The Maastricht Animal, as it was first called, played a significant role in the death of religious dogma in Europe and the advance of biological and paleontological science.
"Hidden History" is a diary series that explores forgotten and little-known areas of history.
A Mosasaurus skull
.
As every schoolboy knows, much of the Netherlands is below sea level, and has been reclaimed by building a series of dikes and pumping out the sea water. One of the few high spots in the area, though, is Mount Sint Pieter (“Saint Peter” in English) near the town of Maastricht, part of the Caestert Plateau about 200 miles south of Amsterdam near the Belgian border.
Although this hill sits about 560 feet above the sea, it too was once part of the sea floor, and it consists of a deep layer of limestone, chalk and marl some 500 feet thick. Like the more famous white cliffs of Dover in England, the sediment under Mount Sint Pieter is late Cretaceous in age (it would give its name to the geological Maastrichtian Stage, which is slightly younger than the Dover deposits).
In prehistoric times, chalk would have been a good place to look for flint and other useful rocks, and there are indications of Stone Age mines and burials in the surrounding area. Such a prominent high point on a flat low landscape would also have had substantial military value, and archaeologists have found evidence of an Iron Age fort here which was built around 500 BCE. When the Romans arrived in the 1st century BCE (led by Julius Caesar), they began mining the limestone as a building material, and dug a number of tunnels into the hillside. During the medieval period, these quarries were expanded, and eventually grew to some 20,000 tunnels extending for over a hundred miles under what is now the border with Belgium. A series of castles were built on the mountain, with old ones periodically abandoned and replaced by new.
By the 17th century, the Netherlands had become a battleground, with periodic invasions by France, Spain and Austria. After the French attacked Maastricht in 1673, the Dutch erected Fort Sint Pieter atop the mountain. This was a pentagon-shaped fort, typical of the time, which had a central courtyard surrounded by thick low walls and bastions that allowed cannons to fire in all directions.
The Fort was never taken in combat, but by the middle of the 18th century it had become outdated and was vulnerable to newer artillery, and its military importance faded. But the population of Maastricht was growing, and one of the things it needed was stone for buildings. The limestone deposits at Mount Sint Pieter offered a ready source, and new quarry tunnels were opened.
It would lead to an important scientific discovery.
At this time, fierce debates were raging among the educated classes of Europe. For centuries, religious authorities, both Catholic and Protestant, had asserted that the Earth was approximately 6,000 years old (calculated from all the “begats” in the book of Genesis), and that it had been created by God in six days in the form that we see today. People had of course always been finding fossilized bones in the ground (the Greek philosopher Xenophanes had long ago explained that fossil fish skeletons found on mountains proved that those lands had once been under the sea), and by the 1670s most educated people accepted that fossils were indeed the remains of once-living creatures.
Theologians were able to adapt to this idea, with many of them asserting that “fossils” must be the remains of those creatures which had been drowned and buried in the Biblical Flood of Noah. But when some naturalists began to assert that some of these fossils were from animals that were “extinct”—which had previously existed and had all died out—the theologians balked. God’s Creation, they argued, had been “good”, every animal was a part of the “Great Chain of Being”, and the idea that parts of this “chain” had completely disappeared implied (blasphemously) that God’s Plan was somehow not “perfect”. Even as more and more fossils appeared which were apparently different from living animals, religious authorities were able to explain them away by asserting that they were either misidentified remains of known animals, or that they were in fact still alive today, living in remote and unexplored parts of the world.
The argument over “extinction” came to a head (literally) at Fort Sint Pieter.
In 1764, the tunneling miners were stumped to find a number of large bones embedded in the limestone. But the biggest mystery of all came in 1780, when a monstrous nearly-intact skull, studded with teeth, was found. Although they had no way of knowing it at the time, the skull was 66 million years old.
At the time, Maastricht was a scientific backwater and it lacked a museum. The skull was taken to Johann Hoffmann, a local surgeon and amateur fossil collector, but he did not know what to make of it. Other local naturalists were also utterly baffled by the immense skull.
It took several years for rumors of the strange find to disperse out into the rest of Europe—mostly through letters written by Hoffmann. But when the French again invaded the Netherlands and captured Maastricht in 1794, they had heard enough about the “Maastricht Animal” to be interested in it, and the entire skull and other bones were seized as war booty by French troops and sent to Paris as part of a shipment numbering over 150 crates, all of it looted. There, the skeleton was taken to the premiere anatomist in the world at the time, Georges Cuvier in the National Museum of Natural History.
