Mountains of the Mind Read online

  Buffon’s move was a canny one: by turning each biblical day into an epoch of indefinite length, he created the space and time necessary for geologists to begin their work of disinterring an authentic history for the earth, while at the same time staying within the bounds of respect for the scriptures. It was the work of Buffon and others like him which began the transformation of Ussher’s implausibly precise dating of 4004 BC into a totem of idiotic biblical literalism.* For, once the duration of the earth’s past was no longer confined to 6,000 years, it was possible to speculate more systematically on what changes might have been wrought over wider spans of time. The science of geology could emerge and define itself in this newly old earth, proofed against accusations of blasphemy.

  By the start of the 1800s, those thinkers interested in postulating a past for the earth had begun to separate into two loose schools of thought, conventionally called Catastrophism and Uniformitarianism. It should be said that geologists of the later nineteenth century – notably Charles Lyell (1797–1875) – tended to exaggerate the degree to which these two schools waged intellectual warfare on each other, and it is important to realize that, while opinions did differ, battle-lines were never clearly drawn between them.

  Catastrophists believed that the history of the earth was dominated by major geophysical revolutions: one or many past Götterdämmerungs which had convulsed the earth with water, ice and fire, and all but extinguished life. The earth was a cemetery, a necropolis in which were interred countless now-extinct species. Drastic tidal actions, global tsunamis, severe earthquakes, volcanoes, the passing of comets: these were what had shaped and shaken up the earth’s surface into its present disruption. One popular Catastrophic theory of mountain-formation suggested that, since the earth was cooling from a white-hot original state, its volume was slowly reducing and its surface was consequently prone to severe crumpling – just as the skin of an apple crinkles as it dries out. The world’s mountain ranges were corrugations or crumples in the earth’s skin.

  The counter-theory to this violently paroxysmal vision of the earth’s history was preached by the Uniformitarians. The earth had never been subject to a global catastrophe, they held. Earthquakes, yes; volcanoes, yes; tidal waves, yes – undoubtedly these phenomena had taken place throughout geological history. They were localized calamities, however: they had only racked and rearranged the landscape in their vicinity. Certainly, the earth’s surface had been subject to drastic change – evidence for this was visible in any mountain range, or on any coastline. But this change had been achieved astonishingly slowly, by the forces of wear and tear which were presently at work on the surface of the earth.

  Given sufficient time, argued the Uniformitarians, the conventional ordnance of nature – rain, snow, frost, river, sea, volcano, earthquake – could produce the largest effects. So what the Catastrophists took for evidence of disaster was in fact the result of a slow and enduring ground war. The cornerstone of Uniformitarian theory was that ‘the present is the key to the past’: in other words, the history of the earth could be inferred from the careful observation of present processes at work on its surface. It was a version of the water-dripping-on-stone idea: allow a river or a glacier enough time and it will slice a mountain in half. Time, great time – this was what the Uniformitarians needed for their theories to work, and so they ratcheted the beginning of the earth far further backwards than anyone had previously contemplated.

  The most celebrated of the early Uniformitarians, usually credited with paternity of what is now called the Old Geology, was the Scotsman James Hutton (1726–97). Hutton possessed an instinctive ability to reverse physical processes, to read landscapes backwards, as it were. Like all of the founding geologists, Hutton was a prodigious walker, and for decades he strode back and forth across the Scottish landscape, attempting by a blend of induction and imagination to intuit the processes which had brought it to its present state. Fingering the white quartz which seamed the grey granite boulders in a Scottish glen, Hutton understood the confrontation that had once occurred between the two types of rock; saw how under fantastic pressure the molten quartz had forced its way into the weaknesses in the mother granite. To be with Hutton was to inhabit a world with a past so deep as to be terrifying. One of his colleagues and admirers, John Playfair, famously described visiting a geological site on the Berwick coast with him. As Hutton explained the implications of the rock configuration, wrote Playfair, ‘the mind seemed to grow giddy by looking so far into the abyss of time’.

