First Person: ‘I used the world’s oldest fossil find as a doorstop’

I was mustering sheep on our farm in South Australia when I found the fossil. It’s pretty wild and desolate out here, about 300 miles north of Adelaide. The land is semi-arid outback and in the summer temperatures often hit 50C. Even during a good year, we only average 6in of rainfall annually.

My family has been farming sheep and cattle in this area for five generations, stretching back to the 1850s. We manage about 200,000 acres and although that might sound large, vegetation is so sparse that each cow needs 120 acres of grazing to survive. The largest farm in Australia is further up the state – it covers six million acres.

I became interested in rocks when I was a child. I grew up on a farm that my brother now runs just north of here, in the Flinders Ranges. It’s a pretty spectacular area, attracting tens of thousands of tourists, walkers and fossil hunters a year.

About 500 million years ago this entire area was a shallow sea that stretched for hundreds of miles inland. As the waters receded, the land that was left filled with sand and mud, which was perfect for compacting and creating fossils.

I didn’t learn much about fossils at school but I read plenty of books. Early marine fossils are called Ediacara biota. They were the ancestors of sea snails, sponges and crustaceans that we find in the sea today. As the water disappeared, their fossil imprints were left preserved on layers of sandstone around our farmland.

That day in 1999 I was rounding up sheep on a remote area of the farm where fossils had been discovered before. I had a small collection on the veranda and palaeontologists would sometimes come by to see them. I was looking for small ripples in the rock formations, where I had found them before.

I saw a large slab on the ground with a big fossil on it. Then I noticed there was also a smaller fossil, about 6cm long, which looked like a tadpole with a large head. It looked different to what I had seen before, so I came back later with a truck and took it home. For many years I used it as a doorstop and nobody took much notice. Then about four years later a palaeontologist took some photographs of the fossil and researched it at the South Australian Museum, in Adelaide.

The experts there thought it was a creature that crawled around on the bottom of the ocean floor. It had a stiffening rod along its back, which is what differentiated it from multicellular blobs and what would ultimately become man. They said it dated back 560 million years, pre-dating the previous oldest fossil find, in China, by some 30 million years.

Suddenly we had palaeontologists from all over the world arriving at the farm. There were TV crews and journalists flying in by helicopter, all for a piece of rock that had been sitting on my veranda. David Attenborough turned up – he spent a couple of days with us filming a piece for his First Life series. Even he was pretty amazed, so I started to realise how important my find was.

There was so much interest that I decided it would be best if the fossil went on display. The museum in Adelaide was keen to have it, so I agreed to let them take it away. I’m happy it’s in safe hands and I visit it when I’m in the city.

I still drive down to where I found the rock, just to see if I can spot another one like it. There have been all kinds of digs and surveys in the area since, so I think I was just lucky that day. It could have stayed undiscovered for a further 560 million years, or been eroded by the weather.

The whole experience has made me think more about life on Earth and how we got here. I think it’s incredible that a little mark on a rock was there 560 million years ago. Compared to that, man has only just arrived on the planet.

Main photograph: Molly Harris