British pioneers of the geology of Gibraltar, Part 1: the artilleryman Thomas James (ca 1720-1782); infantryman Ninian Imrie of Denmuir (ca 1752-1820); and ex-militiaman James Smith of Jordanhill (1782-1867)

The rocky peninsula of Gibraltar juts south from Spain at the western entrance to the Mediterranean Sea. Long famous as a landmark, it was ceded to Great Britain by the Treaty of Utrecht in 1713, and progressively developed as a naval and military base. Thomas James, a Royal Artillery officer stationed on Gibraltar from 1749 to 1755, was the first member of the British garrison to publish geological observations on the Rock, within a book of 1771 completed in New York. His military career culminated after active service against revolutionary Americans, finally in the rank of major-general, but with no further known contributions to geology. The Scotsman Ninian Imrie of Denmuir, an officer of the First Regiment of Foot (The Royal Scots), served on Gibraltar within the period 1784 to 1793, and was the first to publish an account specifically on its geology, in the Transactions of the Royal Society of Edinburgh in 1798. A career soldier, he achieved the rank of lieutenant-colonel before retiring to Scotland, and to amateur geological studies influenced by active membership of Edinburgh's Wernerian Natural History Society. James Smith of Jordanhill, near Glasgow, served in Great Britain in the Renfrewshire Militia during the Napoleonic Wars but, benefiting from a family fortune, later spent much time as a yachtsman and scholar of wide interests and influence. His studies on Gibraltar, published by the Geological Society of London in 1846, were the first to attempt a tectonic interpretation of the Rock's geological history, and to record local evidence for Quaternary sea level change.