James Guest was born in India in 1917 and came to school in England - first in London and afterwards in Yorkshire. On leaving school he joined the RAF, spending 10 distinguished years in its service. At the end of the War, Guest became an undergraduate at Sheffield University, graduating in 1948 with a BSc (First Class Honours) in Geology and Physics.
Guest began his career with the Colonial Geological Survey in 1949 carrying out primary geological mapping in Tanganyika (now Tanzania). During his posting there he developed his interest in economic minerals and saw his discoveries of copper, limestone, magnesite and meerschaum taken up by exploration and mining companies. Much of his scientific energy at this time was occupied in the exploration of the East African rift volcanoes, Mt. Kilimanjaro, Mt. Meru, and Oldonyo L’Engai. At the last, he was able to observe an eruption, collecting specimens of the very unusual sodium carbonate-rich lava ‘natro-carbonatite’, during a five day bivouac at the summit.
This pioneering work was developed as a research project and resulted in the award of a PhD from Sheffield University (1952). A career move in 1956 saw Guest and his family transferred to Fiji as Senior Geologist, with promotion to Chief Geologist in 1958. Though still mainly involved in geological mapping, Guest worked on various mineral deposits and developed an interest in the geology of the sea floor, becoming skilled in aqualung diving. His final posting with the Colonial Survey was in Kenya, where he was Chief Geologist, and subsequently, (in 1962) Commissioner of Mines and Geology.
Guest entered a new phase of his career in 1963, with an appointment in the Oceanographic Research Unit of the Anglo-American Corporation in Namibia, building on his experience of the economic and marine branches of his chosen science. Returning to the UK in 1967, he obtained an appointment as Lecturer in Applied Geology at Chelsea College, University of London, eventually becoming Director of Field Studies and supervising courses in a number of branches of geology. Throughout his working life, James Guest was remembered as a kindly and courteous colleague, and as an enthusiastic and supportive teacher.
Guest retired to Devon with his wife Barbara in 1979, living first in Moretonhampstead and then in Topsham, near Exeter. He continued his interest in geology, largely through the medium of the Ussher Society, in which he took an active interest, acting as Auditor for a number of years. He died in hospital after a short illness on 23 February 2001.
R C Scrivener and B J Williams