The Rocks Don't Lie: A Geologist Investigates Noah's Flood

by David R. Montgomery

  If we consider attentively the facts that respect the Siberian fossil bones, there will appear insurmountable objections to every theory that supposes them to be exotic, and to have been brought into their present situation from a distant country… . Shall we ascribe it to some immense torrent, which, sweeping across the desarts of Tartary, and the mountains of Altai, transported the productions of India to the plains of Siberia, and interred in the mud of the Lena animals that had fed on the banks of the Barampooter or the Ganges? Were all other objections of so extraordinary a supposition removed, the preservation of the hide and muscles of a dead animal, and the adhesion of the parts, while it was dragged for 2000 miles over some of the highest and most rugged mountains in the world, is too absurd to be for a moment admitted.6

  Playfair further noted how their carcasses would surely have rotted if these great beasts had died in a tropical climate. Whatever they were, mammoths were not relics of the Flood.

  By the close of the eighteenth century, theologians had begun to recognize the lack of a unified explanation among natural philosophers for Noah’s Flood and the age of the world. The wide range of conflicting theories and interpretations fostered suspicions that perhaps it was the Bible that was being misinterpreted. The floodgates of heaven and the fountains of the deep had been interpreted to refer to comets, a great vapor canopy, water from alpine caves, and a vast subterranean sea—just about everywhere one might imagine finding enough water to drown the world. Theologians started to question whether scripture was meant to be a source of scientific information as well as a book of personal and moral redemption. Even conservative Christians began to question whether Noah’s Flood was all there was to earth history.

  It is impossible to stand at Siccar Point and reasonably see how to fit what you can read in the rocks into just 6,000 years of time. When Roman ruins still stand after 2,000 years, how could raising and eroding off two mountain ranges happen in just twice as long before that? The virtually unimaginable amount of time required to form the two unconformable sandstones exposed along the Scottish coast offers a humbling glimpse of the infinite.

  Hutton’s recognition of the concept we now call deep time laid the foundation for a new geological time scale. It was a turning point in our story and a huge development for the field of geology. Reinterpreting the days of the week of Creation as geological ages allowed earth history to accommodate vast expanses of geologic time. After all, who knew how long one of God’s working days lasted? Perhaps the rock record paralleled Genesis—if interpreted as consisting of six ages rather than six days. Maybe Moses only wrote about the part of the Flood that Noah witnessed. Although biblical interpretations were being reconsidered, there was still general faith that the rocks filled in the real story.

  Then, as now, conventional wisdom guided interpretation of discoveries to the extent it could. Scientific revolutions happen when conventional views can no longer bend under the weight of new findings. Natural philosophers were still looking to prove Noah’s Flood because they viewed the world through the filter of religion, not because they feared theological condemnation. Despite the evidence Hutton and company marshaled to frame the geological story, natural philosophers were reluctant to abandon the biblical story. Only later did science start to modify and seriously undermine faith in biblical truth. Even so, it had become clear there was more to earth history and fossils than simple deposition of sedimentary rocks from a single flood over the span of a single year.

  Soon geologists would unearth compelling evidence for multiple catastrophes, each of which ended a distinct period of earth history. As nagging questions and alternative ideas began to reshape how Christians interpreted the story of Noah’s Flood, natural philosophers shifted gears in looking for geological evidence of it. The search for Noah’s Flood moved from rocks into the overlying deposits of unconsolidated sediments that lay scattered across Earth’s surface.

  7

  Catastrophic Revelations

  BEFORE THE EARLY NINETEENTH CENTURY, natural philosophers paid little attention to deposits of loose gravel, sand, and boulders lying above solid rock. But northern Europe’s geological blanket of unconsolidated material became far more interesting once it was thought that the part of earth history that overlapped with human history was preserved in surficial sediments rather than in the solid rock below. It helped that geology arose as a science in countries that had been glaciated, where a regional cover of glacial deposits—gravel, sand, boulders, and mud—resembled what you might expect a big flood to leave behind. These surface deposits and topography, the form of the land itself, became the link between the modern world people knew and the former worlds preserved in the rocky depths of geological time.

