Apparently, I was not clear about the second wives...etc..etc...or Citations. The question was specific towards Mary Shotwell.
For one, all of the Records of Elizabethtown were burned in a fire along with church records and a lot of the history had to be replicated as well as possible years later through grave stones and family history...etc.
The first Samuel Marsh Jr. was married twice. His first wife was Mary Trimmins 1650-1750. Their Source Citations include American Genealogical-Biographical Index (AGBI) A genealogical dict. of the first settlers of New England, showing three generations of those who came before May 1692, By James Savage. Boston; Ancestry Family Trees; Connecticut, Church Record Abstracts, 1630-1920; New Jersey, Compiled Census and Census Substitutes Index, 1643-1790 and U.S. Also a Quaker Meeting Records, 1681-1935, more specifically (Woodbridge, Rahway & Plainfield Monthly Meeting, N.J. - Births 1705-1901, Deaths 1705-1908 and Marriages 1712-1885) referencing Samuel Marsh & Mary Shotwell #276. In this record on page 276, it states: Samuel Marsh of Woodbridge was married to Mary Shotwell Borough of Elilzabeth, Essex County of Rahway. Mary Trimmins records were most probably burned.