Temporary exposures of the Eocene London Clay Formation at Highgate, north London: rediscovery of a fossiliferous horizon ‘lost’ since the nineteenth century

Highgate, north London, was historically an important area for collectors of well-preserved macrofossils, particularly benthic molluscs, of the London Clay Formation. However, exposures have not been generally available since the nineteenth century. Auger holes and excavations made recently in the base of the cutting on the former branch railway line from Finsbury Park to Highgate have shown relatively unweathered, fossiliferous London Clay Formation to occur within 1 m of the surface. This is the lowest unit of division E. A comprehensive faunal list is presented for the basal clays, which are considered to represent a muddy marine shelf palaeoenvironment during the deepest phase of the London Clay sea.