Haresfield Beacon earned its designation as a geological Site of Special Scientific Interest in 1985, and for good reason. The steep slopes of this promontory expose a sequence of Jurassic rocks that geologists consider a classic reference site of national importance. The Cotswold escarpment is essentially the broken edge of a great slab of limestone, tilted and uplifted over millions of years, and at Haresfield the erosion has cut deep enough to reveal the layered history of a shallow tropical sea that covered this part of England roughly 170 to 200 million years ago. The oolitic limestone that forms the bulk of the Cotswolds — the honey-coloured stone used in every village from Chipping Campden to Bath — was laid down as tiny spherical grains of calcium carbonate rolling on the seabed, accumulating layer upon layer. At Haresfield, different beds of limestone, clay and sandstone are exposed in the cliff faces, each recording changes in sea depth, current and climate over millions of years. The limestone grassland on the summit is itself a product of this geology: the thin, alkaline, free-draining soil supports a flora quite different from the clay vales below. Orchids, rock-rose and wild thyme thrive here precisely because the soil is poor — richer ground would be overwhelmed by coarser grasses. The view from the topograph looks out across the Severn Vale, but the real story lies in the 200-million-year journey from tropical seabed to Cotswold hilltop beneath your feet.
“At Haresfield, different beds of limestone, clay and sandstone are exposed in the cliff faces, each recording changes in sea depth, current and climate over millions of years.”
