The Map That Changed the World

by Simon Winchester

To understand the nature of this problem it is perhaps easier to imagine something of the circumstances when the rocks were being laid down. Think, for example, of the conditions in the Lower and Middle Jurassic in North Somerset—something, it is worth remembering, that Smith would have been quite unable to imagine since he had no idea of the ages of the rocks he examined, of the paleogeography of the region, of any of the concepts that permeate modern geology.

  He would not have known what modern science allows us to know, which is that for most of the 51-million-year period of time that began 208 million years ago, when the Jurassic opens, most of North Somerset was covered by a shallow sea, at the western edge of a vast ocean called the Tethys. In addition, since all England was then positioned about thirty-five degrees north of the equator, the waters were subtropical, and warm.

  But the sea in those days, much like the sea today, was not uniformly deep, and, since it was at the edge of the Tethyan Ocean, it was at times close to landmasses from which, in places, rivers cascaded or seeped, estuaries were formed, volcanoes erupted, cliffs collapsed, and where currents of sand and water swept down through deep ocean canyons. Paleogeography is a study that involves the constant remembrance of time and space, as well as all the physical conditions in which a particular rock type may be laid down—meaning that at any one time, several different rock types may be being deposited or created at different places; and that over any extended period of time the very same rock—or at least, rocks with the very same lithology—may be being laid down at different places.

  The extent of the Tethyan Ocean in Middle Jurassic times, 152 million years ago.

  Hence the confusion. When William Smith was looking at the sandy outcrops of the Upper Lias in a few square miles around the village of Midford, say, he might find a succession of sandy beds in one valley, and another succession of sandy beds in another valley, that looked to all intents and purposes the same, but that his knowledge of their dip and strike and distance apart persuaded him were not the same at all—that the bed lying on top was younger than (that is, had been deposited more recently than) the bed that lay below.

  The conditions governing the type of rock, the facies, that had been laid down in each of these two valleys had been exactly the same—they had been deposited near the beach of a warm and shallow sea, with maybe some incoming muddy deposits from a nearby river. But their attitude—going back to the bread-and-butter analogy he had come up with back in his High Littleton days—still applied: they could not have been the same bed of rock, and they must have been separated by scores, maybe hundreds of feet—and hundreds of feet meant at the very least, a long period of time. What the outcrops indicated was two different periods of time, when the same conditions for deposit obtained. How, then, to tell the rocks apart?

  The answer lay in Smith’s sudden realization that there was just one aspect of the two types of rock, and only one, that differed. The blocks of stone found in the cuttings may have all had the same color, an acid bottle would show them all to have the same chemistry, a magnifying lens would show the sandstones as all having the same grain size. But the fossils that were to be found in the two rocks—the bivalves, the ammonites, the gastropods, the corals—they were all subtly different.

  Every single one of the specimens of one kind of fossil might be the same throughout one bed, but would be subtly different from those of the same kind of fossil found in another bed. A period of time would have elapsed between the deposition of the two beds, and thus a period of time between the existence of the two kinds of animals it embraced. Evolution—we can say this today, but Smith had not even the vaguest conception of it back then—would have occurred. Those animals of which there would be fossilized remains that were found lower down in the series would be more primitive; those found in the rock layers above, less so. But that was not the point. The important discovery that Smith made was that certain beds had certain fossils, that they were unique and peculiar to that bed and to that period of time in geologic history. They were never to be seen again in rocks that came later—in other words, in the rocks that appeared above. They were never seen before, either: They were peculiar, that is to say, to a certain and specific period in geologic time; they were the key to making a positive identification of what one rock might be in relation to any other.

