Hi Mary,
Robert and Rose did have a son John born at Hingham MA 1657 who married Mattithiah Aldredge and they had a son named John b. 1679/80 who died 2 weeks later. His next recorded son was also named John b. ? after 1684 and died 1697.
According to Ann Chaplin's Book, John only had 2 surviving sons: Isaac who married 16 Sep 1721 to Mary Summer and Jeremiah, unmarried with a Will dated 2 Dec 1715.
There is no additional information about Isaac and Mary. No children are listed. If anyone has knowledge of any Isaac descendants, please let us know.
Debra Dunbar Nowell, Dunbar DNA Administrator/Clan Dunbar