From 1957 to 1963, Mountjoy worked for the
Geological Survey of Canada, first as a technical officer, then as a geologist. He left the survey to be an assistant professor at McGill University. In 1969, he was promoted to associate professor. In 1974, he was made a full professor. Between 1993 and 1998, Mountjoy was a Logan Professor. At the time of his death (2010), he was professor emeritus in the Department of Earth and Planetary Sciences, McGill University. Most of Mountjoy's research has concentrated on
Jasper National Park's Miette area, and in particular on its exposed coral reefs from the
Devonian period (395 million to 345 million years ago). Mountjoy, with
Queen's University professor
Raymond A. Price, mapped most of the Canadian Rockies between
Banff and
Jasper. This work produced cross-sections, which have become classic representations of the structure of a
thrust-
fold mountain belt and have been published in many textbooks. He also studied ancient and modern reef geology, carbonate petrology and diagenesis, carbonate reservoirs and stratigraphy. He visited and applied his knowledge to the geology of
Australia,
China and
Germany. He directed the research of over 50 master's and doctoral students, many of whom have gone on to become professors. Mountjoy died June 18, 2010, in
Montreal,
Quebec, Canada. ==Honours==