Sollas, William Johnson (1849–1936), geologist, was born 30 May 1849 in Birmingham, eldest son of William Henry Sollas, shipowner, and Emma Sollas (née Wheatley). He was educated in London at the Royal College of Chemistry and the Royal School of Mines, following which he was awarded a scholarship to the University of Cambridge. He was successively professor of geology and zoology at Bristol (1879–83), professor of geology and mineralogy at TCD (1881–97), and professor of geology and mineralogy at Oxford (1897–1936).
Sollas's early research was on fossil sponges, about which he became the acknowledged world expert and wrote the account for the Encyclopaedia Britannica (9th ed., 1887). While in Ireland he carried out research on trace fossils from the Cambrian rocks of Bray and Howth, on aspects of the Leinster granite, and on the origins of marbles; mapped and accounted for the eskers of the midlands of Ireland; and with Robert Lloyd Praeger (qv) produced a fine paper on the glacial deposits of the Dublin district. He was also an accomplished petrologist, who worked on a part-time basis for the geological survey of Ireland, and demonstrated the siliceous composition of flint by petrological methods. In 1897 he led an expedition to Funifuti atoll, off Australia, in an unsuccessful attempt to drill through its centre. He wished to determine if Charles Darwin was correct in his contention that atolls and barrier reefs were formed by the subsidence of a volcanic island, around which the coral grew. At Oxford Sollas turned his attention to anthropological studies and the age of the earth. Towards the end of his life he was suspected (falsely) of perpetrating the Piltdown hoax of 1912.
Sollas was elected FRS (1889); was president of section C (geology) of the British Association for the Advancement of Science (1900); and served as president of the Geological Society of London 1908–10. From that society he received the Wollaston Fund (1878), the Bigsby medal (1893), and the Wollaston medal (1907), and he was also awarded the Royal Medal of the Royal Society in 1914. He died at Oxford 20 October 1936.
He married first (1874) Helen Coryn (d. 1911) of Redruth, and secondly (1914) Amabel Nevill Mosley (d. 1928). He had two daughters, Igerna and Hertha, by his first wife, both of whom entered Newnham College, Cambridge. Igerna later assisted her father in an important study of a fossil lungfish from the Devonian of Scotland, in which they reconstructed the three-dimensional shape of the fossil through taking successive sections. Hertha was responsible for translating into English the influential geological work Das Antlitz der Erde (The face of the earth) by the Austrian geologist Eduard Suess.