Think of Kent with its white cliffs, chalk downs, and dull-coloured clays in this connection!
"Afoot in England"
W.H. Hudson
Selection, in fact, may be quite successfully made through the process of exclusion, and by eliminating all soils of a very light and sandy nature, or clays so tenacious that the surface bakes and cracks while still too wet within 3 or 4 inches of the surface to operate with farm tools.
"Cacao Culture in the Philippines"
William S. Lyon
There is clays, for instance.
"The Other Fellow"
F. Hopkinson Smith