In the 18th century, new scientific equipment allowed explorers to survey land and sea with greater accuracy than ever before. Some of George Vancouver's maps, in fact, are still in use today. An explorer and avid hunter, Palliser headed the "Palliser Expedition" which, from 1857 to 1861, explored the plains north of the 49th parallel and the passes through the Rockies. The expedition delineated a stretch of semi-arid land named "Palliser's Triangle", and the surrounding, "fertile belt" which was found suitable for stock raising and agriculture. Artist Frederick Hagan of Newmarket, Ontario painted these four images, third in the series of Exploration stamps. Using a palette of vivid colours, he depicts the lands carted by four 18th century explorers. His imaginative backgrounds detail charts, map-making tools and the Discovery, the ship Vancouver sailed on his voyage around the world.