Beach combing on the coast that time forgot

From an eco retreat hidden in the wilds of Patagonia, Mike Unwin explores a shoreline of petrified forests, penguin colonies and fascinating fossils

What is it about a particular seashell – one among countless millions on the beach – that entices you to pick it up? I ponder this question as I slip another little calcified trophy into my pocket. An hour into our stroll and this beach combing is becoming addictive.

The next find proves more challenging. At first glance, the bleached shard of bone seems an easy addition to the collection. But on closer inspection it turns out to be the protruding tip of a massive vertebra buried deep in the sand: part of a long-dead southern right whale. Thankfully, younger hands – the teenage children of a Belgian family also staying at Bahia Bustamante – get stuck into the excavation, allowing us adults a chance to learn a little more about this beach and its treasures from our host Matias Soriano.

We spread out our finds on the sand as Matias draws on his gourd of hot matte tea – Argentina’s national infusion – through a silver bombilla pipe. “This is a fossil oyster,” he says, picking out one ridged disk of stone. “It’s 20 million years old.” We sift though the pile – sponge, crab shell, penguin skull – as he explains how people have been foraging on these beaches for centuries. “The Tehuelches once lived here,” he tells us. “They knew just how to make a living from the sea – that is, before we Europeans arrived and pushed them into reservations.”

Our young companions have now excavated the bone and for good measure added a giant rib. Selfies duly taken, it’s time to get going again. Leaving our trophies on the windy beach, we troop inland into the dunes. In sheltered depressions between thorny thickets, heaps of shells reveal a former Tehuelches campsite. Matias picks out a flat-bladed stone tool from one ancient midden and explains how these indigenous hunter-gatherers survived on seafood when winter made hunting inland impossible.

I try to imagine a family hunkering down 400 years ago in this very spot, braced against a winter gale as they chiselled open the day’s haul. For a moment I feel an uncomfortable sense of intruding somewhere secret. As if on cue, a Magellanic owl takes flight

South American sea lions grouped around a large ‘beachmaster’ male, above