BGS GeoSure data is provided as a series of layered themes. Depending on the scale of data chosen, up to five main themes are available.
Example dataset: The Lea Valley, London.
The area is mainly underlain by silty clay of the Eocene London Clay Formation. Outcrops of the silty Claygate Member of the London Clay, capped by the sandy Bagshot Formation, occur near Loughton and Chigwell. To the north and north-west, the London Clay has been eroded to expose the clay, silt and sand of the Lambeth Group and, below these, outcrops of the Cretaceous Lewes Nodular Chalk Formation.