Anglian Glaciation
The Anglian glaciation occurred between approximately 475,000 and 425,000 years ago. This was the last time that major ice sheets reached East Anglia. There were two subsequent periods of glaciation in the British Isles but the ice sheets did not reach as far south as East Anglia on these occasions. This glaciation deposited a thick layer of glacial till or boulder clay across central Suffolk, radically altering the landscape and the drainage pattern.
