In the biography about her husband in Contemporary Biography of California's Representative Men, it is stated that Mary Potter was the daughter of William Potter of Petaluma.

In the 1852 California Census for Sonoma County, page #21, the following sequence of individuals are enumerated under William Potter, a 27 year old merchant born in Missouri (also last residence): Mary Potter, a. 19, bp. MO (also last residence); Louisa J. Potter, a. 1, bp. CA; E. H. Barnes, a. 24, bp. KY (last residence, MO), a merchant; Moses C. Briggs, a. 24, bp. MO (also last residence), a farmer, Elizabeth Potter, a. 24, bp. MO (also last residence); Mary Jane Potter, a. 13, bp. MO (also last residence); Jane K. P. Potter, a. 6, bp. CA; William Gordon, a. 13, bp. MO (also last residence); ---- Francisco, a. 13, bp. CA; ---- Lopee, a. 18, bp. CA.

In the 1860 Census for Petaluma City, Petaluma Post Office, Sonoma County, CA, there is a listing (page 579, line 25), for a Wm Potter, a 43 year old Teamster who was born in India [!] at dwelling 329. He has $800 of Real Estate and $1000 of personal estate. Also enumerated at the same dwelling is Susan Potter, a. 33, bp. Germany; Mary Potter, a. 14, bp: Illinois; Chas Potter, a. 1, bp. CA.

These appear to be two different William Potter famlies each with a young Mary in their household. Because of a correct age and census location match-up, the Mary who is the daughter of the second William Potter appears to be more likely the same individual who later married T. G. Cockrill.

The first William Potter ( 6 Jul 1825, Sedalia, Saline Co. (later Pettis Co.), MO - 15 Apr 1896, Midland Co.,TX) who had married (12 Sep 1849, District of San Rafael, Alta California) Mary Evaline Gordon (29 Apr 1833, MO - 24 Feb 1904), was a member of the Bear Flag "revolt" and was involved in a horse-capturing venture during the conflict. He and his family then resided in Mendocino County, CA for more than 26 years. His brother, James Knox Polk Potter (b. 1846, CA) also lived in Mendocino County and was married to an Evaline Hopper (b. 1849, CA) who was related to other Hopper Family members on this website in some not completely worked out lineage.

From Kit Fuller, a Hardin/Hopper/Potter researcher (2002):

Evaline's 1st cousin, once removed, was Charlie HOPPER, member of the famous 1841 Bidwell-Bartleson party. Evaline's 2nd cousin was Thomas HOPPER who traversed the plains in 1847. His grandson would marry Elizabeth POTTER BRIGGS' dau. Belle.

In "Bloomfield Cemetery Records, 1864-1967" copied by Susan Appleton (Santa Rosa Annex 929.379418 Bloomfield), there is a listing for "COCKRILL, Frankie, wife of T. G. Cockrill, died Dec. 1, 1872, age 27 yrs."

Mary Francis appears to have died a little over a month after giving birth to her daughter Frankie T.