Geology Site Account

Site name: Mashbury Hall Puddingstone

Grid reference: TL 651118

Brief description of site:

On private land at Mashbury Hall farmyard is a boulder of Hertfordshire puddingstone (110cm x 90cm x 60cm in size). Either side of the puddingstone are boulders of Carboniferous limestone and a very course-grained gritstone.

E.A.Rudge stated that this boulder was originally found on the side of the valley about one kilometre south of Mashbury Hall (Cooper 1994). The limestone and gritstone boulders were no doubt also recovered from nearby farmland and probably originate from Derbyshire, brought to Essex by the Anglian ice sheet.

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Hertfordshire puddingstone

Hertfordshire Puddingstone was formed around 55 million years ago when the climate of Britain was hot and a layer of pebbles 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 in Hertfordshire, hence the name, and were probably carried to Essex by the River Thames when it flowed north of its present course. However, the distribution and abundance of Hertfordshire puddingstone in parts of Essex suggests that some occurrences may have a local Essex source.

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.

The Mashbury Hall Puddingstone (photo: Mike Howgate)