If you could provide any further information you might have; the more information you provide, the more help the G2G community can offer you. Any information you might think is trivial, could be useful.
Do you know any of Cornelius Mastin's family's names? His wife? Children? Parents? when and where he was born? when (and where in Canada) he arrived? Dates are most helpful, even a guess at the year can sometimes be a good point to start at.
I would also check familysearch.org - it's free, and it is a wealth of information.
Good luck, and feel free to edit your question with additional information if you find any.