floes. But the lower hills, buried in the profound depths of ocean, are no longer visible; the Lammermuirs have disappeared; and the slopes of Braid and Duddingstone, with
and we can only determine their place by the huger icebergs that lie stranded and motionless on their peaks; while the lesser masses drift on to the east. Moons wax and wane, and tides rise and fall; and still the deep current of the gulf-stream flows ever from the west, traversing the wide Atlantic, like some vast river winding through an enormous extent of meadow; and, in eddying over the submerged land, it arranges behind the buried eminences, in its own easterly line, many a long trail of gravel and débris, to form the Crag and Tail phenomenon of future geologists. As we extend our view, we may mark, far in the west, where the arctic current, dotted white with its ice-mountains and floes, impinges on the gulf stream; and where, sinking from its chill density to a lower stratum of sea, it gives up its burden to the lighter and more tepid tide. A thick fog hangs over the junction, where the warmer waters of the west and south encounter the chill icy air of the north; and, steaming forth into the bleak atmosphere like a seething caldron, the cloud, when the west wind blows, fills with its thick grey reek the recesses of the half-foundered land, and obscures the prospect."North Berwick Law, with cone of green,
And Bass amid the waters;"
Anon there is another change in the dream. The long period of submergence is past; the country is again rising; and, under a climate still ungenial and severe, the glaciers  lengthen out seawards, as the land broadens and extends, till the northern and western Highlands seem manacled in ice. Even the lower hill-tops exhibit an alpine vegetation, beautiful, though somewhat meagre; while in the firths and bays, the remote ancestors of many of our existing shells that thrive in the higher latitudes, still mix, as at an earlier period, with shells whose living representatives are now to be sought on the coasts of northern Scandinavia and Greenland. Ages pass; the land rises slowly over the deep, terrace above terrace; the thermal line moves gradually to the north; the line of perpetual snow ascends beyond the mountain summits; the temperature increases; the ice disappears; the semi-arctic plants creep up the hill-sides, to be supplanted on the plains by the leafy denizens of happier climates; and at length, under skies such as now look down upon us, and on nearly the existing breadth of land, the human period begins. The half-naked hunter, armed with his hatchet or lance of stone, pursues the roe or the wild ox through woods that, though comparatively but of yesterday, already present appearances of a hoar antiquity; or, when the winter snows gather around his dwelling, does battle at its beleaguered threshold with the hungry wolf or the bear. The last great geologic change takes place; the coast line is suddenly elevated; and the country presents a new front to the sea. And on the widened platform, when yet other ages have come and gone, the historic period commences, and the light of a classical literature falls for the first time on the incidents of Scottish story, and on the bold features of Scottish character.
It is said that modern science is adverse to the exercise and development of the imaginative faculty. But is it really so? Are visions such as those in which we have been indulging less richly charged with that poetic pabulum on which fancy feeds and grows strong, than those ancient tales of enchantment and faery which beguiled of old, in  solitary homesteads, the long winter nights. Because science flourishes, must poesy decline? The complaint serves but to betray the weakness of the class who urge it. True, in an age like the present, — considerably more scientific than poetical, — science substitutes for the smaller poetry of fiction, the great poetry of truth; and as there is a more general interest felt in new revelations of what God has wrought, than in exhibitions of what the humbler order of poets have half-borrowed, half-invented, the disappointed dreamers complain that the 'material laws' of science have pushed them from their place. As well might the Arab who prided himself upon the beauty of some white tent which he had reared in some green oasis of the desert, complain of the dull tools of Belzoni's labourers, when engaged in clearing from the sands the front of some august temple of the ancient time. It is not the tools, it might be well said to the complainer, that are competing with your neat little tent; it is the sublime edifice, hitherto covered up, which the tools are laying bare. Nor is it the material laws, we may, on the same principle, say to the poets of the querulous cast, that are overbearing your little inventions, and making them seem small; but those sublime works and wonderful actings of the Creator which they unveil, and bring into comparison with yours. But from His works and His actings have the masters of the lyre ever derived their choicest materials; and whenever a truly great poet arises, — one that will add a profound intellect to a powerful imagination, — he will find science not his enemy, but an obsequious caterer and a devoted friend. He will find sermons in stones, and more of the suggestive and the sublime in a few broken scaurs of clay, a few fragmentary shells, and a few green reaches of the old coast line, than versifiers of the ordinary calibre in their once fresh gems and flowers, — in sublime ocean, the broad earth, or the blue firmament and all its stars.