Geology Site Account

Site name: Spains Hall Sarsen Stone, Finchingfield

Grid reference: TL 6788 3408

Brief description of site:

A large sarsen boulder (1.9 metres x 1.9 metres x 0.3 metres in size), completely obscured by vegetation, lies adjacent to a flint wall surrounding cottages in the grounds of Spainshall Farm.

----------------------------------------

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 probably originated on the chalk downland of south Cambridgeshire and after retreat of the ice they became concentrated in river valleys.