The youngest part of the London Clay, known as the Claygate Beds or Claygate Member forms a transition between the clay and the sandier Bagshot Beds above. This is shown separately on many geological maps, and often caps hills. It is up to 15 metres (49 ft) thick at Claygate, Surrey.[1] It is now believed to be diachronous, with the formation at Claygate for example being the same age as the end of the fourth cycle of deposition further east.[3]