ISABEL TROMBLEY was born in 1830 in of Blackfeet Nation, U.S.A.. She died on 11 Dec 1910 in of Blackfeet Nation, U.S.A.. She married ISAAC TROMBLEY.
[Notes] They had the following children:
M i ALFRED TROMBLEY was born in 1880. He died on 21 Jun 1909.
This very well could be your Isabel Mercier since her maiden name is not listed, and there is no reason to believe that Alfred was her only child. I realize it's been a long time since you posted but if you never did find what you were looking for, I know a few Trombleys on the Blackfeet reservation who I could ask.