Geology Site Account

Site name: Ingatestone boulders

Grid reference: TQ 6511 9967

Brief description of site:

Erratic boulders on the roadside and in the churchyard in Ingatestone town centre

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Summary of the geological interest:

The site consists of three glacial erratic boulders (sarsen stones) at two locations in the town centre. Two of the sarsens can be seen at the junction of the High Street and Fryerning Lane (TQ 6511 9967), the largest one standing one metre (3'3") above ground. Another stone is situated a short distance away adjacent to the south door of St. Edmund and St. Mary Parish Church in the High Street (TQ 6511 9959). The latter stone stands 90 centimetres (3 feet) above the ground and the church guidebook states that it was originally buried beneath the north wall.

The stones were carried to this area 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. Local legend claims that these three stones were once part of a single large boulder but sarsens are extremely tough rocks and their appearance leaves no doubt that they were separate finds. They are probably glacial erratic boulders ploughed up from local fields or more likely excavated from the local gravel pits around Fryerning and brought to the town centre for practical or religious reasons.

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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. It is therefore unusual to find three large examples so close together. The sarsens of Ingatestone have been referred to in books and articles on the landscape and history of Essex (eg. Salter 1906 and Rudge 1964). The stones are water-worn and typical of sarsens elsewhere in Essex.

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Other information

The stones are of historic interest. They link geology, archaeology and social history. It is obvious that they have been moved by humans to their present position but when and why this was done is not known. The stone by the church door is reported to originally have been found beneath the north wall, which suggests that the church is built on a former pagan site. It has been suggested that these stones may have been responsible for the 'stone' in the name of the town.

The sarsen stones at the entrance to Fryerning Lane. Photo: G.Lucy