  I came to appreciate the potential for catastrophic rearrangement of surficial deposits in the Philippines. At the time, I was doing fieldwork in the Pasig-Potrero River, where one of my graduate students was studying changes after the catastrophic 1991 eruption blew the top off Mount Pinatubo and buried the surrounding countryside under hot pumice and ash. The whole landscape around the volcano changed, as river valleys filled in with sediment only to have great canyons cut back down hundreds of feet into the loose debris in just a couple of years. We saw the Passig-Potrero River as an ideal place to study how rivers behaved when supplied with as much sediment as they could carry.

  On a beautiful tropical morning, we started out from Delta 5, an abandoned military checkpoint perched on a rock outcrop sticking up from the riverbank. We headed upstream, leaving the coastal plains to enter the volcanic upland. Walking up the riverbed, we surveyed it in three-hundred-foot sections. One person would stay behind, sighting through a tripod-mounted level, as another took our stadia rod—a giant collapsible ruler—out to the end of a long tape measure. Using the level to read off the elevation every few feet as we moved the stadia rod along the tape, we measured the elevation of the riverbed. Repeating the survey over a number of years gave us a record of how the river ate down into the volcanic debris as lahars—volcanic mudflows—surged downstream to bury villages and towns beneath a blanket of sediment.

  Just before lunch we noticed that an ominous black cloud had settled in over the volcano several miles upstream. The river started rising as we kept surveying our way up through a tight canyon. When the flow got deep enough to start moving the riverbed, grapefruit-sized rocks rolled into our shins and we decided to break for lunch on a sand terrace five or six feet above the water level. About halfway through lunch we noticed the water rising even faster. As the river started lapping up onto our lunch-stop terrace, we retreated to the foot of the canyon walls and watched six-foot-high waves cascade down the river we had walked up all morning.

  Map of the Philippines showing location of Mount Pinatubo and the Pasig-Potrero River draining off the volcano’s eastern flank.

  Alarmed, we climbed up through narrow side channels that had cut down through the volcanic debris—the only other way out of the canyon. By the time we reached the top of the side canyon we could see our lunch spot, several hundred feet below, submerged beneath a roaring torrent of bouncing boulders. We perched for the afternoon, trapped on the ridgetop but enthralled by walls of water crashing down the canyon. Here in front of us was a graphic illustration of what had drawn me to geology in the first place: Earth’s appearance of being stable—of being solid as a rock—only held some of the time.

  In the early nineteenth century, the conventional view was that grand catastrophes reshaped landscapes in a geologic jiffy. The idea that the slow pace of everyday change could shape and reshape the world was considered delusional fantasy. By the end of the century, geologists believed that everyday erosion was how the world worked, and grand catastrophes had become geologically taboo.

  Scientific curiosity and religious conviction were not alone in pushing efforts to better understand regional geology. Just as demand for iron and coal drove advances in mining and mineralogy, construction of railroads and canals created a need to un
derstand regional geology. As necessity and practical interest grew, schools in industrializing areas began to appoint professors of geology. Studying rocks could be more than just an inspired hobby for those with the time, means, and inclination to seek insight into nature’s inner workings. It could be a livelihood. As geologists began to work out the details of local and regional geology, they reassessed the role of Noah’s Flood in earth history.

  In 1815, surveyor and canal builder William Smith worked out the structure of England’s layered rocks in compiling what is widely credited as the first regional geologic map. He carefully documented a consistent, well-ordered succession of rock types across England that was far too systematic to have formed during the chaos of a globe-wrecking deluge. Smith also showed that different layers of rock consistently held different fossils. Based on observations collected over years of field excursions, Smith’s carefully compiled map allowed him to accurately predict the type of rock and the fossils in it virtually anywhere in England. His obsession with perfecting his map bankrupted both himself and the idea that a single catastrophic flood deposited layered rocks. After he published his map, geologists no longer looked for Noah’s Flood in the rocks. Instead they looked for signs of a great flood in topography and surficial deposits.