  Day after day during the late summer and autumn of 1795, whether he was working surveying the canal or simply clambering over rocks that interested him while his horse champed contentedly beside him, Smith tested and retested his theory. At each outcrop he came to he would gingerly chip and pry and prise as many fossils as he could from their enfolding rock. Each evening he would take his specimens back to his elegant new terraced home in Bath. He would wash and dry each fossil, be it a pedestrian looking oyster shell or the magnificent twirling fantasy of a full-blown ammonite, and lay each carefully, on a pad of cotton, in drawer after drawer of his cabinets, carefully noting the rock, the horizon, the facies, and the lithology from which each came.

  And as his systematic collecting proceeded, and as the size and quality of his collection was daily enhanced, so his theory was confirmed and reconfirmed: A layer of rock, it now seemed incontrovertibly true, could be positively and invariably identified simply and solely by the fossils that were to be found within it.

  Wherever in the hills around Bath a sandstone appeared with a particular specimen of fossil enclosed within, then it was certain that it was the very same rock, laid down at the very same time. And if this rock-and-fossil assemblage appeared not just in the hills around Bath, but in the valleys of Oxfordshire too, and was found in a quarry in Rutland, beside a road in Lincolnshire, on a peak near York, and finally in a cliff near Whitby, then it, too was the selfsame rock. Not just a similar rock: the same rock. And then, the corollary said, by joining the dots of its occurrence across the land, one could show just where this particular rock occurred all over the nation, and whether it made an outcrop or not. And one could do this not just in the nation, but in theory all over the world. One of the enigmas that was central to an unraveling of the mysteries of the planet had now demonstrably been solved. What he had vaguely imagined might be true when he looked through the mines near High Littleton, was clearly an axiom, a fundamental fact of the new geological knowledge. And he, William Smith, was the first to say so.

  Smith was exultant at his realization, and committed his thoughts to paper with excited promptitude. He was in the Swan Inn at Dunkerton, sheltering from the cold on the evening of Tuesday, January 5, 1796. He had decided that evening not to brave the elements, not to go back home to Bath. He took a sheet of paper and wrote in his distinctively bold handwriting a long single sentence. The note survives, its underlining preserved for posterity. It was a sentence that, of all he wrote, is perhaps most deserving to be his epitaph:

  Fossils have long been studied as great curiosities, collected with great pains, treasured with great care and at a great expense, and showed and admired with as much pleasure as a child’s rattle or a hobby-horse is shown and admired by himself and his playfellows, because it is pretty; and this has been done by thousands who have never paid the least regard to that wonderful order and regularity with which Nature has disposed of these singular productions, and assigned to each class its particular stratum.

  Later, in more reflective mood, he would write:

  For six years I put my notions of stratification to the test of excavation; and I generally pointed out to contractors and others, who came to undertake the work, what the various parts of the canal would be dug through. But the great similarity of the rocks of the Oolite, on and near the end of the canal towards Bath, required more than superficial observation to determine whether these hills were not composed of one, two or even three of these rocks, as by the distinctions of some parts seemed to appear. These doubts were at length removed by more particular attention to the site of the organic fossils which I had long collected. This discovery of the mode of identifying the strata by the
organised fossils respectively imbedded therein led to the most important distinctions.

  In reflective mood Smith seems more the engineer, less the romantic. In middle age he is, and understandably, no longer quite so astonished at the “wonderful order” that he had realized the fossils displayed—an astonishment of discovery which today remains the most haunting aspect of that hastily scribbled note made at the Swan Inn. But the message remains the same, however eloquent or sentimental the prose. A puzzle had been solved. A riddle unscrambled. Now was the time to make something of the answer.

  9

  The Dictator in the Drawing Room

  Zigzagiceras zigzag

  Some Romans had called what we call Bath Aquae Calidae—the hot waters. others preferred Aquae Sulis, naming the scalding springs in homage to the presiding Celtic water deity, later twinned with their very own Minerva. And for the two thousand years since centurions first erected their stone bathing stalls at this most convenient stopping place on the frontier between the Roman and the Celtic worlds, Bath has been an important, memorably unusual, and often very fashionable place. “Oh!” exclaims Catherine Morland in Jane Austen’s Northanger Abbey, “who can ever be tired of Bath?”

