The maryage of Jonathan Rudd with Marcy his wife was upon the 19th Day of Defember 1678 … Mary Rudd the daughter of Jonathan Rudd & Marcy his wife was borne upon the eighth of October in the yeare of our lord 1679"
↑ The Bushnell genealogy has this "Mercy" as the daughter who marries Nathaniel Leffingwell. It appears that no other secondary source makes that identification. The birth records of five of Jonathan Rudd's children appear in the Norwich vital records. Only four appear in the Preston vital records, this "Mercy" excluded. That implies that this "Mercy" was not living when Jonathan had his four younger children entered in the Preston records which further implies that Nathaniel Leffingwell married the younger Mary. This analysis is likely but not proven.