Sources & Information:
Mordecai Ellis married @ age 28, Rebecca Clark married @ age 26.

Ancestrycom: Trees > OneWorldTree > Mordecai Ellis shows the following difference in date of death for Lt. Mordecai Ellis as 20 Feb 1709.

Mordecai was a surveyor of highways on 7 June 1677, @ age 26, and earned the military rank of lieutenant. He and his wife were members of the Sandwich Church. All children of this family probably born in Sandwich, MA. He was administrator with his mother of his brother's (John Ellis Jr.) estate 7 June 1677. When his estate was settled without a will, property was listed: "a dwelling house, 5 acres on the N side of the old field, 1/3 of the meadow called the Point, and over 245 pounds."

Mordecai Ellis, date of death, in Ancestors and Descendants of Zeba Ellis of Ellisville, MA., indicated as 1790, believe this to be a typo error. Note spelling in IGI listing as follows: MORDECAY ELLES, son of John ELLES, born 24 March 1650, Barnstable, Sandwich, MA., IGI Pg.. 12080.

FamilySearch-Ancestral File. indicates Mordecai Ellis date of death as 20 Feb 1709, Sandwich, Barnstable, MA. Note difference in date of death given for Mordecai above as 5 Feb 1709-10. SEE NOTES INDIVIDUAL NOTES UNDER REBECCA CLARK.

Vital Records of Sandiwch, Massachusetts, Volume One, Page 5, indicates the following: "Mordecay Elles the son of John Elles born the 24th of March [1650/1]". Also Volume One, Page 18, indicates the following: "Mordicai Ellis the sone of John Ellis was borne the 24th of March, Anno Dom. 1650." In same Volume One, Page 29, Births Marriages and Deaths, Earmarks, Town of Sandwich, is found the following: "[The original page is missing, but this page was copied by H.G.O. Ellis into pages 509 &510 of Book 3. Mr. Ellis was dealing with a very worn & torn page. He made guesses which we have corrected from other sources. Since this is the only non-original vital record which we have had to use, we print the Ellis copy and our corrections of it immediately following.]"
"Mordecai Ellis died Feb 5 in 1600 perhaps 80 or 90. [A 20-acre lot was laid out to the heirs of Lieut. Mordecai Ellis, deceased on 7 March 1706/7 (Sandwich Woodlot Records p.37).
Hence, his death date was probably February 5, 1706/7."

Additional Sources:
Mrs. Harriet S. Dusenberry, Bozman, Montana, Letters & chart 1984.
The Ellis Family Tree of Lois Ann Ellis, Warren, Michigan.
Col. Harry H. Ellis, USA, Dallas, TX. [Deceased].
The N.E.H.G.S. Register, Oct 1965, Pg.. 260-262.
The Register, Jan 1966, Pg.. 30-31.
Ancestors and Descendants of Zeba Ellis, of Ellisville, MA.
Anthony A. Miller, Calabasas, CA. 10-09-93 Letter. & Pedigree Chart.
Michael A. Shoemaker, < http://www.pacwest.net/bigshoe/ellext.html >.
See Pane-Joyce Genealogy @
<http://alephO.clarku.edu/~djoyce/gen/reprot/rr06/rr06_190.html>.
RootsWeb’s WorldConnect Project: Lt John Ellis of Sandwich.