It is confusing when there are so many Georges, Williams, and Johns!!
The parents of Mary Etta Dyal were George Washington Dyal and Maria Elizabeth Rooks.
Harriet Dyal is not in my line so I have not documented her, but from various online sources, here is what I believe to be true:
John Dyal Sr. had twin sons, John Dyal Jr and George Dyal.This George Dyal married Sarah Polk.Their daughter was the Harriet Dyal you have in your line.Online sources say she is the mother of James Nathaniel Dyal, who was the father of the George Washington Dyal who married Emma Florence.Remember, I have not documented this, but this appears to be the trail you need to follow.Perhaps you could find someone who is descended from this George Dyal to find the documentation you need to verify.
Here is a database you can check, but be aware there are some errors in it.I sent correction a few years ago, but it was never corrected.Use it only as a guide to aid in your research, but always find documents to support your work.Sometimes people post these databases and never update them, so the errors get copied by others and passed on like a chain letter.Always seek actual records to verify your generations -- never rely only on the online family trees.