In Great Harwood, Lancashire England there is a Margaret Lavelle that died in 1915 age 79.
Lavelle is a very unusual name for that area and I am thinking this could be Mary's mother.
I cant find any Margaret Lavelle of the correct age in the 1901 or 1911 England Census.
In the 1911 Ireland census there is a Margaret Lavelle, Widow, age 74 in East Doogort, Slievemore, Mayo.
Would this be near the place above?
Regards
Dave