 In the Thames valley, in broad patches brickearth overlies fluvial terrace gravel; it has been reclassified on later maps as the "Langley Silt Complex".Brickearth is a superficial deposit of homogeneous loam or silt deposited during the Pleistocene geological period.Brickearth typically occurs in discontinuous spreads, across southern England and South Wales, south of a line from Pembroke in the west to Essex in the east in depths of up to a metre.