  Nowadays it is the combination of social style, elegance, and fine building stone—tales of the costume parties of Beau Nash, the buildings of a famous father and son, both called John Wood, and the honey-colored oolites of the Middle Jurassic—that still, in the main, impress. The tour groups line up in endless succession before the Royal Crescent and the Circus, the Assembly Rooms and the baths themselves, eager to revel in the pleasures of majestic architecture and public grace. Tens of thousands of visitors throng the streets, passing briefly through the compact little city, within its amphitheater of hills. It is, for tourists, one of the score of essential English way stations between the great pile of Buckingham Palace and the artless country cottage of Anne Hathaway.

  A few visitors come to stay, and some to study, and an even smaller number to take the hydropathic cure by drinking some of the most foul-tasting mineral waters with which the mantle’s heat has ever supplied us. “Particklery unpleasant,” Sam Weller had said a century ago, in The Pickwick Papers. “A wery strong flavour o’ warm flatirons.” But efficacious, they used to say in the century before Dickens, and in those days the finer folk of England would flock to Bath in their thousands, and lodge, imbibe, and amuse themselves, and amuse all the envious world that looked on.

  But people also came to Bath to study, discuss, debate, and argue. The citizens of Bath—the population in 1800 had risen dramatically, to thirty thousand—liked to think of themselves as inhabiting the nation’s second city, in matters both social and intellectual. Few of the citizenry had forgotten that Adelard—“England’s first scientist”—a twelfth-century philosopher who had written treatises on the abacus and the astrolabe, had been born in Bath.

  Only London attracted finer minds, just as only London had grander parties and soirées. And so in 1777 a move was made to establish and formalize the intellectual ambitions of the city, by creating a society that had as its sole purpose the encouragement of the discussion and dissemination of ideas. The Bath Chronicle of August 28 carried an advertisement, placed by a weaver’s son named Edmund Rack, and directed at “The Nobility and Gentry in the Counties of Somerset, Gloucestershire, Wiltshire and Dorset in General, and the Cities of Bath and Bristol in Particular.”

  They were to consider, Rack wrote, a proposal for “the institution of a Society in this city, for the encouragement of Agriculture, Planting, Manufactures, Commerce and Fine Arts.” The tone, flattering and seductive to the city’s elite, evidently worked: Twenty-two of the noblest and gentlest-born of Bath’s citizenry turned up at a meeting held a week later in what would later be the Royal York Hotel, and the first of the distinguished intellectual societies for which the city would become famous was formally constituted.

  An impressive roll call of luminaries chose over the years to become associated with or full members of the various new bodies—the Bath and West of England Society, the Bath Agricultural Society, the Bath Philosophical Society, the Literary Society, and today’s successors to them all, the Bath Royal Literary and Scientific Institution and the Royal Bath and West of England Society (now based in Shepton Mallet). There was Joseph Priestley (who discovered oxygen); Thomas Malthus (the economist and population expert), Sir William Herschel (who discovered Uranus* lurking way at the back of the solar system), Humphry Davy (who discovered sodium and potassium), and one Augustus Voelcker, a German, who was a specialist in the chemistry of cheese and set up a school to teach cheesemaking in Wells, nearby.

  And on December 22, 1796, it was announced at the annual meeting that, elected unanimously in consequence of his growing reputation for canal making, his expertise in farming, and his keen new interest in his unromantic freelance business of solving problems with the drainage of fields, membership of the Bath and West of England Society was gained by one of the least noble and least gently born men in the city, the blacksmith’s son from Oxfordshire, William Smith.

