The South Dorset Ridgeway lies like a dinosaur’s tail parallel to the Jurassic Coast. I was walking along its spine which is crenelated with tumuli and the broken vertebrae of ancient earthworks. A male skylark was singing like a recording from u-tube and bumble bees seemed to be crashing into things. Tortoiseshell butterflies spread their wings on the chalky path, bonking beetles bonked on the sour-smelling cow parsley and poppies grew surreptitiously among the barley. Overhead, swifts were swimming in a watery sky which merged with the sea in the distance. I could see the curve of the earth all around. I imagined the ancient people plying their trade along this route, bringing granite quern stones from Cornwall and exotic goods from further afield. In those days the slopes of the Ridgway were densely wooded. Ambush must have been a fear for the lonely traveller. Suddenly a spaniel appeared, charging round the bend towards me – we both jumped, startled out of our separate reveries.