Thank you Sandra and amondg. It is the 1870 census that convinces me that Thomas Henry is not the same person as Thomas, the son of Thomas Duncan and Catherine Johnston as Catherine Johnston was born in Ireland and had died in 1856, and Thomas didn’t die until 1886. This 1870 census implies that Thomas Henry Sr. was deceased.
Also, there is a death of a Kate Duncan in 1881, age 7 yr 2 months, and 21 days with parents Thomas and Julia which gives the places of birth of her parents and it gives Toronto, Ontario for Thomas and E. Stoughton for Julia which is correct for Julia. Although the age is slightly off, since their daughter Catherine was born Nov 13, 1874, and her date of death is between Sept 25 and Dec 1, and I think it is Sept 25. The occupation for Thomas is unreadable but I think it is Thomas Henry and Julia. If this info is correct, Thomas Henry was born in Toronto, not Gloucester Township, Carleton Co., Ontario.
I found the index card for the naturalization in 1882 for Thomas H. Duncan but I didn’t find the actual application, with Dob Nov 10, 1843. Is there an application?
I will look for the family in 1861 in Toronto based on the 1900 census. Thanks again. Peggy