  His social standing was improving fast. The same annual meeting recorded that the duke of Bedford, the earl of Egremont, and the earl of Peterborough—farmer-aristocrats all—were in the same company as Smith, and he himself noted that in the years following he came to know each of them well. At the time of his election he had a house on a good terrace in Bath, and his more or less permanent lodgings in the Swan Inn at Dunkerton, which he used when he was delayed in the countryside on canal business. He was well paid, well regarded, sought after. And now, through the Bath Society, he found he was winning friends in influential places—members like the vicars Benjamin Richardson and Joseph Townsend, both of whom were fossil collectors, owners of immense houses in the city—and travelers in the circle of the fashionable; and fellow members like John Billingsley and Thomas Davis—the latter the land steward to the marquess of Bath at his nearby estate at Longleat—who were at the time engaged in writing exhaustive studies of the state of local farming for the Somerset and Wiltshire Boards of Agriculture.

  It was this latter pair who first introduced William Smith to the notion of making maps. Although, as we shall see, history has been more generous in its assessment of the importance in William Smith’s extraordinary story of the Reverends Richardson and Townsend, it was actually Billingsley and Davis who gave him the idea that would be central to his coming achievement. For while Smith had no difficulty at all in displaying the vertical extent of the geology he found—he just drew cross-sections and tables as everyone else did—he had the very greatest difficulty in working out how to display the way in which these strata were exposed horizontally, how the outcrops of different kinds of rock were displayed geographically.

  Except that one day in late 1798 he suddenly saw just how he could do it. He was reading the latest edition of the Somerset County Agricultural Report, and there, buried without comment among the statistics on pigs and the effects of new cattle cross-breeding programs, Smith found an intriguing small map. Billingsley and Davis, it turned out, had sketched their latest in a series of maps for the report that showed, crudely but effectively, the geographical extent of each of the various soils and types of vegetation that were known in the countryside around Bath.

  The maps were detailed and, moreover, they were colored: with the use of blues and yellows and greens, all painstakingly applied by hand, they showed the local forests, meadows, pastures. The maps displayed graphically all the nearby hills, rivers, and lakes. And, most important for Smith, they hinted at what lay underneath the surface of the earth, by showing, also in colors, the outcrops of the red earth, the courses of the coal.

  In a flash Smith now realized the possibilities. If ordinary agricultural men like Billingsley and Davis were capable of making maps that could display such details, then, with his even greater graphical skills and now a good deal of new and detailed knowledge about just what lay beneath the surface, he hi
mself could draw charts that would show the courses followed by all the rocks that he knew lay down below.

  He could use his skills and unusual knowledge, in other words, to draw a brand-new map the likes of which had never been known. He could draw a chart of what could not be seen. And in doing so he could create what had never been created before—a true geological map.

  His diaries and notes showed that he then puzzled over the finest details—most important, whether he could make the maps relatively inexpensively, by drawing the outcrops in black and white, by using lines of different thickness or by using cross-hatching, to illustrate the different rocks. But he decided he could not. Color, costly though it was to print, and time consuming to apply, was in his view essential for a chart that would be so complex as a map of the unseen underworld. He thus embarked upon a technique of coloring that he was to embrace for the following thirty years of his cartographic career.

  He decided first to start his mapping by applying his new techniques to what he knew—the area in the immediate vicinity of Bath itself. By happy chance in the early summer of 1799 a new book was published, The Historic and Local New Bath Guide, printed by A. Taylor and W. Nayler, Booksellers. Its frontispiece turned out to be a handsome map of the city—a map Smith immediately felt he could use as a base on which to superimpose what he now knew about the geology.

  Taylor and Nayler’s map was somewhat unusual in appearance, not least because it was circular, about fifteen inches in diameter. It was on a scale of one and one-half inches to the mile. Bath lay in the center, like a bull’s-eye. The Avon wandered across from northwest to southeast. The Kennet and Avon Canal was marked, as was the still-not-quite-completed Somerset Coal Canal. The countryside for five miles in either direction was depicted in some detail, with grand houses, stands of trees, parish churches, the turnpikes and common roads, and “with Alterations and Improvements to the present Time.” It was uncolored and, despite holding plenty of important information was designed in a nicely uncluttered way. For William Smith’s purposes it was ideal.