A Child’s Tooth, Burned Green Stone, and a Cave 7,300 Feet Up: The Mystery Rewriting Prehistoric Europe

Published: 25 Jul 2026

For decades, scientists assumed ancient people only passed briefly through the high mountains. Then researchers dug six square meters into a Pyrenean cave floor — and found evidence that someone kept coming back, for two thousand years.

Nobody expected the cave floor to hold much of anything.

Cova 338 sits more than 7,300 feet above sea level in the eastern Pyrenees, tucked into the Freser Valley — a punishing climb, thin air, brutal winters, no reason for anyone to linger. For as long as archaeologists have studied prehistoric Europe, the working assumption has been simple: early humans passed through places like this. They didn’t stay.

Then a team led by Prof. Carlos Tornero of the Catalan Institute of Human Paleoecology and Social Evolution began carefully peeling back the layers of dirt just inside the cave’s entrance. Six square meters. Four layers of buried time. And packed into two of those layers, something nobody was quite prepared for: 23 separate fire pits, some cutting into each other, filled with crushed fragments of a strange green mineral that had clearly been burned on purpose.

Then came the smaller find that changed the shape of the whole question. A single baby tooth. A tiny finger bone. Belonging, the researchers believe, to a child of about eleven.

Why was someone burning rock, again and again, across two thousand years, in a cave that shouldn’t have been worth the climb? And whose child ended up there?

Rewind and Setup

To understand why this discovery matters, it helps to understand what archaeologists thought they already knew.

High-mountain environments — anything above roughly 2,000 meters — have long been treated as the margins of prehistoric life. The reasoning was straightforward: thinner air, harsher winters, fewer resources, and none of the fertile lowland conditions that let early farming communities settle down. Mountain caves like Cova 338 were assumed to be waypoints at best — somewhere a hunting party might shelter for a night, not somewhere a community would return to, deliberately, generation after generation.

Cova 338 itself isn’t a dramatic-looking site. It’s a modest cave mouth in a remote stretch of the Freser Valley in Catalonia, part of the eastern Pyrenees mountain chain that separates Spain from France. Nothing about its position — steep, high, exposed — suggested it would overturn a decades-old assumption about how prehistoric people used mountain landscapes.

That’s precisely what makes the site’s excavation, led by Tornero’s team alongside co-author Dr. Julia Montes-Landa of the University of Granada, so significant. Their findings, published in the journal Frontiers in Environmental Archaeology, don’t just add one more data point to the map of ancient Europe. They challenge a basic assumption about where prehistoric people were willing — and able — to build a meaningful, repeated presence.

The team excavated a modest six-square-meter area near the cave’s mouth and identified four distinct layers of human activity, each representing a different slice of time. The most recent layer was thin and sparse, holding only scattered artifacts from more recent historical periods — a sign the cave saw little use in later centuries. The oldest and deepest layer contained nothing but scraps of charcoal, radiocarbon-dated to roughly 6,000 years ago — a faint, ambiguous trace of very early human presence.

It was the two layers in between that changed everything.

The Inciting Event

In the second and third layers, the researchers uncovered 23 hearths — fire pits — packed with large quantities of crushed and burned fragments of green mineral. Preliminary analysis suggests the material resembles malachite, a copper-rich ore that can be processed into usable metal when heated correctly.

If that identification holds up, it would mean Cova 338 functioned as a strikingly early high-altitude mining or ore-processing camp — a place where people were repeatedly hauling raw material up a mountainside, building fires, and working copper ore at a height and remoteness nobody expected for this kind of activity.

That was the question that launched the real investigation: were these hearths evidence of a genuine, repeated industrial activity — early metalworking — happening at an altitude and scale nobody had documented before? Or was there a simpler, more mundane explanation for a cave full of burned green rock?

The Investigation

The first clue came from the mineral fragments themselves. Many of them showed clear signs of having been thermally altered — deliberately heated, not merely caught in an accidental blaze.

“Many of these fragments are thermally altered, while other materials in the cave are not, which clearly suggests that fire played an important role in their processing and that there was a deliberate intention behind it,” Montes-Landa explained. “In other words, they weren’t burned by accident.”

That ruled out one simple explanation — a random fire that happened to scorch some rocks lying around. It pointed instead toward purposeful, repeated activity. But that answer immediately raised a bigger question: repeated by whom, and how often?

The hearths themselves held the next clue. Many of the 23 fire pits overlapped one another, cut into each other’s edges — clear evidence that the same patch of cave floor had been used again and again over time. And yet each hearth remained distinct enough to be individually identified, which told the researchers something important: these weren’t the remains of one long, continuous stay. They were separate visits, spaced out — likely by years, possibly by generations — but returning, deliberately, to the exact same spot.

Radiocarbon dating sharpened the picture further. The hearth in the second layer dated to roughly 3,000 years ago. The hearths in the layer below it spanned an even wider window — somewhere between 5,500 and 4,000 years ago. Put together, the evidence pointed to a site that mattered to people across roughly two millennia, not two decades.

That raised the next question: if this was just a functional mining stop, why would anyone bother returning to the same remote, physically punishing location instead of finding ore somewhere more convenient? The answer started to come into focus when the team looked at what else had been left behind.

Alongside the burned mineral, researchers recovered two pieces of jewelry from the second layer: a pendant carved from a shell, and another made from a brown bear’s tooth. Both were traced to prehistoric contexts, likely around the second millennium BC.

