Essex Field Club on Facebook

Video about the Club Essex Field Club video

Dichomeris marginella
find out more... Dichomeris marginella. Copyright: Stephen Rolls

Essex Field Club
Essex Field Club
registered charity
no 1113963
HLF Logo A-Z Page Index


Essex Field Club

When you shop at Amazon DonatesAmazon Donates

Visit Our Centre

EFC Centre at Wat Tyler Country ParkWe are closed due to the Covid-19 situation, but we are otherwise normally open to the public at our centre at Wat Tyler Country Park every Saturday, Sunday and bank holiday 11am-4pm, check. We are also normally open on Wednesdays 10am-4pm.

Geology Site Account

A-Z Geological Site Index

Pit north-west of Wanstead Park (site of), WANSTEAD, London Borough of Redbridge, TQ402881, Historical site only

show OS map    

Site category: Periglacial deposits and features

Temporary exposures in the 19th century revealing unusual geological features. Further excavations in the vicinity could yield further information.


Site description

In 1898 a 'remarkable section of contorted gravels' was exposed in a pit ‘about a furlong north-west of Wanstead Park’. The contorted gravel was overlain by a layer of undisturbed gravel which was recognised to be of more recent age. The pit is described in a paper by Martin Hinton published in the Essex Naturalist in 1900. Hinton said that the seams of sand and gravel were ‘so twisted up as to resemble loose knots’.

Hinton attributed the disturbances to the grounding of river ice but they are now known to have had a different origin. Contortions such as these are called ‘involutions’ and geologists know how they were formed because the same processes are going on in the Arctic today. In southern Britain, during the coldest periods of the Ice Age, the ground was permanently frozen (permafrost) with only the top metre or so thawing during each brief summer and freezing again in the autumn. Constant freezing and thawing over thousands of years created remarkable contortions in layers of gravel close to the surface.

The geological map shows this area to be situated on the high terrace, known as the Boyn Hill/Orsett Heath Terrace. The gravel of this terrace is thought to have been originally laid down by the river about 400,000 years ago following the diversion of the Thames by the Anglian Ice Sheet (Marine Isotope Stages12¬10). The lower gravel in this pit is therefore of this great age and was contorted during a subsequent glacial stage. The undisturbed layer of gravel above was laid down thereafter.

The exact location of the pit is not known but the most likely candidate is the pit that formerly existed on land now occupied by Addison Road and Dangan Road (approx. TQ 402 881) and clearly shown on the 1868 six inch Ordnance Survey map.


if you have an image please upload it

Reference: Hinton 1900a, Hinton 1900b, Butcher 1915.

Geology Site Map
A-Z Geological Site Index