Clay-with-Flints

In geology, clay-with-flints is the name given by William Whitaker in 1861 to a peculiar deposit of stiff red, brown, or yellow clay containing unworn whole flints as well as angular shattered fragments, also with a variable admixture of rounded flint, quartz, quartzite, and other pebbles.

Occurrence
The Formation is associated with deposits of the Chalk Group, subsequent Palaeogene and Neogene strata, and occasionally Upper Greensand. It occurs in sheets or patches of various sizes over a large area in the south of England, from Hertfordshire on the north to Sussex on the south, and from Kent on the east to Devon on the west. It almost always lies on the surface of the Upper Chalk, but in Dorset, it passes on to the Middle and Lower Chalk, and in Devon, it is found on the Chert-Beds of the Selbornian group.

Origin
The formation is now considered to be a combination of residual and cryoturbated strata, and to be of a variety of ages.