Molluscs of the Eemian Interglacial in Poland

Shells of subfossil snails and bivalves commonly noted in deposits of the Eemian Interglacial were used by several authors as more or less important stratigraphic indicators. In Poland, they have been noted in 35 sections, 20 of which are described as basic ones. Molluscan assemblages found at these sites include 60 species of freshwater molluscs and 58 species of land snails, the former being dominant. Climatic tolerance of particular species is the main attribute deciding on their stratigraphic values. Cold-tolerant snails are typical of the preceding Late Glacial and some of them occur also in early phases of the interglacial, while species connected with moderate climate and warm-demanding ones characterise the middle part of the Eemian Interglacial. The freshwater snail Belgrandia marginata is typical of the climatic optimum of this interglacial. Particular species of molluscs were related to regional pollen assemblage zones of the Eemian Interglacial in Poland.