Lieutenant-General Charles Alexander McMahon FRS FGS (23 March 1830 – 21 February 1904) was an Anglo-Irish soldier, geologist, and administrator in British India.
[1] Born at Highgate, McMahon was the son of Captain Alexander McMahon (born 1791), an officer of the East India Company, originally of Kilrea, County Londonderry,[1] by his wife Aim, a daughter of Major Patrick Mansell, a British army officer.
[3] He fought at Saintfield and Ballynahinch and fled to France, where he served in Napoleon’s Irish Legion and died fighting on the French side at Waterloo.
In 1879, while on leave in England, with the rank of lieutenant-colonel, he enrolled as a student at the Royal School of Mines.
Settling in London, he took up petrology, publishing papers which took the total number of his contributions to geology to nearly fifty.