This series forms the core of the fonds: correspondence, diaries and memoranda books, estate records, accounts and other records created or accumulated by Christian Daniel Claus, his son William Claus, and his grandsons; plus records accumated by Alexander McKee, Deputy Superintendent of Indian Affairs, 1794-1799 (see also MG 19 F 16), and Prideaux Selby (d. 1813), Assistant Secretary of Indian Affairs, 1797-1809. The McKee and Selby papers came into the custody of William Claus when he succeeded McKee in office. The series includes documents accumulated by William Claus, Jr. (d. 1824), who served with the 54th Regiment, in Europe, Jamaica, South Africa and India; and John Claus (d. 1812) who served with the 84th Regiment. The entire series is available on microfilm reels C-1478 to C-1485.
Volumes 1-12 and 13-19 form two overlapping series, each having a chronological sequence. Commissions and land records (volume 20), notebooks and memoranda (volumes 21-22) and biographical and genealogical notes (volume 23) were largely separated from the main series. English translations of letters in Mohawk found within the first series of correspondence form volume 24. The "Claus-Haldimand" correspondence relating to the use of Indians in warfare, 1777-1784, forms volume 25 while volume 26 holds transcriptions of it and letters relating to its segregation. The introduction to MSS Finding Aid 41 provides a summary explanation of that segregation and the transfer of militia records to RG 8, Series I.
The "Genealogical Notes" in volume 23 include other items, notably the two-page deed of sale entitled "Sale of a negro to Daniel Claus, 26 July 1763".
The correspondence includes myriad integral postal covers, 179 of which, covering the period from 1767 to 1878 (with emphasis on 1779 to 1829) have been noted in the philatellic finding aid. They illustrate the postal services linking Germany, Great Britain, New York and Quebec, Nova Scotia,Upper and Lower Canada, the Province and later the Dominion of Canada. Straight-line postmarks are well represented, with Coteau du Lac (1819), Halifax (1810-1813), Kingston (1802-1819), Montreal (1779-1824), Niagara (1802-1805), Quebec (1780-1809) and York (1817-1822). The Halifax circular type (1816-1829) and Montreal's unique second postmark of October 15, 1774 are represented in the series.
