FOOTNOTES:

'Chases round and roundThe hoary beard of thistle old,Dark-moving over grassy mounds.'[45]

'Chases round and round

The hoary beard of thistle old,

Dark-moving over grassy mounds.'[45]

We mark the graves of dead heroes by

'Their long grass waving in the wind,'

and we move onwards 'in the robe of the misty glen' past

'Branches and brown tufts of grassWhich tremble and whistle in the breeze.'

'Branches and brown tufts of grass

Which tremble and whistle in the breeze.'

But when the full Atlantic gale sweeps over the land, and the rain-clouds rush in swift procession across thehalf-hidden hills, the moaning and shrieking of the storm come like sounds from another world. We seem to hear the tread, and almost to see the forms, of the ghosts of the Ossianic heroes,

'Chasing spectre-boars of mistOn wings of great winds on the cairn.When bursts the cloud in Cona of the glens,A thousand spirits wildly shriekOn the waste wind that sweeps around the cairn.'

'Chasing spectre-boars of mist

On wings of great winds on the cairn.

When bursts the cloud in Cona of the glens,

A thousand spirits wildly shriek

On the waste wind that sweeps around the cairn.'

Nor is the turmoil of the tempest on the sea less vividly depicted. We are shown the

'Waves surging onward in mist,When their crests are seen in foamOver smoke and haze widespread.'

'Waves surging onward in mist,

When their crests are seen in foam

Over smoke and haze widespread.'

In the midst of the gloom we descry a shore-stack against which the ocean

'Dashes the force of billows cold;White spray is high around its throat,And cairns resound on the heathery steep.'

'Dashes the force of billows cold;

White spray is high around its throat,

And cairns resound on the heathery steep.'

With these pictures of tumult on land and sea, there come glimpses of those cherished interludes of bright sunshine, when the western hills and firths are seen at their loveliest. But whether radiant or gloomy the landscape is in unison with the human emotion described—

'Pleasing the tale of the time which has gone;Soothing as noiseless dew of morning mild,On the brake and knoll of roes,When slowly rises the sunOn the silent flank of hoary Bens—The loch, unruffled, far away,Calm and blue on the floor of the glens.'[46]

'Pleasing the tale of the time which has gone;

Soothing as noiseless dew of morning mild,

On the brake and knoll of roes,

When slowly rises the sun

On the silent flank of hoary Bens—

The loch, unruffled, far away,

Calm and blue on the floor of the glens.'[46]

As a final sample of the Ossianic landscape, with its kaleidoscopic play of atmospheric effect, answering to the changes of human feeling, let me cite some lines fromFingal:—

'Morna, most lovely among women,Why by thyself in the circle of stones,In hollow of the rock on the hill alone?Rivers are sounding around thee;The aged tree is moaning in the wind;Turmoil is on yonder loch;Clouds darken round the tops of Cairns [mountains];Thyself art like snow on the hill—Thy waving hair like mist of Cromla,Curling upward on the Ben,'Neath gleaming of the sun from the west;Thy soft bosom like the white rockOn bank of Brano of white streams.'[47]

'Morna, most lovely among women,

Why by thyself in the circle of stones,

In hollow of the rock on the hill alone?

Rivers are sounding around thee;

The aged tree is moaning in the wind;

Turmoil is on yonder loch;

Clouds darken round the tops of Cairns [mountains];

Thyself art like snow on the hill—

Thy waving hair like mist of Cromla,

Curling upward on the Ben,

'Neath gleaming of the sun from the west;

Thy soft bosom like the white rock

On bank of Brano of white streams.'[47]

Though Macpherson roused the interest of the world in the rugged scenery and boisterous climates of the west, it was some time before any other writer followed his lead among the highlands of this country. It is singular to reflect that though the mountain-world, more than any other part of the land, appeals to the imagination, by revealing all that is most impressive in form and colour, and all that is most vigorous in the elemental warfare of nature, it was the last part of the terrestrial surface to meet with due appreciation. Little more than a century has passed since men began to visit the Scottish Highlands for the pleasure of admiring their scenery. Previous to the suppression of the Jacobite rising, that mountainous region was regarded as the abode of a half-savage race, into whosewilds few lowlanders would venture without the most urgent reasons. Even after military roads had been made across it, the accommodation for travellers was still generally of the most wretched kind. Those who had occasion to traverse it gave such an account of their experiences as one would hardly now expect to receive from the heart of Africa.[48]The poet Gray during his visit to Scotland in the year 1765, made a brief excursion into the Perthshire Highlands, and, in spite of the discomforts of travel at that time, came away with a vivid impression of the grandeur and beauty of the scenery. But the only record that remains of this impression is to be found in a few sentences in his letters.[49]

Eight years after Gray's visit, Samuel Johnson in 1773 made his more adventurous journey to the Hebrides. When we consider what were the discomforts, and sometimes the actual dangers which he had to undergo, we cannot but admire the quiet courage with which he endured them, and the reticence with which he refers to them in his narrative. But Johnson could see no charm in the Highland mountains. In his poem on London he had asked many years before:

'For who would leave, unbrib'd, Hibernia's land,Or change the rocks of Scotland for the Strand?'

'For who would leave, unbrib'd, Hibernia's land,

Or change the rocks of Scotland for the Strand?'

Yet when at last he set foot in Scotland, he showed no disposition to prefer its rocks to his haunts in London. Travelling through some of the finest scenery in Western Inverness-shire, this is the language he uses regarding it: 'The hills exhibit very little variety; being almost wholly covered with dark heath, and even that seems to be checked in its growth. What is not heath is nakedness, a little diversified by now and then a stream rushing down the steep. An eye accustomed to flowery pastures and waving harvests is astonished and repelled by this wide extent of hopeless sterility. The appearance is thatof matter incapable of form or usefulness, dismissed by nature from her care and disinherited of her favours, left in its original elemental state, or quickened only by one sullen power of useless vegetation.'[50]

While such was the attitude of the man of letters in this country, influences were at work on the Continent which powerfully affected the relations of literature to the whole realm of outer nature, and more especially to mountain-scenery. Rousseau's descriptions, followed by the more detailed and scientific narrative of De Saussure, drew the attention of society to the fascinations of Switzerland and the Alps. But these influences had hardly had time to exert much sway in their application to the scenery of our own country when the genius of Scott suddenly brought the features of the Scottish Highlands into the most popular literature of his day. In his youth the future poet and novelist had paid some visits to the glens and lakes of Perthshire, where he found many a primitive custom still remaining, which has since vanished before roads, railways, and tourists. In the year 1810 hisLady of the Lakeappeared. Thenceforward the stream of summer visitors set in, which has poured in an ever-increasing flood into the Highlands of Scotland. The general interest thus awakened in the glens and mountains of the north was still further intensified by the advent of theLord of the Isles, and ofWaverley,Rob Roy, and the other novels that depict scenes in the Highlands. Certainly no man ever did so much as Walter Scott to make the natural features of his native country familiar to the whole world.The literary charm which he threw over the hills and glens of Perthshire kindled a wide-spread enthusiasm for the more rugged aspects of nature, and gave a powerful stimulus to the slowly-growing appreciation of the beauty and grandeur of mountain-scenery.

