GLA 46: Rainham Submerged Forest, Potential RIGS

GLA 46: Rainham Submerged Forest, Potential RIGS
London Borough of Havering, TQ 516 795
Ownership: Port of London Authority. Open access to the path and permission not required to visit the foreshore.

Part of a submerged forest, about 6,000 years old, is exposed on the Thames foreshore at Rainham Marsh. The forest, consisting of fallen tree trunks and roots, is of Neolithic age, a time when sea level was much lower1. Following the end of glacial conditions some 10,000 years ago, alluvium (silts and clays with seams of sand and gravel) was laid down by the River Thames on its floodplain. Trees colonised the mud flats when there were minor temporary falls in sea level and died when sea level rose. The site has educational importance in the interpretation of sea level changes since the end of glacial conditions some 10,000 years ago, and how this relates to our current concerns about global warming. A written record of this site was made in 1712 by Reverend William Dereham, Vicar of Upminster2. There are other submerged forests along the Thames (e.g. at Purfleet nearby and on the other side of the river at Erith, GLA 39) some of which were studied as early as 1665 but this is the best place within Greater London to view it on the north bank. Within the nearby RSPB site, during drainage maintenance, logs from the forest bed are found, possibly older than those occurring on the foreshore – one is on permanent display on the northern side of the RSPB site – unfortunately the RSPB charge to enter the site.


The sea wall footpath (Havering Riverside Path, also on the London Loop3) passes adjacent to the site. Rainham Railway Station is about 2 miles distant ( (Section 24)). The submerged forest can only be seen at low tide and care should be taken if going onto the foreshore. A falling tide is essential.


1 Bates, M.R and Barham, A.J 1995. Holocene alluvial stratigraphic architecture and archaeology in the lower Thames area, in Bridgland D, Allen, P and Haggart, B A (eds):The Quaternary of the lower reaches of the Thames, Field guide. Quaternary Research Association, Durham, pp 85-98.

2 Dereham, W. 1712. Observations concerning the subterraneous trees in Dagenham, and other marshes bordering upon the River Thames, in the County of Essex. Philosophical Transactions of the Royal Society. Vol. 27 pp.478-484.

Neolithic submerged forest on north bank of the Thames
Source: London’s foundations, page 210 (Diana Clements, July 2011)


Site Map OS Topography © Crown Copyright
Source: London’s foundations, page 208

gla46 map


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