The Map That Changed the World (14 page)

And as for evolution—Darwin’s theory was not to be outlined for another twenty years, but men like Young, students of the realities of the fossil world, were already moving hesitantly toward the brink:

The Reverend Young could not, however, go any further than this: The forces ranged against him—of custom, history, doctrine, and common acceptance—were just far too formidable.

My own favorite, though sadly no more than a peripheral player in this story, is Samuel Woodward, a Norfolk collector and almost exact contemporary of Smith’s who worked for all of his forty-eight years in either an insurance office or a bank. He was fascinated by fossils and built up a large collection. He was not nobly born, however, nor could he have been described as a gentleman for whom paleontology was merely an idle pursuit for impressing the neighbors. He was ordinariness personified: His father had been a bombazine weaver, and his own apprenticeship was in the making of camlets.
*
Smith would probably have liked him: Both were men of modest beginnings, for whom fossils were more a passion, less a pastime for the
au courant
.

Yet it was not to be one of these modest men but a number of the more gently born collectors and spiritual figures whose influence was eventually to help place William Smith firmly on the flood tide of history. There was William Cunnington, a man still remembered around Devizes as being the antiquary who excavated most of the ancient long barrows with which the chalk downs of the country are littered. It was Cunnington who introduced Smith to the aforementioned Miss Bennett, who fascinated him
with her collection of sponges and corals. The man who would later become the Father of English Geology thus briefly encountered the person who, in some circles at least, is thought of as English Geology’s First Woman if not quite (since she remained unmarried, and was described as “somewhat mannish”) its mother.

There was the Reverend Richard Warner, a great man for both writing and walking,
*
but a figure who suffered “severe and reiterated disappointments”—for one of his books was judged a plagiary, another set of volumes was burned by mistake at the printer’s, and someone “dressed up as a gentleman” (or so wrote William Smith) made off with his immense fossil collection by giving him a check that then promptly bounced.

There was the somewhat happier Reverend Benjamin Richardson, the rector of the Somerset parish of Farleigh Hungerford. There was also Richardson’s longtime friend, the Reverend Joseph Townsend, who was by calling a doctor and a Calvinist minister, then living in Bath, who had been well and expensively educated at Cambridge and Edinburgh. Townsend had traveled widely in Spain, and had brought back hundreds of fossils from the local limestones. He had not, Smith was later to write with relief, drawn any conclusions from his finds, and he was to remark later, and ruefully, “Ah, Smith, were I now to go over to Spain again I should give a very different account of the country.”

He would do so because, for the first time, William Smith was beginning to take a keenly intelligent interest in not just the rocks in the cuttings of the coal canal, but of the fossils too. And once he had begun to do so, then who better with whom to discuss his discoveries than the local worthies who had amassed collections themselves? His newfound social standing, his now-close friendship with the widowed Lady Jones of Rugborne, his rela
tively good financial condition, his ownership (even if mortgaged) of a small and pretty estate at Tucking Mill, his brief occupancy of a substantial terraced house in Bath itself—all these features commended the uneducated Smith to learned men like Townsend and Richardson, Cunnington and Warner, and allowed them to play a role in his life that he would later acknowledge as of huge importance.

H
is work on the canal bed and its continuing line of progress was sometimes more confusing than it should be. Smith had no problem recognizing the differences between most of the strata, true: there was a very obvious difference between the red marl and the coal measures, an equally obvious difference between the spawnlike granules in the limestones of the inferior oolite and the arenaceous beds of the Lias. Yet some of the strata through which the excavators were making progress, particularly the finer-grained sandstones, looked too similar. From time to time it proved very difficult, Smith found, to differentiate one bed from another: In one cutting there may have been a sandstone and in another, half a mile away, there may have been another that looked identical—and yet, to judge from a dip and strike that did not vary between the two outcrops, logic suggested that the two formations were not the same at all, had been laid down at different times, and were in fact separated by hundreds, perhaps even thousands, of feet of vertical distance.

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:

Later, in more reflective mood, he would write: