Geology Site Account

Site name: Woodcock Lodge Boundary Stone

Grid reference: TL 6126 0100

Brief description of site:

Sarsen stone lying partly hidden by a hedge, on the roadside verge next to a gate adjacent to Woodcock Lodge on Blackmore Road.

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Summary of the geological interest:

This sarsen stone lies partly hidden by a hedge, on the roadside verge next to a gate adjacent to Woodcock Lodge on Blackmore Road. It stands approximately 70cm out of the ground and probably extends into the ground by at least 20 cm as it is firmly fixed into the soil.

It is significantly located at the old boundary between Fryerning Parish and a detached part of Ingatestone Parish. It was probably a glacial erratic boulder ploughed up from a local field or more likely excavated from the local gravel pits around Fryerning and brought to mark the boundary. Many such stones were used as boundary markers.

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Scientific interest and site importance

Sarsens are an extremely hard 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. The formation of silcretes (which includes sarsens) has been the subject of recent scientific debate. Research has compared the conditions under which sarsens were formed with the present day climate in the Kalahari Desert and parts of Australia. The stones are tough and very resistant to erosion and have survived the rigours of the Ice Age. They probably originated on the chalk downland of south Cambridgeshire and were brought south by the ice sheet.

Sarsens are uncommon in this part of Essex: they are usually encountered in the north and west of the county.