Hi Judy, I am Joyce (Hines) Smith. My Daddy is your grandmother's (Jessie) brother. I'm assuming you are Pat's daughter.
Anyway, this is what I have finally found out regarding Talitha. Sarah Jane Shepard married Thomas Smith and they had Talitha. Thomas died and Sarah married John McNeal. On the census record I found it lists John, Sarah, Talitha, and
James McNeal. It notes James( age3) as son, but does not list Talitha (age 14) as daughter. It looks like Talitha used her stepdad's last name until she marries Levi Thomas Mercer, then used her legal last name (Smith). Hope this helps. I am on Ancestry under Hines/Colvin.