Nevertheless it must be admitted that Scott's highland landscapes, though more prominent and detailed than those in his descriptions of the lowlands and uplands, were also more laboured and less spontaneous. His pictures are no doubt faithful and graphic, and each of them leaves on the mind a clear impression of the scene depicted. But their effect is produced rather by a multiplicity of touches than by a few masterstrokes of poetic insight and graphic delineation. Moreover they are all in one tone of colour, and lack that changeful diversity so characteristic of mountains. They are chiefly fine-weather portraits, as if the poet loved only summer sunshine among the hills, and had either never seen or cared not to portray their gloom, cloud, and storm. We are bound of course to remember that, after all, he was only an occasional visitor to the Highlands. He had not been born among them, and never lived long enough in their solitudes to become intimately versed in all their alternations of mood under changes of sky and season. He writes of them as an admiring and even enthusiastic spectator, but not as one into whose very soul the power of the mountains had entered. He never warms among them into that fervent glow of affectionate appreciation which kindles within him in sight of the landscapes of his native Border.

One other mountainous district in Britain—that of the English Lakes—claims our attention for its influence on the progress of the national literature. Of all the isolated tracts of higher ground in these islands, that of the Lake District is the most eminently highland in character. It is divisible into two entirely distinct portions by a line drawn in a north-easterly direction from Duddon Sands to Shap Fells. South of that line the hills are comparatively low and featureless, though they enclose the largest of the lakes. They are there built up of ancient sedimentary strata, like those that form so much of the similar scenery in the uplands of Wales and the South of Scotland. But to the north of the line, most of the rocks are of a different nature, and have given rise to a totally distinct character of landscape. They consist of various volcanic materials which in early Palaeozoic time were piled up around submarine vents, and accumulated over the sea-floor to a thickness of many thousand feet. They were subsequently buried under the sediments that lie to the south, but, in after ages uplifted into land, their now diversified topography has been carved out of them by the meteoric agents of denudation. Thus pike and fell, crag and scar, mere and dale, owe their several forms to the varied degrees of resistance to the general waste offered by the ancient lavas and ashes. The upheaval of the district seems to have produced a dome-shaped elevation, culminating in a summit that lay somewhere between Helvellyn and Grasmere. At least from that centre the several dales diverge, like the ribs from the top of a half-opened umbrella.

The mountainous tract of the Lakes, though it measures only some thirty-two miles from west to east by twenty-three from north to south, rises to heights of more than 3,000 feet, and as it springs almost directly from the margin of the Irish Sea, it loses none of the full effect of its elevation. Its fells present a thoroughly highland type of scenery, and have much of the dignity of far loftier mountains. Their sky-line often displays notched crests and rocky peaks, while their craggy sides have been carved into dark cliff-girt recesses, often filled with tarns, and into precipitous scars, which send long trails of purple scree down the grassy slopes.

Moreover, a mild climate and copious rainfall have tempered this natural asperity of surface by spreading over the lower parts of the fells and the bottoms of the dales a greener mantle than is to be seen among the mountains further north. Though the naked rock abundantly shows itself, it has been so widely draped with herbage and woodland as to combine the luxuriance of the lowlands with the near neighbourhood of bare cliff and craggy scar.

Such was the scenery amidst which William Wordsworth was born and spent most of his long life. Thence he drew the inspiration which did so much to quicken the English poetry of the nineteenth century, and which has given to his dales and hills so cherished a place in our literature. The scenes familiar to him from infancy were loved by him to the end with an ardent and grateful affection which he never wearied of publishing to the world. No mountain-landscapes had ever before been drawn so fully, so accurately, andin such felicitous language. Every lineament of his hills and dales is depicted as luminously and faithfully in his verse as it is reflected on the placid surface of his beloved meres, but suffused by him with an ethereal glow of human sympathy. He drew from his mountain-landscape everything that

'Can give an inward help, can purifyAnd elevate, and harmonize and soothe.'

'Can give an inward help, can purify

And elevate, and harmonize and soothe.'

It brought to him 'authentic tidings of invisible things'; and filled him with

'The senseOf majesty and beauty and repose,A blended holiness of earth and sky.'

'The sense

Of majesty and beauty and repose,

A blended holiness of earth and sky.'

For his obligations to that native scenery he found continual expression.

'Ye mountains and ye lakes,And sounding cataracts, ye mists and windsThat dwell among the hills where I was born,If in my youth I have been pure in heart,If, mingling with the world, I am contentWith my own modest pleasures, and have livedWith God and Nature communing, removedFrom little enmities and low desires—The gift is yours.'

'Ye mountains and ye lakes,

And sounding cataracts, ye mists and winds

That dwell among the hills where I was born,

If in my youth I have been pure in heart,

If, mingling with the world, I am content

With my own modest pleasures, and have lived

With God and Nature communing, removed

From little enmities and low desires—

The gift is yours.'

Not only did his observant eye catch each variety of form, each passing tint of colour on his hills and valleys, he felt, as no poet before his time had done, the might and majesty of the forces by which, in the mountain-world, we are shown how the surface of the world is continually modified.

'To him was givenFull many a glimpse of Nature's processesUpon the exalted hills.'

'To him was given

Full many a glimpse of Nature's processes

Upon the exalted hills.'

The thought of these glimpses led to one of the noblest outbursts in the whole range of his poetry, where he gives way to the exuberance of his delight in feeling himself, to use Byron's expression, 'a portion of the tempest'—

'To roam at large among unpeopled glensAnd mountainous retirements, only trodBy devious footsteps; regions consecrateTo oldest time; and reckless of the storm,. . . . . while the mistsFlying, and rainy vapours, call out shapesAnd phantoms from the crags and solid earth,. . . . . and while the streamsDescending from the region of the clouds,And starting from the hollows of the earth,More multitudinous every moment, rendTheir way before them—what a joy to roamAn equal among mightiest energies!'

'To roam at large among unpeopled glens

And mountainous retirements, only trod

By devious footsteps; regions consecrate

To oldest time; and reckless of the storm,

. . . . . while the mists

Flying, and rainy vapours, call out shapes

And phantoms from the crags and solid earth,

. . . . . and while the streams

Descending from the region of the clouds,

And starting from the hollows of the earth,

More multitudinous every moment, rend

Their way before them—what a joy to roam

An equal among mightiest energies!'

In this passage Wordsworth seems to have had what he would have called 'a foretaste, a dim earnest' of that marvellous enlargement of the charm and interest of scenery due to the progress of modern science. When he speaks of 'regions consecrate to oldest time,' he has a vague feeling that somehow his glens and mountains belonged to a hoary antiquity, such as could be claimed by none of the verdant plains around. Had he written half a century later he would have enjoyed a clearer perception of the vastness of that antiquity and of the long succession of events with which it was crowded.[51]

It is curious to remember that three of the poets whom I have singled out as illustrations of the influence of our lowland, upland, and highland scenery upon our literature have held up the geologist to ridicule. Cowper put that votary of science into the pillory among the irreligious crowd, about whose ears the poet loved to 'crack the satiric thong.'[52]Wordsworth treated the geological enthusiast with withering scorn.[53]Scott, with characteristic good humour, only poked fun at him.[54]It was reserved for a poet of our own day to look below the technical jargon of the schools, and to descry something of this wealthof new interest which the landscape derives from a knowledge of the history of its several parts. But Tennyson only entered a little way into this enlarged conception of nature. There remains a boundless field for some future poetic seer, who letting his vision pierce into the past, will set before the eyes of men the inner meaning of mountain and glen.

