The fonds contains professional and private correspondence from Emma Albani, the first Canadian-born singer of international fame, to Parisian publisher Henri Heugel.

There is business correspondence, 1792-1800, with letters from among others Alexander Mackenzie, Joseph Frobisher, Alexander Henry, Simon Fraser and Roderick Mackenzie. There are also minutes and resolutions of the Executors of McTavish in a bound volume; and a contemporary copy of the minutes of the executors of his will, 1805.

The fonds consists primarily of Logan's scientific work. A small percentage relates to the affairs of his family and to memorials to Logan after his death. The great majority of the papers consists of scientific correspondence from about 1820 to 1874, but mostly for the years following his appointment to the Survey in 1842. The letters deal with the collection, exchange and description of geological specimens, expeditions under the aegis of the survey, problems of research and scientific interpretation, scientific meetings, and visits by scientists. The number of correspondents, both individuals and learned societies, is very large, but the most substantial bodies of letters are from J.W. Dawson, geologist and Principal of McGill University, James Hall, paleontologist of the New York Geological Survey, Alexander Murray, Logan's chief assistant, and James Lowe of Grenville, Québec, who supplied Logan with specimens and appears to have been casually employed by him on surveying jobs and field trips. Other correspondents include Sanford Fleming, E.D. Ashe of the Québec Observatory, Thomas Sterry Hunt, and R.I. Murchison of the Geographical Society of Great Britain. Some letters pertain to political or social affairs, but usually in close connection with the scientific work of Logan or the Survey. These files contain copies of some of Logan's outgoing letters, as well as some letters addressed to other individuals, generally his assistants. Other scientific papers consist of field trip records (a journal kept during an expedition in 1845, a weather table kept on Lake Superior in the winter of 1846-1847, work records and astronomical readings for surveying projects, notes on mineral deposits, and lists of specimens), manuscripts of three scientific papers, as well as "Observations on the proposed Geological Survey", and manuscript and printed maps and geological schemata, including some by Logan of the Bay of Fundy, Labrador, and Hamilton, Ontario regions. Manuscript catalogues of specimens were prepared by Logan for the Paris Exhibitions of 1855 and 1867. Official reports include Logan's annual reports for 1842-1844, an overview of the work of the Geological Survey, 1866, two reports by Logan on prospects for mining on the north shore of Lake Superior, 1846, 1847, and one on mineral deposits around Rivière-du-Loup, 1853, as well as Logan's copy of his proposed Geological Survey Bill, 1844, and some copies of reports on mining and cartography prepared by others. Logan's financial records include expense accounts for Geological Survey expeditions, as well as other professional expenditures, such as books. His private and family life is reflected by a very brief diary of an Atlantic crossing in 1856, letters to and from his brothers James and Henry, his father, his uncle Hart Logan, and Hart Logan's partner John Fleming, covering the years 1772-1856. There are also baptismal and burial certificates, and legal documents, particularly bills of sale pertaining to James Logan's farm. Memorials to Logan after his death include J.W. Dawson's correspondence concerning the Logan Memorial Fund and Collection, 1881, and a manuscript biography by Alexander Murray. There is a chronological and author/recipient index to these papers.

Additional materials received from McGill Library's Rare Books and Special Collections consist of correspondence, 1837-1871; notices of admission to scientific and historical societies, 1842-1867; a history of the geological survey 1850; a report on mining locations addressed to B. Papineau, 1847; and correspondence with Robert Bell, 1861-1874.

The bulk of the Hunt papers consists of scientific correspondence, with a fairly large component of notes on scientific subjects. Most of the material dates from after Hunt's departure for the United States. With the exception of a letter of appointment to the Geological Survey of Vermont in 1845, all Hunt's correspondence (incoming, with copies of some outgoing) dates from the period 1863-1891, with the majority of items from the 1880s. There are a few letters of a social or personal nature, but most concern scientific matters: geological and chemical research problems, exchange of specimens, Hunt's theories and the controversies they stirred, his publications, negotiations for patents on some of his discoveries, the business of various scientific societies, and in particular the organization of the Geological Congress. Amongst his correspondents were James D. Dana (with whom he engaged in a heated quarrel over scientific theory), James Hall, Persifor Frazer, J.W. Dawson, and various members of the Geological Survey of Canada, such as G.M. Dawson, Robert Bell, Henry Y. Hind, and George Iles. Hunt's scientific notes mostly deal with special topics in chemistry, geology, mineralogy, railways, coal products and the controversy with Dana. There are also reading notes for geological texts, lecture notes for courses in geology, 1876, and chemistry, and indexes, apparently for Hunt's books. A manuscript on "Benjamin Franklin's Autobiography: an episode in its history", notes for a lecture on "People I have met", and sketches of family history represent Hunt's wider interests. There are also clippings of reviews of books and lectures by Hunt, biographical notices, reports on scientific themes and institutions, and news of the Geological Survey.

Greeley's papers comprise 15 letters, and the original typescript, with handwritten corrections of Chapters 11-18 of Arctic Discoveries.

This collection consists of incoming correspondence concerning some of Gardner's patients, 1898-1900.

Family correspondence chiefly from 1763 to 1820 and family history documents.

Letters and papers relating to employment with the Hudson’s Bay Company. These include letters of appointment, official announcements, lists of officers of the Hudson’s Bay Company, and an inventory the posts and officers in the Albany River district.

Collection consists of 36 autograph letters written to James Cameron and his son Archie. The correspondence includes letters by friends, associates, and members of the Cameron family in Toronto, Lake Beauport, Scotland, England, Hull, and Montreal. Subjects include family news, freemasonry, business (regarding deed of sales), factory work in Toronto, curling, and an April Fools' Day letter. With three extant envelopes.

The papers contain printed biographical materials: newsclippings on Craik's appointment as Dean (1889), his resignation (1901) and his death, as well as printed addresses by and in honour of him. There is also a typescript copy of the Medical Faculty's resolution at the time of Craik's death. A letter from Craik to a Miss Charleton (1904) thanks her for assistance in compiling an obituary.