Hi Jamie
She is listed in the 1910 Census as Mary Heard
According to the US Social Security Death index
I believe the correct spelling of her first name to be Merril
You can also find her on find a grave listed here
https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=90542472&ref=acom
I believe the mothers maiden name to be Jennie Blizzard she was listed as Annie in the 1880 Census
I believe this to be her Find A Grave Link
https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=71164864&ref=acom