‘Small Earthquake in Chile, Not many dead.’ The journalist Claud Cockburn supposedly won a prize for dreaming up this notoriously dull newspaper headline, although it seems never to have been used. In contrast, the very real Valparaiso earthquake of 19 November 1822 was immensely newsworthy: it killed or injured around 500 people, razed entire villages to the ground and prompted a tsunami. One on-the-spot eye-witness, Maria Graham, described how a 100-mile stretch of coast had been lifted several feet above its former level so that ‘the ancient bed of the sea laid bare and dry, with beds of oysters, muscles, and other shells adhering to the rocks on which they grew, the fish being dead and exhaling most offensive effluvia.’

The earthquake lasted for five minutes, but its aftershocks reverberated through the quiet meeting rooms of London’s Geological Society for several years. During a series of vituperative debates, repressed rivalries erupted into open hostility. Although this natural catastrophe strongly supported one of two competing theories, it was not immediately accepted as clinching evidence. The animosity between two leading experts was inflamed by the question of the report’s reliability – could a woman’s observations really be trusted?

Neptunists vs Plutonists

One of geology’s most controversial debates emerged from a learned controversy about French basalt. In a joke that must have seemed funny at the time, two opposing factions were mocked as ‘Neptunists’ and ‘Plutonists’, named after the Roman gods who ruled over the sea and the underworld; these labels stuck, even featuring in Goethe’s Faust.

By the end of the 18th century it had become clear that the account of creation given in the Bible could not be interpreted literally. Most geologists accepted not only that the earth was far older than the traditional figure of 6,000 years, but also that it had undergone substantial changes over the millennia. A major school of thought, Neptunism was developed in Germany by Abraham Werner, who examined rock formations in mines. According to Werner, the terrestrial globe had originally been made of water; eventually, suspended particles coalesced into solid rocks, forming the continents and settling in layers embedded with fossils.

This theory was challenged by James Hutton, a Scottish agriculturalist who insisted on the overriding importance of volcanoes and earthquakes for rock formation. Extending the age of the earth way, way back in time, he outlined a Plutonist explanation that stressed the significance of great upheavals deep inside the earth leading to the elevation of vast mountain ranges. For adherents to this type of model, volcanic rocks are worn away by erosion and weathering, depositing debris on the seabed that is gradually lifted and moulded into new configurations by heat and pressure.

Plutonists recognised the role of water in laying down sedimentary rocks such as limestone, but they definitively confirmed their volcanic case by analysing basalt. However hard the Neptunists scrutinised different samples, they could find no fossils trapped inside this hard, crystalline material that was insoluble in water. Strengthening the Plutonist position still further, Hutton pointed to his local Edinburgh cliffs, which were shot through with bands of basalt that appeared to have been pushed up as molten lava from beneath the surface of the earth.

A widow in Chile 

Marginalised as a woman and an outsider, Maria Graham (1785-1842) unexpectedly intervened in these gentlemanly debates and disrupted London’s geological community. She was the first woman to have a report of her own published in the Transactions of the Geological Society, but, as if still ostracised, she has received surprisingly little attention from historians. That might be because she was not professionally trained – but neither were many men interested in rocks and minerals. There were neither entry qualifications nor university degrees for practising geology. Like her male peers, Graham was a meticulous observer who discussed her findings with eminent colleagues, sending them drawings and specimens of plants, rocks and insects that she collected during her frequent trips abroad.

A perpetual traveller and prolific author, Graham married her first husband in India, soon embarking on a career as a travel writer, publishing two books about the country. As the wife of a naval officer, she spent long periods alone – but, unusually, she refused to embrace domesticity. Instead she worked independently, engaging in the female speciality of translating as well as indulging her passion for art by living in Italy and writing about Nicolas Poussin.

In 1821 Graham set off across the Atlantic on a ship commanded by her husband, but he died during the voyage of a fever. Landing alone in Chile, she refused to return, instead staying on for a couple of years to produce a book that included a full version of her report on the Valparaiso earthquake. Although she did eventually decide to go back to England, she first paid a visit to Brazil, returning there to tutor the emperor’s young daughter – and also to generate yet more travel literature. Some years later she married a man who also loved exploring. Though their travels were curtailed after she suffered a disabling illness, she continued to research and to write.

Competing theories 

No immediate fireworks erupted when Graham’s short report of the Chilean earthquake reached the Geological Society, but a decade later the controversy escalated to the academic equivalent of pistols at dawn. The Society’s founder, a lawyer called George Bellas Greenough, used his presidential address to denounce Graham’s credibility and deny the validity of her observations. But she was not his main target: his anger had been provoked by the public success of another geological lawyer, his rival Charles Lyell.

Lyell had just published the third and final volume of Principles of Geology, which dramatically extended the age of the earth and encouraged Charles Darwin to develop his theory of evolution by the protracted processes of natural selection. Even more radical than Hutton, Lyell was a committed Plutonist who abandoned the biblical concept of a single creation to introduce a cyclical model. Conventionally, time resembled an arrow flying inexorably onwards from a definite beginning, so that the future could never be the same as the past. Instead, argued Lyell, we live in a universe that is slowly changing at a constant rate. In repetitive patterns, the mountain ranges of today may gradually become the ocean floors of tomorrow, before eventually rising up again to dominate the landscape.

To support this sophisticated theory, Lyell gathered evidence from all over the world. However, describing earthquakes proved a problem: as he explained, reports overwhelmingly focused on ‘the number of human beings who perished, the number of cities laid in ruins, the value of property destroyed’. So he was delighted to discover Graham’s account, which was packed with geological information. Referring to her by name, Lyell commented on her findings at considerable length, quoting relevant comments that supported his own, such as:

Mrs Graham observed …several older elevated lines of beach … extending in a parallel direction to the shore, to the height of fifty feet above the sea.

Lyell pointed out that during only a few hours, 100,000 square miles of Chile had been lifted up several feet. Despite the evidence, Greenough flatly refused to accept that observation as fact. He fell back on attacking Graham, although he only mustered up flimsy arguments. Leaning towards a Neptunist view, Greenough simply denied that land could be raised by the powerful eruption of igneous rocks; bizarrely, he maintained that since there was no viable explanation for sudden elevation, it could not happen. Instead, he posited ‘a chronic and almost imperceptible impulsion of land upwards’ caused by water that had seeped into underground cavities caused by volcanoes.

Credit due 

Graham defended herself robustly, emphasising Greenough’s ‘unjust insinuations, selective omissions of important details, errors and inconsistencies’. She was also backed by the global geological community, who judged that this episode had provoked ‘so much, at times too acrimonious controversy’. Darwin was so supportive that when the Beagle reached Chile, he made a special expedition to see for himself Graham’s ‘great beds of shells’ lifted up above the level of the ocean. In 1835 another earthquake struck the area and permanently raised the land. This time, trained male observers were present – and at last, Graham was definitively vindicated.

Patricia Fara is an Emeritus Fellow of Clare College, Cambridge. Her most recent book is Life after Gravity: The London Career of Isaac Newton (Oxford University Press, 2021).