is the author of The Man Who Invented the Chromosome: A Life ofCyril Darlington (Harvard University Press).

The Seashell on the Mountaintop: A Story of Science, Sainthood, andthe Humble Genius Who Discovered a New History of the Earth

By Alan Cutler

(Dutton, 228 pp.,

$23.95 )

The Man Who Found Time: James Hutton and the Discovery of theEarth's Antiquity

By Jack Repcheck

(Perseus, 247 pp.,



`Vast ... horrid, hideous, ghastly ruins." These are not the wordsof an observer of a latter-day war zone or a witness to the effectsof an ecological disaster on a city of yore. Rather, it was thetypical reaction of the seventeenth-century tourist when chancingupon ... the Alps! If this seems surprising, then consider also thepronouncement of Thomas Jefferson that there exists a riddle"beyond the investigation of human sagacity." Had Jefferson beenreferring to the conundrum of human consciousness, or the problem offree will, or perhaps the confounding paradox of a benevolent,all-powerful God who allows evil in this world, we would be remissin expressing our confusion. But the elusive puzzle too great forthe powers of the human mind was the mystery of seashells embeddedin stones atop mountains nowhere near the sea--what Jeffersoncalled "the origin of shells in high places." And what about theequally astounding admission by Isaac Newton that the universal lawsof mechanics that he had painstakingly described were doubtlesssuspended in the beginning of time to accommodate God'stwenty-four-hour, six-day adventure of the creation of the world?That the world was born on October 23, 4004 B.C.E., was an obviouscertainty to the Archbishop of Armagh, James Ussher, in his AnnalesVeteris Testamenti, in 1650.

It is all exceedingly strange to us. But two wonderful popularrenditions of the history of geology, by Alan Cutler and by JackRepcheck, take us back in time, geological and historical, to aworld very different from the one we live in today. The story thatholds the key to unlocking such curiosities of human understanding,it turns out, is a story conceived layer upon layer, in which theappearances of stones and ridges and fossils, the rise and fall ofcities and empires and professions, the vicissitudes of mundane andcelestial politics, and the evolution of human knowledge allfunction in the same manner: as palimpsest maps of time.

Yeats yearned for the "Land of Heart's Desire,/Where beauty has noebb, decay no flood,/But joy is wisdom, time an endless song," andprobably men and women of all ages have shared his desire. But thenotion that time functions for humans as it does for the earth isactually a modern concept, and it owes much to the two men whosestories are told so vividly in these two little-big books. Thathumankind has a history was clear to Aristotle and to Aquinas andto Luther, but that the Earth had a history was another matteraltogether. Wrinkles on the face of an old man are a testament tolong years of love and disappointment and anger and hope, but couldthe same thing be said of "wrinkles" on the face of the Earth? IfGod created a perfect Earth, could the present state of the naturalworld really be a key to its past?


Nicolaus Steno was born Niels Stenson in Copenhagen in the winter of1638, a decade before the Peace of Westphalia would finally bringsome quiet to a Europe ravaged by war. Contemporary observers ofthe debates between creationists and evolutionists, or betweenadvocates of stem-cell research and their foes, might be surprisedto learn that science and religion were not always at loggerheads,but rather nestled very comfortably in centuries past into acohesive and reassuring worldview sanctioned by scripture, belief,and observation. Centuries before the word "scientist" was coined(this happened in 1840), alchemists, experimental philosophers,natural historians, and natural philosophers plumbed the depths ofthe observable world, searching out the patterns and forces thatwould have been put in place by a benevolent God. The heroes of thescientific revolution of the seventeenth century were almost alldevout Christians; the chance to demonstrate the regularity of theuniverse as conceived by a merciful deity was a tempting prospectfor a clever young lad growing up at the time, and the dutifulSteno kindled to the challenge.

