5
THE QUATERNARY OF THE LOWER REACHES OF THE THAMES
Report of an important field meeting organised by the Quaternary Research Association
Thanks to the work of David Bridgland and others considerably more is known about the
ice age (the Quaternary era) in Essex than only a few years ago. We are now beginning to
unravel the complex sequence of cold and warm stages that are represented in Essex by
gravels, sands and clays that have been laid down over the last 600,000 years. In
particular, valuable work has recently been done on the evolution of the River Thames as
it migrated south through Essex to its present position. It was against this background
that the Quaternary Research Association (QRA) organised an important field meeting
from 13th to 16th October last year to sites in Essex and north Kent which was also open
to non members. Despite some frustrating but often amusing mishaps the excursions
were a success and they provided the participants with a unique opportunity to visit some
of the most important ice age sites in Britain.
Day one started with a visit to a railway cutting at Hornchurch, nationally famous for
providing evidence of the most southerly extent of the great Anglian ice sheet some
500,000 years ago. Railtrack charges the QRA several hundred pounds for permission to
visit (and the loan of fluorescent jackets) and insisted that only a small number could
view the section at any one time. As over 50 people had turned up the visit took up most
of the morning. The afternoon was spent south of the river at sites in the Thames terraces
including Swanscombe, internationally famous for the discovery of the fragmentary skull
of an early stone age woman, some 400,000 years old.
Day two started at Purfleet, where a remarkably complete section through a Thames
terrace could be seen in two adjacent quarries. The party then proceeded to Aveley where
permission had been obtained to excavate a new section through the fossiliferous Aveley
deposits, famous for the discovery of two elephant skeletons in the mid-1960s.
Unfortunately it didn't quite turn out that way as the land owner, apparently suspicious
that it was something to do with the channel tunnel rail link, refused to allow access. The
JCB excavator that had, at some expense, been hired for the occasion (complete with
operator) was therefore of no use whatsoever. Undaunted, the party moved on to the next
site, Lion Pit, West Thurrock, where a Palaeolithic (old stone age) 'working floor' could
be seen. Then across Essex to Great Wakering which has excellent exposures of loess
(brickearth) in Star Lane pit. With the prior permission of the MoD the party then moved
on to Foulness where fine 'chenier' shell ridges could be observed in the gathering
darkness. Some members arrived after dark and missed them altogether but consolation
was available in a Foulness pub with an enjoyable few hours of talks and slides.
Day three began at South Woodham Ferrers where a Mesolithic (middle stone age) land
surface is visible on the river bank. The rest of the day was spent at East Mersea with its
remarkable channel deposits at Cudmore Grove Country Park. It is difficult to imagine a
time when hippopotamus were wallowing in a river that flowed through here some
125,000 years ago, but the proof was in an interglacial bone bed that has been described
as one of the richest in England. Also at Cudmore Grove are sediments laid down by the
River Thames when it flowed through here some 400,000 years ago. In these have been
found the bones of monkey, beaver and bear. As an example of the organisation that went
into this event we arrived at the hippopotamus site to find a 9 foot deep trench already cut
into the beach, at the bottom of which was the Natural History Museum's curator of fossil
mammals ready to explain the stratigraphy. This scene attracted much curiosity from
nearby holidaymakers at this popular spot.