BEMBRIDGE BEDS  , in

geology, strata forming part of the fluvio-marine series of deposits of Oligocene age, in the Isle of Wight and Hampshire, England . They lie between the Ham-stead beds above and the Osborne beds below . The Bembridge marls, freshwater, estuarine and marine clays and marls (70-120 ft.) rest upon the Bembridge limestone, a freshwater pool deposit (15—25 ft.), with large land snails (Amphidromus and Helices), freshwater snails (Planorbis, Limnaea), and the fruits of Chara . The marls contain, besides the freshwater Limnaea and Unio, such forms as Meretrix, Ostrea and Melanopsis . A thin calcareous sandy layer in this division has yielded the remains of many insects and fossil leaves . See " Geology of the Isle of Wight," Mem . Geol . Survey, 2nd ed . 1889 .