Wealden Group

The Wealden Group lies stratigraphically on top of the Purbeck Group, which spans the Jurassic-Cretaceous boundary. Within the Wessex Basin, the Wealden Group consists of two formations: the Wessex Formation and overlying Vectis Formation. In the Weald Basin, the Wealden Group consists of four formations: the Ashdown Formation, the Wadhurst Clay Formation, the Tunbridge Wells Sand Formation and the Weald Clay Formation. The lower three formations are sometimes collectively referred to as the Hastings Beds. In Oxfordshire, Buckinghamshire and Wiltshire, the Wealden Group is only found as an outlier on top of hills and only consists of a single formation, the Whitchurch Sand Formation. In Yorkshire, the equivalently aged Speeton Clay Formation, a marine unit, is present. On top of the Wealden Group is the Lower Greensand Group. The difference between these two groups has been formed by a major eustatic (global) transgression of the sea. The Greensand (Aptian/Albian in age) consists of marine deposits. The sequence in the Weald Basin has also been described as a supergroup, containing the Weald Clay Group and Hastings Group. ==Palaeontology==

The Wealden Group forms outcrops covering a large part of south and south-eastern England including the Isle of Wight. It takes its name from the Weald region of Kent, Sussex, Surrey and Hampshire. It has yielded many fossils, including dinosaurs like Iguanodon and Hypsilophodon. Apart from fossils, it shows many other signs of being deposited in a continental environment, such as mudcracks and -in some rare cases- dinosaur footprints. Taxa included in the table below have an uncertain provenance and cannot be placed into one of the constituent formations, thus they are placed here. Pterosaurs Dinosaurs == Wealden elsewhere in Europe ==

The term "Wealden" and "Wealden facies" has been applied to other Lower Cretaceous sequences in Europe, including the "German Wealden", comprising the Berriasian aged Bückeberg Formation of the Lower Saxony Basin and in Belgium, where "Wealden facies" has been used as a term to refer to the Barremian-Aptian aged sequences of the Mons Basin, including the Sainte-Barbe Clays Formation where large numbers of Iguanodon were found in the 19th century. == References ==