  Between 1785 and 1799 Hutton’s three-volume magnum opus, Theory of the Earth, appeared: the distillation of decades of meditation on landscape formation. In it he proposed that the earth we presently inhabit is merely a snapshot in a series of an unknown number of cycles. The apparent permanence of mountains and coastlines is in fact an illusion born of our diminutive life-spans. Were we to live for aeons, we would witness not only the collapse of civilizations, but the utter rearrangement of the earth’s surface. We would watch mountains being worn down by erosion to become plains, and we would see new landmasses being formed beneath the sea. Rubble eroded from the continents and laid down in sedimentary layers on the sea-floor would be lithified – turned to stone – by the exothermic core of the earth and then, over millions of years, would be lifted up to create new continents and new mountain ranges. Thus it was, said Hutton, that the shells which could be found embedded in the rocks of mountain-tops had not been washed there by the Deluge, but had been elevated from sea-floor to mountain-top by the patient, implacable processes of the earth.

  Hutton put no parentheses around the age of the earth: according to his vision, the earth’s history stretched backwards indefinitely into the past and unfurled indefinitely into the future. The final sentence of his book would toll through the centuries: ‘The result therefore of our present enquiry is, that we find no vestige of a beginning, – no prospect of an end.’ It was this inexpressible deepening of the earth’s history that was geology’s vital contribution to the common imagination.

  How did this geological revolution affect the way mountains were imagined? Once the geologists had shown the earth to be millions of years old and subject to immense and ongoing change, mountains could never be looked at in the same way again. Suddenly, these effigies of permanence had acquired an exciting, baffling mutability. Mountains, which seemed so durable, so eternal, had in actuality been formed, deformed and reformed over countless millennia: their current appearance was merely a phase in the perpetual cycles of erosion and uplift which determined the configuration of the earth.

  A new generation of mountain-goers was drawn to the hills by the ghostly landscapes which had suddenly opened up under the scrutiny of geology. ‘What I really saw as never before,’ wrote Horace-Bénédict de Saussure in the 1780s, ‘was the skeleton of all those great peaks whose connection and real structure I had so often wanted to comprehend.’ Geology provided a reason and an excuse – scientific inquiry – for travelling to the mountains. ‘A sentiment of curiosity, exceedingly natural, induces travellers from all parts of Europe to visit Mont Blanc, the highest point of the old world, and to examine the surrounding glaciers,’ observed an English journalist in 1801. ‘These places have recently acquired a new degree of interest – the geologue, the mineralogist, and mere amateur repair thither with avidity; and even women are amply indemnified for the fatigue of the journey by the pleasure arising from the view of objects entirely new to them.’ To look at mountains was now also to look into them: to imagine their past. The English scientist Humphry Davy put it well in 1805:

  To the geological enquirer, every mountain chain offers striking monuments of the great alterations that the globe has undergone. The most sublime speculations are awakened, the present is disregarded, past ages crowd upon the fancy, and the mind is lost in admiration of the designs of that great power who has established order which at first view appears as confusion.

  ‘Strata Types’, frontispiece to Humphry Davy’s
Elements of Agricultural Chemistry (1813), showing the different rock layers which geology had made visible.

  Here then was another vertigo – the giddiness inspired by deep time – to add to the more familiar and immediate kind one might feel on a steep mountainside. The experience of going to the mountains had become, as Burnet had suggested a century earlier, one not only of moving upwards in space, but also backwards through time.

  James Hutton might have fathered geology, but he was by no means its most stylish exponent. Aside from its resonant final lines, Hutton’s Theory was written in a prose as uniformly impenetrable as the Old Red Sandstone of which he was so fond. It would take thirty years and another legendary geologist to make truly popular geology’s rapid advances and staggering exposés, and to entice even more people into the mountains. Far more than Burnet or even Hutton, it was the Scottish geologist Charles Lyell who was responsible for educating the nineteenth century in the language and the imagination of geology.

