Very few of the McLeod papers actually concern the Observatory. However, his work for the railways and in Newfoundland is documented, as are his views on the education and employment of engineers. The basic record for the early part of his career is a diary kept from 1870 to 1875, regarding student days and early work on the Observatory. An essay, "Winter under canvas" (1868) describes an early surveying job, and a letter from his father (1872) inquires about his academic progress. His work for the railways is documented by three letters of recommendation, and two letters (one from Stanford Fleming) on the work of his colleagues in the West. The Newfoundland survey (1875) is described in McLeod's diary, a manuscript essay "Across Newfoundland" (1876), his printed reports and three letters. His work at McGill is represented by six letters (largely official acknowledgements of appointments), and McLeod's manuscript notes on McGill history. McLeod's concern with the engineering profession is reflected in two addresses on education and professional development, and copies of about a dozen letters to Sir Wilfrid Laurier (1906-1908), C.A. McGrath and E.F. Wurtele (1912), largely on the employment of engineers in the civil service.

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.