Those Granville tax lists have been bothering me because I thought you had to be 16 years old to be on those colonial tax lists. If Robert the son of Robert and Sarah Abernathy was born on 27 Mar 1742, he is too young to be on a 1757 tax list if you have to be 16 years old to be on the list. James Abernathy is younger than Robert so I did a little looking and found this:
Males were on the tax list at either 14 years old or 16 years old which was the same age as the age for military service which was determined by the colony or county they were living in. According to the birth date of 27 Mar 1742 of Robert the age for the tax list must have been 14 in Granville County, NC.Males and females could witness deeds and wills at 13 years old.
In 1757, Robert, the son of Robert and Sarah Abernathy, is 16 years old born 27 Mar 1742 in Bristol Parish, Prince George County, VA and his brother James Abernathy on the tax list for the first time is 14 years old.