A brief history of the Earth on a walk around the Isle of Arran, Scotland

A six-day hike on Arran – a new Unesco Geopark – reveals tales of dinosaurs, tectonic plate collisions and lightning strikes from millions of years ago

Around 240m years ago, a 12-foot-long reptile called a chirotherium walked along a beach in what was then part of the supercontinent of Pangaea, and what is now the shoreline of Kildonan village, on the rugged, southern coast of the Isle of Arran. Natural dykes of black igneous rock – cooled magma – jut out into the ocean here. The houses on shore are backdropped by grassy cliffs.

We know that this giant proto-crocodile once roamed here because it left behind footprints – which can still be seen today. “This is older than the dinosaurs,” says Malcolm Wilkinson of Arran Geopark, as we crouch down next to the trace fossil. I place my hand in the massive print and attempt to imagine the world millions of years ago, when Scotland sat just north of the equator and the climate was tropical.