Ipswichian Interglacial

The principal Ipswichian sites lie in east and southeast England. This Interglacial started about 135,000BP and lasted until about 73,000BP.

A closed canopy of boreal forest dominated by birch and pine developed at the start of the Ipswichian Interglacial. Later oak and elm occur, the latter becoming dominant as Hazel and Montpelier Maple (Acer monospessulanum) appear. The latter now has a southern and central European distribution, and although it can now grow in Britain does not set viable seed. The presence of Water Chestnut (Trapa natans) also suggests that the climatic optimum of the Interglacial was perhaps 2 to 3° C warmer than the Flandrian or current postglacial periods, and probably more continental. Water Fern (Salvinia natans) is known only in the Ipswichian and an undated pre-Cromerian warm stage.

The later part of the Ipswichian is characterised by a rise to what appears to be dominance in the forest of another warmth loving species, the Hornbeam. At the same time oak and Hazel decline in importance, while there is a reciprocal rise in pine and the forests become more open. The Hornbeam declines into the post temperate phase of the Ipswichian and deciduous forest gives way to an open boreal forest of pine and birch. The spruce, which characterises this period on the continent, is absent from British Ipswichian sites.

Late Ipswichian Forest

In the Thames valley many sites have been attributed to the Ipswichian. They seem to occur beneath two separate terraces which have different mammal assemblages. The higher terrace (Middle or Taplow Terrace at Ilford and Aveley) has Woolly Mammoth (Mammuthus primigenius), Merck’s Rhinoceros (Stephanorhinus kirchbergensis), Narrow-nosed Rhinoceros (Stephanorhinus hemitoechus), Verticornis Deer (Premegaceros verticornis), Northern Vole (Microtus oeconomus) and a small variety of Horse (probably Equus ferus). The lower terrace (Upper Floodplain Terrace, e.g. Trafalgar Square) has Hippopotamus (Hippopotamus amphibius), Straight-tusked Elephant (Palaeoloxodon antiquus), Merck’s Rhinoceros, Common Shrew (Sorex araneus), Mountain Hare (Lepus timidus), Fox (Vulpes vulpes), Wild Boar (Sus scrofa), Brown Bear (Ursus arctos), Fallow Deer (Dama dama dama), Badger (Meles meles), Red Deer (Cervus elaphus), Aurochs, Steppe Bison (Bison priscus), Lion (Panthera leo), Water Vole (Arvicola terrestris cantiana), Field Vole (Microtus agrestis), Wood Mouse (Apodemus sylvaticus), White Toothed Shrew (Crocidura suaveolens) and Spotted Hyaena (Crocuta crocuta). The Severn valley would have had similar faunal assemblages.

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Hippopotamus upper jaw and lower tusk, and lower canine

Woolly Mammoth and Straight-tusked Elephant actually occur together in some Ipswichian deposits, possibly because the former could live in open vegetation under any climate and the latter preferred temperate forest.

A large part of the later Middle Palaeolithic period coincides with the Ipswichian Interglacial. Tools of the earlier Middle Palaeolithic seem to consist of handaxes, flakes, Levallois flakes and blades, side-scrapers, points, cores and pebble/chopping tools. In the later Middle Palaeolithic tool designs changed with the introduction of the small Micoquian handaxes and knives and the classic triangular handaxes/knives which are commonly found in England and elsewhere. The term 'Micoquian' comes from a cave in southwestern France where these tools were first identified.