Cuvier had virtually single-handedly founded the discipline of “comparative anatomy” and had already established his reputation as the leading scientific mind in Europe. By carefully comparing the structure of fossil bones with those of living animals, Cuvier was able to demonstrate that, for instance, Mammoths and Mastodons were relatives of living African and Asian Elephants—but were different from both “as much as, or more than, the dog differs from the jackal”. In one memorable incident, Cuvier had been presented with a half-uncovered fossil that had been dug out of a gypsum mine near Paris and confidently declared that it was a marsupial—something that had never been found in Europe. To prove it, he predicted that one of the rock-covered areas of the skeleton should exhibit a pair of bones called “epipubics”, found only in marsupials. Then, in a public lecture, he carefully scraped away the rock matrix—and triumphantly revealed the epipubics, right where he had said they would be. Awestruck admirers said of him that he could accurately reconstruct an entire animal just from one of its teeth.
Although Cuvier had an open mind on the question of “extinction”, he preferred to believe that animals like Mammoths were still alive, somewhere in the vast unexplored areas of Asia and the Americas.
Now, Cuvier carefully studied the enormous skull from Maastricht. He methodically examined each bone and tooth, noting its size, shape, and features. He then undertook a detailed comparison with sample bones from the museum’s collection. His first thought was that the skull belonged to a large whale, but comparison with whale skeletons showed significant differences. Then he considered the idea that it might be a giant crocodile. But once again, the bones and teeth did not match.
Finally, after over a decade of work, Cuvier found his answer. The bones of the skull and, especially, the teeth, most closely resembled those of a reptile—specifically, they were very similar to living Monitor Lizards. The only significant difference was the size—and that was crucial. Living Monitor Lizards average a few feet in length, and the largest living lizard (the Komodo Dragon—which was still unknown in Cuvier’s day) is around ten feet long. The complete Maastricht skeleton, Cuvier was able to estimate, would have been at least 40 feet long (the skull alone was five feet in length—by itself longer than most living lizards).
It completely changed Cuvier’s mind. From the limb bones that were found with the skull, Cuvier could tell that the Maastricht Animal was an aquatic animal, and from its teeth he concluded that it ate fish. There were no large predatory marine reptiles currently alive, Cuvier knew, and he concluded that it was simply impossible that such an immense beast could inhabit today’s seas without being known. The skeleton, he concluded, must be the remains of an ancient animal that no longer existed. It was “extinct”. He gave the creature the Latin scientific name Mosasaurus (“the lizard from Meuse”), after the Meuse River that flowed near Maastricht.
Cuvier laid out the results of his investigation in 1808, in a paper that was published in 1812 as part of a collection titled Recherches sur les ossements fossiles (“Research on Fossil Bones”). He had been studying the skeleton for fourteen years. By this time, further fossils had been found, particularly in the Americas and in England, which also hinted at animals that no longer existed—giant ground-dwelling sloths, flying pterosaurs, and more huge aquatic reptiles like ichthyosaurs and plesiosaurs. But it was the Mosasaurus which clinched the case. By the 1820s, virtually every naturalist in Europe had become convinced: there really had been an entire world of ancient animal life that had completely died out and no longer existed.
It was a major scientific breakthrough, and it ultimately led to Charles Darwin and his ground-breaking ideas. Ironically, Cuvier reconciled the reality of extinction with his own views by assuming that there had been a whole series of eras, with each being wiped out by some catastrophe and in turn replaced by a new suite of animals. “Life on earth.” he concluded, “has often been disturbed by terrible events.” Cuvier is today most remembered for his stubborn rejection of the idea of “evolution”, and his enormous contributions to science are largely forgotten.
Today, the original Mosasaurus skull is on display in the National Museum of Natural History in Paris, and a plaster-cast copy is in the Natural History Museum in Maastricht (where the informational signage indignantly declares that the original was stolen by the French). In December 2023, the government of the Netherlands formally requested that the Maastricht skeleton be returned, stating that it is an important part of the Dutch historical and scientific legacy, and that it had been illegally taken from the country by force without consent. Paris has not made any formal reply to this request, but it has made statements that, having been displayed in the national museum for over 200 years, it considers the fossils to be a part of the country’s national heritage, and they are protected under French law as a significant cultural and scientific artifact. And there the matter rests.
NOTE: As some of you already know, all of my diaries here are draft chapters for a number of books I am working on. So I welcome any corrections you may have, whether it's typos or places that are unclear or factual errors. I think of y'all as my pre-publication editors and proofreaders. ;)
