Daniel Coleman - Sons Daniel and Daniel Darby

Based on this info from his profile notes, I don't think he had a son named Daniel Darby. It seems, rather, he had one son named Daniel Jr. and another named Darby:

"Daniel2 was the only child of Robert Coleman and Elizabeth Grizzell to retain both King & Queen and King William Co. land. For that reason, it is very likely he was also the father of the Darby Coleman described in Wingfield’s History of Caroline County, Virginia, 1975, p. 417. "In the Spotsylvania County Records of 1738, mention is made of William Coleman of St. John’s Parish in King William Co., son and heir of Darby Coleman, deceased of King & Queen Co."

For purposes of this record, and until evidence proves otherwise, Daniel Coleman2 was the father of Daniel Jr., John, Thomas, Darby and Grizzell."

So unless there is documentation indicating he had sons named Daniel and Daniel Darby, this one is probably just Daniel Jr. not Daniel Darby Jr. For one thing, his father wasn't Daniel Darby Sr. The Darby name came from his wife's maiden name, which is why they named a son Darby:

Daniel Darby Coleman, Jr.