  Across the English Channel, Smith’s contemporary Georges Cuvier, the vertebrate paleontologist who had dismissed Scheuchzer’s flood victim and concluded that mammoths were extinct, was busy mapping the rocks in the countryside around Paris. He found a sequence of distinctively terrestrial rocks containing fossil quadrupeds that alternated with layers full of fossil seashells. He knew that a single flood could not produce a thick sequence of interlayered terrestrial and marine rocks. Clearly, the sea inundated the land not just once but time and time again. Further fieldwork in the Paris basin unearthed evidence for alternating periods of fresh and saltwater inundation that Cuvier interpreted as evidence for at least half a dozen great floods, each of which ended a geological era. Instead of Hutton’s grand engine of slow change, Cuvier’s 1813 Essay on the Theory of the Earth concluded that each catastrophe recorded another transition in a long series of geological eras. Ever since, these two views of geologic change—slow and steady versus catastrophic—have framed competing theories for how the world is shaped.

  The idea that a catastrophic biblical flood could have remodeled the European landscape was vividly reinforced in 1818, when the Getroz glacier dammed the river Dranse in Switzerland’s Val de Bagnes. Advancing like the glacier that dammed the Tsangpo in Tibet, the ice blocked the river and a lake holding eight hundred million cubic feet of water formed above the frozen impoundment. When a tunnel was cut through it to draw down the lake, the ice and debris dam failed, sending a wall of debris-charged water surging down the valley at more than thirty feet a second. The flood swept away landmarks as sand and mud filled the local church to the pulpit. Huge boulders lay strewn around the fresh deposits. As residents dug out from the mess, they discovered trees and houses swept away in the torrent. The event impressed natural philosophers with how catastrophes could blanket large areas under sediment. Here, perhaps, was an analog for the geological signature of really big floods. The deposit left by this modern catastrophe looked a lot like the blanket of sand, gravel, and mud that covered much of northern Europe.

  Again, Cuvier led the way in elaborating the power and dynamism of geological processes in his 1825 Discourse on the Revolutions of the Globe. He made the case that distinctive animals lived during different epochs of earth history and described how abrupt discontinuities between geological formations with different fossil assemblages testified to periodic catastrophes having remodeled the world. In his view, the most recent catastrophe was a sudden flood that separated the relatively short history of humanity from the depths of geologic time. Cuvier’s contention that one could not explain the geologic record solely by means of existing causes—that the processes that shaped Earth’s surface were different in the past—became known as catastrophism, and stood in direct contrast to Hutton’s articulation of how things happened gradually through many small changes, a view that became known as uniformitarianism.

  Cuvier’s idea of periodic cataclysms seemed to address otherwise perplexing observations. His compelling evidence for the repeated destruction of former worlds inspired geologically literate clergy to reinterpret Genesis. As early as 1816 the Stackhouse Bible cautioned readers, “Moses records the history of the earth only in its present state… . There is nothing in the sacred writing forbidding us to suppose that [fossils] are the ruins of a former earth.”1 Fossils now belonged to numerous ancient catastrophes. Geological evidence was starting to shape biblical interpretation.

  A prominent Protestant, Cuvier did little to counter the impression that the most recent of his long series of grand catastrophes was the biblical flood. He asserted it could not have been all that ancient: “If there is any circumstance thoroughly established in geology, it is that the crust of our globe has been subjected to a great and sudden revolution, the epoch of which cannot be dated much farther back than five or six thousand years ago.”2 He thought that a small number of people and animals survived the most recent cataclysm, about the time conventionally ascribed to Noah’s Flood.

