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

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

by Alan Cutler

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In the bestselling tradition of The Map that Changed the World and Longitude comes the tale of a seventeenth-century scientist-turned-priest who forever changed our understanding of the Earth and created a new field of science.

It was an ancient puzzle that stymied history's greatest minds: How did the fossils of seashells find their way far


In the bestselling tradition of The Map that Changed the World and Longitude comes the tale of a seventeenth-century scientist-turned-priest who forever changed our understanding of the Earth and created a new field of science.

It was an ancient puzzle that stymied history's greatest minds: How did the fossils of seashells find their way far inland, sometimes high up into the mountains? Fossils only made sense in a world old enough to form them, and in the seventeenth century, few people could imagine such a thing. Texts no less authoritative than the Old Testament laid out very clearly the timescale of Earth's past; in fact one Anglican archbishop went so far as to calculate the exact date of Creation...October 23, 4004, B.C.

A revolution was in the making, however, and it was started by the brilliant and enigmatic Nicholas Steno, the man whom Stephen Jay Gould called "the founder of geology." Steno explored beyond the pages of the Bible, looking directly at the clues left in the layers of the Earth. With his groundbreaking answer to the fossil question, Steno would not only confound the religious and scientific thinking of his own time, he would set the stage for the modern science that came after him. He would open the door to the concept of "deep time," which imagined a world with a history of millions or billions of years. And at the very moment his expansive new ideas began to unravel the Bible's authoritative claim as to the age of the Earth, Steno would enter the priesthood and rise to become a bishop, ultimately becoming venerated as a saint and beatified by the Catholic Church in 1988.

Combining a thrilling scientific investigation with world-altering history and the portrait of an extraordinary genius, The Seashell on the Mountaintop gives us new insight into the very old planet on which we live, revealing how we learned to read the story told to us by the Earth itself, written in rock and stone.

Editorial Reviews
Barnes & Noble Discover Great New Writers
The Seashell on the Mountaintop is a portrait of a rare genius, Nicolaus Steno, called "the founder of geology" because of his groundbreaking theories on the formation of the natural world. Steno began his career as an anatomist who refused to apply mere deductive reasoning to his experiments, insisting instead on empirical observation: Rather than fitting the facts to preconceived ideas, he adjusted his ideas to fit observable facts. When he applied his method to a mystery that had baffled the top scientific minds of his time -- why were the fossils of seashells found far from the sea? -- he reached a conclusion that would forever alter our understanding of the age of the earth.

In 17th-century Europe, the Church was the supreme authority, and the Old Testament the unquestioned source regarding the timetable of the earth. But for Steno, seashell fossils on mountaintops could be explained only in the context of a world old enough to have produced them, a world millions or perhaps even billions of years old. The most astounding twist in Steno's story was his decision to enter the priesthood just as his hypotheses began to cast doubt on the Bible's veracity as to the age of the earth. In time, Steno would rise to become a bishop, and he ultimately achieved sainthood in 1988. (Summer 2003 Selection)