Just a short decade after having enrolled at the University ofCopenhagen to study medicine, Steno was lauded in the greatcapitals of Europe as one of the finest anatomists of his age."Neither a butterfly nor a fly escapes his skill, " an admirerwrote, having watched Steno dissect the eye of a horse at theSorbonne's prestigious Ecole de Medecine. "He would count the bonesof a flea-- if fleas have bones." It is to Steno that we owe thediscovery of the duct that supplies saliva to the mouth, and alsoof the tear-producing glands. It was Steno who challenged theprevalent notion that muscles act by the ballooning of their entiremass, rather than from the contraction of their fibers. (This ideawas rejected at the time, re-discovered by physiologists a centurylater, and re-affirmed at the molecular level in the 1980s.) Stenowas also the man who discovered that females of live-bearingspecies produce eggs, just like eggproducing species: anatomistshad previously assumed that mammalian female eggs were simplydegenerate testes.

Steno died in 1686, at the age of forty-eight. The aboveachievements would have been incredible for any scientific career,but they turn fantastical when we learn that Steno was ordained asa minister in 1675 at the age of thirty- seven (and actuallystopped working in science two years earlier) and that he isremembered today not for being a great anatomist, but rather as thefather, or the proto-father, of the science that would one day callitself geology.

He never finished his medical studies in Copenhagen; he traveled toAmsterdam and then to Leiden to do so. It was a doctor's duty at thetime to know something about stones. Cutler relates how crystals oftopaz pressed against a wound were believed to stop bleeding, oriron-ore hematite to ward off diseases of the blood. And so it isnot all that surprising that following a three-month stay inreligiously pluralist Amsterdam, where he met and befriendedSpinoza, Steno wrote his first scholarly paper on the subject ofhot springs.

Traveling through the great seats of learning of his day, Stenobegan to feel uneasy about the natural and mechanical philosophiestaught at the universities. Heirs of the Middle Ages, thesehallowed halls of learning were erected to preserve knowledge, notto create it. Centuries of tradition handed down from the ancientscould hardly be fallible; but what the eye could see might well bean illusion, prey to tricks of the mind and follies of the heart.As an anatomist, this became clear to Steno early on. He recognizedthat, as Cutler writes, "dissection was the art of opening up fleshto reveal what Galen said was supposed to be there. If what wasfound did not match the text, it was an embarrassment to thedissector, not to Galen."

The greatest blow to Steno's scientific idealism came care of thepineal gland of a human cadaver. Mechanism and skepticism were twovirtues of the Cartesian mechanical philosophy close to Steno'sexacting scientific heart, but Descartes had constructed hisphilosophy of man on the premise that humans differed from allother living things because they had souls, and could therefore notbe treated as mere devices whose motions and behavior could beaccounted for by his mechanical philosophy. In On Man, Descartesappointed the tiny nut-shaped pineal gland, nestled peacefully inthe center of the brain, to be the seat of the human soul. Thegyrations of this gland, he wrote, could account within his physicsfor the effects of the immaterial soul on the material body.

The only problem, as Steno's sharp eye grasped, was that the anatomyof the pineal gland did not accommodate any such gyrations. Thetiny nut was fixed and immobile, like a large granite outcrop inthe ground. The mechanical philosophy of Descartes was the pinnacleof scientific achievement of the day, yet Steno, hunched over somecorpse, grasped that the followers of Descartes were just asdogmatic as those of Galen had been. They saw what they wanted tosee. Perhaps what was practiced by men of science was notscientific enough, from the anatomy theater to the alchemicallaboratory to the natural expanse of the heavens. Disillusioned bywhat he took to be the facile standards of the science of his day,Steno turned from uncovering layer upon layer of human and animalflesh to probe a different kind of gradation--that of the endlessand mysterious strata of the layered Earth itself. Traveling toFlorence in 1665 to join the disciples of Galileo at Ferdinandod'Medici's famous Accademia del Cimento, he passed through the Alpsand the Apennines on his way to becoming "an anatomist of theworld."


Schools of thought in human history, like strata in geological time,come layered one atop the other. When Aristotle grappled with theproblem of "the origin of shells in high places," he harked back toa pre-Socratic tradition that imagined an ancient ocean coveringthe entire world. The waxing and waning of such a mammoth sea waspart of the "vital process" of a world with no beginning and noend. Seashells in mountains were simply deposited there overunfathomable tracks of immeasurable time. But Christian men ofscience at the gates of the seventeenth century could not allowsuch a pagan view. Only God was eternal to the Christian mechanist;time had direction, a beginning and an end. All of scripture wouldbe nonsense if the world itself was, as Aristotle said it was,eternal.

