Geologist and MP. He was the only surviving child of George Bellas (d. 1784) and his wife Sarah. In 1795 he adopted the surname of his maternal grandfather, the wealthy apothecary Thomas Greenough, on inheriting the latter’s fortune. A Dissenter, he completed his studies at the University of Göttingen in the late 1790s and befriended Samuel Taylor Coleridge. He returned to England in 1801 and was elected a member of the Royal Society in 1807. In the same year he was a founder-member of the club that became the Royal Geological Society. He supported the Society for the Diffusion of Useful Knowledge, was a founder-member of the British Association for the Advancement of Science, and a proprietor of the company that established University College, London. Between 1807 and 1812 he sat as an MP for the pocket borough of Gatton. In 1818 he lent Southey books on the Guarani language and was thanked for so doing in the final volume of the History of Brazil (1810–1819).