The New York Times
Cutler's book is marvelous for making one think about what qualifies as an explanation, and for exploring the endless debates that mix strands of partial knowledge with the need to reconcile religious testaments. And it is timely. Nearly half the people in our country today don't accept evolution. Predictably, they have trouble with concepts of the age and structure of the earth, the generation and sequence of its fossil remains, and cosmology itself. For these people, the dialogue between religion and science has not changed much since the 1600's. So both the pious and the impious should find much to ponder in Cutler's account of Steno's times and the fate of his ideas. — Kevin Padian
Publishers Weekly
Science writer Cutler (a contributing editor to The Forces of Change: A New View of Nature) re-creates a fascinating 17th-century world of political and religious upheaval and the progress achieved by curious scientists like the Danish anatomist and (according to Cutler) founder of geology, Nicolaus Steno (1638-1686). A one-time medical student renowned for "his preternatural skill with a scalpel," Steno discovered the parotid gland, which produces saliva, and tear glands. Steno's genius for anatomy provided him the tools to work on the mystery of fossils and the question of how seashells could be found in the rocks of mountains far from the sea. He hypothesized that layers upon layers of earth formed sediments in a sequence, recording a series of events and telling a story about the age of the earth. According to Steno, the stratum at the bottom is the oldest and that at the top is the youngest. Seashells, he said, found their way to mountaintops not by the great biblical flood, as many of his contemporaries believed, but by constant erosion and the sedimentation of soil. Steno published his discoveries in De Solido, after which he abandoned science, converted to Catholicism and spent the last 20 years of his life as an ascetic priest and eventually a bishop. In 1988, he was beatified. Cutler's animated and energetic prose provides a page-turning thriller of scientific discovery, and this splendid biography captures in intimate detail not only its subject but also the tenor of Steno's times. (May) Copyright 2003 Reed Business Information.
Library Journal
At a time when science adhered to biblical parameters, the only possible explanation for seashells found inland and on mountaintops was Noah's flood. Into this world a humble and quiet man named Nicolaus Steno introduced the idea of deep time and laid the foundation for the science of geology in a 78-page volume (best known by its abbreviated title, Prodromus) that remained dormant for more than 100 years. Born in Denmark, Steno was a remarkable 17th-century anatomist-turned-scientist whose studies carried him to Florence, where he became a priest (he was beatified by the pope in 1988). Science writer Cutler, who has a Ph.D. in geology, freely admits that this is not a comprehensive biography (several have been written in Danish, and the other works in English focus on Steno's beatification). Instead, Cutler skims over Steno's accomplishments as an anatomist and priest to concentrate on his work in geology. Like Dava Sobel's Longitude, Cutler's highly readable work compellingly depicts the significant discoveries of a single individual who changed prevailing perceptions. Highly recommended for all academic and larger public libraries.-Gloria Maxwell, Penn Valley Community Coll., Kansas City, MO Copyright 2003 Reed Business Information.
Kirkus Reviews
Natural sciences journalist Cutler crafts a solid biography of 17th-century scientific original and restless religious conservative Nicholas Steno. When, in 1668, Steno produced a little 78-page tome that forwarded the idea of superposition (which eventually became the science of stratigraphy) and went a long way toward explaining just how those shells came to be on mountaintops, he was not coming out of nowhere, writes Cutler. He was already renowned for his discoveries as an anatomist and had been invited by Grand Duke Ferdinand de’ Medici to work at his academy in Florence, becoming an important element in the post-Galilean ascendancy of experimentation and direct observation. Cutler explains how Steno fit into an age of intellectual ferment, doubt, and subversiveness, why he let his research follow its own muse, why neither the realm of eternal forms nor spontaneous generation satisfied him as scientific explanations. As well, Cutler settles Steno on the intellectual timeline that made valuable contributions to earth science, including the work of the Pre-Socratics, the Brothers of Purity, Leonardo, Avicenna, Robert Hooke, and John Woodward (who had an unfortunate tendency toward plagiarism). Cutler handles the scientific material with a sure hand and tackles with eagerness the importance of cross-fertilization as much as conflict in the church/science relationship. And though he is treading in the world of intense emotions when it comes to explaining why Steno took a "blind leap into the infinite" by converting to Catholicism, his comments have the ring of truth because Cutler sticks to his subject’s written words and doesn’t parade his own spiritual notions. Steno’s later years--hevowed poverty and self-denial and died in his mid-40s--play out against church corruption and lay indifference, with science a memory seemingly as distant in time as his fossils. Strong portrait of an unsung innovator, an intellectual meteor that struck the world of geology and sent it slowly spinning. Agent: Jody Rein

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Read an Excerpt


Nothing lasts long under the same form. I have seen what once was solid earth changed into sea, and lands created out of what once was ocean. Seashells lie far away from ocean's waves, and ancient anchors have been found on mountain tops.


