Douglas S.S. Steuart, British mining engineer and author, was a Fellow of the Geological Society of London (FGS) and spent some time in South Africa around 1898-1899. In the latter year, but not earlier, he was listed as a member of the Geological Society of South Africa residing in Pretoria (though his name was spelt wrongly as D.S.S. Stewart). In 1898 he became a member of the Chemical and Metallurgical Society of South Africa. He was still listed as a member in 1905, after the Anglo-Boer War (1899-1902) and after the society had been renamed the Chemical, Metallurgical and Mining Society of South Africa, but his address was not known at this time.
A comprehensive paper by Steuart on "The mineral wealth of Zoutpansberg: the Murchison range gold-belt" was published in the Transactions of the (British) Institution of Mining Engineers (1899, Vol. 17, pp. 388-425). It was his first significant publication. Somewhat earlier geological accounts of this 140 km long, relatively narrow, east-north-east trending schist belt in the Low Veld of the north-eastern Transvaal had been published by A.R. Sawyer* (1892), C. Wilson-Moore* (1896), and A.F.J. Bordeaux* (1898). Gold had been discovered in the range in 1870.
Later Steuart wrote a booklet on The metalliferous deposits of Cornwall and Devon (London, 1913, 51p). No other scientific books by him are known. However, towards the end of his life he published two small works of fiction, The wolf-man's story (1947, 78p) and The warning vision (1949, 55p).