Is she the Marie A. Fitzsimmons listed as daughter of James and Anna M. Fitzsimmons on the 1930 census? If so... this looks like the death record for her mother:
Anna M. Fitzsimmons
Born 26 June 1892 in Pennsylvania
Died 22 Jul 1972 in Los Angeles County
If that's Mary/Marie's mother, you could look for her obituary and hopefully it will list Mary along with her married name.
Here, I found Anna's obituary:
Los Angeles Times - July 24, 1972 - Page A20
FITZSIMMONS, Anna M. - widow of the late James Fitzsimmons, the founder of Fitzsimmons Stores, Ltd., Retail Food Chain, beloved mother of Mrs. Catherine M. Stemmier, Mrs. Margaret Surridge, Mrs. Mary Ann Kelly and Mrs. Anna Mae Capelle, loving sister of Mrs. Betty Reals, Mrs. Julia Alcott, Mrs. Helene Doorly and Mrs. Dorothy Adams; also survived by 12 grandchildren and 6 great-grandchildren. Rosary Tuesday 8 p.m. and Funeral Mass, both at St. Francis de Sales Church, Sherman Oaks, J. T. Oswald Mortuary, North Hollywood directors.
If you'll go to my profile and send me a message, I have some additional info for you.