Be careful not to confuse with him William Riley Bailey, born Mar 1838, who married Mary Ulery.

Her death certificate records Mary Jane Bailey, age 78 years 3 months 2 days, born 28 Jan 1841 in Bath Co., Ky, died 30 Apr 1919 in Jessamine Co., Ky, widowed, father Robert Clark, mother’s maiden name Lucy Williams, both born in Bath Co., Ky, cause of death mitral insufficiency, informant Thomas Bailey, Nicholasville, Ky, burial in Maple Grove Cemetery, Nicholasville.

Her year of birth is probably really 1842, since her parents were not married until April 1841, and she was listed as age 8 in the 1850 census.

She may be the Mary Clark in this household:
1870 census of Bath Co., Ky, White Sulphur precinct, enumerated 15 June, lists on p. 8 as family #230:
Williams, Alfred, 42, farmer; Mary, 81, b. N.C.; Clark, Mary, 27, b. Ky.

1900 census of Bath Co., Ky, Bethel precinct, enumerated 21 June, lists on pp. 20B-21A as household #385/387:
Boyd, Edmond, 36, single, b. Aug 1863, farmer. Bailey, Mary, 58, servant, widowed, b. Jan 1842, mother of 3 children, 3 living.

1880 census of Bath Co., Ky, Polksville precinct, enumerated 12 June, lists on p. 153 as family #150/152:
Baley, Mary, 40; Peachy, 9, dau; Thomas, 7, son; Alfred, 4, son. All born Ky Ky Ky.