If Georgiann was born in 1842, she would have been 18 years old in the 1860 Census.
The 1860 Census of John Riddle does not show a Georgiann. She could have already been married by then. We don't know yet, because an 1860 Census record hasn't been found yet for her, or her husband.
An 1850 Census record for John Riddle might show her on there, but again, no 1850 Census record has been found yet for him.
Other alternatives are to find her death record, to see if lists her parents on there, or a marriage record for her that lists her parents.