I don't know if this is the Mary you are looking for but I found a death certificate for Mary Elizabeth Busby online family search.org. Born 8/17/1880 in DeQueen, AR died from injuries in a car accident 5/17/1954 in Corpus Christi, Nueces County, Texas. Informant Geo Busby, father William Long mother unknown.
1900 Sevier County, Saline twp, Ar 7 July 1900 p164A 550/566 Busby Charles Jan 1882 18 married 2 years AR MS AL farmer Lizzie wife Jan 1888 18 married 2 years 1 child 1 living AR AL TN Laura dau Feb 1899 1 AR AR AR
Possible father, using name from death certificate, and second wife? On same page three households before Charles
548/562 Long William P July 1852 47 married 4 years AL GA GA farmer Frances wife - 1858 42 1 child 0 living SC - - Britton son Sept 1888 15 AR AL TN Wilson B son July 1889 10 AR AL TN Lula dau Nov 1891 AR AL TN Dollie dau Nov 1895 4 AR AL TN