found an obit. for Mary F. Nickerson, 85, who died the afternoon of 1 Jul 1936. The obit noted her native home was Bradford, ME, and her husband had died many years ago.

Note: That fact suggests the John M. Nickerson from California (died 2 Dec 1942, Los Angeles) is not the same John Murray Nickerson married to our Mary Frances (Speed) Nickerson.

The obit. also indicated Mary F. was survived by daughter Celia M [Mabel] Nickerson, son Walter Nickerson, and another daughter in Portland [Sylvina "Vinie" Nickerson].

Further, Mary F. is shown on Josiah Nickerson's [father-in-law] cemetery record--she was born 1851 and died 1936.

Citations:
"Obituaries," The Bangor Daily News (Bangor, Maine), 18 Jul 1936, Saturday, col. 1, image copy, Newspaper.com (https://www.newspapers.com/image/ : accessed 4 December 2020), entry for Mrs. Mary F. Nickerson, age 85, her husband died many years ago; citing printed newspaper article by same paper and date, p. twenty-three. Maine, U.S., Faylene Hutton Cemetery Collection, 1780-1990," surname range: Nason-Norton, database with images, Ancestry.com (2019) (https://www.ancestry.com/imageviewer/collections : accessed 5 December 2020), cemetery record of Josiah Nickerson (accession 5118) showing Mary F. [Mary Frances (Speed) daughter in law and wife of John Murray Nickerson], born 1851, died 1936, Greenlawn Cemetery, Swanville [Waldo County, ME]; citing Maine, Faylene Hutton Cemetery Collection, ca. 1780-1990, Salt Lake City, Utah, USA: FamilySearch, 2016.

Thanks,
John
Contributor: John E. Lapham, D.Mgt. (47580378) • [email protected]

1860 U.S. census,", Penobscot County, Maine, population schedule, Bradford, p. 44 (penned), dwelling 319, family 321, entry for Washington Speed, age 41, Celia W. [Whittmore (Coy)] Speed, age 38, and Mary F. [Frances] Speed, age 9, image, Ancestry.com (2009) (http://www.ancestry.com : accessed 4 December 2020); citing NARA microfilm publication M653, images reproduced by Family History Library Film 803447.