Shock cliff discovery reveals key stage in Earth’s development

The world’s oldest fossil forest – dating back 390 million years – has been discovered in the UK, shedding light on a key stage in Earth’s development.

The fossilised trees are palm-like in appearance but would have had thin trunks with hollow centres, researchers say.

The remains were discovered in the Hangman Sandstone Formation near Minehead, close to a Butlin’s holiday camp.

This fossil forest is around four million years older than the previous record holder – found in a sandstone quarry in the town of Cairo in New York State.

Researchers from the Universities of Cambridge and Cardiff said these ancient plants – called Calamophyton – would have been “prototypes” of modern-day trees.

They would also have been quite short, somewhere between two and four metres tall, with branches covered in hundreds of twig-like structures instead of leaves.

Professor Neil Davies, from Cambridge’s Department of Earth Sciences, said: “This was a pretty weird forest – not like any forest you would see today.

“There wasn’t any undergrowth to speak of and grass hadn’t yet appeared, but there were lots of twigs dropped by these densely packed trees, which had a big effect on the landscape.”

The forest belongs to a geological time period known as the Devonian Period, between 419 million and 358 million years ago.

It was a time when marine animals started to diversify and seed-bearing plants first appeared.

Prof Davies said: “The Devonian period fundamentally changed life on Earth.

“It also changed how water and land interacted with each other, since trees and other plants helped stabilise sediment through their root systems, but little is known about the very earliest forests.”

Alongside fossilised plants, the team also identified plant debris, fossilised tree logs and traces of roots – all preserved within the sandstone.

Dr Christopher Berry, from Cardiff’s School of Earth and Environmental Sciences, said: “When I first saw pictures of the tree trunks, I immediately knew what they were, based on 30 years of studying this type of tree worldwide.

“It was amazing to see them so near to home.

“But the most revealing insight comes from seeing, for the first time, these trees in the positions where they grew.”

Prof Davies added: “The evidence contained in these fossils preserves a key stage in Earth’s development, when rivers started to operate in a fundamentally different way than they had before, becoming the great erosive force they are today.

“People sometimes think that British rocks have been looked at enough, but this shows that revisiting them can yield important new discoveries.”

Scientists had previously assumed this stretch of coast in south-west England did not contain significant plant fossils.

But the researchers now say their findings, published in the Journal of the Geological Society, show how ancient trees helped stabilise riverbanks and coastlines hundreds of millions of years ago.