Mountains of the Mind (7 page)

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:

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 with 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.

Following the line of one of the stream-cuts, I scrambled up the eastern slope of the glen to the wrack-line. The heather was slippery with clumps of melting snow, and I often had to put a hand down
into it to steady myself. As I neared the boulders I startled a ptarmigan, and it flew kekking up into the white sky, where it became a silhouette.

By the time I reached the boulders my hands were cold. I rubbed them noisily together, and then began to walk up the valley, from boulder to boulder, imagining the ice filling up the glen like a bath. Each rock was moated with dark earth, where the warmth it had gathered during the day had leached out and melted the surrounding snow. I kept walking along until the gradient steepened and I had to drop off again into the valley floor. The path took me near a patch of exposed rock perhaps ten square metres in area. I walked over, and crouched down to examine it. The horizontal striations scored into it showed that this rock had once been a scratching-post of the glacier which had created the valley and was one of the places where it had rubbed its tremendous underbelly along the ground.

I looked up from the rock. It had snowed recently, and the hills visible beyond the confines of the glen were grey beneath a thin fall of snow; their outlines softened. In the far distance their bulks could hardly be seen against the white winter air; only a few dark strokes defined them at all. They reminded me of charcoal sketch-work, or the simple lines of a Chinese water-ink painting.

After two hours I reached the gateway to the valley, guarded to the west by the cone of Stac-an-Iolaire, the Crag of the Eagle, and to the east by Bynack More and Bynack Beg. Looking down towards the forests of the north, I saw – russet against white – a herd of red deer, perhaps half a mile away from me, jogging across the hillside, picking up their knees where the heather or the snow deepened. I stood and watched for a few minutes the procession of the deer, the only moving objects in the landscape, and was suddenly swallowed up by time. Twenty thousand years ago, during the Upper Pleistocene era, the heathered granite across which the deer were moving would have been submerged beneath millions of cubic litres of ice. Sixty million
years ago floods of basalt lava would have been sluicing the land, as Scotland tore violently away from the landmasses of Greenland and North America. One hundred and seventy million years ago, Scotland would have been drifting through the northern tropics, and arid reddish deserts would have covered the area on which I was standing. About 400 million years ago, a Himalayan-scale range of mountains would have existed in Scotland, of which only the eroded stubs remain.

To understand even a little about geology gives you special spectacles through which to see a landscape. They allow you to see back in time to worlds where rocks liquefy and seas petrify, where granite slops about like porridge, basalt bubbles like stew, and layers of limestone are folded as easily as blankets. Through the spectacles of geology,
terra firma
becomes
terra mobilis
, and we are forced to reconsider our beliefs of what is solid and what is not. Although we attribute to stone a great power to hold time back, to refuse its claims (cairns, stone tablets, monuments, statuary), this is true only in relation to our own mutability. Looked at in the context of the bigger geological picture, rock is as vulnerable to change as any other substance.

Above all, geology makes explicit challenges to our understanding of time. It giddies the sense of here-and-now. The imaginative experience of what the writer John McPhee memorably called ‘deep time’ – the sense of time whose units are not days, hours, minutes or seconds but millions of years or tens of millions of years – crushes the human instant; flattens it to a wafer. Contemplating the immensities of deep time, you face, in a way that is both exquisite and horrifying, the total collapse of your present, compacted to nothingness by the pressures of pasts and futures too extensive to envisage. And it is a physical as well as a cerebral horror, for to acknowledge that the hard rock of a mountain is vulnerable to the attrition of time is of necessity to reflect on the appalling transience of the human body.

Yet there is also something curiously exhilarating about the contemplation of deep time. True, you learn yourself to be a blip in the larger projects of the universe. But you are also rewarded with the realization that you do exist – as unlikely as it may seem, you do exist.

Charles Lyell’s
Principles of Geology
, and the dozens of popular geological works which soon afterwards sought to emulate its success, opened the eyes of the nineteenth century to the dramatic hidden past of the earth. The common imagination began to respond to the aesthetics of inordinate slowness; to gradual changes wrought over epochs. And whatever one’s position
vis-à-vis
the grand tectonics of geological debate, or any of the many minor upsets and scuffles which disturbed the science in the nineteenth century, what was irrefutably wondrous – and terrifying – was the age of the earth: its inexpressible antiquity. In little under half a century, geology had unfolded the world backwards by billennia.

The seventeenth and eighteenth centuries had been the centuries when space was extended, when the realm of the visible had suddenly been increased by the invention of the microscope and the telescope. We have images from that era which remind us of quite how astonishing that sudden stretching of space must have been. There is the Dutch lens-grinder Antony van Leeuwenhoek, peering down his rudimentary microscope in 1674 to see a host of micro-organisms teeming in a drop of pond-water (‘The motion of most of these animalcules in the water was so swift, and so various upwards, downwards, and round about, that ’twas wonderful to see …’). There is Galileo scrying upwards through his telescope in 1609, and becoming the first human to realize that there are ‘lofty mountains’
and ‘deep valleys’ on the moon. And there is Blaise Pascal’s mingled wonder and horror at the realization that man is poised teeteringly between two abysses: between the invisible atomic world, with its ‘infinity of universes, each with its firmament, its planets, and its earth’, and the invisible cosmos, too big to see, also with its ‘infinity of universes’, stretching unstoppably away in the night sky.

The nineteenth century, though, was the century in which time was extended. The two previous centuries had revealed the so-called ‘plurality of worlds’ which existed in the tracts of space and the microcosms of atoms. What geology revealed in the 1800s was a multitude of ‘former worlds’ on earth, which had once existed but no longer did. Some inhabitants of these former worlds offered an excitement beyond the general thrill of antiquity. This was the range of monstrous creatures which had formerly lived on the earth: mammoths, mammals, ‘sea-dragons’ and dinosaurs (literally ‘fearfully great lizards’), as they were christened in 1842 by the palaeoanatomist Richard Owen. Fossilized bones and teeth had been plucked from the earth for centuries, but not until the early 1800s was it realized that some of these relics belonged to distinct, and extinct, species.

The French natural historian Georges Cuvier (1769–1832) did more than anyone to bring about this realization. For it was Cuvier who affirmed to the world the controversial fact of extinction, and in so doing created the conceptual framework needed to understand dinosaurs as fossil animals. Cuvier’s test-case was the woolly mammoth: by comparing the structures of fossilized mammoth bones with those of contemporary African and Indian elephants, he proved that the fossil bones belonged to a different species. In 1804, to an astonished audience at the Institut National in Paris, Cuvier announced that huge and hirsute elephants – no longer alive upon the earth – had once inhabited France and had almost certainly stomped and herded through what were now the immaculate gardens
of Versailles. In terms of girth, Cuvier was a not inconsiderable man, and inevitably he was soon nicknamed ‘The Mammoth’.