And thus, while we recognise the potent influence which the scenery of the country has exerted on the progress of our literature, we can look forward to a fresh extension of this influence as the outcome of geological investigation. Already the result of this widening of the outlook has made itself felt alike in prose and verse. The terrestrial revolutions of which each hill and dale is a witness; the contrasts presented between the present aspect and past history of every crag and peak; the slow, silent sculpturing that has carved out all this marvellous array of mountain-forms—appeal vividly to the imagination, and furnish themes that well deserve poetic treatment. That they will be seized upon by some Wordsworth of the future, I cannot doubt. The bond between landscape and literature will thus be drawn closer than ever. Men will be taught that beneath and behind all the outward beauty of our lowlands, our uplands, and our highlands there lies an inner history which, when revealed, will give to that beauty a fuller significance and an added charm.

FOOTNOTES:[20]Types of Scenery and Their Influence on Literature, the Romanes Lecture, delivered in the Sheldonian Theatre, Oxford, June 1, 1898.[21]See the preceding essay for a fuller discussion of this part of the subject.[22]See p. 24.[23]The Task, bk. i. 154-176.[24]Ibid., i. 177.[25]The Task, iii. 357.[26]Ibid., iv. 246.[27]Ibid., vi. 112.[28]Winter, 8.[29]Summer, 192.[30]Ibid., 89.[31]Autumn, 476.[32]Spring, 381, 400, 402;Summer, 13.[33]Autumn, 337.[34]To William Simpson, stanza 15.[35]Elegy on Captain Matthew Henderson.[36]Poem on Pastoral Poetry.[37]Winter, a Dirge.[38]A Winter Night.[39]The gloomy night is gathering fast.[40]To Mary in Heaven.[41]This was remarked by Wordsworth in the prefatory note to his lines on Mossgiel.[42]The Vision.[43]Scott was familiar with this natural trait. '"That's the Forth," said the Bailie, with an air of reverence, which I have observed the Scotch usually pay to their distinguished rivers. The Clyde, the Tweed, the Forth, the Spey, are usually named by those who dwell on their banks with a sort of respect and pride, and I have known duels occasioned by any word of disparagement.'—Rob Roy, vol. ii., chap. xi.[44]Arnold,On the Study of Celtic Literature, 1867, p. 152.[45]The quotations here given are from Dr. Clerk's translation of Macpherson's Gaelic version of the Poems. The question has been much disputed whether his English or Gaelic is the original. There can be no doubt that, on the whole, the Gaelic shows greater vividness and accuracy in the description of landscape than the more vague and bombastic English of Macpherson. Dr. Clerk, who has given a literal rendering of the Gaelic line for line, remarks: 'I believe that a careful analysis would resolve very much of Ossian's most weird imagery into idealised representations of the ever-varying and truly wonderful aspects of cloud and mist, of sea and mountain, which may be seen by every observant eye in the Highlands, and it is no fancy to say that the perusal of these poems, as we have them, may be well illustrated by travelling a range of the Highland mountains.'—Poems of Ossian, Dissertation, vol. i. p. lxv.[46]Fingal, iii. 3.[47]Fingal, i. 211.[48]In Burt'sLetters, which give so graphic a picture of the condition of the Highlands of Scotland between the two risings of 1715 and 1745, the general impression made at that time on the mind of an intelligent stranger by the scenery of the region may be gathered from the following quotations: 'I shall soon conclude this description of the outward appearance of the mountains, which I am already tired of, as a disagreeable subject.... There is not much variety, but gloomy spaces, different rocks, heath, and high and low, ... the whole of a dismal gloomy brown drawing upon a dirty purple; and most of all disagreeable when the heath is in bloom. But of all the views, I think the most horrid is, to look at the hills from east to west, orvice versa; for then the eye penetrates far among them, and sees more particularly their stupendous bulk, frightful irregularity, and horrid gloom, made yet more sombrous by the shades and faint reflections they communicate one to another.'—Letters from a Gentleman in the North of Scotland to his Friend in London.Fifth edit., vol. i. p. 285.[49]In writing to Mason he says: 'I am returned from Scotland charmed with my expedition: it is of the Highlands I speak; the Lowlands are worth seeing once, but the mountains are ecstatic, and ought to be visited in pilgrimage once a year. None but those monstrous creatures of God know how to join so much beauty with so much horror. A fig for your poets, painters, gardeners, and clergymen, that have not been among them, their imagination can be made up of nothing but bowling-greens, flowering shrubs, horse-ponds, Fleet ditches, shell-grottoes, and Chinese rails. Then I had so beautiful an autumn; Italy could hardly produce a nobler scene, and this so sweetly contrasted with that perfection of nastiness and total want of accommodation, that Scotland only can supply.'—Gray'sWorks, edit. E. Gosse, vol. iii. p. 223.[50]Journey to the Western Islands of Scotland, 1775, p. 84.[51]Sedgwick did his best to enlighten the poet by his famousFour Letters on the Geology of the Lake District; but these came too late. They were published at Kendal in 1846, and Wordsworth died in 1850.[52]Some drill and boreThe solid earth, and from the strata thereExtract a register, by which we learn,That He who made it, and revealed its dateTo Moses, was mistaken in its age.—The Task, bk. iii. 150.[53]You may trace him oftBy scars which his activity has leftBeside our roads and pathways, though, thank Heaven,This covert nook reports not of his hand—He who with pocket-hammer smites the edgeOf luckless rock or prominent stone, disguisedIn weather-stains or crusted o'er by NatureWith her first growths, detaching by the strokeA chip or splinter—to resolve his doubts:And, with that ready answer satisfied,The substance classes by some barbarous name,And hurries on; or from the fragments picksHis specimen, if but haply interveinedWith sparkling mineral, or should crystal cubeLurk in its cells—and thinks himself enriched,Wealthier, and doubtless wiser, than before!The Excursion, bk. iii.[54]St. Ronan's Well, chap. ii. The passage is quoted postea p. 166.

[20]Types of Scenery and Their Influence on Literature, the Romanes Lecture, delivered in the Sheldonian Theatre, Oxford, June 1, 1898.

[21]See the preceding essay for a fuller discussion of this part of the subject.

[22]See p. 24.

[23]The Task, bk. i. 154-176.

[24]Ibid., i. 177.

[25]The Task, iii. 357.

[26]Ibid., iv. 246.

[27]Ibid., vi. 112.

[28]Winter, 8.

[29]Summer, 192.

[30]Ibid., 89.

[31]Autumn, 476.

[32]Spring, 381, 400, 402;Summer, 13.

[33]Autumn, 337.

[34]To William Simpson, stanza 15.

[35]Elegy on Captain Matthew Henderson.

[36]Poem on Pastoral Poetry.

[37]Winter, a Dirge.

[38]A Winter Night.

[39]The gloomy night is gathering fast.

[40]To Mary in Heaven.

[41]This was remarked by Wordsworth in the prefatory note to his lines on Mossgiel.

[42]The Vision.

