Born in Unley, Adelaide, Australia, the youngest child of John Thomas Edward Tilley, a civil engineer from London, and his wife South Australia-born wife, Catherine Jane Nicholas.
Educated at Adelaide High School, then studied Chemistry and Geology at the University of Adelaide, and the University of Sydney, graduating in 1915.
In 1916 he went to South Queensferry near Edinburgh, Scotland, to work as a chemist Department of Explosives Supply.
He returned to Australia in December 1918.
He won an Exhibition of 1851 scholarship to the University of Cambridge in 1919, where he studied petrology and completed his PhD in 1922.
From 1923 he worked for Cambridge University, first as demonstrator in petrology, and then lecturer in petrology in 1929.
In 1931 he was appointed as the first Professor of Mineralogy and Petrology.
Most of the remainder of his life was spent in England.
In 1938 he was elected a Fellow of the Royal Society of London and served as their Vice President 1949/50. He won the Society's Royal Medal in 1967.
1948-51 President of the Mineralogical Society of Great Britain.
1949-50 President of the Geological Society.
1957 Honorary Fellow of the Royal Society of Edinburgh.
He died at home in Cambridge on 24 January 1973.