Hi Lois,
Merrill Whittier b 1813 is the eldest son of Henry Whittier and Louisa W. Leighton. Henry is Louisa's second husband. Her first was John Day. The family came from Lincoln county Maine. After Merrill was born they moved to New Brunswick with John Day Jr and Merrill. Then they had Louisa, Henry and Elizabeth. I am a descendent of Louisa Leighton and John Day. I am also trying to get back further than that. There are plenty of trees with information on Henry Whittier Sr., but nothing on the Leighton side that I have found yet.
I believe that the David Leighton (Layton) may be a brother of Louisa Leighton's but can't be sure.
Hope that helps.
Arlene