Jurassic

Jurassic is one of the geological periods through which the South Coast’s exposed rocks tell a story of deep time. In the account of the Jurassic Coast, the period sits between the Triassic and the Cretaceous, giving the landscape a timescale far beyond the human histories also encountered along the route. The book does not assign the period exact dates; instead, it shows how its place in the sequence becomes tangible in rock, fossils, and the changing ground beneath the walkers’ feet.

A period written into the coast

The Jurassic Coast begins at Old Harry Rocks and extends for ninety-five miles along the south coast to Orcombe Point near Exmouth. Its eroding cliffs expose more than 185 million years of geological history across the Triassic, Jurassic, and Cretaceous periods. The coast is thus not presented as a single, timeless formation: its rocks preserve successive chapters, made visible as the path follows the shoreline.

That geological record includes fossilized plants and animals, from tree ferns and insects to molluscs and mammals. Some remains preserve even the last meal of the creature. The stones hold life in a moment arrested across immense spans of time, turning the coast into both landscape and archive. The walkers encounter the Jurassic not through an abstract definition, but through the material evidence that erosion has brought into view.

Reading the boundary on foot

At Lulworth Cove, the walkers pick up a leaflet and try to work out whether their route is moving from the Cretaceous into the Jurassic. They eventually give up and buy chocolate bars and hot water instead. The small episode brings geological time down to the scale of a day’s walking: periods that are clear in a guide’s account become difficult to distinguish while following a path through a complex coastal landscape.

The cliffs at the cove are described as white rock threaded with black, and the beach is scattered with smooth black and white pebbles. The setting is crowded with visitors, but its beauty is also evidence of geological change. Later, the walkers pass the vast arch of Durdle Door as dusk settles over the white cliffs. The route’s landmarks offer dramatic forms to look at, while the rock sequence behind them asks to be read across a timescale no individual journey can encompass.

Fossils and other measures of time

At Lulworth, a ledge offers a view of fossilized growths in the rocks below: broad, rounded forms with central depressions. The guide Paddy Dillon identifies them not as the remains of a mythical creature but as conifers that grew 135 million years ago, preserved in their original soil. The walkers’ comparison between that explanation and the formations’ strange appearance makes the distant past immediate without making it familiar. The fossils are traces of living things, but also evidence of a world whose duration exceeds ordinary human memory.

The narrative places this deep time beside much more recent geological change. Leaving the sea near Lyme Regis, the walkers enter the Undercliff, formed when eight million tonnes of soil slipped toward the sea on Christmas Eve 1839. The resulting chasm has since become a dense, naturalized landscape. That landslip is not identified as part of the Jurassic period; its function in the account is to set a dramatic, historically datable transformation beside the far older fossil record. Together, the scenes show how the coast holds different kinds of time in close proximity.

Significance in the journey

For Ray and Moth, geological history is encountered through movement: cliffs, fossils, slopes, and the uncertainty of reading a leaflet along the route. The Jurassic belongs to a sequence that cannot be grasped all at once, just as the walkers’ passage reveals the coast one stretch at a time. The path links successive views while the exposed rock supplies a record older than the human stories unfolding above it.

This contrast gives the Jurassic Coast more than scenic significance. Its fossils and strata make change visible, preserving traces of life across immense spans while erosion continues to expose and alter the record. Against that scale, a day’s walk is brief; yet walking provides the means by which the geological past becomes perceptible, through particular stones, cliffs, and discoveries along the way.