I only located one source, but who knows what their source was?
Duggins, L. Adelia, Lineage of Allan Cameron Duggins and His Wife, Clarice Isabella Henson,(Burlington, Vt.: Chedwato Service, 1966, 89 pgs.), "Electronic," 37, Jacob Robertson s/o Charles Robertson & ? m Elizabeth Wheelock.
Same source shows Charles (f/o Jacob) was the s/o Col. Charles ROBERTSON and Susannah CUNNINGHAM.