The shark was gigantic, but the fishermen managed to haul it ashore. It was still alive and struggling, so to keep it on the beach they lashed it to a tree. Then they killed it. Sharks were common enough off the Tuscan coast, but this was a lamia, a Great White, and it weighed over a ton. When it was safely dead, several of the fishermen reached into the shark's horrible mouth and with their knives gouged out teeth for souvenirs and charms.

Word of the marvel reached the Medici palace in Florence. The Grand Duke Ferdinand II, an aficionado of natural history, ordered that the shark be brought at once so that his court scientists could examine it. But it was too huge, and its flesh had already begun to putrefy. The fishermen hacked off the head and threw the rest of the corpse into the sea. The head was loaded onto a cart to be sent up the valley of the Arno to Florence.

The year was 1666. Florence, indeed all of Europe, was in a state of transition. The Renaissance had pretty much run its course. The Protestant Reformation was a done deal. The Age of Enlightenment, on the other hand, was barely on the horizon. It was an awkward, in-between age - reborn, reformed, but not yet enlightened.

A generation earlier, the Pope had forced Galileo Galilei to renounce his belief in the Copernican theory of the solar system. Galileo had based his opinions on his own observations of the sky, rather than on the Church-approved texts: Aristotle and the Bible. And though he accepted his punishment, he held firm to his convictions about science. True scientific knowledge came from experiments and direct observation of nature, he believed, not from books, even sacred ones. He lived out his final years in Florence, protected by the Grand Duke. Now Ferdinand's court was home to a scientific academy founded by several of Galileo's former pupils determined to keep his spirit alive.

Newest to the group was a diminutive, soft-spoken anatomist from Denmark named Nicolaus Steno. Only 28 years old, he was already famous for his acute powers of observation and his preternatural skill with a scalpel. His discoveries had created sensations in Amsterdam and in Paris, the twin intellectual capitals of Europe. His bold challenges to conventional theories about the heart and the brain had inevitably made him enemies, but also won him many admirers. The Florentine scientists welcomed him as one of their own. When the monstrous shark head arrived in Florence and was brought into the anatomical theater to be dissected, it naturally fell upon Steno to do the honors.

The chance capture of a shark and its dissection by a young scientist eager to prove himself before a prestigious Italian court marked the unlikely beginning to an intellectual revolution that, in its way, was as profound as that of Galileo and Copernicus. Their revolution had shifted the human position in space: It dislodged us as the fixed center of the cosmos and set our world in motion. Steno's changed our place in time. It removed us from the center of the standard Biblical narrative and gave our world a new history. The time encompassed by this new history expanded from a mere six thousand years to nearly five billion. Vastly older than the human species, the world could no longer be claimed as our exclusive domain.

Steno discovered that the crust of the earth contained an archive of its most ancient history. Up until that time, scholars had relied only on the written word - the Bible and the texts of the Ancients - to delve into the past. To the new philosophers of the burgeoning Scientific Revolution, the past had been irrelevant: They were interested in nature's timeless laws, not its historical development. Because no one had ever tried to read the chronicle recorded in the Earth's geologic strata, no one grasped the stupendous changes the world had undergone over its staggeringly long past. But without this perspective, nothing about the forces that shape our physical world - earthquakes, volcanoes, erosion, climate - could ever make scientific sense. The static, mechanical concept of the world had to be replaced by a dynamic, evolutionary one.

This revolution in our understanding of the Earth, triggered by Steno, gathered momentum slowly. Not until the end of the eighteenth century was it in full swing; not until the middle of the twentieth century was it complete. It was resisted as bitterly by scientists as by theologians. It was embraced more readily by Romantic poets than by Enlightenment philosophers. Ironically, the man who launched it never publicly challenged the six-thousand-year Biblical timescale that his science eventually overturned. Yet even in his final years, which he devoted entirely to religion, he never renounced his science either.

