This line has not been the focus of my research to date, so admittedly my records are not complete, nor entirely sourced.It's possible that I, or my contributors, have made some mistakes-- especially since there seems to be frequent repetition of male and female names across generations!
That said, the only similar reference I find in my records is to Temperance Tallmage, wife of Suetonius (or Sweton) Grant; parents of Janet Grant (1735-1774); mother of William Dummer Powell (1755-1834).
With regard to the various John Powells in this line:
I show William Dummer Powell's grandfather, John Powell(-1741), married to Anne Dummer (1684-1764).
I show William Dummer Powell's father, John Powell (1715-1799), married to the aforementioned Janet Grant.
*** According to my records, "Ye Family of Dummer" indicates that this John Powell (1715-1799) had a younger brother also named John Powell, who married a Martha Winslow.
I show that William Dummer Powell had a brother, John Powell (1755-), who "...was with General Burgoyne's Army at Cambridge after the battle of Saratoga, 1777, but nothing further is known of him."
So, I'm afraid I cannot account for your Ms. Tallmadge, wife of John Powell.