Melva, I went to that site, but I already had everything in more detail. I have been collecting Shipman data for at least 20 years. First I studied the Edward Shipman family of Saybrook, Ct, but this family was definitely English, and the name Magdalena was definitely German so that did that.
I then studied the Harmon Shipman family of Greenwood , Harmony twp, Sussex Co, NJ, but this family was so thoroughly studied and Harmon had left a will naming all his children, plus Harmon's first child, William was born in 1756, far too late to be a Parent of Magdalena (Shipman) Girton. Harmon had a dau Lenah (Magdalena) from his second wife born abt 1768, to young to be are Magdalena. Enough said about Harmon Shipman.
Like you I then went to Matthias Shipman b1726 the son of Jacob b abt 1697 m to Maria Rosina Katherina Hendershot. Mathias was born at Hunterdon Co, NJ, Moved to what is now Warren co, NJ where he died and was buried at St.James Lutheran "Straw" Church at what is now Warren Co,NJ. Because Matthias was a Lt Colonel in the Hunterdon Co Militia, his family was highly documented they mainly lived and died at Warrne Co, and were buried at the St.James Lutheran "Straw" Church, there children were baptized at the Straw Church.
Matthias Shipman had a sister Lenah, b abt 1733, for awhile I thought she might be our Magdalena, no she married Ezekiel Cole, they lived at Reading Twp, Hunterdon Co, three of there children served in the 1792 Militia, Obediah, Jacob, and Ezekiel. Ezekiel was a Justice of the peace in Readington, he died in 1817.