[43]Scott was familiar with this natural trait. '"That's the Forth," said the Bailie, with an air of reverence, which I have observed the Scotch usually pay to their distinguished rivers. The Clyde, the Tweed, the Forth, the Spey, are usually named by those who dwell on their banks with a sort of respect and pride, and I have known duels occasioned by any word of disparagement.'—Rob Roy, vol. ii., chap. xi.

[44]Arnold,On the Study of Celtic Literature, 1867, p. 152.

[45]The quotations here given are from Dr. Clerk's translation of Macpherson's Gaelic version of the Poems. The question has been much disputed whether his English or Gaelic is the original. There can be no doubt that, on the whole, the Gaelic shows greater vividness and accuracy in the description of landscape than the more vague and bombastic English of Macpherson. Dr. Clerk, who has given a literal rendering of the Gaelic line for line, remarks: 'I believe that a careful analysis would resolve very much of Ossian's most weird imagery into idealised representations of the ever-varying and truly wonderful aspects of cloud and mist, of sea and mountain, which may be seen by every observant eye in the Highlands, and it is no fancy to say that the perusal of these poems, as we have them, may be well illustrated by travelling a range of the Highland mountains.'—Poems of Ossian, Dissertation, vol. i. p. lxv.

[46]Fingal, iii. 3.

[47]Fingal, i. 211.

[48]In Burt'sLetters, which give so graphic a picture of the condition of the Highlands of Scotland between the two risings of 1715 and 1745, the general impression made at that time on the mind of an intelligent stranger by the scenery of the region may be gathered from the following quotations: 'I shall soon conclude this description of the outward appearance of the mountains, which I am already tired of, as a disagreeable subject.... There is not much variety, but gloomy spaces, different rocks, heath, and high and low, ... the whole of a dismal gloomy brown drawing upon a dirty purple; and most of all disagreeable when the heath is in bloom. But of all the views, I think the most horrid is, to look at the hills from east to west, orvice versa; for then the eye penetrates far among them, and sees more particularly their stupendous bulk, frightful irregularity, and horrid gloom, made yet more sombrous by the shades and faint reflections they communicate one to another.'—Letters from a Gentleman in the North of Scotland to his Friend in London.Fifth edit., vol. i. p. 285.

[49]In writing to Mason he says: 'I am returned from Scotland charmed with my expedition: it is of the Highlands I speak; the Lowlands are worth seeing once, but the mountains are ecstatic, and ought to be visited in pilgrimage once a year. None but those monstrous creatures of God know how to join so much beauty with so much horror. A fig for your poets, painters, gardeners, and clergymen, that have not been among them, their imagination can be made up of nothing but bowling-greens, flowering shrubs, horse-ponds, Fleet ditches, shell-grottoes, and Chinese rails. Then I had so beautiful an autumn; Italy could hardly produce a nobler scene, and this so sweetly contrasted with that perfection of nastiness and total want of accommodation, that Scotland only can supply.'—Gray'sWorks, edit. E. Gosse, vol. iii. p. 223.

[50]Journey to the Western Islands of Scotland, 1775, p. 84.

[51]Sedgwick did his best to enlighten the poet by his famousFour Letters on the Geology of the Lake District; but these came too late. They were published at Kendal in 1846, and Wordsworth died in 1850.

[52]Some drill and boreThe solid earth, and from the strata thereExtract a register, by which we learn,That He who made it, and revealed its dateTo Moses, was mistaken in its age.—The Task, bk. iii. 150.

[52]

Some drill and boreThe solid earth, and from the strata thereExtract a register, by which we learn,That He who made it, and revealed its dateTo Moses, was mistaken in its age.—The Task, bk. iii. 150.

Some drill and bore

The solid earth, and from the strata there

Extract a register, by which we learn,

That He who made it, and revealed its date

To Moses, was mistaken in its age.

—The Task, bk. iii. 150.

[53]You may trace him oftBy scars which his activity has leftBeside our roads and pathways, though, thank Heaven,This covert nook reports not of his hand—He who with pocket-hammer smites the edgeOf luckless rock or prominent stone, disguisedIn weather-stains or crusted o'er by NatureWith her first growths, detaching by the strokeA chip or splinter—to resolve his doubts:And, with that ready answer satisfied,The substance classes by some barbarous name,And hurries on; or from the fragments picksHis specimen, if but haply interveinedWith sparkling mineral, or should crystal cubeLurk in its cells—and thinks himself enriched,Wealthier, and doubtless wiser, than before!The Excursion, bk. iii.

[53]

You may trace him oftBy scars which his activity has leftBeside our roads and pathways, though, thank Heaven,This covert nook reports not of his hand—He who with pocket-hammer smites the edgeOf luckless rock or prominent stone, disguisedIn weather-stains or crusted o'er by NatureWith her first growths, detaching by the strokeA chip or splinter—to resolve his doubts:And, with that ready answer satisfied,The substance classes by some barbarous name,And hurries on; or from the fragments picksHis specimen, if but haply interveinedWith sparkling mineral, or should crystal cubeLurk in its cells—and thinks himself enriched,Wealthier, and doubtless wiser, than before!The Excursion, bk. iii.

You may trace him oft

By scars which his activity has left

Beside our roads and pathways, though, thank Heaven,

This covert nook reports not of his hand—

He who with pocket-hammer smites the edge

Of luckless rock or prominent stone, disguised

In weather-stains or crusted o'er by Nature

With her first growths, detaching by the stroke

A chip or splinter—to resolve his doubts:

And, with that ready answer satisfied,

The substance classes by some barbarous name,

And hurries on; or from the fragments picks

His specimen, if but haply interveined

With sparkling mineral, or should crystal cube

Lurk in its cells—and thinks himself enriched,

Wealthier, and doubtless wiser, than before!

The Excursion, bk. iii.

[54]St. Ronan's Well, chap. ii. The passage is quoted postea p. 166.

The Origin of the Scenery of the British Islands[55]

The insular position of these islands, which we are apt to regard as an essential and aboriginal feature, is merely accidental, and has not always been maintained. The intimate relation of Britain with the Continent is well shown by the Admiralty charts. If the west of Europe were elevated 200 feet—that is, the height of the London Monument—the Straits of Dover, half of the North Sea, and a large part of the English Channel would be turned into dry land. If the elevation extended to 600 feet—that is, merely the united heights of St. Paul's and the Monument—the whole of the North Sea, the Baltic, and the English Channel would become land. There would likewise be added to the European area a belt of territory from 100 to 150 miles broad, stretching to the west of Ireland and Scotland.

With an uprise of 600 feet a vast plain would uniteBritain to Denmark, Holland, and Belgium, and would present two platforms,[56]of which the more southerly would stretch from what are now the Straits of Dover northward to the northern edge of the Dogger Bank, where a steep declivity, doubtless a prolongation of the Jurassic and Cretaceous escarpments of Yorkshire, descends to the northern or lower platform. This submarine escarpment is trenched towards the west by a magnificent valley through which the united waters of the Rhine and Thames would flow, between the Dogger Bank and the Yorkshire cliffs. Another gap further east would allow the combined Elbe and Weser to escape into the northern plain. Possibly all these rivers would unite on that plain, but, in any case, they would fall into a noble fjord which would then be revealed following the trend of the southern coast line of Norway. Altogether an area more than thrice that of Britain would be added to Europe. By a total rise of 1800 feet, Britain would be united to the Faroe Islands and Iceland; while the Arctic and Atlantic Oceans would be separated.

