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Nathaniel was both my father's grandfather (by marriage) and his uncle (by blood)
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I have no idea what this means. If the J. C. PRICE mentioned on this forum and married to Glendora GRANT is truly your father's father's brother, and not an older cousin he called Uncle, then your father's grandfather is not Nathaniel (unless there is something here I don't know about). Seen your father's post, if his father is James N. PRICE brother of J. C. PRICE then his grandfather is not Nathaniel PRICE.