While most researchers who have posted their family trees at Rootsweb's WorldConnect name Truman Powell and Elizabeth Carpenter m. Connecticut as the parents of Elizabeth Powell (b. 2 July 1727) (b. 12 March 1726) or (b. 18 February 1727/8) who married Edward Richmond, there are listings for Thomas Powell (and wife Abigail Hallock).
Thomas Powell's family can be found here in "Long Island Genealogies" by Mary Powell Bunker, b. 1820. Thomas & Abigail (Hallock) Powell had a daughter Elizabeth, born 2 July 1727, in Bethpage, who married Micah Post. One family tree with Thomas Powell as the father of Elizabeth Powell, lists Edward Richmond as her 1st husband (m. 1745, Sharon, CT) and Micah Post as husband number two whom she married in 1761. That doesn't work however, because that same family tree lists the birthdate for the youngest Richmond child as 1784. The will of Thomas Powell III, made 2 February 1855, names daughter "Elizabeth Post."
The (Truman) Powells and Richmonds were early settlers of Spencertown/Austerlitz, New York.
Thomas Powell of Bethpage, Long Island, New York had a daughter, Elizabeth, b. 2 July 1727, who married Micah Post. Truman Powell had a daughter, Elizabeth, born in Connecticut, who was probably born 18 Feb in either 1727 or 1728. [Hope to find more definitive information about her birthplace and date]