The bulk of Gill's papers concern his consulting work for the mining industry and for government. Only two small files relate to his teaching career. Gill's work as mining consultant is documented by 124 maps, 48 designed by Gill himself, showing structural geology of various regions in eastern Canada, and mineral deposits of gold, iron, zinc and molybdenite, not only in Canada, but also in the Malartic gold fields in Peru (1929-1968). The papers also contain his report on iron ore in Labrador (1929) and two reports by W.F. James and J.E. Gill to the Newfoundland government, assessing prospects for gold in the Rainbow and Kayak Concessions, Labrador (1933), areas prospected by R.B. D'Aigle, see his papers, Section IX: Professions And Trades. IX). Three field notebooks record summer research expeditions (1935, 1947-1948). Three reports by Peter Eakins, a former student of Gill, describe the Malartic mine (1951, 1955-1956); there is also a report by Eakins on the Wasa Lake Goldfield (1950), and one by J.B. Gilliatt on the Wabana Iron Mines (1949). Gill also raised a file of correspondence and reports on Newfoundland mineral resources (ca 1955-1969). Finally, there are two boxes of petrographic slides, one with laboratory reports, a box of mineral samples collected for the Québec Ministry of Mines, and 4 photographs of mining concerns with which Gill was involved. His teaching activities are reflected by a file of plans, reports and memoranda on the organization of the Geology Department Map Library (1959-1969) and an outline with some draft chapters of a student's thesis (1969).

This fonds documents the administration, research activities, and development of the McGill Sub-Arctic Research Laboratory and its successor, the McGill Sub-Arctic Research Station. Records include administrative and operational files, research project documentation, scientific data, publications, correspondence, and related papers generated through the station's activities.

The fonds is particularly significant for documenting the establishment and early years of the laboratory, including records relating to its founding, organization, and initial operations. The records provide evidence of the evolution of sub-arctic research at McGill University and the station's role in supporting scientific investigations in northern Quebec.