Tyrrell, Joseph Burr (tĭrˈəl) [key], 1858–1957, Canadian explorer and geologist, b. Ontario. In 1881 he joined the Canadian Geological Survey as an explorer and in 1883 accompanied G. M. Dawson on his expedition to the Canadian Rockies. He made other explorations in W and N Canada, but his best-known feat was his crossing (1893) of the barren grounds from Lake Athabaska to Chesterfield Inlet; his total journey, largely by canoe, covered some 3,200 mi (5,150 km). He compiled Documents Relating to the Early History of Hudson Bay (1931, repr. 1968). Tyrrell's brother, James Williams Tyrrell, 1863–1945, accompanied him on the expedition across the barren grounds and wrote an account of it in Across the Sub-Arctics of Canada (1897).