John Shattuck GREGORY (28 Dec. 1875, Placer Co., CA [per WW I Reg.] was son of John Henry GREGORY. There are discrepancies online as to the name of his mother, who died before the census of 1880.
Census of 1880, Nine, Placer, CA, GREGORY, John H., 27, was born in CT of parents b. Ireland, but mother Mary, 60, was born at sea?
John S., 4, CA CT CA.
FindaGrave has John GREGORY (1852 - 1928) bu. Rocklin Cem., Placer Co., CA. There's a photo of his tombstone and a bit about him.
John S.GREGORY m1. 21 July 1902, Placer Co., CA [per Mountain Dem., 26 July 1902], Mabel Eloise LOVEJOY (Mar. 1879, CA - 15 May 1904, El Dorado Co., CA). They had a child b. & d. 1904.
John S. GREGORY m2. 1907, CA, Marilla Rebecca STARK (1881, OR - 1930). They had been married three years in 1910, Petaluma, Sonoma, CA. John and his parents were all born in California, per the 1910 census, but his father was born in Connecticut per the 1880 census & Ohio per the 1920 census. In 1910, census said Marilla's parents were born in Kentucky & Ohio, but in 1920, Wisconsin & Utah.
Census of 1910, Petaluma, Sonoma Co., CA, GREGORY:
John S., 34; Marilla, 29; & her son "Zekel" MARTIN, CA OH OR.
The next entry in 1910 was Andrew J. STARK, 36, NV KY IL.
Roseville, Placer, CA, 1920, GREGORY, John S., 44; Marilla R., 39; Willie, 8.
MARTIN, John E. [John Ezekiel?], 20.
Roomers were STEPENSON, Elda, 24; Hale, 6; Harold, 4; & VanTASSELL, Hilda, 16.
William GREGORY (12 Je. 1911, Sonoma Co., CA - Je. 1976, Washington, DC) m. Vivian O'DONNELL, per Ancestry.com.
San Francisco, San Fran., CA, 1930
MARTIN, Abbie L., 31, CA CA OH, div.
MARTIN, Robert K., 8; William J., 6; Dorothy L., 5
Stepfather-in-law GREGORY, John S., 54, CA CT CA, wid.
GREGORY: Wm. H., 19, & Jack M., 8.
You should be able to find news articles on the death of Thomas Anthony GREGORY (27 Sep. 1939, San Francisco - 22 Nov. 1973, Marin Co., CA, bu Mt. Olivet). He was stabbed and died in the San Quentin Hospital. Ancestry has the death certificate.
--not my family