 It is also to be found beneath the scarp of the Berkshire Downs, in the Vale of White Horse, in Oxfordshire, England, and on the Isle of Wight where it is known as Blue Slipper.Gault underlies the chalk beneath the London Basin, generally overlying eroded rocks of Jurassic and Devonian age; lower gault is present only below the outer parts of the basin and is absent under central London.The Gault Formation represents a marine transgression following erosion of the Lower Greensand.