GEOLOGICAL CHARACTERISTICS OF BRITAIN.

From its position on the oceanic border of a continent, Britain has been exposed to a great variety of geological change. In such a position marine erosion and deposit are most active. A slight upheaval or depression, which would have no sensible effect in the interior of a continent, makes all the difference between land and water on the coast-line. Moreover, there appears to be a tendency to special disturbance alongthe edge of an ocean. America affords the most marked proofs of this tendency, but in the structure of Scandinavia and its prolongation into Scotland and Ireland there appear to be traces of similar ancient ridging up of the oceanic border of Europe.

There is a remarkable convergence of geological formations in Britain, each carrying with it its characteristic scenery. The rugged crystalline rocks of Norway reappear in the Scottish Highlands; the fertile chalk, with its smooth downs and gentle escarpment, stretches across to us from the north of France; the great plain of North Germany, strewn with the debris of the northern hills, extends into our eastern lowlands; even the volcanic plateaux of Iceland and Faroe are prolonged into the Inner Hebrides and the north of Ireland.

The present surface of Britain is the result of a long, complicated process in which underground movements, though sometimes potent, have only operated occasionally, while superficial erosion has been continuous, so long as any land has remained above the sea. The order of appearance of the existing features is not necessarily that of the chronological sequence of the rocks. The oldest formations have all been buried under later accumulations, and their re-emergence at the surface has only been brought about after enormous denudation. In its general growth, Britain like the rest of Europe has, on the whole, increased from the north by successive additions along its southern border. Some early upheavals ridged up the Palæozoic rocks into folds running north-north-east and south-south-west, as may yet be seen in Scotland, in the LakeCountry, and in Wales. By a later series of plications the younger Palæozoic rocks were thrown into north-and-south and east-and-west ridges, the latter of which still powerfully affect the topography in southern Ireland, and thence through South Wales and Belgium. An east-and-west direction was followed by the more important subsequent European disturbances, such as those that upheaved the Pyrenees, Jura, and Alps.[57]Some of the latest movements that have powerfully affected the development of our scenery were those that gave the Secondary rocks their general tilt to south-east. It is very doubtful if any part of the existing topography can be satisfactorily traced back beyond Middle or Older Tertiary time.[58]The amount of erosion of some of the hardest rocks of the country since that date has been prodigious, as may be seen in the fragmentary condition of the volcanic plateaux of the Inner Hebrides.

GENERAL TOPOGRAPHY.

The main topographical features of Britain may be arranged as mountains, tablelands, valleys, and plains. All our Mountains are the result of erosion on areas of land successively upheaved above the sea. In the development of their forms, the general outlines havebeen mainly determined by erosion, independent of geological structure; while the details have been chiefly guided by structure, but partially also by the rate and kind of erosion. Ruggedness, for example, has resulted primarily from structure, but has been aggravated by greater activity of erosion. The mountainous west, with a greater rainfall and steeper slopes, is more rugged than the mountainous east.

The Tablelands of Britain are of two orders—1, those of Deposit, which may be either (a) of sedimentary rocks, horizontal or nearly so, as in the Millstone Grit and Jurassic plateaux of Yorkshire, or (b) of volcanic rocks, as in the wide plateaux of Antrim, Mull, and Skye; 2, those of Erosion, where, as the result of long-continued degradation, a series of plicated rocks has been cut down into a more or less uniformly level surface, as in South Wales. By the elevation of such a surface into a high plateau, erosion becomes more active, and the plateau is eventually trenched into a system of ridges and isolated hills, as has happened in the Highlands.

The Valleys of Britain are the result of erosion either (a) guided by geological structure, as in what are called longitudinal valleys, that is, valleys which run along the strike or outcrop of formations, as the Great Glen and Glen Spey in Scotland and the valleys of the Trent and Avon in England; or (b) independent of geological structure, as in the transverse valleys which embrace the great majority of British examples.

Our Plains are due to prolonged erosion, as in the Weald; to the deposit, ofdetritus, as in river-terraces and alluvial plains; to the action of the sea, asin raised beaches; and to ice, as in the drift-covered lowlands.

The existing Watershed of Britain is profoundly significant, affording a kind of epitome of the geological revolutions, through which the surface of the country has passed. It lies nearer the west than the east coast. The western slope being thus the steeper, as well as the more rainy, erosion must be greater on that side, and consequently the watershed must be slowly moving eastward. Probably the oldest part of the watershed is to be found in the Highlands, where its trend from north-north-east to south-south-west was determined by the older Palæozoic upheaval. Its continuity has been interrupted by the dislocation of the Great Glen. After quitting the Highlands it wanders across the Scottish Lowlands and Southern Uplands, with no regard to the dominant geological structure of these districts, as if, when its course was originally determined, they had been buried under so vast a mass of superincumbent rock that their structure did not affect the surface. Running down the Pennine Chain, the watershed traverses a region of enormous erosion, yet from its general coincidence with the line of the axis of elevation, we may perhaps infer that the anticline of the Pennine Chain has never been lost under an overlying sheet of later undisturbed rocks. The remarkable change in the character of the watershed south of the Pennine Chain carries us back to the time when the great plain of the Secondary rocks of England was upraised with a gentle inclination to east and south-east. The softer strata between the harder escarpment-forming members of the Jurassicseries and the Palæozoic rocks of the Pennine Chain were worn away, and two rivers carrying of the drainage of the southern end of that chain flowed in opposite directions, the Avon turning south-west and the Trent northwards. By degrees these streams moved away across the broadening plain of softer strata, as the escarpments emerged and retreated. At the same time, streams collected the drainage from the uprising slope of Secondary rocks and flowed south-eastward. Successive lines of escarpment have since been developed, and many minor watersheds have arisen, while the early watershed has undergone much modification, these various changes pointing to the continuous operation of running water.

THE MOUNTAINS AND TABLELANDS.

A true mountain-chain is the result of plication of the earth's crust, and its external form, in spite of sometimes enormous denudation, bears a relation to the contours produced by the original uplift. Tried by this standard, hardly any of the heights of Britain deserve the name of mountains. With some notable exceptions in the south of Ireland, they are due not to local but to general upheavals, and their outlines have little or no connection with those due to underground movement, but have been carved out of upheaved areas of unknown form by the various forces of erosion. In the course of their denudation, the nature of their component rocks has materially influenced the elaboration of their contours, each well-marked type of rock having its own characteristic variety of mountain forms.

The relative antiquity of our mountains must be decided not necessarily by the geological age of their component materials, but by the date of their upheaval or of their exposure by denudation. In many cases they can be shown to be the result of more than one uplift. The Malvern Hills, for example, which from their dignity of outline better deserve the name of mountains than many higher eminences, bear internal evidence of having been upheaved during at least four widely separated geological periods, the earliest movement dating from before the time of the Upper Cambrian, the latest coming down to some epoch later probably than the Jurassic period.

The oldest mountain fragments in Britain are those of the Archæan rocks, and of these the largest portions occur in the north-west of Scotland.[59]Most of our mountains, however, belong to upheavals dating from Palæozoic time, though the actual exposure and shaping of them into their present forms must be referred to a far later period. Two leading epochs of movement in Palæozoic time can be recognised. Of these the older, dating from before the Lower Old Red Sandstone and part at least of the Upper Silurian period, was distinguished by the plication of the rocks in a dominant north-east and south-west direction, and the effects of these movements can be traced in the trend of the Lower Silurian ridges and hollows to the present day.

