J.M. Bowker contributed a paper on 'Fossils from the farm Wiepe, northern Transvaal' to the Proceedings of the Geological Society of South Africa (1907, Vol. 10, p. 34-). His finds, which came from the Bushveld Sandstone Formation, were later described by R. Broom* in 'On the remains of a theropodous dinosaur from the northern Transvaal' (Transactions of the Geological Society of South Africa, 1912). Bowker was a member of the Geological Society of South Africa in 1906, and is identified as J. Mitford Bowker of Johannesburg. In later years he is listed as a member of the society living in Francistown, Botswana (1914) and then in Salisbury (now Harare, Zimbabwe, 1919).
There were at least three adult persons named J. Mitford Bowker living in South Africa at the time. The most likely candidate is John Mitford Bowker (1864-1929), fifth child of Thomas Holden Bowker*. With his brother Miles McGowan Bowker* he moved to Johannesburg in the late eighteen-nineties, where they dealt in mining properties. After the Anglo-Boer War the two farmed at Potchefstroom for a while before Miles moved to Zimbabwe. John must have followed him, for he died in Harare in 1929.
Another possibility is John Mitford Bowker (1849-1927), third child of Octavius B. Bowker*. John served in the Frontier Wars in the Eastern Cape, then became a farmer in the eastern Free State, and lived in the Transvaal from before the discovery of gold on the Witwatersrand (1886). In his old age he lived on the farm "Linkwoods" in the Zoutpansberg. He has been described as a good-hearted person who readily assisted others.
A less likely candidate is John Mitford Bowker (1839-1924), second child of William Monkhouse Bowker (1803-1876). He married his niece, Sarah Elizabeth (Libby) Bowker in 1856.