This marriage notice appears in Reid's Marriage Notices and is a transcription of what appeared in "The Church" newspaper:
24 November 1838: At Bowmanville, Robert Roy Mackie of Yarmouth, London District to Angeline H. Gilbert of Darlington, by Rev. T.S. Kennedy
The township of Yarmouth is in today's Elgin County, in southwestern Ontario. In the timeframe of the marriage, the province was divided into districts, not counties; hence, Yarmouth was in London District.
Online family trees have this Robert Roy Mackie as the son of William Mackie & Helen Darlington. Born 11 February 1813 in Scotland; died 10 March 1848 in Clinton, Iowa.
Angeline was still alive at the time of the 1870 US Census, living in Clinton, Iowa, living with daughter, Henrietta Gast, aged 28, born in Canada (born ca. 1842).
I found a possible for Angelina (noted only as A. Mackey), aged 38, living in Geauga County, Ohio), with H. (female), aged 18, and W. (male), aged 16, all born in Canada, living with family of I. Lamoreaux, a farmer, aged 47, also born in Canada. It is likely, that Robert Roy did not died in Iowa, but rather in Ohio.
1850 US Census Geauga County, Ohio
Lamoreaux, Isaac, aged 38, farmer, b. Canada Lamoreaux, Sophia, aged 30, b. Canada Mackey, Angeline, aged 28, b. Canada Mackey, Charles, aged 12, born Canada Mackey, Henrietta, aged 8, born Canada Mackey, William, aged 6, born Canada