In Wales two types of mountain-form exist—the Snowdon type, and that of the Breconshire Beacons.In the former, the greater prominence of the high grounds arises primarily from the existence of masses of volcanic rocks, which from their superior durability have been better able to withstand the progress of degradation. In the latter the heights are merely the remaining fragments of a once continuous tableland of Old Red Sandstone.

The Lake District presents a remarkable radiation of valleys from a central mass of high ground. It might be supposed that these valleys have been determined by some radiating system of fractures in the rocks; but an examination of the area shows them to be singularly independent of geological structure. So much do they disregard the strike, alternations, and dislocations of the rocks among which they lie that the conclusion is forced upon us that they have been determined by some cause independent of that structure, and before the rocks now visible were exposed at or could affect the surface. This could only have happened by the spread of a deep cover of later rocks over the site of the Lake mountains. The former presence of such a cover, which is demanded for the explanation of the valleys, can be inferred from other evidence. The Carboniferous Limestone on the flanks of the Lake District is so thick that it must have spread nearly or entirely over the site of the mountains. But it was overlain by the Millstone Grit and Coal-measures, so that the whole area was probably buried under several thousand feet of Carboniferous strata which stretched continuously across what is now the north of England. At the time of the formation of the anticlinal fold of the PennineChain, the site of the Lake District appears to have been upraised as a dome-shaped eminence, the summit of which lay over the tract now occupied by the heights from Scafell to Helvellyn. The earliest rain that fell upon this eminence would gather into divergent streams from the central watershed. In the course of ages, after possibly repeated uplifts, these streams have cut down into the underlying core of old Palæozoic rocks, retaining on the whole their original trend. Meanwhile the whole of the overlying mantle of later formations has been stripped from the dome, and is now found only along the borders of the mountains. The older rocks, partly faulted down and yielding to erosion, each in its own way, have gradually assumed that picturesqueness of detail for which the area is so deservedly famous.

The Scottish Highlands likewise received their initial plications during older Palæozoic time, their component rocks having been thrown into sharp folds trending in a general north-east and south-west direction.[60]But there is reason to believe that they were subsequently in large measure buried under Old Red Sandstone, and possibly under later accumulations. No positive evidence exists as to the condition of this region during the vast interval between the Old Red Sandstone and the older Secondary rocks. We can hardly believe it to have remained as land during allthat time, otherwise, the denudation, vast as it is, would probably have been still greater. Not improbably the region had become stationary at a base-level of erosion beneath the sea; that is, it lay too low to be effectively abraded by breaker-action, and too high to become the site of any important geological formation. The present ridges and valleys of the Highlands are entirely the work of erosion. When they began to be traced, the area probably presented the aspect of a wide undulating tableland. Since that early time the valleys have sunk deeper and deeper into the framework of the land, the ridges have grown narrower, and the mountains have arisen, not by upheaval from below, but by the carving away of the rest of the block of which they formed a part. In this evolution, geological structure has played an important part in guiding the erosive tools. The composition of the rock-masses has likewise been effective in determining the individuality of the mountain-forms.

The mountains of Ireland are distributed in scattered groups round the great central plain, and belong to at least three geological periods. The oldest groups probably took their rise at the time of the older Palæozoic upheaval, those of the north-west being a continuation of the Scottish Highlands, and those of the south-east being a prolongation of those of Wales. Later in date as regards the underground movements that determined their site, are the mountainous ridges of Kerry and Cork. These are local uplifts which, though on a small scale, are by far the best examples in Britain of true mountain-structure. The Old Red Sandstone and Carboniferous rocks have there been thrown intobroad arches and troughs which run in a general east and west direction. In some cases, as in the Knockmealdown Mountain, the arch is composed entirely of Old Red Sandstone flanked with Carboniferous strata. But in most instances an underlying core of Silurian rocks has been exposed along the centre of the arch. As not only the Carboniferous Limestone, but the rest of the Carboniferous system covered the south of Ireland and participated in this plication, the amount of denudation from these ridges has been enormous. On the Galty range, for example, it can hardly have been less but may have been more than 12,000 feet. The third and latest group of Irish mountains is that of Mourne and Carlingford, which may with some probability be referred to older Tertiary time when the similar granitic and porphyritic masses in Mull and Skye were erupted.

The Tablelands of Britain strictly include the mountains, which are in general only prominences carved out of tablelands. There are still, indeed, large areas in which the plateau character is well shown. Of these the most extensive and in many respects the most interesting is the present tableland or plain of Central Ireland. As now exposed, this region lies upon an undulating eroded surface of Carboniferous Limestone. But it was formerly covered by at least 3,000 or 4,000 feet more of Carboniferous strata, as can be shown by the fragments that remain.[61]The present system of drainage across the centre of Ireland took its origin long before the ancient tableland had been reducedto its present level, and before some of the ridges, now prominent, had been exposed to the light.

The Moors and Wolds of Yorkshire present us with a fragment of a tableland composed of nearly horizontal Jurassic and Cretaceous rocks. The Lammermuir Hills and Southern Uplands of Scotland extend as a broad tableland which has been formed on a deeply eroded surface of Lower and Upper Silurian rocks.

The Scottish Highlands may also be looked upon as the relics of an ancient tableland cut out of highly crumpled and plicated schists. Among the eastern Grampians large fragments of the plateau exist at heights of more than 3,000 feet, forming wide undulating plains that terminate here and there at the edge of precipices. In the Western Highlands, the erosion having been more profound, the ridges are narrower, the valleys deeper, and isolated peaks more numerous (p. 112). It is the fate of a tableland to be eventually cut down by running water into a system of valleys which are widened and deepened, until the blocks of ground between are sharpened into ridges and trenched into separate prominences. The Highlands present us with far advanced stages of this process.

In the youngest of British tablelands—that of the volcanic region of Antrim and the Inner Hebrides—we meet with some of the earlier parts of the change. That interesting tract of our islands reveals a succession of basaltic sheets which appear to have spread over the wide valley between the Outer Hebrides and the mainland, and to have reached southwards beyond Lough Neagh. Its original condition must have resembled that of the lava-fields of Idaho and Oregon—a sea-likeexpanse of black basalt stretching up to the base of the mountains. What may have been the total thickness of basalt cannot be told; but the fragment remaining in Ben More, Mull, is more than 3,000 feet thick. So vast has been the erosion since older Tertiary time that the volcanic plateau has been trenched in every direction by deep glens and arms of the sea, and has been reduced to detached islands. It is strange to reflect that all this revolution in the topography has been effected since the soft clays and sands of the London Basin were deposited.

THE VALLEYS.

The intimate relation of a system of valleys to a system of drainage lines, first clearly enunciated by Hutton and Playfair, has received ample illustrations from all parts of the world.[62]But the notion is not yet extinct that, in some way or other, valleys have been as much, if not more, determined by subterranean lines of dislocation than by superficial erosion. Some favourite dogmas die hard, and though this dogma of fracture has been demolished over and over again, it every now and then reappears, dressed up anew as a fresh contribution to scientific progress. We have only to compare the surface of a much dislocated region with its underground structure, where that has been revealed by mining operations, as in our coal fields, to see that valleys comparatively seldom, and then only as it were by accident, run along lines of dislocation, but that they everywhere cut across them, and that faults rarely make a feature at the surface, exceptindirectly by bringing hard and soft rocks against each other.

