The London Clay
The mud under London holds a tropical flora — palms, mangroves and nipa fruit from a Thames estuary.
- When
- —
- Duration
- 7 million years
- Known to
- ± 1 million years
- Era
- Eocene, Cenozoic
The London Clay was deposited in a warm shallow sea in the earliest Eocene, and the fossil fruits and seeds washed into it record the vegetation on shore: palms, magnolias, cinnamon, and the nipa palm that today grows only in Southeast Asian mangroves. Over 350 plant species have been identified. The formation also yields early birds, turtles and sharks, and — because every deep foundation and tube tunnel in London cuts through it — it is among the most thoroughly sampled rock units in the world.