On FamilySearch there is a marriage between Isaac Johnson and Catherine Mintoft
Nov 25, 1814 at Skirpenbeck Yorkshire.
There are a few family trees on ancestry which give Isaac Johnson's dates as
b. 17 Nov 1793 Yorkshire d. 22 May 1876 Lanark (these seem to be taken from his death registration)
These trees give dates for Catherine as
b. 24 Feb 1793 Yorkshire d. 19 Mar 1876 Lanark - I haven't found a death registration for her so far.
On the 1861 Canadian census Isaac (67) and Catherine (68) are both living in Montague, Lanark with the following
James Johnson 12 b. Cda
Jane Scott 16 b. Cda Servant
Robert Scott 35 b. Ire labourer
Charity Scott 26 b. Cda (ancestry trees show Charity married Robert Scott and she died 15 Feb 1908 at Smith Falls with a birth date of 13 Aug 1834)
With them are their children - Catherine 7, James 4, Caroline 3, William 2.
On the 1871 census 75 year old Isaac and 78 year old Catherine are by themselves in Montague, Lanark South.
Debbie