But then how to explain such unnatural natural phenomena asseashells found on mountains? The biblical flood was one option,yet the shells looked like those of saltwater species, and theflood was a consequence of fresh rain falling from God's sky.Besides, how could so many seashells be spread so widely in such ashort time, when the biblical flood, after all, was said to havelasted no more than a year? More difficult still was the problem ofchronology. If the solid earth and all its rocks were formed duringthe six days of God's creation, how then could seashells findthemselves embedded within rocks, if the deluge occurred long afterthese had already been formed? Luther's sola fide sola scripturaprovided the impetus for a new kind of religious natural thinkernot prone to solving such mysteries through metaphor and exegesis,but rather through a tough-minded look at what was there. But thepuzzle was difficult. Aristotle's waxing and waning may have beentrue if time were eternal, but it made little sense in asix-thousand-year-old world. What were these organic shapes withinrocks, and how, on God's earth, had they got there?

Neoplatonists and Hermetic philosophers found little in thesequestions to shake their understandings. Since the character andthe nature of living things were not determined by their biologicalproperties, but were emanations of ideas from the celestial realmof eternal forms, it stood to reason that some of the seashellsshould get caught in their downward motion on the mountaintops,which were, after all, the closest physical entities to the heavens.But for an increasing numbers of observers and thinkers such atheory would no longer suffice. "The delight the Renaissance mindtook in all forms of paradox and illusion," Cutler writes, "wasslowly being replaced by a more sober rationalism. Mysticism wasout, mechanics were in." The great English experimentalist RobertBoyle now wrote that "the works of God are not like the Tricks ofJuglers or the Pagents that entertain Princes." The works of Godwere lawful, and it was the task of the man of science to find anddescribe them.

Figuring out the problem of shells in rocks meant figuring out theultimate nature of matter itself, and about this, too, layers ofhuman judgment had deposited over the ages. For the ancient Greekphilosopher Thales, all matter was at base water, and the solidearth merely a hardened crust formed over a primeval ocean, andearthquakes the result of the shifting of this crust on the watersbelow. Empedocles some years later added air, fire, and earth tothe basic elemental fray, but it was the Roman Lucretius whofinally came up with the essential and reductive theory of all. InOn the Nature of Things, Lucretius described the natural philosophythat would see itself revived once again in the gilded age of theRenaissance, when the books of the ancients were re-printed andre-read by a growing intellectual middle class.

Atomism was the notion that all observable events and forms were theresult of random collisions between unseen elemental particles,called atoms, from the Greek for "indivisible." But as Cutlerskillfully relates, atomism presented a grave problem for theCatholic Church in the form of the Eucharist: if atoms wereimmutable, how could sacred transformations of matter ever reallyoccur? Lacking a solution to this difficulty, early modern naturalphilosophers refashioned Lucretius's atomism into the "corpuscular"theory of matter, retaining the rudiments of the theory butdropping the theological and metaphysical difficulties byabandoning the speculation on whether such atoms or corpuscles weredivisible or indivisible. Matter was an affair of pure geometry,and as Kepler (and Plato before him) knew, God was a geometer.

Pantheists, such as Steno's friend Spinoza, thought that mineralsand rocks could grow just like plants and animals. The greatseventeenth-century Jesuit scholar Athanasius Kircher, one of themost famous men in the world of his time, spoke of lapides suigeneris, or self-generated stones, that grew and gave birth, andeven came in varieties female and male. This is how Kircher, thechurch's scientific retort to Galileo, explained the otherwiseanomalous appearance of shells (mollusks were created on the fifthday) in rocks (created on the third day): a "plastic spirit"emanating from God constantly permeates the world, spontaneouslygenerating all kinds of wonders, such as flies in putrid meat andshells and fossils in already created crusts of earth and stone.Voltaire later preferred this explanation to the otherwiselaughable alternatives that he himself concocted, that shells inhigh places were either the remains of snacks discarded by alpinetravelers or ornamental badges lost by wandering pilgrims.

