In 1895, Mary O'Toole (age 22) was living in St. Paul, Ramsey, Minnesota. he lived next door to Bridget O'Toole (age 72), who was born in Ireland.
In 1940, Mary (age 66) was living with her husband Oscar and son Robert in Los Angeles, California. 
On 3 Nov. 1897 Mary A. O'Toole married Oscar Fontaine in Ramsey County, Minnesota. 
On 6 Aug. 1940 Mary died in Los Angeles, California. Cause of death was chronic myocarditis. She was 67 years old. Her birthplace was listed as St. Paul, Minnesota. Her parents' were listed as "Thomas O'Tool" and "Katherine O'Halloran", both born in Minnesota. The informant for her death was her husband, Oscar Fontaine. Mary was buried in Holy Cross Cemetery. 
↑ "Minnesota State Census, 1895," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MQ61-MPL : 22 February 2021), Mary O'Toole, St. Paul city, Ward 09, Ramsey, Minnesota; citing p. 40, line 3, State Library and Records Service, St.Paul; FHL microfilm 565,803.
↑ "United States Census, 1940," database with images, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:K9ZF-FZC: accessed 24 Apr 2022), "Mary Fontaine" in household of Oscar Fontaine, Los Angeles District 8, Los Angeles, California, United States; citing ED 60-628, line 50, sheet 1B, NARA microfilm publication T627 (Washington D.C.: National Archives and Records Administration).
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MW19-DWF : accessed 14 July 2017), Mary Fontaine in household of Oscar Fontaine, St Paul Ward 6, Ramsey, Minnesota, United States; citing ED 67, sheet 6B, line 74, family 132, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 853; FHL microfilm 1,820,853.