Pebbles are usually found only on the beach, in the liminal space between land and sea. But what happens when pebbles extend inland and create a ridge brushing against the sky? Landscape in the Longue Durée is a 4,000 year history of pebbles. It is based on the results of a four-year archaeological research project of the east Devon Pebblebed heathlands, a fascinating and geologically unique l…