But a pious Lutheran such as Steno could hardly accept that thingshad their own life, even if it was imbued by God. After all, thecreative powers of nature might ultimately lead to belief in anature that is self-creating, leaving God aside. So a new breed ofseventeenth-century thinkers, mostly Protestant and devout,rejected animism and embraced corpuscles and mechanical philosophyinstead, giving a soul to man and a spirit to God and the angels,and judging all else to be nothing but inert, dumb matter. Thesemechanists offered physical explanations for the formation of thesolar system and the movements of the planets. And so it wasinevitable that scholars would begin to wonder if there might belaws that could explain the movements and histories on Earthitself, of mountains and oceans and ridges, and, ultimately, ofliving beings. Was it possible that unearthed fossils were remnantsof species that no longer walked the Earth? Was not extinctionoverruled in a world of special creation by God? Why were theresigns of volcanic activity in places with no human record of suchcatastrophe? Could there have been physical forces at work,changing the face of the planet, that no longer pertained today?Why, people wondered, was there obvious evidence of stratificationin the ground if there was no history to the Earth? What, in God'sname, would be the point? Nicolaus Steno wanted to find answers,and he went to Medician Florence to crack the mysteries of theEarth while holding on to the mystery of God.


That trees and seashells added layers as they grew was known wellbefore Steno's time. That the earth itself was made of layers wasapparent to the ancients as well. What Steno accomplished was not,strictly speaking, a feat of observation; he did not see with hiseyes formations that others had failed to notice, something thatJames Hutton would do a century later. Steno's leap was tounderstand that the layering in the earth represented a sequence inwhich time had a direction. The sequence, in other words, was achronology--a map of how the earth had changed over time. This mayseem trivial to us today, but it was absolute anathema to aseventeenth-century sensibility.

The key to turning the tide was Steno's insistence that science askonly questions that could be answered--in his case "Which camefirst?" rather than "How long ago?" "If a solid body is enclosed onall sides by another solid body, " Steno wrote in hisseventy-eight-page masterpiece De Solido, in 1668, "the first ofthe two to harden was that one which, when both touch, transferredits own characteristics to the surface of the other."

It sounds simple, but it was this piece of logic that helped for thefirst time to distinguish between a quartz pebble embedded in asedimentary deposit and a quartz vein following a fracture in thesame deposit, or between an oyster nestled in a nook of a sandstoneboulder and a cockleshell found in that same sandstone, havingimpressed its signature ribs on the surrounding stone. This novelnotion of chronology--the idea that from the present world vanishedworlds can be awakened--now spawned three simple and basicprinciples. First, the "principle of superposition"--when ageological layer was forming, those layers observed above it todaywere not in existence; layers are laid in sequence. Second, the"principle of original horizontality"--a layer's currentorientation notwithstanding, it was once horizontal, since water isthe source of all sedimentation, and water always arranges itselfparallel to the horizon, no matter what cavity it fills. Steno knewthat since the earth is not static but dynamic, strata often becomevertical, or even completely overturned. How, then, could one knowthe proper sequence? By assuming, Steno answered, that whensediments are formed from water, the larger, weightier particlessettle first, the flightier, smaller grains slowly settling on top.Sediments, by their internal structure, could serve as maps oftheir own creation. And so, third, there emerged the "principle oflateral continuity," which showed that just as tilted strataimplied the movements of a dynamic earth, so too did "bared edges"of strata--sudden breaks in an otherwise continuous layer--implythat what is now a mountain had once been a valley. The Earth had ahistory that could be painstakingly deciphered by observing theforms apparent today.

These three principles are now referred to as "Steno's Principles"and are recited in their sleep by all first-year geology students.Their importance as, so to speak, the bedrocks of geologicalscience derives from the scientific principle that Steno followedwhen deducing them centuries ago: science is the art of answeringthe answerable, not of imagining the imaginable. (Similarly, Newtoncomprehended this when he perceived that he could not discover thenature of gravity, but could instead devise a mathematics thatunified the motion of the carriage with the revolutions of themoon.) Steno resolved to tackle what could be reasonablyapproached, setting in place the principles that would define forposterity the science of the earth.