The story of Steno is full of such ironies-and of pathos, as well. The genius of his ideas was never fully appreciated during his lifetime. He died young, at 48. At one time a scientist and darling of one of Europe's most lavish courts, he became at the end of his life an ascetic priest. His poverty and fasting, said one friend, had reduced him to "a living corpse."

But that day in Florence he was still at the height of his scientific powers. He had a medical education that, typically for the times, had covered everything from anatomy to astrology. He had the support of a wealthy sovereign. And, most important, he had a mind given to taking unexpected leaps. From the shark, it leaped to a seemingly unrelated question, one that, old as it was, could still generate heated debate. It was not only his answer to this question, but the way he sought to prove it, that triggered the scientific exploration of the world's distant past.


The question was this: Why are seashells often found far from the sea, sometimes embedded in solid rock at the tops of mountains? The ancient Greeks had known and written about these seashells. Medieval theologians had noticed them in the building stones of their cathedrals. Miners and quarrymen found them, as did farmers, shepherds, and travelers. Even the Pope in Rome must have noticed them and wondered, because they littered the slopes of Vatican Hill.

Today we think it natural to say that the seashells were left by a sea that once covered the land. This, in fact, was the explanation offered by the ancient Greeks. The very earliest of the Greek philosophers, the so-called Pre-Socratics, made it the keystone of their various theories of the world, six centuries before Christ. Aristotle continued the tradition, writing that the waxing and waning of the seas were part of the world's "vital process." The land naturally experienced many inundations over the course of time.

Yet most educated people of Steno's time rejected this idea. They thought instead that the shells grew within the Earth. Despite all appearances, the seashells were not actually seashells at all. No clams had ever lived inside the fossil clam shells; no seas had ever covered the mountains.

Bizarre as it may seem today, this idea made perfect sense to the seventeenth-century mind. Some of the more mystical currents of Renaissance thought were still popular, even among those who prided themselves for their rationality. Neo-Platonists and Hermetic philosophers had taught that all things on and within the Earth were shaped by "plastic forces" and invisible emanations from the stars. No one knew how these mysterious forces and emanations actually produced stones in the shapes of seashells, but the world was a mysterious place: No one knew how a magnet's force caused it to attract an iron bar or orient itself toward the north. No one knew how the sun's "emanations" made flowers grow. These things happened in front of the eyes, yet they were still mysterious. Who could say what was or was not possible in the depths of the Earth?

The theory that fossil seashells grew right there in the rocks also had the advantage of sidestepping some thorny problems faced by other explanations. There was, for example, a long tradition among Christian writers that fossil seashells were relics of Noah's flood. The shells were tangible proof of scripture and a visible reminder of God's power and human sinfulness. Missionaries found them useful for demonstrating to the local pagans that the flood described in the Bible had been universal, not something inflicted on the Hebrews alone.

But a closer look at both scripture and fossil seashells led to disconcerting questions. There were contradictions, some easier to reconcile than others. The shells resembled species that lived in salt water, but forty days and nights of rain would have made a freshwater flood. And how could so many shellfish become spread so widely in a flood that, according to the Bible, lasted no more than a year? Medieval monks had felt free to fudge a little in their reading of the text. Maybe it was the overflowing sea that caused the flood, not rain, as was written. Maybe it had lasted somewhat longer than the text said. It was a respectable practice. Saint Augustine and the other early church fathers had not hesitated to interpret scripture metaphorically when necessary.

There was another, stickier, problem, though, one that metaphors couldn't easily solve. The Bible said God created the solid Earth and gave it its form in the very first week. Noah's flood happened much later. How, then, how did seashells get inside rocks, which had supposedly already been created when the flood took place? The flood might have left shells on mountains, but not in them.

