Barton Beds (now the
Barton Group) is the name given to a series of grey and brown
clays, with layers of
sand, of Upper
Eocene age (around 40 million years old), which are found in the
Hampshire Basin of southern England. They are particularly well exposed in the
cliffs at
Barton-on-Sea, which is the world type locality for the Barton Beds, and lends its name to the
Bartonian age of the Eocene
epoch. The clay is abundant in
fossils, especially
molluscs.