Geology Site Account

Site name: Audley End Sarsen Stone. Opposite Audley End House entrance, Audley End Road, Saffron Walden.

Grid reference: TL 5234 3800

Brief description of site:

A fine sarsen stone lies on the grass by the road opposite the Lion Gate entrance to Audley End. Stones such as this boulder are known as glacial erratics and were carried to Essex by the Anglian Ice Sheet, which covered almost the whole of Britain during the coldest period of the Ice Age, some 450,000 years ago.

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Summary of the geological interest

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.

Sarsen stones link geology, archaeology and social history. The history of this boulder is not known. It was probably found on nearby Audley Estate farmland in the nineteenth century and placed here by the fourth Lord Braybrooke who had a large natural history collection, much of which can still be seen in the house. It was perhaps used as a mounting block.

Sarsen stones are quite common in Essex, although this one is of large size. It is in a conspicuous position on the roadside near to the main entrance of Audley End and thus has great potential for geological education. The stone is about 110 centimeters long, 90 centimeters wide and 50 centimeters thick.

Audley End Sarsen Stone. Photo: G.Lucy