In 1822, while Mary Ann Mantell was accompanying her husband, Dr. Gideon Mantell, to Surry as he was visiting a patient, she discovered large tooth-shaped fossils on the side of the road. She presented these fossils to her husband.(3) Due to his excitement of her findings he launched and excavation of the Tilgate Forest, which resulted in the discovery of the herbivorous reptile, the Iguanodon. (3)(4)

Mary Ann Mantell aided her husband by illustrating many of the fossils in his scientific work called "Illustrations of the Geology of Sussex" published in 1827, in which he describes the Iguanodon, thusly named due to its likeness to the modern day Iguana. (3)(4)

....their personal lives suffered and the pair became increasingly distant causing their marriage to end in divorce. They had three children together, including prominent New Zealand scientist and politician Walter Mantell.