# Dictionary of National Biography, 1885-1900/Oldham, Thomas

​OLDHAM, THOMAS (1816–1878), geologist, born at Dublin on 4 May 1816, was eldest son of Thomas Oldham and his wife, Margaret Bagot. He was educated at a private school, and began residence at Trinity College, Dublin, before completing his sixteenth year. In the spring of 1836 he proceeded B.A., and then went to Edinburgh, where he studied engineering, and attended the geological lectures of Professor Jamieson, the two becoming intimate friends. After a stay of about two years in Scotland, he returned to Dublin.
The work of Oldham's life may be divided into two periods—the one spent in Ireland, the other in India. Appointed in 1839 on the geological department of the ordnance surveyor of the former country, he was engaged especially in surveying the counties of Kerry and Tyrone, the report of this work being published in 1843. At Trinity College he was appointed assistant professor of engineering in 1844, and professor of geology in 1845. He held official positions at the Dublin Geological Society, becoming its president in 1846. In that year, too, he took the degree of M.A., and was also appointed local director for Ireland of the Geological Survey of the United Kingdom.
In addition to official work, Oldham communicated twelve papers on the geology of Ireland to the Dublin Geological Society, or to the British Association, and in 1849 had the good fortune to discover, in the Cambrian, or slightly older, rocks of Bray Head, co. Wicklow, the singular fossils or organic marks which have been named after him, Oldhamia.
In November 1850 Oldham was appointed by the directors of the East India Company superintendent of the Geological Survey of India, and reached that country early in the following year. Though his staff of assistants was small—about twelve in number—yet, largely owing to his industry and powers of organisation, rapid progress was made with the work, and in about ten years an area in Bengal and Central India twice as large as Great Britain had been surveyed and recorded. During this work coalfields had received ​especial attention, and, as the result, an elaborate report ‘On the Coal Resources of India’ was presented to the secretary of state for that country. Sixteen memoirs on separate subjects were also published.
Oldham's official labours left him little time for independent authorship, but he communicated one paper (on upper cretaceous rocks in Eastern Bengal) to the ‘Quarterly Journal of the Geological Society of London,’ and was joint author of another; he also wrote, in conjunction with Professor John Morris [q. v.], a memoir on the fossil flora of the Rajmahal series. Altogether his separate papers number about thirty-four. But the best memorial of his administration and scientific ability will be found in the publications of the Indian Geological Survey. These form four sets: (1) ‘Annual Reports,’ commenced in 1858; (2) ‘Records,’ commenced in 1868; (3) ‘Memoirs’ (on separate districts), commenced in 1859; (4) ‘Palæontologica Indica,’ that is, descriptions and figures of the organic remains obtained during the survey. Oldham's last work in India was to complete the transfer of the library and collection of the Geological Survey from its former quarters to the Imperial Museum of Calcutta. A quarter of a century of arduous labour had so much weakened his health that in 1876 he retired from the survey, and, on his return to England, resided at Rugby, where he died 17 July 1878. He married in 1850 the daughter of William Dixon, esq., of Liverpool, by whom he left a family of five sons and one daughter.
Oldham was elected a member of the Royal Irish Academy in 1842, F.G.S. in 1843, and F.R.S. in 1848; he became a member of the Royal Asiatic Society of Bengal in 1857, and was four times its president. In 1874 he received the honorary degree of LL.D. from Dublin, and in 1875 the royal medal from the Royal Society, and a gold medal from the Emperor of Austria, after the Vienna exhibition. He was also a member of many societies, British and foreign.
[Obituary notices in Quart. Journ. Geol. Soc. London, 1879, Proc. p. 46, and Geol. Mag. 1878, p. 382, supplemented by information from R. D. Oldham, esq.]
T. G. B.