Geology Site Account

London Borough of Waltham Forest, WALTHAMSTOW, Excavations for the Victoria Line

London Clay, which underlies much of London, is a good tunnelling medium. It is easy to excavate, keeps out groundwater and is stiff enough to be self supporting. During the late 1960s, when the Victoria Line was under construction between Brixton and Walthamstow, great quantities of London Clay had to be disposed of and London Transport Underground dumped a large amount of it from the Walthamstow section in a London Clay pit serving Woodside Brickworks near Croydon.

Members of the Tertiary Research Group visited the Woodside Brickworks pit during a visit to the Croydon area in October 1971 and inspected the mound of clay from Essex which was then estimated to be 120 feet thick; enough clay, it was said, to keep the brick kilns working at 200 tons per week for 20 years. The clay was found to contain rounded and flattened septarian nodules described as ‘cheeses’ and some lighter coloured clays from the Woolwich Beds. Some fossils were collected which included brachiopod shells and stems of crinoids (sea lilies) but otherwise it appears to have provided little evidence of life on the floor of the London Clay Sea some 50 million years ago.

Reference: Cooper 1975

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