These spellings are from the Nevius book (Joannes Nevius and his Descendants, 1627-1900, by A. Van Doren Honeyman, 1900), but Gertie is also seen as Geertje and Sutfen as Sutphen as well as Sutphin.The following information is from Honeymans, p. 541-542.
Gertie Sutfen was the daughter of Abraham Sutfen (Sutphen) and Marytie (also seen as Marytje) Barkelo of Freehold, NJ.Gertie was probably baptized at Freehold on 29 Aug 1725 (name omitted from register).
Gertie married Peter Neefus (one of over two hundred variations of Nevius) about 1747, and they had the following children (possibly more), the first seven baptized at Bucks County, PA and the last at Hopewell, Dutchess Cocunty, NY: Maria Neefus, bpt 1748 Maragrietta Neefus, bpt 1750 Joris Neefus, bpt 1752, d. after 1775 Abraham Neefus (twin), bpt 1752, d. after 1775 Janitie Neefus, bpt 1754, d. after 1837 Cornelius Neefus, bpt 3 Jul 1757 Antje Neefus, bpt 14 May 1759 [others?] Sarah (supp.)Neefus, bpt abt 1764, d. after 1825 Elizabeth Neefus, bpt. 15 Apr 1767.
Honeymans was unable to find further information about Maria, Maragrietta, Cornelius, Antje, or Elizabeth.
We are hoping there are Sutphin sources out there that will prove that Maria Neefus is the elusive "Mary Naphew, b. 1748" who married Garret (Gerrit, Gerret) Van Pelt.