My Greenland cousin who did a lot of research on the Moses line has only a little bit about Nathan b 1775. She just states that one of Nathan's children may have come to Jefferson Co., IA. That person was Missouri Greenland Chilcott, 1815-1886. She was the daughter of Nathan and Sarah Corbin Greenland (granddaughter of Moses) and married to Reuben Chilcott. She came to Jefferson co in 1853.
In a letter dated 1858, Keziah Shanafelt, another daughter of Nathan (b1775) states that her father and mother had 11 children