Diann, It is likely that your Mary is a descendant of Liner Pidcock. Liner is the s/o Horatio. The family was in Mercer Co., Ky, then Hopkins Co. where Horatio d. abt 1828. His wife, Ann, and five sons then migrated as follows: Amos and Liner stayed in Ky. Ira, William and Ann to Crawford Co., Mo. Bro. Baker went to Arkansas. You can find Liner on the 1850 and I believe 1860 Todd Co., Ky census. Liner had a daughter, Mary E., b. 1838 and his son, Horatio, also had a Mary.
Will be happy to discuss further if you are interested.