“We recovered two pendants: one made from a shell and another from a brown bear tooth,” Tornero said. “They come from prehistoric contexts, most likely around the second millennium BC. The shell pendant is interesting because it has parallels in other sites in Catalonia, which suggests shared traditions or connections between different communities. The bear tooth pendant is much less common. That might point to something more specific or symbolic, possibly linked to the local environment.”

The shell pendant’s design connected Cova 338 to a wider web of communities across Catalonia — suggesting this wasn’t an isolated mountain outpost cut off from the rest of prehistoric society, but a site linked, culturally and materially, to people living far below. The bear-tooth pendant, rarer and more locally specific, hinted at something more personal — a symbol tied to the mountain environment itself, perhaps to the identity of whoever wore it.

Jewelry complicated the simple “mining camp” theory. People weren’t just showing up, burning ore, and leaving. They were bringing — or making — objects with personal and symbolic weight. That’s not typically what a purely functional, resource-extraction stop looks like.

And then, in the same layer as the hearths, the team found the human remains.

The Twist

A finger bone. A baby tooth. Both belonging, the researchers estimate, to at least one child around eleven years old.

Up to this point, the excavation had been building toward a fairly coherent story: an early, repeatedly visited high-altitude mining camp, its workers occasionally leaving behind personal ornaments. But the presence of a child’s remains — inside a working hearth layer, not an obviously separate burial context — reframed the entire site.

There currently isn’t enough evidence to determine how the child died, or even whether the finger bone and the tooth came from the same individual. That uncertainty matters, and the research team has been careful not to overstate what the bones can tell us. But their location — mixed into the same archaeological layer as the mining hearths and pendants — raises a real possibility the team is now taking seriously: Cova 338 might not have been purely a workspace. It might also have functioned, at least at some point, as a burial site.

That’s the twist buried in this excavation. A site initially framed around early copper processing — a story about labor, resources, and metallurgy — may also be a story about death, memory, and return. If deeper excavation confirms additional burials further into the cave, as the researchers suspect it might, Cova 338 stops being simply an industrial curiosity and becomes something closer to a place of enduring, generational significance — somewhere prehistoric communities returned to not just to work, but perhaps to remember.

It’s worth being precise here about what is confirmed and what remains an open question. Confirmed: the hearths exist, the mineral fragments show deliberate thermal alteration, the radiocarbon dates span roughly two thousand years, and the child’s remains were recovered from the third layer. Still unconfirmed: whether the green mineral is definitively malachite, whether the cave functioned as a formal burial site, and how — or when — the child died. The researchers have been explicit that these questions await further lab analysis and next season’s excavation.

The Climax

Put together, what the evidence currently supports is this: starting around 5,500 years ago, and continuing on and off for roughly two millennia, small groups of people made the difficult climb up to Cova 338, over 2,000 meters above sea level, again and again. They built fires. They deliberately heated and crushed a green mineral that closely resembles copper ore. They left behind jewelry that connected them to communities in the valleys below, while also carrying at least one symbol — the bear-tooth pendant — that may have been unique to this mountain environment. And at some point, in that same layer of activity, the remains of a child came to rest there too.

None of that fits the old assumption that prehistoric people treated high mountains as marginal, pass-through places. It suggests something closer to intentional, sustained, meaningful engagement with an extreme landscape — communities who knew this specific location, valued it enough to keep returning to across many human lifetimes, and who did more there than simply extract a resource and leave.

“For a long time, high-mountain environments were seen as marginal, places prehistoric communities passed through occasionally,” Tornero said. “But we found a really rich archaeological sequence, including multiple combustion structures and a very large number of green mineral fragments. We can’t say exactly how long people stayed each time, but the repeated use of the space and the density of remains suggest occupations that were short to medium in duration, but happening again and again over long periods of time.”

That is the central discovery: not a single dramatic event, but a pattern — a cave that mattered to people, deliberately and repeatedly, across roughly two thousand years of prehistory.

The Aftermath

The excavation at Cova 338 is not finished. The dig has not yet reached the full depth of the site, which means the complete sequence of human activity there — including whatever might lie beneath the layers already uncovered — remains undocumented. Researchers plan to resume fieldwork this summer.

Several questions are still actively being worked on. Laboratory teams at the University of Granada and the Autonomous University of Barcelona are running further tests to confirm whether the green mineral really is malachite, and if so, where it originally came from. That answer will determine whether Cova 338 represents genuine evidence of early copper mining and processing, or something related but distinct.

The fate of the child whose remains were found in the hearth layer also remains unresolved. Researchers don’t yet know the cause of death, whether the finger bone and tooth came from the same individual, or whether additional burials are waiting deeper in the cave — a possibility the team considers real enough to prioritize in future digging.

What’s already clear, though, is that a modest six-square-meter excavation at the mouth of a remote Pyrenean cave has produced evidence that runs against a long-standing assumption in archaeology: that prehistoric people avoided investing meaningfully in high-altitude environments. Cova 338 suggests otherwise — a place people kept returning to, for work, for symbolism, and possibly for their dead, across roughly two thousand years of human history.

The mountain didn’t give up its full story yet. But the tooth, the bones, and the burned green stone have already rewritten part of it.

This article is based on the peer-reviewed study published in Frontiers in Environmental Archaeology, and on interviews and material provided by Frontiers and reported by ScienceDaily. Details regarding the exact identity of the green mineral, the cause of the child’s death, and whether the site functioned as a formal burial ground remain unconfirmed and are the subject of ongoing research, expected to continue through further excavation this summer.