In Britain, as in other countries, there is a remarkable absence of coincidence between the main drainage system and the geological structure of the region. We may infer from this fact either that the general surface, before the establishment of the present drainage system, had been reduced to a base-level of denudation above or under the sea, the original inequalities of configuration having been planed off irrespective of structure; or at least, that the present visible rocks were buried under a mass of later unconformable and approximately level strata, on the unequally upraised surface of which the present drainage system began to be traced. Where the existing watershed coincides generally with the crest of an anticline, its position has obviously been fixed by the form of the ground produced by the plication, though occasionally an anticline may have been deeply buried below later rocks, the subsequent folding of which along the same line would renew the watershed along its previous trend. Where drainage lines coincide with structure, they are probably, with few exceptions, of secondary origin; that is, they have been developed during the gradual denudation of the country. Since the existing watershed and main drainage-lines of Britain are so independent of structure, and have been determined chiefly by the configuration of the surface when once more brought up within the influence of erosion, it may be possible to restore in some degree the general distribution of topography when they were begun.

One of the most curious aspects of the denudationof Britain is its extraordinary inequality. In one region the framework of the land has been cut down into the very Archæan core, while in the immediate vicinity there may be many thousands of feet of younger strata which have not been removed. This inequality must result from difference in total amount of upheaval above the base-line of denudation, combined with difference in the length of exposure to denudation. As a rule the highest and oldest tracts will be most deeply eroded. Much of the denudation of Britain appears to have been effected in the interval between the close of the Carboniferous and end of the Triassic period.[63]This was a remarkable terrestrial interval, during part of which the climate was so arid that salt lakes were formed over the centre of England. Yet the denudation ultimately accomplished was enormous, thousands of feet of Carboniferous rock being entirely removed from certain areas, such as the site of the present Bristol Channel. An interesting analogy to this condition of things is presented by the Great Basin and adjoining tracts of Western America, where at the present time marked aridity and extensive salt-lakes are accompanied by great erosion.

The deeply-eroded post-Carboniferous land of Britain was eventually screened from further degradation, either by being reduced through denudation to a base-level orby being protected by submergence. It was to a large extent covered with Secondary rocks, though the covering of these may have been but thin over what are now the higher grounds. The present terrestrial areas emerged at some period later than the Chalk.[64]In England there were three chief tracts of land—Wales, the Pennine Chain, and the Lake District. The eastern half of the country, covered with Secondary rocks, was probably the last portion to be uplifted above the sea; hence the watersheds and drainage lines in that tract may be regarded as the youngest of all.

The history of some of the valleys of the country tells the story of the denudation. The Thames is one of the youngest rivers, dating from the time when the Tertiary sea-bed was raised into land. Originally its source probably lay to the west of the existing Jurassic escarpment of the Cotswold Hills, and it flowed eastward before the Chalk escarpment had emerged. By degrees the Chalk downs have appeared, and the escarpment has retreated many miles eastward.The river, however, having fixed its course in the Chalk, has cut its way down into it, and now seems as if it had broken a path for itself across the escarpment. As all the escarpments are creeping eastward, the length and drainage area of the Thames are necessarily slowly diminishing.

The Severn presents a much more complex course; but its windings across the most varied geological structure are to be explained by its having found a channel on the rising floor of Secondary rocks between the base of the Welsh hills and the nascent Jurassic escarpments. The Wye and Usk afford remarkable examples of the trenching of a tableland. The Tay and Nith are more intricate in their history. The Shannon began to flow over the central Irish plain when it was covered with several thousand feet of strata now removed. In deepening its channel it has cut down into the range of hills north of Limerick, and has actually sawn it into two.[65]

THE LAKES.[66]

The Lakes of Britain present us with some of the most interesting problems in our topography. It is obvious that the existence of abundant lakes in the more northern and more rocky parts of the countrypoints to the operation of some cause which, in producing them, acted independently of and even in some measure antagonistically to the present system of superficial erosion. It is likewise evident that as the lakes are everywhere being rapidly filled up by the daily action of wind, vegetation, rain, and streamlets, they must be of geologically recent origin, and that the lake-forming process, whatever it was, must have attained a remarkable maximum of activity at a comparatively recent geological epoch. Hardly any satisfactory trace is to be found of lakes older than the present series. How then have our lakes arisen? Several processes have been concerned in their formation. Some have resulted from the solution of rock-salt or of calcareous rocks and a consequent depression of the surface. The 'meres' of Cheshire, and many tarns or pools in limestone districts, are examples of this mode of origin. Others are a consequence of the irregular deposit of superficial accumulations. Thus, landslips have occasionally intercepted the drainage and formed lakes. Storm-beaches, thrown up by the waves along the sea-margin, have now and then ponded back the waters of an inland valley or recess. The various glacial deposits—boulder-clays, sands, gravels, and moraines—have been thrown down so confusedly on the surface that vast numbers of hollows have thereby been left which, on the exposure of the land to rain, at once became lakes. This has undoubtedly been the origin of a large proportion of the lakes in the lowlands of the north of England, Scotland, and Ireland, though they are rapidly being converted by natural causes into bogs and meadow-land.Underground movements may have originated certain of our lakes, or at least may have fixed the direction in which they have otherwise been produced.[67]

A large number of British lakes lie in basins of hard rock, and have been formed by the erosion and removal of the solid materials that once filled their sites. The only agent known to us by which such erosion could be effected is land-ice. It is a significant fact that our rock-basin lakes occur in districts which can be demonstrated to have been intensely glaciated. The Ice-Age was a recent geological episode, and this so far confirms the conclusion already enforced, that the cause which produced the lakes must have been in operation recently, and has now ceased. We must bear in mind, however, that it is probably not necessary to suppose that land-ice excavated our deepest lake-basins out of solid rock. A terrestrial surface of crystalline rock, long exposed to the atmosphere, or covered with vegetation and humus, may be so deeply corroded as, for two or three hundred feet downward, to be converted into mere loose detritus, through which the harder undecomposed veins and ribs still run. Such is the case in Brazil, and such may have been also the case in some glaciated regions before the glaciers settled down upon them. This superficial corrosion, as shown by Pumpelly, may have been very unequal, so that when the decomposed material was removed, numerous hollows would be revealed. The ice may thus have had much of its work already donefor it, and would be mainly employed in clearing out the corroded debris, though likewise finally deepening, widening, and smoothing the basins in the solid rock.

THE HILLS AND ESCARPMENTS.

