Fitton, William Henry (1780–1861), geologist, was born in January 1780in Dublin, son of Nicholas Fitton, lawyer, and was distantly related to the Fitton family of Gawsworth, Cheshire; nothing is known of his mother. He was educated at TCD, where he was senior scholar (1798) and graduated BA (1799). He spent some more years at TCD, during which he undertook geological study trips to Wales and Cornwall, and also determined barometrically the heights of the principal mountains in Ireland. In 1808 he moved to Edinburgh, where he studied medicine; he eventually gained the degree of MD from two universities, Edinburgh (1810) and Cambridge (1816), and was elected a fellow of the Royal College of Physicians on 23 December 1816.
He settled in London for some years, where he joined several scientific societies including the Astronomical, Geographical, and Linnean. While there he co-authored with the Rev. Walter Stephens (d. 1808) an important memoir on the geology of Dublin that appeared in two editions, 1811 and 1812. In the latter year he moved to Northampton, where he practised medicine for eight years till he married Mary James, a lady of considerable means; they subsequently had five sons and three daughters. Because of his wife's wealth he was able to abandon his profession and devote himself to scientific and leisurely pursuits. He was admitted FRS 9 November 1815, and in the following year a fellow of the Geological Society of London.
Fitton soon became a leading light and administrator of the Geological Society and served on the council (1822–30, 1831–46), as secretary (1822–4), and president (1827–9). During his term as president he instituted the society's Proceedings and the annual presidential address. The Royal Society and other London scientific societies were soon to adopt a similar scheme. Fitton's stratigraphical work on the Jurassic and Cretaceous rocks of southern England remains by far his most important. In two papers (published 1824, 1836) he described and distinguished the Upper and Lower Greensand and the Gault clay which underlie the Cretaceous chalk, and compared the British sections with those across the Channel in France. He was also an important reporter of contemporary geological writings, and wrote lengthy reviews of the contemporary geological writings of William Smith, William Buckland, Roderick Murchison, and Charles Lyell, which were published in the Edinburgh Review (1818–41). It was Fitton's review of Smith's map and books that allowed their significance to become generally known to the geological community of that time. In all, he published twenty-one geological papers. He was awarded the Wollaston medal by the Geological Society of London in 1852. It has been suggested that he was the inventor of the thaumatrope, a once popular parlour amusement device; however, the credit for this animation toy may belong to John Ayrton Paris. Fitton was well known as an outgoing individual who was friendly but could be peppery and short-tempered. He died 13 May 1861 at his residence at Sussex Gardens, London. A photographic portrait is reproduced in Woodward (1908). Some fossil collections are at the Natural History Museum, London.