Steno was a religious man. When Spinoza's TractatusTheologico-Politicus was published, attacking organized religion,Steno wrote him a letter to express his discontent: "You do notthink there exists any certainty besides demonstrative certainty,and are ignorant of the certainty of faith which is above alldemonstration." And then the man who championed asking questionsthat could be answered forsook scientific inquiry to be ordained asa minister of the church. "Beautiful is what we see," Cutler quoteshis hero. "More beautiful is what we understand. Most beautiful iswhat we do not comprehend." Steno, as he told his scientificadversary and friend Kircher, was giving up science as a sacrificeto God. Becoming the titular bishop of Titiopolis, an ancient seesomewhere in Asia Minor that had long been lost to the Turks and theexact location of which was not quite known (what was referred toby the church as in partibus infidelium--in the land of theinfidels), Steno died in 1686, free of any worldly possessions andprofessing the "agreement between Nature and Scripture." For Steno,the world was about 5,600 years old, so perhaps it is fitting thatin 1988, 202 years after his death, he was beatified by Pope JohnPaul II on October 23--the very date Bishop James Ussher hadcarefully calculated for the creation of the world.


I once spent a carefree summer as a stagehand in one of the manytheaters of the Edinburgh Fringe Festival. The particular theater Ihelped to construct was built inside an old gray-stone churchcalled Greyfriars Kirk, its facade charred, like many an Edinburghbuilding, with the black soot of the industrial revolution. Littledid I know at the time that beneath the earth in the kirk'sbackyard cemetery lay one of the great figures in the history ofgeology. Such is the nature of scientific and historical knowledge:like sediments and strata, it accumulates one layer at a time.

James Hutton was born in 1726, just forty years after Steno's death.But the world into which Hutton was born was as different fromSteno's as limestone is from granite. Of Steno's day, Cutlerwrites, "The Renaissance had pretty much run its course. Theconvulsions of the Protestant reformation had mostly subsided. TheAge of Enlightenment, on the other hand, was barely on the horizon.It was an awkward, in-between age--reborn, reformed, but not yetenlightened." That might help to explain the apparent paradox of aman who showed that the Earth has a history, but who neverthelessinsisted that it was only as old as the Bible said it was. Hutton,by contrast, was born into an Edinburgh very much at the heart ofthe new-old world. In the short span of Hutton's generation, theScottish Enlightenment would produce Hume's philosophy and Smith'seconomics and Ferguson's sociology and Robertson's historiographyand Watt's steam engine.

Scotland had been ruled for centuries by Jacobites, CatholicHighlander clansmen, the Scottish equivalent of feudallandlords--the followers of James II, the Catholic monarch deposedin 1688. It was these very clansmen who on a dark night in July1745 tiptoed down to a Western Highland beach to meet James II'sgrandson, Charles Stuart or Bonnie Prince Charlie, as he disembarkedfrom a small frigate carrying himself and only seven followers in abid to recapture the lost Stuart throne. By mid-September, PrinceCharles marched into Edinburgh unopposed, and decided to pushsouthward, leading his clansman army all the way to Derby, just 130miles north of London. But when rumors of an English force ofthirty thousand made their way to the Catholic camp, the clan chiefsforced their ambitious prince to capitulate.

As Jack Repcheck beautifully relates, the march back to Scotland wasthe beginning of the end for Stuart claims to the English monarchy,as well as the beginning of the end for Old Scotland. Quickly,Westminster dispatched the duke of Cumberland northward to destroythe fleeing clansmen, and the "harrying of the glens" became thename for the terrible pacification that ensued. English laws nowstripped the clan chiefs of all authority; clan councils, thewearing of tartans, the playing of pipes, even the speaking ofGaelic--all were outlawed. Highland culture became a thing of thepast.

Edinburgh, on the other hand, was now free to accept back its WhigPresbyterians, a progressive merchant, jurist, and intellectualclass largely descended from Lowland families in the territoriessouth of Edinburgh and Glasgow that had been settled over thecenturies by invading Normans, and then English, and with a stronginterest in economic and academic ties with London. The ModerateParty of Presbyterian Whigs, William Robertson proclaimed, saw"industry, knowledge, and humanity linked together by anindissoluble chain." No surprise, then, that "Auld Reekie," asEdinburgh was called--referring to the stench of chimneys andpollution, and an unusual system of waste removal (out thewindow)--was increasingly described as the Athens of the North.