The Hills and Hill-groups of Britain have all emerged during the gradual denudation of the country, and owe their prominence to the greater durability of their materials as compared with those of the surrounding lower grounds. They thus represent various stages in the general lowering of the surface. In many cases they consist of local masses of hard rock. Such is the structure of the prominent knobs of Pembrokeshire and of Central Scotland, where masses of eruptive rock, formerly deeply buried under superincumbent formations, have been laid bare by denudation. In connection with such eruptive bosses, attention should be given to the 'dykes' so plentiful in the north of England and Ireland, and over most of Scotland. In numerous instances, the dykes run along the crests of hills, and also cross wide and deep valleys. Had the present topography existed at the time of their protrusion, the molten basalt would have flowed down the hill-slopes and filled up the valleys. As this never occurs, and as there is good evidence that a vast number of the dykes are not of higher antiquity than the older Tertiary periods, we may conclude that the present configuration of the country has, on the whole, been developed since older Tertiary time—a deduction in harmony with that already announced from other independent evidence.

Escarpments are the prominent outcrops of flat orgently inclined strata, exposed by denudation. They may be regarded as the steep edges of hills in retreat. The British islands abound in admirable examples of all ages from early Palæozoic rocks down to Tertiary deposits, and of every stage of development, from an almost unbroken line of cliff to scattered groups of islet-like fragments. The retreat of our escarpments can be well studied along the edge of the Jurassic belt from Dorsetshire to the headlands of Yorkshire, likewise in the course of the edge of the Chalk across the island. Not less suggestive are some of the escarpments of more ancient rocks, such as those of the older Palæozoic limestones, the Old Red Sandstone of Wales, the Carboniferous Limestone and Millstone Grit of Yorkshire, and the Coal Measures of the Irish plain. Our volcanic escarpments are likewise full of interest, as displayed in those of the Lower Old Red Sandstone along both sides of the Tay, in those of the Carboniferous system in Stirlingshire, Ayrshire, Bute, and Roxburghshire, and in those of the Tertiary series in Antrim and the Inner Hebrides.

THE PLAINS.

The Plains of Britain, like those elsewhere, must be regarded as local base-levels of denudation, that is, areas where, on the whole, denudation has ceased, or at least has become much less than deposit. Probably in all cases the areas they occupy have been levelled by denudation. Usually a greater or less depth of detrital material has been spread over them, and it is the more or less level surface of these superficial accumulations that generally forms the plain. But insome instances, such as the flats of the Weald Clay and the Chalk of Salisbury Plain, there is hardly any such cover of detritus, the denuded surface of underlying rock forming the actual floor on which the vegetable soil rests.

Our plains, if classed according to the circumstances of their origin, may be conveniently regarded as (1) river plains—strips of meadow-land bordering the streams, and not infrequently rising in a succession of terraces to a considerable height above the present level of the water; (2) lake plains—tracts of arable ground occupying the sites of former lakes, and of which the number is ever on the increase, owing to the filling-up of the basins with sediment; (3) plains consisting of portions of upraised sea-floors—partly eroded rock-platforms, but mostly flat selvages of alluvial ground, formed of littoral materials deposited when the land lay below its present level: in the northern estuaries these raised beaches spread out as broad carse-lands, such as those of the Tay, Forth, and Clyde; (4) glacial drift plains—tracts over which the clays, sands, and gravels spread out during the Ice-Age form the existing surface; (5) plains of subaërial denudation which have been levelled by rain and other atmospheric agents, especially upon tracts of rock of fairly uniform resistance, such as the soft clays and sands of the Secondary and Tertiary formations; (6) submarine plains—the present floor of the North Sea and of the Irish Sea, which must be regarded as essentially part of the terrestrial area of Europe.

When plains remain stationary at low levels, theymay continue for an indefinite period with no material change of surface. But, should they be upraised, the elevation, by increasing the slope of the streams, augments their erosive power, and enables them once more to deepen their channels. Hence, plains like that of the New Forest, which have been trenched by the water-courses that traverse them, may with probability be assigned to a time when the land stood at a lower level than it occupies at present. In this connection the successive river-terraces of the country deserve attention. They may be due not to the mere unaided work of the rivers, but to the cooperation of successive uplifts. It would be an interesting inquiry to correlate the various river-terraces throughout the country, for the purpose of discovering whether they throw any light on the conditions under which the most recent uprise of the country took place. That the elevation proceeded intermittently, with long pauses between the movements, is shown by the succession of raised beaches. It may be possible to establish a somewhat similar proof among our river-terraces.

The submarine plains are by far the most extensive within the British area. The tendency of tidal scour and deposit must modify the form of the bottom. In the case of the North Sea, for example, this great basin of water is obviously being slowly filled up by the deposit of sediment over its floor. A vast amount of mud and silt is borne into it by the rivers of western continental Europe, and of the eastern coast of Britain; while at the same time the waves are cutting away the land on both sides of this seaand swallowing up the waste. We have only to contrast the colour of the Atlantic on the west of Ireland or of Scotland with that of the North Sea, to be assured of the wide diffusion of fine mud in the water of the latter. There is practically no outlet for the detritus that is thus poured into the basin of the North Sea. From the north a vast body of tidal water enters between Scotland and Norway, and travelling southward, aided by the strong northerly winds, sweeps the detritus in the same direction. On the other hand, another narrower and shallower tidal stream enters from the Strait of Dover, and, aided by the south-west winds, drives the sediment northward. Yet, making every allowance for the banks and shoals which this accumulating deposit has already formed, we can still, without much difficulty, recognise the broader features of the old land-surface that now lies submerged beneath the North Sea. As already mentioned (p. 131), it presents two plains or platforms, of which the southern has an average level of perhaps a little more than 100 feet below the surface of the water. This upper plain ends northward in a shelving bank, probably the prolongation of the Jurassic escarpment of Yorkshire, and is succeeded by the far wider northern plain, which lies from 100 to 150 feet lower, and gradually slopes northward until it is trenched by the great south Scandinavian submerged fjord. The drainage-lines of the united Rhine, Thames, etc., on the one side, and the Elbe, Weser, etc., on the other can still be partially traced on that sea-floor. The site of the Irish Sea was probably once a terrestrial plain dotted with lakes. This land-surface appears tohave been submerged before the whole of the present fauna and flora had reached Ireland.

THE COAST-LINE.

Some of the most characteristic and charming scenery of the British Islands is to be found along their varied seaboard. Coast scenery appears to depend for its distinctive features upon (1) the form of the ground at the time when by emergence or submergence the present level was established; (2) the composition and structure of the shore-rocks; (3) the direction of the prevalent winds, and the relative potency of subaërial and marine denudation.

The British coast-line presents three distinct phases: in many places it is retreating; in others it is advancing; while in a few it may be regarded as practically stationary. As examples of retreat, the shores of a large part of the east of England may be cited. In Holderness, for instance, a strip of land more than a mile broad has been carried away during the last eight centuries. Even since the Ordnance Survey maps were published in 1851, more than 500 feet have in some places been removed, the rate of demolition being here and there as much as five yards in a year. The advance of the coast takes place chiefly in sheltered bays, or behind or in front of projecting headlands and piers, and is due in large measure to the deposit of material which has been removed by the sea from adjoining shores. The amount of land thus added does not compensate for the quantity carried away, so that the total result is a perceptible annual loss. The best examples of astationary coast-line, where there is no appreciable erosion by the waves and little visible accumulation of detritus, are to be found among the land-locked fjords or sea-inlets of the west coast of Scotland. In these sheltered recesses the smooth striated rocks of the Ice-Age slip under the sea, with their characteristic glaciated surfaces still so fresh that it is hard to believe that a long lapse of ages has passed away since the glaciers left them.

Back to Index Next