a1 Laboratoire de Paléontologie des Vertébrés, Université Paris VI, Case 106, 4, place Jussieu, 75252 Paris Cedex 05, France
Two genera of armoured dinosaurs (Ankylosauria) are present in the Lower Cretaceous Wealden Beds of England. Polacanthus Owencan be distinguished from Hylaeosaurus Mantell on the basis of significant differences in the pectoral girdle, hindlimb and dermal armour. A comprehensive review of the dinosaurs from the Wealden Series of England and contemporary basins of western Europe adds further evidence of a biologicalseparation between Lower Wealden (Hastings Beds, containing Hylaeosaurusarmatus) and Upper Wealden faunas (Wealden Group of the Isle of Wight-containing Polacanthus foxii-and nearly equivalent units in Belgium, France, Germany and Spain).
(Received August 06 1992)
(Accepted June 15 1993)