[1] Born in Carsphairn, McKay reached New Zealand in 1863 where he spent a number of years prospecting for gold.
[2] A meeting with Julius von Haast saw a change of direction in which McKay, largely self-taught, undertook geological mapping and fossil collecting expeditions throughout the islands.
In 1867, he was based on an isolated farm in South Canterbury and in 1868 spent several weeks in Christchurch undertaking training with Edward Wheeler & Co. on wet-plate photography.
[2] He invented a telephoto lens and also techniques for taking images of geological collections and fossils.
[2] McKay's greatest achievement was to free New Zealand sciences from the strictures of European-based thinking, developing new theories, of worldwide importance, on block faulting in the evolution of mountain systems.