I have finally found the information I need on the family of Samuel and Mercy Sherman Barnard. I was trying to find proof to link their daughter, Esther, to the Esther Barnard who married Isaac Blake of Wrentham, MA. Finally, after a few hours of paid research and blind luck on the interenet, I found what I was looking for. Samuel and Mercy had four children, two of whom I still can't find any information for, but the other two -- Esther and Mercy/Grace, I have.

From "Genealogies of the Families and Descendants of the Early Settlers of Watertown, Massachusetts, Including Waltham and Weston" by Henry Bond (Little Brown & Company, Boston, 1855), p. 872-3

Mar. 20, 1703, wid. Mary, and her sons, William and Benjamin, for oe192, sold to Samuel Barnard 25 A., bounded N. by Sudbury Road, and land of Mary Browne; W. by Mary Browne, and partly by land of Serjt. John Fiske. By this deed, it appears that she retained some of the land assigned to her and her younger sons, and a subsequent deed shows its amount. Mar. 13, 1705-6, William and Benjamin B., sold to their brother Abraham, 9 1/2 A., bounded N. by Sudbury Road; W. by land of Abraham Browne; E. and S. by Samuel Barnard. By a deed dated Dec. 23, 1715, Capt. Abraham Browne conveyed to his son Jonathan, 14 A. "in easterly part of my estate," bounded E. by Samuel Barnard; S. by S. Barnard and John Fiske; N. by highway; W. by Abraham Browne. Mar. 18, 1730-1, James Nutting, of Wrentham, gunsmith, and Mercy, his wife, and Esther Barnard, spinster (both daughters of Samuel Barnard), for oe450, sold to John Browne (youngest son of Capt. Abraham), house, barn, shop, and 24 A. land, bounded N. by highway; W. by Jonathan and Samuel Browne, who held, by deed and legacy, that western portion, which their father obtained by settlement and purchase. The next day, Mar. 19, John Browne sold to his brother Jonathan, the same property for the same sum, subject to a mortgage of oe220, to Jonathan Nutting, of Wrentham. After this mortgage was paid off (as it was done), the ancient homestead was again vested in the Browne family.

Obtained from a researcher at the New England Genealogical Historical Society in Boston, MA (May 23, 2002). I had asked them to find information on what happened to Samuel, Mercy, Esther, Elizabeth, Mercy/Grace and Samuel Barnard since they disappeared from the records of Watertown.

"Samuel and Mercy Barnard last appear in the Middlesex Deeds on 28 Feb 1729, shortly after this, the only Samuel appearing in these deeds is no longer a Jr., suggesting that his father had died or removed. On Mar. 18, 1731, James Nutting, gunsmith, and Mercy, his wife, and Esther Barnard, spinster, all of Watertown, sell land and buildings therein. Samuel alone had sold the two girls this real estate on 8 Dec 1727, on which date James and Mercy Nutting were of Cambridge."

While this conflicts with the information from Bond's Watertown, records from Wrentham, show that a James Nutting, son of James and Marcy, was born Feb. 2, 1731-2 in Wrentham. There was also a record of another child's baptism a few years later. This tends to point towards Bond's Watertown information being more correct. There are two notions of deaths in Wrentham that could possibly be the death records for Samuel and Mercy (Sherman) Barnard. On page 408 of the "Early Vital Records of Norfolk County, Massachusetts to about 1850, Wrentham Births, Marriages and Deaths (Search and Research Publishing Corporation, Wheat Ridge, CO 80033, copyrighted 1998 on CD-Rom): Barnard, -----, wid. of -----, Aug. ----, 1738 and Barnard, Samuel, Mar. 9, 1738.