and re-position them. Fossils Fossils of the echinoid Micraster from the Chalk Group have been studied for their continuous morphogical variation throughout the record. Mosasaur remains referred to "Mosasaurus" gracillis from the Turonian aged Chalk Group deposits actually are more closely allied to the Russellosaurina. A single partial maxillar tooth from Cenomanian aged Chalk Group described as "Iguanodon hilli" belongs to a non-Hadrosaurid Hadrosauroid. See also Chalk stream Downland Geology of Great Britain Southern England Chalk Formation References Further reading Geological groups of the United Kingdom Geologic formations of England Upper Cretaceous Series of Europe Cretaceous England Chalk Petroleum geology Lithostratigraphy of England