Find Ancestors

Can anyone give me any help with the following?
Part of my wifes family have been traced to San Francisco around 1880. We are very keen to find any more information on what seems to have been a well connected family - we have the following information.
James and Margaret Clancy had a family between 1865 and 1883 - they produced the following - Margaret (c1865), John - involved in the Canadian Pacific Railway construction - driving the last peg in San Francisco according to family legend, James, George, Winifred, Kate/Katherine, Lillian, Elizabeth, Rose, Mary(poss Mamie) and Frances Gertrude on 26/2/1883. My wife is decended from Frances.
We know that Mary married William Fitzgerald - one time Sherriff of San Francisco.
We are keen to find any more details of the family.
Frances Clancy married Thomas SHIRDAN and travelled to Shanghai, where he died. They had a daughter Helen Mary. Frances remarried becoming a CLAY and lived with Helen Mary in San Francisco between the first and second world wars. Helen married Philip CAPON in Shanghai, before taking the Empress of Canada to the USA poss in the 1930s
Sounds like we know a lot but would like to put dates and details to the story and give the names some meaning. Any information or pointers as to where to look will help.
Ian

There's a great site here for California death records. I like it because it usually gives the mother's maiden name.
http://vitals.rootsweb.com/ca/death/search.cgi

Google........."Sheriff of San Francisco"Fitzgerald
First site has info & picture of him.

Malcolm.

California Passenger and Crew Lists, 1893-1957
Name: Helen Lauriston Capon
Arrival Date: 25 Mar 1931
Age: 25
Occupation: Housewife
Birth Date: abt 1906
Birthplace: Shanghai, China (Nationality: American)
Gender: Female
Ethnicity: American
Ship Name: Chichibu Maru
Port of Arrival: San Francisco, California
Port of Departure: Yokohama, Japan
Destination: San Francisco, California, United States
Last Residence: China
Friend's Name: J E McGuigar

Travelled with Philip John Lauriston Capon
Age: 28
Occupation: Army Doctor
Place of Birth: Frome, England
Last Permanent Address: Shanghai, China
(Other details were same as for Helen)

England & Wales, FreeBMD
Birth Index: 1837-1983
Name: Philip John L Capon
Birth: Dec 1902 - Frome, Somerset

California Passenger and Crew Lists, 1893-1957
Name: Frances Gertrude Clay
Arrival Date: 28 Feb 1934
Age: 54 years 6 months
Birth Date: abt 1879
Occupation: None
Birthplace: San Francisco, California, United States
Gender: Female
Ethnicity: American
Ship Name: Chichibu Maru
Port of Arrival: San Francisco, California
Port of Departure: Shanghai, China
Destination: London
Last Residence: China, Shanghai
Friend's Name: J F Barrett

Looks like "married Shanghai, China"
Possible date of 4/23/27

Travelling with her was William Samuel Clay, age 49 (assuming husband)
Occupation: Merchant (crossed out and "retired" inserted)
Place of Birth: Berks, England

Thank you all very much.