''All that certain Tract Piece or Parcel of Land lying in the bounds of Elizabeth-Town or Westfield afsd Beginning at a white oak tree Marked on the North side with number fifty six Thence running North East ten chains to a stake, Thence North West five chains to a stake, Thence North East six chains and Twenty five links, Thence North West Twenty chains to a stake standing in the line of Lot number fifty-five, Thence South west Sixteen chains and twenty five links to a Walnut tree marked with the number fifty five, Thence South East Twenty five chains to the first mentioned white oak tree, Containing and to Contain forty acres of land be the same more of less, Butted and bounded as followeth viz, on the south west and South East by Land left for highways, on the North East by Land belonging to ye Revnd Mr Nathaniel Hubbell on the North West by Land belonging to the above named William Miller.''
Source: Union County Ancient Deeds, Vol. 1, p. 55
Text copied from: http://archiver.rootsweb.com/th/read/NJUNION/1999-09/0936333686
A chain is 66 feet long and consists of 100 links. 25 rods is 1650 feet and 16 rods and 25 links is 1072.5 feet. A square mile is 640 acres or 6400 square rods. Thus an acre is 10 square rods or 43,256 square feet (66 x 66 x 10).