John Caston was mentioned in the 22 October 1750 will of his apparent father-in-law John Croxton. John Croxton gave to the children of John Caston one shilling each. John Caston also witnessed the will, but on 18 October 1757 when the will was proved he was not present. On 17 January 1758, another subscriber, Thomas Barker, stated that he saw John Caston witness the will. [Essex County, Virginia, Will Book 11, pages 40–41.]