London Clay

London Clay, major division of Eocene rocks in the London Basin of England (the Eocene Epoch lasted from 57.8 to 36.6 million years ago); it immediately underlies much of the city of London. The London Clay overlies the Reading Beds, underlies the Bagshot Sands, and is included in the Ypresian Stage, the lowermost division of Eocene rocks and time. In the London Basin the London Clay is as much as 200 metres (600 feet) thick...