His work in this capacity saw Haast conducting numerous expeditions throughout Canterbury and Westland, making geological discoveries and topographical maps of the area. Late in 1861, he discovered a coal seam in Kowai and the following year searched for gold in the area around Aoraki/Mt Cook. He identified that the Mackenzie plains were once the bed of a major glacier and, as well as his geological observations, he collected numerous botanical specimens. He discovered and named many of the glaciers of the central South Island, including the Franz Joseph Glacier, in honour of the Emperor of Austria, Franz Joseph. He was the first person to study the bones of the extinct Haast's eagle.