Gideon Mantell - Geological Research

Geological Research

Inspired by Mary Anning's sensational discovery of a fossilised animal resembling a huge crocodile (later identified as an ichthyosaur) at Lyme Regis in Dorset, Mantell became passionately interested in the study of the fossilised animals and plants found in his area. The fossils he had collected from the region, near The Weald in Sussex, were from the chalk downlands covering the county. The chalk is part of the Upper Cretaceous System and the fossils it contains are marine in origin. But by 1819, Mantell had begun acquiring fossils from a quarry, at Whitemans Green, near Cuckfield. These included the remains of terrestrial and freshwater ecosystems, at a time when all the known fossil remains from Cretaceous England, hitherto, were marine in origin. He named the new strata the Strata of Tilgate Forest, after an historical wooded area and it was later shown to belong to the Lower Cretaceous.

By 1820, he had started to find very large bones at Cuckfield, even larger than those discovered by William Buckland, at Stonesfield in Oxfordshire. Then, in 1822, shortly before finishing his first book (The Fossils of South Downs), his wife found several large teeth (although some historians contend that they were in fact discovered by himself), the origin of which he could not identify. In 1821 Mantell planned his next book on the geology of Sussex. It was an immediate success with two hundred subscribers including a letter from king George IV at Carlton House Palace which read "His majesty is pleased to command that his name should be placed at the head of the subscription list for four copies."

How the king heard of Mantell is unknown, but Mantell's response is. Galvanised and encouraged, Mantell showed the teeth to other scientists but they were dismissed as belonging to a fish or mammal and from a more recent rock layer than the other Tilgate Forest fossils. The eminent French anatomist, Georges Cuvier, identified the teeth as those of a rhinoceros.

Although according to Charles Lyell, Cuvier made this statement after a late party and apparently had some doubts when reconsidering the matter when he awoke, fresh in the morning. "The next morning he told me that he was confident that it was something quite different." Strangely, this change of opinion did not make it back to Britain where Mantell was mocked for his error. Mantell was still convinced that the teeth had come from the Mesozoic strata and finally recognized that they resembled those of the iguana, but were twenty times larger. He surmised that the owner of the remains must have been at least 60 feet (18 metres) in length.