Martha Norine Rowley Gentilini
Birth
19 Dec 1936
San Francisco, San Francisco County, California, USA
Death
23 Jul 2017 (aged 80)
Burial
Cypress Lawn Memorial Park
Colma, San Mateo County, California, USA
https://www.findagrave.com/memorial/280654490/martha-norine-gentiliniThe gravestone says that she was a mother and grandmother, but neither it nor the page gives the names of her husband or children.
She and her sisters are listed as living in the 2019 Debrett's, but her sisters died in 2009 and 1998, respectively.
They are daughters of Julius Henry Rowley (1905-1982), of the Rowley Baronets.
Jean Alma Rowley
Birth
3 Sep 1946
San Francisco, San Francisco County, California, USA
Death
2 Sep 2009 (aged 62)
San Mateo County, California, USA
Burial
Cypress Lawn Memorial Park
Colma, San Mateo County, California, USA
https://www.findagrave.com/memorial/76206718/jean_alma-rowleyThough Jean's Findagrave page mentions "Rowley" as her only surname, the gravestone itself gives her married surname as "Garcia".
Violet Lee Rowley
Birth
1951
San Francisco, San Francisco County, California, USA
Death
4 Sep 1998 (aged 46–47)
San Francisco, San Francisco County, California, USA
Burial
Cypress Lawn Memorial Park
Colma, San Mateo County, California, USA
https://www.findagrave.com/memorial/87652503/violet_lee-rowley