The young James Hutton enrolled to study at the University ofEdinburgh in this atmosphere at the tender age of fourteen,unaware, most assuredly, that if, as Repcheck writes, "Copernicustook man away from the divine center of things, " he would one daytake man away from "the divine beginning of things." Hutton endedup studying medicine in the Paris of Voltaire, Diderot, andRousseau, and finishing up in Leiden in 1749. Edinburgh would oneday become a center of medical studies, but the continentalcapitals of learning still offered a lad with sincere pretensionsthe best training available. Cities and professions, like fossils,arrange themselves in historical layers; like dinosaurs, once-great seats of learning are forgotten; like small mammalian shrews,once-great seats of ignorance all of a sudden become exalted.

Hutton ended up forsaking his white robe for the gloves and boots ofa farmer on a piece of inherited land, returning to Scotland aftermaking a small fortune from a company that made sal ammoniac (usedas flux in metalworking) from common coal soot. The next thirteenyears were spent at his farm, Slighouses, learning and applying newmethods of agriculture, and nursing an increasing curiosity in whatwas now called geology. Repcheck tells us that Hutton read the ninetreatises on the Earth that encompassed all known geologicalthought of his day, among them Steno's De Solido; Thomas Burnet'sThe Sacred Theory of the Earth, a treatise of biblical Newtonianism;and William Whiston's New Theory of the Earth, which invoked cometcollisions to explain the biblical deluge. Most interesting,perhaps, for it broke with biblical chronology (then considered oneof the exact sciences), was Benoit de Maillet's anonymouslyauthored Telliamed in 1748. Benoit's thinly veiled treatise (thetitle is his surname spelled backward) was the first ever topropose that the world was ancient--about two billion years old. ButTelliamed was not accorded much scientific respect, probably due tothe fact that it was said to have been written by an Orientalphilosopher following ancient Egyptian legend, who argued, amongother things, that women and men originated from mermaids andmermen.

Buffon's thirty-four-volume Histoire Naturelle, which appeared in1749, was a different story altogether; after all, Buffon was theintendant of the Jardin du Roi and a respected member of France'sscientific elite. This did not stop the faculty of the Sorbonnefrom sending him a missive in the winter of 1751 informing him thatfourteen ideas in his book had been found "reprehensible andcontrary to the creed of the church." Repcheck tells us that theoffending lines were these: "The waters of the sea have producedthe mountains and valleys of the land--the water of the heaven,reducing all to a level, will at last deliver the whole land overto the sea, and the sea, successively prevailing over the land,will leave dry new continents like those which we inhabit." Buffon,in other words, had suggested that God had not created themountains and the valleys directly, but rather through the agenciesof the waters of the seas and of the skies. He was made to(perfunctorily) recant.

`Things are made known only by comparison," wrote Hutton'sbiographer and close friend John Playfair, "and that which isunique admits of no description. " Hutton was indeed a uniquecharacter, wearing clothes "often found in direct collision" withcurrent fashion, and living unmarried with three spinster sistersuntil the very end of his life. He was particularly unique when itcame to geology. Realizing that the erosion he witnessed daily onhis own land carried grains of dirt into streams, which flowed intorivers, which flowed into seas, where the grains sedimented andeventually turned into rock, Hutton saw that there must be amechanism for the restoration of soil, for otherwise the land wouldquickly become uninhabitable, a result that the believing Huttoncould not reconcile with a benevolent God.

Intense heat and pressure at the core of the Earth would have to bethe mechanism that accounted for the consolidation of sediments andtheir elevation from the seabed to replace the land that haderoded. The elevation could not be the result of receding waters ofan ancient and vast ocean, as the German Abraham Gottlob Werner,the leading European geologist of the day, had claimed. For if thiswere so, all stratified rock would be horizontal, in the shape ithad originally formed on the floor of lakes, seas, and oceans. Buteveryone knew that strata were often found in every degree of"fracture, flexure, and contortion." Forces from within, powerfulbut slow-working, would explain the formation and re-formation ofland on Earth; shrinking and expanding waters just didn't seem upto the job.