  Charles Lyell was a lawyer before he was a geologist, and his forensic training had equipped him with a writing style of extreme clarity and elegance. Between 1830 and 1833 he published in three volumes The Principles of Geology: an Attempt to Explain the Former Changes of the Earth’s Surface by Reference to Causes Now in Operation, a work which carefully and beautifully laid out the arguments behind the Uniformitarian view that the study of the present was the key to the past. Principles quickly became required reading for the chattering classes of its day and was widely translated: eleven revised editions had been published by 1872.

  Lyell’s brilliance lay primarily in his marshalling of detail. As Charles Darwin would do later in The Origin of Species by Means of Natural Selection (1859), Lyell won over his audience with a combination of irresistibly accumulating facts – in this respect his writing resembled the processes it was describing – and illuminating anecdotes. There was something appealing, too, in the democracy of the knowledge Lyell was outlining. You did not need special equipment or long training to decipher the earth’s history: only an acute pair of eyes, a basic knowledge of Uniformitarian principles, and curiosity and courage enough to peer over the edge of the ‘abyss of time’. Given these minimal qualifications anyone could attend the most exciting show on earth – its past.

  To witness in action this new way of feeling about mountains, let us turn to the year 1835, and to the town of Valparaíso, ledged precariously on the Pacific coastline of Chile. The town’s name means Paradise Valley, and a less fitting name could not have been found for it. To begin with it does not occupy a valley, but rather the thin strip of approximately horizontal ground that runs between the Pacific combers and the range of red rock mountains which rise steeply up behind the town. And it is positively not paradisal. The steady offshore breeze which scours the surface earth, the steepness of the ground and the salty soil mean that there is no vegetation to speak of. There is little other life to be found here save for the human inhabitants, who have made their homes in huddles of low white-washed houses with red-tiled roofs, which congregate in the stream-cuts and ravines. Near the shoreline, dories bob in rows, ready to service the big ships that come to anchor out in the deeper water – for Valparaíso, unlikely as it may seem, is Chile’s principal sea-port. Over the whole scene hangs the clear, dry air of the coastal summer.

  It is from Valparaíso on 14 August 1835 that Charles Darwin sets out on horseback for a long excursion into the Andean hinterland. Out in the bay is moored his ship, the ten-gun brig HMS Beagle, on which he is serving as scientific observer. While studying at Cambridge, Darwin had become interested in geology, and before he sailed south from Devonport on a ferociously stormy evening in December 1831, he packed the first volume of Lyell’s Principles as reading for the long voyage out towards South America. He tested Lyell’s theories in the field during a stop at the Cape Verde Islands, and by the time the Beagle first sighted the flatlands of Patagonia, Darwin’s imagination was primed to interpret the landforms he encountered in Lyellian terms: to infer a deep past for their present appearance. ‘I always feel as if my books came half out of Lyell’s brains,’ he would later write to a friend, Leonard Horner, ‘for I have always thought that the great merit of the Principles, was that it altered the whole tone of one’s mind & therefore that when seeing a thing never seen by Lyell, one yet saw it partially through his eyes.’

  Leaving Valparaíso, Darwin first rides northwards along the coast for a day, in order to see the beds of fossilized shells which he has been told he must visit. They are astonishing – long banks of calcified molluscs which have been elevated, Darwin correctly deduces, by gradual crustal movement to their present resting-place several metres above the level of the sea. Having seen the shells – and having watched a gang of locals with pick and shovel plunder barrowloads of them for lime-burning – Darwin turns his horse inland, and canters up through the wide and fertile valley of Quillota (‘whoever called Valparaíso Valley of Paradise must have been thinking of Quillota’, he would observe later to his journal). The valley is densely packed with olive groves, and with stands of orange, peach and fig trees which have been manicured into tiny square orchards by the valley’s inhabitants. On its higher slopes prolific fields of wheat flash in the sunlight, and above them rises the Bell of Quillota, a 1,900-metre peak from which there are reputed to be magnificent views. It is this mountain which Darwin has come to climb.

