Geology along The Strawberry Line

The Strawberry Line is not just a former railway route; it crosses a geological record spanning more than 300 million years, from the ancient rocks of the Mendips to the modern sediments of the Severn Estuary.

• Shepton Mallet / Mendips: The route begins among Carboniferous Limestone, formed around 359–327 million years ago in a warm tropical sea. Fossils include corals, brachiopods and crinoids. The rocks were later dramatically folded during the Variscan mountain-building period.

• Wells: The route passes beneath Pen Hill's Devonian sandstone before returning to limestone. Wells' famous springs occur because groundwater flowing through the limestone encounters impermeable clay and emerges at the surface.

• Cheddar and Axbridge: The Strawberry Line enters classic karst limestone country, associated with caves, fissures, pinnacles and sinkholes. Cheddar Gorge is a major example of this landscape. There is also evidence of a major geological time gap where younger Jurassic limestone lies on much older, tilted Carboniferous rock.

• Somerset Levels: North of the Mendips, the geology changes to younger Triassic mudstones and conglomerates, followed by Jurassic Blue Lias limestone. Some conglomerates contain distinctive quartz-lined nodules and geodes.

• Yatton: The route crosses the North Somerset Levels, largely formed from relatively recent peat and estuarine sediments deposited by rivers and tidal flooding. Cadbury Hill rises above this flat landscape as an isolated limestone outlier.

• Clevedon: The journey ends on the Severn Estuary, where Carboniferous Limestone hills and softer coastal deposits are being shaped by the exceptionally powerful tides of the Bristol Channel.