Mollusca from the Insect Limestone (Bembridge Marls Member: Bouldnor Formation: Solent Group), Palaeogene, Isle of Wight, southern England

摘要

Molluscs from the Insect Limestone of the Bembridge Marls Member are described. The gastropods Lymnaea (Galba) longiscata (Brongniart 1810), Planorbarius discus (Edwards 1852), Gyraulus similis Férussac, 1814, Hippeutis headonensis Jodot, 1942, Viviparus lentus (Solander 1766) and Viviparus angulosus (J. Sowerby 1817) indicate freshwater alkaline conditions. The cerithioid gastropod Tarebia acuta (J. Sowerby 1822) probably represent more brackish conditions. Polymesoda (Pseudocyrena) obovata (J. Sowerby 1817) is the only bivalve present. All were potentially washed into the depocentre. Despite a wide outcrop of the Insect Limestone on the Isle of Wight’s northwest and northeast coasts, there are no records of molluscs other than from the Gurnard/Thorness Bay area on the northwest coast of the island.