Blackford Hill

This guide to Blackford Hill in Edinburgh follows a day in 1840 when the Swiss geologist Louis Agassiz examined the scratched rock on this hillside and challenged how Scotland's landscape had always been explained. You'll hear how a newspaper editor documented the encounter, and what set Agassiz's reading of the marks apart from generations of local geologists. The guide also traces the andesite itself, a lava flow far older than the ice that later scored it.