Of course, it was possible to call them a miracle, and leave it at that, but the budding scientific minds of the seventeenth century were reluctant to do this. They wanted to explain the world by natural law whenever possible. And since the Reformation, metaphorical interpretations of Scripture had become increasingly frowned upon, too. Luther and Calvin had put the Bible at the center of their faith; the plain meaning of its words were not to be trifled with.

Even the "vital processes" suggested by Aristotle offered no way out of the dilemma. It may have been a perfectly acceptable explanation for low-lying shell deposits near the coasts, but for the shells in the mountains, it could lead to dangerous ideas. Aristotle had emphasized the slowness of geographical changes. In the time it would take for an ocean to dry up, or a mountain to sink beneath the waves, whole nations might arise and perish. He imagined an eternal world-as many pagans of his time did-which put no limits at all on time, and he claimed that these natural inundations occurred again and again over the ages. For the modern seventeenth-century man, this simply could not be true. There was not enough time. Nothing of the sort had ever been seen in all the centuries of recorded history. Mount Sinai still stood as high as it had when Moses brought down the Ten Commandments. The Mediterranean Sea had not dried up appreciably, either. How, then, could geography have been overhauled many times when the world itself was known to be less than six thousand years old?

The evidence for this time limit came from the Bible, which was supposed to contain a complete history of the world. By tallying all the generations and reigns of kings recorded in its pages one could estimate the total time elapsed since Creation. The answers varied, depending on which version of scripture that one used, but none exceeded six thousand years. The most definitive and precise was the one calculated by James Ussher, the Anglican Archbishop of Armagh, Ireland.

Ussher was one of the most formidable scholars of his time; it was said that his personal library was the largest in all of western Europe. He devoted his life to compiling his chronology. The date he gave for Creation was Sunday, October 23, 4004 B.C. When he died in 1656, a year after his book was published, the world would have been 5,660 years old, by his reckoning. And he believed, as did many others, that the world was not likely to get much older. Six thousand years would be the limit for the world's total life span.

This was also revealed in the Bible, whose words were assumed to be not only history, but prophesy. The six days of Creation in Genesis foretold that the world would exist for six ages. How long was an "age"? The Bible revealed this, too. "In Thy sight, O Lord," it read, " a thousand years are as one day." Six thousand years, then, was all the time there would ever be.

For a Christian, the world could not be eternal because only God was eternal. To say that the world was eternal denied that it had a beginning, that it had been created by God, indeed that it had been created at all. People were eternal, too, in the cyclical view of time. This raised all kinds of problems. If a person could borrow money in one cycle, and repay it in the next, which some pagans saw as a perfectly acceptable practice, then where was the urgency for a sinner to reform and repay his debt to God? And the whole idea of salvation was thrown into question if the birth, crucifixion, and resurrection of Christ were not unique events in time, but happened again and again ad infinitum. "God forbid that we should believe this," wrote Saint Augustine, "For Christ died once for our sins, and rising again, dies no more."

The Bible plainly said that the world was created, not eternal. Genesis gave the story of how it happened. Some people, including Saint Augustine, allowed that the six days of Creation were probably metaphorical - although Saint Augustine thought that six days were too long for an Almighty God who could create a universe in an instant if he wanted to. But even if one was willing to add a little slack to the Creation week, the history of the world still had to be finite. Time went in one direction, it did not loop around, it had a beginning and an end.

Given the difficulty of explaining fossil seashells in a six thousand-year-old world, and the repugnance of the only apparent alternative, Aristotle's eternal world, the idea that the fossils grew in place was understandably attractive. The flood still had its advocates - Martin Luther notably among them - and a few daring souls even dared to openly support the eternalist solution. But to argue that the seashells actually were seashells was to swim against some strong religious and scientific currents.

This, of course, is what Steno would do. And, along the way, he would offer his ideas on the growth of crystals, the erosion of land, the growth of mountains, and, most famously, the laying down of sedimentary strata. What gelled in his anatomist's mind was a scientific approach to the anatomy of the Earth, how its parts grew and how their development could be understood. It was, in effect, a new science, sprung almost fully formed from the mind of one man.

