As Eileen said there is a marriageNov. 6, 1849 for Thomas Oliver and Johanna Doyle. Witnesses are shown as James Doyle and Rose McKinn
Johanna is shown as a spinster so should not have been married before.
There is also a death for a Johanna Oliver, died April 26, 1898 , age 78 years, died Job's Cove, burial Northern Bay born Low Point
There is a tree at ancestry.com that shows Johanna POWER married 1. John Coole 2. Thomas Oliver
her parents are shown as Thomas Timothy POWER and Margaret WALSH
so IF they are correct then the Johanna Doyle who married Thomas Oliver on Nov. 6, 1849 is not your woman BUT it seems odd that there would be a marriage for the date you shown and for the man you show with a wife Johanna if not the right couple.
I am wondering if DOYLE should be COOLE in the marriage of 1849 and if it was a second marriage for her even though it says she was a spinster.