I have finally found evidence that William Roberts Abel, b. 1749in Lebanon, New London, CT, is the son of David Abel and Alice Roberts.
The birthdate given in the Abell Family in America is Jan. 7, 1755, (thus my slight doubt) but William believed his birthday to be Jan. 14, 1749, although he had no document to prove it. Other information in the file confirms this to be the same William Roberts Abel listed in the book.
William married Lois Merry and eventually moved to Kitley, Upper Canada. They had nine children, including Lyman Abel (my GGG Grandfather) b. 1793, d. 1869.
I have a large file from the National Archives containing William Abel's Revolutionary War Pension Application papers. There are letters of affidavit from relatives and friends, some of which might be interesting to other researchers of this line.