William Logan, geologist and first director of the Geological Survey of Canada, was born in Montréal and educated there under Alexander Skakel, and briefly at the University of Edinburgh. For a while, he worked in London for the firm of his uncle, Hart Logan; however, he discovered his true geological metier when he drew some exceptionally accurate maps of the coal seams of South Wales, while employed there as a mine manager. His cartographical work won him a reputation with the British scientific community which secured his appointment as director of the Geological Survey of Canada in 1842. Logan's task as director was at once scientific and political. The survey's continued existence depended on public and governmental appreciation, not of scientific research, but of discoveries of potential mineral resources, as well as skilfull public relations through annual reports and exhibitions. Logan particularly excelled at the latter, and his displays of mineral specimens won prizes for Canada at numerous international expositions in the 1850s and 1860s. Meanwhile, Logan continued his field research and mapping with professional assistance from his subordinates Alexander Murray (cartography), Robert Bell and Thomas Sterry Hunt (chemistry) and Elkanah Billings (palaeontology). Logan was the first native Canadian to be elected to the Royal Society (1851), and he was knighted in 1856. He endowed a chair and medal at McGill, where his friend J.W. Dawson was Principal. He retired from the Survey in 1869, and died in Wales in 1875.

Elizabeth Logan was an important figure in the development of nursing education and the nursing profession, both in Canada and internationally. She received her first degree in biology from Acadia University in 1932. She subsequently received her master's in nursing from Yale University in 1934. She went on to accept a position at Boston Children's Hospital as a nurse on a research study, which focused on children with cerebral palsy. In the 1940s, she joined the McGill School of Nursing, serving as a faculty member and eventually as acting director from 1963-1964 and director from 1964-1973. In the 1960s and 1970s, she did extensive consulting in the development of nursing internationally, and wrote several reports on behalf of the World Health Organization (WHO), as well as the Caribbean Community Secretariat. In 1972, she served as president of the Canadian Association of University Schools of Nursing (CAUSN, now CASN), when it became the first accrediting body for university nursing programs in Canada (from "The School's Undergraduate Programs Obtain Full Accreditation" by Madeleine Buck and "Elizabeth Logan" by Susan E. French in McGill Nursing In Focus: Building on Strengths, Autumn, 2010, p. 5, 15-17.)

David Logan was born on August 24, 1850, in Pictou, Nova Scotia.

He was the proprietor of D. Logan & Co., a wholesale and retail grocer store on Water Street in Pictou, Nova Scotia.

In 1876, he married Jenny Leetch (1855-1907). He died on February 4, 1937, in Pictou, Nova Scotia.