Ipswichian Stage
[Ge]
A group of deposits representing a geostratigraphic stage within the Pleistocene series of the British Quaternary system system, represented by a series of lacustrine muds, river terraces, and estuarine and marine sediments overlying Wolstonian Stage sands and gravels, and sealed by Devensian Stage deposits containing material indicating cold conditions. Traditionally, Ipswichian deposits are taken to represent a single warm phase, the last interglacial, dating to the period 150 000 years ago down to 115 000 years ago. There may in fact be considerable variation within the period. Archaeologically, Mousterian artefacts of the Middle Palaeolithic are found in Ipswichian deposits. Equivalent to the Riss-Würm in the Alpine sequence, the Sangamon in North America, and the Eemian in northern Europe.
