I am assuming that Rebecca's maiden name is Dennison and she is the widow of an Atchison, as she was 42 at the time of her marriage to Nathaniel Pettit, and also she was living with a Catherine Dennison, age 80, after Nathaniel's death, so it is a good bet that the elder Mrs. Dennison is her mother.

Fayette Co. birth records list Mrs. Rebecca Oettit as the owner of an unnamed slave born June 1855.