Hi Marie,
Eli and Lydia did not have the same father. In 1849, Polly (Eli's) mother married a man by the name of David Goings. At the time of the marriage, Polly was 42 and David was 23. Polly had six children when she married him. Polly and David had a son named Laurence Goings born in 1849(Goins) and later Lydia who was born in 1851.
See you soon,
Helena