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.

These McGill papers are entirely concerned with his property and estate. They comprise legal documents and copies of letters (some in McGill's hand) concerning his land holdings on St. Paul St., Montréal, in Stanbridge, and in Detroit. McGill's cash book, 1809-1815, and copy by W.D. Lighthall of a deed of conveyance to McGill of some land formerly occupied by the city fortifications, 1805, are also included, as is a blue-print and sketch by W.D. Lighthall of the site of McGill's St. Paul St. house. Estate papers comprise a probate of McGill's will, copied by Alice Lighthall, and his executor's cash book.

Frobisher's papers comprise a letterbook of the North-West Co. containing copies of letters written by Frobisher from April 1787 to October 1788, two original letters to Simon McTavish, 1796, and one from him, 1787, business and legal documents, largely concerning the estate of James McGill, 1810-1834, and a diary, 1806-1810, mostly a record of where he dined.

This material comprises a group of official documents, and correspondence among various partners. The official documents include four articles of agreement for partnership between various Montréal companies, largely with McTavish, Frobisher and Co., 1790-1802, and a memorandum on the effect of exchange differences on the partners' shares (approximately 1826). The partners' correspondence, approximately 1792-1808, contains letters from Simon McTavish, Isaac Todd, and Alexander Mackenzie concerning provisions, business agreements and loans. A letter from William McGillivray to Mr Justice Reid discusses family matters. One financial ledger for the North West Company contains business accounts and records transactions. The bulk of entries are dated from January 1810 to November 1825, with some entries dated 1861.

File contains 10 items which are copies of legal documents from the life James McGill. 1 indenture contract between James McGill and Edward William Gray, 1795; 1 indenture contract between Andrew Turner and Alexander Allison, 1817; 5 contracts of the selling of real estate for a property on St. Paul St ., Montreal once owned by McGill (1774-1822); 1 document on the removing of the old wall and fortifications of Montreal; 1 document on the bankruptcy and sale of Hoyle, Henderson and Gibb Co.; 1 document, an obligation of the estate of James Caldwell.

These are various business papers of Simon McTavish and include partnership agreements with William and Duncan McGillivray, William Hallowell, Roderick McKenzie, Angus Shaw and James Hallowell, 1806 and drafts of agreement for seven years between McTavish, Frobisher and Company and John Fraser of London, Simon McGillivray and John Tullon, 1805.