Great Quarry (SSSI) and Old Town Railway Cutting (SSSI)
Location and Access Information
Grid Reference: SU 151834, SU 151836 and SU 153836
These disused quarries and railway cutting are located close to the centre of Swindon in north-west Wiltshire. All of the exposures are accessible on foot and have recently been cleared to provide better views of the rocks. Car parking is available in the streets adjacent to the sites.
View the site map on Nature on the Map
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Geological Interest
These quarries (originally quarried for building stone) and railway cuttings expose limestones and sandstones of late Jurassic age (approximately 150 million years old). The lower part of the succession contains a variety of fossils, including bivalves and ammonites, providing evidence of a shallow and warm tropical sea in the area. Later, the sea retreated, leaving a complex of freshwater and saline lagoons and channels. These conditions are reflected in the different fossils that these rocks contain. The reappearance of marine fossils at intervals within the succession indicates occasional re-invasions by the sea. This group of sites provides important evidence of the changing environmental conditions in this part of Britain at the close of the Jurassic Period.
