They belong to the upper Eocene formation of the London and Hampshire basins,[1] in England and derive their name from Bagshot Heath in Surrey.

The Lower Bagshot Beds may be observed at Brentwood, Billericay and High Beach in Essex; outliers, capping hills of London clay, occur at Hampstead, Highgate and Harrow.

In Surrey, considerable tracts of London clay are covered by heath-bearing Lower Bagshot Beds, as at Weybridge, Aldershot, Woking etc.

Here it consists of unfossiliferous sands (white, yellow, brown, crimson and every intermediate shade) and clays with layers of lignite and ferruginous sandstone.

[2] The leaf-bearing clays of Alum Bay and Bournemouth are well known and have yielded a large and interesting series of plant remains, including Eucalyptus, Caesalpinia, Populus, Platanus, Sequoia, Aralia, Polypodium, Osmunda, Nipadites and many others.