THOMAS, HUGH HAMSHAW

(b. Wrexham, Denbighshire, Wales, 29 May 1885; d. Cambridge, England, 30 June 1962)

paleobotany.

Born and brought up in Wales, Thomas spent all of his adult life in Cambridge, apart from service in the two world wars. He was the son of William Hamshaw Thomas and Elizabeth Lloyd. His father, a men’s outfitter, was active in the public service of his community. Hugh Hamshaw, the second son, was educated at a private school, Grove Park, until he won a scholarship to Downing College, Cambridge, in 1904. His early interest in fossils, which he collected in the local coalpits, continued at Cambridge, where he read for the natural sciences tripos and took part I but changed to history for part II, although continuing to keep up his interest in botany. He was particularly influenced by A. C. Seward, the professor of botany, and in 1908, the year he graduated, his first scientific paper was published in the Philosophical Transactions of the Royal Society.

Intended for the civil service, Thomas took the examination but rejected the post he was offered and remained in Cambridge. He supported himself by elementary tutoring while continuing his research, mainly with E. A. N. Arber of the Sedg-wick Museum of Geology. In 1909 he was appointed curator of the Botany School Museum, a post that he held until 1923; during this time he gradually shifted his teaching to botany. In 1911 he worked for a few months with Nathorst in the Stockholm Museum, and he appears to have also visited Russia about the same time. His election as a fellow of Downing College in 1914 gave him financial security.

Thomas spent most of World War I with the Royal Flying Corps in the Near East developing new techniques of mapping from aerial photographs, which were of considerable strategic importance. He continued his work in this field when he returned to Cambridge and kept in touch with research there. His work is still cited today. His interest in aerial photography also brought about his only work on ecology; he wrote on the flora of the Libyan desert and on the aerial survey of vegetation.

In 1923 Thomas was appointed to a university lectureship, and he married Edith Gertrude Torrance from Cape Town, who encouraged him to collect fossils in South Africa. They had one daughter and one son, who studied aircraft engineering and continued some of his father’s work.

Thomas spent World War II with the RAF in England, where he was in charge of a specialist unit on photographic interpretation for Intelligence.

Thomas’ scientific work was important because of the comprehensiveness of his collecting and fieldwork, his techniques of interpretation, and his detailed work on the systematics of fossil plant groups. Paleontology was mainly carried out in museums at that time, but Thomas collected extensively in England and in many areas abroad. Seward encouraged him to reexamine the Jurassic flora of Yorkshire, which resulted in Thomas’ series of papers published between 1911 and 1925.

Work with Nathorst and with Thore Gustaf Halle, whom he also met in Stockholm, showed him the importance of a detailed examination of impressions of the epidermis from fossil plants. He extended this approach to attempts to examine even the compressed internal structures, which was a feature of his most important paper on the Caytoniales in 1925. In this paper he examined the leaves, particularly the petioles, the ovaries, and the pollen organs of hundreds of specimens before concluding that the family, which he named, was closely related to the angiosperms, although not in the direct line of descent. Thomas’ paper on Triassic pteridosperms from South Africa, published in 1933, was also important because the pteridosperms were at one time a dominant group in the Southern hemisphere. The publication of this paper was followed by his election in 1934 as a fellow of the Royal Society.

Although Thomas had no formal training in geology, he did some work for the Geological Survey. His later publications on comparative morphology of plants were received with reservations by some of his colleagues. He also wrote on the history and philosophy of science.

BIBLIOGRAPHY

I. Original Works. The two major papers are “The Caytoniales, a New Group of Angiospermous Plants from the Jurassic Rocks of Yorkshire,’ in Philosophical Transactions of the Royal Society, 213B (1925), 299–363; and “On Some Pteridospermous Plants from the Mesozoic Rocks of South Africa,” ibid., 222 (1933), 193–265.

Thomas appears to have written no books, but there are several monographs listed by Thomas M. Harris, published by the British Museum (Natural History) and the Russian Geological Committee. His work for the Geological Survey is not listed by Harris and comprises “Refractory materials. . . .” in Geological Survey Special Reports on the Mineral Resources of Great Britain16 (1920): and “The Geology of the South Wales Coal field”, in Geological Survey Topographical Memoirs, 10–12 (1909–1916).

II. Secondary Literature. Most comprehensive is the obituary by Thomas M. Harris, in Biographical Memoirs of Fellows of Royal Society. 9 (1963). 287–299. which includes a bibliography of his major works.

Diana M. Simpkins