  After spending a night in a hacienda at the foot of the mountain, Darwin procures a gaucho guide and fresh horses, and begins with difficulty to make his way up through the groves of thick-trunked palms and tall bamboo which flourish on the mountainside. The paths are not good, and by nightfall the two men are only three-quarters of the way to the summit. They pitch camp beside a spring, and beneath an arbour of bamboos the gaucho kindles a fire on which he fries beef strips, and boils water for maté. In the darkness the firelight dances off the walls of their arbour, and the bamboo seems briefly to Darwin like the architecture of some exotic cathedral, illuminated by flickering flames. The atmosphere is so clear and moonlit, the air so lucid, that Darwin can make out the individual masts of the ships anchored twenty-six miles away off Valparaíso, like little black streaks.

  Early the following morning Darwin clambers up the greenstone blocks to the flat summit of the Bell. From there he looks across to the white towers and ramparts of the Andes, and down at the scars left on the flanks of the lower hills by the voracious Chilean gold-mining industry. The view astonishes him:

  We spent the day on the summit, and I never enjoyed one more thoroughly. The pleasure of the scenery, in itself beautiful, was heightened by the many reflections which arose from the mere view of the grand range … Who can avoid admiring the wonderful force which has upheaved these mountains and even more so the countless ages which it must have required, to have broken through, removed, and levelled whole masses of them? It is well in this case to call to mind the vast shingle and sedimentary beds of Patagonia, which, if heaped on the Cordillera, would increase its height by so many thousand feet. When in that country, I wondered how any mountain-chains could have supplied such masses, and not have been utterly obliterated. We must not now reverse the wonder, and doubt whether all-powerful time can grind down mountains – even the gigantic Cordillera – into gravel and mud.

  From his eagle’s-nest perspective, Darwin’s eye roves around not only in space but also within time. Indeed, the pleasure of viewing the actual scenery laid out before him is secondary compared with the visions he has of the imagined scenery – the masses of snow-capped peaks and ranges which must once have existed here but, thanks to the ‘wonderful forces’ of geology, no longer do. Darwin is, in effect, gazing at range on range of mountains of the mind, made newly and marvellously visible to him by Lyell’s doctrines.

  Moments like this litter Darwin’s journals. One of the principal thrills for the many readers of his published account of the trip, The Voyage of the Beagle (a bestseller in its day), was to travel wit
h Darwin not only to the storm-hammered tip of Tierra del Fuego and the silver deserts of Patagonia, but also back and forth within the recently discovered expanses of geological time. The HMS Beagle was one of the world’s first time-travel ships – a prototype of the Starship Enterprise, whose warp drive was fuelled by a mixture of Darwin’s prodigious imagination and Lyell’s insights.

  Anyone who has spent time in wild landscapes will have experienced in some form this deepening of time which John Playfair sensed in Berwick and Darwin felt in Chile. Early one March I walked the length of Strath Nethy, a long Scottish valley which runs round the back of the Cairngorm mountains. In cross-section the glen, like all the glens in that part of the world, is shaped like a flattened U. It is shaped like this because until around 8,000 years ago the Scottish Highlands were overrun with glaciers, as were parts of Wales and Northern England, most of North America and significant sections of Europe. These glaciers moved gradually over the land: scooping it out, grinding it down, resculpting it.

  Walking the glen that day, I could see, two-thirds of the way up either flank, the high-tide mark of the glacial ice, plotted by the boulders which had been cast up there in a ragged line like sea-shore flotsam. The flanks of the valley were also incised laterally with dozens of little stream-cuts. The stream-cuts had been harrowed into the bedrock granite during the millennia since the glaciers retreated from the valleys. They had been cut by the insistent fretwork of the rainwater which ran away down the sides of the ridges. Once it has found a channel, water works away at deepening it – carrying off particles of rock, using those particles to strike other particles free – until it settles into its groove, and its groove becomes its channel, and its channel its stream-cut.