the following is from Caroline Lewis Kardell and Russel A. Lovell, Jr., Vital Records of Sandwich, Massachusetts to 1885,(3 vols.; Boston, Mass.: New England Historic Genealogical Society, 1996), vol. I, pg. 26:
"Elezebeth Briggs the Daftar of Samuell Bridgs was Boarne the .3 of 2: 1665"
it is my understanding that she was the daughter of Samuel Briggs and ELIZABETH Ellis
Lydia B. (Phinney) Brownson and Maclean W. McLean, "Lt. John and Elizabeth (Freeman) Ellis of Sandwich, Mass.," NEHGR: 119:172 (July 1965) contains the following:
Elizabeth Ellis, daughter of John-1 & Elizabeth (Freeman) Ellis, m., about 1664, Samuel-2 Briggs (John-1).
Check that source and Sandwich VR for more information about descendants of that couple
In Edna Anne Hannibal and Claude W. Barlow, "John Briggs of Sandwich, Massachusetts and His Descendants" (Palo Alto, Calif., 1962), pg. 1, it is stated that Samuel Briggs (son of John of Sandwich) m. Bennet, the 2nd daughter of John and Elizabeth (Freeman) Ellis ... however, Brownson and McLean (in the above-referenced NEHGR article) assert that Elizabeth Freeman ("b. about 1645"), the eldest child of Lt. John & Elizabeth (Freeman) Ellis, m. Samuel Briggs
Brownson and McLean:
"We believe that there can be little doubt that Samuel Briggs' wife was a daughter of Lt. John Ellis, particularly since his first two daughters were named Elizabeth and Bennet, presumably after his wife's mother and the grandmother, Bennet (Hodsoll) Freeman, and that the printed accounts which claim that Briggs married the daughter Bennet Ellis are mistaken, since ... Bennet Ellis was born in 1649, yet the wife of Samuel Briggs had a daughter born in April 1665 when Bennet Ellis would have been barely sixteen years old."