Geology Site Account

For the 'Aveley Elephants' see Sandy Lane Pit, Aveley

Site name: Aveley Clay Pits (London Clay)

Grid reference: TQ 556805

Description of site:

Extensive pits in the London Clay famous for fossils during their working life. These are now historical sites only as all but one of the pits has now been infilled. The only unrestored pit is at Bretts Farm (Aveley Lake) (TQ 555 822). This steep-sided clay pit is now a private fishing lake. Any new excavations should be reported and recorded.

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History of the Aveley Clay Pits

Until they ceased operation in 1976, the extensive clay pits in the Aveley area exposed a total of almost 50 metres thickness of lower and middle London Clay (Greensmith et al. 1973 and King 1981). The pits, which were operated by the Tunnel Cement Company, turned the clay into a slurry in large tanks on site and pumped it to West Thurrock to make cement. The largest pits were situated south of Sandy Lane (TQ 556 805) and north of Sandy Lane (TQ 553 807) and were known as No. 1 and No. 2 pits respectively (Ice Age deposits channelled into the London Clay at No.2 pit produced the famous Aveley elephants “ see separate site record). The two pits were linked by a tunnel underneath Sandy Lane. The pits produced thousands of fossils, which were used to obtain a picture of life on the floor of the muddy, subtropical sea that covered Essex during the Eocene period, about 50 million years ago. W.S. McKerrow, in his classic book The Ecology of Fossils (McKerrow 1978), based his reconstruction of an Eocene marine mud community on the London Clay fossils of Aveley.

During their working life the pits received visits from several geological societies including the Geologists Association (Blezard 1966) and the Tertiary Research Group (Kirby 1974). Kirbys 1974 report contained a review of the pits and their fossils and reported on research carried out which even extended to measuring the alignment of logs of fossil wood and drawing conclusions about the prevailing current on the sea floor. The fossils, several species of which were new to science, included, molluscs, corals, sea lilies, turtle bones, shark teeth, skulls of fish, complete shells of nautilus and magnificent specimens of crabs and lobsters. There were also numerous plant remains, from fruits, seeds and twigs to large logs, all of which must have floated long distances from the coastal rainforest out into the London Clay Sea.

Since the pits ceased working they remained disused for over ten years until landfill operations commenced in 1987. The process of re-excavating the pits to make them suitable for landfill brought many new fossils to light, most of them to amateur geologist Bob Williams who worked tirelessly on the exposures from 1991 until 1999 (Williams 2001). Landfill operations are complete at the Sandy Lane clay pits but further north the older pit at Bretts Farm (Aveley Lake) (TQ 555 822) has not been infilled. This steep-sided clay pit is now a private fishing lake but it is also a surviving example of an important local industry that yielded some of the best fossils of any London Clay site in London or Essex.

A 13 centimetre (5 inch) long fossilised lobster Hoploparia gammaroides from the London Clay at Aveley. Collected by Bob Williams in the mid 1990s. Photo © G. Lucy