Geology Site Account

Site name: Greenbank House Sarsen Stones

Grid reference: TL 981 321

Brief description of site:

Four sarsen stones are situated by the entrance to Greenbank House in Boxted Church Road near the junction with Holly Lane. Each is about 90 x 60 x 40 cm in size and they can be clearly seen from the roadside. The garden of the house contains over 20 sarsens, each one brought here by the owner from farmland in the nearby Stour Valley. Greenbank House is a private residence.

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Details

Sarsens are extremely hard boulders of sandstone formed around 55 million years ago when the climate of Britain was hot and a layer of sand beneath the surface of the ground became cemented with quartz. They are thus very resistant to erosion and have survived the rigours of the Ice Age. They originated on the chalk downland north and west of Essex and were carried here by rivers and glaciers. After retreat of the ice they became concentrated in river valleys.

The formation of silcretes (which includes sarsens and puddingstones) has been the subject of recent scientific debate. Research has compared the conditions under which sarsens and puddingstones may have been formed with the present day climate in the Kalahari Desert and parts of Australia.