There was no science of the Earth's history at the time, because the Earth was not really considered to even have a history. People had a history; not things, not nature. For the orthodox Christian, each part of the world had been created in an instant, more or less in its present form. There was no point in asking how mountains or valleys formed. They had just been created. No further explanation was necessary or even possible. If someone allowed that there had, in fact, been a few changes since Creation, these were seen as inherently chaotic. Changes could only mean the decay of God's originally perfect Creation-changes for the worse, by definition-and so not worthy of Christian contemplation. And, finally, all important events in the six thousand years since the beginning of the world were recorded in the Bible, anyway. There was no need for any further investigation.


Unlike his contemporaries, however, Steno found not chaos but order in the crust of the Earth. It wasn't the perfectly regular order that astronomers found in the heavens, or the mathematical order that physicists found in pendulums and projectiles. It was the order of a well-told story, a narrative in which one part follows another with inevitable logic, but the conclusion is not predictable. He found the logic by which the faulting, uplift, erosion, and stratification of a landscape and the bedrock beneath it could be put into an intelligible sequence. From the narrative he read in the rocks, he could write a history of the landscape. And the logic, if extended, could reveal the history of the entire world.

The backbone of his system was a simple but tremendously powerful idea. Recognizing that the layers of rock that entombed fossil shells were made by the gradual accumulation of sediment, he realized that each layer embodied a span of time in the past. He saw no way to measure the number of years or centuries involved, and was loathe to speculate, but it was clear that the layers, one on top of the other, formed an unambiguous sequence: The lowest layer had been formed first, the highest last. Depending on their fossils and their sediments, the layers recorded the succession of seas, rivers, lakes, and soils that once covered the land. Geologists call Steno's insight the "Principle of Superposition." It means that, layer by layer, the history of the world is written in stone.

Just as Galileo's telescope had opened up space to science, Steno's strata opened up the past. In an astonishing feat of intellectual focus, Steno produced his seminal geological work in a period of less than two years; two years in which his personal life also underwent major upheavals. Equally remarkable, his new science is outlined in barely 100 pages of text and just a handful of diagrams. His 78-page masterpiece De Solido (On Solids), was originally intended as an abstract, a "prodromus," of a longer and more detailed dissertation. But that work never materialized. De Solido was his last published geological work. A few years later he entered the priesthood and gave up scientific research altogether. While in Italy he had made a controversial switch from Lutheran to Catholic, and with the zeal of a new convert he devoted the remainder of his life to the Church.

Steno's singular approach to science made him something of an enigma to his contemporaries. His abrupt retreat from it has made him an enigma to many who have studied him since. He had a mind that was extraordinarily fertile, but extraordinarily restless. And just as he overturned many assumptions about science, history, and faith cherished in his own time, his story overturns many that are equally cherished in ours.

-Reprinted from The Seashell on the Mountaintop by Alan Cutler by permission of Dutton, a member of Penguin Group (USA) Inc. Copyright © Alan Cutler, 2003. All rights reserved. This excerpt, or any parts thereof, may not be reproduced without permission.

Meet the Author

Alan Cutler has a Ph.D. in geology and is a writer affiliated with the Smithsonian Institution. Dr. Cutler was a contributing editor to the book Forces of Change: A New View of Nature, a joint publication of the Smithsonian and the National Geographic Society; contributors included Stephen Jay Gould, John McPhee, and David Quammen.  Dr. Cutler’s writing has also appeared in The Washington Post and The Sciences, among other publications.

Brief Biography

Gaithersburg, Maryland
Date of Birth:
February 24, 1954
Place of Birth:
Bethesda, Maryland
B.A., Carleton College, 1975; M.S., University of Rochester, 1977; Ph.D., University of Arizona, 1991

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