​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 Hamstead 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.