Chaffee Family Genealogy Forum
This weekend I looked again at the reference in the Register. Following the footnote indication 24 there is a sentence which pretty much accepts that Rachel's mother was Miriam (Harmon) Bliss. It seems to me the thrust of the paragraph is that the marriage of Jonathan and Miriam came about not because of normal social intercourse shich might be expected in a community (in this case Rehoboth) but because of the previous marriage of Miriam's brother, Nathaniel Harmon, to Jonatha's sister Mary of Braintree.
Hope that makes sense to you.