If the cycle of the land described by Hutton in two invited talks tothe Royal Society of Edinburgh in 1785 was true, as everyone nowunderstood, there arose the question of time. "As there is not inhuman observation proper means for measuring the waste of land uponthe globe," Hutton proclaimed, "it is hence inferred, that wecannot estimate the duration of what we see at present, norcalculate the period at which it had begun; so that, with respect tohuman observation, this world has neither a beginning nor an end."The earth was so unimaginably ancient that Hutton would not evenhazard a guess as to its age.

But unlike Steno, Hutton would actually demonstrate to the worldsomething it had not yet seen. At Glen Tilt, he had found in thebed of the river gorgeous red granite veins frozen like lightningin the sedimentary black rock into which they had once gushed frombelow. This was ample proof that granite was formed by subterraneanheat and pressure, but it did not yet prove Hutton's theory ofcycles. Then, on a sunny afternoon in the summer of 1788, from asmall boat beneath a rock exposure on the weather-beaten cliffs ofSiccar Point, Hutton finally found it: a formation of vertical andhorizontal sedimentary rocks, which left no doubt that what hadhappened was the result of the process of erosion, sedimentation,heat and pressure, elevation, and then erosion again, just as hehad described. Knowing the modest rate at which deposits settle, itwas immediately clear that what was being observed was the result ofmillions and millions of years of geology. "The mind seemed to growgiddy by looking so far into the abyss of time," Playfair wrote."We find no vestige of a beginning- -no prospect of an end" wasHutton's own poetic reaction. He had discovered, Bible and delugeand Methuselah aside, the awesome concept of deep time.

Hutton died in 1797, at the age of seventy. The early 1800s saw thefounding of the Geological Society of Great Britain, and with itthe strengthening of a group of "catastrophists" who, like Wernerwith his ancient ocean, continued to perform impressive mentalacrobatics to try to fit the story of the Earth into the story ofthe Bible. Catastrophists now argued that volcanic forces, whichthey could no longer ignore, had been vastly more powerful in thepast, so that measurements of geological dynamics today could teachlittle of what had come before. "None of the agents that she nowemploys were sufficient for her ancient works," the FrenchmanGeorges Cuvier wrote about nature. Once again, discounting thenotion that present observation could explain the past helped topreserve a relatively young earth, keeping James Ussher's chronologyin the margins of the King James Bible, and of the hearts and mindsof men.

Finally, in the 1820s, the Scotsman Charles Lyell, following a visitto Siccar Point, resurrected Hutton's geology, this time for good.Lyell's principle of uniformitarianism--the notion that presentforces were exactly the same in the past--became the bedrock of hisgradualist geology, a geology that now took Hutton's cycle and deeptime as givens. Charles Darwin took Lyell's Principles of Geologyto read on the Beagle, and much has been written about histranslation of Lyell's gradualism in the rocks to the gradualtransformations in nature. So the intellectual epic stretching backin time-- from Lucretius and Aristotle through Steno, Descartes,Kircher, Spinoza, Hutton, Lyell, and Darwin; from Rome throughCopenhagen through Amsterdam, Paris, Leiden, Florence, Edinburgh,and the GalApagos Islands; from paganism through Catholicismthrough Reformation through Enlightenment--eventually tells itstale in wondrous and serpentine ways.

Geology describes a linear record with many a cycle within; time hasan arrow, but it also travels in circles. And in life, as in therocks, what goes around comes around: one of Hutton's closestfriends, with whom he made many of his geological excursions anddiscoveries, was George Clerk-Maxwell, the great- great-grandfatherof James Clerk-Maxwell, whose nineteenth-century studies ofmagnetism would play a role in the 1960s in providing scientificevidence for continental drift. This was the clincher for the longdisregarded and disbelieved theory of plate tectonics proposed byAlfred Wegener earlier in the century, which now stands as theunifying theory of geology. I am pretty certain that Steno wouldhave been shocked to learn of deep time and evolution andtectonics, and I am equally confident that Hutton would have beenglad to witness such developments from his pastoral resting placebehind Greyfriars Kirk. But I'd give a dinosaur fossil in mintcondition to know what Steno and Hutton, the two forgotten fathersof the science of the Earth and each embedded in a world of hisown, would make of the modern poet's great lines: "Time present andtime past/Are both perhaps present in time future/And time futurecontained in time past."

By Oren Harman