For three years, starting in 1878, he supervised the excavation of the famous, multiple Iguanodon find at Bernissart, Belgium. He devoted himself to their study as a scientific passion, initially concurrently with his engineering career.[2] In 1882 he became an assistant naturalist at the Royal Belgian Institute of Natural Sciences. Dollo was given membership in the Société des sciences de Lille and the Geological Society of London.