  Those seeking geological support for the biblical flood now looked to the sediments on top of the rocks, assuming Noah’s Flood was a more recent catastrophe than the geological revolutions recorded in hard rock. The most influential nineteenth-century diluvialist was William Buckland, a minister in the Church of England and Oxford’s first professor of geology. He passionately defended the traditional view of Noah’s Flood but acknowledged that the six days of Creation could not be taken literally. The son of a clergyman, Buckland knew that geology would instantly become a respectable science if he could show that it validated the Genesis flood.

  A man of his times, Buckland straddled both worlds—those of the church and field geology. He wanted to forge links between human history as recorded in classical texts and biblical stories and earth history as revealed by geology. Like many of his contemporaries, he believed that Moses disregarded most of earth history because it did not concern mankind.

  Confident of the reality of Noah’s Flood, Buckland saw its signature in the sculpting of topography and the geologically recent deposition of the blanket of gravel covering much of Britain. He saw geological evidence as supporting the universality of the Deluge. What else could explain the giant out-of-place boulders in northern Europe from Norway to the Alps? Made of rock with no local source, boulders the size of barns had obviously been transported from distant sources. A really big flood seemed like the only reasonable way to explain how to move huge rocks. Lacking reasonable alternatives, Buckland and his contemporaries attributed the deposition of the gravel blanket and transport of enormous boulders to great waves during the biblical flood.

  In his 1819 inaugural address at Oxford, Buckland equated Cuvier’s most recent catastrophic inundation with Noah’s Flood.

  The grand fact of an universal deluge at no very remote period is proved on grounds so decisive and incontrovertible, that, had we never heard of such an event from Scripture, or any other, authority, Geology of itself must have called in the assistance of some such catastrophe, to explain the phenomena of diluvian action which are universally presented to us, and which are unintelligible without recourse to a deluge exerting its ravages at a period not more ancient than that announced in the Book of Genesis.3

  Although the remains of modern species buried in the surficial gravels pointed to a recent calamity, Buckland did not believe that Noah’s Flood formed fossil-bearing rocks. To find evidence of the Flood you had to look in the overlying unconsolidated sediments and at the lay of the land, the form of topography.

  In Buckland’s opinion, Europe’s surficial gravel was too extensive to have been laid down by rivers. He thought the Flood simultaneously deposited it and carved the modern landscape from older rocks. Buckland coined the
term diluvium to describe the surficial deposits that mantled much of northern Europe and to distinguish them from alluvium, the sand and gravel laid down by modern rivers. He remained disturbed, however, that no human fossils had been found in diluvium. Where were the bones of those the Flood was sent to destroy?

  Despite this troubling detail, Buckland stressed that geological facts were broadly consistent with the biblical account because Noah’s Flood ushered in only the most recent of a long succession of worlds. Buckland’s lecture, published as Vindiciae Geologicae; or, the Connexion of Geology with Religion Explained, argued that geological facts “are consistent with the accounts of the creation and deluge recorded in the mosaic writings… . The evidences afforded by Geological phenomena may enable us to lay more securely the very foundations of Natural Theology.”4

  The “Natural Theology” to which Buckland referred followed William Paley’s popular and influential 1802 book of the same name. Paley argued that scientific revelations contradicting biblical interpretations provided natural guidance for better interpreting scripture because the Bible and the book of nature shared the same author. In the opening decades of the nineteenth century, even Pope Pius VII endorsed viewing the six days of Creation as of indeterminate length rather than as a literal week of twenty-four-hour days. A little more than a decade after publication of Paley’s popular book, in 1813, English geologist Robert Bakewell sought to reconcile the geological and biblical chronologies in his Introduction to Geology, the first geological textbook published in English, arguing that the Mosaic chronology began when the world became fit for human habitation.

  Others argued that a long time passed between the initial Creation in the first verse of Genesis and the formless Earth of the second verse. Perhaps the time between when God created the world long ago and when he remodeled it for human use wasn’t recorded in the Bible, leaving an indeterminate gap between the first two verses of Genesis. The gap theory, as this idea became known, provided an alternative to the day-age theory that each day of creation lasted far longer than twenty-four hours.