Sugar treacle. The word appears as Melasus, Molassos, Malassos, Molossos, Molossus: see examples 15921694, N.E.D.
1705. [They] observd an inspissate Juice, like Molasses, distilling from the Tree.Beverley, Virginia, ii. 21.
1765. It is bartered in the French and Dutch colonies for melasses.Boston-Gazette, May 27.
1777. I have seen some of the melasses from corn-stalks . I would advise every person that makes melasses this way, &c.Maryland Journal, Dec. 2.
1789. If a merchant cheated in a bushel of salt or a gallon of melasses, the consequences were hardly perceptible.American Museum, v. 46/2 (Jan.).